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000
FXUS65 KCYS 311713
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
1113 AM MDT MON AUG 31 2015

.SHORT TERM...(TODAY THROUGH WEDNESDAY NIGHT)
ISSUED AT 431 AM MDT MON AUG 31 2015

SCATTERED SHOWERS WILL CONTINUE EARLY THIS MORNING AHEAD OF A
SHORTWAVE MOVING UP FROM THE SOUTHWEST WITHIN THE RIGHT ENTRANCE
REGION OF AN UPPER LEVEL JET MAX. A FEW LIGHTNING STRIKES HAVE BEEN
OBSERVED OVER NORTHWEST COLORADO THE PAST FEW HOURS...SO CANT
RULE OUT AN ISOLATED STORM OVER THE SOUTHERN WYOMING MOUNTAINS AS
WELL. THE COLD FRONT LOOKS TO BE DRAPED ACROSS NORTHERN WYOMING
ACCORDING TO 4AM SFC OBS AND SHOULD BEGIN TO MOVE ACROSS OUR
EASTERN COUNTIES AROUND SUNRISE. AHEAD OF THE FRONT...SOUTHWEST
WINDS HAVE BECOME QUITE BREEZY OVERNIGHT WITH GUSTS ON AVERAGE OF
25 TO 35 MPH...WITH A FEW SPOTS ALONG AND WEST OF THE LARAMIE
RANGE REPORTING HIGHER SPEEDS. WILL SEE THESE WINDS PERSIST
THROUGH THE MORNING AS THE FRONT SLIDES SOUTH ACROSS THE
PLAINS...AND WINDS BEHIND THE FRONT WILL VEER TO THE NORTH
REMAINING GUSTY AT TIMES.

TEMPS WILL BE COOLER TODAY IN THE POST FRONTAL AIRMASS WITH
READINGS EXPECTED TO REMAIN IN THE 70S AND 80S. AS THE SFC HIGH
DROPS INTO THE CENTRAL PLAINS...SFC WINDS WILL VEER FURTHER TO A
SOUTHEASTERLY UPSLOPE COMPONENT THROUGH THE AFTERNOON. UPPER LEVEL
FLOW WILL REMAIN OUT OF THE SOUTHWEST WITH A CONTINUED STREAM OF
SUBTROPICAL MOISTURE...SO MAINTAINED A CHANCE FOR SHOWERS AND
TSTMS THIS AFTERNOON OVER THE MOUNTAINS BUT ALSO EXPANDED SLIGHT
CHANCES EASTWARD WITHIN THE UPSLOPE REGIME...ALTHO COVERAGE IN
THIS AREA WILL REMAIN VERY ISOLATED. ALTHO LLVL MOISTURE WILL BE
HIGHER THAN YESTERDAY...GUSTY WINDS ARE STILL A GOOD BET WITH THIS
ACTIVITY.

TUESDAY WILL BE WARMER AS THE COLDER AIRMASS RETREATS TO THE EAST
AND ANOTHER SHORTWAVE EMBEDDED IN SOUTHWEST FLOW LOOKS TO MOVE
OVERHEAD BRINGING ADDITIONAL CHANCES FOR AFTERNOON SHOWERS AND
TSTMS BUT MAINLY TO THE MOUNTAINS. A STRONG UPPER LOW WILL DIG
INTO THE PAC NW ON WEDNESDAY AND SHOULD DEEPEN THE LEESIDE
PRESSURE TROUGH THRU WEDNESDAY MORNING/AFTERNOON. SFC WINDS WILL
INCREASE IN RESPONSE WITH GUSTS OF 30 TO 35 MPH POSSIBLE THRU THE
AFTERNOON OUT WEST AS 700-500 MBS WILL RAMP UP TO 25 TO 35 KTS. A
SOMEWHAT DRIER AIRMASS WILL MOVE IN FOR WEDNESDAY WHILE TEMPS
CONTINUE TO WARM UNDER AMPLIFIED SOUTHWEST FLOW. PRECIP CHANCES
WILL BE LESS OVERALL BUT CANT RULE OUT A TSTM OR TWO OVER THE
MOUNTAINS.

.LONG TERM...(THURSDAY THROUGH SUNDAY)
ISSUED AT 431 AM MDT MON AUG 31 2015

THURSDAY...DRY AND MILD DAY UNDER SOUTHWEST FLOW ALOFT AND WITH
LIMITED LOW AND MID LEVEL MOISTURE TO FUEL THUNDERSTORMS.

FRIDAY...FLOW ALOFT REMAINS SOUTHWEST. HOWEVER...WITH AN INCREASE IN
LOW AND MID LEVEL MOISTURE AND LOW LEVEL UPSLOPE WINDS...EXPECT
ISOLATED LATE DAY SHOWERS AND THUNDERSTORMS MAINLY ALONG AND EAST OF
THE LARAMIE RANGE.

SATURDAY...NEXT MORE POTENT SHORTWAVE TROUGH ALOFT MOVES ACROSS
MONTANA. EXPECT ISOLATED LATE DAY THUNDERSTORMS TO DEVELOP IN OUR
COUNTIES ALONG A CONVERGENCE BOUNDARY.

SUNDAY...MOSTLY DRY DAY IN THE WAKE OF A COLD FRONT AS DRIER AND
MORE STABLE AIRMASS MOVES IN.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY MORNING)
ISSUED AT 1113 AM MDT MON AUG 31 2015

VFR EXPECTED THROUGH THE PERIOD. A FEW AFTERNOON AND EVENING SHOWERS
AND THUNDERSTORMS POSSIBLE MAINLY AROUND THE SRN WY MTNS THIS
AFTERNOON WITH BRIEF LOCALIZED MVFR AND GUSTY AND ERRATIC WIND.

&&

.FIRE WEATHER...
ISSUED AT 431 AM MDT MON AUG 31 2015

WIDELY SCATTERED LIGHT RAIN SHOWERS WILL CONTINUE TO MOVE NORTHEAST
ACROSS THE DISTRICT THIS MORNING. BREEZY SOUTHWEST WINDS OF 25 TO 35
MPH WITH A FEW HIGHER GUSTS WILL ALSO PERSIST AHEAD OF A COLD FRONT
THAT WILL DROP SOUTH ACROSS THE EASTERN PLAINS AFTER SUNRISE.
WINDS ACROSS THE PLAINS BEHIND THE FRONT WILL SWITCH TO THE NORTH
WITH GUSTS TO 25 MPH...THEN WILL VEER TO THE SOUTHEAST THROUGH THE
AFTERNOON. A FEW SHOWERS AND TSTORMS WILL RETURN TO THE MOUNTAINS AND
NEARBY EASTERN PLAINS THIS AFTERNOON AS ENERGETIC SUBTROPICAL FLOW
REMAINS OVERHEAD. COOLER TEMPS TODAY WILL BE SHORT-LIVED WITH VERY
WARM...DRY AND BREEZY CONDITIONS LOOKING TO RETURN TO SOUTHEAST
WYOMING THROUGH THE END OF THE WEEK.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&

$$

SHORT TERM...RJM
LONG TERM...RUBIN
AVIATION...RE
FIRE WEATHER...RJM



000
FXUS65 KCYS 311713
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
1113 AM MDT MON AUG 31 2015

.SHORT TERM...(TODAY THROUGH WEDNESDAY NIGHT)
ISSUED AT 431 AM MDT MON AUG 31 2015

SCATTERED SHOWERS WILL CONTINUE EARLY THIS MORNING AHEAD OF A
SHORTWAVE MOVING UP FROM THE SOUTHWEST WITHIN THE RIGHT ENTRANCE
REGION OF AN UPPER LEVEL JET MAX. A FEW LIGHTNING STRIKES HAVE BEEN
OBSERVED OVER NORTHWEST COLORADO THE PAST FEW HOURS...SO CANT
RULE OUT AN ISOLATED STORM OVER THE SOUTHERN WYOMING MOUNTAINS AS
WELL. THE COLD FRONT LOOKS TO BE DRAPED ACROSS NORTHERN WYOMING
ACCORDING TO 4AM SFC OBS AND SHOULD BEGIN TO MOVE ACROSS OUR
EASTERN COUNTIES AROUND SUNRISE. AHEAD OF THE FRONT...SOUTHWEST
WINDS HAVE BECOME QUITE BREEZY OVERNIGHT WITH GUSTS ON AVERAGE OF
25 TO 35 MPH...WITH A FEW SPOTS ALONG AND WEST OF THE LARAMIE
RANGE REPORTING HIGHER SPEEDS. WILL SEE THESE WINDS PERSIST
THROUGH THE MORNING AS THE FRONT SLIDES SOUTH ACROSS THE
PLAINS...AND WINDS BEHIND THE FRONT WILL VEER TO THE NORTH
REMAINING GUSTY AT TIMES.

TEMPS WILL BE COOLER TODAY IN THE POST FRONTAL AIRMASS WITH
READINGS EXPECTED TO REMAIN IN THE 70S AND 80S. AS THE SFC HIGH
DROPS INTO THE CENTRAL PLAINS...SFC WINDS WILL VEER FURTHER TO A
SOUTHEASTERLY UPSLOPE COMPONENT THROUGH THE AFTERNOON. UPPER LEVEL
FLOW WILL REMAIN OUT OF THE SOUTHWEST WITH A CONTINUED STREAM OF
SUBTROPICAL MOISTURE...SO MAINTAINED A CHANCE FOR SHOWERS AND
TSTMS THIS AFTERNOON OVER THE MOUNTAINS BUT ALSO EXPANDED SLIGHT
CHANCES EASTWARD WITHIN THE UPSLOPE REGIME...ALTHO COVERAGE IN
THIS AREA WILL REMAIN VERY ISOLATED. ALTHO LLVL MOISTURE WILL BE
HIGHER THAN YESTERDAY...GUSTY WINDS ARE STILL A GOOD BET WITH THIS
ACTIVITY.

TUESDAY WILL BE WARMER AS THE COLDER AIRMASS RETREATS TO THE EAST
AND ANOTHER SHORTWAVE EMBEDDED IN SOUTHWEST FLOW LOOKS TO MOVE
OVERHEAD BRINGING ADDITIONAL CHANCES FOR AFTERNOON SHOWERS AND
TSTMS BUT MAINLY TO THE MOUNTAINS. A STRONG UPPER LOW WILL DIG
INTO THE PAC NW ON WEDNESDAY AND SHOULD DEEPEN THE LEESIDE
PRESSURE TROUGH THRU WEDNESDAY MORNING/AFTERNOON. SFC WINDS WILL
INCREASE IN RESPONSE WITH GUSTS OF 30 TO 35 MPH POSSIBLE THRU THE
AFTERNOON OUT WEST AS 700-500 MBS WILL RAMP UP TO 25 TO 35 KTS. A
SOMEWHAT DRIER AIRMASS WILL MOVE IN FOR WEDNESDAY WHILE TEMPS
CONTINUE TO WARM UNDER AMPLIFIED SOUTHWEST FLOW. PRECIP CHANCES
WILL BE LESS OVERALL BUT CANT RULE OUT A TSTM OR TWO OVER THE
MOUNTAINS.

.LONG TERM...(THURSDAY THROUGH SUNDAY)
ISSUED AT 431 AM MDT MON AUG 31 2015

THURSDAY...DRY AND MILD DAY UNDER SOUTHWEST FLOW ALOFT AND WITH
LIMITED LOW AND MID LEVEL MOISTURE TO FUEL THUNDERSTORMS.

FRIDAY...FLOW ALOFT REMAINS SOUTHWEST. HOWEVER...WITH AN INCREASE IN
LOW AND MID LEVEL MOISTURE AND LOW LEVEL UPSLOPE WINDS...EXPECT
ISOLATED LATE DAY SHOWERS AND THUNDERSTORMS MAINLY ALONG AND EAST OF
THE LARAMIE RANGE.

SATURDAY...NEXT MORE POTENT SHORTWAVE TROUGH ALOFT MOVES ACROSS
MONTANA. EXPECT ISOLATED LATE DAY THUNDERSTORMS TO DEVELOP IN OUR
COUNTIES ALONG A CONVERGENCE BOUNDARY.

SUNDAY...MOSTLY DRY DAY IN THE WAKE OF A COLD FRONT AS DRIER AND
MORE STABLE AIRMASS MOVES IN.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY MORNING)
ISSUED AT 1113 AM MDT MON AUG 31 2015

VFR EXPECTED THROUGH THE PERIOD. A FEW AFTERNOON AND EVENING SHOWERS
AND THUNDERSTORMS POSSIBLE MAINLY AROUND THE SRN WY MTNS THIS
AFTERNOON WITH BRIEF LOCALIZED MVFR AND GUSTY AND ERRATIC WIND.

&&

.FIRE WEATHER...
ISSUED AT 431 AM MDT MON AUG 31 2015

WIDELY SCATTERED LIGHT RAIN SHOWERS WILL CONTINUE TO MOVE NORTHEAST
ACROSS THE DISTRICT THIS MORNING. BREEZY SOUTHWEST WINDS OF 25 TO 35
MPH WITH A FEW HIGHER GUSTS WILL ALSO PERSIST AHEAD OF A COLD FRONT
THAT WILL DROP SOUTH ACROSS THE EASTERN PLAINS AFTER SUNRISE.
WINDS ACROSS THE PLAINS BEHIND THE FRONT WILL SWITCH TO THE NORTH
WITH GUSTS TO 25 MPH...THEN WILL VEER TO THE SOUTHEAST THROUGH THE
AFTERNOON. A FEW SHOWERS AND TSTORMS WILL RETURN TO THE MOUNTAINS AND
NEARBY EASTERN PLAINS THIS AFTERNOON AS ENERGETIC SUBTROPICAL FLOW
REMAINS OVERHEAD. COOLER TEMPS TODAY WILL BE SHORT-LIVED WITH VERY
WARM...DRY AND BREEZY CONDITIONS LOOKING TO RETURN TO SOUTHEAST
WYOMING THROUGH THE END OF THE WEEK.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&

$$

SHORT TERM...RJM
LONG TERM...RUBIN
AVIATION...RE
FIRE WEATHER...RJM



  [top]

000
FXUS63 KUNR 311709
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
1109 AM MDT MON AUG 31 2015

.UPDATE...
ISSUED AT 852 AM MDT MON AUG 31 2015

UPPER WAVE CONTINUES TO PUSH THROUGH THE NORTHERN PLAINS. RADAR
STILL INDICATES SHOWER ACTIVITY BEHIND THE COLD FRONT ACROSS
SOUTHWEST INTO CENTRAL SD. ADDED SOME ISOLATED SHOWERS THROUGH
THE DAY FOR ANY RAIN THAT MIGHT BE REACHING THE GROUND...ALTHOUGH
OBS STILL SHOW PRETTY DRY AIR SO IT MAY REMAIN VIRGA. INCREASED
CLOUD COVER TO REFLECT CURRENT TRENDS...BUT REST OF FORECAST LOOKS
ON TRACK FOR NOW.

&&

.SHORT TERM...TODAY THROUGH TUESDAY NIGHT
ISSUED AT 327 AM MDT MON AUG 31 2015

WATER VAPOR IMAGERY SHOWS STRONG UPPER WAVE CROSSING CNTRL TO ERN MT
INTO NRN WY. SURFACE ANALYSIS SHOWS LOW PRES ACROSS THE WRN/CNTRL
DAKOTAS AHEAD OF THE UPPER WAVE...WITH A COLD FRONT QUICKLY PUSHING
THRU ERN MT/CNTRL WY TOWARD THE CWA. TEMPS ACROSS THE CWA ARE IN THE
60S/70S...EVEN 80S ACROSS THE DOWNSLOPING N/NE BLKHLS. BEHIND THE
FRONT...OBS SHOWING TEMPS DROPPING INTO THE 50S WITH WINDS OF 15 TO
30 GUSTING TO 30 TO 40 MPH. RADAR SHOWS SHOWER ACTIVITY CROSSING WRN
SD...HOWEVER NEARLY ALL THE PRECIP IS VIRGA WITH LITTLE TO NO RAIN
REACHING THE GROUND. THE COLD FRONT WILL PUSH THROUGH NE WY TO WRN
SD IN THE NEXT 4/5 HOURS OR SO...AND CLEAR SCNTRL SD BY MID TO LATE
MORNING. HRRR SUGGESTS WINDS WILL GENERALLY BE 15 TO 25 MPH WITH
GUSTS TO 30 TO 40 MPH...BUT IS ALSO SHOWING STRONGER WINDS ACROSS
THE WRN SD PLAINS NORTH AND EAST OF THE BLKHLS. WIND ADVISORY
CRITERIA WINDS ARE EXPECTED...HOWEVER JUST FOR COUPLE HOURS OR SO
IMMEDIATELY AFTER THE FROPA. COULD SEE LINGERING SHRA ACTIVITY EARLY
THIS MORNING AS MODELS ARE HAVING A HARD TIME DECIDING HOW MUCH
PRECIP WILL REACH THE GROUND. WILL LEAN TOWARD A DRY FORECAST FOR
NOW CONSIDERING THE LATEST RADAR IMAGERY...BUT WILL REASSESS CLOSER
TO 12Z. OTHERWISE A DRY DAY IS EXPECTED WITH MUCH COOLER
TEMPERATURES AND CLEARING SKIES. HIGHS WILL REACH THE UPPER 70S TO
UPPER 80S. TEMPS TONIGHT WILL DROP INTO THE 50S TO LOWER 60S. RETURN
FLOW WILL SET UP BY MON NIGHT/TUE MRNG WITH WARMER TEMPS
EXPECTED. HIGHS WILL RETURN TO THE MID 80S TO MID 90S. DRY WEATHER
WILL CONTINUE TUE/TUE NIGHT WITH BROAD SWRLY FLOW ALOFT
PERSISTING.

.LONG TERM...WEDNESDAY THROUGH SUNDAY
ISSUED AT 327 AM MDT MON AUG 31 2015

THE UPPER TROUGH WILL REMAIN OVER THE NORTH AMERICAN PACIFIC
COAST THROUGH MOST OF THE WEEK...EVENTUALLY MOVING INLAND BY THE
WEEKEND AS ANOTHER IMPULSE DROPS INTO THE UPPER TROUGH FROM THE
NORTHWEST. THIS PATTERN WILL LEAD TO CONTINUED VERY WARM
TEMPERATURES OVER THE NORTHERN PLAINS BOTH WEDNESDAY AND THURSDAY.
FRIDAY AND SATURDAY WILL BE SLIGHTLY COOLER...WITH MUCH COOLER
TEMPS ON SUNDAY AND MONDAY BEHIND A RELATIVELY STRONG COLD FRONT
WHICH WILL PASS THROUGH THE AREA EARLY SUNDAY. DRY WEATHER IS
EXPECTED ON WEDNESDAY AND THURSDAY WITH A CHANCE OF THUNDERSTORMS
EACH DAY FROM FRIDAY THROUGH THE WEEKEND AS A SERIES OF UPPER
IMPULSES CROSS THE REGION AND COOLER AIR FLOWS IN AT THE SFC.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY)
ISSUED AT 1105 AM MDT MON AUG 31 2015

VFR CONDITIONS EXPECTED THROUGH THE PERIOD. A NARROW BAND OF -SHRA
WILL MOVE ACROSS SCNTRL SD THROUGH THIS AFTN. GUSTY NORTHWEST
WINDS ACROSS THE SD PLAINS WILL DIMINISH THIS AFTN.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
WY...NONE.
&&

$$

UPDATE...POJORLIE
SHORT TERM...13
LONG TERM...10
AVIATION...BUNKERS



000
FXUS63 KUNR 311709
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
1109 AM MDT MON AUG 31 2015

.UPDATE...
ISSUED AT 852 AM MDT MON AUG 31 2015

UPPER WAVE CONTINUES TO PUSH THROUGH THE NORTHERN PLAINS. RADAR
STILL INDICATES SHOWER ACTIVITY BEHIND THE COLD FRONT ACROSS
SOUTHWEST INTO CENTRAL SD. ADDED SOME ISOLATED SHOWERS THROUGH
THE DAY FOR ANY RAIN THAT MIGHT BE REACHING THE GROUND...ALTHOUGH
OBS STILL SHOW PRETTY DRY AIR SO IT MAY REMAIN VIRGA. INCREASED
CLOUD COVER TO REFLECT CURRENT TRENDS...BUT REST OF FORECAST LOOKS
ON TRACK FOR NOW.

&&

.SHORT TERM...TODAY THROUGH TUESDAY NIGHT
ISSUED AT 327 AM MDT MON AUG 31 2015

WATER VAPOR IMAGERY SHOWS STRONG UPPER WAVE CROSSING CNTRL TO ERN MT
INTO NRN WY. SURFACE ANALYSIS SHOWS LOW PRES ACROSS THE WRN/CNTRL
DAKOTAS AHEAD OF THE UPPER WAVE...WITH A COLD FRONT QUICKLY PUSHING
THRU ERN MT/CNTRL WY TOWARD THE CWA. TEMPS ACROSS THE CWA ARE IN THE
60S/70S...EVEN 80S ACROSS THE DOWNSLOPING N/NE BLKHLS. BEHIND THE
FRONT...OBS SHOWING TEMPS DROPPING INTO THE 50S WITH WINDS OF 15 TO
30 GUSTING TO 30 TO 40 MPH. RADAR SHOWS SHOWER ACTIVITY CROSSING WRN
SD...HOWEVER NEARLY ALL THE PRECIP IS VIRGA WITH LITTLE TO NO RAIN
REACHING THE GROUND. THE COLD FRONT WILL PUSH THROUGH NE WY TO WRN
SD IN THE NEXT 4/5 HOURS OR SO...AND CLEAR SCNTRL SD BY MID TO LATE
MORNING. HRRR SUGGESTS WINDS WILL GENERALLY BE 15 TO 25 MPH WITH
GUSTS TO 30 TO 40 MPH...BUT IS ALSO SHOWING STRONGER WINDS ACROSS
THE WRN SD PLAINS NORTH AND EAST OF THE BLKHLS. WIND ADVISORY
CRITERIA WINDS ARE EXPECTED...HOWEVER JUST FOR COUPLE HOURS OR SO
IMMEDIATELY AFTER THE FROPA. COULD SEE LINGERING SHRA ACTIVITY EARLY
THIS MORNING AS MODELS ARE HAVING A HARD TIME DECIDING HOW MUCH
PRECIP WILL REACH THE GROUND. WILL LEAN TOWARD A DRY FORECAST FOR
NOW CONSIDERING THE LATEST RADAR IMAGERY...BUT WILL REASSESS CLOSER
TO 12Z. OTHERWISE A DRY DAY IS EXPECTED WITH MUCH COOLER
TEMPERATURES AND CLEARING SKIES. HIGHS WILL REACH THE UPPER 70S TO
UPPER 80S. TEMPS TONIGHT WILL DROP INTO THE 50S TO LOWER 60S. RETURN
FLOW WILL SET UP BY MON NIGHT/TUE MRNG WITH WARMER TEMPS
EXPECTED. HIGHS WILL RETURN TO THE MID 80S TO MID 90S. DRY WEATHER
WILL CONTINUE TUE/TUE NIGHT WITH BROAD SWRLY FLOW ALOFT
PERSISTING.

.LONG TERM...WEDNESDAY THROUGH SUNDAY
ISSUED AT 327 AM MDT MON AUG 31 2015

THE UPPER TROUGH WILL REMAIN OVER THE NORTH AMERICAN PACIFIC
COAST THROUGH MOST OF THE WEEK...EVENTUALLY MOVING INLAND BY THE
WEEKEND AS ANOTHER IMPULSE DROPS INTO THE UPPER TROUGH FROM THE
NORTHWEST. THIS PATTERN WILL LEAD TO CONTINUED VERY WARM
TEMPERATURES OVER THE NORTHERN PLAINS BOTH WEDNESDAY AND THURSDAY.
FRIDAY AND SATURDAY WILL BE SLIGHTLY COOLER...WITH MUCH COOLER
TEMPS ON SUNDAY AND MONDAY BEHIND A RELATIVELY STRONG COLD FRONT
WHICH WILL PASS THROUGH THE AREA EARLY SUNDAY. DRY WEATHER IS
EXPECTED ON WEDNESDAY AND THURSDAY WITH A CHANCE OF THUNDERSTORMS
EACH DAY FROM FRIDAY THROUGH THE WEEKEND AS A SERIES OF UPPER
IMPULSES CROSS THE REGION AND COOLER AIR FLOWS IN AT THE SFC.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY)
ISSUED AT 1105 AM MDT MON AUG 31 2015

VFR CONDITIONS EXPECTED THROUGH THE PERIOD. A NARROW BAND OF -SHRA
WILL MOVE ACROSS SCNTRL SD THROUGH THIS AFTN. GUSTY NORTHWEST
WINDS ACROSS THE SD PLAINS WILL DIMINISH THIS AFTN.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
WY...NONE.
&&

$$

UPDATE...POJORLIE
SHORT TERM...13
LONG TERM...10
AVIATION...BUNKERS




000
FXUS63 KUNR 311459
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
859 AM MDT MON AUG 31 2015

.UPDATE...
ISSUED AT 852 AM MDT MON AUG 31 2015

UPPER WAVE CONTINUES TO PUSH THROUGH THE NORTHERN PLAINS. RADAR
STILL INDICATES SHOWER ACTIVITY BEHIND THE COLD FRONT ACROSS
SOUTHWEST INTO CENTRAL SD. ADDED SOME ISOLATED SHOWERS THROUGH
THE DAY FOR ANY RAIN THAT MIGHT BE REACHING THE GROUND...ALTHOUGH
OBS STILL SHOW PRETTY DRY AIR SO IT MAY REMAIN VIRGA. INCREASED
CLOUD COVER TO REFLECT CURRENT TRENDS...BUT REST OF FORECAST LOOKS
ON TRACK FOR NOW.

&&

.SHORT TERM...TODAY THROUGH TUESDAY NIGHT
ISSUED AT 327 AM MDT MON AUG 31 2015

WATER VAPOR IMAGERY SHOWS STRONG UPPER WAVE CROSSING CNTRL TO ERN MT
INTO NRN WY. SURFACE ANALYSIS SHOWS LOW PRES ACROSS THE WRN/CNTRL
DAKOTAS AHEAD OF THE UPPER WAVE...WITH A COLD FRONT QUICKLY PUSHING
THRU ERN MT/CNTRL WY TOWARD THE CWA. TEMPS ACROSS THE CWA ARE IN THE
60S/70S...EVEN 80S ACROSS THE DOWNSLOPING N/NE BLKHLS. BEHIND THE
FRONT...OBS SHOWING TEMPS DROPPING INTO THE 50S WITH WINDS OF 15 TO
30 GUSTING TO 30 TO 40 MPH. RADAR SHOWS SHOWER ACTIVITY CROSSING WRN
SD...HOWEVER NEARLY ALL THE PRECIP IS VIRGA WITH LITTLE TO NO RAIN
REACHING THE GROUND. THE COLD FRONT WILL PUSH THROUGH NE WY TO WRN
SD IN THE NEXT 4/5 HOURS OR SO...AND CLEAR SCNTRL SD BY MID TO LATE
MORNING. HRRR SUGGESTS WINDS WILL GENERALLY BE 15 TO 25 MPH WITH
GUSTS TO 30 TO 40 MPH...BUT IS ALSO SHOWING STRONGER WINDS ACROSS
THE WRN SD PLAINS NORTH AND EAST OF THE BLKHLS. WIND ADVISORY
CRITERIA WINDS ARE EXPECTED...HOWEVER JUST FOR COUPLE HOURS OR SO
IMMEDIATELY AFTER THE FROPA. COULD SEE LINGERING SHRA ACTIVITY EARLY
THIS MORNING AS MODELS ARE HAVING A HARD TIME DECIDING HOW MUCH
PRECIP WILL REACH THE GROUND. WILL LEAN TOWARD A DRY FORECAST FOR
NOW CONSIDERING THE LATEST RADAR IMAGERY...BUT WILL REASSESS CLOSER
TO 12Z. OTHERWISE A DRY DAY IS EXPECTED WITH MUCH COOLER
TEMPERATURES AND CLEARING SKIES. HIGHS WILL REACH THE UPPER 70S TO
UPPER 80S. TEMPS TONIGHT WILL DROP INTO THE 50S TO LOWER 60S. RETURN
FLOW WILL SET UP BY MON NIGHT/TUE MRNG WITH WARMER TEMPS
EXPECTED. HIGHS WILL RETURN TO THE MID 80S TO MID 90S. DRY WEATHER
WILL CONTINUE TUE/TUE NIGHT WITH BROAD SWRLY FLOW ALOFT
PERSISTING.

.LONG TERM...WEDNESDAY THROUGH SUNDAY
ISSUED AT 327 AM MDT MON AUG 31 2015

THE UPPER TROUGH WILL REMAIN OVER THE NORTH AMERICAN PACIFIC
COAST THROUGH MOST OF THE WEEK...EVENTUALLY MOVING INLAND BY THE
WEEKEND AS ANOTHER IMPULSE DROPS INTO THE UPPER TROUGH FROM THE
NORTHWEST. THIS PATTERN WILL LEAD TO CONTINUED VERY WARM
TEMPERATURES OVER THE NORTHERN PLAINS BOTH WEDNESDAY AND THURSDAY.
FRIDAY AND SATURDAY WILL BE SLIGHTLY COOLER...WITH MUCH COOLER
TEMPS ON SUNDAY AND MONDAY BEHIND A RELATIVELY STRONG COLD FRONT
WHICH WILL PASS THROUGH THE AREA EARLY SUNDAY. DRY WEATHER IS
EXPECTED ON WEDNESDAY AND THURSDAY WITH A CHANCE OF THUNDERSTORMS
EACH DAY FROM FRIDAY THROUGH THE WEEKEND AS A SERIES OF UPPER
IMPULSES CROSS THE REGION AND COOLER AIR FLOWS IN AT THE SFC.

&&

.AVIATION...FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING
ISSUED AT 327 AM MDT MON AUG 31 2015

BREEZY NORTHWEST WINDS WILL FOLLOW A COLD FRONT THIS MORNING. VFR
CONDITIONS ARE EXPECTED TODAY AND TONIGHT.


&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
WY...NONE.
&&

$$

UPDATE...POJORLIE
SHORT TERM...13
LONG TERM...10
AVIATION...10



000
FXUS63 KUNR 311459
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
859 AM MDT MON AUG 31 2015

.UPDATE...
ISSUED AT 852 AM MDT MON AUG 31 2015

UPPER WAVE CONTINUES TO PUSH THROUGH THE NORTHERN PLAINS. RADAR
STILL INDICATES SHOWER ACTIVITY BEHIND THE COLD FRONT ACROSS
SOUTHWEST INTO CENTRAL SD. ADDED SOME ISOLATED SHOWERS THROUGH
THE DAY FOR ANY RAIN THAT MIGHT BE REACHING THE GROUND...ALTHOUGH
OBS STILL SHOW PRETTY DRY AIR SO IT MAY REMAIN VIRGA. INCREASED
CLOUD COVER TO REFLECT CURRENT TRENDS...BUT REST OF FORECAST LOOKS
ON TRACK FOR NOW.

&&

.SHORT TERM...TODAY THROUGH TUESDAY NIGHT
ISSUED AT 327 AM MDT MON AUG 31 2015

WATER VAPOR IMAGERY SHOWS STRONG UPPER WAVE CROSSING CNTRL TO ERN MT
INTO NRN WY. SURFACE ANALYSIS SHOWS LOW PRES ACROSS THE WRN/CNTRL
DAKOTAS AHEAD OF THE UPPER WAVE...WITH A COLD FRONT QUICKLY PUSHING
THRU ERN MT/CNTRL WY TOWARD THE CWA. TEMPS ACROSS THE CWA ARE IN THE
60S/70S...EVEN 80S ACROSS THE DOWNSLOPING N/NE BLKHLS. BEHIND THE
FRONT...OBS SHOWING TEMPS DROPPING INTO THE 50S WITH WINDS OF 15 TO
30 GUSTING TO 30 TO 40 MPH. RADAR SHOWS SHOWER ACTIVITY CROSSING WRN
SD...HOWEVER NEARLY ALL THE PRECIP IS VIRGA WITH LITTLE TO NO RAIN
REACHING THE GROUND. THE COLD FRONT WILL PUSH THROUGH NE WY TO WRN
SD IN THE NEXT 4/5 HOURS OR SO...AND CLEAR SCNTRL SD BY MID TO LATE
MORNING. HRRR SUGGESTS WINDS WILL GENERALLY BE 15 TO 25 MPH WITH
GUSTS TO 30 TO 40 MPH...BUT IS ALSO SHOWING STRONGER WINDS ACROSS
THE WRN SD PLAINS NORTH AND EAST OF THE BLKHLS. WIND ADVISORY
CRITERIA WINDS ARE EXPECTED...HOWEVER JUST FOR COUPLE HOURS OR SO
IMMEDIATELY AFTER THE FROPA. COULD SEE LINGERING SHRA ACTIVITY EARLY
THIS MORNING AS MODELS ARE HAVING A HARD TIME DECIDING HOW MUCH
PRECIP WILL REACH THE GROUND. WILL LEAN TOWARD A DRY FORECAST FOR
NOW CONSIDERING THE LATEST RADAR IMAGERY...BUT WILL REASSESS CLOSER
TO 12Z. OTHERWISE A DRY DAY IS EXPECTED WITH MUCH COOLER
TEMPERATURES AND CLEARING SKIES. HIGHS WILL REACH THE UPPER 70S TO
UPPER 80S. TEMPS TONIGHT WILL DROP INTO THE 50S TO LOWER 60S. RETURN
FLOW WILL SET UP BY MON NIGHT/TUE MRNG WITH WARMER TEMPS
EXPECTED. HIGHS WILL RETURN TO THE MID 80S TO MID 90S. DRY WEATHER
WILL CONTINUE TUE/TUE NIGHT WITH BROAD SWRLY FLOW ALOFT
PERSISTING.

.LONG TERM...WEDNESDAY THROUGH SUNDAY
ISSUED AT 327 AM MDT MON AUG 31 2015

THE UPPER TROUGH WILL REMAIN OVER THE NORTH AMERICAN PACIFIC
COAST THROUGH MOST OF THE WEEK...EVENTUALLY MOVING INLAND BY THE
WEEKEND AS ANOTHER IMPULSE DROPS INTO THE UPPER TROUGH FROM THE
NORTHWEST. THIS PATTERN WILL LEAD TO CONTINUED VERY WARM
TEMPERATURES OVER THE NORTHERN PLAINS BOTH WEDNESDAY AND THURSDAY.
FRIDAY AND SATURDAY WILL BE SLIGHTLY COOLER...WITH MUCH COOLER
TEMPS ON SUNDAY AND MONDAY BEHIND A RELATIVELY STRONG COLD FRONT
WHICH WILL PASS THROUGH THE AREA EARLY SUNDAY. DRY WEATHER IS
EXPECTED ON WEDNESDAY AND THURSDAY WITH A CHANCE OF THUNDERSTORMS
EACH DAY FROM FRIDAY THROUGH THE WEEKEND AS A SERIES OF UPPER
IMPULSES CROSS THE REGION AND COOLER AIR FLOWS IN AT THE SFC.

&&

.AVIATION...FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING
ISSUED AT 327 AM MDT MON AUG 31 2015

BREEZY NORTHWEST WINDS WILL FOLLOW A COLD FRONT THIS MORNING. VFR
CONDITIONS ARE EXPECTED TODAY AND TONIGHT.


&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
WY...NONE.
&&

$$

UPDATE...POJORLIE
SHORT TERM...13
LONG TERM...10
AVIATION...10



000
FXUS63 KUNR 311459
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
859 AM MDT MON AUG 31 2015

.UPDATE...
ISSUED AT 852 AM MDT MON AUG 31 2015

UPPER WAVE CONTINUES TO PUSH THROUGH THE NORTHERN PLAINS. RADAR
STILL INDICATES SHOWER ACTIVITY BEHIND THE COLD FRONT ACROSS
SOUTHWEST INTO CENTRAL SD. ADDED SOME ISOLATED SHOWERS THROUGH
THE DAY FOR ANY RAIN THAT MIGHT BE REACHING THE GROUND...ALTHOUGH
OBS STILL SHOW PRETTY DRY AIR SO IT MAY REMAIN VIRGA. INCREASED
CLOUD COVER TO REFLECT CURRENT TRENDS...BUT REST OF FORECAST LOOKS
ON TRACK FOR NOW.

&&

.SHORT TERM...TODAY THROUGH TUESDAY NIGHT
ISSUED AT 327 AM MDT MON AUG 31 2015

WATER VAPOR IMAGERY SHOWS STRONG UPPER WAVE CROSSING CNTRL TO ERN MT
INTO NRN WY. SURFACE ANALYSIS SHOWS LOW PRES ACROSS THE WRN/CNTRL
DAKOTAS AHEAD OF THE UPPER WAVE...WITH A COLD FRONT QUICKLY PUSHING
THRU ERN MT/CNTRL WY TOWARD THE CWA. TEMPS ACROSS THE CWA ARE IN THE
60S/70S...EVEN 80S ACROSS THE DOWNSLOPING N/NE BLKHLS. BEHIND THE
FRONT...OBS SHOWING TEMPS DROPPING INTO THE 50S WITH WINDS OF 15 TO
30 GUSTING TO 30 TO 40 MPH. RADAR SHOWS SHOWER ACTIVITY CROSSING WRN
SD...HOWEVER NEARLY ALL THE PRECIP IS VIRGA WITH LITTLE TO NO RAIN
REACHING THE GROUND. THE COLD FRONT WILL PUSH THROUGH NE WY TO WRN
SD IN THE NEXT 4/5 HOURS OR SO...AND CLEAR SCNTRL SD BY MID TO LATE
MORNING. HRRR SUGGESTS WINDS WILL GENERALLY BE 15 TO 25 MPH WITH
GUSTS TO 30 TO 40 MPH...BUT IS ALSO SHOWING STRONGER WINDS ACROSS
THE WRN SD PLAINS NORTH AND EAST OF THE BLKHLS. WIND ADVISORY
CRITERIA WINDS ARE EXPECTED...HOWEVER JUST FOR COUPLE HOURS OR SO
IMMEDIATELY AFTER THE FROPA. COULD SEE LINGERING SHRA ACTIVITY EARLY
THIS MORNING AS MODELS ARE HAVING A HARD TIME DECIDING HOW MUCH
PRECIP WILL REACH THE GROUND. WILL LEAN TOWARD A DRY FORECAST FOR
NOW CONSIDERING THE LATEST RADAR IMAGERY...BUT WILL REASSESS CLOSER
TO 12Z. OTHERWISE A DRY DAY IS EXPECTED WITH MUCH COOLER
TEMPERATURES AND CLEARING SKIES. HIGHS WILL REACH THE UPPER 70S TO
UPPER 80S. TEMPS TONIGHT WILL DROP INTO THE 50S TO LOWER 60S. RETURN
FLOW WILL SET UP BY MON NIGHT/TUE MRNG WITH WARMER TEMPS
EXPECTED. HIGHS WILL RETURN TO THE MID 80S TO MID 90S. DRY WEATHER
WILL CONTINUE TUE/TUE NIGHT WITH BROAD SWRLY FLOW ALOFT
PERSISTING.

.LONG TERM...WEDNESDAY THROUGH SUNDAY
ISSUED AT 327 AM MDT MON AUG 31 2015

THE UPPER TROUGH WILL REMAIN OVER THE NORTH AMERICAN PACIFIC
COAST THROUGH MOST OF THE WEEK...EVENTUALLY MOVING INLAND BY THE
WEEKEND AS ANOTHER IMPULSE DROPS INTO THE UPPER TROUGH FROM THE
NORTHWEST. THIS PATTERN WILL LEAD TO CONTINUED VERY WARM
TEMPERATURES OVER THE NORTHERN PLAINS BOTH WEDNESDAY AND THURSDAY.
FRIDAY AND SATURDAY WILL BE SLIGHTLY COOLER...WITH MUCH COOLER
TEMPS ON SUNDAY AND MONDAY BEHIND A RELATIVELY STRONG COLD FRONT
WHICH WILL PASS THROUGH THE AREA EARLY SUNDAY. DRY WEATHER IS
EXPECTED ON WEDNESDAY AND THURSDAY WITH A CHANCE OF THUNDERSTORMS
EACH DAY FROM FRIDAY THROUGH THE WEEKEND AS A SERIES OF UPPER
IMPULSES CROSS THE REGION AND COOLER AIR FLOWS IN AT THE SFC.

&&

.AVIATION...FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING
ISSUED AT 327 AM MDT MON AUG 31 2015

BREEZY NORTHWEST WINDS WILL FOLLOW A COLD FRONT THIS MORNING. VFR
CONDITIONS ARE EXPECTED TODAY AND TONIGHT.


&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
WY...NONE.
&&

$$

UPDATE...POJORLIE
SHORT TERM...13
LONG TERM...10
AVIATION...10



000
FXUS63 KUNR 311459
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
859 AM MDT MON AUG 31 2015

.UPDATE...
ISSUED AT 852 AM MDT MON AUG 31 2015

UPPER WAVE CONTINUES TO PUSH THROUGH THE NORTHERN PLAINS. RADAR
STILL INDICATES SHOWER ACTIVITY BEHIND THE COLD FRONT ACROSS
SOUTHWEST INTO CENTRAL SD. ADDED SOME ISOLATED SHOWERS THROUGH
THE DAY FOR ANY RAIN THAT MIGHT BE REACHING THE GROUND...ALTHOUGH
OBS STILL SHOW PRETTY DRY AIR SO IT MAY REMAIN VIRGA. INCREASED
CLOUD COVER TO REFLECT CURRENT TRENDS...BUT REST OF FORECAST LOOKS
ON TRACK FOR NOW.

&&

.SHORT TERM...TODAY THROUGH TUESDAY NIGHT
ISSUED AT 327 AM MDT MON AUG 31 2015

WATER VAPOR IMAGERY SHOWS STRONG UPPER WAVE CROSSING CNTRL TO ERN MT
INTO NRN WY. SURFACE ANALYSIS SHOWS LOW PRES ACROSS THE WRN/CNTRL
DAKOTAS AHEAD OF THE UPPER WAVE...WITH A COLD FRONT QUICKLY PUSHING
THRU ERN MT/CNTRL WY TOWARD THE CWA. TEMPS ACROSS THE CWA ARE IN THE
60S/70S...EVEN 80S ACROSS THE DOWNSLOPING N/NE BLKHLS. BEHIND THE
FRONT...OBS SHOWING TEMPS DROPPING INTO THE 50S WITH WINDS OF 15 TO
30 GUSTING TO 30 TO 40 MPH. RADAR SHOWS SHOWER ACTIVITY CROSSING WRN
SD...HOWEVER NEARLY ALL THE PRECIP IS VIRGA WITH LITTLE TO NO RAIN
REACHING THE GROUND. THE COLD FRONT WILL PUSH THROUGH NE WY TO WRN
SD IN THE NEXT 4/5 HOURS OR SO...AND CLEAR SCNTRL SD BY MID TO LATE
MORNING. HRRR SUGGESTS WINDS WILL GENERALLY BE 15 TO 25 MPH WITH
GUSTS TO 30 TO 40 MPH...BUT IS ALSO SHOWING STRONGER WINDS ACROSS
THE WRN SD PLAINS NORTH AND EAST OF THE BLKHLS. WIND ADVISORY
CRITERIA WINDS ARE EXPECTED...HOWEVER JUST FOR COUPLE HOURS OR SO
IMMEDIATELY AFTER THE FROPA. COULD SEE LINGERING SHRA ACTIVITY EARLY
THIS MORNING AS MODELS ARE HAVING A HARD TIME DECIDING HOW MUCH
PRECIP WILL REACH THE GROUND. WILL LEAN TOWARD A DRY FORECAST FOR
NOW CONSIDERING THE LATEST RADAR IMAGERY...BUT WILL REASSESS CLOSER
TO 12Z. OTHERWISE A DRY DAY IS EXPECTED WITH MUCH COOLER
TEMPERATURES AND CLEARING SKIES. HIGHS WILL REACH THE UPPER 70S TO
UPPER 80S. TEMPS TONIGHT WILL DROP INTO THE 50S TO LOWER 60S. RETURN
FLOW WILL SET UP BY MON NIGHT/TUE MRNG WITH WARMER TEMPS
EXPECTED. HIGHS WILL RETURN TO THE MID 80S TO MID 90S. DRY WEATHER
WILL CONTINUE TUE/TUE NIGHT WITH BROAD SWRLY FLOW ALOFT
PERSISTING.

.LONG TERM...WEDNESDAY THROUGH SUNDAY
ISSUED AT 327 AM MDT MON AUG 31 2015

THE UPPER TROUGH WILL REMAIN OVER THE NORTH AMERICAN PACIFIC
COAST THROUGH MOST OF THE WEEK...EVENTUALLY MOVING INLAND BY THE
WEEKEND AS ANOTHER IMPULSE DROPS INTO THE UPPER TROUGH FROM THE
NORTHWEST. THIS PATTERN WILL LEAD TO CONTINUED VERY WARM
TEMPERATURES OVER THE NORTHERN PLAINS BOTH WEDNESDAY AND THURSDAY.
FRIDAY AND SATURDAY WILL BE SLIGHTLY COOLER...WITH MUCH COOLER
TEMPS ON SUNDAY AND MONDAY BEHIND A RELATIVELY STRONG COLD FRONT
WHICH WILL PASS THROUGH THE AREA EARLY SUNDAY. DRY WEATHER IS
EXPECTED ON WEDNESDAY AND THURSDAY WITH A CHANCE OF THUNDERSTORMS
EACH DAY FROM FRIDAY THROUGH THE WEEKEND AS A SERIES OF UPPER
IMPULSES CROSS THE REGION AND COOLER AIR FLOWS IN AT THE SFC.

&&

.AVIATION...FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING
ISSUED AT 327 AM MDT MON AUG 31 2015

BREEZY NORTHWEST WINDS WILL FOLLOW A COLD FRONT THIS MORNING. VFR
CONDITIONS ARE EXPECTED TODAY AND TONIGHT.


&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
WY...NONE.
&&

$$

UPDATE...POJORLIE
SHORT TERM...13
LONG TERM...10
AVIATION...10



000
FXUS65 KCYS 311032
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
432 AM MDT MON AUG 31 2015

.SHORT TERM...(TODAY THROUGH WEDNESDAY NIGHT)
ISSUED AT 431 AM MDT MON AUG 31 2015

SCATTERED SHOWERS WILL CONTINUE EARLY THIS MORNING AHEAD OF A
SHORTWAVE MOVING UP FROM THE SOUTHWEST WITHIN THE RIGHT ENTRANCE
REGION OF AN UPPER LEVEL JET MAX. A FEW LIGHTNING STRIKES HAVE BEEN
OBSERVED OVER NORTHWEST COLORADO THE PAST FEW HOURS...SO CANT
RULE OUT AN ISOLATED STORM OVER THE SOUTHERN WYOMING MOUNTAINS AS
WELL. THE COLD FRONT LOOKS TO BE DRAPED ACROSS NORTHERN WYOMING
ACCORDING TO 4AM SFC OBS AND SHOULD BEGIN TO MOVE ACROSS OUR
EASTERN COUNTIES AROUND SUNRISE. AHEAD OF THE FRONT...SOUTHWEST
WINDS HAVE BECOME QUITE BREEZY OVERNIGHT WITH GUSTS ON AVERAGE OF
25 TO 35 MPH...WITH A FEW SPOTS ALONG AND WEST OF THE LARAMIE
RANGE REPORTING HIGHER SPEEDS. WILL SEE THESE WINDS PERSIST
THROUGH THE MORNING AS THE FRONT SLIDES SOUTH ACROSS THE
PLAINS...AND WINDS BEHIND THE FRONT WILL VEER TO THE NORTH
REMAINING GUSTY AT TIMES.

TEMPS WILL BE COOLER TODAY IN THE POST FRONTAL AIRMASS WITH
READINGS EXPECTED TO REMAIN IN THE 70S AND 80S. AS THE SFC HIGH
DROPS INTO THE CENTRAL PLAINS...SFC WINDS WILL VEER FURTHER TO A
SOUTHEASTERLY UPSLOPE COMPONENT THROUGH THE AFTERNOON. UPPER LEVEL
FLOW WILL REMAIN OUT OF THE SOUTHWEST WITH A CONTINUED STREAM OF
SUBTROPICAL MOISTURE...SO MAINTAINED A CHANCE FOR SHOWERS AND
TSTMS THIS AFTERNOON OVER THE MOUNTAINS BUT ALSO EXPANDED SLIGHT
CHANCES EASTWARD WITHIN THE UPSLOPE REGIME...ALTHO COVERAGE IN
THIS AREA WILL REMAIN VERY ISOLATED. ALTHO LLVL MOISTURE WILL BE
HIGHER THAN YESTERDAY...GUSTY WINDS ARE STILL A GOOD BET WITH THIS
ACTIVITY.

TUESDAY WILL BE WARMER AS THE COLDER AIRMASS RETREATS TO THE EAST
AND ANOTHER SHORTWAVE EMBEDDED IN SOUTHWEST FLOW LOOKS TO MOVE
OVERHEAD BRINGING ADDITIONAL CHANCES FOR AFTERNOON SHOWERS AND
TSTMS BUT MAINLY TO THE MOUNTAINS. A STRONG UPPER LOW WILL DIG
INTO THE PAC NW ON WEDNESDAY AND SHOULD DEEPEN THE LEESIDE
PRESSURE TROUGH THRU WEDNESDAY MORNING/AFTERNOON. SFC WINDS WILL
INCREASE IN RESPONSE WITH GUSTS OF 30 TO 35 MPH POSSIBLE THRU THE
AFTERNOON OUT WEST AS 700-500 MBS WILL RAMP UP TO 25 TO 35 KTS. A
SOMEWHAT DRIER AIRMASS WILL MOVE IN FOR WEDNESDAY WHILE TEMPS
CONTINUE TO WARM UNDER AMPLIFIED SOUTHWEST FLOW. PRECIP CHANCES
WILL BE LESS OVERALL BUT CANT RULE OUT A TSTM OR TWO OVER THE
MOUNTAINS.

.LONG TERM...(THURSDAY THROUGH SUNDAY)
ISSUED AT 431 AM MDT MON AUG 31 2015

THURSDAY...DRY AND MILD DAY UNDER SOUTHWEST FLOW ALOFT AND WITH
LIMITED LOW AND MID LEVEL MOISTURE TO FUEL THUNDERSTORMS.

FRIDAY...FLOW ALOFT REMAINS SOUTHWEST. HOWEVER...WITH AN INCREASE IN
LOW AND MID LEVEL MOISTURE AND LOW LEVEL UPSLOPE WINDS...EXPECT
ISOLATED LATE DAY SHOWERS AND THUNDERSTORMS MAINLY ALONG AND EAST OF
THE LARAMIE RANGE.

SATURDAY...NEXT MORE POTENT SHORTWAVE TROUGH ALOFT MOVES ACROSS
MONTANA. EXPECT ISOLATED LATE DAY THUNDERSTORMS TO DEVELOP IN OUR
COUNTIES ALONG A CONVERGENCE BOUNDARY.

SUNDAY...MOSTLY DRY DAY IN THE WAKE OF A COLD FRONT AS DRIER AND
MORE STABLE AIRMASS MOVES IN.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 431 AM MDT MON AUG 31 2015

VFR PREVAILS. ISOLATED TO SCATTERED AFTERNOON AND EVENING
THUNDERSTORMS FROM CHEYENNE WEST WITH LOCALIZED MVFR AND GUSTY AND
ERRATIC WIND.|

&&

.FIRE WEATHER...
ISSUED AT 431 AM MDT MON AUG 31 2015

WIDELY SCATTERED LIGHT RAIN SHOWERS WILL CONTINUE TO MOVE NORTHEAST
ACROSS THE DISTRICT THIS MORNING. BREEZY SOUTHWEST WINDS OF 25 TO 35
MPH WITH A FEW HIGHER GUSTS WILL ALSO PERSIST AHEAD OF A COLD FRONT
THAT WILL DROP SOUTH ACROSS THE EASTERN PLAINS AFTER SUNRISE.
WINDS ACROSS THE PLAINS BEHIND THE FRONT WILL SWITCH TO THE NORTH
WITH GUSTS TO 25 MPH...THEN WILL VEER TO THE SOUTHEAST THROUGH THE
AFTERNOON. A FEW SHOWERS AND TSTORMS WILL RETURN TO THE MOUNTAINS AND
NEARBY EASTERN PLAINS THIS AFTERNOON AS ENERGETIC SUBTROPICAL FLOW
REMAINS OVERHEAD. COOLER TEMPS TODAY WILL BE SHORT-LIVED WITH VERY
WARM...DRY AND BREEZY CONDITIONS LOOKING TO RETURN TO SOUTHEAST
WYOMING THROUGH THE END OF THE WEEK.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&

$$

SHORT TERM...RJM
LONG TERM...RUBIN
AVIATION...RUBIN
FIRE WEATHER...RJM



000
FXUS65 KCYS 311032
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
432 AM MDT MON AUG 31 2015

.SHORT TERM...(TODAY THROUGH WEDNESDAY NIGHT)
ISSUED AT 431 AM MDT MON AUG 31 2015

SCATTERED SHOWERS WILL CONTINUE EARLY THIS MORNING AHEAD OF A
SHORTWAVE MOVING UP FROM THE SOUTHWEST WITHIN THE RIGHT ENTRANCE
REGION OF AN UPPER LEVEL JET MAX. A FEW LIGHTNING STRIKES HAVE BEEN
OBSERVED OVER NORTHWEST COLORADO THE PAST FEW HOURS...SO CANT
RULE OUT AN ISOLATED STORM OVER THE SOUTHERN WYOMING MOUNTAINS AS
WELL. THE COLD FRONT LOOKS TO BE DRAPED ACROSS NORTHERN WYOMING
ACCORDING TO 4AM SFC OBS AND SHOULD BEGIN TO MOVE ACROSS OUR
EASTERN COUNTIES AROUND SUNRISE. AHEAD OF THE FRONT...SOUTHWEST
WINDS HAVE BECOME QUITE BREEZY OVERNIGHT WITH GUSTS ON AVERAGE OF
25 TO 35 MPH...WITH A FEW SPOTS ALONG AND WEST OF THE LARAMIE
RANGE REPORTING HIGHER SPEEDS. WILL SEE THESE WINDS PERSIST
THROUGH THE MORNING AS THE FRONT SLIDES SOUTH ACROSS THE
PLAINS...AND WINDS BEHIND THE FRONT WILL VEER TO THE NORTH
REMAINING GUSTY AT TIMES.

TEMPS WILL BE COOLER TODAY IN THE POST FRONTAL AIRMASS WITH
READINGS EXPECTED TO REMAIN IN THE 70S AND 80S. AS THE SFC HIGH
DROPS INTO THE CENTRAL PLAINS...SFC WINDS WILL VEER FURTHER TO A
SOUTHEASTERLY UPSLOPE COMPONENT THROUGH THE AFTERNOON. UPPER LEVEL
FLOW WILL REMAIN OUT OF THE SOUTHWEST WITH A CONTINUED STREAM OF
SUBTROPICAL MOISTURE...SO MAINTAINED A CHANCE FOR SHOWERS AND
TSTMS THIS AFTERNOON OVER THE MOUNTAINS BUT ALSO EXPANDED SLIGHT
CHANCES EASTWARD WITHIN THE UPSLOPE REGIME...ALTHO COVERAGE IN
THIS AREA WILL REMAIN VERY ISOLATED. ALTHO LLVL MOISTURE WILL BE
HIGHER THAN YESTERDAY...GUSTY WINDS ARE STILL A GOOD BET WITH THIS
ACTIVITY.

TUESDAY WILL BE WARMER AS THE COLDER AIRMASS RETREATS TO THE EAST
AND ANOTHER SHORTWAVE EMBEDDED IN SOUTHWEST FLOW LOOKS TO MOVE
OVERHEAD BRINGING ADDITIONAL CHANCES FOR AFTERNOON SHOWERS AND
TSTMS BUT MAINLY TO THE MOUNTAINS. A STRONG UPPER LOW WILL DIG
INTO THE PAC NW ON WEDNESDAY AND SHOULD DEEPEN THE LEESIDE
PRESSURE TROUGH THRU WEDNESDAY MORNING/AFTERNOON. SFC WINDS WILL
INCREASE IN RESPONSE WITH GUSTS OF 30 TO 35 MPH POSSIBLE THRU THE
AFTERNOON OUT WEST AS 700-500 MBS WILL RAMP UP TO 25 TO 35 KTS. A
SOMEWHAT DRIER AIRMASS WILL MOVE IN FOR WEDNESDAY WHILE TEMPS
CONTINUE TO WARM UNDER AMPLIFIED SOUTHWEST FLOW. PRECIP CHANCES
WILL BE LESS OVERALL BUT CANT RULE OUT A TSTM OR TWO OVER THE
MOUNTAINS.

.LONG TERM...(THURSDAY THROUGH SUNDAY)
ISSUED AT 431 AM MDT MON AUG 31 2015

THURSDAY...DRY AND MILD DAY UNDER SOUTHWEST FLOW ALOFT AND WITH
LIMITED LOW AND MID LEVEL MOISTURE TO FUEL THUNDERSTORMS.

FRIDAY...FLOW ALOFT REMAINS SOUTHWEST. HOWEVER...WITH AN INCREASE IN
LOW AND MID LEVEL MOISTURE AND LOW LEVEL UPSLOPE WINDS...EXPECT
ISOLATED LATE DAY SHOWERS AND THUNDERSTORMS MAINLY ALONG AND EAST OF
THE LARAMIE RANGE.

SATURDAY...NEXT MORE POTENT SHORTWAVE TROUGH ALOFT MOVES ACROSS
MONTANA. EXPECT ISOLATED LATE DAY THUNDERSTORMS TO DEVELOP IN OUR
COUNTIES ALONG A CONVERGENCE BOUNDARY.

SUNDAY...MOSTLY DRY DAY IN THE WAKE OF A COLD FRONT AS DRIER AND
MORE STABLE AIRMASS MOVES IN.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 431 AM MDT MON AUG 31 2015

VFR PREVAILS. ISOLATED TO SCATTERED AFTERNOON AND EVENING
THUNDERSTORMS FROM CHEYENNE WEST WITH LOCALIZED MVFR AND GUSTY AND
ERRATIC WIND.|

&&

.FIRE WEATHER...
ISSUED AT 431 AM MDT MON AUG 31 2015

WIDELY SCATTERED LIGHT RAIN SHOWERS WILL CONTINUE TO MOVE NORTHEAST
ACROSS THE DISTRICT THIS MORNING. BREEZY SOUTHWEST WINDS OF 25 TO 35
MPH WITH A FEW HIGHER GUSTS WILL ALSO PERSIST AHEAD OF A COLD FRONT
THAT WILL DROP SOUTH ACROSS THE EASTERN PLAINS AFTER SUNRISE.
WINDS ACROSS THE PLAINS BEHIND THE FRONT WILL SWITCH TO THE NORTH
WITH GUSTS TO 25 MPH...THEN WILL VEER TO THE SOUTHEAST THROUGH THE
AFTERNOON. A FEW SHOWERS AND TSTORMS WILL RETURN TO THE MOUNTAINS AND
NEARBY EASTERN PLAINS THIS AFTERNOON AS ENERGETIC SUBTROPICAL FLOW
REMAINS OVERHEAD. COOLER TEMPS TODAY WILL BE SHORT-LIVED WITH VERY
WARM...DRY AND BREEZY CONDITIONS LOOKING TO RETURN TO SOUTHEAST
WYOMING THROUGH THE END OF THE WEEK.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&

$$

SHORT TERM...RJM
LONG TERM...RUBIN
AVIATION...RUBIN
FIRE WEATHER...RJM



000
FXUS65 KCYS 311032
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
432 AM MDT MON AUG 31 2015

.SHORT TERM...(TODAY THROUGH WEDNESDAY NIGHT)
ISSUED AT 431 AM MDT MON AUG 31 2015

SCATTERED SHOWERS WILL CONTINUE EARLY THIS MORNING AHEAD OF A
SHORTWAVE MOVING UP FROM THE SOUTHWEST WITHIN THE RIGHT ENTRANCE
REGION OF AN UPPER LEVEL JET MAX. A FEW LIGHTNING STRIKES HAVE BEEN
OBSERVED OVER NORTHWEST COLORADO THE PAST FEW HOURS...SO CANT
RULE OUT AN ISOLATED STORM OVER THE SOUTHERN WYOMING MOUNTAINS AS
WELL. THE COLD FRONT LOOKS TO BE DRAPED ACROSS NORTHERN WYOMING
ACCORDING TO 4AM SFC OBS AND SHOULD BEGIN TO MOVE ACROSS OUR
EASTERN COUNTIES AROUND SUNRISE. AHEAD OF THE FRONT...SOUTHWEST
WINDS HAVE BECOME QUITE BREEZY OVERNIGHT WITH GUSTS ON AVERAGE OF
25 TO 35 MPH...WITH A FEW SPOTS ALONG AND WEST OF THE LARAMIE
RANGE REPORTING HIGHER SPEEDS. WILL SEE THESE WINDS PERSIST
THROUGH THE MORNING AS THE FRONT SLIDES SOUTH ACROSS THE
PLAINS...AND WINDS BEHIND THE FRONT WILL VEER TO THE NORTH
REMAINING GUSTY AT TIMES.

TEMPS WILL BE COOLER TODAY IN THE POST FRONTAL AIRMASS WITH
READINGS EXPECTED TO REMAIN IN THE 70S AND 80S. AS THE SFC HIGH
DROPS INTO THE CENTRAL PLAINS...SFC WINDS WILL VEER FURTHER TO A
SOUTHEASTERLY UPSLOPE COMPONENT THROUGH THE AFTERNOON. UPPER LEVEL
FLOW WILL REMAIN OUT OF THE SOUTHWEST WITH A CONTINUED STREAM OF
SUBTROPICAL MOISTURE...SO MAINTAINED A CHANCE FOR SHOWERS AND
TSTMS THIS AFTERNOON OVER THE MOUNTAINS BUT ALSO EXPANDED SLIGHT
CHANCES EASTWARD WITHIN THE UPSLOPE REGIME...ALTHO COVERAGE IN
THIS AREA WILL REMAIN VERY ISOLATED. ALTHO LLVL MOISTURE WILL BE
HIGHER THAN YESTERDAY...GUSTY WINDS ARE STILL A GOOD BET WITH THIS
ACTIVITY.

TUESDAY WILL BE WARMER AS THE COLDER AIRMASS RETREATS TO THE EAST
AND ANOTHER SHORTWAVE EMBEDDED IN SOUTHWEST FLOW LOOKS TO MOVE
OVERHEAD BRINGING ADDITIONAL CHANCES FOR AFTERNOON SHOWERS AND
TSTMS BUT MAINLY TO THE MOUNTAINS. A STRONG UPPER LOW WILL DIG
INTO THE PAC NW ON WEDNESDAY AND SHOULD DEEPEN THE LEESIDE
PRESSURE TROUGH THRU WEDNESDAY MORNING/AFTERNOON. SFC WINDS WILL
INCREASE IN RESPONSE WITH GUSTS OF 30 TO 35 MPH POSSIBLE THRU THE
AFTERNOON OUT WEST AS 700-500 MBS WILL RAMP UP TO 25 TO 35 KTS. A
SOMEWHAT DRIER AIRMASS WILL MOVE IN FOR WEDNESDAY WHILE TEMPS
CONTINUE TO WARM UNDER AMPLIFIED SOUTHWEST FLOW. PRECIP CHANCES
WILL BE LESS OVERALL BUT CANT RULE OUT A TSTM OR TWO OVER THE
MOUNTAINS.

.LONG TERM...(THURSDAY THROUGH SUNDAY)
ISSUED AT 431 AM MDT MON AUG 31 2015

THURSDAY...DRY AND MILD DAY UNDER SOUTHWEST FLOW ALOFT AND WITH
LIMITED LOW AND MID LEVEL MOISTURE TO FUEL THUNDERSTORMS.

FRIDAY...FLOW ALOFT REMAINS SOUTHWEST. HOWEVER...WITH AN INCREASE IN
LOW AND MID LEVEL MOISTURE AND LOW LEVEL UPSLOPE WINDS...EXPECT
ISOLATED LATE DAY SHOWERS AND THUNDERSTORMS MAINLY ALONG AND EAST OF
THE LARAMIE RANGE.

SATURDAY...NEXT MORE POTENT SHORTWAVE TROUGH ALOFT MOVES ACROSS
MONTANA. EXPECT ISOLATED LATE DAY THUNDERSTORMS TO DEVELOP IN OUR
COUNTIES ALONG A CONVERGENCE BOUNDARY.

SUNDAY...MOSTLY DRY DAY IN THE WAKE OF A COLD FRONT AS DRIER AND
MORE STABLE AIRMASS MOVES IN.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 431 AM MDT MON AUG 31 2015

VFR PREVAILS. ISOLATED TO SCATTERED AFTERNOON AND EVENING
THUNDERSTORMS FROM CHEYENNE WEST WITH LOCALIZED MVFR AND GUSTY AND
ERRATIC WIND.|

&&

.FIRE WEATHER...
ISSUED AT 431 AM MDT MON AUG 31 2015

WIDELY SCATTERED LIGHT RAIN SHOWERS WILL CONTINUE TO MOVE NORTHEAST
ACROSS THE DISTRICT THIS MORNING. BREEZY SOUTHWEST WINDS OF 25 TO 35
MPH WITH A FEW HIGHER GUSTS WILL ALSO PERSIST AHEAD OF A COLD FRONT
THAT WILL DROP SOUTH ACROSS THE EASTERN PLAINS AFTER SUNRISE.
WINDS ACROSS THE PLAINS BEHIND THE FRONT WILL SWITCH TO THE NORTH
WITH GUSTS TO 25 MPH...THEN WILL VEER TO THE SOUTHEAST THROUGH THE
AFTERNOON. A FEW SHOWERS AND TSTORMS WILL RETURN TO THE MOUNTAINS AND
NEARBY EASTERN PLAINS THIS AFTERNOON AS ENERGETIC SUBTROPICAL FLOW
REMAINS OVERHEAD. COOLER TEMPS TODAY WILL BE SHORT-LIVED WITH VERY
WARM...DRY AND BREEZY CONDITIONS LOOKING TO RETURN TO SOUTHEAST
WYOMING THROUGH THE END OF THE WEEK.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&

$$

SHORT TERM...RJM
LONG TERM...RUBIN
AVIATION...RUBIN
FIRE WEATHER...RJM



000
FXUS65 KCYS 311032
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
432 AM MDT MON AUG 31 2015

.SHORT TERM...(TODAY THROUGH WEDNESDAY NIGHT)
ISSUED AT 431 AM MDT MON AUG 31 2015

SCATTERED SHOWERS WILL CONTINUE EARLY THIS MORNING AHEAD OF A
SHORTWAVE MOVING UP FROM THE SOUTHWEST WITHIN THE RIGHT ENTRANCE
REGION OF AN UPPER LEVEL JET MAX. A FEW LIGHTNING STRIKES HAVE BEEN
OBSERVED OVER NORTHWEST COLORADO THE PAST FEW HOURS...SO CANT
RULE OUT AN ISOLATED STORM OVER THE SOUTHERN WYOMING MOUNTAINS AS
WELL. THE COLD FRONT LOOKS TO BE DRAPED ACROSS NORTHERN WYOMING
ACCORDING TO 4AM SFC OBS AND SHOULD BEGIN TO MOVE ACROSS OUR
EASTERN COUNTIES AROUND SUNRISE. AHEAD OF THE FRONT...SOUTHWEST
WINDS HAVE BECOME QUITE BREEZY OVERNIGHT WITH GUSTS ON AVERAGE OF
25 TO 35 MPH...WITH A FEW SPOTS ALONG AND WEST OF THE LARAMIE
RANGE REPORTING HIGHER SPEEDS. WILL SEE THESE WINDS PERSIST
THROUGH THE MORNING AS THE FRONT SLIDES SOUTH ACROSS THE
PLAINS...AND WINDS BEHIND THE FRONT WILL VEER TO THE NORTH
REMAINING GUSTY AT TIMES.

TEMPS WILL BE COOLER TODAY IN THE POST FRONTAL AIRMASS WITH
READINGS EXPECTED TO REMAIN IN THE 70S AND 80S. AS THE SFC HIGH
DROPS INTO THE CENTRAL PLAINS...SFC WINDS WILL VEER FURTHER TO A
SOUTHEASTERLY UPSLOPE COMPONENT THROUGH THE AFTERNOON. UPPER LEVEL
FLOW WILL REMAIN OUT OF THE SOUTHWEST WITH A CONTINUED STREAM OF
SUBTROPICAL MOISTURE...SO MAINTAINED A CHANCE FOR SHOWERS AND
TSTMS THIS AFTERNOON OVER THE MOUNTAINS BUT ALSO EXPANDED SLIGHT
CHANCES EASTWARD WITHIN THE UPSLOPE REGIME...ALTHO COVERAGE IN
THIS AREA WILL REMAIN VERY ISOLATED. ALTHO LLVL MOISTURE WILL BE
HIGHER THAN YESTERDAY...GUSTY WINDS ARE STILL A GOOD BET WITH THIS
ACTIVITY.

TUESDAY WILL BE WARMER AS THE COLDER AIRMASS RETREATS TO THE EAST
AND ANOTHER SHORTWAVE EMBEDDED IN SOUTHWEST FLOW LOOKS TO MOVE
OVERHEAD BRINGING ADDITIONAL CHANCES FOR AFTERNOON SHOWERS AND
TSTMS BUT MAINLY TO THE MOUNTAINS. A STRONG UPPER LOW WILL DIG
INTO THE PAC NW ON WEDNESDAY AND SHOULD DEEPEN THE LEESIDE
PRESSURE TROUGH THRU WEDNESDAY MORNING/AFTERNOON. SFC WINDS WILL
INCREASE IN RESPONSE WITH GUSTS OF 30 TO 35 MPH POSSIBLE THRU THE
AFTERNOON OUT WEST AS 700-500 MBS WILL RAMP UP TO 25 TO 35 KTS. A
SOMEWHAT DRIER AIRMASS WILL MOVE IN FOR WEDNESDAY WHILE TEMPS
CONTINUE TO WARM UNDER AMPLIFIED SOUTHWEST FLOW. PRECIP CHANCES
WILL BE LESS OVERALL BUT CANT RULE OUT A TSTM OR TWO OVER THE
MOUNTAINS.

.LONG TERM...(THURSDAY THROUGH SUNDAY)
ISSUED AT 431 AM MDT MON AUG 31 2015

THURSDAY...DRY AND MILD DAY UNDER SOUTHWEST FLOW ALOFT AND WITH
LIMITED LOW AND MID LEVEL MOISTURE TO FUEL THUNDERSTORMS.

FRIDAY...FLOW ALOFT REMAINS SOUTHWEST. HOWEVER...WITH AN INCREASE IN
LOW AND MID LEVEL MOISTURE AND LOW LEVEL UPSLOPE WINDS...EXPECT
ISOLATED LATE DAY SHOWERS AND THUNDERSTORMS MAINLY ALONG AND EAST OF
THE LARAMIE RANGE.

SATURDAY...NEXT MORE POTENT SHORTWAVE TROUGH ALOFT MOVES ACROSS
MONTANA. EXPECT ISOLATED LATE DAY THUNDERSTORMS TO DEVELOP IN OUR
COUNTIES ALONG A CONVERGENCE BOUNDARY.

SUNDAY...MOSTLY DRY DAY IN THE WAKE OF A COLD FRONT AS DRIER AND
MORE STABLE AIRMASS MOVES IN.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 431 AM MDT MON AUG 31 2015

VFR PREVAILS. ISOLATED TO SCATTERED AFTERNOON AND EVENING
THUNDERSTORMS FROM CHEYENNE WEST WITH LOCALIZED MVFR AND GUSTY AND
ERRATIC WIND.|

&&

.FIRE WEATHER...
ISSUED AT 431 AM MDT MON AUG 31 2015

WIDELY SCATTERED LIGHT RAIN SHOWERS WILL CONTINUE TO MOVE NORTHEAST
ACROSS THE DISTRICT THIS MORNING. BREEZY SOUTHWEST WINDS OF 25 TO 35
MPH WITH A FEW HIGHER GUSTS WILL ALSO PERSIST AHEAD OF A COLD FRONT
THAT WILL DROP SOUTH ACROSS THE EASTERN PLAINS AFTER SUNRISE.
WINDS ACROSS THE PLAINS BEHIND THE FRONT WILL SWITCH TO THE NORTH
WITH GUSTS TO 25 MPH...THEN WILL VEER TO THE SOUTHEAST THROUGH THE
AFTERNOON. A FEW SHOWERS AND TSTORMS WILL RETURN TO THE MOUNTAINS AND
NEARBY EASTERN PLAINS THIS AFTERNOON AS ENERGETIC SUBTROPICAL FLOW
REMAINS OVERHEAD. COOLER TEMPS TODAY WILL BE SHORT-LIVED WITH VERY
WARM...DRY AND BREEZY CONDITIONS LOOKING TO RETURN TO SOUTHEAST
WYOMING THROUGH THE END OF THE WEEK.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&

$$

SHORT TERM...RJM
LONG TERM...RUBIN
AVIATION...RUBIN
FIRE WEATHER...RJM



000
FXUS65 KCYS 311032
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
432 AM MDT MON AUG 31 2015

.SHORT TERM...(TODAY THROUGH WEDNESDAY NIGHT)
ISSUED AT 431 AM MDT MON AUG 31 2015

SCATTERED SHOWERS WILL CONTINUE EARLY THIS MORNING AHEAD OF A
SHORTWAVE MOVING UP FROM THE SOUTHWEST WITHIN THE RIGHT ENTRANCE
REGION OF AN UPPER LEVEL JET MAX. A FEW LIGHTNING STRIKES HAVE BEEN
OBSERVED OVER NORTHWEST COLORADO THE PAST FEW HOURS...SO CANT
RULE OUT AN ISOLATED STORM OVER THE SOUTHERN WYOMING MOUNTAINS AS
WELL. THE COLD FRONT LOOKS TO BE DRAPED ACROSS NORTHERN WYOMING
ACCORDING TO 4AM SFC OBS AND SHOULD BEGIN TO MOVE ACROSS OUR
EASTERN COUNTIES AROUND SUNRISE. AHEAD OF THE FRONT...SOUTHWEST
WINDS HAVE BECOME QUITE BREEZY OVERNIGHT WITH GUSTS ON AVERAGE OF
25 TO 35 MPH...WITH A FEW SPOTS ALONG AND WEST OF THE LARAMIE
RANGE REPORTING HIGHER SPEEDS. WILL SEE THESE WINDS PERSIST
THROUGH THE MORNING AS THE FRONT SLIDES SOUTH ACROSS THE
PLAINS...AND WINDS BEHIND THE FRONT WILL VEER TO THE NORTH
REMAINING GUSTY AT TIMES.

TEMPS WILL BE COOLER TODAY IN THE POST FRONTAL AIRMASS WITH
READINGS EXPECTED TO REMAIN IN THE 70S AND 80S. AS THE SFC HIGH
DROPS INTO THE CENTRAL PLAINS...SFC WINDS WILL VEER FURTHER TO A
SOUTHEASTERLY UPSLOPE COMPONENT THROUGH THE AFTERNOON. UPPER LEVEL
FLOW WILL REMAIN OUT OF THE SOUTHWEST WITH A CONTINUED STREAM OF
SUBTROPICAL MOISTURE...SO MAINTAINED A CHANCE FOR SHOWERS AND
TSTMS THIS AFTERNOON OVER THE MOUNTAINS BUT ALSO EXPANDED SLIGHT
CHANCES EASTWARD WITHIN THE UPSLOPE REGIME...ALTHO COVERAGE IN
THIS AREA WILL REMAIN VERY ISOLATED. ALTHO LLVL MOISTURE WILL BE
HIGHER THAN YESTERDAY...GUSTY WINDS ARE STILL A GOOD BET WITH THIS
ACTIVITY.

TUESDAY WILL BE WARMER AS THE COLDER AIRMASS RETREATS TO THE EAST
AND ANOTHER SHORTWAVE EMBEDDED IN SOUTHWEST FLOW LOOKS TO MOVE
OVERHEAD BRINGING ADDITIONAL CHANCES FOR AFTERNOON SHOWERS AND
TSTMS BUT MAINLY TO THE MOUNTAINS. A STRONG UPPER LOW WILL DIG
INTO THE PAC NW ON WEDNESDAY AND SHOULD DEEPEN THE LEESIDE
PRESSURE TROUGH THRU WEDNESDAY MORNING/AFTERNOON. SFC WINDS WILL
INCREASE IN RESPONSE WITH GUSTS OF 30 TO 35 MPH POSSIBLE THRU THE
AFTERNOON OUT WEST AS 700-500 MBS WILL RAMP UP TO 25 TO 35 KTS. A
SOMEWHAT DRIER AIRMASS WILL MOVE IN FOR WEDNESDAY WHILE TEMPS
CONTINUE TO WARM UNDER AMPLIFIED SOUTHWEST FLOW. PRECIP CHANCES
WILL BE LESS OVERALL BUT CANT RULE OUT A TSTM OR TWO OVER THE
MOUNTAINS.

.LONG TERM...(THURSDAY THROUGH SUNDAY)
ISSUED AT 431 AM MDT MON AUG 31 2015

THURSDAY...DRY AND MILD DAY UNDER SOUTHWEST FLOW ALOFT AND WITH
LIMITED LOW AND MID LEVEL MOISTURE TO FUEL THUNDERSTORMS.

FRIDAY...FLOW ALOFT REMAINS SOUTHWEST. HOWEVER...WITH AN INCREASE IN
LOW AND MID LEVEL MOISTURE AND LOW LEVEL UPSLOPE WINDS...EXPECT
ISOLATED LATE DAY SHOWERS AND THUNDERSTORMS MAINLY ALONG AND EAST OF
THE LARAMIE RANGE.

SATURDAY...NEXT MORE POTENT SHORTWAVE TROUGH ALOFT MOVES ACROSS
MONTANA. EXPECT ISOLATED LATE DAY THUNDERSTORMS TO DEVELOP IN OUR
COUNTIES ALONG A CONVERGENCE BOUNDARY.

SUNDAY...MOSTLY DRY DAY IN THE WAKE OF A COLD FRONT AS DRIER AND
MORE STABLE AIRMASS MOVES IN.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 431 AM MDT MON AUG 31 2015

VFR PREVAILS. ISOLATED TO SCATTERED AFTERNOON AND EVENING
THUNDERSTORMS FROM CHEYENNE WEST WITH LOCALIZED MVFR AND GUSTY AND
ERRATIC WIND.|

&&

.FIRE WEATHER...
ISSUED AT 431 AM MDT MON AUG 31 2015

WIDELY SCATTERED LIGHT RAIN SHOWERS WILL CONTINUE TO MOVE NORTHEAST
ACROSS THE DISTRICT THIS MORNING. BREEZY SOUTHWEST WINDS OF 25 TO 35
MPH WITH A FEW HIGHER GUSTS WILL ALSO PERSIST AHEAD OF A COLD FRONT
THAT WILL DROP SOUTH ACROSS THE EASTERN PLAINS AFTER SUNRISE.
WINDS ACROSS THE PLAINS BEHIND THE FRONT WILL SWITCH TO THE NORTH
WITH GUSTS TO 25 MPH...THEN WILL VEER TO THE SOUTHEAST THROUGH THE
AFTERNOON. A FEW SHOWERS AND TSTORMS WILL RETURN TO THE MOUNTAINS AND
NEARBY EASTERN PLAINS THIS AFTERNOON AS ENERGETIC SUBTROPICAL FLOW
REMAINS OVERHEAD. COOLER TEMPS TODAY WILL BE SHORT-LIVED WITH VERY
WARM...DRY AND BREEZY CONDITIONS LOOKING TO RETURN TO SOUTHEAST
WYOMING THROUGH THE END OF THE WEEK.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&

$$

SHORT TERM...RJM
LONG TERM...RUBIN
AVIATION...RUBIN
FIRE WEATHER...RJM



000
FXUS63 KUNR 310928
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
328 AM MDT MON AUG 31 2015

.SHORT TERM...TODAY THROUGH TUESDAY NIGHT
ISSUED AT 327 AM MDT MON AUG 31 2015

WATER VAPOR IMAGERY SHOWS STRONG UPPER WAVE CROSSING CNTRL TO ERN MT
INTO NRN WY. SURFACE ANALYSIS SHOWS LOW PRES ACROSS THE WRN/CNTRL
DAKOTAS AHEAD OF THE UPPER WAVE...WITH A COLD FRONT QUICKLY PUSHING
THRU ERN MT/CNTRL WY TOWARD THE CWA. TEMPS ACROSS THE CWA ARE IN THE
60S/70S...EVEN 80S ACROSS THE DOWNSLOPING N/NE BLKHLS. BEHIND THE
FRONT...OBS SHOWING TEMPS DROPPING INTO THE 50S WITH WINDS OF 15 TO
30 GUSTING TO 30 TO 40 MPH. RADAR SHOWS SHOWER ACTIVITY CROSSING WRN
SD...HOWEVER NEARLY ALL THE PRECIP IS VIRGA WITH LITTLE TO NO RAIN
REACHING THE GROUND. THE COLD FRONT WILL PUSH THROUGH NE WY TO WRN
SD IN THE NEXT 4/5 HOURS OR SO...AND CLEAR SCNTRL SD BY MID TO LATE
MORNING. HRRR SUGGESTS WINDS WILL GENERALLY BE 15 TO 25 MPH WITH
GUSTS TO 30 TO 40 MPH...BUT IS ALSO SHOWING STRONGER WINDS ACROSS
THE WRN SD PLAINS NORTH AND EAST OF THE BLKHLS. WIND ADVISORY
CRITERIA WINDS ARE EXPECTED...HOWEVER JUST FOR COUPLE HOURS OR SO
IMMEDIATELY AFTER THE FROPA. COULD SEE LINGERING SHRA ACTIVITY EARLY
THIS MORNING AS MODELS ARE HAVING A HARD TIME DECIDING HOW MUCH
PRECIP WILL REACH THE GROUND. WILL LEAN TOWARD A DRY FORECAST FOR
NOW CONSIDERING THE LATEST RADAR IMAGERY...BUT WILL REASSESS CLOSER
TO 12Z. OTHERWISE A DRY DAY IS EXPECTED WITH MUCH COOLER
TEMPERATURES AND CLEARING SKIES. HIGHS WILL REACH THE UPPER 70S TO
UPPER 80S. TEMPS TONIGHT WILL DROP INTO THE 50S TO LOWER 60S. RETURN
FLOW WILL SET UP BY MON NGHT/TUE MRNG WITH WARMER TEMPS EXPECTED.
HIGHS WILL RETURN TO THE MID 80S TO MID 90S. DRY WEATHER WILL
CONTINUE TUE/TUE NGHT WITH BROAD SWRLY FLOW ALOFT PERSISTING.

.LONG TERM...WEDNESDAY THROUGH SUNDAY
ISSUED AT 327 AM MDT MON AUG 31 2015

THE UPPER TROUGH WILL REMAIN OVER THE NORTH AMERICAN PACIFIC
COAST THROUGH MOST OF THE WEEK...EVENTUALLY MOVING INLAND BY THE
WEEKEND AS ANOTHER IMPULSE DROPS INTO THE UPPER TROUGH FROM THE
NORTHWEST. THIS PATTERN WILL LEAD TO CONTINUED VERY WARM
TEMPERATURES OVER THE NORTHERN PLAINS BOTH WEDNESDAY AND THURSDAY.
FRIDAY AND SATURDAY WILL BE SLIGHTLY COOLER...WITH MUCH COOLER
TEMPS ON SUNDAY AND MONDAY BEHIND A RELATIVELY STRONG COLD FRONT
WHICH WILL PASS THROUGH THE AREA EARLY SUNDAY. DRY WEATHER IS
EXPECTED ON WEDNESDAY AND THURSDAY WITH A CHANCE OF THUNDERSTORMS
EACH DAY FROM FRIDAY THROUGH THE WEEKEND AS A SERIES OF UPPER
IMPULSES CROSS THE REGION AND COOLER AIR FLOWS IN AT THE SFC.

&&

.AVIATION...FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING
ISSUED AT 327 AM MDT MON AUG 31 2015

BREEZY NORTHWEST WINDS WILL FOLLOW A COLD FRONT THIS MORNING. VFR
CONDITIONS ARE EXPECTED TODAY AND TONIGHT.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
WY...NONE.
&&

$$

SHORT TERM...13
LONG TERM...10
AVIATION...10



000
FXUS63 KUNR 310928
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
328 AM MDT MON AUG 31 2015

.SHORT TERM...TODAY THROUGH TUESDAY NIGHT
ISSUED AT 327 AM MDT MON AUG 31 2015

WATER VAPOR IMAGERY SHOWS STRONG UPPER WAVE CROSSING CNTRL TO ERN MT
INTO NRN WY. SURFACE ANALYSIS SHOWS LOW PRES ACROSS THE WRN/CNTRL
DAKOTAS AHEAD OF THE UPPER WAVE...WITH A COLD FRONT QUICKLY PUSHING
THRU ERN MT/CNTRL WY TOWARD THE CWA. TEMPS ACROSS THE CWA ARE IN THE
60S/70S...EVEN 80S ACROSS THE DOWNSLOPING N/NE BLKHLS. BEHIND THE
FRONT...OBS SHOWING TEMPS DROPPING INTO THE 50S WITH WINDS OF 15 TO
30 GUSTING TO 30 TO 40 MPH. RADAR SHOWS SHOWER ACTIVITY CROSSING WRN
SD...HOWEVER NEARLY ALL THE PRECIP IS VIRGA WITH LITTLE TO NO RAIN
REACHING THE GROUND. THE COLD FRONT WILL PUSH THROUGH NE WY TO WRN
SD IN THE NEXT 4/5 HOURS OR SO...AND CLEAR SCNTRL SD BY MID TO LATE
MORNING. HRRR SUGGESTS WINDS WILL GENERALLY BE 15 TO 25 MPH WITH
GUSTS TO 30 TO 40 MPH...BUT IS ALSO SHOWING STRONGER WINDS ACROSS
THE WRN SD PLAINS NORTH AND EAST OF THE BLKHLS. WIND ADVISORY
CRITERIA WINDS ARE EXPECTED...HOWEVER JUST FOR COUPLE HOURS OR SO
IMMEDIATELY AFTER THE FROPA. COULD SEE LINGERING SHRA ACTIVITY EARLY
THIS MORNING AS MODELS ARE HAVING A HARD TIME DECIDING HOW MUCH
PRECIP WILL REACH THE GROUND. WILL LEAN TOWARD A DRY FORECAST FOR
NOW CONSIDERING THE LATEST RADAR IMAGERY...BUT WILL REASSESS CLOSER
TO 12Z. OTHERWISE A DRY DAY IS EXPECTED WITH MUCH COOLER
TEMPERATURES AND CLEARING SKIES. HIGHS WILL REACH THE UPPER 70S TO
UPPER 80S. TEMPS TONIGHT WILL DROP INTO THE 50S TO LOWER 60S. RETURN
FLOW WILL SET UP BY MON NGHT/TUE MRNG WITH WARMER TEMPS EXPECTED.
HIGHS WILL RETURN TO THE MID 80S TO MID 90S. DRY WEATHER WILL
CONTINUE TUE/TUE NGHT WITH BROAD SWRLY FLOW ALOFT PERSISTING.

.LONG TERM...WEDNESDAY THROUGH SUNDAY
ISSUED AT 327 AM MDT MON AUG 31 2015

THE UPPER TROUGH WILL REMAIN OVER THE NORTH AMERICAN PACIFIC
COAST THROUGH MOST OF THE WEEK...EVENTUALLY MOVING INLAND BY THE
WEEKEND AS ANOTHER IMPULSE DROPS INTO THE UPPER TROUGH FROM THE
NORTHWEST. THIS PATTERN WILL LEAD TO CONTINUED VERY WARM
TEMPERATURES OVER THE NORTHERN PLAINS BOTH WEDNESDAY AND THURSDAY.
FRIDAY AND SATURDAY WILL BE SLIGHTLY COOLER...WITH MUCH COOLER
TEMPS ON SUNDAY AND MONDAY BEHIND A RELATIVELY STRONG COLD FRONT
WHICH WILL PASS THROUGH THE AREA EARLY SUNDAY. DRY WEATHER IS
EXPECTED ON WEDNESDAY AND THURSDAY WITH A CHANCE OF THUNDERSTORMS
EACH DAY FROM FRIDAY THROUGH THE WEEKEND AS A SERIES OF UPPER
IMPULSES CROSS THE REGION AND COOLER AIR FLOWS IN AT THE SFC.

&&

.AVIATION...FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING
ISSUED AT 327 AM MDT MON AUG 31 2015

BREEZY NORTHWEST WINDS WILL FOLLOW A COLD FRONT THIS MORNING. VFR
CONDITIONS ARE EXPECTED TODAY AND TONIGHT.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
WY...NONE.
&&

$$

SHORT TERM...13
LONG TERM...10
AVIATION...10



000
FXUS63 KUNR 310928
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
328 AM MDT MON AUG 31 2015

.SHORT TERM...TODAY THROUGH TUESDAY NIGHT
ISSUED AT 327 AM MDT MON AUG 31 2015

WATER VAPOR IMAGERY SHOWS STRONG UPPER WAVE CROSSING CNTRL TO ERN MT
INTO NRN WY. SURFACE ANALYSIS SHOWS LOW PRES ACROSS THE WRN/CNTRL
DAKOTAS AHEAD OF THE UPPER WAVE...WITH A COLD FRONT QUICKLY PUSHING
THRU ERN MT/CNTRL WY TOWARD THE CWA. TEMPS ACROSS THE CWA ARE IN THE
60S/70S...EVEN 80S ACROSS THE DOWNSLOPING N/NE BLKHLS. BEHIND THE
FRONT...OBS SHOWING TEMPS DROPPING INTO THE 50S WITH WINDS OF 15 TO
30 GUSTING TO 30 TO 40 MPH. RADAR SHOWS SHOWER ACTIVITY CROSSING WRN
SD...HOWEVER NEARLY ALL THE PRECIP IS VIRGA WITH LITTLE TO NO RAIN
REACHING THE GROUND. THE COLD FRONT WILL PUSH THROUGH NE WY TO WRN
SD IN THE NEXT 4/5 HOURS OR SO...AND CLEAR SCNTRL SD BY MID TO LATE
MORNING. HRRR SUGGESTS WINDS WILL GENERALLY BE 15 TO 25 MPH WITH
GUSTS TO 30 TO 40 MPH...BUT IS ALSO SHOWING STRONGER WINDS ACROSS
THE WRN SD PLAINS NORTH AND EAST OF THE BLKHLS. WIND ADVISORY
CRITERIA WINDS ARE EXPECTED...HOWEVER JUST FOR COUPLE HOURS OR SO
IMMEDIATELY AFTER THE FROPA. COULD SEE LINGERING SHRA ACTIVITY EARLY
THIS MORNING AS MODELS ARE HAVING A HARD TIME DECIDING HOW MUCH
PRECIP WILL REACH THE GROUND. WILL LEAN TOWARD A DRY FORECAST FOR
NOW CONSIDERING THE LATEST RADAR IMAGERY...BUT WILL REASSESS CLOSER
TO 12Z. OTHERWISE A DRY DAY IS EXPECTED WITH MUCH COOLER
TEMPERATURES AND CLEARING SKIES. HIGHS WILL REACH THE UPPER 70S TO
UPPER 80S. TEMPS TONIGHT WILL DROP INTO THE 50S TO LOWER 60S. RETURN
FLOW WILL SET UP BY MON NGHT/TUE MRNG WITH WARMER TEMPS EXPECTED.
HIGHS WILL RETURN TO THE MID 80S TO MID 90S. DRY WEATHER WILL
CONTINUE TUE/TUE NGHT WITH BROAD SWRLY FLOW ALOFT PERSISTING.

.LONG TERM...WEDNESDAY THROUGH SUNDAY
ISSUED AT 327 AM MDT MON AUG 31 2015

THE UPPER TROUGH WILL REMAIN OVER THE NORTH AMERICAN PACIFIC
COAST THROUGH MOST OF THE WEEK...EVENTUALLY MOVING INLAND BY THE
WEEKEND AS ANOTHER IMPULSE DROPS INTO THE UPPER TROUGH FROM THE
NORTHWEST. THIS PATTERN WILL LEAD TO CONTINUED VERY WARM
TEMPERATURES OVER THE NORTHERN PLAINS BOTH WEDNESDAY AND THURSDAY.
FRIDAY AND SATURDAY WILL BE SLIGHTLY COOLER...WITH MUCH COOLER
TEMPS ON SUNDAY AND MONDAY BEHIND A RELATIVELY STRONG COLD FRONT
WHICH WILL PASS THROUGH THE AREA EARLY SUNDAY. DRY WEATHER IS
EXPECTED ON WEDNESDAY AND THURSDAY WITH A CHANCE OF THUNDERSTORMS
EACH DAY FROM FRIDAY THROUGH THE WEEKEND AS A SERIES OF UPPER
IMPULSES CROSS THE REGION AND COOLER AIR FLOWS IN AT THE SFC.

&&

.AVIATION...FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING
ISSUED AT 327 AM MDT MON AUG 31 2015

BREEZY NORTHWEST WINDS WILL FOLLOW A COLD FRONT THIS MORNING. VFR
CONDITIONS ARE EXPECTED TODAY AND TONIGHT.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
WY...NONE.
&&

$$

SHORT TERM...13
LONG TERM...10
AVIATION...10



000
FXUS63 KUNR 310928
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
328 AM MDT MON AUG 31 2015

.SHORT TERM...TODAY THROUGH TUESDAY NIGHT
ISSUED AT 327 AM MDT MON AUG 31 2015

WATER VAPOR IMAGERY SHOWS STRONG UPPER WAVE CROSSING CNTRL TO ERN MT
INTO NRN WY. SURFACE ANALYSIS SHOWS LOW PRES ACROSS THE WRN/CNTRL
DAKOTAS AHEAD OF THE UPPER WAVE...WITH A COLD FRONT QUICKLY PUSHING
THRU ERN MT/CNTRL WY TOWARD THE CWA. TEMPS ACROSS THE CWA ARE IN THE
60S/70S...EVEN 80S ACROSS THE DOWNSLOPING N/NE BLKHLS. BEHIND THE
FRONT...OBS SHOWING TEMPS DROPPING INTO THE 50S WITH WINDS OF 15 TO
30 GUSTING TO 30 TO 40 MPH. RADAR SHOWS SHOWER ACTIVITY CROSSING WRN
SD...HOWEVER NEARLY ALL THE PRECIP IS VIRGA WITH LITTLE TO NO RAIN
REACHING THE GROUND. THE COLD FRONT WILL PUSH THROUGH NE WY TO WRN
SD IN THE NEXT 4/5 HOURS OR SO...AND CLEAR SCNTRL SD BY MID TO LATE
MORNING. HRRR SUGGESTS WINDS WILL GENERALLY BE 15 TO 25 MPH WITH
GUSTS TO 30 TO 40 MPH...BUT IS ALSO SHOWING STRONGER WINDS ACROSS
THE WRN SD PLAINS NORTH AND EAST OF THE BLKHLS. WIND ADVISORY
CRITERIA WINDS ARE EXPECTED...HOWEVER JUST FOR COUPLE HOURS OR SO
IMMEDIATELY AFTER THE FROPA. COULD SEE LINGERING SHRA ACTIVITY EARLY
THIS MORNING AS MODELS ARE HAVING A HARD TIME DECIDING HOW MUCH
PRECIP WILL REACH THE GROUND. WILL LEAN TOWARD A DRY FORECAST FOR
NOW CONSIDERING THE LATEST RADAR IMAGERY...BUT WILL REASSESS CLOSER
TO 12Z. OTHERWISE A DRY DAY IS EXPECTED WITH MUCH COOLER
TEMPERATURES AND CLEARING SKIES. HIGHS WILL REACH THE UPPER 70S TO
UPPER 80S. TEMPS TONIGHT WILL DROP INTO THE 50S TO LOWER 60S. RETURN
FLOW WILL SET UP BY MON NGHT/TUE MRNG WITH WARMER TEMPS EXPECTED.
HIGHS WILL RETURN TO THE MID 80S TO MID 90S. DRY WEATHER WILL
CONTINUE TUE/TUE NGHT WITH BROAD SWRLY FLOW ALOFT PERSISTING.

.LONG TERM...WEDNESDAY THROUGH SUNDAY
ISSUED AT 327 AM MDT MON AUG 31 2015

THE UPPER TROUGH WILL REMAIN OVER THE NORTH AMERICAN PACIFIC
COAST THROUGH MOST OF THE WEEK...EVENTUALLY MOVING INLAND BY THE
WEEKEND AS ANOTHER IMPULSE DROPS INTO THE UPPER TROUGH FROM THE
NORTHWEST. THIS PATTERN WILL LEAD TO CONTINUED VERY WARM
TEMPERATURES OVER THE NORTHERN PLAINS BOTH WEDNESDAY AND THURSDAY.
FRIDAY AND SATURDAY WILL BE SLIGHTLY COOLER...WITH MUCH COOLER
TEMPS ON SUNDAY AND MONDAY BEHIND A RELATIVELY STRONG COLD FRONT
WHICH WILL PASS THROUGH THE AREA EARLY SUNDAY. DRY WEATHER IS
EXPECTED ON WEDNESDAY AND THURSDAY WITH A CHANCE OF THUNDERSTORMS
EACH DAY FROM FRIDAY THROUGH THE WEEKEND AS A SERIES OF UPPER
IMPULSES CROSS THE REGION AND COOLER AIR FLOWS IN AT THE SFC.

&&

.AVIATION...FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING
ISSUED AT 327 AM MDT MON AUG 31 2015

BREEZY NORTHWEST WINDS WILL FOLLOW A COLD FRONT THIS MORNING. VFR
CONDITIONS ARE EXPECTED TODAY AND TONIGHT.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
WY...NONE.
&&

$$

SHORT TERM...13
LONG TERM...10
AVIATION...10


  [top]

000
FXUS65 KRIW 310819 CCA
AFDRIW

AREA FORECAST DISCUSSION...CORRECTED
NATIONAL WEATHER SERVICE RIVERTON WY
219 AM MDT MON AUG 31 2015

.SHORT TERM...TODAY THROUGH WEDNESDAY NIGHT

THE THUNDERSTORMS THAT OCCURRED EARLIER THIS EVENING WERE FAST MOVING
WITH HEAVY RAINFALL BUT WITH A SHORT RESIDENCE TIME AND FREQUENT
LIGHTNING ALONG WITH UP TO 40 MPH WIND GUSTS. THE FROPA AND
HAS OCCURRED AND THE SHOWERS HAVE EXITED OFF TO THE EAST AND
DISSIPATED. CONFLUENT FLOW HAS TAKEN OVER. TODAY SOME INSTABILITY
WILL LINGER IN THE FAR SOUTH AND UP INTO SOUTHWEST NATRONA COUNTY
WHERE ISOLATED T STORMS ARE EXPECTED WITH SOME CONVECTION
STREAMING OFF THE UINTAS INTO SOUTHERN SWEETWATER COUNTY. ON
TUESDAY EXPECT ISOLD T STORMS ONLY IN THE NW MTNS WHEN CAPES
INCREASE SLIGHTLY BUT ARE NOT EXPECTED TO MOVE OFF THE MTNS.
WEDNESDAY WILL FEATURE INCREASE SOUTHWEST WINDS AS A CLOSED LOW
MOVES INLAND INTO BC AND THE ASCT TROUGH MAKES LANDFALL ONTO THE
PAC NW COAST THUS INCREASING OUR SOUTHWEST GRADIENT. TEMPS WILL BE
SLIGHTLY COOLER TODAY AND THEN BEGIN A WARMING TREND TUESDAY WITH
WEDNESDAY BEING THE WARMEST DAY OF THE PERIOD.

.LONG TERM...THURSDAY THROUGH MONDAY

MAJOR MEDIUM RANGE DIFFERENCES TONIGHT AS TO THE EVOLUTION OF OUR
LATE WEEK TROUGH. THE MODELS DO AGREE THAT THERE WILL BE A COLD
TROUGH OVER THE PACNW/NRN ROCKIES TO START THE PERIOD BUT HOW THIS
TROUGH TRANSLATES EWD WITH TIME IS WHERE THEY DEPART SIGNIFICANTLY.
THE GFS IS THE FASTEST TO MOVE THIS TROUGH OUT OF THE WAY BY
SATURDAY NIGHT WHILE THE ECMWF/GEM DON`T SWING THE TROUGH THROUGH
UNTIL MONDAY MORNING. THE FIRST SHORTWAVE THAT GETS KICKED OUT BY
THE DEVELOPING COLD TROUGH SHOULD LIFT NE ACROSS THE NRN ROCKIES
THURSDAY INTO THURSDAY NIGHT LEADING TO THE FRONT SAGGING SWD INTO
OUR NRN ZONES BEHIND THIS WAVE. THE GFS THEN KEEPS THIS FRONT IN THE
FAR NORTH PRETTY MUCH THROUGH THE PERIOD WITH SHARPLY COOLER TEMPS
BEHIND IT. THE ECMWF WASHES IT OUT EXCEPT MAYBE NEAR THE NRN BORDER
AS IT DEVELOPS AN INTENSE UPPER LOW OVER IDAHO ON SATURDAY THAT
LIFTS ACROSS THE PARK SATURDAY NIGHT WITH -4C AIR AT H7. LEANING
TOWARDS A STRONGER...SLOWER TROUGH...MAYBE NOT ECMWF STRONG...BUT
MORE TOWARDS THAT TIMING. WILL HAVE TO LOOK AT THIS AGAIN TONIGHT
AND HIT THE POPS MUCH HARDER IF THESE TRENDS CONTINUE AND THE MODELS
COME INTO BETTER AGREEMENT. POTENTIAL FOR A COLD LABOR DAY WEEKEND
WITH COLD RAIN AND MOUNTAIN SNOW IS STILL QUITE POSSIBLE IN THE
NORTHWEST PART OF WYOMING INCLUDING YELLOWSTONE NATIONAL PARK.
OTHERWISE...STILL WARM AND BREEZY TO WINDY AHEAD OF THE FRONT
THURSDAY AND IN THE SOUTH THROUGH AT LEAST FRIDAY BEFORE COOLER TO
COLDER AIR FILTERS IN. THE  WEST AND NORTH WILL SEE THE LONGEST
PERIOD OF COOLER WEATHER AND POTENTIALLY DOWNRIGHT COLD IN YNP OVER
THE WEEKEND.

&&

.AVIATION.../12Z ISSUANCE/

A COLD FRONT WILL PLUNGE SOUTH ACROSS NORTH AND CENTRAL WYOMING THROUGH 09Z.
GUSTY NORTH WIND AT 15 TO 25 KT WILL FOLLOW THE FRONT VCNTY AND
NORTH OF A KGEY TO KBYG LINE WITH WINDS NOT QUITE AS STRONG
FURTHER SOUTH. A FEW THUNDERSTORMS WILL ALSO CONTINUE VCNTY AND
SOUTH OF INTERSTATE 80 THROUGH 9Z. WINDS WILL DIMINISH BY 12Z.

ON MONDAY...ISOLATED TO WIDELY SCATTERED THUNDERSTORMS WILL DEVELOP MONDAY
AFTERNOON VCNTY OF A KRKS-KCPR LINE. SURFACE HIGH PRESSURE WILL
KEEP NORTHERN WYOMING UNDER PREVAILING SKC-FEW FL150-200
CONDITIONS AND S-SE WINDS AROUND 10KTS. THUNDERSTORM ACTIVITY WILL
MOSTLY END ACROSS THE SOUTH BY 3Z TUESDAY.

&&

.FIRE WEATHER...

IT WILL BE DRY TODAY BEHIND THIS MORNINGS COOL FRONT BUT A BIT
COOLER. THERE WILL BE SOME 20 MPH BREEZES IN THE AFTERNOON BUT RED
FLAG CONDITIONS ARE NOT EXPECTED. FOR THE REST OF THE WEEK THE
MINIMUM RELATIVE HUMIDITY WILL BE MAINLY IN THE TEENS AT THE LOWER
ELEVATIONS EAST OF THE DIVIDE AND 20S WEST. SOUTHWEST WINDS WILL
INCREASE WEDNESDAY OUT AHEAD OF THE NEXT DEVELOPING PACIFIC
TROUGH.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...NONE.

&&

$$

SHORT TERM...LIPSON
LONG TERM...PS
AVIATION...AEM
FIRE WEATHER...LIPSON




000
FXUS65 KRIW 310819 CCA
AFDRIW

AREA FORECAST DISCUSSION...CORRECTED
NATIONAL WEATHER SERVICE RIVERTON WY
219 AM MDT MON AUG 31 2015

.SHORT TERM...TODAY THROUGH WEDNESDAY NIGHT

THE THUNDERSTORMS THAT OCCURRED EARLIER THIS EVENING WERE FAST MOVING
WITH HEAVY RAINFALL BUT WITH A SHORT RESIDENCE TIME AND FREQUENT
LIGHTNING ALONG WITH UP TO 40 MPH WIND GUSTS. THE FROPA AND
HAS OCCURRED AND THE SHOWERS HAVE EXITED OFF TO THE EAST AND
DISSIPATED. CONFLUENT FLOW HAS TAKEN OVER. TODAY SOME INSTABILITY
WILL LINGER IN THE FAR SOUTH AND UP INTO SOUTHWEST NATRONA COUNTY
WHERE ISOLATED T STORMS ARE EXPECTED WITH SOME CONVECTION
STREAMING OFF THE UINTAS INTO SOUTHERN SWEETWATER COUNTY. ON
TUESDAY EXPECT ISOLD T STORMS ONLY IN THE NW MTNS WHEN CAPES
INCREASE SLIGHTLY BUT ARE NOT EXPECTED TO MOVE OFF THE MTNS.
WEDNESDAY WILL FEATURE INCREASE SOUTHWEST WINDS AS A CLOSED LOW
MOVES INLAND INTO BC AND THE ASCT TROUGH MAKES LANDFALL ONTO THE
PAC NW COAST THUS INCREASING OUR SOUTHWEST GRADIENT. TEMPS WILL BE
SLIGHTLY COOLER TODAY AND THEN BEGIN A WARMING TREND TUESDAY WITH
WEDNESDAY BEING THE WARMEST DAY OF THE PERIOD.

.LONG TERM...THURSDAY THROUGH MONDAY

MAJOR MEDIUM RANGE DIFFERENCES TONIGHT AS TO THE EVOLUTION OF OUR
LATE WEEK TROUGH. THE MODELS DO AGREE THAT THERE WILL BE A COLD
TROUGH OVER THE PACNW/NRN ROCKIES TO START THE PERIOD BUT HOW THIS
TROUGH TRANSLATES EWD WITH TIME IS WHERE THEY DEPART SIGNIFICANTLY.
THE GFS IS THE FASTEST TO MOVE THIS TROUGH OUT OF THE WAY BY
SATURDAY NIGHT WHILE THE ECMWF/GEM DON`T SWING THE TROUGH THROUGH
UNTIL MONDAY MORNING. THE FIRST SHORTWAVE THAT GETS KICKED OUT BY
THE DEVELOPING COLD TROUGH SHOULD LIFT NE ACROSS THE NRN ROCKIES
THURSDAY INTO THURSDAY NIGHT LEADING TO THE FRONT SAGGING SWD INTO
OUR NRN ZONES BEHIND THIS WAVE. THE GFS THEN KEEPS THIS FRONT IN THE
FAR NORTH PRETTY MUCH THROUGH THE PERIOD WITH SHARPLY COOLER TEMPS
BEHIND IT. THE ECMWF WASHES IT OUT EXCEPT MAYBE NEAR THE NRN BORDER
AS IT DEVELOPS AN INTENSE UPPER LOW OVER IDAHO ON SATURDAY THAT
LIFTS ACROSS THE PARK SATURDAY NIGHT WITH -4C AIR AT H7. LEANING
TOWARDS A STRONGER...SLOWER TROUGH...MAYBE NOT ECMWF STRONG...BUT
MORE TOWARDS THAT TIMING. WILL HAVE TO LOOK AT THIS AGAIN TONIGHT
AND HIT THE POPS MUCH HARDER IF THESE TRENDS CONTINUE AND THE MODELS
COME INTO BETTER AGREEMENT. POTENTIAL FOR A COLD LABOR DAY WEEKEND
WITH COLD RAIN AND MOUNTAIN SNOW IS STILL QUITE POSSIBLE IN THE
NORTHWEST PART OF WYOMING INCLUDING YELLOWSTONE NATIONAL PARK.
OTHERWISE...STILL WARM AND BREEZY TO WINDY AHEAD OF THE FRONT
THURSDAY AND IN THE SOUTH THROUGH AT LEAST FRIDAY BEFORE COOLER TO
COLDER AIR FILTERS IN. THE  WEST AND NORTH WILL SEE THE LONGEST
PERIOD OF COOLER WEATHER AND POTENTIALLY DOWNRIGHT COLD IN YNP OVER
THE WEEKEND.

&&

.AVIATION.../12Z ISSUANCE/

A COLD FRONT WILL PLUNGE SOUTH ACROSS NORTH AND CENTRAL WYOMING THROUGH 09Z.
GUSTY NORTH WIND AT 15 TO 25 KT WILL FOLLOW THE FRONT VCNTY AND
NORTH OF A KGEY TO KBYG LINE WITH WINDS NOT QUITE AS STRONG
FURTHER SOUTH. A FEW THUNDERSTORMS WILL ALSO CONTINUE VCNTY AND
SOUTH OF INTERSTATE 80 THROUGH 9Z. WINDS WILL DIMINISH BY 12Z.

ON MONDAY...ISOLATED TO WIDELY SCATTERED THUNDERSTORMS WILL DEVELOP MONDAY
AFTERNOON VCNTY OF A KRKS-KCPR LINE. SURFACE HIGH PRESSURE WILL
KEEP NORTHERN WYOMING UNDER PREVAILING SKC-FEW FL150-200
CONDITIONS AND S-SE WINDS AROUND 10KTS. THUNDERSTORM ACTIVITY WILL
MOSTLY END ACROSS THE SOUTH BY 3Z TUESDAY.

&&

.FIRE WEATHER...

IT WILL BE DRY TODAY BEHIND THIS MORNINGS COOL FRONT BUT A BIT
COOLER. THERE WILL BE SOME 20 MPH BREEZES IN THE AFTERNOON BUT RED
FLAG CONDITIONS ARE NOT EXPECTED. FOR THE REST OF THE WEEK THE
MINIMUM RELATIVE HUMIDITY WILL BE MAINLY IN THE TEENS AT THE LOWER
ELEVATIONS EAST OF THE DIVIDE AND 20S WEST. SOUTHWEST WINDS WILL
INCREASE WEDNESDAY OUT AHEAD OF THE NEXT DEVELOPING PACIFIC
TROUGH.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...NONE.

&&

$$

SHORT TERM...LIPSON
LONG TERM...PS
AVIATION...AEM
FIRE WEATHER...LIPSON




000
FXUS65 KRIW 310819 CCA
AFDRIW

AREA FORECAST DISCUSSION...CORRECTED
NATIONAL WEATHER SERVICE RIVERTON WY
219 AM MDT MON AUG 31 2015

.SHORT TERM...TODAY THROUGH WEDNESDAY NIGHT

THE THUNDERSTORMS THAT OCCURRED EARLIER THIS EVENING WERE FAST MOVING
WITH HEAVY RAINFALL BUT WITH A SHORT RESIDENCE TIME AND FREQUENT
LIGHTNING ALONG WITH UP TO 40 MPH WIND GUSTS. THE FROPA AND
HAS OCCURRED AND THE SHOWERS HAVE EXITED OFF TO THE EAST AND
DISSIPATED. CONFLUENT FLOW HAS TAKEN OVER. TODAY SOME INSTABILITY
WILL LINGER IN THE FAR SOUTH AND UP INTO SOUTHWEST NATRONA COUNTY
WHERE ISOLATED T STORMS ARE EXPECTED WITH SOME CONVECTION
STREAMING OFF THE UINTAS INTO SOUTHERN SWEETWATER COUNTY. ON
TUESDAY EXPECT ISOLD T STORMS ONLY IN THE NW MTNS WHEN CAPES
INCREASE SLIGHTLY BUT ARE NOT EXPECTED TO MOVE OFF THE MTNS.
WEDNESDAY WILL FEATURE INCREASE SOUTHWEST WINDS AS A CLOSED LOW
MOVES INLAND INTO BC AND THE ASCT TROUGH MAKES LANDFALL ONTO THE
PAC NW COAST THUS INCREASING OUR SOUTHWEST GRADIENT. TEMPS WILL BE
SLIGHTLY COOLER TODAY AND THEN BEGIN A WARMING TREND TUESDAY WITH
WEDNESDAY BEING THE WARMEST DAY OF THE PERIOD.

.LONG TERM...THURSDAY THROUGH MONDAY

MAJOR MEDIUM RANGE DIFFERENCES TONIGHT AS TO THE EVOLUTION OF OUR
LATE WEEK TROUGH. THE MODELS DO AGREE THAT THERE WILL BE A COLD
TROUGH OVER THE PACNW/NRN ROCKIES TO START THE PERIOD BUT HOW THIS
TROUGH TRANSLATES EWD WITH TIME IS WHERE THEY DEPART SIGNIFICANTLY.
THE GFS IS THE FASTEST TO MOVE THIS TROUGH OUT OF THE WAY BY
SATURDAY NIGHT WHILE THE ECMWF/GEM DON`T SWING THE TROUGH THROUGH
UNTIL MONDAY MORNING. THE FIRST SHORTWAVE THAT GETS KICKED OUT BY
THE DEVELOPING COLD TROUGH SHOULD LIFT NE ACROSS THE NRN ROCKIES
THURSDAY INTO THURSDAY NIGHT LEADING TO THE FRONT SAGGING SWD INTO
OUR NRN ZONES BEHIND THIS WAVE. THE GFS THEN KEEPS THIS FRONT IN THE
FAR NORTH PRETTY MUCH THROUGH THE PERIOD WITH SHARPLY COOLER TEMPS
BEHIND IT. THE ECMWF WASHES IT OUT EXCEPT MAYBE NEAR THE NRN BORDER
AS IT DEVELOPS AN INTENSE UPPER LOW OVER IDAHO ON SATURDAY THAT
LIFTS ACROSS THE PARK SATURDAY NIGHT WITH -4C AIR AT H7. LEANING
TOWARDS A STRONGER...SLOWER TROUGH...MAYBE NOT ECMWF STRONG...BUT
MORE TOWARDS THAT TIMING. WILL HAVE TO LOOK AT THIS AGAIN TONIGHT
AND HIT THE POPS MUCH HARDER IF THESE TRENDS CONTINUE AND THE MODELS
COME INTO BETTER AGREEMENT. POTENTIAL FOR A COLD LABOR DAY WEEKEND
WITH COLD RAIN AND MOUNTAIN SNOW IS STILL QUITE POSSIBLE IN THE
NORTHWEST PART OF WYOMING INCLUDING YELLOWSTONE NATIONAL PARK.
OTHERWISE...STILL WARM AND BREEZY TO WINDY AHEAD OF THE FRONT
THURSDAY AND IN THE SOUTH THROUGH AT LEAST FRIDAY BEFORE COOLER TO
COLDER AIR FILTERS IN. THE  WEST AND NORTH WILL SEE THE LONGEST
PERIOD OF COOLER WEATHER AND POTENTIALLY DOWNRIGHT COLD IN YNP OVER
THE WEEKEND.

&&

.AVIATION.../12Z ISSUANCE/

A COLD FRONT WILL PLUNGE SOUTH ACROSS NORTH AND CENTRAL WYOMING THROUGH 09Z.
GUSTY NORTH WIND AT 15 TO 25 KT WILL FOLLOW THE FRONT VCNTY AND
NORTH OF A KGEY TO KBYG LINE WITH WINDS NOT QUITE AS STRONG
FURTHER SOUTH. A FEW THUNDERSTORMS WILL ALSO CONTINUE VCNTY AND
SOUTH OF INTERSTATE 80 THROUGH 9Z. WINDS WILL DIMINISH BY 12Z.

ON MONDAY...ISOLATED TO WIDELY SCATTERED THUNDERSTORMS WILL DEVELOP MONDAY
AFTERNOON VCNTY OF A KRKS-KCPR LINE. SURFACE HIGH PRESSURE WILL
KEEP NORTHERN WYOMING UNDER PREVAILING SKC-FEW FL150-200
CONDITIONS AND S-SE WINDS AROUND 10KTS. THUNDERSTORM ACTIVITY WILL
MOSTLY END ACROSS THE SOUTH BY 3Z TUESDAY.

&&

.FIRE WEATHER...

IT WILL BE DRY TODAY BEHIND THIS MORNINGS COOL FRONT BUT A BIT
COOLER. THERE WILL BE SOME 20 MPH BREEZES IN THE AFTERNOON BUT RED
FLAG CONDITIONS ARE NOT EXPECTED. FOR THE REST OF THE WEEK THE
MINIMUM RELATIVE HUMIDITY WILL BE MAINLY IN THE TEENS AT THE LOWER
ELEVATIONS EAST OF THE DIVIDE AND 20S WEST. SOUTHWEST WINDS WILL
INCREASE WEDNESDAY OUT AHEAD OF THE NEXT DEVELOPING PACIFIC
TROUGH.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...NONE.

&&

$$

SHORT TERM...LIPSON
LONG TERM...PS
AVIATION...AEM
FIRE WEATHER...LIPSON




000
FXUS65 KRIW 310819 CCA
AFDRIW

AREA FORECAST DISCUSSION...CORRECTED
NATIONAL WEATHER SERVICE RIVERTON WY
219 AM MDT MON AUG 31 2015

.SHORT TERM...TODAY THROUGH WEDNESDAY NIGHT

THE THUNDERSTORMS THAT OCCURRED EARLIER THIS EVENING WERE FAST MOVING
WITH HEAVY RAINFALL BUT WITH A SHORT RESIDENCE TIME AND FREQUENT
LIGHTNING ALONG WITH UP TO 40 MPH WIND GUSTS. THE FROPA AND
HAS OCCURRED AND THE SHOWERS HAVE EXITED OFF TO THE EAST AND
DISSIPATED. CONFLUENT FLOW HAS TAKEN OVER. TODAY SOME INSTABILITY
WILL LINGER IN THE FAR SOUTH AND UP INTO SOUTHWEST NATRONA COUNTY
WHERE ISOLATED T STORMS ARE EXPECTED WITH SOME CONVECTION
STREAMING OFF THE UINTAS INTO SOUTHERN SWEETWATER COUNTY. ON
TUESDAY EXPECT ISOLD T STORMS ONLY IN THE NW MTNS WHEN CAPES
INCREASE SLIGHTLY BUT ARE NOT EXPECTED TO MOVE OFF THE MTNS.
WEDNESDAY WILL FEATURE INCREASE SOUTHWEST WINDS AS A CLOSED LOW
MOVES INLAND INTO BC AND THE ASCT TROUGH MAKES LANDFALL ONTO THE
PAC NW COAST THUS INCREASING OUR SOUTHWEST GRADIENT. TEMPS WILL BE
SLIGHTLY COOLER TODAY AND THEN BEGIN A WARMING TREND TUESDAY WITH
WEDNESDAY BEING THE WARMEST DAY OF THE PERIOD.

.LONG TERM...THURSDAY THROUGH MONDAY

MAJOR MEDIUM RANGE DIFFERENCES TONIGHT AS TO THE EVOLUTION OF OUR
LATE WEEK TROUGH. THE MODELS DO AGREE THAT THERE WILL BE A COLD
TROUGH OVER THE PACNW/NRN ROCKIES TO START THE PERIOD BUT HOW THIS
TROUGH TRANSLATES EWD WITH TIME IS WHERE THEY DEPART SIGNIFICANTLY.
THE GFS IS THE FASTEST TO MOVE THIS TROUGH OUT OF THE WAY BY
SATURDAY NIGHT WHILE THE ECMWF/GEM DON`T SWING THE TROUGH THROUGH
UNTIL MONDAY MORNING. THE FIRST SHORTWAVE THAT GETS KICKED OUT BY
THE DEVELOPING COLD TROUGH SHOULD LIFT NE ACROSS THE NRN ROCKIES
THURSDAY INTO THURSDAY NIGHT LEADING TO THE FRONT SAGGING SWD INTO
OUR NRN ZONES BEHIND THIS WAVE. THE GFS THEN KEEPS THIS FRONT IN THE
FAR NORTH PRETTY MUCH THROUGH THE PERIOD WITH SHARPLY COOLER TEMPS
BEHIND IT. THE ECMWF WASHES IT OUT EXCEPT MAYBE NEAR THE NRN BORDER
AS IT DEVELOPS AN INTENSE UPPER LOW OVER IDAHO ON SATURDAY THAT
LIFTS ACROSS THE PARK SATURDAY NIGHT WITH -4C AIR AT H7. LEANING
TOWARDS A STRONGER...SLOWER TROUGH...MAYBE NOT ECMWF STRONG...BUT
MORE TOWARDS THAT TIMING. WILL HAVE TO LOOK AT THIS AGAIN TONIGHT
AND HIT THE POPS MUCH HARDER IF THESE TRENDS CONTINUE AND THE MODELS
COME INTO BETTER AGREEMENT. POTENTIAL FOR A COLD LABOR DAY WEEKEND
WITH COLD RAIN AND MOUNTAIN SNOW IS STILL QUITE POSSIBLE IN THE
NORTHWEST PART OF WYOMING INCLUDING YELLOWSTONE NATIONAL PARK.
OTHERWISE...STILL WARM AND BREEZY TO WINDY AHEAD OF THE FRONT
THURSDAY AND IN THE SOUTH THROUGH AT LEAST FRIDAY BEFORE COOLER TO
COLDER AIR FILTERS IN. THE  WEST AND NORTH WILL SEE THE LONGEST
PERIOD OF COOLER WEATHER AND POTENTIALLY DOWNRIGHT COLD IN YNP OVER
THE WEEKEND.

&&

.AVIATION.../12Z ISSUANCE/

A COLD FRONT WILL PLUNGE SOUTH ACROSS NORTH AND CENTRAL WYOMING THROUGH 09Z.
GUSTY NORTH WIND AT 15 TO 25 KT WILL FOLLOW THE FRONT VCNTY AND
NORTH OF A KGEY TO KBYG LINE WITH WINDS NOT QUITE AS STRONG
FURTHER SOUTH. A FEW THUNDERSTORMS WILL ALSO CONTINUE VCNTY AND
SOUTH OF INTERSTATE 80 THROUGH 9Z. WINDS WILL DIMINISH BY 12Z.

ON MONDAY...ISOLATED TO WIDELY SCATTERED THUNDERSTORMS WILL DEVELOP MONDAY
AFTERNOON VCNTY OF A KRKS-KCPR LINE. SURFACE HIGH PRESSURE WILL
KEEP NORTHERN WYOMING UNDER PREVAILING SKC-FEW FL150-200
CONDITIONS AND S-SE WINDS AROUND 10KTS. THUNDERSTORM ACTIVITY WILL
MOSTLY END ACROSS THE SOUTH BY 3Z TUESDAY.

&&

.FIRE WEATHER...

IT WILL BE DRY TODAY BEHIND THIS MORNINGS COOL FRONT BUT A BIT
COOLER. THERE WILL BE SOME 20 MPH BREEZES IN THE AFTERNOON BUT RED
FLAG CONDITIONS ARE NOT EXPECTED. FOR THE REST OF THE WEEK THE
MINIMUM RELATIVE HUMIDITY WILL BE MAINLY IN THE TEENS AT THE LOWER
ELEVATIONS EAST OF THE DIVIDE AND 20S WEST. SOUTHWEST WINDS WILL
INCREASE WEDNESDAY OUT AHEAD OF THE NEXT DEVELOPING PACIFIC
TROUGH.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...NONE.

&&

$$

SHORT TERM...LIPSON
LONG TERM...PS
AVIATION...AEM
FIRE WEATHER...LIPSON




000
FXUS65 KRIW 310819
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
219 AM MDT MON AUG 31 2015

.SHORT TERM...TODAY THROUGH WEDNESDAY NIGHT

THE THUNDERSTORMS THAT OCCURRED EARLIER THIS EVENING WERE FAST MOVING
WITH HEAVY RAINFALL BUT WITH A SHORT RESIDENCE TIME AND FREQUENT
LIGHTNING ALONG WITH UP TO 40 MPH WIND GUSTS. THE FROPA AND
 HAS OCCURRED AND THE SHOWERS HAVE EXITED OFF TO THE EAST AND
DISSIPATED. CONFLUENT FLOW HAS TAKEN OVER. TODAY SOME INSTABILITY
WILL LINGER IN THE FAR SOUTH AND UP INTO SOUTHEAST NEUTRINO COUNTY
WHERE ISOLATED T STORMS ARE EXPECTED WITH SOME CONVECTION
STREAMING OFF THE UINTAS INTO SOUTHERN SWEETWATER COUNTY. ON
TUESDAY EXPECT ISOLD T STORMS ONLY IN THE NW MTNS WHEN CAPES
INCREASE SLIGHTLY BUT ARE NOT EXPECTED TO MOVE OFF THE MTNS.
WEDNESDAY WILL FEATURE INCREASE SOUTHWEST WINDS AS A CLOSED LOW
MOVES INLAND INTO BC AND THE ASCT TROUGH MAKES LANDFALL ONTO THE
PAC NW COAST THUS INCREASING OUR SOUTHWEST GRADIENT. TEMPS WILL BE
SLIGHTLY COOLER TODAY AND THEN BEGIN A WARMING TREND TUESDAY WITH
WEDNESDAY BEING THE WARMEST DAY OF THE PERIOD.

.LONG TERM...THURSDAY THROUGH MONDAY

MAJOR MEDIUM RANGE DIFFERENCES TONIGHT AS TO THE EVOLUTION OF OUR
LATE WEEK TROUGH. THE MODELS DO AGREE THAT THERE WILL BE A COLD
TROUGH OVER THE PACNW/NRN ROCKIES TO START THE PERIOD BUT HOW THIS
TROUGH TRANSLATES EWD WITH TIME IS WHERE THEY DEPART SIGNIFICANTLY.
THE GFS IS THE FASTEST TO MOVE THIS TROUGH OUT OF THE WAY BY
SATURDAY NIGHT WHILE THE ECMWF/GEM DON`T SWING THE TROUGH THROUGH
UNTIL MONDAY MORNING. THE FIRST SHORTWAVE THAT GETS KICKED OUT BY
THE DEVELOPING COLD TROUGH SHOULD LIFT NE ACROSS THE NRN ROCKIES
THURSDAY INTO THURSDAY NIGHT LEADING TO THE FRONT SAGGING SWD INTO
OUR NRN ZONES BEHIND THIS WAVE. THE GFS THEN KEEPS THIS FRONT IN THE
FAR NORTH PRETTY MUCH THROUGH THE PERIOD WITH SHARPLY COOLER TEMPS
BEHIND IT. THE ECMWF WASHES IT OUT EXCEPT MAYBE NEAR THE NRN BORDER
AS IT DEVELOPS AN INTENSE UPPER LOW OVER IDAHO ON SATURDAY THAT
LIFTS ACROSS THE PARK SATURDAY NIGHT WITH -4C AIR AT H7. LEANING
TOWARDS A STRONGER...SLOWER TROUGH...MAYBE NOT ECMWF STRONG...BUT
MORE TOWARDS THAT TIMING. WILL HAVE TO LOOK AT THIS AGAIN TONIGHT
AND HIT THE POPS MUCH HARDER IF THESE TRENDS CONTINUE AND THE MODELS
COME INTO BETTER AGREEMENT. POTENTIAL FOR A COLD LABOR DAY WEEKEND
WITH COLD RAIN AND MOUNTAIN SNOW IS STILL QUITE POSSIBLE IN THE
NORTHWEST PART OF WYOMING INCLUDING YELLOWSTONE NATIONAL PARK.
OTHERWISE...STILL WARM AND BREEZY TO WINDY AHEAD OF THE FRONT
THURSDAY AND IN THE SOUTH THROUGH AT LEAST FRIDAY BEFORE COOLER TO
COLDER AIR FILTERS IN. THE  WEST AND NORTH WILL SEE THE LONGEST
PERIOD OF COOLER WEATHER AND POTENTIALLY DOWNRIGHT COLD IN YNP OVER
THE WEEKEND.

&&

.AVIATION.../12Z ISSUANCE/

A COLD FRONT WILL PLUNGE SOUTH ACROSS NORTH AND CENTRAL WYOMING THROUGH 09Z.
GUSTY NORTH WIND AT 15 TO 25 KT WILL FOLLOW THE FRONT VCNTY AND
NORTH OF A KGEY TO KBYG LINE WITH WINDS NOT QUITE AS STRONG
FURTHER SOUTH. A FEW THUNDERSTORMS WILL ALSO CONTINUE VCNTY AND
SOUTH OF INTERSTATE 80 THROUGH 9Z. WINDS WILL DIMINISH BY 12Z.

ON MONDAY...ISOLATED TO WIDELY SCATTERED THUNDERSTORMS WILL DEVELOP MONDAY
AFTERNOON VCNTY OF A KRKS-KCPR LINE. SURFACE HIGH PRESSURE WILL
KEEP NORTHERN WYOMING UNDER PREVAILING SKC-FEW FL150-200
CONDITIONS AND S-SE WINDS AROUND 10KTS. THUNDERSTORM ACTIVITY WILL
MOSTLY END ACROSS THE SOUTH BY 3Z TUESDAY.

&&

.FIRE WEATHER...

IT WILL BE DRY TODAY BEHIND THIS MORNINGS COOL FRONT BUT A BIT
COOLER. THERE WILL BE SOME 20 MPH BREEZES IN THE AFTERNOON BUT RED
FLAG CONDITIONS ARE NOT EXPECTED. FOR THE REST OF THE WEEK THE
MINIMUM RELATIVE HUMIDITY WILL BE MAINLY IN THE TEENS AT THE LOWER
ELEVATIONS EAST OF THE DIVIDE AND 20S WEST. SOUTHWEST WINDS WILL
INCREASE WEDNESDAY OUT AHEAD OF THE NEXT DEVELOPING PACIFIC
TROUGH.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...NONE.

&&

$$

SHORT TERM...LIPSON
LONG TERM...PS
AVIATION...AEM
FIRE WEATHER...LIPSON




000
FXUS65 KRIW 310819
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
219 AM MDT MON AUG 31 2015

.SHORT TERM...TODAY THROUGH WEDNESDAY NIGHT

THE THUNDERSTORMS THAT OCCURRED EARLIER THIS EVENING WERE FAST MOVING
WITH HEAVY RAINFALL BUT WITH A SHORT RESIDENCE TIME AND FREQUENT
LIGHTNING ALONG WITH UP TO 40 MPH WIND GUSTS. THE FROPA AND
 HAS OCCURRED AND THE SHOWERS HAVE EXITED OFF TO THE EAST AND
DISSIPATED. CONFLUENT FLOW HAS TAKEN OVER. TODAY SOME INSTABILITY
WILL LINGER IN THE FAR SOUTH AND UP INTO SOUTHEAST NEUTRINO COUNTY
WHERE ISOLATED T STORMS ARE EXPECTED WITH SOME CONVECTION
STREAMING OFF THE UINTAS INTO SOUTHERN SWEETWATER COUNTY. ON
TUESDAY EXPECT ISOLD T STORMS ONLY IN THE NW MTNS WHEN CAPES
INCREASE SLIGHTLY BUT ARE NOT EXPECTED TO MOVE OFF THE MTNS.
WEDNESDAY WILL FEATURE INCREASE SOUTHWEST WINDS AS A CLOSED LOW
MOVES INLAND INTO BC AND THE ASCT TROUGH MAKES LANDFALL ONTO THE
PAC NW COAST THUS INCREASING OUR SOUTHWEST GRADIENT. TEMPS WILL BE
SLIGHTLY COOLER TODAY AND THEN BEGIN A WARMING TREND TUESDAY WITH
WEDNESDAY BEING THE WARMEST DAY OF THE PERIOD.

.LONG TERM...THURSDAY THROUGH MONDAY

MAJOR MEDIUM RANGE DIFFERENCES TONIGHT AS TO THE EVOLUTION OF OUR
LATE WEEK TROUGH. THE MODELS DO AGREE THAT THERE WILL BE A COLD
TROUGH OVER THE PACNW/NRN ROCKIES TO START THE PERIOD BUT HOW THIS
TROUGH TRANSLATES EWD WITH TIME IS WHERE THEY DEPART SIGNIFICANTLY.
THE GFS IS THE FASTEST TO MOVE THIS TROUGH OUT OF THE WAY BY
SATURDAY NIGHT WHILE THE ECMWF/GEM DON`T SWING THE TROUGH THROUGH
UNTIL MONDAY MORNING. THE FIRST SHORTWAVE THAT GETS KICKED OUT BY
THE DEVELOPING COLD TROUGH SHOULD LIFT NE ACROSS THE NRN ROCKIES
THURSDAY INTO THURSDAY NIGHT LEADING TO THE FRONT SAGGING SWD INTO
OUR NRN ZONES BEHIND THIS WAVE. THE GFS THEN KEEPS THIS FRONT IN THE
FAR NORTH PRETTY MUCH THROUGH THE PERIOD WITH SHARPLY COOLER TEMPS
BEHIND IT. THE ECMWF WASHES IT OUT EXCEPT MAYBE NEAR THE NRN BORDER
AS IT DEVELOPS AN INTENSE UPPER LOW OVER IDAHO ON SATURDAY THAT
LIFTS ACROSS THE PARK SATURDAY NIGHT WITH -4C AIR AT H7. LEANING
TOWARDS A STRONGER...SLOWER TROUGH...MAYBE NOT ECMWF STRONG...BUT
MORE TOWARDS THAT TIMING. WILL HAVE TO LOOK AT THIS AGAIN TONIGHT
AND HIT THE POPS MUCH HARDER IF THESE TRENDS CONTINUE AND THE MODELS
COME INTO BETTER AGREEMENT. POTENTIAL FOR A COLD LABOR DAY WEEKEND
WITH COLD RAIN AND MOUNTAIN SNOW IS STILL QUITE POSSIBLE IN THE
NORTHWEST PART OF WYOMING INCLUDING YELLOWSTONE NATIONAL PARK.
OTHERWISE...STILL WARM AND BREEZY TO WINDY AHEAD OF THE FRONT
THURSDAY AND IN THE SOUTH THROUGH AT LEAST FRIDAY BEFORE COOLER TO
COLDER AIR FILTERS IN. THE  WEST AND NORTH WILL SEE THE LONGEST
PERIOD OF COOLER WEATHER AND POTENTIALLY DOWNRIGHT COLD IN YNP OVER
THE WEEKEND.

&&

.AVIATION.../12Z ISSUANCE/

A COLD FRONT WILL PLUNGE SOUTH ACROSS NORTH AND CENTRAL WYOMING THROUGH 09Z.
GUSTY NORTH WIND AT 15 TO 25 KT WILL FOLLOW THE FRONT VCNTY AND
NORTH OF A KGEY TO KBYG LINE WITH WINDS NOT QUITE AS STRONG
FURTHER SOUTH. A FEW THUNDERSTORMS WILL ALSO CONTINUE VCNTY AND
SOUTH OF INTERSTATE 80 THROUGH 9Z. WINDS WILL DIMINISH BY 12Z.

ON MONDAY...ISOLATED TO WIDELY SCATTERED THUNDERSTORMS WILL DEVELOP MONDAY
AFTERNOON VCNTY OF A KRKS-KCPR LINE. SURFACE HIGH PRESSURE WILL
KEEP NORTHERN WYOMING UNDER PREVAILING SKC-FEW FL150-200
CONDITIONS AND S-SE WINDS AROUND 10KTS. THUNDERSTORM ACTIVITY WILL
MOSTLY END ACROSS THE SOUTH BY 3Z TUESDAY.

&&

.FIRE WEATHER...

IT WILL BE DRY TODAY BEHIND THIS MORNINGS COOL FRONT BUT A BIT
COOLER. THERE WILL BE SOME 20 MPH BREEZES IN THE AFTERNOON BUT RED
FLAG CONDITIONS ARE NOT EXPECTED. FOR THE REST OF THE WEEK THE
MINIMUM RELATIVE HUMIDITY WILL BE MAINLY IN THE TEENS AT THE LOWER
ELEVATIONS EAST OF THE DIVIDE AND 20S WEST. SOUTHWEST WINDS WILL
INCREASE WEDNESDAY OUT AHEAD OF THE NEXT DEVELOPING PACIFIC
TROUGH.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...NONE.

&&

$$

SHORT TERM...LIPSON
LONG TERM...PS
AVIATION...AEM
FIRE WEATHER...LIPSON




000
FXUS65 KRIW 310819
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
219 AM MDT MON AUG 31 2015

.SHORT TERM...TODAY THROUGH WEDNESDAY NIGHT

THE THUNDERSTORMS THAT OCCURRED EARLIER THIS EVENING WERE FAST MOVING
WITH HEAVY RAINFALL BUT WITH A SHORT RESIDENCE TIME AND FREQUENT
LIGHTNING ALONG WITH UP TO 40 MPH WIND GUSTS. THE FROPA AND
 HAS OCCURRED AND THE SHOWERS HAVE EXITED OFF TO THE EAST AND
DISSIPATED. CONFLUENT FLOW HAS TAKEN OVER. TODAY SOME INSTABILITY
WILL LINGER IN THE FAR SOUTH AND UP INTO SOUTHEAST NEUTRINO COUNTY
WHERE ISOLATED T STORMS ARE EXPECTED WITH SOME CONVECTION
STREAMING OFF THE UINTAS INTO SOUTHERN SWEETWATER COUNTY. ON
TUESDAY EXPECT ISOLD T STORMS ONLY IN THE NW MTNS WHEN CAPES
INCREASE SLIGHTLY BUT ARE NOT EXPECTED TO MOVE OFF THE MTNS.
WEDNESDAY WILL FEATURE INCREASE SOUTHWEST WINDS AS A CLOSED LOW
MOVES INLAND INTO BC AND THE ASCT TROUGH MAKES LANDFALL ONTO THE
PAC NW COAST THUS INCREASING OUR SOUTHWEST GRADIENT. TEMPS WILL BE
SLIGHTLY COOLER TODAY AND THEN BEGIN A WARMING TREND TUESDAY WITH
WEDNESDAY BEING THE WARMEST DAY OF THE PERIOD.

.LONG TERM...THURSDAY THROUGH MONDAY

MAJOR MEDIUM RANGE DIFFERENCES TONIGHT AS TO THE EVOLUTION OF OUR
LATE WEEK TROUGH. THE MODELS DO AGREE THAT THERE WILL BE A COLD
TROUGH OVER THE PACNW/NRN ROCKIES TO START THE PERIOD BUT HOW THIS
TROUGH TRANSLATES EWD WITH TIME IS WHERE THEY DEPART SIGNIFICANTLY.
THE GFS IS THE FASTEST TO MOVE THIS TROUGH OUT OF THE WAY BY
SATURDAY NIGHT WHILE THE ECMWF/GEM DON`T SWING THE TROUGH THROUGH
UNTIL MONDAY MORNING. THE FIRST SHORTWAVE THAT GETS KICKED OUT BY
THE DEVELOPING COLD TROUGH SHOULD LIFT NE ACROSS THE NRN ROCKIES
THURSDAY INTO THURSDAY NIGHT LEADING TO THE FRONT SAGGING SWD INTO
OUR NRN ZONES BEHIND THIS WAVE. THE GFS THEN KEEPS THIS FRONT IN THE
FAR NORTH PRETTY MUCH THROUGH THE PERIOD WITH SHARPLY COOLER TEMPS
BEHIND IT. THE ECMWF WASHES IT OUT EXCEPT MAYBE NEAR THE NRN BORDER
AS IT DEVELOPS AN INTENSE UPPER LOW OVER IDAHO ON SATURDAY THAT
LIFTS ACROSS THE PARK SATURDAY NIGHT WITH -4C AIR AT H7. LEANING
TOWARDS A STRONGER...SLOWER TROUGH...MAYBE NOT ECMWF STRONG...BUT
MORE TOWARDS THAT TIMING. WILL HAVE TO LOOK AT THIS AGAIN TONIGHT
AND HIT THE POPS MUCH HARDER IF THESE TRENDS CONTINUE AND THE MODELS
COME INTO BETTER AGREEMENT. POTENTIAL FOR A COLD LABOR DAY WEEKEND
WITH COLD RAIN AND MOUNTAIN SNOW IS STILL QUITE POSSIBLE IN THE
NORTHWEST PART OF WYOMING INCLUDING YELLOWSTONE NATIONAL PARK.
OTHERWISE...STILL WARM AND BREEZY TO WINDY AHEAD OF THE FRONT
THURSDAY AND IN THE SOUTH THROUGH AT LEAST FRIDAY BEFORE COOLER TO
COLDER AIR FILTERS IN. THE  WEST AND NORTH WILL SEE THE LONGEST
PERIOD OF COOLER WEATHER AND POTENTIALLY DOWNRIGHT COLD IN YNP OVER
THE WEEKEND.

&&

.AVIATION.../12Z ISSUANCE/

A COLD FRONT WILL PLUNGE SOUTH ACROSS NORTH AND CENTRAL WYOMING THROUGH 09Z.
GUSTY NORTH WIND AT 15 TO 25 KT WILL FOLLOW THE FRONT VCNTY AND
NORTH OF A KGEY TO KBYG LINE WITH WINDS NOT QUITE AS STRONG
FURTHER SOUTH. A FEW THUNDERSTORMS WILL ALSO CONTINUE VCNTY AND
SOUTH OF INTERSTATE 80 THROUGH 9Z. WINDS WILL DIMINISH BY 12Z.

ON MONDAY...ISOLATED TO WIDELY SCATTERED THUNDERSTORMS WILL DEVELOP MONDAY
AFTERNOON VCNTY OF A KRKS-KCPR LINE. SURFACE HIGH PRESSURE WILL
KEEP NORTHERN WYOMING UNDER PREVAILING SKC-FEW FL150-200
CONDITIONS AND S-SE WINDS AROUND 10KTS. THUNDERSTORM ACTIVITY WILL
MOSTLY END ACROSS THE SOUTH BY 3Z TUESDAY.

&&

.FIRE WEATHER...

IT WILL BE DRY TODAY BEHIND THIS MORNINGS COOL FRONT BUT A BIT
COOLER. THERE WILL BE SOME 20 MPH BREEZES IN THE AFTERNOON BUT RED
FLAG CONDITIONS ARE NOT EXPECTED. FOR THE REST OF THE WEEK THE
MINIMUM RELATIVE HUMIDITY WILL BE MAINLY IN THE TEENS AT THE LOWER
ELEVATIONS EAST OF THE DIVIDE AND 20S WEST. SOUTHWEST WINDS WILL
INCREASE WEDNESDAY OUT AHEAD OF THE NEXT DEVELOPING PACIFIC
TROUGH.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...NONE.

&&

$$

SHORT TERM...LIPSON
LONG TERM...PS
AVIATION...AEM
FIRE WEATHER...LIPSON




000
FXUS65 KRIW 310819
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
219 AM MDT MON AUG 31 2015

.SHORT TERM...TODAY THROUGH WEDNESDAY NIGHT

THE THUNDERSTORMS THAT OCCURRED EARLIER THIS EVENING WERE FAST MOVING
WITH HEAVY RAINFALL BUT WITH A SHORT RESIDENCE TIME AND FREQUENT
LIGHTNING ALONG WITH UP TO 40 MPH WIND GUSTS. THE FROPA AND
 HAS OCCURRED AND THE SHOWERS HAVE EXITED OFF TO THE EAST AND
DISSIPATED. CONFLUENT FLOW HAS TAKEN OVER. TODAY SOME INSTABILITY
WILL LINGER IN THE FAR SOUTH AND UP INTO SOUTHEAST NEUTRINO COUNTY
WHERE ISOLATED T STORMS ARE EXPECTED WITH SOME CONVECTION
STREAMING OFF THE UINTAS INTO SOUTHERN SWEETWATER COUNTY. ON
TUESDAY EXPECT ISOLD T STORMS ONLY IN THE NW MTNS WHEN CAPES
INCREASE SLIGHTLY BUT ARE NOT EXPECTED TO MOVE OFF THE MTNS.
WEDNESDAY WILL FEATURE INCREASE SOUTHWEST WINDS AS A CLOSED LOW
MOVES INLAND INTO BC AND THE ASCT TROUGH MAKES LANDFALL ONTO THE
PAC NW COAST THUS INCREASING OUR SOUTHWEST GRADIENT. TEMPS WILL BE
SLIGHTLY COOLER TODAY AND THEN BEGIN A WARMING TREND TUESDAY WITH
WEDNESDAY BEING THE WARMEST DAY OF THE PERIOD.

.LONG TERM...THURSDAY THROUGH MONDAY

MAJOR MEDIUM RANGE DIFFERENCES TONIGHT AS TO THE EVOLUTION OF OUR
LATE WEEK TROUGH. THE MODELS DO AGREE THAT THERE WILL BE A COLD
TROUGH OVER THE PACNW/NRN ROCKIES TO START THE PERIOD BUT HOW THIS
TROUGH TRANSLATES EWD WITH TIME IS WHERE THEY DEPART SIGNIFICANTLY.
THE GFS IS THE FASTEST TO MOVE THIS TROUGH OUT OF THE WAY BY
SATURDAY NIGHT WHILE THE ECMWF/GEM DON`T SWING THE TROUGH THROUGH
UNTIL MONDAY MORNING. THE FIRST SHORTWAVE THAT GETS KICKED OUT BY
THE DEVELOPING COLD TROUGH SHOULD LIFT NE ACROSS THE NRN ROCKIES
THURSDAY INTO THURSDAY NIGHT LEADING TO THE FRONT SAGGING SWD INTO
OUR NRN ZONES BEHIND THIS WAVE. THE GFS THEN KEEPS THIS FRONT IN THE
FAR NORTH PRETTY MUCH THROUGH THE PERIOD WITH SHARPLY COOLER TEMPS
BEHIND IT. THE ECMWF WASHES IT OUT EXCEPT MAYBE NEAR THE NRN BORDER
AS IT DEVELOPS AN INTENSE UPPER LOW OVER IDAHO ON SATURDAY THAT
LIFTS ACROSS THE PARK SATURDAY NIGHT WITH -4C AIR AT H7. LEANING
TOWARDS A STRONGER...SLOWER TROUGH...MAYBE NOT ECMWF STRONG...BUT
MORE TOWARDS THAT TIMING. WILL HAVE TO LOOK AT THIS AGAIN TONIGHT
AND HIT THE POPS MUCH HARDER IF THESE TRENDS CONTINUE AND THE MODELS
COME INTO BETTER AGREEMENT. POTENTIAL FOR A COLD LABOR DAY WEEKEND
WITH COLD RAIN AND MOUNTAIN SNOW IS STILL QUITE POSSIBLE IN THE
NORTHWEST PART OF WYOMING INCLUDING YELLOWSTONE NATIONAL PARK.
OTHERWISE...STILL WARM AND BREEZY TO WINDY AHEAD OF THE FRONT
THURSDAY AND IN THE SOUTH THROUGH AT LEAST FRIDAY BEFORE COOLER TO
COLDER AIR FILTERS IN. THE  WEST AND NORTH WILL SEE THE LONGEST
PERIOD OF COOLER WEATHER AND POTENTIALLY DOWNRIGHT COLD IN YNP OVER
THE WEEKEND.

&&

.AVIATION.../12Z ISSUANCE/

A COLD FRONT WILL PLUNGE SOUTH ACROSS NORTH AND CENTRAL WYOMING THROUGH 09Z.
GUSTY NORTH WIND AT 15 TO 25 KT WILL FOLLOW THE FRONT VCNTY AND
NORTH OF A KGEY TO KBYG LINE WITH WINDS NOT QUITE AS STRONG
FURTHER SOUTH. A FEW THUNDERSTORMS WILL ALSO CONTINUE VCNTY AND
SOUTH OF INTERSTATE 80 THROUGH 9Z. WINDS WILL DIMINISH BY 12Z.

ON MONDAY...ISOLATED TO WIDELY SCATTERED THUNDERSTORMS WILL DEVELOP MONDAY
AFTERNOON VCNTY OF A KRKS-KCPR LINE. SURFACE HIGH PRESSURE WILL
KEEP NORTHERN WYOMING UNDER PREVAILING SKC-FEW FL150-200
CONDITIONS AND S-SE WINDS AROUND 10KTS. THUNDERSTORM ACTIVITY WILL
MOSTLY END ACROSS THE SOUTH BY 3Z TUESDAY.

&&

.FIRE WEATHER...

IT WILL BE DRY TODAY BEHIND THIS MORNINGS COOL FRONT BUT A BIT
COOLER. THERE WILL BE SOME 20 MPH BREEZES IN THE AFTERNOON BUT RED
FLAG CONDITIONS ARE NOT EXPECTED. FOR THE REST OF THE WEEK THE
MINIMUM RELATIVE HUMIDITY WILL BE MAINLY IN THE TEENS AT THE LOWER
ELEVATIONS EAST OF THE DIVIDE AND 20S WEST. SOUTHWEST WINDS WILL
INCREASE WEDNESDAY OUT AHEAD OF THE NEXT DEVELOPING PACIFIC
TROUGH.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...NONE.

&&

$$

SHORT TERM...LIPSON
LONG TERM...PS
AVIATION...AEM
FIRE WEATHER...LIPSON




000
FXUS65 KRIW 310819 CCA
AFDRIW

AREA FORECAST DISCUSSION...CORRECTED
NATIONAL WEATHER SERVICE RIVERTON WY
219 AM MDT MON AUG 31 2015

.SHORT TERM...TODAY THROUGH WEDNESDAY NIGHT

THE THUNDERSTORMS THAT OCCURRED EARLIER THIS EVENING WERE FAST MOVING
WITH HEAVY RAINFALL BUT WITH A SHORT RESIDENCE TIME AND FREQUENT
LIGHTNING ALONG WITH UP TO 40 MPH WIND GUSTS. THE FROPA AND
HAS OCCURRED AND THE SHOWERS HAVE EXITED OFF TO THE EAST AND
DISSIPATED. CONFLUENT FLOW HAS TAKEN OVER. TODAY SOME INSTABILITY
WILL LINGER IN THE FAR SOUTH AND UP INTO SOUTHWEST NATRONA COUNTY
WHERE ISOLATED T STORMS ARE EXPECTED WITH SOME CONVECTION
STREAMING OFF THE UINTAS INTO SOUTHERN SWEETWATER COUNTY. ON
TUESDAY EXPECT ISOLD T STORMS ONLY IN THE NW MTNS WHEN CAPES
INCREASE SLIGHTLY BUT ARE NOT EXPECTED TO MOVE OFF THE MTNS.
WEDNESDAY WILL FEATURE INCREASE SOUTHWEST WINDS AS A CLOSED LOW
MOVES INLAND INTO BC AND THE ASCT TROUGH MAKES LANDFALL ONTO THE
PAC NW COAST THUS INCREASING OUR SOUTHWEST GRADIENT. TEMPS WILL BE
SLIGHTLY COOLER TODAY AND THEN BEGIN A WARMING TREND TUESDAY WITH
WEDNESDAY BEING THE WARMEST DAY OF THE PERIOD.

.LONG TERM...THURSDAY THROUGH MONDAY

MAJOR MEDIUM RANGE DIFFERENCES TONIGHT AS TO THE EVOLUTION OF OUR
LATE WEEK TROUGH. THE MODELS DO AGREE THAT THERE WILL BE A COLD
TROUGH OVER THE PACNW/NRN ROCKIES TO START THE PERIOD BUT HOW THIS
TROUGH TRANSLATES EWD WITH TIME IS WHERE THEY DEPART SIGNIFICANTLY.
THE GFS IS THE FASTEST TO MOVE THIS TROUGH OUT OF THE WAY BY
SATURDAY NIGHT WHILE THE ECMWF/GEM DON`T SWING THE TROUGH THROUGH
UNTIL MONDAY MORNING. THE FIRST SHORTWAVE THAT GETS KICKED OUT BY
THE DEVELOPING COLD TROUGH SHOULD LIFT NE ACROSS THE NRN ROCKIES
THURSDAY INTO THURSDAY NIGHT LEADING TO THE FRONT SAGGING SWD INTO
OUR NRN ZONES BEHIND THIS WAVE. THE GFS THEN KEEPS THIS FRONT IN THE
FAR NORTH PRETTY MUCH THROUGH THE PERIOD WITH SHARPLY COOLER TEMPS
BEHIND IT. THE ECMWF WASHES IT OUT EXCEPT MAYBE NEAR THE NRN BORDER
AS IT DEVELOPS AN INTENSE UPPER LOW OVER IDAHO ON SATURDAY THAT
LIFTS ACROSS THE PARK SATURDAY NIGHT WITH -4C AIR AT H7. LEANING
TOWARDS A STRONGER...SLOWER TROUGH...MAYBE NOT ECMWF STRONG...BUT
MORE TOWARDS THAT TIMING. WILL HAVE TO LOOK AT THIS AGAIN TONIGHT
AND HIT THE POPS MUCH HARDER IF THESE TRENDS CONTINUE AND THE MODELS
COME INTO BETTER AGREEMENT. POTENTIAL FOR A COLD LABOR DAY WEEKEND
WITH COLD RAIN AND MOUNTAIN SNOW IS STILL QUITE POSSIBLE IN THE
NORTHWEST PART OF WYOMING INCLUDING YELLOWSTONE NATIONAL PARK.
OTHERWISE...STILL WARM AND BREEZY TO WINDY AHEAD OF THE FRONT
THURSDAY AND IN THE SOUTH THROUGH AT LEAST FRIDAY BEFORE COOLER TO
COLDER AIR FILTERS IN. THE  WEST AND NORTH WILL SEE THE LONGEST
PERIOD OF COOLER WEATHER AND POTENTIALLY DOWNRIGHT COLD IN YNP OVER
THE WEEKEND.

&&

.AVIATION.../12Z ISSUANCE/

A COLD FRONT WILL PLUNGE SOUTH ACROSS NORTH AND CENTRAL WYOMING THROUGH 09Z.
GUSTY NORTH WIND AT 15 TO 25 KT WILL FOLLOW THE FRONT VCNTY AND
NORTH OF A KGEY TO KBYG LINE WITH WINDS NOT QUITE AS STRONG
FURTHER SOUTH. A FEW THUNDERSTORMS WILL ALSO CONTINUE VCNTY AND
SOUTH OF INTERSTATE 80 THROUGH 9Z. WINDS WILL DIMINISH BY 12Z.

ON MONDAY...ISOLATED TO WIDELY SCATTERED THUNDERSTORMS WILL DEVELOP MONDAY
AFTERNOON VCNTY OF A KRKS-KCPR LINE. SURFACE HIGH PRESSURE WILL
KEEP NORTHERN WYOMING UNDER PREVAILING SKC-FEW FL150-200
CONDITIONS AND S-SE WINDS AROUND 10KTS. THUNDERSTORM ACTIVITY WILL
MOSTLY END ACROSS THE SOUTH BY 3Z TUESDAY.

&&

.FIRE WEATHER...

IT WILL BE DRY TODAY BEHIND THIS MORNINGS COOL FRONT BUT A BIT
COOLER. THERE WILL BE SOME 20 MPH BREEZES IN THE AFTERNOON BUT RED
FLAG CONDITIONS ARE NOT EXPECTED. FOR THE REST OF THE WEEK THE
MINIMUM RELATIVE HUMIDITY WILL BE MAINLY IN THE TEENS AT THE LOWER
ELEVATIONS EAST OF THE DIVIDE AND 20S WEST. SOUTHWEST WINDS WILL
INCREASE WEDNESDAY OUT AHEAD OF THE NEXT DEVELOPING PACIFIC
TROUGH.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...NONE.

&&

$$

SHORT TERM...LIPSON
LONG TERM...PS
AVIATION...AEM
FIRE WEATHER...LIPSON



000
FXUS65 KRIW 310554
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
1152 PM MDT SUN AUG 30 2015

.UPDATE...AVIATION.../06Z ISSUANCE/

A COLD FRONT WILL PLUNGE SOUTH ACROSS NORTH AND CENTRAL WYOMING
THROUGH 09Z.  GUSTY NORTH WIND AT 15 TO 25 KT WILL FOLLOW THE FRONT
VCNTY AND NORTH OF A KGEY TO KBYG LINE WITH WINDS NOT QUITE AS
STRONG FURTHER SOUTH.  A FEW THUNDERSTORMS WILL ALSO CONTINUE VCNTY
AND SOUTH OF INTERSTATE 80 THROUGH 9Z.  WINDS WILL DIMINISH BY 12Z.

ON MONDAY...ISOLATED TO WIDELY SCATTERED THUNDERSTORMS WILL DEVELOP
MONDAY AFTERNOON VCNTY OF A KRKS-KCPR LINE.  SURFACE HIGH PRESSURE
WILL KEEP NORTHERN WYOMING UNDER PREVAILING SKC-FEW FL150-200
CONDITIONS AND S-SE WINDS AROUND 10KTS.  THUNDERSTORM ACTIVITY WILL
MOSTLY END ACROSS THE SOUTH BY 3Z TUESDAY.

 &&

.PREV DISCUSSION... /ISSUED 237 PM MDT SUN AUG 30 2015/

SHORT TERM...TONIGHT THROUGH MONDAY

A TROUGH AND COLD FRONT CONTINUE TO TRACK EASTWARD ACROSS THE
INTERMOUNTAIN WEST. THE COLD FRONT IS LYING NEAR THE MONTANA BORDER
AND IS EXPECTED TO SURGE SOUTHWARD AGAIN AROUND SUNSET WITH THE
MAIN PUSH ARRIVING TOWARD MIDNIGHT...THOUGH THE TIMING ON COLD
FRONTS CAN BE TRICKY AS THEY OFTEN MOVE FASTER THAN EXPECTED. WE
CAN CONTINUE TO EXPECT RED FLAG CONDITIONS SOUTH OF THE FRONT AND
MUCH COOLER AND MOIST CONDITIONS TO THE NORTH THROUGH THE EARLY
EVENING HOURS.

THERE IS ALSO SOME DECENT LIFT ON THE FRONT SIDE OF THIS TROUGH
WITH JET SUPPORT ALOFT...A THETA E RIDGE LYING APPROXIMATELY FROM
FLAMING GORGE TO KAYCEE...AND QG FORCING ARRIVING LATER IN THE
EVENING. AREAS WITH DECENT LOW LEVEL MOISTURE IN PLACE...ACROSS
THE WEST AND THE SOUTH...AND ON THE OTHER SIDE OF THE FRONT WILL
SEE WET THUNDERSTORMS AND AREAS LIKE THE SOUTHERN BIGHORN
BASIN...NATRONA COUNTY AND FREMONT COUNTY WILL SEE MAINLY DRY
THUNDERSTORMS THROUGH SUNSET...SHOWERS AND STORMS HAVE A BETTER
CHANCE OF PRODUCING A WETTING RAIN THEREAFTER.

MONDAY WILL BE DRY AGAIN BUT LESS WINDY AS WE LOSE THE GRADIENT AT
THE SURFACE AND ALOFT. TEMPERATURES WILL BE CLOSER TO SEASONAL
NORMS WITH HIGHS IN THE LOW TO MID 80S EAST...MID TO UPPER 70S
WEST AND SOUTH. A PLUME OF MOISTURE ACROSS COLORADO COULD BEGIN TO
POKE NORTH INTO SOUTHERN SWEETWATER COUNTY WITH A FEW STRAY
AFTERNOON STORMS POSSIBLE OTHERWISE IT WILL BE DRY AND RAIN FREE.

LONG TERM...MONDAY NIGHT THROUGH SUNDAY

MEDIUM-RANGE FORECAST MODELS ARE CONSISTENT AND AGAIN IN FAIRLY GOOD
AGREEMENT THROUGH THE FORECAST PERIOD. WEST-SOUTHWEST FLOW ALOFT ON
TUESDAY WILL BACK TO THE SOUTHWEST WEDNESDAY AND THURSDAY AS A
TROUGH DEEPENS OVER THE PACIFIC NORTHWEST. LIMITED MOISTURE IN
SOUTHWEST FLOW FOR TUESDAY...BUT SOME PRECIPITABLE WATER VALUES
AROUND 0.70 INCHES COULD LEAD TO WEAK CONVECTION IN JOHNSON AND
NATRONA COUNTIES. HOWEVER...WITH DEW POINTS IN THE 30S HAVE
CONTINUED A GENERALLY DRY FORECAST FOR NOW. SOUTHWEST FLOW ADVECTS
IN DRIER AIR FROM THE GREAT BASIN WEDNESDAY AND THURSDAY AND DO NOT
SEE MUCH IN THE WAY OF AVAILABLE MOISTURE FOR ANY CONVECTION.
SURFACE DEW POINTS WILL GENERALLY RANGE FROM 25-35F. ALSO...
WEDNESDAY LOOKS TO BE THE WARMEST DAY OF THE WEEK WITH TEMPERATURES
RUNNING ABOUT 5-10F ABOVE NORMAL AND THE NORTHERN BASINS PUSHING
INTO THE 90S AGAIN. THE COMBINATION OF THE UNSEASONABLY HOT
TEMPERATURES...LOW HUMIDITY...AND INCREASING SOUTHWEST WIND OF 15-30
MPH WILL VERY LIKELY LEAD TO CRITICAL FIRE WEATHER CONDITIONS FOR
WEDNESDAY AND MOST PROBABLY THURSDAY. MOST INTENSE WINDS WILL BE IN
THE CORRIDOR FROM ROCK SPRINGS TO CASPER. THOSE WITH FIRE WEATHER
INTERESTS SHOULD BE AWARE OF THE LIKELIHOOD OF THESE CONDITIONS FOR
WEDNESDAY AND THURSDAY AND BE ON THE ALERT FOR POSSIBLE HIGHLIGHTS ISSUED
EARLY THIS WEEK. FIRST UPPER LOW IN THE PACIFIC NORTHWEST TROUGH
WILL EJECT INTO ALBERTA THURSDAY. THIS UPPER LOW WILL QUICKLY BE
REPLACED BY ANOTHER SHORTWAVE THAT WILL DROP INTO THE BASE OF THE
TROUGH OVER THE INTERMOUNTAIN WEST FOR FRIDAY. UPPER FLOW WILL
PARALLEL SURFACE FRONT THAT WILL BE ORIENTED NORTHEAST-SOUTHWEST
JUST TO THE WEST OF WYOMING FOR FRIDAY. HAVE NUDGED TEMPERATURES
UP A TAD FOR FRIDAY AS IT DOES LOOK LIKE THE COOLER AIR WILL HANG
BACK ONE MORE DAY. AM STILL CONCERNED THAT FRIDAY MAY INDEED BE
WARMER THAN CURRENTLY FORECAST WITH COMPRESSIONAL WARMING AHEAD OF
THE APPROACHING FRONT/TROUGH. MOISTURE WILL RIDE ALONG OUR
NORTHWESTERN ZONES FOR FRIDAY AFTERNOON AND SATURDAY.
THEREFORE...HAVE INCREASED PRECIP CHANCES OVER YELLOWSTONE AND THE
SURROUNDING MOUNTAINS. ENERGY IN THE BASE OF THE TROUGH WILL BEGIN
TO EJECT SATURDAY WHILE AT THE SAME TIME A SURFACE LOW TAKES SHAPE
TO OUR SOUTHEAST. THIS WILL BRING THE COLD FRONT ACROSS THE
FORECAST AREA SATURDAY. BOTH THE ECMWF AND GFS HAVE THE FORECAST
AREA DRY SLOTTED SATURDAY AS THE UPPER LOW TRACKS TO OUR NORTH.
BEST CHANCE FOR MEASURABLE PRECIP OVER THE WEEKEND WILL BE ACROSS
THE NORTHERN THIRD OF THE FORECAST AREA CLOSEST TO THE UPPER LOW.
SURFACE HIGH PUSHES INTO WYOMING SUNDAY AND 700MB TEMPERATURES
FALL INTO THE ZERO TO +4C RANGE ACROSS THE NORTH. THIS WILL LEAD
TO COOLER THAN AVERAGE TEMPERATURES FOR SUNDAY IN ALL BUT
SOUTHWEST AND FAR WEST WYOMING.

AVIATION.../00Z ISSUANCE/

A COLD FRONT WILL CONTINUE TO PUSH EAST ACROSS THE INTERMOUNTAIN
WEST WITH SFC WINDS GENERALLY FROM THE SOUTHWEST TO WEST ACROSS MUCH
OF THE STATE AHEAD OF THE COLD FRONT...WINDS WILL BRIEFLY SWITCH TO
THE NW BEHIND THE FRONT WITH SOME AREAS OF 30-40KT GUSTS BEHIND THE
FRONT VCNTY KBYG KPOY KU68. THE MAIN AREA OF ISOLD-SCT -TSRA VCNTY
AND SOUTH OF A KEVW- KLND- KCPR LINE WITH HIGH BASED WINDY STORMS
EXPECTED INTO THE EARLY EVENING. THE COLD FRONT WILL BRING DRIER AIR
AND GUSTY WEST WIND INTO NW WYOMING MID TO LATE THIS
AFTERNOON...PUSHING ACROSS NORTH AND CENTRAL WYOMING LATE THIS
EVENING. CLEAR SKIES AND DIMINISHING WIND WILL PREVAIL ACROSS THE
AREA BEHIND THE FRONT EARLY MONDAY MORNING.

FIRE WEATHER...

..RED FLAG WARNING FOR PORTIONS OF CENTRAL AND NORTHERN WYOMING
THROUGH THE EVENING HOURS...

A COLD FRONT ASSOCIATED WITH THE TROUGH DIGGING TO THE WEST REMAINS
IN THE AREA NEAR THE MONTANA BORDER THIS AFTERNOON WITH COOLER
TEMPERATURES AND MODERATE HUMIDITY TO THE NORTH OF IT AND RED FLAG
TO NEAR RED FLAG CONDITIONS JUST TO THE SOUTH OF IT. MODELS ARE
CALLING FOR SOUTHWEST FLOW TO OVERTAKE THE FRONT AND CAUSE IT TO
RETREAT BACK NORTH FOR THE LATE AFTERNOON HOURS. THE MAIN FRONTAL
SURGE WILL COME LATER TONIGHT WITH STEADY 25 TO 35 MPH WINDS IN
JOHNSON COUNTY AND NORTHERN BIGHORN COUNTY BEHIND THE
FRONT...EXTENDED THE NORTHERN RED FLAG WARNINGS TO 3AM TO COVER THE
FRONTAL PASSAGE THOUGH IT MAY HAPPEN SOONER.

IN ADDITION...ISOLATED TO WIDELY SCATTERED MIXED WET AND DRY
THUNDERSTORMS ARE EXPECTED TO CONTINUE TO DEVELOP INTO THE EVENING
HOURS...WITH A FEW PERSISTING INTO THE NIGHT...ESPECIALLY EAST OF
THE DIVIDE.

IT WILL BE DRY BEHIND THE FRONT FOR MONDAY BUT A BIT COOLER. THERE
WILL BE SOME 20MPH BREEZES IN THE AFTERNOON BUT RED FLAG CONDITIONS
ARE NOT EXPECTED.

IT SILL LOOKS LIKE THERE COULD BE WIDESPREAD RED FLAG CONDITIONS MID
WEEK...STAY TUNED FOR UPDATES ON THE NEXT SYSTEM.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...
RED FLAG WARNING UNTIL 3 AM MDT MONDAY FOR WYZ275-276-281-282-
287.

&&

$$

UPDATE...AEM
SHORT TERM...ALLEN
LONG TERM...CNJ
AVIATION...AEM
FIRE WEATHER...ALLEN




000
FXUS65 KRIW 310554
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
1152 PM MDT SUN AUG 30 2015

.UPDATE...AVIATION.../06Z ISSUANCE/

A COLD FRONT WILL PLUNGE SOUTH ACROSS NORTH AND CENTRAL WYOMING
THROUGH 09Z.  GUSTY NORTH WIND AT 15 TO 25 KT WILL FOLLOW THE FRONT
VCNTY AND NORTH OF A KGEY TO KBYG LINE WITH WINDS NOT QUITE AS
STRONG FURTHER SOUTH.  A FEW THUNDERSTORMS WILL ALSO CONTINUE VCNTY
AND SOUTH OF INTERSTATE 80 THROUGH 9Z.  WINDS WILL DIMINISH BY 12Z.

ON MONDAY...ISOLATED TO WIDELY SCATTERED THUNDERSTORMS WILL DEVELOP
MONDAY AFTERNOON VCNTY OF A KRKS-KCPR LINE.  SURFACE HIGH PRESSURE
WILL KEEP NORTHERN WYOMING UNDER PREVAILING SKC-FEW FL150-200
CONDITIONS AND S-SE WINDS AROUND 10KTS.  THUNDERSTORM ACTIVITY WILL
MOSTLY END ACROSS THE SOUTH BY 3Z TUESDAY.

 &&

.PREV DISCUSSION... /ISSUED 237 PM MDT SUN AUG 30 2015/

SHORT TERM...TONIGHT THROUGH MONDAY

A TROUGH AND COLD FRONT CONTINUE TO TRACK EASTWARD ACROSS THE
INTERMOUNTAIN WEST. THE COLD FRONT IS LYING NEAR THE MONTANA BORDER
AND IS EXPECTED TO SURGE SOUTHWARD AGAIN AROUND SUNSET WITH THE
MAIN PUSH ARRIVING TOWARD MIDNIGHT...THOUGH THE TIMING ON COLD
FRONTS CAN BE TRICKY AS THEY OFTEN MOVE FASTER THAN EXPECTED. WE
CAN CONTINUE TO EXPECT RED FLAG CONDITIONS SOUTH OF THE FRONT AND
MUCH COOLER AND MOIST CONDITIONS TO THE NORTH THROUGH THE EARLY
EVENING HOURS.

THERE IS ALSO SOME DECENT LIFT ON THE FRONT SIDE OF THIS TROUGH
WITH JET SUPPORT ALOFT...A THETA E RIDGE LYING APPROXIMATELY FROM
FLAMING GORGE TO KAYCEE...AND QG FORCING ARRIVING LATER IN THE
EVENING. AREAS WITH DECENT LOW LEVEL MOISTURE IN PLACE...ACROSS
THE WEST AND THE SOUTH...AND ON THE OTHER SIDE OF THE FRONT WILL
SEE WET THUNDERSTORMS AND AREAS LIKE THE SOUTHERN BIGHORN
BASIN...NATRONA COUNTY AND FREMONT COUNTY WILL SEE MAINLY DRY
THUNDERSTORMS THROUGH SUNSET...SHOWERS AND STORMS HAVE A BETTER
CHANCE OF PRODUCING A WETTING RAIN THEREAFTER.

MONDAY WILL BE DRY AGAIN BUT LESS WINDY AS WE LOSE THE GRADIENT AT
THE SURFACE AND ALOFT. TEMPERATURES WILL BE CLOSER TO SEASONAL
NORMS WITH HIGHS IN THE LOW TO MID 80S EAST...MID TO UPPER 70S
WEST AND SOUTH. A PLUME OF MOISTURE ACROSS COLORADO COULD BEGIN TO
POKE NORTH INTO SOUTHERN SWEETWATER COUNTY WITH A FEW STRAY
AFTERNOON STORMS POSSIBLE OTHERWISE IT WILL BE DRY AND RAIN FREE.

LONG TERM...MONDAY NIGHT THROUGH SUNDAY

MEDIUM-RANGE FORECAST MODELS ARE CONSISTENT AND AGAIN IN FAIRLY GOOD
AGREEMENT THROUGH THE FORECAST PERIOD. WEST-SOUTHWEST FLOW ALOFT ON
TUESDAY WILL BACK TO THE SOUTHWEST WEDNESDAY AND THURSDAY AS A
TROUGH DEEPENS OVER THE PACIFIC NORTHWEST. LIMITED MOISTURE IN
SOUTHWEST FLOW FOR TUESDAY...BUT SOME PRECIPITABLE WATER VALUES
AROUND 0.70 INCHES COULD LEAD TO WEAK CONVECTION IN JOHNSON AND
NATRONA COUNTIES. HOWEVER...WITH DEW POINTS IN THE 30S HAVE
CONTINUED A GENERALLY DRY FORECAST FOR NOW. SOUTHWEST FLOW ADVECTS
IN DRIER AIR FROM THE GREAT BASIN WEDNESDAY AND THURSDAY AND DO NOT
SEE MUCH IN THE WAY OF AVAILABLE MOISTURE FOR ANY CONVECTION.
SURFACE DEW POINTS WILL GENERALLY RANGE FROM 25-35F. ALSO...
WEDNESDAY LOOKS TO BE THE WARMEST DAY OF THE WEEK WITH TEMPERATURES
RUNNING ABOUT 5-10F ABOVE NORMAL AND THE NORTHERN BASINS PUSHING
INTO THE 90S AGAIN. THE COMBINATION OF THE UNSEASONABLY HOT
TEMPERATURES...LOW HUMIDITY...AND INCREASING SOUTHWEST WIND OF 15-30
MPH WILL VERY LIKELY LEAD TO CRITICAL FIRE WEATHER CONDITIONS FOR
WEDNESDAY AND MOST PROBABLY THURSDAY. MOST INTENSE WINDS WILL BE IN
THE CORRIDOR FROM ROCK SPRINGS TO CASPER. THOSE WITH FIRE WEATHER
INTERESTS SHOULD BE AWARE OF THE LIKELIHOOD OF THESE CONDITIONS FOR
WEDNESDAY AND THURSDAY AND BE ON THE ALERT FOR POSSIBLE HIGHLIGHTS ISSUED
EARLY THIS WEEK. FIRST UPPER LOW IN THE PACIFIC NORTHWEST TROUGH
WILL EJECT INTO ALBERTA THURSDAY. THIS UPPER LOW WILL QUICKLY BE
REPLACED BY ANOTHER SHORTWAVE THAT WILL DROP INTO THE BASE OF THE
TROUGH OVER THE INTERMOUNTAIN WEST FOR FRIDAY. UPPER FLOW WILL
PARALLEL SURFACE FRONT THAT WILL BE ORIENTED NORTHEAST-SOUTHWEST
JUST TO THE WEST OF WYOMING FOR FRIDAY. HAVE NUDGED TEMPERATURES
UP A TAD FOR FRIDAY AS IT DOES LOOK LIKE THE COOLER AIR WILL HANG
BACK ONE MORE DAY. AM STILL CONCERNED THAT FRIDAY MAY INDEED BE
WARMER THAN CURRENTLY FORECAST WITH COMPRESSIONAL WARMING AHEAD OF
THE APPROACHING FRONT/TROUGH. MOISTURE WILL RIDE ALONG OUR
NORTHWESTERN ZONES FOR FRIDAY AFTERNOON AND SATURDAY.
THEREFORE...HAVE INCREASED PRECIP CHANCES OVER YELLOWSTONE AND THE
SURROUNDING MOUNTAINS. ENERGY IN THE BASE OF THE TROUGH WILL BEGIN
TO EJECT SATURDAY WHILE AT THE SAME TIME A SURFACE LOW TAKES SHAPE
TO OUR SOUTHEAST. THIS WILL BRING THE COLD FRONT ACROSS THE
FORECAST AREA SATURDAY. BOTH THE ECMWF AND GFS HAVE THE FORECAST
AREA DRY SLOTTED SATURDAY AS THE UPPER LOW TRACKS TO OUR NORTH.
BEST CHANCE FOR MEASURABLE PRECIP OVER THE WEEKEND WILL BE ACROSS
THE NORTHERN THIRD OF THE FORECAST AREA CLOSEST TO THE UPPER LOW.
SURFACE HIGH PUSHES INTO WYOMING SUNDAY AND 700MB TEMPERATURES
FALL INTO THE ZERO TO +4C RANGE ACROSS THE NORTH. THIS WILL LEAD
TO COOLER THAN AVERAGE TEMPERATURES FOR SUNDAY IN ALL BUT
SOUTHWEST AND FAR WEST WYOMING.

AVIATION.../00Z ISSUANCE/

A COLD FRONT WILL CONTINUE TO PUSH EAST ACROSS THE INTERMOUNTAIN
WEST WITH SFC WINDS GENERALLY FROM THE SOUTHWEST TO WEST ACROSS MUCH
OF THE STATE AHEAD OF THE COLD FRONT...WINDS WILL BRIEFLY SWITCH TO
THE NW BEHIND THE FRONT WITH SOME AREAS OF 30-40KT GUSTS BEHIND THE
FRONT VCNTY KBYG KPOY KU68. THE MAIN AREA OF ISOLD-SCT -TSRA VCNTY
AND SOUTH OF A KEVW- KLND- KCPR LINE WITH HIGH BASED WINDY STORMS
EXPECTED INTO THE EARLY EVENING. THE COLD FRONT WILL BRING DRIER AIR
AND GUSTY WEST WIND INTO NW WYOMING MID TO LATE THIS
AFTERNOON...PUSHING ACROSS NORTH AND CENTRAL WYOMING LATE THIS
EVENING. CLEAR SKIES AND DIMINISHING WIND WILL PREVAIL ACROSS THE
AREA BEHIND THE FRONT EARLY MONDAY MORNING.

FIRE WEATHER...

..RED FLAG WARNING FOR PORTIONS OF CENTRAL AND NORTHERN WYOMING
THROUGH THE EVENING HOURS...

A COLD FRONT ASSOCIATED WITH THE TROUGH DIGGING TO THE WEST REMAINS
IN THE AREA NEAR THE MONTANA BORDER THIS AFTERNOON WITH COOLER
TEMPERATURES AND MODERATE HUMIDITY TO THE NORTH OF IT AND RED FLAG
TO NEAR RED FLAG CONDITIONS JUST TO THE SOUTH OF IT. MODELS ARE
CALLING FOR SOUTHWEST FLOW TO OVERTAKE THE FRONT AND CAUSE IT TO
RETREAT BACK NORTH FOR THE LATE AFTERNOON HOURS. THE MAIN FRONTAL
SURGE WILL COME LATER TONIGHT WITH STEADY 25 TO 35 MPH WINDS IN
JOHNSON COUNTY AND NORTHERN BIGHORN COUNTY BEHIND THE
FRONT...EXTENDED THE NORTHERN RED FLAG WARNINGS TO 3AM TO COVER THE
FRONTAL PASSAGE THOUGH IT MAY HAPPEN SOONER.

IN ADDITION...ISOLATED TO WIDELY SCATTERED MIXED WET AND DRY
THUNDERSTORMS ARE EXPECTED TO CONTINUE TO DEVELOP INTO THE EVENING
HOURS...WITH A FEW PERSISTING INTO THE NIGHT...ESPECIALLY EAST OF
THE DIVIDE.

IT WILL BE DRY BEHIND THE FRONT FOR MONDAY BUT A BIT COOLER. THERE
WILL BE SOME 20MPH BREEZES IN THE AFTERNOON BUT RED FLAG CONDITIONS
ARE NOT EXPECTED.

IT SILL LOOKS LIKE THERE COULD BE WIDESPREAD RED FLAG CONDITIONS MID
WEEK...STAY TUNED FOR UPDATES ON THE NEXT SYSTEM.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...
RED FLAG WARNING UNTIL 3 AM MDT MONDAY FOR WYZ275-276-281-282-
287.

&&

$$

UPDATE...AEM
SHORT TERM...ALLEN
LONG TERM...CNJ
AVIATION...AEM
FIRE WEATHER...ALLEN



000
FXUS63 KUNR 310541
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
1141 PM MDT SUN AUG 30 2015

.UPDATE...
ISSUED AT 802 PM MDT SUN AUG 30 2015

01Z SURFACE ANALYSIS HAD FRONTAL BOUNDARY FROM CENTRAL ND INTO
CENTRAL WY WITH PREFRONTAL TROUGH FROM CENTRAL ND INTO WESTERN NE.
DEEP DAYTIME MIXING ALONG WITH INCREASE IN MID-LEVEL MOISTURE PER
WATER VAPOUR RESULTED IN MAINLY HIGH-BASED -SHRA/-TSRA ALONG THE
FRONTAL BOUNDARY THIS EVENING...WHICH ARE NOW MOVING NORTHEAST
UNDER MEAN FLOW ALOFT. ACTIVITY WILL SLOWLY WANE OVERNIGHT. UPDATE
TO ADDRESS LATEST TRENDS IN TIMING.

&&

.SHORT TERM...THIS EVENING THROUGH MONDAY NIGHT
ISSUED AT 300 PM MDT SUN AUG 30 2015

CURRENT SURFACE ANALYSIS SHOWS SLOW MOVING COLD FRONT FROM FAR
EASTERN MT THROUGH NORTHEAST INTO CENTRAL WY. UPPER LEVEL ANALYSIS
SHOWS POSITIVELY TILTED RIDGE FROM THE SOUTHERN ROCKIES INTO
EASTERN PORTIONS OF THE NORTHERN PLAINS. SOUTHWEST FLOW ALOFT
BEHIND THE RIDGE FROM THE GREAT BASIN TO THE NORTHERN HIGH PLAINS.
SKIES ARE MOSTLY SUNNY ACROSS EASTERN PORTIONS OF THE CWA...PARTLY
CLOUDY OVER NORTHEAST WY. REGIONAL RADARS SHOW BULK OF SHOWER AND
THUNDERSTORM ACTIVITY OVER NORTHEAST MT INTO NORTHWEST ND NEAR THE
FRONT...AS WELL AS OVER THE HIGHER TERRAIN OF CENTRAL WY. A FEW
SHOWERS AND STORMS ARE NOW DEVELOPING NEAR AND AHEAD OF THE FRONT
OVER NORTHEAST WY. TEMPS ARE IN THE 90S OVER MUCH OF THE
AREA...WITH SOME 80S OVER THE BLACK HILLS. WINDS ARE FROM THE
SOUTH TO SOUTHWEST... BREEZY OVER SOUTH CENTRAL SD AS WELL AS
PORTIONS OF NORTHEAST WY.

COLD FRONT WILL EVER SO SLOWLY CROSS THE FORECAST AREA LATE TODAY
AND TONIGHT...WEAKENING SOME AS IT REACHES SOUTH CENTRAL SD MONDAY
MORNING. MOSTLY ISOLATED SHOWERS AND THUNDERSTORMS CAN BE EXPECTED
WITH THE FRONTAL PASSAGE TONIGHT. THE BEST CHANCES WILL LIKELY BE
OVER FAR NORTHWEST SD THIS EVENING. THE THREAT FOR ANY STRONGER
STORMS WILL BE MINIMAL THROUGH THE EVENING AS CAPE VALUES REMAIN
RELATIVELY LOW ACROSS THE AREA...BUT SOME GUSTY WINDS ARE POSSIBLE.
WINDS WILL SWITCH TO THE WEST AND NORTHWEST BEHIND THE
FRONT...BECOMING BREEZY LATER TONIGHT AND EARLY MONDAY OVER MUCH OF
THE PLAINS. AHEAD OF THE FRONT...WINDS WILL REMAIN BREEZY FROM THE
SOUTH OVER SOUTH CENTRAL SD. LOWS WILL RANGE FROM THE 50S OVER
NORTHEAST WY AND THE BLACK HILLS TO AROUND 70 OVER SOUTH CENTRAL SD.

FRONT WILL SLOWLY SAG SOUTH AND EAST OF THE AREA ON MONDAY AND
FURTHER WEAKEN. WOULD NOT BE SURPRISED TO SEE A SHOWER OR
THUNDERSTORM OVER FAR SOUTHERN SD ON MONDAY IN CLOSER VICINITY TO
THE FRONT...ESPECIALLY SOUTH CENTRAL SD...BUT CHANCES LOOK BELOW 15
PERCENT SO WILL LEAVE FORECAST DRY. SOME COOLER AIR WILL BUILD INTO
THE AREA...WITH HIGHS IN THE 80S ACROSS THE PLAINS...70S IN THE
BLACK HILLS. BRISK NORTHWEST WINDS CAN BE EXPECTED ACROSS THE SD
PLAINS DURING THE DAY. MOSTLY CLEAR MONDAY NIGHT WITH LOWS NEAR OR
SLIGHTLY ABOVE SEASONAL AVERAGES.

.LONG TERM...TUESDAY THROUGH SUNDAY
ISSUED AT 300 PM MDT SUN AUG 30 2015

LONG WAVE TROUGH OVER WESTERN NOAM WILL REMAIN THROUGH
MID WEEK...WITH EVENTUAL BREAKDOWN PER AN ADVECTING STRONG NORTHERN
PAC IMPULSE. THIS WILL SUPPORT VERY WARM TEMPS THROUGH THURS. STRONG
SUPPORT AMONG DETERMINISTIC AND ENSEMBLE MODEL RUNS FOR A STRONG
COLD FRONT TO ADVECT TROUGH THE REGION NEXT WEEKEND AS THE PAC NW
UPPER TROUGH MERGES WITH A STRONG CENTRAL CANADIAN TROUGH.
HOWEVER...PRECIP CHANCES STILL LOOK LOW GIVEN LACK OF SUFFICIENT
MOISTURE WITH THE BULK OF LSA SHIFTING NORTH OF THE AREA. MUCH
COOLER TEMPS LOOK MORE LIKELY BY SUN-MON NEXT WEEK WITH HIGHS IN THE
50S-60S POSSIBLE BY THEN. MEANWHILE...DRY WEATHER IS EXPECTED TUE-
THUR...ALTHOUGH A WEAK SIGNAL REMAINS OVER SCENTRAL SD TUES WHERE A
LL TROUGH AND MOISTURE ADV ARE PROGGED. DID BUMPS TEMPS UP TUE-THUR
GIVEN WARM-DRY SW FLOW WITH WARMER TEMPS NOW PROGGED IN CONSENSUS
BLENDS. OTHERWISE...COOLER CONDS WILL ARRIVE FRI-SAT...HOW COOL WILL
DEPEND ON THE PROGRESSIVE NATURE OF THE UPPER TROUGH...WHICH IS A
LITTLE SLOWER IN THE ECMWF. MUCH COOLER CONDS EXPECTED BY EARLY NEXT
WEEK...ALONG WITH ISOLD-SCT SHRA.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1140 PM MDT SUN AUG 30 2015

A COOL FRONT WILL SLOWLY SLIDE SOUTHEAST THROUGH THE CWA INTO
MONDAY MORNING. GUSTY SOUTHERLY WINDS ARE EXPECTED AHEAD OF IT
WITH GUSTY NORTHWEST WINDS BEHIND IT. LEFTOVER -TSRA WILL END BY
12Z. VFR CIGS/VSBYS ARE EXPECTED THROUGH THE PERIOD.

&&

.FIRE WEATHER...
ISSUED AT 300 PM MDT SUN AUG 30 2015

WARM AND DRY CONDITIONS WILL PERSIST ACROSS NE WY THIS
AFTERNOON...WITH RELATIVE HUMIDITY AROUND 15 PERCENT AND GUSTY
WESTERLY WINDS OF 20 TO 30 MPH. A FEW ISOLD TS ARE ALSO POSSIBLE
WITH DRY LIGHTNING AND GUSTY WINDS LIKELY WITH ANY TS. A COLD
FRONT WILL CROSS THE AREA TONIGHT WITH WINDS SHIFTING NW AND
REMAINING GUSTY FOR A FEW HOURS.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
WY...NONE.
&&

$$

UPDATE...HELGESON
SHORT TERM...26
LONG TERM...JC
AVIATION...HELGESON
FIRE WEATHER...JC




000
FXUS63 KUNR 310541
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
1141 PM MDT SUN AUG 30 2015

.UPDATE...
ISSUED AT 802 PM MDT SUN AUG 30 2015

01Z SURFACE ANALYSIS HAD FRONTAL BOUNDARY FROM CENTRAL ND INTO
CENTRAL WY WITH PREFRONTAL TROUGH FROM CENTRAL ND INTO WESTERN NE.
DEEP DAYTIME MIXING ALONG WITH INCREASE IN MID-LEVEL MOISTURE PER
WATER VAPOUR RESULTED IN MAINLY HIGH-BASED -SHRA/-TSRA ALONG THE
FRONTAL BOUNDARY THIS EVENING...WHICH ARE NOW MOVING NORTHEAST
UNDER MEAN FLOW ALOFT. ACTIVITY WILL SLOWLY WANE OVERNIGHT. UPDATE
TO ADDRESS LATEST TRENDS IN TIMING.

&&

.SHORT TERM...THIS EVENING THROUGH MONDAY NIGHT
ISSUED AT 300 PM MDT SUN AUG 30 2015

CURRENT SURFACE ANALYSIS SHOWS SLOW MOVING COLD FRONT FROM FAR
EASTERN MT THROUGH NORTHEAST INTO CENTRAL WY. UPPER LEVEL ANALYSIS
SHOWS POSITIVELY TILTED RIDGE FROM THE SOUTHERN ROCKIES INTO
EASTERN PORTIONS OF THE NORTHERN PLAINS. SOUTHWEST FLOW ALOFT
BEHIND THE RIDGE FROM THE GREAT BASIN TO THE NORTHERN HIGH PLAINS.
SKIES ARE MOSTLY SUNNY ACROSS EASTERN PORTIONS OF THE CWA...PARTLY
CLOUDY OVER NORTHEAST WY. REGIONAL RADARS SHOW BULK OF SHOWER AND
THUNDERSTORM ACTIVITY OVER NORTHEAST MT INTO NORTHWEST ND NEAR THE
FRONT...AS WELL AS OVER THE HIGHER TERRAIN OF CENTRAL WY. A FEW
SHOWERS AND STORMS ARE NOW DEVELOPING NEAR AND AHEAD OF THE FRONT
OVER NORTHEAST WY. TEMPS ARE IN THE 90S OVER MUCH OF THE
AREA...WITH SOME 80S OVER THE BLACK HILLS. WINDS ARE FROM THE
SOUTH TO SOUTHWEST... BREEZY OVER SOUTH CENTRAL SD AS WELL AS
PORTIONS OF NORTHEAST WY.

COLD FRONT WILL EVER SO SLOWLY CROSS THE FORECAST AREA LATE TODAY
AND TONIGHT...WEAKENING SOME AS IT REACHES SOUTH CENTRAL SD MONDAY
MORNING. MOSTLY ISOLATED SHOWERS AND THUNDERSTORMS CAN BE EXPECTED
WITH THE FRONTAL PASSAGE TONIGHT. THE BEST CHANCES WILL LIKELY BE
OVER FAR NORTHWEST SD THIS EVENING. THE THREAT FOR ANY STRONGER
STORMS WILL BE MINIMAL THROUGH THE EVENING AS CAPE VALUES REMAIN
RELATIVELY LOW ACROSS THE AREA...BUT SOME GUSTY WINDS ARE POSSIBLE.
WINDS WILL SWITCH TO THE WEST AND NORTHWEST BEHIND THE
FRONT...BECOMING BREEZY LATER TONIGHT AND EARLY MONDAY OVER MUCH OF
THE PLAINS. AHEAD OF THE FRONT...WINDS WILL REMAIN BREEZY FROM THE
SOUTH OVER SOUTH CENTRAL SD. LOWS WILL RANGE FROM THE 50S OVER
NORTHEAST WY AND THE BLACK HILLS TO AROUND 70 OVER SOUTH CENTRAL SD.

FRONT WILL SLOWLY SAG SOUTH AND EAST OF THE AREA ON MONDAY AND
FURTHER WEAKEN. WOULD NOT BE SURPRISED TO SEE A SHOWER OR
THUNDERSTORM OVER FAR SOUTHERN SD ON MONDAY IN CLOSER VICINITY TO
THE FRONT...ESPECIALLY SOUTH CENTRAL SD...BUT CHANCES LOOK BELOW 15
PERCENT SO WILL LEAVE FORECAST DRY. SOME COOLER AIR WILL BUILD INTO
THE AREA...WITH HIGHS IN THE 80S ACROSS THE PLAINS...70S IN THE
BLACK HILLS. BRISK NORTHWEST WINDS CAN BE EXPECTED ACROSS THE SD
PLAINS DURING THE DAY. MOSTLY CLEAR MONDAY NIGHT WITH LOWS NEAR OR
SLIGHTLY ABOVE SEASONAL AVERAGES.

.LONG TERM...TUESDAY THROUGH SUNDAY
ISSUED AT 300 PM MDT SUN AUG 30 2015

LONG WAVE TROUGH OVER WESTERN NOAM WILL REMAIN THROUGH
MID WEEK...WITH EVENTUAL BREAKDOWN PER AN ADVECTING STRONG NORTHERN
PAC IMPULSE. THIS WILL SUPPORT VERY WARM TEMPS THROUGH THURS. STRONG
SUPPORT AMONG DETERMINISTIC AND ENSEMBLE MODEL RUNS FOR A STRONG
COLD FRONT TO ADVECT TROUGH THE REGION NEXT WEEKEND AS THE PAC NW
UPPER TROUGH MERGES WITH A STRONG CENTRAL CANADIAN TROUGH.
HOWEVER...PRECIP CHANCES STILL LOOK LOW GIVEN LACK OF SUFFICIENT
MOISTURE WITH THE BULK OF LSA SHIFTING NORTH OF THE AREA. MUCH
COOLER TEMPS LOOK MORE LIKELY BY SUN-MON NEXT WEEK WITH HIGHS IN THE
50S-60S POSSIBLE BY THEN. MEANWHILE...DRY WEATHER IS EXPECTED TUE-
THUR...ALTHOUGH A WEAK SIGNAL REMAINS OVER SCENTRAL SD TUES WHERE A
LL TROUGH AND MOISTURE ADV ARE PROGGED. DID BUMPS TEMPS UP TUE-THUR
GIVEN WARM-DRY SW FLOW WITH WARMER TEMPS NOW PROGGED IN CONSENSUS
BLENDS. OTHERWISE...COOLER CONDS WILL ARRIVE FRI-SAT...HOW COOL WILL
DEPEND ON THE PROGRESSIVE NATURE OF THE UPPER TROUGH...WHICH IS A
LITTLE SLOWER IN THE ECMWF. MUCH COOLER CONDS EXPECTED BY EARLY NEXT
WEEK...ALONG WITH ISOLD-SCT SHRA.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1140 PM MDT SUN AUG 30 2015

A COOL FRONT WILL SLOWLY SLIDE SOUTHEAST THROUGH THE CWA INTO
MONDAY MORNING. GUSTY SOUTHERLY WINDS ARE EXPECTED AHEAD OF IT
WITH GUSTY NORTHWEST WINDS BEHIND IT. LEFTOVER -TSRA WILL END BY
12Z. VFR CIGS/VSBYS ARE EXPECTED THROUGH THE PERIOD.

&&

.FIRE WEATHER...
ISSUED AT 300 PM MDT SUN AUG 30 2015

WARM AND DRY CONDITIONS WILL PERSIST ACROSS NE WY THIS
AFTERNOON...WITH RELATIVE HUMIDITY AROUND 15 PERCENT AND GUSTY
WESTERLY WINDS OF 20 TO 30 MPH. A FEW ISOLD TS ARE ALSO POSSIBLE
WITH DRY LIGHTNING AND GUSTY WINDS LIKELY WITH ANY TS. A COLD
FRONT WILL CROSS THE AREA TONIGHT WITH WINDS SHIFTING NW AND
REMAINING GUSTY FOR A FEW HOURS.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
WY...NONE.
&&

$$

UPDATE...HELGESON
SHORT TERM...26
LONG TERM...JC
AVIATION...HELGESON
FIRE WEATHER...JC




000
FXUS63 KUNR 310541
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
1141 PM MDT SUN AUG 30 2015

.UPDATE...
ISSUED AT 802 PM MDT SUN AUG 30 2015

01Z SURFACE ANALYSIS HAD FRONTAL BOUNDARY FROM CENTRAL ND INTO
CENTRAL WY WITH PREFRONTAL TROUGH FROM CENTRAL ND INTO WESTERN NE.
DEEP DAYTIME MIXING ALONG WITH INCREASE IN MID-LEVEL MOISTURE PER
WATER VAPOUR RESULTED IN MAINLY HIGH-BASED -SHRA/-TSRA ALONG THE
FRONTAL BOUNDARY THIS EVENING...WHICH ARE NOW MOVING NORTHEAST
UNDER MEAN FLOW ALOFT. ACTIVITY WILL SLOWLY WANE OVERNIGHT. UPDATE
TO ADDRESS LATEST TRENDS IN TIMING.

&&

.SHORT TERM...THIS EVENING THROUGH MONDAY NIGHT
ISSUED AT 300 PM MDT SUN AUG 30 2015

CURRENT SURFACE ANALYSIS SHOWS SLOW MOVING COLD FRONT FROM FAR
EASTERN MT THROUGH NORTHEAST INTO CENTRAL WY. UPPER LEVEL ANALYSIS
SHOWS POSITIVELY TILTED RIDGE FROM THE SOUTHERN ROCKIES INTO
EASTERN PORTIONS OF THE NORTHERN PLAINS. SOUTHWEST FLOW ALOFT
BEHIND THE RIDGE FROM THE GREAT BASIN TO THE NORTHERN HIGH PLAINS.
SKIES ARE MOSTLY SUNNY ACROSS EASTERN PORTIONS OF THE CWA...PARTLY
CLOUDY OVER NORTHEAST WY. REGIONAL RADARS SHOW BULK OF SHOWER AND
THUNDERSTORM ACTIVITY OVER NORTHEAST MT INTO NORTHWEST ND NEAR THE
FRONT...AS WELL AS OVER THE HIGHER TERRAIN OF CENTRAL WY. A FEW
SHOWERS AND STORMS ARE NOW DEVELOPING NEAR AND AHEAD OF THE FRONT
OVER NORTHEAST WY. TEMPS ARE IN THE 90S OVER MUCH OF THE
AREA...WITH SOME 80S OVER THE BLACK HILLS. WINDS ARE FROM THE
SOUTH TO SOUTHWEST... BREEZY OVER SOUTH CENTRAL SD AS WELL AS
PORTIONS OF NORTHEAST WY.

COLD FRONT WILL EVER SO SLOWLY CROSS THE FORECAST AREA LATE TODAY
AND TONIGHT...WEAKENING SOME AS IT REACHES SOUTH CENTRAL SD MONDAY
MORNING. MOSTLY ISOLATED SHOWERS AND THUNDERSTORMS CAN BE EXPECTED
WITH THE FRONTAL PASSAGE TONIGHT. THE BEST CHANCES WILL LIKELY BE
OVER FAR NORTHWEST SD THIS EVENING. THE THREAT FOR ANY STRONGER
STORMS WILL BE MINIMAL THROUGH THE EVENING AS CAPE VALUES REMAIN
RELATIVELY LOW ACROSS THE AREA...BUT SOME GUSTY WINDS ARE POSSIBLE.
WINDS WILL SWITCH TO THE WEST AND NORTHWEST BEHIND THE
FRONT...BECOMING BREEZY LATER TONIGHT AND EARLY MONDAY OVER MUCH OF
THE PLAINS. AHEAD OF THE FRONT...WINDS WILL REMAIN BREEZY FROM THE
SOUTH OVER SOUTH CENTRAL SD. LOWS WILL RANGE FROM THE 50S OVER
NORTHEAST WY AND THE BLACK HILLS TO AROUND 70 OVER SOUTH CENTRAL SD.

FRONT WILL SLOWLY SAG SOUTH AND EAST OF THE AREA ON MONDAY AND
FURTHER WEAKEN. WOULD NOT BE SURPRISED TO SEE A SHOWER OR
THUNDERSTORM OVER FAR SOUTHERN SD ON MONDAY IN CLOSER VICINITY TO
THE FRONT...ESPECIALLY SOUTH CENTRAL SD...BUT CHANCES LOOK BELOW 15
PERCENT SO WILL LEAVE FORECAST DRY. SOME COOLER AIR WILL BUILD INTO
THE AREA...WITH HIGHS IN THE 80S ACROSS THE PLAINS...70S IN THE
BLACK HILLS. BRISK NORTHWEST WINDS CAN BE EXPECTED ACROSS THE SD
PLAINS DURING THE DAY. MOSTLY CLEAR MONDAY NIGHT WITH LOWS NEAR OR
SLIGHTLY ABOVE SEASONAL AVERAGES.

.LONG TERM...TUESDAY THROUGH SUNDAY
ISSUED AT 300 PM MDT SUN AUG 30 2015

LONG WAVE TROUGH OVER WESTERN NOAM WILL REMAIN THROUGH
MID WEEK...WITH EVENTUAL BREAKDOWN PER AN ADVECTING STRONG NORTHERN
PAC IMPULSE. THIS WILL SUPPORT VERY WARM TEMPS THROUGH THURS. STRONG
SUPPORT AMONG DETERMINISTIC AND ENSEMBLE MODEL RUNS FOR A STRONG
COLD FRONT TO ADVECT TROUGH THE REGION NEXT WEEKEND AS THE PAC NW
UPPER TROUGH MERGES WITH A STRONG CENTRAL CANADIAN TROUGH.
HOWEVER...PRECIP CHANCES STILL LOOK LOW GIVEN LACK OF SUFFICIENT
MOISTURE WITH THE BULK OF LSA SHIFTING NORTH OF THE AREA. MUCH
COOLER TEMPS LOOK MORE LIKELY BY SUN-MON NEXT WEEK WITH HIGHS IN THE
50S-60S POSSIBLE BY THEN. MEANWHILE...DRY WEATHER IS EXPECTED TUE-
THUR...ALTHOUGH A WEAK SIGNAL REMAINS OVER SCENTRAL SD TUES WHERE A
LL TROUGH AND MOISTURE ADV ARE PROGGED. DID BUMPS TEMPS UP TUE-THUR
GIVEN WARM-DRY SW FLOW WITH WARMER TEMPS NOW PROGGED IN CONSENSUS
BLENDS. OTHERWISE...COOLER CONDS WILL ARRIVE FRI-SAT...HOW COOL WILL
DEPEND ON THE PROGRESSIVE NATURE OF THE UPPER TROUGH...WHICH IS A
LITTLE SLOWER IN THE ECMWF. MUCH COOLER CONDS EXPECTED BY EARLY NEXT
WEEK...ALONG WITH ISOLD-SCT SHRA.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1140 PM MDT SUN AUG 30 2015

A COOL FRONT WILL SLOWLY SLIDE SOUTHEAST THROUGH THE CWA INTO
MONDAY MORNING. GUSTY SOUTHERLY WINDS ARE EXPECTED AHEAD OF IT
WITH GUSTY NORTHWEST WINDS BEHIND IT. LEFTOVER -TSRA WILL END BY
12Z. VFR CIGS/VSBYS ARE EXPECTED THROUGH THE PERIOD.

&&

.FIRE WEATHER...
ISSUED AT 300 PM MDT SUN AUG 30 2015

WARM AND DRY CONDITIONS WILL PERSIST ACROSS NE WY THIS
AFTERNOON...WITH RELATIVE HUMIDITY AROUND 15 PERCENT AND GUSTY
WESTERLY WINDS OF 20 TO 30 MPH. A FEW ISOLD TS ARE ALSO POSSIBLE
WITH DRY LIGHTNING AND GUSTY WINDS LIKELY WITH ANY TS. A COLD
FRONT WILL CROSS THE AREA TONIGHT WITH WINDS SHIFTING NW AND
REMAINING GUSTY FOR A FEW HOURS.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
WY...NONE.
&&

$$

UPDATE...HELGESON
SHORT TERM...26
LONG TERM...JC
AVIATION...HELGESON
FIRE WEATHER...JC




000
FXUS63 KUNR 310541
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
1141 PM MDT SUN AUG 30 2015

.UPDATE...
ISSUED AT 802 PM MDT SUN AUG 30 2015

01Z SURFACE ANALYSIS HAD FRONTAL BOUNDARY FROM CENTRAL ND INTO
CENTRAL WY WITH PREFRONTAL TROUGH FROM CENTRAL ND INTO WESTERN NE.
DEEP DAYTIME MIXING ALONG WITH INCREASE IN MID-LEVEL MOISTURE PER
WATER VAPOUR RESULTED IN MAINLY HIGH-BASED -SHRA/-TSRA ALONG THE
FRONTAL BOUNDARY THIS EVENING...WHICH ARE NOW MOVING NORTHEAST
UNDER MEAN FLOW ALOFT. ACTIVITY WILL SLOWLY WANE OVERNIGHT. UPDATE
TO ADDRESS LATEST TRENDS IN TIMING.

&&

.SHORT TERM...THIS EVENING THROUGH MONDAY NIGHT
ISSUED AT 300 PM MDT SUN AUG 30 2015

CURRENT SURFACE ANALYSIS SHOWS SLOW MOVING COLD FRONT FROM FAR
EASTERN MT THROUGH NORTHEAST INTO CENTRAL WY. UPPER LEVEL ANALYSIS
SHOWS POSITIVELY TILTED RIDGE FROM THE SOUTHERN ROCKIES INTO
EASTERN PORTIONS OF THE NORTHERN PLAINS. SOUTHWEST FLOW ALOFT
BEHIND THE RIDGE FROM THE GREAT BASIN TO THE NORTHERN HIGH PLAINS.
SKIES ARE MOSTLY SUNNY ACROSS EASTERN PORTIONS OF THE CWA...PARTLY
CLOUDY OVER NORTHEAST WY. REGIONAL RADARS SHOW BULK OF SHOWER AND
THUNDERSTORM ACTIVITY OVER NORTHEAST MT INTO NORTHWEST ND NEAR THE
FRONT...AS WELL AS OVER THE HIGHER TERRAIN OF CENTRAL WY. A FEW
SHOWERS AND STORMS ARE NOW DEVELOPING NEAR AND AHEAD OF THE FRONT
OVER NORTHEAST WY. TEMPS ARE IN THE 90S OVER MUCH OF THE
AREA...WITH SOME 80S OVER THE BLACK HILLS. WINDS ARE FROM THE
SOUTH TO SOUTHWEST... BREEZY OVER SOUTH CENTRAL SD AS WELL AS
PORTIONS OF NORTHEAST WY.

COLD FRONT WILL EVER SO SLOWLY CROSS THE FORECAST AREA LATE TODAY
AND TONIGHT...WEAKENING SOME AS IT REACHES SOUTH CENTRAL SD MONDAY
MORNING. MOSTLY ISOLATED SHOWERS AND THUNDERSTORMS CAN BE EXPECTED
WITH THE FRONTAL PASSAGE TONIGHT. THE BEST CHANCES WILL LIKELY BE
OVER FAR NORTHWEST SD THIS EVENING. THE THREAT FOR ANY STRONGER
STORMS WILL BE MINIMAL THROUGH THE EVENING AS CAPE VALUES REMAIN
RELATIVELY LOW ACROSS THE AREA...BUT SOME GUSTY WINDS ARE POSSIBLE.
WINDS WILL SWITCH TO THE WEST AND NORTHWEST BEHIND THE
FRONT...BECOMING BREEZY LATER TONIGHT AND EARLY MONDAY OVER MUCH OF
THE PLAINS. AHEAD OF THE FRONT...WINDS WILL REMAIN BREEZY FROM THE
SOUTH OVER SOUTH CENTRAL SD. LOWS WILL RANGE FROM THE 50S OVER
NORTHEAST WY AND THE BLACK HILLS TO AROUND 70 OVER SOUTH CENTRAL SD.

FRONT WILL SLOWLY SAG SOUTH AND EAST OF THE AREA ON MONDAY AND
FURTHER WEAKEN. WOULD NOT BE SURPRISED TO SEE A SHOWER OR
THUNDERSTORM OVER FAR SOUTHERN SD ON MONDAY IN CLOSER VICINITY TO
THE FRONT...ESPECIALLY SOUTH CENTRAL SD...BUT CHANCES LOOK BELOW 15
PERCENT SO WILL LEAVE FORECAST DRY. SOME COOLER AIR WILL BUILD INTO
THE AREA...WITH HIGHS IN THE 80S ACROSS THE PLAINS...70S IN THE
BLACK HILLS. BRISK NORTHWEST WINDS CAN BE EXPECTED ACROSS THE SD
PLAINS DURING THE DAY. MOSTLY CLEAR MONDAY NIGHT WITH LOWS NEAR OR
SLIGHTLY ABOVE SEASONAL AVERAGES.

.LONG TERM...TUESDAY THROUGH SUNDAY
ISSUED AT 300 PM MDT SUN AUG 30 2015

LONG WAVE TROUGH OVER WESTERN NOAM WILL REMAIN THROUGH
MID WEEK...WITH EVENTUAL BREAKDOWN PER AN ADVECTING STRONG NORTHERN
PAC IMPULSE. THIS WILL SUPPORT VERY WARM TEMPS THROUGH THURS. STRONG
SUPPORT AMONG DETERMINISTIC AND ENSEMBLE MODEL RUNS FOR A STRONG
COLD FRONT TO ADVECT TROUGH THE REGION NEXT WEEKEND AS THE PAC NW
UPPER TROUGH MERGES WITH A STRONG CENTRAL CANADIAN TROUGH.
HOWEVER...PRECIP CHANCES STILL LOOK LOW GIVEN LACK OF SUFFICIENT
MOISTURE WITH THE BULK OF LSA SHIFTING NORTH OF THE AREA. MUCH
COOLER TEMPS LOOK MORE LIKELY BY SUN-MON NEXT WEEK WITH HIGHS IN THE
50S-60S POSSIBLE BY THEN. MEANWHILE...DRY WEATHER IS EXPECTED TUE-
THUR...ALTHOUGH A WEAK SIGNAL REMAINS OVER SCENTRAL SD TUES WHERE A
LL TROUGH AND MOISTURE ADV ARE PROGGED. DID BUMPS TEMPS UP TUE-THUR
GIVEN WARM-DRY SW FLOW WITH WARMER TEMPS NOW PROGGED IN CONSENSUS
BLENDS. OTHERWISE...COOLER CONDS WILL ARRIVE FRI-SAT...HOW COOL WILL
DEPEND ON THE PROGRESSIVE NATURE OF THE UPPER TROUGH...WHICH IS A
LITTLE SLOWER IN THE ECMWF. MUCH COOLER CONDS EXPECTED BY EARLY NEXT
WEEK...ALONG WITH ISOLD-SCT SHRA.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1140 PM MDT SUN AUG 30 2015

A COOL FRONT WILL SLOWLY SLIDE SOUTHEAST THROUGH THE CWA INTO
MONDAY MORNING. GUSTY SOUTHERLY WINDS ARE EXPECTED AHEAD OF IT
WITH GUSTY NORTHWEST WINDS BEHIND IT. LEFTOVER -TSRA WILL END BY
12Z. VFR CIGS/VSBYS ARE EXPECTED THROUGH THE PERIOD.

&&

.FIRE WEATHER...
ISSUED AT 300 PM MDT SUN AUG 30 2015

WARM AND DRY CONDITIONS WILL PERSIST ACROSS NE WY THIS
AFTERNOON...WITH RELATIVE HUMIDITY AROUND 15 PERCENT AND GUSTY
WESTERLY WINDS OF 20 TO 30 MPH. A FEW ISOLD TS ARE ALSO POSSIBLE
WITH DRY LIGHTNING AND GUSTY WINDS LIKELY WITH ANY TS. A COLD
FRONT WILL CROSS THE AREA TONIGHT WITH WINDS SHIFTING NW AND
REMAINING GUSTY FOR A FEW HOURS.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
WY...NONE.
&&

$$

UPDATE...HELGESON
SHORT TERM...26
LONG TERM...JC
AVIATION...HELGESON
FIRE WEATHER...JC




000
FXUS65 KCYS 310519
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
1119 PM MDT SUN AUG 30 2015

.UPDATE...
ISSUED AT 455 PM MDT SUN AUG 30 2015

MAY A FEW MINOR ADJUSTMENTS TO THE FORECAST SPREADING CHANCES OF
SHOWERS AND THUNDERSTORMS SLIGHTLY FARTHER EAST INTO THIS EVENING.
ALSO REMOVED THE MENTION OF THUNDERSTORMS AFTER MIDNIGHT.

&&

.SHORT TERM...(THIS EVENING THROUGH TUESDAY NIGHT)

ISSUED AT 300 PM MDT SUN AUG 30 2015

SCATTERED LIGHT SHOWERS AND ISOLATED THUNDERSTORMS WILL
MOVE ACROSS SOUTHEAST WYOMING THIS AFTERNOON AND EVENING. SOME OF
THIS ACTIVITY MAY REACH THE NEBRASKA PANHANDLE. 40 TO 50 SPREADS
BETWEEN TEMPERATURES AND DEWPOINTS WILL MAKE IT TOUGH FOR MOISTURE
TO REACH THE GROUND SUCH THAT MEASURABLE RAIN WILL BE MINIMAL
WHERE IT DOES REACH THE SURFACE. THE LARGE SPREADS BETWEEN
TEMPERATURE AND DEW POINTS WILL PRODUCE THE POTENTIAL FOR
RELATIVELY STRONG DOWN DRAFTS CAPABLE OF PRODUCING WIND GUSTS OF
50 TO 60 MPH...IF NOT GREATER. COW CREEK RAWS ALREADY MEASURED A
GUST OF 54 MPH AT 243 PM. COOLING ALOFT...THE REAR ENTRANCE OF AN
UPPER LEVEL JET...AND MOIST MID FLOW MAY KEEP SOME SHOWER
ACTIVITY LINGERING INTO THE OVERNIGHT HOURS BUT STRONG WIND GUST
POTENTIAL WILL SUBSIDE.

MONDAY WILL SEE A BREAK IN THE VERY WARM TEMPERATURES WITH HIGHS
TYPICALLY IN THE 80S ACROSS THE FORECAST AREA. MID LEVEL MOISTURE
IS PROGGED TO BE IN PLACE ACROSS SOUTHERN PORTIONS OF THE FORECAST
AREA WHICH SHOULD YIELD A FEW MORE AFTERNOON AND EVENING SHOWERS
AND THUNDERSTORMS. AGAIN SEVERE THUNDERSTORMS ARE NOT A CONCERN
BUT A FEW STRONGER WIND GUSTS MAY BE POSSIBLE.

WARMER TEMPERATURES RETURN TUESDAY AS THE RIDGE REBOUNDS ACROSS
THE NORTHERN ROCKIES. HIGH TEMPERATURES TO WARM INTO THE 90S
ACROSS THE PLAINS AND 80S FARTHER WEST. LESSER CHANCES FOR
PRECIPITATION TUESDAY BUT MAY SEE A COUPLE SHOWERS DEVELOP OFF THE
HIGHER TERRAIN.

.LONG TERM...(WEDNESDAY THROUGH SUNDAY)
ISSUED AT 300 PM MDT SUN AUG 30 2015

THERE WILL CONTINUE TO BE SOUTHWESTERLY FLOW ALOFT THROUGHOUT THE
MAJORITY OF THE WEEK. A DRY AIRMASS ALOFT ON WEDNESDAY COULD
BRING CONCERNS FOR FIRE WEATHER WITH RH VALUES DOWN INTO THE MID
TO LOWER TEENS FOR CONVERSE AND NIOBRARA COUNTIES. TEMPERATURES
WILL REMAIN WARM OVER THE COURSE OF THE WEEK WITH POPS BEING LOW.
A FEW ISOLATED THUNDERSTORMS MAY BE SEEN OVER THE SIERRA MADRES
AND SNOWY RANGES ON WEDNESDAY. THURSDAY AND FRIDAY ARE EXPECTED TO
CONTINUE THIS HOT/DRY TREND. THIS PATTERN WILL CHANGE OVER THE
WEEKEND WHEN A UPPER LEVEL TROUGH IS PROJECTED TO MOVE EASTWARD
FROM THE PACIFIC NORTHWEST. A WEAK COLD FRONT PASSAGE ON SATURDAY
WILL BRING SOME SCATTERED SHOWERS AND THUNDERSTORMS...MAINLY
AFFECTING EAST OF THE LARAMIE RANGE INTO THE NEBRASKA PANHANDLE.
THE PASSAGE OF AN UPPER LEVEL TROUGH ON SUNDAY WILL BRING
TEMPERATURES AS WELL AS A CONTINUED CHANCE OF THUNDERSTORMS FOR
THE NEBRASKA PANHANDLE.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1119 PM MDT SUN AUG 30 2015

VFR EXPECTED OVER ALL TERMINALS THROUGH THE PERIOD WITH MID LEVEL
CLOUDS SPREADING ACROSS THE AREA. ISOLATED SHOWERS POSSIBLE OVERNIGHT
AND AGAIN MONDAY AFTERNOON.

&&

.FIRE WEATHER...
ISSUED AT 157 PM MDT SUN AUG 30 2015

MAINLY DRY AND WARM THROUGH THIS WEEK ALTHOUGH THERE WILL
BE SOME CHANCES FOR WETTING RAINS. A FRONTAL BOUNDARY WILL
BRING SCATTERED SHOWERS AND A FEW THUNDERSTORMS TO THE AREA
INTO THIS EVENING. WIND GUSTS TO AROUND 55 MPH WILL OCCUR
WITH SOME SHOWERS AND THUNDERSTORMS INTO THIS EVENING.

COOLER TEMPERATURES MONDAY WILL SUPPRESS CRITICAL FIRE
WEATHER POTENTIAL BUT LATER INTO THE WEEK TEMPERATURES WILL
BE UNSEASONABLY WARM WITH HUMIDITIES DROPPING INTO THE 10
TO 15 PERCENT RANGE ACROSS SOUTHEAST WYOMING. WINDS WILL
BE GUSTY SEVERAL AFTERNOONS DURING THE WEEK SUCH THAT
CRITICAL FIRE THRESHOLDS MAY BE REACHED.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.

NE...NONE.

&&

$$

UPDATE...SML
SHORT TERM...SML
LONG TERM...GCC
AVIATION...RE
FIRE WEATHER...SML



000
FXUS65 KCYS 310519
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
1119 PM MDT SUN AUG 30 2015

.UPDATE...
ISSUED AT 455 PM MDT SUN AUG 30 2015

MAY A FEW MINOR ADJUSTMENTS TO THE FORECAST SPREADING CHANCES OF
SHOWERS AND THUNDERSTORMS SLIGHTLY FARTHER EAST INTO THIS EVENING.
ALSO REMOVED THE MENTION OF THUNDERSTORMS AFTER MIDNIGHT.

&&

.SHORT TERM...(THIS EVENING THROUGH TUESDAY NIGHT)

ISSUED AT 300 PM MDT SUN AUG 30 2015

SCATTERED LIGHT SHOWERS AND ISOLATED THUNDERSTORMS WILL
MOVE ACROSS SOUTHEAST WYOMING THIS AFTERNOON AND EVENING. SOME OF
THIS ACTIVITY MAY REACH THE NEBRASKA PANHANDLE. 40 TO 50 SPREADS
BETWEEN TEMPERATURES AND DEWPOINTS WILL MAKE IT TOUGH FOR MOISTURE
TO REACH THE GROUND SUCH THAT MEASURABLE RAIN WILL BE MINIMAL
WHERE IT DOES REACH THE SURFACE. THE LARGE SPREADS BETWEEN
TEMPERATURE AND DEW POINTS WILL PRODUCE THE POTENTIAL FOR
RELATIVELY STRONG DOWN DRAFTS CAPABLE OF PRODUCING WIND GUSTS OF
50 TO 60 MPH...IF NOT GREATER. COW CREEK RAWS ALREADY MEASURED A
GUST OF 54 MPH AT 243 PM. COOLING ALOFT...THE REAR ENTRANCE OF AN
UPPER LEVEL JET...AND MOIST MID FLOW MAY KEEP SOME SHOWER
ACTIVITY LINGERING INTO THE OVERNIGHT HOURS BUT STRONG WIND GUST
POTENTIAL WILL SUBSIDE.

MONDAY WILL SEE A BREAK IN THE VERY WARM TEMPERATURES WITH HIGHS
TYPICALLY IN THE 80S ACROSS THE FORECAST AREA. MID LEVEL MOISTURE
IS PROGGED TO BE IN PLACE ACROSS SOUTHERN PORTIONS OF THE FORECAST
AREA WHICH SHOULD YIELD A FEW MORE AFTERNOON AND EVENING SHOWERS
AND THUNDERSTORMS. AGAIN SEVERE THUNDERSTORMS ARE NOT A CONCERN
BUT A FEW STRONGER WIND GUSTS MAY BE POSSIBLE.

WARMER TEMPERATURES RETURN TUESDAY AS THE RIDGE REBOUNDS ACROSS
THE NORTHERN ROCKIES. HIGH TEMPERATURES TO WARM INTO THE 90S
ACROSS THE PLAINS AND 80S FARTHER WEST. LESSER CHANCES FOR
PRECIPITATION TUESDAY BUT MAY SEE A COUPLE SHOWERS DEVELOP OFF THE
HIGHER TERRAIN.

.LONG TERM...(WEDNESDAY THROUGH SUNDAY)
ISSUED AT 300 PM MDT SUN AUG 30 2015

THERE WILL CONTINUE TO BE SOUTHWESTERLY FLOW ALOFT THROUGHOUT THE
MAJORITY OF THE WEEK. A DRY AIRMASS ALOFT ON WEDNESDAY COULD
BRING CONCERNS FOR FIRE WEATHER WITH RH VALUES DOWN INTO THE MID
TO LOWER TEENS FOR CONVERSE AND NIOBRARA COUNTIES. TEMPERATURES
WILL REMAIN WARM OVER THE COURSE OF THE WEEK WITH POPS BEING LOW.
A FEW ISOLATED THUNDERSTORMS MAY BE SEEN OVER THE SIERRA MADRES
AND SNOWY RANGES ON WEDNESDAY. THURSDAY AND FRIDAY ARE EXPECTED TO
CONTINUE THIS HOT/DRY TREND. THIS PATTERN WILL CHANGE OVER THE
WEEKEND WHEN A UPPER LEVEL TROUGH IS PROJECTED TO MOVE EASTWARD
FROM THE PACIFIC NORTHWEST. A WEAK COLD FRONT PASSAGE ON SATURDAY
WILL BRING SOME SCATTERED SHOWERS AND THUNDERSTORMS...MAINLY
AFFECTING EAST OF THE LARAMIE RANGE INTO THE NEBRASKA PANHANDLE.
THE PASSAGE OF AN UPPER LEVEL TROUGH ON SUNDAY WILL BRING
TEMPERATURES AS WELL AS A CONTINUED CHANCE OF THUNDERSTORMS FOR
THE NEBRASKA PANHANDLE.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1119 PM MDT SUN AUG 30 2015

VFR EXPECTED OVER ALL TERMINALS THROUGH THE PERIOD WITH MID LEVEL
CLOUDS SPREADING ACROSS THE AREA. ISOLATED SHOWERS POSSIBLE OVERNIGHT
AND AGAIN MONDAY AFTERNOON.

&&

.FIRE WEATHER...
ISSUED AT 157 PM MDT SUN AUG 30 2015

MAINLY DRY AND WARM THROUGH THIS WEEK ALTHOUGH THERE WILL
BE SOME CHANCES FOR WETTING RAINS. A FRONTAL BOUNDARY WILL
BRING SCATTERED SHOWERS AND A FEW THUNDERSTORMS TO THE AREA
INTO THIS EVENING. WIND GUSTS TO AROUND 55 MPH WILL OCCUR
WITH SOME SHOWERS AND THUNDERSTORMS INTO THIS EVENING.

COOLER TEMPERATURES MONDAY WILL SUPPRESS CRITICAL FIRE
WEATHER POTENTIAL BUT LATER INTO THE WEEK TEMPERATURES WILL
BE UNSEASONABLY WARM WITH HUMIDITIES DROPPING INTO THE 10
TO 15 PERCENT RANGE ACROSS SOUTHEAST WYOMING. WINDS WILL
BE GUSTY SEVERAL AFTERNOONS DURING THE WEEK SUCH THAT
CRITICAL FIRE THRESHOLDS MAY BE REACHED.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.

NE...NONE.

&&

$$

UPDATE...SML
SHORT TERM...SML
LONG TERM...GCC
AVIATION...RE
FIRE WEATHER...SML



000
FXUS65 KCYS 310519
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
1119 PM MDT SUN AUG 30 2015

.UPDATE...
ISSUED AT 455 PM MDT SUN AUG 30 2015

MAY A FEW MINOR ADJUSTMENTS TO THE FORECAST SPREADING CHANCES OF
SHOWERS AND THUNDERSTORMS SLIGHTLY FARTHER EAST INTO THIS EVENING.
ALSO REMOVED THE MENTION OF THUNDERSTORMS AFTER MIDNIGHT.

&&

.SHORT TERM...(THIS EVENING THROUGH TUESDAY NIGHT)

ISSUED AT 300 PM MDT SUN AUG 30 2015

SCATTERED LIGHT SHOWERS AND ISOLATED THUNDERSTORMS WILL
MOVE ACROSS SOUTHEAST WYOMING THIS AFTERNOON AND EVENING. SOME OF
THIS ACTIVITY MAY REACH THE NEBRASKA PANHANDLE. 40 TO 50 SPREADS
BETWEEN TEMPERATURES AND DEWPOINTS WILL MAKE IT TOUGH FOR MOISTURE
TO REACH THE GROUND SUCH THAT MEASURABLE RAIN WILL BE MINIMAL
WHERE IT DOES REACH THE SURFACE. THE LARGE SPREADS BETWEEN
TEMPERATURE AND DEW POINTS WILL PRODUCE THE POTENTIAL FOR
RELATIVELY STRONG DOWN DRAFTS CAPABLE OF PRODUCING WIND GUSTS OF
50 TO 60 MPH...IF NOT GREATER. COW CREEK RAWS ALREADY MEASURED A
GUST OF 54 MPH AT 243 PM. COOLING ALOFT...THE REAR ENTRANCE OF AN
UPPER LEVEL JET...AND MOIST MID FLOW MAY KEEP SOME SHOWER
ACTIVITY LINGERING INTO THE OVERNIGHT HOURS BUT STRONG WIND GUST
POTENTIAL WILL SUBSIDE.

MONDAY WILL SEE A BREAK IN THE VERY WARM TEMPERATURES WITH HIGHS
TYPICALLY IN THE 80S ACROSS THE FORECAST AREA. MID LEVEL MOISTURE
IS PROGGED TO BE IN PLACE ACROSS SOUTHERN PORTIONS OF THE FORECAST
AREA WHICH SHOULD YIELD A FEW MORE AFTERNOON AND EVENING SHOWERS
AND THUNDERSTORMS. AGAIN SEVERE THUNDERSTORMS ARE NOT A CONCERN
BUT A FEW STRONGER WIND GUSTS MAY BE POSSIBLE.

WARMER TEMPERATURES RETURN TUESDAY AS THE RIDGE REBOUNDS ACROSS
THE NORTHERN ROCKIES. HIGH TEMPERATURES TO WARM INTO THE 90S
ACROSS THE PLAINS AND 80S FARTHER WEST. LESSER CHANCES FOR
PRECIPITATION TUESDAY BUT MAY SEE A COUPLE SHOWERS DEVELOP OFF THE
HIGHER TERRAIN.

.LONG TERM...(WEDNESDAY THROUGH SUNDAY)
ISSUED AT 300 PM MDT SUN AUG 30 2015

THERE WILL CONTINUE TO BE SOUTHWESTERLY FLOW ALOFT THROUGHOUT THE
MAJORITY OF THE WEEK. A DRY AIRMASS ALOFT ON WEDNESDAY COULD
BRING CONCERNS FOR FIRE WEATHER WITH RH VALUES DOWN INTO THE MID
TO LOWER TEENS FOR CONVERSE AND NIOBRARA COUNTIES. TEMPERATURES
WILL REMAIN WARM OVER THE COURSE OF THE WEEK WITH POPS BEING LOW.
A FEW ISOLATED THUNDERSTORMS MAY BE SEEN OVER THE SIERRA MADRES
AND SNOWY RANGES ON WEDNESDAY. THURSDAY AND FRIDAY ARE EXPECTED TO
CONTINUE THIS HOT/DRY TREND. THIS PATTERN WILL CHANGE OVER THE
WEEKEND WHEN A UPPER LEVEL TROUGH IS PROJECTED TO MOVE EASTWARD
FROM THE PACIFIC NORTHWEST. A WEAK COLD FRONT PASSAGE ON SATURDAY
WILL BRING SOME SCATTERED SHOWERS AND THUNDERSTORMS...MAINLY
AFFECTING EAST OF THE LARAMIE RANGE INTO THE NEBRASKA PANHANDLE.
THE PASSAGE OF AN UPPER LEVEL TROUGH ON SUNDAY WILL BRING
TEMPERATURES AS WELL AS A CONTINUED CHANCE OF THUNDERSTORMS FOR
THE NEBRASKA PANHANDLE.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1119 PM MDT SUN AUG 30 2015

VFR EXPECTED OVER ALL TERMINALS THROUGH THE PERIOD WITH MID LEVEL
CLOUDS SPREADING ACROSS THE AREA. ISOLATED SHOWERS POSSIBLE OVERNIGHT
AND AGAIN MONDAY AFTERNOON.

&&

.FIRE WEATHER...
ISSUED AT 157 PM MDT SUN AUG 30 2015

MAINLY DRY AND WARM THROUGH THIS WEEK ALTHOUGH THERE WILL
BE SOME CHANCES FOR WETTING RAINS. A FRONTAL BOUNDARY WILL
BRING SCATTERED SHOWERS AND A FEW THUNDERSTORMS TO THE AREA
INTO THIS EVENING. WIND GUSTS TO AROUND 55 MPH WILL OCCUR
WITH SOME SHOWERS AND THUNDERSTORMS INTO THIS EVENING.

COOLER TEMPERATURES MONDAY WILL SUPPRESS CRITICAL FIRE
WEATHER POTENTIAL BUT LATER INTO THE WEEK TEMPERATURES WILL
BE UNSEASONABLY WARM WITH HUMIDITIES DROPPING INTO THE 10
TO 15 PERCENT RANGE ACROSS SOUTHEAST WYOMING. WINDS WILL
BE GUSTY SEVERAL AFTERNOONS DURING THE WEEK SUCH THAT
CRITICAL FIRE THRESHOLDS MAY BE REACHED.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.

NE...NONE.

&&

$$

UPDATE...SML
SHORT TERM...SML
LONG TERM...GCC
AVIATION...RE
FIRE WEATHER...SML



000
FXUS65 KCYS 310519
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
1119 PM MDT SUN AUG 30 2015

.UPDATE...
ISSUED AT 455 PM MDT SUN AUG 30 2015

MAY A FEW MINOR ADJUSTMENTS TO THE FORECAST SPREADING CHANCES OF
SHOWERS AND THUNDERSTORMS SLIGHTLY FARTHER EAST INTO THIS EVENING.
ALSO REMOVED THE MENTION OF THUNDERSTORMS AFTER MIDNIGHT.

&&

.SHORT TERM...(THIS EVENING THROUGH TUESDAY NIGHT)

ISSUED AT 300 PM MDT SUN AUG 30 2015

SCATTERED LIGHT SHOWERS AND ISOLATED THUNDERSTORMS WILL
MOVE ACROSS SOUTHEAST WYOMING THIS AFTERNOON AND EVENING. SOME OF
THIS ACTIVITY MAY REACH THE NEBRASKA PANHANDLE. 40 TO 50 SPREADS
BETWEEN TEMPERATURES AND DEWPOINTS WILL MAKE IT TOUGH FOR MOISTURE
TO REACH THE GROUND SUCH THAT MEASURABLE RAIN WILL BE MINIMAL
WHERE IT DOES REACH THE SURFACE. THE LARGE SPREADS BETWEEN
TEMPERATURE AND DEW POINTS WILL PRODUCE THE POTENTIAL FOR
RELATIVELY STRONG DOWN DRAFTS CAPABLE OF PRODUCING WIND GUSTS OF
50 TO 60 MPH...IF NOT GREATER. COW CREEK RAWS ALREADY MEASURED A
GUST OF 54 MPH AT 243 PM. COOLING ALOFT...THE REAR ENTRANCE OF AN
UPPER LEVEL JET...AND MOIST MID FLOW MAY KEEP SOME SHOWER
ACTIVITY LINGERING INTO THE OVERNIGHT HOURS BUT STRONG WIND GUST
POTENTIAL WILL SUBSIDE.

MONDAY WILL SEE A BREAK IN THE VERY WARM TEMPERATURES WITH HIGHS
TYPICALLY IN THE 80S ACROSS THE FORECAST AREA. MID LEVEL MOISTURE
IS PROGGED TO BE IN PLACE ACROSS SOUTHERN PORTIONS OF THE FORECAST
AREA WHICH SHOULD YIELD A FEW MORE AFTERNOON AND EVENING SHOWERS
AND THUNDERSTORMS. AGAIN SEVERE THUNDERSTORMS ARE NOT A CONCERN
BUT A FEW STRONGER WIND GUSTS MAY BE POSSIBLE.

WARMER TEMPERATURES RETURN TUESDAY AS THE RIDGE REBOUNDS ACROSS
THE NORTHERN ROCKIES. HIGH TEMPERATURES TO WARM INTO THE 90S
ACROSS THE PLAINS AND 80S FARTHER WEST. LESSER CHANCES FOR
PRECIPITATION TUESDAY BUT MAY SEE A COUPLE SHOWERS DEVELOP OFF THE
HIGHER TERRAIN.

.LONG TERM...(WEDNESDAY THROUGH SUNDAY)
ISSUED AT 300 PM MDT SUN AUG 30 2015

THERE WILL CONTINUE TO BE SOUTHWESTERLY FLOW ALOFT THROUGHOUT THE
MAJORITY OF THE WEEK. A DRY AIRMASS ALOFT ON WEDNESDAY COULD
BRING CONCERNS FOR FIRE WEATHER WITH RH VALUES DOWN INTO THE MID
TO LOWER TEENS FOR CONVERSE AND NIOBRARA COUNTIES. TEMPERATURES
WILL REMAIN WARM OVER THE COURSE OF THE WEEK WITH POPS BEING LOW.
A FEW ISOLATED THUNDERSTORMS MAY BE SEEN OVER THE SIERRA MADRES
AND SNOWY RANGES ON WEDNESDAY. THURSDAY AND FRIDAY ARE EXPECTED TO
CONTINUE THIS HOT/DRY TREND. THIS PATTERN WILL CHANGE OVER THE
WEEKEND WHEN A UPPER LEVEL TROUGH IS PROJECTED TO MOVE EASTWARD
FROM THE PACIFIC NORTHWEST. A WEAK COLD FRONT PASSAGE ON SATURDAY
WILL BRING SOME SCATTERED SHOWERS AND THUNDERSTORMS...MAINLY
AFFECTING EAST OF THE LARAMIE RANGE INTO THE NEBRASKA PANHANDLE.
THE PASSAGE OF AN UPPER LEVEL TROUGH ON SUNDAY WILL BRING
TEMPERATURES AS WELL AS A CONTINUED CHANCE OF THUNDERSTORMS FOR
THE NEBRASKA PANHANDLE.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1119 PM MDT SUN AUG 30 2015

VFR EXPECTED OVER ALL TERMINALS THROUGH THE PERIOD WITH MID LEVEL
CLOUDS SPREADING ACROSS THE AREA. ISOLATED SHOWERS POSSIBLE OVERNIGHT
AND AGAIN MONDAY AFTERNOON.

&&

.FIRE WEATHER...
ISSUED AT 157 PM MDT SUN AUG 30 2015

MAINLY DRY AND WARM THROUGH THIS WEEK ALTHOUGH THERE WILL
BE SOME CHANCES FOR WETTING RAINS. A FRONTAL BOUNDARY WILL
BRING SCATTERED SHOWERS AND A FEW THUNDERSTORMS TO THE AREA
INTO THIS EVENING. WIND GUSTS TO AROUND 55 MPH WILL OCCUR
WITH SOME SHOWERS AND THUNDERSTORMS INTO THIS EVENING.

COOLER TEMPERATURES MONDAY WILL SUPPRESS CRITICAL FIRE
WEATHER POTENTIAL BUT LATER INTO THE WEEK TEMPERATURES WILL
BE UNSEASONABLY WARM WITH HUMIDITIES DROPPING INTO THE 10
TO 15 PERCENT RANGE ACROSS SOUTHEAST WYOMING. WINDS WILL
BE GUSTY SEVERAL AFTERNOONS DURING THE WEEK SUCH THAT
CRITICAL FIRE THRESHOLDS MAY BE REACHED.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.

NE...NONE.

&&

$$

UPDATE...SML
SHORT TERM...SML
LONG TERM...GCC
AVIATION...RE
FIRE WEATHER...SML



000
FXUS65 KCYS 310519
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
1119 PM MDT SUN AUG 30 2015

.UPDATE...
ISSUED AT 455 PM MDT SUN AUG 30 2015

MAY A FEW MINOR ADJUSTMENTS TO THE FORECAST SPREADING CHANCES OF
SHOWERS AND THUNDERSTORMS SLIGHTLY FARTHER EAST INTO THIS EVENING.
ALSO REMOVED THE MENTION OF THUNDERSTORMS AFTER MIDNIGHT.

&&

.SHORT TERM...(THIS EVENING THROUGH TUESDAY NIGHT)

ISSUED AT 300 PM MDT SUN AUG 30 2015

SCATTERED LIGHT SHOWERS AND ISOLATED THUNDERSTORMS WILL
MOVE ACROSS SOUTHEAST WYOMING THIS AFTERNOON AND EVENING. SOME OF
THIS ACTIVITY MAY REACH THE NEBRASKA PANHANDLE. 40 TO 50 SPREADS
BETWEEN TEMPERATURES AND DEWPOINTS WILL MAKE IT TOUGH FOR MOISTURE
TO REACH THE GROUND SUCH THAT MEASURABLE RAIN WILL BE MINIMAL
WHERE IT DOES REACH THE SURFACE. THE LARGE SPREADS BETWEEN
TEMPERATURE AND DEW POINTS WILL PRODUCE THE POTENTIAL FOR
RELATIVELY STRONG DOWN DRAFTS CAPABLE OF PRODUCING WIND GUSTS OF
50 TO 60 MPH...IF NOT GREATER. COW CREEK RAWS ALREADY MEASURED A
GUST OF 54 MPH AT 243 PM. COOLING ALOFT...THE REAR ENTRANCE OF AN
UPPER LEVEL JET...AND MOIST MID FLOW MAY KEEP SOME SHOWER
ACTIVITY LINGERING INTO THE OVERNIGHT HOURS BUT STRONG WIND GUST
POTENTIAL WILL SUBSIDE.

MONDAY WILL SEE A BREAK IN THE VERY WARM TEMPERATURES WITH HIGHS
TYPICALLY IN THE 80S ACROSS THE FORECAST AREA. MID LEVEL MOISTURE
IS PROGGED TO BE IN PLACE ACROSS SOUTHERN PORTIONS OF THE FORECAST
AREA WHICH SHOULD YIELD A FEW MORE AFTERNOON AND EVENING SHOWERS
AND THUNDERSTORMS. AGAIN SEVERE THUNDERSTORMS ARE NOT A CONCERN
BUT A FEW STRONGER WIND GUSTS MAY BE POSSIBLE.

WARMER TEMPERATURES RETURN TUESDAY AS THE RIDGE REBOUNDS ACROSS
THE NORTHERN ROCKIES. HIGH TEMPERATURES TO WARM INTO THE 90S
ACROSS THE PLAINS AND 80S FARTHER WEST. LESSER CHANCES FOR
PRECIPITATION TUESDAY BUT MAY SEE A COUPLE SHOWERS DEVELOP OFF THE
HIGHER TERRAIN.

.LONG TERM...(WEDNESDAY THROUGH SUNDAY)
ISSUED AT 300 PM MDT SUN AUG 30 2015

THERE WILL CONTINUE TO BE SOUTHWESTERLY FLOW ALOFT THROUGHOUT THE
MAJORITY OF THE WEEK. A DRY AIRMASS ALOFT ON WEDNESDAY COULD
BRING CONCERNS FOR FIRE WEATHER WITH RH VALUES DOWN INTO THE MID
TO LOWER TEENS FOR CONVERSE AND NIOBRARA COUNTIES. TEMPERATURES
WILL REMAIN WARM OVER THE COURSE OF THE WEEK WITH POPS BEING LOW.
A FEW ISOLATED THUNDERSTORMS MAY BE SEEN OVER THE SIERRA MADRES
AND SNOWY RANGES ON WEDNESDAY. THURSDAY AND FRIDAY ARE EXPECTED TO
CONTINUE THIS HOT/DRY TREND. THIS PATTERN WILL CHANGE OVER THE
WEEKEND WHEN A UPPER LEVEL TROUGH IS PROJECTED TO MOVE EASTWARD
FROM THE PACIFIC NORTHWEST. A WEAK COLD FRONT PASSAGE ON SATURDAY
WILL BRING SOME SCATTERED SHOWERS AND THUNDERSTORMS...MAINLY
AFFECTING EAST OF THE LARAMIE RANGE INTO THE NEBRASKA PANHANDLE.
THE PASSAGE OF AN UPPER LEVEL TROUGH ON SUNDAY WILL BRING
TEMPERATURES AS WELL AS A CONTINUED CHANCE OF THUNDERSTORMS FOR
THE NEBRASKA PANHANDLE.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1119 PM MDT SUN AUG 30 2015

VFR EXPECTED OVER ALL TERMINALS THROUGH THE PERIOD WITH MID LEVEL
CLOUDS SPREADING ACROSS THE AREA. ISOLATED SHOWERS POSSIBLE OVERNIGHT
AND AGAIN MONDAY AFTERNOON.

&&

.FIRE WEATHER...
ISSUED AT 157 PM MDT SUN AUG 30 2015

MAINLY DRY AND WARM THROUGH THIS WEEK ALTHOUGH THERE WILL
BE SOME CHANCES FOR WETTING RAINS. A FRONTAL BOUNDARY WILL
BRING SCATTERED SHOWERS AND A FEW THUNDERSTORMS TO THE AREA
INTO THIS EVENING. WIND GUSTS TO AROUND 55 MPH WILL OCCUR
WITH SOME SHOWERS AND THUNDERSTORMS INTO THIS EVENING.

COOLER TEMPERATURES MONDAY WILL SUPPRESS CRITICAL FIRE
WEATHER POTENTIAL BUT LATER INTO THE WEEK TEMPERATURES WILL
BE UNSEASONABLY WARM WITH HUMIDITIES DROPPING INTO THE 10
TO 15 PERCENT RANGE ACROSS SOUTHEAST WYOMING. WINDS WILL
BE GUSTY SEVERAL AFTERNOONS DURING THE WEEK SUCH THAT
CRITICAL FIRE THRESHOLDS MAY BE REACHED.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.

NE...NONE.

&&

$$

UPDATE...SML
SHORT TERM...SML
LONG TERM...GCC
AVIATION...RE
FIRE WEATHER...SML



000
FXUS65 KRIW 310346
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
946 PM MDT SUN AUG 30 2015

.UPDATE...CANADIAN COLD FRONT WAS JUST NORTH AND WEST OF BILLINGS
AT 3Z...AND STILL ON TRACK TO PLOW ACROSS THE NORTHERN BORDER
AROUND 06Z...UP TO THE OWL CREEK MOUNTAINS 2Z-3Z. DRY AIR HAS
PUNCHED IN ACROSS WESTERN AND CENTRAL WYOMING WITH A FEW STORMS
CONTINUING TO TRACK MAINLY ALONG AND SOUTH OF INTERSTATE 80 AND
AHEAD OF THE FRONT ACROSS THE NORTHERN BIGHORN RANGE AND EASTERN
MONTANA. MAIN CONCERN CONTINUES TO BE RAPID SPREAD OF ANY FIRES
ACROSS NORTH CENTRAL AREAS WITH GUSTY NORTH WIND BEHIND THE
FRONT. RED FLAG WARNINGS REMAIN IN EFFECT FOR THESE AREAS UNTIL 3
AM. ALL OTHER RED FLAG WARNINGS HAVE BEEN ALLOWED TO EXPIRE.

&&

.PREV DISCUSSION... /ISSUED 237 PM MDT SUN AUG 30 2015/

SHORT TERM...TONIGHT THROUGH MONDAY

A TROUGH AND COLD FRONT CONTINUE TO TRACK EASTWARD ACROSS THE
INTERMOUNTAIN WEST. THE COLD FRONT IS LYING NEAR THE MONTANA BORDER
AND IS EXPECTED TO SURGE SOUTHWARD AGAIN AROUND SUNSET WITH THE
MAIN PUSH ARRIVING TOWARD MIDNIGHT...THOUGH THE TIMING ON COLD
FRONTS CAN BE TRICKY AS THEY OFTEN MOVE FASTER THAN EXPECTED. WE
CAN CONTINUE TO EXPECT RED FLAG CONDITIONS SOUTH OF THE FRONT AND
MUCH COOLER AND MOIST CONDITIONS TO THE NORTH THROUGH THE EARLY
EVENING HOURS.

THERE IS ALSO SOME DECENT LIFT ON THE FRONT SIDE OF THIS TROUGH
WITH JET SUPPORT ALOFT...A THETA E RIDGE LYING APPROXIMATELY FROM
FLAMING GORGE TO KAYCEE...AND QG FORCING ARRIVING LATER IN THE
EVENING. AREAS WITH DECENT LOW LEVEL MOISTURE IN PLACE...ACROSS
THE WEST AND THE SOUTH...AND ON THE OTHER SIDE OF THE FRONT WILL
SEE WET THUNDERSTORMS AND AREAS LIKE THE SOUTHERN BIGHORN
BASIN...NATRONA COUNTY AND FREMONT COUNTY WILL SEE MAINLY DRY
THUNDERSTORMS THROUGH SUNSET...SHOWERS AND STORMS HAVE A BETTER
CHANCE OF PRODUCING A WETTING RAIN THEREAFTER.

MONDAY WILL BE DRY AGAIN BUT LESS WINDY AS WE LOSE THE GRADIENT AT
THE SURFACE AND ALOFT. TEMPERATURES WILL BE CLOSER TO SEASONAL
NORMS WITH HIGHS IN THE LOW TO MID 80S EAST...MID TO UPPER 70S
WEST AND SOUTH. A PLUME OF MOISTURE ACROSS COLORADO COULD BEGIN TO
POKE NORTH INTO SOUTHERN SWEETWATER COUNTY WITH A FEW STRAY
AFTERNOON STORMS POSSIBLE OTHERWISE IT WILL BE DRY AND RAIN FREE.

LONG TERM...MONDAY NIGHT THROUGH SUNDAY

MEDIUM-RANGE FORECAST MODELS ARE CONSISTENT AND AGAIN IN FAIRLY GOOD
AGREEMENT THROUGH THE FORECAST PERIOD. WEST-SOUTHWEST FLOW ALOFT ON
TUESDAY WILL BACK TO THE SOUTHWEST WEDNESDAY AND THURSDAY AS A
TROUGH DEEPENS OVER THE PACIFIC NORTHWEST. LIMITED MOISTURE IN
SOUTHWEST FLOW FOR TUESDAY...BUT SOME PRECIPITABLE WATER VALUES
AROUND 0.70 INCHES COULD LEAD TO WEAK CONVECTION IN JOHNSON AND
NATRONA COUNTIES. HOWEVER...WITH DEW POINTS IN THE 30S HAVE
CONTINUED A GENERALLY DRY FORECAST FOR NOW. SOUTHWEST FLOW ADVECTS
IN DRIER AIR FROM THE GREAT BASIN WEDNESDAY AND THURSDAY AND DO NOT
SEE MUCH IN THE WAY OF AVAILABLE MOISTURE FOR ANY CONVECTION.
SURFACE DEW POINTS WILL GENERALLY RANGE FROM 25-35F. ALSO...
WEDNESDAY LOOKS TO BE THE WARMEST DAY OF THE WEEK WITH TEMPERATURES
RUNNING ABOUT 5-10F ABOVE NORMAL AND THE NORTHERN BASINS PUSHING
INTO THE 90S AGAIN. THE COMBINATION OF THE UNSEASONABLY HOT
TEMPERATURES...LOW HUMIDITY...AND INCREASING SOUTHWEST WIND OF 15-30
MPH WILL VERY LIKELY LEAD TO CRITICAL FIRE WEATHER CONDITIONS FOR
WEDNESDAY AND MOST PROBABLY THURSDAY. MOST INTENSE WINDS WILL BE IN
THE CORRIDOR FROM ROCK SPRINGS TO CASPER. THOSE WITH FIRE WEATHER
INTERESTS SHOULD BE AWARE OF THE LIKELIHOOD OF THESE CONDITIONS FOR
WEDNESDAY AND THURSDAY AND BE ON THE ALERT FOR POSSIBLE HIGHLIGHTS ISSUED
EARLY THIS WEEK. FIRST UPPER LOW IN THE PACIFIC NORTHWEST TROUGH
WILL EJECT INTO ALBERTA THURSDAY. THIS UPPER LOW WILL QUICKLY BE
REPLACED BY ANOTHER SHORTWAVE THAT WILL DROP INTO THE BASE OF THE
TROUGH OVER THE INTERMOUNTAIN WEST FOR FRIDAY. UPPER FLOW WILL
PARALLEL SURFACE FRONT THAT WILL BE ORIENTED NORTHEAST-SOUTHWEST
JUST TO THE WEST OF WYOMING FOR FRIDAY. HAVE NUDGED TEMPERATURES
UP A TAD FOR FRIDAY AS IT DOES LOOK LIKE THE COOLER AIR WILL HANG
BACK ONE MORE DAY. AM STILL CONCERNED THAT FRIDAY MAY INDEED BE
WARMER THAN CURRENTLY FORECAST WITH COMPRESSIONAL WARMING AHEAD OF
THE APPROACHING FRONT/TROUGH. MOISTURE WILL RIDE ALONG OUR
NORTHWESTERN ZONES FOR FRIDAY AFTERNOON AND SATURDAY.
THEREFORE...HAVE INCREASED PRECIP CHANCES OVER YELLOWSTONE AND THE
SURROUNDING MOUNTAINS. ENERGY IN THE BASE OF THE TROUGH WILL BEGIN
TO EJECT SATURDAY WHILE AT THE SAME TIME A SURFACE LOW TAKES SHAPE
TO OUR SOUTHEAST. THIS WILL BRING THE COLD FRONT ACROSS THE
FORECAST AREA SATURDAY. BOTH THE ECMWF AND GFS HAVE THE FORECAST
AREA DRY SLOTTED SATURDAY AS THE UPPER LOW TRACKS TO OUR NORTH.
BEST CHANCE FOR MEASURABLE PRECIP OVER THE WEEKEND WILL BE ACROSS
THE NORTHERN THIRD OF THE FORECAST AREA CLOSEST TO THE UPPER LOW.
SURFACE HIGH PUSHES INTO WYOMING SUNDAY AND 700MB TEMPERATURES
FALL INTO THE ZERO TO +4C RANGE ACROSS THE NORTH. THIS WILL LEAD
TO COOLER THAN AVERAGE TEMPERATURES FOR SUNDAY IN ALL BUT
SOUTHWEST AND FAR WEST WYOMING.

AVIATION.../00Z ISSUANCE/

A COLD FRONT WILL CONTINUE TO PUSH EAST ACROSS THE INTERMOUNTAIN
WEST WITH SFC WINDS GENERALLY FROM THE SOUTHWEST TO WEST ACROSS MUCH
OF THE STATE AHEAD OF THE COLD FRONT...WINDS WILL BRIEFLY SWITCH TO
THE NW BEHIND THE FRONT WITH SOME AREAS OF 30-40KT GUSTS BEHIND THE
FRONT VCNTY KBYG KPOY KU68. THE MAIN AREA OF ISOLD-SCT -TSRA VCNTY
AND SOUTH OF A KEVW- KLND- KCPR LINE WITH HIGH BASED WINDY STORMS
EXPECTED INTO THE EARLY EVENING. THE COLD FRONT WILL BRING DRIER AIR
AND GUSTY WEST WIND INTO NW WYOMING MID TO LATE THIS
AFTERNOON...PUSHING ACROSS NORTH AND CENTRAL WYOMING LATE THIS
EVENING. CLEAR SKIES AND DIMINISHING WIND WILL PREVAIL ACROSS THE
AREA BEHIND THE FRONT EARLY MONDAY MORNING.

FIRE WEATHER...

..RED FLAG WARNING FOR PORTIONS OF CENTRAL AND NORTHERN WYOMING
THROUGH THE EVENING HOURS...

A COLD FRONT ASSOCIATED WITH THE TROUGH DIGGING TO THE WEST REMAINS
IN THE AREA NEAR THE MONTANA BORDER THIS AFTERNOON WITH COOLER
TEMPERATURES AND MODERATE HUMIDITY TO THE NORTH OF IT AND RED FLAG
TO NEAR RED FLAG CONDITIONS JUST TO THE SOUTH OF IT. MODELS ARE
CALLING FOR SOUTHWEST FLOW TO OVERTAKE THE FRONT AND CAUSE IT TO
RETREAT BACK NORTH FOR THE LATE AFTERNOON HOURS. THE MAIN FRONTAL
SURGE WILL COME LATER TONIGHT WITH STEADY 25 TO 35 MPH WINDS IN
JOHNSON COUNTY AND NORTHERN BIGHORN COUNTY BEHIND THE
FRONT...EXTENDED THE NORTHERN RED FLAG WARNINGS TO 3AM TO COVER THE
FRONTAL PASSAGE THOUGH IT MAY HAPPEN SOONER.

IN ADDITION...ISOLATED TO WIDELY SCATTERED MIXED WET AND DRY
THUNDERSTORMS ARE EXPECTED TO CONTINUE TO DEVELOP INTO THE EVENING
HOURS...WITH A FEW PERSISTING INTO THE NIGHT...ESPECIALLY EAST OF
THE DIVIDE.

IT WILL BE DRY BEHIND THE FRONT FOR MONDAY BUT A BIT COOLER. THERE
WILL BE SOME 20MPH BREEZES IN THE AFTERNOON BUT RED FLAG CONDITIONS
ARE NOT EXPECTED.

IT SILL LOOKS LIKE THERE COULD BE WIDESPREAD RED FLAG CONDITIONS MID
WEEK...STAY TUNED FOR UPDATES ON THE NEXT SYSTEM.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...
RED FLAG WARNING UNTIL 3 AM MDT MONDAY FOR WYZ275-276-281-282-
287.

&&

$$

UPDATE...AEM
SHORT TERM...ALLEN
LONG TERM...CNJ
AVIATION...ALLEN
FIRE WEATHER...ALLEN



000
FXUS63 KUNR 310205
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
805 PM MDT SUN AUG 30 2015

.UPDATE...
ISSUED AT 802 PM MDT SUN AUG 30 2015

01Z SURFACE ANALYSIS HAD FRONTAL BOUNDARY FROM CENTRAL ND INTO
CENTRAL WY WITH PREFRONTAL TROUGH FROM CENTRAL ND INTO WESTERN NE.
DEEP DAYTIME MIXING ALONG WITH INCREASE IN MID-LEVEL MOISTURE PER
WATER VAPOUR RESULTED IN MAINLY HIGH-BASED -SHRA/-TSRA ALONG THE
FRONTAL BOUNDARY THIS EVENING...WHICH ARE NOW MOVING NORTHEAST
UNDER MEAN FLOW ALOFT. ACTIVITY WILL SLOWLY WANE OVERNIGHT. UPDATE
TO ADDRESS LATEST TRENDS IN TIMING.

&&

.SHORT TERM...THIS EVENING THROUGH MONDAY NIGHT
ISSUED AT 300 PM MDT SUN AUG 30 2015

CURRENT SURFACE ANALYSIS SHOWS SLOW MOVING COLD FRONT FROM FAR
EASTERN MT THROUGH NORTHEAST INTO CENTRAL WY. UPPER LEVEL ANALYSIS
SHOWS POSITIVELY TILTED RIDGE FROM THE SOUTHERN ROCKIES INTO
EASTERN PORTIONS OF THE NORTHERN PLAINS. SOUTHWEST FLOW ALOFT
BEHIND THE RIDGE FROM THE GREAT BASIN TO THE NORTHERN HIGH PLAINS.
SKIES ARE MOSTLY SUNNY ACROSS EASTERN PORTIONS OF THE CWA...PARTLY
CLOUDY OVER NORTHEAST WY. REGIONAL RADARS SHOW BULK OF SHOWER AND
THUNDERSTORM ACTIVITY OVER NORTHEAST MT INTO NORTHWEST ND NEAR THE
FRONT...AS WELL AS OVER THE HIGHER TERRAIN OF CENTRAL WY. A FEW
SHOWERS AND STORMS ARE NOW DEVELOPING NEAR AND AHEAD OF THE FRONT
OVER NORTHEAST WY. TEMPS ARE IN THE 90S OVER MUCH OF THE
AREA...WITH SOME 80S OVER THE BLACK HILLS. WINDS ARE FROM THE
SOUTH TO SOUTHWEST... BREEZY OVER SOUTH CENTRAL SD AS WELL AS
PORTIONS OF NORTHEAST WY.

COLD FRONT WILL EVER SO SLOWLY CROSS THE FORECAST AREA LATE TODAY
AND TONIGHT...WEAKENING SOME AS IT REACHES SOUTH CENTRAL SD MONDAY
MORNING. MOSTLY ISOLATED SHOWERS AND THUNDERSTORMS CAN BE EXPECTED
WITH THE FRONTAL PASSAGE TONIGHT. THE BEST CHANCES WILL LIKELY BE
OVER FAR NORTHWEST SD THIS EVENING. THE THREAT FOR ANY STRONGER
STORMS WILL BE MINIMAL THROUGH THE EVENING AS CAPE VALUES REMAIN
RELATIVELY LOW ACROSS THE AREA...BUT SOME GUSTY WINDS ARE POSSIBLE.
WINDS WILL SWITCH TO THE WEST AND NORTHWEST BEHIND THE
FRONT...BECOMING BREEZY LATER TONIGHT AND EARLY MONDAY OVER MUCH OF
THE PLAINS. AHEAD OF THE FRONT...WINDS WILL REMAIN BREEZY FROM THE
SOUTH OVER SOUTH CENTRAL SD. LOWS WILL RANGE FROM THE 50S OVER
NORTHEAST WY AND THE BLACK HILLS TO AROUND 70 OVER SOUTH CENTRAL SD.

FRONT WILL SLOWLY SAG SOUTH AND EAST OF THE AREA ON MONDAY AND
FURTHER WEAKEN. WOULD NOT BE SURPRISED TO SEE A SHOWER OR
THUNDERSTORM OVER FAR SOUTHERN SD ON MONDAY IN CLOSER VICINITY TO
THE FRONT...ESPECIALLY SOUTH CENTRAL SD...BUT CHANCES LOOK BELOW 15
PERCENT SO WILL LEAVE FORECAST DRY. SOME COOLER AIR WILL BUILD INTO
THE AREA...WITH HIGHS IN THE 80S ACROSS THE PLAINS...70S IN THE
BLACK HILLS. BRISK NORTHWEST WINDS CAN BE EXPECTED ACROSS THE SD
PLAINS DURING THE DAY. MOSTLY CLEAR MONDAY NIGHT WITH LOWS NEAR OR
SLIGHTLY ABOVE SEASONAL AVERAGES.

.LONG TERM...TUESDAY THROUGH SUNDAY
ISSUED AT 300 PM MDT SUN AUG 30 2015

LONG WAVE TROUGH OVER WESTERN NOAM WILL REMAIN THROUGH
MID WEEK...WITH EVENTUAL BREAKDOWN PER AN ADVECTING STRONG NORTHERN
PAC IMPULSE. THIS WILL SUPPORT VERY WARM TEMPS THROUGH THURS. STRONG
SUPPORT AMONG DETERMINISTIC AND ENSEMBLE MODEL RUNS FOR A STRONG
COLD FRONT TO ADVECT TROUGH THE REGION NEXT WEEKEND AS THE PAC NW
UPPER TROUGH MERGES WITH A STRONG CENTRAL CANADIAN TROUGH.
HOWEVER...PRECIP CHANCES STILL LOOK LOW GIVEN LACK OF SUFFICIENT
MOISTURE WITH THE BULK OF LSA SHIFTING NORTH OF THE AREA. MUCH
COOLER TEMPS LOOK MORE LIKELY BY SUN-MON NEXT WEEK WITH HIGHS IN THE
50S-60S POSSIBLE BY THEN. MEANWHILE...DRY WEATHER IS EXPECTED TUE-
THUR...ALTHOUGH A WEAK SIGNAL REMAINS OVER SCENTRAL SD TUES WHERE A
LL TROUGH AND MOISTURE ADV ARE PROGGED. DID BUMPS TEMPS UP TUE-THUR
GIVEN WARM-DRY SW FLOW WITH WARMER TEMPS NOW PROGGED IN CONSENSUS
BLENDS. OTHERWISE...COOLER CONDS WILL ARRIVE FRI-SAT...HOW COOL WILL
DEPEND ON THE PROGRESSIVE NATURE OF THE UPPER TROUGH...WHICH IS A
LITTLE SLOWER IN THE ECMWF. MUCH COOLER CONDS EXPECTED BY EARLY NEXT
WEEK...ALONG WITH ISOLD-SCT SHRA.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING)
ISSUED AT 520 PM MDT SUN AUG 30 2015

A COOL FRONT WILL SLOWLY SLIDE SOUTHEAST THROUGH THE CWA TONIGHT
INTO MONDAY MORNING. GUSTY SOUTHERLY WINDS ARE EXPECTED AHEAD OF
IT WITH GUSTY NORTHWEST WINDS BEHIND IT. ISOLATED HIGH BASED -TSRA
ARE POSSIBLE NEAR THE FRONT TONIGHT WITH ISOLATED WIND GUSTS
AROUND 40KTS. VFR CIGS/VSBYS ARE EXPECTED THROUGH THE PERIOD.

&&

.FIRE WEATHER...
ISSUED AT 300 PM MDT SUN AUG 30 2015

WARM AND DRY CONDITIONS WILL PERSIST ACROSS NE WY THIS
AFTERNOON...WITH RELATIVE HUMIDITY AROUND 15 PERCENT AND GUSTY
WESTERLY WINDS OF 20 TO 30 MPH. A FEW ISOLD TS ARE ALSO POSSIBLE
WITH DRY LIGHTNING AND GUSTY WINDS LIKELY WITH ANY TS. A COLD
FRONT WILL CROSS THE AREA TONIGHT WITH WINDS SHIFTING NW AND
REMAINING GUSTY FOR A FEW HOURS.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
WY...NONE.
&&

$$

UPDATE...HELGESON
SHORT TERM...26
LONG TERM...JC
AVIATION...HELGESON
FIRE WEATHER...JC



000
FXUS63 KUNR 310205
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
805 PM MDT SUN AUG 30 2015

.UPDATE...
ISSUED AT 802 PM MDT SUN AUG 30 2015

01Z SURFACE ANALYSIS HAD FRONTAL BOUNDARY FROM CENTRAL ND INTO
CENTRAL WY WITH PREFRONTAL TROUGH FROM CENTRAL ND INTO WESTERN NE.
DEEP DAYTIME MIXING ALONG WITH INCREASE IN MID-LEVEL MOISTURE PER
WATER VAPOUR RESULTED IN MAINLY HIGH-BASED -SHRA/-TSRA ALONG THE
FRONTAL BOUNDARY THIS EVENING...WHICH ARE NOW MOVING NORTHEAST
UNDER MEAN FLOW ALOFT. ACTIVITY WILL SLOWLY WANE OVERNIGHT. UPDATE
TO ADDRESS LATEST TRENDS IN TIMING.

&&

.SHORT TERM...THIS EVENING THROUGH MONDAY NIGHT
ISSUED AT 300 PM MDT SUN AUG 30 2015

CURRENT SURFACE ANALYSIS SHOWS SLOW MOVING COLD FRONT FROM FAR
EASTERN MT THROUGH NORTHEAST INTO CENTRAL WY. UPPER LEVEL ANALYSIS
SHOWS POSITIVELY TILTED RIDGE FROM THE SOUTHERN ROCKIES INTO
EASTERN PORTIONS OF THE NORTHERN PLAINS. SOUTHWEST FLOW ALOFT
BEHIND THE RIDGE FROM THE GREAT BASIN TO THE NORTHERN HIGH PLAINS.
SKIES ARE MOSTLY SUNNY ACROSS EASTERN PORTIONS OF THE CWA...PARTLY
CLOUDY OVER NORTHEAST WY. REGIONAL RADARS SHOW BULK OF SHOWER AND
THUNDERSTORM ACTIVITY OVER NORTHEAST MT INTO NORTHWEST ND NEAR THE
FRONT...AS WELL AS OVER THE HIGHER TERRAIN OF CENTRAL WY. A FEW
SHOWERS AND STORMS ARE NOW DEVELOPING NEAR AND AHEAD OF THE FRONT
OVER NORTHEAST WY. TEMPS ARE IN THE 90S OVER MUCH OF THE
AREA...WITH SOME 80S OVER THE BLACK HILLS. WINDS ARE FROM THE
SOUTH TO SOUTHWEST... BREEZY OVER SOUTH CENTRAL SD AS WELL AS
PORTIONS OF NORTHEAST WY.

COLD FRONT WILL EVER SO SLOWLY CROSS THE FORECAST AREA LATE TODAY
AND TONIGHT...WEAKENING SOME AS IT REACHES SOUTH CENTRAL SD MONDAY
MORNING. MOSTLY ISOLATED SHOWERS AND THUNDERSTORMS CAN BE EXPECTED
WITH THE FRONTAL PASSAGE TONIGHT. THE BEST CHANCES WILL LIKELY BE
OVER FAR NORTHWEST SD THIS EVENING. THE THREAT FOR ANY STRONGER
STORMS WILL BE MINIMAL THROUGH THE EVENING AS CAPE VALUES REMAIN
RELATIVELY LOW ACROSS THE AREA...BUT SOME GUSTY WINDS ARE POSSIBLE.
WINDS WILL SWITCH TO THE WEST AND NORTHWEST BEHIND THE
FRONT...BECOMING BREEZY LATER TONIGHT AND EARLY MONDAY OVER MUCH OF
THE PLAINS. AHEAD OF THE FRONT...WINDS WILL REMAIN BREEZY FROM THE
SOUTH OVER SOUTH CENTRAL SD. LOWS WILL RANGE FROM THE 50S OVER
NORTHEAST WY AND THE BLACK HILLS TO AROUND 70 OVER SOUTH CENTRAL SD.

FRONT WILL SLOWLY SAG SOUTH AND EAST OF THE AREA ON MONDAY AND
FURTHER WEAKEN. WOULD NOT BE SURPRISED TO SEE A SHOWER OR
THUNDERSTORM OVER FAR SOUTHERN SD ON MONDAY IN CLOSER VICINITY TO
THE FRONT...ESPECIALLY SOUTH CENTRAL SD...BUT CHANCES LOOK BELOW 15
PERCENT SO WILL LEAVE FORECAST DRY. SOME COOLER AIR WILL BUILD INTO
THE AREA...WITH HIGHS IN THE 80S ACROSS THE PLAINS...70S IN THE
BLACK HILLS. BRISK NORTHWEST WINDS CAN BE EXPECTED ACROSS THE SD
PLAINS DURING THE DAY. MOSTLY CLEAR MONDAY NIGHT WITH LOWS NEAR OR
SLIGHTLY ABOVE SEASONAL AVERAGES.

.LONG TERM...TUESDAY THROUGH SUNDAY
ISSUED AT 300 PM MDT SUN AUG 30 2015

LONG WAVE TROUGH OVER WESTERN NOAM WILL REMAIN THROUGH
MID WEEK...WITH EVENTUAL BREAKDOWN PER AN ADVECTING STRONG NORTHERN
PAC IMPULSE. THIS WILL SUPPORT VERY WARM TEMPS THROUGH THURS. STRONG
SUPPORT AMONG DETERMINISTIC AND ENSEMBLE MODEL RUNS FOR A STRONG
COLD FRONT TO ADVECT TROUGH THE REGION NEXT WEEKEND AS THE PAC NW
UPPER TROUGH MERGES WITH A STRONG CENTRAL CANADIAN TROUGH.
HOWEVER...PRECIP CHANCES STILL LOOK LOW GIVEN LACK OF SUFFICIENT
MOISTURE WITH THE BULK OF LSA SHIFTING NORTH OF THE AREA. MUCH
COOLER TEMPS LOOK MORE LIKELY BY SUN-MON NEXT WEEK WITH HIGHS IN THE
50S-60S POSSIBLE BY THEN. MEANWHILE...DRY WEATHER IS EXPECTED TUE-
THUR...ALTHOUGH A WEAK SIGNAL REMAINS OVER SCENTRAL SD TUES WHERE A
LL TROUGH AND MOISTURE ADV ARE PROGGED. DID BUMPS TEMPS UP TUE-THUR
GIVEN WARM-DRY SW FLOW WITH WARMER TEMPS NOW PROGGED IN CONSENSUS
BLENDS. OTHERWISE...COOLER CONDS WILL ARRIVE FRI-SAT...HOW COOL WILL
DEPEND ON THE PROGRESSIVE NATURE OF THE UPPER TROUGH...WHICH IS A
LITTLE SLOWER IN THE ECMWF. MUCH COOLER CONDS EXPECTED BY EARLY NEXT
WEEK...ALONG WITH ISOLD-SCT SHRA.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING)
ISSUED AT 520 PM MDT SUN AUG 30 2015

A COOL FRONT WILL SLOWLY SLIDE SOUTHEAST THROUGH THE CWA TONIGHT
INTO MONDAY MORNING. GUSTY SOUTHERLY WINDS ARE EXPECTED AHEAD OF
IT WITH GUSTY NORTHWEST WINDS BEHIND IT. ISOLATED HIGH BASED -TSRA
ARE POSSIBLE NEAR THE FRONT TONIGHT WITH ISOLATED WIND GUSTS
AROUND 40KTS. VFR CIGS/VSBYS ARE EXPECTED THROUGH THE PERIOD.

&&

.FIRE WEATHER...
ISSUED AT 300 PM MDT SUN AUG 30 2015

WARM AND DRY CONDITIONS WILL PERSIST ACROSS NE WY THIS
AFTERNOON...WITH RELATIVE HUMIDITY AROUND 15 PERCENT AND GUSTY
WESTERLY WINDS OF 20 TO 30 MPH. A FEW ISOLD TS ARE ALSO POSSIBLE
WITH DRY LIGHTNING AND GUSTY WINDS LIKELY WITH ANY TS. A COLD
FRONT WILL CROSS THE AREA TONIGHT WITH WINDS SHIFTING NW AND
REMAINING GUSTY FOR A FEW HOURS.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
WY...NONE.
&&

$$

UPDATE...HELGESON
SHORT TERM...26
LONG TERM...JC
AVIATION...HELGESON
FIRE WEATHER...JC




000
FXUS63 KUNR 302322
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
522 PM MDT SUN AUG 30 2015

.SHORT TERM...THIS EVENING THROUGH MONDAY NIGHT
ISSUED AT 300 PM MDT SUN AUG 30 2015

CURRENT SURFACE ANALYSIS SHOWS SLOW MOVING COLD FRONT FROM FAR
EASTERN MT THROUGH NORTHEAST INTO CENTRAL WY. UPPER LEVEL ANALYSIS
SHOWS POSITIVELY TILTED RIDGE FROM THE SOUTHERN ROCKIES INTO
EASTERN PORTIONS OF THE NORTHERN PLAINS. SOUTHWEST FLOW ALOFT
BEHIND THE RIDGE FROM THE GREAT BASIN TO THE NORTHERN HIGH PLAINS.
SKIES ARE MOSTLY SUNNY ACROSS EASTERN PORTIONS OF THE CWA...PARTLY
CLOUDY OVER NORTHEAST WY. REGIONAL RADARS SHOW BULK OF SHOWER AND
THUNDERSTORM ACTIVITY OVER NORTHEAST MT INTO NORTHWEST ND NEAR THE
FRONT...AS WELL AS OVER THE HIGHER TERRAIN OF CENTRAL WY. A FEW
SHOWERS AND STORMS ARE NOW DEVELOPING NEAR AND AHEAD OF THE FRONT
OVER NORTHEAST WY. TEMPS ARE IN THE 90S OVER MUCH OF THE
AREA...WITH SOME 80S OVER THE BLACK HILLS. WINDS ARE FROM THE
SOUTH TO SOUTHWEST... BREEZY OVER SOUTH CENTRAL SD AS WELL AS
PORTIONS OF NORTHEAST WY.

COLD FRONT WILL EVER SO SLOWLY CROSS THE FORECAST AREA LATE TODAY
AND TONIGHT...WEAKENING SOME AS IT REACHES SOUTH CENTRAL SD MONDAY
MORNING. MOSTLY ISOLATED SHOWERS AND THUNDERSTORMS CAN BE EXPECTED
WITH THE FRONTAL PASSAGE TONIGHT. THE BEST CHANCES WILL LIKELY BE
OVER FAR NORTHWEST SD THIS EVENING. THE THREAT FOR ANY STRONGER
STORMS WILL BE MINIMAL THROUGH THE EVENING AS CAPE VALUES REMAIN
RELATIVELY LOW ACROSS THE AREA...BUT SOME GUSTY WINDS ARE POSSIBLE.
WINDS WILL SWITCH TO THE WEST AND NORTHWEST BEHIND THE
FRONT...BECOMING BREEZY LATER TONIGHT AND EARLY MONDAY OVER MUCH OF
THE PLAINS. AHEAD OF THE FRONT...WINDS WILL REMAIN BREEZY FROM THE
SOUTH OVER SOUTH CENTRAL SD. LOWS WILL RANGE FROM THE 50S OVER
NORTHEAST WY AND THE BLACK HILLS TO AROUND 70 OVER SOUTH CENTRAL SD.

FRONT WILL SLOWLY SAG SOUTH AND EAST OF THE AREA ON MONDAY AND
FURTHER WEAKEN. WOULD NOT BE SURPRISED TO SEE A SHOWER OR
THUNDERSTORM OVER FAR SOUTHERN SD ON MONDAY IN CLOSER VICINITY TO
THE FRONT...ESPECIALLY SOUTH CENTRAL SD...BUT CHANCES LOOK BELOW 15
PERCENT SO WILL LEAVE FORECAST DRY. SOME COOLER AIR WILL BUILD INTO
THE AREA...WITH HIGHS IN THE 80S ACROSS THE PLAINS...70S IN THE
BLACK HILLS. BRISK NORTHWEST WINDS CAN BE EXPECTED ACROSS THE SD
PLAINS DURING THE DAY. MOSTLY CLEAR MONDAY NIGHT WITH LOWS NEAR OR
SLIGHTLY ABOVE SEASONAL AVERAGES.

.LONG TERM...TUESDAY THROUGH SUNDAY
ISSUED AT 300 PM MDT SUN AUG 30 2015

LONG WAVE TROUGH OVER WESTERN NOAM WILL REMAIN THROUGH
MID WEEK...WITH EVENTUAL BREAKDOWN PER AN ADVECTING STRONG NORTHERN
PAC IMPULSE. THIS WILL SUPPORT VERY WARM TEMPS THROUGH THURS. STRONG
SUPPORT AMONG DETERMINISTIC AND ENSEMBLE MODEL RUNS FOR A STRONG
COLD FRONT TO ADVECT TROUGH THE REGION NEXT WEEKEND AS THE PAC NW
UPPER TROUGH MERGES WITH A STRONG CENTRAL CANADIAN TROUGH.
HOWEVER...PRECIP CHANCES STILL LOOK LOW GIVEN LACK OF SUFFICIENT
MOISTURE WITH THE BULK OF LSA SHIFTING NORTH OF THE AREA. MUCH
COOLER TEMPS LOOK MORE LIKELY BY SUN-MON NEXT WEEK WITH HIGHS IN THE
50S-60S POSSIBLE BY THEN. MEANWHILE...DRY WEATHER IS EXPECTED TUE-
THUR...ALTHOUGH A WEAK SIGNAL REMAINS OVER SCENTRAL SD TUES WHERE A
LL TROUGH AND MOISTURE ADV ARE PROGGED. DID BUMPS TEMPS UP TUE-THUR
GIVEN WARM-DRY SW FLOW WITH WARMER TEMPS NOW PROGGED IN CONSENSUS
BLENDS. OTHERWISE...COOLER CONDS WILL ARRIVE FRI-SAT...HOW COOL WILL
DEPEND ON THE PROGRESSIVE NATURE OF THE UPPER TROUGH...WHICH IS A
LITTLE SLOWER IN THE ECMWF. MUCH COOLER CONDS EXPECTED BY EARLY NEXT
WEEK...ALONG WITH ISOLD-SCT SHRA.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING)
ISSUED AT 520 PM MDT SUN AUG 30 2015

A COOL FRONT WILL SLOWLY SLIDE SOUTHEAST THROUGH THE CWA TONIGHT
INTO MONDAY MORNING. GUSTY SOUTHERLY WINDS ARE EXPECTED AHEAD OF
IT WITH GUSTY NORTHWEST WINDS BEHIND IT. ISOLATED HIGH BASED -TSRA
ARE POSSIBLE NEAR THE FRONT TONIGHT WITH ISOLATED WIND GUSTS
AROUND 40KTS. VFR CIGS/VSBYS ARE EXPECTED THROUGH THE PERIOD.

&&

.FIRE WEATHER...
ISSUED AT 300 PM MDT SUN AUG 30 2015

WARM AND DRY CONDITIONS WILL PERSIST ACROSS NE WY THIS
AFTERNOON...WITH RELATIVE HUMIDITY AROUND 15 PERCENT AND GUSTY
WESTERLY WINDS OF 20 TO 30 MPH. A FEW ISOLD TS ARE ALSO POSSIBLE
WITH DRY LIGHTNING AND GUSTY WINDS LIKELY WITH ANY TS. A COLD
FRONT WILL CROSS THE AREA TONIGHT WITH WINDS SHIFTING NW AND
REMAINING GUSTY FOR A FEW HOURS.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
WY...RED FLAG WARNING UNTIL 8 PM MDT THIS EVENING FOR WYZ259-297-298.

&&

$$

SHORT TERM...26
LONG TERM...JC
AVIATION...HELGESON
FIRE WEATHER...JC



000
FXUS63 KUNR 302322
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
522 PM MDT SUN AUG 30 2015

.SHORT TERM...THIS EVENING THROUGH MONDAY NIGHT
ISSUED AT 300 PM MDT SUN AUG 30 2015

CURRENT SURFACE ANALYSIS SHOWS SLOW MOVING COLD FRONT FROM FAR
EASTERN MT THROUGH NORTHEAST INTO CENTRAL WY. UPPER LEVEL ANALYSIS
SHOWS POSITIVELY TILTED RIDGE FROM THE SOUTHERN ROCKIES INTO
EASTERN PORTIONS OF THE NORTHERN PLAINS. SOUTHWEST FLOW ALOFT
BEHIND THE RIDGE FROM THE GREAT BASIN TO THE NORTHERN HIGH PLAINS.
SKIES ARE MOSTLY SUNNY ACROSS EASTERN PORTIONS OF THE CWA...PARTLY
CLOUDY OVER NORTHEAST WY. REGIONAL RADARS SHOW BULK OF SHOWER AND
THUNDERSTORM ACTIVITY OVER NORTHEAST MT INTO NORTHWEST ND NEAR THE
FRONT...AS WELL AS OVER THE HIGHER TERRAIN OF CENTRAL WY. A FEW
SHOWERS AND STORMS ARE NOW DEVELOPING NEAR AND AHEAD OF THE FRONT
OVER NORTHEAST WY. TEMPS ARE IN THE 90S OVER MUCH OF THE
AREA...WITH SOME 80S OVER THE BLACK HILLS. WINDS ARE FROM THE
SOUTH TO SOUTHWEST... BREEZY OVER SOUTH CENTRAL SD AS WELL AS
PORTIONS OF NORTHEAST WY.

COLD FRONT WILL EVER SO SLOWLY CROSS THE FORECAST AREA LATE TODAY
AND TONIGHT...WEAKENING SOME AS IT REACHES SOUTH CENTRAL SD MONDAY
MORNING. MOSTLY ISOLATED SHOWERS AND THUNDERSTORMS CAN BE EXPECTED
WITH THE FRONTAL PASSAGE TONIGHT. THE BEST CHANCES WILL LIKELY BE
OVER FAR NORTHWEST SD THIS EVENING. THE THREAT FOR ANY STRONGER
STORMS WILL BE MINIMAL THROUGH THE EVENING AS CAPE VALUES REMAIN
RELATIVELY LOW ACROSS THE AREA...BUT SOME GUSTY WINDS ARE POSSIBLE.
WINDS WILL SWITCH TO THE WEST AND NORTHWEST BEHIND THE
FRONT...BECOMING BREEZY LATER TONIGHT AND EARLY MONDAY OVER MUCH OF
THE PLAINS. AHEAD OF THE FRONT...WINDS WILL REMAIN BREEZY FROM THE
SOUTH OVER SOUTH CENTRAL SD. LOWS WILL RANGE FROM THE 50S OVER
NORTHEAST WY AND THE BLACK HILLS TO AROUND 70 OVER SOUTH CENTRAL SD.

FRONT WILL SLOWLY SAG SOUTH AND EAST OF THE AREA ON MONDAY AND
FURTHER WEAKEN. WOULD NOT BE SURPRISED TO SEE A SHOWER OR
THUNDERSTORM OVER FAR SOUTHERN SD ON MONDAY IN CLOSER VICINITY TO
THE FRONT...ESPECIALLY SOUTH CENTRAL SD...BUT CHANCES LOOK BELOW 15
PERCENT SO WILL LEAVE FORECAST DRY. SOME COOLER AIR WILL BUILD INTO
THE AREA...WITH HIGHS IN THE 80S ACROSS THE PLAINS...70S IN THE
BLACK HILLS. BRISK NORTHWEST WINDS CAN BE EXPECTED ACROSS THE SD
PLAINS DURING THE DAY. MOSTLY CLEAR MONDAY NIGHT WITH LOWS NEAR OR
SLIGHTLY ABOVE SEASONAL AVERAGES.

.LONG TERM...TUESDAY THROUGH SUNDAY
ISSUED AT 300 PM MDT SUN AUG 30 2015

LONG WAVE TROUGH OVER WESTERN NOAM WILL REMAIN THROUGH
MID WEEK...WITH EVENTUAL BREAKDOWN PER AN ADVECTING STRONG NORTHERN
PAC IMPULSE. THIS WILL SUPPORT VERY WARM TEMPS THROUGH THURS. STRONG
SUPPORT AMONG DETERMINISTIC AND ENSEMBLE MODEL RUNS FOR A STRONG
COLD FRONT TO ADVECT TROUGH THE REGION NEXT WEEKEND AS THE PAC NW
UPPER TROUGH MERGES WITH A STRONG CENTRAL CANADIAN TROUGH.
HOWEVER...PRECIP CHANCES STILL LOOK LOW GIVEN LACK OF SUFFICIENT
MOISTURE WITH THE BULK OF LSA SHIFTING NORTH OF THE AREA. MUCH
COOLER TEMPS LOOK MORE LIKELY BY SUN-MON NEXT WEEK WITH HIGHS IN THE
50S-60S POSSIBLE BY THEN. MEANWHILE...DRY WEATHER IS EXPECTED TUE-
THUR...ALTHOUGH A WEAK SIGNAL REMAINS OVER SCENTRAL SD TUES WHERE A
LL TROUGH AND MOISTURE ADV ARE PROGGED. DID BUMPS TEMPS UP TUE-THUR
GIVEN WARM-DRY SW FLOW WITH WARMER TEMPS NOW PROGGED IN CONSENSUS
BLENDS. OTHERWISE...COOLER CONDS WILL ARRIVE FRI-SAT...HOW COOL WILL
DEPEND ON THE PROGRESSIVE NATURE OF THE UPPER TROUGH...WHICH IS A
LITTLE SLOWER IN THE ECMWF. MUCH COOLER CONDS EXPECTED BY EARLY NEXT
WEEK...ALONG WITH ISOLD-SCT SHRA.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING)
ISSUED AT 520 PM MDT SUN AUG 30 2015

A COOL FRONT WILL SLOWLY SLIDE SOUTHEAST THROUGH THE CWA TONIGHT
INTO MONDAY MORNING. GUSTY SOUTHERLY WINDS ARE EXPECTED AHEAD OF
IT WITH GUSTY NORTHWEST WINDS BEHIND IT. ISOLATED HIGH BASED -TSRA
ARE POSSIBLE NEAR THE FRONT TONIGHT WITH ISOLATED WIND GUSTS
AROUND 40KTS. VFR CIGS/VSBYS ARE EXPECTED THROUGH THE PERIOD.

&&

.FIRE WEATHER...
ISSUED AT 300 PM MDT SUN AUG 30 2015

WARM AND DRY CONDITIONS WILL PERSIST ACROSS NE WY THIS
AFTERNOON...WITH RELATIVE HUMIDITY AROUND 15 PERCENT AND GUSTY
WESTERLY WINDS OF 20 TO 30 MPH. A FEW ISOLD TS ARE ALSO POSSIBLE
WITH DRY LIGHTNING AND GUSTY WINDS LIKELY WITH ANY TS. A COLD
FRONT WILL CROSS THE AREA TONIGHT WITH WINDS SHIFTING NW AND
REMAINING GUSTY FOR A FEW HOURS.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
WY...RED FLAG WARNING UNTIL 8 PM MDT THIS EVENING FOR WYZ259-297-298.

&&

$$

SHORT TERM...26
LONG TERM...JC
AVIATION...HELGESON
FIRE WEATHER...JC




000
FXUS63 KUNR 302322
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
522 PM MDT SUN AUG 30 2015

.SHORT TERM...THIS EVENING THROUGH MONDAY NIGHT
ISSUED AT 300 PM MDT SUN AUG 30 2015

CURRENT SURFACE ANALYSIS SHOWS SLOW MOVING COLD FRONT FROM FAR
EASTERN MT THROUGH NORTHEAST INTO CENTRAL WY. UPPER LEVEL ANALYSIS
SHOWS POSITIVELY TILTED RIDGE FROM THE SOUTHERN ROCKIES INTO
EASTERN PORTIONS OF THE NORTHERN PLAINS. SOUTHWEST FLOW ALOFT
BEHIND THE RIDGE FROM THE GREAT BASIN TO THE NORTHERN HIGH PLAINS.
SKIES ARE MOSTLY SUNNY ACROSS EASTERN PORTIONS OF THE CWA...PARTLY
CLOUDY OVER NORTHEAST WY. REGIONAL RADARS SHOW BULK OF SHOWER AND
THUNDERSTORM ACTIVITY OVER NORTHEAST MT INTO NORTHWEST ND NEAR THE
FRONT...AS WELL AS OVER THE HIGHER TERRAIN OF CENTRAL WY. A FEW
SHOWERS AND STORMS ARE NOW DEVELOPING NEAR AND AHEAD OF THE FRONT
OVER NORTHEAST WY. TEMPS ARE IN THE 90S OVER MUCH OF THE
AREA...WITH SOME 80S OVER THE BLACK HILLS. WINDS ARE FROM THE
SOUTH TO SOUTHWEST... BREEZY OVER SOUTH CENTRAL SD AS WELL AS
PORTIONS OF NORTHEAST WY.

COLD FRONT WILL EVER SO SLOWLY CROSS THE FORECAST AREA LATE TODAY
AND TONIGHT...WEAKENING SOME AS IT REACHES SOUTH CENTRAL SD MONDAY
MORNING. MOSTLY ISOLATED SHOWERS AND THUNDERSTORMS CAN BE EXPECTED
WITH THE FRONTAL PASSAGE TONIGHT. THE BEST CHANCES WILL LIKELY BE
OVER FAR NORTHWEST SD THIS EVENING. THE THREAT FOR ANY STRONGER
STORMS WILL BE MINIMAL THROUGH THE EVENING AS CAPE VALUES REMAIN
RELATIVELY LOW ACROSS THE AREA...BUT SOME GUSTY WINDS ARE POSSIBLE.
WINDS WILL SWITCH TO THE WEST AND NORTHWEST BEHIND THE
FRONT...BECOMING BREEZY LATER TONIGHT AND EARLY MONDAY OVER MUCH OF
THE PLAINS. AHEAD OF THE FRONT...WINDS WILL REMAIN BREEZY FROM THE
SOUTH OVER SOUTH CENTRAL SD. LOWS WILL RANGE FROM THE 50S OVER
NORTHEAST WY AND THE BLACK HILLS TO AROUND 70 OVER SOUTH CENTRAL SD.

FRONT WILL SLOWLY SAG SOUTH AND EAST OF THE AREA ON MONDAY AND
FURTHER WEAKEN. WOULD NOT BE SURPRISED TO SEE A SHOWER OR
THUNDERSTORM OVER FAR SOUTHERN SD ON MONDAY IN CLOSER VICINITY TO
THE FRONT...ESPECIALLY SOUTH CENTRAL SD...BUT CHANCES LOOK BELOW 15
PERCENT SO WILL LEAVE FORECAST DRY. SOME COOLER AIR WILL BUILD INTO
THE AREA...WITH HIGHS IN THE 80S ACROSS THE PLAINS...70S IN THE
BLACK HILLS. BRISK NORTHWEST WINDS CAN BE EXPECTED ACROSS THE SD
PLAINS DURING THE DAY. MOSTLY CLEAR MONDAY NIGHT WITH LOWS NEAR OR
SLIGHTLY ABOVE SEASONAL AVERAGES.

.LONG TERM...TUESDAY THROUGH SUNDAY
ISSUED AT 300 PM MDT SUN AUG 30 2015

LONG WAVE TROUGH OVER WESTERN NOAM WILL REMAIN THROUGH
MID WEEK...WITH EVENTUAL BREAKDOWN PER AN ADVECTING STRONG NORTHERN
PAC IMPULSE. THIS WILL SUPPORT VERY WARM TEMPS THROUGH THURS. STRONG
SUPPORT AMONG DETERMINISTIC AND ENSEMBLE MODEL RUNS FOR A STRONG
COLD FRONT TO ADVECT TROUGH THE REGION NEXT WEEKEND AS THE PAC NW
UPPER TROUGH MERGES WITH A STRONG CENTRAL CANADIAN TROUGH.
HOWEVER...PRECIP CHANCES STILL LOOK LOW GIVEN LACK OF SUFFICIENT
MOISTURE WITH THE BULK OF LSA SHIFTING NORTH OF THE AREA. MUCH
COOLER TEMPS LOOK MORE LIKELY BY SUN-MON NEXT WEEK WITH HIGHS IN THE
50S-60S POSSIBLE BY THEN. MEANWHILE...DRY WEATHER IS EXPECTED TUE-
THUR...ALTHOUGH A WEAK SIGNAL REMAINS OVER SCENTRAL SD TUES WHERE A
LL TROUGH AND MOISTURE ADV ARE PROGGED. DID BUMPS TEMPS UP TUE-THUR
GIVEN WARM-DRY SW FLOW WITH WARMER TEMPS NOW PROGGED IN CONSENSUS
BLENDS. OTHERWISE...COOLER CONDS WILL ARRIVE FRI-SAT...HOW COOL WILL
DEPEND ON THE PROGRESSIVE NATURE OF THE UPPER TROUGH...WHICH IS A
LITTLE SLOWER IN THE ECMWF. MUCH COOLER CONDS EXPECTED BY EARLY NEXT
WEEK...ALONG WITH ISOLD-SCT SHRA.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING)
ISSUED AT 520 PM MDT SUN AUG 30 2015

A COOL FRONT WILL SLOWLY SLIDE SOUTHEAST THROUGH THE CWA TONIGHT
INTO MONDAY MORNING. GUSTY SOUTHERLY WINDS ARE EXPECTED AHEAD OF
IT WITH GUSTY NORTHWEST WINDS BEHIND IT. ISOLATED HIGH BASED -TSRA
ARE POSSIBLE NEAR THE FRONT TONIGHT WITH ISOLATED WIND GUSTS
AROUND 40KTS. VFR CIGS/VSBYS ARE EXPECTED THROUGH THE PERIOD.

&&

.FIRE WEATHER...
ISSUED AT 300 PM MDT SUN AUG 30 2015

WARM AND DRY CONDITIONS WILL PERSIST ACROSS NE WY THIS
AFTERNOON...WITH RELATIVE HUMIDITY AROUND 15 PERCENT AND GUSTY
WESTERLY WINDS OF 20 TO 30 MPH. A FEW ISOLD TS ARE ALSO POSSIBLE
WITH DRY LIGHTNING AND GUSTY WINDS LIKELY WITH ANY TS. A COLD
FRONT WILL CROSS THE AREA TONIGHT WITH WINDS SHIFTING NW AND
REMAINING GUSTY FOR A FEW HOURS.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
WY...RED FLAG WARNING UNTIL 8 PM MDT THIS EVENING FOR WYZ259-297-298.

&&

$$

SHORT TERM...26
LONG TERM...JC
AVIATION...HELGESON
FIRE WEATHER...JC




000
FXUS63 KUNR 302322
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
522 PM MDT SUN AUG 30 2015

.SHORT TERM...THIS EVENING THROUGH MONDAY NIGHT
ISSUED AT 300 PM MDT SUN AUG 30 2015

CURRENT SURFACE ANALYSIS SHOWS SLOW MOVING COLD FRONT FROM FAR
EASTERN MT THROUGH NORTHEAST INTO CENTRAL WY. UPPER LEVEL ANALYSIS
SHOWS POSITIVELY TILTED RIDGE FROM THE SOUTHERN ROCKIES INTO
EASTERN PORTIONS OF THE NORTHERN PLAINS. SOUTHWEST FLOW ALOFT
BEHIND THE RIDGE FROM THE GREAT BASIN TO THE NORTHERN HIGH PLAINS.
SKIES ARE MOSTLY SUNNY ACROSS EASTERN PORTIONS OF THE CWA...PARTLY
CLOUDY OVER NORTHEAST WY. REGIONAL RADARS SHOW BULK OF SHOWER AND
THUNDERSTORM ACTIVITY OVER NORTHEAST MT INTO NORTHWEST ND NEAR THE
FRONT...AS WELL AS OVER THE HIGHER TERRAIN OF CENTRAL WY. A FEW
SHOWERS AND STORMS ARE NOW DEVELOPING NEAR AND AHEAD OF THE FRONT
OVER NORTHEAST WY. TEMPS ARE IN THE 90S OVER MUCH OF THE
AREA...WITH SOME 80S OVER THE BLACK HILLS. WINDS ARE FROM THE
SOUTH TO SOUTHWEST... BREEZY OVER SOUTH CENTRAL SD AS WELL AS
PORTIONS OF NORTHEAST WY.

COLD FRONT WILL EVER SO SLOWLY CROSS THE FORECAST AREA LATE TODAY
AND TONIGHT...WEAKENING SOME AS IT REACHES SOUTH CENTRAL SD MONDAY
MORNING. MOSTLY ISOLATED SHOWERS AND THUNDERSTORMS CAN BE EXPECTED
WITH THE FRONTAL PASSAGE TONIGHT. THE BEST CHANCES WILL LIKELY BE
OVER FAR NORTHWEST SD THIS EVENING. THE THREAT FOR ANY STRONGER
STORMS WILL BE MINIMAL THROUGH THE EVENING AS CAPE VALUES REMAIN
RELATIVELY LOW ACROSS THE AREA...BUT SOME GUSTY WINDS ARE POSSIBLE.
WINDS WILL SWITCH TO THE WEST AND NORTHWEST BEHIND THE
FRONT...BECOMING BREEZY LATER TONIGHT AND EARLY MONDAY OVER MUCH OF
THE PLAINS. AHEAD OF THE FRONT...WINDS WILL REMAIN BREEZY FROM THE
SOUTH OVER SOUTH CENTRAL SD. LOWS WILL RANGE FROM THE 50S OVER
NORTHEAST WY AND THE BLACK HILLS TO AROUND 70 OVER SOUTH CENTRAL SD.

FRONT WILL SLOWLY SAG SOUTH AND EAST OF THE AREA ON MONDAY AND
FURTHER WEAKEN. WOULD NOT BE SURPRISED TO SEE A SHOWER OR
THUNDERSTORM OVER FAR SOUTHERN SD ON MONDAY IN CLOSER VICINITY TO
THE FRONT...ESPECIALLY SOUTH CENTRAL SD...BUT CHANCES LOOK BELOW 15
PERCENT SO WILL LEAVE FORECAST DRY. SOME COOLER AIR WILL BUILD INTO
THE AREA...WITH HIGHS IN THE 80S ACROSS THE PLAINS...70S IN THE
BLACK HILLS. BRISK NORTHWEST WINDS CAN BE EXPECTED ACROSS THE SD
PLAINS DURING THE DAY. MOSTLY CLEAR MONDAY NIGHT WITH LOWS NEAR OR
SLIGHTLY ABOVE SEASONAL AVERAGES.

.LONG TERM...TUESDAY THROUGH SUNDAY
ISSUED AT 300 PM MDT SUN AUG 30 2015

LONG WAVE TROUGH OVER WESTERN NOAM WILL REMAIN THROUGH
MID WEEK...WITH EVENTUAL BREAKDOWN PER AN ADVECTING STRONG NORTHERN
PAC IMPULSE. THIS WILL SUPPORT VERY WARM TEMPS THROUGH THURS. STRONG
SUPPORT AMONG DETERMINISTIC AND ENSEMBLE MODEL RUNS FOR A STRONG
COLD FRONT TO ADVECT TROUGH THE REGION NEXT WEEKEND AS THE PAC NW
UPPER TROUGH MERGES WITH A STRONG CENTRAL CANADIAN TROUGH.
HOWEVER...PRECIP CHANCES STILL LOOK LOW GIVEN LACK OF SUFFICIENT
MOISTURE WITH THE BULK OF LSA SHIFTING NORTH OF THE AREA. MUCH
COOLER TEMPS LOOK MORE LIKELY BY SUN-MON NEXT WEEK WITH HIGHS IN THE
50S-60S POSSIBLE BY THEN. MEANWHILE...DRY WEATHER IS EXPECTED TUE-
THUR...ALTHOUGH A WEAK SIGNAL REMAINS OVER SCENTRAL SD TUES WHERE A
LL TROUGH AND MOISTURE ADV ARE PROGGED. DID BUMPS TEMPS UP TUE-THUR
GIVEN WARM-DRY SW FLOW WITH WARMER TEMPS NOW PROGGED IN CONSENSUS
BLENDS. OTHERWISE...COOLER CONDS WILL ARRIVE FRI-SAT...HOW COOL WILL
DEPEND ON THE PROGRESSIVE NATURE OF THE UPPER TROUGH...WHICH IS A
LITTLE SLOWER IN THE ECMWF. MUCH COOLER CONDS EXPECTED BY EARLY NEXT
WEEK...ALONG WITH ISOLD-SCT SHRA.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING)
ISSUED AT 520 PM MDT SUN AUG 30 2015

A COOL FRONT WILL SLOWLY SLIDE SOUTHEAST THROUGH THE CWA TONIGHT
INTO MONDAY MORNING. GUSTY SOUTHERLY WINDS ARE EXPECTED AHEAD OF
IT WITH GUSTY NORTHWEST WINDS BEHIND IT. ISOLATED HIGH BASED -TSRA
ARE POSSIBLE NEAR THE FRONT TONIGHT WITH ISOLATED WIND GUSTS
AROUND 40KTS. VFR CIGS/VSBYS ARE EXPECTED THROUGH THE PERIOD.

&&

.FIRE WEATHER...
ISSUED AT 300 PM MDT SUN AUG 30 2015

WARM AND DRY CONDITIONS WILL PERSIST ACROSS NE WY THIS
AFTERNOON...WITH RELATIVE HUMIDITY AROUND 15 PERCENT AND GUSTY
WESTERLY WINDS OF 20 TO 30 MPH. A FEW ISOLD TS ARE ALSO POSSIBLE
WITH DRY LIGHTNING AND GUSTY WINDS LIKELY WITH ANY TS. A COLD
FRONT WILL CROSS THE AREA TONIGHT WITH WINDS SHIFTING NW AND
REMAINING GUSTY FOR A FEW HOURS.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
WY...RED FLAG WARNING UNTIL 8 PM MDT THIS EVENING FOR WYZ259-297-298.

&&

$$

SHORT TERM...26
LONG TERM...JC
AVIATION...HELGESON
FIRE WEATHER...JC



000
FXUS65 KCYS 302319
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
459 PM MDT SUN AUG 30 2015

.UPDATE...
ISSUED AT 455 PM MDT SUN AUG 30 2015

MAY A FEW MINOR ADJUSTMENTS TO THE FORECAST SPREADING CHANCES OF
SHOWERS AND THUNDERSTORMS SLIGHTLY FARTHER EAST INTO THIS EVENING.
ALSO REMOVED THE MENTION OF THUNDERSTORMS AFTER MIDNIGHT.

&&

.SHORT TERM...(THIS EVENING THROUGH TUESDAY NIGHT)

ISSUED AT 300 PM MDT SUN AUG 30 2015

SCATTERED LIGHT SHOWERS AND ISOLATED THUNDERSTORMS WILL
MOVE ACROSS SOUTHEAST WYOMING THIS AFTERNOON AND EVENING. SOME OF
THIS ACTIVITY MAY REACH THE NEBRASKA PANHANDLE. 40 TO 50 SPREADS
BETWEEN TEMPERATURES AND DEWPOINTS WILL MAKE IT TOUGH FOR MOISTURE
TO REACH THE GROUND SUCH THAT MEASURABLE RAIN WILL BE MINIMAL
WHERE IT DOES REACH THE SURFACE. THE LARGE SPREADS BETWEEN
TEMPERATURE AND DEW POINTS WILL PRODUCE THE POTENTIAL FOR
RELATIVELY STRONG DOWN DRAFTS CAPABLE OF PRODUCING WIND GUSTS OF
50 TO 60 MPH...IF NOT GREATER. COW CREEK RAWS ALREADY MEASURED A
GUST OF 54 MPH AT 243 PM. COOLING ALOFT...THE REAR ENTRANCE OF AN
UPPER LEVEL JET...AND MOIST MID FLOW MAY KEEP SOME SHOWER
ACTIVITY LINGERING INTO THE OVERNIGHT HOURS BUT STRONG WIND GUST
POTENTIAL WILL SUBSIDE.

MONDAY WILL SEE A BREAK IN THE VERY WARM TEMPERATURES WITH HIGHS
TYPICALLY IN THE 80S ACROSS THE FORECAST AREA. MID LEVEL MOISTURE
IS PROGGED TO BE IN PLACE ACROSS SOUTHERN PORTIONS OF THE FORECAST
AREA WHICH SHOULD YIELD A FEW MORE AFTERNOON AND EVENING SHOWERS
AND THUNDERSTORMS. AGAIN SEVERE THUNDERSTORMS ARE NOT A CONCERN
BUT A FEW STRONGER WIND GUSTS MAY BE POSSIBLE.

WARMER TEMPERATURES RETURN TUESDAY AS THE RIDGE REBOUNDS ACROSS
THE NORTHERN ROCKIES. HIGH TEMPERATURES TO WARM INTO THE 90S
ACROSS THE PLAINS AND 80S FARTHER WEST. LESSER CHANCES FOR
PRECIPITATION TUESDAY BUT MAY SEE A COUPLE SHOWERS DEVELOP OFF THE
HIGHER TERRAIN.

.LONG TERM...(WEDNESDAY THROUGH SUNDAY)
ISSUED AT 300 PM MDT SUN AUG 30 2015

THERE WILL CONTINUE TO BE SOUTHWESTERLY FLOW ALOFT THROUGHOUT THE
MAJORITY OF THE WEEK. A DRY AIRMASS ALOFT ON WEDNESDAY COULD
BRING CONCERNS FOR FIRE WEATHER WITH RH VALUES DOWN INTO THE MID
TO LOWER TEENS FOR CONVERSE AND NIOBRARA COUNTIES. TEMPERATURES
WILL REMAIN WARM OVER THE COURSE OF THE WEEK WITH POPS BEING LOW.
A FEW ISOLATED THUNDERSTORMS MAY BE SEEN OVER THE SIERRA MADRES
AND SNOWY RANGES ON WEDNESDAY. THURSDAY AND FRIDAY ARE EXPECTED TO
CONTINUE THIS HOT/DRY TREND. THIS PATTERN WILL CHANGE OVER THE
WEEKEND WHEN A UPPER LEVEL TROUGH IS PROJECTED TO MOVE EASTWARD
FROM THE PACIFIC NORTHWEST. A WEAK COLD FRONT PASSAGE ON SATURDAY
WILL BRING SOME SCATTERED SHOWERS AND THUNDERSTORMS...MAINLY
AFFECTING EAST OF THE LARAMIE RANGE INTO THE NEBRASKA PANHANDLE.
THE PASSAGE OF AN UPPER LEVEL TROUGH ON SUNDAY WILL BRING
TEMPERATURES AS WELL AS A CONTINUED CHANCE OF THUNDERSTORMS FOR
THE NEBRASKA PANHANDLE.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY AFTERNOON)
ISSUED AT 459 PM MDT SUN AUG 30 2015

VFR EXPECTED OVER ALL TERMINALS THROUGH THE PERIOD WITH MID LEVEL
CLOUDS SPREADING ACROSS THE AREA. ISOLATED SHOWERS AND TSTMS TONIGHT
WITH BRIEF GUSTY WINDS POSSIBLE AROUND THEM.

&&

.FIRE WEATHER...
ISSUED AT 157 PM MDT SUN AUG 30 2015

MAINLY DRY AND WARM THROUGH THIS WEEK ALTHOUGH THERE WILL
BE SOME CHANCES FOR WETTING RAINS. A FRONTAL BOUNDARY WILL
BRING SCATTERED SHOWERS AND A FEW THUNDERSTORMS TO THE AREA
INTO THIS EVENING. WIND GUSTS TO AROUND 55 MPH WILL OCCUR
WITH SOME SHOWERS AND THUNDERSTORMS INTO THIS EVENING.

COOLER TEMPERATURES MONDAY WILL SUPPRESS CRITICAL FIRE
WEATHER POTENTIAL BUT LATER INTO THE WEEK TEMPERATURES WILL
BE UNSEASONABLY WARM WITH HUMIDITIES DROPPING INTO THE 10
TO 15 PERCENT RANGE ACROSS SOUTHEAST WYOMING. WINDS WILL
BE GUSTY SEVERAL AFTERNOONS DURING THE WEEK SUCH THAT
CRITICAL FIRE THRESHOLDS MAY BE REACHED.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.

NE...NONE.

&&

$$

UPDATE...SML
SHORT TERM...SML
LONG TERM...GCC
AVIATION...RE
FIRE WEATHER...SML



000
FXUS65 KCYS 302319
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
459 PM MDT SUN AUG 30 2015

.UPDATE...
ISSUED AT 455 PM MDT SUN AUG 30 2015

MAY A FEW MINOR ADJUSTMENTS TO THE FORECAST SPREADING CHANCES OF
SHOWERS AND THUNDERSTORMS SLIGHTLY FARTHER EAST INTO THIS EVENING.
ALSO REMOVED THE MENTION OF THUNDERSTORMS AFTER MIDNIGHT.

&&

.SHORT TERM...(THIS EVENING THROUGH TUESDAY NIGHT)

ISSUED AT 300 PM MDT SUN AUG 30 2015

SCATTERED LIGHT SHOWERS AND ISOLATED THUNDERSTORMS WILL
MOVE ACROSS SOUTHEAST WYOMING THIS AFTERNOON AND EVENING. SOME OF
THIS ACTIVITY MAY REACH THE NEBRASKA PANHANDLE. 40 TO 50 SPREADS
BETWEEN TEMPERATURES AND DEWPOINTS WILL MAKE IT TOUGH FOR MOISTURE
TO REACH THE GROUND SUCH THAT MEASURABLE RAIN WILL BE MINIMAL
WHERE IT DOES REACH THE SURFACE. THE LARGE SPREADS BETWEEN
TEMPERATURE AND DEW POINTS WILL PRODUCE THE POTENTIAL FOR
RELATIVELY STRONG DOWN DRAFTS CAPABLE OF PRODUCING WIND GUSTS OF
50 TO 60 MPH...IF NOT GREATER. COW CREEK RAWS ALREADY MEASURED A
GUST OF 54 MPH AT 243 PM. COOLING ALOFT...THE REAR ENTRANCE OF AN
UPPER LEVEL JET...AND MOIST MID FLOW MAY KEEP SOME SHOWER
ACTIVITY LINGERING INTO THE OVERNIGHT HOURS BUT STRONG WIND GUST
POTENTIAL WILL SUBSIDE.

MONDAY WILL SEE A BREAK IN THE VERY WARM TEMPERATURES WITH HIGHS
TYPICALLY IN THE 80S ACROSS THE FORECAST AREA. MID LEVEL MOISTURE
IS PROGGED TO BE IN PLACE ACROSS SOUTHERN PORTIONS OF THE FORECAST
AREA WHICH SHOULD YIELD A FEW MORE AFTERNOON AND EVENING SHOWERS
AND THUNDERSTORMS. AGAIN SEVERE THUNDERSTORMS ARE NOT A CONCERN
BUT A FEW STRONGER WIND GUSTS MAY BE POSSIBLE.

WARMER TEMPERATURES RETURN TUESDAY AS THE RIDGE REBOUNDS ACROSS
THE NORTHERN ROCKIES. HIGH TEMPERATURES TO WARM INTO THE 90S
ACROSS THE PLAINS AND 80S FARTHER WEST. LESSER CHANCES FOR
PRECIPITATION TUESDAY BUT MAY SEE A COUPLE SHOWERS DEVELOP OFF THE
HIGHER TERRAIN.

.LONG TERM...(WEDNESDAY THROUGH SUNDAY)
ISSUED AT 300 PM MDT SUN AUG 30 2015

THERE WILL CONTINUE TO BE SOUTHWESTERLY FLOW ALOFT THROUGHOUT THE
MAJORITY OF THE WEEK. A DRY AIRMASS ALOFT ON WEDNESDAY COULD
BRING CONCERNS FOR FIRE WEATHER WITH RH VALUES DOWN INTO THE MID
TO LOWER TEENS FOR CONVERSE AND NIOBRARA COUNTIES. TEMPERATURES
WILL REMAIN WARM OVER THE COURSE OF THE WEEK WITH POPS BEING LOW.
A FEW ISOLATED THUNDERSTORMS MAY BE SEEN OVER THE SIERRA MADRES
AND SNOWY RANGES ON WEDNESDAY. THURSDAY AND FRIDAY ARE EXPECTED TO
CONTINUE THIS HOT/DRY TREND. THIS PATTERN WILL CHANGE OVER THE
WEEKEND WHEN A UPPER LEVEL TROUGH IS PROJECTED TO MOVE EASTWARD
FROM THE PACIFIC NORTHWEST. A WEAK COLD FRONT PASSAGE ON SATURDAY
WILL BRING SOME SCATTERED SHOWERS AND THUNDERSTORMS...MAINLY
AFFECTING EAST OF THE LARAMIE RANGE INTO THE NEBRASKA PANHANDLE.
THE PASSAGE OF AN UPPER LEVEL TROUGH ON SUNDAY WILL BRING
TEMPERATURES AS WELL AS A CONTINUED CHANCE OF THUNDERSTORMS FOR
THE NEBRASKA PANHANDLE.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY AFTERNOON)
ISSUED AT 459 PM MDT SUN AUG 30 2015

VFR EXPECTED OVER ALL TERMINALS THROUGH THE PERIOD WITH MID LEVEL
CLOUDS SPREADING ACROSS THE AREA. ISOLATED SHOWERS AND TSTMS TONIGHT
WITH BRIEF GUSTY WINDS POSSIBLE AROUND THEM.

&&

.FIRE WEATHER...
ISSUED AT 157 PM MDT SUN AUG 30 2015

MAINLY DRY AND WARM THROUGH THIS WEEK ALTHOUGH THERE WILL
BE SOME CHANCES FOR WETTING RAINS. A FRONTAL BOUNDARY WILL
BRING SCATTERED SHOWERS AND A FEW THUNDERSTORMS TO THE AREA
INTO THIS EVENING. WIND GUSTS TO AROUND 55 MPH WILL OCCUR
WITH SOME SHOWERS AND THUNDERSTORMS INTO THIS EVENING.

COOLER TEMPERATURES MONDAY WILL SUPPRESS CRITICAL FIRE
WEATHER POTENTIAL BUT LATER INTO THE WEEK TEMPERATURES WILL
BE UNSEASONABLY WARM WITH HUMIDITIES DROPPING INTO THE 10
TO 15 PERCENT RANGE ACROSS SOUTHEAST WYOMING. WINDS WILL
BE GUSTY SEVERAL AFTERNOONS DURING THE WEEK SUCH THAT
CRITICAL FIRE THRESHOLDS MAY BE REACHED.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.

NE...NONE.

&&

$$

UPDATE...SML
SHORT TERM...SML
LONG TERM...GCC
AVIATION...RE
FIRE WEATHER...SML



000
FXUS65 KCYS 302319
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
459 PM MDT SUN AUG 30 2015

.UPDATE...
ISSUED AT 455 PM MDT SUN AUG 30 2015

MAY A FEW MINOR ADJUSTMENTS TO THE FORECAST SPREADING CHANCES OF
SHOWERS AND THUNDERSTORMS SLIGHTLY FARTHER EAST INTO THIS EVENING.
ALSO REMOVED THE MENTION OF THUNDERSTORMS AFTER MIDNIGHT.

&&

.SHORT TERM...(THIS EVENING THROUGH TUESDAY NIGHT)

ISSUED AT 300 PM MDT SUN AUG 30 2015

SCATTERED LIGHT SHOWERS AND ISOLATED THUNDERSTORMS WILL
MOVE ACROSS SOUTHEAST WYOMING THIS AFTERNOON AND EVENING. SOME OF
THIS ACTIVITY MAY REACH THE NEBRASKA PANHANDLE. 40 TO 50 SPREADS
BETWEEN TEMPERATURES AND DEWPOINTS WILL MAKE IT TOUGH FOR MOISTURE
TO REACH THE GROUND SUCH THAT MEASURABLE RAIN WILL BE MINIMAL
WHERE IT DOES REACH THE SURFACE. THE LARGE SPREADS BETWEEN
TEMPERATURE AND DEW POINTS WILL PRODUCE THE POTENTIAL FOR
RELATIVELY STRONG DOWN DRAFTS CAPABLE OF PRODUCING WIND GUSTS OF
50 TO 60 MPH...IF NOT GREATER. COW CREEK RAWS ALREADY MEASURED A
GUST OF 54 MPH AT 243 PM. COOLING ALOFT...THE REAR ENTRANCE OF AN
UPPER LEVEL JET...AND MOIST MID FLOW MAY KEEP SOME SHOWER
ACTIVITY LINGERING INTO THE OVERNIGHT HOURS BUT STRONG WIND GUST
POTENTIAL WILL SUBSIDE.

MONDAY WILL SEE A BREAK IN THE VERY WARM TEMPERATURES WITH HIGHS
TYPICALLY IN THE 80S ACROSS THE FORECAST AREA. MID LEVEL MOISTURE
IS PROGGED TO BE IN PLACE ACROSS SOUTHERN PORTIONS OF THE FORECAST
AREA WHICH SHOULD YIELD A FEW MORE AFTERNOON AND EVENING SHOWERS
AND THUNDERSTORMS. AGAIN SEVERE THUNDERSTORMS ARE NOT A CONCERN
BUT A FEW STRONGER WIND GUSTS MAY BE POSSIBLE.

WARMER TEMPERATURES RETURN TUESDAY AS THE RIDGE REBOUNDS ACROSS
THE NORTHERN ROCKIES. HIGH TEMPERATURES TO WARM INTO THE 90S
ACROSS THE PLAINS AND 80S FARTHER WEST. LESSER CHANCES FOR
PRECIPITATION TUESDAY BUT MAY SEE A COUPLE SHOWERS DEVELOP OFF THE
HIGHER TERRAIN.

.LONG TERM...(WEDNESDAY THROUGH SUNDAY)
ISSUED AT 300 PM MDT SUN AUG 30 2015

THERE WILL CONTINUE TO BE SOUTHWESTERLY FLOW ALOFT THROUGHOUT THE
MAJORITY OF THE WEEK. A DRY AIRMASS ALOFT ON WEDNESDAY COULD
BRING CONCERNS FOR FIRE WEATHER WITH RH VALUES DOWN INTO THE MID
TO LOWER TEENS FOR CONVERSE AND NIOBRARA COUNTIES. TEMPERATURES
WILL REMAIN WARM OVER THE COURSE OF THE WEEK WITH POPS BEING LOW.
A FEW ISOLATED THUNDERSTORMS MAY BE SEEN OVER THE SIERRA MADRES
AND SNOWY RANGES ON WEDNESDAY. THURSDAY AND FRIDAY ARE EXPECTED TO
CONTINUE THIS HOT/DRY TREND. THIS PATTERN WILL CHANGE OVER THE
WEEKEND WHEN A UPPER LEVEL TROUGH IS PROJECTED TO MOVE EASTWARD
FROM THE PACIFIC NORTHWEST. A WEAK COLD FRONT PASSAGE ON SATURDAY
WILL BRING SOME SCATTERED SHOWERS AND THUNDERSTORMS...MAINLY
AFFECTING EAST OF THE LARAMIE RANGE INTO THE NEBRASKA PANHANDLE.
THE PASSAGE OF AN UPPER LEVEL TROUGH ON SUNDAY WILL BRING
TEMPERATURES AS WELL AS A CONTINUED CHANCE OF THUNDERSTORMS FOR
THE NEBRASKA PANHANDLE.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY AFTERNOON)
ISSUED AT 459 PM MDT SUN AUG 30 2015

VFR EXPECTED OVER ALL TERMINALS THROUGH THE PERIOD WITH MID LEVEL
CLOUDS SPREADING ACROSS THE AREA. ISOLATED SHOWERS AND TSTMS TONIGHT
WITH BRIEF GUSTY WINDS POSSIBLE AROUND THEM.

&&

.FIRE WEATHER...
ISSUED AT 157 PM MDT SUN AUG 30 2015

MAINLY DRY AND WARM THROUGH THIS WEEK ALTHOUGH THERE WILL
BE SOME CHANCES FOR WETTING RAINS. A FRONTAL BOUNDARY WILL
BRING SCATTERED SHOWERS AND A FEW THUNDERSTORMS TO THE AREA
INTO THIS EVENING. WIND GUSTS TO AROUND 55 MPH WILL OCCUR
WITH SOME SHOWERS AND THUNDERSTORMS INTO THIS EVENING.

COOLER TEMPERATURES MONDAY WILL SUPPRESS CRITICAL FIRE
WEATHER POTENTIAL BUT LATER INTO THE WEEK TEMPERATURES WILL
BE UNSEASONABLY WARM WITH HUMIDITIES DROPPING INTO THE 10
TO 15 PERCENT RANGE ACROSS SOUTHEAST WYOMING. WINDS WILL
BE GUSTY SEVERAL AFTERNOONS DURING THE WEEK SUCH THAT
CRITICAL FIRE THRESHOLDS MAY BE REACHED.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.

NE...NONE.

&&

$$

UPDATE...SML
SHORT TERM...SML
LONG TERM...GCC
AVIATION...RE
FIRE WEATHER...SML



000
FXUS65 KCYS 302319
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
459 PM MDT SUN AUG 30 2015

.UPDATE...
ISSUED AT 455 PM MDT SUN AUG 30 2015

MAY A FEW MINOR ADJUSTMENTS TO THE FORECAST SPREADING CHANCES OF
SHOWERS AND THUNDERSTORMS SLIGHTLY FARTHER EAST INTO THIS EVENING.
ALSO REMOVED THE MENTION OF THUNDERSTORMS AFTER MIDNIGHT.

&&

.SHORT TERM...(THIS EVENING THROUGH TUESDAY NIGHT)

ISSUED AT 300 PM MDT SUN AUG 30 2015

SCATTERED LIGHT SHOWERS AND ISOLATED THUNDERSTORMS WILL
MOVE ACROSS SOUTHEAST WYOMING THIS AFTERNOON AND EVENING. SOME OF
THIS ACTIVITY MAY REACH THE NEBRASKA PANHANDLE. 40 TO 50 SPREADS
BETWEEN TEMPERATURES AND DEWPOINTS WILL MAKE IT TOUGH FOR MOISTURE
TO REACH THE GROUND SUCH THAT MEASURABLE RAIN WILL BE MINIMAL
WHERE IT DOES REACH THE SURFACE. THE LARGE SPREADS BETWEEN
TEMPERATURE AND DEW POINTS WILL PRODUCE THE POTENTIAL FOR
RELATIVELY STRONG DOWN DRAFTS CAPABLE OF PRODUCING WIND GUSTS OF
50 TO 60 MPH...IF NOT GREATER. COW CREEK RAWS ALREADY MEASURED A
GUST OF 54 MPH AT 243 PM. COOLING ALOFT...THE REAR ENTRANCE OF AN
UPPER LEVEL JET...AND MOIST MID FLOW MAY KEEP SOME SHOWER
ACTIVITY LINGERING INTO THE OVERNIGHT HOURS BUT STRONG WIND GUST
POTENTIAL WILL SUBSIDE.

MONDAY WILL SEE A BREAK IN THE VERY WARM TEMPERATURES WITH HIGHS
TYPICALLY IN THE 80S ACROSS THE FORECAST AREA. MID LEVEL MOISTURE
IS PROGGED TO BE IN PLACE ACROSS SOUTHERN PORTIONS OF THE FORECAST
AREA WHICH SHOULD YIELD A FEW MORE AFTERNOON AND EVENING SHOWERS
AND THUNDERSTORMS. AGAIN SEVERE THUNDERSTORMS ARE NOT A CONCERN
BUT A FEW STRONGER WIND GUSTS MAY BE POSSIBLE.

WARMER TEMPERATURES RETURN TUESDAY AS THE RIDGE REBOUNDS ACROSS
THE NORTHERN ROCKIES. HIGH TEMPERATURES TO WARM INTO THE 90S
ACROSS THE PLAINS AND 80S FARTHER WEST. LESSER CHANCES FOR
PRECIPITATION TUESDAY BUT MAY SEE A COUPLE SHOWERS DEVELOP OFF THE
HIGHER TERRAIN.

.LONG TERM...(WEDNESDAY THROUGH SUNDAY)
ISSUED AT 300 PM MDT SUN AUG 30 2015

THERE WILL CONTINUE TO BE SOUTHWESTERLY FLOW ALOFT THROUGHOUT THE
MAJORITY OF THE WEEK. A DRY AIRMASS ALOFT ON WEDNESDAY COULD
BRING CONCERNS FOR FIRE WEATHER WITH RH VALUES DOWN INTO THE MID
TO LOWER TEENS FOR CONVERSE AND NIOBRARA COUNTIES. TEMPERATURES
WILL REMAIN WARM OVER THE COURSE OF THE WEEK WITH POPS BEING LOW.
A FEW ISOLATED THUNDERSTORMS MAY BE SEEN OVER THE SIERRA MADRES
AND SNOWY RANGES ON WEDNESDAY. THURSDAY AND FRIDAY ARE EXPECTED TO
CONTINUE THIS HOT/DRY TREND. THIS PATTERN WILL CHANGE OVER THE
WEEKEND WHEN A UPPER LEVEL TROUGH IS PROJECTED TO MOVE EASTWARD
FROM THE PACIFIC NORTHWEST. A WEAK COLD FRONT PASSAGE ON SATURDAY
WILL BRING SOME SCATTERED SHOWERS AND THUNDERSTORMS...MAINLY
AFFECTING EAST OF THE LARAMIE RANGE INTO THE NEBRASKA PANHANDLE.
THE PASSAGE OF AN UPPER LEVEL TROUGH ON SUNDAY WILL BRING
TEMPERATURES AS WELL AS A CONTINUED CHANCE OF THUNDERSTORMS FOR
THE NEBRASKA PANHANDLE.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY AFTERNOON)
ISSUED AT 459 PM MDT SUN AUG 30 2015

VFR EXPECTED OVER ALL TERMINALS THROUGH THE PERIOD WITH MID LEVEL
CLOUDS SPREADING ACROSS THE AREA. ISOLATED SHOWERS AND TSTMS TONIGHT
WITH BRIEF GUSTY WINDS POSSIBLE AROUND THEM.

&&

.FIRE WEATHER...
ISSUED AT 157 PM MDT SUN AUG 30 2015

MAINLY DRY AND WARM THROUGH THIS WEEK ALTHOUGH THERE WILL
BE SOME CHANCES FOR WETTING RAINS. A FRONTAL BOUNDARY WILL
BRING SCATTERED SHOWERS AND A FEW THUNDERSTORMS TO THE AREA
INTO THIS EVENING. WIND GUSTS TO AROUND 55 MPH WILL OCCUR
WITH SOME SHOWERS AND THUNDERSTORMS INTO THIS EVENING.

COOLER TEMPERATURES MONDAY WILL SUPPRESS CRITICAL FIRE
WEATHER POTENTIAL BUT LATER INTO THE WEEK TEMPERATURES WILL
BE UNSEASONABLY WARM WITH HUMIDITIES DROPPING INTO THE 10
TO 15 PERCENT RANGE ACROSS SOUTHEAST WYOMING. WINDS WILL
BE GUSTY SEVERAL AFTERNOONS DURING THE WEEK SUCH THAT
CRITICAL FIRE THRESHOLDS MAY BE REACHED.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.

NE...NONE.

&&

$$

UPDATE...SML
SHORT TERM...SML
LONG TERM...GCC
AVIATION...RE
FIRE WEATHER...SML



000
FXUS65 KCYS 302319
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
459 PM MDT SUN AUG 30 2015

.UPDATE...
ISSUED AT 455 PM MDT SUN AUG 30 2015

MAY A FEW MINOR ADJUSTMENTS TO THE FORECAST SPREADING CHANCES OF
SHOWERS AND THUNDERSTORMS SLIGHTLY FARTHER EAST INTO THIS EVENING.
ALSO REMOVED THE MENTION OF THUNDERSTORMS AFTER MIDNIGHT.

&&

.SHORT TERM...(THIS EVENING THROUGH TUESDAY NIGHT)

ISSUED AT 300 PM MDT SUN AUG 30 2015

SCATTERED LIGHT SHOWERS AND ISOLATED THUNDERSTORMS WILL
MOVE ACROSS SOUTHEAST WYOMING THIS AFTERNOON AND EVENING. SOME OF
THIS ACTIVITY MAY REACH THE NEBRASKA PANHANDLE. 40 TO 50 SPREADS
BETWEEN TEMPERATURES AND DEWPOINTS WILL MAKE IT TOUGH FOR MOISTURE
TO REACH THE GROUND SUCH THAT MEASURABLE RAIN WILL BE MINIMAL
WHERE IT DOES REACH THE SURFACE. THE LARGE SPREADS BETWEEN
TEMPERATURE AND DEW POINTS WILL PRODUCE THE POTENTIAL FOR
RELATIVELY STRONG DOWN DRAFTS CAPABLE OF PRODUCING WIND GUSTS OF
50 TO 60 MPH...IF NOT GREATER. COW CREEK RAWS ALREADY MEASURED A
GUST OF 54 MPH AT 243 PM. COOLING ALOFT...THE REAR ENTRANCE OF AN
UPPER LEVEL JET...AND MOIST MID FLOW MAY KEEP SOME SHOWER
ACTIVITY LINGERING INTO THE OVERNIGHT HOURS BUT STRONG WIND GUST
POTENTIAL WILL SUBSIDE.

MONDAY WILL SEE A BREAK IN THE VERY WARM TEMPERATURES WITH HIGHS
TYPICALLY IN THE 80S ACROSS THE FORECAST AREA. MID LEVEL MOISTURE
IS PROGGED TO BE IN PLACE ACROSS SOUTHERN PORTIONS OF THE FORECAST
AREA WHICH SHOULD YIELD A FEW MORE AFTERNOON AND EVENING SHOWERS
AND THUNDERSTORMS. AGAIN SEVERE THUNDERSTORMS ARE NOT A CONCERN
BUT A FEW STRONGER WIND GUSTS MAY BE POSSIBLE.

WARMER TEMPERATURES RETURN TUESDAY AS THE RIDGE REBOUNDS ACROSS
THE NORTHERN ROCKIES. HIGH TEMPERATURES TO WARM INTO THE 90S
ACROSS THE PLAINS AND 80S FARTHER WEST. LESSER CHANCES FOR
PRECIPITATION TUESDAY BUT MAY SEE A COUPLE SHOWERS DEVELOP OFF THE
HIGHER TERRAIN.

.LONG TERM...(WEDNESDAY THROUGH SUNDAY)
ISSUED AT 300 PM MDT SUN AUG 30 2015

THERE WILL CONTINUE TO BE SOUTHWESTERLY FLOW ALOFT THROUGHOUT THE
MAJORITY OF THE WEEK. A DRY AIRMASS ALOFT ON WEDNESDAY COULD
BRING CONCERNS FOR FIRE WEATHER WITH RH VALUES DOWN INTO THE MID
TO LOWER TEENS FOR CONVERSE AND NIOBRARA COUNTIES. TEMPERATURES
WILL REMAIN WARM OVER THE COURSE OF THE WEEK WITH POPS BEING LOW.
A FEW ISOLATED THUNDERSTORMS MAY BE SEEN OVER THE SIERRA MADRES
AND SNOWY RANGES ON WEDNESDAY. THURSDAY AND FRIDAY ARE EXPECTED TO
CONTINUE THIS HOT/DRY TREND. THIS PATTERN WILL CHANGE OVER THE
WEEKEND WHEN A UPPER LEVEL TROUGH IS PROJECTED TO MOVE EASTWARD
FROM THE PACIFIC NORTHWEST. A WEAK COLD FRONT PASSAGE ON SATURDAY
WILL BRING SOME SCATTERED SHOWERS AND THUNDERSTORMS...MAINLY
AFFECTING EAST OF THE LARAMIE RANGE INTO THE NEBRASKA PANHANDLE.
THE PASSAGE OF AN UPPER LEVEL TROUGH ON SUNDAY WILL BRING
TEMPERATURES AS WELL AS A CONTINUED CHANCE OF THUNDERSTORMS FOR
THE NEBRASKA PANHANDLE.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY AFTERNOON)
ISSUED AT 459 PM MDT SUN AUG 30 2015

VFR EXPECTED OVER ALL TERMINALS THROUGH THE PERIOD WITH MID LEVEL
CLOUDS SPREADING ACROSS THE AREA. ISOLATED SHOWERS AND TSTMS TONIGHT
WITH BRIEF GUSTY WINDS POSSIBLE AROUND THEM.

&&

.FIRE WEATHER...
ISSUED AT 157 PM MDT SUN AUG 30 2015

MAINLY DRY AND WARM THROUGH THIS WEEK ALTHOUGH THERE WILL
BE SOME CHANCES FOR WETTING RAINS. A FRONTAL BOUNDARY WILL
BRING SCATTERED SHOWERS AND A FEW THUNDERSTORMS TO THE AREA
INTO THIS EVENING. WIND GUSTS TO AROUND 55 MPH WILL OCCUR
WITH SOME SHOWERS AND THUNDERSTORMS INTO THIS EVENING.

COOLER TEMPERATURES MONDAY WILL SUPPRESS CRITICAL FIRE
WEATHER POTENTIAL BUT LATER INTO THE WEEK TEMPERATURES WILL
BE UNSEASONABLY WARM WITH HUMIDITIES DROPPING INTO THE 10
TO 15 PERCENT RANGE ACROSS SOUTHEAST WYOMING. WINDS WILL
BE GUSTY SEVERAL AFTERNOONS DURING THE WEEK SUCH THAT
CRITICAL FIRE THRESHOLDS MAY BE REACHED.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.

NE...NONE.

&&

$$

UPDATE...SML
SHORT TERM...SML
LONG TERM...GCC
AVIATION...RE
FIRE WEATHER...SML



000
FXUS65 KCYS 302259
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
459 PM MDT SUN AUG 30 2015

.UPDATE...
ISSUED AT 455 PM MDT SUN AUG 30 2015

MAY A FEW MINOR ADJUSTMENTS TO THE FORECAST SPREADING CHANCES OF
SHOWERS AND THUNDERSTORMS SLIGHTLY FARTHER EAST INTO THIS EVENING.
ALSO REMOVED THE MENTION OF THUNDERSTORMS AFTER MIDNIGHT.

&&

.SHORT TERM...(THIS EVENING THROUGH TUESDAY NIGHT)

ISSUED AT 300 PM MDT SUN AUG 30 2015

SCATTERED LIGHT SHOWERS AND ISOLATED THUNDERSTORMS WILL
MOVE ACROSS SOUTHEAST WYOMING THIS AFTERNOON AND EVENING. SOME OF
THIS ACTIVITY MAY REACH THE NEBRASKA PANHANDLE. 40 TO 50 SPREADS
BETWEEN TEMPERATURES AND DEWPOINTS WILL MAKE IT TOUGH FOR MOISTURE
TO REACH THE GROUND SUCH THAT MEASURABLE RAIN WILL BE MINIMAL
WHERE IT DOES REACH THE SURFACE. THE LARGE SPREADS BETWEEN
TEMPERATURE AND DEW POINTS WILL PRODUCE THE POTENTIAL FOR
RELATIVELY STRONG DOWN DRAFTS CAPABLE OF PRODUCING WIND GUSTS OF
50 TO 60 MPH...IF NOT GREATER. COW CREEK RAWS ALREADY MEASURED A
GUST OF 54 MPH AT 243 PM. COOLING ALOFT...THE REAR ENTRANCE OF AN
UPPER LEVEL JET...AND MOIST MID FLOW MAY KEEP SOME SHOWER
ACTIVITY LINGERING INTO THE OVERNIGHT HOURS BUT STRONG WIND GUST
POTENTIAL WILL SUBSIDE.

MONDAY WILL SEE A BREAK IN THE VERY WARM TEMPERATURES WITH HIGHS
TYPICALLY IN THE 80S ACROSS THE FORECAST AREA. MID LEVEL MOISTURE
IS PROGGED TO BE IN PLACE ACROSS SOUTHERN PORTIONS OF THE FORECAST
AREA WHICH SHOULD YIELD A FEW MORE AFTERNOON AND EVENING SHOWERS
AND THUNDERSTORMS. AGAIN SEVERE THUNDERSTORMS ARE NOT A CONCERN
BUT A FEW STRONGER WIND GUSTS MAY BE POSSIBLE.

WARMER TEMPERATURES RETURN TUESDAY AS THE RIDGE REBOUNDS ACROSS
THE NORTHERN ROCKIES. HIGH TEMPERATURES TO WARM INTO THE 90S
ACROSS THE PLAINS AND 80S FARTHER WEST. LESSER CHANCES FOR
PRECIPITATION TUESDAY BUT MAY SEE A COUPLE SHOWERS DEVELOP OFF THE
HIGHER TERRAIN.

.LONG TERM...(WEDNESDAY THROUGH SUNDAY)
ISSUED AT 300 PM MDT SUN AUG 30 2015

THERE WILL CONTINUE TO BE SOUTHWESTERLY FLOW ALOFT THROUGHOUT THE
MAJORITY OF THE WEEK. A DRY AIRMASS ALOFT ON WEDNESDAY COULD
BRING CONCERNS FOR FIRE WEATHER WITH RH VALUES DOWN INTO THE MID
TO LOWER TEENS FOR CONVERSE AND NIOBRARA COUNTIES. TEMPERATURES
WILL REMAIN WARM OVER THE COURSE OF THE WEEK WITH POPS BEING LOW.
A FEW ISOLATED THUNDERSTORMS MAY BE SEEN OVER THE SIERRA MADRES
AND SNOWY RANGES ON WEDNESDAY. THURSDAY AND FRIDAY ARE EXPECTED TO
CONTINUE THIS HOT/DRY TREND. THIS PATTERN WILL CHANGE OVER THE
WEEKEND WHEN A UPPER LEVEL TROUGH IS PROJECTED TO MOVE EASTWARD
FROM THE PACIFIC NORTHWEST. A WEAK COLD FRONT PASSAGE ON SATURDAY
WILL BRING SOME SCATTERED SHOWERS AND THUNDERSTORMS...MAINLY
AFFECTING EAST OF THE LARAMIE RANGE INTO THE NEBRASKA PANHANDLE.
THE PASSAGE OF AN UPPER LEVEL TROUGH ON SUNDAY WILL BRING
TEMPERATURES AS WELL AS A CONTINUED CHANCE OF THUNDERSTORMS FOR
THE NEBRASKA PANHANDLE.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1120 AM MDT SUN AUG 30 2015

SCATTERED THUNDERSTORMS THIS AFTERNOON...FOR RAWLINS AND LARAMIE
AS AN UPPER LEVEL DISTURBANCE MOVES ACROSS THE FORECAST AREA.
CHEYENNE COULD SEE SOME ISOLATED SHOWERS LATER INTO THE NIGHT.
BRIEF MVFR CONDITIONS CAN BE SEEN WITH A PASSING THUNDERSTORM.
OTHERWISE EXPECT VFR CONDITIONS THROUGHOUT THE DAY. WINDS ARE
EXPECTED TO PICK UP THROUGHOUT THE AFTERNOON HOURS FOR THE
NEBRASKA PANHANDLE. OVERNIGHT WINDS WILL CONTINUE TO BE GUSTY FOR
CHADRON WITH THE DEVELOPMENT OF A LLVL JET.


&&

.FIRE WEATHER...
ISSUED AT 157 PM MDT SUN AUG 30 2015

MAINLY DRY AND WARM THROUGH THIS WEEK ALTHOUGH THERE WILL
BE SOME CHANCES FOR WETTING RAINS. A FRONTAL BOUNDARY WILL
BRING SCATTERED SHOWERS AND A FEW THUNDERSTORMS TO THE AREA
INTO THIS EVENING. WIND GUSTS TO AROUND 55 MPH WILL OCCUR
WITH SOME SHOWERS AND THUNDERSTORMS INTO THIS EVENING.

COOLER TEMPERATURES MONDAY WILL SUPPRESS CRITICAL FIRE
WEATHER POTENTIAL BUT LATER INTO THE WEEK TEMPERATURES WILL
BE UNSEASONABLY WARM WITH HUMIDITIES DROPPING INTO THE 10
TO 15 PERCENT RANGE ACROSS SOUTHEAST WYOMING. WINDS WILL
BE GUSTY SEVERAL AFTERNOONS DURING THE WEEK SUCH THAT
CRITICAL FIRE THRESHOLDS MAY BE REACHED.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.

NE...NONE.

&&

$$

UPDATE...SML
SHORT TERM...SML
LONG TERM...GCC
AVIATION...GCC
FIRE WEATHER...SML




000
FXUS65 KCYS 302152
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
352 PM MDT SUN AUG 30 2015

.SHORT TERM...(THIS EVENING THROUGH TUESDAY NIGHT)

ISSUED AT 300 PM MDT SUN AUG 30 2015

SCATTERED LIGHT SHOWERS AND ISOLATED THUNDERSTORMS WILL
MOVE ACROSS SOUTHEAST WYOMING THIS AFTERNOON AND EVENING. SOME OF
THIS ACTIVITY MAY REACH THE NEBRASKA PANHANDLE. 40 TO 50 SPREADS
BETWEEN TEMPERATURES AND DEWPOINTS WILL MAKE IT TOUGH FOR MOISTURE
TO REACH THE GROUND SUCH THAT MEASURABLE RAIN WILL BE MINIMAL
WHERE IT DOES REACH THE SURFACE. THE LARGE SPREADS BETWEEN
TEMPERATURE AND DEW POINTS WILL PRODUCE THE POTENTIAL FOR
RELATIVELY STRONG DOWN DRAFTS CAPABLE OF PRODUCING WIND GUSTS OF
50 TO 60 MPH...IF NOT GREATER. COW CREEK RAWS ALREADY MEASURED A
GUST OF 54 MPH AT 243 PM. COOLING ALOFT...THE REAR ENTRANCE OF AN
UPPER LEVEL JET...AND MOIST MID FLOW MAY KEEP SOME SHOWER
ACTIVITY LINGERING INTO THE OVERNIGHT HOURS BUT STRONG WIND GUST
POTENTIAL WILL SUBSIDE.

MONDAY WILL SEE A BREAK IN THE VERY WARM TEMPERATURES WITH HIGHS
TYPICALLY IN THE 80S ACROSS THE FORECAST AREA. MID LEVEL MOISTURE
IS PROGGED TO BE IN PLACE ACROSS SOUTHERN PORTIONS OF THE FORECAST
AREA WHICH SHOULD YIELD A FEW MORE AFTERNOON AND EVENING SHOWERS
AND THUNDERSTORMS. AGAIN SEVERE THUNDERSTORMS ARE NOT A CONCERN
BUT A FEW STRONGER WIND GUSTS MAY BE POSSIBLE.

WARMER TEMPERATURES RETURN TUESDAY AS THE RIDGE REBOUNDS ACROSS
THE NORTHERN ROCKIES. HIGH TEMPERATURES TO WARM INTO THE 90S
ACROSS THE PLAINS AND 80S FARTHER WEST. LESSER CHANCES FOR
PRECIPITATION TUESDAY BUT MAY SEE A COUPLE SHOWERS DEVELOP OFF THE
HIGHER TERRAIN.


.LONG TERM...(WEDNESDAY THROUGH SUNDAY)
ISSUED AT 300 PM MDT SUN AUG 30 2015

THERE WILL CONTINUE TO BE SOUTHWESTERLY FLOW ALOFT THROUGHOUT THE
MAJORITY OF THE WEEK. A DRY AIRMASS ALOFT ON WEDNESDAY COULD
BRING CONCERNS FOR FIRE WEATHER WITH RH VALUES DOWN INTO THE MID
TO LOWER TEENS FOR CONVERSE AND NIOBRARA COUNTIES. TEMPERATURES
WILL REMAIN WARM OVER THE COURSE OF THE WEEK WITH POPS BEING LOW.
A FEW ISOLATED THUNDERSTORMS MAY BE SEEN OVER THE SIERRA MADRES
AND SNOWY RANGES ON WEDNESDAY. THURSDAY AND FRIDAY ARE EXPECTED TO
CONTINUE THIS HOT/DRY TREND. THIS PATTERN WILL CHANGE OVER THE
WEEKEND WHEN A UPPER LEVEL TROUGH IS PROJECTED TO MOVE EASTWARD
FROM THE PACIFIC NORTHWEST. A WEAK COLD FRONT PASSAGE ON SATURDAY
WILL BRING SOME SCATTERED SHOWERS AND THUNDERSTORMS...MAINLY
AFFECTING EAST OF THE LARAMIE RANGE INTO THE NEBRASKA PANHANDLE.
THE PASSAGE OF AN UPPER LEVEL TROUGH ON SUNDAY WILL BRING
TEMPERATURES AS WELL AS A CONTINUED CHANCE OF THUNDERSTORMS FOR
THE NEBRASKA PANHANDLE.


&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1120 AM MDT SUN AUG 30 2015

SCATTERED THUNDERSTORMS THIS AFTERNOON...FOR RAWLINS AND LARAMIE
AS AN UPPER LEVEL DISTURBANCE MOVES ACROSS THE FORECAST AREA.
CHEYENNE COULD SEE SOME ISOLATED SHOWERS LATER INTO THE NIGHT.
BRIEF MVFR CONDITIONS CAN BE SEEN WITH A PASSING THUNDERSTORM.
OTHERWISE EXPECT VFR CONDITIONS THROUGHOUT THE DAY. WINDS ARE
EXPECTED TO PICK UP THROUGHOUT THE AFTERNOON HOURS FOR THE
NEBRASKA PANHANDLE. OVERNIGHT WINDS WILL CONTINUE TO BE GUSTY FOR
CHADRON WITH THE DEVELOPMENT OF A LLVL JET.


&&

.FIRE WEATHER...
ISSUED AT 157 PM MDT SUN AUG 30 2015

MAINLY DRY AND WARM THROUGH THIS WEEK ALTHOUGH THERE WILL
BE SOME CHANCES FOR WETTING RAINS. A FRONTAL BOUNDARY WILL
BRING SCATTERED SHOWERS AND A FEW THUNDERSTORMS TO THE AREA
INTO THIS EVENING. WIND GUSTS TO AROUND 55 MPH WILL OCCUR
WITH SOME SHOWERS AND THUNDERSTORMS INTO THIS EVENING.

COOLER TEMPERATURES MONDAY WILL SUPPRESS CRITICAL FIRE
WEATHER POTENTIAL BUT LATER INTO THE WEEK TEMPERATURES WILL
BE UNSEASONABLY WARM WITH HUMIDITIES DROPPING INTO THE 10
TO 15 PERCENT RANGE ACROSS SOUTHEAST WYOMING. WINDS WILL
BE GUSTY SEVERAL AFTERNOONS DURING THE WEEK SUCH THAT
CRITICAL FIRE THRESHOLDS MAY BE REACHED.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...RED FLAG WARNING UNTIL 7 PM MDT THIS EVENING FOR WYZ301.

NE...NONE.

&&

$$

SHORT TERM...SML
LONG TERM...GCC
AVIATION...GCC
FIRE WEATHER...SML



000
FXUS65 KCYS 302152
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
352 PM MDT SUN AUG 30 2015

.SHORT TERM...(THIS EVENING THROUGH TUESDAY NIGHT)

ISSUED AT 300 PM MDT SUN AUG 30 2015

SCATTERED LIGHT SHOWERS AND ISOLATED THUNDERSTORMS WILL
MOVE ACROSS SOUTHEAST WYOMING THIS AFTERNOON AND EVENING. SOME OF
THIS ACTIVITY MAY REACH THE NEBRASKA PANHANDLE. 40 TO 50 SPREADS
BETWEEN TEMPERATURES AND DEWPOINTS WILL MAKE IT TOUGH FOR MOISTURE
TO REACH THE GROUND SUCH THAT MEASURABLE RAIN WILL BE MINIMAL
WHERE IT DOES REACH THE SURFACE. THE LARGE SPREADS BETWEEN
TEMPERATURE AND DEW POINTS WILL PRODUCE THE POTENTIAL FOR
RELATIVELY STRONG DOWN DRAFTS CAPABLE OF PRODUCING WIND GUSTS OF
50 TO 60 MPH...IF NOT GREATER. COW CREEK RAWS ALREADY MEASURED A
GUST OF 54 MPH AT 243 PM. COOLING ALOFT...THE REAR ENTRANCE OF AN
UPPER LEVEL JET...AND MOIST MID FLOW MAY KEEP SOME SHOWER
ACTIVITY LINGERING INTO THE OVERNIGHT HOURS BUT STRONG WIND GUST
POTENTIAL WILL SUBSIDE.

MONDAY WILL SEE A BREAK IN THE VERY WARM TEMPERATURES WITH HIGHS
TYPICALLY IN THE 80S ACROSS THE FORECAST AREA. MID LEVEL MOISTURE
IS PROGGED TO BE IN PLACE ACROSS SOUTHERN PORTIONS OF THE FORECAST
AREA WHICH SHOULD YIELD A FEW MORE AFTERNOON AND EVENING SHOWERS
AND THUNDERSTORMS. AGAIN SEVERE THUNDERSTORMS ARE NOT A CONCERN
BUT A FEW STRONGER WIND GUSTS MAY BE POSSIBLE.

WARMER TEMPERATURES RETURN TUESDAY AS THE RIDGE REBOUNDS ACROSS
THE NORTHERN ROCKIES. HIGH TEMPERATURES TO WARM INTO THE 90S
ACROSS THE PLAINS AND 80S FARTHER WEST. LESSER CHANCES FOR
PRECIPITATION TUESDAY BUT MAY SEE A COUPLE SHOWERS DEVELOP OFF THE
HIGHER TERRAIN.


.LONG TERM...(WEDNESDAY THROUGH SUNDAY)
ISSUED AT 300 PM MDT SUN AUG 30 2015

THERE WILL CONTINUE TO BE SOUTHWESTERLY FLOW ALOFT THROUGHOUT THE
MAJORITY OF THE WEEK. A DRY AIRMASS ALOFT ON WEDNESDAY COULD
BRING CONCERNS FOR FIRE WEATHER WITH RH VALUES DOWN INTO THE MID
TO LOWER TEENS FOR CONVERSE AND NIOBRARA COUNTIES. TEMPERATURES
WILL REMAIN WARM OVER THE COURSE OF THE WEEK WITH POPS BEING LOW.
A FEW ISOLATED THUNDERSTORMS MAY BE SEEN OVER THE SIERRA MADRES
AND SNOWY RANGES ON WEDNESDAY. THURSDAY AND FRIDAY ARE EXPECTED TO
CONTINUE THIS HOT/DRY TREND. THIS PATTERN WILL CHANGE OVER THE
WEEKEND WHEN A UPPER LEVEL TROUGH IS PROJECTED TO MOVE EASTWARD
FROM THE PACIFIC NORTHWEST. A WEAK COLD FRONT PASSAGE ON SATURDAY
WILL BRING SOME SCATTERED SHOWERS AND THUNDERSTORMS...MAINLY
AFFECTING EAST OF THE LARAMIE RANGE INTO THE NEBRASKA PANHANDLE.
THE PASSAGE OF AN UPPER LEVEL TROUGH ON SUNDAY WILL BRING
TEMPERATURES AS WELL AS A CONTINUED CHANCE OF THUNDERSTORMS FOR
THE NEBRASKA PANHANDLE.


&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1120 AM MDT SUN AUG 30 2015

SCATTERED THUNDERSTORMS THIS AFTERNOON...FOR RAWLINS AND LARAMIE
AS AN UPPER LEVEL DISTURBANCE MOVES ACROSS THE FORECAST AREA.
CHEYENNE COULD SEE SOME ISOLATED SHOWERS LATER INTO THE NIGHT.
BRIEF MVFR CONDITIONS CAN BE SEEN WITH A PASSING THUNDERSTORM.
OTHERWISE EXPECT VFR CONDITIONS THROUGHOUT THE DAY. WINDS ARE
EXPECTED TO PICK UP THROUGHOUT THE AFTERNOON HOURS FOR THE
NEBRASKA PANHANDLE. OVERNIGHT WINDS WILL CONTINUE TO BE GUSTY FOR
CHADRON WITH THE DEVELOPMENT OF A LLVL JET.


&&

.FIRE WEATHER...
ISSUED AT 157 PM MDT SUN AUG 30 2015

MAINLY DRY AND WARM THROUGH THIS WEEK ALTHOUGH THERE WILL
BE SOME CHANCES FOR WETTING RAINS. A FRONTAL BOUNDARY WILL
BRING SCATTERED SHOWERS AND A FEW THUNDERSTORMS TO THE AREA
INTO THIS EVENING. WIND GUSTS TO AROUND 55 MPH WILL OCCUR
WITH SOME SHOWERS AND THUNDERSTORMS INTO THIS EVENING.

COOLER TEMPERATURES MONDAY WILL SUPPRESS CRITICAL FIRE
WEATHER POTENTIAL BUT LATER INTO THE WEEK TEMPERATURES WILL
BE UNSEASONABLY WARM WITH HUMIDITIES DROPPING INTO THE 10
TO 15 PERCENT RANGE ACROSS SOUTHEAST WYOMING. WINDS WILL
BE GUSTY SEVERAL AFTERNOONS DURING THE WEEK SUCH THAT
CRITICAL FIRE THRESHOLDS MAY BE REACHED.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...RED FLAG WARNING UNTIL 7 PM MDT THIS EVENING FOR WYZ301.

NE...NONE.

&&

$$

SHORT TERM...SML
LONG TERM...GCC
AVIATION...GCC
FIRE WEATHER...SML




000
FXUS65 KCYS 302152
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
352 PM MDT SUN AUG 30 2015

.SHORT TERM...(THIS EVENING THROUGH TUESDAY NIGHT)

ISSUED AT 300 PM MDT SUN AUG 30 2015

SCATTERED LIGHT SHOWERS AND ISOLATED THUNDERSTORMS WILL
MOVE ACROSS SOUTHEAST WYOMING THIS AFTERNOON AND EVENING. SOME OF
THIS ACTIVITY MAY REACH THE NEBRASKA PANHANDLE. 40 TO 50 SPREADS
BETWEEN TEMPERATURES AND DEWPOINTS WILL MAKE IT TOUGH FOR MOISTURE
TO REACH THE GROUND SUCH THAT MEASURABLE RAIN WILL BE MINIMAL
WHERE IT DOES REACH THE SURFACE. THE LARGE SPREADS BETWEEN
TEMPERATURE AND DEW POINTS WILL PRODUCE THE POTENTIAL FOR
RELATIVELY STRONG DOWN DRAFTS CAPABLE OF PRODUCING WIND GUSTS OF
50 TO 60 MPH...IF NOT GREATER. COW CREEK RAWS ALREADY MEASURED A
GUST OF 54 MPH AT 243 PM. COOLING ALOFT...THE REAR ENTRANCE OF AN
UPPER LEVEL JET...AND MOIST MID FLOW MAY KEEP SOME SHOWER
ACTIVITY LINGERING INTO THE OVERNIGHT HOURS BUT STRONG WIND GUST
POTENTIAL WILL SUBSIDE.

MONDAY WILL SEE A BREAK IN THE VERY WARM TEMPERATURES WITH HIGHS
TYPICALLY IN THE 80S ACROSS THE FORECAST AREA. MID LEVEL MOISTURE
IS PROGGED TO BE IN PLACE ACROSS SOUTHERN PORTIONS OF THE FORECAST
AREA WHICH SHOULD YIELD A FEW MORE AFTERNOON AND EVENING SHOWERS
AND THUNDERSTORMS. AGAIN SEVERE THUNDERSTORMS ARE NOT A CONCERN
BUT A FEW STRONGER WIND GUSTS MAY BE POSSIBLE.

WARMER TEMPERATURES RETURN TUESDAY AS THE RIDGE REBOUNDS ACROSS
THE NORTHERN ROCKIES. HIGH TEMPERATURES TO WARM INTO THE 90S
ACROSS THE PLAINS AND 80S FARTHER WEST. LESSER CHANCES FOR
PRECIPITATION TUESDAY BUT MAY SEE A COUPLE SHOWERS DEVELOP OFF THE
HIGHER TERRAIN.


.LONG TERM...(WEDNESDAY THROUGH SUNDAY)
ISSUED AT 300 PM MDT SUN AUG 30 2015

THERE WILL CONTINUE TO BE SOUTHWESTERLY FLOW ALOFT THROUGHOUT THE
MAJORITY OF THE WEEK. A DRY AIRMASS ALOFT ON WEDNESDAY COULD
BRING CONCERNS FOR FIRE WEATHER WITH RH VALUES DOWN INTO THE MID
TO LOWER TEENS FOR CONVERSE AND NIOBRARA COUNTIES. TEMPERATURES
WILL REMAIN WARM OVER THE COURSE OF THE WEEK WITH POPS BEING LOW.
A FEW ISOLATED THUNDERSTORMS MAY BE SEEN OVER THE SIERRA MADRES
AND SNOWY RANGES ON WEDNESDAY. THURSDAY AND FRIDAY ARE EXPECTED TO
CONTINUE THIS HOT/DRY TREND. THIS PATTERN WILL CHANGE OVER THE
WEEKEND WHEN A UPPER LEVEL TROUGH IS PROJECTED TO MOVE EASTWARD
FROM THE PACIFIC NORTHWEST. A WEAK COLD FRONT PASSAGE ON SATURDAY
WILL BRING SOME SCATTERED SHOWERS AND THUNDERSTORMS...MAINLY
AFFECTING EAST OF THE LARAMIE RANGE INTO THE NEBRASKA PANHANDLE.
THE PASSAGE OF AN UPPER LEVEL TROUGH ON SUNDAY WILL BRING
TEMPERATURES AS WELL AS A CONTINUED CHANCE OF THUNDERSTORMS FOR
THE NEBRASKA PANHANDLE.


&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1120 AM MDT SUN AUG 30 2015

SCATTERED THUNDERSTORMS THIS AFTERNOON...FOR RAWLINS AND LARAMIE
AS AN UPPER LEVEL DISTURBANCE MOVES ACROSS THE FORECAST AREA.
CHEYENNE COULD SEE SOME ISOLATED SHOWERS LATER INTO THE NIGHT.
BRIEF MVFR CONDITIONS CAN BE SEEN WITH A PASSING THUNDERSTORM.
OTHERWISE EXPECT VFR CONDITIONS THROUGHOUT THE DAY. WINDS ARE
EXPECTED TO PICK UP THROUGHOUT THE AFTERNOON HOURS FOR THE
NEBRASKA PANHANDLE. OVERNIGHT WINDS WILL CONTINUE TO BE GUSTY FOR
CHADRON WITH THE DEVELOPMENT OF A LLVL JET.


&&

.FIRE WEATHER...
ISSUED AT 157 PM MDT SUN AUG 30 2015

MAINLY DRY AND WARM THROUGH THIS WEEK ALTHOUGH THERE WILL
BE SOME CHANCES FOR WETTING RAINS. A FRONTAL BOUNDARY WILL
BRING SCATTERED SHOWERS AND A FEW THUNDERSTORMS TO THE AREA
INTO THIS EVENING. WIND GUSTS TO AROUND 55 MPH WILL OCCUR
WITH SOME SHOWERS AND THUNDERSTORMS INTO THIS EVENING.

COOLER TEMPERATURES MONDAY WILL SUPPRESS CRITICAL FIRE
WEATHER POTENTIAL BUT LATER INTO THE WEEK TEMPERATURES WILL
BE UNSEASONABLY WARM WITH HUMIDITIES DROPPING INTO THE 10
TO 15 PERCENT RANGE ACROSS SOUTHEAST WYOMING. WINDS WILL
BE GUSTY SEVERAL AFTERNOONS DURING THE WEEK SUCH THAT
CRITICAL FIRE THRESHOLDS MAY BE REACHED.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...RED FLAG WARNING UNTIL 7 PM MDT THIS EVENING FOR WYZ301.

NE...NONE.

&&

$$

SHORT TERM...SML
LONG TERM...GCC
AVIATION...GCC
FIRE WEATHER...SML



000
FXUS65 KCYS 302152
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
352 PM MDT SUN AUG 30 2015

.SHORT TERM...(THIS EVENING THROUGH TUESDAY NIGHT)

ISSUED AT 300 PM MDT SUN AUG 30 2015

SCATTERED LIGHT SHOWERS AND ISOLATED THUNDERSTORMS WILL
MOVE ACROSS SOUTHEAST WYOMING THIS AFTERNOON AND EVENING. SOME OF
THIS ACTIVITY MAY REACH THE NEBRASKA PANHANDLE. 40 TO 50 SPREADS
BETWEEN TEMPERATURES AND DEWPOINTS WILL MAKE IT TOUGH FOR MOISTURE
TO REACH THE GROUND SUCH THAT MEASURABLE RAIN WILL BE MINIMAL
WHERE IT DOES REACH THE SURFACE. THE LARGE SPREADS BETWEEN
TEMPERATURE AND DEW POINTS WILL PRODUCE THE POTENTIAL FOR
RELATIVELY STRONG DOWN DRAFTS CAPABLE OF PRODUCING WIND GUSTS OF
50 TO 60 MPH...IF NOT GREATER. COW CREEK RAWS ALREADY MEASURED A
GUST OF 54 MPH AT 243 PM. COOLING ALOFT...THE REAR ENTRANCE OF AN
UPPER LEVEL JET...AND MOIST MID FLOW MAY KEEP SOME SHOWER
ACTIVITY LINGERING INTO THE OVERNIGHT HOURS BUT STRONG WIND GUST
POTENTIAL WILL SUBSIDE.

MONDAY WILL SEE A BREAK IN THE VERY WARM TEMPERATURES WITH HIGHS
TYPICALLY IN THE 80S ACROSS THE FORECAST AREA. MID LEVEL MOISTURE
IS PROGGED TO BE IN PLACE ACROSS SOUTHERN PORTIONS OF THE FORECAST
AREA WHICH SHOULD YIELD A FEW MORE AFTERNOON AND EVENING SHOWERS
AND THUNDERSTORMS. AGAIN SEVERE THUNDERSTORMS ARE NOT A CONCERN
BUT A FEW STRONGER WIND GUSTS MAY BE POSSIBLE.

WARMER TEMPERATURES RETURN TUESDAY AS THE RIDGE REBOUNDS ACROSS
THE NORTHERN ROCKIES. HIGH TEMPERATURES TO WARM INTO THE 90S
ACROSS THE PLAINS AND 80S FARTHER WEST. LESSER CHANCES FOR
PRECIPITATION TUESDAY BUT MAY SEE A COUPLE SHOWERS DEVELOP OFF THE
HIGHER TERRAIN.


.LONG TERM...(WEDNESDAY THROUGH SUNDAY)
ISSUED AT 300 PM MDT SUN AUG 30 2015

THERE WILL CONTINUE TO BE SOUTHWESTERLY FLOW ALOFT THROUGHOUT THE
MAJORITY OF THE WEEK. A DRY AIRMASS ALOFT ON WEDNESDAY COULD
BRING CONCERNS FOR FIRE WEATHER WITH RH VALUES DOWN INTO THE MID
TO LOWER TEENS FOR CONVERSE AND NIOBRARA COUNTIES. TEMPERATURES
WILL REMAIN WARM OVER THE COURSE OF THE WEEK WITH POPS BEING LOW.
A FEW ISOLATED THUNDERSTORMS MAY BE SEEN OVER THE SIERRA MADRES
AND SNOWY RANGES ON WEDNESDAY. THURSDAY AND FRIDAY ARE EXPECTED TO
CONTINUE THIS HOT/DRY TREND. THIS PATTERN WILL CHANGE OVER THE
WEEKEND WHEN A UPPER LEVEL TROUGH IS PROJECTED TO MOVE EASTWARD
FROM THE PACIFIC NORTHWEST. A WEAK COLD FRONT PASSAGE ON SATURDAY
WILL BRING SOME SCATTERED SHOWERS AND THUNDERSTORMS...MAINLY
AFFECTING EAST OF THE LARAMIE RANGE INTO THE NEBRASKA PANHANDLE.
THE PASSAGE OF AN UPPER LEVEL TROUGH ON SUNDAY WILL BRING
TEMPERATURES AS WELL AS A CONTINUED CHANCE OF THUNDERSTORMS FOR
THE NEBRASKA PANHANDLE.


&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1120 AM MDT SUN AUG 30 2015

SCATTERED THUNDERSTORMS THIS AFTERNOON...FOR RAWLINS AND LARAMIE
AS AN UPPER LEVEL DISTURBANCE MOVES ACROSS THE FORECAST AREA.
CHEYENNE COULD SEE SOME ISOLATED SHOWERS LATER INTO THE NIGHT.
BRIEF MVFR CONDITIONS CAN BE SEEN WITH A PASSING THUNDERSTORM.
OTHERWISE EXPECT VFR CONDITIONS THROUGHOUT THE DAY. WINDS ARE
EXPECTED TO PICK UP THROUGHOUT THE AFTERNOON HOURS FOR THE
NEBRASKA PANHANDLE. OVERNIGHT WINDS WILL CONTINUE TO BE GUSTY FOR
CHADRON WITH THE DEVELOPMENT OF A LLVL JET.


&&

.FIRE WEATHER...
ISSUED AT 157 PM MDT SUN AUG 30 2015

MAINLY DRY AND WARM THROUGH THIS WEEK ALTHOUGH THERE WILL
BE SOME CHANCES FOR WETTING RAINS. A FRONTAL BOUNDARY WILL
BRING SCATTERED SHOWERS AND A FEW THUNDERSTORMS TO THE AREA
INTO THIS EVENING. WIND GUSTS TO AROUND 55 MPH WILL OCCUR
WITH SOME SHOWERS AND THUNDERSTORMS INTO THIS EVENING.

COOLER TEMPERATURES MONDAY WILL SUPPRESS CRITICAL FIRE
WEATHER POTENTIAL BUT LATER INTO THE WEEK TEMPERATURES WILL
BE UNSEASONABLY WARM WITH HUMIDITIES DROPPING INTO THE 10
TO 15 PERCENT RANGE ACROSS SOUTHEAST WYOMING. WINDS WILL
BE GUSTY SEVERAL AFTERNOONS DURING THE WEEK SUCH THAT
CRITICAL FIRE THRESHOLDS MAY BE REACHED.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...RED FLAG WARNING UNTIL 7 PM MDT THIS EVENING FOR WYZ301.

NE...NONE.

&&

$$

SHORT TERM...SML
LONG TERM...GCC
AVIATION...GCC
FIRE WEATHER...SML




000
FXUS63 KUNR 302101
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
301 PM MDT SUN AUG 30 2015

.SHORT TERM...THIS EVENING THROUGH MONDAY NIGHT
ISSUED AT 300 PM MDT SUN AUG 30 2015

CURRENT SURFACE ANALYSIS SHOWS SLOW MOVING COLD FRONT FROM FAR
EASTERN MT THROUGH NORTHEAST INTO CENTRAL WY. UPPER LEVEL ANALYSIS
SHOWS POSITIVELY TILTED RIDGE FROM THE SOUTHERN ROCKIES INTO
EASTERN PORTIONS OF THE NORTHERN PLAINS. SOUTHWEST FLOW ALOFT
BEHIND THE RIDGE FROM THE GREAT BASIN TO THE NORTHERN HIGH PLAINS.
SKIES ARE MOSTLY SUNNY ACROSS EASTERN PORTIONS OF THE CWA...PARTLY
CLOUDY OVER NORTHEAST WY. REGIONAL RADARS SHOW BULK OF SHOWER AND
THUNDERSTORM ACTIVITY OVER NORTHEAST MT INTO NORTHWEST ND NEAR THE
FRONT...AS WELL AS OVER THE HIGHER TERRAIN OF CENTRAL WY. A FEW
SHOWERS AND STORMS ARE NOW DEVELOPING NEAR AND AHEAD OF THE FRONT
OVER NORTHEAST WY. TEMPS ARE IN THE 90S OVER MUCH OF THE
AREA...WITH SOME 80S OVER THE BLACK HILLS. WINDS ARE FROM THE
SOUTH TO SOUTHWEST... BREEZY OVER SOUTH CENTRAL SD AS WELL AS
PORTIONS OF NORTHEAST WY.

COLD FRONT WILL EVER SO SLOWLY CROSS THE FORECAST AREA LATE TODAY
AND TONIGHT...WEAKENING SOME AS IT REACHES SOUTH CENTRAL SD MONDAY
MORNING. MOSTLY ISOLATED SHOWERS AND THUNDERSTORMS CAN BE EXPECTED
WITH THE FRONTAL PASSAGE TONIGHT. THE BEST CHANCES WILL LIKELY BE
OVER FAR NORTHWEST SD THIS EVENING. THE THREAT FOR ANY STRONGER
STORMS WILL BE MINIMAL THROUGH THE EVENING AS CAPE VALUES REMAIN
RELATIVELY LOW ACROSS THE AREA...BUT SOME GUSTY WINDS ARE POSSIBLE.
WINDS WILL SWITCH TO THE WEST AND NORTHWEST BEHIND THE
FRONT...BECOMING BREEZY LATER TONIGHT AND EARLY MONDAY OVER MUCH OF
THE PLAINS. AHEAD OF THE FRONT...WINDS WILL REMAIN BREEZY FROM THE
SOUTH OVER SOUTH CENTRAL SD. LOWS WILL RANGE FROM THE 50S OVER
NORTHEAST WY AND THE BLACK HILLS TO AROUND 70 OVER SOUTH CENTRAL SD.

FRONT WILL SLOWLY SAG SOUTH AND EAST OF THE AREA ON MONDAY AND
FURTHER WEAKEN. WOULD NOT BE SURPRISED TO SEE A SHOWER OR
THUNDERSTORM OVER FAR SOUTHERN SD ON MONDAY IN CLOSER VICINITY TO
THE FRONT...ESPECIALLY SOUTH CENTRAL SD...BUT CHANCES LOOK BELOW 15
PERCENT SO WILL LEAVE FORECAST DRY. SOME COOLER AIR WILL BUILD INTO
THE AREA...WITH HIGHS IN THE 80S ACROSS THE PLAINS...70S IN THE
BLACK HILLS. BRISK NORTHWEST WINDS CAN BE EXPECTED ACROSS THE SD
PLAINS DURING THE DAY. MOSTLY CLEAR MONDAY NIGHT WITH LOWS NEAR OR
SLIGHTLY ABOVE SEASONAL AVERAGES.

.LONG TERM...TUESDAY THROUGH SUNDAY
ISSUED AT 300 PM MDT SUN AUG 30 2015

LONG WAVE TROUGH OVER WESTERN NOAM WILL REMAIN THROUGH
MID WEEK...WITH EVENTUAL BREAKDOWN PER AN ADVECTING STRONG NORTHERN
PAC IMPULSE. THIS WILL SUPPORT VERY WARM TEMPS THROUGH THURS. STRONG
SUPPORT AMONG DETERMINISTIC AND ENSEMBLE MODEL RUNS FOR A STRONG
COLD FRONT TO ADVECT TROUGH THE REGION NEXT WEEKEND AS THE PAC NW
UPPER TROUGH MERGES WITH A STRONG CENTRAL CANADIAN TROUGH.
HOWEVER...PRECIP CHANCES STILL LOOK LOW GIVEN LACK OF SUFFICIENT
MOISTURE WITH THE BULK OF LSA SHIFTING NORTH OF THE AREA. MUCH
COOLER TEMPS LOOK MORE LIKELY BY SUN-MON NEXT WEEK WITH HIGHS IN THE
50S-60S POSSIBLE BY THEN. MEANWHILE...DRY WEATHER IS EXPECTED TUE-
THUR...ALTHOUGH A WEAK SIGNAL REMAINS OVER SCENTRAL SD TUES WHERE A
LL TROUGH AND MOISTURE ADV ARE PROGGED. DID BUMPS TEMPS UP TUE-THUR
GIVEN WARM-DRY SW FLOW WITH WARMER TEMPS NOW PROGGED IN CONSENSUS
BLENDS. OTHERWISE...COOLER CONDS WILL ARRIVE FRI-SAT...HOW COOL WILL
DEPEND ON THE PROGRESSIVE NATURE OF THE UPPER TROUGH...WHICH IS A
LITTLE SLOWER IN THE ECMWF. MUCH COOLER CONDS EXPECTED BY EARLY NEXT
WEEK...ALONG WITH ISOLD-SCT SHRA.

&&

.AVIATION...FOR THE 18Z TAFS THROUGH 18Z MONDAY
ISSUED AT 300 PM MDT SUN AUG 30 2015

BREEZY SOUTHERLY WINDS WILL PREVAIL ACROSS THE AREA TODAY. MAINLY
VFR CONDITIONS ARE EXPECTED WITH ISOLD MVFR VSBYS POSSIBLE IN
SMOKE FROM WESTERN WILDFIRES. THERE IS A SLIGHT CHANCE OF
THUNDERSTORMS OVER NORTHEASTERN WYOMING AND FAR WESTERN SOUTH
DAKOTA FROM LATE THIS AFTERNOON THROUGH THIS EVENING. GUSTY WINDS
WILL BE POSSIBLE WITH ANY TS ACTIVITY. A COLD FRONT WILL PUSH
THROUGH THE AREA EARLY MONDAY MORNING...WITH A PERIOD OF GUSTY NW
WINDS EXPECTED BEHIND THE FRONT.

&&

.FIRE WEATHER...
ISSUED AT 300 PM MDT SUN AUG 30 2015

WARM AND DRY CONDITIONS WILL PERSIST ACROSS NE WY THIS
AFTERNOON...WITH RELATIVE HUMIDITY AROUND 15 PERCENT AND GUSTY
WESTERLY WINDS OF 20 TO 30 MPH. A FEW ISOLD TS ARE ALSO POSSIBLE
WITH DRY LIGHTNING AND GUSTY WINDS LIKELY WITH ANY TS. A COLD
FRONT WILL CROSS THE AREA TONIGHT WITH WINDS SHIFTING NW AND
REMAINING GUSTY FOR A FEW HOURS.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
WY...RED FLAG WARNING UNTIL 8 PM MDT THIS EVENING FOR WYZ259-297-298.

&&

$$

SHORT TERM...26
LONG TERM...JC
AVIATION...JC
FIRE WEATHER...JC



000
FXUS63 KUNR 302101
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
301 PM MDT SUN AUG 30 2015

.SHORT TERM...THIS EVENING THROUGH MONDAY NIGHT
ISSUED AT 300 PM MDT SUN AUG 30 2015

CURRENT SURFACE ANALYSIS SHOWS SLOW MOVING COLD FRONT FROM FAR
EASTERN MT THROUGH NORTHEAST INTO CENTRAL WY. UPPER LEVEL ANALYSIS
SHOWS POSITIVELY TILTED RIDGE FROM THE SOUTHERN ROCKIES INTO
EASTERN PORTIONS OF THE NORTHERN PLAINS. SOUTHWEST FLOW ALOFT
BEHIND THE RIDGE FROM THE GREAT BASIN TO THE NORTHERN HIGH PLAINS.
SKIES ARE MOSTLY SUNNY ACROSS EASTERN PORTIONS OF THE CWA...PARTLY
CLOUDY OVER NORTHEAST WY. REGIONAL RADARS SHOW BULK OF SHOWER AND
THUNDERSTORM ACTIVITY OVER NORTHEAST MT INTO NORTHWEST ND NEAR THE
FRONT...AS WELL AS OVER THE HIGHER TERRAIN OF CENTRAL WY. A FEW
SHOWERS AND STORMS ARE NOW DEVELOPING NEAR AND AHEAD OF THE FRONT
OVER NORTHEAST WY. TEMPS ARE IN THE 90S OVER MUCH OF THE
AREA...WITH SOME 80S OVER THE BLACK HILLS. WINDS ARE FROM THE
SOUTH TO SOUTHWEST... BREEZY OVER SOUTH CENTRAL SD AS WELL AS
PORTIONS OF NORTHEAST WY.

COLD FRONT WILL EVER SO SLOWLY CROSS THE FORECAST AREA LATE TODAY
AND TONIGHT...WEAKENING SOME AS IT REACHES SOUTH CENTRAL SD MONDAY
MORNING. MOSTLY ISOLATED SHOWERS AND THUNDERSTORMS CAN BE EXPECTED
WITH THE FRONTAL PASSAGE TONIGHT. THE BEST CHANCES WILL LIKELY BE
OVER FAR NORTHWEST SD THIS EVENING. THE THREAT FOR ANY STRONGER
STORMS WILL BE MINIMAL THROUGH THE EVENING AS CAPE VALUES REMAIN
RELATIVELY LOW ACROSS THE AREA...BUT SOME GUSTY WINDS ARE POSSIBLE.
WINDS WILL SWITCH TO THE WEST AND NORTHWEST BEHIND THE
FRONT...BECOMING BREEZY LATER TONIGHT AND EARLY MONDAY OVER MUCH OF
THE PLAINS. AHEAD OF THE FRONT...WINDS WILL REMAIN BREEZY FROM THE
SOUTH OVER SOUTH CENTRAL SD. LOWS WILL RANGE FROM THE 50S OVER
NORTHEAST WY AND THE BLACK HILLS TO AROUND 70 OVER SOUTH CENTRAL SD.

FRONT WILL SLOWLY SAG SOUTH AND EAST OF THE AREA ON MONDAY AND
FURTHER WEAKEN. WOULD NOT BE SURPRISED TO SEE A SHOWER OR
THUNDERSTORM OVER FAR SOUTHERN SD ON MONDAY IN CLOSER VICINITY TO
THE FRONT...ESPECIALLY SOUTH CENTRAL SD...BUT CHANCES LOOK BELOW 15
PERCENT SO WILL LEAVE FORECAST DRY. SOME COOLER AIR WILL BUILD INTO
THE AREA...WITH HIGHS IN THE 80S ACROSS THE PLAINS...70S IN THE
BLACK HILLS. BRISK NORTHWEST WINDS CAN BE EXPECTED ACROSS THE SD
PLAINS DURING THE DAY. MOSTLY CLEAR MONDAY NIGHT WITH LOWS NEAR OR
SLIGHTLY ABOVE SEASONAL AVERAGES.

.LONG TERM...TUESDAY THROUGH SUNDAY
ISSUED AT 300 PM MDT SUN AUG 30 2015

LONG WAVE TROUGH OVER WESTERN NOAM WILL REMAIN THROUGH
MID WEEK...WITH EVENTUAL BREAKDOWN PER AN ADVECTING STRONG NORTHERN
PAC IMPULSE. THIS WILL SUPPORT VERY WARM TEMPS THROUGH THURS. STRONG
SUPPORT AMONG DETERMINISTIC AND ENSEMBLE MODEL RUNS FOR A STRONG
COLD FRONT TO ADVECT TROUGH THE REGION NEXT WEEKEND AS THE PAC NW
UPPER TROUGH MERGES WITH A STRONG CENTRAL CANADIAN TROUGH.
HOWEVER...PRECIP CHANCES STILL LOOK LOW GIVEN LACK OF SUFFICIENT
MOISTURE WITH THE BULK OF LSA SHIFTING NORTH OF THE AREA. MUCH
COOLER TEMPS LOOK MORE LIKELY BY SUN-MON NEXT WEEK WITH HIGHS IN THE
50S-60S POSSIBLE BY THEN. MEANWHILE...DRY WEATHER IS EXPECTED TUE-
THUR...ALTHOUGH A WEAK SIGNAL REMAINS OVER SCENTRAL SD TUES WHERE A
LL TROUGH AND MOISTURE ADV ARE PROGGED. DID BUMPS TEMPS UP TUE-THUR
GIVEN WARM-DRY SW FLOW WITH WARMER TEMPS NOW PROGGED IN CONSENSUS
BLENDS. OTHERWISE...COOLER CONDS WILL ARRIVE FRI-SAT...HOW COOL WILL
DEPEND ON THE PROGRESSIVE NATURE OF THE UPPER TROUGH...WHICH IS A
LITTLE SLOWER IN THE ECMWF. MUCH COOLER CONDS EXPECTED BY EARLY NEXT
WEEK...ALONG WITH ISOLD-SCT SHRA.

&&

.AVIATION...FOR THE 18Z TAFS THROUGH 18Z MONDAY
ISSUED AT 300 PM MDT SUN AUG 30 2015

BREEZY SOUTHERLY WINDS WILL PREVAIL ACROSS THE AREA TODAY. MAINLY
VFR CONDITIONS ARE EXPECTED WITH ISOLD MVFR VSBYS POSSIBLE IN
SMOKE FROM WESTERN WILDFIRES. THERE IS A SLIGHT CHANCE OF
THUNDERSTORMS OVER NORTHEASTERN WYOMING AND FAR WESTERN SOUTH
DAKOTA FROM LATE THIS AFTERNOON THROUGH THIS EVENING. GUSTY WINDS
WILL BE POSSIBLE WITH ANY TS ACTIVITY. A COLD FRONT WILL PUSH
THROUGH THE AREA EARLY MONDAY MORNING...WITH A PERIOD OF GUSTY NW
WINDS EXPECTED BEHIND THE FRONT.

&&

.FIRE WEATHER...
ISSUED AT 300 PM MDT SUN AUG 30 2015

WARM AND DRY CONDITIONS WILL PERSIST ACROSS NE WY THIS
AFTERNOON...WITH RELATIVE HUMIDITY AROUND 15 PERCENT AND GUSTY
WESTERLY WINDS OF 20 TO 30 MPH. A FEW ISOLD TS ARE ALSO POSSIBLE
WITH DRY LIGHTNING AND GUSTY WINDS LIKELY WITH ANY TS. A COLD
FRONT WILL CROSS THE AREA TONIGHT WITH WINDS SHIFTING NW AND
REMAINING GUSTY FOR A FEW HOURS.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
WY...RED FLAG WARNING UNTIL 8 PM MDT THIS EVENING FOR WYZ259-297-298.

&&

$$

SHORT TERM...26
LONG TERM...JC
AVIATION...JC
FIRE WEATHER...JC




000
FXUS65 KRIW 302037
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
237 PM MDT SUN AUG 30 2015

.SHORT TERM...TONIGHT THROUGH MONDAY

A TROUGH AND COLD FRONT CONTINUE TO TRACK EASTWARD ACROSS THE
INTERMOUNTAIN WEST. THE COLD FRONT IS LYING NEAR THE MONTANA BORDER
AND IS EXPECTED TO SURGE SOUTHWARD AGAIN AROUND SUNSET WITH THE
MAIN PUSH ARRIVING TOWARD MIDNIGHT...THOUGH THE TIMING ON COLD
FRONTS CAN BE TRICKY AS THEY OFTEN MOVE FASTER THAN EXPECTED. WE
CAN CONTINUE TO EXPECT RED FLAG CONDITIONS SOUTH OF THE FRONT AND
MUCH COOLER AND MOIST CONDITIONS TO THE NORTH THROUGH THE EARLY
EVENING HOURS.

THERE IS ALSO SOME DECENT LIFT ON THE FRONT SIDE OF THIS TROUGH
WITH JET SUPPORT ALOFT...A THETA E RIDGE LYING APPROXIMATELY FROM
FLAMING GORGE TO KAYCEE...AND QG FORCING ARRIVING LATER IN THE
EVENING. AREAS WITH DECENT LOW LEVEL MOISTURE IN PLACE...ACROSS
THE WEST AND THE SOUTH...AND ON THE OTHER SIDE OF THE FRONT WILL
SEE WET THUNDERSTORMS AND AREAS LIKE THE SOUTHERN BIGHORN
BASIN...NATRONA COUNTY AND FREMONT COUNTY WILL SEE MAINLY DRY
THUNDERSTORMS THROUGH SUNSET...SHOWERS AND STORMS HAVE A BETTER
CHANCE OF PRODUCING A WETTING RAIN THEREAFTER.

MONDAY WILL BE DRY AGAIN BUT LESS WINDY AS WE LOSE THE GRADIENT AT
THE SURFACE AND ALOFT. TEMPERATURES WILL BE CLOSER TO SEASONAL
NORMS WITH HIGHS IN THE LOW TO MID 80S EAST...MID TO UPPER 70S
WEST AND SOUTH. A PLUME OF MOISTURE ACROSS COLORADO COULD BEGIN TO
POKE NORTH INTO SOUTHERN SWEETWATER COUNTY WITH A FEW STRAY
AFTERNOON STORMS POSSIBLE OTHERIWSE IT WILL BE DRY AND RAIN FREE.

.LONG TERM...MONDAY NIGHT THROUGH SUNDAY

MEDIUM-RANGE FORECAST MODELS ARE CONSISTENT AND AGAIN IN FAIRLY GOOD
AGREEMENT THROUGH THE FORECAST PERIOD. WEST-SOUTHWEST FLOW ALOFT ON
TUESDAY WILL BACK TO THE SOUTHWEST WEDNESDAY AND THURSDAY AS A
TROUGH DEEPENS OVER THE PACIFIC NORTHWEST. LIMITED MOISTURE IN
SOUTHWEST FLOW FOR TUESDAY...BUT SOME PRECIPITABLE WATER VALUES
AROUND 0.70 INCHES COULD LEAD TO WEAK CONVECTION IN JOHNSON AND
NATRONA COUNTIES. HOWEVER...WITH DEW POINTS IN THE 30S HAVE
CONTINUED A GENERALLY DRY FORECAST FOR NOW. SOUTHWEST FLOW ADVECTS
IN DRIER AIR FROM THE GREAT BASIN WEDNESDAY AND THURSDAY AND DO NOT
SEE MUCH IN THE WAY OF AVAILABLE MOISTURE FOR ANY CONVECTION.
SURFACE DEW POINTS WILL GENERALLY RANGE FROM 25-35F. ALSO...
WEDNESDAY LOOKS TO BE THE WARMEST DAY OF THE WEEK WITH TEMPERATURES
RUNNING ABOUT 5-10F ABOVE NORMAL AND THE NORTHERN BASINS PUSHING
INTO THE 90S AGAIN. THE COMBINATION OF THE UNSEASONABLY HOT
TEMPERATURES...LOW HUMIDITY...AND INCREASING SOUTHWEST WIND OF 15-30
MPH WILL VERY LIKELY LEAD TO CRITICAL FIRE WEATHER CONDITIONS FOR
WEDNESDAY AND MOST PROBABLY THURSDAY. MOST INTENSE WINDS WILL BE IN
THE CORRIDOR FROM ROCK SPRINGS TO CASPER. THOSE WITH FIRE WEATHER
INTERESTS SHOULD BE AWARE OF THE LIKELIHOOD OF THESE CONDITIONS FOR
WEDNESDAY AND THURSDAY AND BE ON THE ALERT FOR POSSIBLE HIHGLIGHTS
ISSUED EARLY THIS WEEK. FIRST UPPER LOW IN THE PACIFIC NORTHWEST
TROUGH WILL EJECT INTO ALBERTA THURSDAY. THIS UPPER LOW WILL QUICKLY
BE REPLACED BY ANOTHER SHORTWAVE THAT WILL DROP INTO THE BASE OF THE
TROUGH OVER THE INTERMOUNTAIN WEST FOR FRIDAY. UPPER FLOW WILL
PARALLEL SURFACE FRONT THAT WILL BE ORIENTED NORTHEAST-SOUTHWEST
JUST TO THE WEST OF WYOMING FOR FRIDAY. HAVE NUDGED TEMPERATURES UP
A TAD FOR FRIDAY AS IT DOES LOOK LIKE THE COOLER AIR WILL HANG BACK
ONE MORE DAY. AM STILL CONCERNED THAT FRIDAY MAY INDEED BE WARMER
THAN CURRENTLY FORECAST WITH COMPRESSIONAL WARMING AHEAD OF THE
APPROACHING FRONT/TROUGH. MOISTURE WILL RIDE ALONG OUR NORTHWESTERN
ZONES FOR FRIDAY AFTERNOON AND SATURDAY. THEREFORE...HAVE INCREASED
PRECIP CHANCES OVER YELLOWSTONE AND THE SURROUNDING MOUNTAINS.
ENERGY IN THE BASE OF THE TROUGH WILL BEGIN TO EJECT SATURDAY WHILE
AT THE SAME TIME A SURFACE LOW TAKES SHAPE TO OUR SOUTHEAST. THIS
WILL BRING THE COLD FRONT ACROSS THE FORECAST AREA SATURDAY. BOTH
THE ECMWF AND GFS HAVE THE FORECAST AREA DRY SLOTTED SATURDAY AS THE
UPPER LOW TRACKS TO OUR NORTH. BEST CHANCE FOR MEASURABLE PRECIP
OVER THE WEEKEND WILL BE ACROSS THE NORTHERN THIRD OF THE FORECAST
AREA CLOSEST TO THE UPPER LOW. SURFACE HIGH PUSHES INTO WYOMING
SUNDAY AND 700MB TEMPERATURES FALL INTO THE ZERO TO +4C RANGE ACROSS
THE NORTH. THIS WILL LEAD TO COOLER THAN AVERAGE TEMPERATURES FOR
SUNDAY IN ALL BUT SOUTHWEST AND FAR WEST WYOMING.

&&

.AVIATION.../00Z ISSUANCE/

A COLD FRONT WILL CONTINUE TO PUSH EAST ACROSS THE INTERMOUNTAIN
WEST WITH SFC WINDS GENERALLY FROM THE SOUTHWEST TO WEST ACROSS MUCH
OF THE STATE AHEAD OF THE COLD FRONT...WINDS WILL BRIEFLY SWITCH TO
THE NW BEHIND THE FRONT WITH SOME AREAS OF 30-40KT GUSTS BEHIND THE
FRONT VCNTY KBYG KPOY KU68. THE MAIN AREA OF ISOLD-SCT -TSRA VCNTY
AND SOUTH OF A KEVW- KLND- KCPR LINE WITH HIGH BASED WINDY STORMS
EXPECTED INTO THE EARLY EVENING. THE COLD FRONT WILL BRING DRIER AIR
AND GUSTY WEST WIND INTO NW WYOMING MID TO LATE THIS
AFTERNOON...PUSHING ACROSS NORTH AND CENTRAL WYOMING LATE THIS
EVENING. CLEAR SKIES AND DIMINISHING WIND WILL PREVAIL ACROSS THE
AREA BEHIND THE FRONT EARLY MONDAY MORNING.

&&

.FIRE WEATHER...

...RED FLAG WARNING FOR PORTIONS OF CENTRAL AND NORTHERN WYOMING
THROUGH THE EVENING HOURS...

A COLD FRONT ASSOCIATED WITH THE TROUGH DIGGING TO THE WEST REMAINS
IN THE AREA NEAR THE MONTANA BORDER THIS AFTERNOON WITH COOLER
TEMPERATURES AND MODERATE HUMIDITY TO THE NORTH OF IT AND RED FLAG
TO NEAR RED FLAG CONDITIONS JUST TO THE SOUTH OF IT. MODELS ARE
CALLING FOR SOUTHWEST FLOW TO OVERTAKE THE FRONT AND CAUSE IT TO
RETREAT BACK NORTH FOR THE LATE AFTERNOON HOURS. THE MAIN FRONTAL
SURGE WILL COME LATER TONIGHT WITH STEADY 25 TO 35 MPH WINDS IN
JOHNSON COUNTY AND NORTHERN BIGHORN COUNTY BEHIND THE
FRONT...EXTENDED THE NORTHERN RED FLAG WARNINGS TO 3AM TO COVER THE
FRONTAL PASSAGE THOUGH IT MAY HAPPEN SOONER.

IN ADDITION...ISOLATED TO WIDELY SCATTERED MIXED WET AND DRY
THUNDERSTORMS ARE EXPECTED TO CONTINUE TO DEVELOP INTO THE EVENING
HOURS...WITH A FEW PERSISTING INTO THE NIGHT...ESPECIALLY EAST OF
THE DIVIDE.

IT WILL BE DRY BEHIND THE FRONT FOR MONDAY BUT A BIT COOLER. THERE
WILL BE SOME 20MPH BREEZES IN THE AFTERNOON BUT RED FLAG CONDITIONS
ARE NOT EXPECTED.

IT SILL LOOKS LIKE THERE COULD BE WIDESPREAD RED FLAG CONDITIONS MID
WEEK...STAY TUNED FOR UPDATES ON THE NEXT SYSTEM.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...
RED FLAG WARNING UNTIL 9 PM MDT THIS EVENING FOR WYZ280-283-285-
289-300.

RED FLAG WARNING UNTIL 3 AM MDT MONDAY FOR WYZ275-276-281-282-
287.

&&

$$

SHORT TERM...ALLEN
LONG TERM...CNJ
AVIATION...ALLEN
FIRE WEATHER...ALLEN




000
FXUS65 KRIW 302037
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
237 PM MDT SUN AUG 30 2015

.SHORT TERM...TONIGHT THROUGH MONDAY

A TROUGH AND COLD FRONT CONTINUE TO TRACK EASTWARD ACROSS THE
INTERMOUNTAIN WEST. THE COLD FRONT IS LYING NEAR THE MONTANA BORDER
AND IS EXPECTED TO SURGE SOUTHWARD AGAIN AROUND SUNSET WITH THE
MAIN PUSH ARRIVING TOWARD MIDNIGHT...THOUGH THE TIMING ON COLD
FRONTS CAN BE TRICKY AS THEY OFTEN MOVE FASTER THAN EXPECTED. WE
CAN CONTINUE TO EXPECT RED FLAG CONDITIONS SOUTH OF THE FRONT AND
MUCH COOLER AND MOIST CONDITIONS TO THE NORTH THROUGH THE EARLY
EVENING HOURS.

THERE IS ALSO SOME DECENT LIFT ON THE FRONT SIDE OF THIS TROUGH
WITH JET SUPPORT ALOFT...A THETA E RIDGE LYING APPROXIMATELY FROM
FLAMING GORGE TO KAYCEE...AND QG FORCING ARRIVING LATER IN THE
EVENING. AREAS WITH DECENT LOW LEVEL MOISTURE IN PLACE...ACROSS
THE WEST AND THE SOUTH...AND ON THE OTHER SIDE OF THE FRONT WILL
SEE WET THUNDERSTORMS AND AREAS LIKE THE SOUTHERN BIGHORN
BASIN...NATRONA COUNTY AND FREMONT COUNTY WILL SEE MAINLY DRY
THUNDERSTORMS THROUGH SUNSET...SHOWERS AND STORMS HAVE A BETTER
CHANCE OF PRODUCING A WETTING RAIN THEREAFTER.

MONDAY WILL BE DRY AGAIN BUT LESS WINDY AS WE LOSE THE GRADIENT AT
THE SURFACE AND ALOFT. TEMPERATURES WILL BE CLOSER TO SEASONAL
NORMS WITH HIGHS IN THE LOW TO MID 80S EAST...MID TO UPPER 70S
WEST AND SOUTH. A PLUME OF MOISTURE ACROSS COLORADO COULD BEGIN TO
POKE NORTH INTO SOUTHERN SWEETWATER COUNTY WITH A FEW STRAY
AFTERNOON STORMS POSSIBLE OTHERIWSE IT WILL BE DRY AND RAIN FREE.

.LONG TERM...MONDAY NIGHT THROUGH SUNDAY

MEDIUM-RANGE FORECAST MODELS ARE CONSISTENT AND AGAIN IN FAIRLY GOOD
AGREEMENT THROUGH THE FORECAST PERIOD. WEST-SOUTHWEST FLOW ALOFT ON
TUESDAY WILL BACK TO THE SOUTHWEST WEDNESDAY AND THURSDAY AS A
TROUGH DEEPENS OVER THE PACIFIC NORTHWEST. LIMITED MOISTURE IN
SOUTHWEST FLOW FOR TUESDAY...BUT SOME PRECIPITABLE WATER VALUES
AROUND 0.70 INCHES COULD LEAD TO WEAK CONVECTION IN JOHNSON AND
NATRONA COUNTIES. HOWEVER...WITH DEW POINTS IN THE 30S HAVE
CONTINUED A GENERALLY DRY FORECAST FOR NOW. SOUTHWEST FLOW ADVECTS
IN DRIER AIR FROM THE GREAT BASIN WEDNESDAY AND THURSDAY AND DO NOT
SEE MUCH IN THE WAY OF AVAILABLE MOISTURE FOR ANY CONVECTION.
SURFACE DEW POINTS WILL GENERALLY RANGE FROM 25-35F. ALSO...
WEDNESDAY LOOKS TO BE THE WARMEST DAY OF THE WEEK WITH TEMPERATURES
RUNNING ABOUT 5-10F ABOVE NORMAL AND THE NORTHERN BASINS PUSHING
INTO THE 90S AGAIN. THE COMBINATION OF THE UNSEASONABLY HOT
TEMPERATURES...LOW HUMIDITY...AND INCREASING SOUTHWEST WIND OF 15-30
MPH WILL VERY LIKELY LEAD TO CRITICAL FIRE WEATHER CONDITIONS FOR
WEDNESDAY AND MOST PROBABLY THURSDAY. MOST INTENSE WINDS WILL BE IN
THE CORRIDOR FROM ROCK SPRINGS TO CASPER. THOSE WITH FIRE WEATHER
INTERESTS SHOULD BE AWARE OF THE LIKELIHOOD OF THESE CONDITIONS FOR
WEDNESDAY AND THURSDAY AND BE ON THE ALERT FOR POSSIBLE HIHGLIGHTS
ISSUED EARLY THIS WEEK. FIRST UPPER LOW IN THE PACIFIC NORTHWEST
TROUGH WILL EJECT INTO ALBERTA THURSDAY. THIS UPPER LOW WILL QUICKLY
BE REPLACED BY ANOTHER SHORTWAVE THAT WILL DROP INTO THE BASE OF THE
TROUGH OVER THE INTERMOUNTAIN WEST FOR FRIDAY. UPPER FLOW WILL
PARALLEL SURFACE FRONT THAT WILL BE ORIENTED NORTHEAST-SOUTHWEST
JUST TO THE WEST OF WYOMING FOR FRIDAY. HAVE NUDGED TEMPERATURES UP
A TAD FOR FRIDAY AS IT DOES LOOK LIKE THE COOLER AIR WILL HANG BACK
ONE MORE DAY. AM STILL CONCERNED THAT FRIDAY MAY INDEED BE WARMER
THAN CURRENTLY FORECAST WITH COMPRESSIONAL WARMING AHEAD OF THE
APPROACHING FRONT/TROUGH. MOISTURE WILL RIDE ALONG OUR NORTHWESTERN
ZONES FOR FRIDAY AFTERNOON AND SATURDAY. THEREFORE...HAVE INCREASED
PRECIP CHANCES OVER YELLOWSTONE AND THE SURROUNDING MOUNTAINS.
ENERGY IN THE BASE OF THE TROUGH WILL BEGIN TO EJECT SATURDAY WHILE
AT THE SAME TIME A SURFACE LOW TAKES SHAPE TO OUR SOUTHEAST. THIS
WILL BRING THE COLD FRONT ACROSS THE FORECAST AREA SATURDAY. BOTH
THE ECMWF AND GFS HAVE THE FORECAST AREA DRY SLOTTED SATURDAY AS THE
UPPER LOW TRACKS TO OUR NORTH. BEST CHANCE FOR MEASURABLE PRECIP
OVER THE WEEKEND WILL BE ACROSS THE NORTHERN THIRD OF THE FORECAST
AREA CLOSEST TO THE UPPER LOW. SURFACE HIGH PUSHES INTO WYOMING
SUNDAY AND 700MB TEMPERATURES FALL INTO THE ZERO TO +4C RANGE ACROSS
THE NORTH. THIS WILL LEAD TO COOLER THAN AVERAGE TEMPERATURES FOR
SUNDAY IN ALL BUT SOUTHWEST AND FAR WEST WYOMING.

&&

.AVIATION.../00Z ISSUANCE/

A COLD FRONT WILL CONTINUE TO PUSH EAST ACROSS THE INTERMOUNTAIN
WEST WITH SFC WINDS GENERALLY FROM THE SOUTHWEST TO WEST ACROSS MUCH
OF THE STATE AHEAD OF THE COLD FRONT...WINDS WILL BRIEFLY SWITCH TO
THE NW BEHIND THE FRONT WITH SOME AREAS OF 30-40KT GUSTS BEHIND THE
FRONT VCNTY KBYG KPOY KU68. THE MAIN AREA OF ISOLD-SCT -TSRA VCNTY
AND SOUTH OF A KEVW- KLND- KCPR LINE WITH HIGH BASED WINDY STORMS
EXPECTED INTO THE EARLY EVENING. THE COLD FRONT WILL BRING DRIER AIR
AND GUSTY WEST WIND INTO NW WYOMING MID TO LATE THIS
AFTERNOON...PUSHING ACROSS NORTH AND CENTRAL WYOMING LATE THIS
EVENING. CLEAR SKIES AND DIMINISHING WIND WILL PREVAIL ACROSS THE
AREA BEHIND THE FRONT EARLY MONDAY MORNING.

&&

.FIRE WEATHER...

...RED FLAG WARNING FOR PORTIONS OF CENTRAL AND NORTHERN WYOMING
THROUGH THE EVENING HOURS...

A COLD FRONT ASSOCIATED WITH THE TROUGH DIGGING TO THE WEST REMAINS
IN THE AREA NEAR THE MONTANA BORDER THIS AFTERNOON WITH COOLER
TEMPERATURES AND MODERATE HUMIDITY TO THE NORTH OF IT AND RED FLAG
TO NEAR RED FLAG CONDITIONS JUST TO THE SOUTH OF IT. MODELS ARE
CALLING FOR SOUTHWEST FLOW TO OVERTAKE THE FRONT AND CAUSE IT TO
RETREAT BACK NORTH FOR THE LATE AFTERNOON HOURS. THE MAIN FRONTAL
SURGE WILL COME LATER TONIGHT WITH STEADY 25 TO 35 MPH WINDS IN
JOHNSON COUNTY AND NORTHERN BIGHORN COUNTY BEHIND THE
FRONT...EXTENDED THE NORTHERN RED FLAG WARNINGS TO 3AM TO COVER THE
FRONTAL PASSAGE THOUGH IT MAY HAPPEN SOONER.

IN ADDITION...ISOLATED TO WIDELY SCATTERED MIXED WET AND DRY
THUNDERSTORMS ARE EXPECTED TO CONTINUE TO DEVELOP INTO THE EVENING
HOURS...WITH A FEW PERSISTING INTO THE NIGHT...ESPECIALLY EAST OF
THE DIVIDE.

IT WILL BE DRY BEHIND THE FRONT FOR MONDAY BUT A BIT COOLER. THERE
WILL BE SOME 20MPH BREEZES IN THE AFTERNOON BUT RED FLAG CONDITIONS
ARE NOT EXPECTED.

IT SILL LOOKS LIKE THERE COULD BE WIDESPREAD RED FLAG CONDITIONS MID
WEEK...STAY TUNED FOR UPDATES ON THE NEXT SYSTEM.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...
RED FLAG WARNING UNTIL 9 PM MDT THIS EVENING FOR WYZ280-283-285-
289-300.

RED FLAG WARNING UNTIL 3 AM MDT MONDAY FOR WYZ275-276-281-282-
287.

&&

$$

SHORT TERM...ALLEN
LONG TERM...CNJ
AVIATION...ALLEN
FIRE WEATHER...ALLEN



000
FXUS65 KRIW 301747 AAA
AFDRIW

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE RIVERTON WY
1147 AM MDT SUN AUG 30 2015

.PREV DISCUSSION... /ISSUED 250 AM MDT SUN AUG 30 2015/

.SHORT TERM...TODAY THROUGH TUESDAY NIGHT

A STRONG TROUGH OF LOW PRESSURE JUST OFF THE PACIFIC NORTHWEST COAST
HAS EJECTED A SHEARED UPPER LEVEL SHORTWAVE EASTWARD THAT APPEARS TO
BE LOCATED OVER NORTHERN IDAHO AND WESTERN MT. ACTIVE CONVECTION
CONTINUES OUT AHEAD OF THIS FEATURE ACROSS EASTERN IDAHO NEAR THE
WYOMING BORDER AND INTO YNP AT THE TIME OF THIS WRITING. IT WILL BE
AN EARLY SHOW FOR CONVECTION IN WESTERN WY TODAY WITH THESE STORMS
ABOUT TO SWEEP ACROSS FAR WEST WYOMING DURING THE REMAINDER OF THE
NIGHT. THEN THE MAIN TROUGH WILL APPROACH THE NORTHERN ROCKIES TODAY
FOR ANOTHER ROUND OF CONVECTION FIRING UP IN FAR WESTERN WY BY MID
DAY AHEAD OF THE MAIN TROUGH AND ASCT COLD FRONT. IN THE
MEANTIME...EAST OF THE DIVIDE...SOUTHWEST WINDS WILL INCREASE OVER
WHAT THEY WERE SATURDAY AS THEY DRAW IN SLIGHTLY HIGHER LOWER LEVEL
MOISTURE. INSTABILITY WILL BE IN PLACE OVER THE ENTIRE CWA BUT ONLY
SCANT MOISTURE TO WORK WITH TO PRODUCE THUNDERSTORMS EAST OF THE
DIVIDE...AT LEAST INITIALLY IN THE EARLY TO MID AFTERNOON. THERE
WILL BE A SEPARATE FINGER OF WEAK HIGH AND MID LEVEL MONSOON
MOISTURE THAT WILL STREAM IN ACROSS RKS AND CPR. HOWEVER THE BEST
INSTABILITY WILL BE IN PLACE ACROSS NORTHERN WY WHERE THE BEST CAPES
WILL BE. IT APPEARS THE BEST CHANCE OF ANY DRY LIGHTNING WILL OCCUR
ON THE PERIPHERY OF ANY HIGH BASED THUNDERSTORMS ALONG THE
AFOREMENTIONED WEAK MONSOON MOISTURE PLUME AS WELL AS ACROSS
NORTHERN WY EAST OF THE DIVIDE WHERE RELATIVELY HIGH BASED STORMS
WILL CORRELATE WITH THE BEST CAPES. DRY THUNDERSTORMS WILL MORPH
INTO MORE WET STORMS AS THE FRONT DRAWS NEAR. THE TROUGHPA WILL
SWEEP ACROSS THE CWA TONIGHT. THEN ON MONDAY...ANOTHER SURGE OF WEAK
MID/UPPER LEVEL MOISTURE WILL OVERLAP SOME LINGERING INSTABILITY
OVER EXTREME SOUTHERN WY WHERE SOME ISOLD T STORMS ARE EXPECTED.
THEN BY TUESDAY...ANOTHER CLOSED LOW WILL ESTABLISH ITSELF ALONG THE
SOUTHERN BC COAST. THIS LOW WILL EJECT A WEAK VORT LOBE EAST
NORTHEAST ACROSS THE NORTHERN ROCKIES THAT WILL RESULT IN ISOLD
CONVECTION...MAINLY OVER THE NW MTNS TUE AFTERNOON. TODAY WILL BE A
COUPLE OF DEGREES COOLER THAN SATURDAY AS CLOUDS AND SHOWER ACTIVITY
DECREASE THE SOLAR INSULATION. AFTERWARD...TEMPS WILL COOL A FEW
DEGREES MONDAY BEFORE WARMING BACK UP TUESDAY.

.LONG TERM...WEDNESDAY THROUGH SUNDAY

HIGH LATITUDE ENERGY CURRENTLY OVER AK AND THE BERING SEA AREA WILL
DIVE SWD INTO OUR PACNW TROUGH AS UPSTREAM ENERGY...TYPHOON
REMNANTS...PUMPS UP THE UPSTREAM RIDGE OVER THE ERN PACIFIC. THE
END RESULT IS A DEEPENING COLD EARLY SEPTEMBER TROUGH OVER THE
PACNW AND INTERMOUNTAIN WEST THE SECOND HALF OF NEXT WEEK THAT
GRADUALLY TRANSLATES EWD AS THE FLOW DEAMPLIFYS TOWARDS THE END OF
THE PERIOD AND POSSIBLE SPLIT DEVELOPS OVER THE WEST EARLY NEXT
WEEK. THE MIDWEEK PERIOD WILL GENERALLY BE DRY AND QUITE WARM WITH
BREEZY TO LOCALLY WINDY PERIODS AND VERY LIMITED MAINLY MTN TSTMS
CHANCES AT BEST. BY FRIDAY...THE FIRST SIGNIFICANT SHORTWAVE OUT
AHEAD OF THE TROUGH IS ALREADY IMPACTING THE WEST AND NORTH AS A
COLD FRONT TRIES TO SAG SWD INTO THE NRN ZONES. THIS FRONTAL
BOUNDARY WILL BE A SIGNIFICANT PLAYER THROUGH THE WEEKEND WITH
CONSIDERABLY COOLER IF NOT COLDER WEATHER BEHIND IT AS THE MAIN
TROUGH OPENS UP AND PASSES ACROSS NRN WYO AND MONTANA OVER THE
LABOR DAY WEEKEND. A GOOD CHANCE OF SHOWERS AND TSTMS SHOULD OCCUR
IN AT LEAST THE NWRN SECTIONS WITH THIS FIRST SHORTWAVE AND THEN
MORE OF THE WEST AND NORTH AS THE DYNAMICS INTERACT/OVERRUN THE
FRONTAL BOUNDARY OVER THE WEEKEND. DETAILS ARE STILL UNCERTAIN BUT
THE GFS AND ECMWF ARE IN PRETTY GOOD AGREEMENT WITH THE BIG
PICTURE. THE SOURCE REGION OF THIS TROUGH IS QUITE COLD AND MODEL
GUIDANCE IS DROPPING H7 TEMPS DOWN TO AROUND ZERO TO EVEN BELOW
WITH THE FIRST SHORTWAVE FRIDAY NIGHT AND THEN WITH THE MAIN
TROUGH SATURDAY NIGHT SO MOUNTAINS WOULD GET A DECENT SHOT OF SOME
SNOW WITH EACH OF THESE. IT IS LABOR DAY WEEKEND AFTER ALL.

.AVIATION.../18Z ISSUANCE/

A COLD FRONT WILL CONTINUE TO PUSH EAST ACROSS THE INTERMOUNTAIN
WEST TODAY WITH SFC SW FLOW INCREASING ACROSS WEST AND CENTRAL
WYOMING AHEAD OF THE FRONT...ALONG WITH AREAS OF LLWS.  SFC SW WINDS
AT 20-30KTS WILL PREVAIL ACROSS THE AREA INTO THIS AFTERNOON. THE
MAIN AREA ISOLD-SCT -TSRA ARE DEVELOPING VCNTY AND SOUTH OF A
KEVW- KLND- KCPR LINE WITH HIGH BASED WINDY STORMS EXPECTED INTO
THE EARLY EVENING. THE COLD FRONT WILL BRING DRIER AIR AND GUSTY
WEST WIND INTO NW WYOMING MID TO LATE THIS AFTERNOON...PUSHING
ACROSS NORTH AND CENTRAL WYOMING THIS EVENING. CLEAR SKIES AND
DIMINISHING WIND WILL PREVAIL ACROSS THE AREA BEHIND THE FRONT
EARLY MONDAY MORNING.

.FIRE WEATHER...

...RED FLAG WARNING FOR PORTIONS OF CENTRAL AND NORTHERN WYOMING...

OVERALL IT WILL BE WINDIER THAN IT WAS SATURDAY BUT WITH SLIGHTLY
HIGHER RELATIVE HUMIDITY. AS THE COLD FRONT ASSOCIATED WITH THE
TROUGH DIGGING TO THE WEST ADVANCES...IT WILL LIKELY SETTLE INTO
WESTERN...NORTHERN AND SOUTHERN WYOMING FAIRLY EARLY IN THE
DAY...WHICH WOULD END THE FIRE WEATHER THREAT IN THOSE LOCATIONS
ALONG WITH INCREASING CLOUDS AS WELL AS A SLIGHT CHANCE FOR A
WETTING RAIN. STRONG SOUTHWEST FLOW BUT STILL LOW HUMIDITY ACROSS
FREMONT...JOHNSON AND NATRONA COUNTIES WILL OCCUR SO THESE AREAS
WILL CONTINUE TO BE UNDER THE RED FLAG WARNING FOR TODAY. IN
ADDITION...A SWATH OF MID LEVEL MOISTURE AND CONTINUED INSTABILITY
WILL KICK OF A FEW MIXED WET AND DRY THUNDERSTORMS...SOME OF WHICH
COULD CONTRIBUTE TO NEW FIRE STARTS WITH THE MOST ACTIVITY
EXPECTED ACROSS NORTHERN AND WESTERN WYOMING...WITH A SECONDARY
SWATH EXPECTED OVER NATRONA AND EASTERN FREMONT COUNTIES LATE
SUNDAY AFTERNOON...THE CHANCE OF A WETTING RAIN OUT OF THESE
STORMS IS NEXT TO ZERO. THE BEST CHANCE OF ANY DRY LIGHTNING
STARTS WILL LIKELY BE ON THE PERIPHERY OF ANY THUNDERSTORMS THAT
FORM ACROSS NORTHERN WYOMING EAST OF THE DIVIDE THROUGH MID DAY
WHERE THE BEST INSTABILITY WILL BE...THEN FROM EASTERN SWEETWATER
COUNTY TO CASPER AND THE REST OF NATRONA COUNTY LATER IN THE
AFTERNOON WHERE THE COMBINATION OF DRIEST BOUNDARY LEVEL MOISTURE
AND WIDEST TEMP/DEW POINT SPREADS WILL LIE.

A REPEAT OF THESE CONDITIONS WILL BE POSSIBLE MID WEEK.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...
RED FLAG WARNING UNTIL 9 PM MDT THIS EVENING FOR WYZ280-283-285-
289-300.

RED FLAG WARNING UNTIL 3 AM MDT MONDAY FOR WYZ275-276-281-282-
287.

&&

$$

SHORT TERM...LIPSON
LONG TERM...SKRBAC
AVIATION...ALLEN
FIRE WEATHER...LIPSON




000
FXUS65 KRIW 301747 AAA
AFDRIW

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE RIVERTON WY
1147 AM MDT SUN AUG 30 2015

.PREV DISCUSSION... /ISSUED 250 AM MDT SUN AUG 30 2015/

.SHORT TERM...TODAY THROUGH TUESDAY NIGHT

A STRONG TROUGH OF LOW PRESSURE JUST OFF THE PACIFIC NORTHWEST COAST
HAS EJECTED A SHEARED UPPER LEVEL SHORTWAVE EASTWARD THAT APPEARS TO
BE LOCATED OVER NORTHERN IDAHO AND WESTERN MT. ACTIVE CONVECTION
CONTINUES OUT AHEAD OF THIS FEATURE ACROSS EASTERN IDAHO NEAR THE
WYOMING BORDER AND INTO YNP AT THE TIME OF THIS WRITING. IT WILL BE
AN EARLY SHOW FOR CONVECTION IN WESTERN WY TODAY WITH THESE STORMS
ABOUT TO SWEEP ACROSS FAR WEST WYOMING DURING THE REMAINDER OF THE
NIGHT. THEN THE MAIN TROUGH WILL APPROACH THE NORTHERN ROCKIES TODAY
FOR ANOTHER ROUND OF CONVECTION FIRING UP IN FAR WESTERN WY BY MID
DAY AHEAD OF THE MAIN TROUGH AND ASCT COLD FRONT. IN THE
MEANTIME...EAST OF THE DIVIDE...SOUTHWEST WINDS WILL INCREASE OVER
WHAT THEY WERE SATURDAY AS THEY DRAW IN SLIGHTLY HIGHER LOWER LEVEL
MOISTURE. INSTABILITY WILL BE IN PLACE OVER THE ENTIRE CWA BUT ONLY
SCANT MOISTURE TO WORK WITH TO PRODUCE THUNDERSTORMS EAST OF THE
DIVIDE...AT LEAST INITIALLY IN THE EARLY TO MID AFTERNOON. THERE
WILL BE A SEPARATE FINGER OF WEAK HIGH AND MID LEVEL MONSOON
MOISTURE THAT WILL STREAM IN ACROSS RKS AND CPR. HOWEVER THE BEST
INSTABILITY WILL BE IN PLACE ACROSS NORTHERN WY WHERE THE BEST CAPES
WILL BE. IT APPEARS THE BEST CHANCE OF ANY DRY LIGHTNING WILL OCCUR
ON THE PERIPHERY OF ANY HIGH BASED THUNDERSTORMS ALONG THE
AFOREMENTIONED WEAK MONSOON MOISTURE PLUME AS WELL AS ACROSS
NORTHERN WY EAST OF THE DIVIDE WHERE RELATIVELY HIGH BASED STORMS
WILL CORRELATE WITH THE BEST CAPES. DRY THUNDERSTORMS WILL MORPH
INTO MORE WET STORMS AS THE FRONT DRAWS NEAR. THE TROUGHPA WILL
SWEEP ACROSS THE CWA TONIGHT. THEN ON MONDAY...ANOTHER SURGE OF WEAK
MID/UPPER LEVEL MOISTURE WILL OVERLAP SOME LINGERING INSTABILITY
OVER EXTREME SOUTHERN WY WHERE SOME ISOLD T STORMS ARE EXPECTED.
THEN BY TUESDAY...ANOTHER CLOSED LOW WILL ESTABLISH ITSELF ALONG THE
SOUTHERN BC COAST. THIS LOW WILL EJECT A WEAK VORT LOBE EAST
NORTHEAST ACROSS THE NORTHERN ROCKIES THAT WILL RESULT IN ISOLD
CONVECTION...MAINLY OVER THE NW MTNS TUE AFTERNOON. TODAY WILL BE A
COUPLE OF DEGREES COOLER THAN SATURDAY AS CLOUDS AND SHOWER ACTIVITY
DECREASE THE SOLAR INSULATION. AFTERWARD...TEMPS WILL COOL A FEW
DEGREES MONDAY BEFORE WARMING BACK UP TUESDAY.

.LONG TERM...WEDNESDAY THROUGH SUNDAY

HIGH LATITUDE ENERGY CURRENTLY OVER AK AND THE BERING SEA AREA WILL
DIVE SWD INTO OUR PACNW TROUGH AS UPSTREAM ENERGY...TYPHOON
REMNANTS...PUMPS UP THE UPSTREAM RIDGE OVER THE ERN PACIFIC. THE
END RESULT IS A DEEPENING COLD EARLY SEPTEMBER TROUGH OVER THE
PACNW AND INTERMOUNTAIN WEST THE SECOND HALF OF NEXT WEEK THAT
GRADUALLY TRANSLATES EWD AS THE FLOW DEAMPLIFYS TOWARDS THE END OF
THE PERIOD AND POSSIBLE SPLIT DEVELOPS OVER THE WEST EARLY NEXT
WEEK. THE MIDWEEK PERIOD WILL GENERALLY BE DRY AND QUITE WARM WITH
BREEZY TO LOCALLY WINDY PERIODS AND VERY LIMITED MAINLY MTN TSTMS
CHANCES AT BEST. BY FRIDAY...THE FIRST SIGNIFICANT SHORTWAVE OUT
AHEAD OF THE TROUGH IS ALREADY IMPACTING THE WEST AND NORTH AS A
COLD FRONT TRIES TO SAG SWD INTO THE NRN ZONES. THIS FRONTAL
BOUNDARY WILL BE A SIGNIFICANT PLAYER THROUGH THE WEEKEND WITH
CONSIDERABLY COOLER IF NOT COLDER WEATHER BEHIND IT AS THE MAIN
TROUGH OPENS UP AND PASSES ACROSS NRN WYO AND MONTANA OVER THE
LABOR DAY WEEKEND. A GOOD CHANCE OF SHOWERS AND TSTMS SHOULD OCCUR
IN AT LEAST THE NWRN SECTIONS WITH THIS FIRST SHORTWAVE AND THEN
MORE OF THE WEST AND NORTH AS THE DYNAMICS INTERACT/OVERRUN THE
FRONTAL BOUNDARY OVER THE WEEKEND. DETAILS ARE STILL UNCERTAIN BUT
THE GFS AND ECMWF ARE IN PRETTY GOOD AGREEMENT WITH THE BIG
PICTURE. THE SOURCE REGION OF THIS TROUGH IS QUITE COLD AND MODEL
GUIDANCE IS DROPPING H7 TEMPS DOWN TO AROUND ZERO TO EVEN BELOW
WITH THE FIRST SHORTWAVE FRIDAY NIGHT AND THEN WITH THE MAIN
TROUGH SATURDAY NIGHT SO MOUNTAINS WOULD GET A DECENT SHOT OF SOME
SNOW WITH EACH OF THESE. IT IS LABOR DAY WEEKEND AFTER ALL.

.AVIATION.../18Z ISSUANCE/

A COLD FRONT WILL CONTINUE TO PUSH EAST ACROSS THE INTERMOUNTAIN
WEST TODAY WITH SFC SW FLOW INCREASING ACROSS WEST AND CENTRAL
WYOMING AHEAD OF THE FRONT...ALONG WITH AREAS OF LLWS.  SFC SW WINDS
AT 20-30KTS WILL PREVAIL ACROSS THE AREA INTO THIS AFTERNOON. THE
MAIN AREA ISOLD-SCT -TSRA ARE DEVELOPING VCNTY AND SOUTH OF A
KEVW- KLND- KCPR LINE WITH HIGH BASED WINDY STORMS EXPECTED INTO
THE EARLY EVENING. THE COLD FRONT WILL BRING DRIER AIR AND GUSTY
WEST WIND INTO NW WYOMING MID TO LATE THIS AFTERNOON...PUSHING
ACROSS NORTH AND CENTRAL WYOMING THIS EVENING. CLEAR SKIES AND
DIMINISHING WIND WILL PREVAIL ACROSS THE AREA BEHIND THE FRONT
EARLY MONDAY MORNING.

.FIRE WEATHER...

...RED FLAG WARNING FOR PORTIONS OF CENTRAL AND NORTHERN WYOMING...

OVERALL IT WILL BE WINDIER THAN IT WAS SATURDAY BUT WITH SLIGHTLY
HIGHER RELATIVE HUMIDITY. AS THE COLD FRONT ASSOCIATED WITH THE
TROUGH DIGGING TO THE WEST ADVANCES...IT WILL LIKELY SETTLE INTO
WESTERN...NORTHERN AND SOUTHERN WYOMING FAIRLY EARLY IN THE
DAY...WHICH WOULD END THE FIRE WEATHER THREAT IN THOSE LOCATIONS
ALONG WITH INCREASING CLOUDS AS WELL AS A SLIGHT CHANCE FOR A
WETTING RAIN. STRONG SOUTHWEST FLOW BUT STILL LOW HUMIDITY ACROSS
FREMONT...JOHNSON AND NATRONA COUNTIES WILL OCCUR SO THESE AREAS
WILL CONTINUE TO BE UNDER THE RED FLAG WARNING FOR TODAY. IN
ADDITION...A SWATH OF MID LEVEL MOISTURE AND CONTINUED INSTABILITY
WILL KICK OF A FEW MIXED WET AND DRY THUNDERSTORMS...SOME OF WHICH
COULD CONTRIBUTE TO NEW FIRE STARTS WITH THE MOST ACTIVITY
EXPECTED ACROSS NORTHERN AND WESTERN WYOMING...WITH A SECONDARY
SWATH EXPECTED OVER NATRONA AND EASTERN FREMONT COUNTIES LATE
SUNDAY AFTERNOON...THE CHANCE OF A WETTING RAIN OUT OF THESE
STORMS IS NEXT TO ZERO. THE BEST CHANCE OF ANY DRY LIGHTNING
STARTS WILL LIKELY BE ON THE PERIPHERY OF ANY THUNDERSTORMS THAT
FORM ACROSS NORTHERN WYOMING EAST OF THE DIVIDE THROUGH MID DAY
WHERE THE BEST INSTABILITY WILL BE...THEN FROM EASTERN SWEETWATER
COUNTY TO CASPER AND THE REST OF NATRONA COUNTY LATER IN THE
AFTERNOON WHERE THE COMBINATION OF DRIEST BOUNDARY LEVEL MOISTURE
AND WIDEST TEMP/DEW POINT SPREADS WILL LIE.

A REPEAT OF THESE CONDITIONS WILL BE POSSIBLE MID WEEK.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...
RED FLAG WARNING UNTIL 9 PM MDT THIS EVENING FOR WYZ280-283-285-
289-300.

RED FLAG WARNING UNTIL 3 AM MDT MONDAY FOR WYZ275-276-281-282-
287.

&&

$$

SHORT TERM...LIPSON
LONG TERM...SKRBAC
AVIATION...ALLEN
FIRE WEATHER...LIPSON




000
FXUS65 KRIW 301747 AAA
AFDRIW

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE RIVERTON WY
1147 AM MDT SUN AUG 30 2015

.PREV DISCUSSION... /ISSUED 250 AM MDT SUN AUG 30 2015/

.SHORT TERM...TODAY THROUGH TUESDAY NIGHT

A STRONG TROUGH OF LOW PRESSURE JUST OFF THE PACIFIC NORTHWEST COAST
HAS EJECTED A SHEARED UPPER LEVEL SHORTWAVE EASTWARD THAT APPEARS TO
BE LOCATED OVER NORTHERN IDAHO AND WESTERN MT. ACTIVE CONVECTION
CONTINUES OUT AHEAD OF THIS FEATURE ACROSS EASTERN IDAHO NEAR THE
WYOMING BORDER AND INTO YNP AT THE TIME OF THIS WRITING. IT WILL BE
AN EARLY SHOW FOR CONVECTION IN WESTERN WY TODAY WITH THESE STORMS
ABOUT TO SWEEP ACROSS FAR WEST WYOMING DURING THE REMAINDER OF THE
NIGHT. THEN THE MAIN TROUGH WILL APPROACH THE NORTHERN ROCKIES TODAY
FOR ANOTHER ROUND OF CONVECTION FIRING UP IN FAR WESTERN WY BY MID
DAY AHEAD OF THE MAIN TROUGH AND ASCT COLD FRONT. IN THE
MEANTIME...EAST OF THE DIVIDE...SOUTHWEST WINDS WILL INCREASE OVER
WHAT THEY WERE SATURDAY AS THEY DRAW IN SLIGHTLY HIGHER LOWER LEVEL
MOISTURE. INSTABILITY WILL BE IN PLACE OVER THE ENTIRE CWA BUT ONLY
SCANT MOISTURE TO WORK WITH TO PRODUCE THUNDERSTORMS EAST OF THE
DIVIDE...AT LEAST INITIALLY IN THE EARLY TO MID AFTERNOON. THERE
WILL BE A SEPARATE FINGER OF WEAK HIGH AND MID LEVEL MONSOON
MOISTURE THAT WILL STREAM IN ACROSS RKS AND CPR. HOWEVER THE BEST
INSTABILITY WILL BE IN PLACE ACROSS NORTHERN WY WHERE THE BEST CAPES
WILL BE. IT APPEARS THE BEST CHANCE OF ANY DRY LIGHTNING WILL OCCUR
ON THE PERIPHERY OF ANY HIGH BASED THUNDERSTORMS ALONG THE
AFOREMENTIONED WEAK MONSOON MOISTURE PLUME AS WELL AS ACROSS
NORTHERN WY EAST OF THE DIVIDE WHERE RELATIVELY HIGH BASED STORMS
WILL CORRELATE WITH THE BEST CAPES. DRY THUNDERSTORMS WILL MORPH
INTO MORE WET STORMS AS THE FRONT DRAWS NEAR. THE TROUGHPA WILL
SWEEP ACROSS THE CWA TONIGHT. THEN ON MONDAY...ANOTHER SURGE OF WEAK
MID/UPPER LEVEL MOISTURE WILL OVERLAP SOME LINGERING INSTABILITY
OVER EXTREME SOUTHERN WY WHERE SOME ISOLD T STORMS ARE EXPECTED.
THEN BY TUESDAY...ANOTHER CLOSED LOW WILL ESTABLISH ITSELF ALONG THE
SOUTHERN BC COAST. THIS LOW WILL EJECT A WEAK VORT LOBE EAST
NORTHEAST ACROSS THE NORTHERN ROCKIES THAT WILL RESULT IN ISOLD
CONVECTION...MAINLY OVER THE NW MTNS TUE AFTERNOON. TODAY WILL BE A
COUPLE OF DEGREES COOLER THAN SATURDAY AS CLOUDS AND SHOWER ACTIVITY
DECREASE THE SOLAR INSULATION. AFTERWARD...TEMPS WILL COOL A FEW
DEGREES MONDAY BEFORE WARMING BACK UP TUESDAY.

.LONG TERM...WEDNESDAY THROUGH SUNDAY

HIGH LATITUDE ENERGY CURRENTLY OVER AK AND THE BERING SEA AREA WILL
DIVE SWD INTO OUR PACNW TROUGH AS UPSTREAM ENERGY...TYPHOON
REMNANTS...PUMPS UP THE UPSTREAM RIDGE OVER THE ERN PACIFIC. THE
END RESULT IS A DEEPENING COLD EARLY SEPTEMBER TROUGH OVER THE
PACNW AND INTERMOUNTAIN WEST THE SECOND HALF OF NEXT WEEK THAT
GRADUALLY TRANSLATES EWD AS THE FLOW DEAMPLIFYS TOWARDS THE END OF
THE PERIOD AND POSSIBLE SPLIT DEVELOPS OVER THE WEST EARLY NEXT
WEEK. THE MIDWEEK PERIOD WILL GENERALLY BE DRY AND QUITE WARM WITH
BREEZY TO LOCALLY WINDY PERIODS AND VERY LIMITED MAINLY MTN TSTMS
CHANCES AT BEST. BY FRIDAY...THE FIRST SIGNIFICANT SHORTWAVE OUT
AHEAD OF THE TROUGH IS ALREADY IMPACTING THE WEST AND NORTH AS A
COLD FRONT TRIES TO SAG SWD INTO THE NRN ZONES. THIS FRONTAL
BOUNDARY WILL BE A SIGNIFICANT PLAYER THROUGH THE WEEKEND WITH
CONSIDERABLY COOLER IF NOT COLDER WEATHER BEHIND IT AS THE MAIN
TROUGH OPENS UP AND PASSES ACROSS NRN WYO AND MONTANA OVER THE
LABOR DAY WEEKEND. A GOOD CHANCE OF SHOWERS AND TSTMS SHOULD OCCUR
IN AT LEAST THE NWRN SECTIONS WITH THIS FIRST SHORTWAVE AND THEN
MORE OF THE WEST AND NORTH AS THE DYNAMICS INTERACT/OVERRUN THE
FRONTAL BOUNDARY OVER THE WEEKEND. DETAILS ARE STILL UNCERTAIN BUT
THE GFS AND ECMWF ARE IN PRETTY GOOD AGREEMENT WITH THE BIG
PICTURE. THE SOURCE REGION OF THIS TROUGH IS QUITE COLD AND MODEL
GUIDANCE IS DROPPING H7 TEMPS DOWN TO AROUND ZERO TO EVEN BELOW
WITH THE FIRST SHORTWAVE FRIDAY NIGHT AND THEN WITH THE MAIN
TROUGH SATURDAY NIGHT SO MOUNTAINS WOULD GET A DECENT SHOT OF SOME
SNOW WITH EACH OF THESE. IT IS LABOR DAY WEEKEND AFTER ALL.

.AVIATION.../18Z ISSUANCE/

A COLD FRONT WILL CONTINUE TO PUSH EAST ACROSS THE INTERMOUNTAIN
WEST TODAY WITH SFC SW FLOW INCREASING ACROSS WEST AND CENTRAL
WYOMING AHEAD OF THE FRONT...ALONG WITH AREAS OF LLWS.  SFC SW WINDS
AT 20-30KTS WILL PREVAIL ACROSS THE AREA INTO THIS AFTERNOON. THE
MAIN AREA ISOLD-SCT -TSRA ARE DEVELOPING VCNTY AND SOUTH OF A
KEVW- KLND- KCPR LINE WITH HIGH BASED WINDY STORMS EXPECTED INTO
THE EARLY EVENING. THE COLD FRONT WILL BRING DRIER AIR AND GUSTY
WEST WIND INTO NW WYOMING MID TO LATE THIS AFTERNOON...PUSHING
ACROSS NORTH AND CENTRAL WYOMING THIS EVENING. CLEAR SKIES AND
DIMINISHING WIND WILL PREVAIL ACROSS THE AREA BEHIND THE FRONT
EARLY MONDAY MORNING.

.FIRE WEATHER...

...RED FLAG WARNING FOR PORTIONS OF CENTRAL AND NORTHERN WYOMING...

OVERALL IT WILL BE WINDIER THAN IT WAS SATURDAY BUT WITH SLIGHTLY
HIGHER RELATIVE HUMIDITY. AS THE COLD FRONT ASSOCIATED WITH THE
TROUGH DIGGING TO THE WEST ADVANCES...IT WILL LIKELY SETTLE INTO
WESTERN...NORTHERN AND SOUTHERN WYOMING FAIRLY EARLY IN THE
DAY...WHICH WOULD END THE FIRE WEATHER THREAT IN THOSE LOCATIONS
ALONG WITH INCREASING CLOUDS AS WELL AS A SLIGHT CHANCE FOR A
WETTING RAIN. STRONG SOUTHWEST FLOW BUT STILL LOW HUMIDITY ACROSS
FREMONT...JOHNSON AND NATRONA COUNTIES WILL OCCUR SO THESE AREAS
WILL CONTINUE TO BE UNDER THE RED FLAG WARNING FOR TODAY. IN
ADDITION...A SWATH OF MID LEVEL MOISTURE AND CONTINUED INSTABILITY
WILL KICK OF A FEW MIXED WET AND DRY THUNDERSTORMS...SOME OF WHICH
COULD CONTRIBUTE TO NEW FIRE STARTS WITH THE MOST ACTIVITY
EXPECTED ACROSS NORTHERN AND WESTERN WYOMING...WITH A SECONDARY
SWATH EXPECTED OVER NATRONA AND EASTERN FREMONT COUNTIES LATE
SUNDAY AFTERNOON...THE CHANCE OF A WETTING RAIN OUT OF THESE
STORMS IS NEXT TO ZERO. THE BEST CHANCE OF ANY DRY LIGHTNING
STARTS WILL LIKELY BE ON THE PERIPHERY OF ANY THUNDERSTORMS THAT
FORM ACROSS NORTHERN WYOMING EAST OF THE DIVIDE THROUGH MID DAY
WHERE THE BEST INSTABILITY WILL BE...THEN FROM EASTERN SWEETWATER
COUNTY TO CASPER AND THE REST OF NATRONA COUNTY LATER IN THE
AFTERNOON WHERE THE COMBINATION OF DRIEST BOUNDARY LEVEL MOISTURE
AND WIDEST TEMP/DEW POINT SPREADS WILL LIE.

A REPEAT OF THESE CONDITIONS WILL BE POSSIBLE MID WEEK.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...
RED FLAG WARNING UNTIL 9 PM MDT THIS EVENING FOR WYZ280-283-285-
289-300.

RED FLAG WARNING UNTIL 3 AM MDT MONDAY FOR WYZ275-276-281-282-
287.

&&

$$

SHORT TERM...LIPSON
LONG TERM...SKRBAC
AVIATION...ALLEN
FIRE WEATHER...LIPSON




000
FXUS65 KRIW 301747 AAA
AFDRIW

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE RIVERTON WY
1147 AM MDT SUN AUG 30 2015

.PREV DISCUSSION... /ISSUED 250 AM MDT SUN AUG 30 2015/

.SHORT TERM...TODAY THROUGH TUESDAY NIGHT

A STRONG TROUGH OF LOW PRESSURE JUST OFF THE PACIFIC NORTHWEST COAST
HAS EJECTED A SHEARED UPPER LEVEL SHORTWAVE EASTWARD THAT APPEARS TO
BE LOCATED OVER NORTHERN IDAHO AND WESTERN MT. ACTIVE CONVECTION
CONTINUES OUT AHEAD OF THIS FEATURE ACROSS EASTERN IDAHO NEAR THE
WYOMING BORDER AND INTO YNP AT THE TIME OF THIS WRITING. IT WILL BE
AN EARLY SHOW FOR CONVECTION IN WESTERN WY TODAY WITH THESE STORMS
ABOUT TO SWEEP ACROSS FAR WEST WYOMING DURING THE REMAINDER OF THE
NIGHT. THEN THE MAIN TROUGH WILL APPROACH THE NORTHERN ROCKIES TODAY
FOR ANOTHER ROUND OF CONVECTION FIRING UP IN FAR WESTERN WY BY MID
DAY AHEAD OF THE MAIN TROUGH AND ASCT COLD FRONT. IN THE
MEANTIME...EAST OF THE DIVIDE...SOUTHWEST WINDS WILL INCREASE OVER
WHAT THEY WERE SATURDAY AS THEY DRAW IN SLIGHTLY HIGHER LOWER LEVEL
MOISTURE. INSTABILITY WILL BE IN PLACE OVER THE ENTIRE CWA BUT ONLY
SCANT MOISTURE TO WORK WITH TO PRODUCE THUNDERSTORMS EAST OF THE
DIVIDE...AT LEAST INITIALLY IN THE EARLY TO MID AFTERNOON. THERE
WILL BE A SEPARATE FINGER OF WEAK HIGH AND MID LEVEL MONSOON
MOISTURE THAT WILL STREAM IN ACROSS RKS AND CPR. HOWEVER THE BEST
INSTABILITY WILL BE IN PLACE ACROSS NORTHERN WY WHERE THE BEST CAPES
WILL BE. IT APPEARS THE BEST CHANCE OF ANY DRY LIGHTNING WILL OCCUR
ON THE PERIPHERY OF ANY HIGH BASED THUNDERSTORMS ALONG THE
AFOREMENTIONED WEAK MONSOON MOISTURE PLUME AS WELL AS ACROSS
NORTHERN WY EAST OF THE DIVIDE WHERE RELATIVELY HIGH BASED STORMS
WILL CORRELATE WITH THE BEST CAPES. DRY THUNDERSTORMS WILL MORPH
INTO MORE WET STORMS AS THE FRONT DRAWS NEAR. THE TROUGHPA WILL
SWEEP ACROSS THE CWA TONIGHT. THEN ON MONDAY...ANOTHER SURGE OF WEAK
MID/UPPER LEVEL MOISTURE WILL OVERLAP SOME LINGERING INSTABILITY
OVER EXTREME SOUTHERN WY WHERE SOME ISOLD T STORMS ARE EXPECTED.
THEN BY TUESDAY...ANOTHER CLOSED LOW WILL ESTABLISH ITSELF ALONG THE
SOUTHERN BC COAST. THIS LOW WILL EJECT A WEAK VORT LOBE EAST
NORTHEAST ACROSS THE NORTHERN ROCKIES THAT WILL RESULT IN ISOLD
CONVECTION...MAINLY OVER THE NW MTNS TUE AFTERNOON. TODAY WILL BE A
COUPLE OF DEGREES COOLER THAN SATURDAY AS CLOUDS AND SHOWER ACTIVITY
DECREASE THE SOLAR INSULATION. AFTERWARD...TEMPS WILL COOL A FEW
DEGREES MONDAY BEFORE WARMING BACK UP TUESDAY.

.LONG TERM...WEDNESDAY THROUGH SUNDAY

HIGH LATITUDE ENERGY CURRENTLY OVER AK AND THE BERING SEA AREA WILL
DIVE SWD INTO OUR PACNW TROUGH AS UPSTREAM ENERGY...TYPHOON
REMNANTS...PUMPS UP THE UPSTREAM RIDGE OVER THE ERN PACIFIC. THE
END RESULT IS A DEEPENING COLD EARLY SEPTEMBER TROUGH OVER THE
PACNW AND INTERMOUNTAIN WEST THE SECOND HALF OF NEXT WEEK THAT
GRADUALLY TRANSLATES EWD AS THE FLOW DEAMPLIFYS TOWARDS THE END OF
THE PERIOD AND POSSIBLE SPLIT DEVELOPS OVER THE WEST EARLY NEXT
WEEK. THE MIDWEEK PERIOD WILL GENERALLY BE DRY AND QUITE WARM WITH
BREEZY TO LOCALLY WINDY PERIODS AND VERY LIMITED MAINLY MTN TSTMS
CHANCES AT BEST. BY FRIDAY...THE FIRST SIGNIFICANT SHORTWAVE OUT
AHEAD OF THE TROUGH IS ALREADY IMPACTING THE WEST AND NORTH AS A
COLD FRONT TRIES TO SAG SWD INTO THE NRN ZONES. THIS FRONTAL
BOUNDARY WILL BE A SIGNIFICANT PLAYER THROUGH THE WEEKEND WITH
CONSIDERABLY COOLER IF NOT COLDER WEATHER BEHIND IT AS THE MAIN
TROUGH OPENS UP AND PASSES ACROSS NRN WYO AND MONTANA OVER THE
LABOR DAY WEEKEND. A GOOD CHANCE OF SHOWERS AND TSTMS SHOULD OCCUR
IN AT LEAST THE NWRN SECTIONS WITH THIS FIRST SHORTWAVE AND THEN
MORE OF THE WEST AND NORTH AS THE DYNAMICS INTERACT/OVERRUN THE
FRONTAL BOUNDARY OVER THE WEEKEND. DETAILS ARE STILL UNCERTAIN BUT
THE GFS AND ECMWF ARE IN PRETTY GOOD AGREEMENT WITH THE BIG
PICTURE. THE SOURCE REGION OF THIS TROUGH IS QUITE COLD AND MODEL
GUIDANCE IS DROPPING H7 TEMPS DOWN TO AROUND ZERO TO EVEN BELOW
WITH THE FIRST SHORTWAVE FRIDAY NIGHT AND THEN WITH THE MAIN
TROUGH SATURDAY NIGHT SO MOUNTAINS WOULD GET A DECENT SHOT OF SOME
SNOW WITH EACH OF THESE. IT IS LABOR DAY WEEKEND AFTER ALL.

.AVIATION.../18Z ISSUANCE/

A COLD FRONT WILL CONTINUE TO PUSH EAST ACROSS THE INTERMOUNTAIN
WEST TODAY WITH SFC SW FLOW INCREASING ACROSS WEST AND CENTRAL
WYOMING AHEAD OF THE FRONT...ALONG WITH AREAS OF LLWS.  SFC SW WINDS
AT 20-30KTS WILL PREVAIL ACROSS THE AREA INTO THIS AFTERNOON. THE
MAIN AREA ISOLD-SCT -TSRA ARE DEVELOPING VCNTY AND SOUTH OF A
KEVW- KLND- KCPR LINE WITH HIGH BASED WINDY STORMS EXPECTED INTO
THE EARLY EVENING. THE COLD FRONT WILL BRING DRIER AIR AND GUSTY
WEST WIND INTO NW WYOMING MID TO LATE THIS AFTERNOON...PUSHING
ACROSS NORTH AND CENTRAL WYOMING THIS EVENING. CLEAR SKIES AND
DIMINISHING WIND WILL PREVAIL ACROSS THE AREA BEHIND THE FRONT
EARLY MONDAY MORNING.

.FIRE WEATHER...

...RED FLAG WARNING FOR PORTIONS OF CENTRAL AND NORTHERN WYOMING...

OVERALL IT WILL BE WINDIER THAN IT WAS SATURDAY BUT WITH SLIGHTLY
HIGHER RELATIVE HUMIDITY. AS THE COLD FRONT ASSOCIATED WITH THE
TROUGH DIGGING TO THE WEST ADVANCES...IT WILL LIKELY SETTLE INTO
WESTERN...NORTHERN AND SOUTHERN WYOMING FAIRLY EARLY IN THE
DAY...WHICH WOULD END THE FIRE WEATHER THREAT IN THOSE LOCATIONS
ALONG WITH INCREASING CLOUDS AS WELL AS A SLIGHT CHANCE FOR A
WETTING RAIN. STRONG SOUTHWEST FLOW BUT STILL LOW HUMIDITY ACROSS
FREMONT...JOHNSON AND NATRONA COUNTIES WILL OCCUR SO THESE AREAS
WILL CONTINUE TO BE UNDER THE RED FLAG WARNING FOR TODAY. IN
ADDITION...A SWATH OF MID LEVEL MOISTURE AND CONTINUED INSTABILITY
WILL KICK OF A FEW MIXED WET AND DRY THUNDERSTORMS...SOME OF WHICH
COULD CONTRIBUTE TO NEW FIRE STARTS WITH THE MOST ACTIVITY
EXPECTED ACROSS NORTHERN AND WESTERN WYOMING...WITH A SECONDARY
SWATH EXPECTED OVER NATRONA AND EASTERN FREMONT COUNTIES LATE
SUNDAY AFTERNOON...THE CHANCE OF A WETTING RAIN OUT OF THESE
STORMS IS NEXT TO ZERO. THE BEST CHANCE OF ANY DRY LIGHTNING
STARTS WILL LIKELY BE ON THE PERIPHERY OF ANY THUNDERSTORMS THAT
FORM ACROSS NORTHERN WYOMING EAST OF THE DIVIDE THROUGH MID DAY
WHERE THE BEST INSTABILITY WILL BE...THEN FROM EASTERN SWEETWATER
COUNTY TO CASPER AND THE REST OF NATRONA COUNTY LATER IN THE
AFTERNOON WHERE THE COMBINATION OF DRIEST BOUNDARY LEVEL MOISTURE
AND WIDEST TEMP/DEW POINT SPREADS WILL LIE.

A REPEAT OF THESE CONDITIONS WILL BE POSSIBLE MID WEEK.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...
RED FLAG WARNING UNTIL 9 PM MDT THIS EVENING FOR WYZ280-283-285-
289-300.

RED FLAG WARNING UNTIL 3 AM MDT MONDAY FOR WYZ275-276-281-282-
287.

&&

$$

SHORT TERM...LIPSON
LONG TERM...SKRBAC
AVIATION...ALLEN
FIRE WEATHER...LIPSON




000
FXUS65 KRIW 301747 AAA
AFDRIW

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE RIVERTON WY
1147 AM MDT SUN AUG 30 2015

.PREV DISCUSSION... /ISSUED 250 AM MDT SUN AUG 30 2015/

.SHORT TERM...TODAY THROUGH TUESDAY NIGHT

A STRONG TROUGH OF LOW PRESSURE JUST OFF THE PACIFIC NORTHWEST COAST
HAS EJECTED A SHEARED UPPER LEVEL SHORTWAVE EASTWARD THAT APPEARS TO
BE LOCATED OVER NORTHERN IDAHO AND WESTERN MT. ACTIVE CONVECTION
CONTINUES OUT AHEAD OF THIS FEATURE ACROSS EASTERN IDAHO NEAR THE
WYOMING BORDER AND INTO YNP AT THE TIME OF THIS WRITING. IT WILL BE
AN EARLY SHOW FOR CONVECTION IN WESTERN WY TODAY WITH THESE STORMS
ABOUT TO SWEEP ACROSS FAR WEST WYOMING DURING THE REMAINDER OF THE
NIGHT. THEN THE MAIN TROUGH WILL APPROACH THE NORTHERN ROCKIES TODAY
FOR ANOTHER ROUND OF CONVECTION FIRING UP IN FAR WESTERN WY BY MID
DAY AHEAD OF THE MAIN TROUGH AND ASCT COLD FRONT. IN THE
MEANTIME...EAST OF THE DIVIDE...SOUTHWEST WINDS WILL INCREASE OVER
WHAT THEY WERE SATURDAY AS THEY DRAW IN SLIGHTLY HIGHER LOWER LEVEL
MOISTURE. INSTABILITY WILL BE IN PLACE OVER THE ENTIRE CWA BUT ONLY
SCANT MOISTURE TO WORK WITH TO PRODUCE THUNDERSTORMS EAST OF THE
DIVIDE...AT LEAST INITIALLY IN THE EARLY TO MID AFTERNOON. THERE
WILL BE A SEPARATE FINGER OF WEAK HIGH AND MID LEVEL MONSOON
MOISTURE THAT WILL STREAM IN ACROSS RKS AND CPR. HOWEVER THE BEST
INSTABILITY WILL BE IN PLACE ACROSS NORTHERN WY WHERE THE BEST CAPES
WILL BE. IT APPEARS THE BEST CHANCE OF ANY DRY LIGHTNING WILL OCCUR
ON THE PERIPHERY OF ANY HIGH BASED THUNDERSTORMS ALONG THE
AFOREMENTIONED WEAK MONSOON MOISTURE PLUME AS WELL AS ACROSS
NORTHERN WY EAST OF THE DIVIDE WHERE RELATIVELY HIGH BASED STORMS
WILL CORRELATE WITH THE BEST CAPES. DRY THUNDERSTORMS WILL MORPH
INTO MORE WET STORMS AS THE FRONT DRAWS NEAR. THE TROUGHPA WILL
SWEEP ACROSS THE CWA TONIGHT. THEN ON MONDAY...ANOTHER SURGE OF WEAK
MID/UPPER LEVEL MOISTURE WILL OVERLAP SOME LINGERING INSTABILITY
OVER EXTREME SOUTHERN WY WHERE SOME ISOLD T STORMS ARE EXPECTED.
THEN BY TUESDAY...ANOTHER CLOSED LOW WILL ESTABLISH ITSELF ALONG THE
SOUTHERN BC COAST. THIS LOW WILL EJECT A WEAK VORT LOBE EAST
NORTHEAST ACROSS THE NORTHERN ROCKIES THAT WILL RESULT IN ISOLD
CONVECTION...MAINLY OVER THE NW MTNS TUE AFTERNOON. TODAY WILL BE A
COUPLE OF DEGREES COOLER THAN SATURDAY AS CLOUDS AND SHOWER ACTIVITY
DECREASE THE SOLAR INSULATION. AFTERWARD...TEMPS WILL COOL A FEW
DEGREES MONDAY BEFORE WARMING BACK UP TUESDAY.

.LONG TERM...WEDNESDAY THROUGH SUNDAY

HIGH LATITUDE ENERGY CURRENTLY OVER AK AND THE BERING SEA AREA WILL
DIVE SWD INTO OUR PACNW TROUGH AS UPSTREAM ENERGY...TYPHOON
REMNANTS...PUMPS UP THE UPSTREAM RIDGE OVER THE ERN PACIFIC. THE
END RESULT IS A DEEPENING COLD EARLY SEPTEMBER TROUGH OVER THE
PACNW AND INTERMOUNTAIN WEST THE SECOND HALF OF NEXT WEEK THAT
GRADUALLY TRANSLATES EWD AS THE FLOW DEAMPLIFYS TOWARDS THE END OF
THE PERIOD AND POSSIBLE SPLIT DEVELOPS OVER THE WEST EARLY NEXT
WEEK. THE MIDWEEK PERIOD WILL GENERALLY BE DRY AND QUITE WARM WITH
BREEZY TO LOCALLY WINDY PERIODS AND VERY LIMITED MAINLY MTN TSTMS
CHANCES AT BEST. BY FRIDAY...THE FIRST SIGNIFICANT SHORTWAVE OUT
AHEAD OF THE TROUGH IS ALREADY IMPACTING THE WEST AND NORTH AS A
COLD FRONT TRIES TO SAG SWD INTO THE NRN ZONES. THIS FRONTAL
BOUNDARY WILL BE A SIGNIFICANT PLAYER THROUGH THE WEEKEND WITH
CONSIDERABLY COOLER IF NOT COLDER WEATHER BEHIND IT AS THE MAIN
TROUGH OPENS UP AND PASSES ACROSS NRN WYO AND MONTANA OVER THE
LABOR DAY WEEKEND. A GOOD CHANCE OF SHOWERS AND TSTMS SHOULD OCCUR
IN AT LEAST THE NWRN SECTIONS WITH THIS FIRST SHORTWAVE AND THEN
MORE OF THE WEST AND NORTH AS THE DYNAMICS INTERACT/OVERRUN THE
FRONTAL BOUNDARY OVER THE WEEKEND. DETAILS ARE STILL UNCERTAIN BUT
THE GFS AND ECMWF ARE IN PRETTY GOOD AGREEMENT WITH THE BIG
PICTURE. THE SOURCE REGION OF THIS TROUGH IS QUITE COLD AND MODEL
GUIDANCE IS DROPPING H7 TEMPS DOWN TO AROUND ZERO TO EVEN BELOW
WITH THE FIRST SHORTWAVE FRIDAY NIGHT AND THEN WITH THE MAIN
TROUGH SATURDAY NIGHT SO MOUNTAINS WOULD GET A DECENT SHOT OF SOME
SNOW WITH EACH OF THESE. IT IS LABOR DAY WEEKEND AFTER ALL.

.AVIATION.../18Z ISSUANCE/

A COLD FRONT WILL CONTINUE TO PUSH EAST ACROSS THE INTERMOUNTAIN
WEST TODAY WITH SFC SW FLOW INCREASING ACROSS WEST AND CENTRAL
WYOMING AHEAD OF THE FRONT...ALONG WITH AREAS OF LLWS.  SFC SW WINDS
AT 20-30KTS WILL PREVAIL ACROSS THE AREA INTO THIS AFTERNOON. THE
MAIN AREA ISOLD-SCT -TSRA ARE DEVELOPING VCNTY AND SOUTH OF A
KEVW- KLND- KCPR LINE WITH HIGH BASED WINDY STORMS EXPECTED INTO
THE EARLY EVENING. THE COLD FRONT WILL BRING DRIER AIR AND GUSTY
WEST WIND INTO NW WYOMING MID TO LATE THIS AFTERNOON...PUSHING
ACROSS NORTH AND CENTRAL WYOMING THIS EVENING. CLEAR SKIES AND
DIMINISHING WIND WILL PREVAIL ACROSS THE AREA BEHIND THE FRONT
EARLY MONDAY MORNING.

.FIRE WEATHER...

...RED FLAG WARNING FOR PORTIONS OF CENTRAL AND NORTHERN WYOMING...

OVERALL IT WILL BE WINDIER THAN IT WAS SATURDAY BUT WITH SLIGHTLY
HIGHER RELATIVE HUMIDITY. AS THE COLD FRONT ASSOCIATED WITH THE
TROUGH DIGGING TO THE WEST ADVANCES...IT WILL LIKELY SETTLE INTO
WESTERN...NORTHERN AND SOUTHERN WYOMING FAIRLY EARLY IN THE
DAY...WHICH WOULD END THE FIRE WEATHER THREAT IN THOSE LOCATIONS
ALONG WITH INCREASING CLOUDS AS WELL AS A SLIGHT CHANCE FOR A
WETTING RAIN. STRONG SOUTHWEST FLOW BUT STILL LOW HUMIDITY ACROSS
FREMONT...JOHNSON AND NATRONA COUNTIES WILL OCCUR SO THESE AREAS
WILL CONTINUE TO BE UNDER THE RED FLAG WARNING FOR TODAY. IN
ADDITION...A SWATH OF MID LEVEL MOISTURE AND CONTINUED INSTABILITY
WILL KICK OF A FEW MIXED WET AND DRY THUNDERSTORMS...SOME OF WHICH
COULD CONTRIBUTE TO NEW FIRE STARTS WITH THE MOST ACTIVITY
EXPECTED ACROSS NORTHERN AND WESTERN WYOMING...WITH A SECONDARY
SWATH EXPECTED OVER NATRONA AND EASTERN FREMONT COUNTIES LATE
SUNDAY AFTERNOON...THE CHANCE OF A WETTING RAIN OUT OF THESE
STORMS IS NEXT TO ZERO. THE BEST CHANCE OF ANY DRY LIGHTNING
STARTS WILL LIKELY BE ON THE PERIPHERY OF ANY THUNDERSTORMS THAT
FORM ACROSS NORTHERN WYOMING EAST OF THE DIVIDE THROUGH MID DAY
WHERE THE BEST INSTABILITY WILL BE...THEN FROM EASTERN SWEETWATER
COUNTY TO CASPER AND THE REST OF NATRONA COUNTY LATER IN THE
AFTERNOON WHERE THE COMBINATION OF DRIEST BOUNDARY LEVEL MOISTURE
AND WIDEST TEMP/DEW POINT SPREADS WILL LIE.

A REPEAT OF THESE CONDITIONS WILL BE POSSIBLE MID WEEK.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...
RED FLAG WARNING UNTIL 9 PM MDT THIS EVENING FOR WYZ280-283-285-
289-300.

RED FLAG WARNING UNTIL 3 AM MDT MONDAY FOR WYZ275-276-281-282-
287.

&&

$$

SHORT TERM...LIPSON
LONG TERM...SKRBAC
AVIATION...ALLEN
FIRE WEATHER...LIPSON




000
FXUS65 KRIW 301747 AAA
AFDRIW

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE RIVERTON WY
1147 AM MDT SUN AUG 30 2015

.PREV DISCUSSION... /ISSUED 250 AM MDT SUN AUG 30 2015/

.SHORT TERM...TODAY THROUGH TUESDAY NIGHT

A STRONG TROUGH OF LOW PRESSURE JUST OFF THE PACIFIC NORTHWEST COAST
HAS EJECTED A SHEARED UPPER LEVEL SHORTWAVE EASTWARD THAT APPEARS TO
BE LOCATED OVER NORTHERN IDAHO AND WESTERN MT. ACTIVE CONVECTION
CONTINUES OUT AHEAD OF THIS FEATURE ACROSS EASTERN IDAHO NEAR THE
WYOMING BORDER AND INTO YNP AT THE TIME OF THIS WRITING. IT WILL BE
AN EARLY SHOW FOR CONVECTION IN WESTERN WY TODAY WITH THESE STORMS
ABOUT TO SWEEP ACROSS FAR WEST WYOMING DURING THE REMAINDER OF THE
NIGHT. THEN THE MAIN TROUGH WILL APPROACH THE NORTHERN ROCKIES TODAY
FOR ANOTHER ROUND OF CONVECTION FIRING UP IN FAR WESTERN WY BY MID
DAY AHEAD OF THE MAIN TROUGH AND ASCT COLD FRONT. IN THE
MEANTIME...EAST OF THE DIVIDE...SOUTHWEST WINDS WILL INCREASE OVER
WHAT THEY WERE SATURDAY AS THEY DRAW IN SLIGHTLY HIGHER LOWER LEVEL
MOISTURE. INSTABILITY WILL BE IN PLACE OVER THE ENTIRE CWA BUT ONLY
SCANT MOISTURE TO WORK WITH TO PRODUCE THUNDERSTORMS EAST OF THE
DIVIDE...AT LEAST INITIALLY IN THE EARLY TO MID AFTERNOON. THERE
WILL BE A SEPARATE FINGER OF WEAK HIGH AND MID LEVEL MONSOON
MOISTURE THAT WILL STREAM IN ACROSS RKS AND CPR. HOWEVER THE BEST
INSTABILITY WILL BE IN PLACE ACROSS NORTHERN WY WHERE THE BEST CAPES
WILL BE. IT APPEARS THE BEST CHANCE OF ANY DRY LIGHTNING WILL OCCUR
ON THE PERIPHERY OF ANY HIGH BASED THUNDERSTORMS ALONG THE
AFOREMENTIONED WEAK MONSOON MOISTURE PLUME AS WELL AS ACROSS
NORTHERN WY EAST OF THE DIVIDE WHERE RELATIVELY HIGH BASED STORMS
WILL CORRELATE WITH THE BEST CAPES. DRY THUNDERSTORMS WILL MORPH
INTO MORE WET STORMS AS THE FRONT DRAWS NEAR. THE TROUGHPA WILL
SWEEP ACROSS THE CWA TONIGHT. THEN ON MONDAY...ANOTHER SURGE OF WEAK
MID/UPPER LEVEL MOISTURE WILL OVERLAP SOME LINGERING INSTABILITY
OVER EXTREME SOUTHERN WY WHERE SOME ISOLD T STORMS ARE EXPECTED.
THEN BY TUESDAY...ANOTHER CLOSED LOW WILL ESTABLISH ITSELF ALONG THE
SOUTHERN BC COAST. THIS LOW WILL EJECT A WEAK VORT LOBE EAST
NORTHEAST ACROSS THE NORTHERN ROCKIES THAT WILL RESULT IN ISOLD
CONVECTION...MAINLY OVER THE NW MTNS TUE AFTERNOON. TODAY WILL BE A
COUPLE OF DEGREES COOLER THAN SATURDAY AS CLOUDS AND SHOWER ACTIVITY
DECREASE THE SOLAR INSULATION. AFTERWARD...TEMPS WILL COOL A FEW
DEGREES MONDAY BEFORE WARMING BACK UP TUESDAY.

.LONG TERM...WEDNESDAY THROUGH SUNDAY

HIGH LATITUDE ENERGY CURRENTLY OVER AK AND THE BERING SEA AREA WILL
DIVE SWD INTO OUR PACNW TROUGH AS UPSTREAM ENERGY...TYPHOON
REMNANTS...PUMPS UP THE UPSTREAM RIDGE OVER THE ERN PACIFIC. THE
END RESULT IS A DEEPENING COLD EARLY SEPTEMBER TROUGH OVER THE
PACNW AND INTERMOUNTAIN WEST THE SECOND HALF OF NEXT WEEK THAT
GRADUALLY TRANSLATES EWD AS THE FLOW DEAMPLIFYS TOWARDS THE END OF
THE PERIOD AND POSSIBLE SPLIT DEVELOPS OVER THE WEST EARLY NEXT
WEEK. THE MIDWEEK PERIOD WILL GENERALLY BE DRY AND QUITE WARM WITH
BREEZY TO LOCALLY WINDY PERIODS AND VERY LIMITED MAINLY MTN TSTMS
CHANCES AT BEST. BY FRIDAY...THE FIRST SIGNIFICANT SHORTWAVE OUT
AHEAD OF THE TROUGH IS ALREADY IMPACTING THE WEST AND NORTH AS A
COLD FRONT TRIES TO SAG SWD INTO THE NRN ZONES. THIS FRONTAL
BOUNDARY WILL BE A SIGNIFICANT PLAYER THROUGH THE WEEKEND WITH
CONSIDERABLY COOLER IF NOT COLDER WEATHER BEHIND IT AS THE MAIN
TROUGH OPENS UP AND PASSES ACROSS NRN WYO AND MONTANA OVER THE
LABOR DAY WEEKEND. A GOOD CHANCE OF SHOWERS AND TSTMS SHOULD OCCUR
IN AT LEAST THE NWRN SECTIONS WITH THIS FIRST SHORTWAVE AND THEN
MORE OF THE WEST AND NORTH AS THE DYNAMICS INTERACT/OVERRUN THE
FRONTAL BOUNDARY OVER THE WEEKEND. DETAILS ARE STILL UNCERTAIN BUT
THE GFS AND ECMWF ARE IN PRETTY GOOD AGREEMENT WITH THE BIG
PICTURE. THE SOURCE REGION OF THIS TROUGH IS QUITE COLD AND MODEL
GUIDANCE IS DROPPING H7 TEMPS DOWN TO AROUND ZERO TO EVEN BELOW
WITH THE FIRST SHORTWAVE FRIDAY NIGHT AND THEN WITH THE MAIN
TROUGH SATURDAY NIGHT SO MOUNTAINS WOULD GET A DECENT SHOT OF SOME
SNOW WITH EACH OF THESE. IT IS LABOR DAY WEEKEND AFTER ALL.

.AVIATION.../18Z ISSUANCE/

A COLD FRONT WILL CONTINUE TO PUSH EAST ACROSS THE INTERMOUNTAIN
WEST TODAY WITH SFC SW FLOW INCREASING ACROSS WEST AND CENTRAL
WYOMING AHEAD OF THE FRONT...ALONG WITH AREAS OF LLWS.  SFC SW WINDS
AT 20-30KTS WILL PREVAIL ACROSS THE AREA INTO THIS AFTERNOON. THE
MAIN AREA ISOLD-SCT -TSRA ARE DEVELOPING VCNTY AND SOUTH OF A
KEVW- KLND- KCPR LINE WITH HIGH BASED WINDY STORMS EXPECTED INTO
THE EARLY EVENING. THE COLD FRONT WILL BRING DRIER AIR AND GUSTY
WEST WIND INTO NW WYOMING MID TO LATE THIS AFTERNOON...PUSHING
ACROSS NORTH AND CENTRAL WYOMING THIS EVENING. CLEAR SKIES AND
DIMINISHING WIND WILL PREVAIL ACROSS THE AREA BEHIND THE FRONT
EARLY MONDAY MORNING.

.FIRE WEATHER...

...RED FLAG WARNING FOR PORTIONS OF CENTRAL AND NORTHERN WYOMING...

OVERALL IT WILL BE WINDIER THAN IT WAS SATURDAY BUT WITH SLIGHTLY
HIGHER RELATIVE HUMIDITY. AS THE COLD FRONT ASSOCIATED WITH THE
TROUGH DIGGING TO THE WEST ADVANCES...IT WILL LIKELY SETTLE INTO
WESTERN...NORTHERN AND SOUTHERN WYOMING FAIRLY EARLY IN THE
DAY...WHICH WOULD END THE FIRE WEATHER THREAT IN THOSE LOCATIONS
ALONG WITH INCREASING CLOUDS AS WELL AS A SLIGHT CHANCE FOR A
WETTING RAIN. STRONG SOUTHWEST FLOW BUT STILL LOW HUMIDITY ACROSS
FREMONT...JOHNSON AND NATRONA COUNTIES WILL OCCUR SO THESE AREAS
WILL CONTINUE TO BE UNDER THE RED FLAG WARNING FOR TODAY. IN
ADDITION...A SWATH OF MID LEVEL MOISTURE AND CONTINUED INSTABILITY
WILL KICK OF A FEW MIXED WET AND DRY THUNDERSTORMS...SOME OF WHICH
COULD CONTRIBUTE TO NEW FIRE STARTS WITH THE MOST ACTIVITY
EXPECTED ACROSS NORTHERN AND WESTERN WYOMING...WITH A SECONDARY
SWATH EXPECTED OVER NATRONA AND EASTERN FREMONT COUNTIES LATE
SUNDAY AFTERNOON...THE CHANCE OF A WETTING RAIN OUT OF THESE
STORMS IS NEXT TO ZERO. THE BEST CHANCE OF ANY DRY LIGHTNING
STARTS WILL LIKELY BE ON THE PERIPHERY OF ANY THUNDERSTORMS THAT
FORM ACROSS NORTHERN WYOMING EAST OF THE DIVIDE THROUGH MID DAY
WHERE THE BEST INSTABILITY WILL BE...THEN FROM EASTERN SWEETWATER
COUNTY TO CASPER AND THE REST OF NATRONA COUNTY LATER IN THE
AFTERNOON WHERE THE COMBINATION OF DRIEST BOUNDARY LEVEL MOISTURE
AND WIDEST TEMP/DEW POINT SPREADS WILL LIE.

A REPEAT OF THESE CONDITIONS WILL BE POSSIBLE MID WEEK.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...
RED FLAG WARNING UNTIL 9 PM MDT THIS EVENING FOR WYZ280-283-285-
289-300.

RED FLAG WARNING UNTIL 3 AM MDT MONDAY FOR WYZ275-276-281-282-
287.

&&

$$

SHORT TERM...LIPSON
LONG TERM...SKRBAC
AVIATION...ALLEN
FIRE WEATHER...LIPSON



000
FXUS65 KCYS 301734
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
1134 AM MDT SUN AUG 30 2015

.UPDATE...
ISSUED AT 941 AM MDT SUN AUG 30 2015

MOSAIC RADAR IS SHOWING SHOWER ACTIVITY DEVELOPING ACROSS FAR
NORTHEAST UTAH AND FAR NORTHWEST COLORADO. ALSO A FEW SHOWERS NOW
SHOWING UP IN SOUTHCENTRAL WYOMING. THIS ACTIVITY WILL SPREAD EAST
ACROSS SOUTHEAST WYOMING THIS AFTERNOON ALONG WITH ISOLATED
THUNDERSTORMS. COOLING MID LEVELS OF THE ATMOSPHERE AND MID LEVEL
CONVERGENCE ASSOCIATED WITH SHORTWAVE TROUGH WILL BE A BIG FACTOR
IN SHOWERS AND THUNDERSTORMS...AS WELL AS THE RIGHT ENTRANCE
REGION OF THE UPPER LEVEL JET. THERE THREAT FOR SEVERE
THUNDERSTORMS IS LOW BUT WITH LARGE TEMPERATURE DEW POINT SPREADS
AND TYPICAL LATE AUGUST INVERTED V SOUNDING PROFILES...STRONG
WIND GUSTS WILL BE POSSIBLE WITH GUSTS TO AROUND 60 MPH NOT
COMPLETELY OUT OF THE QUESTION.

&&

.SHORT TERM...(TODAY THROUGH TUESDAY NIGHT)
ISSUED AT 405 AM MDT SUN AUG 30 2015

SOME HIGH CLOUDS ARE MOVING OVERHEAD EARLY THIS MORNING WITH SOUTH-
SOUTHWEST WINDS ON AVERAGE OF 5 TO 15 MPH OBSERVED AT MANY
LOCATIONS. THE NEAR SFC INVERSION SEEMS TO BE STRONG ENOUGH TO KEEP
THE GUSTY LLVL JET WINDS AT BAY THO SO SHOULD SEE THESE LIGHTER
WINDS PERSIST THRU THE MORNING.

THE LEESIDE PRESSURE TROUGH WILL DEEPEN THIS MORNING AS A STRONG
UPPER LEVEL SHORTWAVE MOVES ACROSS THE PAC NW AND NORTHERN
ROCKIES TODAY. WEST-SOUTHWEST SFC WINDS ARE EXPECTED TO INCREASE
AS THIS OCCURS AND AS THE INVERSION BEGINS TO LIFT AFTER SUNRISE.
FORECAST SOUNDS SHOW A DEEP MIXED LAYER UP TO ROUGHLY 550 MB BY
THIS AFTERNOON...WITH WINDS THRU THE MIXED LAYER MAXING OUT AT 20
TO 25 KTS OVER THE MOUNTAINS AND EAST CENTRAL WYOMING...AND 10 TO
15 KTS TO THE LEE OF THE LARAMIE RANGE AND POINTS EAST.
THEREFORE...EXPECT GUSTY WINDS TO PERSIST THRU THE AFTERNOON
WITHIN A CORRIDOR FROM CARBON COUNTY TO CONVERSE/NIOBRARA COUNTIES
WHILE WINDS SHOULD DIMINISH WITHIN THE DEEPENING LEESIDE TROUGH
ACROSS EXTREME SOUTHEAST WYOMING AND THE WESTERN NEBRASKA
PANHANDLE. HOT TEMPS WILL OCCUR TODAY WITH 80S AND 90S ACROSS
SOUTHEAST WYOMING AND 90S AND PERHAPS A FEW 100 DEGREE READINGS
IN THE PANHANDLE WITH THE THERMAL RIDGE OVERHEAD. A FETCH OF
SUBTROPICAL MOISTURE WILL ADVECT UP AND INTO THE CWA TODAY AS WELL
AND WILL KEEP HUMIDITIES IN THE UPPER TEENS TO LOW 20S ALONG AND
WEST OF THE LARAMIE RANGE WITH MID TO UPPER TEENS ACROSS THE
PLAINS. STILL LOOKING AT THE BEST JUXTAPOSITION OF LOW HUMIDITIES
AND GUSTY WINDS EARLY THIS AFTERNOON ACROSS FWZ 301 SO WILL KEEP
THE RED FLAG WARNING IN PLACE HERE. WINDS SHOULD BE ON THE
DOWNWARD TURN FURTHER SOUTH AND EAST WHEN HUMIDITIES WILL BE AT
THEIR LOWEST SO LOOKING AT ONLY MARGINAL FIRE WEATHER CONCERNS
HERE FOR ZONES 309 AND 310.

SHOWERS AND ISOLATED TSTMS WILL DEVELOP OVER THE MOUNTAINS THIS
AFTERNOON WITHIN THE DEEPEST MOISTURE AND AS WINDS ALOFT INCREASE
WITH THE APPROACHING SHORTWAVE. STILL THINKING SOME OF THIS
ACTIVITY WILL SHIFT TO THE PLAINS THRU THE LATE AFTERNOON AND
EVENING AS THE MOISTURE PLUME CONTINUES TO OVERSPREAD THE CWA.
GUIDANCE CONTINUES TO SHOW ENOUGH MOISTURE TO PRODUCE MODEST
RAINFALL WITH MUCH OF THE ACTIVITY...AND INVERTED-V PROFILES
SUGGEST GUSTY AND ERRATIC WINDS ARE A HIGH LIKELIHOOD AS WELL.

WINDS TONIGHT COULD REMAIN A BIT BREEZY AHEAD OF THE COLD FRONT
THAT IS STILL PROGGED TO DROP SOUTH ACROSS THE REGION STARTING
AROUND SUNRISE ON MONDAY. COOLER TEMPS ARE EXPECTED FOR MONDAY
WITH INCREASING MOISTURE AND UPSLOPE FLOW PROGGED THRU THE
AFTERNOON ACROSS THE PLAINS. A WEAK DISTURBANCE MOVING OVERHEAD IN
SOUTHWEST FLOW SHOULD SPARK OFF MORE AFTERNOON TSTMS IN THE HIGH
COUNTRY AIDED BY STRENGTHENING UPSLOPE FLOW. ADDITIONAL WEAK
VORTICITY AND MOISTURE MOVING OVERHEAD ON THE NOSE OF A JETLET
APPROACHING FROM THE SOUTHWEST ON TUESDAY WILL BRING ANOTHER
ROUND OF SHOWERS/TSTMS TO THE CWA IN THE AFTERNOON.

.LONG TERM...(WEDNESDAY THROUGH SATURDAY)
ISSUED AT 405 AM MDT SUN AUG 30 2015

WE REMAIN UNDER A BROAD SOUTHWESTERLY FLOW ALOFT WEDNESDAY THROUGH
LATE WEEK AS A AMPLIFYING UPPER TROUGH OVER THE PACIFIC NORTHWEST
STARTS TO MOVE EASTWARD. WITH FAIRLY DRY DEEP LAYERED AIRMASS WE
SHOULD SEE LITTLE IN THE WAY OF POPS EXCEPT FOR MAYBE A FEW
ISOLATED AFTERNOON/EVENING STORMS IN THE MOUNTAINS OF SE
WYOMING...MAINLY ON WEDNESDAY. BY THE WEEKEND WE WILL SEE SEVERAL
STRONGER MIDLEVEL IMPULSES MOVE THROUGH THE INCREASING
SOUTHWESTERLY FLOW ALOFT AS THE UPPER TROUGH TO THE NORTHWEST
STARTS TO EJECT OUT TO THE EAST...AND THIS IS EXPECTED TO BRING A
WEAK COLD FRONT DOWN FROM THE NORTHWEST HANGING IT UP ALONG THE
LARAMIE RANGE ON SATURDAY. THIS MAY FOCUS SOME ISOLATED TO
SCATTERED AFTERNOON/EVENING THUNDERSTORMS OVER THE EASTERN HALF OF
THE FORECAST AREA SATURDAY AFTERNOON AND EVENING.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1120 AM MDT SUN AUG 30 2015

SCATTERED THUNDERSTORMS THIS AFTERNOON...FOR RAWLINS AND LARAMIE
AS AN UPPER LEVEL DISTURBANCE MOVES ACROSS THE FORECAST AREA.
CHEYENNE COULD SEE SOME ISOLATED SHOWERS LATER INTO THE NIGHT.
BRIEF MVFR CONDITIONS CAN BE SEEN WITH A PASSING THUNDERSTORM.
OTHERWISE EXPECT VFR CONDITIONS THROUGHOUT THE DAY. WINDS ARE
EXPECTED TO PICK UP THROUGHOUT THE AFTERNOON HOURS FOR THE
NEBRASKA PANHANDLE. OVERNIGHT WINDS WILL CONTINUE TO BE GUSTY FOR
CHADRON WITH THE DEVELOPMENT OF A LLVL JET.

&&

.FIRE WEATHER...
ISSUED AT 405 AM MDT SUN AUG 30 2015

HOT AND RELATIVELY DRY CONDITIONS ARE EXPECTED TODAY OVER MUCH OF
THE DISTRICT...WITH BREEZY WINDS THIS MORNING CONTINUING THROUGH
THE AFTERNOON IN THE HIGH COUNTRY AND FOR CONVERSE/NIOBRARA
COUNTIES. WINDS LOOK TO DIMINISH ALONG AND EAST OF THE LARAMIE
RANGE AFTER NOON TODAY. THE RED FLAG WARNING REMAINS IN EFFECT
FOR FWZ 301 FOR THE COMBINATION OF DRY AND BREEZY CONDITIONS.
INCREASING MOISTURE LATER THIS MORNING AND AFTERNOON WILL GIVE
CHANCES FOR WETTING RAINS MAINLY OVER THE MOUNTAINS AND PLAINS OF
SOUTHEAST WYOMING. CHANCES FOR RAIN WILL CONTINUE OVER THE
MOUNTAINS AND SOUTHERN WYO PLAINS THRU TUESDAY.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...RED FLAG WARNING UNTIL 7 PM MDT THIS EVENING FOR WYZ301.

NE...NONE.
&&

$$

UPDATE...SML
SHORT TERM...RJM
LONG TERM...JG
AVIATION...GCC/KC
FIRE WEATHER...RJM




000
FXUS65 KCYS 301734
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
1134 AM MDT SUN AUG 30 2015

.UPDATE...
ISSUED AT 941 AM MDT SUN AUG 30 2015

MOSAIC RADAR IS SHOWING SHOWER ACTIVITY DEVELOPING ACROSS FAR
NORTHEAST UTAH AND FAR NORTHWEST COLORADO. ALSO A FEW SHOWERS NOW
SHOWING UP IN SOUTHCENTRAL WYOMING. THIS ACTIVITY WILL SPREAD EAST
ACROSS SOUTHEAST WYOMING THIS AFTERNOON ALONG WITH ISOLATED
THUNDERSTORMS. COOLING MID LEVELS OF THE ATMOSPHERE AND MID LEVEL
CONVERGENCE ASSOCIATED WITH SHORTWAVE TROUGH WILL BE A BIG FACTOR
IN SHOWERS AND THUNDERSTORMS...AS WELL AS THE RIGHT ENTRANCE
REGION OF THE UPPER LEVEL JET. THERE THREAT FOR SEVERE
THUNDERSTORMS IS LOW BUT WITH LARGE TEMPERATURE DEW POINT SPREADS
AND TYPICAL LATE AUGUST INVERTED V SOUNDING PROFILES...STRONG
WIND GUSTS WILL BE POSSIBLE WITH GUSTS TO AROUND 60 MPH NOT
COMPLETELY OUT OF THE QUESTION.

&&

.SHORT TERM...(TODAY THROUGH TUESDAY NIGHT)
ISSUED AT 405 AM MDT SUN AUG 30 2015

SOME HIGH CLOUDS ARE MOVING OVERHEAD EARLY THIS MORNING WITH SOUTH-
SOUTHWEST WINDS ON AVERAGE OF 5 TO 15 MPH OBSERVED AT MANY
LOCATIONS. THE NEAR SFC INVERSION SEEMS TO BE STRONG ENOUGH TO KEEP
THE GUSTY LLVL JET WINDS AT BAY THO SO SHOULD SEE THESE LIGHTER
WINDS PERSIST THRU THE MORNING.

THE LEESIDE PRESSURE TROUGH WILL DEEPEN THIS MORNING AS A STRONG
UPPER LEVEL SHORTWAVE MOVES ACROSS THE PAC NW AND NORTHERN
ROCKIES TODAY. WEST-SOUTHWEST SFC WINDS ARE EXPECTED TO INCREASE
AS THIS OCCURS AND AS THE INVERSION BEGINS TO LIFT AFTER SUNRISE.
FORECAST SOUNDS SHOW A DEEP MIXED LAYER UP TO ROUGHLY 550 MB BY
THIS AFTERNOON...WITH WINDS THRU THE MIXED LAYER MAXING OUT AT 20
TO 25 KTS OVER THE MOUNTAINS AND EAST CENTRAL WYOMING...AND 10 TO
15 KTS TO THE LEE OF THE LARAMIE RANGE AND POINTS EAST.
THEREFORE...EXPECT GUSTY WINDS TO PERSIST THRU THE AFTERNOON
WITHIN A CORRIDOR FROM CARBON COUNTY TO CONVERSE/NIOBRARA COUNTIES
WHILE WINDS SHOULD DIMINISH WITHIN THE DEEPENING LEESIDE TROUGH
ACROSS EXTREME SOUTHEAST WYOMING AND THE WESTERN NEBRASKA
PANHANDLE. HOT TEMPS WILL OCCUR TODAY WITH 80S AND 90S ACROSS
SOUTHEAST WYOMING AND 90S AND PERHAPS A FEW 100 DEGREE READINGS
IN THE PANHANDLE WITH THE THERMAL RIDGE OVERHEAD. A FETCH OF
SUBTROPICAL MOISTURE WILL ADVECT UP AND INTO THE CWA TODAY AS WELL
AND WILL KEEP HUMIDITIES IN THE UPPER TEENS TO LOW 20S ALONG AND
WEST OF THE LARAMIE RANGE WITH MID TO UPPER TEENS ACROSS THE
PLAINS. STILL LOOKING AT THE BEST JUXTAPOSITION OF LOW HUMIDITIES
AND GUSTY WINDS EARLY THIS AFTERNOON ACROSS FWZ 301 SO WILL KEEP
THE RED FLAG WARNING IN PLACE HERE. WINDS SHOULD BE ON THE
DOWNWARD TURN FURTHER SOUTH AND EAST WHEN HUMIDITIES WILL BE AT
THEIR LOWEST SO LOOKING AT ONLY MARGINAL FIRE WEATHER CONCERNS
HERE FOR ZONES 309 AND 310.

SHOWERS AND ISOLATED TSTMS WILL DEVELOP OVER THE MOUNTAINS THIS
AFTERNOON WITHIN THE DEEPEST MOISTURE AND AS WINDS ALOFT INCREASE
WITH THE APPROACHING SHORTWAVE. STILL THINKING SOME OF THIS
ACTIVITY WILL SHIFT TO THE PLAINS THRU THE LATE AFTERNOON AND
EVENING AS THE MOISTURE PLUME CONTINUES TO OVERSPREAD THE CWA.
GUIDANCE CONTINUES TO SHOW ENOUGH MOISTURE TO PRODUCE MODEST
RAINFALL WITH MUCH OF THE ACTIVITY...AND INVERTED-V PROFILES
SUGGEST GUSTY AND ERRATIC WINDS ARE A HIGH LIKELIHOOD AS WELL.

WINDS TONIGHT COULD REMAIN A BIT BREEZY AHEAD OF THE COLD FRONT
THAT IS STILL PROGGED TO DROP SOUTH ACROSS THE REGION STARTING
AROUND SUNRISE ON MONDAY. COOLER TEMPS ARE EXPECTED FOR MONDAY
WITH INCREASING MOISTURE AND UPSLOPE FLOW PROGGED THRU THE
AFTERNOON ACROSS THE PLAINS. A WEAK DISTURBANCE MOVING OVERHEAD IN
SOUTHWEST FLOW SHOULD SPARK OFF MORE AFTERNOON TSTMS IN THE HIGH
COUNTRY AIDED BY STRENGTHENING UPSLOPE FLOW. ADDITIONAL WEAK
VORTICITY AND MOISTURE MOVING OVERHEAD ON THE NOSE OF A JETLET
APPROACHING FROM THE SOUTHWEST ON TUESDAY WILL BRING ANOTHER
ROUND OF SHOWERS/TSTMS TO THE CWA IN THE AFTERNOON.

.LONG TERM...(WEDNESDAY THROUGH SATURDAY)
ISSUED AT 405 AM MDT SUN AUG 30 2015

WE REMAIN UNDER A BROAD SOUTHWESTERLY FLOW ALOFT WEDNESDAY THROUGH
LATE WEEK AS A AMPLIFYING UPPER TROUGH OVER THE PACIFIC NORTHWEST
STARTS TO MOVE EASTWARD. WITH FAIRLY DRY DEEP LAYERED AIRMASS WE
SHOULD SEE LITTLE IN THE WAY OF POPS EXCEPT FOR MAYBE A FEW
ISOLATED AFTERNOON/EVENING STORMS IN THE MOUNTAINS OF SE
WYOMING...MAINLY ON WEDNESDAY. BY THE WEEKEND WE WILL SEE SEVERAL
STRONGER MIDLEVEL IMPULSES MOVE THROUGH THE INCREASING
SOUTHWESTERLY FLOW ALOFT AS THE UPPER TROUGH TO THE NORTHWEST
STARTS TO EJECT OUT TO THE EAST...AND THIS IS EXPECTED TO BRING A
WEAK COLD FRONT DOWN FROM THE NORTHWEST HANGING IT UP ALONG THE
LARAMIE RANGE ON SATURDAY. THIS MAY FOCUS SOME ISOLATED TO
SCATTERED AFTERNOON/EVENING THUNDERSTORMS OVER THE EASTERN HALF OF
THE FORECAST AREA SATURDAY AFTERNOON AND EVENING.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1120 AM MDT SUN AUG 30 2015

SCATTERED THUNDERSTORMS THIS AFTERNOON...FOR RAWLINS AND LARAMIE
AS AN UPPER LEVEL DISTURBANCE MOVES ACROSS THE FORECAST AREA.
CHEYENNE COULD SEE SOME ISOLATED SHOWERS LATER INTO THE NIGHT.
BRIEF MVFR CONDITIONS CAN BE SEEN WITH A PASSING THUNDERSTORM.
OTHERWISE EXPECT VFR CONDITIONS THROUGHOUT THE DAY. WINDS ARE
EXPECTED TO PICK UP THROUGHOUT THE AFTERNOON HOURS FOR THE
NEBRASKA PANHANDLE. OVERNIGHT WINDS WILL CONTINUE TO BE GUSTY FOR
CHADRON WITH THE DEVELOPMENT OF A LLVL JET.

&&

.FIRE WEATHER...
ISSUED AT 405 AM MDT SUN AUG 30 2015

HOT AND RELATIVELY DRY CONDITIONS ARE EXPECTED TODAY OVER MUCH OF
THE DISTRICT...WITH BREEZY WINDS THIS MORNING CONTINUING THROUGH
THE AFTERNOON IN THE HIGH COUNTRY AND FOR CONVERSE/NIOBRARA
COUNTIES. WINDS LOOK TO DIMINISH ALONG AND EAST OF THE LARAMIE
RANGE AFTER NOON TODAY. THE RED FLAG WARNING REMAINS IN EFFECT
FOR FWZ 301 FOR THE COMBINATION OF DRY AND BREEZY CONDITIONS.
INCREASING MOISTURE LATER THIS MORNING AND AFTERNOON WILL GIVE
CHANCES FOR WETTING RAINS MAINLY OVER THE MOUNTAINS AND PLAINS OF
SOUTHEAST WYOMING. CHANCES FOR RAIN WILL CONTINUE OVER THE
MOUNTAINS AND SOUTHERN WYO PLAINS THRU TUESDAY.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...RED FLAG WARNING UNTIL 7 PM MDT THIS EVENING FOR WYZ301.

NE...NONE.
&&

$$

UPDATE...SML
SHORT TERM...RJM
LONG TERM...JG
AVIATION...GCC/KC
FIRE WEATHER...RJM




000
FXUS65 KCYS 301734
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
1134 AM MDT SUN AUG 30 2015

.UPDATE...
ISSUED AT 941 AM MDT SUN AUG 30 2015

MOSAIC RADAR IS SHOWING SHOWER ACTIVITY DEVELOPING ACROSS FAR
NORTHEAST UTAH AND FAR NORTHWEST COLORADO. ALSO A FEW SHOWERS NOW
SHOWING UP IN SOUTHCENTRAL WYOMING. THIS ACTIVITY WILL SPREAD EAST
ACROSS SOUTHEAST WYOMING THIS AFTERNOON ALONG WITH ISOLATED
THUNDERSTORMS. COOLING MID LEVELS OF THE ATMOSPHERE AND MID LEVEL
CONVERGENCE ASSOCIATED WITH SHORTWAVE TROUGH WILL BE A BIG FACTOR
IN SHOWERS AND THUNDERSTORMS...AS WELL AS THE RIGHT ENTRANCE
REGION OF THE UPPER LEVEL JET. THERE THREAT FOR SEVERE
THUNDERSTORMS IS LOW BUT WITH LARGE TEMPERATURE DEW POINT SPREADS
AND TYPICAL LATE AUGUST INVERTED V SOUNDING PROFILES...STRONG
WIND GUSTS WILL BE POSSIBLE WITH GUSTS TO AROUND 60 MPH NOT
COMPLETELY OUT OF THE QUESTION.

&&

.SHORT TERM...(TODAY THROUGH TUESDAY NIGHT)
ISSUED AT 405 AM MDT SUN AUG 30 2015

SOME HIGH CLOUDS ARE MOVING OVERHEAD EARLY THIS MORNING WITH SOUTH-
SOUTHWEST WINDS ON AVERAGE OF 5 TO 15 MPH OBSERVED AT MANY
LOCATIONS. THE NEAR SFC INVERSION SEEMS TO BE STRONG ENOUGH TO KEEP
THE GUSTY LLVL JET WINDS AT BAY THO SO SHOULD SEE THESE LIGHTER
WINDS PERSIST THRU THE MORNING.

THE LEESIDE PRESSURE TROUGH WILL DEEPEN THIS MORNING AS A STRONG
UPPER LEVEL SHORTWAVE MOVES ACROSS THE PAC NW AND NORTHERN
ROCKIES TODAY. WEST-SOUTHWEST SFC WINDS ARE EXPECTED TO INCREASE
AS THIS OCCURS AND AS THE INVERSION BEGINS TO LIFT AFTER SUNRISE.
FORECAST SOUNDS SHOW A DEEP MIXED LAYER UP TO ROUGHLY 550 MB BY
THIS AFTERNOON...WITH WINDS THRU THE MIXED LAYER MAXING OUT AT 20
TO 25 KTS OVER THE MOUNTAINS AND EAST CENTRAL WYOMING...AND 10 TO
15 KTS TO THE LEE OF THE LARAMIE RANGE AND POINTS EAST.
THEREFORE...EXPECT GUSTY WINDS TO PERSIST THRU THE AFTERNOON
WITHIN A CORRIDOR FROM CARBON COUNTY TO CONVERSE/NIOBRARA COUNTIES
WHILE WINDS SHOULD DIMINISH WITHIN THE DEEPENING LEESIDE TROUGH
ACROSS EXTREME SOUTHEAST WYOMING AND THE WESTERN NEBRASKA
PANHANDLE. HOT TEMPS WILL OCCUR TODAY WITH 80S AND 90S ACROSS
SOUTHEAST WYOMING AND 90S AND PERHAPS A FEW 100 DEGREE READINGS
IN THE PANHANDLE WITH THE THERMAL RIDGE OVERHEAD. A FETCH OF
SUBTROPICAL MOISTURE WILL ADVECT UP AND INTO THE CWA TODAY AS WELL
AND WILL KEEP HUMIDITIES IN THE UPPER TEENS TO LOW 20S ALONG AND
WEST OF THE LARAMIE RANGE WITH MID TO UPPER TEENS ACROSS THE
PLAINS. STILL LOOKING AT THE BEST JUXTAPOSITION OF LOW HUMIDITIES
AND GUSTY WINDS EARLY THIS AFTERNOON ACROSS FWZ 301 SO WILL KEEP
THE RED FLAG WARNING IN PLACE HERE. WINDS SHOULD BE ON THE
DOWNWARD TURN FURTHER SOUTH AND EAST WHEN HUMIDITIES WILL BE AT
THEIR LOWEST SO LOOKING AT ONLY MARGINAL FIRE WEATHER CONCERNS
HERE FOR ZONES 309 AND 310.

SHOWERS AND ISOLATED TSTMS WILL DEVELOP OVER THE MOUNTAINS THIS
AFTERNOON WITHIN THE DEEPEST MOISTURE AND AS WINDS ALOFT INCREASE
WITH THE APPROACHING SHORTWAVE. STILL THINKING SOME OF THIS
ACTIVITY WILL SHIFT TO THE PLAINS THRU THE LATE AFTERNOON AND
EVENING AS THE MOISTURE PLUME CONTINUES TO OVERSPREAD THE CWA.
GUIDANCE CONTINUES TO SHOW ENOUGH MOISTURE TO PRODUCE MODEST
RAINFALL WITH MUCH OF THE ACTIVITY...AND INVERTED-V PROFILES
SUGGEST GUSTY AND ERRATIC WINDS ARE A HIGH LIKELIHOOD AS WELL.

WINDS TONIGHT COULD REMAIN A BIT BREEZY AHEAD OF THE COLD FRONT
THAT IS STILL PROGGED TO DROP SOUTH ACROSS THE REGION STARTING
AROUND SUNRISE ON MONDAY. COOLER TEMPS ARE EXPECTED FOR MONDAY
WITH INCREASING MOISTURE AND UPSLOPE FLOW PROGGED THRU THE
AFTERNOON ACROSS THE PLAINS. A WEAK DISTURBANCE MOVING OVERHEAD IN
SOUTHWEST FLOW SHOULD SPARK OFF MORE AFTERNOON TSTMS IN THE HIGH
COUNTRY AIDED BY STRENGTHENING UPSLOPE FLOW. ADDITIONAL WEAK
VORTICITY AND MOISTURE MOVING OVERHEAD ON THE NOSE OF A JETLET
APPROACHING FROM THE SOUTHWEST ON TUESDAY WILL BRING ANOTHER
ROUND OF SHOWERS/TSTMS TO THE CWA IN THE AFTERNOON.

.LONG TERM...(WEDNESDAY THROUGH SATURDAY)
ISSUED AT 405 AM MDT SUN AUG 30 2015

WE REMAIN UNDER A BROAD SOUTHWESTERLY FLOW ALOFT WEDNESDAY THROUGH
LATE WEEK AS A AMPLIFYING UPPER TROUGH OVER THE PACIFIC NORTHWEST
STARTS TO MOVE EASTWARD. WITH FAIRLY DRY DEEP LAYERED AIRMASS WE
SHOULD SEE LITTLE IN THE WAY OF POPS EXCEPT FOR MAYBE A FEW
ISOLATED AFTERNOON/EVENING STORMS IN THE MOUNTAINS OF SE
WYOMING...MAINLY ON WEDNESDAY. BY THE WEEKEND WE WILL SEE SEVERAL
STRONGER MIDLEVEL IMPULSES MOVE THROUGH THE INCREASING
SOUTHWESTERLY FLOW ALOFT AS THE UPPER TROUGH TO THE NORTHWEST
STARTS TO EJECT OUT TO THE EAST...AND THIS IS EXPECTED TO BRING A
WEAK COLD FRONT DOWN FROM THE NORTHWEST HANGING IT UP ALONG THE
LARAMIE RANGE ON SATURDAY. THIS MAY FOCUS SOME ISOLATED TO
SCATTERED AFTERNOON/EVENING THUNDERSTORMS OVER THE EASTERN HALF OF
THE FORECAST AREA SATURDAY AFTERNOON AND EVENING.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1120 AM MDT SUN AUG 30 2015

SCATTERED THUNDERSTORMS THIS AFTERNOON...FOR RAWLINS AND LARAMIE
AS AN UPPER LEVEL DISTURBANCE MOVES ACROSS THE FORECAST AREA.
CHEYENNE COULD SEE SOME ISOLATED SHOWERS LATER INTO THE NIGHT.
BRIEF MVFR CONDITIONS CAN BE SEEN WITH A PASSING THUNDERSTORM.
OTHERWISE EXPECT VFR CONDITIONS THROUGHOUT THE DAY. WINDS ARE
EXPECTED TO PICK UP THROUGHOUT THE AFTERNOON HOURS FOR THE
NEBRASKA PANHANDLE. OVERNIGHT WINDS WILL CONTINUE TO BE GUSTY FOR
CHADRON WITH THE DEVELOPMENT OF A LLVL JET.

&&

.FIRE WEATHER...
ISSUED AT 405 AM MDT SUN AUG 30 2015

HOT AND RELATIVELY DRY CONDITIONS ARE EXPECTED TODAY OVER MUCH OF
THE DISTRICT...WITH BREEZY WINDS THIS MORNING CONTINUING THROUGH
THE AFTERNOON IN THE HIGH COUNTRY AND FOR CONVERSE/NIOBRARA
COUNTIES. WINDS LOOK TO DIMINISH ALONG AND EAST OF THE LARAMIE
RANGE AFTER NOON TODAY. THE RED FLAG WARNING REMAINS IN EFFECT
FOR FWZ 301 FOR THE COMBINATION OF DRY AND BREEZY CONDITIONS.
INCREASING MOISTURE LATER THIS MORNING AND AFTERNOON WILL GIVE
CHANCES FOR WETTING RAINS MAINLY OVER THE MOUNTAINS AND PLAINS OF
SOUTHEAST WYOMING. CHANCES FOR RAIN WILL CONTINUE OVER THE
MOUNTAINS AND SOUTHERN WYO PLAINS THRU TUESDAY.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...RED FLAG WARNING UNTIL 7 PM MDT THIS EVENING FOR WYZ301.

NE...NONE.
&&

$$

UPDATE...SML
SHORT TERM...RJM
LONG TERM...JG
AVIATION...GCC/KC
FIRE WEATHER...RJM



000
FXUS63 KUNR 301728
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
1128 AM MDT SUN AUG 30 2015

.SHORT TERM...TODAY THROUGH MONDAY NIGHT
ISSUED AT 349 AM MDT SUN AUG 30 2015

SW FLOW ALOFT WILL INCREASE TODAY AS AN UPPER TROUGH CROSSES INTO
THE PAC NW. BREEZY SWRLY LOW LEVEL FLOW ACROSS THE HIGH PLAINS WILL
KEEP WARM AND DRY AIR OVER THE AREA TODAY. SURFACE OBS ACROSS THE
NRN/NERN BLKHLS AND ADJACENT FOOTHILLS SHOWING STRONG DOWNSLOPING
KEEPING OVERNIGHT TEMPS IN THE LOW TO MID 80S ALONG THE I90
CORRIDOR. MAX TEMPS WILL REACH THE 90S TO LOWER 100S. BREEZY S/SW
WINDS OF 10 TO 20 MPH ARE EXPECTED ACROSS THE PLAINS...POSSIBLY
BREEZIER OVER SCNTRL SD. COLD FRONT WILL CROSS THE AREA LATE THIS
AFTN INTO TONIGHT...WITH THE COLDER AIR NOT REACHING THE CWA UNTIL
LATE TONIGHT. COULD SEE SOME ISOLATED STORMS DEVELOP AHEAD OF THE
FRONT...BUT DRY LOW LEVELS WILL GREATLY HINDER INSTABILITY/QPF.
MOSTLY SUNNY SKIES AND BREEZY NW WINDS EXPECTED BEHIND THE FRONTAL
BOUNDARY THROUGH MON MORNING...BUT WINDS WILL DECREASE THROUGH THE
AFTN. TEMPS MON WILL BE A GOOD 10-15 DEGREES COOLER WITH HIGHS
REACHING THE MID 70S TO MID 80S. LOW MON NIGHT WILL DROP INTO THE
MID 50S TO MID 60S.

.LONG TERM...TUESDAY THROUGH SATURDAY
ISSUED AT 349 AM MDT SUN AUG 30 2015

UPPER TROUGH OVER THE PACIFIC NORTHWEST WILL LEAD TO
RIDGING OVER CENTRAL AND EASTERN CONUS THROUGH MUCH OF NEXT WEEK.
THIS WILL CREATE WARMER THAN AVERAGE TEMPERATURES. WEAK IMPULSES IN
THE SOUTHWESTERLY UPPER FLOW COULD CREATE A FEW ISOLATED
THUNDERSTORMS ESPECIALLY WHEN COMBINED WITH POSSIBLE LOW-MID LEVEL
THETA-E ADVECTION. DUE TO THE LACK OF ANY DECENT SIGNALS AND THE
EXPECTED EXTREMELY ISOLATED NATURE OF ANY CONVECTION WILL CONTINUE
WITH THE DRY FORECAST THROUGH THURSDAY. THE UPPER TROUGH WILL SHIFT
EASTWARD TOWARD THE FORECAST AREA FROM FRIDAY THROUGH THE
WEEKEND...CREATING A BETTER CHANCE OF SHOWERS AND LEADING TO
NOTICEABLY COOLER TEMPERATURES ON SATURDAY AND SUNDAY.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY)
ISSUED AT 1126 AM MDT SUN AUG 30 2015

BREEZY SOUTHERLY WINDS WILL PREVAIL ACROSS THE AREA
TODAY. MAINLY VFR CONDITIONS ARE EXPECTED WITH ISOLD MVFR VSBYS
POSSIBLE IN SMOKE FROM WESTERN WILDFIRES. THERE IS A SLIGHT CHANCE
OF THUNDERSTORMS OVER NORTHEASTERN WYOMING AND FAR WESTERN SOUTH
DAKOTA FROM LATE THIS AFTERNOON THROUGH THIS EVENING. GUSTY WINDS
WILL BE POSSIBLE WITH ANY TS ACTIVITY. A COLD FRONT WILL PUSH
THROUGH THE AREA EARLY MONDAY MORNING...WITH A PERIOD OF GUSTY NW
WINDS EXPECTED BEHIND THE FRONT.

&&

.FIRE WEATHER...
ISSUED AT 349 AM MDT SUN AUG 30 2015

WARM AND DRY CONDITIONS WILL PERSIST ACROSS NE WY. RELATIVE
HUMIDITY ACROSS PORTIONS OF THE NORTHEAST WYOMING PLAINS WILL DROP
TO 15 PERCENT OR BELOW THIS AFTERNOON. GUSTY SOUTHWEST WINDS WILL
CONTINUE TODAY WITH SW WINDS OF 20 TO 30 MPH WITH GUSTS TO AROUND
35 MPH. A COLD FRONT WILL CROSS THE AREA LATE THIS AFTERNOON OR
TONIGHT. THERE IS A SLIGHT CHANCE FOR THUNDERSTORMS AHEAD OF THE
FRONT...WITH DRY LIGHTNING POSSIBLE.

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
WY...RED FLAG WARNING UNTIL 8 PM MDT THIS EVENING FOR WYZ259-297-298.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
WY...RED FLAG WARNING UNTIL 8 PM MDT THIS EVENING FOR WYZ259-297-298.

&&

$$

SHORT TERM...13
LONG TERM...10
AVIATION...JC
FIRE WEATHER...13



000
FXUS63 KUNR 301728
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
1128 AM MDT SUN AUG 30 2015

.SHORT TERM...TODAY THROUGH MONDAY NIGHT
ISSUED AT 349 AM MDT SUN AUG 30 2015

SW FLOW ALOFT WILL INCREASE TODAY AS AN UPPER TROUGH CROSSES INTO
THE PAC NW. BREEZY SWRLY LOW LEVEL FLOW ACROSS THE HIGH PLAINS WILL
KEEP WARM AND DRY AIR OVER THE AREA TODAY. SURFACE OBS ACROSS THE
NRN/NERN BLKHLS AND ADJACENT FOOTHILLS SHOWING STRONG DOWNSLOPING
KEEPING OVERNIGHT TEMPS IN THE LOW TO MID 80S ALONG THE I90
CORRIDOR. MAX TEMPS WILL REACH THE 90S TO LOWER 100S. BREEZY S/SW
WINDS OF 10 TO 20 MPH ARE EXPECTED ACROSS THE PLAINS...POSSIBLY
BREEZIER OVER SCNTRL SD. COLD FRONT WILL CROSS THE AREA LATE THIS
AFTN INTO TONIGHT...WITH THE COLDER AIR NOT REACHING THE CWA UNTIL
LATE TONIGHT. COULD SEE SOME ISOLATED STORMS DEVELOP AHEAD OF THE
FRONT...BUT DRY LOW LEVELS WILL GREATLY HINDER INSTABILITY/QPF.
MOSTLY SUNNY SKIES AND BREEZY NW WINDS EXPECTED BEHIND THE FRONTAL
BOUNDARY THROUGH MON MORNING...BUT WINDS WILL DECREASE THROUGH THE
AFTN. TEMPS MON WILL BE A GOOD 10-15 DEGREES COOLER WITH HIGHS
REACHING THE MID 70S TO MID 80S. LOW MON NIGHT WILL DROP INTO THE
MID 50S TO MID 60S.

.LONG TERM...TUESDAY THROUGH SATURDAY
ISSUED AT 349 AM MDT SUN AUG 30 2015

UPPER TROUGH OVER THE PACIFIC NORTHWEST WILL LEAD TO
RIDGING OVER CENTRAL AND EASTERN CONUS THROUGH MUCH OF NEXT WEEK.
THIS WILL CREATE WARMER THAN AVERAGE TEMPERATURES. WEAK IMPULSES IN
THE SOUTHWESTERLY UPPER FLOW COULD CREATE A FEW ISOLATED
THUNDERSTORMS ESPECIALLY WHEN COMBINED WITH POSSIBLE LOW-MID LEVEL
THETA-E ADVECTION. DUE TO THE LACK OF ANY DECENT SIGNALS AND THE
EXPECTED EXTREMELY ISOLATED NATURE OF ANY CONVECTION WILL CONTINUE
WITH THE DRY FORECAST THROUGH THURSDAY. THE UPPER TROUGH WILL SHIFT
EASTWARD TOWARD THE FORECAST AREA FROM FRIDAY THROUGH THE
WEEKEND...CREATING A BETTER CHANCE OF SHOWERS AND LEADING TO
NOTICEABLY COOLER TEMPERATURES ON SATURDAY AND SUNDAY.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY)
ISSUED AT 1126 AM MDT SUN AUG 30 2015

BREEZY SOUTHERLY WINDS WILL PREVAIL ACROSS THE AREA
TODAY. MAINLY VFR CONDITIONS ARE EXPECTED WITH ISOLD MVFR VSBYS
POSSIBLE IN SMOKE FROM WESTERN WILDFIRES. THERE IS A SLIGHT CHANCE
OF THUNDERSTORMS OVER NORTHEASTERN WYOMING AND FAR WESTERN SOUTH
DAKOTA FROM LATE THIS AFTERNOON THROUGH THIS EVENING. GUSTY WINDS
WILL BE POSSIBLE WITH ANY TS ACTIVITY. A COLD FRONT WILL PUSH
THROUGH THE AREA EARLY MONDAY MORNING...WITH A PERIOD OF GUSTY NW
WINDS EXPECTED BEHIND THE FRONT.

&&

.FIRE WEATHER...
ISSUED AT 349 AM MDT SUN AUG 30 2015

WARM AND DRY CONDITIONS WILL PERSIST ACROSS NE WY. RELATIVE
HUMIDITY ACROSS PORTIONS OF THE NORTHEAST WYOMING PLAINS WILL DROP
TO 15 PERCENT OR BELOW THIS AFTERNOON. GUSTY SOUTHWEST WINDS WILL
CONTINUE TODAY WITH SW WINDS OF 20 TO 30 MPH WITH GUSTS TO AROUND
35 MPH. A COLD FRONT WILL CROSS THE AREA LATE THIS AFTERNOON OR
TONIGHT. THERE IS A SLIGHT CHANCE FOR THUNDERSTORMS AHEAD OF THE
FRONT...WITH DRY LIGHTNING POSSIBLE.

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
WY...RED FLAG WARNING UNTIL 8 PM MDT THIS EVENING FOR WYZ259-297-298.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
WY...RED FLAG WARNING UNTIL 8 PM MDT THIS EVENING FOR WYZ259-297-298.

&&

$$

SHORT TERM...13
LONG TERM...10
AVIATION...JC
FIRE WEATHER...13



000
FXUS63 KUNR 301728
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
1128 AM MDT SUN AUG 30 2015

.SHORT TERM...TODAY THROUGH MONDAY NIGHT
ISSUED AT 349 AM MDT SUN AUG 30 2015

SW FLOW ALOFT WILL INCREASE TODAY AS AN UPPER TROUGH CROSSES INTO
THE PAC NW. BREEZY SWRLY LOW LEVEL FLOW ACROSS THE HIGH PLAINS WILL
KEEP WARM AND DRY AIR OVER THE AREA TODAY. SURFACE OBS ACROSS THE
NRN/NERN BLKHLS AND ADJACENT FOOTHILLS SHOWING STRONG DOWNSLOPING
KEEPING OVERNIGHT TEMPS IN THE LOW TO MID 80S ALONG THE I90
CORRIDOR. MAX TEMPS WILL REACH THE 90S TO LOWER 100S. BREEZY S/SW
WINDS OF 10 TO 20 MPH ARE EXPECTED ACROSS THE PLAINS...POSSIBLY
BREEZIER OVER SCNTRL SD. COLD FRONT WILL CROSS THE AREA LATE THIS
AFTN INTO TONIGHT...WITH THE COLDER AIR NOT REACHING THE CWA UNTIL
LATE TONIGHT. COULD SEE SOME ISOLATED STORMS DEVELOP AHEAD OF THE
FRONT...BUT DRY LOW LEVELS WILL GREATLY HINDER INSTABILITY/QPF.
MOSTLY SUNNY SKIES AND BREEZY NW WINDS EXPECTED BEHIND THE FRONTAL
BOUNDARY THROUGH MON MORNING...BUT WINDS WILL DECREASE THROUGH THE
AFTN. TEMPS MON WILL BE A GOOD 10-15 DEGREES COOLER WITH HIGHS
REACHING THE MID 70S TO MID 80S. LOW MON NIGHT WILL DROP INTO THE
MID 50S TO MID 60S.

.LONG TERM...TUESDAY THROUGH SATURDAY
ISSUED AT 349 AM MDT SUN AUG 30 2015

UPPER TROUGH OVER THE PACIFIC NORTHWEST WILL LEAD TO
RIDGING OVER CENTRAL AND EASTERN CONUS THROUGH MUCH OF NEXT WEEK.
THIS WILL CREATE WARMER THAN AVERAGE TEMPERATURES. WEAK IMPULSES IN
THE SOUTHWESTERLY UPPER FLOW COULD CREATE A FEW ISOLATED
THUNDERSTORMS ESPECIALLY WHEN COMBINED WITH POSSIBLE LOW-MID LEVEL
THETA-E ADVECTION. DUE TO THE LACK OF ANY DECENT SIGNALS AND THE
EXPECTED EXTREMELY ISOLATED NATURE OF ANY CONVECTION WILL CONTINUE
WITH THE DRY FORECAST THROUGH THURSDAY. THE UPPER TROUGH WILL SHIFT
EASTWARD TOWARD THE FORECAST AREA FROM FRIDAY THROUGH THE
WEEKEND...CREATING A BETTER CHANCE OF SHOWERS AND LEADING TO
NOTICEABLY COOLER TEMPERATURES ON SATURDAY AND SUNDAY.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY)
ISSUED AT 1126 AM MDT SUN AUG 30 2015

BREEZY SOUTHERLY WINDS WILL PREVAIL ACROSS THE AREA
TODAY. MAINLY VFR CONDITIONS ARE EXPECTED WITH ISOLD MVFR VSBYS
POSSIBLE IN SMOKE FROM WESTERN WILDFIRES. THERE IS A SLIGHT CHANCE
OF THUNDERSTORMS OVER NORTHEASTERN WYOMING AND FAR WESTERN SOUTH
DAKOTA FROM LATE THIS AFTERNOON THROUGH THIS EVENING. GUSTY WINDS
WILL BE POSSIBLE WITH ANY TS ACTIVITY. A COLD FRONT WILL PUSH
THROUGH THE AREA EARLY MONDAY MORNING...WITH A PERIOD OF GUSTY NW
WINDS EXPECTED BEHIND THE FRONT.

&&

.FIRE WEATHER...
ISSUED AT 349 AM MDT SUN AUG 30 2015

WARM AND DRY CONDITIONS WILL PERSIST ACROSS NE WY. RELATIVE
HUMIDITY ACROSS PORTIONS OF THE NORTHEAST WYOMING PLAINS WILL DROP
TO 15 PERCENT OR BELOW THIS AFTERNOON. GUSTY SOUTHWEST WINDS WILL
CONTINUE TODAY WITH SW WINDS OF 20 TO 30 MPH WITH GUSTS TO AROUND
35 MPH. A COLD FRONT WILL CROSS THE AREA LATE THIS AFTERNOON OR
TONIGHT. THERE IS A SLIGHT CHANCE FOR THUNDERSTORMS AHEAD OF THE
FRONT...WITH DRY LIGHTNING POSSIBLE.

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
WY...RED FLAG WARNING UNTIL 8 PM MDT THIS EVENING FOR WYZ259-297-298.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
WY...RED FLAG WARNING UNTIL 8 PM MDT THIS EVENING FOR WYZ259-297-298.

&&

$$

SHORT TERM...13
LONG TERM...10
AVIATION...JC
FIRE WEATHER...13



000
FXUS63 KUNR 301728
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
1128 AM MDT SUN AUG 30 2015

.SHORT TERM...TODAY THROUGH MONDAY NIGHT
ISSUED AT 349 AM MDT SUN AUG 30 2015

SW FLOW ALOFT WILL INCREASE TODAY AS AN UPPER TROUGH CROSSES INTO
THE PAC NW. BREEZY SWRLY LOW LEVEL FLOW ACROSS THE HIGH PLAINS WILL
KEEP WARM AND DRY AIR OVER THE AREA TODAY. SURFACE OBS ACROSS THE
NRN/NERN BLKHLS AND ADJACENT FOOTHILLS SHOWING STRONG DOWNSLOPING
KEEPING OVERNIGHT TEMPS IN THE LOW TO MID 80S ALONG THE I90
CORRIDOR. MAX TEMPS WILL REACH THE 90S TO LOWER 100S. BREEZY S/SW
WINDS OF 10 TO 20 MPH ARE EXPECTED ACROSS THE PLAINS...POSSIBLY
BREEZIER OVER SCNTRL SD. COLD FRONT WILL CROSS THE AREA LATE THIS
AFTN INTO TONIGHT...WITH THE COLDER AIR NOT REACHING THE CWA UNTIL
LATE TONIGHT. COULD SEE SOME ISOLATED STORMS DEVELOP AHEAD OF THE
FRONT...BUT DRY LOW LEVELS WILL GREATLY HINDER INSTABILITY/QPF.
MOSTLY SUNNY SKIES AND BREEZY NW WINDS EXPECTED BEHIND THE FRONTAL
BOUNDARY THROUGH MON MORNING...BUT WINDS WILL DECREASE THROUGH THE
AFTN. TEMPS MON WILL BE A GOOD 10-15 DEGREES COOLER WITH HIGHS
REACHING THE MID 70S TO MID 80S. LOW MON NIGHT WILL DROP INTO THE
MID 50S TO MID 60S.

.LONG TERM...TUESDAY THROUGH SATURDAY
ISSUED AT 349 AM MDT SUN AUG 30 2015

UPPER TROUGH OVER THE PACIFIC NORTHWEST WILL LEAD TO
RIDGING OVER CENTRAL AND EASTERN CONUS THROUGH MUCH OF NEXT WEEK.
THIS WILL CREATE WARMER THAN AVERAGE TEMPERATURES. WEAK IMPULSES IN
THE SOUTHWESTERLY UPPER FLOW COULD CREATE A FEW ISOLATED
THUNDERSTORMS ESPECIALLY WHEN COMBINED WITH POSSIBLE LOW-MID LEVEL
THETA-E ADVECTION. DUE TO THE LACK OF ANY DECENT SIGNALS AND THE
EXPECTED EXTREMELY ISOLATED NATURE OF ANY CONVECTION WILL CONTINUE
WITH THE DRY FORECAST THROUGH THURSDAY. THE UPPER TROUGH WILL SHIFT
EASTWARD TOWARD THE FORECAST AREA FROM FRIDAY THROUGH THE
WEEKEND...CREATING A BETTER CHANCE OF SHOWERS AND LEADING TO
NOTICEABLY COOLER TEMPERATURES ON SATURDAY AND SUNDAY.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY)
ISSUED AT 1126 AM MDT SUN AUG 30 2015

BREEZY SOUTHERLY WINDS WILL PREVAIL ACROSS THE AREA
TODAY. MAINLY VFR CONDITIONS ARE EXPECTED WITH ISOLD MVFR VSBYS
POSSIBLE IN SMOKE FROM WESTERN WILDFIRES. THERE IS A SLIGHT CHANCE
OF THUNDERSTORMS OVER NORTHEASTERN WYOMING AND FAR WESTERN SOUTH
DAKOTA FROM LATE THIS AFTERNOON THROUGH THIS EVENING. GUSTY WINDS
WILL BE POSSIBLE WITH ANY TS ACTIVITY. A COLD FRONT WILL PUSH
THROUGH THE AREA EARLY MONDAY MORNING...WITH A PERIOD OF GUSTY NW
WINDS EXPECTED BEHIND THE FRONT.

&&

.FIRE WEATHER...
ISSUED AT 349 AM MDT SUN AUG 30 2015

WARM AND DRY CONDITIONS WILL PERSIST ACROSS NE WY. RELATIVE
HUMIDITY ACROSS PORTIONS OF THE NORTHEAST WYOMING PLAINS WILL DROP
TO 15 PERCENT OR BELOW THIS AFTERNOON. GUSTY SOUTHWEST WINDS WILL
CONTINUE TODAY WITH SW WINDS OF 20 TO 30 MPH WITH GUSTS TO AROUND
35 MPH. A COLD FRONT WILL CROSS THE AREA LATE THIS AFTERNOON OR
TONIGHT. THERE IS A SLIGHT CHANCE FOR THUNDERSTORMS AHEAD OF THE
FRONT...WITH DRY LIGHTNING POSSIBLE.

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
WY...RED FLAG WARNING UNTIL 8 PM MDT THIS EVENING FOR WYZ259-297-298.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
WY...RED FLAG WARNING UNTIL 8 PM MDT THIS EVENING FOR WYZ259-297-298.

&&

$$

SHORT TERM...13
LONG TERM...10
AVIATION...JC
FIRE WEATHER...13



000
FXUS63 KUNR 301728
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
1128 AM MDT SUN AUG 30 2015

.SHORT TERM...TODAY THROUGH MONDAY NIGHT
ISSUED AT 349 AM MDT SUN AUG 30 2015

SW FLOW ALOFT WILL INCREASE TODAY AS AN UPPER TROUGH CROSSES INTO
THE PAC NW. BREEZY SWRLY LOW LEVEL FLOW ACROSS THE HIGH PLAINS WILL
KEEP WARM AND DRY AIR OVER THE AREA TODAY. SURFACE OBS ACROSS THE
NRN/NERN BLKHLS AND ADJACENT FOOTHILLS SHOWING STRONG DOWNSLOPING
KEEPING OVERNIGHT TEMPS IN THE LOW TO MID 80S ALONG THE I90
CORRIDOR. MAX TEMPS WILL REACH THE 90S TO LOWER 100S. BREEZY S/SW
WINDS OF 10 TO 20 MPH ARE EXPECTED ACROSS THE PLAINS...POSSIBLY
BREEZIER OVER SCNTRL SD. COLD FRONT WILL CROSS THE AREA LATE THIS
AFTN INTO TONIGHT...WITH THE COLDER AIR NOT REACHING THE CWA UNTIL
LATE TONIGHT. COULD SEE SOME ISOLATED STORMS DEVELOP AHEAD OF THE
FRONT...BUT DRY LOW LEVELS WILL GREATLY HINDER INSTABILITY/QPF.
MOSTLY SUNNY SKIES AND BREEZY NW WINDS EXPECTED BEHIND THE FRONTAL
BOUNDARY THROUGH MON MORNING...BUT WINDS WILL DECREASE THROUGH THE
AFTN. TEMPS MON WILL BE A GOOD 10-15 DEGREES COOLER WITH HIGHS
REACHING THE MID 70S TO MID 80S. LOW MON NIGHT WILL DROP INTO THE
MID 50S TO MID 60S.

.LONG TERM...TUESDAY THROUGH SATURDAY
ISSUED AT 349 AM MDT SUN AUG 30 2015

UPPER TROUGH OVER THE PACIFIC NORTHWEST WILL LEAD TO
RIDGING OVER CENTRAL AND EASTERN CONUS THROUGH MUCH OF NEXT WEEK.
THIS WILL CREATE WARMER THAN AVERAGE TEMPERATURES. WEAK IMPULSES IN
THE SOUTHWESTERLY UPPER FLOW COULD CREATE A FEW ISOLATED
THUNDERSTORMS ESPECIALLY WHEN COMBINED WITH POSSIBLE LOW-MID LEVEL
THETA-E ADVECTION. DUE TO THE LACK OF ANY DECENT SIGNALS AND THE
EXPECTED EXTREMELY ISOLATED NATURE OF ANY CONVECTION WILL CONTINUE
WITH THE DRY FORECAST THROUGH THURSDAY. THE UPPER TROUGH WILL SHIFT
EASTWARD TOWARD THE FORECAST AREA FROM FRIDAY THROUGH THE
WEEKEND...CREATING A BETTER CHANCE OF SHOWERS AND LEADING TO
NOTICEABLY COOLER TEMPERATURES ON SATURDAY AND SUNDAY.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY)
ISSUED AT 1126 AM MDT SUN AUG 30 2015

BREEZY SOUTHERLY WINDS WILL PREVAIL ACROSS THE AREA
TODAY. MAINLY VFR CONDITIONS ARE EXPECTED WITH ISOLD MVFR VSBYS
POSSIBLE IN SMOKE FROM WESTERN WILDFIRES. THERE IS A SLIGHT CHANCE
OF THUNDERSTORMS OVER NORTHEASTERN WYOMING AND FAR WESTERN SOUTH
DAKOTA FROM LATE THIS AFTERNOON THROUGH THIS EVENING. GUSTY WINDS
WILL BE POSSIBLE WITH ANY TS ACTIVITY. A COLD FRONT WILL PUSH
THROUGH THE AREA EARLY MONDAY MORNING...WITH A PERIOD OF GUSTY NW
WINDS EXPECTED BEHIND THE FRONT.

&&

.FIRE WEATHER...
ISSUED AT 349 AM MDT SUN AUG 30 2015

WARM AND DRY CONDITIONS WILL PERSIST ACROSS NE WY. RELATIVE
HUMIDITY ACROSS PORTIONS OF THE NORTHEAST WYOMING PLAINS WILL DROP
TO 15 PERCENT OR BELOW THIS AFTERNOON. GUSTY SOUTHWEST WINDS WILL
CONTINUE TODAY WITH SW WINDS OF 20 TO 30 MPH WITH GUSTS TO AROUND
35 MPH. A COLD FRONT WILL CROSS THE AREA LATE THIS AFTERNOON OR
TONIGHT. THERE IS A SLIGHT CHANCE FOR THUNDERSTORMS AHEAD OF THE
FRONT...WITH DRY LIGHTNING POSSIBLE.

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
WY...RED FLAG WARNING UNTIL 8 PM MDT THIS EVENING FOR WYZ259-297-298.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
WY...RED FLAG WARNING UNTIL 8 PM MDT THIS EVENING FOR WYZ259-297-298.

&&

$$

SHORT TERM...13
LONG TERM...10
AVIATION...JC
FIRE WEATHER...13




000
FXUS65 KCYS 301554
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
954 AM MDT SUN AUG 30 2015

.UPDATE...
ISSUED AT 941 AM MDT SUN AUG 30 2015

MOSAIC RADAR IS SHOWING SHOWER ACTIVITY DEVELOPING ACROSS FAR
NORTHEAST UTAH AND FAR NORTHWEST COLORADO. ALSO A FEW SHOWERS NOW
SHOWING UP IN SOUTHCENTRAL WYOMING. THIS ACTIVITY WILL SPREAD EAST
ACROSS SOUTHEAST WYOMING THIS AFTERNOON ALONG WITH ISOLATED
THUNDERSTORMS. COOLING MID LEVELS OF THE ATMOSPHERE AND MID LEVEL
CONVERGENCE ASSOCIATED WITH SHORTWAVE TROUGH WILL BE A BIG FACTOR
IN SHOWERS AND THUNDERSTORMS...AS WELL AS THE RIGHT ENTRANCE
REGION OF THE UPPER LEVEL JET. THERE THREAT FOR SEVERE
THUNDERSTORMS IS LOW BUT WITH LARGE TEMPERATURE DEW POINT SPREADS
AND TYPICAL LATE AUGUST INVERTED V SOUNDING PROFILES...STRONG
WIND GUSTS WILL BE POSSIBLE WITH GUSTS TO AROUND 60 MPH NOT
COMPLETELY OUT OF THE QUESTION.

&&

.SHORT TERM...(TODAY THROUGH TUESDAY NIGHT)
ISSUED AT 405 AM MDT SUN AUG 30 2015

SOME HIGH CLOUDS ARE MOVING OVERHEAD EARLY THIS MORNING WITH SOUTH-
SOUTHWEST WINDS ON AVERAGE OF 5 TO 15 MPH OBSERVED AT MANY
LOCATIONS. THE NEAR SFC INVERSION SEEMS TO BE STRONG ENOUGH TO KEEP
THE GUSTY LLVL JET WINDS AT BAY THO SO SHOULD SEE THESE LIGHTER
WINDS PERSIST THRU THE MORNING.

THE LEESIDE PRESSURE TROUGH WILL DEEPEN THIS MORNING AS A STRONG
UPPER LEVEL SHORTWAVE MOVES ACROSS THE PAC NW AND NORTHERN
ROCKIES TODAY. WEST-SOUTHWEST SFC WINDS ARE EXPECTED TO INCREASE
AS THIS OCCURS AND AS THE INVERSION BEGINS TO LIFT AFTER SUNRISE.
FORECAST SOUNDS SHOW A DEEP MIXED LAYER UP TO ROUGHLY 550 MB BY
THIS AFTERNOON...WITH WINDS THRU THE MIXED LAYER MAXING OUT AT 20
TO 25 KTS OVER THE MOUNTAINS AND EAST CENTRAL WYOMING...AND 10 TO
15 KTS TO THE LEE OF THE LARAMIE RANGE AND POINTS EAST.
THEREFORE...EXPECT GUSTY WINDS TO PERSIST THRU THE AFTERNOON
WITHIN A CORRIDOR FROM CARBON COUNTY TO CONVERSE/NIOBRARA COUNTIES
WHILE WINDS SHOULD DIMINISH WITHIN THE DEEPENING LEESIDE TROUGH
ACROSS EXTREME SOUTHEAST WYOMING AND THE WESTERN NEBRASKA
PANHANDLE. HOT TEMPS WILL OCCUR TODAY WITH 80S AND 90S ACROSS
SOUTHEAST WYOMING AND 90S AND PERHAPS A FEW 100 DEGREE READINGS
IN THE PANHANDLE WITH THE THERMAL RIDGE OVERHEAD. A FETCH OF
SUBTROPICAL MOISTURE WILL ADVECT UP AND INTO THE CWA TODAY AS WELL
AND WILL KEEP HUMIDITIES IN THE UPPER TEENS TO LOW 20S ALONG AND
WEST OF THE LARAMIE RANGE WITH MID TO UPPER TEENS ACROSS THE
PLAINS. STILL LOOKING AT THE BEST JUXTAPOSITION OF LOW HUMIDITIES
AND GUSTY WINDS EARLY THIS AFTERNOON ACROSS FWZ 301 SO WILL KEEP
THE RED FLAG WARNING IN PLACE HERE. WINDS SHOULD BE ON THE
DOWNWARD TURN FURTHER SOUTH AND EAST WHEN HUMIDITIES WILL BE AT
THEIR LOWEST SO LOOKING AT ONLY MARGINAL FIRE WEATHER CONCERNS
HERE FOR ZONES 309 AND 310.

SHOWERS AND ISOLATED TSTMS WILL DEVELOP OVER THE MOUNTAINS THIS
AFTERNOON WITHIN THE DEEPEST MOISTURE AND AS WINDS ALOFT INCREASE
WITH THE APPROACHING SHORTWAVE. STILL THINKING SOME OF THIS
ACTIVITY WILL SHIFT TO THE PLAINS THRU THE LATE AFTERNOON AND
EVENING AS THE MOISTURE PLUME CONTINUES TO OVERSPREAD THE CWA.
GUIDANCE CONTINUES TO SHOW ENOUGH MOISTURE TO PRODUCE MODEST
RAINFALL WITH MUCH OF THE ACTIVITY...AND INVERTED-V PROFILES
SUGGEST GUSTY AND ERRATIC WINDS ARE A HIGH LIKELIHOOD AS WELL.

WINDS TONIGHT COULD REMAIN A BIT BREEZY AHEAD OF THE COLD FRONT
THAT IS STILL PROGGED TO DROP SOUTH ACROSS THE REGION STARTING
AROUND SUNRISE ON MONDAY. COOLER TEMPS ARE EXPECTED FOR MONDAY
WITH INCREASING MOISTURE AND UPSLOPE FLOW PROGGED THRU THE
AFTERNOON ACROSS THE PLAINS. A WEAK DISTURBANCE MOVING OVERHEAD IN
SOUTHWEST FLOW SHOULD SPARK OFF MORE AFTERNOON TSTMS IN THE HIGH
COUNTRY AIDED BY STRENGTHENING UPSLOPE FLOW. ADDITIONAL WEAK
VORTICITY AND MOISTURE MOVING OVERHEAD ON THE NOSE OF A JETLET
APPROACHING FROM THE SOUTHWEST ON TUESDAY WILL BRING ANOTHER
ROUND OF SHOWERS/TSTMS TO THE CWA IN THE AFTERNOON.

.LONG TERM...(WEDNESDAY THROUGH SATURDAY)
ISSUED AT 405 AM MDT SUN AUG 30 2015

WE REMAIN UNDER A BROAD SOUTHWESTERLY FLOW ALOFT WEDNESDAY THROUGH
LATE WEEK AS A AMPLIFYING UPPER TROUGH OVER THE PACIFIC NORTHWEST
STARTS TO MOVE EASTWARD. WITH FAIRLY DRY DEEP LAYERED AIRMASS WE
SHOULD SEE LITTLE IN THE WAY OF POPS EXCEPT FOR MAYBE A FEW
ISOLATED AFTERNOON/EVENING STORMS IN THE MOUNTAINS OF SE
WYOMING...MAINLY ON WEDNESDAY. BY THE WEEKEND WE WILL SEE SEVERAL
STRONGER MIDLEVEL IMPULSES MOVE THROUGH THE INCREASING
SOUTHWESTERLY FLOW ALOFT AS THE UPPER TROUGH TO THE NORTHWEST
STARTS TO EJECT OUT TO THE EAST...AND THIS IS EXPECTED TO BRING A
WEAK COLD FRONT DOWN FROM THE NORTHWEST HANGING IT UP ALONG THE
LARAMIE RANGE ON SATURDAY. THIS MAY FOCUS SOME ISOLATED TO
SCATTERED AFTERNOON/EVENING THUNDERSTORMS OVER THE EASTERN HALF OF
THE FORECAST AREA SATURDAY AFTERNOON AND EVENING.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 537 AM MDT SUN AUG 30 2015

AXIS OF DEEPER MIDLEVEL PACIFIC MOISTURE BEING PULLED NORTHWARD
ALONG THE SOUTHERN STREAM JETSTREAK FROM SOUTHERN CALIFORNIA TO
MONTANA MOVING GRADUALLY EASTWARD INTO OUR WESTERN ZONES THIS
MORNING. THIS WILL RESULT IN THE DEVELOPMENT OF SCATTERED
THUNDERSTORMS AROUND RAWLINS AND LARAMIE THIS AFTERNOON SO HAVE
ADDED VCTS MENTION BY MID AFTERNOON FOR THOSE AIRPORTS...THEN AT
CHEYENNE BY EARLY EVENING WITH NO MENTION FARTHER EAST DUE TO THE
MORE ISOLATED COVERAGE OF STORMS AS THEY MOVE OUT ONTO THE PLAINS
BEFORE DIMINISHING. MOSTLY HIGH CIRRUS AT ALL AIRPORTS THIS
MORNING WITH SOUTHWESTERLY WINDS INCREASING BY LATE MORNING EXCEPT
MORE SOUTHERLY IN THE NEBRASKA PANHANDLE THROUGH THE AFTERNOON.


&&

.FIRE WEATHER...
ISSUED AT 405 AM MDT SUN AUG 30 2015

HOT AND RELATIVELY DRY CONDITIONS ARE EXPECTED TODAY OVER MUCH OF
THE DISTRICT...WITH BREEZY WINDS THIS MORNING CONTINUING THROUGH
THE AFTERNOON IN THE HIGH COUNTRY AND FOR CONVERSE/NIOBRARA
COUNTIES. WINDS LOOK TO DIMINISH ALONG AND EAST OF THE LARAMIE
RANGE AFTER NOON TODAY. THE RED FLAG WARNING REMAINS IN EFFECT
FOR FWZ 301 FOR THE COMBINATION OF DRY AND BREEZY CONDITIONS.
INCREASING MOISTURE LATER THIS MORNING AND AFTERNOON WILL GIVE
CHANCES FOR WETTING RAINS MAINLY OVER THE MOUNTAINS AND PLAINS OF
SOUTHEAST WYOMING. CHANCES FOR RAIN WILL CONTINUE OVER THE
MOUNTAINS AND SOUTHERN WYO PLAINS THRU TUESDAY.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...RED FLAG WARNING UNTIL 7 PM MDT THIS EVENING FOR WYZ301.

NE...NONE.
&&

$$

UPDATE...SML
SHORT TERM...RJM
LONG TERM...JG
AVIATION...JG
FIRE WEATHER...RJM



000
FXUS65 KCYS 301554
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
954 AM MDT SUN AUG 30 2015

.UPDATE...
ISSUED AT 941 AM MDT SUN AUG 30 2015

MOSAIC RADAR IS SHOWING SHOWER ACTIVITY DEVELOPING ACROSS FAR
NORTHEAST UTAH AND FAR NORTHWEST COLORADO. ALSO A FEW SHOWERS NOW
SHOWING UP IN SOUTHCENTRAL WYOMING. THIS ACTIVITY WILL SPREAD EAST
ACROSS SOUTHEAST WYOMING THIS AFTERNOON ALONG WITH ISOLATED
THUNDERSTORMS. COOLING MID LEVELS OF THE ATMOSPHERE AND MID LEVEL
CONVERGENCE ASSOCIATED WITH SHORTWAVE TROUGH WILL BE A BIG FACTOR
IN SHOWERS AND THUNDERSTORMS...AS WELL AS THE RIGHT ENTRANCE
REGION OF THE UPPER LEVEL JET. THERE THREAT FOR SEVERE
THUNDERSTORMS IS LOW BUT WITH LARGE TEMPERATURE DEW POINT SPREADS
AND TYPICAL LATE AUGUST INVERTED V SOUNDING PROFILES...STRONG
WIND GUSTS WILL BE POSSIBLE WITH GUSTS TO AROUND 60 MPH NOT
COMPLETELY OUT OF THE QUESTION.

&&

.SHORT TERM...(TODAY THROUGH TUESDAY NIGHT)
ISSUED AT 405 AM MDT SUN AUG 30 2015

SOME HIGH CLOUDS ARE MOVING OVERHEAD EARLY THIS MORNING WITH SOUTH-
SOUTHWEST WINDS ON AVERAGE OF 5 TO 15 MPH OBSERVED AT MANY
LOCATIONS. THE NEAR SFC INVERSION SEEMS TO BE STRONG ENOUGH TO KEEP
THE GUSTY LLVL JET WINDS AT BAY THO SO SHOULD SEE THESE LIGHTER
WINDS PERSIST THRU THE MORNING.

THE LEESIDE PRESSURE TROUGH WILL DEEPEN THIS MORNING AS A STRONG
UPPER LEVEL SHORTWAVE MOVES ACROSS THE PAC NW AND NORTHERN
ROCKIES TODAY. WEST-SOUTHWEST SFC WINDS ARE EXPECTED TO INCREASE
AS THIS OCCURS AND AS THE INVERSION BEGINS TO LIFT AFTER SUNRISE.
FORECAST SOUNDS SHOW A DEEP MIXED LAYER UP TO ROUGHLY 550 MB BY
THIS AFTERNOON...WITH WINDS THRU THE MIXED LAYER MAXING OUT AT 20
TO 25 KTS OVER THE MOUNTAINS AND EAST CENTRAL WYOMING...AND 10 TO
15 KTS TO THE LEE OF THE LARAMIE RANGE AND POINTS EAST.
THEREFORE...EXPECT GUSTY WINDS TO PERSIST THRU THE AFTERNOON
WITHIN A CORRIDOR FROM CARBON COUNTY TO CONVERSE/NIOBRARA COUNTIES
WHILE WINDS SHOULD DIMINISH WITHIN THE DEEPENING LEESIDE TROUGH
ACROSS EXTREME SOUTHEAST WYOMING AND THE WESTERN NEBRASKA
PANHANDLE. HOT TEMPS WILL OCCUR TODAY WITH 80S AND 90S ACROSS
SOUTHEAST WYOMING AND 90S AND PERHAPS A FEW 100 DEGREE READINGS
IN THE PANHANDLE WITH THE THERMAL RIDGE OVERHEAD. A FETCH OF
SUBTROPICAL MOISTURE WILL ADVECT UP AND INTO THE CWA TODAY AS WELL
AND WILL KEEP HUMIDITIES IN THE UPPER TEENS TO LOW 20S ALONG AND
WEST OF THE LARAMIE RANGE WITH MID TO UPPER TEENS ACROSS THE
PLAINS. STILL LOOKING AT THE BEST JUXTAPOSITION OF LOW HUMIDITIES
AND GUSTY WINDS EARLY THIS AFTERNOON ACROSS FWZ 301 SO WILL KEEP
THE RED FLAG WARNING IN PLACE HERE. WINDS SHOULD BE ON THE
DOWNWARD TURN FURTHER SOUTH AND EAST WHEN HUMIDITIES WILL BE AT
THEIR LOWEST SO LOOKING AT ONLY MARGINAL FIRE WEATHER CONCERNS
HERE FOR ZONES 309 AND 310.

SHOWERS AND ISOLATED TSTMS WILL DEVELOP OVER THE MOUNTAINS THIS
AFTERNOON WITHIN THE DEEPEST MOISTURE AND AS WINDS ALOFT INCREASE
WITH THE APPROACHING SHORTWAVE. STILL THINKING SOME OF THIS
ACTIVITY WILL SHIFT TO THE PLAINS THRU THE LATE AFTERNOON AND
EVENING AS THE MOISTURE PLUME CONTINUES TO OVERSPREAD THE CWA.
GUIDANCE CONTINUES TO SHOW ENOUGH MOISTURE TO PRODUCE MODEST
RAINFALL WITH MUCH OF THE ACTIVITY...AND INVERTED-V PROFILES
SUGGEST GUSTY AND ERRATIC WINDS ARE A HIGH LIKELIHOOD AS WELL.

WINDS TONIGHT COULD REMAIN A BIT BREEZY AHEAD OF THE COLD FRONT
THAT IS STILL PROGGED TO DROP SOUTH ACROSS THE REGION STARTING
AROUND SUNRISE ON MONDAY. COOLER TEMPS ARE EXPECTED FOR MONDAY
WITH INCREASING MOISTURE AND UPSLOPE FLOW PROGGED THRU THE
AFTERNOON ACROSS THE PLAINS. A WEAK DISTURBANCE MOVING OVERHEAD IN
SOUTHWEST FLOW SHOULD SPARK OFF MORE AFTERNOON TSTMS IN THE HIGH
COUNTRY AIDED BY STRENGTHENING UPSLOPE FLOW. ADDITIONAL WEAK
VORTICITY AND MOISTURE MOVING OVERHEAD ON THE NOSE OF A JETLET
APPROACHING FROM THE SOUTHWEST ON TUESDAY WILL BRING ANOTHER
ROUND OF SHOWERS/TSTMS TO THE CWA IN THE AFTERNOON.

.LONG TERM...(WEDNESDAY THROUGH SATURDAY)
ISSUED AT 405 AM MDT SUN AUG 30 2015

WE REMAIN UNDER A BROAD SOUTHWESTERLY FLOW ALOFT WEDNESDAY THROUGH
LATE WEEK AS A AMPLIFYING UPPER TROUGH OVER THE PACIFIC NORTHWEST
STARTS TO MOVE EASTWARD. WITH FAIRLY DRY DEEP LAYERED AIRMASS WE
SHOULD SEE LITTLE IN THE WAY OF POPS EXCEPT FOR MAYBE A FEW
ISOLATED AFTERNOON/EVENING STORMS IN THE MOUNTAINS OF SE
WYOMING...MAINLY ON WEDNESDAY. BY THE WEEKEND WE WILL SEE SEVERAL
STRONGER MIDLEVEL IMPULSES MOVE THROUGH THE INCREASING
SOUTHWESTERLY FLOW ALOFT AS THE UPPER TROUGH TO THE NORTHWEST
STARTS TO EJECT OUT TO THE EAST...AND THIS IS EXPECTED TO BRING A
WEAK COLD FRONT DOWN FROM THE NORTHWEST HANGING IT UP ALONG THE
LARAMIE RANGE ON SATURDAY. THIS MAY FOCUS SOME ISOLATED TO
SCATTERED AFTERNOON/EVENING THUNDERSTORMS OVER THE EASTERN HALF OF
THE FORECAST AREA SATURDAY AFTERNOON AND EVENING.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 537 AM MDT SUN AUG 30 2015

AXIS OF DEEPER MIDLEVEL PACIFIC MOISTURE BEING PULLED NORTHWARD
ALONG THE SOUTHERN STREAM JETSTREAK FROM SOUTHERN CALIFORNIA TO
MONTANA MOVING GRADUALLY EASTWARD INTO OUR WESTERN ZONES THIS
MORNING. THIS WILL RESULT IN THE DEVELOPMENT OF SCATTERED
THUNDERSTORMS AROUND RAWLINS AND LARAMIE THIS AFTERNOON SO HAVE
ADDED VCTS MENTION BY MID AFTERNOON FOR THOSE AIRPORTS...THEN AT
CHEYENNE BY EARLY EVENING WITH NO MENTION FARTHER EAST DUE TO THE
MORE ISOLATED COVERAGE OF STORMS AS THEY MOVE OUT ONTO THE PLAINS
BEFORE DIMINISHING. MOSTLY HIGH CIRRUS AT ALL AIRPORTS THIS
MORNING WITH SOUTHWESTERLY WINDS INCREASING BY LATE MORNING EXCEPT
MORE SOUTHERLY IN THE NEBRASKA PANHANDLE THROUGH THE AFTERNOON.


&&

.FIRE WEATHER...
ISSUED AT 405 AM MDT SUN AUG 30 2015

HOT AND RELATIVELY DRY CONDITIONS ARE EXPECTED TODAY OVER MUCH OF
THE DISTRICT...WITH BREEZY WINDS THIS MORNING CONTINUING THROUGH
THE AFTERNOON IN THE HIGH COUNTRY AND FOR CONVERSE/NIOBRARA
COUNTIES. WINDS LOOK TO DIMINISH ALONG AND EAST OF THE LARAMIE
RANGE AFTER NOON TODAY. THE RED FLAG WARNING REMAINS IN EFFECT
FOR FWZ 301 FOR THE COMBINATION OF DRY AND BREEZY CONDITIONS.
INCREASING MOISTURE LATER THIS MORNING AND AFTERNOON WILL GIVE
CHANCES FOR WETTING RAINS MAINLY OVER THE MOUNTAINS AND PLAINS OF
SOUTHEAST WYOMING. CHANCES FOR RAIN WILL CONTINUE OVER THE
MOUNTAINS AND SOUTHERN WYO PLAINS THRU TUESDAY.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...RED FLAG WARNING UNTIL 7 PM MDT THIS EVENING FOR WYZ301.

NE...NONE.
&&

$$

UPDATE...SML
SHORT TERM...RJM
LONG TERM...JG
AVIATION...JG
FIRE WEATHER...RJM




000
FXUS65 KCYS 301554
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
954 AM MDT SUN AUG 30 2015

.UPDATE...
ISSUED AT 941 AM MDT SUN AUG 30 2015

MOSAIC RADAR IS SHOWING SHOWER ACTIVITY DEVELOPING ACROSS FAR
NORTHEAST UTAH AND FAR NORTHWEST COLORADO. ALSO A FEW SHOWERS NOW
SHOWING UP IN SOUTHCENTRAL WYOMING. THIS ACTIVITY WILL SPREAD EAST
ACROSS SOUTHEAST WYOMING THIS AFTERNOON ALONG WITH ISOLATED
THUNDERSTORMS. COOLING MID LEVELS OF THE ATMOSPHERE AND MID LEVEL
CONVERGENCE ASSOCIATED WITH SHORTWAVE TROUGH WILL BE A BIG FACTOR
IN SHOWERS AND THUNDERSTORMS...AS WELL AS THE RIGHT ENTRANCE
REGION OF THE UPPER LEVEL JET. THERE THREAT FOR SEVERE
THUNDERSTORMS IS LOW BUT WITH LARGE TEMPERATURE DEW POINT SPREADS
AND TYPICAL LATE AUGUST INVERTED V SOUNDING PROFILES...STRONG
WIND GUSTS WILL BE POSSIBLE WITH GUSTS TO AROUND 60 MPH NOT
COMPLETELY OUT OF THE QUESTION.

&&

.SHORT TERM...(TODAY THROUGH TUESDAY NIGHT)
ISSUED AT 405 AM MDT SUN AUG 30 2015

SOME HIGH CLOUDS ARE MOVING OVERHEAD EARLY THIS MORNING WITH SOUTH-
SOUTHWEST WINDS ON AVERAGE OF 5 TO 15 MPH OBSERVED AT MANY
LOCATIONS. THE NEAR SFC INVERSION SEEMS TO BE STRONG ENOUGH TO KEEP
THE GUSTY LLVL JET WINDS AT BAY THO SO SHOULD SEE THESE LIGHTER
WINDS PERSIST THRU THE MORNING.

THE LEESIDE PRESSURE TROUGH WILL DEEPEN THIS MORNING AS A STRONG
UPPER LEVEL SHORTWAVE MOVES ACROSS THE PAC NW AND NORTHERN
ROCKIES TODAY. WEST-SOUTHWEST SFC WINDS ARE EXPECTED TO INCREASE
AS THIS OCCURS AND AS THE INVERSION BEGINS TO LIFT AFTER SUNRISE.
FORECAST SOUNDS SHOW A DEEP MIXED LAYER UP TO ROUGHLY 550 MB BY
THIS AFTERNOON...WITH WINDS THRU THE MIXED LAYER MAXING OUT AT 20
TO 25 KTS OVER THE MOUNTAINS AND EAST CENTRAL WYOMING...AND 10 TO
15 KTS TO THE LEE OF THE LARAMIE RANGE AND POINTS EAST.
THEREFORE...EXPECT GUSTY WINDS TO PERSIST THRU THE AFTERNOON
WITHIN A CORRIDOR FROM CARBON COUNTY TO CONVERSE/NIOBRARA COUNTIES
WHILE WINDS SHOULD DIMINISH WITHIN THE DEEPENING LEESIDE TROUGH
ACROSS EXTREME SOUTHEAST WYOMING AND THE WESTERN NEBRASKA
PANHANDLE. HOT TEMPS WILL OCCUR TODAY WITH 80S AND 90S ACROSS
SOUTHEAST WYOMING AND 90S AND PERHAPS A FEW 100 DEGREE READINGS
IN THE PANHANDLE WITH THE THERMAL RIDGE OVERHEAD. A FETCH OF
SUBTROPICAL MOISTURE WILL ADVECT UP AND INTO THE CWA TODAY AS WELL
AND WILL KEEP HUMIDITIES IN THE UPPER TEENS TO LOW 20S ALONG AND
WEST OF THE LARAMIE RANGE WITH MID TO UPPER TEENS ACROSS THE
PLAINS. STILL LOOKING AT THE BEST JUXTAPOSITION OF LOW HUMIDITIES
AND GUSTY WINDS EARLY THIS AFTERNOON ACROSS FWZ 301 SO WILL KEEP
THE RED FLAG WARNING IN PLACE HERE. WINDS SHOULD BE ON THE
DOWNWARD TURN FURTHER SOUTH AND EAST WHEN HUMIDITIES WILL BE AT
THEIR LOWEST SO LOOKING AT ONLY MARGINAL FIRE WEATHER CONCERNS
HERE FOR ZONES 309 AND 310.

SHOWERS AND ISOLATED TSTMS WILL DEVELOP OVER THE MOUNTAINS THIS
AFTERNOON WITHIN THE DEEPEST MOISTURE AND AS WINDS ALOFT INCREASE
WITH THE APPROACHING SHORTWAVE. STILL THINKING SOME OF THIS
ACTIVITY WILL SHIFT TO THE PLAINS THRU THE LATE AFTERNOON AND
EVENING AS THE MOISTURE PLUME CONTINUES TO OVERSPREAD THE CWA.
GUIDANCE CONTINUES TO SHOW ENOUGH MOISTURE TO PRODUCE MODEST
RAINFALL WITH MUCH OF THE ACTIVITY...AND INVERTED-V PROFILES
SUGGEST GUSTY AND ERRATIC WINDS ARE A HIGH LIKELIHOOD AS WELL.

WINDS TONIGHT COULD REMAIN A BIT BREEZY AHEAD OF THE COLD FRONT
THAT IS STILL PROGGED TO DROP SOUTH ACROSS THE REGION STARTING
AROUND SUNRISE ON MONDAY. COOLER TEMPS ARE EXPECTED FOR MONDAY
WITH INCREASING MOISTURE AND UPSLOPE FLOW PROGGED THRU THE
AFTERNOON ACROSS THE PLAINS. A WEAK DISTURBANCE MOVING OVERHEAD IN
SOUTHWEST FLOW SHOULD SPARK OFF MORE AFTERNOON TSTMS IN THE HIGH
COUNTRY AIDED BY STRENGTHENING UPSLOPE FLOW. ADDITIONAL WEAK
VORTICITY AND MOISTURE MOVING OVERHEAD ON THE NOSE OF A JETLET
APPROACHING FROM THE SOUTHWEST ON TUESDAY WILL BRING ANOTHER
ROUND OF SHOWERS/TSTMS TO THE CWA IN THE AFTERNOON.

.LONG TERM...(WEDNESDAY THROUGH SATURDAY)
ISSUED AT 405 AM MDT SUN AUG 30 2015

WE REMAIN UNDER A BROAD SOUTHWESTERLY FLOW ALOFT WEDNESDAY THROUGH
LATE WEEK AS A AMPLIFYING UPPER TROUGH OVER THE PACIFIC NORTHWEST
STARTS TO MOVE EASTWARD. WITH FAIRLY DRY DEEP LAYERED AIRMASS WE
SHOULD SEE LITTLE IN THE WAY OF POPS EXCEPT FOR MAYBE A FEW
ISOLATED AFTERNOON/EVENING STORMS IN THE MOUNTAINS OF SE
WYOMING...MAINLY ON WEDNESDAY. BY THE WEEKEND WE WILL SEE SEVERAL
STRONGER MIDLEVEL IMPULSES MOVE THROUGH THE INCREASING
SOUTHWESTERLY FLOW ALOFT AS THE UPPER TROUGH TO THE NORTHWEST
STARTS TO EJECT OUT TO THE EAST...AND THIS IS EXPECTED TO BRING A
WEAK COLD FRONT DOWN FROM THE NORTHWEST HANGING IT UP ALONG THE
LARAMIE RANGE ON SATURDAY. THIS MAY FOCUS SOME ISOLATED TO
SCATTERED AFTERNOON/EVENING THUNDERSTORMS OVER THE EASTERN HALF OF
THE FORECAST AREA SATURDAY AFTERNOON AND EVENING.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 537 AM MDT SUN AUG 30 2015

AXIS OF DEEPER MIDLEVEL PACIFIC MOISTURE BEING PULLED NORTHWARD
ALONG THE SOUTHERN STREAM JETSTREAK FROM SOUTHERN CALIFORNIA TO
MONTANA MOVING GRADUALLY EASTWARD INTO OUR WESTERN ZONES THIS
MORNING. THIS WILL RESULT IN THE DEVELOPMENT OF SCATTERED
THUNDERSTORMS AROUND RAWLINS AND LARAMIE THIS AFTERNOON SO HAVE
ADDED VCTS MENTION BY MID AFTERNOON FOR THOSE AIRPORTS...THEN AT
CHEYENNE BY EARLY EVENING WITH NO MENTION FARTHER EAST DUE TO THE
MORE ISOLATED COVERAGE OF STORMS AS THEY MOVE OUT ONTO THE PLAINS
BEFORE DIMINISHING. MOSTLY HIGH CIRRUS AT ALL AIRPORTS THIS
MORNING WITH SOUTHWESTERLY WINDS INCREASING BY LATE MORNING EXCEPT
MORE SOUTHERLY IN THE NEBRASKA PANHANDLE THROUGH THE AFTERNOON.


&&

.FIRE WEATHER...
ISSUED AT 405 AM MDT SUN AUG 30 2015

HOT AND RELATIVELY DRY CONDITIONS ARE EXPECTED TODAY OVER MUCH OF
THE DISTRICT...WITH BREEZY WINDS THIS MORNING CONTINUING THROUGH
THE AFTERNOON IN THE HIGH COUNTRY AND FOR CONVERSE/NIOBRARA
COUNTIES. WINDS LOOK TO DIMINISH ALONG AND EAST OF THE LARAMIE
RANGE AFTER NOON TODAY. THE RED FLAG WARNING REMAINS IN EFFECT
FOR FWZ 301 FOR THE COMBINATION OF DRY AND BREEZY CONDITIONS.
INCREASING MOISTURE LATER THIS MORNING AND AFTERNOON WILL GIVE
CHANCES FOR WETTING RAINS MAINLY OVER THE MOUNTAINS AND PLAINS OF
SOUTHEAST WYOMING. CHANCES FOR RAIN WILL CONTINUE OVER THE
MOUNTAINS AND SOUTHERN WYO PLAINS THRU TUESDAY.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...RED FLAG WARNING UNTIL 7 PM MDT THIS EVENING FOR WYZ301.

NE...NONE.
&&

$$

UPDATE...SML
SHORT TERM...RJM
LONG TERM...JG
AVIATION...JG
FIRE WEATHER...RJM




000
FXUS65 KCYS 301554
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
954 AM MDT SUN AUG 30 2015

.UPDATE...
ISSUED AT 941 AM MDT SUN AUG 30 2015

MOSAIC RADAR IS SHOWING SHOWER ACTIVITY DEVELOPING ACROSS FAR
NORTHEAST UTAH AND FAR NORTHWEST COLORADO. ALSO A FEW SHOWERS NOW
SHOWING UP IN SOUTHCENTRAL WYOMING. THIS ACTIVITY WILL SPREAD EAST
ACROSS SOUTHEAST WYOMING THIS AFTERNOON ALONG WITH ISOLATED
THUNDERSTORMS. COOLING MID LEVELS OF THE ATMOSPHERE AND MID LEVEL
CONVERGENCE ASSOCIATED WITH SHORTWAVE TROUGH WILL BE A BIG FACTOR
IN SHOWERS AND THUNDERSTORMS...AS WELL AS THE RIGHT ENTRANCE
REGION OF THE UPPER LEVEL JET. THERE THREAT FOR SEVERE
THUNDERSTORMS IS LOW BUT WITH LARGE TEMPERATURE DEW POINT SPREADS
AND TYPICAL LATE AUGUST INVERTED V SOUNDING PROFILES...STRONG
WIND GUSTS WILL BE POSSIBLE WITH GUSTS TO AROUND 60 MPH NOT
COMPLETELY OUT OF THE QUESTION.

&&

.SHORT TERM...(TODAY THROUGH TUESDAY NIGHT)
ISSUED AT 405 AM MDT SUN AUG 30 2015

SOME HIGH CLOUDS ARE MOVING OVERHEAD EARLY THIS MORNING WITH SOUTH-
SOUTHWEST WINDS ON AVERAGE OF 5 TO 15 MPH OBSERVED AT MANY
LOCATIONS. THE NEAR SFC INVERSION SEEMS TO BE STRONG ENOUGH TO KEEP
THE GUSTY LLVL JET WINDS AT BAY THO SO SHOULD SEE THESE LIGHTER
WINDS PERSIST THRU THE MORNING.

THE LEESIDE PRESSURE TROUGH WILL DEEPEN THIS MORNING AS A STRONG
UPPER LEVEL SHORTWAVE MOVES ACROSS THE PAC NW AND NORTHERN
ROCKIES TODAY. WEST-SOUTHWEST SFC WINDS ARE EXPECTED TO INCREASE
AS THIS OCCURS AND AS THE INVERSION BEGINS TO LIFT AFTER SUNRISE.
FORECAST SOUNDS SHOW A DEEP MIXED LAYER UP TO ROUGHLY 550 MB BY
THIS AFTERNOON...WITH WINDS THRU THE MIXED LAYER MAXING OUT AT 20
TO 25 KTS OVER THE MOUNTAINS AND EAST CENTRAL WYOMING...AND 10 TO
15 KTS TO THE LEE OF THE LARAMIE RANGE AND POINTS EAST.
THEREFORE...EXPECT GUSTY WINDS TO PERSIST THRU THE AFTERNOON
WITHIN A CORRIDOR FROM CARBON COUNTY TO CONVERSE/NIOBRARA COUNTIES
WHILE WINDS SHOULD DIMINISH WITHIN THE DEEPENING LEESIDE TROUGH
ACROSS EXTREME SOUTHEAST WYOMING AND THE WESTERN NEBRASKA
PANHANDLE. HOT TEMPS WILL OCCUR TODAY WITH 80S AND 90S ACROSS
SOUTHEAST WYOMING AND 90S AND PERHAPS A FEW 100 DEGREE READINGS
IN THE PANHANDLE WITH THE THERMAL RIDGE OVERHEAD. A FETCH OF
SUBTROPICAL MOISTURE WILL ADVECT UP AND INTO THE CWA TODAY AS WELL
AND WILL KEEP HUMIDITIES IN THE UPPER TEENS TO LOW 20S ALONG AND
WEST OF THE LARAMIE RANGE WITH MID TO UPPER TEENS ACROSS THE
PLAINS. STILL LOOKING AT THE BEST JUXTAPOSITION OF LOW HUMIDITIES
AND GUSTY WINDS EARLY THIS AFTERNOON ACROSS FWZ 301 SO WILL KEEP
THE RED FLAG WARNING IN PLACE HERE. WINDS SHOULD BE ON THE
DOWNWARD TURN FURTHER SOUTH AND EAST WHEN HUMIDITIES WILL BE AT
THEIR LOWEST SO LOOKING AT ONLY MARGINAL FIRE WEATHER CONCERNS
HERE FOR ZONES 309 AND 310.

SHOWERS AND ISOLATED TSTMS WILL DEVELOP OVER THE MOUNTAINS THIS
AFTERNOON WITHIN THE DEEPEST MOISTURE AND AS WINDS ALOFT INCREASE
WITH THE APPROACHING SHORTWAVE. STILL THINKING SOME OF THIS
ACTIVITY WILL SHIFT TO THE PLAINS THRU THE LATE AFTERNOON AND
EVENING AS THE MOISTURE PLUME CONTINUES TO OVERSPREAD THE CWA.
GUIDANCE CONTINUES TO SHOW ENOUGH MOISTURE TO PRODUCE MODEST
RAINFALL WITH MUCH OF THE ACTIVITY...AND INVERTED-V PROFILES
SUGGEST GUSTY AND ERRATIC WINDS ARE A HIGH LIKELIHOOD AS WELL.

WINDS TONIGHT COULD REMAIN A BIT BREEZY AHEAD OF THE COLD FRONT
THAT IS STILL PROGGED TO DROP SOUTH ACROSS THE REGION STARTING
AROUND SUNRISE ON MONDAY. COOLER TEMPS ARE EXPECTED FOR MONDAY
WITH INCREASING MOISTURE AND UPSLOPE FLOW PROGGED THRU THE
AFTERNOON ACROSS THE PLAINS. A WEAK DISTURBANCE MOVING OVERHEAD IN
SOUTHWEST FLOW SHOULD SPARK OFF MORE AFTERNOON TSTMS IN THE HIGH
COUNTRY AIDED BY STRENGTHENING UPSLOPE FLOW. ADDITIONAL WEAK
VORTICITY AND MOISTURE MOVING OVERHEAD ON THE NOSE OF A JETLET
APPROACHING FROM THE SOUTHWEST ON TUESDAY WILL BRING ANOTHER
ROUND OF SHOWERS/TSTMS TO THE CWA IN THE AFTERNOON.

.LONG TERM...(WEDNESDAY THROUGH SATURDAY)
ISSUED AT 405 AM MDT SUN AUG 30 2015

WE REMAIN UNDER A BROAD SOUTHWESTERLY FLOW ALOFT WEDNESDAY THROUGH
LATE WEEK AS A AMPLIFYING UPPER TROUGH OVER THE PACIFIC NORTHWEST
STARTS TO MOVE EASTWARD. WITH FAIRLY DRY DEEP LAYERED AIRMASS WE
SHOULD SEE LITTLE IN THE WAY OF POPS EXCEPT FOR MAYBE A FEW
ISOLATED AFTERNOON/EVENING STORMS IN THE MOUNTAINS OF SE
WYOMING...MAINLY ON WEDNESDAY. BY THE WEEKEND WE WILL SEE SEVERAL
STRONGER MIDLEVEL IMPULSES MOVE THROUGH THE INCREASING
SOUTHWESTERLY FLOW ALOFT AS THE UPPER TROUGH TO THE NORTHWEST
STARTS TO EJECT OUT TO THE EAST...AND THIS IS EXPECTED TO BRING A
WEAK COLD FRONT DOWN FROM THE NORTHWEST HANGING IT UP ALONG THE
LARAMIE RANGE ON SATURDAY. THIS MAY FOCUS SOME ISOLATED TO
SCATTERED AFTERNOON/EVENING THUNDERSTORMS OVER THE EASTERN HALF OF
THE FORECAST AREA SATURDAY AFTERNOON AND EVENING.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 537 AM MDT SUN AUG 30 2015

AXIS OF DEEPER MIDLEVEL PACIFIC MOISTURE BEING PULLED NORTHWARD
ALONG THE SOUTHERN STREAM JETSTREAK FROM SOUTHERN CALIFORNIA TO
MONTANA MOVING GRADUALLY EASTWARD INTO OUR WESTERN ZONES THIS
MORNING. THIS WILL RESULT IN THE DEVELOPMENT OF SCATTERED
THUNDERSTORMS AROUND RAWLINS AND LARAMIE THIS AFTERNOON SO HAVE
ADDED VCTS MENTION BY MID AFTERNOON FOR THOSE AIRPORTS...THEN AT
CHEYENNE BY EARLY EVENING WITH NO MENTION FARTHER EAST DUE TO THE
MORE ISOLATED COVERAGE OF STORMS AS THEY MOVE OUT ONTO THE PLAINS
BEFORE DIMINISHING. MOSTLY HIGH CIRRUS AT ALL AIRPORTS THIS
MORNING WITH SOUTHWESTERLY WINDS INCREASING BY LATE MORNING EXCEPT
MORE SOUTHERLY IN THE NEBRASKA PANHANDLE THROUGH THE AFTERNOON.


&&

.FIRE WEATHER...
ISSUED AT 405 AM MDT SUN AUG 30 2015

HOT AND RELATIVELY DRY CONDITIONS ARE EXPECTED TODAY OVER MUCH OF
THE DISTRICT...WITH BREEZY WINDS THIS MORNING CONTINUING THROUGH
THE AFTERNOON IN THE HIGH COUNTRY AND FOR CONVERSE/NIOBRARA
COUNTIES. WINDS LOOK TO DIMINISH ALONG AND EAST OF THE LARAMIE
RANGE AFTER NOON TODAY. THE RED FLAG WARNING REMAINS IN EFFECT
FOR FWZ 301 FOR THE COMBINATION OF DRY AND BREEZY CONDITIONS.
INCREASING MOISTURE LATER THIS MORNING AND AFTERNOON WILL GIVE
CHANCES FOR WETTING RAINS MAINLY OVER THE MOUNTAINS AND PLAINS OF
SOUTHEAST WYOMING. CHANCES FOR RAIN WILL CONTINUE OVER THE
MOUNTAINS AND SOUTHERN WYO PLAINS THRU TUESDAY.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...RED FLAG WARNING UNTIL 7 PM MDT THIS EVENING FOR WYZ301.

NE...NONE.
&&

$$

UPDATE...SML
SHORT TERM...RJM
LONG TERM...JG
AVIATION...JG
FIRE WEATHER...RJM



000
FXUS65 KCYS 301137 AAA
AFDCYS

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE CHEYENNE WY
537 AM MDT SUN AUG 30 2015

.UPDATE...FOR THE 6 AM AVIATION FORECAST PACKAGE UPDATE.

&&

.SHORT TERM...(TODAY THROUGH TUESDAY NIGHT)
ISSUED AT 405 AM MDT SUN AUG 30 2015

SOME HIGH CLOUDS ARE MOVING OVERHEAD EARLY THIS MORNING WITH SOUTH-
SOUTHWEST WINDS ON AVERAGE OF 5 TO 15 MPH OBSERVED AT MANY
LOCATIONS. THE NEAR SFC INVERSION SEEMS TO BE STRONG ENOUGH TO KEEP
THE GUSTY LLVL JET WINDS AT BAY THO SO SHOULD SEE THESE LIGHTER
WINDS PERSIST THRU THE MORNING.

THE LEESIDE PRESSURE TROUGH WILL DEEPEN THIS MORNING AS A STRONG
UPPER LEVEL SHORTWAVE MOVES ACROSS THE PAC NW AND NORTHERN
ROCKIES TODAY. WEST-SOUTHWEST SFC WINDS ARE EXPECTED TO INCREASE
AS THIS OCCURS AND AS THE INVERSION BEGINS TO LIFT AFTER SUNRISE.
FORECAST SOUNDS SHOW A DEEP MIXED LAYER UP TO ROUGHLY 550 MB BY
THIS AFTERNOON...WITH WINDS THRU THE MIXED LAYER MAXING OUT AT 20
TO 25 KTS OVER THE MOUNTAINS AND EAST CENTRAL WYOMING...AND 10 TO
15 KTS TO THE LEE OF THE LARAMIE RANGE AND POINTS EAST.
THEREFORE...EXPECT GUSTY WINDS TO PERSIST THRU THE AFTERNOON
WITHIN A CORRIDOR FROM CARBON COUNTY TO CONVERSE/NIOBRARA COUNTIES
WHILE WINDS SHOULD DIMINISH WITHIN THE DEEPENING LEESIDE TROUGH
ACROSS EXTREME SOUTHEAST WYOMING AND THE WESTERN NEBRASKA
PANHANDLE. HOT TEMPS WILL OCCUR TODAY WITH 80S AND 90S ACROSS
SOUTHEAST WYOMING AND 90S AND PERHAPS A FEW 100 DEGREE READINGS
IN THE PANHANDLE WITH THE THERMAL RIDGE OVERHEAD. A FETCH OF
SUBTROPICAL MOISTURE WILL ADVECT UP AND INTO THE CWA TODAY AS WELL
AND WILL KEEP HUMIDITIES IN THE UPPER TEENS TO LOW 20S ALONG AND
WEST OF THE LARAMIE RANGE WITH MID TO UPPER TEENS ACROSS THE
PLAINS. STILL LOOKING AT THE BEST JUXTAPOSITION OF LOW HUMIDITIES
AND GUSTY WINDS EARLY THIS AFTERNOON ACROSS FWZ 301 SO WILL KEEP
THE RED FLAG WARNING IN PLACE HERE. WINDS SHOULD BE ON THE
DOWNWARD TURN FURTHER SOUTH AND EAST WHEN HUMIDITIES WILL BE AT
THEIR LOWEST SO LOOKING AT ONLY MARGINAL FIRE WEATHER CONCERNS
HERE FOR ZONES 309 AND 310.

SHOWERS AND ISOLATED TSTMS WILL DEVELOP OVER THE MOUNTAINS THIS
AFTERNOON WITHIN THE DEEPEST MOISTURE AND AS WINDS ALOFT INCREASE
WITH THE APPROACHING SHORTWAVE. STILL THINKING SOME OF THIS
ACTIVITY WILL SHIFT TO THE PLAINS THRU THE LATE AFTERNOON AND
EVENING AS THE MOISTURE PLUME CONTINUES TO OVERSPREAD THE CWA.
GUIDANCE CONTINUES TO SHOW ENOUGH MOISTURE TO PRODUCE MODEST
RAINFALL WITH MUCH OF THE ACTIVITY...AND INVERTED-V PROFILES
SUGGEST GUSTY AND ERRATIC WINDS ARE A HIGH LIKELIHOOD AS WELL.

WINDS TONIGHT COULD REMAIN A BIT BREEZY AHEAD OF THE COLD FRONT
THAT IS STILL PROGGED TO DROP SOUTH ACROSS THE REGION STARTING
AROUND SUNRISE ON MONDAY. COOLER TEMPS ARE EXPECTED FOR MONDAY
WITH INCREASING MOISTURE AND UPSLOPE FLOW PROGGED THRU THE
AFTERNOON ACROSS THE PLAINS. A WEAK DISTURBANCE MOVING OVERHEAD IN
SOUTHWEST FLOW SHOULD SPARK OFF MORE AFTERNOON TSTMS IN THE HIGH
COUNTRY AIDED BY STRENGTHENING UPSLOPE FLOW. ADDITIONAL WEAK
VORTICITY AND MOISTURE MOVING OVERHEAD ON THE NOSE OF A JETLET
APPROACHING FROM THE SOUTHWEST ON TUESDAY WILL BRING ANOTHER
ROUND OF SHOWERS/TSTMS TO THE CWA IN THE AFTERNOON.

.LONG TERM...(WEDNESDAY THROUGH SATURDAY)
ISSUED AT 405 AM MDT SUN AUG 30 2015

WE REMAIN UNDER A BROAD SOUTHWESTERLY FLOW ALOFT WEDNESDAY THROUGH
LATE WEEK AS A AMPLIFYING UPPER TROUGH OVER THE PACIFIC NORTHWEST
STARTS TO MOVE EASTWARD. WITH FAIRLY DRY DEEP LAYERED AIRMASS WE
SHOULD SEE LITTLE IN THE WAY OF POPS EXCEPT FOR MAYBE A FEW
ISOLATED AFTERNOON/EVENING STORMS IN THE MOUNTAINS OF SE
WYOMING...MAINLY ON WEDNESDAY. BY THE WEEKEND WE WILL SEE SEVERAL
STRONGER MIDLEVEL IMPULSES MOVE THROUGH THE INCREASING
SOUTHWESTERLY FLOW ALOFT AS THE UPPER TROUGH TO THE NORTHWEST
STARTS TO EJECT OUT TO THE EAST...AND THIS IS EXPECTED TO BRING A
WEAK COLD FRONT DOWN FROM THE NORTHWEST HANGING IT UP ALONG THE
LARAMIE RANGE ON SATURDAY. THIS MAY FOCUS SOME ISOLATED TO
SCATTERED AFTERNOON/EVENING THUNDERSTORMS OVER THE EASTERN HALF OF
THE FORECAST AREA SATURDAY AFTERNOON AND EVENING.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 537 AM MDT SUN AUG 30 2015

AXIS OF DEEPER MIDLEVEL PACIFIC MOISTURE BEING PULLED NORTHWARD
ALONG THE SOUTHERN STREAM JETSTREAK FROM SOUTHERN CALIFORNIA TO
MONTANA MOVING GRADUALLY EASTWARD INTO OUR WESTERN ZONES THIS
MORNING. THIS WILL RESULT IN THE DEVELOPMENT OF SCATTERED
THUNDERSTORMS AROUND RAWLINS AND LARAMIE THIS AFTERNOON SO HAVE
ADDED VCTS MENTION BY MID AFTERNOON FOR THOSE AIRPORTS...THEN AT
CHEYENNE BY EARLY EVENING WITH NO MENTION FARTHER EAST DUE TO THE
MORE ISOLATED COVERAGE OF STORMS AS THEY MOVE OUT ONTO THE PLAINS
BEFORE DIMINISHING. MOSTLY HIGH CIRRUS AT ALL AIRPORTS THIS
MORNING WITH SOUTHWESTERLY WINDS INCREASING BY LATE MORNING EXCEPT
MORE SOUTHERLY IN THE NEBRASKA PANHANDLE THROUGH THE AFTERNOON.

&&

.FIRE WEATHER...
ISSUED AT 405 AM MDT SUN AUG 30 2015

HOT AND RELATIVELY DRY CONDITIONS ARE EXPECTED TODAY OVER MUCH OF
THE DISTRICT...WITH BREEZY WINDS THIS MORNING CONTINUING THROUGH
THE AFTERNOON IN THE HIGH COUNTRY AND FOR CONVERSE/NIOBRARA
COUNTIES. WINDS LOOK TO DIMINISH ALONG AND EAST OF THE LARAMIE
RANGE AFTER NOON TODAY. THE RED FLAG WARNING REMAINS IN EFFECT
FOR FWZ 301 FOR THE COMBINATION OF DRY AND BREEZY CONDITIONS.
INCREASING MOISTURE LATER THIS MORNING AND AFTERNOON WILL GIVE
CHANCES FOR WETTING RAINS MAINLY OVER THE MOUNTAINS AND PLAINS OF
SOUTHEAST WYOMING. CHANCES FOR RAIN WILL CONTINUE OVER THE
MOUNTAINS AND SOUTHERN WYO PLAINS THRU TUESDAY.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...RED FLAG WARNING FROM 11 AM THIS MORNING TO 7 PM MDT THIS
     EVENING FOR WYZ301.

NE...NONE.
&&

$$

SHORT TERM...RJM
LONG TERM...JG
AVIATION...JG
FIRE WEATHER...RJM



000
FXUS65 KCYS 301137 AAA
AFDCYS

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE CHEYENNE WY
537 AM MDT SUN AUG 30 2015

.UPDATE...FOR THE 6 AM AVIATION FORECAST PACKAGE UPDATE.

&&

.SHORT TERM...(TODAY THROUGH TUESDAY NIGHT)
ISSUED AT 405 AM MDT SUN AUG 30 2015

SOME HIGH CLOUDS ARE MOVING OVERHEAD EARLY THIS MORNING WITH SOUTH-
SOUTHWEST WINDS ON AVERAGE OF 5 TO 15 MPH OBSERVED AT MANY
LOCATIONS. THE NEAR SFC INVERSION SEEMS TO BE STRONG ENOUGH TO KEEP
THE GUSTY LLVL JET WINDS AT BAY THO SO SHOULD SEE THESE LIGHTER
WINDS PERSIST THRU THE MORNING.

THE LEESIDE PRESSURE TROUGH WILL DEEPEN THIS MORNING AS A STRONG
UPPER LEVEL SHORTWAVE MOVES ACROSS THE PAC NW AND NORTHERN
ROCKIES TODAY. WEST-SOUTHWEST SFC WINDS ARE EXPECTED TO INCREASE
AS THIS OCCURS AND AS THE INVERSION BEGINS TO LIFT AFTER SUNRISE.
FORECAST SOUNDS SHOW A DEEP MIXED LAYER UP TO ROUGHLY 550 MB BY
THIS AFTERNOON...WITH WINDS THRU THE MIXED LAYER MAXING OUT AT 20
TO 25 KTS OVER THE MOUNTAINS AND EAST CENTRAL WYOMING...AND 10 TO
15 KTS TO THE LEE OF THE LARAMIE RANGE AND POINTS EAST.
THEREFORE...EXPECT GUSTY WINDS TO PERSIST THRU THE AFTERNOON
WITHIN A CORRIDOR FROM CARBON COUNTY TO CONVERSE/NIOBRARA COUNTIES
WHILE WINDS SHOULD DIMINISH WITHIN THE DEEPENING LEESIDE TROUGH
ACROSS EXTREME SOUTHEAST WYOMING AND THE WESTERN NEBRASKA
PANHANDLE. HOT TEMPS WILL OCCUR TODAY WITH 80S AND 90S ACROSS
SOUTHEAST WYOMING AND 90S AND PERHAPS A FEW 100 DEGREE READINGS
IN THE PANHANDLE WITH THE THERMAL RIDGE OVERHEAD. A FETCH OF
SUBTROPICAL MOISTURE WILL ADVECT UP AND INTO THE CWA TODAY AS WELL
AND WILL KEEP HUMIDITIES IN THE UPPER TEENS TO LOW 20S ALONG AND
WEST OF THE LARAMIE RANGE WITH MID TO UPPER TEENS ACROSS THE
PLAINS. STILL LOOKING AT THE BEST JUXTAPOSITION OF LOW HUMIDITIES
AND GUSTY WINDS EARLY THIS AFTERNOON ACROSS FWZ 301 SO WILL KEEP
THE RED FLAG WARNING IN PLACE HERE. WINDS SHOULD BE ON THE
DOWNWARD TURN FURTHER SOUTH AND EAST WHEN HUMIDITIES WILL BE AT
THEIR LOWEST SO LOOKING AT ONLY MARGINAL FIRE WEATHER CONCERNS
HERE FOR ZONES 309 AND 310.

SHOWERS AND ISOLATED TSTMS WILL DEVELOP OVER THE MOUNTAINS THIS
AFTERNOON WITHIN THE DEEPEST MOISTURE AND AS WINDS ALOFT INCREASE
WITH THE APPROACHING SHORTWAVE. STILL THINKING SOME OF THIS
ACTIVITY WILL SHIFT TO THE PLAINS THRU THE LATE AFTERNOON AND
EVENING AS THE MOISTURE PLUME CONTINUES TO OVERSPREAD THE CWA.
GUIDANCE CONTINUES TO SHOW ENOUGH MOISTURE TO PRODUCE MODEST
RAINFALL WITH MUCH OF THE ACTIVITY...AND INVERTED-V PROFILES
SUGGEST GUSTY AND ERRATIC WINDS ARE A HIGH LIKELIHOOD AS WELL.

WINDS TONIGHT COULD REMAIN A BIT BREEZY AHEAD OF THE COLD FRONT
THAT IS STILL PROGGED TO DROP SOUTH ACROSS THE REGION STARTING
AROUND SUNRISE ON MONDAY. COOLER TEMPS ARE EXPECTED FOR MONDAY
WITH INCREASING MOISTURE AND UPSLOPE FLOW PROGGED THRU THE
AFTERNOON ACROSS THE PLAINS. A WEAK DISTURBANCE MOVING OVERHEAD IN
SOUTHWEST FLOW SHOULD SPARK OFF MORE AFTERNOON TSTMS IN THE HIGH
COUNTRY AIDED BY STRENGTHENING UPSLOPE FLOW. ADDITIONAL WEAK
VORTICITY AND MOISTURE MOVING OVERHEAD ON THE NOSE OF A JETLET
APPROACHING FROM THE SOUTHWEST ON TUESDAY WILL BRING ANOTHER
ROUND OF SHOWERS/TSTMS TO THE CWA IN THE AFTERNOON.

.LONG TERM...(WEDNESDAY THROUGH SATURDAY)
ISSUED AT 405 AM MDT SUN AUG 30 2015

WE REMAIN UNDER A BROAD SOUTHWESTERLY FLOW ALOFT WEDNESDAY THROUGH
LATE WEEK AS A AMPLIFYING UPPER TROUGH OVER THE PACIFIC NORTHWEST
STARTS TO MOVE EASTWARD. WITH FAIRLY DRY DEEP LAYERED AIRMASS WE
SHOULD SEE LITTLE IN THE WAY OF POPS EXCEPT FOR MAYBE A FEW
ISOLATED AFTERNOON/EVENING STORMS IN THE MOUNTAINS OF SE
WYOMING...MAINLY ON WEDNESDAY. BY THE WEEKEND WE WILL SEE SEVERAL
STRONGER MIDLEVEL IMPULSES MOVE THROUGH THE INCREASING
SOUTHWESTERLY FLOW ALOFT AS THE UPPER TROUGH TO THE NORTHWEST
STARTS TO EJECT OUT TO THE EAST...AND THIS IS EXPECTED TO BRING A
WEAK COLD FRONT DOWN FROM THE NORTHWEST HANGING IT UP ALONG THE
LARAMIE RANGE ON SATURDAY. THIS MAY FOCUS SOME ISOLATED TO
SCATTERED AFTERNOON/EVENING THUNDERSTORMS OVER THE EASTERN HALF OF
THE FORECAST AREA SATURDAY AFTERNOON AND EVENING.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 537 AM MDT SUN AUG 30 2015

AXIS OF DEEPER MIDLEVEL PACIFIC MOISTURE BEING PULLED NORTHWARD
ALONG THE SOUTHERN STREAM JETSTREAK FROM SOUTHERN CALIFORNIA TO
MONTANA MOVING GRADUALLY EASTWARD INTO OUR WESTERN ZONES THIS
MORNING. THIS WILL RESULT IN THE DEVELOPMENT OF SCATTERED
THUNDERSTORMS AROUND RAWLINS AND LARAMIE THIS AFTERNOON SO HAVE
ADDED VCTS MENTION BY MID AFTERNOON FOR THOSE AIRPORTS...THEN AT
CHEYENNE BY EARLY EVENING WITH NO MENTION FARTHER EAST DUE TO THE
MORE ISOLATED COVERAGE OF STORMS AS THEY MOVE OUT ONTO THE PLAINS
BEFORE DIMINISHING. MOSTLY HIGH CIRRUS AT ALL AIRPORTS THIS
MORNING WITH SOUTHWESTERLY WINDS INCREASING BY LATE MORNING EXCEPT
MORE SOUTHERLY IN THE NEBRASKA PANHANDLE THROUGH THE AFTERNOON.

&&

.FIRE WEATHER...
ISSUED AT 405 AM MDT SUN AUG 30 2015

HOT AND RELATIVELY DRY CONDITIONS ARE EXPECTED TODAY OVER MUCH OF
THE DISTRICT...WITH BREEZY WINDS THIS MORNING CONTINUING THROUGH
THE AFTERNOON IN THE HIGH COUNTRY AND FOR CONVERSE/NIOBRARA
COUNTIES. WINDS LOOK TO DIMINISH ALONG AND EAST OF THE LARAMIE
RANGE AFTER NOON TODAY. THE RED FLAG WARNING REMAINS IN EFFECT
FOR FWZ 301 FOR THE COMBINATION OF DRY AND BREEZY CONDITIONS.
INCREASING MOISTURE LATER THIS MORNING AND AFTERNOON WILL GIVE
CHANCES FOR WETTING RAINS MAINLY OVER THE MOUNTAINS AND PLAINS OF
SOUTHEAST WYOMING. CHANCES FOR RAIN WILL CONTINUE OVER THE
MOUNTAINS AND SOUTHERN WYO PLAINS THRU TUESDAY.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...RED FLAG WARNING FROM 11 AM THIS MORNING TO 7 PM MDT THIS
     EVENING FOR WYZ301.

NE...NONE.
&&

$$

SHORT TERM...RJM
LONG TERM...JG
AVIATION...JG
FIRE WEATHER...RJM



000
FXUS65 KCYS 301137 AAA
AFDCYS

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE CHEYENNE WY
537 AM MDT SUN AUG 30 2015

.UPDATE...FOR THE 6 AM AVIATION FORECAST PACKAGE UPDATE.

&&

.SHORT TERM...(TODAY THROUGH TUESDAY NIGHT)
ISSUED AT 405 AM MDT SUN AUG 30 2015

SOME HIGH CLOUDS ARE MOVING OVERHEAD EARLY THIS MORNING WITH SOUTH-
SOUTHWEST WINDS ON AVERAGE OF 5 TO 15 MPH OBSERVED AT MANY
LOCATIONS. THE NEAR SFC INVERSION SEEMS TO BE STRONG ENOUGH TO KEEP
THE GUSTY LLVL JET WINDS AT BAY THO SO SHOULD SEE THESE LIGHTER
WINDS PERSIST THRU THE MORNING.

THE LEESIDE PRESSURE TROUGH WILL DEEPEN THIS MORNING AS A STRONG
UPPER LEVEL SHORTWAVE MOVES ACROSS THE PAC NW AND NORTHERN
ROCKIES TODAY. WEST-SOUTHWEST SFC WINDS ARE EXPECTED TO INCREASE
AS THIS OCCURS AND AS THE INVERSION BEGINS TO LIFT AFTER SUNRISE.
FORECAST SOUNDS SHOW A DEEP MIXED LAYER UP TO ROUGHLY 550 MB BY
THIS AFTERNOON...WITH WINDS THRU THE MIXED LAYER MAXING OUT AT 20
TO 25 KTS OVER THE MOUNTAINS AND EAST CENTRAL WYOMING...AND 10 TO
15 KTS TO THE LEE OF THE LARAMIE RANGE AND POINTS EAST.
THEREFORE...EXPECT GUSTY WINDS TO PERSIST THRU THE AFTERNOON
WITHIN A CORRIDOR FROM CARBON COUNTY TO CONVERSE/NIOBRARA COUNTIES
WHILE WINDS SHOULD DIMINISH WITHIN THE DEEPENING LEESIDE TROUGH
ACROSS EXTREME SOUTHEAST WYOMING AND THE WESTERN NEBRASKA
PANHANDLE. HOT TEMPS WILL OCCUR TODAY WITH 80S AND 90S ACROSS
SOUTHEAST WYOMING AND 90S AND PERHAPS A FEW 100 DEGREE READINGS
IN THE PANHANDLE WITH THE THERMAL RIDGE OVERHEAD. A FETCH OF
SUBTROPICAL MOISTURE WILL ADVECT UP AND INTO THE CWA TODAY AS WELL
AND WILL KEEP HUMIDITIES IN THE UPPER TEENS TO LOW 20S ALONG AND
WEST OF THE LARAMIE RANGE WITH MID TO UPPER TEENS ACROSS THE
PLAINS. STILL LOOKING AT THE BEST JUXTAPOSITION OF LOW HUMIDITIES
AND GUSTY WINDS EARLY THIS AFTERNOON ACROSS FWZ 301 SO WILL KEEP
THE RED FLAG WARNING IN PLACE HERE. WINDS SHOULD BE ON THE
DOWNWARD TURN FURTHER SOUTH AND EAST WHEN HUMIDITIES WILL BE AT
THEIR LOWEST SO LOOKING AT ONLY MARGINAL FIRE WEATHER CONCERNS
HERE FOR ZONES 309 AND 310.

SHOWERS AND ISOLATED TSTMS WILL DEVELOP OVER THE MOUNTAINS THIS
AFTERNOON WITHIN THE DEEPEST MOISTURE AND AS WINDS ALOFT INCREASE
WITH THE APPROACHING SHORTWAVE. STILL THINKING SOME OF THIS
ACTIVITY WILL SHIFT TO THE PLAINS THRU THE LATE AFTERNOON AND
EVENING AS THE MOISTURE PLUME CONTINUES TO OVERSPREAD THE CWA.
GUIDANCE CONTINUES TO SHOW ENOUGH MOISTURE TO PRODUCE MODEST
RAINFALL WITH MUCH OF THE ACTIVITY...AND INVERTED-V PROFILES
SUGGEST GUSTY AND ERRATIC WINDS ARE A HIGH LIKELIHOOD AS WELL.

WINDS TONIGHT COULD REMAIN A BIT BREEZY AHEAD OF THE COLD FRONT
THAT IS STILL PROGGED TO DROP SOUTH ACROSS THE REGION STARTING
AROUND SUNRISE ON MONDAY. COOLER TEMPS ARE EXPECTED FOR MONDAY
WITH INCREASING MOISTURE AND UPSLOPE FLOW PROGGED THRU THE
AFTERNOON ACROSS THE PLAINS. A WEAK DISTURBANCE MOVING OVERHEAD IN
SOUTHWEST FLOW SHOULD SPARK OFF MORE AFTERNOON TSTMS IN THE HIGH
COUNTRY AIDED BY STRENGTHENING UPSLOPE FLOW. ADDITIONAL WEAK
VORTICITY AND MOISTURE MOVING OVERHEAD ON THE NOSE OF A JETLET
APPROACHING FROM THE SOUTHWEST ON TUESDAY WILL BRING ANOTHER
ROUND OF SHOWERS/TSTMS TO THE CWA IN THE AFTERNOON.

.LONG TERM...(WEDNESDAY THROUGH SATURDAY)
ISSUED AT 405 AM MDT SUN AUG 30 2015

WE REMAIN UNDER A BROAD SOUTHWESTERLY FLOW ALOFT WEDNESDAY THROUGH
LATE WEEK AS A AMPLIFYING UPPER TROUGH OVER THE PACIFIC NORTHWEST
STARTS TO MOVE EASTWARD. WITH FAIRLY DRY DEEP LAYERED AIRMASS WE
SHOULD SEE LITTLE IN THE WAY OF POPS EXCEPT FOR MAYBE A FEW
ISOLATED AFTERNOON/EVENING STORMS IN THE MOUNTAINS OF SE
WYOMING...MAINLY ON WEDNESDAY. BY THE WEEKEND WE WILL SEE SEVERAL
STRONGER MIDLEVEL IMPULSES MOVE THROUGH THE INCREASING
SOUTHWESTERLY FLOW ALOFT AS THE UPPER TROUGH TO THE NORTHWEST
STARTS TO EJECT OUT TO THE EAST...AND THIS IS EXPECTED TO BRING A
WEAK COLD FRONT DOWN FROM THE NORTHWEST HANGING IT UP ALONG THE
LARAMIE RANGE ON SATURDAY. THIS MAY FOCUS SOME ISOLATED TO
SCATTERED AFTERNOON/EVENING THUNDERSTORMS OVER THE EASTERN HALF OF
THE FORECAST AREA SATURDAY AFTERNOON AND EVENING.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 537 AM MDT SUN AUG 30 2015

AXIS OF DEEPER MIDLEVEL PACIFIC MOISTURE BEING PULLED NORTHWARD
ALONG THE SOUTHERN STREAM JETSTREAK FROM SOUTHERN CALIFORNIA TO
MONTANA MOVING GRADUALLY EASTWARD INTO OUR WESTERN ZONES THIS
MORNING. THIS WILL RESULT IN THE DEVELOPMENT OF SCATTERED
THUNDERSTORMS AROUND RAWLINS AND LARAMIE THIS AFTERNOON SO HAVE
ADDED VCTS MENTION BY MID AFTERNOON FOR THOSE AIRPORTS...THEN AT
CHEYENNE BY EARLY EVENING WITH NO MENTION FARTHER EAST DUE TO THE
MORE ISOLATED COVERAGE OF STORMS AS THEY MOVE OUT ONTO THE PLAINS
BEFORE DIMINISHING. MOSTLY HIGH CIRRUS AT ALL AIRPORTS THIS
MORNING WITH SOUTHWESTERLY WINDS INCREASING BY LATE MORNING EXCEPT
MORE SOUTHERLY IN THE NEBRASKA PANHANDLE THROUGH THE AFTERNOON.

&&

.FIRE WEATHER...
ISSUED AT 405 AM MDT SUN AUG 30 2015

HOT AND RELATIVELY DRY CONDITIONS ARE EXPECTED TODAY OVER MUCH OF
THE DISTRICT...WITH BREEZY WINDS THIS MORNING CONTINUING THROUGH
THE AFTERNOON IN THE HIGH COUNTRY AND FOR CONVERSE/NIOBRARA
COUNTIES. WINDS LOOK TO DIMINISH ALONG AND EAST OF THE LARAMIE
RANGE AFTER NOON TODAY. THE RED FLAG WARNING REMAINS IN EFFECT
FOR FWZ 301 FOR THE COMBINATION OF DRY AND BREEZY CONDITIONS.
INCREASING MOISTURE LATER THIS MORNING AND AFTERNOON WILL GIVE
CHANCES FOR WETTING RAINS MAINLY OVER THE MOUNTAINS AND PLAINS OF
SOUTHEAST WYOMING. CHANCES FOR RAIN WILL CONTINUE OVER THE
MOUNTAINS AND SOUTHERN WYO PLAINS THRU TUESDAY.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...RED FLAG WARNING FROM 11 AM THIS MORNING TO 7 PM MDT THIS
     EVENING FOR WYZ301.

NE...NONE.
&&

$$

SHORT TERM...RJM
LONG TERM...JG
AVIATION...JG
FIRE WEATHER...RJM



000
FXUS65 KCYS 301137 AAA
AFDCYS

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE CHEYENNE WY
537 AM MDT SUN AUG 30 2015

.UPDATE...FOR THE 6 AM AVIATION FORECAST PACKAGE UPDATE.

&&

.SHORT TERM...(TODAY THROUGH TUESDAY NIGHT)
ISSUED AT 405 AM MDT SUN AUG 30 2015

SOME HIGH CLOUDS ARE MOVING OVERHEAD EARLY THIS MORNING WITH SOUTH-
SOUTHWEST WINDS ON AVERAGE OF 5 TO 15 MPH OBSERVED AT MANY
LOCATIONS. THE NEAR SFC INVERSION SEEMS TO BE STRONG ENOUGH TO KEEP
THE GUSTY LLVL JET WINDS AT BAY THO SO SHOULD SEE THESE LIGHTER
WINDS PERSIST THRU THE MORNING.

THE LEESIDE PRESSURE TROUGH WILL DEEPEN THIS MORNING AS A STRONG
UPPER LEVEL SHORTWAVE MOVES ACROSS THE PAC NW AND NORTHERN
ROCKIES TODAY. WEST-SOUTHWEST SFC WINDS ARE EXPECTED TO INCREASE
AS THIS OCCURS AND AS THE INVERSION BEGINS TO LIFT AFTER SUNRISE.
FORECAST SOUNDS SHOW A DEEP MIXED LAYER UP TO ROUGHLY 550 MB BY
THIS AFTERNOON...WITH WINDS THRU THE MIXED LAYER MAXING OUT AT 20
TO 25 KTS OVER THE MOUNTAINS AND EAST CENTRAL WYOMING...AND 10 TO
15 KTS TO THE LEE OF THE LARAMIE RANGE AND POINTS EAST.
THEREFORE...EXPECT GUSTY WINDS TO PERSIST THRU THE AFTERNOON
WITHIN A CORRIDOR FROM CARBON COUNTY TO CONVERSE/NIOBRARA COUNTIES
WHILE WINDS SHOULD DIMINISH WITHIN THE DEEPENING LEESIDE TROUGH
ACROSS EXTREME SOUTHEAST WYOMING AND THE WESTERN NEBRASKA
PANHANDLE. HOT TEMPS WILL OCCUR TODAY WITH 80S AND 90S ACROSS
SOUTHEAST WYOMING AND 90S AND PERHAPS A FEW 100 DEGREE READINGS
IN THE PANHANDLE WITH THE THERMAL RIDGE OVERHEAD. A FETCH OF
SUBTROPICAL MOISTURE WILL ADVECT UP AND INTO THE CWA TODAY AS WELL
AND WILL KEEP HUMIDITIES IN THE UPPER TEENS TO LOW 20S ALONG AND
WEST OF THE LARAMIE RANGE WITH MID TO UPPER TEENS ACROSS THE
PLAINS. STILL LOOKING AT THE BEST JUXTAPOSITION OF LOW HUMIDITIES
AND GUSTY WINDS EARLY THIS AFTERNOON ACROSS FWZ 301 SO WILL KEEP
THE RED FLAG WARNING IN PLACE HERE. WINDS SHOULD BE ON THE
DOWNWARD TURN FURTHER SOUTH AND EAST WHEN HUMIDITIES WILL BE AT
THEIR LOWEST SO LOOKING AT ONLY MARGINAL FIRE WEATHER CONCERNS
HERE FOR ZONES 309 AND 310.

SHOWERS AND ISOLATED TSTMS WILL DEVELOP OVER THE MOUNTAINS THIS
AFTERNOON WITHIN THE DEEPEST MOISTURE AND AS WINDS ALOFT INCREASE
WITH THE APPROACHING SHORTWAVE. STILL THINKING SOME OF THIS
ACTIVITY WILL SHIFT TO THE PLAINS THRU THE LATE AFTERNOON AND
EVENING AS THE MOISTURE PLUME CONTINUES TO OVERSPREAD THE CWA.
GUIDANCE CONTINUES TO SHOW ENOUGH MOISTURE TO PRODUCE MODEST
RAINFALL WITH MUCH OF THE ACTIVITY...AND INVERTED-V PROFILES
SUGGEST GUSTY AND ERRATIC WINDS ARE A HIGH LIKELIHOOD AS WELL.

WINDS TONIGHT COULD REMAIN A BIT BREEZY AHEAD OF THE COLD FRONT
THAT IS STILL PROGGED TO DROP SOUTH ACROSS THE REGION STARTING
AROUND SUNRISE ON MONDAY. COOLER TEMPS ARE EXPECTED FOR MONDAY
WITH INCREASING MOISTURE AND UPSLOPE FLOW PROGGED THRU THE
AFTERNOON ACROSS THE PLAINS. A WEAK DISTURBANCE MOVING OVERHEAD IN
SOUTHWEST FLOW SHOULD SPARK OFF MORE AFTERNOON TSTMS IN THE HIGH
COUNTRY AIDED BY STRENGTHENING UPSLOPE FLOW. ADDITIONAL WEAK
VORTICITY AND MOISTURE MOVING OVERHEAD ON THE NOSE OF A JETLET
APPROACHING FROM THE SOUTHWEST ON TUESDAY WILL BRING ANOTHER
ROUND OF SHOWERS/TSTMS TO THE CWA IN THE AFTERNOON.

.LONG TERM...(WEDNESDAY THROUGH SATURDAY)
ISSUED AT 405 AM MDT SUN AUG 30 2015

WE REMAIN UNDER A BROAD SOUTHWESTERLY FLOW ALOFT WEDNESDAY THROUGH
LATE WEEK AS A AMPLIFYING UPPER TROUGH OVER THE PACIFIC NORTHWEST
STARTS TO MOVE EASTWARD. WITH FAIRLY DRY DEEP LAYERED AIRMASS WE
SHOULD SEE LITTLE IN THE WAY OF POPS EXCEPT FOR MAYBE A FEW
ISOLATED AFTERNOON/EVENING STORMS IN THE MOUNTAINS OF SE
WYOMING...MAINLY ON WEDNESDAY. BY THE WEEKEND WE WILL SEE SEVERAL
STRONGER MIDLEVEL IMPULSES MOVE THROUGH THE INCREASING
SOUTHWESTERLY FLOW ALOFT AS THE UPPER TROUGH TO THE NORTHWEST
STARTS TO EJECT OUT TO THE EAST...AND THIS IS EXPECTED TO BRING A
WEAK COLD FRONT DOWN FROM THE NORTHWEST HANGING IT UP ALONG THE
LARAMIE RANGE ON SATURDAY. THIS MAY FOCUS SOME ISOLATED TO
SCATTERED AFTERNOON/EVENING THUNDERSTORMS OVER THE EASTERN HALF OF
THE FORECAST AREA SATURDAY AFTERNOON AND EVENING.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 537 AM MDT SUN AUG 30 2015

AXIS OF DEEPER MIDLEVEL PACIFIC MOISTURE BEING PULLED NORTHWARD
ALONG THE SOUTHERN STREAM JETSTREAK FROM SOUTHERN CALIFORNIA TO
MONTANA MOVING GRADUALLY EASTWARD INTO OUR WESTERN ZONES THIS
MORNING. THIS WILL RESULT IN THE DEVELOPMENT OF SCATTERED
THUNDERSTORMS AROUND RAWLINS AND LARAMIE THIS AFTERNOON SO HAVE
ADDED VCTS MENTION BY MID AFTERNOON FOR THOSE AIRPORTS...THEN AT
CHEYENNE BY EARLY EVENING WITH NO MENTION FARTHER EAST DUE TO THE
MORE ISOLATED COVERAGE OF STORMS AS THEY MOVE OUT ONTO THE PLAINS
BEFORE DIMINISHING. MOSTLY HIGH CIRRUS AT ALL AIRPORTS THIS
MORNING WITH SOUTHWESTERLY WINDS INCREASING BY LATE MORNING EXCEPT
MORE SOUTHERLY IN THE NEBRASKA PANHANDLE THROUGH THE AFTERNOON.

&&

.FIRE WEATHER...
ISSUED AT 405 AM MDT SUN AUG 30 2015

HOT AND RELATIVELY DRY CONDITIONS ARE EXPECTED TODAY OVER MUCH OF
THE DISTRICT...WITH BREEZY WINDS THIS MORNING CONTINUING THROUGH
THE AFTERNOON IN THE HIGH COUNTRY AND FOR CONVERSE/NIOBRARA
COUNTIES. WINDS LOOK TO DIMINISH ALONG AND EAST OF THE LARAMIE
RANGE AFTER NOON TODAY. THE RED FLAG WARNING REMAINS IN EFFECT
FOR FWZ 301 FOR THE COMBINATION OF DRY AND BREEZY CONDITIONS.
INCREASING MOISTURE LATER THIS MORNING AND AFTERNOON WILL GIVE
CHANCES FOR WETTING RAINS MAINLY OVER THE MOUNTAINS AND PLAINS OF
SOUTHEAST WYOMING. CHANCES FOR RAIN WILL CONTINUE OVER THE
MOUNTAINS AND SOUTHERN WYO PLAINS THRU TUESDAY.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...RED FLAG WARNING FROM 11 AM THIS MORNING TO 7 PM MDT THIS
     EVENING FOR WYZ301.

NE...NONE.
&&

$$

SHORT TERM...RJM
LONG TERM...JG
AVIATION...JG
FIRE WEATHER...RJM



000
FXUS65 KCYS 301006
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
406 AM MDT SUN AUG 30 2015

.SHORT TERM...(TODAY THROUGH TUESDAY NIGHT)
ISSUED AT 405 AM MDT SUN AUG 30 2015

SOME HIGH CLOUDS ARE MOVING OVERHEAD EARLY THIS MORNING WITH SOUTH-
SOUTHWEST WINDS ON AVERAGE OF 5 TO 15 MPH OBSERVED AT MANY
LOCATIONS. THE NEAR SFC INVERSION SEEMS TO BE STRONG ENOUGH TO KEEP
THE GUSTY LLVL JET WINDS AT BAY THO SO SHOULD SEE THESE LIGHTER
WINDS PERSIST THRU THE MORNING.

THE LEESIDE PRESSURE TROUGH WILL DEEPEN THIS MORNING AS A STRONG
UPPER LEVEL SHORTWAVE MOVES ACROSS THE PAC NW AND NORTHERN
ROCKIES TODAY. WEST-SOUTHWEST SFC WINDS ARE EXPECTED TO INCREASE
AS THIS OCCURS AND AS THE INVERSION BEGINS TO LIFT AFTER SUNRISE.
FORECAST SOUNDS SHOW A DEEP MIXED LAYER UP TO ROUGHLY 550 MB BY
THIS AFTERNOON...WITH WINDS THRU THE MIXED LAYER MAXING OUT AT 20
TO 25 KTS OVER THE MOUNTAINS AND EAST CENTRAL WYOMING...AND 10 TO
15 KTS TO THE LEE OF THE LARAMIE RANGE AND POINTS EAST.
THEREFORE...EXPECT GUSTY WINDS TO PERSIST THRU THE AFTERNOON
WITHIN A CORRIDOR FROM CARBON COUNTY TO CONVERSE/NIOBRARA COUNTIES
WHILE WINDS SHOULD DIMINISH WITHIN THE DEEPENING LEESIDE TROUGH
ACROSS EXTREME SOUTHEAST WYOMING AND THE WESTERN NEBRASKA
PANHANDLE. HOT TEMPS WILL OCCUR TODAY WITH 80S AND 90S ACROSS
SOUTHEAST WYOMING AND 90S AND PERHAPS A FEW 100 DEGREE READINGS
IN THE PANHANDLE WITH THE THERMAL RIDGE OVERHEAD. A FETCH OF
SUBTROPICAL MOISTURE WILL ADVECT UP AND INTO THE CWA TODAY AS WELL
AND WILL KEEP HUMIDITIES IN THE UPPER TEENS TO LOW 20S ALONG AND
WEST OF THE LARAMIE RANGE WITH MID TO UPPER TEENS ACROSS THE
PLAINS. STILL LOOKING AT THE BEST JUXTAPOSITION OF LOW HUMIDITIES
AND GUSTY WINDS EARLY THIS AFTERNOON ACROSS FWZ 301 SO WILL KEEP
THE RED FLAG WARNING IN PLACE HERE. WINDS SHOULD BE ON THE
DOWNWARD TURN FURTHER SOUTH AND EAST WHEN HUMIDITIES WILL BE AT
THEIR LOWEST SO LOOKING AT ONLY MARGINAL FIRE WEATHER CONCERNS
HERE FOR ZONES 309 AND 310.

SHOWERS AND ISOLATED TSTMS WILL DEVELOP OVER THE MOUNTAINS THIS
AFTERNOON WITHIN THE DEEPEST MOISTURE AND AS WINDS ALOFT INCREASE
WITH THE APPROACHING SHORTWAVE. STILL THINKING SOME OF THIS
ACTIVITY WILL SHIFT TO THE PLAINS THRU THE LATE AFTERNOON AND
EVENING AS THE MOISTURE PLUME CONTINUES TO OVERSPREAD THE CWA.
GUIDANCE CONTINUES TO SHOW ENOUGH MOISTURE TO PRODUCE MODEST
RAINFALL WITH MUCH OF THE ACTIVITY...AND INVERTED-V PROFILES
SUGGEST GUSTY AND ERRATIC WINDS ARE A HIGH LIKELIHOOD AS WELL.

WINDS TONIGHT COULD REMAIN A BIT BREEZY AHEAD OF THE COLD FRONT
THAT IS STILL PROGGED TO DROP SOUTH ACROSS THE REGION STARTING
AROUND SUNRISE ON MONDAY. COOLER TEMPS ARE EXPECTED FOR MONDAY
WITH INCREASING MOISTURE AND UPSLOPE FLOW PROGGED THRU THE
AFTERNOON ACROSS THE PLAINS. A WEAK DISTURBANCE MOVING OVERHEAD IN
SOUTHWEST FLOW SHOULD SPARK OFF MORE AFTERNOON TSTMS IN THE HIGH
COUNTRY AIDED BY STRENGTHENING UPSLOPE FLOW. ADDITIONAL WEAK
VORTICITY AND MOISTURE MOVING OVERHEAD ON THE NOSE OF A JETLET
APPROACHING FROM THE SOUTHWEST ON TUESDAY WILL BRING ANOTHER
ROUND OF SHOWERS/TSTMS TO THE CWA IN THE AFTERNOON.

.LONG TERM...(WEDNESDAY THROUGH SATURDAY)
ISSUED AT 405 AM MDT SUN AUG 30 2015

WE REMAIN UNDER A BROAD SOUTHWESTERLY FLOW ALOFT WEDNESDAY THROUGH
LATE WEEK AS A AMPLIFYING UPPER TROUGH OVER THE PACIFIC NORTHWEST
STARTS TO MOVE EASTWARD. WITH FAIRLY DRY DEEP LAYERED AIRMASS WE
SHOULD SEE LITTLE IN THE WAY OF POPS EXCEPT FOR MAYBE A FEW
ISOLATED AFTERNOON/EVENING STORMS IN THE MOUNTAINS OF SE
WYOMING...MAINLY ON WEDNESDAY. BY THE WEEKEND WE WILL SEE SEVERAL
STRONGER MIDLEVEL IMPULSES MOVE THROUGH THE INCREASING
SOUTHWESTERLY FLOW ALOFT AS THE UPPER TROUGH TO THE NORTHWEST
STARTS TO EJECT OUT TO THE EAST...AND THIS IS EXPECTED TO BRING A
WEAK COLD FRONT DOWN FROM THE NORTHWEST HANGING IT UP ALONG THE
LARAMIE RANGE ON SATURDAY. THIS MAY FOCUS SOME ISOLATED TO
SCATTERED AFTERNOON/EVENING THUNDERSTORMS OVER THE EASTERN HALF OF
THE FORECAST AREA SATURDAY AFTERNOON AND EVENING.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1134 PM MDT SAT AUG 29 2015

NO SIGNIFICANT AVIATION FORECAST CONCERNS OVERNIGHT. LIGHT TO
MODERATE SOUTHEASTERLY SURFACE WINDS WILL GRADUALLY VEER TO MORE
SOUTHWESTERLY THROUGH MID MORNING WITH A FEW PASSING HIGH LEVEL
CIRRUS CLOUDS OVERNIGHT. WINDS SHOULD PICK UP A BIT INTO THE 15-25
KT RANGE FROM THE SOUTHWEST FOR SOME SITES BY 17Z. IN SHORT VFR
CONDITIONS EXPECTED ALL SITES NEXT 24 HOURS.

&&

.FIRE WEATHER...
ISSUED AT 405 AM MDT SUN AUG 30 2015

HOT AND RELATIVELY DRY CONDITIONS ARE EXPECTED TODAY OVER MUCH OF
THE DISTRICT...WITH BREEZY WINDS THIS MORNING CONTINUING THROUGH
THE AFTERNOON IN THE HIGH COUNTRY AND FOR CONVERSE/NIOBRARA
COUNTIES. WINDS LOOK TO DIMINISH ALONG AND EAST OF THE LARAMIE
RANGE AFTER NOON TODAY. THE RED FLAG WARNING REMAINS IN EFFECT
FOR FWZ 301 FOR THE COMBINATION OF DRY AND BREEZY CONDITIONS.
INCREASING MOISTURE LATER THIS MORNING AND AFTERNOON WILL GIVE
CHANCES FOR WETTING RAINS MAINLY OVER THE MOUNTAINS AND PLAINS OF
SOUTHEAST WYOMING. CHANCES FOR RAIN WILL CONTINUE OVER THE
MOUNTAINS AND SOUTHERN WYO PLAINS THRU TUESDAY.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...RED FLAG WARNING FROM 11 AM THIS MORNING TO 7 PM MDT THIS
     EVENING FOR WYZ301.

NE...NONE.
&&

$$

SHORT TERM...RJM
LONG TERM...JG
AVIATION...JG
FIRE WEATHER...RJM




000
FXUS65 KCYS 301006
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
406 AM MDT SUN AUG 30 2015

.SHORT TERM...(TODAY THROUGH TUESDAY NIGHT)
ISSUED AT 405 AM MDT SUN AUG 30 2015

SOME HIGH CLOUDS ARE MOVING OVERHEAD EARLY THIS MORNING WITH SOUTH-
SOUTHWEST WINDS ON AVERAGE OF 5 TO 15 MPH OBSERVED AT MANY
LOCATIONS. THE NEAR SFC INVERSION SEEMS TO BE STRONG ENOUGH TO KEEP
THE GUSTY LLVL JET WINDS AT BAY THO SO SHOULD SEE THESE LIGHTER
WINDS PERSIST THRU THE MORNING.

THE LEESIDE PRESSURE TROUGH WILL DEEPEN THIS MORNING AS A STRONG
UPPER LEVEL SHORTWAVE MOVES ACROSS THE PAC NW AND NORTHERN
ROCKIES TODAY. WEST-SOUTHWEST SFC WINDS ARE EXPECTED TO INCREASE
AS THIS OCCURS AND AS THE INVERSION BEGINS TO LIFT AFTER SUNRISE.
FORECAST SOUNDS SHOW A DEEP MIXED LAYER UP TO ROUGHLY 550 MB BY
THIS AFTERNOON...WITH WINDS THRU THE MIXED LAYER MAXING OUT AT 20
TO 25 KTS OVER THE MOUNTAINS AND EAST CENTRAL WYOMING...AND 10 TO
15 KTS TO THE LEE OF THE LARAMIE RANGE AND POINTS EAST.
THEREFORE...EXPECT GUSTY WINDS TO PERSIST THRU THE AFTERNOON
WITHIN A CORRIDOR FROM CARBON COUNTY TO CONVERSE/NIOBRARA COUNTIES
WHILE WINDS SHOULD DIMINISH WITHIN THE DEEPENING LEESIDE TROUGH
ACROSS EXTREME SOUTHEAST WYOMING AND THE WESTERN NEBRASKA
PANHANDLE. HOT TEMPS WILL OCCUR TODAY WITH 80S AND 90S ACROSS
SOUTHEAST WYOMING AND 90S AND PERHAPS A FEW 100 DEGREE READINGS
IN THE PANHANDLE WITH THE THERMAL RIDGE OVERHEAD. A FETCH OF
SUBTROPICAL MOISTURE WILL ADVECT UP AND INTO THE CWA TODAY AS WELL
AND WILL KEEP HUMIDITIES IN THE UPPER TEENS TO LOW 20S ALONG AND
WEST OF THE LARAMIE RANGE WITH MID TO UPPER TEENS ACROSS THE
PLAINS. STILL LOOKING AT THE BEST JUXTAPOSITION OF LOW HUMIDITIES
AND GUSTY WINDS EARLY THIS AFTERNOON ACROSS FWZ 301 SO WILL KEEP
THE RED FLAG WARNING IN PLACE HERE. WINDS SHOULD BE ON THE
DOWNWARD TURN FURTHER SOUTH AND EAST WHEN HUMIDITIES WILL BE AT
THEIR LOWEST SO LOOKING AT ONLY MARGINAL FIRE WEATHER CONCERNS
HERE FOR ZONES 309 AND 310.

SHOWERS AND ISOLATED TSTMS WILL DEVELOP OVER THE MOUNTAINS THIS
AFTERNOON WITHIN THE DEEPEST MOISTURE AND AS WINDS ALOFT INCREASE
WITH THE APPROACHING SHORTWAVE. STILL THINKING SOME OF THIS
ACTIVITY WILL SHIFT TO THE PLAINS THRU THE LATE AFTERNOON AND
EVENING AS THE MOISTURE PLUME CONTINUES TO OVERSPREAD THE CWA.
GUIDANCE CONTINUES TO SHOW ENOUGH MOISTURE TO PRODUCE MODEST
RAINFALL WITH MUCH OF THE ACTIVITY...AND INVERTED-V PROFILES
SUGGEST GUSTY AND ERRATIC WINDS ARE A HIGH LIKELIHOOD AS WELL.

WINDS TONIGHT COULD REMAIN A BIT BREEZY AHEAD OF THE COLD FRONT
THAT IS STILL PROGGED TO DROP SOUTH ACROSS THE REGION STARTING
AROUND SUNRISE ON MONDAY. COOLER TEMPS ARE EXPECTED FOR MONDAY
WITH INCREASING MOISTURE AND UPSLOPE FLOW PROGGED THRU THE
AFTERNOON ACROSS THE PLAINS. A WEAK DISTURBANCE MOVING OVERHEAD IN
SOUTHWEST FLOW SHOULD SPARK OFF MORE AFTERNOON TSTMS IN THE HIGH
COUNTRY AIDED BY STRENGTHENING UPSLOPE FLOW. ADDITIONAL WEAK
VORTICITY AND MOISTURE MOVING OVERHEAD ON THE NOSE OF A JETLET
APPROACHING FROM THE SOUTHWEST ON TUESDAY WILL BRING ANOTHER
ROUND OF SHOWERS/TSTMS TO THE CWA IN THE AFTERNOON.

.LONG TERM...(WEDNESDAY THROUGH SATURDAY)
ISSUED AT 405 AM MDT SUN AUG 30 2015

WE REMAIN UNDER A BROAD SOUTHWESTERLY FLOW ALOFT WEDNESDAY THROUGH
LATE WEEK AS A AMPLIFYING UPPER TROUGH OVER THE PACIFIC NORTHWEST
STARTS TO MOVE EASTWARD. WITH FAIRLY DRY DEEP LAYERED AIRMASS WE
SHOULD SEE LITTLE IN THE WAY OF POPS EXCEPT FOR MAYBE A FEW
ISOLATED AFTERNOON/EVENING STORMS IN THE MOUNTAINS OF SE
WYOMING...MAINLY ON WEDNESDAY. BY THE WEEKEND WE WILL SEE SEVERAL
STRONGER MIDLEVEL IMPULSES MOVE THROUGH THE INCREASING
SOUTHWESTERLY FLOW ALOFT AS THE UPPER TROUGH TO THE NORTHWEST
STARTS TO EJECT OUT TO THE EAST...AND THIS IS EXPECTED TO BRING A
WEAK COLD FRONT DOWN FROM THE NORTHWEST HANGING IT UP ALONG THE
LARAMIE RANGE ON SATURDAY. THIS MAY FOCUS SOME ISOLATED TO
SCATTERED AFTERNOON/EVENING THUNDERSTORMS OVER THE EASTERN HALF OF
THE FORECAST AREA SATURDAY AFTERNOON AND EVENING.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1134 PM MDT SAT AUG 29 2015

NO SIGNIFICANT AVIATION FORECAST CONCERNS OVERNIGHT. LIGHT TO
MODERATE SOUTHEASTERLY SURFACE WINDS WILL GRADUALLY VEER TO MORE
SOUTHWESTERLY THROUGH MID MORNING WITH A FEW PASSING HIGH LEVEL
CIRRUS CLOUDS OVERNIGHT. WINDS SHOULD PICK UP A BIT INTO THE 15-25
KT RANGE FROM THE SOUTHWEST FOR SOME SITES BY 17Z. IN SHORT VFR
CONDITIONS EXPECTED ALL SITES NEXT 24 HOURS.

&&

.FIRE WEATHER...
ISSUED AT 405 AM MDT SUN AUG 30 2015

HOT AND RELATIVELY DRY CONDITIONS ARE EXPECTED TODAY OVER MUCH OF
THE DISTRICT...WITH BREEZY WINDS THIS MORNING CONTINUING THROUGH
THE AFTERNOON IN THE HIGH COUNTRY AND FOR CONVERSE/NIOBRARA
COUNTIES. WINDS LOOK TO DIMINISH ALONG AND EAST OF THE LARAMIE
RANGE AFTER NOON TODAY. THE RED FLAG WARNING REMAINS IN EFFECT
FOR FWZ 301 FOR THE COMBINATION OF DRY AND BREEZY CONDITIONS.
INCREASING MOISTURE LATER THIS MORNING AND AFTERNOON WILL GIVE
CHANCES FOR WETTING RAINS MAINLY OVER THE MOUNTAINS AND PLAINS OF
SOUTHEAST WYOMING. CHANCES FOR RAIN WILL CONTINUE OVER THE
MOUNTAINS AND SOUTHERN WYO PLAINS THRU TUESDAY.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...RED FLAG WARNING FROM 11 AM THIS MORNING TO 7 PM MDT THIS
     EVENING FOR WYZ301.

NE...NONE.
&&

$$

SHORT TERM...RJM
LONG TERM...JG
AVIATION...JG
FIRE WEATHER...RJM



000
FXUS65 KCYS 301006
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
406 AM MDT SUN AUG 30 2015

.SHORT TERM...(TODAY THROUGH TUESDAY NIGHT)
ISSUED AT 405 AM MDT SUN AUG 30 2015

SOME HIGH CLOUDS ARE MOVING OVERHEAD EARLY THIS MORNING WITH SOUTH-
SOUTHWEST WINDS ON AVERAGE OF 5 TO 15 MPH OBSERVED AT MANY
LOCATIONS. THE NEAR SFC INVERSION SEEMS TO BE STRONG ENOUGH TO KEEP
THE GUSTY LLVL JET WINDS AT BAY THO SO SHOULD SEE THESE LIGHTER
WINDS PERSIST THRU THE MORNING.

THE LEESIDE PRESSURE TROUGH WILL DEEPEN THIS MORNING AS A STRONG
UPPER LEVEL SHORTWAVE MOVES ACROSS THE PAC NW AND NORTHERN
ROCKIES TODAY. WEST-SOUTHWEST SFC WINDS ARE EXPECTED TO INCREASE
AS THIS OCCURS AND AS THE INVERSION BEGINS TO LIFT AFTER SUNRISE.
FORECAST SOUNDS SHOW A DEEP MIXED LAYER UP TO ROUGHLY 550 MB BY
THIS AFTERNOON...WITH WINDS THRU THE MIXED LAYER MAXING OUT AT 20
TO 25 KTS OVER THE MOUNTAINS AND EAST CENTRAL WYOMING...AND 10 TO
15 KTS TO THE LEE OF THE LARAMIE RANGE AND POINTS EAST.
THEREFORE...EXPECT GUSTY WINDS TO PERSIST THRU THE AFTERNOON
WITHIN A CORRIDOR FROM CARBON COUNTY TO CONVERSE/NIOBRARA COUNTIES
WHILE WINDS SHOULD DIMINISH WITHIN THE DEEPENING LEESIDE TROUGH
ACROSS EXTREME SOUTHEAST WYOMING AND THE WESTERN NEBRASKA
PANHANDLE. HOT TEMPS WILL OCCUR TODAY WITH 80S AND 90S ACROSS
SOUTHEAST WYOMING AND 90S AND PERHAPS A FEW 100 DEGREE READINGS
IN THE PANHANDLE WITH THE THERMAL RIDGE OVERHEAD. A FETCH OF
SUBTROPICAL MOISTURE WILL ADVECT UP AND INTO THE CWA TODAY AS WELL
AND WILL KEEP HUMIDITIES IN THE UPPER TEENS TO LOW 20S ALONG AND
WEST OF THE LARAMIE RANGE WITH MID TO UPPER TEENS ACROSS THE
PLAINS. STILL LOOKING AT THE BEST JUXTAPOSITION OF LOW HUMIDITIES
AND GUSTY WINDS EARLY THIS AFTERNOON ACROSS FWZ 301 SO WILL KEEP
THE RED FLAG WARNING IN PLACE HERE. WINDS SHOULD BE ON THE
DOWNWARD TURN FURTHER SOUTH AND EAST WHEN HUMIDITIES WILL BE AT
THEIR LOWEST SO LOOKING AT ONLY MARGINAL FIRE WEATHER CONCERNS
HERE FOR ZONES 309 AND 310.

SHOWERS AND ISOLATED TSTMS WILL DEVELOP OVER THE MOUNTAINS THIS
AFTERNOON WITHIN THE DEEPEST MOISTURE AND AS WINDS ALOFT INCREASE
WITH THE APPROACHING SHORTWAVE. STILL THINKING SOME OF THIS
ACTIVITY WILL SHIFT TO THE PLAINS THRU THE LATE AFTERNOON AND
EVENING AS THE MOISTURE PLUME CONTINUES TO OVERSPREAD THE CWA.
GUIDANCE CONTINUES TO SHOW ENOUGH MOISTURE TO PRODUCE MODEST
RAINFALL WITH MUCH OF THE ACTIVITY...AND INVERTED-V PROFILES
SUGGEST GUSTY AND ERRATIC WINDS ARE A HIGH LIKELIHOOD AS WELL.

WINDS TONIGHT COULD REMAIN A BIT BREEZY AHEAD OF THE COLD FRONT
THAT IS STILL PROGGED TO DROP SOUTH ACROSS THE REGION STARTING
AROUND SUNRISE ON MONDAY. COOLER TEMPS ARE EXPECTED FOR MONDAY
WITH INCREASING MOISTURE AND UPSLOPE FLOW PROGGED THRU THE
AFTERNOON ACROSS THE PLAINS. A WEAK DISTURBANCE MOVING OVERHEAD IN
SOUTHWEST FLOW SHOULD SPARK OFF MORE AFTERNOON TSTMS IN THE HIGH
COUNTRY AIDED BY STRENGTHENING UPSLOPE FLOW. ADDITIONAL WEAK
VORTICITY AND MOISTURE MOVING OVERHEAD ON THE NOSE OF A JETLET
APPROACHING FROM THE SOUTHWEST ON TUESDAY WILL BRING ANOTHER
ROUND OF SHOWERS/TSTMS TO THE CWA IN THE AFTERNOON.

.LONG TERM...(WEDNESDAY THROUGH SATURDAY)
ISSUED AT 405 AM MDT SUN AUG 30 2015

WE REMAIN UNDER A BROAD SOUTHWESTERLY FLOW ALOFT WEDNESDAY THROUGH
LATE WEEK AS A AMPLIFYING UPPER TROUGH OVER THE PACIFIC NORTHWEST
STARTS TO MOVE EASTWARD. WITH FAIRLY DRY DEEP LAYERED AIRMASS WE
SHOULD SEE LITTLE IN THE WAY OF POPS EXCEPT FOR MAYBE A FEW
ISOLATED AFTERNOON/EVENING STORMS IN THE MOUNTAINS OF SE
WYOMING...MAINLY ON WEDNESDAY. BY THE WEEKEND WE WILL SEE SEVERAL
STRONGER MIDLEVEL IMPULSES MOVE THROUGH THE INCREASING
SOUTHWESTERLY FLOW ALOFT AS THE UPPER TROUGH TO THE NORTHWEST
STARTS TO EJECT OUT TO THE EAST...AND THIS IS EXPECTED TO BRING A
WEAK COLD FRONT DOWN FROM THE NORTHWEST HANGING IT UP ALONG THE
LARAMIE RANGE ON SATURDAY. THIS MAY FOCUS SOME ISOLATED TO
SCATTERED AFTERNOON/EVENING THUNDERSTORMS OVER THE EASTERN HALF OF
THE FORECAST AREA SATURDAY AFTERNOON AND EVENING.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1134 PM MDT SAT AUG 29 2015

NO SIGNIFICANT AVIATION FORECAST CONCERNS OVERNIGHT. LIGHT TO
MODERATE SOUTHEASTERLY SURFACE WINDS WILL GRADUALLY VEER TO MORE
SOUTHWESTERLY THROUGH MID MORNING WITH A FEW PASSING HIGH LEVEL
CIRRUS CLOUDS OVERNIGHT. WINDS SHOULD PICK UP A BIT INTO THE 15-25
KT RANGE FROM THE SOUTHWEST FOR SOME SITES BY 17Z. IN SHORT VFR
CONDITIONS EXPECTED ALL SITES NEXT 24 HOURS.

&&

.FIRE WEATHER...
ISSUED AT 405 AM MDT SUN AUG 30 2015

HOT AND RELATIVELY DRY CONDITIONS ARE EXPECTED TODAY OVER MUCH OF
THE DISTRICT...WITH BREEZY WINDS THIS MORNING CONTINUING THROUGH
THE AFTERNOON IN THE HIGH COUNTRY AND FOR CONVERSE/NIOBRARA
COUNTIES. WINDS LOOK TO DIMINISH ALONG AND EAST OF THE LARAMIE
RANGE AFTER NOON TODAY. THE RED FLAG WARNING REMAINS IN EFFECT
FOR FWZ 301 FOR THE COMBINATION OF DRY AND BREEZY CONDITIONS.
INCREASING MOISTURE LATER THIS MORNING AND AFTERNOON WILL GIVE
CHANCES FOR WETTING RAINS MAINLY OVER THE MOUNTAINS AND PLAINS OF
SOUTHEAST WYOMING. CHANCES FOR RAIN WILL CONTINUE OVER THE
MOUNTAINS AND SOUTHERN WYO PLAINS THRU TUESDAY.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...RED FLAG WARNING FROM 11 AM THIS MORNING TO 7 PM MDT THIS
     EVENING FOR WYZ301.

NE...NONE.
&&

$$

SHORT TERM...RJM
LONG TERM...JG
AVIATION...JG
FIRE WEATHER...RJM




000
FXUS65 KCYS 301006
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
406 AM MDT SUN AUG 30 2015

.SHORT TERM...(TODAY THROUGH TUESDAY NIGHT)
ISSUED AT 405 AM MDT SUN AUG 30 2015

SOME HIGH CLOUDS ARE MOVING OVERHEAD EARLY THIS MORNING WITH SOUTH-
SOUTHWEST WINDS ON AVERAGE OF 5 TO 15 MPH OBSERVED AT MANY
LOCATIONS. THE NEAR SFC INVERSION SEEMS TO BE STRONG ENOUGH TO KEEP
THE GUSTY LLVL JET WINDS AT BAY THO SO SHOULD SEE THESE LIGHTER
WINDS PERSIST THRU THE MORNING.

THE LEESIDE PRESSURE TROUGH WILL DEEPEN THIS MORNING AS A STRONG
UPPER LEVEL SHORTWAVE MOVES ACROSS THE PAC NW AND NORTHERN
ROCKIES TODAY. WEST-SOUTHWEST SFC WINDS ARE EXPECTED TO INCREASE
AS THIS OCCURS AND AS THE INVERSION BEGINS TO LIFT AFTER SUNRISE.
FORECAST SOUNDS SHOW A DEEP MIXED LAYER UP TO ROUGHLY 550 MB BY
THIS AFTERNOON...WITH WINDS THRU THE MIXED LAYER MAXING OUT AT 20
TO 25 KTS OVER THE MOUNTAINS AND EAST CENTRAL WYOMING...AND 10 TO
15 KTS TO THE LEE OF THE LARAMIE RANGE AND POINTS EAST.
THEREFORE...EXPECT GUSTY WINDS TO PERSIST THRU THE AFTERNOON
WITHIN A CORRIDOR FROM CARBON COUNTY TO CONVERSE/NIOBRARA COUNTIES
WHILE WINDS SHOULD DIMINISH WITHIN THE DEEPENING LEESIDE TROUGH
ACROSS EXTREME SOUTHEAST WYOMING AND THE WESTERN NEBRASKA
PANHANDLE. HOT TEMPS WILL OCCUR TODAY WITH 80S AND 90S ACROSS
SOUTHEAST WYOMING AND 90S AND PERHAPS A FEW 100 DEGREE READINGS
IN THE PANHANDLE WITH THE THERMAL RIDGE OVERHEAD. A FETCH OF
SUBTROPICAL MOISTURE WILL ADVECT UP AND INTO THE CWA TODAY AS WELL
AND WILL KEEP HUMIDITIES IN THE UPPER TEENS TO LOW 20S ALONG AND
WEST OF THE LARAMIE RANGE WITH MID TO UPPER TEENS ACROSS THE
PLAINS. STILL LOOKING AT THE BEST JUXTAPOSITION OF LOW HUMIDITIES
AND GUSTY WINDS EARLY THIS AFTERNOON ACROSS FWZ 301 SO WILL KEEP
THE RED FLAG WARNING IN PLACE HERE. WINDS SHOULD BE ON THE
DOWNWARD TURN FURTHER SOUTH AND EAST WHEN HUMIDITIES WILL BE AT
THEIR LOWEST SO LOOKING AT ONLY MARGINAL FIRE WEATHER CONCERNS
HERE FOR ZONES 309 AND 310.

SHOWERS AND ISOLATED TSTMS WILL DEVELOP OVER THE MOUNTAINS THIS
AFTERNOON WITHIN THE DEEPEST MOISTURE AND AS WINDS ALOFT INCREASE
WITH THE APPROACHING SHORTWAVE. STILL THINKING SOME OF THIS
ACTIVITY WILL SHIFT TO THE PLAINS THRU THE LATE AFTERNOON AND
EVENING AS THE MOISTURE PLUME CONTINUES TO OVERSPREAD THE CWA.
GUIDANCE CONTINUES TO SHOW ENOUGH MOISTURE TO PRODUCE MODEST
RAINFALL WITH MUCH OF THE ACTIVITY...AND INVERTED-V PROFILES
SUGGEST GUSTY AND ERRATIC WINDS ARE A HIGH LIKELIHOOD AS WELL.

WINDS TONIGHT COULD REMAIN A BIT BREEZY AHEAD OF THE COLD FRONT
THAT IS STILL PROGGED TO DROP SOUTH ACROSS THE REGION STARTING
AROUND SUNRISE ON MONDAY. COOLER TEMPS ARE EXPECTED FOR MONDAY
WITH INCREASING MOISTURE AND UPSLOPE FLOW PROGGED THRU THE
AFTERNOON ACROSS THE PLAINS. A WEAK DISTURBANCE MOVING OVERHEAD IN
SOUTHWEST FLOW SHOULD SPARK OFF MORE AFTERNOON TSTMS IN THE HIGH
COUNTRY AIDED BY STRENGTHENING UPSLOPE FLOW. ADDITIONAL WEAK
VORTICITY AND MOISTURE MOVING OVERHEAD ON THE NOSE OF A JETLET
APPROACHING FROM THE SOUTHWEST ON TUESDAY WILL BRING ANOTHER
ROUND OF SHOWERS/TSTMS TO THE CWA IN THE AFTERNOON.

.LONG TERM...(WEDNESDAY THROUGH SATURDAY)
ISSUED AT 405 AM MDT SUN AUG 30 2015

WE REMAIN UNDER A BROAD SOUTHWESTERLY FLOW ALOFT WEDNESDAY THROUGH
LATE WEEK AS A AMPLIFYING UPPER TROUGH OVER THE PACIFIC NORTHWEST
STARTS TO MOVE EASTWARD. WITH FAIRLY DRY DEEP LAYERED AIRMASS WE
SHOULD SEE LITTLE IN THE WAY OF POPS EXCEPT FOR MAYBE A FEW
ISOLATED AFTERNOON/EVENING STORMS IN THE MOUNTAINS OF SE
WYOMING...MAINLY ON WEDNESDAY. BY THE WEEKEND WE WILL SEE SEVERAL
STRONGER MIDLEVEL IMPULSES MOVE THROUGH THE INCREASING
SOUTHWESTERLY FLOW ALOFT AS THE UPPER TROUGH TO THE NORTHWEST
STARTS TO EJECT OUT TO THE EAST...AND THIS IS EXPECTED TO BRING A
WEAK COLD FRONT DOWN FROM THE NORTHWEST HANGING IT UP ALONG THE
LARAMIE RANGE ON SATURDAY. THIS MAY FOCUS SOME ISOLATED TO
SCATTERED AFTERNOON/EVENING THUNDERSTORMS OVER THE EASTERN HALF OF
THE FORECAST AREA SATURDAY AFTERNOON AND EVENING.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1134 PM MDT SAT AUG 29 2015

NO SIGNIFICANT AVIATION FORECAST CONCERNS OVERNIGHT. LIGHT TO
MODERATE SOUTHEASTERLY SURFACE WINDS WILL GRADUALLY VEER TO MORE
SOUTHWESTERLY THROUGH MID MORNING WITH A FEW PASSING HIGH LEVEL
CIRRUS CLOUDS OVERNIGHT. WINDS SHOULD PICK UP A BIT INTO THE 15-25
KT RANGE FROM THE SOUTHWEST FOR SOME SITES BY 17Z. IN SHORT VFR
CONDITIONS EXPECTED ALL SITES NEXT 24 HOURS.

&&

.FIRE WEATHER...
ISSUED AT 405 AM MDT SUN AUG 30 2015

HOT AND RELATIVELY DRY CONDITIONS ARE EXPECTED TODAY OVER MUCH OF
THE DISTRICT...WITH BREEZY WINDS THIS MORNING CONTINUING THROUGH
THE AFTERNOON IN THE HIGH COUNTRY AND FOR CONVERSE/NIOBRARA
COUNTIES. WINDS LOOK TO DIMINISH ALONG AND EAST OF THE LARAMIE
RANGE AFTER NOON TODAY. THE RED FLAG WARNING REMAINS IN EFFECT
FOR FWZ 301 FOR THE COMBINATION OF DRY AND BREEZY CONDITIONS.
INCREASING MOISTURE LATER THIS MORNING AND AFTERNOON WILL GIVE
CHANCES FOR WETTING RAINS MAINLY OVER THE MOUNTAINS AND PLAINS OF
SOUTHEAST WYOMING. CHANCES FOR RAIN WILL CONTINUE OVER THE
MOUNTAINS AND SOUTHERN WYO PLAINS THRU TUESDAY.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...RED FLAG WARNING FROM 11 AM THIS MORNING TO 7 PM MDT THIS
     EVENING FOR WYZ301.

NE...NONE.
&&

$$

SHORT TERM...RJM
LONG TERM...JG
AVIATION...JG
FIRE WEATHER...RJM



000
FXUS63 KUNR 300952
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
352 AM MDT SUN AUG 30 2015

.SHORT TERM...TODAY THROUGH MONDAY NIGHT
ISSUED AT 349 AM MDT SUN AUG 30 2015

SW FLOW ALOFT WILL INCREASE TODAY AS AN UPPER TROUGH CROSSES INTO
THE PAC NW. BREEZY SWRLY LOW LEVEL FLOW ACROSS THE HIGH PLAINS WILL
KEEP WARM AND DRY AIR OVER THE AREA TODAY. SURFACE OBS ACROSS THE
NRN/NERN BLKHLS AND ADJACENT FOOTHILLS SHOWING STRONG DOWNSLOPING
KEEPING OVERNIGHT TEMPS IN THE LOW TO MID 80S ALONG THE I90
CORRIDOR. MAX TEMPS WILL REACH THE 90S TO LOWER 100S. BREEZY S/SW
WINDS OF 10 TO 20 MPH ARE EXPECTED ACROSS THE PLAINS...POSSIBLY
BREEZIER OVER SCNTRL SD. COLD FRONT WILL CROSS THE AREA LATE THIS
AFTN INTO TONIGHT...WITH THE COLDER AIR NOT REACHING THE CWA UNTIL
LATE TONIGHT. COULD SEE SOME ISOLATED STORMS DEVELOP AHEAD OF THE
FRONT...BUT DRY LOW LEVELS WILL GREATLY HINDER INSTABILITY/QPF.
MOSTLY SUNNY SKIES AND BREEZY NW WINDS EXPECTED BEHIND THE FRONTAL
BOUNDARY THROUGH MON MORNING...BUT WINDS WILL DECREASE THROUGH THE
AFTN. TEMPS MON WILL BE A GOOD 10-15 DEGREES COOLER WITH HIGHS
REACHING THE MID 70S TO MID 80S. LOW MON NIGHT WILL DROP INTO THE
MID 50S TO MID 60S.

.LONG TERM...TUESDAY THROUGH SATURDAY
ISSUED AT 349 AM MDT SUN AUG 30 2015

UPPER TROUGH OVER THE PACIFIC NORTHWEST WILL LEAD TO
RIDGING OVER CENTRAL AND EASTERN CONUS THROUGH MUCH OF NEXT WEEK.
THIS WILL CREATE WARMER THAN AVERAGE TEMPERATURES. WEAK IMPULSES IN
THE SOUTHWESTERLY UPPER FLOW COULD CREATE A FEW ISOLATED
THUNDERSTORMS ESPECIALLY WHEN COMBINED WITH POSSIBLE LOW-MID LEVEL
THETA-E ADVECTION. DUE TO THE LACK OF ANY DECENT SIGNALS AND THE
EXPECTED EXTREMELY ISOLATED NATURE OF ANY CONVECTION WILL CONTINUE
WITH THE DRY FORECAST THROUGH THURSDAY. THE UPPER TROUGH WILL SHIFT
EASTWARD TOWARD THE FORECAST AREA FROM FRIDAY THROUGH THE
WEEKEND...CREATING A BETTER CHANCE OF SHOWERS AND LEADING TO
NOTICEABLY COOLER TEMPERATURES ON SATURDAY AND SUNDAY.

&&

.AVIATION...FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING
ISSUED AT 349 AM MDT SUN AUG 30 2015

BREEZY SOUTHERLY WINDS WILL PREVAIL ACROSS THE AREA
TODAY. MAINLY VFR CONDITIONS ARE EXPECTED WITH ISOLD MVFR VSBYS
POSSIBLE IN SMOKE FROM WESTERN WILDFIRES. THERE IS A SLIGHT CHANCE
OF THUNDERSTORMS OVER NORTHEASTERN WYOMING AND FAR WESTERN SOUTH
DAKOTA FROM LATE THIS AFTERNOON THROUGH THIS EVENING.

&&

.FIRE WEATHER...
ISSUED AT 349 AM MDT SUN AUG 30 2015

WARM AND DRY CONDITIONS WILL PERSIST ACROSS NE WY. RELATIVE
HUMIDITY ACROSS PORTIONS OF THE NORTHEAST WYOMING PLAINS WILL DROP
TO 15 PERCENT OR BELOW THIS AFTERNOON. GUSTY SOUTHWEST WINDS WILL
CONTINUE TODAY WITH SW WINDS OF 20 TO 30 MPH WITH GUSTS TO AROUND
35 MPH. A COLD FRONT WILL CROSS THE AREA LATE THIS AFTERNOON OR
TONIGHT. THERE IS A SLIGHT CHANCE FOR THUNDERSTORMS AHEAD OF THE
FRONT...WITH DRY LIGHTNING POSSIBLE.

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
WY...RED FLAG WARNING UNTIL 8 PM MDT THIS EVENING FOR WYZ259-297-298.

&&

$$

SHORT TERM...13
LONG TERM...10
AVIATION...10
FIRE WEATHER...13




000
FXUS65 KRIW 300850
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
250 AM MDT SUN AUG 30 2015

.SHORT TERM...TODAY THROUGH TUESDAY NIGHT

A STRONG TROUGH OF LOW PRESSURE JUST OFF THE PACIFIC NORTHWEST COAST
HAS EJECTED A SHEARED UPPER LEVEL SHORTWAVE EASTWARD THAT APPEARS TO
BE LOCATED OVER NORTHERN IDAHO AND WESTERN MT. ACTIVE CONVECTION
CONTINUES OUT AHEAD OF THIS FEATURE ACROSS EASTERN IDAHO NEAR THE
WYOMING BORDER AND INTO YNP AT THE TIME OF THIS WRITING. IT WILL BE
AN EARLY SHOW FOR CONVECTION IN WESTERN WY TODAY WITH THESE STORMS
ABOUT TO SWEEP ACROSS FAR WEST WYOMING DURING THE REMAINDER OF THE
NIGHT. THEN THE MAIN TROUGH WILL APPROACH THE NORTHERN ROCKIES TODAY
FOR ANOTHER ROUND OF CONVECTION FIRING UP IN FAR WESTERN WY BY MID
DAY AHEAD OF THE MAIN TROUGH AND ASCT COLD FRONT. IN THE
MEANTIME...EAST OF THE DIVIDE...SOUTHWEST WINDS WILL INCREASE OVER
WHAT THEY WERE SATURDAY AS THEY DRAW IN SLIGHTLY HIGHER LOWER LEVEL
MOISTURE. INSTABILITY WILL BE IN PLACE OVER THE ENTIRE CWA BUT ONLY
SCANT MOISTURE TO WORK WITH TO PRODUCE THUNDERSTORMS EAST OF THE
DIVIDE...AT LEAST INITIALLY IN THE EARLY TO MID AFTERNOON. THERE
WILL BE A SEPARATE FINGER OF WEAK HIGH AND MID LEVEL MONSOON
MOISTURE THAT WILL STREAM IN ACROSS RKS AND CPR. HOWEVER THE BEST
INSTABILITY WILL BE IN PLACE ACROSS NORTHERN WY WHERE THE BEST CAPES
WILL BE. IT APPEARS THE BEST CHANCE OF ANY DRY LIGHTNING WILL OCCUR
ON THE PERIPHERY OF ANY HIGH BASED THUNDERSTORMS ALONG THE
AFOREMENTIONED WEAK MONSOON MOISTURE PLUME AS WELL AS ACROSS
NORTHERN WY EAST OF THE DIVIDE WHERE RELATIVELY HIGH BASED STORMS
WILL CORRELATE WITH THE BEST CAPES. DRY THUNDERSTORMS WILL MORPH
INTO MORE WET STORMS AS THE FRONT DRAWS NEAR. THE TROUGHPA WILL
SWEEP ACROSS THE CWA TONIGHT. THEN ON MONDAY...ANOTHER SURGE OF WEAK
MID/UPPER LEVEL MOISTURE WILL OVERLAP SOME LINGERING INSTABILITY
OVER EXTREME SOUTHERN WY WHERE SOME ISOLD T STORMS ARE EXPECTED.
THEN BY TUESDAY...ANOTHER CLOSED LOW WILL ESTABLISH ITSELF ALONG THE
SOUTHERN BC COAST. THIS LOW WILL EJECT A WEAK VORT LOBE EAST
NORTHEAST ACROSS THE NORTHERN ROCKIES THAT WILL RESULT IN ISOLD
CONVECTION...MAINLY OVER THE NW MTNS TUE AFTERNOON. TODAY WILL BE A
COUPLE OF DEGREES COOLER THAN SATURDAY AS CLOUDS AND SHOWER ACTIVITY
DECREASE THE SOLAR INSULATION. AFTERWARD...TEMPS WILL COOL A FEW
DEGREES MONDAY BEFORE WARMING BACK UP TUESDAY.

.LONG TERM...WEDNESDAY THROUGH SUNDAY

HIGH LATITUDE ENERGY CURRENTLY OVER AK AND THE BERING SEA AREA WILL
DIVE SWD INTO OUR PACNW TROUGH AS UPSTREAM ENERGY...TYPHOON
REMNANTS...PUMPS UP THE UPSTREAM RIDGE OVER THE ERN PACIFIC. THE
END RESULT IS A DEEPENING COLD EARLY SEPTEMBER TROUGH OVER THE
PACNW AND INTERMOUNTAIN WEST THE SECOND HALF OF NEXT WEEK THAT
GRADUALLY TRANSLATES EWD AS THE FLOW DEAMPLIFYS TOWARDS THE END OF
THE PERIOD AND POSSIBLE SPLIT DEVELOPS OVER THE WEST EARLY NEXT
WEEK. THE MIDWEEK PERIOD WILL GENERALLY BE DRY AND QUITE WARM WITH
BREEZY TO LOCALLY WINDY PERIODS AND VERY LIMITED MAINLY MTN TSTMS
CHANCES AT BEST. BY FRIDAY...THE FIRST SIGNIFICANT SHORTWAVE OUT
AHEAD OF THE TROUGH IS ALREADY IMPACTING THE WEST AND NORTH AS A
COLD FRONT TRIES TO SAG SWD INTO THE NRN ZONES. THIS FRONTAL
BOUNDARY WILL BE A SIGNIFICANT PLAYER THROUGH THE WEEKEND WITH
CONSIDERABLY COOLER IF NOT COLDER WEATHER BEHIND IT AS THE MAIN
TROUGH OPENS UP AND PASSES ACROSS NRN WYO AND MONTANA OVER THE
LABOR DAY WEEKEND. A GOOD CHANCE OF SHOWERS AND TSTMS SHOULD OCCUR
IN AT LEAST THE NWRN SECTIONS WITH THIS FIRST SHORTWAVE AND THEN
MORE OF THE WEST AND NORTH AS THE DYNAMICS INTERACT/OVERRUN THE
FRONTAL BOUNDARY OVER THE WEEKEND. DETAILS ARE STILL UNCERTAIN BUT
THE GFS AND ECMWF ARE IN PRETTY GOOD AGREEMENT WITH THE BIG
PICTURE. THE SOURCE REGION OF THIS TROUGH IS QUITE COLD AND MODEL
GUIDANCE IS DROPPING H7 TEMPS DOWN TO AROUND ZERO TO EVEN BELOW
WITH THE FIRST SHORTWAVE FRIDAY NIGHT AND THEN WITH THE MAIN
TROUGH SATURDAY NIGHT SO MOUNTAINS WOULD GET A DECENT SHOT OF SOME
SNOW WITH EACH OF THESE. IT IS LABOR DAY WEEKEND AFTER ALL.

&&

.AVIATION.../12Z ISSUANCE/

A COLD FRONT WILL CONTINUE TO PUSH EAST ACROSS THE INTERMOUNTAIN
WEST TODAY WITH SFC SW FLOW INCREASING ACROSS WEST AND CENTRAL
WYOMING AHEAD OF THE FRONT...ALONG WITH AREAS OF LLWS.  SFC SW WINDS
AT 20-30KTS WILL PREVAIL ACROSS THE AREA LATE THIS MORNING INTO
THIS AFTERNOON. THE MAIN AREA ISOLD-SCT -TSRA WILL DEVELOP VCNTY
AND SOUTH OF A KEVW-KLND-KCPR LINE AROUND 18Z TODAY WITH THIS
AREA SLOWLY PROPAGATING SOUTH AND EAST THROUGH THE AFTERNOON AND
EARLY EVENING. THE COLD FRONT WILL BRING DRIER AIR AND GUSTY WEST
WIND INTO NW WYOMING MID TO LATE THIS AFTERNOON...PUSHING ACROSS
NORTH AND CENTRAL WYOMING THIS EVENING. CLEAR SKIES AND
DIMINISHING WIND WILL PREVAIL ACROSS THE AREA BEHIND THE FRONT
EARLY MONDAY MORNING.

&&

.FIRE WEATHER...

RED FLAG WARNING THROUGH SUNDAY FOR PORTIONS OF
CENTRAL WYOMING...

ON SUNDAY...OVERALL IT WILL BE WINDIER THAN IT WAS SATURDAY BUT WITH
SLIGHTLY HIGHER RELATIVE HUMIDITY. AS THE COLD FRONT ASSOCIATED WITH
THE TROUGH DIGGING TO THE WEST ADVANCES...IT WILL LIKELY SETTLE INTO
WESTERN...NORTHERN AND SOUTHERN WYOMING FAIRLY EARLY IN THE
DAY...WHICH WOULD END THE FIRE WEATHER THREAT IN THOSE LOCATIONS
ALONG WITH INCREASING CLOUDS AS WELL AS A SLIGHT CHANCE FOR A
WETTING RAIN. STRONG SOUTHWEST FLOW BUT STILL LOW HUMIDITY ACROSS
FREMONT...JOHNSON AND NATRONA COUNTIES WILL OCCUR SO THESE AREAS
WILL CONTINUE TO BE UNDER THE RED FLAG WARNING FOR TODAY. IN
ADDITION...A SWATH OF MID LEVEL MOISTURE AND CONTINUED INSTABILITY
WILL KICK OF A FEW MIXED WET AND DRY THUNDERSTORMS...SOME OF WHICH
COULD CONTRIBUTE TO NEW FIRE STARTS WITH THE MOST ACTIVITY EXPECTED
ACROSS NORTHERN AND WESTERN WYOMING...WITH A SECONDARY SWATH
EXPECTED OVER NATRONA AND EASTERN FREMONT COUNTIES LATE SUNDAY
AFTERNOON...THE CHANCE OF A WETTING RAIN OUT OF THESE STORMS IS NEXT
TO ZERO. THE BEST CHANCE OF ANY DRY LIGHTNING STARTS WILL LIKELY BE
ON THE PERIPHERY OF ANY THUNDERSTORMS THAT FORM ACROSS NORTHERN
WYOMING EAST OF THE DIVIDE THROUGH MID DAY WHERE THE BEST
INSTABILITY WILL BE...THEN FROM EASTERN SWEETWATER COUNTY TO CASPER
AND THE REST OF NATRONA COUNTY LATER IN THE AFTERNOON WHERE THE
COMBINATION OF DRIEST BOUNDARY LEVEL MOISTURE AND WIDEST TEMP/DEW
POINT SPREADS WILL LIE.

A REPEAT OF THESE CONDITIONS WILL BE POSSIBLE MID WEEK.



&&

.RIW WATCHES/WARNINGS/ADVISORIES...
RED FLAG WARNING UNTIL 9 PM MDT THIS EVENING FOR WYZ280-281-283-
285-289-300.

&&

$$

SHORT TERM...LIPSON
LONG TERM...PS
AVIATION...AEM
FIRE WEATHER...LIPSON



000
FXUS65 KRIW 300850
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
250 AM MDT SUN AUG 30 2015

.SHORT TERM...TODAY THROUGH TUESDAY NIGHT

A STRONG TROUGH OF LOW PRESSURE JUST OFF THE PACIFIC NORTHWEST COAST
HAS EJECTED A SHEARED UPPER LEVEL SHORTWAVE EASTWARD THAT APPEARS TO
BE LOCATED OVER NORTHERN IDAHO AND WESTERN MT. ACTIVE CONVECTION
CONTINUES OUT AHEAD OF THIS FEATURE ACROSS EASTERN IDAHO NEAR THE
WYOMING BORDER AND INTO YNP AT THE TIME OF THIS WRITING. IT WILL BE
AN EARLY SHOW FOR CONVECTION IN WESTERN WY TODAY WITH THESE STORMS
ABOUT TO SWEEP ACROSS FAR WEST WYOMING DURING THE REMAINDER OF THE
NIGHT. THEN THE MAIN TROUGH WILL APPROACH THE NORTHERN ROCKIES TODAY
FOR ANOTHER ROUND OF CONVECTION FIRING UP IN FAR WESTERN WY BY MID
DAY AHEAD OF THE MAIN TROUGH AND ASCT COLD FRONT. IN THE
MEANTIME...EAST OF THE DIVIDE...SOUTHWEST WINDS WILL INCREASE OVER
WHAT THEY WERE SATURDAY AS THEY DRAW IN SLIGHTLY HIGHER LOWER LEVEL
MOISTURE. INSTABILITY WILL BE IN PLACE OVER THE ENTIRE CWA BUT ONLY
SCANT MOISTURE TO WORK WITH TO PRODUCE THUNDERSTORMS EAST OF THE
DIVIDE...AT LEAST INITIALLY IN THE EARLY TO MID AFTERNOON. THERE
WILL BE A SEPARATE FINGER OF WEAK HIGH AND MID LEVEL MONSOON
MOISTURE THAT WILL STREAM IN ACROSS RKS AND CPR. HOWEVER THE BEST
INSTABILITY WILL BE IN PLACE ACROSS NORTHERN WY WHERE THE BEST CAPES
WILL BE. IT APPEARS THE BEST CHANCE OF ANY DRY LIGHTNING WILL OCCUR
ON THE PERIPHERY OF ANY HIGH BASED THUNDERSTORMS ALONG THE
AFOREMENTIONED WEAK MONSOON MOISTURE PLUME AS WELL AS ACROSS
NORTHERN WY EAST OF THE DIVIDE WHERE RELATIVELY HIGH BASED STORMS
WILL CORRELATE WITH THE BEST CAPES. DRY THUNDERSTORMS WILL MORPH
INTO MORE WET STORMS AS THE FRONT DRAWS NEAR. THE TROUGHPA WILL
SWEEP ACROSS THE CWA TONIGHT. THEN ON MONDAY...ANOTHER SURGE OF WEAK
MID/UPPER LEVEL MOISTURE WILL OVERLAP SOME LINGERING INSTABILITY
OVER EXTREME SOUTHERN WY WHERE SOME ISOLD T STORMS ARE EXPECTED.
THEN BY TUESDAY...ANOTHER CLOSED LOW WILL ESTABLISH ITSELF ALONG THE
SOUTHERN BC COAST. THIS LOW WILL EJECT A WEAK VORT LOBE EAST
NORTHEAST ACROSS THE NORTHERN ROCKIES THAT WILL RESULT IN ISOLD
CONVECTION...MAINLY OVER THE NW MTNS TUE AFTERNOON. TODAY WILL BE A
COUPLE OF DEGREES COOLER THAN SATURDAY AS CLOUDS AND SHOWER ACTIVITY
DECREASE THE SOLAR INSULATION. AFTERWARD...TEMPS WILL COOL A FEW
DEGREES MONDAY BEFORE WARMING BACK UP TUESDAY.

.LONG TERM...WEDNESDAY THROUGH SUNDAY

HIGH LATITUDE ENERGY CURRENTLY OVER AK AND THE BERING SEA AREA WILL
DIVE SWD INTO OUR PACNW TROUGH AS UPSTREAM ENERGY...TYPHOON
REMNANTS...PUMPS UP THE UPSTREAM RIDGE OVER THE ERN PACIFIC. THE
END RESULT IS A DEEPENING COLD EARLY SEPTEMBER TROUGH OVER THE
PACNW AND INTERMOUNTAIN WEST THE SECOND HALF OF NEXT WEEK THAT
GRADUALLY TRANSLATES EWD AS THE FLOW DEAMPLIFYS TOWARDS THE END OF
THE PERIOD AND POSSIBLE SPLIT DEVELOPS OVER THE WEST EARLY NEXT
WEEK. THE MIDWEEK PERIOD WILL GENERALLY BE DRY AND QUITE WARM WITH
BREEZY TO LOCALLY WINDY PERIODS AND VERY LIMITED MAINLY MTN TSTMS
CHANCES AT BEST. BY FRIDAY...THE FIRST SIGNIFICANT SHORTWAVE OUT
AHEAD OF THE TROUGH IS ALREADY IMPACTING THE WEST AND NORTH AS A
COLD FRONT TRIES TO SAG SWD INTO THE NRN ZONES. THIS FRONTAL
BOUNDARY WILL BE A SIGNIFICANT PLAYER THROUGH THE WEEKEND WITH
CONSIDERABLY COOLER IF NOT COLDER WEATHER BEHIND IT AS THE MAIN
TROUGH OPENS UP AND PASSES ACROSS NRN WYO AND MONTANA OVER THE
LABOR DAY WEEKEND. A GOOD CHANCE OF SHOWERS AND TSTMS SHOULD OCCUR
IN AT LEAST THE NWRN SECTIONS WITH THIS FIRST SHORTWAVE AND THEN
MORE OF THE WEST AND NORTH AS THE DYNAMICS INTERACT/OVERRUN THE
FRONTAL BOUNDARY OVER THE WEEKEND. DETAILS ARE STILL UNCERTAIN BUT
THE GFS AND ECMWF ARE IN PRETTY GOOD AGREEMENT WITH THE BIG
PICTURE. THE SOURCE REGION OF THIS TROUGH IS QUITE COLD AND MODEL
GUIDANCE IS DROPPING H7 TEMPS DOWN TO AROUND ZERO TO EVEN BELOW
WITH THE FIRST SHORTWAVE FRIDAY NIGHT AND THEN WITH THE MAIN
TROUGH SATURDAY NIGHT SO MOUNTAINS WOULD GET A DECENT SHOT OF SOME
SNOW WITH EACH OF THESE. IT IS LABOR DAY WEEKEND AFTER ALL.

&&

.AVIATION.../12Z ISSUANCE/

A COLD FRONT WILL CONTINUE TO PUSH EAST ACROSS THE INTERMOUNTAIN
WEST TODAY WITH SFC SW FLOW INCREASING ACROSS WEST AND CENTRAL
WYOMING AHEAD OF THE FRONT...ALONG WITH AREAS OF LLWS.  SFC SW WINDS
AT 20-30KTS WILL PREVAIL ACROSS THE AREA LATE THIS MORNING INTO
THIS AFTERNOON. THE MAIN AREA ISOLD-SCT -TSRA WILL DEVELOP VCNTY
AND SOUTH OF A KEVW-KLND-KCPR LINE AROUND 18Z TODAY WITH THIS
AREA SLOWLY PROPAGATING SOUTH AND EAST THROUGH THE AFTERNOON AND
EARLY EVENING. THE COLD FRONT WILL BRING DRIER AIR AND GUSTY WEST
WIND INTO NW WYOMING MID TO LATE THIS AFTERNOON...PUSHING ACROSS
NORTH AND CENTRAL WYOMING THIS EVENING. CLEAR SKIES AND
DIMINISHING WIND WILL PREVAIL ACROSS THE AREA BEHIND THE FRONT
EARLY MONDAY MORNING.

&&

.FIRE WEATHER...

RED FLAG WARNING THROUGH SUNDAY FOR PORTIONS OF
CENTRAL WYOMING...

ON SUNDAY...OVERALL IT WILL BE WINDIER THAN IT WAS SATURDAY BUT WITH
SLIGHTLY HIGHER RELATIVE HUMIDITY. AS THE COLD FRONT ASSOCIATED WITH
THE TROUGH DIGGING TO THE WEST ADVANCES...IT WILL LIKELY SETTLE INTO
WESTERN...NORTHERN AND SOUTHERN WYOMING FAIRLY EARLY IN THE
DAY...WHICH WOULD END THE FIRE WEATHER THREAT IN THOSE LOCATIONS
ALONG WITH INCREASING CLOUDS AS WELL AS A SLIGHT CHANCE FOR A
WETTING RAIN. STRONG SOUTHWEST FLOW BUT STILL LOW HUMIDITY ACROSS
FREMONT...JOHNSON AND NATRONA COUNTIES WILL OCCUR SO THESE AREAS
WILL CONTINUE TO BE UNDER THE RED FLAG WARNING FOR TODAY. IN
ADDITION...A SWATH OF MID LEVEL MOISTURE AND CONTINUED INSTABILITY
WILL KICK OF A FEW MIXED WET AND DRY THUNDERSTORMS...SOME OF WHICH
COULD CONTRIBUTE TO NEW FIRE STARTS WITH THE MOST ACTIVITY EXPECTED
ACROSS NORTHERN AND WESTERN WYOMING...WITH A SECONDARY SWATH
EXPECTED OVER NATRONA AND EASTERN FREMONT COUNTIES LATE SUNDAY
AFTERNOON...THE CHANCE OF A WETTING RAIN OUT OF THESE STORMS IS NEXT
TO ZERO. THE BEST CHANCE OF ANY DRY LIGHTNING STARTS WILL LIKELY BE
ON THE PERIPHERY OF ANY THUNDERSTORMS THAT FORM ACROSS NORTHERN
WYOMING EAST OF THE DIVIDE THROUGH MID DAY WHERE THE BEST
INSTABILITY WILL BE...THEN FROM EASTERN SWEETWATER COUNTY TO CASPER
AND THE REST OF NATRONA COUNTY LATER IN THE AFTERNOON WHERE THE
COMBINATION OF DRIEST BOUNDARY LEVEL MOISTURE AND WIDEST TEMP/DEW
POINT SPREADS WILL LIE.

A REPEAT OF THESE CONDITIONS WILL BE POSSIBLE MID WEEK.



&&

.RIW WATCHES/WARNINGS/ADVISORIES...
RED FLAG WARNING UNTIL 9 PM MDT THIS EVENING FOR WYZ280-281-283-
285-289-300.

&&

$$

SHORT TERM...LIPSON
LONG TERM...PS
AVIATION...AEM
FIRE WEATHER...LIPSON



000
FXUS65 KRIW 300850
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
250 AM MDT SUN AUG 30 2015

.SHORT TERM...TODAY THROUGH TUESDAY NIGHT

A STRONG TROUGH OF LOW PRESSURE JUST OFF THE PACIFIC NORTHWEST COAST
HAS EJECTED A SHEARED UPPER LEVEL SHORTWAVE EASTWARD THAT APPEARS TO
BE LOCATED OVER NORTHERN IDAHO AND WESTERN MT. ACTIVE CONVECTION
CONTINUES OUT AHEAD OF THIS FEATURE ACROSS EASTERN IDAHO NEAR THE
WYOMING BORDER AND INTO YNP AT THE TIME OF THIS WRITING. IT WILL BE
AN EARLY SHOW FOR CONVECTION IN WESTERN WY TODAY WITH THESE STORMS
ABOUT TO SWEEP ACROSS FAR WEST WYOMING DURING THE REMAINDER OF THE
NIGHT. THEN THE MAIN TROUGH WILL APPROACH THE NORTHERN ROCKIES TODAY
FOR ANOTHER ROUND OF CONVECTION FIRING UP IN FAR WESTERN WY BY MID
DAY AHEAD OF THE MAIN TROUGH AND ASCT COLD FRONT. IN THE
MEANTIME...EAST OF THE DIVIDE...SOUTHWEST WINDS WILL INCREASE OVER
WHAT THEY WERE SATURDAY AS THEY DRAW IN SLIGHTLY HIGHER LOWER LEVEL
MOISTURE. INSTABILITY WILL BE IN PLACE OVER THE ENTIRE CWA BUT ONLY
SCANT MOISTURE TO WORK WITH TO PRODUCE THUNDERSTORMS EAST OF THE
DIVIDE...AT LEAST INITIALLY IN THE EARLY TO MID AFTERNOON. THERE
WILL BE A SEPARATE FINGER OF WEAK HIGH AND MID LEVEL MONSOON
MOISTURE THAT WILL STREAM IN ACROSS RKS AND CPR. HOWEVER THE BEST
INSTABILITY WILL BE IN PLACE ACROSS NORTHERN WY WHERE THE BEST CAPES
WILL BE. IT APPEARS THE BEST CHANCE OF ANY DRY LIGHTNING WILL OCCUR
ON THE PERIPHERY OF ANY HIGH BASED THUNDERSTORMS ALONG THE
AFOREMENTIONED WEAK MONSOON MOISTURE PLUME AS WELL AS ACROSS
NORTHERN WY EAST OF THE DIVIDE WHERE RELATIVELY HIGH BASED STORMS
WILL CORRELATE WITH THE BEST CAPES. DRY THUNDERSTORMS WILL MORPH
INTO MORE WET STORMS AS THE FRONT DRAWS NEAR. THE TROUGHPA WILL
SWEEP ACROSS THE CWA TONIGHT. THEN ON MONDAY...ANOTHER SURGE OF WEAK
MID/UPPER LEVEL MOISTURE WILL OVERLAP SOME LINGERING INSTABILITY
OVER EXTREME SOUTHERN WY WHERE SOME ISOLD T STORMS ARE EXPECTED.
THEN BY TUESDAY...ANOTHER CLOSED LOW WILL ESTABLISH ITSELF ALONG THE
SOUTHERN BC COAST. THIS LOW WILL EJECT A WEAK VORT LOBE EAST
NORTHEAST ACROSS THE NORTHERN ROCKIES THAT WILL RESULT IN ISOLD
CONVECTION...MAINLY OVER THE NW MTNS TUE AFTERNOON. TODAY WILL BE A
COUPLE OF DEGREES COOLER THAN SATURDAY AS CLOUDS AND SHOWER ACTIVITY
DECREASE THE SOLAR INSULATION. AFTERWARD...TEMPS WILL COOL A FEW
DEGREES MONDAY BEFORE WARMING BACK UP TUESDAY.

.LONG TERM...WEDNESDAY THROUGH SUNDAY

HIGH LATITUDE ENERGY CURRENTLY OVER AK AND THE BERING SEA AREA WILL
DIVE SWD INTO OUR PACNW TROUGH AS UPSTREAM ENERGY...TYPHOON
REMNANTS...PUMPS UP THE UPSTREAM RIDGE OVER THE ERN PACIFIC. THE
END RESULT IS A DEEPENING COLD EARLY SEPTEMBER TROUGH OVER THE
PACNW AND INTERMOUNTAIN WEST THE SECOND HALF OF NEXT WEEK THAT
GRADUALLY TRANSLATES EWD AS THE FLOW DEAMPLIFYS TOWARDS THE END OF
THE PERIOD AND POSSIBLE SPLIT DEVELOPS OVER THE WEST EARLY NEXT
WEEK. THE MIDWEEK PERIOD WILL GENERALLY BE DRY AND QUITE WARM WITH
BREEZY TO LOCALLY WINDY PERIODS AND VERY LIMITED MAINLY MTN TSTMS
CHANCES AT BEST. BY FRIDAY...THE FIRST SIGNIFICANT SHORTWAVE OUT
AHEAD OF THE TROUGH IS ALREADY IMPACTING THE WEST AND NORTH AS A
COLD FRONT TRIES TO SAG SWD INTO THE NRN ZONES. THIS FRONTAL
BOUNDARY WILL BE A SIGNIFICANT PLAYER THROUGH THE WEEKEND WITH
CONSIDERABLY COOLER IF NOT COLDER WEATHER BEHIND IT AS THE MAIN
TROUGH OPENS UP AND PASSES ACROSS NRN WYO AND MONTANA OVER THE
LABOR DAY WEEKEND. A GOOD CHANCE OF SHOWERS AND TSTMS SHOULD OCCUR
IN AT LEAST THE NWRN SECTIONS WITH THIS FIRST SHORTWAVE AND THEN
MORE OF THE WEST AND NORTH AS THE DYNAMICS INTERACT/OVERRUN THE
FRONTAL BOUNDARY OVER THE WEEKEND. DETAILS ARE STILL UNCERTAIN BUT
THE GFS AND ECMWF ARE IN PRETTY GOOD AGREEMENT WITH THE BIG
PICTURE. THE SOURCE REGION OF THIS TROUGH IS QUITE COLD AND MODEL
GUIDANCE IS DROPPING H7 TEMPS DOWN TO AROUND ZERO TO EVEN BELOW
WITH THE FIRST SHORTWAVE FRIDAY NIGHT AND THEN WITH THE MAIN
TROUGH SATURDAY NIGHT SO MOUNTAINS WOULD GET A DECENT SHOT OF SOME
SNOW WITH EACH OF THESE. IT IS LABOR DAY WEEKEND AFTER ALL.

&&

.AVIATION.../12Z ISSUANCE/

A COLD FRONT WILL CONTINUE TO PUSH EAST ACROSS THE INTERMOUNTAIN
WEST TODAY WITH SFC SW FLOW INCREASING ACROSS WEST AND CENTRAL
WYOMING AHEAD OF THE FRONT...ALONG WITH AREAS OF LLWS.  SFC SW WINDS
AT 20-30KTS WILL PREVAIL ACROSS THE AREA LATE THIS MORNING INTO
THIS AFTERNOON. THE MAIN AREA ISOLD-SCT -TSRA WILL DEVELOP VCNTY
AND SOUTH OF A KEVW-KLND-KCPR LINE AROUND 18Z TODAY WITH THIS
AREA SLOWLY PROPAGATING SOUTH AND EAST THROUGH THE AFTERNOON AND
EARLY EVENING. THE COLD FRONT WILL BRING DRIER AIR AND GUSTY WEST
WIND INTO NW WYOMING MID TO LATE THIS AFTERNOON...PUSHING ACROSS
NORTH AND CENTRAL WYOMING THIS EVENING. CLEAR SKIES AND
DIMINISHING WIND WILL PREVAIL ACROSS THE AREA BEHIND THE FRONT
EARLY MONDAY MORNING.

&&

.FIRE WEATHER...

RED FLAG WARNING THROUGH SUNDAY FOR PORTIONS OF
CENTRAL WYOMING...

ON SUNDAY...OVERALL IT WILL BE WINDIER THAN IT WAS SATURDAY BUT WITH
SLIGHTLY HIGHER RELATIVE HUMIDITY. AS THE COLD FRONT ASSOCIATED WITH
THE TROUGH DIGGING TO THE WEST ADVANCES...IT WILL LIKELY SETTLE INTO
WESTERN...NORTHERN AND SOUTHERN WYOMING FAIRLY EARLY IN THE
DAY...WHICH WOULD END THE FIRE WEATHER THREAT IN THOSE LOCATIONS
ALONG WITH INCREASING CLOUDS AS WELL AS A SLIGHT CHANCE FOR A
WETTING RAIN. STRONG SOUTHWEST FLOW BUT STILL LOW HUMIDITY ACROSS
FREMONT...JOHNSON AND NATRONA COUNTIES WILL OCCUR SO THESE AREAS
WILL CONTINUE TO BE UNDER THE RED FLAG WARNING FOR TODAY. IN
ADDITION...A SWATH OF MID LEVEL MOISTURE AND CONTINUED INSTABILITY
WILL KICK OF A FEW MIXED WET AND DRY THUNDERSTORMS...SOME OF WHICH
COULD CONTRIBUTE TO NEW FIRE STARTS WITH THE MOST ACTIVITY EXPECTED
ACROSS NORTHERN AND WESTERN WYOMING...WITH A SECONDARY SWATH
EXPECTED OVER NATRONA AND EASTERN FREMONT COUNTIES LATE SUNDAY
AFTERNOON...THE CHANCE OF A WETTING RAIN OUT OF THESE STORMS IS NEXT
TO ZERO. THE BEST CHANCE OF ANY DRY LIGHTNING STARTS WILL LIKELY BE
ON THE PERIPHERY OF ANY THUNDERSTORMS THAT FORM ACROSS NORTHERN
WYOMING EAST OF THE DIVIDE THROUGH MID DAY WHERE THE BEST
INSTABILITY WILL BE...THEN FROM EASTERN SWEETWATER COUNTY TO CASPER
AND THE REST OF NATRONA COUNTY LATER IN THE AFTERNOON WHERE THE
COMBINATION OF DRIEST BOUNDARY LEVEL MOISTURE AND WIDEST TEMP/DEW
POINT SPREADS WILL LIE.

A REPEAT OF THESE CONDITIONS WILL BE POSSIBLE MID WEEK.



&&

.RIW WATCHES/WARNINGS/ADVISORIES...
RED FLAG WARNING UNTIL 9 PM MDT THIS EVENING FOR WYZ280-281-283-
285-289-300.

&&

$$

SHORT TERM...LIPSON
LONG TERM...PS
AVIATION...AEM
FIRE WEATHER...LIPSON



000
FXUS65 KRIW 300850
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
250 AM MDT SUN AUG 30 2015

.SHORT TERM...TODAY THROUGH TUESDAY NIGHT

A STRONG TROUGH OF LOW PRESSURE JUST OFF THE PACIFIC NORTHWEST COAST
HAS EJECTED A SHEARED UPPER LEVEL SHORTWAVE EASTWARD THAT APPEARS TO
BE LOCATED OVER NORTHERN IDAHO AND WESTERN MT. ACTIVE CONVECTION
CONTINUES OUT AHEAD OF THIS FEATURE ACROSS EASTERN IDAHO NEAR THE
WYOMING BORDER AND INTO YNP AT THE TIME OF THIS WRITING. IT WILL BE
AN EARLY SHOW FOR CONVECTION IN WESTERN WY TODAY WITH THESE STORMS
ABOUT TO SWEEP ACROSS FAR WEST WYOMING DURING THE REMAINDER OF THE
NIGHT. THEN THE MAIN TROUGH WILL APPROACH THE NORTHERN ROCKIES TODAY
FOR ANOTHER ROUND OF CONVECTION FIRING UP IN FAR WESTERN WY BY MID
DAY AHEAD OF THE MAIN TROUGH AND ASCT COLD FRONT. IN THE
MEANTIME...EAST OF THE DIVIDE...SOUTHWEST WINDS WILL INCREASE OVER
WHAT THEY WERE SATURDAY AS THEY DRAW IN SLIGHTLY HIGHER LOWER LEVEL
MOISTURE. INSTABILITY WILL BE IN PLACE OVER THE ENTIRE CWA BUT ONLY
SCANT MOISTURE TO WORK WITH TO PRODUCE THUNDERSTORMS EAST OF THE
DIVIDE...AT LEAST INITIALLY IN THE EARLY TO MID AFTERNOON. THERE
WILL BE A SEPARATE FINGER OF WEAK HIGH AND MID LEVEL MONSOON
MOISTURE THAT WILL STREAM IN ACROSS RKS AND CPR. HOWEVER THE BEST
INSTABILITY WILL BE IN PLACE ACROSS NORTHERN WY WHERE THE BEST CAPES
WILL BE. IT APPEARS THE BEST CHANCE OF ANY DRY LIGHTNING WILL OCCUR
ON THE PERIPHERY OF ANY HIGH BASED THUNDERSTORMS ALONG THE
AFOREMENTIONED WEAK MONSOON MOISTURE PLUME AS WELL AS ACROSS
NORTHERN WY EAST OF THE DIVIDE WHERE RELATIVELY HIGH BASED STORMS
WILL CORRELATE WITH THE BEST CAPES. DRY THUNDERSTORMS WILL MORPH
INTO MORE WET STORMS AS THE FRONT DRAWS NEAR. THE TROUGHPA WILL
SWEEP ACROSS THE CWA TONIGHT. THEN ON MONDAY...ANOTHER SURGE OF WEAK
MID/UPPER LEVEL MOISTURE WILL OVERLAP SOME LINGERING INSTABILITY
OVER EXTREME SOUTHERN WY WHERE SOME ISOLD T STORMS ARE EXPECTED.
THEN BY TUESDAY...ANOTHER CLOSED LOW WILL ESTABLISH ITSELF ALONG THE
SOUTHERN BC COAST. THIS LOW WILL EJECT A WEAK VORT LOBE EAST
NORTHEAST ACROSS THE NORTHERN ROCKIES THAT WILL RESULT IN ISOLD
CONVECTION...MAINLY OVER THE NW MTNS TUE AFTERNOON. TODAY WILL BE A
COUPLE OF DEGREES COOLER THAN SATURDAY AS CLOUDS AND SHOWER ACTIVITY
DECREASE THE SOLAR INSULATION. AFTERWARD...TEMPS WILL COOL A FEW
DEGREES MONDAY BEFORE WARMING BACK UP TUESDAY.

.LONG TERM...WEDNESDAY THROUGH SUNDAY

HIGH LATITUDE ENERGY CURRENTLY OVER AK AND THE BERING SEA AREA WILL
DIVE SWD INTO OUR PACNW TROUGH AS UPSTREAM ENERGY...TYPHOON
REMNANTS...PUMPS UP THE UPSTREAM RIDGE OVER THE ERN PACIFIC. THE
END RESULT IS A DEEPENING COLD EARLY SEPTEMBER TROUGH OVER THE
PACNW AND INTERMOUNTAIN WEST THE SECOND HALF OF NEXT WEEK THAT
GRADUALLY TRANSLATES EWD AS THE FLOW DEAMPLIFYS TOWARDS THE END OF
THE PERIOD AND POSSIBLE SPLIT DEVELOPS OVER THE WEST EARLY NEXT
WEEK. THE MIDWEEK PERIOD WILL GENERALLY BE DRY AND QUITE WARM WITH
BREEZY TO LOCALLY WINDY PERIODS AND VERY LIMITED MAINLY MTN TSTMS
CHANCES AT BEST. BY FRIDAY...THE FIRST SIGNIFICANT SHORTWAVE OUT
AHEAD OF THE TROUGH IS ALREADY IMPACTING THE WEST AND NORTH AS A
COLD FRONT TRIES TO SAG SWD INTO THE NRN ZONES. THIS FRONTAL
BOUNDARY WILL BE A SIGNIFICANT PLAYER THROUGH THE WEEKEND WITH
CONSIDERABLY COOLER IF NOT COLDER WEATHER BEHIND IT AS THE MAIN
TROUGH OPENS UP AND PASSES ACROSS NRN WYO AND MONTANA OVER THE
LABOR DAY WEEKEND. A GOOD CHANCE OF SHOWERS AND TSTMS SHOULD OCCUR
IN AT LEAST THE NWRN SECTIONS WITH THIS FIRST SHORTWAVE AND THEN
MORE OF THE WEST AND NORTH AS THE DYNAMICS INTERACT/OVERRUN THE
FRONTAL BOUNDARY OVER THE WEEKEND. DETAILS ARE STILL UNCERTAIN BUT
THE GFS AND ECMWF ARE IN PRETTY GOOD AGREEMENT WITH THE BIG
PICTURE. THE SOURCE REGION OF THIS TROUGH IS QUITE COLD AND MODEL
GUIDANCE IS DROPPING H7 TEMPS DOWN TO AROUND ZERO TO EVEN BELOW
WITH THE FIRST SHORTWAVE FRIDAY NIGHT AND THEN WITH THE MAIN
TROUGH SATURDAY NIGHT SO MOUNTAINS WOULD GET A DECENT SHOT OF SOME
SNOW WITH EACH OF THESE. IT IS LABOR DAY WEEKEND AFTER ALL.

&&

.AVIATION.../12Z ISSUANCE/

A COLD FRONT WILL CONTINUE TO PUSH EAST ACROSS THE INTERMOUNTAIN
WEST TODAY WITH SFC SW FLOW INCREASING ACROSS WEST AND CENTRAL
WYOMING AHEAD OF THE FRONT...ALONG WITH AREAS OF LLWS.  SFC SW WINDS
AT 20-30KTS WILL PREVAIL ACROSS THE AREA LATE THIS MORNING INTO
THIS AFTERNOON. THE MAIN AREA ISOLD-SCT -TSRA WILL DEVELOP VCNTY
AND SOUTH OF A KEVW-KLND-KCPR LINE AROUND 18Z TODAY WITH THIS
AREA SLOWLY PROPAGATING SOUTH AND EAST THROUGH THE AFTERNOON AND
EARLY EVENING. THE COLD FRONT WILL BRING DRIER AIR AND GUSTY WEST
WIND INTO NW WYOMING MID TO LATE THIS AFTERNOON...PUSHING ACROSS
NORTH AND CENTRAL WYOMING THIS EVENING. CLEAR SKIES AND
DIMINISHING WIND WILL PREVAIL ACROSS THE AREA BEHIND THE FRONT
EARLY MONDAY MORNING.

&&

.FIRE WEATHER...

RED FLAG WARNING THROUGH SUNDAY FOR PORTIONS OF
CENTRAL WYOMING...

ON SUNDAY...OVERALL IT WILL BE WINDIER THAN IT WAS SATURDAY BUT WITH
SLIGHTLY HIGHER RELATIVE HUMIDITY. AS THE COLD FRONT ASSOCIATED WITH
THE TROUGH DIGGING TO THE WEST ADVANCES...IT WILL LIKELY SETTLE INTO
WESTERN...NORTHERN AND SOUTHERN WYOMING FAIRLY EARLY IN THE
DAY...WHICH WOULD END THE FIRE WEATHER THREAT IN THOSE LOCATIONS
ALONG WITH INCREASING CLOUDS AS WELL AS A SLIGHT CHANCE FOR A
WETTING RAIN. STRONG SOUTHWEST FLOW BUT STILL LOW HUMIDITY ACROSS
FREMONT...JOHNSON AND NATRONA COUNTIES WILL OCCUR SO THESE AREAS
WILL CONTINUE TO BE UNDER THE RED FLAG WARNING FOR TODAY. IN
ADDITION...A SWATH OF MID LEVEL MOISTURE AND CONTINUED INSTABILITY
WILL KICK OF A FEW MIXED WET AND DRY THUNDERSTORMS...SOME OF WHICH
COULD CONTRIBUTE TO NEW FIRE STARTS WITH THE MOST ACTIVITY EXPECTED
ACROSS NORTHERN AND WESTERN WYOMING...WITH A SECONDARY SWATH
EXPECTED OVER NATRONA AND EASTERN FREMONT COUNTIES LATE SUNDAY
AFTERNOON...THE CHANCE OF A WETTING RAIN OUT OF THESE STORMS IS NEXT
TO ZERO. THE BEST CHANCE OF ANY DRY LIGHTNING STARTS WILL LIKELY BE
ON THE PERIPHERY OF ANY THUNDERSTORMS THAT FORM ACROSS NORTHERN
WYOMING EAST OF THE DIVIDE THROUGH MID DAY WHERE THE BEST
INSTABILITY WILL BE...THEN FROM EASTERN SWEETWATER COUNTY TO CASPER
AND THE REST OF NATRONA COUNTY LATER IN THE AFTERNOON WHERE THE
COMBINATION OF DRIEST BOUNDARY LEVEL MOISTURE AND WIDEST TEMP/DEW
POINT SPREADS WILL LIE.

A REPEAT OF THESE CONDITIONS WILL BE POSSIBLE MID WEEK.



&&

.RIW WATCHES/WARNINGS/ADVISORIES...
RED FLAG WARNING UNTIL 9 PM MDT THIS EVENING FOR WYZ280-281-283-
285-289-300.

&&

$$

SHORT TERM...LIPSON
LONG TERM...PS
AVIATION...AEM
FIRE WEATHER...LIPSON



000
FXUS65 KRIW 300558
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
1155 PM MDT SAT AUG 29 2015

.SHORT TERM...TONIGHT THROUGH SUNDAY NIGHT

HEIGHTS CONTINUE TO LOWER AS AN UPPER LEVEL RIDGE CONTINUES TO
SHIFT SOUTHEAST INTO THE CENTRAL PLAINS AND A DYNAMIC TROUGH
CONTINUES TO APPROACH FROM THE WEST. SOUTHWEST FLOW WILL CONTINUE
TO INCREASE INTO THE EVENING AND WILL REMAIN SPEEDY THROUGH
SUNDAY. AT THE SURFACE...A LEE TROUGH WILL DIG THROUGH THE DAY ON
SUNDAY FURTHER INCREASING THE GRADIENT IN PORTIONS OF CENTRAL AND
EASTERN WYOMING. AT THE SAME TIME...THE COLD FRONT ASSOCIATED
WITH THE PREVIOUSLY MENTIONED TROUGH WILL ADVANCE INTO WESTERN
WYOMING EARLY...DECREASING FIRE DANGER OVER WESTERN ZONES...THEN
IT WILL STALL FOR MUCH OF THE DAY ALLOWING DRY SOUTHWEST FLOW TO
RETURN TO AREAS EAST OF THE DIVIDE...SO THE RED FLAG WARNINGS WERE
EXTENDED IN JOHNSON FREMONT AND NATRONA COUNTIES INTO SUNDAY
EVENING. ALOFT...THE RIGHT ENTRANCE REGION OF A JET STREAK WILL
ENTER THE AREA INCREASING FORCING FOR ASCENT ACROSS MUCH OF THE
STATE...THE LIMITING FACTOR FOR THUNDERSTORMS OF COURSE WILL BE
MOISTURE. THERE ARE INDICATIONS OF SOME MID LEVEL MOISTURE NOSING
NORTH INTO EASTERN SWEETWATER...EASTERN FREMONT...NATRONA AND
SOUTHERN JOHNSON COUNTIES THAT COULD PROVIDE ENOUGH FUEL FOR
SOME VERY DRY AND HIGH BASED STORMS IN THE AFTERNOON. ACROSS
CENTRAL WYOMING...THERE WILL BE A LITTLE LESS MOISTURE AVAILABLE
FOR THUNDERSTORMS BUT THERE COULD BE A STRAY COME OFF OF THE
HIGHER TERRAIN...SO EXPANDED POPS TO ALL AREAS IN THE LATE
AFTERNOON. IN THE WESTERN MOUNTAINS...THERE WILL BE PLENTY OF
MOISTURE AND FORCING ALONG THE STALLED FRONT FOR SCATTERED
THUNDERSTORMS...THOUGH PRECIPITABLE WATER IS A BIT LIMITED SO
EXPECTING A MIX OF WET AND DRY STORMS THERE. RELATIVE HUMIDITY
WILL BE QUITE A BIT HIGHER SO THAT WILL LIMIT FIRE POTENTIAL. THE
COLD FRONT WILL FINALLY GAIN TRACTION AGAIN SUNDAY EVENING AND
WILL FINISH ITS PROGRESSION EASTWARD BY SUNRISE ON MONDAY.

.LONG TERM...MONDAY THROUGH SATURDAY

AGREEMENT AMONG MEDIUM-RANGE FORECAST MODELS IS VERY GOOD THROUGH
THE MIDDLE OF NEXT WEEK. SMALL DIFFERENCES FOR FRIDAY AND SATURDAY
HAVE BECOME BETTER ALIGNED WITH MOST RECENT MODELS RUNS WITH REGARDS
TO THE TRACK AND EVOLUTION OF A PACIFIC NORTHWEST TROUGH THAT WILL
MOVE THROUGH THE INTERMOUNTAIN WEST AND ROCKIES NEXT FRIDAY AND
SATURDAY.

DRIER WESTERLY FLOW WILL COVER THE FORECAST AREA MONDAY IN THE WAKE
OF THE DEPARTING SHORTWAVE TROUGH. SOME WEAK INSTABILITY AND
LINGERING MID-LEVEL MOISTURE NEAR THE COLORADO BORDER IN SWEETWATER
COUNTY DURING THE AFTERNOON AND EVENING. CONVECTION WOULD BE SHORT-
LIVED AND WEAK IF IT CAN MAKE MUCH PROGRESS OFF THE HIGHER TERRAIN
OF NORTHEAST UTAH. OTHERWISE...A DRY MONDAY WITH SEASONAL
TEMPERATURES AND LESS WIND THAT WHAT WILL BE SEEN THIS WEEKEND.
UPPER LEVEL FLOW BEGINS TO BACK TO THE SOUTHWEST ON TUESDAY IN
RESPONSE TO DEEPENING UPPER LEVEL LOW DIGGING INTO THE PACIFIC
NORTHWEST. THERE COULD BE ENOUGH MID-LEVEL MOISTURE TO INITIATE WEAK
MOUNTAIN CONVECTION TUESDAY THROUGH THURSDAY. THEREFORE...HAVE LEFT
LOW PRECIP CHANCES OVER MAINLY THE NORTHWEST MOUNTAINS. BELIEVE THAT
VERY LITTLE RAIN WOULD FALL WITH ANY CONVECTION THAT DEVELOPS AS DEW
POINTS WILL BE LESS THAN 40F AND PRECIPITABLE WATER VALUES LESS THAN
IMPRESSIVE. 700MB TEMPERATURES TUESDAY AND WEDNESDAY WILL AGAIN
APPROACH +15C WHICH WILL HAVE US STARING AT 90F SURFACE
TEMPERATURES. WOULD NOT BE SURPRISED TO SEE MAXIMUM TEMPERATURES
EXCEED 90F...ESPECIALLY ON WEDNESDAY AND MAYBE THURSDAY...DUE TO
INCREASING SOUTHWEST WIND AT THE SURFACE. THE MIDWEEK PATTERN...
BETWEEN TUESDAY AND THURSDAY...IS SHAPING UP TO BE ONE THAT COULD
HAVE CRITICAL FIRE WEATHER IMPLICATIONS. UNSEASONABLY WARM
TEMPERATURES...RELATIVE HUMIDITY IN THE TEENS...AND INCREASING
SOUTHWEST WIND AHEAD OF THE PACIFIC NORTHWEST TROUGH ALL LOOK TO BE
PRESENT ON THESE DAYS. IN FACT...DRIER SURFACE AIR WILL BE ADVECTED
INTO THE STATE FROM THE GREAT BASIN WITH AFTERNOON DEW POINTS
POSSIBLE FALLING TO LESS THAN 30F. THOSE WITH FIRE WEATHER INTERESTS
SHOULD CONTINUE TO MONITOR THE FORECAST FOR POSSIBLE HIGHLIGHTS.
APPROACH OF THE TROUGH WILL LEAD TO A BETTER OPPORTUNITY FOR
CONVECTION ACROSS THE NORTHWEST FRIDAY AFTERNOON AND EVENING. STILL
SOME DISCREPANCIES REGARDING HOW FAR SOUTH THE PACIFIC NORTHWEST
TROUGH WILL DIG AND HOW FAST IT WILL MOVE ACROSS THE FORECAST AREA.
BOTH ISSUES WILL HAVE AN IMPACT ON TEMPERATURES AND SENSIBLE WEATHER
HEADING INTO NEXT WEEKEND. COOLER AIR WILL SLIP SOUTH BEHIND A COLD
FRONT AND COOL THINGS DOWN FOR SATURDAY. FRIDAY TEMPERATURES WILL BE
MORE TRICKY AND DEPENDENT UPON THE TIMING OF THE COLD FRONTAL
PASSAGE. FORECAST FRIDAY TEMPERATURES EAST OF THE CONTINENTAL DIVIDE
COULD END UP BEING TOO COOL...BUT AT THIS RANGE HAVE NOT STRAYED
FROM KEEPING CONSISTENT REGIONAL FORECAST.

&&

.AVIATION.../06Z ISSUANCE/

A LINE OF THUNDERSTORMS WILL PUSH TO NEAR A VCNTY KJAC-KCOD LINE
THROUGH AROUND 07Z BEFORE DISSIPATING.  ERRATIC WIND GUSTS 30-40KTS
WILL BE THE MAIN HAZARD WITH THESE STORMS.  OTHERWISE ISOLD -SHRA/-
TSRA WILL CONTINUE VCNTY AND WEST OF THE DIVIDE OVERNIGHT.

A COLD FRONT WILL CONTINUE TO PUSH EAST ACROSS THE INTERMOUNTAIN
WEST ON SUNDAY WITH SFC SW FLOW INCREASING ACROSS WEST AND CENTRAL
WYOMING AHEAD OF THE FRONT...ALONG WITH AREAS OF LLWS.  SFC SW WINDS
AT 20-30KTS WILL PREVAIL ACROSS THE AREA LATE SUNDAY MORNING INTO
SUNDAY AFTERNOON.  THE MAIN AREA ISOLD-SCT -TSRA WILL DEVELOP VCNTY
AND SOUTH OF A KEVW-KLND-KCPR LINE AROUND 18Z SUNDAY WITH THIS AREA
SLOWLY PROPAGATING SOUTH AND EAST THROUGH THE AFTERNOON AND EARLY
EVENING.  THE COLD FRONT WILL BRING DRIER AIR AND GUSTY WEST WIND
INTO NW WYOMING MID TO LATE SUNDAY AFTERNOON...PUSHING ACROSS NORTH
AND CENTRAL WYOMING SUNDAY EVENING.  CLEAR SKIES AND DIMINISHING
WIND WILL PREVAIL ACROSS THE AREA BEHIND THE FRONT EARLY MONDAY
MORNING.

FIRE WEATHER...

.RED FLAG WARNING THROUGH SUNDAY FOR PORTIONS OF CENTRAL
WYOMING...

ON SUNDAY...OVERALL IT WILL BE WINDIER THAN IT WAS TODAY BUT WITH
SLIGHTLY HIGHER RELATIVE HUMIDITY. THE COLD FRONT ASSOCIATED WITH
THE TROUGH DIGGING TO THE WEST ADVANCES...IT WILL LIKELY SETTLE
INTO WESTERN...NORTHERN AND SOUTHERN WYOMING FAIRLY EARLY IN THE
DAY...WHICH WOULD END THE FIRE WEATHER THREAT IN THOSE LOCATIONS
ALONG WITH INCREASING CLOUDS AS WELL AS A SLIGHT CHANCE FOR A
WETTING RAIN. LATEST GUIDANCE CONTINUES TO SUGGEST THAT THE FRONT
WILL RETREAT BACK INTO MONTANA DURING THE LATE MORNING...CLEARING
THE WAY FOR MORE STRONG SOUTHWEST FLOW AND LOW HUMIDITY ACROSS
FREMONT...JOHNSON AND NATRONA COUNTIES. SO...THESE AREAS WILL
CONTINUE TO BE UNDER THE RED FLAG WARNING FOR SUNDAY. IN
ADDITION...A SWATH OF MID LEVEL MOISTURE AND CONTINUED INSTABILITY
WILL KICK OF A FEW MIXED WET AND DRY THUNDERSTORMS...SOME OF WHICH
COULD CONTRIBUTE TO NEW FIRE STARTS WITH THE MOST ACTIVITY
EXPECTED ACROSS NORTHERN AND WESTERN WYOMING...WITH A SECONDARY
SWATH EXPECTED OVER NATRONA AND EASTERN FREMONT COUNTIES LATE
SUNDAY AFTERNOON...THE CHANCE OF A WETTING RAIN OUT OF THESE
STORMS IS NEXT TO ZERO. THE BEST CHANCE OF ANY DRY LIGHTNING
STARTS WILL LIKELY BE ON THE PERIPHERY OF ANY THUNDERSTORMS OVER
NATRONA AND JOHNSON COUNTY WHERE THE COMBINATION OF DRIEST
BOUNDARY LEVEL MOISTURE...WIDEST TEMP/DEW POINT SPREADS AND
INSTABILITY WILL LIE ON SUNDAY AFTERNOON.

A REPEAT OF THESE CONDITIONS WILL BE POSSIBLE MID WEEK.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...
RED FLAG WARNING UNTIL 9 PM MDT THIS EVENING FOR WYZ275>277-279-
282-287-414>416.

RED FLAG WARNING UNTIL 9 PM MDT SUNDAY FOR WYZ280-281-283-285-
289-300.

&&

$$

SHORT TERM...ALLEN
LONG TERM...CNJ
AVIATION...AEM
FIRE WEATHER...ALLEN




000
FXUS65 KRIW 300558
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
1155 PM MDT SAT AUG 29 2015

.SHORT TERM...TONIGHT THROUGH SUNDAY NIGHT

HEIGHTS CONTINUE TO LOWER AS AN UPPER LEVEL RIDGE CONTINUES TO
SHIFT SOUTHEAST INTO THE CENTRAL PLAINS AND A DYNAMIC TROUGH
CONTINUES TO APPROACH FROM THE WEST. SOUTHWEST FLOW WILL CONTINUE
TO INCREASE INTO THE EVENING AND WILL REMAIN SPEEDY THROUGH
SUNDAY. AT THE SURFACE...A LEE TROUGH WILL DIG THROUGH THE DAY ON
SUNDAY FURTHER INCREASING THE GRADIENT IN PORTIONS OF CENTRAL AND
EASTERN WYOMING. AT THE SAME TIME...THE COLD FRONT ASSOCIATED
WITH THE PREVIOUSLY MENTIONED TROUGH WILL ADVANCE INTO WESTERN
WYOMING EARLY...DECREASING FIRE DANGER OVER WESTERN ZONES...THEN
IT WILL STALL FOR MUCH OF THE DAY ALLOWING DRY SOUTHWEST FLOW TO
RETURN TO AREAS EAST OF THE DIVIDE...SO THE RED FLAG WARNINGS WERE
EXTENDED IN JOHNSON FREMONT AND NATRONA COUNTIES INTO SUNDAY
EVENING. ALOFT...THE RIGHT ENTRANCE REGION OF A JET STREAK WILL
ENTER THE AREA INCREASING FORCING FOR ASCENT ACROSS MUCH OF THE
STATE...THE LIMITING FACTOR FOR THUNDERSTORMS OF COURSE WILL BE
MOISTURE. THERE ARE INDICATIONS OF SOME MID LEVEL MOISTURE NOSING
NORTH INTO EASTERN SWEETWATER...EASTERN FREMONT...NATRONA AND
SOUTHERN JOHNSON COUNTIES THAT COULD PROVIDE ENOUGH FUEL FOR
SOME VERY DRY AND HIGH BASED STORMS IN THE AFTERNOON. ACROSS
CENTRAL WYOMING...THERE WILL BE A LITTLE LESS MOISTURE AVAILABLE
FOR THUNDERSTORMS BUT THERE COULD BE A STRAY COME OFF OF THE
HIGHER TERRAIN...SO EXPANDED POPS TO ALL AREAS IN THE LATE
AFTERNOON. IN THE WESTERN MOUNTAINS...THERE WILL BE PLENTY OF
MOISTURE AND FORCING ALONG THE STALLED FRONT FOR SCATTERED
THUNDERSTORMS...THOUGH PRECIPITABLE WATER IS A BIT LIMITED SO
EXPECTING A MIX OF WET AND DRY STORMS THERE. RELATIVE HUMIDITY
WILL BE QUITE A BIT HIGHER SO THAT WILL LIMIT FIRE POTENTIAL. THE
COLD FRONT WILL FINALLY GAIN TRACTION AGAIN SUNDAY EVENING AND
WILL FINISH ITS PROGRESSION EASTWARD BY SUNRISE ON MONDAY.

.LONG TERM...MONDAY THROUGH SATURDAY

AGREEMENT AMONG MEDIUM-RANGE FORECAST MODELS IS VERY GOOD THROUGH
THE MIDDLE OF NEXT WEEK. SMALL DIFFERENCES FOR FRIDAY AND SATURDAY
HAVE BECOME BETTER ALIGNED WITH MOST RECENT MODELS RUNS WITH REGARDS
TO THE TRACK AND EVOLUTION OF A PACIFIC NORTHWEST TROUGH THAT WILL
MOVE THROUGH THE INTERMOUNTAIN WEST AND ROCKIES NEXT FRIDAY AND
SATURDAY.

DRIER WESTERLY FLOW WILL COVER THE FORECAST AREA MONDAY IN THE WAKE
OF THE DEPARTING SHORTWAVE TROUGH. SOME WEAK INSTABILITY AND
LINGERING MID-LEVEL MOISTURE NEAR THE COLORADO BORDER IN SWEETWATER
COUNTY DURING THE AFTERNOON AND EVENING. CONVECTION WOULD BE SHORT-
LIVED AND WEAK IF IT CAN MAKE MUCH PROGRESS OFF THE HIGHER TERRAIN
OF NORTHEAST UTAH. OTHERWISE...A DRY MONDAY WITH SEASONAL
TEMPERATURES AND LESS WIND THAT WHAT WILL BE SEEN THIS WEEKEND.
UPPER LEVEL FLOW BEGINS TO BACK TO THE SOUTHWEST ON TUESDAY IN
RESPONSE TO DEEPENING UPPER LEVEL LOW DIGGING INTO THE PACIFIC
NORTHWEST. THERE COULD BE ENOUGH MID-LEVEL MOISTURE TO INITIATE WEAK
MOUNTAIN CONVECTION TUESDAY THROUGH THURSDAY. THEREFORE...HAVE LEFT
LOW PRECIP CHANCES OVER MAINLY THE NORTHWEST MOUNTAINS. BELIEVE THAT
VERY LITTLE RAIN WOULD FALL WITH ANY CONVECTION THAT DEVELOPS AS DEW
POINTS WILL BE LESS THAN 40F AND PRECIPITABLE WATER VALUES LESS THAN
IMPRESSIVE. 700MB TEMPERATURES TUESDAY AND WEDNESDAY WILL AGAIN
APPROACH +15C WHICH WILL HAVE US STARING AT 90F SURFACE
TEMPERATURES. WOULD NOT BE SURPRISED TO SEE MAXIMUM TEMPERATURES
EXCEED 90F...ESPECIALLY ON WEDNESDAY AND MAYBE THURSDAY...DUE TO
INCREASING SOUTHWEST WIND AT THE SURFACE. THE MIDWEEK PATTERN...
BETWEEN TUESDAY AND THURSDAY...IS SHAPING UP TO BE ONE THAT COULD
HAVE CRITICAL FIRE WEATHER IMPLICATIONS. UNSEASONABLY WARM
TEMPERATURES...RELATIVE HUMIDITY IN THE TEENS...AND INCREASING
SOUTHWEST WIND AHEAD OF THE PACIFIC NORTHWEST TROUGH ALL LOOK TO BE
PRESENT ON THESE DAYS. IN FACT...DRIER SURFACE AIR WILL BE ADVECTED
INTO THE STATE FROM THE GREAT BASIN WITH AFTERNOON DEW POINTS
POSSIBLE FALLING TO LESS THAN 30F. THOSE WITH FIRE WEATHER INTERESTS
SHOULD CONTINUE TO MONITOR THE FORECAST FOR POSSIBLE HIGHLIGHTS.
APPROACH OF THE TROUGH WILL LEAD TO A BETTER OPPORTUNITY FOR
CONVECTION ACROSS THE NORTHWEST FRIDAY AFTERNOON AND EVENING. STILL
SOME DISCREPANCIES REGARDING HOW FAR SOUTH THE PACIFIC NORTHWEST
TROUGH WILL DIG AND HOW FAST IT WILL MOVE ACROSS THE FORECAST AREA.
BOTH ISSUES WILL HAVE AN IMPACT ON TEMPERATURES AND SENSIBLE WEATHER
HEADING INTO NEXT WEEKEND. COOLER AIR WILL SLIP SOUTH BEHIND A COLD
FRONT AND COOL THINGS DOWN FOR SATURDAY. FRIDAY TEMPERATURES WILL BE
MORE TRICKY AND DEPENDENT UPON THE TIMING OF THE COLD FRONTAL
PASSAGE. FORECAST FRIDAY TEMPERATURES EAST OF THE CONTINENTAL DIVIDE
COULD END UP BEING TOO COOL...BUT AT THIS RANGE HAVE NOT STRAYED
FROM KEEPING CONSISTENT REGIONAL FORECAST.

&&

.AVIATION.../06Z ISSUANCE/

A LINE OF THUNDERSTORMS WILL PUSH TO NEAR A VCNTY KJAC-KCOD LINE
THROUGH AROUND 07Z BEFORE DISSIPATING.  ERRATIC WIND GUSTS 30-40KTS
WILL BE THE MAIN HAZARD WITH THESE STORMS.  OTHERWISE ISOLD -SHRA/-
TSRA WILL CONTINUE VCNTY AND WEST OF THE DIVIDE OVERNIGHT.

A COLD FRONT WILL CONTINUE TO PUSH EAST ACROSS THE INTERMOUNTAIN
WEST ON SUNDAY WITH SFC SW FLOW INCREASING ACROSS WEST AND CENTRAL
WYOMING AHEAD OF THE FRONT...ALONG WITH AREAS OF LLWS.  SFC SW WINDS
AT 20-30KTS WILL PREVAIL ACROSS THE AREA LATE SUNDAY MORNING INTO
SUNDAY AFTERNOON.  THE MAIN AREA ISOLD-SCT -TSRA WILL DEVELOP VCNTY
AND SOUTH OF A KEVW-KLND-KCPR LINE AROUND 18Z SUNDAY WITH THIS AREA
SLOWLY PROPAGATING SOUTH AND EAST THROUGH THE AFTERNOON AND EARLY
EVENING.  THE COLD FRONT WILL BRING DRIER AIR AND GUSTY WEST WIND
INTO NW WYOMING MID TO LATE SUNDAY AFTERNOON...PUSHING ACROSS NORTH
AND CENTRAL WYOMING SUNDAY EVENING.  CLEAR SKIES AND DIMINISHING
WIND WILL PREVAIL ACROSS THE AREA BEHIND THE FRONT EARLY MONDAY
MORNING.

FIRE WEATHER...

.RED FLAG WARNING THROUGH SUNDAY FOR PORTIONS OF CENTRAL
WYOMING...

ON SUNDAY...OVERALL IT WILL BE WINDIER THAN IT WAS TODAY BUT WITH
SLIGHTLY HIGHER RELATIVE HUMIDITY. THE COLD FRONT ASSOCIATED WITH
THE TROUGH DIGGING TO THE WEST ADVANCES...IT WILL LIKELY SETTLE
INTO WESTERN...NORTHERN AND SOUTHERN WYOMING FAIRLY EARLY IN THE
DAY...WHICH WOULD END THE FIRE WEATHER THREAT IN THOSE LOCATIONS
ALONG WITH INCREASING CLOUDS AS WELL AS A SLIGHT CHANCE FOR A
WETTING RAIN. LATEST GUIDANCE CONTINUES TO SUGGEST THAT THE FRONT
WILL RETREAT BACK INTO MONTANA DURING THE LATE MORNING...CLEARING
THE WAY FOR MORE STRONG SOUTHWEST FLOW AND LOW HUMIDITY ACROSS
FREMONT...JOHNSON AND NATRONA COUNTIES. SO...THESE AREAS WILL
CONTINUE TO BE UNDER THE RED FLAG WARNING FOR SUNDAY. IN
ADDITION...A SWATH OF MID LEVEL MOISTURE AND CONTINUED INSTABILITY
WILL KICK OF A FEW MIXED WET AND DRY THUNDERSTORMS...SOME OF WHICH
COULD CONTRIBUTE TO NEW FIRE STARTS WITH THE MOST ACTIVITY
EXPECTED ACROSS NORTHERN AND WESTERN WYOMING...WITH A SECONDARY
SWATH EXPECTED OVER NATRONA AND EASTERN FREMONT COUNTIES LATE
SUNDAY AFTERNOON...THE CHANCE OF A WETTING RAIN OUT OF THESE
STORMS IS NEXT TO ZERO. THE BEST CHANCE OF ANY DRY LIGHTNING
STARTS WILL LIKELY BE ON THE PERIPHERY OF ANY THUNDERSTORMS OVER
NATRONA AND JOHNSON COUNTY WHERE THE COMBINATION OF DRIEST
BOUNDARY LEVEL MOISTURE...WIDEST TEMP/DEW POINT SPREADS AND
INSTABILITY WILL LIE ON SUNDAY AFTERNOON.

A REPEAT OF THESE CONDITIONS WILL BE POSSIBLE MID WEEK.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...
RED FLAG WARNING UNTIL 9 PM MDT THIS EVENING FOR WYZ275>277-279-
282-287-414>416.

RED FLAG WARNING UNTIL 9 PM MDT SUNDAY FOR WYZ280-281-283-285-
289-300.

&&

$$

SHORT TERM...ALLEN
LONG TERM...CNJ
AVIATION...AEM
FIRE WEATHER...ALLEN




000
FXUS65 KRIW 300558
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
1155 PM MDT SAT AUG 29 2015

.SHORT TERM...TONIGHT THROUGH SUNDAY NIGHT

HEIGHTS CONTINUE TO LOWER AS AN UPPER LEVEL RIDGE CONTINUES TO
SHIFT SOUTHEAST INTO THE CENTRAL PLAINS AND A DYNAMIC TROUGH
CONTINUES TO APPROACH FROM THE WEST. SOUTHWEST FLOW WILL CONTINUE
TO INCREASE INTO THE EVENING AND WILL REMAIN SPEEDY THROUGH
SUNDAY. AT THE SURFACE...A LEE TROUGH WILL DIG THROUGH THE DAY ON
SUNDAY FURTHER INCREASING THE GRADIENT IN PORTIONS OF CENTRAL AND
EASTERN WYOMING. AT THE SAME TIME...THE COLD FRONT ASSOCIATED
WITH THE PREVIOUSLY MENTIONED TROUGH WILL ADVANCE INTO WESTERN
WYOMING EARLY...DECREASING FIRE DANGER OVER WESTERN ZONES...THEN
IT WILL STALL FOR MUCH OF THE DAY ALLOWING DRY SOUTHWEST FLOW TO
RETURN TO AREAS EAST OF THE DIVIDE...SO THE RED FLAG WARNINGS WERE
EXTENDED IN JOHNSON FREMONT AND NATRONA COUNTIES INTO SUNDAY
EVENING. ALOFT...THE RIGHT ENTRANCE REGION OF A JET STREAK WILL
ENTER THE AREA INCREASING FORCING FOR ASCENT ACROSS MUCH OF THE
STATE...THE LIMITING FACTOR FOR THUNDERSTORMS OF COURSE WILL BE
MOISTURE. THERE ARE INDICATIONS OF SOME MID LEVEL MOISTURE NOSING
NORTH INTO EASTERN SWEETWATER...EASTERN FREMONT...NATRONA AND
SOUTHERN JOHNSON COUNTIES THAT COULD PROVIDE ENOUGH FUEL FOR
SOME VERY DRY AND HIGH BASED STORMS IN THE AFTERNOON. ACROSS
CENTRAL WYOMING...THERE WILL BE A LITTLE LESS MOISTURE AVAILABLE
FOR THUNDERSTORMS BUT THERE COULD BE A STRAY COME OFF OF THE
HIGHER TERRAIN...SO EXPANDED POPS TO ALL AREAS IN THE LATE
AFTERNOON. IN THE WESTERN MOUNTAINS...THERE WILL BE PLENTY OF
MOISTURE AND FORCING ALONG THE STALLED FRONT FOR SCATTERED
THUNDERSTORMS...THOUGH PRECIPITABLE WATER IS A BIT LIMITED SO
EXPECTING A MIX OF WET AND DRY STORMS THERE. RELATIVE HUMIDITY
WILL BE QUITE A BIT HIGHER SO THAT WILL LIMIT FIRE POTENTIAL. THE
COLD FRONT WILL FINALLY GAIN TRACTION AGAIN SUNDAY EVENING AND
WILL FINISH ITS PROGRESSION EASTWARD BY SUNRISE ON MONDAY.

.LONG TERM...MONDAY THROUGH SATURDAY

AGREEMENT AMONG MEDIUM-RANGE FORECAST MODELS IS VERY GOOD THROUGH
THE MIDDLE OF NEXT WEEK. SMALL DIFFERENCES FOR FRIDAY AND SATURDAY
HAVE BECOME BETTER ALIGNED WITH MOST RECENT MODELS RUNS WITH REGARDS
TO THE TRACK AND EVOLUTION OF A PACIFIC NORTHWEST TROUGH THAT WILL
MOVE THROUGH THE INTERMOUNTAIN WEST AND ROCKIES NEXT FRIDAY AND
SATURDAY.

DRIER WESTERLY FLOW WILL COVER THE FORECAST AREA MONDAY IN THE WAKE
OF THE DEPARTING SHORTWAVE TROUGH. SOME WEAK INSTABILITY AND
LINGERING MID-LEVEL MOISTURE NEAR THE COLORADO BORDER IN SWEETWATER
COUNTY DURING THE AFTERNOON AND EVENING. CONVECTION WOULD BE SHORT-
LIVED AND WEAK IF IT CAN MAKE MUCH PROGRESS OFF THE HIGHER TERRAIN
OF NORTHEAST UTAH. OTHERWISE...A DRY MONDAY WITH SEASONAL
TEMPERATURES AND LESS WIND THAT WHAT WILL BE SEEN THIS WEEKEND.
UPPER LEVEL FLOW BEGINS TO BACK TO THE SOUTHWEST ON TUESDAY IN
RESPONSE TO DEEPENING UPPER LEVEL LOW DIGGING INTO THE PACIFIC
NORTHWEST. THERE COULD BE ENOUGH MID-LEVEL MOISTURE TO INITIATE WEAK
MOUNTAIN CONVECTION TUESDAY THROUGH THURSDAY. THEREFORE...HAVE LEFT
LOW PRECIP CHANCES OVER MAINLY THE NORTHWEST MOUNTAINS. BELIEVE THAT
VERY LITTLE RAIN WOULD FALL WITH ANY CONVECTION THAT DEVELOPS AS DEW
POINTS WILL BE LESS THAN 40F AND PRECIPITABLE WATER VALUES LESS THAN
IMPRESSIVE. 700MB TEMPERATURES TUESDAY AND WEDNESDAY WILL AGAIN
APPROACH +15C WHICH WILL HAVE US STARING AT 90F SURFACE
TEMPERATURES. WOULD NOT BE SURPRISED TO SEE MAXIMUM TEMPERATURES
EXCEED 90F...ESPECIALLY ON WEDNESDAY AND MAYBE THURSDAY...DUE TO
INCREASING SOUTHWEST WIND AT THE SURFACE. THE MIDWEEK PATTERN...
BETWEEN TUESDAY AND THURSDAY...IS SHAPING UP TO BE ONE THAT COULD
HAVE CRITICAL FIRE WEATHER IMPLICATIONS. UNSEASONABLY WARM
TEMPERATURES...RELATIVE HUMIDITY IN THE TEENS...AND INCREASING
SOUTHWEST WIND AHEAD OF THE PACIFIC NORTHWEST TROUGH ALL LOOK TO BE
PRESENT ON THESE DAYS. IN FACT...DRIER SURFACE AIR WILL BE ADVECTED
INTO THE STATE FROM THE GREAT BASIN WITH AFTERNOON DEW POINTS
POSSIBLE FALLING TO LESS THAN 30F. THOSE WITH FIRE WEATHER INTERESTS
SHOULD CONTINUE TO MONITOR THE FORECAST FOR POSSIBLE HIGHLIGHTS.
APPROACH OF THE TROUGH WILL LEAD TO A BETTER OPPORTUNITY FOR
CONVECTION ACROSS THE NORTHWEST FRIDAY AFTERNOON AND EVENING. STILL
SOME DISCREPANCIES REGARDING HOW FAR SOUTH THE PACIFIC NORTHWEST
TROUGH WILL DIG AND HOW FAST IT WILL MOVE ACROSS THE FORECAST AREA.
BOTH ISSUES WILL HAVE AN IMPACT ON TEMPERATURES AND SENSIBLE WEATHER
HEADING INTO NEXT WEEKEND. COOLER AIR WILL SLIP SOUTH BEHIND A COLD
FRONT AND COOL THINGS DOWN FOR SATURDAY. FRIDAY TEMPERATURES WILL BE
MORE TRICKY AND DEPENDENT UPON THE TIMING OF THE COLD FRONTAL
PASSAGE. FORECAST FRIDAY TEMPERATURES EAST OF THE CONTINENTAL DIVIDE
COULD END UP BEING TOO COOL...BUT AT THIS RANGE HAVE NOT STRAYED
FROM KEEPING CONSISTENT REGIONAL FORECAST.

&&

.AVIATION.../06Z ISSUANCE/

A LINE OF THUNDERSTORMS WILL PUSH TO NEAR A VCNTY KJAC-KCOD LINE
THROUGH AROUND 07Z BEFORE DISSIPATING.  ERRATIC WIND GUSTS 30-40KTS
WILL BE THE MAIN HAZARD WITH THESE STORMS.  OTHERWISE ISOLD -SHRA/-
TSRA WILL CONTINUE VCNTY AND WEST OF THE DIVIDE OVERNIGHT.

A COLD FRONT WILL CONTINUE TO PUSH EAST ACROSS THE INTERMOUNTAIN
WEST ON SUNDAY WITH SFC SW FLOW INCREASING ACROSS WEST AND CENTRAL
WYOMING AHEAD OF THE FRONT...ALONG WITH AREAS OF LLWS.  SFC SW WINDS
AT 20-30KTS WILL PREVAIL ACROSS THE AREA LATE SUNDAY MORNING INTO
SUNDAY AFTERNOON.  THE MAIN AREA ISOLD-SCT -TSRA WILL DEVELOP VCNTY
AND SOUTH OF A KEVW-KLND-KCPR LINE AROUND 18Z SUNDAY WITH THIS AREA
SLOWLY PROPAGATING SOUTH AND EAST THROUGH THE AFTERNOON AND EARLY
EVENING.  THE COLD FRONT WILL BRING DRIER AIR AND GUSTY WEST WIND
INTO NW WYOMING MID TO LATE SUNDAY AFTERNOON...PUSHING ACROSS NORTH
AND CENTRAL WYOMING SUNDAY EVENING.  CLEAR SKIES AND DIMINISHING
WIND WILL PREVAIL ACROSS THE AREA BEHIND THE FRONT EARLY MONDAY
MORNING.

FIRE WEATHER...

.RED FLAG WARNING THROUGH SUNDAY FOR PORTIONS OF CENTRAL
WYOMING...

ON SUNDAY...OVERALL IT WILL BE WINDIER THAN IT WAS TODAY BUT WITH
SLIGHTLY HIGHER RELATIVE HUMIDITY. THE COLD FRONT ASSOCIATED WITH
THE TROUGH DIGGING TO THE WEST ADVANCES...IT WILL LIKELY SETTLE
INTO WESTERN...NORTHERN AND SOUTHERN WYOMING FAIRLY EARLY IN THE
DAY...WHICH WOULD END THE FIRE WEATHER THREAT IN THOSE LOCATIONS
ALONG WITH INCREASING CLOUDS AS WELL AS A SLIGHT CHANCE FOR A
WETTING RAIN. LATEST GUIDANCE CONTINUES TO SUGGEST THAT THE FRONT
WILL RETREAT BACK INTO MONTANA DURING THE LATE MORNING...CLEARING
THE WAY FOR MORE STRONG SOUTHWEST FLOW AND LOW HUMIDITY ACROSS
FREMONT...JOHNSON AND NATRONA COUNTIES. SO...THESE AREAS WILL
CONTINUE TO BE UNDER THE RED FLAG WARNING FOR SUNDAY. IN
ADDITION...A SWATH OF MID LEVEL MOISTURE AND CONTINUED INSTABILITY
WILL KICK OF A FEW MIXED WET AND DRY THUNDERSTORMS...SOME OF WHICH
COULD CONTRIBUTE TO NEW FIRE STARTS WITH THE MOST ACTIVITY
EXPECTED ACROSS NORTHERN AND WESTERN WYOMING...WITH A SECONDARY
SWATH EXPECTED OVER NATRONA AND EASTERN FREMONT COUNTIES LATE
SUNDAY AFTERNOON...THE CHANCE OF A WETTING RAIN OUT OF THESE
STORMS IS NEXT TO ZERO. THE BEST CHANCE OF ANY DRY LIGHTNING
STARTS WILL LIKELY BE ON THE PERIPHERY OF ANY THUNDERSTORMS OVER
NATRONA AND JOHNSON COUNTY WHERE THE COMBINATION OF DRIEST
BOUNDARY LEVEL MOISTURE...WIDEST TEMP/DEW POINT SPREADS AND
INSTABILITY WILL LIE ON SUNDAY AFTERNOON.

A REPEAT OF THESE CONDITIONS WILL BE POSSIBLE MID WEEK.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...
RED FLAG WARNING UNTIL 9 PM MDT THIS EVENING FOR WYZ275>277-279-
282-287-414>416.

RED FLAG WARNING UNTIL 9 PM MDT SUNDAY FOR WYZ280-281-283-285-
289-300.

&&

$$

SHORT TERM...ALLEN
LONG TERM...CNJ
AVIATION...AEM
FIRE WEATHER...ALLEN




000
FXUS65 KRIW 300558
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
1155 PM MDT SAT AUG 29 2015

.SHORT TERM...TONIGHT THROUGH SUNDAY NIGHT

HEIGHTS CONTINUE TO LOWER AS AN UPPER LEVEL RIDGE CONTINUES TO
SHIFT SOUTHEAST INTO THE CENTRAL PLAINS AND A DYNAMIC TROUGH
CONTINUES TO APPROACH FROM THE WEST. SOUTHWEST FLOW WILL CONTINUE
TO INCREASE INTO THE EVENING AND WILL REMAIN SPEEDY THROUGH
SUNDAY. AT THE SURFACE...A LEE TROUGH WILL DIG THROUGH THE DAY ON
SUNDAY FURTHER INCREASING THE GRADIENT IN PORTIONS OF CENTRAL AND
EASTERN WYOMING. AT THE SAME TIME...THE COLD FRONT ASSOCIATED
WITH THE PREVIOUSLY MENTIONED TROUGH WILL ADVANCE INTO WESTERN
WYOMING EARLY...DECREASING FIRE DANGER OVER WESTERN ZONES...THEN
IT WILL STALL FOR MUCH OF THE DAY ALLOWING DRY SOUTHWEST FLOW TO
RETURN TO AREAS EAST OF THE DIVIDE...SO THE RED FLAG WARNINGS WERE
EXTENDED IN JOHNSON FREMONT AND NATRONA COUNTIES INTO SUNDAY
EVENING. ALOFT...THE RIGHT ENTRANCE REGION OF A JET STREAK WILL
ENTER THE AREA INCREASING FORCING FOR ASCENT ACROSS MUCH OF THE
STATE...THE LIMITING FACTOR FOR THUNDERSTORMS OF COURSE WILL BE
MOISTURE. THERE ARE INDICATIONS OF SOME MID LEVEL MOISTURE NOSING
NORTH INTO EASTERN SWEETWATER...EASTERN FREMONT...NATRONA AND
SOUTHERN JOHNSON COUNTIES THAT COULD PROVIDE ENOUGH FUEL FOR
SOME VERY DRY AND HIGH BASED STORMS IN THE AFTERNOON. ACROSS
CENTRAL WYOMING...THERE WILL BE A LITTLE LESS MOISTURE AVAILABLE
FOR THUNDERSTORMS BUT THERE COULD BE A STRAY COME OFF OF THE
HIGHER TERRAIN...SO EXPANDED POPS TO ALL AREAS IN THE LATE
AFTERNOON. IN THE WESTERN MOUNTAINS...THERE WILL BE PLENTY OF
MOISTURE AND FORCING ALONG THE STALLED FRONT FOR SCATTERED
THUNDERSTORMS...THOUGH PRECIPITABLE WATER IS A BIT LIMITED SO
EXPECTING A MIX OF WET AND DRY STORMS THERE. RELATIVE HUMIDITY
WILL BE QUITE A BIT HIGHER SO THAT WILL LIMIT FIRE POTENTIAL. THE
COLD FRONT WILL FINALLY GAIN TRACTION AGAIN SUNDAY EVENING AND
WILL FINISH ITS PROGRESSION EASTWARD BY SUNRISE ON MONDAY.

.LONG TERM...MONDAY THROUGH SATURDAY

AGREEMENT AMONG MEDIUM-RANGE FORECAST MODELS IS VERY GOOD THROUGH
THE MIDDLE OF NEXT WEEK. SMALL DIFFERENCES FOR FRIDAY AND SATURDAY
HAVE BECOME BETTER ALIGNED WITH MOST RECENT MODELS RUNS WITH REGARDS
TO THE TRACK AND EVOLUTION OF A PACIFIC NORTHWEST TROUGH THAT WILL
MOVE THROUGH THE INTERMOUNTAIN WEST AND ROCKIES NEXT FRIDAY AND
SATURDAY.

DRIER WESTERLY FLOW WILL COVER THE FORECAST AREA MONDAY IN THE WAKE
OF THE DEPARTING SHORTWAVE TROUGH. SOME WEAK INSTABILITY AND
LINGERING MID-LEVEL MOISTURE NEAR THE COLORADO BORDER IN SWEETWATER
COUNTY DURING THE AFTERNOON AND EVENING. CONVECTION WOULD BE SHORT-
LIVED AND WEAK IF IT CAN MAKE MUCH PROGRESS OFF THE HIGHER TERRAIN
OF NORTHEAST UTAH. OTHERWISE...A DRY MONDAY WITH SEASONAL
TEMPERATURES AND LESS WIND THAT WHAT WILL BE SEEN THIS WEEKEND.
UPPER LEVEL FLOW BEGINS TO BACK TO THE SOUTHWEST ON TUESDAY IN
RESPONSE TO DEEPENING UPPER LEVEL LOW DIGGING INTO THE PACIFIC
NORTHWEST. THERE COULD BE ENOUGH MID-LEVEL MOISTURE TO INITIATE WEAK
MOUNTAIN CONVECTION TUESDAY THROUGH THURSDAY. THEREFORE...HAVE LEFT
LOW PRECIP CHANCES OVER MAINLY THE NORTHWEST MOUNTAINS. BELIEVE THAT
VERY LITTLE RAIN WOULD FALL WITH ANY CONVECTION THAT DEVELOPS AS DEW
POINTS WILL BE LESS THAN 40F AND PRECIPITABLE WATER VALUES LESS THAN
IMPRESSIVE. 700MB TEMPERATURES TUESDAY AND WEDNESDAY WILL AGAIN
APPROACH +15C WHICH WILL HAVE US STARING AT 90F SURFACE
TEMPERATURES. WOULD NOT BE SURPRISED TO SEE MAXIMUM TEMPERATURES
EXCEED 90F...ESPECIALLY ON WEDNESDAY AND MAYBE THURSDAY...DUE TO
INCREASING SOUTHWEST WIND AT THE SURFACE. THE MIDWEEK PATTERN...
BETWEEN TUESDAY AND THURSDAY...IS SHAPING UP TO BE ONE THAT COULD
HAVE CRITICAL FIRE WEATHER IMPLICATIONS. UNSEASONABLY WARM
TEMPERATURES...RELATIVE HUMIDITY IN THE TEENS...AND INCREASING
SOUTHWEST WIND AHEAD OF THE PACIFIC NORTHWEST TROUGH ALL LOOK TO BE
PRESENT ON THESE DAYS. IN FACT...DRIER SURFACE AIR WILL BE ADVECTED
INTO THE STATE FROM THE GREAT BASIN WITH AFTERNOON DEW POINTS
POSSIBLE FALLING TO LESS THAN 30F. THOSE WITH FIRE WEATHER INTERESTS
SHOULD CONTINUE TO MONITOR THE FORECAST FOR POSSIBLE HIGHLIGHTS.
APPROACH OF THE TROUGH WILL LEAD TO A BETTER OPPORTUNITY FOR
CONVECTION ACROSS THE NORTHWEST FRIDAY AFTERNOON AND EVENING. STILL
SOME DISCREPANCIES REGARDING HOW FAR SOUTH THE PACIFIC NORTHWEST
TROUGH WILL DIG AND HOW FAST IT WILL MOVE ACROSS THE FORECAST AREA.
BOTH ISSUES WILL HAVE AN IMPACT ON TEMPERATURES AND SENSIBLE WEATHER
HEADING INTO NEXT WEEKEND. COOLER AIR WILL SLIP SOUTH BEHIND A COLD
FRONT AND COOL THINGS DOWN FOR SATURDAY. FRIDAY TEMPERATURES WILL BE
MORE TRICKY AND DEPENDENT UPON THE TIMING OF THE COLD FRONTAL
PASSAGE. FORECAST FRIDAY TEMPERATURES EAST OF THE CONTINENTAL DIVIDE
COULD END UP BEING TOO COOL...BUT AT THIS RANGE HAVE NOT STRAYED
FROM KEEPING CONSISTENT REGIONAL FORECAST.

&&

.AVIATION.../06Z ISSUANCE/

A LINE OF THUNDERSTORMS WILL PUSH TO NEAR A VCNTY KJAC-KCOD LINE
THROUGH AROUND 07Z BEFORE DISSIPATING.  ERRATIC WIND GUSTS 30-40KTS
WILL BE THE MAIN HAZARD WITH THESE STORMS.  OTHERWISE ISOLD -SHRA/-
TSRA WILL CONTINUE VCNTY AND WEST OF THE DIVIDE OVERNIGHT.

A COLD FRONT WILL CONTINUE TO PUSH EAST ACROSS THE INTERMOUNTAIN
WEST ON SUNDAY WITH SFC SW FLOW INCREASING ACROSS WEST AND CENTRAL
WYOMING AHEAD OF THE FRONT...ALONG WITH AREAS OF LLWS.  SFC SW WINDS
AT 20-30KTS WILL PREVAIL ACROSS THE AREA LATE SUNDAY MORNING INTO
SUNDAY AFTERNOON.  THE MAIN AREA ISOLD-SCT -TSRA WILL DEVELOP VCNTY
AND SOUTH OF A KEVW-KLND-KCPR LINE AROUND 18Z SUNDAY WITH THIS AREA
SLOWLY PROPAGATING SOUTH AND EAST THROUGH THE AFTERNOON AND EARLY
EVENING.  THE COLD FRONT WILL BRING DRIER AIR AND GUSTY WEST WIND
INTO NW WYOMING MID TO LATE SUNDAY AFTERNOON...PUSHING ACROSS NORTH
AND CENTRAL WYOMING SUNDAY EVENING.  CLEAR SKIES AND DIMINISHING
WIND WILL PREVAIL ACROSS THE AREA BEHIND THE FRONT EARLY MONDAY
MORNING.

FIRE WEATHER...

.RED FLAG WARNING THROUGH SUNDAY FOR PORTIONS OF CENTRAL
WYOMING...

ON SUNDAY...OVERALL IT WILL BE WINDIER THAN IT WAS TODAY BUT WITH
SLIGHTLY HIGHER RELATIVE HUMIDITY. THE COLD FRONT ASSOCIATED WITH
THE TROUGH DIGGING TO THE WEST ADVANCES...IT WILL LIKELY SETTLE
INTO WESTERN...NORTHERN AND SOUTHERN WYOMING FAIRLY EARLY IN THE
DAY...WHICH WOULD END THE FIRE WEATHER THREAT IN THOSE LOCATIONS
ALONG WITH INCREASING CLOUDS AS WELL AS A SLIGHT CHANCE FOR A
WETTING RAIN. LATEST GUIDANCE CONTINUES TO SUGGEST THAT THE FRONT
WILL RETREAT BACK INTO MONTANA DURING THE LATE MORNING...CLEARING
THE WAY FOR MORE STRONG SOUTHWEST FLOW AND LOW HUMIDITY ACROSS
FREMONT...JOHNSON AND NATRONA COUNTIES. SO...THESE AREAS WILL
CONTINUE TO BE UNDER THE RED FLAG WARNING FOR SUNDAY. IN
ADDITION...A SWATH OF MID LEVEL MOISTURE AND CONTINUED INSTABILITY
WILL KICK OF A FEW MIXED WET AND DRY THUNDERSTORMS...SOME OF WHICH
COULD CONTRIBUTE TO NEW FIRE STARTS WITH THE MOST ACTIVITY
EXPECTED ACROSS NORTHERN AND WESTERN WYOMING...WITH A SECONDARY
SWATH EXPECTED OVER NATRONA AND EASTERN FREMONT COUNTIES LATE
SUNDAY AFTERNOON...THE CHANCE OF A WETTING RAIN OUT OF THESE
STORMS IS NEXT TO ZERO. THE BEST CHANCE OF ANY DRY LIGHTNING
STARTS WILL LIKELY BE ON THE PERIPHERY OF ANY THUNDERSTORMS OVER
NATRONA AND JOHNSON COUNTY WHERE THE COMBINATION OF DRIEST
BOUNDARY LEVEL MOISTURE...WIDEST TEMP/DEW POINT SPREADS AND
INSTABILITY WILL LIE ON SUNDAY AFTERNOON.

A REPEAT OF THESE CONDITIONS WILL BE POSSIBLE MID WEEK.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...
RED FLAG WARNING UNTIL 9 PM MDT THIS EVENING FOR WYZ275>277-279-
282-287-414>416.

RED FLAG WARNING UNTIL 9 PM MDT SUNDAY FOR WYZ280-281-283-285-
289-300.

&&

$$

SHORT TERM...ALLEN
LONG TERM...CNJ
AVIATION...AEM
FIRE WEATHER...ALLEN




000
FXUS65 KRIW 300558
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
1155 PM MDT SAT AUG 29 2015

.SHORT TERM...TONIGHT THROUGH SUNDAY NIGHT

HEIGHTS CONTINUE TO LOWER AS AN UPPER LEVEL RIDGE CONTINUES TO
SHIFT SOUTHEAST INTO THE CENTRAL PLAINS AND A DYNAMIC TROUGH
CONTINUES TO APPROACH FROM THE WEST. SOUTHWEST FLOW WILL CONTINUE
TO INCREASE INTO THE EVENING AND WILL REMAIN SPEEDY THROUGH
SUNDAY. AT THE SURFACE...A LEE TROUGH WILL DIG THROUGH THE DAY ON
SUNDAY FURTHER INCREASING THE GRADIENT IN PORTIONS OF CENTRAL AND
EASTERN WYOMING. AT THE SAME TIME...THE COLD FRONT ASSOCIATED
WITH THE PREVIOUSLY MENTIONED TROUGH WILL ADVANCE INTO WESTERN
WYOMING EARLY...DECREASING FIRE DANGER OVER WESTERN ZONES...THEN
IT WILL STALL FOR MUCH OF THE DAY ALLOWING DRY SOUTHWEST FLOW TO
RETURN TO AREAS EAST OF THE DIVIDE...SO THE RED FLAG WARNINGS WERE
EXTENDED IN JOHNSON FREMONT AND NATRONA COUNTIES INTO SUNDAY
EVENING. ALOFT...THE RIGHT ENTRANCE REGION OF A JET STREAK WILL
ENTER THE AREA INCREASING FORCING FOR ASCENT ACROSS MUCH OF THE
STATE...THE LIMITING FACTOR FOR THUNDERSTORMS OF COURSE WILL BE
MOISTURE. THERE ARE INDICATIONS OF SOME MID LEVEL MOISTURE NOSING
NORTH INTO EASTERN SWEETWATER...EASTERN FREMONT...NATRONA AND
SOUTHERN JOHNSON COUNTIES THAT COULD PROVIDE ENOUGH FUEL FOR
SOME VERY DRY AND HIGH BASED STORMS IN THE AFTERNOON. ACROSS
CENTRAL WYOMING...THERE WILL BE A LITTLE LESS MOISTURE AVAILABLE
FOR THUNDERSTORMS BUT THERE COULD BE A STRAY COME OFF OF THE
HIGHER TERRAIN...SO EXPANDED POPS TO ALL AREAS IN THE LATE
AFTERNOON. IN THE WESTERN MOUNTAINS...THERE WILL BE PLENTY OF
MOISTURE AND FORCING ALONG THE STALLED FRONT FOR SCATTERED
THUNDERSTORMS...THOUGH PRECIPITABLE WATER IS A BIT LIMITED SO
EXPECTING A MIX OF WET AND DRY STORMS THERE. RELATIVE HUMIDITY
WILL BE QUITE A BIT HIGHER SO THAT WILL LIMIT FIRE POTENTIAL. THE
COLD FRONT WILL FINALLY GAIN TRACTION AGAIN SUNDAY EVENING AND
WILL FINISH ITS PROGRESSION EASTWARD BY SUNRISE ON MONDAY.

.LONG TERM...MONDAY THROUGH SATURDAY

AGREEMENT AMONG MEDIUM-RANGE FORECAST MODELS IS VERY GOOD THROUGH
THE MIDDLE OF NEXT WEEK. SMALL DIFFERENCES FOR FRIDAY AND SATURDAY
HAVE BECOME BETTER ALIGNED WITH MOST RECENT MODELS RUNS WITH REGARDS
TO THE TRACK AND EVOLUTION OF A PACIFIC NORTHWEST TROUGH THAT WILL
MOVE THROUGH THE INTERMOUNTAIN WEST AND ROCKIES NEXT FRIDAY AND
SATURDAY.

DRIER WESTERLY FLOW WILL COVER THE FORECAST AREA MONDAY IN THE WAKE
OF THE DEPARTING SHORTWAVE TROUGH. SOME WEAK INSTABILITY AND
LINGERING MID-LEVEL MOISTURE NEAR THE COLORADO BORDER IN SWEETWATER
COUNTY DURING THE AFTERNOON AND EVENING. CONVECTION WOULD BE SHORT-
LIVED AND WEAK IF IT CAN MAKE MUCH PROGRESS OFF THE HIGHER TERRAIN
OF NORTHEAST UTAH. OTHERWISE...A DRY MONDAY WITH SEASONAL
TEMPERATURES AND LESS WIND THAT WHAT WILL BE SEEN THIS WEEKEND.
UPPER LEVEL FLOW BEGINS TO BACK TO THE SOUTHWEST ON TUESDAY IN
RESPONSE TO DEEPENING UPPER LEVEL LOW DIGGING INTO THE PACIFIC
NORTHWEST. THERE COULD BE ENOUGH MID-LEVEL MOISTURE TO INITIATE WEAK
MOUNTAIN CONVECTION TUESDAY THROUGH THURSDAY. THEREFORE...HAVE LEFT
LOW PRECIP CHANCES OVER MAINLY THE NORTHWEST MOUNTAINS. BELIEVE THAT
VERY LITTLE RAIN WOULD FALL WITH ANY CONVECTION THAT DEVELOPS AS DEW
POINTS WILL BE LESS THAN 40F AND PRECIPITABLE WATER VALUES LESS THAN
IMPRESSIVE. 700MB TEMPERATURES TUESDAY AND WEDNESDAY WILL AGAIN
APPROACH +15C WHICH WILL HAVE US STARING AT 90F SURFACE
TEMPERATURES. WOULD NOT BE SURPRISED TO SEE MAXIMUM TEMPERATURES
EXCEED 90F...ESPECIALLY ON WEDNESDAY AND MAYBE THURSDAY...DUE TO
INCREASING SOUTHWEST WIND AT THE SURFACE. THE MIDWEEK PATTERN...
BETWEEN TUESDAY AND THURSDAY...IS SHAPING UP TO BE ONE THAT COULD
HAVE CRITICAL FIRE WEATHER IMPLICATIONS. UNSEASONABLY WARM
TEMPERATURES...RELATIVE HUMIDITY IN THE TEENS...AND INCREASING
SOUTHWEST WIND AHEAD OF THE PACIFIC NORTHWEST TROUGH ALL LOOK TO BE
PRESENT ON THESE DAYS. IN FACT...DRIER SURFACE AIR WILL BE ADVECTED
INTO THE STATE FROM THE GREAT BASIN WITH AFTERNOON DEW POINTS
POSSIBLE FALLING TO LESS THAN 30F. THOSE WITH FIRE WEATHER INTERESTS
SHOULD CONTINUE TO MONITOR THE FORECAST FOR POSSIBLE HIGHLIGHTS.
APPROACH OF THE TROUGH WILL LEAD TO A BETTER OPPORTUNITY FOR
CONVECTION ACROSS THE NORTHWEST FRIDAY AFTERNOON AND EVENING. STILL
SOME DISCREPANCIES REGARDING HOW FAR SOUTH THE PACIFIC NORTHWEST
TROUGH WILL DIG AND HOW FAST IT WILL MOVE ACROSS THE FORECAST AREA.
BOTH ISSUES WILL HAVE AN IMPACT ON TEMPERATURES AND SENSIBLE WEATHER
HEADING INTO NEXT WEEKEND. COOLER AIR WILL SLIP SOUTH BEHIND A COLD
FRONT AND COOL THINGS DOWN FOR SATURDAY. FRIDAY TEMPERATURES WILL BE
MORE TRICKY AND DEPENDENT UPON THE TIMING OF THE COLD FRONTAL
PASSAGE. FORECAST FRIDAY TEMPERATURES EAST OF THE CONTINENTAL DIVIDE
COULD END UP BEING TOO COOL...BUT AT THIS RANGE HAVE NOT STRAYED
FROM KEEPING CONSISTENT REGIONAL FORECAST.

&&

.AVIATION.../06Z ISSUANCE/

A LINE OF THUNDERSTORMS WILL PUSH TO NEAR A VCNTY KJAC-KCOD LINE
THROUGH AROUND 07Z BEFORE DISSIPATING.  ERRATIC WIND GUSTS 30-40KTS
WILL BE THE MAIN HAZARD WITH THESE STORMS.  OTHERWISE ISOLD -SHRA/-
TSRA WILL CONTINUE VCNTY AND WEST OF THE DIVIDE OVERNIGHT.

A COLD FRONT WILL CONTINUE TO PUSH EAST ACROSS THE INTERMOUNTAIN
WEST ON SUNDAY WITH SFC SW FLOW INCREASING ACROSS WEST AND CENTRAL
WYOMING AHEAD OF THE FRONT...ALONG WITH AREAS OF LLWS.  SFC SW WINDS
AT 20-30KTS WILL PREVAIL ACROSS THE AREA LATE SUNDAY MORNING INTO
SUNDAY AFTERNOON.  THE MAIN AREA ISOLD-SCT -TSRA WILL DEVELOP VCNTY
AND SOUTH OF A KEVW-KLND-KCPR LINE AROUND 18Z SUNDAY WITH THIS AREA
SLOWLY PROPAGATING SOUTH AND EAST THROUGH THE AFTERNOON AND EARLY
EVENING.  THE COLD FRONT WILL BRING DRIER AIR AND GUSTY WEST WIND
INTO NW WYOMING MID TO LATE SUNDAY AFTERNOON...PUSHING ACROSS NORTH
AND CENTRAL WYOMING SUNDAY EVENING.  CLEAR SKIES AND DIMINISHING
WIND WILL PREVAIL ACROSS THE AREA BEHIND THE FRONT EARLY MONDAY
MORNING.

FIRE WEATHER...

.RED FLAG WARNING THROUGH SUNDAY FOR PORTIONS OF CENTRAL
WYOMING...

ON SUNDAY...OVERALL IT WILL BE WINDIER THAN IT WAS TODAY BUT WITH
SLIGHTLY HIGHER RELATIVE HUMIDITY. THE COLD FRONT ASSOCIATED WITH
THE TROUGH DIGGING TO THE WEST ADVANCES...IT WILL LIKELY SETTLE
INTO WESTERN...NORTHERN AND SOUTHERN WYOMING FAIRLY EARLY IN THE
DAY...WHICH WOULD END THE FIRE WEATHER THREAT IN THOSE LOCATIONS
ALONG WITH INCREASING CLOUDS AS WELL AS A SLIGHT CHANCE FOR A
WETTING RAIN. LATEST GUIDANCE CONTINUES TO SUGGEST THAT THE FRONT
WILL RETREAT BACK INTO MONTANA DURING THE LATE MORNING...CLEARING
THE WAY FOR MORE STRONG SOUTHWEST FLOW AND LOW HUMIDITY ACROSS
FREMONT...JOHNSON AND NATRONA COUNTIES. SO...THESE AREAS WILL
CONTINUE TO BE UNDER THE RED FLAG WARNING FOR SUNDAY. IN
ADDITION...A SWATH OF MID LEVEL MOISTURE AND CONTINUED INSTABILITY
WILL KICK OF A FEW MIXED WET AND DRY THUNDERSTORMS...SOME OF WHICH
COULD CONTRIBUTE TO NEW FIRE STARTS WITH THE MOST ACTIVITY
EXPECTED ACROSS NORTHERN AND WESTERN WYOMING...WITH A SECONDARY
SWATH EXPECTED OVER NATRONA AND EASTERN FREMONT COUNTIES LATE
SUNDAY AFTERNOON...THE CHANCE OF A WETTING RAIN OUT OF THESE
STORMS IS NEXT TO ZERO. THE BEST CHANCE OF ANY DRY LIGHTNING
STARTS WILL LIKELY BE ON THE PERIPHERY OF ANY THUNDERSTORMS OVER
NATRONA AND JOHNSON COUNTY WHERE THE COMBINATION OF DRIEST
BOUNDARY LEVEL MOISTURE...WIDEST TEMP/DEW POINT SPREADS AND
INSTABILITY WILL LIE ON SUNDAY AFTERNOON.

A REPEAT OF THESE CONDITIONS WILL BE POSSIBLE MID WEEK.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...
RED FLAG WARNING UNTIL 9 PM MDT THIS EVENING FOR WYZ275>277-279-
282-287-414>416.

RED FLAG WARNING UNTIL 9 PM MDT SUNDAY FOR WYZ280-281-283-285-
289-300.

&&

$$

SHORT TERM...ALLEN
LONG TERM...CNJ
AVIATION...AEM
FIRE WEATHER...ALLEN




000
FXUS65 KCYS 300534 AAB
AFDCYS

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE CHEYENNE WY
1134 PM MDT SAT AUG 29 2015

.UPDATE...FOR THE MIDNIGHT AVIATION FORECAST PACKAGE UPDATE.

&&

.SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT)
ISSUED AT 300 PM MDT SAT AUG 29 2015

FORECAST CHALLENGES DEAL WITH WINDS...PRECIPITATION CHANCES AND
POSSIBLE FIRE WEATHER CONCERNS THROUGH THE SHORT TERM.

CURRENTLY...LATEST VISIBLE SATELLITE IMAGERY FROM THIS MORNING
SHOWING ELEVATED SMOKE HANGING TOUGH OVER AREAS EAST OF THE
LARAMIE RANGE. LOW PRESSURE OFF THE COAST OF WASHINGTON STATE WITH
A FRONTAL SYSTEM BEING ANALYZED NEAR THE IDAHO/OREGON
BORDER...EXTENDING UP INTO ALBERTA CANADA. SOUTHEAST WYOMING
REMAINS UNDER AN UPPER RIDGE AXIS WITH FAIRLY LIGHT WINDS FOR THIS
PART OF THE COUNTRY.

RIDGE AXIS SHIFTS EAST THIS EVENING WITH 700MB SOUTHWESTERLY WINDS
INCREASING ACROSS CARBON AND ALBANY COUNTIES. AS HAS BEEN THE CASE
THE PAST WEEK...MODELS CONTINUE TO SHOW STRONG 850MB WINDS ACROSS
THE PANHANDLE THIS EVENING...UP TO 35-40KTS. COULD BE A LOW LEVEL
JET SETTING UP OUT THERE. FORECAST SOUNDINGS DO SHOW A LOW LEVEL
INVERSION SETTING UP THAT COULD SHELTER THE PANHANDLE FROM THESE
WINDS. BUT IF THE INVERSION DOES NOT SET UP...COULD BE DEALING
WITH ADVISORY LEVEL WINDS OUT THERE TONIGHT.

UPPER SHORTWAVE TROUGH MOVES INTO WESTERN MONTANA SUNDAY
AFTERNOON. STRONG 700MB WINDS OF 35-40KTS ACROSS CARBON AND ALBANY
COUNTIES AS WELL AS CONVERSE/NIOBRARA COUNTIES AND NORTH LARAMIE
RANGE. PRECIP DELAYED INTO THE AREA UNTIL LATE AFTERNOON...INTO
THE EVENING HOURS. DID UPGRADE THE FIRE WEATHER WATCH FOR
CONVERSE/NIOBRARA COUNTIES TO A RED FLAG WARNING THIS AFTERNOON. NIGHT
SHIFT WILL NEED TO CONSIDER NORTHERN 309 AND 310 AS WELL AS WE
SHOULD BE VERY DRY UP THERE WITH POOR OVERNIGHT HUMIDITY
RECOVERIES.

CONVECTION MOVES INTO OUR WESTERN ZONES LATE SUNDAY
AFTERNOON...PERSISTING INTO THE EVENING HOURS. GFS BY FAR THE
MOST BULLISH ON POPS OVER THE ECMWF AND NAM. DID DECREASE POPS
SOME FOR OUR EASTERN ZONES TOMORROW AFTERNOON.

LOOK FOR FRONTAL PASSAGE NEAR MIDNIGHT MONDAY MORNING WITH COOLER
AIR SPREADING INTO THE AREA FOR MONDAY.

.LONG TERM...(TUESDAY THROUGH SATURDAY)

ISSUED AT 338 PM MDT SAT AUG 29 2015

AFTER THE FRONTAL PASSAGE ON MONDAY... LINGERING MOISTURE ON
TUESDAY MAY CAUSE A FEW SHOWERS AND THUNDERSTORMS OVER THE SIERRA
MADRE AND SNOWY RANGES. GENERALLY SOUTHWESTERLY FLOW ALOFT WILL
PREVAIL FOR MOST OF THE CWA WITH AN UPPER LEVEL RIDGE BUILDING
OVERHEAD. THIS WILL BRING WARMER TEMPERATURES AND DRIER CONDITIONS
THROUGHOUT THE WEEK. WITH LACK OF ANY FORCING AND DRIER LOW LEVELS...
POP CHANCES WILL REMAIN LOW WEDNESDAY AND THURSDAY. FRIDAY THE
CHANCES FOR SHOWERS AND THUNDERSTORMS INCREASE WITH THE PASSAGE OF
AN UPPER LEVEL TROUGH... MAINLY EFFECTING EAST OF THE LARAMIE
RANGE INTO THE NEBRASKA PANHANDLE.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1134 PM MDT SAT AUG 29 2015

NO SIGNIFICANT AVIATION FORECAST CONCERNS OVERNIGHT. LIGHT TO
MODERATE SOUTHEASTERLY SURFACE WINDS WILL GRADUALLY VEER TO MORE
SOUTHWESTERLY THROUGH MID MORNING WITH A FEW PASSING HIGH LEVEL
CIRRUS CLOUDS OVERNIGHT. WINDS SHOULD PICK UP A BIT INTO THE 15-25
KT RANGE FROM THE SOUTHWEST FOR SOME SITES BY 17Z. IN SHORT VFR
CONDITIONS EXPECTED ALL SITES NEXT 24 HOURS.

&&

.FIRE WEATHER...
ISSUED AT 110 PM MDT SAT AUG 29 2015

INCREASING WINDS TONIGHT INTO SUNDAY AS LOW PRESSURE TRACKS INTO
MONTANA SUNDAY AFTERNOON. CHALLENGING FORECAST AS WIND SPEEDS
COULD BE OFFSET BY INCREASING CLOUDS...WHICH WOULD LIMIT MIXING.
WILL KEEP RED FLAG WARNING FOR FWZ 301 FOR SUNDAY LATE MORNING
THROUGH THE AFTERNOON. INCREASING MOISTURE SUNDAY AFTERNOON ACROSS
CARBON AND ALBANY COUNTIES WILL GIVE CHANCES FOR WETTING RAINS OUT
THAT WAY FROM MID AFTERNOON THROUGH MID EVENING. WINDY PERIOD

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...RED FLAG WARNING FROM 11 AM TO 7 PM MDT SUNDAY FOR WYZ301.

NE...NONE.
&&

$$

SHORT TERM...GCC
LONG TERM...SML/KC
AVIATION...JG
FIRE WEATHER...GCC



000
FXUS65 KCYS 300534 AAB
AFDCYS

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE CHEYENNE WY
1134 PM MDT SAT AUG 29 2015

.UPDATE...FOR THE MIDNIGHT AVIATION FORECAST PACKAGE UPDATE.

&&

.SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT)
ISSUED AT 300 PM MDT SAT AUG 29 2015

FORECAST CHALLENGES DEAL WITH WINDS...PRECIPITATION CHANCES AND
POSSIBLE FIRE WEATHER CONCERNS THROUGH THE SHORT TERM.

CURRENTLY...LATEST VISIBLE SATELLITE IMAGERY FROM THIS MORNING
SHOWING ELEVATED SMOKE HANGING TOUGH OVER AREAS EAST OF THE
LARAMIE RANGE. LOW PRESSURE OFF THE COAST OF WASHINGTON STATE WITH
A FRONTAL SYSTEM BEING ANALYZED NEAR THE IDAHO/OREGON
BORDER...EXTENDING UP INTO ALBERTA CANADA. SOUTHEAST WYOMING
REMAINS UNDER AN UPPER RIDGE AXIS WITH FAIRLY LIGHT WINDS FOR THIS
PART OF THE COUNTRY.

RIDGE AXIS SHIFTS EAST THIS EVENING WITH 700MB SOUTHWESTERLY WINDS
INCREASING ACROSS CARBON AND ALBANY COUNTIES. AS HAS BEEN THE CASE
THE PAST WEEK...MODELS CONTINUE TO SHOW STRONG 850MB WINDS ACROSS
THE PANHANDLE THIS EVENING...UP TO 35-40KTS. COULD BE A LOW LEVEL
JET SETTING UP OUT THERE. FORECAST SOUNDINGS DO SHOW A LOW LEVEL
INVERSION SETTING UP THAT COULD SHELTER THE PANHANDLE FROM THESE
WINDS. BUT IF THE INVERSION DOES NOT SET UP...COULD BE DEALING
WITH ADVISORY LEVEL WINDS OUT THERE TONIGHT.

UPPER SHORTWAVE TROUGH MOVES INTO WESTERN MONTANA SUNDAY
AFTERNOON. STRONG 700MB WINDS OF 35-40KTS ACROSS CARBON AND ALBANY
COUNTIES AS WELL AS CONVERSE/NIOBRARA COUNTIES AND NORTH LARAMIE
RANGE. PRECIP DELAYED INTO THE AREA UNTIL LATE AFTERNOON...INTO
THE EVENING HOURS. DID UPGRADE THE FIRE WEATHER WATCH FOR
CONVERSE/NIOBRARA COUNTIES TO A RED FLAG WARNING THIS AFTERNOON. NIGHT
SHIFT WILL NEED TO CONSIDER NORTHERN 309 AND 310 AS WELL AS WE
SHOULD BE VERY DRY UP THERE WITH POOR OVERNIGHT HUMIDITY
RECOVERIES.

CONVECTION MOVES INTO OUR WESTERN ZONES LATE SUNDAY
AFTERNOON...PERSISTING INTO THE EVENING HOURS. GFS BY FAR THE
MOST BULLISH ON POPS OVER THE ECMWF AND NAM. DID DECREASE POPS
SOME FOR OUR EASTERN ZONES TOMORROW AFTERNOON.

LOOK FOR FRONTAL PASSAGE NEAR MIDNIGHT MONDAY MORNING WITH COOLER
AIR SPREADING INTO THE AREA FOR MONDAY.

.LONG TERM...(TUESDAY THROUGH SATURDAY)

ISSUED AT 338 PM MDT SAT AUG 29 2015

AFTER THE FRONTAL PASSAGE ON MONDAY... LINGERING MOISTURE ON
TUESDAY MAY CAUSE A FEW SHOWERS AND THUNDERSTORMS OVER THE SIERRA
MADRE AND SNOWY RANGES. GENERALLY SOUTHWESTERLY FLOW ALOFT WILL
PREVAIL FOR MOST OF THE CWA WITH AN UPPER LEVEL RIDGE BUILDING
OVERHEAD. THIS WILL BRING WARMER TEMPERATURES AND DRIER CONDITIONS
THROUGHOUT THE WEEK. WITH LACK OF ANY FORCING AND DRIER LOW LEVELS...
POP CHANCES WILL REMAIN LOW WEDNESDAY AND THURSDAY. FRIDAY THE
CHANCES FOR SHOWERS AND THUNDERSTORMS INCREASE WITH THE PASSAGE OF
AN UPPER LEVEL TROUGH... MAINLY EFFECTING EAST OF THE LARAMIE
RANGE INTO THE NEBRASKA PANHANDLE.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1134 PM MDT SAT AUG 29 2015

NO SIGNIFICANT AVIATION FORECAST CONCERNS OVERNIGHT. LIGHT TO
MODERATE SOUTHEASTERLY SURFACE WINDS WILL GRADUALLY VEER TO MORE
SOUTHWESTERLY THROUGH MID MORNING WITH A FEW PASSING HIGH LEVEL
CIRRUS CLOUDS OVERNIGHT. WINDS SHOULD PICK UP A BIT INTO THE 15-25
KT RANGE FROM THE SOUTHWEST FOR SOME SITES BY 17Z. IN SHORT VFR
CONDITIONS EXPECTED ALL SITES NEXT 24 HOURS.

&&

.FIRE WEATHER...
ISSUED AT 110 PM MDT SAT AUG 29 2015

INCREASING WINDS TONIGHT INTO SUNDAY AS LOW PRESSURE TRACKS INTO
MONTANA SUNDAY AFTERNOON. CHALLENGING FORECAST AS WIND SPEEDS
COULD BE OFFSET BY INCREASING CLOUDS...WHICH WOULD LIMIT MIXING.
WILL KEEP RED FLAG WARNING FOR FWZ 301 FOR SUNDAY LATE MORNING
THROUGH THE AFTERNOON. INCREASING MOISTURE SUNDAY AFTERNOON ACROSS
CARBON AND ALBANY COUNTIES WILL GIVE CHANCES FOR WETTING RAINS OUT
THAT WAY FROM MID AFTERNOON THROUGH MID EVENING. WINDY PERIOD

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...RED FLAG WARNING FROM 11 AM TO 7 PM MDT SUNDAY FOR WYZ301.

NE...NONE.
&&

$$

SHORT TERM...GCC
LONG TERM...SML/KC
AVIATION...JG
FIRE WEATHER...GCC




000
FXUS65 KCYS 300534 AAB
AFDCYS

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE CHEYENNE WY
1134 PM MDT SAT AUG 29 2015

.UPDATE...FOR THE MIDNIGHT AVIATION FORECAST PACKAGE UPDATE.

&&

.SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT)
ISSUED AT 300 PM MDT SAT AUG 29 2015

FORECAST CHALLENGES DEAL WITH WINDS...PRECIPITATION CHANCES AND
POSSIBLE FIRE WEATHER CONCERNS THROUGH THE SHORT TERM.

CURRENTLY...LATEST VISIBLE SATELLITE IMAGERY FROM THIS MORNING
SHOWING ELEVATED SMOKE HANGING TOUGH OVER AREAS EAST OF THE
LARAMIE RANGE. LOW PRESSURE OFF THE COAST OF WASHINGTON STATE WITH
A FRONTAL SYSTEM BEING ANALYZED NEAR THE IDAHO/OREGON
BORDER...EXTENDING UP INTO ALBERTA CANADA. SOUTHEAST WYOMING
REMAINS UNDER AN UPPER RIDGE AXIS WITH FAIRLY LIGHT WINDS FOR THIS
PART OF THE COUNTRY.

RIDGE AXIS SHIFTS EAST THIS EVENING WITH 700MB SOUTHWESTERLY WINDS
INCREASING ACROSS CARBON AND ALBANY COUNTIES. AS HAS BEEN THE CASE
THE PAST WEEK...MODELS CONTINUE TO SHOW STRONG 850MB WINDS ACROSS
THE PANHANDLE THIS EVENING...UP TO 35-40KTS. COULD BE A LOW LEVEL
JET SETTING UP OUT THERE. FORECAST SOUNDINGS DO SHOW A LOW LEVEL
INVERSION SETTING UP THAT COULD SHELTER THE PANHANDLE FROM THESE
WINDS. BUT IF THE INVERSION DOES NOT SET UP...COULD BE DEALING
WITH ADVISORY LEVEL WINDS OUT THERE TONIGHT.

UPPER SHORTWAVE TROUGH MOVES INTO WESTERN MONTANA SUNDAY
AFTERNOON. STRONG 700MB WINDS OF 35-40KTS ACROSS CARBON AND ALBANY
COUNTIES AS WELL AS CONVERSE/NIOBRARA COUNTIES AND NORTH LARAMIE
RANGE. PRECIP DELAYED INTO THE AREA UNTIL LATE AFTERNOON...INTO
THE EVENING HOURS. DID UPGRADE THE FIRE WEATHER WATCH FOR
CONVERSE/NIOBRARA COUNTIES TO A RED FLAG WARNING THIS AFTERNOON. NIGHT
SHIFT WILL NEED TO CONSIDER NORTHERN 309 AND 310 AS WELL AS WE
SHOULD BE VERY DRY UP THERE WITH POOR OVERNIGHT HUMIDITY
RECOVERIES.

CONVECTION MOVES INTO OUR WESTERN ZONES LATE SUNDAY
AFTERNOON...PERSISTING INTO THE EVENING HOURS. GFS BY FAR THE
MOST BULLISH ON POPS OVER THE ECMWF AND NAM. DID DECREASE POPS
SOME FOR OUR EASTERN ZONES TOMORROW AFTERNOON.

LOOK FOR FRONTAL PASSAGE NEAR MIDNIGHT MONDAY MORNING WITH COOLER
AIR SPREADING INTO THE AREA FOR MONDAY.

.LONG TERM...(TUESDAY THROUGH SATURDAY)

ISSUED AT 338 PM MDT SAT AUG 29 2015

AFTER THE FRONTAL PASSAGE ON MONDAY... LINGERING MOISTURE ON
TUESDAY MAY CAUSE A FEW SHOWERS AND THUNDERSTORMS OVER THE SIERRA
MADRE AND SNOWY RANGES. GENERALLY SOUTHWESTERLY FLOW ALOFT WILL
PREVAIL FOR MOST OF THE CWA WITH AN UPPER LEVEL RIDGE BUILDING
OVERHEAD. THIS WILL BRING WARMER TEMPERATURES AND DRIER CONDITIONS
THROUGHOUT THE WEEK. WITH LACK OF ANY FORCING AND DRIER LOW LEVELS...
POP CHANCES WILL REMAIN LOW WEDNESDAY AND THURSDAY. FRIDAY THE
CHANCES FOR SHOWERS AND THUNDERSTORMS INCREASE WITH THE PASSAGE OF
AN UPPER LEVEL TROUGH... MAINLY EFFECTING EAST OF THE LARAMIE
RANGE INTO THE NEBRASKA PANHANDLE.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1134 PM MDT SAT AUG 29 2015

NO SIGNIFICANT AVIATION FORECAST CONCERNS OVERNIGHT. LIGHT TO
MODERATE SOUTHEASTERLY SURFACE WINDS WILL GRADUALLY VEER TO MORE
SOUTHWESTERLY THROUGH MID MORNING WITH A FEW PASSING HIGH LEVEL
CIRRUS CLOUDS OVERNIGHT. WINDS SHOULD PICK UP A BIT INTO THE 15-25
KT RANGE FROM THE SOUTHWEST FOR SOME SITES BY 17Z. IN SHORT VFR
CONDITIONS EXPECTED ALL SITES NEXT 24 HOURS.

&&

.FIRE WEATHER...
ISSUED AT 110 PM MDT SAT AUG 29 2015

INCREASING WINDS TONIGHT INTO SUNDAY AS LOW PRESSURE TRACKS INTO
MONTANA SUNDAY AFTERNOON. CHALLENGING FORECAST AS WIND SPEEDS
COULD BE OFFSET BY INCREASING CLOUDS...WHICH WOULD LIMIT MIXING.
WILL KEEP RED FLAG WARNING FOR FWZ 301 FOR SUNDAY LATE MORNING
THROUGH THE AFTERNOON. INCREASING MOISTURE SUNDAY AFTERNOON ACROSS
CARBON AND ALBANY COUNTIES WILL GIVE CHANCES FOR WETTING RAINS OUT
THAT WAY FROM MID AFTERNOON THROUGH MID EVENING. WINDY PERIOD

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...RED FLAG WARNING FROM 11 AM TO 7 PM MDT SUNDAY FOR WYZ301.

NE...NONE.
&&

$$

SHORT TERM...GCC
LONG TERM...SML/KC
AVIATION...JG
FIRE WEATHER...GCC




000
FXUS65 KCYS 300534 AAB
AFDCYS

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE CHEYENNE WY
1134 PM MDT SAT AUG 29 2015

.UPDATE...FOR THE MIDNIGHT AVIATION FORECAST PACKAGE UPDATE.

&&

.SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT)
ISSUED AT 300 PM MDT SAT AUG 29 2015

FORECAST CHALLENGES DEAL WITH WINDS...PRECIPITATION CHANCES AND
POSSIBLE FIRE WEATHER CONCERNS THROUGH THE SHORT TERM.

CURRENTLY...LATEST VISIBLE SATELLITE IMAGERY FROM THIS MORNING
SHOWING ELEVATED SMOKE HANGING TOUGH OVER AREAS EAST OF THE
LARAMIE RANGE. LOW PRESSURE OFF THE COAST OF WASHINGTON STATE WITH
A FRONTAL SYSTEM BEING ANALYZED NEAR THE IDAHO/OREGON
BORDER...EXTENDING UP INTO ALBERTA CANADA. SOUTHEAST WYOMING
REMAINS UNDER AN UPPER RIDGE AXIS WITH FAIRLY LIGHT WINDS FOR THIS
PART OF THE COUNTRY.

RIDGE AXIS SHIFTS EAST THIS EVENING WITH 700MB SOUTHWESTERLY WINDS
INCREASING ACROSS CARBON AND ALBANY COUNTIES. AS HAS BEEN THE CASE
THE PAST WEEK...MODELS CONTINUE TO SHOW STRONG 850MB WINDS ACROSS
THE PANHANDLE THIS EVENING...UP TO 35-40KTS. COULD BE A LOW LEVEL
JET SETTING UP OUT THERE. FORECAST SOUNDINGS DO SHOW A LOW LEVEL
INVERSION SETTING UP THAT COULD SHELTER THE PANHANDLE FROM THESE
WINDS. BUT IF THE INVERSION DOES NOT SET UP...COULD BE DEALING
WITH ADVISORY LEVEL WINDS OUT THERE TONIGHT.

UPPER SHORTWAVE TROUGH MOVES INTO WESTERN MONTANA SUNDAY
AFTERNOON. STRONG 700MB WINDS OF 35-40KTS ACROSS CARBON AND ALBANY
COUNTIES AS WELL AS CONVERSE/NIOBRARA COUNTIES AND NORTH LARAMIE
RANGE. PRECIP DELAYED INTO THE AREA UNTIL LATE AFTERNOON...INTO
THE EVENING HOURS. DID UPGRADE THE FIRE WEATHER WATCH FOR
CONVERSE/NIOBRARA COUNTIES TO A RED FLAG WARNING THIS AFTERNOON. NIGHT
SHIFT WILL NEED TO CONSIDER NORTHERN 309 AND 310 AS WELL AS WE
SHOULD BE VERY DRY UP THERE WITH POOR OVERNIGHT HUMIDITY
RECOVERIES.

CONVECTION MOVES INTO OUR WESTERN ZONES LATE SUNDAY
AFTERNOON...PERSISTING INTO THE EVENING HOURS. GFS BY FAR THE
MOST BULLISH ON POPS OVER THE ECMWF AND NAM. DID DECREASE POPS
SOME FOR OUR EASTERN ZONES TOMORROW AFTERNOON.

LOOK FOR FRONTAL PASSAGE NEAR MIDNIGHT MONDAY MORNING WITH COOLER
AIR SPREADING INTO THE AREA FOR MONDAY.

.LONG TERM...(TUESDAY THROUGH SATURDAY)

ISSUED AT 338 PM MDT SAT AUG 29 2015

AFTER THE FRONTAL PASSAGE ON MONDAY... LINGERING MOISTURE ON
TUESDAY MAY CAUSE A FEW SHOWERS AND THUNDERSTORMS OVER THE SIERRA
MADRE AND SNOWY RANGES. GENERALLY SOUTHWESTERLY FLOW ALOFT WILL
PREVAIL FOR MOST OF THE CWA WITH AN UPPER LEVEL RIDGE BUILDING
OVERHEAD. THIS WILL BRING WARMER TEMPERATURES AND DRIER CONDITIONS
THROUGHOUT THE WEEK. WITH LACK OF ANY FORCING AND DRIER LOW LEVELS...
POP CHANCES WILL REMAIN LOW WEDNESDAY AND THURSDAY. FRIDAY THE
CHANCES FOR SHOWERS AND THUNDERSTORMS INCREASE WITH THE PASSAGE OF
AN UPPER LEVEL TROUGH... MAINLY EFFECTING EAST OF THE LARAMIE
RANGE INTO THE NEBRASKA PANHANDLE.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1134 PM MDT SAT AUG 29 2015

NO SIGNIFICANT AVIATION FORECAST CONCERNS OVERNIGHT. LIGHT TO
MODERATE SOUTHEASTERLY SURFACE WINDS WILL GRADUALLY VEER TO MORE
SOUTHWESTERLY THROUGH MID MORNING WITH A FEW PASSING HIGH LEVEL
CIRRUS CLOUDS OVERNIGHT. WINDS SHOULD PICK UP A BIT INTO THE 15-25
KT RANGE FROM THE SOUTHWEST FOR SOME SITES BY 17Z. IN SHORT VFR
CONDITIONS EXPECTED ALL SITES NEXT 24 HOURS.

&&

.FIRE WEATHER...
ISSUED AT 110 PM MDT SAT AUG 29 2015

INCREASING WINDS TONIGHT INTO SUNDAY AS LOW PRESSURE TRACKS INTO
MONTANA SUNDAY AFTERNOON. CHALLENGING FORECAST AS WIND SPEEDS
COULD BE OFFSET BY INCREASING CLOUDS...WHICH WOULD LIMIT MIXING.
WILL KEEP RED FLAG WARNING FOR FWZ 301 FOR SUNDAY LATE MORNING
THROUGH THE AFTERNOON. INCREASING MOISTURE SUNDAY AFTERNOON ACROSS
CARBON AND ALBANY COUNTIES WILL GIVE CHANCES FOR WETTING RAINS OUT
THAT WAY FROM MID AFTERNOON THROUGH MID EVENING. WINDY PERIOD

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...RED FLAG WARNING FROM 11 AM TO 7 PM MDT SUNDAY FOR WYZ301.

NE...NONE.
&&

$$

SHORT TERM...GCC
LONG TERM...SML/KC
AVIATION...JG
FIRE WEATHER...GCC



000
FXUS63 KUNR 300525
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
1125 PM MDT SAT AUG 29 2015

.SHORT TERM...THIS EVENING THROUGH SUNDAY NIGHT
ISSUED AT 258 PM MDT SAT AUG 29 2015

CURRENT SURFACE ANALYSIS SHOWS LOW PRESSURE OVER SK...WITH A COLD
FRONT TRAILING SOUTHWESTWARD INTO NORTHWEST MT AND NORTHERN ID. A
SURFACE TROF EXTENDS SOUTHWARD ACROSS EASTERN MT INTO NORTHEAST
WY. UPPER LEVEL ANALYSIS SHOWS RIDGING OVER THE ROCKIES AND INTO
THE HIGH PLAINS. FLOW ALOFT HAS BECOME WESTERLY OVER THE AREA AND
WILL BECOME SOUTHWESTERLY INTO TONIGHT. TEMPS ARE IN THE 90S
ACROSS THE PLAINS...WITH 80S IN THE BLACK HILLS. WINDS ARE SOUTH
TO SOUTHWEST...BREEZY ACROSS PORTIONS OF NORTHEAST WY. HAZY
SUNSHINE CONTINUES THROUGH THE SMOKE...THOUGH CONDITIONS APPEAR TO
BE GRADUALLY IMPROVING IN MOST AREAS THIS AFTERNOON.

AS RIDGE BUILDS OVER AND EAST OF THE AREA THROUGH THE WEEKEND...HOT
CONDITIONS CAN BE EXPECTED. THE COLD FRONT TO THE NORTHWEST OF THE
REGION WILL EVENTUALLY MAKE IT INTO THE FORECAST AREA LATE SUNDAY
AND SUNDAY NIGHT...BRINGING MOSTLY ISOLATED SHOWERS AND
THUNDERSTORMS...ALONG WITH COOLER AND BREEZY CONDITIONS BEHIND IT
INTO MONDAY.

FOR TONIGHT...SKIES WILL STAY MAINLY CLEAR WITH LOWS MOSTLY IN THE
60S TO AROUND 70 DEGREES. LOW LEVEL SOUTHERLY JET WILL INTENSIFY
OVER THE AREA OVERNIGHT...WITH BREEZY CONDITIONS AT TIMES IN THE
USUAL AREAS FROM NORTHEAST WY THROUGH SOUTHWEST INTO SOUTH CENTRAL
SD. ATMOSPHERE LOOKS TOO DRY TO GET ANY SHOWERS TO DEVELOP WITH THE
JET.

SUNDAY WILL SEE MOSTLY SUNNY TO PARTLY CLOUDY SKIES WITH HIGHS IN
THE 90S TO AROUND 100 DEGREES ON THE PLAINS AS THE THERMAL RIDGE
MOVES ACROSS WESTERN INTO CENTRAL SD DURING THE DAY. EXACT TIMING OF
THE COLD FRONT IS STILL A BIT UNCERTAIN...BUT IT SHOULD MOVE INTO
NORTHEAST WY LATE IN THE DAY AND ACROSS THE REST OF THE FORECAST
AREA SUNDAY NIGHT. WINDS WILL SWITCH TO THE WEST-NORTHWEST AND
BECOME BREEZY TO WINDY ACROSS NORTHWEST INTO WEST CENTRAL SD
OVERNIGHT. EMBEDDED ENERGY IN SOUTHWEST FLOW ALOFT WILL COMBINE WITH
THE FRONT TO PRODUCE AT LEAST ISOLATED SHOWERS AND STORMS OVER A
GOOD PORTION OF THE CWA SUNDAY NIGHT. THE THREAT FOR STRONG TO
SEVERE STORMS IS MINIMAL WITH THE TIMING OF THE FRONT...THOUGH WINDS
COULD GET GUSTY WITH SOME OF THE SHOWERS BEHIND THE FRONT.

.LONG TERM...MONDAY THROUGH SATURDAY
ISSUED AT 258 PM MDT SAT AUG 29 2015

NEGATIVE HEIGHT ANOMALY OVER THE PAC NW WILL REMAIN NEARLY
STATIONARY THROUGH THE PERIOD...WITH GENERALLY WARM CONDS OVER THE
NORTHERN PLAINS AS UPPER LEVEL SW FLOW PERSISTS. THE WESTERN NOAM
UPPER TROUGH WILL GRADUALLY SHIFT EAST AS A STRONGER NORTHERN
STREAM IMPULSE MERGES WITH IT...LEADING TOWARD BREAKDOWN OF THE
PERSISTENT RIDGE. IN THE MEANTIME...ABOVE NORMAL TEMPS WILL
PERSIST THROUGH MOST OF THE PERIOD...WITH MAINLY DRY CONDS. WEAK
COLD FRONT WILL ADVECT THROUGH THE AREA MONDAY MORNING...
SUPPORTING COOLER BUT STILL SEASONAL TEMPS IN A CAA REGIME MONDAY.
CENTRAL NOAM RIDGE WILL RE-SURGE TUE-THUR...WITH VERY WARM CONDS
EXPECTED ONCE AGAIN AS SOUTHERLY FLOW SPREADS OVER THE REGION.
WEAK SW FLOW IMPULSES COULD SUPPORT A FEW ISOLD SHRA/TS IN THE
TUE-WED PERIOD...ESP WITH ANY CONCENTRATED POS THETA-E ADV.
HOWEVER...LACK OF ANY APPRECIABLE SIGNALS PRECLUDE ANY POP
MENTION. NW PAC UPPER TROUGH WILL BIAS EAST BY THE END OF THE WEEK
WITH COOLER WEATHER LOOKING MORE LIKELY WITH INCREASING CHANCES
FOR RAIN.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1124 PM MDT SAT AUG 29 2015

VFR CONDITIONS WILL PREVAIL THROUGH SUNDAY AFTERNOON. LOW LEVEL
WIND SHEAR IS EXPECTED ON THE SD PLAINS THROUGH SUNDAY MORNING AS
A LOW LEVEL JET FROM 30-40KTS OCCURS. ISOLATED -TSRA POSSIBLE
OVER THE FAR WEST LATE SUNDAY AFTERNOON/EVENING.

&&

.FIRE WEATHER...
ISSUED AT 258 PM MDT SAT AUG 29 2015

WARM AND DRY CONDS WILL PERSIST ACROSS NE WY. RELATIVE HUMIDITY
ACROSS PORTIONS OF THE NORTHEAST WYOMING PLAINS WILL DROP TO 15
PERCENT OR BELOW THIS AFTERNOON AND AGAIN SUNDAY AFTERNOON. GUSTY
SOUTHWEST WINDS WILL CONTINUE THROUGH SUNDAY...AND ARE EXPECTED TO
BE STRONGEST SUNDAY AFTERNOON AHEAD OF A COLD FRONT. SW WINDS OF
20 TO 30 MPH WITH GUSTS TO AROUND 35 MPH ARE EXPECTED SUN.
PARTIALLY MIXED CONDS CAN BE EXPECTED TONIGHT GIVEN PRESSURE
FALLS...WITH SW WINDS CONTINUING UNDER POOR RH RECOVERY. WENT
AHEAD AND EXTENDED THE RED FLAG WARNING THROUGH SUNDAY AFTERNOON
FOR THIS.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
WY...RED FLAG WARNING UNTIL 8 PM MDT SUNDAY FOR WYZ259-297-298.

&&

$$

SHORT TERM...26
LONG TERM...JC
AVIATION...HELGESON
FIRE WEATHER...JC



000
FXUS63 KUNR 300525
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
1125 PM MDT SAT AUG 29 2015

.SHORT TERM...THIS EVENING THROUGH SUNDAY NIGHT
ISSUED AT 258 PM MDT SAT AUG 29 2015

CURRENT SURFACE ANALYSIS SHOWS LOW PRESSURE OVER SK...WITH A COLD
FRONT TRAILING SOUTHWESTWARD INTO NORTHWEST MT AND NORTHERN ID. A
SURFACE TROF EXTENDS SOUTHWARD ACROSS EASTERN MT INTO NORTHEAST
WY. UPPER LEVEL ANALYSIS SHOWS RIDGING OVER THE ROCKIES AND INTO
THE HIGH PLAINS. FLOW ALOFT HAS BECOME WESTERLY OVER THE AREA AND
WILL BECOME SOUTHWESTERLY INTO TONIGHT. TEMPS ARE IN THE 90S
ACROSS THE PLAINS...WITH 80S IN THE BLACK HILLS. WINDS ARE SOUTH
TO SOUTHWEST...BREEZY ACROSS PORTIONS OF NORTHEAST WY. HAZY
SUNSHINE CONTINUES THROUGH THE SMOKE...THOUGH CONDITIONS APPEAR TO
BE GRADUALLY IMPROVING IN MOST AREAS THIS AFTERNOON.

AS RIDGE BUILDS OVER AND EAST OF THE AREA THROUGH THE WEEKEND...HOT
CONDITIONS CAN BE EXPECTED. THE COLD FRONT TO THE NORTHWEST OF THE
REGION WILL EVENTUALLY MAKE IT INTO THE FORECAST AREA LATE SUNDAY
AND SUNDAY NIGHT...BRINGING MOSTLY ISOLATED SHOWERS AND
THUNDERSTORMS...ALONG WITH COOLER AND BREEZY CONDITIONS BEHIND IT
INTO MONDAY.

FOR TONIGHT...SKIES WILL STAY MAINLY CLEAR WITH LOWS MOSTLY IN THE
60S TO AROUND 70 DEGREES. LOW LEVEL SOUTHERLY JET WILL INTENSIFY
OVER THE AREA OVERNIGHT...WITH BREEZY CONDITIONS AT TIMES IN THE
USUAL AREAS FROM NORTHEAST WY THROUGH SOUTHWEST INTO SOUTH CENTRAL
SD. ATMOSPHERE LOOKS TOO DRY TO GET ANY SHOWERS TO DEVELOP WITH THE
JET.

SUNDAY WILL SEE MOSTLY SUNNY TO PARTLY CLOUDY SKIES WITH HIGHS IN
THE 90S TO AROUND 100 DEGREES ON THE PLAINS AS THE THERMAL RIDGE
MOVES ACROSS WESTERN INTO CENTRAL SD DURING THE DAY. EXACT TIMING OF
THE COLD FRONT IS STILL A BIT UNCERTAIN...BUT IT SHOULD MOVE INTO
NORTHEAST WY LATE IN THE DAY AND ACROSS THE REST OF THE FORECAST
AREA SUNDAY NIGHT. WINDS WILL SWITCH TO THE WEST-NORTHWEST AND
BECOME BREEZY TO WINDY ACROSS NORTHWEST INTO WEST CENTRAL SD
OVERNIGHT. EMBEDDED ENERGY IN SOUTHWEST FLOW ALOFT WILL COMBINE WITH
THE FRONT TO PRODUCE AT LEAST ISOLATED SHOWERS AND STORMS OVER A
GOOD PORTION OF THE CWA SUNDAY NIGHT. THE THREAT FOR STRONG TO
SEVERE STORMS IS MINIMAL WITH THE TIMING OF THE FRONT...THOUGH WINDS
COULD GET GUSTY WITH SOME OF THE SHOWERS BEHIND THE FRONT.

.LONG TERM...MONDAY THROUGH SATURDAY
ISSUED AT 258 PM MDT SAT AUG 29 2015

NEGATIVE HEIGHT ANOMALY OVER THE PAC NW WILL REMAIN NEARLY
STATIONARY THROUGH THE PERIOD...WITH GENERALLY WARM CONDS OVER THE
NORTHERN PLAINS AS UPPER LEVEL SW FLOW PERSISTS. THE WESTERN NOAM
UPPER TROUGH WILL GRADUALLY SHIFT EAST AS A STRONGER NORTHERN
STREAM IMPULSE MERGES WITH IT...LEADING TOWARD BREAKDOWN OF THE
PERSISTENT RIDGE. IN THE MEANTIME...ABOVE NORMAL TEMPS WILL
PERSIST THROUGH MOST OF THE PERIOD...WITH MAINLY DRY CONDS. WEAK
COLD FRONT WILL ADVECT THROUGH THE AREA MONDAY MORNING...
SUPPORTING COOLER BUT STILL SEASONAL TEMPS IN A CAA REGIME MONDAY.
CENTRAL NOAM RIDGE WILL RE-SURGE TUE-THUR...WITH VERY WARM CONDS
EXPECTED ONCE AGAIN AS SOUTHERLY FLOW SPREADS OVER THE REGION.
WEAK SW FLOW IMPULSES COULD SUPPORT A FEW ISOLD SHRA/TS IN THE
TUE-WED PERIOD...ESP WITH ANY CONCENTRATED POS THETA-E ADV.
HOWEVER...LACK OF ANY APPRECIABLE SIGNALS PRECLUDE ANY POP
MENTION. NW PAC UPPER TROUGH WILL BIAS EAST BY THE END OF THE WEEK
WITH COOLER WEATHER LOOKING MORE LIKELY WITH INCREASING CHANCES
FOR RAIN.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1124 PM MDT SAT AUG 29 2015

VFR CONDITIONS WILL PREVAIL THROUGH SUNDAY AFTERNOON. LOW LEVEL
WIND SHEAR IS EXPECTED ON THE SD PLAINS THROUGH SUNDAY MORNING AS
A LOW LEVEL JET FROM 30-40KTS OCCURS. ISOLATED -TSRA POSSIBLE
OVER THE FAR WEST LATE SUNDAY AFTERNOON/EVENING.

&&

.FIRE WEATHER...
ISSUED AT 258 PM MDT SAT AUG 29 2015

WARM AND DRY CONDS WILL PERSIST ACROSS NE WY. RELATIVE HUMIDITY
ACROSS PORTIONS OF THE NORTHEAST WYOMING PLAINS WILL DROP TO 15
PERCENT OR BELOW THIS AFTERNOON AND AGAIN SUNDAY AFTERNOON. GUSTY
SOUTHWEST WINDS WILL CONTINUE THROUGH SUNDAY...AND ARE EXPECTED TO
BE STRONGEST SUNDAY AFTERNOON AHEAD OF A COLD FRONT. SW WINDS OF
20 TO 30 MPH WITH GUSTS TO AROUND 35 MPH ARE EXPECTED SUN.
PARTIALLY MIXED CONDS CAN BE EXPECTED TONIGHT GIVEN PRESSURE
FALLS...WITH SW WINDS CONTINUING UNDER POOR RH RECOVERY. WENT
AHEAD AND EXTENDED THE RED FLAG WARNING THROUGH SUNDAY AFTERNOON
FOR THIS.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
WY...RED FLAG WARNING UNTIL 8 PM MDT SUNDAY FOR WYZ259-297-298.

&&

$$

SHORT TERM...26
LONG TERM...JC
AVIATION...HELGESON
FIRE WEATHER...JC



000
FXUS63 KUNR 300525
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
1125 PM MDT SAT AUG 29 2015

.SHORT TERM...THIS EVENING THROUGH SUNDAY NIGHT
ISSUED AT 258 PM MDT SAT AUG 29 2015

CURRENT SURFACE ANALYSIS SHOWS LOW PRESSURE OVER SK...WITH A COLD
FRONT TRAILING SOUTHWESTWARD INTO NORTHWEST MT AND NORTHERN ID. A
SURFACE TROF EXTENDS SOUTHWARD ACROSS EASTERN MT INTO NORTHEAST
WY. UPPER LEVEL ANALYSIS SHOWS RIDGING OVER THE ROCKIES AND INTO
THE HIGH PLAINS. FLOW ALOFT HAS BECOME WESTERLY OVER THE AREA AND
WILL BECOME SOUTHWESTERLY INTO TONIGHT. TEMPS ARE IN THE 90S
ACROSS THE PLAINS...WITH 80S IN THE BLACK HILLS. WINDS ARE SOUTH
TO SOUTHWEST...BREEZY ACROSS PORTIONS OF NORTHEAST WY. HAZY
SUNSHINE CONTINUES THROUGH THE SMOKE...THOUGH CONDITIONS APPEAR TO
BE GRADUALLY IMPROVING IN MOST AREAS THIS AFTERNOON.

AS RIDGE BUILDS OVER AND EAST OF THE AREA THROUGH THE WEEKEND...HOT
CONDITIONS CAN BE EXPECTED. THE COLD FRONT TO THE NORTHWEST OF THE
REGION WILL EVENTUALLY MAKE IT INTO THE FORECAST AREA LATE SUNDAY
AND SUNDAY NIGHT...BRINGING MOSTLY ISOLATED SHOWERS AND
THUNDERSTORMS...ALONG WITH COOLER AND BREEZY CONDITIONS BEHIND IT
INTO MONDAY.

FOR TONIGHT...SKIES WILL STAY MAINLY CLEAR WITH LOWS MOSTLY IN THE
60S TO AROUND 70 DEGREES. LOW LEVEL SOUTHERLY JET WILL INTENSIFY
OVER THE AREA OVERNIGHT...WITH BREEZY CONDITIONS AT TIMES IN THE
USUAL AREAS FROM NORTHEAST WY THROUGH SOUTHWEST INTO SOUTH CENTRAL
SD. ATMOSPHERE LOOKS TOO DRY TO GET ANY SHOWERS TO DEVELOP WITH THE
JET.

SUNDAY WILL SEE MOSTLY SUNNY TO PARTLY CLOUDY SKIES WITH HIGHS IN
THE 90S TO AROUND 100 DEGREES ON THE PLAINS AS THE THERMAL RIDGE
MOVES ACROSS WESTERN INTO CENTRAL SD DURING THE DAY. EXACT TIMING OF
THE COLD FRONT IS STILL A BIT UNCERTAIN...BUT IT SHOULD MOVE INTO
NORTHEAST WY LATE IN THE DAY AND ACROSS THE REST OF THE FORECAST
AREA SUNDAY NIGHT. WINDS WILL SWITCH TO THE WEST-NORTHWEST AND
BECOME BREEZY TO WINDY ACROSS NORTHWEST INTO WEST CENTRAL SD
OVERNIGHT. EMBEDDED ENERGY IN SOUTHWEST FLOW ALOFT WILL COMBINE WITH
THE FRONT TO PRODUCE AT LEAST ISOLATED SHOWERS AND STORMS OVER A
GOOD PORTION OF THE CWA SUNDAY NIGHT. THE THREAT FOR STRONG TO
SEVERE STORMS IS MINIMAL WITH THE TIMING OF THE FRONT...THOUGH WINDS
COULD GET GUSTY WITH SOME OF THE SHOWERS BEHIND THE FRONT.

.LONG TERM...MONDAY THROUGH SATURDAY
ISSUED AT 258 PM MDT SAT AUG 29 2015

NEGATIVE HEIGHT ANOMALY OVER THE PAC NW WILL REMAIN NEARLY
STATIONARY THROUGH THE PERIOD...WITH GENERALLY WARM CONDS OVER THE
NORTHERN PLAINS AS UPPER LEVEL SW FLOW PERSISTS. THE WESTERN NOAM
UPPER TROUGH WILL GRADUALLY SHIFT EAST AS A STRONGER NORTHERN
STREAM IMPULSE MERGES WITH IT...LEADING TOWARD BREAKDOWN OF THE
PERSISTENT RIDGE. IN THE MEANTIME...ABOVE NORMAL TEMPS WILL
PERSIST THROUGH MOST OF THE PERIOD...WITH MAINLY DRY CONDS. WEAK
COLD FRONT WILL ADVECT THROUGH THE AREA MONDAY MORNING...
SUPPORTING COOLER BUT STILL SEASONAL TEMPS IN A CAA REGIME MONDAY.
CENTRAL NOAM RIDGE WILL RE-SURGE TUE-THUR...WITH VERY WARM CONDS
EXPECTED ONCE AGAIN AS SOUTHERLY FLOW SPREADS OVER THE REGION.
WEAK SW FLOW IMPULSES COULD SUPPORT A FEW ISOLD SHRA/TS IN THE
TUE-WED PERIOD...ESP WITH ANY CONCENTRATED POS THETA-E ADV.
HOWEVER...LACK OF ANY APPRECIABLE SIGNALS PRECLUDE ANY POP
MENTION. NW PAC UPPER TROUGH WILL BIAS EAST BY THE END OF THE WEEK
WITH COOLER WEATHER LOOKING MORE LIKELY WITH INCREASING CHANCES
FOR RAIN.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1124 PM MDT SAT AUG 29 2015

VFR CONDITIONS WILL PREVAIL THROUGH SUNDAY AFTERNOON. LOW LEVEL
WIND SHEAR IS EXPECTED ON THE SD PLAINS THROUGH SUNDAY MORNING AS
A LOW LEVEL JET FROM 30-40KTS OCCURS. ISOLATED -TSRA POSSIBLE
OVER THE FAR WEST LATE SUNDAY AFTERNOON/EVENING.

&&

.FIRE WEATHER...
ISSUED AT 258 PM MDT SAT AUG 29 2015

WARM AND DRY CONDS WILL PERSIST ACROSS NE WY. RELATIVE HUMIDITY
ACROSS PORTIONS OF THE NORTHEAST WYOMING PLAINS WILL DROP TO 15
PERCENT OR BELOW THIS AFTERNOON AND AGAIN SUNDAY AFTERNOON. GUSTY
SOUTHWEST WINDS WILL CONTINUE THROUGH SUNDAY...AND ARE EXPECTED TO
BE STRONGEST SUNDAY AFTERNOON AHEAD OF A COLD FRONT. SW WINDS OF
20 TO 30 MPH WITH GUSTS TO AROUND 35 MPH ARE EXPECTED SUN.
PARTIALLY MIXED CONDS CAN BE EXPECTED TONIGHT GIVEN PRESSURE
FALLS...WITH SW WINDS CONTINUING UNDER POOR RH RECOVERY. WENT
AHEAD AND EXTENDED THE RED FLAG WARNING THROUGH SUNDAY AFTERNOON
FOR THIS.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
WY...RED FLAG WARNING UNTIL 8 PM MDT SUNDAY FOR WYZ259-297-298.

&&

$$

SHORT TERM...26
LONG TERM...JC
AVIATION...HELGESON
FIRE WEATHER...JC



000
FXUS63 KUNR 300525
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
1125 PM MDT SAT AUG 29 2015

.SHORT TERM...THIS EVENING THROUGH SUNDAY NIGHT
ISSUED AT 258 PM MDT SAT AUG 29 2015

CURRENT SURFACE ANALYSIS SHOWS LOW PRESSURE OVER SK...WITH A COLD
FRONT TRAILING SOUTHWESTWARD INTO NORTHWEST MT AND NORTHERN ID. A
SURFACE TROF EXTENDS SOUTHWARD ACROSS EASTERN MT INTO NORTHEAST
WY. UPPER LEVEL ANALYSIS SHOWS RIDGING OVER THE ROCKIES AND INTO
THE HIGH PLAINS. FLOW ALOFT HAS BECOME WESTERLY OVER THE AREA AND
WILL BECOME SOUTHWESTERLY INTO TONIGHT. TEMPS ARE IN THE 90S
ACROSS THE PLAINS...WITH 80S IN THE BLACK HILLS. WINDS ARE SOUTH
TO SOUTHWEST...BREEZY ACROSS PORTIONS OF NORTHEAST WY. HAZY
SUNSHINE CONTINUES THROUGH THE SMOKE...THOUGH CONDITIONS APPEAR TO
BE GRADUALLY IMPROVING IN MOST AREAS THIS AFTERNOON.

AS RIDGE BUILDS OVER AND EAST OF THE AREA THROUGH THE WEEKEND...HOT
CONDITIONS CAN BE EXPECTED. THE COLD FRONT TO THE NORTHWEST OF THE
REGION WILL EVENTUALLY MAKE IT INTO THE FORECAST AREA LATE SUNDAY
AND SUNDAY NIGHT...BRINGING MOSTLY ISOLATED SHOWERS AND
THUNDERSTORMS...ALONG WITH COOLER AND BREEZY CONDITIONS BEHIND IT
INTO MONDAY.

FOR TONIGHT...SKIES WILL STAY MAINLY CLEAR WITH LOWS MOSTLY IN THE
60S TO AROUND 70 DEGREES. LOW LEVEL SOUTHERLY JET WILL INTENSIFY
OVER THE AREA OVERNIGHT...WITH BREEZY CONDITIONS AT TIMES IN THE
USUAL AREAS FROM NORTHEAST WY THROUGH SOUTHWEST INTO SOUTH CENTRAL
SD. ATMOSPHERE LOOKS TOO DRY TO GET ANY SHOWERS TO DEVELOP WITH THE
JET.

SUNDAY WILL SEE MOSTLY SUNNY TO PARTLY CLOUDY SKIES WITH HIGHS IN
THE 90S TO AROUND 100 DEGREES ON THE PLAINS AS THE THERMAL RIDGE
MOVES ACROSS WESTERN INTO CENTRAL SD DURING THE DAY. EXACT TIMING OF
THE COLD FRONT IS STILL A BIT UNCERTAIN...BUT IT SHOULD MOVE INTO
NORTHEAST WY LATE IN THE DAY AND ACROSS THE REST OF THE FORECAST
AREA SUNDAY NIGHT. WINDS WILL SWITCH TO THE WEST-NORTHWEST AND
BECOME BREEZY TO WINDY ACROSS NORTHWEST INTO WEST CENTRAL SD
OVERNIGHT. EMBEDDED ENERGY IN SOUTHWEST FLOW ALOFT WILL COMBINE WITH
THE FRONT TO PRODUCE AT LEAST ISOLATED SHOWERS AND STORMS OVER A
GOOD PORTION OF THE CWA SUNDAY NIGHT. THE THREAT FOR STRONG TO
SEVERE STORMS IS MINIMAL WITH THE TIMING OF THE FRONT...THOUGH WINDS
COULD GET GUSTY WITH SOME OF THE SHOWERS BEHIND THE FRONT.

.LONG TERM...MONDAY THROUGH SATURDAY
ISSUED AT 258 PM MDT SAT AUG 29 2015

NEGATIVE HEIGHT ANOMALY OVER THE PAC NW WILL REMAIN NEARLY
STATIONARY THROUGH THE PERIOD...WITH GENERALLY WARM CONDS OVER THE
NORTHERN PLAINS AS UPPER LEVEL SW FLOW PERSISTS. THE WESTERN NOAM
UPPER TROUGH WILL GRADUALLY SHIFT EAST AS A STRONGER NORTHERN
STREAM IMPULSE MERGES WITH IT...LEADING TOWARD BREAKDOWN OF THE
PERSISTENT RIDGE. IN THE MEANTIME...ABOVE NORMAL TEMPS WILL
PERSIST THROUGH MOST OF THE PERIOD...WITH MAINLY DRY CONDS. WEAK
COLD FRONT WILL ADVECT THROUGH THE AREA MONDAY MORNING...
SUPPORTING COOLER BUT STILL SEASONAL TEMPS IN A CAA REGIME MONDAY.
CENTRAL NOAM RIDGE WILL RE-SURGE TUE-THUR...WITH VERY WARM CONDS
EXPECTED ONCE AGAIN AS SOUTHERLY FLOW SPREADS OVER THE REGION.
WEAK SW FLOW IMPULSES COULD SUPPORT A FEW ISOLD SHRA/TS IN THE
TUE-WED PERIOD...ESP WITH ANY CONCENTRATED POS THETA-E ADV.
HOWEVER...LACK OF ANY APPRECIABLE SIGNALS PRECLUDE ANY POP
MENTION. NW PAC UPPER TROUGH WILL BIAS EAST BY THE END OF THE WEEK
WITH COOLER WEATHER LOOKING MORE LIKELY WITH INCREASING CHANCES
FOR RAIN.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1124 PM MDT SAT AUG 29 2015

VFR CONDITIONS WILL PREVAIL THROUGH SUNDAY AFTERNOON. LOW LEVEL
WIND SHEAR IS EXPECTED ON THE SD PLAINS THROUGH SUNDAY MORNING AS
A LOW LEVEL JET FROM 30-40KTS OCCURS. ISOLATED -TSRA POSSIBLE
OVER THE FAR WEST LATE SUNDAY AFTERNOON/EVENING.

&&

.FIRE WEATHER...
ISSUED AT 258 PM MDT SAT AUG 29 2015

WARM AND DRY CONDS WILL PERSIST ACROSS NE WY. RELATIVE HUMIDITY
ACROSS PORTIONS OF THE NORTHEAST WYOMING PLAINS WILL DROP TO 15
PERCENT OR BELOW THIS AFTERNOON AND AGAIN SUNDAY AFTERNOON. GUSTY
SOUTHWEST WINDS WILL CONTINUE THROUGH SUNDAY...AND ARE EXPECTED TO
BE STRONGEST SUNDAY AFTERNOON AHEAD OF A COLD FRONT. SW WINDS OF
20 TO 30 MPH WITH GUSTS TO AROUND 35 MPH ARE EXPECTED SUN.
PARTIALLY MIXED CONDS CAN BE EXPECTED TONIGHT GIVEN PRESSURE
FALLS...WITH SW WINDS CONTINUING UNDER POOR RH RECOVERY. WENT
AHEAD AND EXTENDED THE RED FLAG WARNING THROUGH SUNDAY AFTERNOON
FOR THIS.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
WY...RED FLAG WARNING UNTIL 8 PM MDT SUNDAY FOR WYZ259-297-298.

&&

$$

SHORT TERM...26
LONG TERM...JC
AVIATION...HELGESON
FIRE WEATHER...JC



000
FXUS63 KUNR 300525
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
1125 PM MDT SAT AUG 29 2015

.SHORT TERM...THIS EVENING THROUGH SUNDAY NIGHT
ISSUED AT 258 PM MDT SAT AUG 29 2015

CURRENT SURFACE ANALYSIS SHOWS LOW PRESSURE OVER SK...WITH A COLD
FRONT TRAILING SOUTHWESTWARD INTO NORTHWEST MT AND NORTHERN ID. A
SURFACE TROF EXTENDS SOUTHWARD ACROSS EASTERN MT INTO NORTHEAST
WY. UPPER LEVEL ANALYSIS SHOWS RIDGING OVER THE ROCKIES AND INTO
THE HIGH PLAINS. FLOW ALOFT HAS BECOME WESTERLY OVER THE AREA AND
WILL BECOME SOUTHWESTERLY INTO TONIGHT. TEMPS ARE IN THE 90S
ACROSS THE PLAINS...WITH 80S IN THE BLACK HILLS. WINDS ARE SOUTH
TO SOUTHWEST...BREEZY ACROSS PORTIONS OF NORTHEAST WY. HAZY
SUNSHINE CONTINUES THROUGH THE SMOKE...THOUGH CONDITIONS APPEAR TO
BE GRADUALLY IMPROVING IN MOST AREAS THIS AFTERNOON.

AS RIDGE BUILDS OVER AND EAST OF THE AREA THROUGH THE WEEKEND...HOT
CONDITIONS CAN BE EXPECTED. THE COLD FRONT TO THE NORTHWEST OF THE
REGION WILL EVENTUALLY MAKE IT INTO THE FORECAST AREA LATE SUNDAY
AND SUNDAY NIGHT...BRINGING MOSTLY ISOLATED SHOWERS AND
THUNDERSTORMS...ALONG WITH COOLER AND BREEZY CONDITIONS BEHIND IT
INTO MONDAY.

FOR TONIGHT...SKIES WILL STAY MAINLY CLEAR WITH LOWS MOSTLY IN THE
60S TO AROUND 70 DEGREES. LOW LEVEL SOUTHERLY JET WILL INTENSIFY
OVER THE AREA OVERNIGHT...WITH BREEZY CONDITIONS AT TIMES IN THE
USUAL AREAS FROM NORTHEAST WY THROUGH SOUTHWEST INTO SOUTH CENTRAL
SD. ATMOSPHERE LOOKS TOO DRY TO GET ANY SHOWERS TO DEVELOP WITH THE
JET.

SUNDAY WILL SEE MOSTLY SUNNY TO PARTLY CLOUDY SKIES WITH HIGHS IN
THE 90S TO AROUND 100 DEGREES ON THE PLAINS AS THE THERMAL RIDGE
MOVES ACROSS WESTERN INTO CENTRAL SD DURING THE DAY. EXACT TIMING OF
THE COLD FRONT IS STILL A BIT UNCERTAIN...BUT IT SHOULD MOVE INTO
NORTHEAST WY LATE IN THE DAY AND ACROSS THE REST OF THE FORECAST
AREA SUNDAY NIGHT. WINDS WILL SWITCH TO THE WEST-NORTHWEST AND
BECOME BREEZY TO WINDY ACROSS NORTHWEST INTO WEST CENTRAL SD
OVERNIGHT. EMBEDDED ENERGY IN SOUTHWEST FLOW ALOFT WILL COMBINE WITH
THE FRONT TO PRODUCE AT LEAST ISOLATED SHOWERS AND STORMS OVER A
GOOD PORTION OF THE CWA SUNDAY NIGHT. THE THREAT FOR STRONG TO
SEVERE STORMS IS MINIMAL WITH THE TIMING OF THE FRONT...THOUGH WINDS
COULD GET GUSTY WITH SOME OF THE SHOWERS BEHIND THE FRONT.

.LONG TERM...MONDAY THROUGH SATURDAY
ISSUED AT 258 PM MDT SAT AUG 29 2015

NEGATIVE HEIGHT ANOMALY OVER THE PAC NW WILL REMAIN NEARLY
STATIONARY THROUGH THE PERIOD...WITH GENERALLY WARM CONDS OVER THE
NORTHERN PLAINS AS UPPER LEVEL SW FLOW PERSISTS. THE WESTERN NOAM
UPPER TROUGH WILL GRADUALLY SHIFT EAST AS A STRONGER NORTHERN
STREAM IMPULSE MERGES WITH IT...LEADING TOWARD BREAKDOWN OF THE
PERSISTENT RIDGE. IN THE MEANTIME...ABOVE NORMAL TEMPS WILL
PERSIST THROUGH MOST OF THE PERIOD...WITH MAINLY DRY CONDS. WEAK
COLD FRONT WILL ADVECT THROUGH THE AREA MONDAY MORNING...
SUPPORTING COOLER BUT STILL SEASONAL TEMPS IN A CAA REGIME MONDAY.
CENTRAL NOAM RIDGE WILL RE-SURGE TUE-THUR...WITH VERY WARM CONDS
EXPECTED ONCE AGAIN AS SOUTHERLY FLOW SPREADS OVER THE REGION.
WEAK SW FLOW IMPULSES COULD SUPPORT A FEW ISOLD SHRA/TS IN THE
TUE-WED PERIOD...ESP WITH ANY CONCENTRATED POS THETA-E ADV.
HOWEVER...LACK OF ANY APPRECIABLE SIGNALS PRECLUDE ANY POP
MENTION. NW PAC UPPER TROUGH WILL BIAS EAST BY THE END OF THE WEEK
WITH COOLER WEATHER LOOKING MORE LIKELY WITH INCREASING CHANCES
FOR RAIN.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1124 PM MDT SAT AUG 29 2015

VFR CONDITIONS WILL PREVAIL THROUGH SUNDAY AFTERNOON. LOW LEVEL
WIND SHEAR IS EXPECTED ON THE SD PLAINS THROUGH SUNDAY MORNING AS
A LOW LEVEL JET FROM 30-40KTS OCCURS. ISOLATED -TSRA POSSIBLE
OVER THE FAR WEST LATE SUNDAY AFTERNOON/EVENING.

&&

.FIRE WEATHER...
ISSUED AT 258 PM MDT SAT AUG 29 2015

WARM AND DRY CONDS WILL PERSIST ACROSS NE WY. RELATIVE HUMIDITY
ACROSS PORTIONS OF THE NORTHEAST WYOMING PLAINS WILL DROP TO 15
PERCENT OR BELOW THIS AFTERNOON AND AGAIN SUNDAY AFTERNOON. GUSTY
SOUTHWEST WINDS WILL CONTINUE THROUGH SUNDAY...AND ARE EXPECTED TO
BE STRONGEST SUNDAY AFTERNOON AHEAD OF A COLD FRONT. SW WINDS OF
20 TO 30 MPH WITH GUSTS TO AROUND 35 MPH ARE EXPECTED SUN.
PARTIALLY MIXED CONDS CAN BE EXPECTED TONIGHT GIVEN PRESSURE
FALLS...WITH SW WINDS CONTINUING UNDER POOR RH RECOVERY. WENT
AHEAD AND EXTENDED THE RED FLAG WARNING THROUGH SUNDAY AFTERNOON
FOR THIS.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
WY...RED FLAG WARNING UNTIL 8 PM MDT SUNDAY FOR WYZ259-297-298.

&&

$$

SHORT TERM...26
LONG TERM...JC
AVIATION...HELGESON
FIRE WEATHER...JC




000
FXUS63 KUNR 300525
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
1125 PM MDT SAT AUG 29 2015

.SHORT TERM...THIS EVENING THROUGH SUNDAY NIGHT
ISSUED AT 258 PM MDT SAT AUG 29 2015

CURRENT SURFACE ANALYSIS SHOWS LOW PRESSURE OVER SK...WITH A COLD
FRONT TRAILING SOUTHWESTWARD INTO NORTHWEST MT AND NORTHERN ID. A
SURFACE TROF EXTENDS SOUTHWARD ACROSS EASTERN MT INTO NORTHEAST
WY. UPPER LEVEL ANALYSIS SHOWS RIDGING OVER THE ROCKIES AND INTO
THE HIGH PLAINS. FLOW ALOFT HAS BECOME WESTERLY OVER THE AREA AND
WILL BECOME SOUTHWESTERLY INTO TONIGHT. TEMPS ARE IN THE 90S
ACROSS THE PLAINS...WITH 80S IN THE BLACK HILLS. WINDS ARE SOUTH
TO SOUTHWEST...BREEZY ACROSS PORTIONS OF NORTHEAST WY. HAZY
SUNSHINE CONTINUES THROUGH THE SMOKE...THOUGH CONDITIONS APPEAR TO
BE GRADUALLY IMPROVING IN MOST AREAS THIS AFTERNOON.

AS RIDGE BUILDS OVER AND EAST OF THE AREA THROUGH THE WEEKEND...HOT
CONDITIONS CAN BE EXPECTED. THE COLD FRONT TO THE NORTHWEST OF THE
REGION WILL EVENTUALLY MAKE IT INTO THE FORECAST AREA LATE SUNDAY
AND SUNDAY NIGHT...BRINGING MOSTLY ISOLATED SHOWERS AND
THUNDERSTORMS...ALONG WITH COOLER AND BREEZY CONDITIONS BEHIND IT
INTO MONDAY.

FOR TONIGHT...SKIES WILL STAY MAINLY CLEAR WITH LOWS MOSTLY IN THE
60S TO AROUND 70 DEGREES. LOW LEVEL SOUTHERLY JET WILL INTENSIFY
OVER THE AREA OVERNIGHT...WITH BREEZY CONDITIONS AT TIMES IN THE
USUAL AREAS FROM NORTHEAST WY THROUGH SOUTHWEST INTO SOUTH CENTRAL
SD. ATMOSPHERE LOOKS TOO DRY TO GET ANY SHOWERS TO DEVELOP WITH THE
JET.

SUNDAY WILL SEE MOSTLY SUNNY TO PARTLY CLOUDY SKIES WITH HIGHS IN
THE 90S TO AROUND 100 DEGREES ON THE PLAINS AS THE THERMAL RIDGE
MOVES ACROSS WESTERN INTO CENTRAL SD DURING THE DAY. EXACT TIMING OF
THE COLD FRONT IS STILL A BIT UNCERTAIN...BUT IT SHOULD MOVE INTO
NORTHEAST WY LATE IN THE DAY AND ACROSS THE REST OF THE FORECAST
AREA SUNDAY NIGHT. WINDS WILL SWITCH TO THE WEST-NORTHWEST AND
BECOME BREEZY TO WINDY ACROSS NORTHWEST INTO WEST CENTRAL SD
OVERNIGHT. EMBEDDED ENERGY IN SOUTHWEST FLOW ALOFT WILL COMBINE WITH
THE FRONT TO PRODUCE AT LEAST ISOLATED SHOWERS AND STORMS OVER A
GOOD PORTION OF THE CWA SUNDAY NIGHT. THE THREAT FOR STRONG TO
SEVERE STORMS IS MINIMAL WITH THE TIMING OF THE FRONT...THOUGH WINDS
COULD GET GUSTY WITH SOME OF THE SHOWERS BEHIND THE FRONT.

.LONG TERM...MONDAY THROUGH SATURDAY
ISSUED AT 258 PM MDT SAT AUG 29 2015

NEGATIVE HEIGHT ANOMALY OVER THE PAC NW WILL REMAIN NEARLY
STATIONARY THROUGH THE PERIOD...WITH GENERALLY WARM CONDS OVER THE
NORTHERN PLAINS AS UPPER LEVEL SW FLOW PERSISTS. THE WESTERN NOAM
UPPER TROUGH WILL GRADUALLY SHIFT EAST AS A STRONGER NORTHERN
STREAM IMPULSE MERGES WITH IT...LEADING TOWARD BREAKDOWN OF THE
PERSISTENT RIDGE. IN THE MEANTIME...ABOVE NORMAL TEMPS WILL
PERSIST THROUGH MOST OF THE PERIOD...WITH MAINLY DRY CONDS. WEAK
COLD FRONT WILL ADVECT THROUGH THE AREA MONDAY MORNING...
SUPPORTING COOLER BUT STILL SEASONAL TEMPS IN A CAA REGIME MONDAY.
CENTRAL NOAM RIDGE WILL RE-SURGE TUE-THUR...WITH VERY WARM CONDS
EXPECTED ONCE AGAIN AS SOUTHERLY FLOW SPREADS OVER THE REGION.
WEAK SW FLOW IMPULSES COULD SUPPORT A FEW ISOLD SHRA/TS IN THE
TUE-WED PERIOD...ESP WITH ANY CONCENTRATED POS THETA-E ADV.
HOWEVER...LACK OF ANY APPRECIABLE SIGNALS PRECLUDE ANY POP
MENTION. NW PAC UPPER TROUGH WILL BIAS EAST BY THE END OF THE WEEK
WITH COOLER WEATHER LOOKING MORE LIKELY WITH INCREASING CHANCES
FOR RAIN.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1124 PM MDT SAT AUG 29 2015

VFR CONDITIONS WILL PREVAIL THROUGH SUNDAY AFTERNOON. LOW LEVEL
WIND SHEAR IS EXPECTED ON THE SD PLAINS THROUGH SUNDAY MORNING AS
A LOW LEVEL JET FROM 30-40KTS OCCURS. ISOLATED -TSRA POSSIBLE
OVER THE FAR WEST LATE SUNDAY AFTERNOON/EVENING.

&&

.FIRE WEATHER...
ISSUED AT 258 PM MDT SAT AUG 29 2015

WARM AND DRY CONDS WILL PERSIST ACROSS NE WY. RELATIVE HUMIDITY
ACROSS PORTIONS OF THE NORTHEAST WYOMING PLAINS WILL DROP TO 15
PERCENT OR BELOW THIS AFTERNOON AND AGAIN SUNDAY AFTERNOON. GUSTY
SOUTHWEST WINDS WILL CONTINUE THROUGH SUNDAY...AND ARE EXPECTED TO
BE STRONGEST SUNDAY AFTERNOON AHEAD OF A COLD FRONT. SW WINDS OF
20 TO 30 MPH WITH GUSTS TO AROUND 35 MPH ARE EXPECTED SUN.
PARTIALLY MIXED CONDS CAN BE EXPECTED TONIGHT GIVEN PRESSURE
FALLS...WITH SW WINDS CONTINUING UNDER POOR RH RECOVERY. WENT
AHEAD AND EXTENDED THE RED FLAG WARNING THROUGH SUNDAY AFTERNOON
FOR THIS.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
WY...RED FLAG WARNING UNTIL 8 PM MDT SUNDAY FOR WYZ259-297-298.

&&

$$

SHORT TERM...26
LONG TERM...JC
AVIATION...HELGESON
FIRE WEATHER...JC



000
FXUS65 KCYS 292330
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
530 PM MDT SAT AUG 29 2015

.SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT)
ISSUED AT 300 PM MDT SAT AUG 29 2015

FORECAST CHALLENGES DEAL WITH WINDS...PRECIPITATION CHANCES AND
POSSIBLE FIRE WEATHER CONCERNS THROUGH THE SHORT TERM.

CURRENTLY...LATEST VISIBLE SATELLITE IMAGERY FROM THIS MORNING
SHOWING ELEVATED SMOKE HANGING TOUGH OVER AREAS EAST OF THE
LARAMIE RANGE. LOW PRESSURE OFF THE COAST OF WASHINGTON STATE WITH
A FRONTAL SYSTEM BEING ANALYZED NEAR THE IDAHO/OREGON
BORDER...EXTENDING UP INTO ALBERTA CANADA. SOUTHEAST WYOMING
REMAINS UNDER AN UPPER RIDGE AXIS WITH FAIRLY LIGHT WINDS FOR THIS
PART OF THE COUNTRY.

RIDGE AXIS SHIFTS EAST THIS EVENING WITH 700MB SOUTHWESTERLY WINDS
INCREASING ACROSS CARBON AND ALBANY COUNTIES. AS HAS BEEN THE CASE
THE PAST WEEK...MODELS CONTINUE TO SHOW STRONG 850MB WINDS ACROSS
THE PANHANDLE THIS EVENING...UP TO 35-40KTS. COULD BE A LOW LEVEL
JET SETTING UP OUT THERE. FORECAST SOUNDINGS DO SHOW A LOW LEVEL
INVERSION SETTING UP THAT COULD SHELTER THE PANHANDLE FROM THESE
WINDS. BUT IF THE INVERSION DOES NOT SET UP...COULD BE DEALING
WITH ADVISORY LEVEL WINDS OUT THERE TONIGHT.

UPPER SHORTWAVE TROUGH MOVES INTO WESTERN MONTANA SUNDAY
AFTERNOON. STRONG 700MB WINDS OF 35-40KTS ACROSS CARBON AND ALBANY
COUNTIES AS WELL AS CONVERSE/NIOBRARA COUNTIES AND NORTH LARAMIE
RANGE. PRECIP DELAYED INTO THE AREA UNTIL LATE AFTERNOON...INTO
THE EVENING HOURS. DID UPGRADE THE FIRE WEATHER WATCH FOR
CONVERSE/NIOBRARA COUNTIES TO A RED FLAG WARNING THIS AFTERNOON. NIGHT
SHIFT WILL NEED TO CONSIDER NORTHERN 309 AND 310 AS WELL AS WE
SHOULD BE VERY DRY UP THERE WITH POOR OVERNIGHT HUMIDITY
RECOVERIES.

CONVECTION MOVES INTO OUR WESTERN ZONES LATE SUNDAY
AFTERNOON...PERSISTING INTO THE EVENING HOURS. GFS BY FAR THE
MOST BULLISH ON POPS OVER THE ECMWF AND NAM. DID DECREASE POPS
SOME FOR OUR EASTERN ZONES TOMORROW AFTERNOON.

LOOK FOR FRONTAL PASSAGE NEAR MIDNIGHT MONDAY MORNING WITH COOLER
AIR SPREADING INTO THE AREA FOR MONDAY.

.LONG TERM...(TUESDAY THROUGH SATURDAY)

ISSUED AT 338 PM MDT SAT AUG 29 2015

AFTER THE FRONTAL PASSAGE ON MONDAY... LINGERING MOISTURE ON
TUESDAY MAY CAUSE A FEW SHOWERS AND THUNDERSTORMS OVER THE SIERRA
MADRE AND SNOWY RANGES. GENERALLY SOUTHWESTERLY FLOW ALOFT WILL
PREVAIL FOR MOST OF THE CWA WITH AN UPPER LEVEL RIDGE BUILDING
OVERHEAD. THIS WILL BRING WARMER TEMPERATURES AND DRIER CONDITIONS
THROUGHOUT THE WEEK. WITH LACK OF ANY FORCING AND DRIER LOW LEVELS...
POP CHANCES WILL REMAIN LOW WEDNESDAY AND THURSDAY. FRIDAY THE
CHANCES FOR SHOWERS AND THUNDERSTORMS INCREASE WITH THE PASSAGE OF
AN UPPER LEVEL TROUGH... MAINLY EFFECTING EAST OF THE LARAMIE
RANGE INTO THE NEBRASKA PANHANDLE.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY AFTERNOON)
ISSUED AT 530 PM MDT SAT AUG 29 2015

VFR EXPECTED OVER ALL TERMINALS OVERALL THROUGH THE PERIOD.  SOME
MINOR REDUCTION IN VSBY EARLY THIS EVENING DUE TO SMOKE MAINLY
AFFECTING KCDR.  ISOLD SHOWERS AND TSTMS DEVELOPING AROUND THE SE WY
MTNS SUNDAY AFTERNOON.

&&

.FIRE WEATHER...
ISSUED AT 110 PM MDT SAT AUG 29 2015

INCREASING WINDS TONIGHT INTO SUNDAY AS LOW PRESSURE TRACKS INTO
MONTANA SUNDAY AFTERNOON. CHALLENGING FORECAST AS WIND SPEEDS
COULD BE OFFSET BY INCREASING CLOUDS...WHICH WOULD LIMIT MIXING.
WILL KEEP RED FLAG WARNING FOR FWZ 301 FOR SUNDAY LATE MORNING
THROUGH THE AFTERNOON. INCREASING MOISTURE SUNDAY AFTERNOON ACROSS
CARBON AND ALBANY COUNTIES WILL GIVE CHANCES FOR WETTING RAINS OUT
THAT WAY FROM MID AFTERNOON THROUGH MID EVENING. WINDY PERIOD
AHEAD AS THE LOW SLOWLY TRACKS ACROSS MONTANA.
&&

.CYS WATCHES/WARNINGS/ADVISORIES...

WY...RED FLAG WARNING FROM 11 AM TO 7 PM MDT SUNDAY FOR WYZ301.

NE...NONE.

&&

$$

SHORT TERM...GCC
LONG TERM...SML/KC
AVIATION...SML/KC
FIRE WEATHER...GCC



000
FXUS65 KCYS 292330
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
530 PM MDT SAT AUG 29 2015

.SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT)
ISSUED AT 300 PM MDT SAT AUG 29 2015

FORECAST CHALLENGES DEAL WITH WINDS...PRECIPITATION CHANCES AND
POSSIBLE FIRE WEATHER CONCERNS THROUGH THE SHORT TERM.

CURRENTLY...LATEST VISIBLE SATELLITE IMAGERY FROM THIS MORNING
SHOWING ELEVATED SMOKE HANGING TOUGH OVER AREAS EAST OF THE
LARAMIE RANGE. LOW PRESSURE OFF THE COAST OF WASHINGTON STATE WITH
A FRONTAL SYSTEM BEING ANALYZED NEAR THE IDAHO/OREGON
BORDER...EXTENDING UP INTO ALBERTA CANADA. SOUTHEAST WYOMING
REMAINS UNDER AN UPPER RIDGE AXIS WITH FAIRLY LIGHT WINDS FOR THIS
PART OF THE COUNTRY.

RIDGE AXIS SHIFTS EAST THIS EVENING WITH 700MB SOUTHWESTERLY WINDS
INCREASING ACROSS CARBON AND ALBANY COUNTIES. AS HAS BEEN THE CASE
THE PAST WEEK...MODELS CONTINUE TO SHOW STRONG 850MB WINDS ACROSS
THE PANHANDLE THIS EVENING...UP TO 35-40KTS. COULD BE A LOW LEVEL
JET SETTING UP OUT THERE. FORECAST SOUNDINGS DO SHOW A LOW LEVEL
INVERSION SETTING UP THAT COULD SHELTER THE PANHANDLE FROM THESE
WINDS. BUT IF THE INVERSION DOES NOT SET UP...COULD BE DEALING
WITH ADVISORY LEVEL WINDS OUT THERE TONIGHT.

UPPER SHORTWAVE TROUGH MOVES INTO WESTERN MONTANA SUNDAY
AFTERNOON. STRONG 700MB WINDS OF 35-40KTS ACROSS CARBON AND ALBANY
COUNTIES AS WELL AS CONVERSE/NIOBRARA COUNTIES AND NORTH LARAMIE
RANGE. PRECIP DELAYED INTO THE AREA UNTIL LATE AFTERNOON...INTO
THE EVENING HOURS. DID UPGRADE THE FIRE WEATHER WATCH FOR
CONVERSE/NIOBRARA COUNTIES TO A RED FLAG WARNING THIS AFTERNOON. NIGHT
SHIFT WILL NEED TO CONSIDER NORTHERN 309 AND 310 AS WELL AS WE
SHOULD BE VERY DRY UP THERE WITH POOR OVERNIGHT HUMIDITY
RECOVERIES.

CONVECTION MOVES INTO OUR WESTERN ZONES LATE SUNDAY
AFTERNOON...PERSISTING INTO THE EVENING HOURS. GFS BY FAR THE
MOST BULLISH ON POPS OVER THE ECMWF AND NAM. DID DECREASE POPS
SOME FOR OUR EASTERN ZONES TOMORROW AFTERNOON.

LOOK FOR FRONTAL PASSAGE NEAR MIDNIGHT MONDAY MORNING WITH COOLER
AIR SPREADING INTO THE AREA FOR MONDAY.

.LONG TERM...(TUESDAY THROUGH SATURDAY)

ISSUED AT 338 PM MDT SAT AUG 29 2015

AFTER THE FRONTAL PASSAGE ON MONDAY... LINGERING MOISTURE ON
TUESDAY MAY CAUSE A FEW SHOWERS AND THUNDERSTORMS OVER THE SIERRA
MADRE AND SNOWY RANGES. GENERALLY SOUTHWESTERLY FLOW ALOFT WILL
PREVAIL FOR MOST OF THE CWA WITH AN UPPER LEVEL RIDGE BUILDING
OVERHEAD. THIS WILL BRING WARMER TEMPERATURES AND DRIER CONDITIONS
THROUGHOUT THE WEEK. WITH LACK OF ANY FORCING AND DRIER LOW LEVELS...
POP CHANCES WILL REMAIN LOW WEDNESDAY AND THURSDAY. FRIDAY THE
CHANCES FOR SHOWERS AND THUNDERSTORMS INCREASE WITH THE PASSAGE OF
AN UPPER LEVEL TROUGH... MAINLY EFFECTING EAST OF THE LARAMIE
RANGE INTO THE NEBRASKA PANHANDLE.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY AFTERNOON)
ISSUED AT 530 PM MDT SAT AUG 29 2015

VFR EXPECTED OVER ALL TERMINALS OVERALL THROUGH THE PERIOD.  SOME
MINOR REDUCTION IN VSBY EARLY THIS EVENING DUE TO SMOKE MAINLY
AFFECTING KCDR.  ISOLD SHOWERS AND TSTMS DEVELOPING AROUND THE SE WY
MTNS SUNDAY AFTERNOON.

&&

.FIRE WEATHER...
ISSUED AT 110 PM MDT SAT AUG 29 2015

INCREASING WINDS TONIGHT INTO SUNDAY AS LOW PRESSURE TRACKS INTO
MONTANA SUNDAY AFTERNOON. CHALLENGING FORECAST AS WIND SPEEDS
COULD BE OFFSET BY INCREASING CLOUDS...WHICH WOULD LIMIT MIXING.
WILL KEEP RED FLAG WARNING FOR FWZ 301 FOR SUNDAY LATE MORNING
THROUGH THE AFTERNOON. INCREASING MOISTURE SUNDAY AFTERNOON ACROSS
CARBON AND ALBANY COUNTIES WILL GIVE CHANCES FOR WETTING RAINS OUT
THAT WAY FROM MID AFTERNOON THROUGH MID EVENING. WINDY PERIOD
AHEAD AS THE LOW SLOWLY TRACKS ACROSS MONTANA.
&&

.CYS WATCHES/WARNINGS/ADVISORIES...

WY...RED FLAG WARNING FROM 11 AM TO 7 PM MDT SUNDAY FOR WYZ301.

NE...NONE.

&&

$$

SHORT TERM...GCC
LONG TERM...SML/KC
AVIATION...SML/KC
FIRE WEATHER...GCC




000
FXUS65 KCYS 292330
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
530 PM MDT SAT AUG 29 2015

.SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT)
ISSUED AT 300 PM MDT SAT AUG 29 2015

FORECAST CHALLENGES DEAL WITH WINDS...PRECIPITATION CHANCES AND
POSSIBLE FIRE WEATHER CONCERNS THROUGH THE SHORT TERM.

CURRENTLY...LATEST VISIBLE SATELLITE IMAGERY FROM THIS MORNING
SHOWING ELEVATED SMOKE HANGING TOUGH OVER AREAS EAST OF THE
LARAMIE RANGE. LOW PRESSURE OFF THE COAST OF WASHINGTON STATE WITH
A FRONTAL SYSTEM BEING ANALYZED NEAR THE IDAHO/OREGON
BORDER...EXTENDING UP INTO ALBERTA CANADA. SOUTHEAST WYOMING
REMAINS UNDER AN UPPER RIDGE AXIS WITH FAIRLY LIGHT WINDS FOR THIS
PART OF THE COUNTRY.

RIDGE AXIS SHIFTS EAST THIS EVENING WITH 700MB SOUTHWESTERLY WINDS
INCREASING ACROSS CARBON AND ALBANY COUNTIES. AS HAS BEEN THE CASE
THE PAST WEEK...MODELS CONTINUE TO SHOW STRONG 850MB WINDS ACROSS
THE PANHANDLE THIS EVENING...UP TO 35-40KTS. COULD BE A LOW LEVEL
JET SETTING UP OUT THERE. FORECAST SOUNDINGS DO SHOW A LOW LEVEL
INVERSION SETTING UP THAT COULD SHELTER THE PANHANDLE FROM THESE
WINDS. BUT IF THE INVERSION DOES NOT SET UP...COULD BE DEALING
WITH ADVISORY LEVEL WINDS OUT THERE TONIGHT.

UPPER SHORTWAVE TROUGH MOVES INTO WESTERN MONTANA SUNDAY
AFTERNOON. STRONG 700MB WINDS OF 35-40KTS ACROSS CARBON AND ALBANY
COUNTIES AS WELL AS CONVERSE/NIOBRARA COUNTIES AND NORTH LARAMIE
RANGE. PRECIP DELAYED INTO THE AREA UNTIL LATE AFTERNOON...INTO
THE EVENING HOURS. DID UPGRADE THE FIRE WEATHER WATCH FOR
CONVERSE/NIOBRARA COUNTIES TO A RED FLAG WARNING THIS AFTERNOON. NIGHT
SHIFT WILL NEED TO CONSIDER NORTHERN 309 AND 310 AS WELL AS WE
SHOULD BE VERY DRY UP THERE WITH POOR OVERNIGHT HUMIDITY
RECOVERIES.

CONVECTION MOVES INTO OUR WESTERN ZONES LATE SUNDAY
AFTERNOON...PERSISTING INTO THE EVENING HOURS. GFS BY FAR THE
MOST BULLISH ON POPS OVER THE ECMWF AND NAM. DID DECREASE POPS
SOME FOR OUR EASTERN ZONES TOMORROW AFTERNOON.

LOOK FOR FRONTAL PASSAGE NEAR MIDNIGHT MONDAY MORNING WITH COOLER
AIR SPREADING INTO THE AREA FOR MONDAY.

.LONG TERM...(TUESDAY THROUGH SATURDAY)

ISSUED AT 338 PM MDT SAT AUG 29 2015

AFTER THE FRONTAL PASSAGE ON MONDAY... LINGERING MOISTURE ON
TUESDAY MAY CAUSE A FEW SHOWERS AND THUNDERSTORMS OVER THE SIERRA
MADRE AND SNOWY RANGES. GENERALLY SOUTHWESTERLY FLOW ALOFT WILL
PREVAIL FOR MOST OF THE CWA WITH AN UPPER LEVEL RIDGE BUILDING
OVERHEAD. THIS WILL BRING WARMER TEMPERATURES AND DRIER CONDITIONS
THROUGHOUT THE WEEK. WITH LACK OF ANY FORCING AND DRIER LOW LEVELS...
POP CHANCES WILL REMAIN LOW WEDNESDAY AND THURSDAY. FRIDAY THE
CHANCES FOR SHOWERS AND THUNDERSTORMS INCREASE WITH THE PASSAGE OF
AN UPPER LEVEL TROUGH... MAINLY EFFECTING EAST OF THE LARAMIE
RANGE INTO THE NEBRASKA PANHANDLE.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY AFTERNOON)
ISSUED AT 530 PM MDT SAT AUG 29 2015

VFR EXPECTED OVER ALL TERMINALS OVERALL THROUGH THE PERIOD.  SOME
MINOR REDUCTION IN VSBY EARLY THIS EVENING DUE TO SMOKE MAINLY
AFFECTING KCDR.  ISOLD SHOWERS AND TSTMS DEVELOPING AROUND THE SE WY
MTNS SUNDAY AFTERNOON.

&&

.FIRE WEATHER...
ISSUED AT 110 PM MDT SAT AUG 29 2015

INCREASING WINDS TONIGHT INTO SUNDAY AS LOW PRESSURE TRACKS INTO
MONTANA SUNDAY AFTERNOON. CHALLENGING FORECAST AS WIND SPEEDS
COULD BE OFFSET BY INCREASING CLOUDS...WHICH WOULD LIMIT MIXING.
WILL KEEP RED FLAG WARNING FOR FWZ 301 FOR SUNDAY LATE MORNING
THROUGH THE AFTERNOON. INCREASING MOISTURE SUNDAY AFTERNOON ACROSS
CARBON AND ALBANY COUNTIES WILL GIVE CHANCES FOR WETTING RAINS OUT
THAT WAY FROM MID AFTERNOON THROUGH MID EVENING. WINDY PERIOD
AHEAD AS THE LOW SLOWLY TRACKS ACROSS MONTANA.
&&

.CYS WATCHES/WARNINGS/ADVISORIES...

WY...RED FLAG WARNING FROM 11 AM TO 7 PM MDT SUNDAY FOR WYZ301.

NE...NONE.

&&

$$

SHORT TERM...GCC
LONG TERM...SML/KC
AVIATION...SML/KC
FIRE WEATHER...GCC




000
FXUS65 KCYS 292330
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
530 PM MDT SAT AUG 29 2015

.SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT)
ISSUED AT 300 PM MDT SAT AUG 29 2015

FORECAST CHALLENGES DEAL WITH WINDS...PRECIPITATION CHANCES AND
POSSIBLE FIRE WEATHER CONCERNS THROUGH THE SHORT TERM.

CURRENTLY...LATEST VISIBLE SATELLITE IMAGERY FROM THIS MORNING
SHOWING ELEVATED SMOKE HANGING TOUGH OVER AREAS EAST OF THE
LARAMIE RANGE. LOW PRESSURE OFF THE COAST OF WASHINGTON STATE WITH
A FRONTAL SYSTEM BEING ANALYZED NEAR THE IDAHO/OREGON
BORDER...EXTENDING UP INTO ALBERTA CANADA. SOUTHEAST WYOMING
REMAINS UNDER AN UPPER RIDGE AXIS WITH FAIRLY LIGHT WINDS FOR THIS
PART OF THE COUNTRY.

RIDGE AXIS SHIFTS EAST THIS EVENING WITH 700MB SOUTHWESTERLY WINDS
INCREASING ACROSS CARBON AND ALBANY COUNTIES. AS HAS BEEN THE CASE
THE PAST WEEK...MODELS CONTINUE TO SHOW STRONG 850MB WINDS ACROSS
THE PANHANDLE THIS EVENING...UP TO 35-40KTS. COULD BE A LOW LEVEL
JET SETTING UP OUT THERE. FORECAST SOUNDINGS DO SHOW A LOW LEVEL
INVERSION SETTING UP THAT COULD SHELTER THE PANHANDLE FROM THESE
WINDS. BUT IF THE INVERSION DOES NOT SET UP...COULD BE DEALING
WITH ADVISORY LEVEL WINDS OUT THERE TONIGHT.

UPPER SHORTWAVE TROUGH MOVES INTO WESTERN MONTANA SUNDAY
AFTERNOON. STRONG 700MB WINDS OF 35-40KTS ACROSS CARBON AND ALBANY
COUNTIES AS WELL AS CONVERSE/NIOBRARA COUNTIES AND NORTH LARAMIE
RANGE. PRECIP DELAYED INTO THE AREA UNTIL LATE AFTERNOON...INTO
THE EVENING HOURS. DID UPGRADE THE FIRE WEATHER WATCH FOR
CONVERSE/NIOBRARA COUNTIES TO A RED FLAG WARNING THIS AFTERNOON. NIGHT
SHIFT WILL NEED TO CONSIDER NORTHERN 309 AND 310 AS WELL AS WE
SHOULD BE VERY DRY UP THERE WITH POOR OVERNIGHT HUMIDITY
RECOVERIES.

CONVECTION MOVES INTO OUR WESTERN ZONES LATE SUNDAY
AFTERNOON...PERSISTING INTO THE EVENING HOURS. GFS BY FAR THE
MOST BULLISH ON POPS OVER THE ECMWF AND NAM. DID DECREASE POPS
SOME FOR OUR EASTERN ZONES TOMORROW AFTERNOON.

LOOK FOR FRONTAL PASSAGE NEAR MIDNIGHT MONDAY MORNING WITH COOLER
AIR SPREADING INTO THE AREA FOR MONDAY.

.LONG TERM...(TUESDAY THROUGH SATURDAY)

ISSUED AT 338 PM MDT SAT AUG 29 2015

AFTER THE FRONTAL PASSAGE ON MONDAY... LINGERING MOISTURE ON
TUESDAY MAY CAUSE A FEW SHOWERS AND THUNDERSTORMS OVER THE SIERRA
MADRE AND SNOWY RANGES. GENERALLY SOUTHWESTERLY FLOW ALOFT WILL
PREVAIL FOR MOST OF THE CWA WITH AN UPPER LEVEL RIDGE BUILDING
OVERHEAD. THIS WILL BRING WARMER TEMPERATURES AND DRIER CONDITIONS
THROUGHOUT THE WEEK. WITH LACK OF ANY FORCING AND DRIER LOW LEVELS...
POP CHANCES WILL REMAIN LOW WEDNESDAY AND THURSDAY. FRIDAY THE
CHANCES FOR SHOWERS AND THUNDERSTORMS INCREASE WITH THE PASSAGE OF
AN UPPER LEVEL TROUGH... MAINLY EFFECTING EAST OF THE LARAMIE
RANGE INTO THE NEBRASKA PANHANDLE.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY AFTERNOON)
ISSUED AT 530 PM MDT SAT AUG 29 2015

VFR EXPECTED OVER ALL TERMINALS OVERALL THROUGH THE PERIOD.  SOME
MINOR REDUCTION IN VSBY EARLY THIS EVENING DUE TO SMOKE MAINLY
AFFECTING KCDR.  ISOLD SHOWERS AND TSTMS DEVELOPING AROUND THE SE WY
MTNS SUNDAY AFTERNOON.

&&

.FIRE WEATHER...
ISSUED AT 110 PM MDT SAT AUG 29 2015

INCREASING WINDS TONIGHT INTO SUNDAY AS LOW PRESSURE TRACKS INTO
MONTANA SUNDAY AFTERNOON. CHALLENGING FORECAST AS WIND SPEEDS
COULD BE OFFSET BY INCREASING CLOUDS...WHICH WOULD LIMIT MIXING.
WILL KEEP RED FLAG WARNING FOR FWZ 301 FOR SUNDAY LATE MORNING
THROUGH THE AFTERNOON. INCREASING MOISTURE SUNDAY AFTERNOON ACROSS
CARBON AND ALBANY COUNTIES WILL GIVE CHANCES FOR WETTING RAINS OUT
THAT WAY FROM MID AFTERNOON THROUGH MID EVENING. WINDY PERIOD
AHEAD AS THE LOW SLOWLY TRACKS ACROSS MONTANA.
&&

.CYS WATCHES/WARNINGS/ADVISORIES...

WY...RED FLAG WARNING FROM 11 AM TO 7 PM MDT SUNDAY FOR WYZ301.

NE...NONE.

&&

$$

SHORT TERM...GCC
LONG TERM...SML/KC
AVIATION...SML/KC
FIRE WEATHER...GCC



000
FXUS63 KUNR 292316
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
516 PM MDT SAT AUG 29 2015

.SHORT TERM...THIS EVENING THROUGH SUNDAY NIGHT
ISSUED AT 258 PM MDT SAT AUG 29 2015

CURRENT SURFACE ANALYSIS SHOWS LOW PRESSURE OVER SK...WITH A COLD
FRONT TRAILING SOUTHWESTWARD INTO NORTHWEST MT AND NORTHERN ID. A
SURFACE TROF EXTENDS SOUTHWARD ACROSS EASTERN MT INTO NORTHEAST
WY. UPPER LEVEL ANALYSIS SHOWS RIDGING OVER THE ROCKIES AND INTO
THE HIGH PLAINS. FLOW ALOFT HAS BECOME WESTERLY OVER THE AREA AND
WILL BECOME SOUTHWESTERLY INTO TONIGHT. TEMPS ARE IN THE 90S
ACROSS THE PLAINS...WITH 80S IN THE BLACK HILLS. WINDS ARE SOUTH
TO SOUTHWEST...BREEZY ACROSS PORTIONS OF NORTHEAST WY. HAZY
SUNSHINE CONTINUES THROUGH THE SMOKE...THOUGH CONDITIONS APPEAR TO
BE GRADUALLY IMPROVING IN MOST AREAS THIS AFTERNOON.

AS RIDGE BUILDS OVER AND EAST OF THE AREA THROUGH THE WEEKEND...HOT
CONDITIONS CAN BE EXPECTED. THE COLD FRONT TO THE NORTHWEST OF THE
REGION WILL EVENTUALLY MAKE IT INTO THE FORECAST AREA LATE SUNDAY
AND SUNDAY NIGHT...BRINGING MOSTLY ISOLATED SHOWERS AND
THUNDERSTORMS...ALONG WITH COOLER AND BREEZY CONDITIONS BEHIND IT
INTO MONDAY.

FOR TONIGHT...SKIES WILL STAY MAINLY CLEAR WITH LOWS MOSTLY IN THE
60S TO AROUND 70 DEGREES. LOW LEVEL SOUTHERLY JET WILL INTENSIFY
OVER THE AREA OVERNIGHT...WITH BREEZY CONDITIONS AT TIMES IN THE
USUAL AREAS FROM NORTHEAST WY THROUGH SOUTHWEST INTO SOUTH CENTRAL
SD. ATMOSPHERE LOOKS TOO DRY TO GET ANY SHOWERS TO DEVELOP WITH THE
JET.

SUNDAY WILL SEE MOSTLY SUNNY TO PARTLY CLOUDY SKIES WITH HIGHS IN
THE 90S TO AROUND 100 DEGREES ON THE PLAINS AS THE THERMAL RIDGE
MOVES ACROSS WESTERN INTO CENTRAL SD DURING THE DAY. EXACT TIMING OF
THE COLD FRONT IS STILL A BIT UNCERTAIN...BUT IT SHOULD MOVE INTO
NORTHEAST WY LATE IN THE DAY AND ACROSS THE REST OF THE FORECAST
AREA SUNDAY NIGHT. WINDS WILL SWITCH TO THE WEST-NORTHWEST AND
BECOME BREEZY TO WINDY ACROSS NORTHWEST INTO WEST CENTRAL SD
OVERNIGHT. EMBEDDED ENERGY IN SOUTHWEST FLOW ALOFT WILL COMBINE WITH
THE FRONT TO PRODUCE AT LEAST ISOLATED SHOWERS AND STORMS OVER A
GOOD PORTION OF THE CWA SUNDAY NIGHT. THE THREAT FOR STRONG TO
SEVERE STORMS IS MINIMAL WITH THE TIMING OF THE FRONT...THOUGH WINDS
COULD GET GUSTY WITH SOME OF THE SHOWERS BEHIND THE FRONT.

.LONG TERM...MONDAY THROUGH SATURDAY
ISSUED AT 258 PM MDT SAT AUG 29 2015

NEGATIVE HEIGHT ANOMALY OVER THE PAC NW WILL REMAIN NEARLY
STATIONARY THROUGH THE PERIOD...WITH GENERALLY WARM CONDS OVER THE
NORTHERN PLAINS AS UPPER LEVEL SW FLOW PERSISTS. THE WESTERN NOAM
UPPER TROUGH WILL GRADUALLY SHIFT EAST AS A STRONGER NORTHERN
STREAM IMPULSE MERGES WITH IT...LEADING TOWARD BREAKDOWN OF THE
PERSISTENT RIDGE. IN THE MEANTIME...ABOVE NORMAL TEMPS WILL
PERSIST THROUGH MOST OF THE PERIOD...WITH MAINLY DRY CONDS. WEAK
COLD FRONT WILL ADVECT THROUGH THE AREA MONDAY MORNING...
SUPPORTING COOLER BUT STILL SEASONAL TEMPS IN A CAA REGIME MONDAY.
CENTRAL NOAM RIDGE WILL RE-SURGE TUE-THUR...WITH VERY WARM CONDS
EXPECTED ONCE AGAIN AS SOUTHERLY FLOW SPREADS OVER THE REGION.
WEAK SW FLOW IMPULSES COULD SUPPORT A FEW ISOLD SHRA/TS IN THE
TUE-WED PERIOD...ESP WITH ANY CONCENTRATED POS THETA-E ADV.
HOWEVER...LACK OF ANY APPRECIABLE SIGNALS PRECLUDE ANY POP
MENTION. NW PAC UPPER TROUGH WILL BIAS EAST BY THE END OF THE WEEK
WITH COOLER WEATHER LOOKING MORE LIKELY WITH INCREASING CHANCES
FOR RAIN.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 515 PM MDT SAT AUG 29 2015

VFR CONDITIONS WILL PREVAIL THROUGH SUNDAY AFTERNOON. LOW LEVEL
WIND SHEAR IS EXPECTED ON THE SD PLAINS LATER THIS EVENING THROUGH
SUNDAY MORNING AS A LOW LEVEL JET FROM 30-40KTS DEVELOPS.

&&

.FIRE WEATHER...
ISSUED AT 258 PM MDT SAT AUG 29 2015

WARM AND DRY CONDS WILL PERSIST ACROSS NE WY. RELATIVE HUMIDITY
ACROSS PORTIONS OF THE NORTHEAST WYOMING PLAINS WILL DROP TO 15
PERCENT OR BELOW THIS AFTERNOON AND AGAIN SUNDAY AFTERNOON. GUSTY
SOUTHWEST WINDS WILL CONTINUE THROUGH SUNDAY...AND ARE EXPECTED TO
BE STRONGEST SUNDAY AFTERNOON AHEAD OF A COLD FRONT. SW WINDS OF
20 TO 30 MPH WITH GUSTS TO AROUND 35 MPH ARE EXPECTED SUN.
PARTIALLY MIXED CONDS CAN BE EXPECTED TONIGHT GIVEN PRESSURE
FALLS...WITH SW WINDS CONTINUING UNDER POOR RH RECOVERY. WENT
AHEAD AND EXTENDED THE RED FLAG WARNING THROUGH SUNDAY AFTERNOON
FOR THIS.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
WY...RED FLAG WARNING UNTIL 8 PM MDT SUNDAY FOR WYZ259-297-298.

&&

$$

SHORT TERM...26
LONG TERM...JC
AVIATION...HELGESON
FIRE WEATHER...JC




000
FXUS63 KUNR 292316
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
516 PM MDT SAT AUG 29 2015

.SHORT TERM...THIS EVENING THROUGH SUNDAY NIGHT
ISSUED AT 258 PM MDT SAT AUG 29 2015

CURRENT SURFACE ANALYSIS SHOWS LOW PRESSURE OVER SK...WITH A COLD
FRONT TRAILING SOUTHWESTWARD INTO NORTHWEST MT AND NORTHERN ID. A
SURFACE TROF EXTENDS SOUTHWARD ACROSS EASTERN MT INTO NORTHEAST
WY. UPPER LEVEL ANALYSIS SHOWS RIDGING OVER THE ROCKIES AND INTO
THE HIGH PLAINS. FLOW ALOFT HAS BECOME WESTERLY OVER THE AREA AND
WILL BECOME SOUTHWESTERLY INTO TONIGHT. TEMPS ARE IN THE 90S
ACROSS THE PLAINS...WITH 80S IN THE BLACK HILLS. WINDS ARE SOUTH
TO SOUTHWEST...BREEZY ACROSS PORTIONS OF NORTHEAST WY. HAZY
SUNSHINE CONTINUES THROUGH THE SMOKE...THOUGH CONDITIONS APPEAR TO
BE GRADUALLY IMPROVING IN MOST AREAS THIS AFTERNOON.

AS RIDGE BUILDS OVER AND EAST OF THE AREA THROUGH THE WEEKEND...HOT
CONDITIONS CAN BE EXPECTED. THE COLD FRONT TO THE NORTHWEST OF THE
REGION WILL EVENTUALLY MAKE IT INTO THE FORECAST AREA LATE SUNDAY
AND SUNDAY NIGHT...BRINGING MOSTLY ISOLATED SHOWERS AND
THUNDERSTORMS...ALONG WITH COOLER AND BREEZY CONDITIONS BEHIND IT
INTO MONDAY.

FOR TONIGHT...SKIES WILL STAY MAINLY CLEAR WITH LOWS MOSTLY IN THE
60S TO AROUND 70 DEGREES. LOW LEVEL SOUTHERLY JET WILL INTENSIFY
OVER THE AREA OVERNIGHT...WITH BREEZY CONDITIONS AT TIMES IN THE
USUAL AREAS FROM NORTHEAST WY THROUGH SOUTHWEST INTO SOUTH CENTRAL
SD. ATMOSPHERE LOOKS TOO DRY TO GET ANY SHOWERS TO DEVELOP WITH THE
JET.

SUNDAY WILL SEE MOSTLY SUNNY TO PARTLY CLOUDY SKIES WITH HIGHS IN
THE 90S TO AROUND 100 DEGREES ON THE PLAINS AS THE THERMAL RIDGE
MOVES ACROSS WESTERN INTO CENTRAL SD DURING THE DAY. EXACT TIMING OF
THE COLD FRONT IS STILL A BIT UNCERTAIN...BUT IT SHOULD MOVE INTO
NORTHEAST WY LATE IN THE DAY AND ACROSS THE REST OF THE FORECAST
AREA SUNDAY NIGHT. WINDS WILL SWITCH TO THE WEST-NORTHWEST AND
BECOME BREEZY TO WINDY ACROSS NORTHWEST INTO WEST CENTRAL SD
OVERNIGHT. EMBEDDED ENERGY IN SOUTHWEST FLOW ALOFT WILL COMBINE WITH
THE FRONT TO PRODUCE AT LEAST ISOLATED SHOWERS AND STORMS OVER A
GOOD PORTION OF THE CWA SUNDAY NIGHT. THE THREAT FOR STRONG TO
SEVERE STORMS IS MINIMAL WITH THE TIMING OF THE FRONT...THOUGH WINDS
COULD GET GUSTY WITH SOME OF THE SHOWERS BEHIND THE FRONT.

.LONG TERM...MONDAY THROUGH SATURDAY
ISSUED AT 258 PM MDT SAT AUG 29 2015

NEGATIVE HEIGHT ANOMALY OVER THE PAC NW WILL REMAIN NEARLY
STATIONARY THROUGH THE PERIOD...WITH GENERALLY WARM CONDS OVER THE
NORTHERN PLAINS AS UPPER LEVEL SW FLOW PERSISTS. THE WESTERN NOAM
UPPER TROUGH WILL GRADUALLY SHIFT EAST AS A STRONGER NORTHERN
STREAM IMPULSE MERGES WITH IT...LEADING TOWARD BREAKDOWN OF THE
PERSISTENT RIDGE. IN THE MEANTIME...ABOVE NORMAL TEMPS WILL
PERSIST THROUGH MOST OF THE PERIOD...WITH MAINLY DRY CONDS. WEAK
COLD FRONT WILL ADVECT THROUGH THE AREA MONDAY MORNING...
SUPPORTING COOLER BUT STILL SEASONAL TEMPS IN A CAA REGIME MONDAY.
CENTRAL NOAM RIDGE WILL RE-SURGE TUE-THUR...WITH VERY WARM CONDS
EXPECTED ONCE AGAIN AS SOUTHERLY FLOW SPREADS OVER THE REGION.
WEAK SW FLOW IMPULSES COULD SUPPORT A FEW ISOLD SHRA/TS IN THE
TUE-WED PERIOD...ESP WITH ANY CONCENTRATED POS THETA-E ADV.
HOWEVER...LACK OF ANY APPRECIABLE SIGNALS PRECLUDE ANY POP
MENTION. NW PAC UPPER TROUGH WILL BIAS EAST BY THE END OF THE WEEK
WITH COOLER WEATHER LOOKING MORE LIKELY WITH INCREASING CHANCES
FOR RAIN.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 515 PM MDT SAT AUG 29 2015

VFR CONDITIONS WILL PREVAIL THROUGH SUNDAY AFTERNOON. LOW LEVEL
WIND SHEAR IS EXPECTED ON THE SD PLAINS LATER THIS EVENING THROUGH
SUNDAY MORNING AS A LOW LEVEL JET FROM 30-40KTS DEVELOPS.

&&

.FIRE WEATHER...
ISSUED AT 258 PM MDT SAT AUG 29 2015

WARM AND DRY CONDS WILL PERSIST ACROSS NE WY. RELATIVE HUMIDITY
ACROSS PORTIONS OF THE NORTHEAST WYOMING PLAINS WILL DROP TO 15
PERCENT OR BELOW THIS AFTERNOON AND AGAIN SUNDAY AFTERNOON. GUSTY
SOUTHWEST WINDS WILL CONTINUE THROUGH SUNDAY...AND ARE EXPECTED TO
BE STRONGEST SUNDAY AFTERNOON AHEAD OF A COLD FRONT. SW WINDS OF
20 TO 30 MPH WITH GUSTS TO AROUND 35 MPH ARE EXPECTED SUN.
PARTIALLY MIXED CONDS CAN BE EXPECTED TONIGHT GIVEN PRESSURE
FALLS...WITH SW WINDS CONTINUING UNDER POOR RH RECOVERY. WENT
AHEAD AND EXTENDED THE RED FLAG WARNING THROUGH SUNDAY AFTERNOON
FOR THIS.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
WY...RED FLAG WARNING UNTIL 8 PM MDT SUNDAY FOR WYZ259-297-298.

&&

$$

SHORT TERM...26
LONG TERM...JC
AVIATION...HELGESON
FIRE WEATHER...JC



000
FXUS63 KUNR 292316
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
516 PM MDT SAT AUG 29 2015

.SHORT TERM...THIS EVENING THROUGH SUNDAY NIGHT
ISSUED AT 258 PM MDT SAT AUG 29 2015

CURRENT SURFACE ANALYSIS SHOWS LOW PRESSURE OVER SK...WITH A COLD
FRONT TRAILING SOUTHWESTWARD INTO NORTHWEST MT AND NORTHERN ID. A
SURFACE TROF EXTENDS SOUTHWARD ACROSS EASTERN MT INTO NORTHEAST
WY. UPPER LEVEL ANALYSIS SHOWS RIDGING OVER THE ROCKIES AND INTO
THE HIGH PLAINS. FLOW ALOFT HAS BECOME WESTERLY OVER THE AREA AND
WILL BECOME SOUTHWESTERLY INTO TONIGHT. TEMPS ARE IN THE 90S
ACROSS THE PLAINS...WITH 80S IN THE BLACK HILLS. WINDS ARE SOUTH
TO SOUTHWEST...BREEZY ACROSS PORTIONS OF NORTHEAST WY. HAZY
SUNSHINE CONTINUES THROUGH THE SMOKE...THOUGH CONDITIONS APPEAR TO
BE GRADUALLY IMPROVING IN MOST AREAS THIS AFTERNOON.

AS RIDGE BUILDS OVER AND EAST OF THE AREA THROUGH THE WEEKEND...HOT
CONDITIONS CAN BE EXPECTED. THE COLD FRONT TO THE NORTHWEST OF THE
REGION WILL EVENTUALLY MAKE IT INTO THE FORECAST AREA LATE SUNDAY
AND SUNDAY NIGHT...BRINGING MOSTLY ISOLATED SHOWERS AND
THUNDERSTORMS...ALONG WITH COOLER AND BREEZY CONDITIONS BEHIND IT
INTO MONDAY.

FOR TONIGHT...SKIES WILL STAY MAINLY CLEAR WITH LOWS MOSTLY IN THE
60S TO AROUND 70 DEGREES. LOW LEVEL SOUTHERLY JET WILL INTENSIFY
OVER THE AREA OVERNIGHT...WITH BREEZY CONDITIONS AT TIMES IN THE
USUAL AREAS FROM NORTHEAST WY THROUGH SOUTHWEST INTO SOUTH CENTRAL
SD. ATMOSPHERE LOOKS TOO DRY TO GET ANY SHOWERS TO DEVELOP WITH THE
JET.

SUNDAY WILL SEE MOSTLY SUNNY TO PARTLY CLOUDY SKIES WITH HIGHS IN
THE 90S TO AROUND 100 DEGREES ON THE PLAINS AS THE THERMAL RIDGE
MOVES ACROSS WESTERN INTO CENTRAL SD DURING THE DAY. EXACT TIMING OF
THE COLD FRONT IS STILL A BIT UNCERTAIN...BUT IT SHOULD MOVE INTO
NORTHEAST WY LATE IN THE DAY AND ACROSS THE REST OF THE FORECAST
AREA SUNDAY NIGHT. WINDS WILL SWITCH TO THE WEST-NORTHWEST AND
BECOME BREEZY TO WINDY ACROSS NORTHWEST INTO WEST CENTRAL SD
OVERNIGHT. EMBEDDED ENERGY IN SOUTHWEST FLOW ALOFT WILL COMBINE WITH
THE FRONT TO PRODUCE AT LEAST ISOLATED SHOWERS AND STORMS OVER A
GOOD PORTION OF THE CWA SUNDAY NIGHT. THE THREAT FOR STRONG TO
SEVERE STORMS IS MINIMAL WITH THE TIMING OF THE FRONT...THOUGH WINDS
COULD GET GUSTY WITH SOME OF THE SHOWERS BEHIND THE FRONT.

.LONG TERM...MONDAY THROUGH SATURDAY
ISSUED AT 258 PM MDT SAT AUG 29 2015

NEGATIVE HEIGHT ANOMALY OVER THE PAC NW WILL REMAIN NEARLY
STATIONARY THROUGH THE PERIOD...WITH GENERALLY WARM CONDS OVER THE
NORTHERN PLAINS AS UPPER LEVEL SW FLOW PERSISTS. THE WESTERN NOAM
UPPER TROUGH WILL GRADUALLY SHIFT EAST AS A STRONGER NORTHERN
STREAM IMPULSE MERGES WITH IT...LEADING TOWARD BREAKDOWN OF THE
PERSISTENT RIDGE. IN THE MEANTIME...ABOVE NORMAL TEMPS WILL
PERSIST THROUGH MOST OF THE PERIOD...WITH MAINLY DRY CONDS. WEAK
COLD FRONT WILL ADVECT THROUGH THE AREA MONDAY MORNING...
SUPPORTING COOLER BUT STILL SEASONAL TEMPS IN A CAA REGIME MONDAY.
CENTRAL NOAM RIDGE WILL RE-SURGE TUE-THUR...WITH VERY WARM CONDS
EXPECTED ONCE AGAIN AS SOUTHERLY FLOW SPREADS OVER THE REGION.
WEAK SW FLOW IMPULSES COULD SUPPORT A FEW ISOLD SHRA/TS IN THE
TUE-WED PERIOD...ESP WITH ANY CONCENTRATED POS THETA-E ADV.
HOWEVER...LACK OF ANY APPRECIABLE SIGNALS PRECLUDE ANY POP
MENTION. NW PAC UPPER TROUGH WILL BIAS EAST BY THE END OF THE WEEK
WITH COOLER WEATHER LOOKING MORE LIKELY WITH INCREASING CHANCES
FOR RAIN.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 515 PM MDT SAT AUG 29 2015

VFR CONDITIONS WILL PREVAIL THROUGH SUNDAY AFTERNOON. LOW LEVEL
WIND SHEAR IS EXPECTED ON THE SD PLAINS LATER THIS EVENING THROUGH
SUNDAY MORNING AS A LOW LEVEL JET FROM 30-40KTS DEVELOPS.

&&

.FIRE WEATHER...
ISSUED AT 258 PM MDT SAT AUG 29 2015

WARM AND DRY CONDS WILL PERSIST ACROSS NE WY. RELATIVE HUMIDITY
ACROSS PORTIONS OF THE NORTHEAST WYOMING PLAINS WILL DROP TO 15
PERCENT OR BELOW THIS AFTERNOON AND AGAIN SUNDAY AFTERNOON. GUSTY
SOUTHWEST WINDS WILL CONTINUE THROUGH SUNDAY...AND ARE EXPECTED TO
BE STRONGEST SUNDAY AFTERNOON AHEAD OF A COLD FRONT. SW WINDS OF
20 TO 30 MPH WITH GUSTS TO AROUND 35 MPH ARE EXPECTED SUN.
PARTIALLY MIXED CONDS CAN BE EXPECTED TONIGHT GIVEN PRESSURE
FALLS...WITH SW WINDS CONTINUING UNDER POOR RH RECOVERY. WENT
AHEAD AND EXTENDED THE RED FLAG WARNING THROUGH SUNDAY AFTERNOON
FOR THIS.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
WY...RED FLAG WARNING UNTIL 8 PM MDT SUNDAY FOR WYZ259-297-298.

&&

$$

SHORT TERM...26
LONG TERM...JC
AVIATION...HELGESON
FIRE WEATHER...JC



000
FXUS63 KUNR 292316
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
516 PM MDT SAT AUG 29 2015

.SHORT TERM...THIS EVENING THROUGH SUNDAY NIGHT
ISSUED AT 258 PM MDT SAT AUG 29 2015

CURRENT SURFACE ANALYSIS SHOWS LOW PRESSURE OVER SK...WITH A COLD
FRONT TRAILING SOUTHWESTWARD INTO NORTHWEST MT AND NORTHERN ID. A
SURFACE TROF EXTENDS SOUTHWARD ACROSS EASTERN MT INTO NORTHEAST
WY. UPPER LEVEL ANALYSIS SHOWS RIDGING OVER THE ROCKIES AND INTO
THE HIGH PLAINS. FLOW ALOFT HAS BECOME WESTERLY OVER THE AREA AND
WILL BECOME SOUTHWESTERLY INTO TONIGHT. TEMPS ARE IN THE 90S
ACROSS THE PLAINS...WITH 80S IN THE BLACK HILLS. WINDS ARE SOUTH
TO SOUTHWEST...BREEZY ACROSS PORTIONS OF NORTHEAST WY. HAZY
SUNSHINE CONTINUES THROUGH THE SMOKE...THOUGH CONDITIONS APPEAR TO
BE GRADUALLY IMPROVING IN MOST AREAS THIS AFTERNOON.

AS RIDGE BUILDS OVER AND EAST OF THE AREA THROUGH THE WEEKEND...HOT
CONDITIONS CAN BE EXPECTED. THE COLD FRONT TO THE NORTHWEST OF THE
REGION WILL EVENTUALLY MAKE IT INTO THE FORECAST AREA LATE SUNDAY
AND SUNDAY NIGHT...BRINGING MOSTLY ISOLATED SHOWERS AND
THUNDERSTORMS...ALONG WITH COOLER AND BREEZY CONDITIONS BEHIND IT
INTO MONDAY.

FOR TONIGHT...SKIES WILL STAY MAINLY CLEAR WITH LOWS MOSTLY IN THE
60S TO AROUND 70 DEGREES. LOW LEVEL SOUTHERLY JET WILL INTENSIFY
OVER THE AREA OVERNIGHT...WITH BREEZY CONDITIONS AT TIMES IN THE
USUAL AREAS FROM NORTHEAST WY THROUGH SOUTHWEST INTO SOUTH CENTRAL
SD. ATMOSPHERE LOOKS TOO DRY TO GET ANY SHOWERS TO DEVELOP WITH THE
JET.

SUNDAY WILL SEE MOSTLY SUNNY TO PARTLY CLOUDY SKIES WITH HIGHS IN
THE 90S TO AROUND 100 DEGREES ON THE PLAINS AS THE THERMAL RIDGE
MOVES ACROSS WESTERN INTO CENTRAL SD DURING THE DAY. EXACT TIMING OF
THE COLD FRONT IS STILL A BIT UNCERTAIN...BUT IT SHOULD MOVE INTO
NORTHEAST WY LATE IN THE DAY AND ACROSS THE REST OF THE FORECAST
AREA SUNDAY NIGHT. WINDS WILL SWITCH TO THE WEST-NORTHWEST AND
BECOME BREEZY TO WINDY ACROSS NORTHWEST INTO WEST CENTRAL SD
OVERNIGHT. EMBEDDED ENERGY IN SOUTHWEST FLOW ALOFT WILL COMBINE WITH
THE FRONT TO PRODUCE AT LEAST ISOLATED SHOWERS AND STORMS OVER A
GOOD PORTION OF THE CWA SUNDAY NIGHT. THE THREAT FOR STRONG TO
SEVERE STORMS IS MINIMAL WITH THE TIMING OF THE FRONT...THOUGH WINDS
COULD GET GUSTY WITH SOME OF THE SHOWERS BEHIND THE FRONT.

.LONG TERM...MONDAY THROUGH SATURDAY
ISSUED AT 258 PM MDT SAT AUG 29 2015

NEGATIVE HEIGHT ANOMALY OVER THE PAC NW WILL REMAIN NEARLY
STATIONARY THROUGH THE PERIOD...WITH GENERALLY WARM CONDS OVER THE
NORTHERN PLAINS AS UPPER LEVEL SW FLOW PERSISTS. THE WESTERN NOAM
UPPER TROUGH WILL GRADUALLY SHIFT EAST AS A STRONGER NORTHERN
STREAM IMPULSE MERGES WITH IT...LEADING TOWARD BREAKDOWN OF THE
PERSISTENT RIDGE. IN THE MEANTIME...ABOVE NORMAL TEMPS WILL
PERSIST THROUGH MOST OF THE PERIOD...WITH MAINLY DRY CONDS. WEAK
COLD FRONT WILL ADVECT THROUGH THE AREA MONDAY MORNING...
SUPPORTING COOLER BUT STILL SEASONAL TEMPS IN A CAA REGIME MONDAY.
CENTRAL NOAM RIDGE WILL RE-SURGE TUE-THUR...WITH VERY WARM CONDS
EXPECTED ONCE AGAIN AS SOUTHERLY FLOW SPREADS OVER THE REGION.
WEAK SW FLOW IMPULSES COULD SUPPORT A FEW ISOLD SHRA/TS IN THE
TUE-WED PERIOD...ESP WITH ANY CONCENTRATED POS THETA-E ADV.
HOWEVER...LACK OF ANY APPRECIABLE SIGNALS PRECLUDE ANY POP
MENTION. NW PAC UPPER TROUGH WILL BIAS EAST BY THE END OF THE WEEK
WITH COOLER WEATHER LOOKING MORE LIKELY WITH INCREASING CHANCES
FOR RAIN.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 515 PM MDT SAT AUG 29 2015

VFR CONDITIONS WILL PREVAIL THROUGH SUNDAY AFTERNOON. LOW LEVEL
WIND SHEAR IS EXPECTED ON THE SD PLAINS LATER THIS EVENING THROUGH
SUNDAY MORNING AS A LOW LEVEL JET FROM 30-40KTS DEVELOPS.

&&

.FIRE WEATHER...
ISSUED AT 258 PM MDT SAT AUG 29 2015

WARM AND DRY CONDS WILL PERSIST ACROSS NE WY. RELATIVE HUMIDITY
ACROSS PORTIONS OF THE NORTHEAST WYOMING PLAINS WILL DROP TO 15
PERCENT OR BELOW THIS AFTERNOON AND AGAIN SUNDAY AFTERNOON. GUSTY
SOUTHWEST WINDS WILL CONTINUE THROUGH SUNDAY...AND ARE EXPECTED TO
BE STRONGEST SUNDAY AFTERNOON AHEAD OF A COLD FRONT. SW WINDS OF
20 TO 30 MPH WITH GUSTS TO AROUND 35 MPH ARE EXPECTED SUN.
PARTIALLY MIXED CONDS CAN BE EXPECTED TONIGHT GIVEN PRESSURE
FALLS...WITH SW WINDS CONTINUING UNDER POOR RH RECOVERY. WENT
AHEAD AND EXTENDED THE RED FLAG WARNING THROUGH SUNDAY AFTERNOON
FOR THIS.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
WY...RED FLAG WARNING UNTIL 8 PM MDT SUNDAY FOR WYZ259-297-298.

&&

$$

SHORT TERM...26
LONG TERM...JC
AVIATION...HELGESON
FIRE WEATHER...JC



000
FXUS63 KUNR 292316
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
516 PM MDT SAT AUG 29 2015

.SHORT TERM...THIS EVENING THROUGH SUNDAY NIGHT
ISSUED AT 258 PM MDT SAT AUG 29 2015

CURRENT SURFACE ANALYSIS SHOWS LOW PRESSURE OVER SK...WITH A COLD
FRONT TRAILING SOUTHWESTWARD INTO NORTHWEST MT AND NORTHERN ID. A
SURFACE TROF EXTENDS SOUTHWARD ACROSS EASTERN MT INTO NORTHEAST
WY. UPPER LEVEL ANALYSIS SHOWS RIDGING OVER THE ROCKIES AND INTO
THE HIGH PLAINS. FLOW ALOFT HAS BECOME WESTERLY OVER THE AREA AND
WILL BECOME SOUTHWESTERLY INTO TONIGHT. TEMPS ARE IN THE 90S
ACROSS THE PLAINS...WITH 80S IN THE BLACK HILLS. WINDS ARE SOUTH
TO SOUTHWEST...BREEZY ACROSS PORTIONS OF NORTHEAST WY. HAZY
SUNSHINE CONTINUES THROUGH THE SMOKE...THOUGH CONDITIONS APPEAR TO
BE GRADUALLY IMPROVING IN MOST AREAS THIS AFTERNOON.

AS RIDGE BUILDS OVER AND EAST OF THE AREA THROUGH THE WEEKEND...HOT
CONDITIONS CAN BE EXPECTED. THE COLD FRONT TO THE NORTHWEST OF THE
REGION WILL EVENTUALLY MAKE IT INTO THE FORECAST AREA LATE SUNDAY
AND SUNDAY NIGHT...BRINGING MOSTLY ISOLATED SHOWERS AND
THUNDERSTORMS...ALONG WITH COOLER AND BREEZY CONDITIONS BEHIND IT
INTO MONDAY.

FOR TONIGHT...SKIES WILL STAY MAINLY CLEAR WITH LOWS MOSTLY IN THE
60S TO AROUND 70 DEGREES. LOW LEVEL SOUTHERLY JET WILL INTENSIFY
OVER THE AREA OVERNIGHT...WITH BREEZY CONDITIONS AT TIMES IN THE
USUAL AREAS FROM NORTHEAST WY THROUGH SOUTHWEST INTO SOUTH CENTRAL
SD. ATMOSPHERE LOOKS TOO DRY TO GET ANY SHOWERS TO DEVELOP WITH THE
JET.

SUNDAY WILL SEE MOSTLY SUNNY TO PARTLY CLOUDY SKIES WITH HIGHS IN
THE 90S TO AROUND 100 DEGREES ON THE PLAINS AS THE THERMAL RIDGE
MOVES ACROSS WESTERN INTO CENTRAL SD DURING THE DAY. EXACT TIMING OF
THE COLD FRONT IS STILL A BIT UNCERTAIN...BUT IT SHOULD MOVE INTO
NORTHEAST WY LATE IN THE DAY AND ACROSS THE REST OF THE FORECAST
AREA SUNDAY NIGHT. WINDS WILL SWITCH TO THE WEST-NORTHWEST AND
BECOME BREEZY TO WINDY ACROSS NORTHWEST INTO WEST CENTRAL SD
OVERNIGHT. EMBEDDED ENERGY IN SOUTHWEST FLOW ALOFT WILL COMBINE WITH
THE FRONT TO PRODUCE AT LEAST ISOLATED SHOWERS AND STORMS OVER A
GOOD PORTION OF THE CWA SUNDAY NIGHT. THE THREAT FOR STRONG TO
SEVERE STORMS IS MINIMAL WITH THE TIMING OF THE FRONT...THOUGH WINDS
COULD GET GUSTY WITH SOME OF THE SHOWERS BEHIND THE FRONT.

.LONG TERM...MONDAY THROUGH SATURDAY
ISSUED AT 258 PM MDT SAT AUG 29 2015

NEGATIVE HEIGHT ANOMALY OVER THE PAC NW WILL REMAIN NEARLY
STATIONARY THROUGH THE PERIOD...WITH GENERALLY WARM CONDS OVER THE
NORTHERN PLAINS AS UPPER LEVEL SW FLOW PERSISTS. THE WESTERN NOAM
UPPER TROUGH WILL GRADUALLY SHIFT EAST AS A STRONGER NORTHERN
STREAM IMPULSE MERGES WITH IT...LEADING TOWARD BREAKDOWN OF THE
PERSISTENT RIDGE. IN THE MEANTIME...ABOVE NORMAL TEMPS WILL
PERSIST THROUGH MOST OF THE PERIOD...WITH MAINLY DRY CONDS. WEAK
COLD FRONT WILL ADVECT THROUGH THE AREA MONDAY MORNING...
SUPPORTING COOLER BUT STILL SEASONAL TEMPS IN A CAA REGIME MONDAY.
CENTRAL NOAM RIDGE WILL RE-SURGE TUE-THUR...WITH VERY WARM CONDS
EXPECTED ONCE AGAIN AS SOUTHERLY FLOW SPREADS OVER THE REGION.
WEAK SW FLOW IMPULSES COULD SUPPORT A FEW ISOLD SHRA/TS IN THE
TUE-WED PERIOD...ESP WITH ANY CONCENTRATED POS THETA-E ADV.
HOWEVER...LACK OF ANY APPRECIABLE SIGNALS PRECLUDE ANY POP
MENTION. NW PAC UPPER TROUGH WILL BIAS EAST BY THE END OF THE WEEK
WITH COOLER WEATHER LOOKING MORE LIKELY WITH INCREASING CHANCES
FOR RAIN.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 515 PM MDT SAT AUG 29 2015

VFR CONDITIONS WILL PREVAIL THROUGH SUNDAY AFTERNOON. LOW LEVEL
WIND SHEAR IS EXPECTED ON THE SD PLAINS LATER THIS EVENING THROUGH
SUNDAY MORNING AS A LOW LEVEL JET FROM 30-40KTS DEVELOPS.

&&

.FIRE WEATHER...
ISSUED AT 258 PM MDT SAT AUG 29 2015

WARM AND DRY CONDS WILL PERSIST ACROSS NE WY. RELATIVE HUMIDITY
ACROSS PORTIONS OF THE NORTHEAST WYOMING PLAINS WILL DROP TO 15
PERCENT OR BELOW THIS AFTERNOON AND AGAIN SUNDAY AFTERNOON. GUSTY
SOUTHWEST WINDS WILL CONTINUE THROUGH SUNDAY...AND ARE EXPECTED TO
BE STRONGEST SUNDAY AFTERNOON AHEAD OF A COLD FRONT. SW WINDS OF
20 TO 30 MPH WITH GUSTS TO AROUND 35 MPH ARE EXPECTED SUN.
PARTIALLY MIXED CONDS CAN BE EXPECTED TONIGHT GIVEN PRESSURE
FALLS...WITH SW WINDS CONTINUING UNDER POOR RH RECOVERY. WENT
AHEAD AND EXTENDED THE RED FLAG WARNING THROUGH SUNDAY AFTERNOON
FOR THIS.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
WY...RED FLAG WARNING UNTIL 8 PM MDT SUNDAY FOR WYZ259-297-298.

&&

$$

SHORT TERM...26
LONG TERM...JC
AVIATION...HELGESON
FIRE WEATHER...JC



000
FXUS63 KUNR 292316
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
516 PM MDT SAT AUG 29 2015

.SHORT TERM...THIS EVENING THROUGH SUNDAY NIGHT
ISSUED AT 258 PM MDT SAT AUG 29 2015

CURRENT SURFACE ANALYSIS SHOWS LOW PRESSURE OVER SK...WITH A COLD
FRONT TRAILING SOUTHWESTWARD INTO NORTHWEST MT AND NORTHERN ID. A
SURFACE TROF EXTENDS SOUTHWARD ACROSS EASTERN MT INTO NORTHEAST
WY. UPPER LEVEL ANALYSIS SHOWS RIDGING OVER THE ROCKIES AND INTO
THE HIGH PLAINS. FLOW ALOFT HAS BECOME WESTERLY OVER THE AREA AND
WILL BECOME SOUTHWESTERLY INTO TONIGHT. TEMPS ARE IN THE 90S
ACROSS THE PLAINS...WITH 80S IN THE BLACK HILLS. WINDS ARE SOUTH
TO SOUTHWEST...BREEZY ACROSS PORTIONS OF NORTHEAST WY. HAZY
SUNSHINE CONTINUES THROUGH THE SMOKE...THOUGH CONDITIONS APPEAR TO
BE GRADUALLY IMPROVING IN MOST AREAS THIS AFTERNOON.

AS RIDGE BUILDS OVER AND EAST OF THE AREA THROUGH THE WEEKEND...HOT
CONDITIONS CAN BE EXPECTED. THE COLD FRONT TO THE NORTHWEST OF THE
REGION WILL EVENTUALLY MAKE IT INTO THE FORECAST AREA LATE SUNDAY
AND SUNDAY NIGHT...BRINGING MOSTLY ISOLATED SHOWERS AND
THUNDERSTORMS...ALONG WITH COOLER AND BREEZY CONDITIONS BEHIND IT
INTO MONDAY.

FOR TONIGHT...SKIES WILL STAY MAINLY CLEAR WITH LOWS MOSTLY IN THE
60S TO AROUND 70 DEGREES. LOW LEVEL SOUTHERLY JET WILL INTENSIFY
OVER THE AREA OVERNIGHT...WITH BREEZY CONDITIONS AT TIMES IN THE
USUAL AREAS FROM NORTHEAST WY THROUGH SOUTHWEST INTO SOUTH CENTRAL
SD. ATMOSPHERE LOOKS TOO DRY TO GET ANY SHOWERS TO DEVELOP WITH THE
JET.

SUNDAY WILL SEE MOSTLY SUNNY TO PARTLY CLOUDY SKIES WITH HIGHS IN
THE 90S TO AROUND 100 DEGREES ON THE PLAINS AS THE THERMAL RIDGE
MOVES ACROSS WESTERN INTO CENTRAL SD DURING THE DAY. EXACT TIMING OF
THE COLD FRONT IS STILL A BIT UNCERTAIN...BUT IT SHOULD MOVE INTO
NORTHEAST WY LATE IN THE DAY AND ACROSS THE REST OF THE FORECAST
AREA SUNDAY NIGHT. WINDS WILL SWITCH TO THE WEST-NORTHWEST AND
BECOME BREEZY TO WINDY ACROSS NORTHWEST INTO WEST CENTRAL SD
OVERNIGHT. EMBEDDED ENERGY IN SOUTHWEST FLOW ALOFT WILL COMBINE WITH
THE FRONT TO PRODUCE AT LEAST ISOLATED SHOWERS AND STORMS OVER A
GOOD PORTION OF THE CWA SUNDAY NIGHT. THE THREAT FOR STRONG TO
SEVERE STORMS IS MINIMAL WITH THE TIMING OF THE FRONT...THOUGH WINDS
COULD GET GUSTY WITH SOME OF THE SHOWERS BEHIND THE FRONT.

.LONG TERM...MONDAY THROUGH SATURDAY
ISSUED AT 258 PM MDT SAT AUG 29 2015

NEGATIVE HEIGHT ANOMALY OVER THE PAC NW WILL REMAIN NEARLY
STATIONARY THROUGH THE PERIOD...WITH GENERALLY WARM CONDS OVER THE
NORTHERN PLAINS AS UPPER LEVEL SW FLOW PERSISTS. THE WESTERN NOAM
UPPER TROUGH WILL GRADUALLY SHIFT EAST AS A STRONGER NORTHERN
STREAM IMPULSE MERGES WITH IT...LEADING TOWARD BREAKDOWN OF THE
PERSISTENT RIDGE. IN THE MEANTIME...ABOVE NORMAL TEMPS WILL
PERSIST THROUGH MOST OF THE PERIOD...WITH MAINLY DRY CONDS. WEAK
COLD FRONT WILL ADVECT THROUGH THE AREA MONDAY MORNING...
SUPPORTING COOLER BUT STILL SEASONAL TEMPS IN A CAA REGIME MONDAY.
CENTRAL NOAM RIDGE WILL RE-SURGE TUE-THUR...WITH VERY WARM CONDS
EXPECTED ONCE AGAIN AS SOUTHERLY FLOW SPREADS OVER THE REGION.
WEAK SW FLOW IMPULSES COULD SUPPORT A FEW ISOLD SHRA/TS IN THE
TUE-WED PERIOD...ESP WITH ANY CONCENTRATED POS THETA-E ADV.
HOWEVER...LACK OF ANY APPRECIABLE SIGNALS PRECLUDE ANY POP
MENTION. NW PAC UPPER TROUGH WILL BIAS EAST BY THE END OF THE WEEK
WITH COOLER WEATHER LOOKING MORE LIKELY WITH INCREASING CHANCES
FOR RAIN.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 515 PM MDT SAT AUG 29 2015

VFR CONDITIONS WILL PREVAIL THROUGH SUNDAY AFTERNOON. LOW LEVEL
WIND SHEAR IS EXPECTED ON THE SD PLAINS LATER THIS EVENING THROUGH
SUNDAY MORNING AS A LOW LEVEL JET FROM 30-40KTS DEVELOPS.

&&

.FIRE WEATHER...
ISSUED AT 258 PM MDT SAT AUG 29 2015

WARM AND DRY CONDS WILL PERSIST ACROSS NE WY. RELATIVE HUMIDITY
ACROSS PORTIONS OF THE NORTHEAST WYOMING PLAINS WILL DROP TO 15
PERCENT OR BELOW THIS AFTERNOON AND AGAIN SUNDAY AFTERNOON. GUSTY
SOUTHWEST WINDS WILL CONTINUE THROUGH SUNDAY...AND ARE EXPECTED TO
BE STRONGEST SUNDAY AFTERNOON AHEAD OF A COLD FRONT. SW WINDS OF
20 TO 30 MPH WITH GUSTS TO AROUND 35 MPH ARE EXPECTED SUN.
PARTIALLY MIXED CONDS CAN BE EXPECTED TONIGHT GIVEN PRESSURE
FALLS...WITH SW WINDS CONTINUING UNDER POOR RH RECOVERY. WENT
AHEAD AND EXTENDED THE RED FLAG WARNING THROUGH SUNDAY AFTERNOON
FOR THIS.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
WY...RED FLAG WARNING UNTIL 8 PM MDT SUNDAY FOR WYZ259-297-298.

&&

$$

SHORT TERM...26
LONG TERM...JC
AVIATION...HELGESON
FIRE WEATHER...JC



000
FXUS65 KCYS 292137
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
337 PM MDT SAT AUG 29 2015

.SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT)
ISSUED AT 300 PM MDT SAT AUG 29 2015

FORECAST CHALLENGES DEAL WITH WINDS...PRECIPITATION CHANCES AND
POSSIBLE FIRE WEATHER CONCERNS THROUGH THE SHORT TERM.

CURRENTLY...LATEST VISIBLE SATELLITE IMAGERY FROM THIS MORNING
SHOWING ELEVATED SMOKE HANGING TOUGH OVER AREAS EAST OF THE
LARAMIE RANGE. LOW PRESSURE OFF THE COAST OF WASHINGTON STATE WITH
A FRONTAL SYSTEM BEING ANALYZED NEAR THE IDAHO/OREGON
BORDER...EXTENDING UP INTO ALBERTA CANADA. SOUTHEAST WYOMING
REMAINS UNDER AN UPPER RIDGE AXIS WITH FAIRLY LIGHT WINDS FOR THIS
PART OF THE COUNTRY.

RIDGE AXIS SHIFTS EAST THIS EVENING WITH 700MB SOUTHWESTERLY WINDS
INCREASING ACROSS CARBON AND ALBANY COUNTIES. AS HAS BEEN THE CASE
THE PAST WEEK...MODELS CONTINUE TO SHOW STRONG 850MB WINDS ACROSS
THE PANHANDLE THIS EVENING...UP TO 35-40KTS. COULD BE A LOW LEVEL
JET SETTING UP OUT THERE. FORECAST SOUNDINGS DO SHOW A LOW LEVEL
INVERSION SETTING UP THAT COULD SHELTER THE PANHANDLE FROM THESE
WINDS. BUT IF THE INVERSION DOES NOT SET UP...COULD BE DEALING
WITH ADVISORY LEVEL WINDS OUT THERE TONIGHT.

UPPER SHORTWAVE TROUGH MOVES INTO WESTERN MONTANA SUNDAY
AFTERNOON. STRONG 700MB WINDS OF 35-40KTS ACROSS CARBON AND ALBANY
COUNTIES AS WELL AS CONVERSE/NIOBRARA COUNTIES AND NORTH LARAMIE
RANGE. PRECIP DELAYED INTO THE AREA UNTIL LATE AFTERNOON...INTO
THE EVENING HOURS. DID UPGRADE THE FIRE WEATHER WATCH FOR
CONVERSE/NIOBRARA COUNTIES TO A RED FLAG WARNING THIS AFTERNOON. NIGHT
SHIFT WILL NEED TO CONSIDER NORTHERN 309 AND 310 AS WELL AS WE
SHOULD BE VERY DRY UP THERE WITH POOR OVERNIGHT HUMIDITY
RECOVERIES.

CONVECTION MOVES INTO OUR WESTERN ZONES LATE SUNDAY
AFTERNOON...PERSISTING INTO THE EVENING HOURS. GFS BY FAR THE
MOST BULLISH ON POPS OVER THE ECMWF AND NAM. DID DECREASE POPS
SOME FOR OUR EASTERN ZONES TOMORROW AFTERNOON.

LOOK FOR FRONTAL PASSAGE NEAR MIDNIGHT MONDAY MORNING WITH COOLER
AIR SPREADING INTO THE AREA FOR MONDAY.

.LONG TERM...(TUESDAY THROUGH SATURDAY)

ISSUED AT 338 PM MDT SAT AUG 29 2015

AFTER THE FRONTAL PASSAGE ON MONDAY... LINGERING MOISTURE ON
TUESDAY MAY CAUSE A FEW SHOWERS AND THUNDERSTORMS OVER THE SIERRA
MADRE AND SNOWY RANGES. GENERALLY SOUTHWESTERLY FLOW ALOFT WILL
PREVAIL FOR MOST OF THE CWA WITH AN UPPER LEVEL RIDGE BUILDING
OVERHEAD. THIS WILL BRING WARMER TEMPERATURES AND DRIER CONDITIONS
THROUGHOUT THE WEEK. WITH LACK OF ANY FORCING AND DRIER LOW LEVELS...
POP CHANCES WILL REMAIN LOW WEDNESDAY AND THURSDAY. FRIDAY THE
CHANCES FOR SHOWERS AND THUNDERSTORMS INCREASE WITH THE PASSAGE OF
AN UPPER LEVEL TROUGH... MAINLY EFFECTING EAST OF THE LARAMIE
RANGE INTO THE NEBRASKA PANHANDLE.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1132 AM MDT SAT AUG 29 2015

MOSTLY VFR CONDITIONS WILL BE PRESENT... WITH THE EXCEPTION OF
SMOKE CAUSING OCCASIONAL SLIGHT DECREASE TO VISIBILITIES... DOWN
TO 5 MILES IN CHADRON. AS WINDS SHIFT TO THE SOUTHWEST THIS
AFTERNOON... SMOKE SHOULD BLOW OUT OF THE AREA BY TONIGHT. HIGHER
WIND GUSTS CAN BE EXPECTED INTO CHADRON TONIGHT FROM THE FORMATION
OF A LOW LEVEL JET... WIND GUSTS ARE EXPECTED TO BE AROUND 25KT.
OTHERWISE... LIGHTER WINDS ARE EXPECTED OVER THE REST OF THE
AREA.

&&

.FIRE WEATHER...
ISSUED AT 110 PM MDT SAT AUG 29 2015

INCREASING WINDS TONIGHT INTO SUNDAY AS LOW PRESSURE TRACKS INTO
MONTANA SUNDAY AFTERNOON. CHALLENGING FORECAST AS WIND SPEEDS
COULD BE OFFSET BY INCREASING CLOUDS...WHICH WOULD LIMIT MIXING.
WILL KEEP RED FLAG WARNING FOR FWZ 301 FOR SUNDAY LATE MORNING
THROUGH THE AFTERNOON. INCREASING MOISTURE SUNDAY AFTERNOON ACROSS
CARBON AND ALBANY COUNTIES WILL GIVE CHANCES FOR WETTING RAINS OUT
THAT WAY FROM MID AFTERNOON THROUGH MID EVENING. WINDY PERIOD
AHEAD AS THE LOW SLOWLY TRACKS ACROSS MONTANA.
&&

.CYS WATCHES/WARNINGS/ADVISORIES...

WY...RED FLAG WARNING FROM 11 AM TO 7 PM MDT SUNDAY FOR WYZ301.

NE...NONE.

&&

$$

SHORT TERM...GCC
LONG TERM...SML/KC
AVIATION...SML/KC
FIRE WEATHER...GCC




000
FXUS63 KUNR 292059
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
259 PM MDT SAT AUG 29 2015

.SHORT TERM...THIS EVENING THROUGH SUNDAY NIGHT
ISSUED AT 258 PM MDT SAT AUG 29 2015

CURRENT SURFACE ANALYSIS SHOWS LOW PRESSURE OVER SK...WITH A COLD
FRONT TRAILING SOUTHWESTWARD INTO NORTHWEST MT AND NORTHERN ID. A
SURFACE TROF EXTENDS SOUTHWARD ACROSS EASTERN MT INTO NORTHEAST
WY. UPPER LEVEL ANALYSIS SHOWS RIDGING OVER THE ROCKIES AND INTO
THE HIGH PLAINS. FLOW ALOFT HAS BECOME WESTERLY OVER THE AREA AND
WILL BECOME SOUTHWESTERLY INTO TONIGHT. TEMPS ARE IN THE 90S
ACROSS THE PLAINS...WITH 80S IN THE BLACK HILLS. WINDS ARE SOUTH
TO SOUTHWEST...BREEZY ACROSS PORTIONS OF NORTHEAST WY. HAZY
SUNSHINE CONTINUES THROUGH THE SMOKE...THOUGH CONDITIONS APPEAR TO
BE GRADUALLY IMPROVING IN MOST AREAS THIS AFTERNOON.

AS RIDGE BUILDS OVER AND EAST OF THE AREA THROUGH THE WEEKEND...HOT
CONDITIONS CAN BE EXPECTED. THE COLD FRONT TO THE NORTHWEST OF THE
REGION WILL EVENTUALLY MAKE IT INTO THE FORECAST AREA LATE SUNDAY
AND SUNDAY NIGHT...BRINGING MOSTLY ISOLATED SHOWERS AND
THUNDERSTORMS...ALONG WITH COOLER AND BREEZY CONDITIONS BEHIND IT
INTO MONDAY.

FOR TONIGHT...SKIES WILL STAY MAINLY CLEAR WITH LOWS MOSTLY IN THE
60S TO AROUND 70 DEGREES. LOW LEVEL SOUTHERLY JET WILL INTENSIFY
OVER THE AREA OVERNIGHT...WITH BREEZY CONDITIONS AT TIMES IN THE
USUAL AREAS FROM NORTHEAST WY THROUGH SOUTHWEST INTO SOUTH CENTRAL
SD. ATMOSPHERE LOOKS TOO DRY TO GET ANY SHOWERS TO DEVELOP WITH THE
JET.

SUNDAY WILL SEE MOSTLY SUNNY TO PARTLY CLOUDY SKIES WITH HIGHS IN
THE 90S TO AROUND 100 DEGREES ON THE PLAINS AS THE THERMAL RIDGE
MOVES ACROSS WESTERN INTO CENTRAL SD DURING THE DAY. EXACT TIMING OF
THE COLD FRONT IS STILL A BIT UNCERTAIN...BUT IT SHOULD MOVE INTO
NORTHEAST WY LATE IN THE DAY AND ACROSS THE REST OF THE FORECAST
AREA SUNDAY NIGHT. WINDS WILL SWITCH TO THE WEST-NORTHWEST AND
BECOME BREEZY TO WINDY ACROSS NORTHWEST INTO WEST CENTRAL SD
OVERNIGHT. EMBEDDED ENERGY IN SOUTHWEST FLOW ALOFT WILL COMBINE WITH
THE FRONT TO PRODUCE AT LEAST ISOLATED SHOWERS AND STORMS OVER A
GOOD PORTION OF THE CWA SUNDAY NIGHT. THE THREAT FOR STRONG TO
SEVERE STORMS IS MINIMAL WITH THE TIMING OF THE FRONT...THOUGH WINDS
COULD GET GUSTY WITH SOME OF THE SHOWERS BEHIND THE FRONT.


.LONG TERM...MONDAY THROUGH SATURDAY
ISSUED AT 258 PM MDT SAT AUG 29 2015

NEGATIVE HEIGHT ANOMALY OVER THE PAC NW WILL REMAIN NEARLY
STATIONARY THROUGH THE PERIOD...WITH GENERALLY WARM CONDS OVER THE
NORTHERN PLAINS AS UPPER LEVEL SW FLOW PERSISTS. THE WESTERN NOAM
UPPER TROUGH WILL GRADUALLY SHIFT EAST AS A STRONGER NORTHERN
STREAM IMPULSE MERGES WITH IT...LEADING TOWARD BREAKDOWN OF THE
PERSISTENT RIDGE. IN THE MEANTIME...ABOVE NORMAL TEMPS WILL
PERSIST THROUGH MOST OF THE PERIOD...WITH MAINLY DRY CONDS. WEAK
COLD FRONT WILL ADVECT THROUGH THE AREA MONDAY MORNING...
SUPPORTING COOLER BUT STILL SEASONAL TEMPS IN A CAA REGIME MONDAY.
CENTRAL NOAM RIDGE WILL RE-SURGE TUE-THUR...WITH VERY WARM CONDS
EXPECTED ONCE AGAIN AS SOUTHERLY FLOW SPREADS OVER THE REGION.
WEAK SW FLOW IMPULSES COULD SUPPORT A FEW ISOLD SHRA/TS IN THE
TUE-WED PERIOD...ESP WITH ANY CONCENTRATED POS THETA-E ADV.
HOWEVER...LACK OF ANY APPRECIABLE SIGNALS PRECLUDE ANY POP
MENTION. NW PAC UPPER TROUGH WILL BIAS EAST BY THE END OF THE WEEK
WITH COOLER WEATHER LOOKING MORE LIKELY WITH INCREASING CHANCES
FOR RAIN.

&&

.AVIATION...FOR THE 18Z TAFS THROUGH 18Z SUNDAY
ISSUED AT 258 PM MDT SAT AUG 29 2015

MAINLY VFR CONDS WITH ISOLD MVFR VIS POSSIBLE IN SMOKE FROM
WESTERN WILDFIRES.

&&

.FIRE WEATHER...
ISSUED AT 258 PM MDT SAT AUG 29 2015

WARM AND DRY CONDS WILL PERSIST ACROSS NE WY. RELATIVE HUMIDITY
ACROSS PORTIONS OF THE NORTHEAST WYOMING PLAINS WILL DROP TO 15
PERCENT OR BELOW THIS AFTERNOON AND AGAIN SUNDAY AFTERNOON. GUSTY
SOUTHWEST WINDS WILL CONTINUE THROUGH SUNDAY...AND ARE EXPECTED TO
BE STRONGEST SUNDAY AFTERNOON AHEAD OF A COLD FRONT. SW WINDS OF
20 TO 30 MPH WITH GUSTS TO AROUND 35 MPH ARE EXPECTED SUN.
PARTIALLY MIXED CONDS CAN BE EXPECTED TONIGHT GIVEN PRESSURE
FALLS...WITH SW WINDS CONTINUING UNDER POOR RH RECOVERY. WENT
AHEAD AND EXTENDED THE RED FLAG WARNING THROUGH SUNDAY AFTERNOON
FOR THIS.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
WY...RED FLAG WARNING UNTIL 8 PM MDT SUNDAY FOR WYZ259-297-298.

&&

$$

SHORT TERM...26
LONG TERM...JC
AVIATION...JC
FIRE WEATHER...JC



000
FXUS63 KUNR 292059
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
259 PM MDT SAT AUG 29 2015

.SHORT TERM...THIS EVENING THROUGH SUNDAY NIGHT
ISSUED AT 258 PM MDT SAT AUG 29 2015

CURRENT SURFACE ANALYSIS SHOWS LOW PRESSURE OVER SK...WITH A COLD
FRONT TRAILING SOUTHWESTWARD INTO NORTHWEST MT AND NORTHERN ID. A
SURFACE TROF EXTENDS SOUTHWARD ACROSS EASTERN MT INTO NORTHEAST
WY. UPPER LEVEL ANALYSIS SHOWS RIDGING OVER THE ROCKIES AND INTO
THE HIGH PLAINS. FLOW ALOFT HAS BECOME WESTERLY OVER THE AREA AND
WILL BECOME SOUTHWESTERLY INTO TONIGHT. TEMPS ARE IN THE 90S
ACROSS THE PLAINS...WITH 80S IN THE BLACK HILLS. WINDS ARE SOUTH
TO SOUTHWEST...BREEZY ACROSS PORTIONS OF NORTHEAST WY. HAZY
SUNSHINE CONTINUES THROUGH THE SMOKE...THOUGH CONDITIONS APPEAR TO
BE GRADUALLY IMPROVING IN MOST AREAS THIS AFTERNOON.

AS RIDGE BUILDS OVER AND EAST OF THE AREA THROUGH THE WEEKEND...HOT
CONDITIONS CAN BE EXPECTED. THE COLD FRONT TO THE NORTHWEST OF THE
REGION WILL EVENTUALLY MAKE IT INTO THE FORECAST AREA LATE SUNDAY
AND SUNDAY NIGHT...BRINGING MOSTLY ISOLATED SHOWERS AND
THUNDERSTORMS...ALONG WITH COOLER AND BREEZY CONDITIONS BEHIND IT
INTO MONDAY.

FOR TONIGHT...SKIES WILL STAY MAINLY CLEAR WITH LOWS MOSTLY IN THE
60S TO AROUND 70 DEGREES. LOW LEVEL SOUTHERLY JET WILL INTENSIFY
OVER THE AREA OVERNIGHT...WITH BREEZY CONDITIONS AT TIMES IN THE
USUAL AREAS FROM NORTHEAST WY THROUGH SOUTHWEST INTO SOUTH CENTRAL
SD. ATMOSPHERE LOOKS TOO DRY TO GET ANY SHOWERS TO DEVELOP WITH THE
JET.

SUNDAY WILL SEE MOSTLY SUNNY TO PARTLY CLOUDY SKIES WITH HIGHS IN
THE 90S TO AROUND 100 DEGREES ON THE PLAINS AS THE THERMAL RIDGE
MOVES ACROSS WESTERN INTO CENTRAL SD DURING THE DAY. EXACT TIMING OF
THE COLD FRONT IS STILL A BIT UNCERTAIN...BUT IT SHOULD MOVE INTO
NORTHEAST WY LATE IN THE DAY AND ACROSS THE REST OF THE FORECAST
AREA SUNDAY NIGHT. WINDS WILL SWITCH TO THE WEST-NORTHWEST AND
BECOME BREEZY TO WINDY ACROSS NORTHWEST INTO WEST CENTRAL SD
OVERNIGHT. EMBEDDED ENERGY IN SOUTHWEST FLOW ALOFT WILL COMBINE WITH
THE FRONT TO PRODUCE AT LEAST ISOLATED SHOWERS AND STORMS OVER A
GOOD PORTION OF THE CWA SUNDAY NIGHT. THE THREAT FOR STRONG TO
SEVERE STORMS IS MINIMAL WITH THE TIMING OF THE FRONT...THOUGH WINDS
COULD GET GUSTY WITH SOME OF THE SHOWERS BEHIND THE FRONT.


.LONG TERM...MONDAY THROUGH SATURDAY
ISSUED AT 258 PM MDT SAT AUG 29 2015

NEGATIVE HEIGHT ANOMALY OVER THE PAC NW WILL REMAIN NEARLY
STATIONARY THROUGH THE PERIOD...WITH GENERALLY WARM CONDS OVER THE
NORTHERN PLAINS AS UPPER LEVEL SW FLOW PERSISTS. THE WESTERN NOAM
UPPER TROUGH WILL GRADUALLY SHIFT EAST AS A STRONGER NORTHERN
STREAM IMPULSE MERGES WITH IT...LEADING TOWARD BREAKDOWN OF THE
PERSISTENT RIDGE. IN THE MEANTIME...ABOVE NORMAL TEMPS WILL
PERSIST THROUGH MOST OF THE PERIOD...WITH MAINLY DRY CONDS. WEAK
COLD FRONT WILL ADVECT THROUGH THE AREA MONDAY MORNING...
SUPPORTING COOLER BUT STILL SEASONAL TEMPS IN A CAA REGIME MONDAY.
CENTRAL NOAM RIDGE WILL RE-SURGE TUE-THUR...WITH VERY WARM CONDS
EXPECTED ONCE AGAIN AS SOUTHERLY FLOW SPREADS OVER THE REGION.
WEAK SW FLOW IMPULSES COULD SUPPORT A FEW ISOLD SHRA/TS IN THE
TUE-WED PERIOD...ESP WITH ANY CONCENTRATED POS THETA-E ADV.
HOWEVER...LACK OF ANY APPRECIABLE SIGNALS PRECLUDE ANY POP
MENTION. NW PAC UPPER TROUGH WILL BIAS EAST BY THE END OF THE WEEK
WITH COOLER WEATHER LOOKING MORE LIKELY WITH INCREASING CHANCES
FOR RAIN.

&&

.AVIATION...FOR THE 18Z TAFS THROUGH 18Z SUNDAY
ISSUED AT 258 PM MDT SAT AUG 29 2015

MAINLY VFR CONDS WITH ISOLD MVFR VIS POSSIBLE IN SMOKE FROM
WESTERN WILDFIRES.

&&

.FIRE WEATHER...
ISSUED AT 258 PM MDT SAT AUG 29 2015

WARM AND DRY CONDS WILL PERSIST ACROSS NE WY. RELATIVE HUMIDITY
ACROSS PORTIONS OF THE NORTHEAST WYOMING PLAINS WILL DROP TO 15
PERCENT OR BELOW THIS AFTERNOON AND AGAIN SUNDAY AFTERNOON. GUSTY
SOUTHWEST WINDS WILL CONTINUE THROUGH SUNDAY...AND ARE EXPECTED TO
BE STRONGEST SUNDAY AFTERNOON AHEAD OF A COLD FRONT. SW WINDS OF
20 TO 30 MPH WITH GUSTS TO AROUND 35 MPH ARE EXPECTED SUN.
PARTIALLY MIXED CONDS CAN BE EXPECTED TONIGHT GIVEN PRESSURE
FALLS...WITH SW WINDS CONTINUING UNDER POOR RH RECOVERY. WENT
AHEAD AND EXTENDED THE RED FLAG WARNING THROUGH SUNDAY AFTERNOON
FOR THIS.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
WY...RED FLAG WARNING UNTIL 8 PM MDT SUNDAY FOR WYZ259-297-298.

&&

$$

SHORT TERM...26
LONG TERM...JC
AVIATION...JC
FIRE WEATHER...JC



000
FXUS63 KUNR 292059
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
259 PM MDT SAT AUG 29 2015

.SHORT TERM...THIS EVENING THROUGH SUNDAY NIGHT
ISSUED AT 258 PM MDT SAT AUG 29 2015

CURRENT SURFACE ANALYSIS SHOWS LOW PRESSURE OVER SK...WITH A COLD
FRONT TRAILING SOUTHWESTWARD INTO NORTHWEST MT AND NORTHERN ID. A
SURFACE TROF EXTENDS SOUTHWARD ACROSS EASTERN MT INTO NORTHEAST
WY. UPPER LEVEL ANALYSIS SHOWS RIDGING OVER THE ROCKIES AND INTO
THE HIGH PLAINS. FLOW ALOFT HAS BECOME WESTERLY OVER THE AREA AND
WILL BECOME SOUTHWESTERLY INTO TONIGHT. TEMPS ARE IN THE 90S
ACROSS THE PLAINS...WITH 80S IN THE BLACK HILLS. WINDS ARE SOUTH
TO SOUTHWEST...BREEZY ACROSS PORTIONS OF NORTHEAST WY. HAZY
SUNSHINE CONTINUES THROUGH THE SMOKE...THOUGH CONDITIONS APPEAR TO
BE GRADUALLY IMPROVING IN MOST AREAS THIS AFTERNOON.

AS RIDGE BUILDS OVER AND EAST OF THE AREA THROUGH THE WEEKEND...HOT
CONDITIONS CAN BE EXPECTED. THE COLD FRONT TO THE NORTHWEST OF THE
REGION WILL EVENTUALLY MAKE IT INTO THE FORECAST AREA LATE SUNDAY
AND SUNDAY NIGHT...BRINGING MOSTLY ISOLATED SHOWERS AND
THUNDERSTORMS...ALONG WITH COOLER AND BREEZY CONDITIONS BEHIND IT
INTO MONDAY.

FOR TONIGHT...SKIES WILL STAY MAINLY CLEAR WITH LOWS MOSTLY IN THE
60S TO AROUND 70 DEGREES. LOW LEVEL SOUTHERLY JET WILL INTENSIFY
OVER THE AREA OVERNIGHT...WITH BREEZY CONDITIONS AT TIMES IN THE
USUAL AREAS FROM NORTHEAST WY THROUGH SOUTHWEST INTO SOUTH CENTRAL
SD. ATMOSPHERE LOOKS TOO DRY TO GET ANY SHOWERS TO DEVELOP WITH THE
JET.

SUNDAY WILL SEE MOSTLY SUNNY TO PARTLY CLOUDY SKIES WITH HIGHS IN
THE 90S TO AROUND 100 DEGREES ON THE PLAINS AS THE THERMAL RIDGE
MOVES ACROSS WESTERN INTO CENTRAL SD DURING THE DAY. EXACT TIMING OF
THE COLD FRONT IS STILL A BIT UNCERTAIN...BUT IT SHOULD MOVE INTO
NORTHEAST WY LATE IN THE DAY AND ACROSS THE REST OF THE FORECAST
AREA SUNDAY NIGHT. WINDS WILL SWITCH TO THE WEST-NORTHWEST AND
BECOME BREEZY TO WINDY ACROSS NORTHWEST INTO WEST CENTRAL SD
OVERNIGHT. EMBEDDED ENERGY IN SOUTHWEST FLOW ALOFT WILL COMBINE WITH
THE FRONT TO PRODUCE AT LEAST ISOLATED SHOWERS AND STORMS OVER A
GOOD PORTION OF THE CWA SUNDAY NIGHT. THE THREAT FOR STRONG TO
SEVERE STORMS IS MINIMAL WITH THE TIMING OF THE FRONT...THOUGH WINDS
COULD GET GUSTY WITH SOME OF THE SHOWERS BEHIND THE FRONT.


.LONG TERM...MONDAY THROUGH SATURDAY
ISSUED AT 258 PM MDT SAT AUG 29 2015

NEGATIVE HEIGHT ANOMALY OVER THE PAC NW WILL REMAIN NEARLY
STATIONARY THROUGH THE PERIOD...WITH GENERALLY WARM CONDS OVER THE
NORTHERN PLAINS AS UPPER LEVEL SW FLOW PERSISTS. THE WESTERN NOAM
UPPER TROUGH WILL GRADUALLY SHIFT EAST AS A STRONGER NORTHERN
STREAM IMPULSE MERGES WITH IT...LEADING TOWARD BREAKDOWN OF THE
PERSISTENT RIDGE. IN THE MEANTIME...ABOVE NORMAL TEMPS WILL
PERSIST THROUGH MOST OF THE PERIOD...WITH MAINLY DRY CONDS. WEAK
COLD FRONT WILL ADVECT THROUGH THE AREA MONDAY MORNING...
SUPPORTING COOLER BUT STILL SEASONAL TEMPS IN A CAA REGIME MONDAY.
CENTRAL NOAM RIDGE WILL RE-SURGE TUE-THUR...WITH VERY WARM CONDS
EXPECTED ONCE AGAIN AS SOUTHERLY FLOW SPREADS OVER THE REGION.
WEAK SW FLOW IMPULSES COULD SUPPORT A FEW ISOLD SHRA/TS IN THE
TUE-WED PERIOD...ESP WITH ANY CONCENTRATED POS THETA-E ADV.
HOWEVER...LACK OF ANY APPRECIABLE SIGNALS PRECLUDE ANY POP
MENTION. NW PAC UPPER TROUGH WILL BIAS EAST BY THE END OF THE WEEK
WITH COOLER WEATHER LOOKING MORE LIKELY WITH INCREASING CHANCES
FOR RAIN.

&&

.AVIATION...FOR THE 18Z TAFS THROUGH 18Z SUNDAY
ISSUED AT 258 PM MDT SAT AUG 29 2015

MAINLY VFR CONDS WITH ISOLD MVFR VIS POSSIBLE IN SMOKE FROM
WESTERN WILDFIRES.

&&

.FIRE WEATHER...
ISSUED AT 258 PM MDT SAT AUG 29 2015

WARM AND DRY CONDS WILL PERSIST ACROSS NE WY. RELATIVE HUMIDITY
ACROSS PORTIONS OF THE NORTHEAST WYOMING PLAINS WILL DROP TO 15
PERCENT OR BELOW THIS AFTERNOON AND AGAIN SUNDAY AFTERNOON. GUSTY
SOUTHWEST WINDS WILL CONTINUE THROUGH SUNDAY...AND ARE EXPECTED TO
BE STRONGEST SUNDAY AFTERNOON AHEAD OF A COLD FRONT. SW WINDS OF
20 TO 30 MPH WITH GUSTS TO AROUND 35 MPH ARE EXPECTED SUN.
PARTIALLY MIXED CONDS CAN BE EXPECTED TONIGHT GIVEN PRESSURE
FALLS...WITH SW WINDS CONTINUING UNDER POOR RH RECOVERY. WENT
AHEAD AND EXTENDED THE RED FLAG WARNING THROUGH SUNDAY AFTERNOON
FOR THIS.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
WY...RED FLAG WARNING UNTIL 8 PM MDT SUNDAY FOR WYZ259-297-298.

&&

$$

SHORT TERM...26
LONG TERM...JC
AVIATION...JC
FIRE WEATHER...JC




000
FXUS63 KUNR 292059
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
259 PM MDT SAT AUG 29 2015

.SHORT TERM...THIS EVENING THROUGH SUNDAY NIGHT
ISSUED AT 258 PM MDT SAT AUG 29 2015

CURRENT SURFACE ANALYSIS SHOWS LOW PRESSURE OVER SK...WITH A COLD
FRONT TRAILING SOUTHWESTWARD INTO NORTHWEST MT AND NORTHERN ID. A
SURFACE TROF EXTENDS SOUTHWARD ACROSS EASTERN MT INTO NORTHEAST
WY. UPPER LEVEL ANALYSIS SHOWS RIDGING OVER THE ROCKIES AND INTO
THE HIGH PLAINS. FLOW ALOFT HAS BECOME WESTERLY OVER THE AREA AND
WILL BECOME SOUTHWESTERLY INTO TONIGHT. TEMPS ARE IN THE 90S
ACROSS THE PLAINS...WITH 80S IN THE BLACK HILLS. WINDS ARE SOUTH
TO SOUTHWEST...BREEZY ACROSS PORTIONS OF NORTHEAST WY. HAZY
SUNSHINE CONTINUES THROUGH THE SMOKE...THOUGH CONDITIONS APPEAR TO
BE GRADUALLY IMPROVING IN MOST AREAS THIS AFTERNOON.

AS RIDGE BUILDS OVER AND EAST OF THE AREA THROUGH THE WEEKEND...HOT
CONDITIONS CAN BE EXPECTED. THE COLD FRONT TO THE NORTHWEST OF THE
REGION WILL EVENTUALLY MAKE IT INTO THE FORECAST AREA LATE SUNDAY
AND SUNDAY NIGHT...BRINGING MOSTLY ISOLATED SHOWERS AND
THUNDERSTORMS...ALONG WITH COOLER AND BREEZY CONDITIONS BEHIND IT
INTO MONDAY.

FOR TONIGHT...SKIES WILL STAY MAINLY CLEAR WITH LOWS MOSTLY IN THE
60S TO AROUND 70 DEGREES. LOW LEVEL SOUTHERLY JET WILL INTENSIFY
OVER THE AREA OVERNIGHT...WITH BREEZY CONDITIONS AT TIMES IN THE
USUAL AREAS FROM NORTHEAST WY THROUGH SOUTHWEST INTO SOUTH CENTRAL
SD. ATMOSPHERE LOOKS TOO DRY TO GET ANY SHOWERS TO DEVELOP WITH THE
JET.

SUNDAY WILL SEE MOSTLY SUNNY TO PARTLY CLOUDY SKIES WITH HIGHS IN
THE 90S TO AROUND 100 DEGREES ON THE PLAINS AS THE THERMAL RIDGE
MOVES ACROSS WESTERN INTO CENTRAL SD DURING THE DAY. EXACT TIMING OF
THE COLD FRONT IS STILL A BIT UNCERTAIN...BUT IT SHOULD MOVE INTO
NORTHEAST WY LATE IN THE DAY AND ACROSS THE REST OF THE FORECAST
AREA SUNDAY NIGHT. WINDS WILL SWITCH TO THE WEST-NORTHWEST AND
BECOME BREEZY TO WINDY ACROSS NORTHWEST INTO WEST CENTRAL SD
OVERNIGHT. EMBEDDED ENERGY IN SOUTHWEST FLOW ALOFT WILL COMBINE WITH
THE FRONT TO PRODUCE AT LEAST ISOLATED SHOWERS AND STORMS OVER A
GOOD PORTION OF THE CWA SUNDAY NIGHT. THE THREAT FOR STRONG TO
SEVERE STORMS IS MINIMAL WITH THE TIMING OF THE FRONT...THOUGH WINDS
COULD GET GUSTY WITH SOME OF THE SHOWERS BEHIND THE FRONT.


.LONG TERM...MONDAY THROUGH SATURDAY
ISSUED AT 258 PM MDT SAT AUG 29 2015

NEGATIVE HEIGHT ANOMALY OVER THE PAC NW WILL REMAIN NEARLY
STATIONARY THROUGH THE PERIOD...WITH GENERALLY WARM CONDS OVER THE
NORTHERN PLAINS AS UPPER LEVEL SW FLOW PERSISTS. THE WESTERN NOAM
UPPER TROUGH WILL GRADUALLY SHIFT EAST AS A STRONGER NORTHERN
STREAM IMPULSE MERGES WITH IT...LEADING TOWARD BREAKDOWN OF THE
PERSISTENT RIDGE. IN THE MEANTIME...ABOVE NORMAL TEMPS WILL
PERSIST THROUGH MOST OF THE PERIOD...WITH MAINLY DRY CONDS. WEAK
COLD FRONT WILL ADVECT THROUGH THE AREA MONDAY MORNING...
SUPPORTING COOLER BUT STILL SEASONAL TEMPS IN A CAA REGIME MONDAY.
CENTRAL NOAM RIDGE WILL RE-SURGE TUE-THUR...WITH VERY WARM CONDS
EXPECTED ONCE AGAIN AS SOUTHERLY FLOW SPREADS OVER THE REGION.
WEAK SW FLOW IMPULSES COULD SUPPORT A FEW ISOLD SHRA/TS IN THE
TUE-WED PERIOD...ESP WITH ANY CONCENTRATED POS THETA-E ADV.
HOWEVER...LACK OF ANY APPRECIABLE SIGNALS PRECLUDE ANY POP
MENTION. NW PAC UPPER TROUGH WILL BIAS EAST BY THE END OF THE WEEK
WITH COOLER WEATHER LOOKING MORE LIKELY WITH INCREASING CHANCES
FOR RAIN.

&&

.AVIATION...FOR THE 18Z TAFS THROUGH 18Z SUNDAY
ISSUED AT 258 PM MDT SAT AUG 29 2015

MAINLY VFR CONDS WITH ISOLD MVFR VIS POSSIBLE IN SMOKE FROM
WESTERN WILDFIRES.

&&

.FIRE WEATHER...
ISSUED AT 258 PM MDT SAT AUG 29 2015

WARM AND DRY CONDS WILL PERSIST ACROSS NE WY. RELATIVE HUMIDITY
ACROSS PORTIONS OF THE NORTHEAST WYOMING PLAINS WILL DROP TO 15
PERCENT OR BELOW THIS AFTERNOON AND AGAIN SUNDAY AFTERNOON. GUSTY
SOUTHWEST WINDS WILL CONTINUE THROUGH SUNDAY...AND ARE EXPECTED TO
BE STRONGEST SUNDAY AFTERNOON AHEAD OF A COLD FRONT. SW WINDS OF
20 TO 30 MPH WITH GUSTS TO AROUND 35 MPH ARE EXPECTED SUN.
PARTIALLY MIXED CONDS CAN BE EXPECTED TONIGHT GIVEN PRESSURE
FALLS...WITH SW WINDS CONTINUING UNDER POOR RH RECOVERY. WENT
AHEAD AND EXTENDED THE RED FLAG WARNING THROUGH SUNDAY AFTERNOON
FOR THIS.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
WY...RED FLAG WARNING UNTIL 8 PM MDT SUNDAY FOR WYZ259-297-298.

&&

$$

SHORT TERM...26
LONG TERM...JC
AVIATION...JC
FIRE WEATHER...JC




000
FXUS65 KRIW 292043
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
243 PM MDT SAT AUG 29 2015

.SHORT TERM...TONIGHT THROUGH SUNDAY NIGHT

HEIGHTS CONTINUE TO LOWER AS AN UPPER LEVEL RIDGE CONTINUES TO
SHIFT SOUTHEAST INTO THE CENTRAL PLAINS AND A DYNAMIC TROUGH
CONTINUES TO APPROACH FROM THE WEST. SOUTHWEST FLOW WILL CONTINUE
TO INCREASE INTO THE EVENING AND WILL REMAIN SPEEDY THROUGH
SUNDAY. AT THE SURFACE...A LEE TROUGH WILL DIG THROUGH THE DAY ON
SUNDAY FURTHER INCREASING THE GRADIENT IN PORTIONS OF CENTRAL AND
EASTERN WYOMING. AT THE SAME TIME...THE COLD FRONT ASSOCIATED
WITH THE PREVIOUSLY MENTIONED TROUGH WILL ADVANCE INTO WESTERN
WYOMING EARLY...DECREASING FIRE DANGER OVER WESTERN ZONES...THEN
IT WILL STALL FOR MUCH OF THE DAY ALLOWING DRY SOUTHWEST FLOW TO
RETURN TO AREAS EAST OF THE DIVIDE...SO THE RED FLAG WARNINGS WERE
EXTENDED IN JOHNSON FREMONT AND NATRONA COUNTIES INTO SUNDAY
EVENING. ALOFT...THE RIGHT ENTRANCE REGION OF A JET STREAK WILL
ENTER THE AREA INCREASING FORCING FOR ASCENT ACROSS MUCH OF THE
STATE...THE LIMITING FACTOR FOR THUNDERSTORMS OF COURSE WILL BE
MOISTURE. THERE ARE INDICATIONS OF SOME MID LEVEL MOISTURE NOSING
NORTH INTO EASTERN SWEETWATER...EASTERN FREMONT...NATRONA AND
SOUTHERN JOHNSON COUNTIES THAT COULD PROVIDE ENOUGH FUEL FOR
SOME VERY DRY AND HIGH BASED STORMS IN THE AFTERNOON. ACROSS
CENTRAL WYOMING...THERE WILL BE A LITTLE LESS MOISTURE AVAILABLE
FOR THUNDERSTORMS BUT THERE COULD BE A STRAY COME OFF OF THE
HIGHER TERRAIN...SO EXPANDED POPS TO ALL AREAS IN THE LATE
AFTERNOON. IN THE WESTERN MOUNTAINS...THERE WILL BE PLENTY OF
MOISTURE AND FORCING ALONG THE STALLED FRONT FOR SCATTERED
THUNDERSTORMS...THOUGH PRECIPITABLE WATER IS A BIT LIMITED SO
EXPECTING A MIX OF WET AND DRY STORMS THERE. RELATIVE HUMIDITY
WILL BE QUITE A BIT HIGHER SO THAT WILL LIMIT FIRE POTENTIAL. THE
COLD FRONT WILL FINALLY GAIN TRACTION AGAIN SUNDAY EVENING AND
WILL FINISH ITS PROGRESSION EASTWARD BY SUNRISE ON MONDAY.

.LONG TERM...MONDAY THROUGH SATURDAY

AGREEMENT AMONG MEDIUM-RANGE FORECAST MODELS IS VERY GOOD THROUGH
THE MIDDLE OF NEXT WEEK. SMALL DIFFERENCES FOR FRIDAY AND SATURDAY
HAVE BECOME BETTER ALIGNED WITH MOST RECENT MODELS RUNS WITH REGARDS
TO THE TRACK AND EVOLUTION OF A PACIFIC NORTHWEST TROUGH THAT WILL
MOVE THROUGH THE INTERMOUNTAIN WEST AND ROCKIES NEXT FRIDAY AND
SATURDAY.

DRIER WESTERLY FLOW WILL COVER THE FORECAST AREA MONDAY IN THE WAKE
OF THE DEPARTING SHORTWAVE TROUGH. SOME WEAK INSTABILITY AND
LINGERING MID-LEVEL MOISTURE NEAR THE COLORADO BORDER IN SWEETWATER
COUNTY DURING THE AFTERNOON AND EVENING. CONVECTION WOULD BE SHORT-
LIVED AND WEAK IF IT CAN MAKE MUCH PROGRESS OFF THE HIGHER TERRAIN
OF NORTHEAST UTAH. OTHERWISE...A DRY MONDAY WITH SEASONAL
TEMPERATURES AND LESS WIND THAT WHAT WILL BE SEEN THIS WEEKEND.
UPPER LEVEL FLOW BEGINS TO BACK TO THE SOUTHWEST ON TUESDAY IN
RESPONSE TO DEEPENING UPPER LEVEL LOW DIGGING INTO THE PACIFIC
NORTHWEST. THERE COULD BE ENOUGH MID-LEVEL MOISTURE TO INITIATE WEAK
MOUNTAIN CONVECTION TUESDAY THROUGH THURSDAY. THEREFORE...HAVE LEFT
LOW PRECIP CHANCES OVER MAINLY THE NORTHWEST MOUNTAINS. BELIEVE THAT
VERY LITTLE RAIN WOULD FALL WITH ANY CONVECTION THAT DEVELOPS AS DEW
POINTS WILL BE LESS THAN 40F AND PRECIPITABLE WATER VALUES LESS THAN
IMPRESSIVE. 700MB TEMPERATURES TUESDAY AND WEDNESDAY WILL AGAIN
APPROACH +15C WHICH WILL HAVE US STARING AT 90F SURFACE
TEMPERATURES. WOULD NOT BE SURPRISED TO SEE MAXIMUM TEMPERATURES
EXCEED 90F...ESPECIALLY ON WEDNESDAY AND MAYBE THURSDAY...DUE TO
INCREASING SOUTHWEST WIND AT THE SURFACE. THE MIDWEEK PATTERN...
BETWEEN TUESDAY AND THURSDAY...IS SHAPING UP TO BE ONE THAT COULD
HAVE CRITICAL FIRE WEATHER IMPLICATIONS. UNSEASONABLY WARM
TEMPERATURES...RELATIVE HUMIDITY IN THE TEENS...AND INCREASING
SOUTHWEST WIND AHEAD OF THE PACIFIC NORTHWEST TROUGH ALL LOOK TO BE
PRESENT ON THESE DAYS. IN FACT...DRIER SURFACE AIR WILL BE ADVECTED
INTO THE STATE FROM THE GREAT BASIN WITH AFTERNOON DEW POINTS
POSSIBLE FALLING TO LESS THAN 30F. THOSE WITH FIRE WEATHER INTERESTS
SHOULD CONTINUE TO MONITOR THE FORECAST FOR POSSIBLE HIGHLIGHTS.
APPROACH OF THE TROUGH WILL LEAD TO A BETTER OPPORTUNITY FOR
CONVECTION ACROSS THE NORTHWEST FRIDAY AFTERNOON AND EVENING. STILL
SOME DISCREPANCIES REGARDING HOW FAR SOUTH THE PACIFIC NORTHWEST
TROUGH WILL DIG AND HOW FAST IT WILL MOVE ACROSS THE FORECAST AREA.
BOTH ISSUES WILL HAVE AN IMPACT ON TEMPERATURES AND SENSIBLE WEATHER
HEADING INTO NEXT WEEKEND. COOLER AIR WILL SLIP SOUTH BEHIND A COLD
FRONT AND COOL THINGS DOWN FOR SATURDAY. FRIDAY TEMPERATURES WILL BE
MORE TRICKY AND DEPENDENT UPON THE TIMING OF THE COLD FRONTAL
PASSAGE. FORECAST FRIDAY TEMPERATURES EAST OF THE CONTINENTAL DIVIDE
COULD END UP BEING TOO COOL...BUT AT THIS RANGE HAVE NOT STRAYED
FROM KEEPING CONSISTENT REGIONAL FORECAST.

&&

.AVIATION.../00Z ISSUANCE/

SOUTH TO SOUTHWEST SFC WINDS 15-25KTS ACROSS MOST AREAS THROUGH
THE TAF PERIOD. ISOLD-WDLY SCT -TSRA PUSHING INTO FAR WEST
WYOMING...SLOWLY EXPECTED TO REACH VCNTY KEVW-KPNA-KCOD LINE 3Z-
6Z SUNDAY. A FEW THUNDERSTORMS WILL LIKELY LINGER INTO SUNDAY
MORNING VCNTY AND WEST OF THE DIVIDE WITH AREAS OF GUSTY S-SW
WINDS CONTINUING AHEAD OF AN APPROACHING COLD FRONT IN MOST AREAS.
HIGH BASED -TSRA WITH GUSTY OUTFLOW WINDS WILL BE MORE LIKELY ON
SUNDAY AFTER 19Z EAST OF THE DIVIDE VCNTY KRKS KCPR...STORMS WILL
BE A BIT LOWER BASED ACROSS WESTERN WYOMING VCNTY KJAC KP60 KPNA
KBPI. EXPECT MOUNTAIN OBSCURATIONS...SOME MOUNTAIN WAVE
ACTIVITY...AND TURBULENCE THROUGH THE PERIOD AS WINDS INCREASE.

FIRE WEATHER...

.RED FLAG WARNING THROUGH SUNDAY FOR PORTIONS OF CENTRAL
WYOMING...

ON SUNDAY...OVERALL IT WILL BE WINDIER THAN IT WAS TODAY BUT WITH
SLIGHTLY HIGHER RELATIVE HUMIDITY. THE COLD FRONT ASSOCIATED WITH
THE TROUGH DIGGING TO THE WEST ADVANCES...IT WILL LIKELY SETTLE
INTO WESTERN...NORTHERN AND SOUTHERN WYOMING FAIRLY EARLY IN THE
DAY...WHICH WOULD END THE FIRE WEATHER THREAT IN THOSE LOCATIONS
ALONG WITH INCREASING CLOUDS AS WELL AS A SLIGHT CHANCE FOR A
WETTING RAIN. LATEST GUIDANCE CONTINUES TO SUGGEST THAT THE FRONT
WILL RETREAT BACK INTO MONTANA DURING THE LATE MORNING...CLEARING
THE WAY FOR MORE STRONG SOUTHWEST FLOW AND LOW HUMIDITY ACROSS
FREMONT...JOHNSON AND NATRONA COUNTIES. SO...THESE AREAS WILL
CONTINUE TO BE UNDER THE RED FLAG WARNING FOR SUNDAY. IN
ADDITION...A SWATH OF MID LEVEL MOISTURE AND CONTINUED INSTABILITY
WILL KICK OF A FEW MIXED WET AND DRY THUNDERSTORMS...SOME OF WHICH
COULD CONTRIBUTE TO NEW FIRE STARTS WITH THE MOST ACTIVITY
EXPECTED ACROSS NORTHERN AND WESTERN WYOMING...WITH A SECONDARY
SWATH EXPECTED OVER NATRONA AND EASTERN FREMONT COUNTIES LATE
SUNDAY AFTERNOON...THE CHANCE OF A WETTING RAIN OUT OF THESE
STORMS IS NEXT TO ZERO. THE BEST CHANCE OF ANY DRY LIGHTNING
STARTS WILL LIKELY BE ON THE PERIPHERY OF ANY THUNDERSTORMS OVER
NATRONA AND JOHNSON COUNTY WHERE THE COMBINATION OF DRIEST
BOUNDARY LEVEL MOISTURE...WIDEST TEMP/DEW POINT SPREADS AND
INSTABILITY WILL LIE ON SUNDAY AFTERNOON.

A REPEAT OF THESE CONDITIONS WILL BE POSSIBLE MID WEEK.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...
RED FLAG WARNING UNTIL 9 PM MDT THIS EVENING FOR WYZ275>277-279-
282-287-414>416.

RED FLAG WARNING UNTIL 9 PM MDT SUNDAY FOR WYZ280-281-283-285-
289-300.

&&

$$

SHORT TERM...ALLEN
LONG TERM...CNJ
AVIATION...ALLEN
FIRE WEATHER...ALLEN



000
FXUS65 KRIW 292043
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
243 PM MDT SAT AUG 29 2015

.SHORT TERM...TONIGHT THROUGH SUNDAY NIGHT

HEIGHTS CONTINUE TO LOWER AS AN UPPER LEVEL RIDGE CONTINUES TO
SHIFT SOUTHEAST INTO THE CENTRAL PLAINS AND A DYNAMIC TROUGH
CONTINUES TO APPROACH FROM THE WEST. SOUTHWEST FLOW WILL CONTINUE
TO INCREASE INTO THE EVENING AND WILL REMAIN SPEEDY THROUGH
SUNDAY. AT THE SURFACE...A LEE TROUGH WILL DIG THROUGH THE DAY ON
SUNDAY FURTHER INCREASING THE GRADIENT IN PORTIONS OF CENTRAL AND
EASTERN WYOMING. AT THE SAME TIME...THE COLD FRONT ASSOCIATED
WITH THE PREVIOUSLY MENTIONED TROUGH WILL ADVANCE INTO WESTERN
WYOMING EARLY...DECREASING FIRE DANGER OVER WESTERN ZONES...THEN
IT WILL STALL FOR MUCH OF THE DAY ALLOWING DRY SOUTHWEST FLOW TO
RETURN TO AREAS EAST OF THE DIVIDE...SO THE RED FLAG WARNINGS WERE
EXTENDED IN JOHNSON FREMONT AND NATRONA COUNTIES INTO SUNDAY
EVENING. ALOFT...THE RIGHT ENTRANCE REGION OF A JET STREAK WILL
ENTER THE AREA INCREASING FORCING FOR ASCENT ACROSS MUCH OF THE
STATE...THE LIMITING FACTOR FOR THUNDERSTORMS OF COURSE WILL BE
MOISTURE. THERE ARE INDICATIONS OF SOME MID LEVEL MOISTURE NOSING
NORTH INTO EASTERN SWEETWATER...EASTERN FREMONT...NATRONA AND
SOUTHERN JOHNSON COUNTIES THAT COULD PROVIDE ENOUGH FUEL FOR
SOME VERY DRY AND HIGH BASED STORMS IN THE AFTERNOON. ACROSS
CENTRAL WYOMING...THERE WILL BE A LITTLE LESS MOISTURE AVAILABLE
FOR THUNDERSTORMS BUT THERE COULD BE A STRAY COME OFF OF THE
HIGHER TERRAIN...SO EXPANDED POPS TO ALL AREAS IN THE LATE
AFTERNOON. IN THE WESTERN MOUNTAINS...THERE WILL BE PLENTY OF
MOISTURE AND FORCING ALONG THE STALLED FRONT FOR SCATTERED
THUNDERSTORMS...THOUGH PRECIPITABLE WATER IS A BIT LIMITED SO
EXPECTING A MIX OF WET AND DRY STORMS THERE. RELATIVE HUMIDITY
WILL BE QUITE A BIT HIGHER SO THAT WILL LIMIT FIRE POTENTIAL. THE
COLD FRONT WILL FINALLY GAIN TRACTION AGAIN SUNDAY EVENING AND
WILL FINISH ITS PROGRESSION EASTWARD BY SUNRISE ON MONDAY.

.LONG TERM...MONDAY THROUGH SATURDAY

AGREEMENT AMONG MEDIUM-RANGE FORECAST MODELS IS VERY GOOD THROUGH
THE MIDDLE OF NEXT WEEK. SMALL DIFFERENCES FOR FRIDAY AND SATURDAY
HAVE BECOME BETTER ALIGNED WITH MOST RECENT MODELS RUNS WITH REGARDS
TO THE TRACK AND EVOLUTION OF A PACIFIC NORTHWEST TROUGH THAT WILL
MOVE THROUGH THE INTERMOUNTAIN WEST AND ROCKIES NEXT FRIDAY AND
SATURDAY.

DRIER WESTERLY FLOW WILL COVER THE FORECAST AREA MONDAY IN THE WAKE
OF THE DEPARTING SHORTWAVE TROUGH. SOME WEAK INSTABILITY AND
LINGERING MID-LEVEL MOISTURE NEAR THE COLORADO BORDER IN SWEETWATER
COUNTY DURING THE AFTERNOON AND EVENING. CONVECTION WOULD BE SHORT-
LIVED AND WEAK IF IT CAN MAKE MUCH PROGRESS OFF THE HIGHER TERRAIN
OF NORTHEAST UTAH. OTHERWISE...A DRY MONDAY WITH SEASONAL
TEMPERATURES AND LESS WIND THAT WHAT WILL BE SEEN THIS WEEKEND.
UPPER LEVEL FLOW BEGINS TO BACK TO THE SOUTHWEST ON TUESDAY IN
RESPONSE TO DEEPENING UPPER LEVEL LOW DIGGING INTO THE PACIFIC
NORTHWEST. THERE COULD BE ENOUGH MID-LEVEL MOISTURE TO INITIATE WEAK
MOUNTAIN CONVECTION TUESDAY THROUGH THURSDAY. THEREFORE...HAVE LEFT
LOW PRECIP CHANCES OVER MAINLY THE NORTHWEST MOUNTAINS. BELIEVE THAT
VERY LITTLE RAIN WOULD FALL WITH ANY CONVECTION THAT DEVELOPS AS DEW
POINTS WILL BE LESS THAN 40F AND PRECIPITABLE WATER VALUES LESS THAN
IMPRESSIVE. 700MB TEMPERATURES TUESDAY AND WEDNESDAY WILL AGAIN
APPROACH +15C WHICH WILL HAVE US STARING AT 90F SURFACE
TEMPERATURES. WOULD NOT BE SURPRISED TO SEE MAXIMUM TEMPERATURES
EXCEED 90F...ESPECIALLY ON WEDNESDAY AND MAYBE THURSDAY...DUE TO
INCREASING SOUTHWEST WIND AT THE SURFACE. THE MIDWEEK PATTERN...
BETWEEN TUESDAY AND THURSDAY...IS SHAPING UP TO BE ONE THAT COULD
HAVE CRITICAL FIRE WEATHER IMPLICATIONS. UNSEASONABLY WARM
TEMPERATURES...RELATIVE HUMIDITY IN THE TEENS...AND INCREASING
SOUTHWEST WIND AHEAD OF THE PACIFIC NORTHWEST TROUGH ALL LOOK TO BE
PRESENT ON THESE DAYS. IN FACT...DRIER SURFACE AIR WILL BE ADVECTED
INTO THE STATE FROM THE GREAT BASIN WITH AFTERNOON DEW POINTS
POSSIBLE FALLING TO LESS THAN 30F. THOSE WITH FIRE WEATHER INTERESTS
SHOULD CONTINUE TO MONITOR THE FORECAST FOR POSSIBLE HIGHLIGHTS.
APPROACH OF THE TROUGH WILL LEAD TO A BETTER OPPORTUNITY FOR
CONVECTION ACROSS THE NORTHWEST FRIDAY AFTERNOON AND EVENING. STILL
SOME DISCREPANCIES REGARDING HOW FAR SOUTH THE PACIFIC NORTHWEST
TROUGH WILL DIG AND HOW FAST IT WILL MOVE ACROSS THE FORECAST AREA.
BOTH ISSUES WILL HAVE AN IMPACT ON TEMPERATURES AND SENSIBLE WEATHER
HEADING INTO NEXT WEEKEND. COOLER AIR WILL SLIP SOUTH BEHIND A COLD
FRONT AND COOL THINGS DOWN FOR SATURDAY. FRIDAY TEMPERATURES WILL BE
MORE TRICKY AND DEPENDENT UPON THE TIMING OF THE COLD FRONTAL
PASSAGE. FORECAST FRIDAY TEMPERATURES EAST OF THE CONTINENTAL DIVIDE
COULD END UP BEING TOO COOL...BUT AT THIS RANGE HAVE NOT STRAYED
FROM KEEPING CONSISTENT REGIONAL FORECAST.

&&

.AVIATION.../00Z ISSUANCE/

SOUTH TO SOUTHWEST SFC WINDS 15-25KTS ACROSS MOST AREAS THROUGH
THE TAF PERIOD. ISOLD-WDLY SCT -TSRA PUSHING INTO FAR WEST
WYOMING...SLOWLY EXPECTED TO REACH VCNTY KEVW-KPNA-KCOD LINE 3Z-
6Z SUNDAY. A FEW THUNDERSTORMS WILL LIKELY LINGER INTO SUNDAY
MORNING VCNTY AND WEST OF THE DIVIDE WITH AREAS OF GUSTY S-SW
WINDS CONTINUING AHEAD OF AN APPROACHING COLD FRONT IN MOST AREAS.
HIGH BASED -TSRA WITH GUSTY OUTFLOW WINDS WILL BE MORE LIKELY ON
SUNDAY AFTER 19Z EAST OF THE DIVIDE VCNTY KRKS KCPR...STORMS WILL
BE A BIT LOWER BASED ACROSS WESTERN WYOMING VCNTY KJAC KP60 KPNA
KBPI. EXPECT MOUNTAIN OBSCURATIONS...SOME MOUNTAIN WAVE
ACTIVITY...AND TURBULENCE THROUGH THE PERIOD AS WINDS INCREASE.

FIRE WEATHER...

.RED FLAG WARNING THROUGH SUNDAY FOR PORTIONS OF CENTRAL
WYOMING...

ON SUNDAY...OVERALL IT WILL BE WINDIER THAN IT WAS TODAY BUT WITH
SLIGHTLY HIGHER RELATIVE HUMIDITY. THE COLD FRONT ASSOCIATED WITH
THE TROUGH DIGGING TO THE WEST ADVANCES...IT WILL LIKELY SETTLE
INTO WESTERN...NORTHERN AND SOUTHERN WYOMING FAIRLY EARLY IN THE
DAY...WHICH WOULD END THE FIRE WEATHER THREAT IN THOSE LOCATIONS
ALONG WITH INCREASING CLOUDS AS WELL AS A SLIGHT CHANCE FOR A
WETTING RAIN. LATEST GUIDANCE CONTINUES TO SUGGEST THAT THE FRONT
WILL RETREAT BACK INTO MONTANA DURING THE LATE MORNING...CLEARING
THE WAY FOR MORE STRONG SOUTHWEST FLOW AND LOW HUMIDITY ACROSS
FREMONT...JOHNSON AND NATRONA COUNTIES. SO...THESE AREAS WILL
CONTINUE TO BE UNDER THE RED FLAG WARNING FOR SUNDAY. IN
ADDITION...A SWATH OF MID LEVEL MOISTURE AND CONTINUED INSTABILITY
WILL KICK OF A FEW MIXED WET AND DRY THUNDERSTORMS...SOME OF WHICH
COULD CONTRIBUTE TO NEW FIRE STARTS WITH THE MOST ACTIVITY
EXPECTED ACROSS NORTHERN AND WESTERN WYOMING...WITH A SECONDARY
SWATH EXPECTED OVER NATRONA AND EASTERN FREMONT COUNTIES LATE
SUNDAY AFTERNOON...THE CHANCE OF A WETTING RAIN OUT OF THESE
STORMS IS NEXT TO ZERO. THE BEST CHANCE OF ANY DRY LIGHTNING
STARTS WILL LIKELY BE ON THE PERIPHERY OF ANY THUNDERSTORMS OVER
NATRONA AND JOHNSON COUNTY WHERE THE COMBINATION OF DRIEST
BOUNDARY LEVEL MOISTURE...WIDEST TEMP/DEW POINT SPREADS AND
INSTABILITY WILL LIE ON SUNDAY AFTERNOON.

A REPEAT OF THESE CONDITIONS WILL BE POSSIBLE MID WEEK.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...
RED FLAG WARNING UNTIL 9 PM MDT THIS EVENING FOR WYZ275>277-279-
282-287-414>416.

RED FLAG WARNING UNTIL 9 PM MDT SUNDAY FOR WYZ280-281-283-285-
289-300.

&&

$$

SHORT TERM...ALLEN
LONG TERM...CNJ
AVIATION...ALLEN
FIRE WEATHER...ALLEN



000
FXUS65 KRIW 292043
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
243 PM MDT SAT AUG 29 2015

.SHORT TERM...TONIGHT THROUGH SUNDAY NIGHT

HEIGHTS CONTINUE TO LOWER AS AN UPPER LEVEL RIDGE CONTINUES TO
SHIFT SOUTHEAST INTO THE CENTRAL PLAINS AND A DYNAMIC TROUGH
CONTINUES TO APPROACH FROM THE WEST. SOUTHWEST FLOW WILL CONTINUE
TO INCREASE INTO THE EVENING AND WILL REMAIN SPEEDY THROUGH
SUNDAY. AT THE SURFACE...A LEE TROUGH WILL DIG THROUGH THE DAY ON
SUNDAY FURTHER INCREASING THE GRADIENT IN PORTIONS OF CENTRAL AND
EASTERN WYOMING. AT THE SAME TIME...THE COLD FRONT ASSOCIATED
WITH THE PREVIOUSLY MENTIONED TROUGH WILL ADVANCE INTO WESTERN
WYOMING EARLY...DECREASING FIRE DANGER OVER WESTERN ZONES...THEN
IT WILL STALL FOR MUCH OF THE DAY ALLOWING DRY SOUTHWEST FLOW TO
RETURN TO AREAS EAST OF THE DIVIDE...SO THE RED FLAG WARNINGS WERE
EXTENDED IN JOHNSON FREMONT AND NATRONA COUNTIES INTO SUNDAY
EVENING. ALOFT...THE RIGHT ENTRANCE REGION OF A JET STREAK WILL
ENTER THE AREA INCREASING FORCING FOR ASCENT ACROSS MUCH OF THE
STATE...THE LIMITING FACTOR FOR THUNDERSTORMS OF COURSE WILL BE
MOISTURE. THERE ARE INDICATIONS OF SOME MID LEVEL MOISTURE NOSING
NORTH INTO EASTERN SWEETWATER...EASTERN FREMONT...NATRONA AND
SOUTHERN JOHNSON COUNTIES THAT COULD PROVIDE ENOUGH FUEL FOR
SOME VERY DRY AND HIGH BASED STORMS IN THE AFTERNOON. ACROSS
CENTRAL WYOMING...THERE WILL BE A LITTLE LESS MOISTURE AVAILABLE
FOR THUNDERSTORMS BUT THERE COULD BE A STRAY COME OFF OF THE
HIGHER TERRAIN...SO EXPANDED POPS TO ALL AREAS IN THE LATE
AFTERNOON. IN THE WESTERN MOUNTAINS...THERE WILL BE PLENTY OF
MOISTURE AND FORCING ALONG THE STALLED FRONT FOR SCATTERED
THUNDERSTORMS...THOUGH PRECIPITABLE WATER IS A BIT LIMITED SO
EXPECTING A MIX OF WET AND DRY STORMS THERE. RELATIVE HUMIDITY
WILL BE QUITE A BIT HIGHER SO THAT WILL LIMIT FIRE POTENTIAL. THE
COLD FRONT WILL FINALLY GAIN TRACTION AGAIN SUNDAY EVENING AND
WILL FINISH ITS PROGRESSION EASTWARD BY SUNRISE ON MONDAY.

.LONG TERM...MONDAY THROUGH SATURDAY

AGREEMENT AMONG MEDIUM-RANGE FORECAST MODELS IS VERY GOOD THROUGH
THE MIDDLE OF NEXT WEEK. SMALL DIFFERENCES FOR FRIDAY AND SATURDAY
HAVE BECOME BETTER ALIGNED WITH MOST RECENT MODELS RUNS WITH REGARDS
TO THE TRACK AND EVOLUTION OF A PACIFIC NORTHWEST TROUGH THAT WILL
MOVE THROUGH THE INTERMOUNTAIN WEST AND ROCKIES NEXT FRIDAY AND
SATURDAY.

DRIER WESTERLY FLOW WILL COVER THE FORECAST AREA MONDAY IN THE WAKE
OF THE DEPARTING SHORTWAVE TROUGH. SOME WEAK INSTABILITY AND
LINGERING MID-LEVEL MOISTURE NEAR THE COLORADO BORDER IN SWEETWATER
COUNTY DURING THE AFTERNOON AND EVENING. CONVECTION WOULD BE SHORT-
LIVED AND WEAK IF IT CAN MAKE MUCH PROGRESS OFF THE HIGHER TERRAIN
OF NORTHEAST UTAH. OTHERWISE...A DRY MONDAY WITH SEASONAL
TEMPERATURES AND LESS WIND THAT WHAT WILL BE SEEN THIS WEEKEND.
UPPER LEVEL FLOW BEGINS TO BACK TO THE SOUTHWEST ON TUESDAY IN
RESPONSE TO DEEPENING UPPER LEVEL LOW DIGGING INTO THE PACIFIC
NORTHWEST. THERE COULD BE ENOUGH MID-LEVEL MOISTURE TO INITIATE WEAK
MOUNTAIN CONVECTION TUESDAY THROUGH THURSDAY. THEREFORE...HAVE LEFT
LOW PRECIP CHANCES OVER MAINLY THE NORTHWEST MOUNTAINS. BELIEVE THAT
VERY LITTLE RAIN WOULD FALL WITH ANY CONVECTION THAT DEVELOPS AS DEW
POINTS WILL BE LESS THAN 40F AND PRECIPITABLE WATER VALUES LESS THAN
IMPRESSIVE. 700MB TEMPERATURES TUESDAY AND WEDNESDAY WILL AGAIN
APPROACH +15C WHICH WILL HAVE US STARING AT 90F SURFACE
TEMPERATURES. WOULD NOT BE SURPRISED TO SEE MAXIMUM TEMPERATURES
EXCEED 90F...ESPECIALLY ON WEDNESDAY AND MAYBE THURSDAY...DUE TO
INCREASING SOUTHWEST WIND AT THE SURFACE. THE MIDWEEK PATTERN...
BETWEEN TUESDAY AND THURSDAY...IS SHAPING UP TO BE ONE THAT COULD
HAVE CRITICAL FIRE WEATHER IMPLICATIONS. UNSEASONABLY WARM
TEMPERATURES...RELATIVE HUMIDITY IN THE TEENS...AND INCREASING
SOUTHWEST WIND AHEAD OF THE PACIFIC NORTHWEST TROUGH ALL LOOK TO BE
PRESENT ON THESE DAYS. IN FACT...DRIER SURFACE AIR WILL BE ADVECTED
INTO THE STATE FROM THE GREAT BASIN WITH AFTERNOON DEW POINTS
POSSIBLE FALLING TO LESS THAN 30F. THOSE WITH FIRE WEATHER INTERESTS
SHOULD CONTINUE TO MONITOR THE FORECAST FOR POSSIBLE HIGHLIGHTS.
APPROACH OF THE TROUGH WILL LEAD TO A BETTER OPPORTUNITY FOR
CONVECTION ACROSS THE NORTHWEST FRIDAY AFTERNOON AND EVENING. STILL
SOME DISCREPANCIES REGARDING HOW FAR SOUTH THE PACIFIC NORTHWEST
TROUGH WILL DIG AND HOW FAST IT WILL MOVE ACROSS THE FORECAST AREA.
BOTH ISSUES WILL HAVE AN IMPACT ON TEMPERATURES AND SENSIBLE WEATHER
HEADING INTO NEXT WEEKEND. COOLER AIR WILL SLIP SOUTH BEHIND A COLD
FRONT AND COOL THINGS DOWN FOR SATURDAY. FRIDAY TEMPERATURES WILL BE
MORE TRICKY AND DEPENDENT UPON THE TIMING OF THE COLD FRONTAL
PASSAGE. FORECAST FRIDAY TEMPERATURES EAST OF THE CONTINENTAL DIVIDE
COULD END UP BEING TOO COOL...BUT AT THIS RANGE HAVE NOT STRAYED
FROM KEEPING CONSISTENT REGIONAL FORECAST.

&&

.AVIATION.../00Z ISSUANCE/

SOUTH TO SOUTHWEST SFC WINDS 15-25KTS ACROSS MOST AREAS THROUGH
THE TAF PERIOD. ISOLD-WDLY SCT -TSRA PUSHING INTO FAR WEST
WYOMING...SLOWLY EXPECTED TO REACH VCNTY KEVW-KPNA-KCOD LINE 3Z-
6Z SUNDAY. A FEW THUNDERSTORMS WILL LIKELY LINGER INTO SUNDAY
MORNING VCNTY AND WEST OF THE DIVIDE WITH AREAS OF GUSTY S-SW
WINDS CONTINUING AHEAD OF AN APPROACHING COLD FRONT IN MOST AREAS.
HIGH BASED -TSRA WITH GUSTY OUTFLOW WINDS WILL BE MORE LIKELY ON
SUNDAY AFTER 19Z EAST OF THE DIVIDE VCNTY KRKS KCPR...STORMS WILL
BE A BIT LOWER BASED ACROSS WESTERN WYOMING VCNTY KJAC KP60 KPNA
KBPI. EXPECT MOUNTAIN OBSCURATIONS...SOME MOUNTAIN WAVE
ACTIVITY...AND TURBULENCE THROUGH THE PERIOD AS WINDS INCREASE.

FIRE WEATHER...

.RED FLAG WARNING THROUGH SUNDAY FOR PORTIONS OF CENTRAL
WYOMING...

ON SUNDAY...OVERALL IT WILL BE WINDIER THAN IT WAS TODAY BUT WITH
SLIGHTLY HIGHER RELATIVE HUMIDITY. THE COLD FRONT ASSOCIATED WITH
THE TROUGH DIGGING TO THE WEST ADVANCES...IT WILL LIKELY SETTLE
INTO WESTERN...NORTHERN AND SOUTHERN WYOMING FAIRLY EARLY IN THE
DAY...WHICH WOULD END THE FIRE WEATHER THREAT IN THOSE LOCATIONS
ALONG WITH INCREASING CLOUDS AS WELL AS A SLIGHT CHANCE FOR A
WETTING RAIN. LATEST GUIDANCE CONTINUES TO SUGGEST THAT THE FRONT
WILL RETREAT BACK INTO MONTANA DURING THE LATE MORNING...CLEARING
THE WAY FOR MORE STRONG SOUTHWEST FLOW AND LOW HUMIDITY ACROSS
FREMONT...JOHNSON AND NATRONA COUNTIES. SO...THESE AREAS WILL
CONTINUE TO BE UNDER THE RED FLAG WARNING FOR SUNDAY. IN
ADDITION...A SWATH OF MID LEVEL MOISTURE AND CONTINUED INSTABILITY
WILL KICK OF A FEW MIXED WET AND DRY THUNDERSTORMS...SOME OF WHICH
COULD CONTRIBUTE TO NEW FIRE STARTS WITH THE MOST ACTIVITY
EXPECTED ACROSS NORTHERN AND WESTERN WYOMING...WITH A SECONDARY
SWATH EXPECTED OVER NATRONA AND EASTERN FREMONT COUNTIES LATE
SUNDAY AFTERNOON...THE CHANCE OF A WETTING RAIN OUT OF THESE
STORMS IS NEXT TO ZERO. THE BEST CHANCE OF ANY DRY LIGHTNING
STARTS WILL LIKELY BE ON THE PERIPHERY OF ANY THUNDERSTORMS OVER
NATRONA AND JOHNSON COUNTY WHERE THE COMBINATION OF DRIEST
BOUNDARY LEVEL MOISTURE...WIDEST TEMP/DEW POINT SPREADS AND
INSTABILITY WILL LIE ON SUNDAY AFTERNOON.

A REPEAT OF THESE CONDITIONS WILL BE POSSIBLE MID WEEK.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...
RED FLAG WARNING UNTIL 9 PM MDT THIS EVENING FOR WYZ275>277-279-
282-287-414>416.

RED FLAG WARNING UNTIL 9 PM MDT SUNDAY FOR WYZ280-281-283-285-
289-300.

&&

$$

SHORT TERM...ALLEN
LONG TERM...CNJ
AVIATION...ALLEN
FIRE WEATHER...ALLEN



000
FXUS65 KRIW 292043
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
243 PM MDT SAT AUG 29 2015

.SHORT TERM...TONIGHT THROUGH SUNDAY NIGHT

HEIGHTS CONTINUE TO LOWER AS AN UPPER LEVEL RIDGE CONTINUES TO
SHIFT SOUTHEAST INTO THE CENTRAL PLAINS AND A DYNAMIC TROUGH
CONTINUES TO APPROACH FROM THE WEST. SOUTHWEST FLOW WILL CONTINUE
TO INCREASE INTO THE EVENING AND WILL REMAIN SPEEDY THROUGH
SUNDAY. AT THE SURFACE...A LEE TROUGH WILL DIG THROUGH THE DAY ON
SUNDAY FURTHER INCREASING THE GRADIENT IN PORTIONS OF CENTRAL AND
EASTERN WYOMING. AT THE SAME TIME...THE COLD FRONT ASSOCIATED
WITH THE PREVIOUSLY MENTIONED TROUGH WILL ADVANCE INTO WESTERN
WYOMING EARLY...DECREASING FIRE DANGER OVER WESTERN ZONES...THEN
IT WILL STALL FOR MUCH OF THE DAY ALLOWING DRY SOUTHWEST FLOW TO
RETURN TO AREAS EAST OF THE DIVIDE...SO THE RED FLAG WARNINGS WERE
EXTENDED IN JOHNSON FREMONT AND NATRONA COUNTIES INTO SUNDAY
EVENING. ALOFT...THE RIGHT ENTRANCE REGION OF A JET STREAK WILL
ENTER THE AREA INCREASING FORCING FOR ASCENT ACROSS MUCH OF THE
STATE...THE LIMITING FACTOR FOR THUNDERSTORMS OF COURSE WILL BE
MOISTURE. THERE ARE INDICATIONS OF SOME MID LEVEL MOISTURE NOSING
NORTH INTO EASTERN SWEETWATER...EASTERN FREMONT...NATRONA AND
SOUTHERN JOHNSON COUNTIES THAT COULD PROVIDE ENOUGH FUEL FOR
SOME VERY DRY AND HIGH BASED STORMS IN THE AFTERNOON. ACROSS
CENTRAL WYOMING...THERE WILL BE A LITTLE LESS MOISTURE AVAILABLE
FOR THUNDERSTORMS BUT THERE COULD BE A STRAY COME OFF OF THE
HIGHER TERRAIN...SO EXPANDED POPS TO ALL AREAS IN THE LATE
AFTERNOON. IN THE WESTERN MOUNTAINS...THERE WILL BE PLENTY OF
MOISTURE AND FORCING ALONG THE STALLED FRONT FOR SCATTERED
THUNDERSTORMS...THOUGH PRECIPITABLE WATER IS A BIT LIMITED SO
EXPECTING A MIX OF WET AND DRY STORMS THERE. RELATIVE HUMIDITY
WILL BE QUITE A BIT HIGHER SO THAT WILL LIMIT FIRE POTENTIAL. THE
COLD FRONT WILL FINALLY GAIN TRACTION AGAIN SUNDAY EVENING AND
WILL FINISH ITS PROGRESSION EASTWARD BY SUNRISE ON MONDAY.

.LONG TERM...MONDAY THROUGH SATURDAY

AGREEMENT AMONG MEDIUM-RANGE FORECAST MODELS IS VERY GOOD THROUGH
THE MIDDLE OF NEXT WEEK. SMALL DIFFERENCES FOR FRIDAY AND SATURDAY
HAVE BECOME BETTER ALIGNED WITH MOST RECENT MODELS RUNS WITH REGARDS
TO THE TRACK AND EVOLUTION OF A PACIFIC NORTHWEST TROUGH THAT WILL
MOVE THROUGH THE INTERMOUNTAIN WEST AND ROCKIES NEXT FRIDAY AND
SATURDAY.

DRIER WESTERLY FLOW WILL COVER THE FORECAST AREA MONDAY IN THE WAKE
OF THE DEPARTING SHORTWAVE TROUGH. SOME WEAK INSTABILITY AND
LINGERING MID-LEVEL MOISTURE NEAR THE COLORADO BORDER IN SWEETWATER
COUNTY DURING THE AFTERNOON AND EVENING. CONVECTION WOULD BE SHORT-
LIVED AND WEAK IF IT CAN MAKE MUCH PROGRESS OFF THE HIGHER TERRAIN
OF NORTHEAST UTAH. OTHERWISE...A DRY MONDAY WITH SEASONAL
TEMPERATURES AND LESS WIND THAT WHAT WILL BE SEEN THIS WEEKEND.
UPPER LEVEL FLOW BEGINS TO BACK TO THE SOUTHWEST ON TUESDAY IN
RESPONSE TO DEEPENING UPPER LEVEL LOW DIGGING INTO THE PACIFIC
NORTHWEST. THERE COULD BE ENOUGH MID-LEVEL MOISTURE TO INITIATE WEAK
MOUNTAIN CONVECTION TUESDAY THROUGH THURSDAY. THEREFORE...HAVE LEFT
LOW PRECIP CHANCES OVER MAINLY THE NORTHWEST MOUNTAINS. BELIEVE THAT
VERY LITTLE RAIN WOULD FALL WITH ANY CONVECTION THAT DEVELOPS AS DEW
POINTS WILL BE LESS THAN 40F AND PRECIPITABLE WATER VALUES LESS THAN
IMPRESSIVE. 700MB TEMPERATURES TUESDAY AND WEDNESDAY WILL AGAIN
APPROACH +15C WHICH WILL HAVE US STARING AT 90F SURFACE
TEMPERATURES. WOULD NOT BE SURPRISED TO SEE MAXIMUM TEMPERATURES
EXCEED 90F...ESPECIALLY ON WEDNESDAY AND MAYBE THURSDAY...DUE TO
INCREASING SOUTHWEST WIND AT THE SURFACE. THE MIDWEEK PATTERN...
BETWEEN TUESDAY AND THURSDAY...IS SHAPING UP TO BE ONE THAT COULD
HAVE CRITICAL FIRE WEATHER IMPLICATIONS. UNSEASONABLY WARM
TEMPERATURES...RELATIVE HUMIDITY IN THE TEENS...AND INCREASING
SOUTHWEST WIND AHEAD OF THE PACIFIC NORTHWEST TROUGH ALL LOOK TO BE
PRESENT ON THESE DAYS. IN FACT...DRIER SURFACE AIR WILL BE ADVECTED
INTO THE STATE FROM THE GREAT BASIN WITH AFTERNOON DEW POINTS
POSSIBLE FALLING TO LESS THAN 30F. THOSE WITH FIRE WEATHER INTERESTS
SHOULD CONTINUE TO MONITOR THE FORECAST FOR POSSIBLE HIGHLIGHTS.
APPROACH OF THE TROUGH WILL LEAD TO A BETTER OPPORTUNITY FOR
CONVECTION ACROSS THE NORTHWEST FRIDAY AFTERNOON AND EVENING. STILL
SOME DISCREPANCIES REGARDING HOW FAR SOUTH THE PACIFIC NORTHWEST
TROUGH WILL DIG AND HOW FAST IT WILL MOVE ACROSS THE FORECAST AREA.
BOTH ISSUES WILL HAVE AN IMPACT ON TEMPERATURES AND SENSIBLE WEATHER
HEADING INTO NEXT WEEKEND. COOLER AIR WILL SLIP SOUTH BEHIND A COLD
FRONT AND COOL THINGS DOWN FOR SATURDAY. FRIDAY TEMPERATURES WILL BE
MORE TRICKY AND DEPENDENT UPON THE TIMING OF THE COLD FRONTAL
PASSAGE. FORECAST FRIDAY TEMPERATURES EAST OF THE CONTINENTAL DIVIDE
COULD END UP BEING TOO COOL...BUT AT THIS RANGE HAVE NOT STRAYED
FROM KEEPING CONSISTENT REGIONAL FORECAST.

&&

.AVIATION.../00Z ISSUANCE/

SOUTH TO SOUTHWEST SFC WINDS 15-25KTS ACROSS MOST AREAS THROUGH
THE TAF PERIOD. ISOLD-WDLY SCT -TSRA PUSHING INTO FAR WEST
WYOMING...SLOWLY EXPECTED TO REACH VCNTY KEVW-KPNA-KCOD LINE 3Z-
6Z SUNDAY. A FEW THUNDERSTORMS WILL LIKELY LINGER INTO SUNDAY
MORNING VCNTY AND WEST OF THE DIVIDE WITH AREAS OF GUSTY S-SW
WINDS CONTINUING AHEAD OF AN APPROACHING COLD FRONT IN MOST AREAS.
HIGH BASED -TSRA WITH GUSTY OUTFLOW WINDS WILL BE MORE LIKELY ON
SUNDAY AFTER 19Z EAST OF THE DIVIDE VCNTY KRKS KCPR...STORMS WILL
BE A BIT LOWER BASED ACROSS WESTERN WYOMING VCNTY KJAC KP60 KPNA
KBPI. EXPECT MOUNTAIN OBSCURATIONS...SOME MOUNTAIN WAVE
ACTIVITY...AND TURBULENCE THROUGH THE PERIOD AS WINDS INCREASE.

FIRE WEATHER...

.RED FLAG WARNING THROUGH SUNDAY FOR PORTIONS OF CENTRAL
WYOMING...

ON SUNDAY...OVERALL IT WILL BE WINDIER THAN IT WAS TODAY BUT WITH
SLIGHTLY HIGHER RELATIVE HUMIDITY. THE COLD FRONT ASSOCIATED WITH
THE TROUGH DIGGING TO THE WEST ADVANCES...IT WILL LIKELY SETTLE
INTO WESTERN...NORTHERN AND SOUTHERN WYOMING FAIRLY EARLY IN THE
DAY...WHICH WOULD END THE FIRE WEATHER THREAT IN THOSE LOCATIONS
ALONG WITH INCREASING CLOUDS AS WELL AS A SLIGHT CHANCE FOR A
WETTING RAIN. LATEST GUIDANCE CONTINUES TO SUGGEST THAT THE FRONT
WILL RETREAT BACK INTO MONTANA DURING THE LATE MORNING...CLEARING
THE WAY FOR MORE STRONG SOUTHWEST FLOW AND LOW HUMIDITY ACROSS
FREMONT...JOHNSON AND NATRONA COUNTIES. SO...THESE AREAS WILL
CONTINUE TO BE UNDER THE RED FLAG WARNING FOR SUNDAY. IN
ADDITION...A SWATH OF MID LEVEL MOISTURE AND CONTINUED INSTABILITY
WILL KICK OF A FEW MIXED WET AND DRY THUNDERSTORMS...SOME OF WHICH
COULD CONTRIBUTE TO NEW FIRE STARTS WITH THE MOST ACTIVITY
EXPECTED ACROSS NORTHERN AND WESTERN WYOMING...WITH A SECONDARY
SWATH EXPECTED OVER NATRONA AND EASTERN FREMONT COUNTIES LATE
SUNDAY AFTERNOON...THE CHANCE OF A WETTING RAIN OUT OF THESE
STORMS IS NEXT TO ZERO. THE BEST CHANCE OF ANY DRY LIGHTNING
STARTS WILL LIKELY BE ON THE PERIPHERY OF ANY THUNDERSTORMS OVER
NATRONA AND JOHNSON COUNTY WHERE THE COMBINATION OF DRIEST
BOUNDARY LEVEL MOISTURE...WIDEST TEMP/DEW POINT SPREADS AND
INSTABILITY WILL LIE ON SUNDAY AFTERNOON.

A REPEAT OF THESE CONDITIONS WILL BE POSSIBLE MID WEEK.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...
RED FLAG WARNING UNTIL 9 PM MDT THIS EVENING FOR WYZ275>277-279-
282-287-414>416.

RED FLAG WARNING UNTIL 9 PM MDT SUNDAY FOR WYZ280-281-283-285-
289-300.

&&

$$

SHORT TERM...ALLEN
LONG TERM...CNJ
AVIATION...ALLEN
FIRE WEATHER...ALLEN



000
FXUS65 KRIW 292043
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
243 PM MDT SAT AUG 29 2015

.SHORT TERM...TONIGHT THROUGH SUNDAY NIGHT

HEIGHTS CONTINUE TO LOWER AS AN UPPER LEVEL RIDGE CONTINUES TO
SHIFT SOUTHEAST INTO THE CENTRAL PLAINS AND A DYNAMIC TROUGH
CONTINUES TO APPROACH FROM THE WEST. SOUTHWEST FLOW WILL CONTINUE
TO INCREASE INTO THE EVENING AND WILL REMAIN SPEEDY THROUGH
SUNDAY. AT THE SURFACE...A LEE TROUGH WILL DIG THROUGH THE DAY ON
SUNDAY FURTHER INCREASING THE GRADIENT IN PORTIONS OF CENTRAL AND
EASTERN WYOMING. AT THE SAME TIME...THE COLD FRONT ASSOCIATED
WITH THE PREVIOUSLY MENTIONED TROUGH WILL ADVANCE INTO WESTERN
WYOMING EARLY...DECREASING FIRE DANGER OVER WESTERN ZONES...THEN
IT WILL STALL FOR MUCH OF THE DAY ALLOWING DRY SOUTHWEST FLOW TO
RETURN TO AREAS EAST OF THE DIVIDE...SO THE RED FLAG WARNINGS WERE
EXTENDED IN JOHNSON FREMONT AND NATRONA COUNTIES INTO SUNDAY
EVENING. ALOFT...THE RIGHT ENTRANCE REGION OF A JET STREAK WILL
ENTER THE AREA INCREASING FORCING FOR ASCENT ACROSS MUCH OF THE
STATE...THE LIMITING FACTOR FOR THUNDERSTORMS OF COURSE WILL BE
MOISTURE. THERE ARE INDICATIONS OF SOME MID LEVEL MOISTURE NOSING
NORTH INTO EASTERN SWEETWATER...EASTERN FREMONT...NATRONA AND
SOUTHERN JOHNSON COUNTIES THAT COULD PROVIDE ENOUGH FUEL FOR
SOME VERY DRY AND HIGH BASED STORMS IN THE AFTERNOON. ACROSS
CENTRAL WYOMING...THERE WILL BE A LITTLE LESS MOISTURE AVAILABLE
FOR THUNDERSTORMS BUT THERE COULD BE A STRAY COME OFF OF THE
HIGHER TERRAIN...SO EXPANDED POPS TO ALL AREAS IN THE LATE
AFTERNOON. IN THE WESTERN MOUNTAINS...THERE WILL BE PLENTY OF
MOISTURE AND FORCING ALONG THE STALLED FRONT FOR SCATTERED
THUNDERSTORMS...THOUGH PRECIPITABLE WATER IS A BIT LIMITED SO
EXPECTING A MIX OF WET AND DRY STORMS THERE. RELATIVE HUMIDITY
WILL BE QUITE A BIT HIGHER SO THAT WILL LIMIT FIRE POTENTIAL. THE
COLD FRONT WILL FINALLY GAIN TRACTION AGAIN SUNDAY EVENING AND
WILL FINISH ITS PROGRESSION EASTWARD BY SUNRISE ON MONDAY.

.LONG TERM...MONDAY THROUGH SATURDAY

AGREEMENT AMONG MEDIUM-RANGE FORECAST MODELS IS VERY GOOD THROUGH
THE MIDDLE OF NEXT WEEK. SMALL DIFFERENCES FOR FRIDAY AND SATURDAY
HAVE BECOME BETTER ALIGNED WITH MOST RECENT MODELS RUNS WITH REGARDS
TO THE TRACK AND EVOLUTION OF A PACIFIC NORTHWEST TROUGH THAT WILL
MOVE THROUGH THE INTERMOUNTAIN WEST AND ROCKIES NEXT FRIDAY AND
SATURDAY.

DRIER WESTERLY FLOW WILL COVER THE FORECAST AREA MONDAY IN THE WAKE
OF THE DEPARTING SHORTWAVE TROUGH. SOME WEAK INSTABILITY AND
LINGERING MID-LEVEL MOISTURE NEAR THE COLORADO BORDER IN SWEETWATER
COUNTY DURING THE AFTERNOON AND EVENING. CONVECTION WOULD BE SHORT-
LIVED AND WEAK IF IT CAN MAKE MUCH PROGRESS OFF THE HIGHER TERRAIN
OF NORTHEAST UTAH. OTHERWISE...A DRY MONDAY WITH SEASONAL
TEMPERATURES AND LESS WIND THAT WHAT WILL BE SEEN THIS WEEKEND.
UPPER LEVEL FLOW BEGINS TO BACK TO THE SOUTHWEST ON TUESDAY IN
RESPONSE TO DEEPENING UPPER LEVEL LOW DIGGING INTO THE PACIFIC
NORTHWEST. THERE COULD BE ENOUGH MID-LEVEL MOISTURE TO INITIATE WEAK
MOUNTAIN CONVECTION TUESDAY THROUGH THURSDAY. THEREFORE...HAVE LEFT
LOW PRECIP CHANCES OVER MAINLY THE NORTHWEST MOUNTAINS. BELIEVE THAT
VERY LITTLE RAIN WOULD FALL WITH ANY CONVECTION THAT DEVELOPS AS DEW
POINTS WILL BE LESS THAN 40F AND PRECIPITABLE WATER VALUES LESS THAN
IMPRESSIVE. 700MB TEMPERATURES TUESDAY AND WEDNESDAY WILL AGAIN
APPROACH +15C WHICH WILL HAVE US STARING AT 90F SURFACE
TEMPERATURES. WOULD NOT BE SURPRISED TO SEE MAXIMUM TEMPERATURES
EXCEED 90F...ESPECIALLY ON WEDNESDAY AND MAYBE THURSDAY...DUE TO
INCREASING SOUTHWEST WIND AT THE SURFACE. THE MIDWEEK PATTERN...
BETWEEN TUESDAY AND THURSDAY...IS SHAPING UP TO BE ONE THAT COULD
HAVE CRITICAL FIRE WEATHER IMPLICATIONS. UNSEASONABLY WARM
TEMPERATURES...RELATIVE HUMIDITY IN THE TEENS...AND INCREASING
SOUTHWEST WIND AHEAD OF THE PACIFIC NORTHWEST TROUGH ALL LOOK TO BE
PRESENT ON THESE DAYS. IN FACT...DRIER SURFACE AIR WILL BE ADVECTED
INTO THE STATE FROM THE GREAT BASIN WITH AFTERNOON DEW POINTS
POSSIBLE FALLING TO LESS THAN 30F. THOSE WITH FIRE WEATHER INTERESTS
SHOULD CONTINUE TO MONITOR THE FORECAST FOR POSSIBLE HIGHLIGHTS.
APPROACH OF THE TROUGH WILL LEAD TO A BETTER OPPORTUNITY FOR
CONVECTION ACROSS THE NORTHWEST FRIDAY AFTERNOON AND EVENING. STILL
SOME DISCREPANCIES REGARDING HOW FAR SOUTH THE PACIFIC NORTHWEST
TROUGH WILL DIG AND HOW FAST IT WILL MOVE ACROSS THE FORECAST AREA.
BOTH ISSUES WILL HAVE AN IMPACT ON TEMPERATURES AND SENSIBLE WEATHER
HEADING INTO NEXT WEEKEND. COOLER AIR WILL SLIP SOUTH BEHIND A COLD
FRONT AND COOL THINGS DOWN FOR SATURDAY. FRIDAY TEMPERATURES WILL BE
MORE TRICKY AND DEPENDENT UPON THE TIMING OF THE COLD FRONTAL
PASSAGE. FORECAST FRIDAY TEMPERATURES EAST OF THE CONTINENTAL DIVIDE
COULD END UP BEING TOO COOL...BUT AT THIS RANGE HAVE NOT STRAYED
FROM KEEPING CONSISTENT REGIONAL FORECAST.

&&

.AVIATION.../00Z ISSUANCE/

SOUTH TO SOUTHWEST SFC WINDS 15-25KTS ACROSS MOST AREAS THROUGH
THE TAF PERIOD. ISOLD-WDLY SCT -TSRA PUSHING INTO FAR WEST
WYOMING...SLOWLY EXPECTED TO REACH VCNTY KEVW-KPNA-KCOD LINE 3Z-
6Z SUNDAY. A FEW THUNDERSTORMS WILL LIKELY LINGER INTO SUNDAY
MORNING VCNTY AND WEST OF THE DIVIDE WITH AREAS OF GUSTY S-SW
WINDS CONTINUING AHEAD OF AN APPROACHING COLD FRONT IN MOST AREAS.
HIGH BASED -TSRA WITH GUSTY OUTFLOW WINDS WILL BE MORE LIKELY ON
SUNDAY AFTER 19Z EAST OF THE DIVIDE VCNTY KRKS KCPR...STORMS WILL
BE A BIT LOWER BASED ACROSS WESTERN WYOMING VCNTY KJAC KP60 KPNA
KBPI. EXPECT MOUNTAIN OBSCURATIONS...SOME MOUNTAIN WAVE
ACTIVITY...AND TURBULENCE THROUGH THE PERIOD AS WINDS INCREASE.

FIRE WEATHER...

.RED FLAG WARNING THROUGH SUNDAY FOR PORTIONS OF CENTRAL
WYOMING...

ON SUNDAY...OVERALL IT WILL BE WINDIER THAN IT WAS TODAY BUT WITH
SLIGHTLY HIGHER RELATIVE HUMIDITY. THE COLD FRONT ASSOCIATED WITH
THE TROUGH DIGGING TO THE WEST ADVANCES...IT WILL LIKELY SETTLE
INTO WESTERN...NORTHERN AND SOUTHERN WYOMING FAIRLY EARLY IN THE
DAY...WHICH WOULD END THE FIRE WEATHER THREAT IN THOSE LOCATIONS
ALONG WITH INCREASING CLOUDS AS WELL AS A SLIGHT CHANCE FOR A
WETTING RAIN. LATEST GUIDANCE CONTINUES TO SUGGEST THAT THE FRONT
WILL RETREAT BACK INTO MONTANA DURING THE LATE MORNING...CLEARING
THE WAY FOR MORE STRONG SOUTHWEST FLOW AND LOW HUMIDITY ACROSS
FREMONT...JOHNSON AND NATRONA COUNTIES. SO...THESE AREAS WILL
CONTINUE TO BE UNDER THE RED FLAG WARNING FOR SUNDAY. IN
ADDITION...A SWATH OF MID LEVEL MOISTURE AND CONTINUED INSTABILITY
WILL KICK OF A FEW MIXED WET AND DRY THUNDERSTORMS...SOME OF WHICH
COULD CONTRIBUTE TO NEW FIRE STARTS WITH THE MOST ACTIVITY
EXPECTED ACROSS NORTHERN AND WESTERN WYOMING...WITH A SECONDARY
SWATH EXPECTED OVER NATRONA AND EASTERN FREMONT COUNTIES LATE
SUNDAY AFTERNOON...THE CHANCE OF A WETTING RAIN OUT OF THESE
STORMS IS NEXT TO ZERO. THE BEST CHANCE OF ANY DRY LIGHTNING
STARTS WILL LIKELY BE ON THE PERIPHERY OF ANY THUNDERSTORMS OVER
NATRONA AND JOHNSON COUNTY WHERE THE COMBINATION OF DRIEST
BOUNDARY LEVEL MOISTURE...WIDEST TEMP/DEW POINT SPREADS AND
INSTABILITY WILL LIE ON SUNDAY AFTERNOON.

A REPEAT OF THESE CONDITIONS WILL BE POSSIBLE MID WEEK.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...
RED FLAG WARNING UNTIL 9 PM MDT THIS EVENING FOR WYZ275>277-279-
282-287-414>416.

RED FLAG WARNING UNTIL 9 PM MDT SUNDAY FOR WYZ280-281-283-285-
289-300.

&&

$$

SHORT TERM...ALLEN
LONG TERM...CNJ
AVIATION...ALLEN
FIRE WEATHER...ALLEN



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