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000
FXUS63 KUNR 291553
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
953 AM MDT FRI AUG 29 2014

.UPDATE...
ISSUED AT 952 AM MDT FRI AUG 29 2014

CURRENT SURFACE ANALYSIS SHOWS LOW PRESSURE OVER NORTHEAST
SD...WITH COOL FRONT STRETCHING SOUTHWESTWARD ACROSS SD INTO
CENTRAL WY. UPPER LEVEL ANALYSIS SHOWS SLOW MOVING LOW OVER
SOUTHEAST NEB...WITH SHORTWAVE ENERGY BEHIND IT MOVING ACROSS THE
NORTHERN HIGH PLAINS. KUDX RADAR SHOWS ISOLATED TO SCATTERED
SHOWERS FROM FAR NORTHWEST SD THROUGH THE BLACK HILLS AND ACROSS
FAR EASTERN WY. A COUPLE OF LIGHTNING STRIKES HAVE BEEN NOTED WITH
THE ACTIVITY SO FAR. WINDS HAVE BEEN GUSTY ACROSS PARTS OF THE SD
PLAINS BEHIND THE FRONT...ESPECIALLY IN THE RAPID CITY AREA. WINDS
WILL GRADUALLY DIMINISH INTO THE AFTERNOON. TEMPS ARE IN THE MID
60S TO MID 70S.

WILL KEEP CHANCES FOR SHOWERS AND A FEW STORMS ACROSS THE AREA
THROUGH THE AFTERNOON. THE QUICKER MOVEMENT OF THE SYSTEM WILL
LIKELY PUSH MOST...IF NOT ALL...PCPN OUT OF THE AREA BY THE
EVENING. HAVE MADE A MINOR UPDATE TO RAISE WINDS ACROSS THE PLAINS
FOR LATE THIS MORNING. ALSO TWEAKED CLOUDS AND POPS CHANCES FOR
THE REST OF THE DAY.

&&

.SHORT TERM...TODAY THROUGH SATURDAY NIGHT
ISSUED AT 251 AM MDT FRI AUG 29 2014

STRONG SHORTWAVE TROUGH IS CROSSING THE CENTRAL PLAINS INTO THE ERN
DAKOTAS TO UPPER MIDWEST. ZONAL FLOW SITS ACROSS THE WRN CONUS WITH
A MUCH WEAK SHORTWAVE CROSS CNTRL/ERN MT. SURROUNDING RADAR SITES
SHOWING -SHRA/TSRA CROSSING ERN MT TO NRN WY. A SURFACE COLD FRONT
ALSO ASSOCIATED WITH THE WAVE/PRECIP IS SLIDING SE AND IS VISIBLE ON
THE BIS/BYZ RADARS.

COLD FRONT/UPPER WAVE WILL QUICKLY PUSH THROUGH THE CWA TODAY
BRINGING CHANCES FOR -SHRA/TSRA. LATEST TIMING APPEARS TO HAVE THE
AREA OF PRECIP OVER THE BLKHLS AREA BY LATE MORNING...THE CONTINUING
EWD INTO THE WRN SD PLAINS THROUGH THE AFTERNOON. STRONG INSTABILITY
DEVELOPING AHEAD OF THE FRONT OVER WRN/CNTRL SD PLAINS COULD RESULT
IN SOME STRONG STORMS THIS AFTERNOON...BUT SHEAR WILL BE QUITE WEAK
SO STORM BEHAVIOR IS EXPECTED TO BE MORE PULSE LIKE. TEMPS WILL
RANGE FROM THE MID 70S TO MID 80S...WITH COOLER TEMPS OVER NW SD/NE
WY WHERE THE FROPA OCCURS EARLIER THIS MORNING. WINDS IMMEDIATELY
BEHIND THE FRONTAL BOUNDARY WILL BECOME BREEZY...WITH GUSTS TO
AROUND 30KT...BUT WILL BE LIMITED TO AN HOUR OR TWO AFTER THE FRONT
PASSES.

WEAK RIDGING BUILDS BEHIND THE DEPARTING WAVE TONIGHT CLEARING OUT
PRECIP LATE TNGT TO SATURDAY MRNG. THE NEXT LONGWAVE TROUGH WILL
CROSS THE PACIFIC NW TO NRN ROCKIES SATURDAY...WITH ACTIVE SW FLOW
DEVELOPING. CHANCES FOR SHRA/TSRA WILL AGAIN RETURN SAT AFTN/EVNG.
GOOD INSTABILITY AND STRONG LL SHEAR OVER NW SD WILL RESULT IN
STRONG TO SEVERE TSRA SAT AFTN/EVNG. LARGE HAIL AND DAMAGING WINDS
ARE THE MAIN THREATS.

&&

.LONG TERM...SUNDAY THROUGH THURSDAY
ISSUED AT 251 AM MDT FRI AUG 29 2014

ACTIVE/PROGRESSIVE NORTHERN STREAM FLOW WILL CONTINUE THROUGH THE
PERIOD WITH A STRONG UPPER LEVEL TROUGH ON TRACK TO ADVECT THROUGH
THE REGION SUN...WITH A WEAKER SHORTWAVE IMPULSE LIKELY MONDAY.
TROUGH RELOADING OVER THE NE PAC TUE-WED FAVORED IN ECMWF/GFS/GEM
SOLUTIONS TUE...WHICH WILL SUPPORT SHORTWAVE RIDGING OVER THE
NORTHERN PLAINS WITH DRY AND WARMER CONDITIONS TUE-WED. NO SIG
CHANGES FROM THE PREVIOUS FORECAST GIVEN VERY GOOD DETERMINISTIC
MODEL CONSISTENCY AND CONTINUITY THROUGH THE PERIOD...WHICH IS IN
LINE WITH GEFS/NAEFS MEANS.

UPPER LEVEL TROUGH WILL BE IN THE PROCESS OF SHIFTING EAST ACROSS
THE NORTHERN PLAINS SUNDAY. ASSOCIATED MID LEVEL COLD POOL WILL
SUPPORT STEEP LL LAPSE RATES OVER THE FA WITH RESIDUAL LL MOISTURE
IN PLACE. DIURNAL HEATING COUPLED WITH BH/NE WY TERRAIN INFLUENCES
SHOULD SUPPORT SCT TO ISOLD SHRA/TS ESP SOUTH HALF OF THE FA.
REMAINED CLOSE TO PREVIOUS POP NUMBERS WITH MID RANGE CHANCE
COVERING PRECIP CONCERNS. OTHERWISE...A WEAKER WESTERLY FLOW IMPULSE
STILL INDICATED IN FORECAST MODELS MONDAY...POSSIBLY SUPPORTING A
FEW SHRA/TS...ALTHOUGH DRY PROFILES WILL LIMIT QPF AND
COVERAGE...ESP AWAY FROM THE BH. DRY CONDS EXPECTED TUE-WED WITH
MEAN DEEP LAYER RIDGING. THE NEXT NE PAC UPPER LEVEL TROUGH WILL
EJECT EAST INTO THE NORTHERN PLAINS WED NIGHT INTO
THUR...INTERACTING WITH A LEE SIDE TROUGH. INCREASING LSA WED NIGHT
THROUGH THUR WILL SUPPORT INCREASING CHANCES FOR SHRA/TS...FAR NW
SAT NIGHT WITH POPS TRENDING SOUTH THROUGH THUR AS THE UPPER TROUGH
SHIFTS EAST WITH THE REFLECTED SFC WAVE. DID BUMP POPS UP TO LOW
CHANCE NW 2/3 THUR NIGHT.

COOL/BELOW NORMAL TEMPS /5-10 DEGREES/ EXPECTED SUNDAY THROUGH
MONDAY...ESP NW AREAS. WARMING CONDITIONS CAN BE EXPECTED TUE-THUR
MOST AREAS. HOWEVER...NW AREAS MAY SEE THE START OF A COOLING TREND
THUR AS THE NEXT COLD FRONT SHIFTS SE INTO THE REGION.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 506 AM MDT FRI AUG 29 2014

MVFR CONDITIONS IN PATCHY FOG AND STRATUS WILL WANE OVER WESTERN
SOUTH DAKOTA THIS MORNING. A BAND OF ISOLATED TO SCATTERED SHOWERS
WILL MOVE EAST ACROSS NORTHEASTERN WYOMING AND INTO WESTERN SD
THIS MORNING AS AN UPPER LEVEL IMPULSE PUSHES EAST INTO THE
REGION. AN ISOLD MORNING TS IS ALSO POSSIBLE IN NE WY. THIS SAME
IMPULSE WILL SUPPORT ADDITIONAL CHANCES FOR SHRA/TS THIS AFTERNOON
WITH DIURNAL HEATING...MAINLY WESTERN AND CENTRAL SD. LOCAL MVFR
CONDS WILL BE POSSIBLE WITH ANY SHRA/TS THIS AFTERNOON.
OTHERWISE...VFR CONDITIONS WILL PREVAIL.

&&

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

$$

UPDATE...26
SHORT TERM...13
LONG TERM...JC
AVIATION...JC






000
FXUS63 KUNR 291553
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
953 AM MDT FRI AUG 29 2014

.UPDATE...
ISSUED AT 952 AM MDT FRI AUG 29 2014

CURRENT SURFACE ANALYSIS SHOWS LOW PRESSURE OVER NORTHEAST
SD...WITH COOL FRONT STRETCHING SOUTHWESTWARD ACROSS SD INTO
CENTRAL WY. UPPER LEVEL ANALYSIS SHOWS SLOW MOVING LOW OVER
SOUTHEAST NEB...WITH SHORTWAVE ENERGY BEHIND IT MOVING ACROSS THE
NORTHERN HIGH PLAINS. KUDX RADAR SHOWS ISOLATED TO SCATTERED
SHOWERS FROM FAR NORTHWEST SD THROUGH THE BLACK HILLS AND ACROSS
FAR EASTERN WY. A COUPLE OF LIGHTNING STRIKES HAVE BEEN NOTED WITH
THE ACTIVITY SO FAR. WINDS HAVE BEEN GUSTY ACROSS PARTS OF THE SD
PLAINS BEHIND THE FRONT...ESPECIALLY IN THE RAPID CITY AREA. WINDS
WILL GRADUALLY DIMINISH INTO THE AFTERNOON. TEMPS ARE IN THE MID
60S TO MID 70S.

WILL KEEP CHANCES FOR SHOWERS AND A FEW STORMS ACROSS THE AREA
THROUGH THE AFTERNOON. THE QUICKER MOVEMENT OF THE SYSTEM WILL
LIKELY PUSH MOST...IF NOT ALL...PCPN OUT OF THE AREA BY THE
EVENING. HAVE MADE A MINOR UPDATE TO RAISE WINDS ACROSS THE PLAINS
FOR LATE THIS MORNING. ALSO TWEAKED CLOUDS AND POPS CHANCES FOR
THE REST OF THE DAY.

&&

.SHORT TERM...TODAY THROUGH SATURDAY NIGHT
ISSUED AT 251 AM MDT FRI AUG 29 2014

STRONG SHORTWAVE TROUGH IS CROSSING THE CENTRAL PLAINS INTO THE ERN
DAKOTAS TO UPPER MIDWEST. ZONAL FLOW SITS ACROSS THE WRN CONUS WITH
A MUCH WEAK SHORTWAVE CROSS CNTRL/ERN MT. SURROUNDING RADAR SITES
SHOWING -SHRA/TSRA CROSSING ERN MT TO NRN WY. A SURFACE COLD FRONT
ALSO ASSOCIATED WITH THE WAVE/PRECIP IS SLIDING SE AND IS VISIBLE ON
THE BIS/BYZ RADARS.

COLD FRONT/UPPER WAVE WILL QUICKLY PUSH THROUGH THE CWA TODAY
BRINGING CHANCES FOR -SHRA/TSRA. LATEST TIMING APPEARS TO HAVE THE
AREA OF PRECIP OVER THE BLKHLS AREA BY LATE MORNING...THE CONTINUING
EWD INTO THE WRN SD PLAINS THROUGH THE AFTERNOON. STRONG INSTABILITY
DEVELOPING AHEAD OF THE FRONT OVER WRN/CNTRL SD PLAINS COULD RESULT
IN SOME STRONG STORMS THIS AFTERNOON...BUT SHEAR WILL BE QUITE WEAK
SO STORM BEHAVIOR IS EXPECTED TO BE MORE PULSE LIKE. TEMPS WILL
RANGE FROM THE MID 70S TO MID 80S...WITH COOLER TEMPS OVER NW SD/NE
WY WHERE THE FROPA OCCURS EARLIER THIS MORNING. WINDS IMMEDIATELY
BEHIND THE FRONTAL BOUNDARY WILL BECOME BREEZY...WITH GUSTS TO
AROUND 30KT...BUT WILL BE LIMITED TO AN HOUR OR TWO AFTER THE FRONT
PASSES.

WEAK RIDGING BUILDS BEHIND THE DEPARTING WAVE TONIGHT CLEARING OUT
PRECIP LATE TNGT TO SATURDAY MRNG. THE NEXT LONGWAVE TROUGH WILL
CROSS THE PACIFIC NW TO NRN ROCKIES SATURDAY...WITH ACTIVE SW FLOW
DEVELOPING. CHANCES FOR SHRA/TSRA WILL AGAIN RETURN SAT AFTN/EVNG.
GOOD INSTABILITY AND STRONG LL SHEAR OVER NW SD WILL RESULT IN
STRONG TO SEVERE TSRA SAT AFTN/EVNG. LARGE HAIL AND DAMAGING WINDS
ARE THE MAIN THREATS.

&&

.LONG TERM...SUNDAY THROUGH THURSDAY
ISSUED AT 251 AM MDT FRI AUG 29 2014

ACTIVE/PROGRESSIVE NORTHERN STREAM FLOW WILL CONTINUE THROUGH THE
PERIOD WITH A STRONG UPPER LEVEL TROUGH ON TRACK TO ADVECT THROUGH
THE REGION SUN...WITH A WEAKER SHORTWAVE IMPULSE LIKELY MONDAY.
TROUGH RELOADING OVER THE NE PAC TUE-WED FAVORED IN ECMWF/GFS/GEM
SOLUTIONS TUE...WHICH WILL SUPPORT SHORTWAVE RIDGING OVER THE
NORTHERN PLAINS WITH DRY AND WARMER CONDITIONS TUE-WED. NO SIG
CHANGES FROM THE PREVIOUS FORECAST GIVEN VERY GOOD DETERMINISTIC
MODEL CONSISTENCY AND CONTINUITY THROUGH THE PERIOD...WHICH IS IN
LINE WITH GEFS/NAEFS MEANS.

UPPER LEVEL TROUGH WILL BE IN THE PROCESS OF SHIFTING EAST ACROSS
THE NORTHERN PLAINS SUNDAY. ASSOCIATED MID LEVEL COLD POOL WILL
SUPPORT STEEP LL LAPSE RATES OVER THE FA WITH RESIDUAL LL MOISTURE
IN PLACE. DIURNAL HEATING COUPLED WITH BH/NE WY TERRAIN INFLUENCES
SHOULD SUPPORT SCT TO ISOLD SHRA/TS ESP SOUTH HALF OF THE FA.
REMAINED CLOSE TO PREVIOUS POP NUMBERS WITH MID RANGE CHANCE
COVERING PRECIP CONCERNS. OTHERWISE...A WEAKER WESTERLY FLOW IMPULSE
STILL INDICATED IN FORECAST MODELS MONDAY...POSSIBLY SUPPORTING A
FEW SHRA/TS...ALTHOUGH DRY PROFILES WILL LIMIT QPF AND
COVERAGE...ESP AWAY FROM THE BH. DRY CONDS EXPECTED TUE-WED WITH
MEAN DEEP LAYER RIDGING. THE NEXT NE PAC UPPER LEVEL TROUGH WILL
EJECT EAST INTO THE NORTHERN PLAINS WED NIGHT INTO
THUR...INTERACTING WITH A LEE SIDE TROUGH. INCREASING LSA WED NIGHT
THROUGH THUR WILL SUPPORT INCREASING CHANCES FOR SHRA/TS...FAR NW
SAT NIGHT WITH POPS TRENDING SOUTH THROUGH THUR AS THE UPPER TROUGH
SHIFTS EAST WITH THE REFLECTED SFC WAVE. DID BUMP POPS UP TO LOW
CHANCE NW 2/3 THUR NIGHT.

COOL/BELOW NORMAL TEMPS /5-10 DEGREES/ EXPECTED SUNDAY THROUGH
MONDAY...ESP NW AREAS. WARMING CONDITIONS CAN BE EXPECTED TUE-THUR
MOST AREAS. HOWEVER...NW AREAS MAY SEE THE START OF A COOLING TREND
THUR AS THE NEXT COLD FRONT SHIFTS SE INTO THE REGION.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 506 AM MDT FRI AUG 29 2014

MVFR CONDITIONS IN PATCHY FOG AND STRATUS WILL WANE OVER WESTERN
SOUTH DAKOTA THIS MORNING. A BAND OF ISOLATED TO SCATTERED SHOWERS
WILL MOVE EAST ACROSS NORTHEASTERN WYOMING AND INTO WESTERN SD
THIS MORNING AS AN UPPER LEVEL IMPULSE PUSHES EAST INTO THE
REGION. AN ISOLD MORNING TS IS ALSO POSSIBLE IN NE WY. THIS SAME
IMPULSE WILL SUPPORT ADDITIONAL CHANCES FOR SHRA/TS THIS AFTERNOON
WITH DIURNAL HEATING...MAINLY WESTERN AND CENTRAL SD. LOCAL MVFR
CONDS WILL BE POSSIBLE WITH ANY SHRA/TS THIS AFTERNOON.
OTHERWISE...VFR CONDITIONS WILL PREVAIL.

&&

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

$$

UPDATE...26
SHORT TERM...13
LONG TERM...JC
AVIATION...JC






  [top]

000
FXUS65 KCYS 291539
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
939 AM MDT FRI AUG 29 2014

.UPDATE...
ISSUED AT 922 AM MDT FRI AUG 29 2014

OVERALL FCST IS IN GOOD SHAPE TODAY. BROAD UPPER-LEVEL RIDGING
WILL DOMINATE THE FLOW PATTERN THROUGH THE AFTN WITH ISOLATED TO
WIDELY SCATTERED SHOWERS AND TSTMS EXPECTED WITH A WEAK MIDLVL
SHORTWAVE MOVING ACROSS NORTH CENTRAL WY ATTM. ADDED SOME LOW END
POPS TO OUR EAST CENTRAL WY AND NORTHERN PANHANDLE ZONES THROUGH
18Z AS SOME WEAK ECHOS HAVE ALREADY SHOWN UP ON RADAR BETWEEN LUSK
AND GLENDO. LATEST VISIBLE SATELLITE SHOWS A CONSIDERABLE AMOUNT
OF SMOKE HEADING IN OUR DIRECTION FROM WILDFIRES NEAR THE OREGON
AND CALIFORNIA BORDER. MAIN QUESTION IS WHETHER THIS WILL BE DENSE
ENOUGH TO HAVE A SIGNIFICANT IMPACT ON TEMPS TODAY...SO WILL NEED
TO WATCH AS THE SMOKE SPREADS FROM WEST TO EAST ACROSS THE CWA.
DID NOT MAKE ANY CHANGES FOR THE TIME BEING ...THINKING IT WOULD
ONLY BE A COUPLE OF DEGREES IF SO.

&&

.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 430 AM MDT FRI AUG 29 2014

UPPER TROUGH RESPONSIBLE FOR THE COOL AND UNSETTLED WEATHER THE PAST
FEW DAYS WAS LOCATED OVER THE GREAT PLAINS SLOWLY PROGRESSING EAST.
A TRANSITORY SHORTWAVE RIDGE ON ITS HEELS WAS PROVIDING A DRIER
NORTHWEST FLOW ALOFT ACROSS THE CWA. THE NEXT WEATHER MAKER WAS A
SHORTWAVE TROUGH MOVING THROUGH CENTRAL MT AND NORTHWEST WY ACCOMPANIED
BY SCATTERED SHOWERS AND ISOLATED TSTORMS. A WEAK SURFACE RIDGE DOMINATED
THE CWA... WITH A COLD FRONT LOCATED FROM NORTHWEST ND TO WEST CENTRAL
MT. WINDS WERE LIGHT WITH TEMP/DEW POINT SPREADS OF A FEW DEGREES OVER
WESTERN NE. COULD SEE SOME PATCHY FOG DEVELOP BY SUNRISE IN THESE AREAS.

GREAT PLAINS TROUGH CONTINUES ITS EASTWARD TREK TOWARD THE MS VALLEY
THROUGH SATURDAY. MEANWHILE...THE SHORTWAVE TO THE NORTH MAKES A
BEELINE FOR THE NORTHERN GREAT PLAINS AND UPPER MIDWEST. A UPPER RIDGE
WEST OF THE CONTINENTAL DIVIDE SLIDES QUICKLY EAST INTO THE NORTHERN
AND CENTRAL GREAT PLAINS SATURDAY AS THE NEXT PACIFIC TROUGH BROADENS
WITH ITS AXIS OVER THE FRONT RANGE BY MIDDAY SUNDAY.

TODAY WILL BE DRIER AND WARMER. ISOLATED AFTERNOON CONVECTION WILL DEVELOP
OVER AND EAST OF THE MOUNTAINS WHERE SBCAPES RANGE FROM 400-800 J/KG.
MAIN THREATS WITH THE TSTORMS WILL BE LIGHTNING AND GUSTY WINDS. MODEL
QPFS GENERALLY AVERAGE FROM 0.10-0.25 INCH. 700MB TEMPERATURES WILL
BE ABOUT 5 DEGREES WARMER THIS AFTERNOON WITH HIGHS IN THE UPPER 70S
TO MIDDLE 80S FOR THE PLAINS. CONVECTION MAY LINGER THROUGH THE EARLY
EVENING FOR THE SOUTHEAST WY MOUNTAINS.

SATURDAY MORNING WILL BE DRY TO START WITH WARMER AND BREEZY CONDITIONS
THROUGHOUT THE DAY IN ADVANCE OF THE PACIFIC COLD FRONT AND TROUGH.
HIGH TEMPERATURES WILL RISE INTO THE 80S TO LOWER 90S FOR THE PLAINS.
PACIFIC MOISTURE WILL SPREAD EAST ACROSS WY SATURDAY AFTERNOON AND
WESTERN NE SATURDAY EVENING. INSTABILITY INCREASES EAST OF THE LARAMIE
RANGE WITH SBCAPES OF 800-1200 J/KG. EXPECT ISOLATED TO SCATTERED
TSTORM COVERAGE. BESIDE THE WIND AND LIGHTNING THREATS...LOCALLY HEAVY
RAINFALL WILL BE A POSSIBILITY. CONVECTION WILL LIKELY CONTINUE INTO
THE LATE NIGHT HOURS AS SHORTWAVE ENERGY PRECEDING THE TROUGH PASSES
THROUGH.

SUNDAY WILL BEGIN UNSETTLED WITH SCATTERED SHOWERS/TSTORMS ACCOMPANYING
THE TROUGH...AND TAPERING OFF FROM WEST TO EAST DURING THE AFTERNOON
WITH PASSAGE OF THE COLD FRONT. IT WILL TURN BREEZY AND MUCH COOLER
/10-15 DEGREES/ IN THE AFTERNOON WITH HIGHS IN THE 50S AND 60S WEST...
70S EAST.

.LONG TERM...(SUNDAY NIGHT THROUGH THURSDAY)
ISSUED AT 325 AM MDT FRI AUG 29 2014

MEDIUM AND LONG RANGE MODELS ARE IN FAIR AGREEMENT THROUGH NEXT WEEK.
EXPECT A DRIER AND WARMER PATTERN COMPARED TO THE LAST FEW WEEKS AS
THE SOUTHWEST MONSOON IS SHOWING SIGNS OF COMING TO AN END. OUTSIDE
OF A FEW SHOWERS AND TSTORMS ON MONDAY AS A WEAK DISTURBANCE QUICKLY
MOVES EASTWARD OVER THE AREA...TUESDAY THROUGH THURSDAY WILL LIKELY
BE DRY WITH TEMPERATURES ABOVE NORMAL. HIGHS IN THE 80S TO AROUND
90 WILL BE COMMON ACROSS THE HIGH PLAINS...WITH THE HIGHER VALLEYS
REMAINING IN THE UPPER 70S TO AROUND 80. MODELS INDICATE A PERIOD
OF TRANSITION IN THE OVERALL LONG WAVE PATTERN AS THE POLAR JET
STREAM BECOMES MORE DEFINED AND MORE ACTIVE BY THE MIDDLE OF THE
WEEK NEAR THE CANADIAN BORDER.

BY LATE NEXT WEEK...MODELS SHOW AN UPPER LEVEL TROUGH STALLING OVER
THE PACIFIC NORTHWEST. HIGH PRESSURE ALOFT WILL BUILD OVER THE SOUTH
CENTRAL UNITED STATES AS SOME SUBTROPICAL MOISTURE BEGINS TO ADVECT
NORTHWARD OVER THE CENTRAL ROCKY MOUNTAINS. ADDED A SLIGHT CHANCE OF
SHOWERS AND TSTORMS TO THE FORECAST BY LATE THURSDAY NIGHT AND INTO
FRIDAY WITH THE GFS AND ECMWF SHOWING SOME ORGANIZED CONVECTION OVER
THE FORECAST AREA.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY NIGHT)
ISSUED AT 207 AM MDT FRI AUG 29 2014

VFR CONDITIONS WILL PREVAIL TODAY AS SURFACE WINDS WILL SHIFT INTO THE
NORTH...BUT WILL BE RATHER LIGHT THROUGH THE DAY. ISOLATED SHOWERS AND
TSTORMS ARE EXPECTED BY THIS AFTERNOON...MAINLY EAST OF THE LARAMIE
RANGE.


&&

.FIRE WEATHER...
ISSUED AT 317 AM MDT FRI AUG 29 2014

TODAY WILL BE DRIER AND WARMER THAN THE PAST FEW DAYS. A UPPER LEVEL
DISTURBANCE WILL ADVANCE EAST FROM MONTANA AND NORTHERN WYOMING TO THE
DAKOTAS BY THIS EVENING. A COLD FRONT WILL MOVE SOUTH THROUGH EAST
CENTRAL WYOMING THIS EVENING THEN EAST AS A WARM FRONT SATURDAY. THERE
WILL BE A SLIGHT CHANCE OF AFTERNOON THUNDERSTORMS TODAY...MAINLY ALONG
AND EAST OF THE LARAMIE RANGE. GUSTY WEST TO SOUTHWEST WINDS WILL DEVELOP
SATURDAY IN ADVANCE OF A PACIFIC FRONT AND TROUGH. CHANCES FOR THUNDERSTORMS
WILL INCREASE SATURDAY AFTERNOON AND CONTINUE SUNDAY FOLLOWING THE PASSAGE
OF THE FRONT. AFTER A WARM SATURDAY...SUNDAY WILL BE MUCH COOLER. ANOTHER
DISTURBANCE WILL MOVE THROUGH THE DISTRICTS LABOR DAY BRINGING A SLIGHT
CHANCE OF AFTERNOON THUNDERSTORMS ALONG AND EAST OF THE MOUNTAINS. IT
WILL TREND DRIER AND WARMER FOR THE MIDDLE OF NEXT WEEK.

&&

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

$$

UPDATE...HAMMER
SHORT TERM...JAMSKI
LONG TERM...TJT
AVIATION...TJT
FIRE WEATHER...JAMSKI






000
FXUS65 KCYS 291539
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
939 AM MDT FRI AUG 29 2014

.UPDATE...
ISSUED AT 922 AM MDT FRI AUG 29 2014

OVERALL FCST IS IN GOOD SHAPE TODAY. BROAD UPPER-LEVEL RIDGING
WILL DOMINATE THE FLOW PATTERN THROUGH THE AFTN WITH ISOLATED TO
WIDELY SCATTERED SHOWERS AND TSTMS EXPECTED WITH A WEAK MIDLVL
SHORTWAVE MOVING ACROSS NORTH CENTRAL WY ATTM. ADDED SOME LOW END
POPS TO OUR EAST CENTRAL WY AND NORTHERN PANHANDLE ZONES THROUGH
18Z AS SOME WEAK ECHOS HAVE ALREADY SHOWN UP ON RADAR BETWEEN LUSK
AND GLENDO. LATEST VISIBLE SATELLITE SHOWS A CONSIDERABLE AMOUNT
OF SMOKE HEADING IN OUR DIRECTION FROM WILDFIRES NEAR THE OREGON
AND CALIFORNIA BORDER. MAIN QUESTION IS WHETHER THIS WILL BE DENSE
ENOUGH TO HAVE A SIGNIFICANT IMPACT ON TEMPS TODAY...SO WILL NEED
TO WATCH AS THE SMOKE SPREADS FROM WEST TO EAST ACROSS THE CWA.
DID NOT MAKE ANY CHANGES FOR THE TIME BEING ...THINKING IT WOULD
ONLY BE A COUPLE OF DEGREES IF SO.

&&

.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 430 AM MDT FRI AUG 29 2014

UPPER TROUGH RESPONSIBLE FOR THE COOL AND UNSETTLED WEATHER THE PAST
FEW DAYS WAS LOCATED OVER THE GREAT PLAINS SLOWLY PROGRESSING EAST.
A TRANSITORY SHORTWAVE RIDGE ON ITS HEELS WAS PROVIDING A DRIER
NORTHWEST FLOW ALOFT ACROSS THE CWA. THE NEXT WEATHER MAKER WAS A
SHORTWAVE TROUGH MOVING THROUGH CENTRAL MT AND NORTHWEST WY ACCOMPANIED
BY SCATTERED SHOWERS AND ISOLATED TSTORMS. A WEAK SURFACE RIDGE DOMINATED
THE CWA... WITH A COLD FRONT LOCATED FROM NORTHWEST ND TO WEST CENTRAL
MT. WINDS WERE LIGHT WITH TEMP/DEW POINT SPREADS OF A FEW DEGREES OVER
WESTERN NE. COULD SEE SOME PATCHY FOG DEVELOP BY SUNRISE IN THESE AREAS.

GREAT PLAINS TROUGH CONTINUES ITS EASTWARD TREK TOWARD THE MS VALLEY
THROUGH SATURDAY. MEANWHILE...THE SHORTWAVE TO THE NORTH MAKES A
BEELINE FOR THE NORTHERN GREAT PLAINS AND UPPER MIDWEST. A UPPER RIDGE
WEST OF THE CONTINENTAL DIVIDE SLIDES QUICKLY EAST INTO THE NORTHERN
AND CENTRAL GREAT PLAINS SATURDAY AS THE NEXT PACIFIC TROUGH BROADENS
WITH ITS AXIS OVER THE FRONT RANGE BY MIDDAY SUNDAY.

TODAY WILL BE DRIER AND WARMER. ISOLATED AFTERNOON CONVECTION WILL DEVELOP
OVER AND EAST OF THE MOUNTAINS WHERE SBCAPES RANGE FROM 400-800 J/KG.
MAIN THREATS WITH THE TSTORMS WILL BE LIGHTNING AND GUSTY WINDS. MODEL
QPFS GENERALLY AVERAGE FROM 0.10-0.25 INCH. 700MB TEMPERATURES WILL
BE ABOUT 5 DEGREES WARMER THIS AFTERNOON WITH HIGHS IN THE UPPER 70S
TO MIDDLE 80S FOR THE PLAINS. CONVECTION MAY LINGER THROUGH THE EARLY
EVENING FOR THE SOUTHEAST WY MOUNTAINS.

SATURDAY MORNING WILL BE DRY TO START WITH WARMER AND BREEZY CONDITIONS
THROUGHOUT THE DAY IN ADVANCE OF THE PACIFIC COLD FRONT AND TROUGH.
HIGH TEMPERATURES WILL RISE INTO THE 80S TO LOWER 90S FOR THE PLAINS.
PACIFIC MOISTURE WILL SPREAD EAST ACROSS WY SATURDAY AFTERNOON AND
WESTERN NE SATURDAY EVENING. INSTABILITY INCREASES EAST OF THE LARAMIE
RANGE WITH SBCAPES OF 800-1200 J/KG. EXPECT ISOLATED TO SCATTERED
TSTORM COVERAGE. BESIDE THE WIND AND LIGHTNING THREATS...LOCALLY HEAVY
RAINFALL WILL BE A POSSIBILITY. CONVECTION WILL LIKELY CONTINUE INTO
THE LATE NIGHT HOURS AS SHORTWAVE ENERGY PRECEDING THE TROUGH PASSES
THROUGH.

SUNDAY WILL BEGIN UNSETTLED WITH SCATTERED SHOWERS/TSTORMS ACCOMPANYING
THE TROUGH...AND TAPERING OFF FROM WEST TO EAST DURING THE AFTERNOON
WITH PASSAGE OF THE COLD FRONT. IT WILL TURN BREEZY AND MUCH COOLER
/10-15 DEGREES/ IN THE AFTERNOON WITH HIGHS IN THE 50S AND 60S WEST...
70S EAST.

.LONG TERM...(SUNDAY NIGHT THROUGH THURSDAY)
ISSUED AT 325 AM MDT FRI AUG 29 2014

MEDIUM AND LONG RANGE MODELS ARE IN FAIR AGREEMENT THROUGH NEXT WEEK.
EXPECT A DRIER AND WARMER PATTERN COMPARED TO THE LAST FEW WEEKS AS
THE SOUTHWEST MONSOON IS SHOWING SIGNS OF COMING TO AN END. OUTSIDE
OF A FEW SHOWERS AND TSTORMS ON MONDAY AS A WEAK DISTURBANCE QUICKLY
MOVES EASTWARD OVER THE AREA...TUESDAY THROUGH THURSDAY WILL LIKELY
BE DRY WITH TEMPERATURES ABOVE NORMAL. HIGHS IN THE 80S TO AROUND
90 WILL BE COMMON ACROSS THE HIGH PLAINS...WITH THE HIGHER VALLEYS
REMAINING IN THE UPPER 70S TO AROUND 80. MODELS INDICATE A PERIOD
OF TRANSITION IN THE OVERALL LONG WAVE PATTERN AS THE POLAR JET
STREAM BECOMES MORE DEFINED AND MORE ACTIVE BY THE MIDDLE OF THE
WEEK NEAR THE CANADIAN BORDER.

BY LATE NEXT WEEK...MODELS SHOW AN UPPER LEVEL TROUGH STALLING OVER
THE PACIFIC NORTHWEST. HIGH PRESSURE ALOFT WILL BUILD OVER THE SOUTH
CENTRAL UNITED STATES AS SOME SUBTROPICAL MOISTURE BEGINS TO ADVECT
NORTHWARD OVER THE CENTRAL ROCKY MOUNTAINS. ADDED A SLIGHT CHANCE OF
SHOWERS AND TSTORMS TO THE FORECAST BY LATE THURSDAY NIGHT AND INTO
FRIDAY WITH THE GFS AND ECMWF SHOWING SOME ORGANIZED CONVECTION OVER
THE FORECAST AREA.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY NIGHT)
ISSUED AT 207 AM MDT FRI AUG 29 2014

VFR CONDITIONS WILL PREVAIL TODAY AS SURFACE WINDS WILL SHIFT INTO THE
NORTH...BUT WILL BE RATHER LIGHT THROUGH THE DAY. ISOLATED SHOWERS AND
TSTORMS ARE EXPECTED BY THIS AFTERNOON...MAINLY EAST OF THE LARAMIE
RANGE.


&&

.FIRE WEATHER...
ISSUED AT 317 AM MDT FRI AUG 29 2014

TODAY WILL BE DRIER AND WARMER THAN THE PAST FEW DAYS. A UPPER LEVEL
DISTURBANCE WILL ADVANCE EAST FROM MONTANA AND NORTHERN WYOMING TO THE
DAKOTAS BY THIS EVENING. A COLD FRONT WILL MOVE SOUTH THROUGH EAST
CENTRAL WYOMING THIS EVENING THEN EAST AS A WARM FRONT SATURDAY. THERE
WILL BE A SLIGHT CHANCE OF AFTERNOON THUNDERSTORMS TODAY...MAINLY ALONG
AND EAST OF THE LARAMIE RANGE. GUSTY WEST TO SOUTHWEST WINDS WILL DEVELOP
SATURDAY IN ADVANCE OF A PACIFIC FRONT AND TROUGH. CHANCES FOR THUNDERSTORMS
WILL INCREASE SATURDAY AFTERNOON AND CONTINUE SUNDAY FOLLOWING THE PASSAGE
OF THE FRONT. AFTER A WARM SATURDAY...SUNDAY WILL BE MUCH COOLER. ANOTHER
DISTURBANCE WILL MOVE THROUGH THE DISTRICTS LABOR DAY BRINGING A SLIGHT
CHANCE OF AFTERNOON THUNDERSTORMS ALONG AND EAST OF THE MOUNTAINS. IT
WILL TREND DRIER AND WARMER FOR THE MIDDLE OF NEXT WEEK.

&&

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

$$

UPDATE...HAMMER
SHORT TERM...JAMSKI
LONG TERM...TJT
AVIATION...TJT
FIRE WEATHER...JAMSKI







000
FXUS63 KUNR 291123
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
523 AM MDT FRI AUG 29 2014

.SHORT TERM...TODAY THROUGH SATURDAY NIGHT
ISSUED AT 251 AM MDT FRI AUG 29 2014

STRONG SHORTWAVE TROUGH IS CROSSING THE CENTRAL PLAINS INTO THE ERN
DAKOTAS TO UPPER MIDWEST. ZONAL FLOW SITS ACROSS THE WRN CONUS WITH
A MUCH WEAK SHORTWAVE CROSS CNTRL/ERN MT. SURROUNDING RADAR SITES
SHOWING -SHRA/TSRA CROSSING ERN MT TO NRN WY. A SURFACE COLD FRONT
ALSO ASSOCIATED WITH THE WAVE/PRECIP IS SLIDING SE AND IS VISIBLE ON
THE BIS/BYZ RADARS.

COLD FRONT/UPPER WAVE WILL QUICKLY PUSH THROUGH THE CWA TODAY
BRINGING CHANCES FOR -SHRA/TSRA. LATEST TIMING APPEARS TO HAVE THE
AREA OF PRECIP OVER THE BLKHLS AREA BY LATE MORNING...THE CONTINUING
EWD INTO THE WRN SD PLAINS THROUGH THE AFTERNOON. STRONG INSTABILITY
DEVELOPING AHEAD OF THE FRONT OVER WRN/CNTRL SD PLAINS COULD RESULT
IN SOME STRONG STORMS THIS AFTERNOON...BUT SHEAR WILL BE QUITE WEAK
SO STORM BEHAVIOR IS EXPECTED TO BE MORE PULSE LIKE. TEMPS WILL
RANGE FROM THE MID 70S TO MID 80S...WITH COOLER TEMPS OVER NW SD/NE
WY WHERE THE FROPA OCCURS EARLIER THIS MORNING. WINDS IMMEDIATELY
BEHIND THE FRONTAL BOUNDARY WILL BECOME BREEZY...WITH GUSTS TO
AROUND 30KT...BUT WILL BE LIMITED TO AN HOUR OR TWO AFTER THE FRONT
PASSES.

WEAK RIDGING BUILDS BEHIND THE DEPARTING WAVE TONIGHT CLEARING OUT
PRECIP LATE TNGT TO SATURDAY MRNG. THE NEXT LONGWAVE TROUGH WILL
CROSS THE PACIFIC NW TO NRN ROCKIES SATURDAY...WITH ACTIVE SW FLOW
DEVELOPING. CHANCES FOR SHRA/TSRA WILL AGAIN RETURN SAT AFTN/EVNG.
GOOD INSTABILITY AND STRONG LL SHEAR OVER NW SD WILL RESULT IN
STRONG TO SEVERE TSRA SAT AFTN/EVNG. LARGE HAIL AND DAMAGING WINDS
ARE THE MAIN THREATS.

&&

.LONG TERM...SUNDAY THROUGH THURSDAY
ISSUED AT 251 AM MDT FRI AUG 29 2014

ACTIVE/PROGRESSIVE NORTHERN STREAM FLOW WILL CONTINUE THROUGH THE
PERIOD WITH A STRONG UPPER LEVEL TROUGH ON TRACK TO ADVECT THROUGH
THE REGION SUN...WITH A WEAKER SHORTWAVE IMPULSE LIKELY MONDAY.
TROUGH RELOADING OVER THE NE PAC TUE-WED FAVORED IN ECMWF/GFS/GEM
SOLUTIONS TUE...WHICH WILL SUPPORT SHORTWAVE RIDGING OVER THE
NORTHERN PLAINS WITH DRY AND WARMER CONDITIONS TUE-WED. NO SIG
CHANGES FROM THE PREVIOUS FORECAST GIVEN VERY GOOD DETERMINISTIC
MODEL CONSISTENCY AND CONTINUITY THROUGH THE PERIOD...WHICH IS IN
LINE WITH GEFS/NAEFS MEANS.

UPPER LEVEL TROUGH WILL BE IN THE PROCESS OF SHIFTING EAST ACROSS
THE NORTHERN PLAINS SUNDAY. ASSOCIATED MID LEVEL COLD POOL WILL
SUPPORT STEEP LL LAPSE RATES OVER THE FA WITH RESIDUAL LL MOISTURE
IN PLACE. DIURNAL HEATING COUPLED WITH BH/NE WY TERRAIN INFLUENCES
SHOULD SUPPORT SCT TO ISOLD SHRA/TS ESP SOUTH HALF OF THE FA.
REMAINED CLOSE TO PREVIOUS POP NUMBERS WITH MID RANGE CHANCE
COVERING PRECIP CONCERNS. OTHERWISE...A WEAKER WESTERLY FLOW IMPULSE
STILL INDICATED IN FORECAST MODELS MONDAY...POSSIBLY SUPPORTING A
FEW SHRA/TS...ALTHOUGH DRY PROFILES WILL LIMIT QPF AND
COVERAGE...ESP AWAY FROM THE BH. DRY CONDS EXPECTED TUE-WED WITH
MEAN DEEP LAYER RIDGING. THE NEXT NE PAC UPPER LEVEL TROUGH WILL
EJECT EAST INTO THE NORTHERN PLAINS WED NIGHT INTO
THUR...INTERACTING WITH A LEE SIDE TROUGH. INCREASING LSA WED NIGHT
THROUGH THUR WILL SUPPORT INCREASING CHANCES FOR SHRA/TS...FAR NW
SAT NIGHT WITH POPS TRENDING SOUTH THROUGH THUR AS THE UPPER TROUGH
SHIFTS EAST WITH THE REFLECTED SFC WAVE. DID BUMP POPS UP TO LOW
CHANCE NW 2/3 THUR NIGHT.

COOL/BELOW NORMAL TEMPS /5-10 DEGREES/ EXPECTED SUNDAY THROUGH
MONDAY...ESP NW AREAS. WARMING CONDITIONS CAN BE EXPECTED TUE-THUR
MOST AREAS. HOWEVER...NW AREAS MAY SEE THE START OF A COOLING TREND
THUR AS THE NEXT COLD FRONT SHIFTS SE INTO THE REGION.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 506 AM MDT FRI AUG 29 2014

MVFR CONDITIONS IN PATCHY FOG AND STRATUS WILL WANE OVER WESTERN
SOUTH DAKOTA THIS MORNING. A BAND OF ISOLATED TO SCATTERED SHOWERS
WILL MOVE EAST ACROSS NORTHEASTERN WYOMING AND INTO WESTERN SD
THIS MORNING AS AN UPPER LEVEL IMPULSE PUSHES EAST INTO THE
REGION. AN ISOLD MORNING TS IS ALSO POSSIBLE IN NE WY. THIS SAME
IMPULSE WILL SUPPORT ADDITIONAL CHANCES FOR SHRA/TS THIS AFTERNOON
WITH DIURNAL HEATING...MAINLY WESTERN AND CENTRAL SD. LOCAL MVFR
CONDS WILL BE POSSIBLE WITH ANY SHRA/TS THIS AFTERNOON.
OTHERWISE...VFR CONDITIONS WILL PREVAIL.

&&

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

$$

SHORT TERM...13
LONG TERM...JC
AVIATION...JC







000
FXUS63 KUNR 291123
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
523 AM MDT FRI AUG 29 2014

.SHORT TERM...TODAY THROUGH SATURDAY NIGHT
ISSUED AT 251 AM MDT FRI AUG 29 2014

STRONG SHORTWAVE TROUGH IS CROSSING THE CENTRAL PLAINS INTO THE ERN
DAKOTAS TO UPPER MIDWEST. ZONAL FLOW SITS ACROSS THE WRN CONUS WITH
A MUCH WEAK SHORTWAVE CROSS CNTRL/ERN MT. SURROUNDING RADAR SITES
SHOWING -SHRA/TSRA CROSSING ERN MT TO NRN WY. A SURFACE COLD FRONT
ALSO ASSOCIATED WITH THE WAVE/PRECIP IS SLIDING SE AND IS VISIBLE ON
THE BIS/BYZ RADARS.

COLD FRONT/UPPER WAVE WILL QUICKLY PUSH THROUGH THE CWA TODAY
BRINGING CHANCES FOR -SHRA/TSRA. LATEST TIMING APPEARS TO HAVE THE
AREA OF PRECIP OVER THE BLKHLS AREA BY LATE MORNING...THE CONTINUING
EWD INTO THE WRN SD PLAINS THROUGH THE AFTERNOON. STRONG INSTABILITY
DEVELOPING AHEAD OF THE FRONT OVER WRN/CNTRL SD PLAINS COULD RESULT
IN SOME STRONG STORMS THIS AFTERNOON...BUT SHEAR WILL BE QUITE WEAK
SO STORM BEHAVIOR IS EXPECTED TO BE MORE PULSE LIKE. TEMPS WILL
RANGE FROM THE MID 70S TO MID 80S...WITH COOLER TEMPS OVER NW SD/NE
WY WHERE THE FROPA OCCURS EARLIER THIS MORNING. WINDS IMMEDIATELY
BEHIND THE FRONTAL BOUNDARY WILL BECOME BREEZY...WITH GUSTS TO
AROUND 30KT...BUT WILL BE LIMITED TO AN HOUR OR TWO AFTER THE FRONT
PASSES.

WEAK RIDGING BUILDS BEHIND THE DEPARTING WAVE TONIGHT CLEARING OUT
PRECIP LATE TNGT TO SATURDAY MRNG. THE NEXT LONGWAVE TROUGH WILL
CROSS THE PACIFIC NW TO NRN ROCKIES SATURDAY...WITH ACTIVE SW FLOW
DEVELOPING. CHANCES FOR SHRA/TSRA WILL AGAIN RETURN SAT AFTN/EVNG.
GOOD INSTABILITY AND STRONG LL SHEAR OVER NW SD WILL RESULT IN
STRONG TO SEVERE TSRA SAT AFTN/EVNG. LARGE HAIL AND DAMAGING WINDS
ARE THE MAIN THREATS.

&&

.LONG TERM...SUNDAY THROUGH THURSDAY
ISSUED AT 251 AM MDT FRI AUG 29 2014

ACTIVE/PROGRESSIVE NORTHERN STREAM FLOW WILL CONTINUE THROUGH THE
PERIOD WITH A STRONG UPPER LEVEL TROUGH ON TRACK TO ADVECT THROUGH
THE REGION SUN...WITH A WEAKER SHORTWAVE IMPULSE LIKELY MONDAY.
TROUGH RELOADING OVER THE NE PAC TUE-WED FAVORED IN ECMWF/GFS/GEM
SOLUTIONS TUE...WHICH WILL SUPPORT SHORTWAVE RIDGING OVER THE
NORTHERN PLAINS WITH DRY AND WARMER CONDITIONS TUE-WED. NO SIG
CHANGES FROM THE PREVIOUS FORECAST GIVEN VERY GOOD DETERMINISTIC
MODEL CONSISTENCY AND CONTINUITY THROUGH THE PERIOD...WHICH IS IN
LINE WITH GEFS/NAEFS MEANS.

UPPER LEVEL TROUGH WILL BE IN THE PROCESS OF SHIFTING EAST ACROSS
THE NORTHERN PLAINS SUNDAY. ASSOCIATED MID LEVEL COLD POOL WILL
SUPPORT STEEP LL LAPSE RATES OVER THE FA WITH RESIDUAL LL MOISTURE
IN PLACE. DIURNAL HEATING COUPLED WITH BH/NE WY TERRAIN INFLUENCES
SHOULD SUPPORT SCT TO ISOLD SHRA/TS ESP SOUTH HALF OF THE FA.
REMAINED CLOSE TO PREVIOUS POP NUMBERS WITH MID RANGE CHANCE
COVERING PRECIP CONCERNS. OTHERWISE...A WEAKER WESTERLY FLOW IMPULSE
STILL INDICATED IN FORECAST MODELS MONDAY...POSSIBLY SUPPORTING A
FEW SHRA/TS...ALTHOUGH DRY PROFILES WILL LIMIT QPF AND
COVERAGE...ESP AWAY FROM THE BH. DRY CONDS EXPECTED TUE-WED WITH
MEAN DEEP LAYER RIDGING. THE NEXT NE PAC UPPER LEVEL TROUGH WILL
EJECT EAST INTO THE NORTHERN PLAINS WED NIGHT INTO
THUR...INTERACTING WITH A LEE SIDE TROUGH. INCREASING LSA WED NIGHT
THROUGH THUR WILL SUPPORT INCREASING CHANCES FOR SHRA/TS...FAR NW
SAT NIGHT WITH POPS TRENDING SOUTH THROUGH THUR AS THE UPPER TROUGH
SHIFTS EAST WITH THE REFLECTED SFC WAVE. DID BUMP POPS UP TO LOW
CHANCE NW 2/3 THUR NIGHT.

COOL/BELOW NORMAL TEMPS /5-10 DEGREES/ EXPECTED SUNDAY THROUGH
MONDAY...ESP NW AREAS. WARMING CONDITIONS CAN BE EXPECTED TUE-THUR
MOST AREAS. HOWEVER...NW AREAS MAY SEE THE START OF A COOLING TREND
THUR AS THE NEXT COLD FRONT SHIFTS SE INTO THE REGION.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 506 AM MDT FRI AUG 29 2014

MVFR CONDITIONS IN PATCHY FOG AND STRATUS WILL WANE OVER WESTERN
SOUTH DAKOTA THIS MORNING. A BAND OF ISOLATED TO SCATTERED SHOWERS
WILL MOVE EAST ACROSS NORTHEASTERN WYOMING AND INTO WESTERN SD
THIS MORNING AS AN UPPER LEVEL IMPULSE PUSHES EAST INTO THE
REGION. AN ISOLD MORNING TS IS ALSO POSSIBLE IN NE WY. THIS SAME
IMPULSE WILL SUPPORT ADDITIONAL CHANCES FOR SHRA/TS THIS AFTERNOON
WITH DIURNAL HEATING...MAINLY WESTERN AND CENTRAL SD. LOCAL MVFR
CONDS WILL BE POSSIBLE WITH ANY SHRA/TS THIS AFTERNOON.
OTHERWISE...VFR CONDITIONS WILL PREVAIL.

&&

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

$$

SHORT TERM...13
LONG TERM...JC
AVIATION...JC







000
FXUS63 KUNR 291123
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
523 AM MDT FRI AUG 29 2014

.SHORT TERM...TODAY THROUGH SATURDAY NIGHT
ISSUED AT 251 AM MDT FRI AUG 29 2014

STRONG SHORTWAVE TROUGH IS CROSSING THE CENTRAL PLAINS INTO THE ERN
DAKOTAS TO UPPER MIDWEST. ZONAL FLOW SITS ACROSS THE WRN CONUS WITH
A MUCH WEAK SHORTWAVE CROSS CNTRL/ERN MT. SURROUNDING RADAR SITES
SHOWING -SHRA/TSRA CROSSING ERN MT TO NRN WY. A SURFACE COLD FRONT
ALSO ASSOCIATED WITH THE WAVE/PRECIP IS SLIDING SE AND IS VISIBLE ON
THE BIS/BYZ RADARS.

COLD FRONT/UPPER WAVE WILL QUICKLY PUSH THROUGH THE CWA TODAY
BRINGING CHANCES FOR -SHRA/TSRA. LATEST TIMING APPEARS TO HAVE THE
AREA OF PRECIP OVER THE BLKHLS AREA BY LATE MORNING...THE CONTINUING
EWD INTO THE WRN SD PLAINS THROUGH THE AFTERNOON. STRONG INSTABILITY
DEVELOPING AHEAD OF THE FRONT OVER WRN/CNTRL SD PLAINS COULD RESULT
IN SOME STRONG STORMS THIS AFTERNOON...BUT SHEAR WILL BE QUITE WEAK
SO STORM BEHAVIOR IS EXPECTED TO BE MORE PULSE LIKE. TEMPS WILL
RANGE FROM THE MID 70S TO MID 80S...WITH COOLER TEMPS OVER NW SD/NE
WY WHERE THE FROPA OCCURS EARLIER THIS MORNING. WINDS IMMEDIATELY
BEHIND THE FRONTAL BOUNDARY WILL BECOME BREEZY...WITH GUSTS TO
AROUND 30KT...BUT WILL BE LIMITED TO AN HOUR OR TWO AFTER THE FRONT
PASSES.

WEAK RIDGING BUILDS BEHIND THE DEPARTING WAVE TONIGHT CLEARING OUT
PRECIP LATE TNGT TO SATURDAY MRNG. THE NEXT LONGWAVE TROUGH WILL
CROSS THE PACIFIC NW TO NRN ROCKIES SATURDAY...WITH ACTIVE SW FLOW
DEVELOPING. CHANCES FOR SHRA/TSRA WILL AGAIN RETURN SAT AFTN/EVNG.
GOOD INSTABILITY AND STRONG LL SHEAR OVER NW SD WILL RESULT IN
STRONG TO SEVERE TSRA SAT AFTN/EVNG. LARGE HAIL AND DAMAGING WINDS
ARE THE MAIN THREATS.

&&

.LONG TERM...SUNDAY THROUGH THURSDAY
ISSUED AT 251 AM MDT FRI AUG 29 2014

ACTIVE/PROGRESSIVE NORTHERN STREAM FLOW WILL CONTINUE THROUGH THE
PERIOD WITH A STRONG UPPER LEVEL TROUGH ON TRACK TO ADVECT THROUGH
THE REGION SUN...WITH A WEAKER SHORTWAVE IMPULSE LIKELY MONDAY.
TROUGH RELOADING OVER THE NE PAC TUE-WED FAVORED IN ECMWF/GFS/GEM
SOLUTIONS TUE...WHICH WILL SUPPORT SHORTWAVE RIDGING OVER THE
NORTHERN PLAINS WITH DRY AND WARMER CONDITIONS TUE-WED. NO SIG
CHANGES FROM THE PREVIOUS FORECAST GIVEN VERY GOOD DETERMINISTIC
MODEL CONSISTENCY AND CONTINUITY THROUGH THE PERIOD...WHICH IS IN
LINE WITH GEFS/NAEFS MEANS.

UPPER LEVEL TROUGH WILL BE IN THE PROCESS OF SHIFTING EAST ACROSS
THE NORTHERN PLAINS SUNDAY. ASSOCIATED MID LEVEL COLD POOL WILL
SUPPORT STEEP LL LAPSE RATES OVER THE FA WITH RESIDUAL LL MOISTURE
IN PLACE. DIURNAL HEATING COUPLED WITH BH/NE WY TERRAIN INFLUENCES
SHOULD SUPPORT SCT TO ISOLD SHRA/TS ESP SOUTH HALF OF THE FA.
REMAINED CLOSE TO PREVIOUS POP NUMBERS WITH MID RANGE CHANCE
COVERING PRECIP CONCERNS. OTHERWISE...A WEAKER WESTERLY FLOW IMPULSE
STILL INDICATED IN FORECAST MODELS MONDAY...POSSIBLY SUPPORTING A
FEW SHRA/TS...ALTHOUGH DRY PROFILES WILL LIMIT QPF AND
COVERAGE...ESP AWAY FROM THE BH. DRY CONDS EXPECTED TUE-WED WITH
MEAN DEEP LAYER RIDGING. THE NEXT NE PAC UPPER LEVEL TROUGH WILL
EJECT EAST INTO THE NORTHERN PLAINS WED NIGHT INTO
THUR...INTERACTING WITH A LEE SIDE TROUGH. INCREASING LSA WED NIGHT
THROUGH THUR WILL SUPPORT INCREASING CHANCES FOR SHRA/TS...FAR NW
SAT NIGHT WITH POPS TRENDING SOUTH THROUGH THUR AS THE UPPER TROUGH
SHIFTS EAST WITH THE REFLECTED SFC WAVE. DID BUMP POPS UP TO LOW
CHANCE NW 2/3 THUR NIGHT.

COOL/BELOW NORMAL TEMPS /5-10 DEGREES/ EXPECTED SUNDAY THROUGH
MONDAY...ESP NW AREAS. WARMING CONDITIONS CAN BE EXPECTED TUE-THUR
MOST AREAS. HOWEVER...NW AREAS MAY SEE THE START OF A COOLING TREND
THUR AS THE NEXT COLD FRONT SHIFTS SE INTO THE REGION.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 506 AM MDT FRI AUG 29 2014

MVFR CONDITIONS IN PATCHY FOG AND STRATUS WILL WANE OVER WESTERN
SOUTH DAKOTA THIS MORNING. A BAND OF ISOLATED TO SCATTERED SHOWERS
WILL MOVE EAST ACROSS NORTHEASTERN WYOMING AND INTO WESTERN SD
THIS MORNING AS AN UPPER LEVEL IMPULSE PUSHES EAST INTO THE
REGION. AN ISOLD MORNING TS IS ALSO POSSIBLE IN NE WY. THIS SAME
IMPULSE WILL SUPPORT ADDITIONAL CHANCES FOR SHRA/TS THIS AFTERNOON
WITH DIURNAL HEATING...MAINLY WESTERN AND CENTRAL SD. LOCAL MVFR
CONDS WILL BE POSSIBLE WITH ANY SHRA/TS THIS AFTERNOON.
OTHERWISE...VFR CONDITIONS WILL PREVAIL.

&&

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

$$

SHORT TERM...13
LONG TERM...JC
AVIATION...JC







000
FXUS63 KUNR 291123
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
523 AM MDT FRI AUG 29 2014

.SHORT TERM...TODAY THROUGH SATURDAY NIGHT
ISSUED AT 251 AM MDT FRI AUG 29 2014

STRONG SHORTWAVE TROUGH IS CROSSING THE CENTRAL PLAINS INTO THE ERN
DAKOTAS TO UPPER MIDWEST. ZONAL FLOW SITS ACROSS THE WRN CONUS WITH
A MUCH WEAK SHORTWAVE CROSS CNTRL/ERN MT. SURROUNDING RADAR SITES
SHOWING -SHRA/TSRA CROSSING ERN MT TO NRN WY. A SURFACE COLD FRONT
ALSO ASSOCIATED WITH THE WAVE/PRECIP IS SLIDING SE AND IS VISIBLE ON
THE BIS/BYZ RADARS.

COLD FRONT/UPPER WAVE WILL QUICKLY PUSH THROUGH THE CWA TODAY
BRINGING CHANCES FOR -SHRA/TSRA. LATEST TIMING APPEARS TO HAVE THE
AREA OF PRECIP OVER THE BLKHLS AREA BY LATE MORNING...THE CONTINUING
EWD INTO THE WRN SD PLAINS THROUGH THE AFTERNOON. STRONG INSTABILITY
DEVELOPING AHEAD OF THE FRONT OVER WRN/CNTRL SD PLAINS COULD RESULT
IN SOME STRONG STORMS THIS AFTERNOON...BUT SHEAR WILL BE QUITE WEAK
SO STORM BEHAVIOR IS EXPECTED TO BE MORE PULSE LIKE. TEMPS WILL
RANGE FROM THE MID 70S TO MID 80S...WITH COOLER TEMPS OVER NW SD/NE
WY WHERE THE FROPA OCCURS EARLIER THIS MORNING. WINDS IMMEDIATELY
BEHIND THE FRONTAL BOUNDARY WILL BECOME BREEZY...WITH GUSTS TO
AROUND 30KT...BUT WILL BE LIMITED TO AN HOUR OR TWO AFTER THE FRONT
PASSES.

WEAK RIDGING BUILDS BEHIND THE DEPARTING WAVE TONIGHT CLEARING OUT
PRECIP LATE TNGT TO SATURDAY MRNG. THE NEXT LONGWAVE TROUGH WILL
CROSS THE PACIFIC NW TO NRN ROCKIES SATURDAY...WITH ACTIVE SW FLOW
DEVELOPING. CHANCES FOR SHRA/TSRA WILL AGAIN RETURN SAT AFTN/EVNG.
GOOD INSTABILITY AND STRONG LL SHEAR OVER NW SD WILL RESULT IN
STRONG TO SEVERE TSRA SAT AFTN/EVNG. LARGE HAIL AND DAMAGING WINDS
ARE THE MAIN THREATS.

&&

.LONG TERM...SUNDAY THROUGH THURSDAY
ISSUED AT 251 AM MDT FRI AUG 29 2014

ACTIVE/PROGRESSIVE NORTHERN STREAM FLOW WILL CONTINUE THROUGH THE
PERIOD WITH A STRONG UPPER LEVEL TROUGH ON TRACK TO ADVECT THROUGH
THE REGION SUN...WITH A WEAKER SHORTWAVE IMPULSE LIKELY MONDAY.
TROUGH RELOADING OVER THE NE PAC TUE-WED FAVORED IN ECMWF/GFS/GEM
SOLUTIONS TUE...WHICH WILL SUPPORT SHORTWAVE RIDGING OVER THE
NORTHERN PLAINS WITH DRY AND WARMER CONDITIONS TUE-WED. NO SIG
CHANGES FROM THE PREVIOUS FORECAST GIVEN VERY GOOD DETERMINISTIC
MODEL CONSISTENCY AND CONTINUITY THROUGH THE PERIOD...WHICH IS IN
LINE WITH GEFS/NAEFS MEANS.

UPPER LEVEL TROUGH WILL BE IN THE PROCESS OF SHIFTING EAST ACROSS
THE NORTHERN PLAINS SUNDAY. ASSOCIATED MID LEVEL COLD POOL WILL
SUPPORT STEEP LL LAPSE RATES OVER THE FA WITH RESIDUAL LL MOISTURE
IN PLACE. DIURNAL HEATING COUPLED WITH BH/NE WY TERRAIN INFLUENCES
SHOULD SUPPORT SCT TO ISOLD SHRA/TS ESP SOUTH HALF OF THE FA.
REMAINED CLOSE TO PREVIOUS POP NUMBERS WITH MID RANGE CHANCE
COVERING PRECIP CONCERNS. OTHERWISE...A WEAKER WESTERLY FLOW IMPULSE
STILL INDICATED IN FORECAST MODELS MONDAY...POSSIBLY SUPPORTING A
FEW SHRA/TS...ALTHOUGH DRY PROFILES WILL LIMIT QPF AND
COVERAGE...ESP AWAY FROM THE BH. DRY CONDS EXPECTED TUE-WED WITH
MEAN DEEP LAYER RIDGING. THE NEXT NE PAC UPPER LEVEL TROUGH WILL
EJECT EAST INTO THE NORTHERN PLAINS WED NIGHT INTO
THUR...INTERACTING WITH A LEE SIDE TROUGH. INCREASING LSA WED NIGHT
THROUGH THUR WILL SUPPORT INCREASING CHANCES FOR SHRA/TS...FAR NW
SAT NIGHT WITH POPS TRENDING SOUTH THROUGH THUR AS THE UPPER TROUGH
SHIFTS EAST WITH THE REFLECTED SFC WAVE. DID BUMP POPS UP TO LOW
CHANCE NW 2/3 THUR NIGHT.

COOL/BELOW NORMAL TEMPS /5-10 DEGREES/ EXPECTED SUNDAY THROUGH
MONDAY...ESP NW AREAS. WARMING CONDITIONS CAN BE EXPECTED TUE-THUR
MOST AREAS. HOWEVER...NW AREAS MAY SEE THE START OF A COOLING TREND
THUR AS THE NEXT COLD FRONT SHIFTS SE INTO THE REGION.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 506 AM MDT FRI AUG 29 2014

MVFR CONDITIONS IN PATCHY FOG AND STRATUS WILL WANE OVER WESTERN
SOUTH DAKOTA THIS MORNING. A BAND OF ISOLATED TO SCATTERED SHOWERS
WILL MOVE EAST ACROSS NORTHEASTERN WYOMING AND INTO WESTERN SD
THIS MORNING AS AN UPPER LEVEL IMPULSE PUSHES EAST INTO THE
REGION. AN ISOLD MORNING TS IS ALSO POSSIBLE IN NE WY. THIS SAME
IMPULSE WILL SUPPORT ADDITIONAL CHANCES FOR SHRA/TS THIS AFTERNOON
WITH DIURNAL HEATING...MAINLY WESTERN AND CENTRAL SD. LOCAL MVFR
CONDS WILL BE POSSIBLE WITH ANY SHRA/TS THIS AFTERNOON.
OTHERWISE...VFR CONDITIONS WILL PREVAIL.

&&

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

$$

SHORT TERM...13
LONG TERM...JC
AVIATION...JC







000
FXUS65 KCYS 291035
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
435 AM MDT FRI AUG 29 2014

.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 430 AM MDT FRI AUG 29 2014

UPPER TROUGH RESPONSIBLE FOR THE COOL AND UNSETTLED WEATHER THE PAST
FEW DAYS WAS LOCATED OVER THE GREAT PLAINS SLOWLY PROGRESSING EAST.
A TRANSITORY SHORTWAVE RIDGE ON ITS HEELS WAS PROVIDING A DRIER
NORTHWEST FLOW ALOFT ACROSS THE CWA. THE NEXT WEATHER MAKER WAS A
SHORTWAVE TROUGH MOVING THROUGH CENTRAL MT AND NORTHWEST WY ACCOMPANIED
BY SCATTERED SHOWERS AND ISOLATED TSTORMS. A WEAK SURFACE RIDGE DOMINATED
THE CWA... WITH A COLD FRONT LOCATED FROM NORTHWEST ND TO WEST CENTRAL
MT. WINDS WERE LIGHT WITH TEMP/DEW POINT SPREADS OF A FEW DEGREES OVER
WESTERN NE. COULD SEE SOME PATCHY FOG DEVELOP BY SUNRISE IN THESE AREAS.

GREAT PLAINS TROUGH CONTINUES ITS EASTWARD TREK TOWARD THE MS VALLEY
THROUGH SATURDAY. MEANWHILE...THE SHORTWAVE TO THE NORTH MAKES A
BEELINE FOR THE NORTHERN GREAT PLAINS AND UPPER MIDWEST. A UPPER RIDGE
WEST OF THE CONTINENTAL DIVIDE SLIDES QUICKLY EAST INTO THE NORTHERN
AND CENTRAL GREAT PLAINS SATURDAY AS THE NEXT PACIFIC TROUGH BROADENS
WITH ITS AXIS OVER THE FRONT RANGE BY MIDDAY SUNDAY.

TODAY WILL BE DRIER AND WARMER. ISOLATED AFTERNOON CONVECTION WILL DEVELOP
OVER AND EAST OF THE MOUNTAINS WHERE SBCAPES RANGE FROM 400-800 J/KG.
MAIN THREATS WITH THE TSTORMS WILL BE LIGHTNING AND GUSTY WINDS. MODEL
QPFS GENERALLY AVERAGE FROM 0.10-0.25 INCH. 700MB TEMPERATURES WILL
BE ABOUT 5 DEGREES WARMER THIS AFTERNOON WITH HIGHS IN THE UPPER 70S
TO MIDDLE 80S FOR THE PLAINS. CONVECTION MAY LINGER THROUGH THE EARLY
EVENING FOR THE SOUTHEAST WY MOUNTAINS.

SATURDAY MORNING WILL BE DRY TO START WITH WARMER AND BREEZY CONDITIONS
THROUGHOUT THE DAY IN ADVANCE OF THE PACIFIC COLD FRONT AND TROUGH.
HIGH TEMPERATURES WILL RISE INTO THE 80S TO LOWER 90S FOR THE PLAINS.
PACIFIC MOISTURE WILL SPREAD EAST ACROSS WY SATURDAY AFTERNOON AND
WESTERN NE SATURDAY EVENING. INSTABILITY INCREASES EAST OF THE LARAMIE
RANGE WITH SBCAPES OF 800-1200 J/KG. EXPECT ISOLATED TO SCATTERED
TSTORM COVERAGE. BESIDE THE WIND AND LIGHTNING THREATS...LOCALLY HEAVY
RAINFALL WILL BE A POSSIBILITY. CONVECTION WILL LIKELY CONTINUE INTO
THE LATE NIGHT HOURS AS SHORTWAVE ENERGY PRECEDING THE TROUGH PASSES
THROUGH.

SUNDAY WILL BEGIN UNSETTLED WITH SCATTERED SHOWERS/TSTORMS ACCOMPANYING
THE TROUGH...AND TAPERING OFF FROM WEST TO EAST DURING THE AFTERNOON
WITH PASSAGE OF THE COLD FRONT. IT WILL TURN BREEZY AND MUCH COOLER
/10-15 DEGREES/ IN THE AFTERNOON WITH HIGHS IN THE 50S AND 60S WEST...
70S EAST.

.LONG TERM...(SUNDAY NIGHT THROUGH THURSDAY)
ISSUED AT 325 AM MDT FRI AUG 29 2014

MEDIUM AND LONG RANGE MODELS ARE IN FAIR AGREEMENT THROUGH NEXT WEEK.
EXPECT A DRIER AND WARMER PATTERN COMPARED TO THE LAST FEW WEEKS AS
THE SOUTHWEST MONSOON IS SHOWING SIGNS OF COMING TO AN END. OUTSIDE
OF A FEW SHOWERS AND TSTORMS ON MONDAY AS A WEAK DISTURBANCE QUICKLY
MOVES EASTWARD OVER THE AREA...TUESDAY THROUGH THURSDAY WILL LIKELY
BE DRY WITH TEMPERATURES ABOVE NORMAL. HIGHS IN THE 80S TO AROUND
90 WILL BE COMMON ACROSS THE HIGH PLAINS...WITH THE HIGHER VALLEYS
REMAINING IN THE UPPER 70S TO AROUND 80. MODELS INDICATE A PERIOD
OF TRANSITION IN THE OVERALL LONG WAVE PATTERN AS THE POLAR JET
STREAM BECOMES MORE DEFINED AND MORE ACTIVE BY THE MIDDLE OF THE
WEEK NEAR THE CANADIAN BORDER.

BY LATE NEXT WEEK...MODELS SHOW AN UPPER LEVEL TROUGH STALLING OVER
THE PACIFIC NORTHWEST. HIGH PRESSURE ALOFT WILL BUILD OVER THE SOUTH
CENTRAL UNITED STATES AS SOME SUBTROPICAL MOISTURE BEGINS TO ADVECT
NORTHWARD OVER THE CENTRAL ROCKY MOUNTAINS. ADDED A SLIGHT CHANCE OF
SHOWERS AND TSTORMS TO THE FORECAST BY LATE THURSDAY NIGHT AND INTO
FRIDAY WITH THE GFS AND ECMWF SHOWING SOME ORGANIZED CONVECTION OVER
THE FORECAST AREA.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY NIGHT)
ISSUED AT 207 AM MDT FRI AUG 29 2014

VFR CONDITIONS WILL PREVAIL TODAY AS SURFACE WINDS WILL SHIFT INTO THE
NORTH...BUT WILL BE RATHER LIGHT THROUGH THE DAY. ISOLATED SHOWERS AND
TSTORMS ARE EXPECTED BY THIS AFTERNOON...MAINLY EAST OF THE LARAMIE
RANGE.

&&

.FIRE WEATHER...
ISSUED AT 317 AM MDT FRI AUG 29 2014

TODAY WILL BE DRIER AND WARMER THAN THE PAST FEW DAYS. A UPPER LEVEL
DISTURBANCE WILL ADVANCE EAST FROM MONTANA AND NORTHERN WYOMING TO THE
DAKOTAS BY THIS EVENING. A COLD FRONT WILL MOVE SOUTH THROUGH EAST
CENTRAL WYOMING THIS EVENING THEN EAST AS A WARM FRONT SATURDAY. THERE
WILL BE A SLIGHT CHANCE OF AFTERNOON THUNDERSTORMS TODAY...MAINLY ALONG
AND EAST OF THE LARAMIE RANGE. GUSTY WEST TO SOUTHWEST WINDS WILL DEVELOP
SATURDAY IN ADVANCE OF A PACIFIC FRONT AND TROUGH. CHANCES FOR THUNDERSTORMS
WILL INCREASE SATURDAY AFTERNOON AND CONTINUE SUNDAY FOLLOWING THE PASSAGE
OF THE FRONT. AFTER A WARM SATURDAY...SUNDAY WILL BE MUCH COOLER. ANOTHER
DISTURBANCE WILL MOVE THROUGH THE DISTRICTS LABOR DAY BRINGING A SLIGHT
CHANCE OF AFTERNOON THUNDERSTORMS ALONG AND EAST OF THE MOUNTAINS. IT
WILL TREND DRIER AND WARMER FOR THE MIDDLE OF NEXT WEEK.

&&

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

$$

SHORT TERM...JAMSKI
LONG TERM...TJT
AVIATION...TJT
FIRE WEATHER...JAMSKI







000
FXUS65 KCYS 291035
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
435 AM MDT FRI AUG 29 2014

.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 430 AM MDT FRI AUG 29 2014

UPPER TROUGH RESPONSIBLE FOR THE COOL AND UNSETTLED WEATHER THE PAST
FEW DAYS WAS LOCATED OVER THE GREAT PLAINS SLOWLY PROGRESSING EAST.
A TRANSITORY SHORTWAVE RIDGE ON ITS HEELS WAS PROVIDING A DRIER
NORTHWEST FLOW ALOFT ACROSS THE CWA. THE NEXT WEATHER MAKER WAS A
SHORTWAVE TROUGH MOVING THROUGH CENTRAL MT AND NORTHWEST WY ACCOMPANIED
BY SCATTERED SHOWERS AND ISOLATED TSTORMS. A WEAK SURFACE RIDGE DOMINATED
THE CWA... WITH A COLD FRONT LOCATED FROM NORTHWEST ND TO WEST CENTRAL
MT. WINDS WERE LIGHT WITH TEMP/DEW POINT SPREADS OF A FEW DEGREES OVER
WESTERN NE. COULD SEE SOME PATCHY FOG DEVELOP BY SUNRISE IN THESE AREAS.

GREAT PLAINS TROUGH CONTINUES ITS EASTWARD TREK TOWARD THE MS VALLEY
THROUGH SATURDAY. MEANWHILE...THE SHORTWAVE TO THE NORTH MAKES A
BEELINE FOR THE NORTHERN GREAT PLAINS AND UPPER MIDWEST. A UPPER RIDGE
WEST OF THE CONTINENTAL DIVIDE SLIDES QUICKLY EAST INTO THE NORTHERN
AND CENTRAL GREAT PLAINS SATURDAY AS THE NEXT PACIFIC TROUGH BROADENS
WITH ITS AXIS OVER THE FRONT RANGE BY MIDDAY SUNDAY.

TODAY WILL BE DRIER AND WARMER. ISOLATED AFTERNOON CONVECTION WILL DEVELOP
OVER AND EAST OF THE MOUNTAINS WHERE SBCAPES RANGE FROM 400-800 J/KG.
MAIN THREATS WITH THE TSTORMS WILL BE LIGHTNING AND GUSTY WINDS. MODEL
QPFS GENERALLY AVERAGE FROM 0.10-0.25 INCH. 700MB TEMPERATURES WILL
BE ABOUT 5 DEGREES WARMER THIS AFTERNOON WITH HIGHS IN THE UPPER 70S
TO MIDDLE 80S FOR THE PLAINS. CONVECTION MAY LINGER THROUGH THE EARLY
EVENING FOR THE SOUTHEAST WY MOUNTAINS.

SATURDAY MORNING WILL BE DRY TO START WITH WARMER AND BREEZY CONDITIONS
THROUGHOUT THE DAY IN ADVANCE OF THE PACIFIC COLD FRONT AND TROUGH.
HIGH TEMPERATURES WILL RISE INTO THE 80S TO LOWER 90S FOR THE PLAINS.
PACIFIC MOISTURE WILL SPREAD EAST ACROSS WY SATURDAY AFTERNOON AND
WESTERN NE SATURDAY EVENING. INSTABILITY INCREASES EAST OF THE LARAMIE
RANGE WITH SBCAPES OF 800-1200 J/KG. EXPECT ISOLATED TO SCATTERED
TSTORM COVERAGE. BESIDE THE WIND AND LIGHTNING THREATS...LOCALLY HEAVY
RAINFALL WILL BE A POSSIBILITY. CONVECTION WILL LIKELY CONTINUE INTO
THE LATE NIGHT HOURS AS SHORTWAVE ENERGY PRECEDING THE TROUGH PASSES
THROUGH.

SUNDAY WILL BEGIN UNSETTLED WITH SCATTERED SHOWERS/TSTORMS ACCOMPANYING
THE TROUGH...AND TAPERING OFF FROM WEST TO EAST DURING THE AFTERNOON
WITH PASSAGE OF THE COLD FRONT. IT WILL TURN BREEZY AND MUCH COOLER
/10-15 DEGREES/ IN THE AFTERNOON WITH HIGHS IN THE 50S AND 60S WEST...
70S EAST.

.LONG TERM...(SUNDAY NIGHT THROUGH THURSDAY)
ISSUED AT 325 AM MDT FRI AUG 29 2014

MEDIUM AND LONG RANGE MODELS ARE IN FAIR AGREEMENT THROUGH NEXT WEEK.
EXPECT A DRIER AND WARMER PATTERN COMPARED TO THE LAST FEW WEEKS AS
THE SOUTHWEST MONSOON IS SHOWING SIGNS OF COMING TO AN END. OUTSIDE
OF A FEW SHOWERS AND TSTORMS ON MONDAY AS A WEAK DISTURBANCE QUICKLY
MOVES EASTWARD OVER THE AREA...TUESDAY THROUGH THURSDAY WILL LIKELY
BE DRY WITH TEMPERATURES ABOVE NORMAL. HIGHS IN THE 80S TO AROUND
90 WILL BE COMMON ACROSS THE HIGH PLAINS...WITH THE HIGHER VALLEYS
REMAINING IN THE UPPER 70S TO AROUND 80. MODELS INDICATE A PERIOD
OF TRANSITION IN THE OVERALL LONG WAVE PATTERN AS THE POLAR JET
STREAM BECOMES MORE DEFINED AND MORE ACTIVE BY THE MIDDLE OF THE
WEEK NEAR THE CANADIAN BORDER.

BY LATE NEXT WEEK...MODELS SHOW AN UPPER LEVEL TROUGH STALLING OVER
THE PACIFIC NORTHWEST. HIGH PRESSURE ALOFT WILL BUILD OVER THE SOUTH
CENTRAL UNITED STATES AS SOME SUBTROPICAL MOISTURE BEGINS TO ADVECT
NORTHWARD OVER THE CENTRAL ROCKY MOUNTAINS. ADDED A SLIGHT CHANCE OF
SHOWERS AND TSTORMS TO THE FORECAST BY LATE THURSDAY NIGHT AND INTO
FRIDAY WITH THE GFS AND ECMWF SHOWING SOME ORGANIZED CONVECTION OVER
THE FORECAST AREA.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY NIGHT)
ISSUED AT 207 AM MDT FRI AUG 29 2014

VFR CONDITIONS WILL PREVAIL TODAY AS SURFACE WINDS WILL SHIFT INTO THE
NORTH...BUT WILL BE RATHER LIGHT THROUGH THE DAY. ISOLATED SHOWERS AND
TSTORMS ARE EXPECTED BY THIS AFTERNOON...MAINLY EAST OF THE LARAMIE
RANGE.

&&

.FIRE WEATHER...
ISSUED AT 317 AM MDT FRI AUG 29 2014

TODAY WILL BE DRIER AND WARMER THAN THE PAST FEW DAYS. A UPPER LEVEL
DISTURBANCE WILL ADVANCE EAST FROM MONTANA AND NORTHERN WYOMING TO THE
DAKOTAS BY THIS EVENING. A COLD FRONT WILL MOVE SOUTH THROUGH EAST
CENTRAL WYOMING THIS EVENING THEN EAST AS A WARM FRONT SATURDAY. THERE
WILL BE A SLIGHT CHANCE OF AFTERNOON THUNDERSTORMS TODAY...MAINLY ALONG
AND EAST OF THE LARAMIE RANGE. GUSTY WEST TO SOUTHWEST WINDS WILL DEVELOP
SATURDAY IN ADVANCE OF A PACIFIC FRONT AND TROUGH. CHANCES FOR THUNDERSTORMS
WILL INCREASE SATURDAY AFTERNOON AND CONTINUE SUNDAY FOLLOWING THE PASSAGE
OF THE FRONT. AFTER A WARM SATURDAY...SUNDAY WILL BE MUCH COOLER. ANOTHER
DISTURBANCE WILL MOVE THROUGH THE DISTRICTS LABOR DAY BRINGING A SLIGHT
CHANCE OF AFTERNOON THUNDERSTORMS ALONG AND EAST OF THE MOUNTAINS. IT
WILL TREND DRIER AND WARMER FOR THE MIDDLE OF NEXT WEEK.

&&

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

$$

SHORT TERM...JAMSKI
LONG TERM...TJT
AVIATION...TJT
FIRE WEATHER...JAMSKI





  [top]

000
FXUS65 KRIW 290934
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
334 AM MDT FRI AUG 29 2014

.SHORT TERM...TODAY THROUGH SUNDAY NIGHT

A FAIRLY POTENT SHORT WAVE IS KEEPING SOME CONVECTION GOING INTO THE
EARLY MORNING HOURS...THIS WAVE WILL CONTINUE TO TREK EAST AT
A FAIRLY QUICK PACE...EXITING OUR FORECAST AREA AND INTO EASTERN
WYOMING AROUND NOON. THERE WILL BE SOME RIDGING BEHIND THE TROUGH
WITH A WEAK SHORT WAVE ROTATING ATOP THE RIDGE...MAINLY AFFECTING
MONTANA BUT SUPPLYING SOME BROAD LIFT TO THE NORTHERN ZONES...THIS
IN CONJUNCTION WITH A COLD FRONT LEFT BEHIND BY THE OVERNIGHT SYSTEM
WILL SUPPLY SOME CHANCE FOR A SHOWER OR THUNDERSTORM ACROSS THE
NORTHERN HALF OF THE FORECAST AREA. INSTABILITY IS RATHER MODEST BUT
SHEAR ACROSS THE NORTHERN HALF OF THE STATE SHOULD BE ENOUGH TO
SUSTAIN SOME OF THE STORMS THAT POP UP OVER THE HIGHER TERRAIN LONG
ENOUGH TO CARRY THEM INTO THE ADJACENT FOOTHILLS AND BASINS.

THERE WILL BE A BREAK IN THE...RELATIVELY TAME...ACTION THIS EVENING
AHEAD OF THE NEXT SHORT WAVE THAT COULD BEGIN TO BRING THE NEXT WAVE
OF PRECIPITATION INTO THE WEST AS EARLY AS 12Z SATURDAY. THE LATEST
MODEL RUNS HAVE STARTED BRINGING IN THIS WAVE A LITTLE SLOWER...BUT
KEPT PREVIOUS SLIGHT CHANCE POPS TO COVER THE UNCERTAINTIES IN
TIMING.

THE BULK OF THE ENERGY FROM THIS BROAD...DYNAMIC DIGGING TROUGH WILL
ARRIVE DURING THE DAY ON SATURDAY. THERE WILL BE PLENTY OF DYNAMIC
FORCING ALOFT TO SUPPORT SCATTERED TO NUMEROUS SHOWERS WITH SOME
EMBEDDED THUNDER DURING THE AFTERNOON WITH SOME STRONGER STORMS
CAPABLE OF PRODUCING MARGINAL HAIL...STRONG GUSTY WINDS AND SOME
TORRENTIAL DOWNPOURS LATER IN THE AFTERNOON AND INTO THE EVENING.
ACROSS THE SOUTH...AHEAD OF THE SURFACE COLD FRONT...THERE COULD BE
SOME ELEVATED FIRE CONCERNS AS THE STRONG SOUTHWEST WIND ALOFT WILL
EASILY MIX DOWN TO THE SURFACE DURING THE DAY WITH GUSTS TO 50 MPH
POSSIBLE ACROSS SWEETWATER COUNTY AND POSSIBLY UP INTO EASTERN
FREMONT AND NATRONA COUNTIES...HOWEVER THE RELATIVE HUMIDITY WILL BE
MARGINALLY LOW...LIKELY ONLY DIPPING INTO THE UPPER TEENS DURING THE
DAY. HOWEVER...THE AIR AT THE SURFACE WILL BE DRY ENOUGH ACROSS THE
SOUTH...COMBINED WITH THE SWIFT UNIDIRECTIONAL SPEED SHEAR ALOFT...
TO ELEVATE THE HIGH WIND THREAT WITH ANY STORMS THAT DO FORM IN THIS
AREA.

SUNDAY...THE TROF CONTINUES TO TREK EAST ACROSS THE AREA...HOW
QUICKLY DEPENDS UPON WHICH MODEL YOU BELIEVE...BUT THE EASTERN HALF
OF THE FORECAST AREA MAY STILL BE ON THE MORE FAVORABLE FRONT END OF
THE TROUGH DURING THE AFTERNOON...WHICH COULD SUPPORT MORE
THUNDERSTORMS...WHILE OTHER SOLUTIONS PUT WESTERN AND CENTRAL
WYOMING IN THE SUBSIDENT BACK EDGE OF THE TROUGH...WHICH WOULD MAKE
FOR A MUCH QUIETER DAY ACROSS THE BOARD...SAVE A FEW GUSTY WINDS.
MUCH COOLER CONDITIONS FOR SURE...WITH CONTINUED GUSTY W TO WSW
WINDS ACROSS THE AREA WEST OF THE DIVIDE BEHIND THE EXITING SFC
FRONT.

.LONG TERM...MONDAY THROUGH FRIDAY

ON MONDAY...GFS AND GEM MODELS ARE DRIER THAN THE ECMWF ON MONDAY.
THIS IS DUE TO TIMING OF A WEATHER SYSTEM IN THE NW FLOW ALOFT. THE
ECMWF MODEL BRINGS A SYSTEM ACROSS THE AREA WHILE THE GFS/GEM ARE
WEAKER AND FASTER. FOR NOW WILL KEEP LOW CHANCE OF SHOWERS/STORMS IN
THE FORECAST WHICH MEANS LEANING TOWARD THE ECMWF TIMING. ISOLATED
EARLY EVENING SHOWERS/STORMS THEN DECREASING CLOUDS MONDAY NIGHT.
THE FLOW ALOFT TURNS WEST FOR TUESDAY AND A DRY DAY EXPECTED.
WEDNESDAY LOOKS MOSTLY DRY FOR MOST PLACES. SOME MOISTURE IS
FORECAST TO MOVE IN WED AFTERNOON WHICH WOULD LEAD TO ISOLATED
SHOWERS OR STORMS...MAINLY OVER AND NEAR THE MOUNTAINS. FLOW ALOFT
BACKS TO THE SW FOR THURSDAY AND FRIDAY. MORE MID AND HIGH LEVEL
MOISTURE IS FORECAST TO RETURN TO THE REGION...MORE SO ON FRIDAY.
IN ADDITION...A FRONTAL BOUNDARY WILL BE SLIDING SOUTH INTO
NORTHERN WY THURSDAY AFTERNOON AND IT LOOKS TO PUSH SOUTH INTO
CENTRAL WY BY FRIDAY MORNING. THEN THE BOUNDARY MAY OR MAY NOT
MOVE BACK NORTH FRIDAY PM IN THE CENTRAL ZONES...GFS SAYS
NO...ECMWF SAYS YES. THE FRONTAL BOUNDARY WILL ALSO BE A FOCUS FOR
SHOWERS AND STORMS...NOT TO MENTION THE MOISTURE RETURN FROM THE
SW. WILL KEEP THE BETTER CHANCE OF SHOWERS/STORMS IN THE NW AND
NORTH THURSDAY. THEN ISOLATED SHOWERS AND STORMS FOR MOST PLACES
NEXT FRIDAY. AS FOR HIGH TEMPS...MONDAY WILL BE MILD AND LITTLE
CHANGED FROM SUNDAY HIGHS. WARMER HIGHS FOR TUESDAY AND WEDNESDAY.
THEN COOLER FOR THE NW AND NORTH THURSDAY WITH A FEW DEGREES OF
COOLING CENTRAL AND SOUTH. HIGHS FRIDAY COOLER NORTH AND CENTRAL
WITH SLIGHT COOLING SOUTH.

&&

.AVIATION.../12Z ISSUANCE/

AN UPPER LEVEL DISTURBANCE WILL CONTINUE TO PUSH EAST ACROSS MONTANA
EARLY THIS MORNING.  SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS
ARE EXPECTED TO BE MOSTLY EAST OF THE INTERSTATE 25 CORRIDOR AFTER
12Z...BUT POSSIBLY EXTENDING SSW INTO VCNTY KCPR THROUGH AROUND 14Z.

A COUPLE OF MORE RIPPLES IN THE FLOW WILL PUSH EAST ACROSS THE
NORTHERN GREAT BASIN...ACROSS WYOMING FRIDAY AFTERNOON AND EVENING.
MAINLY ISOLATED -TSRA/-SHRA WILL OCCUR ACROSS MOST OF THE AREA WITH
POSSIBLY MORE SCT ACTIVITY OVER THE HIGH TERRAIN.  THIS ACTIVITY
WILL MOSTLY DISSIPATE SHORTLY AFTER SUNSET.  THE NEXT PACIFIC SYSTEM
WILL SPREAD MID AND HIGH CLOUDS VCNTY AND WEST OF THE DIVIDE 06Z-12Z
SATURDAY ALONG WITH ISOLD -SHRA.

&&

.FIRE WEATHER...

ANOTHER SYSTEM WILL BRING MORE ISOLATED THUNDERSTORMS ACROSS THE
NORTHERN HALF OF THE STATE. THE MAIN THREAT FROM THESE WILL BE GUSTY
WIND TO 45 MPH AND LIGHTNING. ON SATURDAY...A STRONGER COLD FRONT
WILL SWEEP EAST ACROSS THE AREA WITH INCREASING SOUTHWEST WINDS
AHEAD OF IT AND ISOLATED TO WIDELY SCATTERED THUNDERSTORMS ALONG AND
BEHIND THE COLD FRONT. FIRE WEATHER CONCERNS WILL INCREASE AHEAD OF
THE FRONT FOR A FEW HOURS AS MIN RH`S DROP INTO THE TEENS AND SW
WINDS BLOW 20 TO 35 MPH WITH FREQUENT GUSTS UP TO 50 MPH IN THE MORE
WIND PRONE AREAS. HOWEVER...ALL THE RECENT RAIN MAY HELP KEEP THE
MIN RH`S ABOVE CRITICAL LEVELS. WE WILL CONTINUE TO MONITOR.

&&

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

$$

SHORT TERM...ALLEN
LONG TERM...AR
AVIATION...AEM
FIRE WEATHER...ALLEN







000
FXUS65 KRIW 290934
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
334 AM MDT FRI AUG 29 2014

.SHORT TERM...TODAY THROUGH SUNDAY NIGHT

A FAIRLY POTENT SHORT WAVE IS KEEPING SOME CONVECTION GOING INTO THE
EARLY MORNING HOURS...THIS WAVE WILL CONTINUE TO TREK EAST AT
A FAIRLY QUICK PACE...EXITING OUR FORECAST AREA AND INTO EASTERN
WYOMING AROUND NOON. THERE WILL BE SOME RIDGING BEHIND THE TROUGH
WITH A WEAK SHORT WAVE ROTATING ATOP THE RIDGE...MAINLY AFFECTING
MONTANA BUT SUPPLYING SOME BROAD LIFT TO THE NORTHERN ZONES...THIS
IN CONJUNCTION WITH A COLD FRONT LEFT BEHIND BY THE OVERNIGHT SYSTEM
WILL SUPPLY SOME CHANCE FOR A SHOWER OR THUNDERSTORM ACROSS THE
NORTHERN HALF OF THE FORECAST AREA. INSTABILITY IS RATHER MODEST BUT
SHEAR ACROSS THE NORTHERN HALF OF THE STATE SHOULD BE ENOUGH TO
SUSTAIN SOME OF THE STORMS THAT POP UP OVER THE HIGHER TERRAIN LONG
ENOUGH TO CARRY THEM INTO THE ADJACENT FOOTHILLS AND BASINS.

THERE WILL BE A BREAK IN THE...RELATIVELY TAME...ACTION THIS EVENING
AHEAD OF THE NEXT SHORT WAVE THAT COULD BEGIN TO BRING THE NEXT WAVE
OF PRECIPITATION INTO THE WEST AS EARLY AS 12Z SATURDAY. THE LATEST
MODEL RUNS HAVE STARTED BRINGING IN THIS WAVE A LITTLE SLOWER...BUT
KEPT PREVIOUS SLIGHT CHANCE POPS TO COVER THE UNCERTAINTIES IN
TIMING.

THE BULK OF THE ENERGY FROM THIS BROAD...DYNAMIC DIGGING TROUGH WILL
ARRIVE DURING THE DAY ON SATURDAY. THERE WILL BE PLENTY OF DYNAMIC
FORCING ALOFT TO SUPPORT SCATTERED TO NUMEROUS SHOWERS WITH SOME
EMBEDDED THUNDER DURING THE AFTERNOON WITH SOME STRONGER STORMS
CAPABLE OF PRODUCING MARGINAL HAIL...STRONG GUSTY WINDS AND SOME
TORRENTIAL DOWNPOURS LATER IN THE AFTERNOON AND INTO THE EVENING.
ACROSS THE SOUTH...AHEAD OF THE SURFACE COLD FRONT...THERE COULD BE
SOME ELEVATED FIRE CONCERNS AS THE STRONG SOUTHWEST WIND ALOFT WILL
EASILY MIX DOWN TO THE SURFACE DURING THE DAY WITH GUSTS TO 50 MPH
POSSIBLE ACROSS SWEETWATER COUNTY AND POSSIBLY UP INTO EASTERN
FREMONT AND NATRONA COUNTIES...HOWEVER THE RELATIVE HUMIDITY WILL BE
MARGINALLY LOW...LIKELY ONLY DIPPING INTO THE UPPER TEENS DURING THE
DAY. HOWEVER...THE AIR AT THE SURFACE WILL BE DRY ENOUGH ACROSS THE
SOUTH...COMBINED WITH THE SWIFT UNIDIRECTIONAL SPEED SHEAR ALOFT...
TO ELEVATE THE HIGH WIND THREAT WITH ANY STORMS THAT DO FORM IN THIS
AREA.

SUNDAY...THE TROF CONTINUES TO TREK EAST ACROSS THE AREA...HOW
QUICKLY DEPENDS UPON WHICH MODEL YOU BELIEVE...BUT THE EASTERN HALF
OF THE FORECAST AREA MAY STILL BE ON THE MORE FAVORABLE FRONT END OF
THE TROUGH DURING THE AFTERNOON...WHICH COULD SUPPORT MORE
THUNDERSTORMS...WHILE OTHER SOLUTIONS PUT WESTERN AND CENTRAL
WYOMING IN THE SUBSIDENT BACK EDGE OF THE TROUGH...WHICH WOULD MAKE
FOR A MUCH QUIETER DAY ACROSS THE BOARD...SAVE A FEW GUSTY WINDS.
MUCH COOLER CONDITIONS FOR SURE...WITH CONTINUED GUSTY W TO WSW
WINDS ACROSS THE AREA WEST OF THE DIVIDE BEHIND THE EXITING SFC
FRONT.

.LONG TERM...MONDAY THROUGH FRIDAY

ON MONDAY...GFS AND GEM MODELS ARE DRIER THAN THE ECMWF ON MONDAY.
THIS IS DUE TO TIMING OF A WEATHER SYSTEM IN THE NW FLOW ALOFT. THE
ECMWF MODEL BRINGS A SYSTEM ACROSS THE AREA WHILE THE GFS/GEM ARE
WEAKER AND FASTER. FOR NOW WILL KEEP LOW CHANCE OF SHOWERS/STORMS IN
THE FORECAST WHICH MEANS LEANING TOWARD THE ECMWF TIMING. ISOLATED
EARLY EVENING SHOWERS/STORMS THEN DECREASING CLOUDS MONDAY NIGHT.
THE FLOW ALOFT TURNS WEST FOR TUESDAY AND A DRY DAY EXPECTED.
WEDNESDAY LOOKS MOSTLY DRY FOR MOST PLACES. SOME MOISTURE IS
FORECAST TO MOVE IN WED AFTERNOON WHICH WOULD LEAD TO ISOLATED
SHOWERS OR STORMS...MAINLY OVER AND NEAR THE MOUNTAINS. FLOW ALOFT
BACKS TO THE SW FOR THURSDAY AND FRIDAY. MORE MID AND HIGH LEVEL
MOISTURE IS FORECAST TO RETURN TO THE REGION...MORE SO ON FRIDAY.
IN ADDITION...A FRONTAL BOUNDARY WILL BE SLIDING SOUTH INTO
NORTHERN WY THURSDAY AFTERNOON AND IT LOOKS TO PUSH SOUTH INTO
CENTRAL WY BY FRIDAY MORNING. THEN THE BOUNDARY MAY OR MAY NOT
MOVE BACK NORTH FRIDAY PM IN THE CENTRAL ZONES...GFS SAYS
NO...ECMWF SAYS YES. THE FRONTAL BOUNDARY WILL ALSO BE A FOCUS FOR
SHOWERS AND STORMS...NOT TO MENTION THE MOISTURE RETURN FROM THE
SW. WILL KEEP THE BETTER CHANCE OF SHOWERS/STORMS IN THE NW AND
NORTH THURSDAY. THEN ISOLATED SHOWERS AND STORMS FOR MOST PLACES
NEXT FRIDAY. AS FOR HIGH TEMPS...MONDAY WILL BE MILD AND LITTLE
CHANGED FROM SUNDAY HIGHS. WARMER HIGHS FOR TUESDAY AND WEDNESDAY.
THEN COOLER FOR THE NW AND NORTH THURSDAY WITH A FEW DEGREES OF
COOLING CENTRAL AND SOUTH. HIGHS FRIDAY COOLER NORTH AND CENTRAL
WITH SLIGHT COOLING SOUTH.

&&

.AVIATION.../12Z ISSUANCE/

AN UPPER LEVEL DISTURBANCE WILL CONTINUE TO PUSH EAST ACROSS MONTANA
EARLY THIS MORNING.  SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS
ARE EXPECTED TO BE MOSTLY EAST OF THE INTERSTATE 25 CORRIDOR AFTER
12Z...BUT POSSIBLY EXTENDING SSW INTO VCNTY KCPR THROUGH AROUND 14Z.

A COUPLE OF MORE RIPPLES IN THE FLOW WILL PUSH EAST ACROSS THE
NORTHERN GREAT BASIN...ACROSS WYOMING FRIDAY AFTERNOON AND EVENING.
MAINLY ISOLATED -TSRA/-SHRA WILL OCCUR ACROSS MOST OF THE AREA WITH
POSSIBLY MORE SCT ACTIVITY OVER THE HIGH TERRAIN.  THIS ACTIVITY
WILL MOSTLY DISSIPATE SHORTLY AFTER SUNSET.  THE NEXT PACIFIC SYSTEM
WILL SPREAD MID AND HIGH CLOUDS VCNTY AND WEST OF THE DIVIDE 06Z-12Z
SATURDAY ALONG WITH ISOLD -SHRA.

&&

.FIRE WEATHER...

ANOTHER SYSTEM WILL BRING MORE ISOLATED THUNDERSTORMS ACROSS THE
NORTHERN HALF OF THE STATE. THE MAIN THREAT FROM THESE WILL BE GUSTY
WIND TO 45 MPH AND LIGHTNING. ON SATURDAY...A STRONGER COLD FRONT
WILL SWEEP EAST ACROSS THE AREA WITH INCREASING SOUTHWEST WINDS
AHEAD OF IT AND ISOLATED TO WIDELY SCATTERED THUNDERSTORMS ALONG AND
BEHIND THE COLD FRONT. FIRE WEATHER CONCERNS WILL INCREASE AHEAD OF
THE FRONT FOR A FEW HOURS AS MIN RH`S DROP INTO THE TEENS AND SW
WINDS BLOW 20 TO 35 MPH WITH FREQUENT GUSTS UP TO 50 MPH IN THE MORE
WIND PRONE AREAS. HOWEVER...ALL THE RECENT RAIN MAY HELP KEEP THE
MIN RH`S ABOVE CRITICAL LEVELS. WE WILL CONTINUE TO MONITOR.

&&

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

$$

SHORT TERM...ALLEN
LONG TERM...AR
AVIATION...AEM
FIRE WEATHER...ALLEN








000
FXUS63 KUNR 290852
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
252 AM MDT FRI AUG 29 2014

.SHORT TERM...TODAY THROUGH SATURDAY NIGHT
ISSUED AT 251 AM MDT FRI AUG 29 2014

STRONG SHORTWAVE TROUGH IS CROSSING THE CENTRAL PLAINS INTO THE ERN
DAKOTAS TO UPPER MIDWEST. ZONAL FLOW SITS ACROSS THE WRN CONUS WITH
A MUCH WEAK SHORTWAVE CROSS CNTRL/ERN MT. SURROUNDING RADAR SITES
SHOWING -SHRA/TSRA CROSSING ERN MT TO NRN WY. A SURFACE COLD FRONT
ALSO ASSOCIATED WITH THE WAVE/PRECIP IS SLIDING SE AND IS VISIBLE ON
THE BIS/BYZ RADARS.

COLD FRONT/UPPER WAVE WILL QUICKLY PUSH THROUGH THE CWA TODAY
BRINGING CHANCES FOR -SHRA/TSRA. LATEST TIMING APPEARS TO HAVE THE
AREA OF PRECIP OVER THE BLKHLS AREA BY LATE MORNING...THE CONTINUING
EWD INTO THE WRN SD PLAINS THROUGH THE AFTERNOON. STRONG INSTABILITY
DEVELOPING AHEAD OF THE FRONT OVER WRN/CNTRL SD PLAINS COULD RESULT
IN SOME STRONG STORMS THIS AFTERNOON...BUT SHEAR WILL BE QUITE WEAK
SO STORM BEHAVIOR IS EXPECTED TO BE MORE PULSE LIKE. TEMPS WILL
RANGE FROM THE MID 70S TO MID 80S...WITH COOLER TEMPS OVER NW SD/NE
WY WHERE THE FROPA OCCURS EARLIER THIS MORNING. WINDS IMMEDIATELY
BEHIND THE FRONTAL BOUNDARY WILL BECOME BREEZY...WITH GUSTS TO
AROUND 30KT...BUT WILL BE LIMITED TO AN HOUR OR TWO AFTER THE FRONT
PASSES.

WEAK RIDGING BUILDS BEHIND THE DEPARTING WAVE TONIGHT CLEARING OUT
PRECIP LATE TNGT TO SATURDAY MRNG. THE NEXT LONGWAVE TROUGH WILL
CROSS THE PACIFIC NW TO NRN ROCKIES SATURDAY...WITH ACTIVE SW FLOW
DEVELOPING. CHANCES FOR SHRA/TSRA WILL AGAIN RETURN SAT AFTN/EVNG.
GOOD INSTABILITY AND STRONG LL SHEAR OVER NW SD WILL RESULT IN
STRONG TO SEVERE TSRA SAT AFTN/EVNG. LARGE HAIL AND DAMAGING WINDS
ARE THE MAIN THREATS.

&&

.LONG TERM...SUNDAY THROUGH THURSDAY
ISSUED AT 251 AM MDT FRI AUG 29 2014

ACTIVE/PROGRESSIVE NORTHERN STREAM FLOW WILL CONTINUE THROUGH THE
PERIOD WITH A STRONG UPPER LEVEL TROUGH ON TRACK TO ADVECT THROUGH
THE REGION SUN...WITH A WEAKER SHORTWAVE IMPULSE LIKELY MONDAY.
TROUGH RELOADING OVER THE NE PAC TUE-WED FAVORED IN ECMWF/GFS/GEM
SOLUTIONS TUE...WHICH WILL SUPPORT SHORTWAVE RIDGING OVER THE
NORTHERN PLAINS WITH DRY AND WARMER CONDITIONS TUE-WED. NO SIG
CHANGES FROM THE PREVIOUS FORECAST GIVEN VERY GOOD DETERMINISTIC
MODEL CONSISTENCY AND CONTINUITY THROUGH THE PERIOD...WHICH IS IN
LINE WITH GEFS/NAEFS MEANS.

UPPER LEVEL TROUGH WILL BE IN THE PROCESS OF SHIFTING EAST ACROSS
THE NORTHERN PLAINS SUNDAY. ASSOCIATED MID LEVEL COLD POOL WILL
SUPPORT STEEP LL LAPSE RATES OVER THE FA WITH RESIDUAL LL MOISTURE
IN PLACE. DIURNAL HEATING COUPLED WITH BH/NE WY TERRAIN INFLUENCES
SHOULD SUPPORT SCT TO ISOLD SHRA/TS ESP SOUTH HALF OF THE FA.
REMAINED CLOSE TO PREVIOUS POP NUMBERS WITH MID RANGE CHANCE
COVERING PRECIP CONCERNS. OTHERWISE...A WEAKER WESTERLY FLOW IMPULSE
STILL INDICATED IN FORECAST MODELS MONDAY...POSSIBLY SUPPORTING A
FEW SHRA/TS...ALTHOUGH DRY PROFILES WILL LIMIT QPF AND
COVERAGE...ESP AWAY FROM THE BH. DRY CONDS EXPECTED TUE-WED WITH
MEAN DEEP LAYER RIDGING. THE NEXT NE PAC UPPER LEVEL TROUGH WILL
EJECT EAST INTO THE NORTHERN PLAINS WED NIGHT INTO
THUR...INTERACTING WITH A LEE SIDE TROUGH. INCREASING LSA WED NIGHT
THROUGH THUR WILL SUPPORT INCREASING CHANCES FOR SHRA/TS...FAR NW
SAT NIGHT WITH POPS TRENDING SOUTH THROUGH THUR AS THE UPPER TROUGH
SHIFTS EAST WITH THE REFLECTED SFC WAVE. DID BUMP POPS UP TO LOW
CHANCE NW 2/3 THUR NIGHT.

COOL/BELOW NORMAL TEMPS /5-10 DEGREES/ EXPECTED SUNDAY THROUGH
MONDAY...ESP NW AREAS. WARMING CONDITIONS CAN BE EXPECTED TUE-THUR
MOST AREAS. HOWEVER...NW AREAS MAY SEE THE START OF A COOLING TREND
THUR AS THE NEXT COLD FRONT SHIFTS SE INTO THE REGION.

&&

.AVIATION...FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT
ISSUED AT 251 AM MDT FRI AUG 29 2014

MVFR CONDITIONS IN PATCHY FOG MAY DEVELOP OVER PARTS OF WESTERN
SOUTH DAKOTA LATE TONIGHT/EARLY FRIDAY MORNING. A BAND OF ISOLATED
TO SCATTERED SHOWERS AND THUNDERSTORMS WILL MOVE INTO NORTHEASTERN
WYOMING LATE TONIGHT AND WILL SPREAD EASTWARD INTO WESTERN SOUTH
DAKOTA ON FRIDAY MORNING. THUNDERSTORMS WILL INCREASE IN COVERAGE
OVER WESTERN AND CENTRAL SOUTH DAKOTA ON FRIDAY AFTERNOON.

&&

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

$$

SHORT TERM...13
LONG TERM...JC
AVIATION...JC








000
FXUS63 KUNR 290852
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
252 AM MDT FRI AUG 29 2014

.SHORT TERM...TODAY THROUGH SATURDAY NIGHT
ISSUED AT 251 AM MDT FRI AUG 29 2014

STRONG SHORTWAVE TROUGH IS CROSSING THE CENTRAL PLAINS INTO THE ERN
DAKOTAS TO UPPER MIDWEST. ZONAL FLOW SITS ACROSS THE WRN CONUS WITH
A MUCH WEAK SHORTWAVE CROSS CNTRL/ERN MT. SURROUNDING RADAR SITES
SHOWING -SHRA/TSRA CROSSING ERN MT TO NRN WY. A SURFACE COLD FRONT
ALSO ASSOCIATED WITH THE WAVE/PRECIP IS SLIDING SE AND IS VISIBLE ON
THE BIS/BYZ RADARS.

COLD FRONT/UPPER WAVE WILL QUICKLY PUSH THROUGH THE CWA TODAY
BRINGING CHANCES FOR -SHRA/TSRA. LATEST TIMING APPEARS TO HAVE THE
AREA OF PRECIP OVER THE BLKHLS AREA BY LATE MORNING...THE CONTINUING
EWD INTO THE WRN SD PLAINS THROUGH THE AFTERNOON. STRONG INSTABILITY
DEVELOPING AHEAD OF THE FRONT OVER WRN/CNTRL SD PLAINS COULD RESULT
IN SOME STRONG STORMS THIS AFTERNOON...BUT SHEAR WILL BE QUITE WEAK
SO STORM BEHAVIOR IS EXPECTED TO BE MORE PULSE LIKE. TEMPS WILL
RANGE FROM THE MID 70S TO MID 80S...WITH COOLER TEMPS OVER NW SD/NE
WY WHERE THE FROPA OCCURS EARLIER THIS MORNING. WINDS IMMEDIATELY
BEHIND THE FRONTAL BOUNDARY WILL BECOME BREEZY...WITH GUSTS TO
AROUND 30KT...BUT WILL BE LIMITED TO AN HOUR OR TWO AFTER THE FRONT
PASSES.

WEAK RIDGING BUILDS BEHIND THE DEPARTING WAVE TONIGHT CLEARING OUT
PRECIP LATE TNGT TO SATURDAY MRNG. THE NEXT LONGWAVE TROUGH WILL
CROSS THE PACIFIC NW TO NRN ROCKIES SATURDAY...WITH ACTIVE SW FLOW
DEVELOPING. CHANCES FOR SHRA/TSRA WILL AGAIN RETURN SAT AFTN/EVNG.
GOOD INSTABILITY AND STRONG LL SHEAR OVER NW SD WILL RESULT IN
STRONG TO SEVERE TSRA SAT AFTN/EVNG. LARGE HAIL AND DAMAGING WINDS
ARE THE MAIN THREATS.

&&

.LONG TERM...SUNDAY THROUGH THURSDAY
ISSUED AT 251 AM MDT FRI AUG 29 2014

ACTIVE/PROGRESSIVE NORTHERN STREAM FLOW WILL CONTINUE THROUGH THE
PERIOD WITH A STRONG UPPER LEVEL TROUGH ON TRACK TO ADVECT THROUGH
THE REGION SUN...WITH A WEAKER SHORTWAVE IMPULSE LIKELY MONDAY.
TROUGH RELOADING OVER THE NE PAC TUE-WED FAVORED IN ECMWF/GFS/GEM
SOLUTIONS TUE...WHICH WILL SUPPORT SHORTWAVE RIDGING OVER THE
NORTHERN PLAINS WITH DRY AND WARMER CONDITIONS TUE-WED. NO SIG
CHANGES FROM THE PREVIOUS FORECAST GIVEN VERY GOOD DETERMINISTIC
MODEL CONSISTENCY AND CONTINUITY THROUGH THE PERIOD...WHICH IS IN
LINE WITH GEFS/NAEFS MEANS.

UPPER LEVEL TROUGH WILL BE IN THE PROCESS OF SHIFTING EAST ACROSS
THE NORTHERN PLAINS SUNDAY. ASSOCIATED MID LEVEL COLD POOL WILL
SUPPORT STEEP LL LAPSE RATES OVER THE FA WITH RESIDUAL LL MOISTURE
IN PLACE. DIURNAL HEATING COUPLED WITH BH/NE WY TERRAIN INFLUENCES
SHOULD SUPPORT SCT TO ISOLD SHRA/TS ESP SOUTH HALF OF THE FA.
REMAINED CLOSE TO PREVIOUS POP NUMBERS WITH MID RANGE CHANCE
COVERING PRECIP CONCERNS. OTHERWISE...A WEAKER WESTERLY FLOW IMPULSE
STILL INDICATED IN FORECAST MODELS MONDAY...POSSIBLY SUPPORTING A
FEW SHRA/TS...ALTHOUGH DRY PROFILES WILL LIMIT QPF AND
COVERAGE...ESP AWAY FROM THE BH. DRY CONDS EXPECTED TUE-WED WITH
MEAN DEEP LAYER RIDGING. THE NEXT NE PAC UPPER LEVEL TROUGH WILL
EJECT EAST INTO THE NORTHERN PLAINS WED NIGHT INTO
THUR...INTERACTING WITH A LEE SIDE TROUGH. INCREASING LSA WED NIGHT
THROUGH THUR WILL SUPPORT INCREASING CHANCES FOR SHRA/TS...FAR NW
SAT NIGHT WITH POPS TRENDING SOUTH THROUGH THUR AS THE UPPER TROUGH
SHIFTS EAST WITH THE REFLECTED SFC WAVE. DID BUMP POPS UP TO LOW
CHANCE NW 2/3 THUR NIGHT.

COOL/BELOW NORMAL TEMPS /5-10 DEGREES/ EXPECTED SUNDAY THROUGH
MONDAY...ESP NW AREAS. WARMING CONDITIONS CAN BE EXPECTED TUE-THUR
MOST AREAS. HOWEVER...NW AREAS MAY SEE THE START OF A COOLING TREND
THUR AS THE NEXT COLD FRONT SHIFTS SE INTO THE REGION.

&&

.AVIATION...FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT
ISSUED AT 251 AM MDT FRI AUG 29 2014

MVFR CONDITIONS IN PATCHY FOG MAY DEVELOP OVER PARTS OF WESTERN
SOUTH DAKOTA LATE TONIGHT/EARLY FRIDAY MORNING. A BAND OF ISOLATED
TO SCATTERED SHOWERS AND THUNDERSTORMS WILL MOVE INTO NORTHEASTERN
WYOMING LATE TONIGHT AND WILL SPREAD EASTWARD INTO WESTERN SOUTH
DAKOTA ON FRIDAY MORNING. THUNDERSTORMS WILL INCREASE IN COVERAGE
OVER WESTERN AND CENTRAL SOUTH DAKOTA ON FRIDAY AFTERNOON.

&&

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

$$

SHORT TERM...13
LONG TERM...JC
AVIATION...JC








000
FXUS63 KUNR 290852
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
252 AM MDT FRI AUG 29 2014

.SHORT TERM...TODAY THROUGH SATURDAY NIGHT
ISSUED AT 251 AM MDT FRI AUG 29 2014

STRONG SHORTWAVE TROUGH IS CROSSING THE CENTRAL PLAINS INTO THE ERN
DAKOTAS TO UPPER MIDWEST. ZONAL FLOW SITS ACROSS THE WRN CONUS WITH
A MUCH WEAK SHORTWAVE CROSS CNTRL/ERN MT. SURROUNDING RADAR SITES
SHOWING -SHRA/TSRA CROSSING ERN MT TO NRN WY. A SURFACE COLD FRONT
ALSO ASSOCIATED WITH THE WAVE/PRECIP IS SLIDING SE AND IS VISIBLE ON
THE BIS/BYZ RADARS.

COLD FRONT/UPPER WAVE WILL QUICKLY PUSH THROUGH THE CWA TODAY
BRINGING CHANCES FOR -SHRA/TSRA. LATEST TIMING APPEARS TO HAVE THE
AREA OF PRECIP OVER THE BLKHLS AREA BY LATE MORNING...THE CONTINUING
EWD INTO THE WRN SD PLAINS THROUGH THE AFTERNOON. STRONG INSTABILITY
DEVELOPING AHEAD OF THE FRONT OVER WRN/CNTRL SD PLAINS COULD RESULT
IN SOME STRONG STORMS THIS AFTERNOON...BUT SHEAR WILL BE QUITE WEAK
SO STORM BEHAVIOR IS EXPECTED TO BE MORE PULSE LIKE. TEMPS WILL
RANGE FROM THE MID 70S TO MID 80S...WITH COOLER TEMPS OVER NW SD/NE
WY WHERE THE FROPA OCCURS EARLIER THIS MORNING. WINDS IMMEDIATELY
BEHIND THE FRONTAL BOUNDARY WILL BECOME BREEZY...WITH GUSTS TO
AROUND 30KT...BUT WILL BE LIMITED TO AN HOUR OR TWO AFTER THE FRONT
PASSES.

WEAK RIDGING BUILDS BEHIND THE DEPARTING WAVE TONIGHT CLEARING OUT
PRECIP LATE TNGT TO SATURDAY MRNG. THE NEXT LONGWAVE TROUGH WILL
CROSS THE PACIFIC NW TO NRN ROCKIES SATURDAY...WITH ACTIVE SW FLOW
DEVELOPING. CHANCES FOR SHRA/TSRA WILL AGAIN RETURN SAT AFTN/EVNG.
GOOD INSTABILITY AND STRONG LL SHEAR OVER NW SD WILL RESULT IN
STRONG TO SEVERE TSRA SAT AFTN/EVNG. LARGE HAIL AND DAMAGING WINDS
ARE THE MAIN THREATS.

&&

.LONG TERM...SUNDAY THROUGH THURSDAY
ISSUED AT 251 AM MDT FRI AUG 29 2014

ACTIVE/PROGRESSIVE NORTHERN STREAM FLOW WILL CONTINUE THROUGH THE
PERIOD WITH A STRONG UPPER LEVEL TROUGH ON TRACK TO ADVECT THROUGH
THE REGION SUN...WITH A WEAKER SHORTWAVE IMPULSE LIKELY MONDAY.
TROUGH RELOADING OVER THE NE PAC TUE-WED FAVORED IN ECMWF/GFS/GEM
SOLUTIONS TUE...WHICH WILL SUPPORT SHORTWAVE RIDGING OVER THE
NORTHERN PLAINS WITH DRY AND WARMER CONDITIONS TUE-WED. NO SIG
CHANGES FROM THE PREVIOUS FORECAST GIVEN VERY GOOD DETERMINISTIC
MODEL CONSISTENCY AND CONTINUITY THROUGH THE PERIOD...WHICH IS IN
LINE WITH GEFS/NAEFS MEANS.

UPPER LEVEL TROUGH WILL BE IN THE PROCESS OF SHIFTING EAST ACROSS
THE NORTHERN PLAINS SUNDAY. ASSOCIATED MID LEVEL COLD POOL WILL
SUPPORT STEEP LL LAPSE RATES OVER THE FA WITH RESIDUAL LL MOISTURE
IN PLACE. DIURNAL HEATING COUPLED WITH BH/NE WY TERRAIN INFLUENCES
SHOULD SUPPORT SCT TO ISOLD SHRA/TS ESP SOUTH HALF OF THE FA.
REMAINED CLOSE TO PREVIOUS POP NUMBERS WITH MID RANGE CHANCE
COVERING PRECIP CONCERNS. OTHERWISE...A WEAKER WESTERLY FLOW IMPULSE
STILL INDICATED IN FORECAST MODELS MONDAY...POSSIBLY SUPPORTING A
FEW SHRA/TS...ALTHOUGH DRY PROFILES WILL LIMIT QPF AND
COVERAGE...ESP AWAY FROM THE BH. DRY CONDS EXPECTED TUE-WED WITH
MEAN DEEP LAYER RIDGING. THE NEXT NE PAC UPPER LEVEL TROUGH WILL
EJECT EAST INTO THE NORTHERN PLAINS WED NIGHT INTO
THUR...INTERACTING WITH A LEE SIDE TROUGH. INCREASING LSA WED NIGHT
THROUGH THUR WILL SUPPORT INCREASING CHANCES FOR SHRA/TS...FAR NW
SAT NIGHT WITH POPS TRENDING SOUTH THROUGH THUR AS THE UPPER TROUGH
SHIFTS EAST WITH THE REFLECTED SFC WAVE. DID BUMP POPS UP TO LOW
CHANCE NW 2/3 THUR NIGHT.

COOL/BELOW NORMAL TEMPS /5-10 DEGREES/ EXPECTED SUNDAY THROUGH
MONDAY...ESP NW AREAS. WARMING CONDITIONS CAN BE EXPECTED TUE-THUR
MOST AREAS. HOWEVER...NW AREAS MAY SEE THE START OF A COOLING TREND
THUR AS THE NEXT COLD FRONT SHIFTS SE INTO THE REGION.

&&

.AVIATION...FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT
ISSUED AT 251 AM MDT FRI AUG 29 2014

MVFR CONDITIONS IN PATCHY FOG MAY DEVELOP OVER PARTS OF WESTERN
SOUTH DAKOTA LATE TONIGHT/EARLY FRIDAY MORNING. A BAND OF ISOLATED
TO SCATTERED SHOWERS AND THUNDERSTORMS WILL MOVE INTO NORTHEASTERN
WYOMING LATE TONIGHT AND WILL SPREAD EASTWARD INTO WESTERN SOUTH
DAKOTA ON FRIDAY MORNING. THUNDERSTORMS WILL INCREASE IN COVERAGE
OVER WESTERN AND CENTRAL SOUTH DAKOTA ON FRIDAY AFTERNOON.

&&

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

$$

SHORT TERM...13
LONG TERM...JC
AVIATION...JC








000
FXUS63 KUNR 290852
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
252 AM MDT FRI AUG 29 2014

.SHORT TERM...TODAY THROUGH SATURDAY NIGHT
ISSUED AT 251 AM MDT FRI AUG 29 2014

STRONG SHORTWAVE TROUGH IS CROSSING THE CENTRAL PLAINS INTO THE ERN
DAKOTAS TO UPPER MIDWEST. ZONAL FLOW SITS ACROSS THE WRN CONUS WITH
A MUCH WEAK SHORTWAVE CROSS CNTRL/ERN MT. SURROUNDING RADAR SITES
SHOWING -SHRA/TSRA CROSSING ERN MT TO NRN WY. A SURFACE COLD FRONT
ALSO ASSOCIATED WITH THE WAVE/PRECIP IS SLIDING SE AND IS VISIBLE ON
THE BIS/BYZ RADARS.

COLD FRONT/UPPER WAVE WILL QUICKLY PUSH THROUGH THE CWA TODAY
BRINGING CHANCES FOR -SHRA/TSRA. LATEST TIMING APPEARS TO HAVE THE
AREA OF PRECIP OVER THE BLKHLS AREA BY LATE MORNING...THE CONTINUING
EWD INTO THE WRN SD PLAINS THROUGH THE AFTERNOON. STRONG INSTABILITY
DEVELOPING AHEAD OF THE FRONT OVER WRN/CNTRL SD PLAINS COULD RESULT
IN SOME STRONG STORMS THIS AFTERNOON...BUT SHEAR WILL BE QUITE WEAK
SO STORM BEHAVIOR IS EXPECTED TO BE MORE PULSE LIKE. TEMPS WILL
RANGE FROM THE MID 70S TO MID 80S...WITH COOLER TEMPS OVER NW SD/NE
WY WHERE THE FROPA OCCURS EARLIER THIS MORNING. WINDS IMMEDIATELY
BEHIND THE FRONTAL BOUNDARY WILL BECOME BREEZY...WITH GUSTS TO
AROUND 30KT...BUT WILL BE LIMITED TO AN HOUR OR TWO AFTER THE FRONT
PASSES.

WEAK RIDGING BUILDS BEHIND THE DEPARTING WAVE TONIGHT CLEARING OUT
PRECIP LATE TNGT TO SATURDAY MRNG. THE NEXT LONGWAVE TROUGH WILL
CROSS THE PACIFIC NW TO NRN ROCKIES SATURDAY...WITH ACTIVE SW FLOW
DEVELOPING. CHANCES FOR SHRA/TSRA WILL AGAIN RETURN SAT AFTN/EVNG.
GOOD INSTABILITY AND STRONG LL SHEAR OVER NW SD WILL RESULT IN
STRONG TO SEVERE TSRA SAT AFTN/EVNG. LARGE HAIL AND DAMAGING WINDS
ARE THE MAIN THREATS.

&&

.LONG TERM...SUNDAY THROUGH THURSDAY
ISSUED AT 251 AM MDT FRI AUG 29 2014

ACTIVE/PROGRESSIVE NORTHERN STREAM FLOW WILL CONTINUE THROUGH THE
PERIOD WITH A STRONG UPPER LEVEL TROUGH ON TRACK TO ADVECT THROUGH
THE REGION SUN...WITH A WEAKER SHORTWAVE IMPULSE LIKELY MONDAY.
TROUGH RELOADING OVER THE NE PAC TUE-WED FAVORED IN ECMWF/GFS/GEM
SOLUTIONS TUE...WHICH WILL SUPPORT SHORTWAVE RIDGING OVER THE
NORTHERN PLAINS WITH DRY AND WARMER CONDITIONS TUE-WED. NO SIG
CHANGES FROM THE PREVIOUS FORECAST GIVEN VERY GOOD DETERMINISTIC
MODEL CONSISTENCY AND CONTINUITY THROUGH THE PERIOD...WHICH IS IN
LINE WITH GEFS/NAEFS MEANS.

UPPER LEVEL TROUGH WILL BE IN THE PROCESS OF SHIFTING EAST ACROSS
THE NORTHERN PLAINS SUNDAY. ASSOCIATED MID LEVEL COLD POOL WILL
SUPPORT STEEP LL LAPSE RATES OVER THE FA WITH RESIDUAL LL MOISTURE
IN PLACE. DIURNAL HEATING COUPLED WITH BH/NE WY TERRAIN INFLUENCES
SHOULD SUPPORT SCT TO ISOLD SHRA/TS ESP SOUTH HALF OF THE FA.
REMAINED CLOSE TO PREVIOUS POP NUMBERS WITH MID RANGE CHANCE
COVERING PRECIP CONCERNS. OTHERWISE...A WEAKER WESTERLY FLOW IMPULSE
STILL INDICATED IN FORECAST MODELS MONDAY...POSSIBLY SUPPORTING A
FEW SHRA/TS...ALTHOUGH DRY PROFILES WILL LIMIT QPF AND
COVERAGE...ESP AWAY FROM THE BH. DRY CONDS EXPECTED TUE-WED WITH
MEAN DEEP LAYER RIDGING. THE NEXT NE PAC UPPER LEVEL TROUGH WILL
EJECT EAST INTO THE NORTHERN PLAINS WED NIGHT INTO
THUR...INTERACTING WITH A LEE SIDE TROUGH. INCREASING LSA WED NIGHT
THROUGH THUR WILL SUPPORT INCREASING CHANCES FOR SHRA/TS...FAR NW
SAT NIGHT WITH POPS TRENDING SOUTH THROUGH THUR AS THE UPPER TROUGH
SHIFTS EAST WITH THE REFLECTED SFC WAVE. DID BUMP POPS UP TO LOW
CHANCE NW 2/3 THUR NIGHT.

COOL/BELOW NORMAL TEMPS /5-10 DEGREES/ EXPECTED SUNDAY THROUGH
MONDAY...ESP NW AREAS. WARMING CONDITIONS CAN BE EXPECTED TUE-THUR
MOST AREAS. HOWEVER...NW AREAS MAY SEE THE START OF A COOLING TREND
THUR AS THE NEXT COLD FRONT SHIFTS SE INTO THE REGION.

&&

.AVIATION...FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT
ISSUED AT 251 AM MDT FRI AUG 29 2014

MVFR CONDITIONS IN PATCHY FOG MAY DEVELOP OVER PARTS OF WESTERN
SOUTH DAKOTA LATE TONIGHT/EARLY FRIDAY MORNING. A BAND OF ISOLATED
TO SCATTERED SHOWERS AND THUNDERSTORMS WILL MOVE INTO NORTHEASTERN
WYOMING LATE TONIGHT AND WILL SPREAD EASTWARD INTO WESTERN SOUTH
DAKOTA ON FRIDAY MORNING. THUNDERSTORMS WILL INCREASE IN COVERAGE
OVER WESTERN AND CENTRAL SOUTH DAKOTA ON FRIDAY AFTERNOON.

&&

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

$$

SHORT TERM...13
LONG TERM...JC
AVIATION...JC








000
FXUS65 KRIW 290547
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
209 PM MDT THU AUG 28 2014

.SHORT TERM...TONIGHT AND FRIDAY (ISSUED AT 209 PM MDT THU)

FLOW IS A LITTLE MORE COMPLEX THAN THE MODELS ARE INDICATING TODAY
WITH COMBINATION OF SHORTWAVE APPROACHING FROM THE PACNW...UPPER
CIRCULATION SEEN IN WATER VAPOR ENTERING NWRN CA AND PACIFIC
MOISTURE JUST UPSTREAM OF THAT WAVE WHICH APPEARS TO BE REMNANT
MOISTURE FROM OLD HURRICANE LOWELL. A LITTLE BIT OF ALL OF THESE
WILL COME INTO PLAY OVER THE NEXT 24 TO 30 HOURS. THE FIRST TWO MAY
MOVE ACROSS ABOUT THE SAME TIME LATER TONIGHT INTO FRIDAY MORNING
WITH A SWATH OF SHOWERS FOR THE NORTH 1/3 TO 1/2. A FEW EVENING
SHOWERS OR THUNDERSTORMS MAY ALSO DEVELOP IN THE NW WHERE LIMITED
MOISTURE/INSTABILITY IS EXPECTED. THEN DURING THE DAY FRIDAY...THE
FRONTAL BOUNDARY LAID DOWN FROM OUR OVERNIGHT SYSTEM WILL DROP INTO
OUR NRN AND ERN ZONES AND MAY BE A FOCUS FOR A FEW STORMS FRIDAY
AFTERNOON. THE MOISTURE ASSOCIATED FROM OLD HURRICANE LOWELL MOVES
INTO THE WEST DURING THE DAY AND THEN SPREADS EAST INTO THE
AFTERNOON. FORECAST SOUNDINGS SHOW THE BEST INSTABILITY ALONG AND
BEHIND THE FRONT UP NORTH WITH CAPES OF 300-600 J/KG AND SOME MODEST
SHEAR. FURTHER SOUTH...IT`S DRIER BUT WITH DECENT HEATING WE SHOULD
SEE A FEW HUNDRED JOULES OF ENERGY AND THUS ISOLATED SHOWERS AND
THUNDERSTORMS. INCREASED OUR ISOLATED COVERAGE TO INCLUDE OUR
CENTRAL AND NRN SECTIONS.

.LONG TERM...FRIDAY NIGHT THROUGH THURSDAY

OVERALL...LR MDLS IN GOOD AGREEMENT THROUGHOUT THE FORECAST PERIOD
WITH ONLY MODEST DIVERGENCE FOUND FROM TUE NIGHT THRU THURSDAY AS
MDLS HAVE MAINLY TEMPORAL DIFFERENCES IN HANDLING THE NEXT MAJOR UPR
LVL TROF. AFTER THAT...THE MDLS START TO CONVERGE...GO FIGURE.

FRI NIGHT...QUICK HIT RIDGING IN PROGRESS AHEAD OF APPROACHING NW
COASTAL CONUS TROF WITH NOT MUCH IN THE WAY OF WX GOING ON AT THE
BEGINNING OF THE PERIOD EXCEPT FOR A FEW DIURNALLY FORCED MOUNTAIN
STORMS IN THE EVENING. HOWEVER...BY THE END OF THE FIRST
PERIOD...THE EWD TRANSLATION OF THE TROF WILL PUT INCREASED UPR
DIFLUENT FLOW ALONG WITH A MODEST INCREASE MOISTURE ACROSS THE NW/W
FA. AT THE SFC...DEVELOPING LOW PRESSURE AND A FRONT WILL ALSO
PROCEED UNDER THE INFLUENCE OF THE UPR TROF. THIS WILL ALL BRING
INCREASING CHANCES FOR SHRA OVR THE NW/W FA TO START THE DAY. AS SAT
WEARS ON...THE NOW PROGRESSIVE NATURE OF THE UPR LVLS WILL SPREAD
MUCH STRONGER UPR FLOW OVERHEAD RESULTING IN INCREASED NET UPWARD
LIFT. THIS TOGETHER WILL THE GREATLY IMPROVE CONVECTIVE CHANCES
ALONG WITH GROWTH POTENTIAL BY MID-DAY...WITH A FEW STRONG STORMS
EXPECTED. STRONGER CONVECTION...WITH (MOSTLY SMALL) HAIL
EARLY...EXPECTED ACROSS THE NRN FA...ESPECIALLY PARK COUNTY...BEFORE
TRANSITIONING TO MORE OF A STRONG WIND GUST/BRIEF HEAVY RAIN
SITUATION THROUGH THE REST OF THE DAY. SHEAR WILL COME IN THE FORM
OF SPEED SHEAR W/ HEIGHT THIS DAY...AS INCREASING UNIDIRECTIONAL SW
FLOW OVERRUNS THE CWA...LENDING ITSELF TO AMBIENT GUSTY WEST TO
SOUTHWEST WINDS TO BEGIN WITH. PUTTING CONVECTION INTO  THIS
ATMOSPHERE WILL ONLY INCREASE THE LIKELIHOOD FOR A FEW STRONG TO
MARGINALLY SVR GUSTS BY AFTERNOON AS STORM RACE TO THE NE AT 30 PLUS
MPH. SIGNIFICANT RAINFALL DOES NOT LOOK TO BE A PROBLEM.

SUNDAY...AS THE TROF CONTINUES CROSSING THE STATE FROM W TO E...
MUCH COOLER CONDITIONS FOR SURE...WITH CONTINUED GUSTY W TO WSW
WINDS ACROSS THE AREA WEST OF THE DIVIDE BEHIND THE EXITING SFC
FRONT. PRECIP CHCS WILL ALSO BE ENDING FROM CNTRL WY TO THE
ERN BORDER THROUGH THE DAY.

MONDAY THRU THURSDAY...ISOLATED TO WIDELY SCATTERED SHRA/ISO TSRA
MONDAY AFTERNOON ACROSS THE NRN/NERN FA AS THE STATE ENTERS NW UPR
FLOW AND STAYS UNDER A WEAKENING INFLUENCE FROM THE BROADENING TROF
AS IT EXPENDS EWD ACROSS THE CONUS. THE FA THEN ENTERS A MODEST
WARMING AND DRYING PERIOD WITH TEMPS RETURNING TO LOW END SEASONAL BY
MID WEEK...WITH ONLY EVER SO SLIGHT CHCS FOR DIURNAL MOUNTAINS ISO
SHRA/TSRA LATER WEDNESDAY...INCREASING TO PERHAPS WIDELY SCATTERED
CHCS THU AFTERNOON AS THE NEXT IN A CONSTANT PROGRESSION UPR LVL
TROFS BEGINS TO DIG INTO THE WRN CONUS AND INFLUENCE WX W OF THE
DIVIDE IN WY ONCE AGAIN.

&&

.AVIATION.../06Z ISSUANCE/

AN UPPER LEVEL DISTURBANCE WILL CONTINUE TO PUSH EAST ACROSS MONTANA
OVERNIGHT.  SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS ARE
EXPECTED TO BE MOSTLY EAST OF THE INTERSTATE 25 CORRIDOR BY 12Z
FRIDAY...POSSIBLY EXTENDING SSW INTO VCNTY KCPR THROUGH AROUND 14Z.

A COUPLE OF MORE RIPPLES IN THE FLOW WILL PUSH EAST ACROSS THE
NORTHERN GREAT BASIN...ACROSS WYOMING FRIDAY AFTERNOON AND EVENING.
MAINLY ISOLATED -TSRA/-SHRA WILL OCCUR ACROSS MOST OF THE AREA WITH
POSSIBLY MORE SCT ACTIVITY OVER THE HIGH TERRAIN.  THIS ACTIVITY
WILL MOSTLY DISSIPATE SHORTLY AFTER SUNSET.  THE NEXT PACIFIC SYSTEM
WILL SPREAD MID AND HIGH CLOUDS VCNTY AND WEST OF THE DIVIDE 06Z-12Z
SATURDAY ALONG WITH ISOLD -SHRA.

&&

.FIRE WEATHER...
A FEW SHOWERS AND ISOLATED EVENING THUNDERSTORMS WILL BE POSSIBLE
ACROSS THE EXTREME NORTHWEST DURING THE EVENING...SPREADING EAST AND
A LITTLE SOUTH OVERNIGHT...WITH DRY CONDITIONS OTHERWISE. ANOTHER SYSTEM
WILL MOVE IN FROM THE WEST DURING THE DAY FRIDAY WHICH WILL RESULT IN
ISOLATED THUNDERSTORMS ACROSS THE CENTRAL AND NORTHERN PART OF THE
DISTRICT. THE MAIN THREAT FROM THESE WILL BE GUSTY WIND TO 45 MPH AND
LIGHTNING. ON SATURDAY...A STRONGER COLD FRONT WILL SWEEP EAST
ACROSS THE AREA WITH INCREASING SOUTHWEST WINDS AHEAD OF IT AND ISOLATED
TO WIDELY SCATTERED THUNDERSTORMS ALONG AND BEHIND THE COLD FRONT.
FIRE WEATHER CONCERNS WILL INCREASE AHEAD OF THE FRONT FOR A FEW
HOURS AS MIN RH`S DROP INTO THE TEENS AND SW WINDS BLOW 20 TO 35 MPH.
HOWEVER...ALL THE RECENT RAIN WILL LOWER THE THREAT AND PROBABLY ALLOW
THE MIN RH`S TO STAY ABOVE CRITICAL LEVELS. WE WILL CONTINUE TO
MONITOR.

&&

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

&&

$$

SHORT TERM...SKRBAC
LONG TERM...BRAUN
AVIATION...AEM
FIRE WEATHER...SKRBAC












000
FXUS65 KRIW 290547
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
209 PM MDT THU AUG 28 2014

.SHORT TERM...TONIGHT AND FRIDAY (ISSUED AT 209 PM MDT THU)

FLOW IS A LITTLE MORE COMPLEX THAN THE MODELS ARE INDICATING TODAY
WITH COMBINATION OF SHORTWAVE APPROACHING FROM THE PACNW...UPPER
CIRCULATION SEEN IN WATER VAPOR ENTERING NWRN CA AND PACIFIC
MOISTURE JUST UPSTREAM OF THAT WAVE WHICH APPEARS TO BE REMNANT
MOISTURE FROM OLD HURRICANE LOWELL. A LITTLE BIT OF ALL OF THESE
WILL COME INTO PLAY OVER THE NEXT 24 TO 30 HOURS. THE FIRST TWO MAY
MOVE ACROSS ABOUT THE SAME TIME LATER TONIGHT INTO FRIDAY MORNING
WITH A SWATH OF SHOWERS FOR THE NORTH 1/3 TO 1/2. A FEW EVENING
SHOWERS OR THUNDERSTORMS MAY ALSO DEVELOP IN THE NW WHERE LIMITED
MOISTURE/INSTABILITY IS EXPECTED. THEN DURING THE DAY FRIDAY...THE
FRONTAL BOUNDARY LAID DOWN FROM OUR OVERNIGHT SYSTEM WILL DROP INTO
OUR NRN AND ERN ZONES AND MAY BE A FOCUS FOR A FEW STORMS FRIDAY
AFTERNOON. THE MOISTURE ASSOCIATED FROM OLD HURRICANE LOWELL MOVES
INTO THE WEST DURING THE DAY AND THEN SPREADS EAST INTO THE
AFTERNOON. FORECAST SOUNDINGS SHOW THE BEST INSTABILITY ALONG AND
BEHIND THE FRONT UP NORTH WITH CAPES OF 300-600 J/KG AND SOME MODEST
SHEAR. FURTHER SOUTH...IT`S DRIER BUT WITH DECENT HEATING WE SHOULD
SEE A FEW HUNDRED JOULES OF ENERGY AND THUS ISOLATED SHOWERS AND
THUNDERSTORMS. INCREASED OUR ISOLATED COVERAGE TO INCLUDE OUR
CENTRAL AND NRN SECTIONS.

.LONG TERM...FRIDAY NIGHT THROUGH THURSDAY

OVERALL...LR MDLS IN GOOD AGREEMENT THROUGHOUT THE FORECAST PERIOD
WITH ONLY MODEST DIVERGENCE FOUND FROM TUE NIGHT THRU THURSDAY AS
MDLS HAVE MAINLY TEMPORAL DIFFERENCES IN HANDLING THE NEXT MAJOR UPR
LVL TROF. AFTER THAT...THE MDLS START TO CONVERGE...GO FIGURE.

FRI NIGHT...QUICK HIT RIDGING IN PROGRESS AHEAD OF APPROACHING NW
COASTAL CONUS TROF WITH NOT MUCH IN THE WAY OF WX GOING ON AT THE
BEGINNING OF THE PERIOD EXCEPT FOR A FEW DIURNALLY FORCED MOUNTAIN
STORMS IN THE EVENING. HOWEVER...BY THE END OF THE FIRST
PERIOD...THE EWD TRANSLATION OF THE TROF WILL PUT INCREASED UPR
DIFLUENT FLOW ALONG WITH A MODEST INCREASE MOISTURE ACROSS THE NW/W
FA. AT THE SFC...DEVELOPING LOW PRESSURE AND A FRONT WILL ALSO
PROCEED UNDER THE INFLUENCE OF THE UPR TROF. THIS WILL ALL BRING
INCREASING CHANCES FOR SHRA OVR THE NW/W FA TO START THE DAY. AS SAT
WEARS ON...THE NOW PROGRESSIVE NATURE OF THE UPR LVLS WILL SPREAD
MUCH STRONGER UPR FLOW OVERHEAD RESULTING IN INCREASED NET UPWARD
LIFT. THIS TOGETHER WILL THE GREATLY IMPROVE CONVECTIVE CHANCES
ALONG WITH GROWTH POTENTIAL BY MID-DAY...WITH A FEW STRONG STORMS
EXPECTED. STRONGER CONVECTION...WITH (MOSTLY SMALL) HAIL
EARLY...EXPECTED ACROSS THE NRN FA...ESPECIALLY PARK COUNTY...BEFORE
TRANSITIONING TO MORE OF A STRONG WIND GUST/BRIEF HEAVY RAIN
SITUATION THROUGH THE REST OF THE DAY. SHEAR WILL COME IN THE FORM
OF SPEED SHEAR W/ HEIGHT THIS DAY...AS INCREASING UNIDIRECTIONAL SW
FLOW OVERRUNS THE CWA...LENDING ITSELF TO AMBIENT GUSTY WEST TO
SOUTHWEST WINDS TO BEGIN WITH. PUTTING CONVECTION INTO  THIS
ATMOSPHERE WILL ONLY INCREASE THE LIKELIHOOD FOR A FEW STRONG TO
MARGINALLY SVR GUSTS BY AFTERNOON AS STORM RACE TO THE NE AT 30 PLUS
MPH. SIGNIFICANT RAINFALL DOES NOT LOOK TO BE A PROBLEM.

SUNDAY...AS THE TROF CONTINUES CROSSING THE STATE FROM W TO E...
MUCH COOLER CONDITIONS FOR SURE...WITH CONTINUED GUSTY W TO WSW
WINDS ACROSS THE AREA WEST OF THE DIVIDE BEHIND THE EXITING SFC
FRONT. PRECIP CHCS WILL ALSO BE ENDING FROM CNTRL WY TO THE
ERN BORDER THROUGH THE DAY.

MONDAY THRU THURSDAY...ISOLATED TO WIDELY SCATTERED SHRA/ISO TSRA
MONDAY AFTERNOON ACROSS THE NRN/NERN FA AS THE STATE ENTERS NW UPR
FLOW AND STAYS UNDER A WEAKENING INFLUENCE FROM THE BROADENING TROF
AS IT EXPENDS EWD ACROSS THE CONUS. THE FA THEN ENTERS A MODEST
WARMING AND DRYING PERIOD WITH TEMPS RETURNING TO LOW END SEASONAL BY
MID WEEK...WITH ONLY EVER SO SLIGHT CHCS FOR DIURNAL MOUNTAINS ISO
SHRA/TSRA LATER WEDNESDAY...INCREASING TO PERHAPS WIDELY SCATTERED
CHCS THU AFTERNOON AS THE NEXT IN A CONSTANT PROGRESSION UPR LVL
TROFS BEGINS TO DIG INTO THE WRN CONUS AND INFLUENCE WX W OF THE
DIVIDE IN WY ONCE AGAIN.

&&

.AVIATION.../06Z ISSUANCE/

AN UPPER LEVEL DISTURBANCE WILL CONTINUE TO PUSH EAST ACROSS MONTANA
OVERNIGHT.  SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS ARE
EXPECTED TO BE MOSTLY EAST OF THE INTERSTATE 25 CORRIDOR BY 12Z
FRIDAY...POSSIBLY EXTENDING SSW INTO VCNTY KCPR THROUGH AROUND 14Z.

A COUPLE OF MORE RIPPLES IN THE FLOW WILL PUSH EAST ACROSS THE
NORTHERN GREAT BASIN...ACROSS WYOMING FRIDAY AFTERNOON AND EVENING.
MAINLY ISOLATED -TSRA/-SHRA WILL OCCUR ACROSS MOST OF THE AREA WITH
POSSIBLY MORE SCT ACTIVITY OVER THE HIGH TERRAIN.  THIS ACTIVITY
WILL MOSTLY DISSIPATE SHORTLY AFTER SUNSET.  THE NEXT PACIFIC SYSTEM
WILL SPREAD MID AND HIGH CLOUDS VCNTY AND WEST OF THE DIVIDE 06Z-12Z
SATURDAY ALONG WITH ISOLD -SHRA.

&&

.FIRE WEATHER...
A FEW SHOWERS AND ISOLATED EVENING THUNDERSTORMS WILL BE POSSIBLE
ACROSS THE EXTREME NORTHWEST DURING THE EVENING...SPREADING EAST AND
A LITTLE SOUTH OVERNIGHT...WITH DRY CONDITIONS OTHERWISE. ANOTHER SYSTEM
WILL MOVE IN FROM THE WEST DURING THE DAY FRIDAY WHICH WILL RESULT IN
ISOLATED THUNDERSTORMS ACROSS THE CENTRAL AND NORTHERN PART OF THE
DISTRICT. THE MAIN THREAT FROM THESE WILL BE GUSTY WIND TO 45 MPH AND
LIGHTNING. ON SATURDAY...A STRONGER COLD FRONT WILL SWEEP EAST
ACROSS THE AREA WITH INCREASING SOUTHWEST WINDS AHEAD OF IT AND ISOLATED
TO WIDELY SCATTERED THUNDERSTORMS ALONG AND BEHIND THE COLD FRONT.
FIRE WEATHER CONCERNS WILL INCREASE AHEAD OF THE FRONT FOR A FEW
HOURS AS MIN RH`S DROP INTO THE TEENS AND SW WINDS BLOW 20 TO 35 MPH.
HOWEVER...ALL THE RECENT RAIN WILL LOWER THE THREAT AND PROBABLY ALLOW
THE MIN RH`S TO STAY ABOVE CRITICAL LEVELS. WE WILL CONTINUE TO
MONITOR.

&&

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

&&

$$

SHORT TERM...SKRBAC
LONG TERM...BRAUN
AVIATION...AEM
FIRE WEATHER...SKRBAC













000
FXUS63 KUNR 290511
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
1111 PM MDT THU AUG 28 2014

.SHORT TERM...THIS EVENING THROUGH FRIDAY NIGHT
ISSUED AT 330 PM MDT THU AUG 28 2014

CURRENT SURFACE ANALYSIS SHOWS LOW PRESSURE OVER CENTRAL
NEB...WITH INVERTED TROF STRETCHING NORTHWARD ACROSS CENTRAL SD.
HIGH PRESSURE IS IN PLACE OVER THE CENTRAL ROCKIES. UPPER LEVEL
ANALYSIS SHOWS LOW NOW OVER FAR NORTHEAST CO...SLOWLY MOVING EAST-
SOUTHEAST. KUDX RADAR SHOWS ISOLATED TO SCATTERED SHOWERS FROM
CENTRAL SD TO FAR SOUTHWEST SD. THERE ARE A FEW LIGHTNING STRIKES
FROM TIME TO TIME WITH THE ACTIVITY OVER SOUTHERN SD. SKIES RANGE
FROM MOSTLY SUNNY OVER NORTHEAST WY AND FAR NORTHWEST SD TO MOSTLY
CLOUDY SOUTH AND EAST OF THE BLACK HILLS. TEMPS ARE IN THE 70S AND
LOWER 80S WITH LIGHT NORTHERLY WINDS IN MOST AREAS.

CONDITIONS WILL CONTINUE TO GRADUALLY IMPROVE THROUGH THE EVENING
FOR AREAS SOUTH AND EAST OF THE BLACK HILLS...WITH MOSTLY CLEAR
SKIES OVER WESTERN AND NORTHERN AREAS. HAVE ADDED CHANCES FOR
SHOWERS AND STORMS ACROSS SOUTH CENTRAL SD FOR THE EVENING HOURS AS
SYSTEM IS SLOWER TO MOVE OUT THAN WAS EXPECTED. WITH LOW LEVEL
MOISTURE HANGING AROUND OVER EASTERN PORTIONS OF THE CWA...HAVE KEPT
PATCHY FOG IN FOR MOST OF THE SD PLAINS. LOWS TONIGHT WILL BE IN THE
50S AND LOWER 60S. WINDS WILL MOSTLY BE LIGHT AND VARIABLE.

THE NEXT UPPER LEVEL WAVE...MUCH WEAKER THAN THE CURRENT ONE...WILL
MOVE QUICKLY INTO THE AREA ON FRIDAY...WITH INCREASING CHANCES FOR
SHOWERS AND THUNDERSTORMS THROUGH THE DAY FROM WEST TO EAST. A WEAK
COLD FRONT WILL ALSO SLIDE SOUTH INTO THE AREA WITH THE SHORTWAVE.
THE THREAT FOR SEVERE STORMS WILL REMAIN VERY LOW...BUT SUFFICIENT
INSTABILITY IS EXPECTED TO THE EAST OF THE BLACK HILLS IN THE
AFTERNOON TO POSSIBLY GET A STRONG STORM OR TWO GOING. HIGHS WILL BE
IN THE 80S...WITH SOME 70S ACROSS THE BLACK HILLS AND FAR
NORTHWESTERN SD. NORTHWESTERLY WINDS WILL INCREASE BEHIND THE FRONT
DURING THE LATE MORNING AND AFTERNOON...A BIT BREEZY AT TIMES OVER
THE WESTERN SD PLAINS. LINGERING SHOWERS SHOULD TAPER OFF QUICKLY IN
THE EVENING AS THE WAVE PUSHES EAST OF THE AREA.

&&

.LONG TERM...SATURDAY THROUGH THURSDAY
ISSUED AT 330 PM MDT THU AUG 28 2014

SATURDAY...SHORTWAVE RIDGE OVER THE CWA WILL QUICKLY MOVE INTO THE
MIDWEST DURING THE DAY AS A SHORTWAVE TROUGH ZIPS THROUGH MT INTO
ND/WY BY SATURDAY EVENING. SURFACE CYCLONE WILL DEVELOP OVER EASTERN
MT AND MOVES INTO THE CENTRAL DAKOTAS SATURDAY NIGHT. LOW LEVEL
MOISTURE CONVERGENCE ALONG THE FRONT WILL RESULT IN A NARROW BAND OF
1-2KJ/KG MLCAPE FROM SOUTHEAST MT INTO CENTRAL SD. 15-20M/S 0-6KM
BULK SHEAR SPREADS ACROSS NORTHWEST SD DURING PEAK HEATING. MLCIN
SHOULD BE BROKEN BY SURFACE FORCING AND LIFT AHEAD OF SHORTWAVE
RESULTING IN STRONG/POTENTIALLY SEVERE THUNDERSTORMS LATER SATURDAY
AFTERNOON INTO THE EVENING HOURS. STORMS MAY CONGEAL INTO A SMALL
MCS GIVEN DEVELOPING 50KT LOW LEVEL JET ACROSS THE EASTERN DAKOTAS
SATURDAY NIGHT. TEMPERATURES WILL BE TRICKY WITH VERY WARM READINGS
AHEAD OF THE LOW AND COOLER READINGS BEHIND THE FRONT.

SUNDAY THROUGH TUESDAY...UPPER TROUGH WITH EMBEDDED SHORTWAVES
SAUNTERS ACROSS THE DAKOTAS/SOUTH CENTRAL CANADA BRINGING SHRA/TSRA
CHANCES...ALTHOUGH COVERAGE SHOULD BE LOWER THAN RECENT MEMORY GIVEN
DRIER NORTHWEST FLOW. TEMPERATURES WILL BE NOTICEABLY COOLER SUNDAY
AND THEN WARM SLIGHTLY THROUGH TUESDAY.

WEDNESDAY/THURSDAY...UPPER RIDGE SHOULD BUILD INTO THE NORTHERN
PLAINS AS UPPER TROUGH DEEPENS OVER THE NORTHWEST US. DRIER AND
WARMER PATTERN MAY EVOLVE GIVEN THERMAL RIDGE AMPLIFICATION.

&&

.AVIATION...FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT
ISSUED AT 1108 PM MDT THU AUG 28 2014

MVFR CONDITIONS IN PATCHY FOG MAY DEVELOP OVER PARTS OF WESTERN
SOUTH DAKOTA LATE TONIGHT/EARLY FRIDAY MORNING. A BAND OF ISOLATED
TO SCATTERED SHOWERS AND THUNDERSTORMS WILL MOVE INTO NORTHEASTERN
WYOMING LATE TONIGHT AND WILL SPREAD EASTWARD INTO WESTERN SOUTH
DAKOTA ON FRIDAY MORNING. THUNDERSTORMS WILL INCREASE IN COVERAGE
OVER WESTERN AND CENTRAL SOUTH DAKOTA ON FRIDAY AFTERNOON.

&&

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

$$

SHORT TERM...26
LONG TERM...HELGESON
AVIATION...10






000
FXUS63 KUNR 290511
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
1111 PM MDT THU AUG 28 2014

.SHORT TERM...THIS EVENING THROUGH FRIDAY NIGHT
ISSUED AT 330 PM MDT THU AUG 28 2014

CURRENT SURFACE ANALYSIS SHOWS LOW PRESSURE OVER CENTRAL
NEB...WITH INVERTED TROF STRETCHING NORTHWARD ACROSS CENTRAL SD.
HIGH PRESSURE IS IN PLACE OVER THE CENTRAL ROCKIES. UPPER LEVEL
ANALYSIS SHOWS LOW NOW OVER FAR NORTHEAST CO...SLOWLY MOVING EAST-
SOUTHEAST. KUDX RADAR SHOWS ISOLATED TO SCATTERED SHOWERS FROM
CENTRAL SD TO FAR SOUTHWEST SD. THERE ARE A FEW LIGHTNING STRIKES
FROM TIME TO TIME WITH THE ACTIVITY OVER SOUTHERN SD. SKIES RANGE
FROM MOSTLY SUNNY OVER NORTHEAST WY AND FAR NORTHWEST SD TO MOSTLY
CLOUDY SOUTH AND EAST OF THE BLACK HILLS. TEMPS ARE IN THE 70S AND
LOWER 80S WITH LIGHT NORTHERLY WINDS IN MOST AREAS.

CONDITIONS WILL CONTINUE TO GRADUALLY IMPROVE THROUGH THE EVENING
FOR AREAS SOUTH AND EAST OF THE BLACK HILLS...WITH MOSTLY CLEAR
SKIES OVER WESTERN AND NORTHERN AREAS. HAVE ADDED CHANCES FOR
SHOWERS AND STORMS ACROSS SOUTH CENTRAL SD FOR THE EVENING HOURS AS
SYSTEM IS SLOWER TO MOVE OUT THAN WAS EXPECTED. WITH LOW LEVEL
MOISTURE HANGING AROUND OVER EASTERN PORTIONS OF THE CWA...HAVE KEPT
PATCHY FOG IN FOR MOST OF THE SD PLAINS. LOWS TONIGHT WILL BE IN THE
50S AND LOWER 60S. WINDS WILL MOSTLY BE LIGHT AND VARIABLE.

THE NEXT UPPER LEVEL WAVE...MUCH WEAKER THAN THE CURRENT ONE...WILL
MOVE QUICKLY INTO THE AREA ON FRIDAY...WITH INCREASING CHANCES FOR
SHOWERS AND THUNDERSTORMS THROUGH THE DAY FROM WEST TO EAST. A WEAK
COLD FRONT WILL ALSO SLIDE SOUTH INTO THE AREA WITH THE SHORTWAVE.
THE THREAT FOR SEVERE STORMS WILL REMAIN VERY LOW...BUT SUFFICIENT
INSTABILITY IS EXPECTED TO THE EAST OF THE BLACK HILLS IN THE
AFTERNOON TO POSSIBLY GET A STRONG STORM OR TWO GOING. HIGHS WILL BE
IN THE 80S...WITH SOME 70S ACROSS THE BLACK HILLS AND FAR
NORTHWESTERN SD. NORTHWESTERLY WINDS WILL INCREASE BEHIND THE FRONT
DURING THE LATE MORNING AND AFTERNOON...A BIT BREEZY AT TIMES OVER
THE WESTERN SD PLAINS. LINGERING SHOWERS SHOULD TAPER OFF QUICKLY IN
THE EVENING AS THE WAVE PUSHES EAST OF THE AREA.

&&

.LONG TERM...SATURDAY THROUGH THURSDAY
ISSUED AT 330 PM MDT THU AUG 28 2014

SATURDAY...SHORTWAVE RIDGE OVER THE CWA WILL QUICKLY MOVE INTO THE
MIDWEST DURING THE DAY AS A SHORTWAVE TROUGH ZIPS THROUGH MT INTO
ND/WY BY SATURDAY EVENING. SURFACE CYCLONE WILL DEVELOP OVER EASTERN
MT AND MOVES INTO THE CENTRAL DAKOTAS SATURDAY NIGHT. LOW LEVEL
MOISTURE CONVERGENCE ALONG THE FRONT WILL RESULT IN A NARROW BAND OF
1-2KJ/KG MLCAPE FROM SOUTHEAST MT INTO CENTRAL SD. 15-20M/S 0-6KM
BULK SHEAR SPREADS ACROSS NORTHWEST SD DURING PEAK HEATING. MLCIN
SHOULD BE BROKEN BY SURFACE FORCING AND LIFT AHEAD OF SHORTWAVE
RESULTING IN STRONG/POTENTIALLY SEVERE THUNDERSTORMS LATER SATURDAY
AFTERNOON INTO THE EVENING HOURS. STORMS MAY CONGEAL INTO A SMALL
MCS GIVEN DEVELOPING 50KT LOW LEVEL JET ACROSS THE EASTERN DAKOTAS
SATURDAY NIGHT. TEMPERATURES WILL BE TRICKY WITH VERY WARM READINGS
AHEAD OF THE LOW AND COOLER READINGS BEHIND THE FRONT.

SUNDAY THROUGH TUESDAY...UPPER TROUGH WITH EMBEDDED SHORTWAVES
SAUNTERS ACROSS THE DAKOTAS/SOUTH CENTRAL CANADA BRINGING SHRA/TSRA
CHANCES...ALTHOUGH COVERAGE SHOULD BE LOWER THAN RECENT MEMORY GIVEN
DRIER NORTHWEST FLOW. TEMPERATURES WILL BE NOTICEABLY COOLER SUNDAY
AND THEN WARM SLIGHTLY THROUGH TUESDAY.

WEDNESDAY/THURSDAY...UPPER RIDGE SHOULD BUILD INTO THE NORTHERN
PLAINS AS UPPER TROUGH DEEPENS OVER THE NORTHWEST US. DRIER AND
WARMER PATTERN MAY EVOLVE GIVEN THERMAL RIDGE AMPLIFICATION.

&&

.AVIATION...FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT
ISSUED AT 1108 PM MDT THU AUG 28 2014

MVFR CONDITIONS IN PATCHY FOG MAY DEVELOP OVER PARTS OF WESTERN
SOUTH DAKOTA LATE TONIGHT/EARLY FRIDAY MORNING. A BAND OF ISOLATED
TO SCATTERED SHOWERS AND THUNDERSTORMS WILL MOVE INTO NORTHEASTERN
WYOMING LATE TONIGHT AND WILL SPREAD EASTWARD INTO WESTERN SOUTH
DAKOTA ON FRIDAY MORNING. THUNDERSTORMS WILL INCREASE IN COVERAGE
OVER WESTERN AND CENTRAL SOUTH DAKOTA ON FRIDAY AFTERNOON.

&&

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

$$

SHORT TERM...26
LONG TERM...HELGESON
AVIATION...10






000
FXUS63 KUNR 290511
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
1111 PM MDT THU AUG 28 2014

.SHORT TERM...THIS EVENING THROUGH FRIDAY NIGHT
ISSUED AT 330 PM MDT THU AUG 28 2014

CURRENT SURFACE ANALYSIS SHOWS LOW PRESSURE OVER CENTRAL
NEB...WITH INVERTED TROF STRETCHING NORTHWARD ACROSS CENTRAL SD.
HIGH PRESSURE IS IN PLACE OVER THE CENTRAL ROCKIES. UPPER LEVEL
ANALYSIS SHOWS LOW NOW OVER FAR NORTHEAST CO...SLOWLY MOVING EAST-
SOUTHEAST. KUDX RADAR SHOWS ISOLATED TO SCATTERED SHOWERS FROM
CENTRAL SD TO FAR SOUTHWEST SD. THERE ARE A FEW LIGHTNING STRIKES
FROM TIME TO TIME WITH THE ACTIVITY OVER SOUTHERN SD. SKIES RANGE
FROM MOSTLY SUNNY OVER NORTHEAST WY AND FAR NORTHWEST SD TO MOSTLY
CLOUDY SOUTH AND EAST OF THE BLACK HILLS. TEMPS ARE IN THE 70S AND
LOWER 80S WITH LIGHT NORTHERLY WINDS IN MOST AREAS.

CONDITIONS WILL CONTINUE TO GRADUALLY IMPROVE THROUGH THE EVENING
FOR AREAS SOUTH AND EAST OF THE BLACK HILLS...WITH MOSTLY CLEAR
SKIES OVER WESTERN AND NORTHERN AREAS. HAVE ADDED CHANCES FOR
SHOWERS AND STORMS ACROSS SOUTH CENTRAL SD FOR THE EVENING HOURS AS
SYSTEM IS SLOWER TO MOVE OUT THAN WAS EXPECTED. WITH LOW LEVEL
MOISTURE HANGING AROUND OVER EASTERN PORTIONS OF THE CWA...HAVE KEPT
PATCHY FOG IN FOR MOST OF THE SD PLAINS. LOWS TONIGHT WILL BE IN THE
50S AND LOWER 60S. WINDS WILL MOSTLY BE LIGHT AND VARIABLE.

THE NEXT UPPER LEVEL WAVE...MUCH WEAKER THAN THE CURRENT ONE...WILL
MOVE QUICKLY INTO THE AREA ON FRIDAY...WITH INCREASING CHANCES FOR
SHOWERS AND THUNDERSTORMS THROUGH THE DAY FROM WEST TO EAST. A WEAK
COLD FRONT WILL ALSO SLIDE SOUTH INTO THE AREA WITH THE SHORTWAVE.
THE THREAT FOR SEVERE STORMS WILL REMAIN VERY LOW...BUT SUFFICIENT
INSTABILITY IS EXPECTED TO THE EAST OF THE BLACK HILLS IN THE
AFTERNOON TO POSSIBLY GET A STRONG STORM OR TWO GOING. HIGHS WILL BE
IN THE 80S...WITH SOME 70S ACROSS THE BLACK HILLS AND FAR
NORTHWESTERN SD. NORTHWESTERLY WINDS WILL INCREASE BEHIND THE FRONT
DURING THE LATE MORNING AND AFTERNOON...A BIT BREEZY AT TIMES OVER
THE WESTERN SD PLAINS. LINGERING SHOWERS SHOULD TAPER OFF QUICKLY IN
THE EVENING AS THE WAVE PUSHES EAST OF THE AREA.

&&

.LONG TERM...SATURDAY THROUGH THURSDAY
ISSUED AT 330 PM MDT THU AUG 28 2014

SATURDAY...SHORTWAVE RIDGE OVER THE CWA WILL QUICKLY MOVE INTO THE
MIDWEST DURING THE DAY AS A SHORTWAVE TROUGH ZIPS THROUGH MT INTO
ND/WY BY SATURDAY EVENING. SURFACE CYCLONE WILL DEVELOP OVER EASTERN
MT AND MOVES INTO THE CENTRAL DAKOTAS SATURDAY NIGHT. LOW LEVEL
MOISTURE CONVERGENCE ALONG THE FRONT WILL RESULT IN A NARROW BAND OF
1-2KJ/KG MLCAPE FROM SOUTHEAST MT INTO CENTRAL SD. 15-20M/S 0-6KM
BULK SHEAR SPREADS ACROSS NORTHWEST SD DURING PEAK HEATING. MLCIN
SHOULD BE BROKEN BY SURFACE FORCING AND LIFT AHEAD OF SHORTWAVE
RESULTING IN STRONG/POTENTIALLY SEVERE THUNDERSTORMS LATER SATURDAY
AFTERNOON INTO THE EVENING HOURS. STORMS MAY CONGEAL INTO A SMALL
MCS GIVEN DEVELOPING 50KT LOW LEVEL JET ACROSS THE EASTERN DAKOTAS
SATURDAY NIGHT. TEMPERATURES WILL BE TRICKY WITH VERY WARM READINGS
AHEAD OF THE LOW AND COOLER READINGS BEHIND THE FRONT.

SUNDAY THROUGH TUESDAY...UPPER TROUGH WITH EMBEDDED SHORTWAVES
SAUNTERS ACROSS THE DAKOTAS/SOUTH CENTRAL CANADA BRINGING SHRA/TSRA
CHANCES...ALTHOUGH COVERAGE SHOULD BE LOWER THAN RECENT MEMORY GIVEN
DRIER NORTHWEST FLOW. TEMPERATURES WILL BE NOTICEABLY COOLER SUNDAY
AND THEN WARM SLIGHTLY THROUGH TUESDAY.

WEDNESDAY/THURSDAY...UPPER RIDGE SHOULD BUILD INTO THE NORTHERN
PLAINS AS UPPER TROUGH DEEPENS OVER THE NORTHWEST US. DRIER AND
WARMER PATTERN MAY EVOLVE GIVEN THERMAL RIDGE AMPLIFICATION.

&&

.AVIATION...FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT
ISSUED AT 1108 PM MDT THU AUG 28 2014

MVFR CONDITIONS IN PATCHY FOG MAY DEVELOP OVER PARTS OF WESTERN
SOUTH DAKOTA LATE TONIGHT/EARLY FRIDAY MORNING. A BAND OF ISOLATED
TO SCATTERED SHOWERS AND THUNDERSTORMS WILL MOVE INTO NORTHEASTERN
WYOMING LATE TONIGHT AND WILL SPREAD EASTWARD INTO WESTERN SOUTH
DAKOTA ON FRIDAY MORNING. THUNDERSTORMS WILL INCREASE IN COVERAGE
OVER WESTERN AND CENTRAL SOUTH DAKOTA ON FRIDAY AFTERNOON.

&&

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

$$

SHORT TERM...26
LONG TERM...HELGESON
AVIATION...10






000
FXUS63 KUNR 290511
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
1111 PM MDT THU AUG 28 2014

.SHORT TERM...THIS EVENING THROUGH FRIDAY NIGHT
ISSUED AT 330 PM MDT THU AUG 28 2014

CURRENT SURFACE ANALYSIS SHOWS LOW PRESSURE OVER CENTRAL
NEB...WITH INVERTED TROF STRETCHING NORTHWARD ACROSS CENTRAL SD.
HIGH PRESSURE IS IN PLACE OVER THE CENTRAL ROCKIES. UPPER LEVEL
ANALYSIS SHOWS LOW NOW OVER FAR NORTHEAST CO...SLOWLY MOVING EAST-
SOUTHEAST. KUDX RADAR SHOWS ISOLATED TO SCATTERED SHOWERS FROM
CENTRAL SD TO FAR SOUTHWEST SD. THERE ARE A FEW LIGHTNING STRIKES
FROM TIME TO TIME WITH THE ACTIVITY OVER SOUTHERN SD. SKIES RANGE
FROM MOSTLY SUNNY OVER NORTHEAST WY AND FAR NORTHWEST SD TO MOSTLY
CLOUDY SOUTH AND EAST OF THE BLACK HILLS. TEMPS ARE IN THE 70S AND
LOWER 80S WITH LIGHT NORTHERLY WINDS IN MOST AREAS.

CONDITIONS WILL CONTINUE TO GRADUALLY IMPROVE THROUGH THE EVENING
FOR AREAS SOUTH AND EAST OF THE BLACK HILLS...WITH MOSTLY CLEAR
SKIES OVER WESTERN AND NORTHERN AREAS. HAVE ADDED CHANCES FOR
SHOWERS AND STORMS ACROSS SOUTH CENTRAL SD FOR THE EVENING HOURS AS
SYSTEM IS SLOWER TO MOVE OUT THAN WAS EXPECTED. WITH LOW LEVEL
MOISTURE HANGING AROUND OVER EASTERN PORTIONS OF THE CWA...HAVE KEPT
PATCHY FOG IN FOR MOST OF THE SD PLAINS. LOWS TONIGHT WILL BE IN THE
50S AND LOWER 60S. WINDS WILL MOSTLY BE LIGHT AND VARIABLE.

THE NEXT UPPER LEVEL WAVE...MUCH WEAKER THAN THE CURRENT ONE...WILL
MOVE QUICKLY INTO THE AREA ON FRIDAY...WITH INCREASING CHANCES FOR
SHOWERS AND THUNDERSTORMS THROUGH THE DAY FROM WEST TO EAST. A WEAK
COLD FRONT WILL ALSO SLIDE SOUTH INTO THE AREA WITH THE SHORTWAVE.
THE THREAT FOR SEVERE STORMS WILL REMAIN VERY LOW...BUT SUFFICIENT
INSTABILITY IS EXPECTED TO THE EAST OF THE BLACK HILLS IN THE
AFTERNOON TO POSSIBLY GET A STRONG STORM OR TWO GOING. HIGHS WILL BE
IN THE 80S...WITH SOME 70S ACROSS THE BLACK HILLS AND FAR
NORTHWESTERN SD. NORTHWESTERLY WINDS WILL INCREASE BEHIND THE FRONT
DURING THE LATE MORNING AND AFTERNOON...A BIT BREEZY AT TIMES OVER
THE WESTERN SD PLAINS. LINGERING SHOWERS SHOULD TAPER OFF QUICKLY IN
THE EVENING AS THE WAVE PUSHES EAST OF THE AREA.

&&

.LONG TERM...SATURDAY THROUGH THURSDAY
ISSUED AT 330 PM MDT THU AUG 28 2014

SATURDAY...SHORTWAVE RIDGE OVER THE CWA WILL QUICKLY MOVE INTO THE
MIDWEST DURING THE DAY AS A SHORTWAVE TROUGH ZIPS THROUGH MT INTO
ND/WY BY SATURDAY EVENING. SURFACE CYCLONE WILL DEVELOP OVER EASTERN
MT AND MOVES INTO THE CENTRAL DAKOTAS SATURDAY NIGHT. LOW LEVEL
MOISTURE CONVERGENCE ALONG THE FRONT WILL RESULT IN A NARROW BAND OF
1-2KJ/KG MLCAPE FROM SOUTHEAST MT INTO CENTRAL SD. 15-20M/S 0-6KM
BULK SHEAR SPREADS ACROSS NORTHWEST SD DURING PEAK HEATING. MLCIN
SHOULD BE BROKEN BY SURFACE FORCING AND LIFT AHEAD OF SHORTWAVE
RESULTING IN STRONG/POTENTIALLY SEVERE THUNDERSTORMS LATER SATURDAY
AFTERNOON INTO THE EVENING HOURS. STORMS MAY CONGEAL INTO A SMALL
MCS GIVEN DEVELOPING 50KT LOW LEVEL JET ACROSS THE EASTERN DAKOTAS
SATURDAY NIGHT. TEMPERATURES WILL BE TRICKY WITH VERY WARM READINGS
AHEAD OF THE LOW AND COOLER READINGS BEHIND THE FRONT.

SUNDAY THROUGH TUESDAY...UPPER TROUGH WITH EMBEDDED SHORTWAVES
SAUNTERS ACROSS THE DAKOTAS/SOUTH CENTRAL CANADA BRINGING SHRA/TSRA
CHANCES...ALTHOUGH COVERAGE SHOULD BE LOWER THAN RECENT MEMORY GIVEN
DRIER NORTHWEST FLOW. TEMPERATURES WILL BE NOTICEABLY COOLER SUNDAY
AND THEN WARM SLIGHTLY THROUGH TUESDAY.

WEDNESDAY/THURSDAY...UPPER RIDGE SHOULD BUILD INTO THE NORTHERN
PLAINS AS UPPER TROUGH DEEPENS OVER THE NORTHWEST US. DRIER AND
WARMER PATTERN MAY EVOLVE GIVEN THERMAL RIDGE AMPLIFICATION.

&&

.AVIATION...FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT
ISSUED AT 1108 PM MDT THU AUG 28 2014

MVFR CONDITIONS IN PATCHY FOG MAY DEVELOP OVER PARTS OF WESTERN
SOUTH DAKOTA LATE TONIGHT/EARLY FRIDAY MORNING. A BAND OF ISOLATED
TO SCATTERED SHOWERS AND THUNDERSTORMS WILL MOVE INTO NORTHEASTERN
WYOMING LATE TONIGHT AND WILL SPREAD EASTWARD INTO WESTERN SOUTH
DAKOTA ON FRIDAY MORNING. THUNDERSTORMS WILL INCREASE IN COVERAGE
OVER WESTERN AND CENTRAL SOUTH DAKOTA ON FRIDAY AFTERNOON.

&&

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

$$

SHORT TERM...26
LONG TERM...HELGESON
AVIATION...10






000
FXUS65 KCYS 290442
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
1042 PM MDT THU AUG 28 2014

.UPDATE...
ISSUED AT 1037 PM MDT THU AUG 28 2014

GRIDDED FORECASTS UPDATED FOR THE OVERNIGHT. ADDED PATCHY FOG TO
THE NORTH PLATTE RIVER VALLEY NEAR TORRINGTON...SCOTTSBLUFF AND
FURTHER EASTWARD AS TEMPERATURE AND DEWPOINT SPREADS ARE ONLY
2 DEGREES AT SCOTTSBLUFF AT 10 PM AND FORECAST SPREADS SHOULD ALSO
NARROW AT TORRINGTON PER NAM MODEL GUIDANCE...DESPITE THE 11 MICRON
SATELLITE IMAGERY NOT YET SHOWING ANY LOW CLOUD DEVELOPMENT ALONG
THE NORTH PLATTE RIVER VALLEY. BOUNDARY LOW LEVEL WEST WINDS WILL
LIMIT THE AREAL COVERAGE OF FOG DEVELOPMENT TO JUST ALONG THE
RIVER VALLEY. 10 PM TEMPERATURE AND DEWPOINT SPREADS ARE ONLY
3 DEGREES AT CHEYENNE AND KIMBALL...THOUGH LOW LEVEL WEST WINDS
EXPECTED TO MINIMIZE FOG PRODUCTION ALONG THE INTERSTATE 80
CORRIDOR. ALSO ADJUSTED MINIMUM TEMPERATURES...DEWPOINTS AND
CLOUD COVER OVERNIGHT BASED ON TRENDS.

UPDATE ISSUED AT 640 PM MDT THU AUG 28 2014

GRIDDED FORECASTS AND ZONE FORECASTS HAVE BEEN UPDATED TO REMOVE
ALL MENTION OF PRECIPITATION FOR THE REST OF THE NIGHT BASED ON
WSR-88D RADAR LOOPS FROM CHEYENNE...DENVER...GRAND JUNCTION...
RIVERTON AND RAPID CITY. ALSO DECREASED CLOUD COVER BASED ON
VISIBLE AND INFRARED SATELLITE IMAGERY LOOPS. TEMPERATURES...
DEWPOINTS AND WINDS ALSO ADJUSTED FOR THE REST OF THE NIGHT BASED
ON CURRENT TRENDS.

&&

.SHORT TERM...(THIS EVENING THROUGH SATURDAY NIGHT)
ISSUED AT 313 PM MDT THU AUG 28 2014

LIGHT TO MODERATE RAIN HAS BEEN ONGOING FOR MUCH OF THE DAY ACROSS
SOUTHEAST WY AND THE WESTERN NE PANHANDLE. THIS IS OCCURRING ON THE
BACK SIDE OF A VIGOROUS MIDLVL SHORTWAVE CURRENTLY EXITING THE AREA
TO THE EAST OVER NE. WIDESPREAD CLOUDS/PCPN HAS WREAKED HAVOC ON THE
FCST TODAY WITH TEMPS ONLY IN THE 50S AT LAR AND CYS. AFTN RADAR AND
SATELLITE IMAGERY SHOWS THIS ACTIVITY HAS DECREASED IN COVERAGE AS
OF 20Z...AND BELIEVE THIS TREND SHOULD CONTINUE THROUGH THE EARLY
EVE HOURS AS BETTER UPPER-LEVEL SUPPORT SHIFTS TO THE EAST AND IS
REPLACED BY SUBSIDENCE BENEATH A SHORTWAVE RIDGE AXIS. VISIBLE SAT
INDICATES SKIES ARE CLEARING OVER OUR WESTERN ZONES...SO EXPECT A
QUIET OVERNIGHT PERIOD FOR THE MOST PART WITH MORE CLOUDS OVER THE
PANHANDLE. RAIN SHOULD END COMPLETELY BY 03-06Z FRI. WENT A LITTLE
WARMER FOR LOWS TONIGHT FARTHER EAST WHERE RADIATIONAL COOLING WILL
BE LESS.

WARMING TREND ENSUES FOR FRI WITH BROAD UPPER-LEVEL RIDGING IN PLACE
OVER THE CWA. ECMWF H7 TEMPS INCREASE TO 10-12 DEG C ON FRI...SO IT
SHOULD BE QUITE A BIT WARMER WITH DRY/SUBSIDING CONDITIONS IN PLACE
ACROSS THE AREA AND NO MAJOR INHIBITING FACTORS FOR SOME DECENT SFC
HEATING. A QUICK SHOT OF MIDLVL MOISTURE WITH A WEAK WAVE TRAVERSING
THE FLOW SHOULD PRODUCE ISOLATED SHOWERS AND STORMS...GENERALLY IN
THE AFTN. GFS INSTABILITY PARAMETERS ARE UNIMPRESSIVE WITH LIS ONLY
AROUND -1 TO -2C AND LESS THAN 500 J/KG SBCAPE. CONVECTION ON FRI
SHOULD BE GARDEN VARIETY. SAT WILL BE THE WARMEST DAY OF THE PERIOD
AHEAD OF A MORE SIGNIFICANT SHORTWAVE MOVING ACROSS THE PAC NW. MID
LEVEL LAPSE RATES AROUND 8-9 DEG C/KM SUGGEST BETTER INSTABILITY ON
SAT...BETTER OVER THE PANHANDLE WHERE SURFACE CAPES MAY APPROACH
1000 J/KG. INCREASED POPS FOR SAT AFTN AND EVE WITH EXCELLENT MODEL
AGREEMENT BETWEEN THE GFS/NAM/ECMWF WITH INCREASING 700-500 MILLIBAR
QG ASCENT. GOOD CONVERGENCE ALONG THE COLD FRONT WILL HELP GENERATE
CONVECTION AS WELL. COLD FRONT BLASTS ACROSS THE CWA ON SAT AFTN AND
EARLY EVE...ENHANCING PCPN CHANCES AND SETTING THE STAGE FOR A COOL
START TO THE EXTENDED PERIOD. IT WILL BE BREEZY AS WELL WITH 35 KTS
OF FLOW AT H7...ESPECIALLY ALONG AND WEST OF THE LARAMIE RANGE ON
SAT AFTN.

.LONG TERM...(SUNDAY THROUGH THURSDAY)
ISSUED AT 313 PM MDT THU AUG 28 2014

A RELATIVELY COOL AND UNSETTLED END OF THE WEEKEND EXPECTED AS AN
UPPER TROUGH AND ASSOCIATED SFC FRONT MOVES THRU. THE ECMWF IS
6-12 HOURS QUICKER WITH FROPA MOVING IT THRU AT THE END OF THE
PREVIOUS PERIOD. COMPARATIVELY...THE GFS HOLDS IT BACK UNTIL LATER
SUNDAY. IN EITHER CASE...EXPECT AT LEAST SOME CONVECTIVE
DEVELOPMENT SUNDAY...WITH BEST COVERAGE DURING THE LATE AFTERNOON
AND OVR THE NRN NEBRASKA PANHANDLE. TROUGH AXIS WILL CLEAR THE
AREA SUNDAY NIGHT AND WHEN COMBINED WITH NIGHTTIME STABILIZATION
WILL BRING AN END TO SHOWER/THUNDERSTORM CHANCES BY NIGHTFALL.
ANOTHER FAST MOVING SHORTWAVE WILL TRACK ACROSS THE AREA AGAIN ON
MONDAY. THERE MAY BE JUST ENOUGH MOISTURE/INSTABILITY TO INITIATE
AN ISOLATED SHOWER/STORM LATE MONDAY AFTERNOON OR EARLY MONDAY
EVENING EAST OF A CHADRON TO ALLIANCE LINE. A MUCH DRIER AIR MASS
WILL ADVECT IN TUE-THU ALLOWING A LLVL THERMAL RIDGE TO AMPLIFY.
THE RESULT WILL BE FOR DRY AND WARMER CONDITIONS. SUNDAY WILL BE
THE COOLEST DAY OF THE PERIOD IN THE COOL POST-FRONTAL AIR MASS.
PROGD H7 TEMPS ONLY REACH AROUND 8C...WHICH WILL KEEP AFTERNOON
TEMPS IN THE 60S AND 70S. H7 TEMPS WILL RETURN TO 12-16C FOR MON-
THU...BRINGING HIGH TEMPS BACK WELL INTO THE 70S WEST AND 80S TO
NR 90S EAST BY WED-THU.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z FRIDAY AFTERNOON)
ISSUED AT 455 PM MDT THU AUG 28 2014

LOW PRESSURE THAT BROUGHT THE WIDESPREAD RAIN IS MOVING OFF TO THE
EAST. STILL SOME SHOWERS FOR AN HOUR OR SO OUT IN THE PANHANDLE
THAT SHOULD END EARLY THIS EVENING. WESTERLY WINDS WILL BRING
DOWNSLOPING CONDITIONS FRIDAY...WHICH WILL GIVE THE AREA VFR
CONDITIONS.


&&

.FIRE WEATHER...
ISSUED AT 313 PM MDT THU AUG 28 2014

NO MAJOR FIRE WEATHER CONCERNS OVER THE NEXT FEW DAYS. THE WEATHER
SYSTEM RESPONSIBLE FOR THE RECENT RAINFALL WILL MOVE TO THE EAST OF
THE AREA TONIGHT...GIVING WAY TO A GRADUAL WARMING TREND ON FRI AND
SAT. MINIMUM RELATIVE HUMIDITY VALUES WILL BE IN THE UPPER TEENS OR
LOW 20S FOR WESTERN ZONES. AFTERNOON SHOWERS AND THUNDERSTORMS MAY
PRODUCE GUSTY AND ERRATIC WINDS THROUGH THE REST OF THE WEEK...BUT
IN GENERAL STRONG STORMS ARE NOT EXPECTED. A STRONG COLD FRONT WILL
MOVE FROM WEST TO EAST ACROSS THE AREA ON SAT AFTN...GIVING WAY TO
BREEZY CONDITIONS WITH WIND GUSTS UP TO 40 MPH OVER PARTS OF CARBON
COUNTY. COOLER TEMPERATURES WILL FOLLOW FOR SUN.

&&

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

$$

UPDATE...RUBIN
SHORT TERM...HAMMER
LONG TERM...HAHN
AVIATION...CLAYCOMB
FIRE WEATHER...HAMMER







000
FXUS65 KCYS 290442
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
1042 PM MDT THU AUG 28 2014

.UPDATE...
ISSUED AT 1037 PM MDT THU AUG 28 2014

GRIDDED FORECASTS UPDATED FOR THE OVERNIGHT. ADDED PATCHY FOG TO
THE NORTH PLATTE RIVER VALLEY NEAR TORRINGTON...SCOTTSBLUFF AND
FURTHER EASTWARD AS TEMPERATURE AND DEWPOINT SPREADS ARE ONLY
2 DEGREES AT SCOTTSBLUFF AT 10 PM AND FORECAST SPREADS SHOULD ALSO
NARROW AT TORRINGTON PER NAM MODEL GUIDANCE...DESPITE THE 11 MICRON
SATELLITE IMAGERY NOT YET SHOWING ANY LOW CLOUD DEVELOPMENT ALONG
THE NORTH PLATTE RIVER VALLEY. BOUNDARY LOW LEVEL WEST WINDS WILL
LIMIT THE AREAL COVERAGE OF FOG DEVELOPMENT TO JUST ALONG THE
RIVER VALLEY. 10 PM TEMPERATURE AND DEWPOINT SPREADS ARE ONLY
3 DEGREES AT CHEYENNE AND KIMBALL...THOUGH LOW LEVEL WEST WINDS
EXPECTED TO MINIMIZE FOG PRODUCTION ALONG THE INTERSTATE 80
CORRIDOR. ALSO ADJUSTED MINIMUM TEMPERATURES...DEWPOINTS AND
CLOUD COVER OVERNIGHT BASED ON TRENDS.

UPDATE ISSUED AT 640 PM MDT THU AUG 28 2014

GRIDDED FORECASTS AND ZONE FORECASTS HAVE BEEN UPDATED TO REMOVE
ALL MENTION OF PRECIPITATION FOR THE REST OF THE NIGHT BASED ON
WSR-88D RADAR LOOPS FROM CHEYENNE...DENVER...GRAND JUNCTION...
RIVERTON AND RAPID CITY. ALSO DECREASED CLOUD COVER BASED ON
VISIBLE AND INFRARED SATELLITE IMAGERY LOOPS. TEMPERATURES...
DEWPOINTS AND WINDS ALSO ADJUSTED FOR THE REST OF THE NIGHT BASED
ON CURRENT TRENDS.

&&

.SHORT TERM...(THIS EVENING THROUGH SATURDAY NIGHT)
ISSUED AT 313 PM MDT THU AUG 28 2014

LIGHT TO MODERATE RAIN HAS BEEN ONGOING FOR MUCH OF THE DAY ACROSS
SOUTHEAST WY AND THE WESTERN NE PANHANDLE. THIS IS OCCURRING ON THE
BACK SIDE OF A VIGOROUS MIDLVL SHORTWAVE CURRENTLY EXITING THE AREA
TO THE EAST OVER NE. WIDESPREAD CLOUDS/PCPN HAS WREAKED HAVOC ON THE
FCST TODAY WITH TEMPS ONLY IN THE 50S AT LAR AND CYS. AFTN RADAR AND
SATELLITE IMAGERY SHOWS THIS ACTIVITY HAS DECREASED IN COVERAGE AS
OF 20Z...AND BELIEVE THIS TREND SHOULD CONTINUE THROUGH THE EARLY
EVE HOURS AS BETTER UPPER-LEVEL SUPPORT SHIFTS TO THE EAST AND IS
REPLACED BY SUBSIDENCE BENEATH A SHORTWAVE RIDGE AXIS. VISIBLE SAT
INDICATES SKIES ARE CLEARING OVER OUR WESTERN ZONES...SO EXPECT A
QUIET OVERNIGHT PERIOD FOR THE MOST PART WITH MORE CLOUDS OVER THE
PANHANDLE. RAIN SHOULD END COMPLETELY BY 03-06Z FRI. WENT A LITTLE
WARMER FOR LOWS TONIGHT FARTHER EAST WHERE RADIATIONAL COOLING WILL
BE LESS.

WARMING TREND ENSUES FOR FRI WITH BROAD UPPER-LEVEL RIDGING IN PLACE
OVER THE CWA. ECMWF H7 TEMPS INCREASE TO 10-12 DEG C ON FRI...SO IT
SHOULD BE QUITE A BIT WARMER WITH DRY/SUBSIDING CONDITIONS IN PLACE
ACROSS THE AREA AND NO MAJOR INHIBITING FACTORS FOR SOME DECENT SFC
HEATING. A QUICK SHOT OF MIDLVL MOISTURE WITH A WEAK WAVE TRAVERSING
THE FLOW SHOULD PRODUCE ISOLATED SHOWERS AND STORMS...GENERALLY IN
THE AFTN. GFS INSTABILITY PARAMETERS ARE UNIMPRESSIVE WITH LIS ONLY
AROUND -1 TO -2C AND LESS THAN 500 J/KG SBCAPE. CONVECTION ON FRI
SHOULD BE GARDEN VARIETY. SAT WILL BE THE WARMEST DAY OF THE PERIOD
AHEAD OF A MORE SIGNIFICANT SHORTWAVE MOVING ACROSS THE PAC NW. MID
LEVEL LAPSE RATES AROUND 8-9 DEG C/KM SUGGEST BETTER INSTABILITY ON
SAT...BETTER OVER THE PANHANDLE WHERE SURFACE CAPES MAY APPROACH
1000 J/KG. INCREASED POPS FOR SAT AFTN AND EVE WITH EXCELLENT MODEL
AGREEMENT BETWEEN THE GFS/NAM/ECMWF WITH INCREASING 700-500 MILLIBAR
QG ASCENT. GOOD CONVERGENCE ALONG THE COLD FRONT WILL HELP GENERATE
CONVECTION AS WELL. COLD FRONT BLASTS ACROSS THE CWA ON SAT AFTN AND
EARLY EVE...ENHANCING PCPN CHANCES AND SETTING THE STAGE FOR A COOL
START TO THE EXTENDED PERIOD. IT WILL BE BREEZY AS WELL WITH 35 KTS
OF FLOW AT H7...ESPECIALLY ALONG AND WEST OF THE LARAMIE RANGE ON
SAT AFTN.

.LONG TERM...(SUNDAY THROUGH THURSDAY)
ISSUED AT 313 PM MDT THU AUG 28 2014

A RELATIVELY COOL AND UNSETTLED END OF THE WEEKEND EXPECTED AS AN
UPPER TROUGH AND ASSOCIATED SFC FRONT MOVES THRU. THE ECMWF IS
6-12 HOURS QUICKER WITH FROPA MOVING IT THRU AT THE END OF THE
PREVIOUS PERIOD. COMPARATIVELY...THE GFS HOLDS IT BACK UNTIL LATER
SUNDAY. IN EITHER CASE...EXPECT AT LEAST SOME CONVECTIVE
DEVELOPMENT SUNDAY...WITH BEST COVERAGE DURING THE LATE AFTERNOON
AND OVR THE NRN NEBRASKA PANHANDLE. TROUGH AXIS WILL CLEAR THE
AREA SUNDAY NIGHT AND WHEN COMBINED WITH NIGHTTIME STABILIZATION
WILL BRING AN END TO SHOWER/THUNDERSTORM CHANCES BY NIGHTFALL.
ANOTHER FAST MOVING SHORTWAVE WILL TRACK ACROSS THE AREA AGAIN ON
MONDAY. THERE MAY BE JUST ENOUGH MOISTURE/INSTABILITY TO INITIATE
AN ISOLATED SHOWER/STORM LATE MONDAY AFTERNOON OR EARLY MONDAY
EVENING EAST OF A CHADRON TO ALLIANCE LINE. A MUCH DRIER AIR MASS
WILL ADVECT IN TUE-THU ALLOWING A LLVL THERMAL RIDGE TO AMPLIFY.
THE RESULT WILL BE FOR DRY AND WARMER CONDITIONS. SUNDAY WILL BE
THE COOLEST DAY OF THE PERIOD IN THE COOL POST-FRONTAL AIR MASS.
PROGD H7 TEMPS ONLY REACH AROUND 8C...WHICH WILL KEEP AFTERNOON
TEMPS IN THE 60S AND 70S. H7 TEMPS WILL RETURN TO 12-16C FOR MON-
THU...BRINGING HIGH TEMPS BACK WELL INTO THE 70S WEST AND 80S TO
NR 90S EAST BY WED-THU.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z FRIDAY AFTERNOON)
ISSUED AT 455 PM MDT THU AUG 28 2014

LOW PRESSURE THAT BROUGHT THE WIDESPREAD RAIN IS MOVING OFF TO THE
EAST. STILL SOME SHOWERS FOR AN HOUR OR SO OUT IN THE PANHANDLE
THAT SHOULD END EARLY THIS EVENING. WESTERLY WINDS WILL BRING
DOWNSLOPING CONDITIONS FRIDAY...WHICH WILL GIVE THE AREA VFR
CONDITIONS.


&&

.FIRE WEATHER...
ISSUED AT 313 PM MDT THU AUG 28 2014

NO MAJOR FIRE WEATHER CONCERNS OVER THE NEXT FEW DAYS. THE WEATHER
SYSTEM RESPONSIBLE FOR THE RECENT RAINFALL WILL MOVE TO THE EAST OF
THE AREA TONIGHT...GIVING WAY TO A GRADUAL WARMING TREND ON FRI AND
SAT. MINIMUM RELATIVE HUMIDITY VALUES WILL BE IN THE UPPER TEENS OR
LOW 20S FOR WESTERN ZONES. AFTERNOON SHOWERS AND THUNDERSTORMS MAY
PRODUCE GUSTY AND ERRATIC WINDS THROUGH THE REST OF THE WEEK...BUT
IN GENERAL STRONG STORMS ARE NOT EXPECTED. A STRONG COLD FRONT WILL
MOVE FROM WEST TO EAST ACROSS THE AREA ON SAT AFTN...GIVING WAY TO
BREEZY CONDITIONS WITH WIND GUSTS UP TO 40 MPH OVER PARTS OF CARBON
COUNTY. COOLER TEMPERATURES WILL FOLLOW FOR SUN.

&&

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

$$

UPDATE...RUBIN
SHORT TERM...HAMMER
LONG TERM...HAHN
AVIATION...CLAYCOMB
FIRE WEATHER...HAMMER







000
FXUS65 KCYS 290442
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
1042 PM MDT THU AUG 28 2014

.UPDATE...
ISSUED AT 1037 PM MDT THU AUG 28 2014

GRIDDED FORECASTS UPDATED FOR THE OVERNIGHT. ADDED PATCHY FOG TO
THE NORTH PLATTE RIVER VALLEY NEAR TORRINGTON...SCOTTSBLUFF AND
FURTHER EASTWARD AS TEMPERATURE AND DEWPOINT SPREADS ARE ONLY
2 DEGREES AT SCOTTSBLUFF AT 10 PM AND FORECAST SPREADS SHOULD ALSO
NARROW AT TORRINGTON PER NAM MODEL GUIDANCE...DESPITE THE 11 MICRON
SATELLITE IMAGERY NOT YET SHOWING ANY LOW CLOUD DEVELOPMENT ALONG
THE NORTH PLATTE RIVER VALLEY. BOUNDARY LOW LEVEL WEST WINDS WILL
LIMIT THE AREAL COVERAGE OF FOG DEVELOPMENT TO JUST ALONG THE
RIVER VALLEY. 10 PM TEMPERATURE AND DEWPOINT SPREADS ARE ONLY
3 DEGREES AT CHEYENNE AND KIMBALL...THOUGH LOW LEVEL WEST WINDS
EXPECTED TO MINIMIZE FOG PRODUCTION ALONG THE INTERSTATE 80
CORRIDOR. ALSO ADJUSTED MINIMUM TEMPERATURES...DEWPOINTS AND
CLOUD COVER OVERNIGHT BASED ON TRENDS.

UPDATE ISSUED AT 640 PM MDT THU AUG 28 2014

GRIDDED FORECASTS AND ZONE FORECASTS HAVE BEEN UPDATED TO REMOVE
ALL MENTION OF PRECIPITATION FOR THE REST OF THE NIGHT BASED ON
WSR-88D RADAR LOOPS FROM CHEYENNE...DENVER...GRAND JUNCTION...
RIVERTON AND RAPID CITY. ALSO DECREASED CLOUD COVER BASED ON
VISIBLE AND INFRARED SATELLITE IMAGERY LOOPS. TEMPERATURES...
DEWPOINTS AND WINDS ALSO ADJUSTED FOR THE REST OF THE NIGHT BASED
ON CURRENT TRENDS.

&&

.SHORT TERM...(THIS EVENING THROUGH SATURDAY NIGHT)
ISSUED AT 313 PM MDT THU AUG 28 2014

LIGHT TO MODERATE RAIN HAS BEEN ONGOING FOR MUCH OF THE DAY ACROSS
SOUTHEAST WY AND THE WESTERN NE PANHANDLE. THIS IS OCCURRING ON THE
BACK SIDE OF A VIGOROUS MIDLVL SHORTWAVE CURRENTLY EXITING THE AREA
TO THE EAST OVER NE. WIDESPREAD CLOUDS/PCPN HAS WREAKED HAVOC ON THE
FCST TODAY WITH TEMPS ONLY IN THE 50S AT LAR AND CYS. AFTN RADAR AND
SATELLITE IMAGERY SHOWS THIS ACTIVITY HAS DECREASED IN COVERAGE AS
OF 20Z...AND BELIEVE THIS TREND SHOULD CONTINUE THROUGH THE EARLY
EVE HOURS AS BETTER UPPER-LEVEL SUPPORT SHIFTS TO THE EAST AND IS
REPLACED BY SUBSIDENCE BENEATH A SHORTWAVE RIDGE AXIS. VISIBLE SAT
INDICATES SKIES ARE CLEARING OVER OUR WESTERN ZONES...SO EXPECT A
QUIET OVERNIGHT PERIOD FOR THE MOST PART WITH MORE CLOUDS OVER THE
PANHANDLE. RAIN SHOULD END COMPLETELY BY 03-06Z FRI. WENT A LITTLE
WARMER FOR LOWS TONIGHT FARTHER EAST WHERE RADIATIONAL COOLING WILL
BE LESS.

WARMING TREND ENSUES FOR FRI WITH BROAD UPPER-LEVEL RIDGING IN PLACE
OVER THE CWA. ECMWF H7 TEMPS INCREASE TO 10-12 DEG C ON FRI...SO IT
SHOULD BE QUITE A BIT WARMER WITH DRY/SUBSIDING CONDITIONS IN PLACE
ACROSS THE AREA AND NO MAJOR INHIBITING FACTORS FOR SOME DECENT SFC
HEATING. A QUICK SHOT OF MIDLVL MOISTURE WITH A WEAK WAVE TRAVERSING
THE FLOW SHOULD PRODUCE ISOLATED SHOWERS AND STORMS...GENERALLY IN
THE AFTN. GFS INSTABILITY PARAMETERS ARE UNIMPRESSIVE WITH LIS ONLY
AROUND -1 TO -2C AND LESS THAN 500 J/KG SBCAPE. CONVECTION ON FRI
SHOULD BE GARDEN VARIETY. SAT WILL BE THE WARMEST DAY OF THE PERIOD
AHEAD OF A MORE SIGNIFICANT SHORTWAVE MOVING ACROSS THE PAC NW. MID
LEVEL LAPSE RATES AROUND 8-9 DEG C/KM SUGGEST BETTER INSTABILITY ON
SAT...BETTER OVER THE PANHANDLE WHERE SURFACE CAPES MAY APPROACH
1000 J/KG. INCREASED POPS FOR SAT AFTN AND EVE WITH EXCELLENT MODEL
AGREEMENT BETWEEN THE GFS/NAM/ECMWF WITH INCREASING 700-500 MILLIBAR
QG ASCENT. GOOD CONVERGENCE ALONG THE COLD FRONT WILL HELP GENERATE
CONVECTION AS WELL. COLD FRONT BLASTS ACROSS THE CWA ON SAT AFTN AND
EARLY EVE...ENHANCING PCPN CHANCES AND SETTING THE STAGE FOR A COOL
START TO THE EXTENDED PERIOD. IT WILL BE BREEZY AS WELL WITH 35 KTS
OF FLOW AT H7...ESPECIALLY ALONG AND WEST OF THE LARAMIE RANGE ON
SAT AFTN.

.LONG TERM...(SUNDAY THROUGH THURSDAY)
ISSUED AT 313 PM MDT THU AUG 28 2014

A RELATIVELY COOL AND UNSETTLED END OF THE WEEKEND EXPECTED AS AN
UPPER TROUGH AND ASSOCIATED SFC FRONT MOVES THRU. THE ECMWF IS
6-12 HOURS QUICKER WITH FROPA MOVING IT THRU AT THE END OF THE
PREVIOUS PERIOD. COMPARATIVELY...THE GFS HOLDS IT BACK UNTIL LATER
SUNDAY. IN EITHER CASE...EXPECT AT LEAST SOME CONVECTIVE
DEVELOPMENT SUNDAY...WITH BEST COVERAGE DURING THE LATE AFTERNOON
AND OVR THE NRN NEBRASKA PANHANDLE. TROUGH AXIS WILL CLEAR THE
AREA SUNDAY NIGHT AND WHEN COMBINED WITH NIGHTTIME STABILIZATION
WILL BRING AN END TO SHOWER/THUNDERSTORM CHANCES BY NIGHTFALL.
ANOTHER FAST MOVING SHORTWAVE WILL TRACK ACROSS THE AREA AGAIN ON
MONDAY. THERE MAY BE JUST ENOUGH MOISTURE/INSTABILITY TO INITIATE
AN ISOLATED SHOWER/STORM LATE MONDAY AFTERNOON OR EARLY MONDAY
EVENING EAST OF A CHADRON TO ALLIANCE LINE. A MUCH DRIER AIR MASS
WILL ADVECT IN TUE-THU ALLOWING A LLVL THERMAL RIDGE TO AMPLIFY.
THE RESULT WILL BE FOR DRY AND WARMER CONDITIONS. SUNDAY WILL BE
THE COOLEST DAY OF THE PERIOD IN THE COOL POST-FRONTAL AIR MASS.
PROGD H7 TEMPS ONLY REACH AROUND 8C...WHICH WILL KEEP AFTERNOON
TEMPS IN THE 60S AND 70S. H7 TEMPS WILL RETURN TO 12-16C FOR MON-
THU...BRINGING HIGH TEMPS BACK WELL INTO THE 70S WEST AND 80S TO
NR 90S EAST BY WED-THU.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z FRIDAY AFTERNOON)
ISSUED AT 455 PM MDT THU AUG 28 2014

LOW PRESSURE THAT BROUGHT THE WIDESPREAD RAIN IS MOVING OFF TO THE
EAST. STILL SOME SHOWERS FOR AN HOUR OR SO OUT IN THE PANHANDLE
THAT SHOULD END EARLY THIS EVENING. WESTERLY WINDS WILL BRING
DOWNSLOPING CONDITIONS FRIDAY...WHICH WILL GIVE THE AREA VFR
CONDITIONS.


&&

.FIRE WEATHER...
ISSUED AT 313 PM MDT THU AUG 28 2014

NO MAJOR FIRE WEATHER CONCERNS OVER THE NEXT FEW DAYS. THE WEATHER
SYSTEM RESPONSIBLE FOR THE RECENT RAINFALL WILL MOVE TO THE EAST OF
THE AREA TONIGHT...GIVING WAY TO A GRADUAL WARMING TREND ON FRI AND
SAT. MINIMUM RELATIVE HUMIDITY VALUES WILL BE IN THE UPPER TEENS OR
LOW 20S FOR WESTERN ZONES. AFTERNOON SHOWERS AND THUNDERSTORMS MAY
PRODUCE GUSTY AND ERRATIC WINDS THROUGH THE REST OF THE WEEK...BUT
IN GENERAL STRONG STORMS ARE NOT EXPECTED. A STRONG COLD FRONT WILL
MOVE FROM WEST TO EAST ACROSS THE AREA ON SAT AFTN...GIVING WAY TO
BREEZY CONDITIONS WITH WIND GUSTS UP TO 40 MPH OVER PARTS OF CARBON
COUNTY. COOLER TEMPERATURES WILL FOLLOW FOR SUN.

&&

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

$$

UPDATE...RUBIN
SHORT TERM...HAMMER
LONG TERM...HAHN
AVIATION...CLAYCOMB
FIRE WEATHER...HAMMER







000
FXUS65 KCYS 290442
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
1042 PM MDT THU AUG 28 2014

.UPDATE...
ISSUED AT 1037 PM MDT THU AUG 28 2014

GRIDDED FORECASTS UPDATED FOR THE OVERNIGHT. ADDED PATCHY FOG TO
THE NORTH PLATTE RIVER VALLEY NEAR TORRINGTON...SCOTTSBLUFF AND
FURTHER EASTWARD AS TEMPERATURE AND DEWPOINT SPREADS ARE ONLY
2 DEGREES AT SCOTTSBLUFF AT 10 PM AND FORECAST SPREADS SHOULD ALSO
NARROW AT TORRINGTON PER NAM MODEL GUIDANCE...DESPITE THE 11 MICRON
SATELLITE IMAGERY NOT YET SHOWING ANY LOW CLOUD DEVELOPMENT ALONG
THE NORTH PLATTE RIVER VALLEY. BOUNDARY LOW LEVEL WEST WINDS WILL
LIMIT THE AREAL COVERAGE OF FOG DEVELOPMENT TO JUST ALONG THE
RIVER VALLEY. 10 PM TEMPERATURE AND DEWPOINT SPREADS ARE ONLY
3 DEGREES AT CHEYENNE AND KIMBALL...THOUGH LOW LEVEL WEST WINDS
EXPECTED TO MINIMIZE FOG PRODUCTION ALONG THE INTERSTATE 80
CORRIDOR. ALSO ADJUSTED MINIMUM TEMPERATURES...DEWPOINTS AND
CLOUD COVER OVERNIGHT BASED ON TRENDS.

UPDATE ISSUED AT 640 PM MDT THU AUG 28 2014

GRIDDED FORECASTS AND ZONE FORECASTS HAVE BEEN UPDATED TO REMOVE
ALL MENTION OF PRECIPITATION FOR THE REST OF THE NIGHT BASED ON
WSR-88D RADAR LOOPS FROM CHEYENNE...DENVER...GRAND JUNCTION...
RIVERTON AND RAPID CITY. ALSO DECREASED CLOUD COVER BASED ON
VISIBLE AND INFRARED SATELLITE IMAGERY LOOPS. TEMPERATURES...
DEWPOINTS AND WINDS ALSO ADJUSTED FOR THE REST OF THE NIGHT BASED
ON CURRENT TRENDS.

&&

.SHORT TERM...(THIS EVENING THROUGH SATURDAY NIGHT)
ISSUED AT 313 PM MDT THU AUG 28 2014

LIGHT TO MODERATE RAIN HAS BEEN ONGOING FOR MUCH OF THE DAY ACROSS
SOUTHEAST WY AND THE WESTERN NE PANHANDLE. THIS IS OCCURRING ON THE
BACK SIDE OF A VIGOROUS MIDLVL SHORTWAVE CURRENTLY EXITING THE AREA
TO THE EAST OVER NE. WIDESPREAD CLOUDS/PCPN HAS WREAKED HAVOC ON THE
FCST TODAY WITH TEMPS ONLY IN THE 50S AT LAR AND CYS. AFTN RADAR AND
SATELLITE IMAGERY SHOWS THIS ACTIVITY HAS DECREASED IN COVERAGE AS
OF 20Z...AND BELIEVE THIS TREND SHOULD CONTINUE THROUGH THE EARLY
EVE HOURS AS BETTER UPPER-LEVEL SUPPORT SHIFTS TO THE EAST AND IS
REPLACED BY SUBSIDENCE BENEATH A SHORTWAVE RIDGE AXIS. VISIBLE SAT
INDICATES SKIES ARE CLEARING OVER OUR WESTERN ZONES...SO EXPECT A
QUIET OVERNIGHT PERIOD FOR THE MOST PART WITH MORE CLOUDS OVER THE
PANHANDLE. RAIN SHOULD END COMPLETELY BY 03-06Z FRI. WENT A LITTLE
WARMER FOR LOWS TONIGHT FARTHER EAST WHERE RADIATIONAL COOLING WILL
BE LESS.

WARMING TREND ENSUES FOR FRI WITH BROAD UPPER-LEVEL RIDGING IN PLACE
OVER THE CWA. ECMWF H7 TEMPS INCREASE TO 10-12 DEG C ON FRI...SO IT
SHOULD BE QUITE A BIT WARMER WITH DRY/SUBSIDING CONDITIONS IN PLACE
ACROSS THE AREA AND NO MAJOR INHIBITING FACTORS FOR SOME DECENT SFC
HEATING. A QUICK SHOT OF MIDLVL MOISTURE WITH A WEAK WAVE TRAVERSING
THE FLOW SHOULD PRODUCE ISOLATED SHOWERS AND STORMS...GENERALLY IN
THE AFTN. GFS INSTABILITY PARAMETERS ARE UNIMPRESSIVE WITH LIS ONLY
AROUND -1 TO -2C AND LESS THAN 500 J/KG SBCAPE. CONVECTION ON FRI
SHOULD BE GARDEN VARIETY. SAT WILL BE THE WARMEST DAY OF THE PERIOD
AHEAD OF A MORE SIGNIFICANT SHORTWAVE MOVING ACROSS THE PAC NW. MID
LEVEL LAPSE RATES AROUND 8-9 DEG C/KM SUGGEST BETTER INSTABILITY ON
SAT...BETTER OVER THE PANHANDLE WHERE SURFACE CAPES MAY APPROACH
1000 J/KG. INCREASED POPS FOR SAT AFTN AND EVE WITH EXCELLENT MODEL
AGREEMENT BETWEEN THE GFS/NAM/ECMWF WITH INCREASING 700-500 MILLIBAR
QG ASCENT. GOOD CONVERGENCE ALONG THE COLD FRONT WILL HELP GENERATE
CONVECTION AS WELL. COLD FRONT BLASTS ACROSS THE CWA ON SAT AFTN AND
EARLY EVE...ENHANCING PCPN CHANCES AND SETTING THE STAGE FOR A COOL
START TO THE EXTENDED PERIOD. IT WILL BE BREEZY AS WELL WITH 35 KTS
OF FLOW AT H7...ESPECIALLY ALONG AND WEST OF THE LARAMIE RANGE ON
SAT AFTN.

.LONG TERM...(SUNDAY THROUGH THURSDAY)
ISSUED AT 313 PM MDT THU AUG 28 2014

A RELATIVELY COOL AND UNSETTLED END OF THE WEEKEND EXPECTED AS AN
UPPER TROUGH AND ASSOCIATED SFC FRONT MOVES THRU. THE ECMWF IS
6-12 HOURS QUICKER WITH FROPA MOVING IT THRU AT THE END OF THE
PREVIOUS PERIOD. COMPARATIVELY...THE GFS HOLDS IT BACK UNTIL LATER
SUNDAY. IN EITHER CASE...EXPECT AT LEAST SOME CONVECTIVE
DEVELOPMENT SUNDAY...WITH BEST COVERAGE DURING THE LATE AFTERNOON
AND OVR THE NRN NEBRASKA PANHANDLE. TROUGH AXIS WILL CLEAR THE
AREA SUNDAY NIGHT AND WHEN COMBINED WITH NIGHTTIME STABILIZATION
WILL BRING AN END TO SHOWER/THUNDERSTORM CHANCES BY NIGHTFALL.
ANOTHER FAST MOVING SHORTWAVE WILL TRACK ACROSS THE AREA AGAIN ON
MONDAY. THERE MAY BE JUST ENOUGH MOISTURE/INSTABILITY TO INITIATE
AN ISOLATED SHOWER/STORM LATE MONDAY AFTERNOON OR EARLY MONDAY
EVENING EAST OF A CHADRON TO ALLIANCE LINE. A MUCH DRIER AIR MASS
WILL ADVECT IN TUE-THU ALLOWING A LLVL THERMAL RIDGE TO AMPLIFY.
THE RESULT WILL BE FOR DRY AND WARMER CONDITIONS. SUNDAY WILL BE
THE COOLEST DAY OF THE PERIOD IN THE COOL POST-FRONTAL AIR MASS.
PROGD H7 TEMPS ONLY REACH AROUND 8C...WHICH WILL KEEP AFTERNOON
TEMPS IN THE 60S AND 70S. H7 TEMPS WILL RETURN TO 12-16C FOR MON-
THU...BRINGING HIGH TEMPS BACK WELL INTO THE 70S WEST AND 80S TO
NR 90S EAST BY WED-THU.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z FRIDAY AFTERNOON)
ISSUED AT 455 PM MDT THU AUG 28 2014

LOW PRESSURE THAT BROUGHT THE WIDESPREAD RAIN IS MOVING OFF TO THE
EAST. STILL SOME SHOWERS FOR AN HOUR OR SO OUT IN THE PANHANDLE
THAT SHOULD END EARLY THIS EVENING. WESTERLY WINDS WILL BRING
DOWNSLOPING CONDITIONS FRIDAY...WHICH WILL GIVE THE AREA VFR
CONDITIONS.


&&

.FIRE WEATHER...
ISSUED AT 313 PM MDT THU AUG 28 2014

NO MAJOR FIRE WEATHER CONCERNS OVER THE NEXT FEW DAYS. THE WEATHER
SYSTEM RESPONSIBLE FOR THE RECENT RAINFALL WILL MOVE TO THE EAST OF
THE AREA TONIGHT...GIVING WAY TO A GRADUAL WARMING TREND ON FRI AND
SAT. MINIMUM RELATIVE HUMIDITY VALUES WILL BE IN THE UPPER TEENS OR
LOW 20S FOR WESTERN ZONES. AFTERNOON SHOWERS AND THUNDERSTORMS MAY
PRODUCE GUSTY AND ERRATIC WINDS THROUGH THE REST OF THE WEEK...BUT
IN GENERAL STRONG STORMS ARE NOT EXPECTED. A STRONG COLD FRONT WILL
MOVE FROM WEST TO EAST ACROSS THE AREA ON SAT AFTN...GIVING WAY TO
BREEZY CONDITIONS WITH WIND GUSTS UP TO 40 MPH OVER PARTS OF CARBON
COUNTY. COOLER TEMPERATURES WILL FOLLOW FOR SUN.

&&

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

$$

UPDATE...RUBIN
SHORT TERM...HAMMER
LONG TERM...HAHN
AVIATION...CLAYCOMB
FIRE WEATHER...HAMMER







000
FXUS65 KCYS 290044
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
644 PM MDT THU AUG 28 2014

.UPDATE...
ISSUED AT 640 PM MDT THU AUG 28 2014

GRIDDED FORECASTS AND ZONE FORECASTS HAVE BEEN UPDATED TO REMOVE
ALL MENTION OF PRECIPITATION FOR THE REST OF THE NIGHT BASED ON
WSR-88D RADAR LOOPS FROM CHEYENNE...DENVER...GRAND JUNCTION...
RIVERTON AND RAPID CITY. ALSO DECREASED CLOUD COVER BASED ON
VISIBLE AND INFRARED SATELLITE IMAGERY LOOPS. TEMPERATURES...
DEWPOINTS AND WINDS ALSO ADJUSTED FOR THE REST OF THE NIGHT BASED
ON CURRENT TRENDS.

&&

.SHORT TERM...(THIS EVENING THROUGH SATURDAY NIGHT)
ISSUED AT 313 PM MDT THU AUG 28 2014

LIGHT TO MODERATE RAIN HAS BEEN ONGOING FOR MUCH OF THE DAY ACROSS
SOUTHEAST WY AND THE WESTERN NE PANHANDLE. THIS IS OCCURRING ON THE
BACK SIDE OF A VIGOROUS MIDLVL SHORTWAVE CURRENTLY EXITING THE AREA
TO THE EAST OVER NE. WIDESPREAD CLOUDS/PCPN HAS WREAKED HAVOC ON THE
FCST TODAY WITH TEMPS ONLY IN THE 50S AT LAR AND CYS. AFTN RADAR AND
SATELLITE IMAGERY SHOWS THIS ACTIVITY HAS DECREASED IN COVERAGE AS
OF 20Z...AND BELIEVE THIS TREND SHOULD CONTINUE THROUGH THE EARLY
EVE HOURS AS BETTER UPPER-LEVEL SUPPORT SHIFTS TO THE EAST AND IS
REPLACED BY SUBSIDENCE BENEATH A SHORTWAVE RIDGE AXIS. VISIBLE SAT
INDICATES SKIES ARE CLEARING OVER OUR WESTERN ZONES...SO EXPECT A
QUIET OVERNIGHT PERIOD FOR THE MOST PART WITH MORE CLOUDS OVER THE
PANHANDLE. RAIN SHOULD END COMPLETELY BY 03-06Z FRI. WENT A LITTLE
WARMER FOR LOWS TONIGHT FARTHER EAST WHERE RADIATIONAL COOLING WILL
BE LESS.

WARMING TREND ENSUES FOR FRI WITH BROAD UPPER-LEVEL RIDGING IN PLACE
OVER THE CWA. ECMWF H7 TEMPS INCREASE TO 10-12 DEG C ON FRI...SO IT
SHOULD BE QUITE A BIT WARMER WITH DRY/SUBSIDING CONDITIONS IN PLACE
ACROSS THE AREA AND NO MAJOR INHIBITING FACTORS FOR SOME DECENT SFC
HEATING. A QUICK SHOT OF MIDLVL MOISTURE WITH A WEAK WAVE TRAVERSING
THE FLOW SHOULD PRODUCE ISOLATED SHOWERS AND STORMS...GENERALLY IN
THE AFTN. GFS INSTABILITY PARAMETERS ARE UNIMPRESSIVE WITH LIS ONLY
AROUND -1 TO -2C AND LESS THAN 500 J/KG SBCAPE. CONVECTION ON FRI
SHOULD BE GARDEN VARIETY. SAT WILL BE THE WARMEST DAY OF THE PERIOD
AHEAD OF A MORE SIGNIFICANT SHORTWAVE MOVING ACROSS THE PAC NW. MID
LEVEL LAPSE RATES AROUND 8-9 DEG C/KM SUGGEST BETTER INSTABILITY ON
SAT...BETTER OVER THE PANHANDLE WHERE SURFACE CAPES MAY APPROACH
1000 J/KG. INCREASED POPS FOR SAT AFTN AND EVE WITH EXCELLENT MODEL
AGREEMENT BETWEEN THE GFS/NAM/ECMWF WITH INCREASING 700-500 MILLIBAR
QG ASCENT. GOOD CONVERGENCE ALONG THE COLD FRONT WILL HELP GENERATE
CONVECTION AS WELL. COLD FRONT BLASTS ACROSS THE CWA ON SAT AFTN AND
EARLY EVE...ENHANCING PCPN CHANCES AND SETTING THE STAGE FOR A COOL
START TO THE EXTENDED PERIOD. IT WILL BE BREEZY AS WELL WITH 35 KTS
OF FLOW AT H7...ESPECIALLY ALONG AND WEST OF THE LARAMIE RANGE ON
SAT AFTN.

.LONG TERM...(SUNDAY THROUGH THURSDAY)
ISSUED AT 313 PM MDT THU AUG 28 2014

A RELATIVELY COOL AND UNSETTLED END OF THE WEEKEND EXPECTED AS AN
UPPER TROUGH AND ASSOCIATED SFC FRONT MOVES THRU. THE ECMWF IS
6-12 HOURS QUICKER WITH FROPA MOVING IT THRU AT THE END OF THE
PREVIOUS PERIOD. COMPARATIVELY...THE GFS HOLDS IT BACK UNTIL LATER
SUNDAY. IN EITHER CASE...EXPECT AT LEAST SOME CONVECTIVE
DEVELOPMENT SUNDAY...WITH BEST COVERAGE DURING THE LATE AFTERNOON
AND OVR THE NRN NEBRASKA PANHANDLE. TROUGH AXIS WILL CLEAR THE
AREA SUNDAY NIGHT AND WHEN COMBINED WITH NIGHTTIME STABILIZATION
WILL BRING AN END TO SHOWER/THUNDERSTORM CHANCES BY NIGHTFALL.
ANOTHER FAST MOVING SHORTWAVE WILL TRACK ACROSS THE AREA AGAIN ON
MONDAY. THERE MAY BE JUST ENOUGH MOISTURE/INSTABILITY TO INITIATE
AN ISOLATED SHOWER/STORM LATE MONDAY AFTERNOON OR EARLY MONDAY
EVENING EAST OF A CHADRON TO ALLIANCE LINE. A MUCH DRIER AIR MASS
WILL ADVECT IN TUE-THU ALLOWING A LLVL THERMAL RIDGE TO AMPLIFY.
THE RESULT WILL BE FOR DRY AND WARMER CONDITIONS. SUNDAY WILL BE
THE COOLEST DAY OF THE PERIOD IN THE COOL POST-FRONTAL AIR MASS.
PROGD H7 TEMPS ONLY REACH AROUND 8C...WHICH WILL KEEP AFTERNOON
TEMPS IN THE 60S AND 70S. H7 TEMPS WILL RETURN TO 12-16C FOR MON-
THU...BRINGING HIGH TEMPS BACK WELL INTO THE 70S WEST AND 80S TO
NR 90S EAST BY WED-THU.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z FRIDAY AFTERNOON)
ISSUED AT 455 PM MDT THU AUG 28 2014

LOW PRESSURE THAT BROUGHT THE WIDESPREAD RAIN IS MOVING OFF TO THE
EAST. STILL SOME SHOWERS FOR AN HOUR OR SO OUT IN THE PANHANDLE
THAT SHOULD END EARLY THIS EVENING. WESTERLY WINDS WILL BRING
DOWNSLOPING CONDITIONS FRIDAY...WHICH WILL GIVE THE AREA VFR
CONDITIONS.


&&

.FIRE WEATHER...
ISSUED AT 313 PM MDT THU AUG 28 2014

NO MAJOR FIRE WEATHER CONCERNS OVER THE NEXT FEW DAYS. THE WEATHER
SYSTEM RESPONSIBLE FOR THE RECENT RAINFALL WILL MOVE TO THE EAST OF
THE AREA TONIGHT...GIVING WAY TO A GRADUAL WARMING TREND ON FRI AND
SAT. MINIMUM RELATIVE HUMIDITY VALUES WILL BE IN THE UPPER TEENS OR
LOW 20S FOR WESTERN ZONES. AFTERNOON SHOWERS AND THUNDERSTORMS MAY
PRODUCE GUSTY AND ERRATIC WINDS THROUGH THE REST OF THE WEEK...BUT
IN GENERAL STRONG STORMS ARE NOT EXPECTED. A STRONG COLD FRONT WILL
MOVE FROM WEST TO EAST ACROSS THE AREA ON SAT AFTN...GIVING WAY TO
BREEZY CONDITIONS WITH WIND GUSTS UP TO 40 MPH OVER PARTS OF CARBON
COUNTY. COOLER TEMPERATURES WILL FOLLOW FOR SUN.

&&

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

$$

UPDATE...RUBIN
SHORT TERM...HAMMER
LONG TERM...HAHN
AVIATION...CLAYCOMB
FIRE WEATHER...HAMMER







000
FXUS65 KCYS 290044
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
644 PM MDT THU AUG 28 2014

.UPDATE...
ISSUED AT 640 PM MDT THU AUG 28 2014

GRIDDED FORECASTS AND ZONE FORECASTS HAVE BEEN UPDATED TO REMOVE
ALL MENTION OF PRECIPITATION FOR THE REST OF THE NIGHT BASED ON
WSR-88D RADAR LOOPS FROM CHEYENNE...DENVER...GRAND JUNCTION...
RIVERTON AND RAPID CITY. ALSO DECREASED CLOUD COVER BASED ON
VISIBLE AND INFRARED SATELLITE IMAGERY LOOPS. TEMPERATURES...
DEWPOINTS AND WINDS ALSO ADJUSTED FOR THE REST OF THE NIGHT BASED
ON CURRENT TRENDS.

&&

.SHORT TERM...(THIS EVENING THROUGH SATURDAY NIGHT)
ISSUED AT 313 PM MDT THU AUG 28 2014

LIGHT TO MODERATE RAIN HAS BEEN ONGOING FOR MUCH OF THE DAY ACROSS
SOUTHEAST WY AND THE WESTERN NE PANHANDLE. THIS IS OCCURRING ON THE
BACK SIDE OF A VIGOROUS MIDLVL SHORTWAVE CURRENTLY EXITING THE AREA
TO THE EAST OVER NE. WIDESPREAD CLOUDS/PCPN HAS WREAKED HAVOC ON THE
FCST TODAY WITH TEMPS ONLY IN THE 50S AT LAR AND CYS. AFTN RADAR AND
SATELLITE IMAGERY SHOWS THIS ACTIVITY HAS DECREASED IN COVERAGE AS
OF 20Z...AND BELIEVE THIS TREND SHOULD CONTINUE THROUGH THE EARLY
EVE HOURS AS BETTER UPPER-LEVEL SUPPORT SHIFTS TO THE EAST AND IS
REPLACED BY SUBSIDENCE BENEATH A SHORTWAVE RIDGE AXIS. VISIBLE SAT
INDICATES SKIES ARE CLEARING OVER OUR WESTERN ZONES...SO EXPECT A
QUIET OVERNIGHT PERIOD FOR THE MOST PART WITH MORE CLOUDS OVER THE
PANHANDLE. RAIN SHOULD END COMPLETELY BY 03-06Z FRI. WENT A LITTLE
WARMER FOR LOWS TONIGHT FARTHER EAST WHERE RADIATIONAL COOLING WILL
BE LESS.

WARMING TREND ENSUES FOR FRI WITH BROAD UPPER-LEVEL RIDGING IN PLACE
OVER THE CWA. ECMWF H7 TEMPS INCREASE TO 10-12 DEG C ON FRI...SO IT
SHOULD BE QUITE A BIT WARMER WITH DRY/SUBSIDING CONDITIONS IN PLACE
ACROSS THE AREA AND NO MAJOR INHIBITING FACTORS FOR SOME DECENT SFC
HEATING. A QUICK SHOT OF MIDLVL MOISTURE WITH A WEAK WAVE TRAVERSING
THE FLOW SHOULD PRODUCE ISOLATED SHOWERS AND STORMS...GENERALLY IN
THE AFTN. GFS INSTABILITY PARAMETERS ARE UNIMPRESSIVE WITH LIS ONLY
AROUND -1 TO -2C AND LESS THAN 500 J/KG SBCAPE. CONVECTION ON FRI
SHOULD BE GARDEN VARIETY. SAT WILL BE THE WARMEST DAY OF THE PERIOD
AHEAD OF A MORE SIGNIFICANT SHORTWAVE MOVING ACROSS THE PAC NW. MID
LEVEL LAPSE RATES AROUND 8-9 DEG C/KM SUGGEST BETTER INSTABILITY ON
SAT...BETTER OVER THE PANHANDLE WHERE SURFACE CAPES MAY APPROACH
1000 J/KG. INCREASED POPS FOR SAT AFTN AND EVE WITH EXCELLENT MODEL
AGREEMENT BETWEEN THE GFS/NAM/ECMWF WITH INCREASING 700-500 MILLIBAR
QG ASCENT. GOOD CONVERGENCE ALONG THE COLD FRONT WILL HELP GENERATE
CONVECTION AS WELL. COLD FRONT BLASTS ACROSS THE CWA ON SAT AFTN AND
EARLY EVE...ENHANCING PCPN CHANCES AND SETTING THE STAGE FOR A COOL
START TO THE EXTENDED PERIOD. IT WILL BE BREEZY AS WELL WITH 35 KTS
OF FLOW AT H7...ESPECIALLY ALONG AND WEST OF THE LARAMIE RANGE ON
SAT AFTN.

.LONG TERM...(SUNDAY THROUGH THURSDAY)
ISSUED AT 313 PM MDT THU AUG 28 2014

A RELATIVELY COOL AND UNSETTLED END OF THE WEEKEND EXPECTED AS AN
UPPER TROUGH AND ASSOCIATED SFC FRONT MOVES THRU. THE ECMWF IS
6-12 HOURS QUICKER WITH FROPA MOVING IT THRU AT THE END OF THE
PREVIOUS PERIOD. COMPARATIVELY...THE GFS HOLDS IT BACK UNTIL LATER
SUNDAY. IN EITHER CASE...EXPECT AT LEAST SOME CONVECTIVE
DEVELOPMENT SUNDAY...WITH BEST COVERAGE DURING THE LATE AFTERNOON
AND OVR THE NRN NEBRASKA PANHANDLE. TROUGH AXIS WILL CLEAR THE
AREA SUNDAY NIGHT AND WHEN COMBINED WITH NIGHTTIME STABILIZATION
WILL BRING AN END TO SHOWER/THUNDERSTORM CHANCES BY NIGHTFALL.
ANOTHER FAST MOVING SHORTWAVE WILL TRACK ACROSS THE AREA AGAIN ON
MONDAY. THERE MAY BE JUST ENOUGH MOISTURE/INSTABILITY TO INITIATE
AN ISOLATED SHOWER/STORM LATE MONDAY AFTERNOON OR EARLY MONDAY
EVENING EAST OF A CHADRON TO ALLIANCE LINE. A MUCH DRIER AIR MASS
WILL ADVECT IN TUE-THU ALLOWING A LLVL THERMAL RIDGE TO AMPLIFY.
THE RESULT WILL BE FOR DRY AND WARMER CONDITIONS. SUNDAY WILL BE
THE COOLEST DAY OF THE PERIOD IN THE COOL POST-FRONTAL AIR MASS.
PROGD H7 TEMPS ONLY REACH AROUND 8C...WHICH WILL KEEP AFTERNOON
TEMPS IN THE 60S AND 70S. H7 TEMPS WILL RETURN TO 12-16C FOR MON-
THU...BRINGING HIGH TEMPS BACK WELL INTO THE 70S WEST AND 80S TO
NR 90S EAST BY WED-THU.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z FRIDAY AFTERNOON)
ISSUED AT 455 PM MDT THU AUG 28 2014

LOW PRESSURE THAT BROUGHT THE WIDESPREAD RAIN IS MOVING OFF TO THE
EAST. STILL SOME SHOWERS FOR AN HOUR OR SO OUT IN THE PANHANDLE
THAT SHOULD END EARLY THIS EVENING. WESTERLY WINDS WILL BRING
DOWNSLOPING CONDITIONS FRIDAY...WHICH WILL GIVE THE AREA VFR
CONDITIONS.


&&

.FIRE WEATHER...
ISSUED AT 313 PM MDT THU AUG 28 2014

NO MAJOR FIRE WEATHER CONCERNS OVER THE NEXT FEW DAYS. THE WEATHER
SYSTEM RESPONSIBLE FOR THE RECENT RAINFALL WILL MOVE TO THE EAST OF
THE AREA TONIGHT...GIVING WAY TO A GRADUAL WARMING TREND ON FRI AND
SAT. MINIMUM RELATIVE HUMIDITY VALUES WILL BE IN THE UPPER TEENS OR
LOW 20S FOR WESTERN ZONES. AFTERNOON SHOWERS AND THUNDERSTORMS MAY
PRODUCE GUSTY AND ERRATIC WINDS THROUGH THE REST OF THE WEEK...BUT
IN GENERAL STRONG STORMS ARE NOT EXPECTED. A STRONG COLD FRONT WILL
MOVE FROM WEST TO EAST ACROSS THE AREA ON SAT AFTN...GIVING WAY TO
BREEZY CONDITIONS WITH WIND GUSTS UP TO 40 MPH OVER PARTS OF CARBON
COUNTY. COOLER TEMPERATURES WILL FOLLOW FOR SUN.

&&

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

$$

UPDATE...RUBIN
SHORT TERM...HAMMER
LONG TERM...HAHN
AVIATION...CLAYCOMB
FIRE WEATHER...HAMMER






000
FXUS63 KUNR 282323
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
523 PM MDT THU AUG 28 2014

.SHORT TERM...THIS EVENING THROUGH FRIDAY NIGHT
ISSUED AT 330 PM MDT THU AUG 28 2014

CURRENT SURFACE ANALYSIS SHOWS LOW PRESSURE OVER CENTRAL
NEB...WITH INVERTED TROF STRETCHING NORTHWARD ACROSS CENTRAL SD.
HIGH PRESSURE IS IN PLACE OVER THE CENTRAL ROCKIES. UPPER LEVEL
ANALYSIS SHOWS LOW NOW OVER FAR NORTHEAST CO...SLOWLY MOVING EAST-
SOUTHEAST. KUDX RADAR SHOWS ISOLATED TO SCATTERED SHOWERS FROM
CENTRAL SD TO FAR SOUTHWEST SD. THERE ARE A FEW LIGHTNING STRIKES
FROM TIME TO TIME WITH THE ACTIVITY OVER SOUTHERN SD. SKIES RANGE
FROM MOSTLY SUNNY OVER NORTHEAST WY AND FAR NORTHWEST SD TO MOSTLY
CLOUDY SOUTH AND EAST OF THE BLACK HILLS. TEMPS ARE IN THE 70S AND
LOWER 80S WITH LIGHT NORTHERLY WINDS IN MOST AREAS.

CONDITIONS WILL CONTINUE TO GRADUALLY IMPROVE THROUGH THE EVENING
FOR AREAS SOUTH AND EAST OF THE BLACK HILLS...WITH MOSTLY CLEAR
SKIES OVER WESTERN AND NORTHERN AREAS. HAVE ADDED CHANCES FOR
SHOWERS AND STORMS ACROSS SOUTH CENTRAL SD FOR THE EVENING HOURS AS
SYSTEM IS SLOWER TO MOVE OUT THAN WAS EXPECTED. WITH LOW LEVEL
MOISTURE HANGING AROUND OVER EASTERN PORTIONS OF THE CWA...HAVE KEPT
PATCHY FOG IN FOR MOST OF THE SD PLAINS. LOWS TONIGHT WILL BE IN THE
50S AND LOWER 60S. WINDS WILL MOSTLY BE LIGHT AND VARIABLE.

THE NEXT UPPER LEVEL WAVE...MUCH WEAKER THAN THE CURRENT ONE...WILL
MOVE QUICKLY INTO THE AREA ON FRIDAY...WITH INCREASING CHANCES FOR
SHOWERS AND THUNDERSTORMS THROUGH THE DAY FROM WEST TO EAST. A WEAK
COLD FRONT WILL ALSO SLIDE SOUTH INTO THE AREA WITH THE SHORTWAVE.
THE THREAT FOR SEVERE STORMS WILL REMAIN VERY LOW...BUT SUFFICIENT
INSTABILITY IS EXPECTED TO THE EAST OF THE BLACK HILLS IN THE
AFTERNOON TO POSSIBLY GET A STRONG STORM OR TWO GOING. HIGHS WILL BE
IN THE 80S...WITH SOME 70S ACROSS THE BLACK HILLS AND FAR
NORTHWESTERN SD. NORTHWESTERLY WINDS WILL INCREASE BEHIND THE FRONT
DURING THE LATE MORNING AND AFTERNOON...A BIT BREEZY AT TIMES OVER
THE WESTERN SD PLAINS. LINGERING SHOWERS SHOULD TAPER OFF QUICKLY IN
THE EVENING AS THE WAVE PUSHES EAST OF THE AREA.

&&

.LONG TERM...SATURDAY THROUGH THURSDAY
ISSUED AT 330 PM MDT THU AUG 28 2014

SATURDAY...SHORTWAVE RIDGE OVER THE CWA WILL QUICKLY MOVE INTO THE
MIDWEST DURING THE DAY AS A SHORTWAVE TROUGH ZIPS THROUGH MT INTO
ND/WY BY SATURDAY EVENING. SURFACE CYCLONE WILL DEVELOP OVER EASTERN
MT AND MOVES INTO THE CENTRAL DAKOTAS SATURDAY NIGHT. LOW LEVEL
MOISTURE CONVERGENCE ALONG THE FRONT WILL RESULT IN A NARROW BAND OF
1-2KJ/KG MLCAPE FROM SOUTHEAST MT INTO CENTRAL SD. 15-20M/S 0-6KM
BULK SHEAR SPREADS ACROSS NORTHWEST SD DURING PEAK HEATING. MLCIN
SHOULD BE BROKEN BY SURFACE FORCING AND LIFT AHEAD OF SHORTWAVE
RESULTING IN STRONG/POTENTIALLY SEVERE THUNDERSTORMS LATER SATURDAY
AFTERNOON INTO THE EVENING HOURS. STORMS MAY CONGEAL INTO A SMALL
MCS GIVEN DEVELOPING 50KT LOW LEVEL JET ACROSS THE EASTERN DAKOTAS
SATURDAY NIGHT. TEMPERATURES WILL BE TRICKY WITH VERY WARM READINGS
AHEAD OF THE LOW AND COOLER READINGS BEHIND THE FRONT.

SUNDAY THROUGH TUESDAY...UPPER TROUGH WITH EMBEDDED SHORTWAVES
SAUNTERS ACROSS THE DAKOTAS/SOUTH CENTRAL CANADA BRINGING SHRA/TSRA
CHANCES...ALTHOUGH COVERAGE SHOULD BE LOWER THAN RECENT MEMORY GIVEN
DRIER NORTHWEST FLOW. TEMPERATURES WILL BE NOTICEABLY COOLER SUNDAY
AND THEN WARM SLIGHTLY THROUGH TUESDAY.

WEDNESDAY/THURSDAY...UPPER RIDGE SHOULD BUILD INTO THE NORTHERN
PLAINS AS UPPER TROUGH DEEPENS OVER THE NORTHWEST US. DRIER AND
WARMER PATTERN MAY EVOLVE GIVEN THERMAL RIDGE AMPLIFICATION.

&&

.AVIATION...FOR THE 00Z TAFS THROUGH 00Z FRIDAY EVENING
ISSUED AT 520 PM MDT THU AUG 28 2014

SCATTERED -SHRA ALONG/EAST OF A LINE FROM KMGB TO KCDR WILL
CONTINUE TO SLIDE EAST THIS EVENING...EXITING THE AREA COMPLETELY
LATER THIS EVENING. AREAS OF MVFR CIGS ASSOCIATED WITH THE
PRECIPITATION WILL SHIFT EAST ALSO. BEHIND THESE FEATURES...VFR
CONDITIONS ARE EXPECTED THROUGH FRIDAY MORNING. THE EXCEPTION WILL
BE ON THE SD PLAINS LATER TONIGHT WHERE LOCAL MVFR VSBYS DUE TO
FOG MAY OCCUR.

&&

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

$$

SHORT TERM...26
LONG TERM...HELGESON
AVIATION...10






000
FXUS63 KUNR 282323
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
523 PM MDT THU AUG 28 2014

.SHORT TERM...THIS EVENING THROUGH FRIDAY NIGHT
ISSUED AT 330 PM MDT THU AUG 28 2014

CURRENT SURFACE ANALYSIS SHOWS LOW PRESSURE OVER CENTRAL
NEB...WITH INVERTED TROF STRETCHING NORTHWARD ACROSS CENTRAL SD.
HIGH PRESSURE IS IN PLACE OVER THE CENTRAL ROCKIES. UPPER LEVEL
ANALYSIS SHOWS LOW NOW OVER FAR NORTHEAST CO...SLOWLY MOVING EAST-
SOUTHEAST. KUDX RADAR SHOWS ISOLATED TO SCATTERED SHOWERS FROM
CENTRAL SD TO FAR SOUTHWEST SD. THERE ARE A FEW LIGHTNING STRIKES
FROM TIME TO TIME WITH THE ACTIVITY OVER SOUTHERN SD. SKIES RANGE
FROM MOSTLY SUNNY OVER NORTHEAST WY AND FAR NORTHWEST SD TO MOSTLY
CLOUDY SOUTH AND EAST OF THE BLACK HILLS. TEMPS ARE IN THE 70S AND
LOWER 80S WITH LIGHT NORTHERLY WINDS IN MOST AREAS.

CONDITIONS WILL CONTINUE TO GRADUALLY IMPROVE THROUGH THE EVENING
FOR AREAS SOUTH AND EAST OF THE BLACK HILLS...WITH MOSTLY CLEAR
SKIES OVER WESTERN AND NORTHERN AREAS. HAVE ADDED CHANCES FOR
SHOWERS AND STORMS ACROSS SOUTH CENTRAL SD FOR THE EVENING HOURS AS
SYSTEM IS SLOWER TO MOVE OUT THAN WAS EXPECTED. WITH LOW LEVEL
MOISTURE HANGING AROUND OVER EASTERN PORTIONS OF THE CWA...HAVE KEPT
PATCHY FOG IN FOR MOST OF THE SD PLAINS. LOWS TONIGHT WILL BE IN THE
50S AND LOWER 60S. WINDS WILL MOSTLY BE LIGHT AND VARIABLE.

THE NEXT UPPER LEVEL WAVE...MUCH WEAKER THAN THE CURRENT ONE...WILL
MOVE QUICKLY INTO THE AREA ON FRIDAY...WITH INCREASING CHANCES FOR
SHOWERS AND THUNDERSTORMS THROUGH THE DAY FROM WEST TO EAST. A WEAK
COLD FRONT WILL ALSO SLIDE SOUTH INTO THE AREA WITH THE SHORTWAVE.
THE THREAT FOR SEVERE STORMS WILL REMAIN VERY LOW...BUT SUFFICIENT
INSTABILITY IS EXPECTED TO THE EAST OF THE BLACK HILLS IN THE
AFTERNOON TO POSSIBLY GET A STRONG STORM OR TWO GOING. HIGHS WILL BE
IN THE 80S...WITH SOME 70S ACROSS THE BLACK HILLS AND FAR
NORTHWESTERN SD. NORTHWESTERLY WINDS WILL INCREASE BEHIND THE FRONT
DURING THE LATE MORNING AND AFTERNOON...A BIT BREEZY AT TIMES OVER
THE WESTERN SD PLAINS. LINGERING SHOWERS SHOULD TAPER OFF QUICKLY IN
THE EVENING AS THE WAVE PUSHES EAST OF THE AREA.

&&

.LONG TERM...SATURDAY THROUGH THURSDAY
ISSUED AT 330 PM MDT THU AUG 28 2014

SATURDAY...SHORTWAVE RIDGE OVER THE CWA WILL QUICKLY MOVE INTO THE
MIDWEST DURING THE DAY AS A SHORTWAVE TROUGH ZIPS THROUGH MT INTO
ND/WY BY SATURDAY EVENING. SURFACE CYCLONE WILL DEVELOP OVER EASTERN
MT AND MOVES INTO THE CENTRAL DAKOTAS SATURDAY NIGHT. LOW LEVEL
MOISTURE CONVERGENCE ALONG THE FRONT WILL RESULT IN A NARROW BAND OF
1-2KJ/KG MLCAPE FROM SOUTHEAST MT INTO CENTRAL SD. 15-20M/S 0-6KM
BULK SHEAR SPREADS ACROSS NORTHWEST SD DURING PEAK HEATING. MLCIN
SHOULD BE BROKEN BY SURFACE FORCING AND LIFT AHEAD OF SHORTWAVE
RESULTING IN STRONG/POTENTIALLY SEVERE THUNDERSTORMS LATER SATURDAY
AFTERNOON INTO THE EVENING HOURS. STORMS MAY CONGEAL INTO A SMALL
MCS GIVEN DEVELOPING 50KT LOW LEVEL JET ACROSS THE EASTERN DAKOTAS
SATURDAY NIGHT. TEMPERATURES WILL BE TRICKY WITH VERY WARM READINGS
AHEAD OF THE LOW AND COOLER READINGS BEHIND THE FRONT.

SUNDAY THROUGH TUESDAY...UPPER TROUGH WITH EMBEDDED SHORTWAVES
SAUNTERS ACROSS THE DAKOTAS/SOUTH CENTRAL CANADA BRINGING SHRA/TSRA
CHANCES...ALTHOUGH COVERAGE SHOULD BE LOWER THAN RECENT MEMORY GIVEN
DRIER NORTHWEST FLOW. TEMPERATURES WILL BE NOTICEABLY COOLER SUNDAY
AND THEN WARM SLIGHTLY THROUGH TUESDAY.

WEDNESDAY/THURSDAY...UPPER RIDGE SHOULD BUILD INTO THE NORTHERN
PLAINS AS UPPER TROUGH DEEPENS OVER THE NORTHWEST US. DRIER AND
WARMER PATTERN MAY EVOLVE GIVEN THERMAL RIDGE AMPLIFICATION.

&&

.AVIATION...FOR THE 00Z TAFS THROUGH 00Z FRIDAY EVENING
ISSUED AT 520 PM MDT THU AUG 28 2014

SCATTERED -SHRA ALONG/EAST OF A LINE FROM KMGB TO KCDR WILL
CONTINUE TO SLIDE EAST THIS EVENING...EXITING THE AREA COMPLETELY
LATER THIS EVENING. AREAS OF MVFR CIGS ASSOCIATED WITH THE
PRECIPITATION WILL SHIFT EAST ALSO. BEHIND THESE FEATURES...VFR
CONDITIONS ARE EXPECTED THROUGH FRIDAY MORNING. THE EXCEPTION WILL
BE ON THE SD PLAINS LATER TONIGHT WHERE LOCAL MVFR VSBYS DUE TO
FOG MAY OCCUR.

&&

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

$$

SHORT TERM...26
LONG TERM...HELGESON
AVIATION...10






000
FXUS63 KUNR 282323
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
523 PM MDT THU AUG 28 2014

.SHORT TERM...THIS EVENING THROUGH FRIDAY NIGHT
ISSUED AT 330 PM MDT THU AUG 28 2014

CURRENT SURFACE ANALYSIS SHOWS LOW PRESSURE OVER CENTRAL
NEB...WITH INVERTED TROF STRETCHING NORTHWARD ACROSS CENTRAL SD.
HIGH PRESSURE IS IN PLACE OVER THE CENTRAL ROCKIES. UPPER LEVEL
ANALYSIS SHOWS LOW NOW OVER FAR NORTHEAST CO...SLOWLY MOVING EAST-
SOUTHEAST. KUDX RADAR SHOWS ISOLATED TO SCATTERED SHOWERS FROM
CENTRAL SD TO FAR SOUTHWEST SD. THERE ARE A FEW LIGHTNING STRIKES
FROM TIME TO TIME WITH THE ACTIVITY OVER SOUTHERN SD. SKIES RANGE
FROM MOSTLY SUNNY OVER NORTHEAST WY AND FAR NORTHWEST SD TO MOSTLY
CLOUDY SOUTH AND EAST OF THE BLACK HILLS. TEMPS ARE IN THE 70S AND
LOWER 80S WITH LIGHT NORTHERLY WINDS IN MOST AREAS.

CONDITIONS WILL CONTINUE TO GRADUALLY IMPROVE THROUGH THE EVENING
FOR AREAS SOUTH AND EAST OF THE BLACK HILLS...WITH MOSTLY CLEAR
SKIES OVER WESTERN AND NORTHERN AREAS. HAVE ADDED CHANCES FOR
SHOWERS AND STORMS ACROSS SOUTH CENTRAL SD FOR THE EVENING HOURS AS
SYSTEM IS SLOWER TO MOVE OUT THAN WAS EXPECTED. WITH LOW LEVEL
MOISTURE HANGING AROUND OVER EASTERN PORTIONS OF THE CWA...HAVE KEPT
PATCHY FOG IN FOR MOST OF THE SD PLAINS. LOWS TONIGHT WILL BE IN THE
50S AND LOWER 60S. WINDS WILL MOSTLY BE LIGHT AND VARIABLE.

THE NEXT UPPER LEVEL WAVE...MUCH WEAKER THAN THE CURRENT ONE...WILL
MOVE QUICKLY INTO THE AREA ON FRIDAY...WITH INCREASING CHANCES FOR
SHOWERS AND THUNDERSTORMS THROUGH THE DAY FROM WEST TO EAST. A WEAK
COLD FRONT WILL ALSO SLIDE SOUTH INTO THE AREA WITH THE SHORTWAVE.
THE THREAT FOR SEVERE STORMS WILL REMAIN VERY LOW...BUT SUFFICIENT
INSTABILITY IS EXPECTED TO THE EAST OF THE BLACK HILLS IN THE
AFTERNOON TO POSSIBLY GET A STRONG STORM OR TWO GOING. HIGHS WILL BE
IN THE 80S...WITH SOME 70S ACROSS THE BLACK HILLS AND FAR
NORTHWESTERN SD. NORTHWESTERLY WINDS WILL INCREASE BEHIND THE FRONT
DURING THE LATE MORNING AND AFTERNOON...A BIT BREEZY AT TIMES OVER
THE WESTERN SD PLAINS. LINGERING SHOWERS SHOULD TAPER OFF QUICKLY IN
THE EVENING AS THE WAVE PUSHES EAST OF THE AREA.

&&

.LONG TERM...SATURDAY THROUGH THURSDAY
ISSUED AT 330 PM MDT THU AUG 28 2014

SATURDAY...SHORTWAVE RIDGE OVER THE CWA WILL QUICKLY MOVE INTO THE
MIDWEST DURING THE DAY AS A SHORTWAVE TROUGH ZIPS THROUGH MT INTO
ND/WY BY SATURDAY EVENING. SURFACE CYCLONE WILL DEVELOP OVER EASTERN
MT AND MOVES INTO THE CENTRAL DAKOTAS SATURDAY NIGHT. LOW LEVEL
MOISTURE CONVERGENCE ALONG THE FRONT WILL RESULT IN A NARROW BAND OF
1-2KJ/KG MLCAPE FROM SOUTHEAST MT INTO CENTRAL SD. 15-20M/S 0-6KM
BULK SHEAR SPREADS ACROSS NORTHWEST SD DURING PEAK HEATING. MLCIN
SHOULD BE BROKEN BY SURFACE FORCING AND LIFT AHEAD OF SHORTWAVE
RESULTING IN STRONG/POTENTIALLY SEVERE THUNDERSTORMS LATER SATURDAY
AFTERNOON INTO THE EVENING HOURS. STORMS MAY CONGEAL INTO A SMALL
MCS GIVEN DEVELOPING 50KT LOW LEVEL JET ACROSS THE EASTERN DAKOTAS
SATURDAY NIGHT. TEMPERATURES WILL BE TRICKY WITH VERY WARM READINGS
AHEAD OF THE LOW AND COOLER READINGS BEHIND THE FRONT.

SUNDAY THROUGH TUESDAY...UPPER TROUGH WITH EMBEDDED SHORTWAVES
SAUNTERS ACROSS THE DAKOTAS/SOUTH CENTRAL CANADA BRINGING SHRA/TSRA
CHANCES...ALTHOUGH COVERAGE SHOULD BE LOWER THAN RECENT MEMORY GIVEN
DRIER NORTHWEST FLOW. TEMPERATURES WILL BE NOTICEABLY COOLER SUNDAY
AND THEN WARM SLIGHTLY THROUGH TUESDAY.

WEDNESDAY/THURSDAY...UPPER RIDGE SHOULD BUILD INTO THE NORTHERN
PLAINS AS UPPER TROUGH DEEPENS OVER THE NORTHWEST US. DRIER AND
WARMER PATTERN MAY EVOLVE GIVEN THERMAL RIDGE AMPLIFICATION.

&&

.AVIATION...FOR THE 00Z TAFS THROUGH 00Z FRIDAY EVENING
ISSUED AT 520 PM MDT THU AUG 28 2014

SCATTERED -SHRA ALONG/EAST OF A LINE FROM KMGB TO KCDR WILL
CONTINUE TO SLIDE EAST THIS EVENING...EXITING THE AREA COMPLETELY
LATER THIS EVENING. AREAS OF MVFR CIGS ASSOCIATED WITH THE
PRECIPITATION WILL SHIFT EAST ALSO. BEHIND THESE FEATURES...VFR
CONDITIONS ARE EXPECTED THROUGH FRIDAY MORNING. THE EXCEPTION WILL
BE ON THE SD PLAINS LATER TONIGHT WHERE LOCAL MVFR VSBYS DUE TO
FOG MAY OCCUR.

&&

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

$$

SHORT TERM...26
LONG TERM...HELGESON
AVIATION...10






000
FXUS63 KUNR 282323
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
523 PM MDT THU AUG 28 2014

.SHORT TERM...THIS EVENING THROUGH FRIDAY NIGHT
ISSUED AT 330 PM MDT THU AUG 28 2014

CURRENT SURFACE ANALYSIS SHOWS LOW PRESSURE OVER CENTRAL
NEB...WITH INVERTED TROF STRETCHING NORTHWARD ACROSS CENTRAL SD.
HIGH PRESSURE IS IN PLACE OVER THE CENTRAL ROCKIES. UPPER LEVEL
ANALYSIS SHOWS LOW NOW OVER FAR NORTHEAST CO...SLOWLY MOVING EAST-
SOUTHEAST. KUDX RADAR SHOWS ISOLATED TO SCATTERED SHOWERS FROM
CENTRAL SD TO FAR SOUTHWEST SD. THERE ARE A FEW LIGHTNING STRIKES
FROM TIME TO TIME WITH THE ACTIVITY OVER SOUTHERN SD. SKIES RANGE
FROM MOSTLY SUNNY OVER NORTHEAST WY AND FAR NORTHWEST SD TO MOSTLY
CLOUDY SOUTH AND EAST OF THE BLACK HILLS. TEMPS ARE IN THE 70S AND
LOWER 80S WITH LIGHT NORTHERLY WINDS IN MOST AREAS.

CONDITIONS WILL CONTINUE TO GRADUALLY IMPROVE THROUGH THE EVENING
FOR AREAS SOUTH AND EAST OF THE BLACK HILLS...WITH MOSTLY CLEAR
SKIES OVER WESTERN AND NORTHERN AREAS. HAVE ADDED CHANCES FOR
SHOWERS AND STORMS ACROSS SOUTH CENTRAL SD FOR THE EVENING HOURS AS
SYSTEM IS SLOWER TO MOVE OUT THAN WAS EXPECTED. WITH LOW LEVEL
MOISTURE HANGING AROUND OVER EASTERN PORTIONS OF THE CWA...HAVE KEPT
PATCHY FOG IN FOR MOST OF THE SD PLAINS. LOWS TONIGHT WILL BE IN THE
50S AND LOWER 60S. WINDS WILL MOSTLY BE LIGHT AND VARIABLE.

THE NEXT UPPER LEVEL WAVE...MUCH WEAKER THAN THE CURRENT ONE...WILL
MOVE QUICKLY INTO THE AREA ON FRIDAY...WITH INCREASING CHANCES FOR
SHOWERS AND THUNDERSTORMS THROUGH THE DAY FROM WEST TO EAST. A WEAK
COLD FRONT WILL ALSO SLIDE SOUTH INTO THE AREA WITH THE SHORTWAVE.
THE THREAT FOR SEVERE STORMS WILL REMAIN VERY LOW...BUT SUFFICIENT
INSTABILITY IS EXPECTED TO THE EAST OF THE BLACK HILLS IN THE
AFTERNOON TO POSSIBLY GET A STRONG STORM OR TWO GOING. HIGHS WILL BE
IN THE 80S...WITH SOME 70S ACROSS THE BLACK HILLS AND FAR
NORTHWESTERN SD. NORTHWESTERLY WINDS WILL INCREASE BEHIND THE FRONT
DURING THE LATE MORNING AND AFTERNOON...A BIT BREEZY AT TIMES OVER
THE WESTERN SD PLAINS. LINGERING SHOWERS SHOULD TAPER OFF QUICKLY IN
THE EVENING AS THE WAVE PUSHES EAST OF THE AREA.

&&

.LONG TERM...SATURDAY THROUGH THURSDAY
ISSUED AT 330 PM MDT THU AUG 28 2014

SATURDAY...SHORTWAVE RIDGE OVER THE CWA WILL QUICKLY MOVE INTO THE
MIDWEST DURING THE DAY AS A SHORTWAVE TROUGH ZIPS THROUGH MT INTO
ND/WY BY SATURDAY EVENING. SURFACE CYCLONE WILL DEVELOP OVER EASTERN
MT AND MOVES INTO THE CENTRAL DAKOTAS SATURDAY NIGHT. LOW LEVEL
MOISTURE CONVERGENCE ALONG THE FRONT WILL RESULT IN A NARROW BAND OF
1-2KJ/KG MLCAPE FROM SOUTHEAST MT INTO CENTRAL SD. 15-20M/S 0-6KM
BULK SHEAR SPREADS ACROSS NORTHWEST SD DURING PEAK HEATING. MLCIN
SHOULD BE BROKEN BY SURFACE FORCING AND LIFT AHEAD OF SHORTWAVE
RESULTING IN STRONG/POTENTIALLY SEVERE THUNDERSTORMS LATER SATURDAY
AFTERNOON INTO THE EVENING HOURS. STORMS MAY CONGEAL INTO A SMALL
MCS GIVEN DEVELOPING 50KT LOW LEVEL JET ACROSS THE EASTERN DAKOTAS
SATURDAY NIGHT. TEMPERATURES WILL BE TRICKY WITH VERY WARM READINGS
AHEAD OF THE LOW AND COOLER READINGS BEHIND THE FRONT.

SUNDAY THROUGH TUESDAY...UPPER TROUGH WITH EMBEDDED SHORTWAVES
SAUNTERS ACROSS THE DAKOTAS/SOUTH CENTRAL CANADA BRINGING SHRA/TSRA
CHANCES...ALTHOUGH COVERAGE SHOULD BE LOWER THAN RECENT MEMORY GIVEN
DRIER NORTHWEST FLOW. TEMPERATURES WILL BE NOTICEABLY COOLER SUNDAY
AND THEN WARM SLIGHTLY THROUGH TUESDAY.

WEDNESDAY/THURSDAY...UPPER RIDGE SHOULD BUILD INTO THE NORTHERN
PLAINS AS UPPER TROUGH DEEPENS OVER THE NORTHWEST US. DRIER AND
WARMER PATTERN MAY EVOLVE GIVEN THERMAL RIDGE AMPLIFICATION.

&&

.AVIATION...FOR THE 00Z TAFS THROUGH 00Z FRIDAY EVENING
ISSUED AT 520 PM MDT THU AUG 28 2014

SCATTERED -SHRA ALONG/EAST OF A LINE FROM KMGB TO KCDR WILL
CONTINUE TO SLIDE EAST THIS EVENING...EXITING THE AREA COMPLETELY
LATER THIS EVENING. AREAS OF MVFR CIGS ASSOCIATED WITH THE
PRECIPITATION WILL SHIFT EAST ALSO. BEHIND THESE FEATURES...VFR
CONDITIONS ARE EXPECTED THROUGH FRIDAY MORNING. THE EXCEPTION WILL
BE ON THE SD PLAINS LATER TONIGHT WHERE LOCAL MVFR VSBYS DUE TO
FOG MAY OCCUR.

&&

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

$$

SHORT TERM...26
LONG TERM...HELGESON
AVIATION...10






000
FXUS65 KCYS 282258
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
458 PM MDT THU AUG 28 2014

.SHORT TERM...(THIS EVENING THROUGH SATURDAY NIGHT)
ISSUED AT 313 PM MDT THU AUG 28 2014

LIGHT TO MODERATE RAIN HAS BEEN ONGOING FOR MUCH OF THE DAY ACROSS
SOUTHEAST WY AND THE WESTERN NE PANHANDLE. THIS IS OCCURRING ON THE
BACK SIDE OF A VIGOROUS MIDLVL SHORTWAVE CURRENTLY EXITING THE AREA
TO THE EAST OVER NE. WIDESPREAD CLOUDS/PCPN HAS WREAKED HAVOC ON THE
FCST TODAY WITH TEMPS ONLY IN THE 50S AT LAR AND CYS. AFTN RADAR AND
SATELLITE IMAGERY SHOWS THIS ACTIVITY HAS DECREASED IN COVERAGE AS
OF 20Z...AND BELIEVE THIS TREND SHOULD CONTINUE THROUGH THE EARLY
EVE HOURS AS BETTER UPPER-LEVEL SUPPORT SHIFTS TO THE EAST AND IS
REPLACED BY SUBSIDENCE BENEATH A SHORTWAVE RIDGE AXIS. VISIBLE SAT
INDICATES SKIES ARE CLEARING OVER OUR WESTERN ZONES...SO EXPECT A
QUIET OVERNIGHT PERIOD FOR THE MOST PART WITH MORE CLOUDS OVER THE
PANHANDLE. RAIN SHOULD END COMPLETELY BY 03-06Z FRI. WENT A LITTLE
WARMER FOR LOWS TONIGHT FARTHER EAST WHERE RADIATIONAL COOLING WILL
BE LESS.

WARMING TREND ENSUES FOR FRI WITH BROAD UPPER-LEVEL RIDGING IN PLACE
OVER THE CWA. ECMWF H7 TEMPS INCREASE TO 10-12 DEG C ON FRI...SO IT
SHOULD BE QUITE A BIT WARMER WITH DRY/SUBSIDING CONDITIONS IN PLACE
ACROSS THE AREA AND NO MAJOR INHIBITING FACTORS FOR SOME DECENT SFC
HEATING. A QUICK SHOT OF MIDLVL MOISTURE WITH A WEAK WAVE TRAVERSING
THE FLOW SHOULD PRODUCE ISOLATED SHOWERS AND STORMS...GENERALLY IN
THE AFTN. GFS INSTABILITY PARAMETERS ARE UNIMPRESSIVE WITH LIS ONLY
AROUND -1 TO -2C AND LESS THAN 500 J/KG SBCAPE. CONVECTION ON FRI
SHOULD BE GARDEN VARIETY. SAT WILL BE THE WARMEST DAY OF THE PERIOD
AHEAD OF A MORE SIGNIFICANT SHORTWAVE MOVING ACROSS THE PAC NW. MID
LEVEL LAPSE RATES AROUND 8-9 DEG C/KM SUGGEST BETTER INSTABILITY ON
SAT...BETTER OVER THE PANHANDLE WHERE SURFACE CAPES MAY APPROACH
1000 J/KG. INCREASED POPS FOR SAT AFTN AND EVE WITH EXCELLENT MODEL
AGREEMENT BETWEEN THE GFS/NAM/ECMWF WITH INCREASING 700-500 MILLIBAR
QG ASCENT. GOOD CONVERGENCE ALONG THE COLD FRONT WILL HELP GENERATE
CONVECTION AS WELL. COLD FRONT BLASTS ACROSS THE CWA ON SAT AFTN AND
EARLY EVE...ENHANCING PCPN CHANCES AND SETTING THE STAGE FOR A COOL
START TO THE EXTENDED PERIOD. IT WILL BE BREEZY AS WELL WITH 35 KTS
OF FLOW AT H7...ESPECIALLY ALONG AND WEST OF THE LARAMIE RANGE ON
SAT AFTN.

.LONG TERM...(SUNDAY THROUGH THURSDAY)
ISSUED AT 313 PM MDT THU AUG 28 2014

A RELATIVELY COOL AND UNSETTLED END OF THE WEEKEND EXPECTED AS AN
UPPER TROUGH AND ASSOCIATED SFC FRONT MOVES THRU. THE ECMWF IS
6-12 HOURS QUICKER WITH FROPA MOVING IT THRU AT THE END OF THE
PREVIOUS PERIOD. COMPARATIVELY...THE GFS HOLDS IT BACK UNTIL LATER
SUNDAY. IN EITHER CASE...EXPECT AT LEAST SOME CONVECTIVE
DEVELOPMENT SUNDAY...WITH BEST COVERAGE DURING THE LATE AFTERNOON
AND OVR THE NRN NEBRASKA PANHANDLE. TROUGH AXIS WILL CLEAR THE
AREA SUNDAY NIGHT AND WHEN COMBINED WITH NIGHTTIME STABILIZATION
WILL BRING AN END TO SHOWER/THUNDERSTORM CHANCES BY NIGHTFALL.
ANOTHER FAST MOVING SHORTWAVE WILL TRACK ACROSS THE AREA AGAIN ON
MONDAY. THERE MAY BE JUST ENOUGH MOISTURE/INSTABILITY TO INITIATE
AN ISOLATED SHOWER/STORM LATE MONDAY AFTERNOON OR EARLY MONDAY
EVENING EAST OF A CHADRON TO ALLIANCE LINE. A MUCH DRIER AIR MASS
WILL ADVECT IN TUE-THU ALLOWING A LLVL THERMAL RIDGE TO AMPLIFY.
THE RESULT WILL BE FOR DRY AND WARMER CONDITIONS. SUNDAY WILL BE
THE COOLEST DAY OF THE PERIOD IN THE COOL POST-FRONTAL AIR MASS.
PROGD H7 TEMPS ONLY REACH AROUND 8C...WHICH WILL KEEP AFTERNOON
TEMPS IN THE 60S AND 70S. H7 TEMPS WILL RETURN TO 12-16C FOR MON-
THU...BRINGING HIGH TEMPS BACK WELL INTO THE 70S WEST AND 80S TO
NR 90S EAST BY WED-THU.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z FRIDAY AFTERNOON)
ISSUED AT 455 PM MDT THU AUG 28 2014

LOW PRESSURE THAT BROUGHT THE WIDESPREAD RAIN IS MOVING OFF TO THE
EAST. STILL SOME SHOWERS FOR AN HOUR OR SO OUT IN THE PANHANDLE
THAT SHOULD END EARLY THIS EVENING. WESTERLY WINDS WILL BRING
DOWNSLOPING CONDITIONS FRIDAY...WHICH WILL GIVE THE AREA VFR
CONDITIONS.

&&

.FIRE WEATHER...
ISSUED AT 313 PM MDT THU AUG 28 2014

NO MAJOR FIRE WEATHER CONCERNS OVER THE NEXT FEW DAYS. THE WEATHER
SYSTEM RESPONSIBLE FOR THE RECENT RAINFALL WILL MOVE TO THE EAST OF
THE AREA TONIGHT...GIVING WAY TO A GRADUAL WARMING TREND ON FRI AND
SAT. MINIMUM RELATIVE HUMIDITY VALUES WILL BE IN THE UPPER TEENS OR
LOW 20S FOR WESTERN ZONES. AFTERNOON SHOWERS AND THUNDERSTORMS MAY
PRODUCE GUSTY AND ERRATIC WINDS THROUGH THE REST OF THE WEEK...BUT
IN GENERAL STRONG STORMS ARE NOT EXPECTED. A STRONG COLD FRONT WILL
MOVE FROM WEST TO EAST ACROSS THE AREA ON SAT AFTN...GIVING WAY TO
BREEZY CONDITIONS WITH WIND GUSTS UP TO 40 MPH OVER PARTS OF CARBON
COUNTY. COOLER TEMPERATURES WILL FOLLOW FOR SUN.

&&

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

$$

SHORT TERM...HAMMER
LONG TERM...HAHN
AVIATION...CLAYCOMB
FIRE WEATHER...HAMMER







000
FXUS65 KCYS 282258
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
458 PM MDT THU AUG 28 2014

.SHORT TERM...(THIS EVENING THROUGH SATURDAY NIGHT)
ISSUED AT 313 PM MDT THU AUG 28 2014

LIGHT TO MODERATE RAIN HAS BEEN ONGOING FOR MUCH OF THE DAY ACROSS
SOUTHEAST WY AND THE WESTERN NE PANHANDLE. THIS IS OCCURRING ON THE
BACK SIDE OF A VIGOROUS MIDLVL SHORTWAVE CURRENTLY EXITING THE AREA
TO THE EAST OVER NE. WIDESPREAD CLOUDS/PCPN HAS WREAKED HAVOC ON THE
FCST TODAY WITH TEMPS ONLY IN THE 50S AT LAR AND CYS. AFTN RADAR AND
SATELLITE IMAGERY SHOWS THIS ACTIVITY HAS DECREASED IN COVERAGE AS
OF 20Z...AND BELIEVE THIS TREND SHOULD CONTINUE THROUGH THE EARLY
EVE HOURS AS BETTER UPPER-LEVEL SUPPORT SHIFTS TO THE EAST AND IS
REPLACED BY SUBSIDENCE BENEATH A SHORTWAVE RIDGE AXIS. VISIBLE SAT
INDICATES SKIES ARE CLEARING OVER OUR WESTERN ZONES...SO EXPECT A
QUIET OVERNIGHT PERIOD FOR THE MOST PART WITH MORE CLOUDS OVER THE
PANHANDLE. RAIN SHOULD END COMPLETELY BY 03-06Z FRI. WENT A LITTLE
WARMER FOR LOWS TONIGHT FARTHER EAST WHERE RADIATIONAL COOLING WILL
BE LESS.

WARMING TREND ENSUES FOR FRI WITH BROAD UPPER-LEVEL RIDGING IN PLACE
OVER THE CWA. ECMWF H7 TEMPS INCREASE TO 10-12 DEG C ON FRI...SO IT
SHOULD BE QUITE A BIT WARMER WITH DRY/SUBSIDING CONDITIONS IN PLACE
ACROSS THE AREA AND NO MAJOR INHIBITING FACTORS FOR SOME DECENT SFC
HEATING. A QUICK SHOT OF MIDLVL MOISTURE WITH A WEAK WAVE TRAVERSING
THE FLOW SHOULD PRODUCE ISOLATED SHOWERS AND STORMS...GENERALLY IN
THE AFTN. GFS INSTABILITY PARAMETERS ARE UNIMPRESSIVE WITH LIS ONLY
AROUND -1 TO -2C AND LESS THAN 500 J/KG SBCAPE. CONVECTION ON FRI
SHOULD BE GARDEN VARIETY. SAT WILL BE THE WARMEST DAY OF THE PERIOD
AHEAD OF A MORE SIGNIFICANT SHORTWAVE MOVING ACROSS THE PAC NW. MID
LEVEL LAPSE RATES AROUND 8-9 DEG C/KM SUGGEST BETTER INSTABILITY ON
SAT...BETTER OVER THE PANHANDLE WHERE SURFACE CAPES MAY APPROACH
1000 J/KG. INCREASED POPS FOR SAT AFTN AND EVE WITH EXCELLENT MODEL
AGREEMENT BETWEEN THE GFS/NAM/ECMWF WITH INCREASING 700-500 MILLIBAR
QG ASCENT. GOOD CONVERGENCE ALONG THE COLD FRONT WILL HELP GENERATE
CONVECTION AS WELL. COLD FRONT BLASTS ACROSS THE CWA ON SAT AFTN AND
EARLY EVE...ENHANCING PCPN CHANCES AND SETTING THE STAGE FOR A COOL
START TO THE EXTENDED PERIOD. IT WILL BE BREEZY AS WELL WITH 35 KTS
OF FLOW AT H7...ESPECIALLY ALONG AND WEST OF THE LARAMIE RANGE ON
SAT AFTN.

.LONG TERM...(SUNDAY THROUGH THURSDAY)
ISSUED AT 313 PM MDT THU AUG 28 2014

A RELATIVELY COOL AND UNSETTLED END OF THE WEEKEND EXPECTED AS AN
UPPER TROUGH AND ASSOCIATED SFC FRONT MOVES THRU. THE ECMWF IS
6-12 HOURS QUICKER WITH FROPA MOVING IT THRU AT THE END OF THE
PREVIOUS PERIOD. COMPARATIVELY...THE GFS HOLDS IT BACK UNTIL LATER
SUNDAY. IN EITHER CASE...EXPECT AT LEAST SOME CONVECTIVE
DEVELOPMENT SUNDAY...WITH BEST COVERAGE DURING THE LATE AFTERNOON
AND OVR THE NRN NEBRASKA PANHANDLE. TROUGH AXIS WILL CLEAR THE
AREA SUNDAY NIGHT AND WHEN COMBINED WITH NIGHTTIME STABILIZATION
WILL BRING AN END TO SHOWER/THUNDERSTORM CHANCES BY NIGHTFALL.
ANOTHER FAST MOVING SHORTWAVE WILL TRACK ACROSS THE AREA AGAIN ON
MONDAY. THERE MAY BE JUST ENOUGH MOISTURE/INSTABILITY TO INITIATE
AN ISOLATED SHOWER/STORM LATE MONDAY AFTERNOON OR EARLY MONDAY
EVENING EAST OF A CHADRON TO ALLIANCE LINE. A MUCH DRIER AIR MASS
WILL ADVECT IN TUE-THU ALLOWING A LLVL THERMAL RIDGE TO AMPLIFY.
THE RESULT WILL BE FOR DRY AND WARMER CONDITIONS. SUNDAY WILL BE
THE COOLEST DAY OF THE PERIOD IN THE COOL POST-FRONTAL AIR MASS.
PROGD H7 TEMPS ONLY REACH AROUND 8C...WHICH WILL KEEP AFTERNOON
TEMPS IN THE 60S AND 70S. H7 TEMPS WILL RETURN TO 12-16C FOR MON-
THU...BRINGING HIGH TEMPS BACK WELL INTO THE 70S WEST AND 80S TO
NR 90S EAST BY WED-THU.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z FRIDAY AFTERNOON)
ISSUED AT 455 PM MDT THU AUG 28 2014

LOW PRESSURE THAT BROUGHT THE WIDESPREAD RAIN IS MOVING OFF TO THE
EAST. STILL SOME SHOWERS FOR AN HOUR OR SO OUT IN THE PANHANDLE
THAT SHOULD END EARLY THIS EVENING. WESTERLY WINDS WILL BRING
DOWNSLOPING CONDITIONS FRIDAY...WHICH WILL GIVE THE AREA VFR
CONDITIONS.

&&

.FIRE WEATHER...
ISSUED AT 313 PM MDT THU AUG 28 2014

NO MAJOR FIRE WEATHER CONCERNS OVER THE NEXT FEW DAYS. THE WEATHER
SYSTEM RESPONSIBLE FOR THE RECENT RAINFALL WILL MOVE TO THE EAST OF
THE AREA TONIGHT...GIVING WAY TO A GRADUAL WARMING TREND ON FRI AND
SAT. MINIMUM RELATIVE HUMIDITY VALUES WILL BE IN THE UPPER TEENS OR
LOW 20S FOR WESTERN ZONES. AFTERNOON SHOWERS AND THUNDERSTORMS MAY
PRODUCE GUSTY AND ERRATIC WINDS THROUGH THE REST OF THE WEEK...BUT
IN GENERAL STRONG STORMS ARE NOT EXPECTED. A STRONG COLD FRONT WILL
MOVE FROM WEST TO EAST ACROSS THE AREA ON SAT AFTN...GIVING WAY TO
BREEZY CONDITIONS WITH WIND GUSTS UP TO 40 MPH OVER PARTS OF CARBON
COUNTY. COOLER TEMPERATURES WILL FOLLOW FOR SUN.

&&

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

$$

SHORT TERM...HAMMER
LONG TERM...HAHN
AVIATION...CLAYCOMB
FIRE WEATHER...HAMMER






000
FXUS63 KUNR 282132
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
332 PM MDT THU AUG 28 2014

.SHORT TERM...THIS EVENING THROUGH FRIDAY NIGHT
ISSUED AT 330 PM MDT THU AUG 28 2014

CURRENT SURFACE ANALYSIS SHOWS LOW PRESSURE OVER CENTRAL
NEB...WITH INVERTED TROF STRETCHING NORTHWARD ACROSS CENTRAL SD.
HIGH PRESSURE IS IN PLACE OVER THE CENTRAL ROCKIES. UPPER LEVEL
ANALYSIS SHOWS LOW NOW OVER FAR NORTHEAST CO...SLOWLY MOVING EAST-
SOUTHEAST. KUDX RADAR SHOWS ISOLATED TO SCATTERED SHOWERS FROM
CENTRAL SD TO FAR SOUTHWEST SD. THERE ARE A FEW LIGHTNING STRIKES
FROM TIME TO TIME WITH THE ACTIVITY OVER SOUTHERN SD. SKIES RANGE
FROM MOSTLY SUNNY OVER NORTHEAST WY AND FAR NORTHWEST SD TO MOSTLY
CLOUDY SOUTH AND EAST OF THE BLACK HILLS. TEMPS ARE IN THE 70S AND
LOWER 80S WITH LIGHT NORTHERLY WINDS IN MOST AREAS.

CONDITIONS WILL CONTINUE TO GRADUALLY IMPROVE THROUGH THE EVENING
FOR AREAS SOUTH AND EAST OF THE BLACK HILLS...WITH MOSTLY CLEAR
SKIES OVER WESTERN AND NORTHERN AREAS. HAVE ADDED CHANCES FOR
SHOWERS AND STORMS ACROSS SOUTH CENTRAL SD FOR THE EVENING HOURS AS
SYSTEM IS SLOWER TO MOVE OUT THAN WAS EXPECTED. WITH LOW LEVEL
MOISTURE HANGING AROUND OVER EASTERN PORTIONS OF THE CWA...HAVE KEPT
PATCHY FOG IN FOR MOST OF THE SD PLAINS. LOWS TONIGHT WILL BE IN THE
50S AND LOWER 60S. WINDS WILL MOSTLY BE LIGHT AND VARIABLE.

THE NEXT UPPER LEVEL WAVE...MUCH WEAKER THAN THE CURRENT ONE...WILL
MOVE QUICKLY INTO THE AREA ON FRIDAY...WITH INCREASING CHANCES FOR
SHOWERS AND THUNDERSTORMS THROUGH THE DAY FROM WEST TO EAST. A WEAK
COLD FRONT WILL ALSO SLIDE SOUTH INTO THE AREA WITH THE SHORTWAVE.
THE THREAT FOR SEVERE STORMS WILL REMAIN VERY LOW...BUT SUFFICIENT
INSTABILITY IS EXPECTED TO THE EAST OF THE BLACK HILLS IN THE
AFTERNOON TO POSSIBLY GET A STRONG STORM OR TWO GOING. HIGHS WILL BE
IN THE 80S...WITH SOME 70S ACROSS THE BLACK HILLS AND FAR
NORTHWESTERN SD. NORTHWESTERLY WINDS WILL INCREASE BEHIND THE FRONT
DURING THE LATE MORNING AND AFTERNOON...A BIT BREEZY AT TIMES OVER
THE WESTERN SD PLAINS. LINGERING SHOWERS SHOULD TAPER OFF QUICKLY IN
THE EVENING AS THE WAVE PUSHES EAST OF THE AREA.

&&

.LONG TERM...SATURDAY THROUGH THURSDAY
ISSUED AT 330 PM MDT THU AUG 28 2014

SATURDAY...SHORTWAVE RIDGE OVER THE CWA WILL QUICKLY MOVE INTO THE
MIDWEST DURING THE DAY AS A SHORTWAVE TROUGH ZIPS THROUGH MT INTO
ND/WY BY SATURDAY EVENING. SURFACE CYCLONE WILL DEVELOP OVER EASTERN
MT AND MOVES INTO THE CENTRAL DAKOTAS SATURDAY NIGHT. LOW LEVEL
MOISTURE CONVERGENCE ALONG THE FRONT WILL RESULT IN A NARROW BAND OF
1-2KJ/KG MLCAPE FROM SOUTHEAST MT INTO CENTRAL SD. 15-20M/S 0-6KM
BULK SHEAR SPREADS ACROSS NORTHWEST SD DURING PEAK HEATING. MLCIN
SHOULD BE BROKEN BY SURFACE FORCING AND LIFT AHEAD OF SHORTWAVE
RESULTING IN STRONG/POTENTIALLY SEVERE THUNDERSTORMS LATER SATURDAY
AFTERNOON INTO THE EVENING HOURS. STORMS MAY CONGEAL INTO A SMALL
MCS GIVEN DEVELOPING 50KT LOW LEVEL JET ACROSS THE EASTERN DAKOTAS
SATURDAY NIGHT. TEMPERATURES WILL BE TRICKY WITH VERY WARM READINGS
AHEAD OF THE LOW AND COOLER READINGS BEHIND THE FRONT.

SUNDAY THROUGH TUESDAY...UPPER TROUGH WITH EMBEDDED SHORTWAVES
SAUNTERS ACROSS THE DAKOTAS/SOUTH CENTRAL CANADA BRINGING SHRA/TSRA
CHANCES...ALTHOUGH COVERAGE SHOULD BE LOWER THAN RECENT MEMORY GIVEN
DRIER NORTHWEST FLOW. TEMPERATURES WILL BE NOTICEABLY COOLER SUNDAY
AND THEN WARM SLIGHTLY THROUGH TUESDAY.

WEDNESDAY/THURSDAY...UPPER RIDGE SHOULD BUILD INTO THE NORTHERN
PLAINS AS UPPER TROUGH DEEPENS OVER THE NORTHWEST US. DRIER AND
WARMER PATTERN MAY EVOLVE GIVEN THERMAL RIDGE AMPLIFICATION.

&&

.AVIATION...FOR THE 00Z TAFS THROUGH 00Z FRIDAY EVENING
ISSUED AT 330 PM MDT THU AUG 28 2014

SCATTERED -SHRA/-TSRA ALONG/EAST OF A LINE FROM KMGB TO
KCDR WILL CONTINUE TO SLIDE EAST THIS AFTERNOON...EXITING THE AREA
COMPLETELY THIS EVENING. AREAS IFR CIGS/VSBYS ASSOCIATED WITH THE
PRECIPITATION AND ST/BR WILL SHIFT EAST ALSO. BEHIND THESE
FEATURES...VFR CONDITIONS ARE EXPECTED THROUGH FRIDAY MORNING. THE
EXCEPTION WILL BE ON THE SD PLAINS LATER TONIGHT WHERE LOCAL MVFR
VSBYS DUE TO BR MAY OCCUR.

&&

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

$$

SHORT TERM...26
LONG TERM...HELGESON
AVIATION...HELGESON







000
FXUS63 KUNR 282132
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
332 PM MDT THU AUG 28 2014

.SHORT TERM...THIS EVENING THROUGH FRIDAY NIGHT
ISSUED AT 330 PM MDT THU AUG 28 2014

CURRENT SURFACE ANALYSIS SHOWS LOW PRESSURE OVER CENTRAL
NEB...WITH INVERTED TROF STRETCHING NORTHWARD ACROSS CENTRAL SD.
HIGH PRESSURE IS IN PLACE OVER THE CENTRAL ROCKIES. UPPER LEVEL
ANALYSIS SHOWS LOW NOW OVER FAR NORTHEAST CO...SLOWLY MOVING EAST-
SOUTHEAST. KUDX RADAR SHOWS ISOLATED TO SCATTERED SHOWERS FROM
CENTRAL SD TO FAR SOUTHWEST SD. THERE ARE A FEW LIGHTNING STRIKES
FROM TIME TO TIME WITH THE ACTIVITY OVER SOUTHERN SD. SKIES RANGE
FROM MOSTLY SUNNY OVER NORTHEAST WY AND FAR NORTHWEST SD TO MOSTLY
CLOUDY SOUTH AND EAST OF THE BLACK HILLS. TEMPS ARE IN THE 70S AND
LOWER 80S WITH LIGHT NORTHERLY WINDS IN MOST AREAS.

CONDITIONS WILL CONTINUE TO GRADUALLY IMPROVE THROUGH THE EVENING
FOR AREAS SOUTH AND EAST OF THE BLACK HILLS...WITH MOSTLY CLEAR
SKIES OVER WESTERN AND NORTHERN AREAS. HAVE ADDED CHANCES FOR
SHOWERS AND STORMS ACROSS SOUTH CENTRAL SD FOR THE EVENING HOURS AS
SYSTEM IS SLOWER TO MOVE OUT THAN WAS EXPECTED. WITH LOW LEVEL
MOISTURE HANGING AROUND OVER EASTERN PORTIONS OF THE CWA...HAVE KEPT
PATCHY FOG IN FOR MOST OF THE SD PLAINS. LOWS TONIGHT WILL BE IN THE
50S AND LOWER 60S. WINDS WILL MOSTLY BE LIGHT AND VARIABLE.

THE NEXT UPPER LEVEL WAVE...MUCH WEAKER THAN THE CURRENT ONE...WILL
MOVE QUICKLY INTO THE AREA ON FRIDAY...WITH INCREASING CHANCES FOR
SHOWERS AND THUNDERSTORMS THROUGH THE DAY FROM WEST TO EAST. A WEAK
COLD FRONT WILL ALSO SLIDE SOUTH INTO THE AREA WITH THE SHORTWAVE.
THE THREAT FOR SEVERE STORMS WILL REMAIN VERY LOW...BUT SUFFICIENT
INSTABILITY IS EXPECTED TO THE EAST OF THE BLACK HILLS IN THE
AFTERNOON TO POSSIBLY GET A STRONG STORM OR TWO GOING. HIGHS WILL BE
IN THE 80S...WITH SOME 70S ACROSS THE BLACK HILLS AND FAR
NORTHWESTERN SD. NORTHWESTERLY WINDS WILL INCREASE BEHIND THE FRONT
DURING THE LATE MORNING AND AFTERNOON...A BIT BREEZY AT TIMES OVER
THE WESTERN SD PLAINS. LINGERING SHOWERS SHOULD TAPER OFF QUICKLY IN
THE EVENING AS THE WAVE PUSHES EAST OF THE AREA.

&&

.LONG TERM...SATURDAY THROUGH THURSDAY
ISSUED AT 330 PM MDT THU AUG 28 2014

SATURDAY...SHORTWAVE RIDGE OVER THE CWA WILL QUICKLY MOVE INTO THE
MIDWEST DURING THE DAY AS A SHORTWAVE TROUGH ZIPS THROUGH MT INTO
ND/WY BY SATURDAY EVENING. SURFACE CYCLONE WILL DEVELOP OVER EASTERN
MT AND MOVES INTO THE CENTRAL DAKOTAS SATURDAY NIGHT. LOW LEVEL
MOISTURE CONVERGENCE ALONG THE FRONT WILL RESULT IN A NARROW BAND OF
1-2KJ/KG MLCAPE FROM SOUTHEAST MT INTO CENTRAL SD. 15-20M/S 0-6KM
BULK SHEAR SPREADS ACROSS NORTHWEST SD DURING PEAK HEATING. MLCIN
SHOULD BE BROKEN BY SURFACE FORCING AND LIFT AHEAD OF SHORTWAVE
RESULTING IN STRONG/POTENTIALLY SEVERE THUNDERSTORMS LATER SATURDAY
AFTERNOON INTO THE EVENING HOURS. STORMS MAY CONGEAL INTO A SMALL
MCS GIVEN DEVELOPING 50KT LOW LEVEL JET ACROSS THE EASTERN DAKOTAS
SATURDAY NIGHT. TEMPERATURES WILL BE TRICKY WITH VERY WARM READINGS
AHEAD OF THE LOW AND COOLER READINGS BEHIND THE FRONT.

SUNDAY THROUGH TUESDAY...UPPER TROUGH WITH EMBEDDED SHORTWAVES
SAUNTERS ACROSS THE DAKOTAS/SOUTH CENTRAL CANADA BRINGING SHRA/TSRA
CHANCES...ALTHOUGH COVERAGE SHOULD BE LOWER THAN RECENT MEMORY GIVEN
DRIER NORTHWEST FLOW. TEMPERATURES WILL BE NOTICEABLY COOLER SUNDAY
AND THEN WARM SLIGHTLY THROUGH TUESDAY.

WEDNESDAY/THURSDAY...UPPER RIDGE SHOULD BUILD INTO THE NORTHERN
PLAINS AS UPPER TROUGH DEEPENS OVER THE NORTHWEST US. DRIER AND
WARMER PATTERN MAY EVOLVE GIVEN THERMAL RIDGE AMPLIFICATION.

&&

.AVIATION...FOR THE 00Z TAFS THROUGH 00Z FRIDAY EVENING
ISSUED AT 330 PM MDT THU AUG 28 2014

SCATTERED -SHRA/-TSRA ALONG/EAST OF A LINE FROM KMGB TO
KCDR WILL CONTINUE TO SLIDE EAST THIS AFTERNOON...EXITING THE AREA
COMPLETELY THIS EVENING. AREAS IFR CIGS/VSBYS ASSOCIATED WITH THE
PRECIPITATION AND ST/BR WILL SHIFT EAST ALSO. BEHIND THESE
FEATURES...VFR CONDITIONS ARE EXPECTED THROUGH FRIDAY MORNING. THE
EXCEPTION WILL BE ON THE SD PLAINS LATER TONIGHT WHERE LOCAL MVFR
VSBYS DUE TO BR MAY OCCUR.

&&

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

$$

SHORT TERM...26
LONG TERM...HELGESON
AVIATION...HELGESON






000
FXUS65 KCYS 282114
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
314 PM MDT THU AUG 28 2014

.SHORT TERM...(THIS EVENING THROUGH SATURDAY NIGHT)
ISSUED AT 313 PM MDT THU AUG 28 2014

LIGHT TO MODERATE RAIN HAS BEEN ONGOING FOR MUCH OF THE DAY ACROSS
SOUTHEAST WY AND THE WESTERN NE PANHANDLE. THIS IS OCCURRING ON THE
BACK SIDE OF A VIGOROUS MIDLVL SHORTWAVE CURRENTLY EXITING THE AREA
TO THE EAST OVER NE. WIDESPREAD CLOUDS/PCPN HAS WREAKED HAVOC ON THE
FCST TODAY WITH TEMPS ONLY IN THE 50S AT LAR AND CYS. AFTN RADAR AND
SATELLITE IMAGERY SHOWS THIS ACTIVITY HAS DECREASED IN COVERAGE AS
OF 20Z...AND BELIEVE THIS TREND SHOULD CONTINUE THROUGH THE EARLY
EVE HOURS AS BETTER UPPER-LEVEL SUPPORT SHIFTS TO THE EAST AND IS
REPLACED BY SUBSIDENCE BENEATH A SHORTWAVE RIDGE AXIS. VISIBLE SAT
INDICATES SKIES ARE CLEARING OVER OUR WESTERN ZONES...SO EXPECT A
QUIET OVERNIGHT PERIOD FOR THE MOST PART WITH MORE CLOUDS OVER THE
PANHANDLE. RAIN SHOULD END COMPLETELY BY 03-06Z FRI. WENT A LITTLE
WARMER FOR LOWS TONIGHT FARTHER EAST WHERE RADIATIONAL COOLING WILL
BE LESS.

WARMING TREND ENSUES FOR FRI WITH BROAD UPPER-LEVEL RIDGING IN PLACE
OVER THE CWA. ECMWF H7 TEMPS INCREASE TO 10-12 DEG C ON FRI...SO IT
SHOULD BE QUITE A BIT WARMER WITH DRY/SUBSIDING CONDITIONS IN PLACE
ACROSS THE AREA AND NO MAJOR INHIBITING FACTORS FOR SOME DECENT SFC
HEATING. A QUICK SHOT OF MIDLVL MOISTURE WITH A WEAK WAVE TRAVERSING
THE FLOW SHOULD PRODUCE ISOLATED SHOWERS AND STORMS...GENERALLY IN
THE AFTN. GFS INSTABILITY PARAMETERS ARE UNIMPRESSIVE WITH LIS ONLY
AROUND -1 TO -2C AND LESS THAN 500 J/KG SBCAPE. CONVECTION ON FRI
SHOULD BE GARDEN VARIETY. SAT WILL BE THE WARMEST DAY OF THE PERIOD
AHEAD OF A MORE SIGNIFICANT SHORTWAVE MOVING ACROSS THE PAC NW. MID
LEVEL LAPSE RATES AROUND 8-9 DEG C/KM SUGGEST BETTER INSTABILITY ON
SAT...BETTER OVER THE PANHANDLE WHERE SURFACE CAPES MAY APPROACH
1000 J/KG. INCREASED POPS FOR SAT AFTN AND EVE WITH EXCELLENT MODEL
AGREEMENT BETWEEN THE GFS/NAM/ECMWF WITH INCREASING 700-500 MILLIBAR
QG ASCENT. GOOD CONVERGENCE ALONG THE COLD FRONT WILL HELP GENERATE
CONVECTION AS WELL. COLD FRONT BLASTS ACROSS THE CWA ON SAT AFTN AND
EARLY EVE...ENHANCING PCPN CHANCES AND SETTING THE STAGE FOR A COOL
START TO THE EXTENDED PERIOD. IT WILL BE BREEZY AS WELL WITH 35 KTS
OF FLOW AT H7...ESPECIALLY ALONG AND WEST OF THE LARAMIE RANGE ON
SAT AFTN.

.LONG TERM...(SUNDAY THROUGH THURSDAY)
ISSUED AT 313 PM MDT THU AUG 28 2014

A RELATIVELY COOL AND UNSETTLED END OF THE WEEKEND EXPECTED AS AN
UPPER TROUGH AND ASSOCIATED SFC FRONT MOVES THRU. THE ECMWF IS
6-12 HOURS QUICKER WITH FROPA MOVING IT THRU AT THE END OF THE
PREVIOUS PERIOD. COMPARATIVELY...THE GFS HOLDS IT BACK UNTIL LATER
SUNDAY. IN EITHER CASE...EXPECT AT LEAST SOME CONVECTIVE
DEVELOPMENT SUNDAY...WITH BEST COVERAGE DURING THE LATE AFTERNOON
AND OVR THE NRN NEBRASKA PANHANDLE. TROUGH AXIS WILL CLEAR THE
AREA SUNDAY NIGHT AND WHEN COMBINED WITH NIGHTTIME STABILIZATION
WILL BRING AN END TO SHOWER/THUNDERSTORM CHANCES BY NIGHTFALL.
ANOTHER FAST MOVING SHORTWAVE WILL TRACK ACROSS THE AREA AGAIN ON
MONDAY. THERE MAY BE JUST ENOUGH MOISTURE/INSTABILITY TO INITIATE
AN ISOLATED SHOWER/STORM LATE MONDAY AFTERNOON OR EARLY MONDAY
EVENING EAST OF A CHADRON TO ALLIANCE LINE. A MUCH DRIER AIR MASS
WILL ADVECT IN TUE-THU ALLOWING A LLVL THERMAL RIDGE TO AMPLIFY.
THE RESULT WILL BE FOR DRY AND WARMER CONDITIONS. SUNDAY WILL BE
THE COOLEST DAY OF THE PERIOD IN THE COOL POST-FRONTAL AIR MASS.
PROGD H7 TEMPS ONLY REACH AROUND 8C...WHICH WILL KEEP AFTERNOON
TEMPS IN THE 60S AND 70S. H7 TEMPS WILL RETURN TO 12-16C FOR MON-
THU...BRINGING HIGH TEMPS BACK WELL INTO THE 70S WEST AND 80S TO
NR 90S EAST BY WED-THU.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY MORNING)
ISSUED AT 1228 PM MDT THU AUG 28 2014

MAIN AVIATION CONCERNS TODAY WILL BE THE TIMING AND STRENGTH AS
BAND OF WRAP-AROUND RAIN SHOWERS AND EMBEDDED THUNDERSTORMS IMPACT
AREA TERMINALS. AT NOON...THIS BAND EXTENDED FROM NR KCDR/KAIA
SOUTHWEST TO KLAR. MVFR/IFR CIGS AND VSBS HAVE BEEN COMMON BENEATH
THIS AREA OF RAIN. IT WILL SLIDE EAST ACROSS THE KCYS...KBFF AND
KSNY THROUGH THE REST OF THE AFTERNOON. ALTHOUGH THE AREA HAS BEEN
FAIRLY COOL BENEATH THICK CLOUD-COVER...MAY SEE A FEW WEAK
EMBEDDED THUNDERSTORMS THIS AFTERNOON AS WELL. THIS BAND OF PRECIP
WILL SHIFT EAST OF ALL SITES BY 00Z...LEAVING CLEARING SKIES AND
VFR CONDITIONS THRU THE REMAINDER OF THE PERIOD.

&&

.FIRE WEATHER...
ISSUED AT 313 PM MDT THU AUG 28 2014

NO MAJOR FIRE WEATHER CONCERNS OVER THE NEXT FEW DAYS. THE WEATHER
SYSTEM RESPONSIBLE FOR THE RECENT RAINFALL WILL MOVE TO THE EAST OF
THE AREA TONIGHT...GIVING WAY TO A GRADUAL WARMING TREND ON FRI AND
SAT. MINIMUM RELATIVE HUMIDITY VALUES WILL BE IN THE UPPER TEENS OR
LOW 20S FOR WESTERN ZONES. AFTERNOON SHOWERS AND THUNDERSTORMS MAY
PRODUCE GUSTY AND ERRATIC WINDS THROUGH THE REST OF THE WEEK...BUT
IN GENERAL STRONG STORMS ARE NOT EXPECTED. A STRONG COLD FRONT WILL
MOVE FROM WEST TO EAST ACROSS THE AREA ON SAT AFTN...GIVING WAY TO
BREEZY CONDITIONS WITH WIND GUSTS UP TO 40 MPH OVER PARTS OF CARBON
COUNTY. COOLER TEMPERATURES WILL FOLLOW FOR SUN.

&&

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

&&

$$

SHORT TERM...HAMMER
LONG TERM...HAHN
AVIATION...HAHN
FIRE WEATHER...HAMMER





000
FXUS65 KCYS 282114
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
314 PM MDT THU AUG 28 2014

.SHORT TERM...(THIS EVENING THROUGH SATURDAY NIGHT)
ISSUED AT 313 PM MDT THU AUG 28 2014

LIGHT TO MODERATE RAIN HAS BEEN ONGOING FOR MUCH OF THE DAY ACROSS
SOUTHEAST WY AND THE WESTERN NE PANHANDLE. THIS IS OCCURRING ON THE
BACK SIDE OF A VIGOROUS MIDLVL SHORTWAVE CURRENTLY EXITING THE AREA
TO THE EAST OVER NE. WIDESPREAD CLOUDS/PCPN HAS WREAKED HAVOC ON THE
FCST TODAY WITH TEMPS ONLY IN THE 50S AT LAR AND CYS. AFTN RADAR AND
SATELLITE IMAGERY SHOWS THIS ACTIVITY HAS DECREASED IN COVERAGE AS
OF 20Z...AND BELIEVE THIS TREND SHOULD CONTINUE THROUGH THE EARLY
EVE HOURS AS BETTER UPPER-LEVEL SUPPORT SHIFTS TO THE EAST AND IS
REPLACED BY SUBSIDENCE BENEATH A SHORTWAVE RIDGE AXIS. VISIBLE SAT
INDICATES SKIES ARE CLEARING OVER OUR WESTERN ZONES...SO EXPECT A
QUIET OVERNIGHT PERIOD FOR THE MOST PART WITH MORE CLOUDS OVER THE
PANHANDLE. RAIN SHOULD END COMPLETELY BY 03-06Z FRI. WENT A LITTLE
WARMER FOR LOWS TONIGHT FARTHER EAST WHERE RADIATIONAL COOLING WILL
BE LESS.

WARMING TREND ENSUES FOR FRI WITH BROAD UPPER-LEVEL RIDGING IN PLACE
OVER THE CWA. ECMWF H7 TEMPS INCREASE TO 10-12 DEG C ON FRI...SO IT
SHOULD BE QUITE A BIT WARMER WITH DRY/SUBSIDING CONDITIONS IN PLACE
ACROSS THE AREA AND NO MAJOR INHIBITING FACTORS FOR SOME DECENT SFC
HEATING. A QUICK SHOT OF MIDLVL MOISTURE WITH A WEAK WAVE TRAVERSING
THE FLOW SHOULD PRODUCE ISOLATED SHOWERS AND STORMS...GENERALLY IN
THE AFTN. GFS INSTABILITY PARAMETERS ARE UNIMPRESSIVE WITH LIS ONLY
AROUND -1 TO -2C AND LESS THAN 500 J/KG SBCAPE. CONVECTION ON FRI
SHOULD BE GARDEN VARIETY. SAT WILL BE THE WARMEST DAY OF THE PERIOD
AHEAD OF A MORE SIGNIFICANT SHORTWAVE MOVING ACROSS THE PAC NW. MID
LEVEL LAPSE RATES AROUND 8-9 DEG C/KM SUGGEST BETTER INSTABILITY ON
SAT...BETTER OVER THE PANHANDLE WHERE SURFACE CAPES MAY APPROACH
1000 J/KG. INCREASED POPS FOR SAT AFTN AND EVE WITH EXCELLENT MODEL
AGREEMENT BETWEEN THE GFS/NAM/ECMWF WITH INCREASING 700-500 MILLIBAR
QG ASCENT. GOOD CONVERGENCE ALONG THE COLD FRONT WILL HELP GENERATE
CONVECTION AS WELL. COLD FRONT BLASTS ACROSS THE CWA ON SAT AFTN AND
EARLY EVE...ENHANCING PCPN CHANCES AND SETTING THE STAGE FOR A COOL
START TO THE EXTENDED PERIOD. IT WILL BE BREEZY AS WELL WITH 35 KTS
OF FLOW AT H7...ESPECIALLY ALONG AND WEST OF THE LARAMIE RANGE ON
SAT AFTN.

.LONG TERM...(SUNDAY THROUGH THURSDAY)
ISSUED AT 313 PM MDT THU AUG 28 2014

A RELATIVELY COOL AND UNSETTLED END OF THE WEEKEND EXPECTED AS AN
UPPER TROUGH AND ASSOCIATED SFC FRONT MOVES THRU. THE ECMWF IS
6-12 HOURS QUICKER WITH FROPA MOVING IT THRU AT THE END OF THE
PREVIOUS PERIOD. COMPARATIVELY...THE GFS HOLDS IT BACK UNTIL LATER
SUNDAY. IN EITHER CASE...EXPECT AT LEAST SOME CONVECTIVE
DEVELOPMENT SUNDAY...WITH BEST COVERAGE DURING THE LATE AFTERNOON
AND OVR THE NRN NEBRASKA PANHANDLE. TROUGH AXIS WILL CLEAR THE
AREA SUNDAY NIGHT AND WHEN COMBINED WITH NIGHTTIME STABILIZATION
WILL BRING AN END TO SHOWER/THUNDERSTORM CHANCES BY NIGHTFALL.
ANOTHER FAST MOVING SHORTWAVE WILL TRACK ACROSS THE AREA AGAIN ON
MONDAY. THERE MAY BE JUST ENOUGH MOISTURE/INSTABILITY TO INITIATE
AN ISOLATED SHOWER/STORM LATE MONDAY AFTERNOON OR EARLY MONDAY
EVENING EAST OF A CHADRON TO ALLIANCE LINE. A MUCH DRIER AIR MASS
WILL ADVECT IN TUE-THU ALLOWING A LLVL THERMAL RIDGE TO AMPLIFY.
THE RESULT WILL BE FOR DRY AND WARMER CONDITIONS. SUNDAY WILL BE
THE COOLEST DAY OF THE PERIOD IN THE COOL POST-FRONTAL AIR MASS.
PROGD H7 TEMPS ONLY REACH AROUND 8C...WHICH WILL KEEP AFTERNOON
TEMPS IN THE 60S AND 70S. H7 TEMPS WILL RETURN TO 12-16C FOR MON-
THU...BRINGING HIGH TEMPS BACK WELL INTO THE 70S WEST AND 80S TO
NR 90S EAST BY WED-THU.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY MORNING)
ISSUED AT 1228 PM MDT THU AUG 28 2014

MAIN AVIATION CONCERNS TODAY WILL BE THE TIMING AND STRENGTH AS
BAND OF WRAP-AROUND RAIN SHOWERS AND EMBEDDED THUNDERSTORMS IMPACT
AREA TERMINALS. AT NOON...THIS BAND EXTENDED FROM NR KCDR/KAIA
SOUTHWEST TO KLAR. MVFR/IFR CIGS AND VSBS HAVE BEEN COMMON BENEATH
THIS AREA OF RAIN. IT WILL SLIDE EAST ACROSS THE KCYS...KBFF AND
KSNY THROUGH THE REST OF THE AFTERNOON. ALTHOUGH THE AREA HAS BEEN
FAIRLY COOL BENEATH THICK CLOUD-COVER...MAY SEE A FEW WEAK
EMBEDDED THUNDERSTORMS THIS AFTERNOON AS WELL. THIS BAND OF PRECIP
WILL SHIFT EAST OF ALL SITES BY 00Z...LEAVING CLEARING SKIES AND
VFR CONDITIONS THRU THE REMAINDER OF THE PERIOD.

&&

.FIRE WEATHER...
ISSUED AT 313 PM MDT THU AUG 28 2014

NO MAJOR FIRE WEATHER CONCERNS OVER THE NEXT FEW DAYS. THE WEATHER
SYSTEM RESPONSIBLE FOR THE RECENT RAINFALL WILL MOVE TO THE EAST OF
THE AREA TONIGHT...GIVING WAY TO A GRADUAL WARMING TREND ON FRI AND
SAT. MINIMUM RELATIVE HUMIDITY VALUES WILL BE IN THE UPPER TEENS OR
LOW 20S FOR WESTERN ZONES. AFTERNOON SHOWERS AND THUNDERSTORMS MAY
PRODUCE GUSTY AND ERRATIC WINDS THROUGH THE REST OF THE WEEK...BUT
IN GENERAL STRONG STORMS ARE NOT EXPECTED. A STRONG COLD FRONT WILL
MOVE FROM WEST TO EAST ACROSS THE AREA ON SAT AFTN...GIVING WAY TO
BREEZY CONDITIONS WITH WIND GUSTS UP TO 40 MPH OVER PARTS OF CARBON
COUNTY. COOLER TEMPERATURES WILL FOLLOW FOR SUN.

&&

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

&&

$$

SHORT TERM...HAMMER
LONG TERM...HAHN
AVIATION...HAHN
FIRE WEATHER...HAMMER






000
FXUS65 KRIW 282009
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
209 PM MDT THU AUG 28 2014

.SHORT TERM...TONIGHT AND FRIDAY

FLOW IS A LITTLE MORE COMPLEX THAN THE MODELS ARE INDICATING TODAY
WITH COMBINATION OF SHORTWAVE APPROACHING FROM THE PACNW...UPPER
CIRCULATION SEEN IN WATER VAPOR ENTERING NWRN CA AND PACIFIC
MOISTURE JUST UPSTREAM OF THAT WAVE WHICH APPEARS TO BE REMNANT
MOISTURE FROM OLD HURRICANE LOWELL. A LITTLE BIT OF ALL OF THESE
WILL COME INTO PLAY OVER THE NEXT 24 TO 30 HOURS. THE FIRST TWO MAY
MOVE ACROSS ABOUT THE SAME TIME LATER TONIGHT INTO FRIDAY MORNING
WITH A SWATH OF SHOWERS FOR THE NORTH 1/3 TO 1/2. A FEW EVENING
SHOWERS OR THUNDERSTORMS MAY ALSO DEVELOP IN THE NW WHERE LIMITED
MOISTURE/INSTABILITY IS EXPECTED. THEN DURING THE DAY FRIDAY...THE
FRONTAL BOUNDARY LAID DOWN FROM OUR OVERNIGHT SYSTEM WILL DROP INTO
OUR NRN AND ERN ZONES AND MAY BE A FOCUS FOR A FEW STORMS FRIDAY
AFTERNOON. THE MOISTURE ASSOCIATED FROM OLD HURRICANE LOWELL MOVES
INTO THE WEST DURING THE DAY AND THEN SPREADS EAST INTO THE
AFTERNOON. FORECAST SOUNDINGS SHOW THE BEST INSTABILITY ALONG AND
BEHIND THE FRONT UP NORTH WITH CAPES OF 300-600 J/KG AND SOME MODEST
SHEAR. FURTHER SOUTH...IT`S DRIER BUT WITH DECENT HEATING WE SHOULD
SEE A FEW HUNDRED JOULES OF ENERGY AND THUS ISOLATED SHOWERS AND
THUNDERSTORMS. INCREASED OUR ISOLATED COVERAGE TO INCLUDE OUR
CENTRAL AND NRN SECTIONS.

.LONG TERM...FRIDAY NIGHT THROUGH THURSDAY

OVERALL...LR MDLS IN GOOD AGREEMENT THROUGHOUT THE FORECAST PERIOD
WITH ONLY MODEST DIVERGENCE FOUND FROM TUE NIGHT THRU THURSDAY AS
MDLS HAVE MAINLY TEMPORAL DIFFERENCES IN HANDLING THE NEXT MAJOR UPR
LVL TROF. AFTER THAT...THE MDLS START TO CONVERGE...GO FIGURE.

FRI NIGHT...QUICK HIT RIDGING IN PROGRESS AHEAD OF APPROACHING NW
COASTAL CONUS TROF WITH NOT MUCH IN THE WAY OF WX GOING ON AT THE
BEGINNING OF THE PERIOD EXCEPT FOR A FEW DIURNALLY FORCED MOUNTAIN
STORMS IN THE EVENING. HOWEVER...BY THE END OF THE FIRST
PERIOD...THE EWD TRANSLATION OF THE TROF WILL PUT INCREASED UPR
DIFLUENT FLOW ALONG WITH A MODEST INCREASE MOISTURE ACROSS THE NW/W
FA. AT THE SFC...DEVELOPING LOW PRESSURE AND A FRONT WILL ALSO
PROCEED UNDER THE INFLUENCE OF THE UPR TROF. THIS WILL ALL BRING
INCREASING CHANCES FOR SHRA OVR THE NW/W FA TO START THE DAY. AS SAT
WEARS ON...THE NOW PROGRESSIVE NATURE OF THE UPR LVLS WILL SPREAD
MUCH STRONGER UPR FLOW OVERHEAD RESULTING IN INCREASED NET UPWARD
LIFT. THIS TOGETHER WILL THE GREATLY IMPROVE CONVECTIVE CHANCES
ALONG WITH GROWTH POTENTIAL BY MID-DAY...WITH A FEW STRONG STORMS
EXPECTED. STRONGER CONVECTION...WITH (MOSTLY SMALL) HAIL
EARLY...EXPECTED ACROSS THE NRN FA...ESPECIALLY PARK COUNTY...BEFORE
TRANSITIONING TO MORE OF A STRONG WIND GUST/BRIEF HEAVY RAIN
SITUATION THROUGH THE REST OF THE DAY. SHEAR WILL COME IN THE FORM
OF SPEED SHEAR W/ HEIGHT THIS DAY...AS INCREASING UNIDIRECTIONAL SW
FLOW OVERRUNS THE CWA...LENDING ITSELF TO AMBIENT GUSTY WEST TO
SOUTHWEST WINDS TO BEGIN WITH. PUTTING CONVECTION INTO  THIS
ATMOSPHERE WILL ONLY INCREASE THE LIKELIHOOD FOR A FEW STRONG TO
MARGINALLY SVR GUSTS BY AFTERNOON AS STORM RACE TO THE NE AT 30 PLUS
MPH. SIGNIFICANT RAINFALL DOES NOT LOOK TO BE A PROBLEM.

SUNDAY...AS THE TROF CONTINUES CROSSING THE STATE FROM W TO E...
MUCH COOLER CONDITIONS FOR SURE...WITH CONTINUED GUSTY W TO WSW
WINDS ACROSS THE AREA WEST OF THE DIVIDE BEHIND THE EXITING SFC
FRONT. PRECIP CHCS WILL ALSO BE ENDING FROM CNTRL WY TO THE
ERN BORDER THROUGH THE DAY.

MONDAY THRU THURSDAY...ISOLATED TO WIDELY SCATTERED SHRA/ISO TSRA
MONDAY AFTERNOON ACROSS THE NRN/NERN FA AS THE STATE ENTERS NW UPR
FLOW AND STAYS UNDER A WEAKENING INFLUENCE FROM THE BROADENING TROF
AS IT EXPENDS EWD ACROSS THE CONUS. THE FA THEN ENTERS A MODEST
WARMING AND DRYING PERIOD WITH TEMPS RETURNING TO LOW END SEASONAL BY
MID WEEK...WITH ONLY EVER SO SLIGHT CHCS FOR DIURNAL MOUNTAINS ISO
SHRA/TSRA LATER WEDNESDAY...INCREASING TO PERHAPS WIDELY SCATTERED
CHCS THU AFTERNOON AS THE NEXT IN A CONSTANT PROGRESSION UPR LVL
TROFS BEGINS TO DIG INTO THE WRN CONUS AND INFLUENCE WX W OF THE
DIVIDE IN WY ONCE AGAIN.

&&

.AVIATION.../00Z ISSUANCE/
VFR CONDITIONS WILL THEN PREVAIL ACROSS THE REGION THE REMAINDER
OF THE DAY. A WEAK UPPER LEVEL DISTURBANCE WILL SPREAD WDLY SCT -SHRA
AND ISOLD -TSRA INTO THE NW MTNS...PRIMARILY NORTH OF A KJAC-KCOD
LINE THIS EVENING WITH THIS ACTIVITY SPREADING EAST AND A LITTLE
SOUTH OVERNIGHT PRIMARILY VCNTY AND NORTH OF KJAC- KWRL- KBYG LINE
WITH CIGS FL120-150.

ANOTHER SYSTEM WILL MOVE IN FROM THE WEST DURING THE DAY FRIDAY WITH
ISOLATED TO WIDELY SCATTERED THUNDERSTORMS DEVELOPING AND SPREAD EAST
ACROSS THE CENTRAL AND NORTHERN PART OF THE DISTRICT...MAINLY FROM
A KAFO...KPNA...KLND...KCPR LINE. VFR CONDITIONS WILL PREVAIL
ACROSS MOST OF THE AREA WITH JUST TEMPORARY MVFR VSBY OF 3-5 MILES
IN ANY HEAVIER SHOWERS OR THUNDERSTORMS.

&&

.FIRE WEATHER...
A FEW SHOWERS AND ISOLATED EVENING THUNDERSTORMS WILL BE POSSIBLE
ACROSS THE EXTREME NORTHWEST DURING THE EVENING...SPREADING EAST AND
A LITTLE SOUTH OVERNIGHT...WITH DRY CONDITIONS OTHERWISE. ANOTHER SYSTEM
WILL MOVE IN FROM THE WEST DURING THE DAY FRIDAY WHICH WILL RESULT IN
ISOLATED THUNDERSTORMS ACROSS THE CENTRAL AND NORTHERN PART OF THE
DISTRICT. THE MAIN THREAT FROM THESE WILL BE GUSTY WIND TO 45 MPH AND
LIGHTNING. ON SATURDAY...A STRONGER COLD FRONT WILL SWEEP EAST
ACROSS THE AREA WITH INCREASING SOUTHWEST WINDS AHEAD OF IT AND ISOLATED
TO WIDELY SCATTERED THUNDERSTORMS ALONG AND BEHIND THE COLD FRONT.
FIRE WEATHER CONCERNS WILL INCREASE AHEAD OF THE FRONT FOR A FEW
HOURS AS MIN RH`S DROP INTO THE TEENS AND SW WINDS BLOW 20 TO 35 MPH.
HOWEVER...ALL THE RECENT RAIN WILL LOWER THE THREAT AND PROBABLY ALLOW
THE MIN RH`S TO STAY ABOVE CRITICAL LEVELS. WE WILL CONTINUE TO
MONITOR.

&&

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

&&

$$

SHORT TERM...SKRBAC
LONG TERM...BRAUN
AVIATION...SKRBAC
FIRE WEATHER...SKRBAC










000
FXUS65 KRIW 282009
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
209 PM MDT THU AUG 28 2014

.SHORT TERM...TONIGHT AND FRIDAY

FLOW IS A LITTLE MORE COMPLEX THAN THE MODELS ARE INDICATING TODAY
WITH COMBINATION OF SHORTWAVE APPROACHING FROM THE PACNW...UPPER
CIRCULATION SEEN IN WATER VAPOR ENTERING NWRN CA AND PACIFIC
MOISTURE JUST UPSTREAM OF THAT WAVE WHICH APPEARS TO BE REMNANT
MOISTURE FROM OLD HURRICANE LOWELL. A LITTLE BIT OF ALL OF THESE
WILL COME INTO PLAY OVER THE NEXT 24 TO 30 HOURS. THE FIRST TWO MAY
MOVE ACROSS ABOUT THE SAME TIME LATER TONIGHT INTO FRIDAY MORNING
WITH A SWATH OF SHOWERS FOR THE NORTH 1/3 TO 1/2. A FEW EVENING
SHOWERS OR THUNDERSTORMS MAY ALSO DEVELOP IN THE NW WHERE LIMITED
MOISTURE/INSTABILITY IS EXPECTED. THEN DURING THE DAY FRIDAY...THE
FRONTAL BOUNDARY LAID DOWN FROM OUR OVERNIGHT SYSTEM WILL DROP INTO
OUR NRN AND ERN ZONES AND MAY BE A FOCUS FOR A FEW STORMS FRIDAY
AFTERNOON. THE MOISTURE ASSOCIATED FROM OLD HURRICANE LOWELL MOVES
INTO THE WEST DURING THE DAY AND THEN SPREADS EAST INTO THE
AFTERNOON. FORECAST SOUNDINGS SHOW THE BEST INSTABILITY ALONG AND
BEHIND THE FRONT UP NORTH WITH CAPES OF 300-600 J/KG AND SOME MODEST
SHEAR. FURTHER SOUTH...IT`S DRIER BUT WITH DECENT HEATING WE SHOULD
SEE A FEW HUNDRED JOULES OF ENERGY AND THUS ISOLATED SHOWERS AND
THUNDERSTORMS. INCREASED OUR ISOLATED COVERAGE TO INCLUDE OUR
CENTRAL AND NRN SECTIONS.

.LONG TERM...FRIDAY NIGHT THROUGH THURSDAY

OVERALL...LR MDLS IN GOOD AGREEMENT THROUGHOUT THE FORECAST PERIOD
WITH ONLY MODEST DIVERGENCE FOUND FROM TUE NIGHT THRU THURSDAY AS
MDLS HAVE MAINLY TEMPORAL DIFFERENCES IN HANDLING THE NEXT MAJOR UPR
LVL TROF. AFTER THAT...THE MDLS START TO CONVERGE...GO FIGURE.

FRI NIGHT...QUICK HIT RIDGING IN PROGRESS AHEAD OF APPROACHING NW
COASTAL CONUS TROF WITH NOT MUCH IN THE WAY OF WX GOING ON AT THE
BEGINNING OF THE PERIOD EXCEPT FOR A FEW DIURNALLY FORCED MOUNTAIN
STORMS IN THE EVENING. HOWEVER...BY THE END OF THE FIRST
PERIOD...THE EWD TRANSLATION OF THE TROF WILL PUT INCREASED UPR
DIFLUENT FLOW ALONG WITH A MODEST INCREASE MOISTURE ACROSS THE NW/W
FA. AT THE SFC...DEVELOPING LOW PRESSURE AND A FRONT WILL ALSO
PROCEED UNDER THE INFLUENCE OF THE UPR TROF. THIS WILL ALL BRING
INCREASING CHANCES FOR SHRA OVR THE NW/W FA TO START THE DAY. AS SAT
WEARS ON...THE NOW PROGRESSIVE NATURE OF THE UPR LVLS WILL SPREAD
MUCH STRONGER UPR FLOW OVERHEAD RESULTING IN INCREASED NET UPWARD
LIFT. THIS TOGETHER WILL THE GREATLY IMPROVE CONVECTIVE CHANCES
ALONG WITH GROWTH POTENTIAL BY MID-DAY...WITH A FEW STRONG STORMS
EXPECTED. STRONGER CONVECTION...WITH (MOSTLY SMALL) HAIL
EARLY...EXPECTED ACROSS THE NRN FA...ESPECIALLY PARK COUNTY...BEFORE
TRANSITIONING TO MORE OF A STRONG WIND GUST/BRIEF HEAVY RAIN
SITUATION THROUGH THE REST OF THE DAY. SHEAR WILL COME IN THE FORM
OF SPEED SHEAR W/ HEIGHT THIS DAY...AS INCREASING UNIDIRECTIONAL SW
FLOW OVERRUNS THE CWA...LENDING ITSELF TO AMBIENT GUSTY WEST TO
SOUTHWEST WINDS TO BEGIN WITH. PUTTING CONVECTION INTO  THIS
ATMOSPHERE WILL ONLY INCREASE THE LIKELIHOOD FOR A FEW STRONG TO
MARGINALLY SVR GUSTS BY AFTERNOON AS STORM RACE TO THE NE AT 30 PLUS
MPH. SIGNIFICANT RAINFALL DOES NOT LOOK TO BE A PROBLEM.

SUNDAY...AS THE TROF CONTINUES CROSSING THE STATE FROM W TO E...
MUCH COOLER CONDITIONS FOR SURE...WITH CONTINUED GUSTY W TO WSW
WINDS ACROSS THE AREA WEST OF THE DIVIDE BEHIND THE EXITING SFC
FRONT. PRECIP CHCS WILL ALSO BE ENDING FROM CNTRL WY TO THE
ERN BORDER THROUGH THE DAY.

MONDAY THRU THURSDAY...ISOLATED TO WIDELY SCATTERED SHRA/ISO TSRA
MONDAY AFTERNOON ACROSS THE NRN/NERN FA AS THE STATE ENTERS NW UPR
FLOW AND STAYS UNDER A WEAKENING INFLUENCE FROM THE BROADENING TROF
AS IT EXPENDS EWD ACROSS THE CONUS. THE FA THEN ENTERS A MODEST
WARMING AND DRYING PERIOD WITH TEMPS RETURNING TO LOW END SEASONAL BY
MID WEEK...WITH ONLY EVER SO SLIGHT CHCS FOR DIURNAL MOUNTAINS ISO
SHRA/TSRA LATER WEDNESDAY...INCREASING TO PERHAPS WIDELY SCATTERED
CHCS THU AFTERNOON AS THE NEXT IN A CONSTANT PROGRESSION UPR LVL
TROFS BEGINS TO DIG INTO THE WRN CONUS AND INFLUENCE WX W OF THE
DIVIDE IN WY ONCE AGAIN.

&&

.AVIATION.../00Z ISSUANCE/
VFR CONDITIONS WILL THEN PREVAIL ACROSS THE REGION THE REMAINDER
OF THE DAY. A WEAK UPPER LEVEL DISTURBANCE WILL SPREAD WDLY SCT -SHRA
AND ISOLD -TSRA INTO THE NW MTNS...PRIMARILY NORTH OF A KJAC-KCOD
LINE THIS EVENING WITH THIS ACTIVITY SPREADING EAST AND A LITTLE
SOUTH OVERNIGHT PRIMARILY VCNTY AND NORTH OF KJAC- KWRL- KBYG LINE
WITH CIGS FL120-150.

ANOTHER SYSTEM WILL MOVE IN FROM THE WEST DURING THE DAY FRIDAY WITH
ISOLATED TO WIDELY SCATTERED THUNDERSTORMS DEVELOPING AND SPREAD EAST
ACROSS THE CENTRAL AND NORTHERN PART OF THE DISTRICT...MAINLY FROM
A KAFO...KPNA...KLND...KCPR LINE. VFR CONDITIONS WILL PREVAIL
ACROSS MOST OF THE AREA WITH JUST TEMPORARY MVFR VSBY OF 3-5 MILES
IN ANY HEAVIER SHOWERS OR THUNDERSTORMS.

&&

.FIRE WEATHER...
A FEW SHOWERS AND ISOLATED EVENING THUNDERSTORMS WILL BE POSSIBLE
ACROSS THE EXTREME NORTHWEST DURING THE EVENING...SPREADING EAST AND
A LITTLE SOUTH OVERNIGHT...WITH DRY CONDITIONS OTHERWISE. ANOTHER SYSTEM
WILL MOVE IN FROM THE WEST DURING THE DAY FRIDAY WHICH WILL RESULT IN
ISOLATED THUNDERSTORMS ACROSS THE CENTRAL AND NORTHERN PART OF THE
DISTRICT. THE MAIN THREAT FROM THESE WILL BE GUSTY WIND TO 45 MPH AND
LIGHTNING. ON SATURDAY...A STRONGER COLD FRONT WILL SWEEP EAST
ACROSS THE AREA WITH INCREASING SOUTHWEST WINDS AHEAD OF IT AND ISOLATED
TO WIDELY SCATTERED THUNDERSTORMS ALONG AND BEHIND THE COLD FRONT.
FIRE WEATHER CONCERNS WILL INCREASE AHEAD OF THE FRONT FOR A FEW
HOURS AS MIN RH`S DROP INTO THE TEENS AND SW WINDS BLOW 20 TO 35 MPH.
HOWEVER...ALL THE RECENT RAIN WILL LOWER THE THREAT AND PROBABLY ALLOW
THE MIN RH`S TO STAY ABOVE CRITICAL LEVELS. WE WILL CONTINUE TO
MONITOR.

&&

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

&&

$$

SHORT TERM...SKRBAC
LONG TERM...BRAUN
AVIATION...SKRBAC
FIRE WEATHER...SKRBAC









000
FXUS65 KCYS 281829
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
1229 PM MDT THU AUG 28 2014

.UPDATE...
ISSUED AT 1039 AM MDT THU AUG 28 2014

A VIGOROUS MIDLVL SHORTWAVE CONTINUES TO ROTATE ACROSS THE WESTERN
NE PANHANDLE THIS MORNING. WRAP-AROUND MOISTURE ON THE BACK SIDE
OF THIS SYSTEM IS CONTRIBUTING TO WIDESPREAD SHOWERS OR STRATIFORM
RAIN ALONG A LINE FROM CENTENNIAL TO WHEATLAND. HAVE RECENTLY SEEN
SOME HIGHER ECHOS IN CENTRAL PLATTE COUNTY...AS WELL AS SOME AREAS
ALONG THE WEST EDGE OF THE LARAMIE RANGE. 1-2 INCHES OF RAIN ON
WED MORNING AND AFTN LENDS SOME CONCERN TO FLOODING POTENTIAL IF
RATES ARE HIGH ENOUGH AND/OR WE SEE MORE TRAINING. FFMP DATA ALSO
SHOWS AREAS NORTHEAST OF BOSLER HAVE ALREADY RECEIVED CLOSE TO 2
INCHES OF RAIN TODAY. WILL CONTINUE TO MONITOR CLOSELY THROUGH
THE DAY FOR POSSIBLE STATEMENTS...BUT CURRENT WEBCAMS SUGGEST THE
GROUND IS ABSORBING THINGS WELL. ONGOING CLOUDS AND RAIN WILL MAKE
IT TOUGH TO REACH FCST HIGHS...SO IN A RECENT UPDATE HAVE CUT BACK
ON TEMPS BY 5-10 DEGREES WHERE MOST OF THE PRECIP IS OCCURRING PER
THE LATEST KCYS RADAR LOOP. ALSO BUMPED UP POPS INTO THE LIKELY
CATEGORY FOR FAR SOUTHEAST WY AND WESTERN NE...EXPANDING EASTWARD
WITH TIME.

&&

.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 425 AM MDT THU AUG 28 2014

PREDAWN WATER VAPOR IMAGERY SHOWED THE UPPER LOW OVER SOUTHERN WY/NORTHERN
CO. AT THE SURFACE...A FRONT EXTENDED FROM THE MID-ATLANTIC REGION ACROSS
THE TN VALLEY TO A LOW ALONG THE CENTRAL NE/KS BORDER THEN SOUTHWEST
TO ANOTHER LOW IN SOUTHEAST CO. A LARGE CLUSTER OF STRONG CONVECTION
DEVELOPED ALONG AND JUST NORTH OF THE FRONT OVER SOUTH CENTRAL/SOUTHEAST
NE. LIGHT SHOWERS WERE DEVELOPING AND MOVING SOUTHWEST FROM EAST CENTRAL
TO SOUTH CENTRAL WY.

THE 00Z CONSENSUS MODEL GUIDANCE WEAKENS THE UPPER LOW TO AN OPEN WAVE
THIS MORNING OVER THE HIGH PLAINS...PROGRESSING SLOWLY EAST INTO THE
CENTRAL GREAT PLAINS FRIDAY. CONVECTIVE COVERAGE TODAY WILL BE LESS
THAN THE PAST FEW DAYS WITH THE RISK FOR HEAVY RAINFALL FROM THE CENTRAL
PLAINS TO THE UPPER MS VALLEY. WRAPAROUND MOISTURE OVER NORTHERN AND
WESTERN PORTIONS OF THE CWA THIS MORNING WILL GRADUALLY SLIDE EAST
THIS AFTERNOON AND EARLY EVENING. THERE WILL BE ENOUGH INSTABILITY FROM
DAYTIME HEATING FOR SCATTERED SHOWERS/TSTORMS THIS AFTERNOON...ESPECIALLY
SOUTH OF A RAWLINS WY TO ALLIANCE NE LINE. HIGH TEMPERATURES TODAY WILL
BE SLIGHTLY WARMER WITH 70S FOR LOWER ELEVATIONS.

A FEW LINGERING SHOWERS OR TSTORMS OVER THE EXTREME SOUTHERN NE PANHANDLE
EARLY THIS EVENING. OTHERWISE...SUBSIDENCE AND DRIER MORE STABLE AIRMASS
WILL SPREAD WEST TO EAST WITH THE APPROACH AND PASSAGE OF A SHORTWAVE
RIDGE.

A WEAK SHORTWAVE OVER THE NORTHERN ROCKIES EARLY FRIDAY MORNING MAKES
A BEELINE FOR THE NORTHERN HIGH PLAINS FRIDAY AFTERNOON. MOISTURE WILL
BE LIMITED WITH MARGINAL INSTABILITY FOR ISOLATED AFTERNOON TSTORMS
OVER THE MOUNTAINS AND NEARBY PLAINS OF SOUTHEAST WY. HIGH TEMPERATURES
WILL WARM INTO THE 80S EAST OF THE LARAMIE RANGE...WITH 60S AND 70S
WEST. EXPECT TRANQUIL CONDITIONS FRIDAY NIGHT WITH THE PASSAGE OF
ANOTHER SHORTWAVE RIDGE.

LATEST MODELS CONTINUE TO DEPICT A MORE SIGNIFICANT UPPER TROUGH TAKING
SHAPE OVER THE GREAT BASIN AND PACIFIC NORTHWEST SATURDAY. A RATHER
STRONG PACIFIC COLD FRONT WILL BE MOVING THROUGH NORTHERN AND WESTERN
WY DURING THE AFTERNOON. 700MB WINDS INCREASE TO 35 KT FROM THE WEST
AND SOUTHWEST. PACIFIC MOISTURE WILL ALSO INCREASE BY LATE AFTERNOON
WITH WIDELY SCATTERED SHOWERS/TSTORMS DEVELOPING ALONG AND WEST OF A
CHADRON NE TO CHEYENNE WY LINE. A TIGHTER SURFACE PRESSURE GRADIENT
WILL CREATE RATHER BREEZY WEST TO SOUTHWEST WINDS. IT WILL BE A WARM
AFTERNOON WITH HIGHS IN THE 80S TO LOWER 90S FOR THE PLAINS...WITH 60S
AND 70S WEST.

.LONG TERM...(SATURDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 350 AM MDT THU AUG 28 2014

MEDIUM AND LONG RANGE MODELS IN GOOD AGREEMENT INTO EARLY NEXT WEEK.
THE MAIN FORECAST CONCERN WILL BE A BROAD UPPER LEVEL TROUGH AND
ASSOCIATED COLD FRONT FOR LATER THIS WEEKEND. THE COLD FRONT APPEARS
TO BE RATHER STRONG FOR THIS TIME OF THE YEAR...WITH GUSTY WINDS
POSSIBLE ALONG WITH RAIN SHOWERS/TSTORMS OVER MOST OF THE AREA.
CANNOT RULE OUT SOME SNOWFALL ACROSS THE HIGH MOUNTAINS AS THIS FRONT
MOVES ACROSS THE AREA SATURDAY NIGHT AND INTO EARLY SUNDAY. MODELS
IN GOOD AGREEMENT WITH THE TIMING...ALTHOUGH THE GFS IS NOTICEABLY
MORE PROGRESSIVE AND DRIER. PREFER THE ECMWF AND GEM AT THIS TIME
SINCE BOTH THESE MODELS DID BETTER WITH THIS LAST STORM SYSTEM 3
DAYS OUT IN TERMS OF TIMING AND EVOLUTION. INCREASED POP ABOVE 30
PERCENT ACROSS MOST OF THE FORECAST AREA FOR SCATTERED SHOWERS AND
ISOLATED TSTORMS. INCREASED WINDS AS WELL...ALTHOUGH MODEL
SOUNDINGS ARE SUGGESTING SUSTAINED WESTERLY WINDS BETWEEN 20 TO 30
MPH AND GUSTS AROUND 40 MPH. DID NOT INCREASE WINDS QUITE THAT
HIGH SINCE THE ECMWF SHOWS MUCH LOWER WIND SPEEDS SUNDAY AFTERNOON.
TEMPERATURES WILL REMAIN ON THE COOL SIDE AND GENERALLY IN THE
UPPER 60S TO UPPER 70S...WARMEST ACROSS THE NEBRASKA PANHANDLE.

MODELS THEN INDICATE A DRYING TREND FOR NEXT WEEK AS THE SOUTHWESTERN
MONSOON MAY BE ENDING...WHICH IS TYPICAL IN THE LATE SUMMER. MODELS
AND ENSEMBLES ALSO SHOW WHAT APPEARS TO BE A TRANSITIONAL PERIOD IN
THE PATTERN...AS THE POLAR JET STREAM BECOMES MORE DEFINED BY DAY
6 AND 7 NEAR THE CANADIAN BORDER. THIS WILL RESULT IN QUASI-ZONAL
FLOW OVER THE WESTERN TWO THIRDS OF THE UNITED STATES. HOWEVER...THE
ECMWF AND GEM DO SHOW AN UPPER LEVEL DISTURBANCE MOVING SOUTHEAST
ACROSS THE HIGH PLAINS LATE ON MONDAY...SO KEPT LOW POP OVER EAST
CENTRAL WYOMING AND NORTHWEST NEBRASKA. OTHERWISE...TEMPERATURES
WILL GRADUALLY INCREASE TO AROUND NORMAL FOR THIS TIME OF THE YEAR
WITH HIGHS AROUND 80 ALONG AND WEST OF THE LARAMIE RANGE AND RANGING
FROM THE LOW 80S TO THE LOW 90S ACROSS THE HIGH PLAINS EAST OF THE
LARAMIE RANGE BY WEDNESDAY AFTERNOON.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY MORNING)
ISSUED AT 1228 AM MDT THU AUG 28 2014

MAIN AVIATION CONCERNS TODAY WILL BE THE TIMING AND STRENGTH AS
BAND OF WRAP-AROUND RAIN SHOWERS AND EMBEDDED THUNDERSTORMS IMPACT
AREA TERMINALS. AT NOON...THIS BAND EXTENDED FROM NR KCDR/KAIA
SOUTHWEST TO KLAR. MVFR/IFR CIGS AND VSBS HAVE BEEN COMMON BENEATH
THIS AREA OF RAIN. IT WILL SLIDE EAST ACROSS THE KCYS...KBFF AND
KSNY THROUGH THE REST OF THE AFTERNOON. ALTHOUGH THE AREA HAS BEEN
FAIRLY COOL BENEATH THICK CLOUD-COVER...MAY SEE A FEW WEAK
EMBEDDED THUNDERSTORMS THIS AFTERNOON AS WELL. THIS BAND OF PRECIP
WILL SHIFT EAST OF ALL SITES BY 00Z...LEAVING CLEARING SKIES AND
VFR CONDITONS THRU THE REMAINDER OF THE PERIOD.

&&

.FIRE WEATHER...
ISSUED AT 255 AM MDT THU AUG 28 2014

THE UPPER LOW PRESSURE SYSTEM RESPONSIBLE FOR THE INCLEMENT WEATHER
THE PAST FEW DAYS WILL MOVE EAST FROM THE CENTRAL ROCKIES TODAY TO
THE CENTRAL GREAT PLAINS FRIDAY. A MORE SCATTERED COVERAGE OF SHOWERS
AND THUNDERSTORMS IS EXPECTED TODAY. MAINLY DRIER AND WARMER CONDITIONS
ARE FORECAST FOR FRIDAY WITH JUST A SLIGHT CHANCE OF AFTERNOON
THUNDERSTORMS OVER THE MOUNTAINS AND PORTIONS OF EAST CENTRAL WYOMING
WITH THE PASSAGE OF A WEAK UPPER LEVEL DISTURBANCE. ISOLATED TO
SCATTERED MAINLY AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS ARE
FORECAST SATURDAY AND SUNDAY AS A MORE SIGNIFICANT UPPER TROUGH AND
COLD FRONT AFFECT THE DISTRICTS. WARM TEMPERATURES SATURDAY WILL TURN
COOLER SUNDAY FOLLOWING THE COLD FRONTAL PASSAGE. THE TIGHT PRESSURE
GRADIENT WILL RESULT IN GUSTY WESTERLY WINDS THIS WEEKEND.

&&

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

$$

UPDATE...HAMMER
SHORT TERM...JAMSKI
LONG TERM...TJT
AVIATION...HAHN
FIRE WEATHER...JAMSKI







000
FXUS65 KCYS 281829
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
1229 PM MDT THU AUG 28 2014

.UPDATE...
ISSUED AT 1039 AM MDT THU AUG 28 2014

A VIGOROUS MIDLVL SHORTWAVE CONTINUES TO ROTATE ACROSS THE WESTERN
NE PANHANDLE THIS MORNING. WRAP-AROUND MOISTURE ON THE BACK SIDE
OF THIS SYSTEM IS CONTRIBUTING TO WIDESPREAD SHOWERS OR STRATIFORM
RAIN ALONG A LINE FROM CENTENNIAL TO WHEATLAND. HAVE RECENTLY SEEN
SOME HIGHER ECHOS IN CENTRAL PLATTE COUNTY...AS WELL AS SOME AREAS
ALONG THE WEST EDGE OF THE LARAMIE RANGE. 1-2 INCHES OF RAIN ON
WED MORNING AND AFTN LENDS SOME CONCERN TO FLOODING POTENTIAL IF
RATES ARE HIGH ENOUGH AND/OR WE SEE MORE TRAINING. FFMP DATA ALSO
SHOWS AREAS NORTHEAST OF BOSLER HAVE ALREADY RECEIVED CLOSE TO 2
INCHES OF RAIN TODAY. WILL CONTINUE TO MONITOR CLOSELY THROUGH
THE DAY FOR POSSIBLE STATEMENTS...BUT CURRENT WEBCAMS SUGGEST THE
GROUND IS ABSORBING THINGS WELL. ONGOING CLOUDS AND RAIN WILL MAKE
IT TOUGH TO REACH FCST HIGHS...SO IN A RECENT UPDATE HAVE CUT BACK
ON TEMPS BY 5-10 DEGREES WHERE MOST OF THE PRECIP IS OCCURRING PER
THE LATEST KCYS RADAR LOOP. ALSO BUMPED UP POPS INTO THE LIKELY
CATEGORY FOR FAR SOUTHEAST WY AND WESTERN NE...EXPANDING EASTWARD
WITH TIME.

&&

.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 425 AM MDT THU AUG 28 2014

PREDAWN WATER VAPOR IMAGERY SHOWED THE UPPER LOW OVER SOUTHERN WY/NORTHERN
CO. AT THE SURFACE...A FRONT EXTENDED FROM THE MID-ATLANTIC REGION ACROSS
THE TN VALLEY TO A LOW ALONG THE CENTRAL NE/KS BORDER THEN SOUTHWEST
TO ANOTHER LOW IN SOUTHEAST CO. A LARGE CLUSTER OF STRONG CONVECTION
DEVELOPED ALONG AND JUST NORTH OF THE FRONT OVER SOUTH CENTRAL/SOUTHEAST
NE. LIGHT SHOWERS WERE DEVELOPING AND MOVING SOUTHWEST FROM EAST CENTRAL
TO SOUTH CENTRAL WY.

THE 00Z CONSENSUS MODEL GUIDANCE WEAKENS THE UPPER LOW TO AN OPEN WAVE
THIS MORNING OVER THE HIGH PLAINS...PROGRESSING SLOWLY EAST INTO THE
CENTRAL GREAT PLAINS FRIDAY. CONVECTIVE COVERAGE TODAY WILL BE LESS
THAN THE PAST FEW DAYS WITH THE RISK FOR HEAVY RAINFALL FROM THE CENTRAL
PLAINS TO THE UPPER MS VALLEY. WRAPAROUND MOISTURE OVER NORTHERN AND
WESTERN PORTIONS OF THE CWA THIS MORNING WILL GRADUALLY SLIDE EAST
THIS AFTERNOON AND EARLY EVENING. THERE WILL BE ENOUGH INSTABILITY FROM
DAYTIME HEATING FOR SCATTERED SHOWERS/TSTORMS THIS AFTERNOON...ESPECIALLY
SOUTH OF A RAWLINS WY TO ALLIANCE NE LINE. HIGH TEMPERATURES TODAY WILL
BE SLIGHTLY WARMER WITH 70S FOR LOWER ELEVATIONS.

A FEW LINGERING SHOWERS OR TSTORMS OVER THE EXTREME SOUTHERN NE PANHANDLE
EARLY THIS EVENING. OTHERWISE...SUBSIDENCE AND DRIER MORE STABLE AIRMASS
WILL SPREAD WEST TO EAST WITH THE APPROACH AND PASSAGE OF A SHORTWAVE
RIDGE.

A WEAK SHORTWAVE OVER THE NORTHERN ROCKIES EARLY FRIDAY MORNING MAKES
A BEELINE FOR THE NORTHERN HIGH PLAINS FRIDAY AFTERNOON. MOISTURE WILL
BE LIMITED WITH MARGINAL INSTABILITY FOR ISOLATED AFTERNOON TSTORMS
OVER THE MOUNTAINS AND NEARBY PLAINS OF SOUTHEAST WY. HIGH TEMPERATURES
WILL WARM INTO THE 80S EAST OF THE LARAMIE RANGE...WITH 60S AND 70S
WEST. EXPECT TRANQUIL CONDITIONS FRIDAY NIGHT WITH THE PASSAGE OF
ANOTHER SHORTWAVE RIDGE.

LATEST MODELS CONTINUE TO DEPICT A MORE SIGNIFICANT UPPER TROUGH TAKING
SHAPE OVER THE GREAT BASIN AND PACIFIC NORTHWEST SATURDAY. A RATHER
STRONG PACIFIC COLD FRONT WILL BE MOVING THROUGH NORTHERN AND WESTERN
WY DURING THE AFTERNOON. 700MB WINDS INCREASE TO 35 KT FROM THE WEST
AND SOUTHWEST. PACIFIC MOISTURE WILL ALSO INCREASE BY LATE AFTERNOON
WITH WIDELY SCATTERED SHOWERS/TSTORMS DEVELOPING ALONG AND WEST OF A
CHADRON NE TO CHEYENNE WY LINE. A TIGHTER SURFACE PRESSURE GRADIENT
WILL CREATE RATHER BREEZY WEST TO SOUTHWEST WINDS. IT WILL BE A WARM
AFTERNOON WITH HIGHS IN THE 80S TO LOWER 90S FOR THE PLAINS...WITH 60S
AND 70S WEST.

.LONG TERM...(SATURDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 350 AM MDT THU AUG 28 2014

MEDIUM AND LONG RANGE MODELS IN GOOD AGREEMENT INTO EARLY NEXT WEEK.
THE MAIN FORECAST CONCERN WILL BE A BROAD UPPER LEVEL TROUGH AND
ASSOCIATED COLD FRONT FOR LATER THIS WEEKEND. THE COLD FRONT APPEARS
TO BE RATHER STRONG FOR THIS TIME OF THE YEAR...WITH GUSTY WINDS
POSSIBLE ALONG WITH RAIN SHOWERS/TSTORMS OVER MOST OF THE AREA.
CANNOT RULE OUT SOME SNOWFALL ACROSS THE HIGH MOUNTAINS AS THIS FRONT
MOVES ACROSS THE AREA SATURDAY NIGHT AND INTO EARLY SUNDAY. MODELS
IN GOOD AGREEMENT WITH THE TIMING...ALTHOUGH THE GFS IS NOTICEABLY
MORE PROGRESSIVE AND DRIER. PREFER THE ECMWF AND GEM AT THIS TIME
SINCE BOTH THESE MODELS DID BETTER WITH THIS LAST STORM SYSTEM 3
DAYS OUT IN TERMS OF TIMING AND EVOLUTION. INCREASED POP ABOVE 30
PERCENT ACROSS MOST OF THE FORECAST AREA FOR SCATTERED SHOWERS AND
ISOLATED TSTORMS. INCREASED WINDS AS WELL...ALTHOUGH MODEL
SOUNDINGS ARE SUGGESTING SUSTAINED WESTERLY WINDS BETWEEN 20 TO 30
MPH AND GUSTS AROUND 40 MPH. DID NOT INCREASE WINDS QUITE THAT
HIGH SINCE THE ECMWF SHOWS MUCH LOWER WIND SPEEDS SUNDAY AFTERNOON.
TEMPERATURES WILL REMAIN ON THE COOL SIDE AND GENERALLY IN THE
UPPER 60S TO UPPER 70S...WARMEST ACROSS THE NEBRASKA PANHANDLE.

MODELS THEN INDICATE A DRYING TREND FOR NEXT WEEK AS THE SOUTHWESTERN
MONSOON MAY BE ENDING...WHICH IS TYPICAL IN THE LATE SUMMER. MODELS
AND ENSEMBLES ALSO SHOW WHAT APPEARS TO BE A TRANSITIONAL PERIOD IN
THE PATTERN...AS THE POLAR JET STREAM BECOMES MORE DEFINED BY DAY
6 AND 7 NEAR THE CANADIAN BORDER. THIS WILL RESULT IN QUASI-ZONAL
FLOW OVER THE WESTERN TWO THIRDS OF THE UNITED STATES. HOWEVER...THE
ECMWF AND GEM DO SHOW AN UPPER LEVEL DISTURBANCE MOVING SOUTHEAST
ACROSS THE HIGH PLAINS LATE ON MONDAY...SO KEPT LOW POP OVER EAST
CENTRAL WYOMING AND NORTHWEST NEBRASKA. OTHERWISE...TEMPERATURES
WILL GRADUALLY INCREASE TO AROUND NORMAL FOR THIS TIME OF THE YEAR
WITH HIGHS AROUND 80 ALONG AND WEST OF THE LARAMIE RANGE AND RANGING
FROM THE LOW 80S TO THE LOW 90S ACROSS THE HIGH PLAINS EAST OF THE
LARAMIE RANGE BY WEDNESDAY AFTERNOON.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY MORNING)
ISSUED AT 1228 AM MDT THU AUG 28 2014

MAIN AVIATION CONCERNS TODAY WILL BE THE TIMING AND STRENGTH AS
BAND OF WRAP-AROUND RAIN SHOWERS AND EMBEDDED THUNDERSTORMS IMPACT
AREA TERMINALS. AT NOON...THIS BAND EXTENDED FROM NR KCDR/KAIA
SOUTHWEST TO KLAR. MVFR/IFR CIGS AND VSBS HAVE BEEN COMMON BENEATH
THIS AREA OF RAIN. IT WILL SLIDE EAST ACROSS THE KCYS...KBFF AND
KSNY THROUGH THE REST OF THE AFTERNOON. ALTHOUGH THE AREA HAS BEEN
FAIRLY COOL BENEATH THICK CLOUD-COVER...MAY SEE A FEW WEAK
EMBEDDED THUNDERSTORMS THIS AFTERNOON AS WELL. THIS BAND OF PRECIP
WILL SHIFT EAST OF ALL SITES BY 00Z...LEAVING CLEARING SKIES AND
VFR CONDITONS THRU THE REMAINDER OF THE PERIOD.

&&

.FIRE WEATHER...
ISSUED AT 255 AM MDT THU AUG 28 2014

THE UPPER LOW PRESSURE SYSTEM RESPONSIBLE FOR THE INCLEMENT WEATHER
THE PAST FEW DAYS WILL MOVE EAST FROM THE CENTRAL ROCKIES TODAY TO
THE CENTRAL GREAT PLAINS FRIDAY. A MORE SCATTERED COVERAGE OF SHOWERS
AND THUNDERSTORMS IS EXPECTED TODAY. MAINLY DRIER AND WARMER CONDITIONS
ARE FORECAST FOR FRIDAY WITH JUST A SLIGHT CHANCE OF AFTERNOON
THUNDERSTORMS OVER THE MOUNTAINS AND PORTIONS OF EAST CENTRAL WYOMING
WITH THE PASSAGE OF A WEAK UPPER LEVEL DISTURBANCE. ISOLATED TO
SCATTERED MAINLY AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS ARE
FORECAST SATURDAY AND SUNDAY AS A MORE SIGNIFICANT UPPER TROUGH AND
COLD FRONT AFFECT THE DISTRICTS. WARM TEMPERATURES SATURDAY WILL TURN
COOLER SUNDAY FOLLOWING THE COLD FRONTAL PASSAGE. THE TIGHT PRESSURE
GRADIENT WILL RESULT IN GUSTY WESTERLY WINDS THIS WEEKEND.

&&

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

$$

UPDATE...HAMMER
SHORT TERM...JAMSKI
LONG TERM...TJT
AVIATION...HAHN
FIRE WEATHER...JAMSKI






000
FXUS65 KRIW 281735
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
1135 AM MDT THU AUG 28 2014

.SHORT TERM...TODAY THROUGH SATURDAY NIGHT

...UPDATE...
LOW CLOUDS AND FOG HAVE FINALLY DISSIPATED LEAVING A SUNNY TO
MOSTLY SUNNY SKY.

LIGHT SHOWERS NOTED ACROSS THE SOUTHEASTERN HALF OF THE FORECAST
AREA THIS MORNING. THE CORE OF THE LOW PRESSURE IS OVER
NORTHEASTERN COLORADO AND IS CONTINUING ON ITS EASTWARD
PROGRESSION. SHOWERS WILL CONTINUE TO TAPER OFF AS THE SYSTEM
MOVES FURTHER EAST...WITH NATRONA AND SWEETWATER COUNTIES LOOKING
TO HOLD ON TO SHOWER ACTIVITY THE LONGEST.

DRY NORTHWEST FLOW BUILDS OVER THE AREA THIS EVENING UNDER THE
INFLUENCE OF A FLATTENED RIDGING PATTERN. THIS SYSTEM WILL ALLOW
SURGES OF MOISTURE TO MOVE INTO THE FORECAST AREA...ESPECIALLY
NORTHWESTERN WYOMING. SHOWERS AND THUNDERSTORMS WILL BE
POSSIBLE...WITH ASSOCIATED THREATS OF GUSTY WIND AND LIGHTNING
ACTIVITY.

ANOTHER TROUGH ADVANCES TOWARDS THE FORECAST AREA BY SATURDAY
MORNING...BRINGING INCREASING SOUTHWEST FLOW OVER THE AREA. GUSTY
WINDS WILL BE POSSIBLE UNDER THIS FLOW...WITH DRIER CONDITIONS NOTED
OVER SOUTHERN WYOMING AHEAD OF THE TROUGH. THIS MAY LEAD TO SOME
ELEVATED FIRE WEATHER CONCERNS...BUT THE SITUATION WILL CONTINUE TO
BE MONITORED.

THE TROUGH WILL STRENGTHEN OVER THE AREA SATURDAY AFTERNOON AND
EVENING...WITH MORE WIDESPREAD SHOWERS AND THUNDERSTORMS
ANTICIPATED. AGAIN...GUSTY WIND AND LIGHTNING WILL BE THE PRIMARY
THREATS WITH STORM ACTIVITY OVER THE NEXT FEW DAYS. THE TROUGH WILL
GENERALLY MOVE THROUGH THE AREA BY SUNDAY MORNING...WITH A RETURN OF
DRY NORTHWEST FLOW.

.LONG TERM...SUNDAY THROUGH WEDNESDAY NIGHT

FAST MOVING FLOW ALOFT DURING MOST OF THE EXTENDED PERIOD WITH A
MID/UPPER LEVEL TROUGH PASSAGE EARLY SUNDAY. MEDIUM RANGE MODELS
GENERALLY HAVE CLOUDS AND MOISTURE EAST OF THE FORECAST AREA BY
SUNDAY AFTERNOON. IN FACT...FAIR WEATHER SHOULD PREVAIL WEST OF
THE DIVIDE ON SUNDAY. THINKING DOWNWARD FORCING BEHIND THIS TROUGH
TO RESULT IN BREEZY TO WINDY CONDITIONS SUNDAY AFTERNOON AND EVENING.

AFTER THIS TIME...FAST ZONAL FLOW OVER WYOMING WITH NEAR NORMAL
TEMPERATURES EXPECTED. MONDAY AND TUESDAY MORNINGS TO START OFF
RELATIVELY COOL. THERE LOOKS TO BE VERY LITTLE SUPPORT ALOFT FOR
PRECIPITATION WITH THIS PATTERN. WILL CALL IT MOSTLY DRY AND
BREEZY THROUGH WEDNESDAY. HOWEVER...CANNOT RULE OUT ISOLATED
SHOWERS OR THUNDERSTORMS EACH DAY ACROSS THE FORECAST AREA.

.AVIATION.../18Z ISSUANCE/

VFR CONDITIONS WILL THEN PREVAIL ACROSS THE REGION THIS AFTERNOON
WITH NO SIGNIFICANT WINDS. A WEAK UPPER LEVEL DISTURBANCE WILL
SPREAD WDLY SCT -SHRA AND ISOLD -TSRA INTO THE NW MTNS...PRIMARILY
NORTH OF A KJAC-KCOD LINE...LATE THIS AFTERNOON AND EVENING WITH
THIS ACTIVITY SPREADING EAST AND A LITTLE SOUTH OVERNIGHT PRIMARILY
VCNTY AND NORTH OF KJAC-KWRL-KBYG LINE WITH CIGS FL120-150.

ANOTHER SYSTEM WILL MOVE IN FROM THE WEST DURING THE DAY FRIDAY WITH
ISOLATED TO WIDELY SCATTERED THUNDERSTORMS DEVELOPING AND SPREAD EAST
ACROSS THE CENTRAL AND NORTHERN PART OF THE DISTRICT...MAINLY FROM
A KJAC...KPNA...KLND...KCPR LINE. VFR CONDITIONS WILL PREVAIL ACROSS
MOST OF THE AREA WITH JUST TEMPORARY MVFR VSBY OF 3-5 MILES IN ANY
HEAVIER SHOWERS OR THUNDERSTORMS.

.FIRE WEATHER...

WEAKENING SHOWERS AND THUNDERSTORMS EXPECTED OVER THE AREA THIS
MORNING...WITH BUILDING DRY WEST TO NORTHWEST FLOW. A FEW SHOWERS
WILL BE POSSIBLE ACROSS THE EXTREME NORTHWEST DURING THE EVENING AND
OVERNIGHT HOURS...WITH DRY CONDITIONS OTHERWISE. AN APPROACHING WAVE
OF LOW PRESSURE WILL TURN THE FLOW TO THE SOUTHWEST LATE FRIDAY AND
INTO SATURDAY. AHEAD OF THE TROUGH AXIS...CONDITIONS ACROSS SOUTHERN
WYOMING COULD BECOME BREEZY AND DRY...RAISING SOME FIRE WEATHER
CONCERNS. THE THREAT WILL BE SHORT LIVED...WITH SHOWERS AND
THUNDERSTORMS ANTICIPATED ACROSS THE AREA BY SATURDAY AFTERNOON.

&&

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

&&

$$

SHORT TERM...BRANHAM
LONG TERM...KPL
AVIATION...SKRBAC
FIRE WEATHER...BRANHAM







000
FXUS65 KRIW 281735
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
1135 AM MDT THU AUG 28 2014

.SHORT TERM...TODAY THROUGH SATURDAY NIGHT

...UPDATE...
LOW CLOUDS AND FOG HAVE FINALLY DISSIPATED LEAVING A SUNNY TO
MOSTLY SUNNY SKY.

LIGHT SHOWERS NOTED ACROSS THE SOUTHEASTERN HALF OF THE FORECAST
AREA THIS MORNING. THE CORE OF THE LOW PRESSURE IS OVER
NORTHEASTERN COLORADO AND IS CONTINUING ON ITS EASTWARD
PROGRESSION. SHOWERS WILL CONTINUE TO TAPER OFF AS THE SYSTEM
MOVES FURTHER EAST...WITH NATRONA AND SWEETWATER COUNTIES LOOKING
TO HOLD ON TO SHOWER ACTIVITY THE LONGEST.

DRY NORTHWEST FLOW BUILDS OVER THE AREA THIS EVENING UNDER THE
INFLUENCE OF A FLATTENED RIDGING PATTERN. THIS SYSTEM WILL ALLOW
SURGES OF MOISTURE TO MOVE INTO THE FORECAST AREA...ESPECIALLY
NORTHWESTERN WYOMING. SHOWERS AND THUNDERSTORMS WILL BE
POSSIBLE...WITH ASSOCIATED THREATS OF GUSTY WIND AND LIGHTNING
ACTIVITY.

ANOTHER TROUGH ADVANCES TOWARDS THE FORECAST AREA BY SATURDAY
MORNING...BRINGING INCREASING SOUTHWEST FLOW OVER THE AREA. GUSTY
WINDS WILL BE POSSIBLE UNDER THIS FLOW...WITH DRIER CONDITIONS NOTED
OVER SOUTHERN WYOMING AHEAD OF THE TROUGH. THIS MAY LEAD TO SOME
ELEVATED FIRE WEATHER CONCERNS...BUT THE SITUATION WILL CONTINUE TO
BE MONITORED.

THE TROUGH WILL STRENGTHEN OVER THE AREA SATURDAY AFTERNOON AND
EVENING...WITH MORE WIDESPREAD SHOWERS AND THUNDERSTORMS
ANTICIPATED. AGAIN...GUSTY WIND AND LIGHTNING WILL BE THE PRIMARY
THREATS WITH STORM ACTIVITY OVER THE NEXT FEW DAYS. THE TROUGH WILL
GENERALLY MOVE THROUGH THE AREA BY SUNDAY MORNING...WITH A RETURN OF
DRY NORTHWEST FLOW.

.LONG TERM...SUNDAY THROUGH WEDNESDAY NIGHT

FAST MOVING FLOW ALOFT DURING MOST OF THE EXTENDED PERIOD WITH A
MID/UPPER LEVEL TROUGH PASSAGE EARLY SUNDAY. MEDIUM RANGE MODELS
GENERALLY HAVE CLOUDS AND MOISTURE EAST OF THE FORECAST AREA BY
SUNDAY AFTERNOON. IN FACT...FAIR WEATHER SHOULD PREVAIL WEST OF
THE DIVIDE ON SUNDAY. THINKING DOWNWARD FORCING BEHIND THIS TROUGH
TO RESULT IN BREEZY TO WINDY CONDITIONS SUNDAY AFTERNOON AND EVENING.

AFTER THIS TIME...FAST ZONAL FLOW OVER WYOMING WITH NEAR NORMAL
TEMPERATURES EXPECTED. MONDAY AND TUESDAY MORNINGS TO START OFF
RELATIVELY COOL. THERE LOOKS TO BE VERY LITTLE SUPPORT ALOFT FOR
PRECIPITATION WITH THIS PATTERN. WILL CALL IT MOSTLY DRY AND
BREEZY THROUGH WEDNESDAY. HOWEVER...CANNOT RULE OUT ISOLATED
SHOWERS OR THUNDERSTORMS EACH DAY ACROSS THE FORECAST AREA.

.AVIATION.../18Z ISSUANCE/

VFR CONDITIONS WILL THEN PREVAIL ACROSS THE REGION THIS AFTERNOON
WITH NO SIGNIFICANT WINDS. A WEAK UPPER LEVEL DISTURBANCE WILL
SPREAD WDLY SCT -SHRA AND ISOLD -TSRA INTO THE NW MTNS...PRIMARILY
NORTH OF A KJAC-KCOD LINE...LATE THIS AFTERNOON AND EVENING WITH
THIS ACTIVITY SPREADING EAST AND A LITTLE SOUTH OVERNIGHT PRIMARILY
VCNTY AND NORTH OF KJAC-KWRL-KBYG LINE WITH CIGS FL120-150.

ANOTHER SYSTEM WILL MOVE IN FROM THE WEST DURING THE DAY FRIDAY WITH
ISOLATED TO WIDELY SCATTERED THUNDERSTORMS DEVELOPING AND SPREAD EAST
ACROSS THE CENTRAL AND NORTHERN PART OF THE DISTRICT...MAINLY FROM
A KJAC...KPNA...KLND...KCPR LINE. VFR CONDITIONS WILL PREVAIL ACROSS
MOST OF THE AREA WITH JUST TEMPORARY MVFR VSBY OF 3-5 MILES IN ANY
HEAVIER SHOWERS OR THUNDERSTORMS.

.FIRE WEATHER...

WEAKENING SHOWERS AND THUNDERSTORMS EXPECTED OVER THE AREA THIS
MORNING...WITH BUILDING DRY WEST TO NORTHWEST FLOW. A FEW SHOWERS
WILL BE POSSIBLE ACROSS THE EXTREME NORTHWEST DURING THE EVENING AND
OVERNIGHT HOURS...WITH DRY CONDITIONS OTHERWISE. AN APPROACHING WAVE
OF LOW PRESSURE WILL TURN THE FLOW TO THE SOUTHWEST LATE FRIDAY AND
INTO SATURDAY. AHEAD OF THE TROUGH AXIS...CONDITIONS ACROSS SOUTHERN
WYOMING COULD BECOME BREEZY AND DRY...RAISING SOME FIRE WEATHER
CONCERNS. THE THREAT WILL BE SHORT LIVED...WITH SHOWERS AND
THUNDERSTORMS ANTICIPATED ACROSS THE AREA BY SATURDAY AFTERNOON.

&&

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

&&

$$

SHORT TERM...BRANHAM
LONG TERM...KPL
AVIATION...SKRBAC
FIRE WEATHER...BRANHAM







000
FXUS65 KRIW 281735
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
1135 AM MDT THU AUG 28 2014

.SHORT TERM...TODAY THROUGH SATURDAY NIGHT

...UPDATE...
LOW CLOUDS AND FOG HAVE FINALLY DISSIPATED LEAVING A SUNNY TO
MOSTLY SUNNY SKY.

LIGHT SHOWERS NOTED ACROSS THE SOUTHEASTERN HALF OF THE FORECAST
AREA THIS MORNING. THE CORE OF THE LOW PRESSURE IS OVER
NORTHEASTERN COLORADO AND IS CONTINUING ON ITS EASTWARD
PROGRESSION. SHOWERS WILL CONTINUE TO TAPER OFF AS THE SYSTEM
MOVES FURTHER EAST...WITH NATRONA AND SWEETWATER COUNTIES LOOKING
TO HOLD ON TO SHOWER ACTIVITY THE LONGEST.

DRY NORTHWEST FLOW BUILDS OVER THE AREA THIS EVENING UNDER THE
INFLUENCE OF A FLATTENED RIDGING PATTERN. THIS SYSTEM WILL ALLOW
SURGES OF MOISTURE TO MOVE INTO THE FORECAST AREA...ESPECIALLY
NORTHWESTERN WYOMING. SHOWERS AND THUNDERSTORMS WILL BE
POSSIBLE...WITH ASSOCIATED THREATS OF GUSTY WIND AND LIGHTNING
ACTIVITY.

ANOTHER TROUGH ADVANCES TOWARDS THE FORECAST AREA BY SATURDAY
MORNING...BRINGING INCREASING SOUTHWEST FLOW OVER THE AREA. GUSTY
WINDS WILL BE POSSIBLE UNDER THIS FLOW...WITH DRIER CONDITIONS NOTED
OVER SOUTHERN WYOMING AHEAD OF THE TROUGH. THIS MAY LEAD TO SOME
ELEVATED FIRE WEATHER CONCERNS...BUT THE SITUATION WILL CONTINUE TO
BE MONITORED.

THE TROUGH WILL STRENGTHEN OVER THE AREA SATURDAY AFTERNOON AND
EVENING...WITH MORE WIDESPREAD SHOWERS AND THUNDERSTORMS
ANTICIPATED. AGAIN...GUSTY WIND AND LIGHTNING WILL BE THE PRIMARY
THREATS WITH STORM ACTIVITY OVER THE NEXT FEW DAYS. THE TROUGH WILL
GENERALLY MOVE THROUGH THE AREA BY SUNDAY MORNING...WITH A RETURN OF
DRY NORTHWEST FLOW.

.LONG TERM...SUNDAY THROUGH WEDNESDAY NIGHT

FAST MOVING FLOW ALOFT DURING MOST OF THE EXTENDED PERIOD WITH A
MID/UPPER LEVEL TROUGH PASSAGE EARLY SUNDAY. MEDIUM RANGE MODELS
GENERALLY HAVE CLOUDS AND MOISTURE EAST OF THE FORECAST AREA BY
SUNDAY AFTERNOON. IN FACT...FAIR WEATHER SHOULD PREVAIL WEST OF
THE DIVIDE ON SUNDAY. THINKING DOWNWARD FORCING BEHIND THIS TROUGH
TO RESULT IN BREEZY TO WINDY CONDITIONS SUNDAY AFTERNOON AND EVENING.

AFTER THIS TIME...FAST ZONAL FLOW OVER WYOMING WITH NEAR NORMAL
TEMPERATURES EXPECTED. MONDAY AND TUESDAY MORNINGS TO START OFF
RELATIVELY COOL. THERE LOOKS TO BE VERY LITTLE SUPPORT ALOFT FOR
PRECIPITATION WITH THIS PATTERN. WILL CALL IT MOSTLY DRY AND
BREEZY THROUGH WEDNESDAY. HOWEVER...CANNOT RULE OUT ISOLATED
SHOWERS OR THUNDERSTORMS EACH DAY ACROSS THE FORECAST AREA.

.AVIATION.../18Z ISSUANCE/

VFR CONDITIONS WILL THEN PREVAIL ACROSS THE REGION THIS AFTERNOON
WITH NO SIGNIFICANT WINDS. A WEAK UPPER LEVEL DISTURBANCE WILL
SPREAD WDLY SCT -SHRA AND ISOLD -TSRA INTO THE NW MTNS...PRIMARILY
NORTH OF A KJAC-KCOD LINE...LATE THIS AFTERNOON AND EVENING WITH
THIS ACTIVITY SPREADING EAST AND A LITTLE SOUTH OVERNIGHT PRIMARILY
VCNTY AND NORTH OF KJAC-KWRL-KBYG LINE WITH CIGS FL120-150.

ANOTHER SYSTEM WILL MOVE IN FROM THE WEST DURING THE DAY FRIDAY WITH
ISOLATED TO WIDELY SCATTERED THUNDERSTORMS DEVELOPING AND SPREAD EAST
ACROSS THE CENTRAL AND NORTHERN PART OF THE DISTRICT...MAINLY FROM
A KJAC...KPNA...KLND...KCPR LINE. VFR CONDITIONS WILL PREVAIL ACROSS
MOST OF THE AREA WITH JUST TEMPORARY MVFR VSBY OF 3-5 MILES IN ANY
HEAVIER SHOWERS OR THUNDERSTORMS.

.FIRE WEATHER...

WEAKENING SHOWERS AND THUNDERSTORMS EXPECTED OVER THE AREA THIS
MORNING...WITH BUILDING DRY WEST TO NORTHWEST FLOW. A FEW SHOWERS
WILL BE POSSIBLE ACROSS THE EXTREME NORTHWEST DURING THE EVENING AND
OVERNIGHT HOURS...WITH DRY CONDITIONS OTHERWISE. AN APPROACHING WAVE
OF LOW PRESSURE WILL TURN THE FLOW TO THE SOUTHWEST LATE FRIDAY AND
INTO SATURDAY. AHEAD OF THE TROUGH AXIS...CONDITIONS ACROSS SOUTHERN
WYOMING COULD BECOME BREEZY AND DRY...RAISING SOME FIRE WEATHER
CONCERNS. THE THREAT WILL BE SHORT LIVED...WITH SHOWERS AND
THUNDERSTORMS ANTICIPATED ACROSS THE AREA BY SATURDAY AFTERNOON.

&&

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

&&

$$

SHORT TERM...BRANHAM
LONG TERM...KPL
AVIATION...SKRBAC
FIRE WEATHER...BRANHAM







000
FXUS65 KRIW 281735
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
1135 AM MDT THU AUG 28 2014

.SHORT TERM...TODAY THROUGH SATURDAY NIGHT

...UPDATE...
LOW CLOUDS AND FOG HAVE FINALLY DISSIPATED LEAVING A SUNNY TO
MOSTLY SUNNY SKY.

LIGHT SHOWERS NOTED ACROSS THE SOUTHEASTERN HALF OF THE FORECAST
AREA THIS MORNING. THE CORE OF THE LOW PRESSURE IS OVER
NORTHEASTERN COLORADO AND IS CONTINUING ON ITS EASTWARD
PROGRESSION. SHOWERS WILL CONTINUE TO TAPER OFF AS THE SYSTEM
MOVES FURTHER EAST...WITH NATRONA AND SWEETWATER COUNTIES LOOKING
TO HOLD ON TO SHOWER ACTIVITY THE LONGEST.

DRY NORTHWEST FLOW BUILDS OVER THE AREA THIS EVENING UNDER THE
INFLUENCE OF A FLATTENED RIDGING PATTERN. THIS SYSTEM WILL ALLOW
SURGES OF MOISTURE TO MOVE INTO THE FORECAST AREA...ESPECIALLY
NORTHWESTERN WYOMING. SHOWERS AND THUNDERSTORMS WILL BE
POSSIBLE...WITH ASSOCIATED THREATS OF GUSTY WIND AND LIGHTNING
ACTIVITY.

ANOTHER TROUGH ADVANCES TOWARDS THE FORECAST AREA BY SATURDAY
MORNING...BRINGING INCREASING SOUTHWEST FLOW OVER THE AREA. GUSTY
WINDS WILL BE POSSIBLE UNDER THIS FLOW...WITH DRIER CONDITIONS NOTED
OVER SOUTHERN WYOMING AHEAD OF THE TROUGH. THIS MAY LEAD TO SOME
ELEVATED FIRE WEATHER CONCERNS...BUT THE SITUATION WILL CONTINUE TO
BE MONITORED.

THE TROUGH WILL STRENGTHEN OVER THE AREA SATURDAY AFTERNOON AND
EVENING...WITH MORE WIDESPREAD SHOWERS AND THUNDERSTORMS
ANTICIPATED. AGAIN...GUSTY WIND AND LIGHTNING WILL BE THE PRIMARY
THREATS WITH STORM ACTIVITY OVER THE NEXT FEW DAYS. THE TROUGH WILL
GENERALLY MOVE THROUGH THE AREA BY SUNDAY MORNING...WITH A RETURN OF
DRY NORTHWEST FLOW.

.LONG TERM...SUNDAY THROUGH WEDNESDAY NIGHT

FAST MOVING FLOW ALOFT DURING MOST OF THE EXTENDED PERIOD WITH A
MID/UPPER LEVEL TROUGH PASSAGE EARLY SUNDAY. MEDIUM RANGE MODELS
GENERALLY HAVE CLOUDS AND MOISTURE EAST OF THE FORECAST AREA BY
SUNDAY AFTERNOON. IN FACT...FAIR WEATHER SHOULD PREVAIL WEST OF
THE DIVIDE ON SUNDAY. THINKING DOWNWARD FORCING BEHIND THIS TROUGH
TO RESULT IN BREEZY TO WINDY CONDITIONS SUNDAY AFTERNOON AND EVENING.

AFTER THIS TIME...FAST ZONAL FLOW OVER WYOMING WITH NEAR NORMAL
TEMPERATURES EXPECTED. MONDAY AND TUESDAY MORNINGS TO START OFF
RELATIVELY COOL. THERE LOOKS TO BE VERY LITTLE SUPPORT ALOFT FOR
PRECIPITATION WITH THIS PATTERN. WILL CALL IT MOSTLY DRY AND
BREEZY THROUGH WEDNESDAY. HOWEVER...CANNOT RULE OUT ISOLATED
SHOWERS OR THUNDERSTORMS EACH DAY ACROSS THE FORECAST AREA.

.AVIATION.../18Z ISSUANCE/

VFR CONDITIONS WILL THEN PREVAIL ACROSS THE REGION THIS AFTERNOON
WITH NO SIGNIFICANT WINDS. A WEAK UPPER LEVEL DISTURBANCE WILL
SPREAD WDLY SCT -SHRA AND ISOLD -TSRA INTO THE NW MTNS...PRIMARILY
NORTH OF A KJAC-KCOD LINE...LATE THIS AFTERNOON AND EVENING WITH
THIS ACTIVITY SPREADING EAST AND A LITTLE SOUTH OVERNIGHT PRIMARILY
VCNTY AND NORTH OF KJAC-KWRL-KBYG LINE WITH CIGS FL120-150.

ANOTHER SYSTEM WILL MOVE IN FROM THE WEST DURING THE DAY FRIDAY WITH
ISOLATED TO WIDELY SCATTERED THUNDERSTORMS DEVELOPING AND SPREAD EAST
ACROSS THE CENTRAL AND NORTHERN PART OF THE DISTRICT...MAINLY FROM
A KJAC...KPNA...KLND...KCPR LINE. VFR CONDITIONS WILL PREVAIL ACROSS
MOST OF THE AREA WITH JUST TEMPORARY MVFR VSBY OF 3-5 MILES IN ANY
HEAVIER SHOWERS OR THUNDERSTORMS.

.FIRE WEATHER...

WEAKENING SHOWERS AND THUNDERSTORMS EXPECTED OVER THE AREA THIS
MORNING...WITH BUILDING DRY WEST TO NORTHWEST FLOW. A FEW SHOWERS
WILL BE POSSIBLE ACROSS THE EXTREME NORTHWEST DURING THE EVENING AND
OVERNIGHT HOURS...WITH DRY CONDITIONS OTHERWISE. AN APPROACHING WAVE
OF LOW PRESSURE WILL TURN THE FLOW TO THE SOUTHWEST LATE FRIDAY AND
INTO SATURDAY. AHEAD OF THE TROUGH AXIS...CONDITIONS ACROSS SOUTHERN
WYOMING COULD BECOME BREEZY AND DRY...RAISING SOME FIRE WEATHER
CONCERNS. THE THREAT WILL BE SHORT LIVED...WITH SHOWERS AND
THUNDERSTORMS ANTICIPATED ACROSS THE AREA BY SATURDAY AFTERNOON.

&&

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

&&

$$

SHORT TERM...BRANHAM
LONG TERM...KPL
AVIATION...SKRBAC
FIRE WEATHER...BRANHAM







000
FXUS63 KUNR 281703
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
1103 AM MDT THU AUG 28 2014

.UPDATE...
ISSUED AT 950 AM MDT THU AUG 28 2014

CURRENT SURFACE ANALYSIS SHOWS LOW PRESSURE OVER CENTRAL NEB...
WITH INVERTED TROF STRETCHING NORTHWARD ACROSS CENTRAL SD. HIGH
PRESSURE IS IN PLACE OVER THE CENTRAL ROCKIES. UPPER LEVEL
ANALYSIS SHOWS LOW NOW OVER WESTERN NEB...SLOWLY MOVING EAST-
SOUTHEAST. KUDX RADAR SHOWS ISOLATED TO SCATTERED SHOWERS FROM
CENTRAL SD TO FAR SOUTHWEST SD. THERE ARE A FEW LIGHTNING STRIKES
FROM TIME TO TIME WITH THE ACTIVITY OVER SOUTH CENTRAL SD. SKIES
RANGE FROM MOSTLY SUNNY OVER NORTHEAST WY TO MAINLY CLOUDY EAST OF
THE BLACK HILLS. TEMPS ARE IN THE 60S AND LOWER 70S WITH LIGHT AND
VARIABLE WINDS.

SHOWER AND THUNDERSTORM ACTIVITY WILL LINGER OVER MUCH OF
SOUTHWESTERN INTO CENTRAL SD INTO THE AFTERNOON...WITH A GRADUAL
EASTWARD SHIFT THROUGH THE AFTERNOON. MAY NEED TO ADD SOME POPS
FOR THE EARLY EVENING ACROSS SOUTH CENTRAL SD IF THE EASTWARD
TREND SLOWS DOWN A BIT. CLOUDS WILL ALSO GRADUALLY DECREASE FROM
WEST TO EAST ACROSS THE AREA THROUGH THE EVENING. HIGH TEMPS MIGHT
BE A BIT TOO HIGH IN SOME AREAS...BUT WILL SEE HOW QUICKLY THEY
RISE OVER THE NEXT 2 OR 3 HOURS BEFORE MAKING ANYMORE ADJUSTMENTS.
UPDATED FORECAST HAS BEEN SENT TO MAKE SHORT TERM CHANGES TO
POPS...CLOUD COVER...AND WIND.

&&

.SHORT TERM...TODAY THROUGH FRIDAY NIGHT
ISSUED AT 302 AM MDT THU AUG 28 2014

CURRENT SURFACE ANALYSIS SHOWS LOW PRESSURE OVER SASKATCHEWAN...WITH
A FRONTAL BOUNDARY EXTENDING THROUGH EASTERN MONTANA AND CENTRAL
WYOMING. UPPER LEVEL ANALYSIS SHOWS MAIN LOW PRESSURE AREA OVER NRN
COLORADO/SRN WYOMING WITH A TROF COVERING THE ROCKIES AND HIGH
PLAINS. LATEST RADAR IMAGERY SHOWS SHOWERS CONTINUING TO ROTATE AND
LIFT NORTH ACROSS THE SD PLAINS. A LITTLE EMBEDDED CONVECTION IS ALSO
OCCURRING IN SOUTH CENTRAL SD.

AS THE UPPER LOW MOVES SLOWLY EAST INTO THE CENTRAL HIGH PLAINS...
SHOWER/THUNDERSTORM ACTIVITY WILL QUICKLY DECREASE FROM WEST TO
EAST...WITH SHOWERS/STORMS CONTINUING ACROSS MUCH OF SOUTH CENTRAL
SOUTH DAKOTA. WITH A LOT OF LOW LEVEL MOISTURE AROUND...EXPECT
AREAS OF FOG TO LINGER INTO THE MORNING HOURS ACROSS MOST OF THE
WRN SD PLAINS. BY THIS AFTERNOON...DIURNAL HEATING AND LINGERING
INSTABILITY COULD PRODUCE A TERRAIN INDUCED SHOWER/STORM OVER THE
BLACK HILLS. THUS LEFT ISOLD POPS IN THE FORECAST. TEMPS TODAY
WILL BE WARMER WITH DECREASING CLOUDS...ESPECIALLY ACROSS THE NRN
AND WRN AREAS.

FOR TONIGHT...CLOUDS WILL CONTINUE TO GRADUALLY DECREASE FROM
NORTHWEST TO SOUTHEAST...WITH MOSTLY CLEAR SKIES OVERNIGHT. THIS
COMBINED WITH LIGHT WINDS AND SURFACE HIGH PRESSURE TO THE
WEST...DECIDED TO ADD SOME FOG FOR THE SD PLAINS. TEMPS WILL BE
NEAR NORMAL.

ON FRIDAY...SHORTWAVE TROF MOVES RAPIDLY ACROSS MT/ND PUSHING A WEAK
COOL FRONT INTO WESTERN SD. FORECAST SOUNDINGS SUPPORT 250-500J/KG
MLCAPE...WITH SUFFICIENT LOW LEVEL MOISTURE/CAPE/SHEAR FOR STORMS.
MOST OF THE 500-700MB MOISTURE REMAINS NORTH OF THE CWA...HOWEVER
COULD SEE SCATTERED STORMS WITH AN ISOLATED STRONG STORM ACROSS
NORTHWEST HALF OF CWA. TEMPERATURES ON FRIDAY WILL BE A LITTLE
COOLER THAN TODAY IN THE NW...BUT MOST AREAS WILL SEE WARMER
TEMPERATURES.

&&

.LONG TERM...SATURDAY THROUGH WEDNESDAY
ISSUED AT 302 AM MDT THU AUG 28 2014

PROGRESSIVE NORTHERN STREAM FLOW WILL CONTINUE THROUGH THE PERIOD
WITH A LONG WAVE UPPER LEVEL TROUGH ON TRACK TO ADVECT THROUGH THE
REGION SAT-SUN...WITH A WEAKER SHORTWAVE IMPULSE POSSIBLE MONDAY.
TROUGH RELOADING OVER THE NE PAC TUE-WED FAVORED IN ECMWF/GFS
SOLUTIONS...WHICH WOULD SUPPORT MEAN RIDGING OVER THE NORTHERN
PLAINS WITH DRY AND WARMER CONDITIONS. MAIN FORECAST TREND IS A
QUICKER ARRIVAL OF THE EXPECTED LONG WAVE TROUGH SAT...WITH PRECIP
CHANCES INCREASING SAT AFTERNOON WESTERN THIRD. OTHERWISE...THE
REMAINDER OF THE FORECAST IS ON TRACK ATTM.

UPPER LEVEL TROUGH WILL PUSH OUT OF THE NE PAC AND INTO THE NORTHERN
PLAINS...SUPPORTING INCREASING LSA SAT THROUGH SUNDAY. LEE SIDE SFC
TROUGH WILL WILL INTERACT WITH THE APPROACHING UPPER WAVE SUPPORTING
A FOCUS FOR SHRA/TS ACTIVITY OVER THE WESTERN FA BY SAT AFTERNOON.
LL SE FLOW AHEAD OF THIS SYSTEM WITH MOIST UPPER LEVEL SW FLOW WILL
SUPPORT INCREASING PW OVER THE REGION...WITH PLENTY OF MOISTURE
BEING AVAILABLE WITH THIS SYSTEM. SOME MODEL INDICATION FOR
SUFFICIENT DEEP LAYER SHEAR AND CAPE OVER THE FAR NW ZONES...ESP NW
SD BY SAT EVENING...SUPPORTING A POSSIBLE SEVERE THREAT THERE.
SOMETHING TO WATCH. HAVE ADJUSTED POPS UP SAT AFTERNOON AND SAT
EVENING...WITH THE PRIMARY SOUTHERN PERIPHERY IMPULSE EXPECTED TO
SHIFT NE ACROSS THE NW FA. TRAILING SFC TROUGH WITH SUFFICIENT LSA
SHOULD SUPPORT A GOOD CHANCE OF SHRA/TS NW THIRD...WITH MORE
SCT/ISOLD ACTIVITY ACROSS THE REMAINDER OF THE FA. UPPER LEVEL COLD
POOL WILL SUPPORT STEEP LL LAPSE RATES OVER THE FA SUNDAY WITH
RESIDUAL LL MOISTURE IN PLACE. DIURNAL HEATING COUPLED WITH BH/NE WY
TERRAIN INFLUENCES SHOULD SUPPORT SCT TO ISOLD SHRA/TS SW HALF OF
THE FA. BUMPED POPS UP OVER THE BH. OTHERWISE...ONE MORE WEAKER
WESTERLY FLOW IMPULSE STILL INDICATED IN FORECAST MODELS
MONDAY...POSSIBLY SUPPORTING A FEW SHRA/TS...ALTHOUGH UPPER LEVEL
SUPPORT LOOKS MARGINAL ATTM...ESP WITH DRY PROFILES. DRY CONDS
EXPECTED TUE-WED WITH MEAN DEEP LAYER RIDGING.

SEASONAL TEMPS EXPECTED IN MOST OF THE PERIOD...WITH BELOW NORMAL
TEMPS /5-10 DEGREES/ EXPECTED SUNDAY THROUGH MONDAY...ESP NW AREAS.
THE WARMEST DAY IN PERIOD LOOKS TO BE SAT...ESP ON THE SD PLAINS.
ALTHOUGH THERE IS SOME INDICATION FOR WARM CONDITIONS NEXT WED GIVEN
SW WAA FLOW AHEAD OF THE NEXT POTENTIAL EJECTING NE PAC UPPER
TROUGH.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY)
ISSUED AT 1059 AM MDT THU AUG 28 2014

-SHRA/ISOLATED -TSRA EAST OF A LINE FROM KMGB TO KCUT WILL
CONTINUE TO SLIDE EAST THIS AFTERNOON...EXITING THE AREA
COMPLETELY EARLY THIS EVENING. AREAS IFR CIGS/VSBYS ASSOCIATED
WITH THE PRECIPITATION AND ST/BR WILL SHIFT EAST ALSO. BEHIND
THESE FEATURES...VFR CONDITIONS ARE EXPECTED THROUGH FRIDAY
MORNING. THE EXCEPTION WILL BE ON THE SD PLAINS LATER TONIGHT
WHERE LOCAL MVFR VSBYS DUE TO BR MAY OCCUR.

&&

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

$$

UPDATE...26
SHORT TERM...MLS
LONG TERM...JC
AVIATION...HELGESON





000
FXUS63 KUNR 281703
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
1103 AM MDT THU AUG 28 2014

.UPDATE...
ISSUED AT 950 AM MDT THU AUG 28 2014

CURRENT SURFACE ANALYSIS SHOWS LOW PRESSURE OVER CENTRAL NEB...
WITH INVERTED TROF STRETCHING NORTHWARD ACROSS CENTRAL SD. HIGH
PRESSURE IS IN PLACE OVER THE CENTRAL ROCKIES. UPPER LEVEL
ANALYSIS SHOWS LOW NOW OVER WESTERN NEB...SLOWLY MOVING EAST-
SOUTHEAST. KUDX RADAR SHOWS ISOLATED TO SCATTERED SHOWERS FROM
CENTRAL SD TO FAR SOUTHWEST SD. THERE ARE A FEW LIGHTNING STRIKES
FROM TIME TO TIME WITH THE ACTIVITY OVER SOUTH CENTRAL SD. SKIES
RANGE FROM MOSTLY SUNNY OVER NORTHEAST WY TO MAINLY CLOUDY EAST OF
THE BLACK HILLS. TEMPS ARE IN THE 60S AND LOWER 70S WITH LIGHT AND
VARIABLE WINDS.

SHOWER AND THUNDERSTORM ACTIVITY WILL LINGER OVER MUCH OF
SOUTHWESTERN INTO CENTRAL SD INTO THE AFTERNOON...WITH A GRADUAL
EASTWARD SHIFT THROUGH THE AFTERNOON. MAY NEED TO ADD SOME POPS
FOR THE EARLY EVENING ACROSS SOUTH CENTRAL SD IF THE EASTWARD
TREND SLOWS DOWN A BIT. CLOUDS WILL ALSO GRADUALLY DECREASE FROM
WEST TO EAST ACROSS THE AREA THROUGH THE EVENING. HIGH TEMPS MIGHT
BE A BIT TOO HIGH IN SOME AREAS...BUT WILL SEE HOW QUICKLY THEY
RISE OVER THE NEXT 2 OR 3 HOURS BEFORE MAKING ANYMORE ADJUSTMENTS.
UPDATED FORECAST HAS BEEN SENT TO MAKE SHORT TERM CHANGES TO
POPS...CLOUD COVER...AND WIND.

&&

.SHORT TERM...TODAY THROUGH FRIDAY NIGHT
ISSUED AT 302 AM MDT THU AUG 28 2014

CURRENT SURFACE ANALYSIS SHOWS LOW PRESSURE OVER SASKATCHEWAN...WITH
A FRONTAL BOUNDARY EXTENDING THROUGH EASTERN MONTANA AND CENTRAL
WYOMING. UPPER LEVEL ANALYSIS SHOWS MAIN LOW PRESSURE AREA OVER NRN
COLORADO/SRN WYOMING WITH A TROF COVERING THE ROCKIES AND HIGH
PLAINS. LATEST RADAR IMAGERY SHOWS SHOWERS CONTINUING TO ROTATE AND
LIFT NORTH ACROSS THE SD PLAINS. A LITTLE EMBEDDED CONVECTION IS ALSO
OCCURRING IN SOUTH CENTRAL SD.

AS THE UPPER LOW MOVES SLOWLY EAST INTO THE CENTRAL HIGH PLAINS...
SHOWER/THUNDERSTORM ACTIVITY WILL QUICKLY DECREASE FROM WEST TO
EAST...WITH SHOWERS/STORMS CONTINUING ACROSS MUCH OF SOUTH CENTRAL
SOUTH DAKOTA. WITH A LOT OF LOW LEVEL MOISTURE AROUND...EXPECT
AREAS OF FOG TO LINGER INTO THE MORNING HOURS ACROSS MOST OF THE
WRN SD PLAINS. BY THIS AFTERNOON...DIURNAL HEATING AND LINGERING
INSTABILITY COULD PRODUCE A TERRAIN INDUCED SHOWER/STORM OVER THE
BLACK HILLS. THUS LEFT ISOLD POPS IN THE FORECAST. TEMPS TODAY
WILL BE WARMER WITH DECREASING CLOUDS...ESPECIALLY ACROSS THE NRN
AND WRN AREAS.

FOR TONIGHT...CLOUDS WILL CONTINUE TO GRADUALLY DECREASE FROM
NORTHWEST TO SOUTHEAST...WITH MOSTLY CLEAR SKIES OVERNIGHT. THIS
COMBINED WITH LIGHT WINDS AND SURFACE HIGH PRESSURE TO THE
WEST...DECIDED TO ADD SOME FOG FOR THE SD PLAINS. TEMPS WILL BE
NEAR NORMAL.

ON FRIDAY...SHORTWAVE TROF MOVES RAPIDLY ACROSS MT/ND PUSHING A WEAK
COOL FRONT INTO WESTERN SD. FORECAST SOUNDINGS SUPPORT 250-500J/KG
MLCAPE...WITH SUFFICIENT LOW LEVEL MOISTURE/CAPE/SHEAR FOR STORMS.
MOST OF THE 500-700MB MOISTURE REMAINS NORTH OF THE CWA...HOWEVER
COULD SEE SCATTERED STORMS WITH AN ISOLATED STRONG STORM ACROSS
NORTHWEST HALF OF CWA. TEMPERATURES ON FRIDAY WILL BE A LITTLE
COOLER THAN TODAY IN THE NW...BUT MOST AREAS WILL SEE WARMER
TEMPERATURES.

&&

.LONG TERM...SATURDAY THROUGH WEDNESDAY
ISSUED AT 302 AM MDT THU AUG 28 2014

PROGRESSIVE NORTHERN STREAM FLOW WILL CONTINUE THROUGH THE PERIOD
WITH A LONG WAVE UPPER LEVEL TROUGH ON TRACK TO ADVECT THROUGH THE
REGION SAT-SUN...WITH A WEAKER SHORTWAVE IMPULSE POSSIBLE MONDAY.
TROUGH RELOADING OVER THE NE PAC TUE-WED FAVORED IN ECMWF/GFS
SOLUTIONS...WHICH WOULD SUPPORT MEAN RIDGING OVER THE NORTHERN
PLAINS WITH DRY AND WARMER CONDITIONS. MAIN FORECAST TREND IS A
QUICKER ARRIVAL OF THE EXPECTED LONG WAVE TROUGH SAT...WITH PRECIP
CHANCES INCREASING SAT AFTERNOON WESTERN THIRD. OTHERWISE...THE
REMAINDER OF THE FORECAST IS ON TRACK ATTM.

UPPER LEVEL TROUGH WILL PUSH OUT OF THE NE PAC AND INTO THE NORTHERN
PLAINS...SUPPORTING INCREASING LSA SAT THROUGH SUNDAY. LEE SIDE SFC
TROUGH WILL WILL INTERACT WITH THE APPROACHING UPPER WAVE SUPPORTING
A FOCUS FOR SHRA/TS ACTIVITY OVER THE WESTERN FA BY SAT AFTERNOON.
LL SE FLOW AHEAD OF THIS SYSTEM WITH MOIST UPPER LEVEL SW FLOW WILL
SUPPORT INCREASING PW OVER THE REGION...WITH PLENTY OF MOISTURE
BEING AVAILABLE WITH THIS SYSTEM. SOME MODEL INDICATION FOR
SUFFICIENT DEEP LAYER SHEAR AND CAPE OVER THE FAR NW ZONES...ESP NW
SD BY SAT EVENING...SUPPORTING A POSSIBLE SEVERE THREAT THERE.
SOMETHING TO WATCH. HAVE ADJUSTED POPS UP SAT AFTERNOON AND SAT
EVENING...WITH THE PRIMARY SOUTHERN PERIPHERY IMPULSE EXPECTED TO
SHIFT NE ACROSS THE NW FA. TRAILING SFC TROUGH WITH SUFFICIENT LSA
SHOULD SUPPORT A GOOD CHANCE OF SHRA/TS NW THIRD...WITH MORE
SCT/ISOLD ACTIVITY ACROSS THE REMAINDER OF THE FA. UPPER LEVEL COLD
POOL WILL SUPPORT STEEP LL LAPSE RATES OVER THE FA SUNDAY WITH
RESIDUAL LL MOISTURE IN PLACE. DIURNAL HEATING COUPLED WITH BH/NE WY
TERRAIN INFLUENCES SHOULD SUPPORT SCT TO ISOLD SHRA/TS SW HALF OF
THE FA. BUMPED POPS UP OVER THE BH. OTHERWISE...ONE MORE WEAKER
WESTERLY FLOW IMPULSE STILL INDICATED IN FORECAST MODELS
MONDAY...POSSIBLY SUPPORTING A FEW SHRA/TS...ALTHOUGH UPPER LEVEL
SUPPORT LOOKS MARGINAL ATTM...ESP WITH DRY PROFILES. DRY CONDS
EXPECTED TUE-WED WITH MEAN DEEP LAYER RIDGING.

SEASONAL TEMPS EXPECTED IN MOST OF THE PERIOD...WITH BELOW NORMAL
TEMPS /5-10 DEGREES/ EXPECTED SUNDAY THROUGH MONDAY...ESP NW AREAS.
THE WARMEST DAY IN PERIOD LOOKS TO BE SAT...ESP ON THE SD PLAINS.
ALTHOUGH THERE IS SOME INDICATION FOR WARM CONDITIONS NEXT WED GIVEN
SW WAA FLOW AHEAD OF THE NEXT POTENTIAL EJECTING NE PAC UPPER
TROUGH.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY)
ISSUED AT 1059 AM MDT THU AUG 28 2014

-SHRA/ISOLATED -TSRA EAST OF A LINE FROM KMGB TO KCUT WILL
CONTINUE TO SLIDE EAST THIS AFTERNOON...EXITING THE AREA
COMPLETELY EARLY THIS EVENING. AREAS IFR CIGS/VSBYS ASSOCIATED
WITH THE PRECIPITATION AND ST/BR WILL SHIFT EAST ALSO. BEHIND
THESE FEATURES...VFR CONDITIONS ARE EXPECTED THROUGH FRIDAY
MORNING. THE EXCEPTION WILL BE ON THE SD PLAINS LATER TONIGHT
WHERE LOCAL MVFR VSBYS DUE TO BR MAY OCCUR.

&&

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

$$

UPDATE...26
SHORT TERM...MLS
LONG TERM...JC
AVIATION...HELGESON




000
FXUS65 KCYS 281659
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
1059 AM MDT THU AUG 28 2014

.UPDATE...
ISSUED AT 1039 AM MDT THU AUG 28 2014

A VIGOROUS MIDLVL SHORTWAVE CONTINUES TO ROTATE ACROSS THE WESTERN
NE PANHANDLE THIS MORNING. WRAP-AROUND MOISTURE ON THE BACK SIDE
OF THIS SYSTEM IS CONTRIBUTING TO WIDESPREAD SHOWERS OR STRATIFORM
RAIN ALONG A LINE FROM CENTENNIAL TO WHEATLAND. HAVE RECENTLY SEEN
SOME HIGHER ECHOS IN CENTRAL PLATTE COUNTY...AS WELL AS SOME AREAS
ALONG THE WEST EDGE OF THE LARAMIE RANGE. 1-2 INCHES OF RAIN ON
WED MORNING AND AFTN LENDS SOME CONCERN TO FLOODING POTENTIAL IF
RATES ARE HIGH ENOUGH AND/OR WE SEE MORE TRAINING. FFMP DATA ALSO
SHOWS AREAS NORTHEAST OF BOSLER HAVE ALREADY RECEIVED CLOSE TO 2
INCHES OF RAIN TODAY. WILL CONTINUE TO MONITOR CLOSELY THROUGH
THE DAY FOR POSSIBLE STATEMENTS...BUT CURRENT WEBCAMS SUGGEST THE
GROUND IS ABSORBING THINGS WELL. ONGOING CLOUDS AND RAIN WILL MAKE
IT TOUGH TO REACH FCST HIGHS...SO IN A RECENT UPDATE HAVE CUT BACK
ON TEMPS BY 5-10 DEGREES WHERE MOST OF THE PRECIP IS OCCURRING PER
THE LATEST KCYS RADAR LOOP. ALSO BUMPED UP POPS INTO THE LIKELY
CATEGORY FOR FAR SOUTHEAST WY AND WESTERN NE...EXPANDING EASTWARD
WITH TIME.

&&

.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 425 AM MDT THU AUG 28 2014

PREDAWN WATER VAPOR IMAGERY SHOWED THE UPPER LOW OVER SOUTHERN WY/NORTHERN
CO. AT THE SURFACE...A FRONT EXTENDED FROM THE MID-ATLANTIC REGION ACROSS
THE TN VALLEY TO A LOW ALONG THE CENTRAL NE/KS BORDER THEN SOUTHWEST
TO ANOTHER LOW IN SOUTHEAST CO. A LARGE CLUSTER OF STRONG CONVECTION
DEVELOPED ALONG AND JUST NORTH OF THE FRONT OVER SOUTH CENTRAL/SOUTHEAST
NE. LIGHT SHOWERS WERE DEVELOPING AND MOVING SOUTHWEST FROM EAST CENTRAL
TO SOUTH CENTRAL WY.

THE 00Z CONSENSUS MODEL GUIDANCE WEAKENS THE UPPER LOW TO AN OPEN WAVE
THIS MORNING OVER THE HIGH PLAINS...PROGRESSING SLOWLY EAST INTO THE
CENTRAL GREAT PLAINS FRIDAY. CONVECTIVE COVERAGE TODAY WILL BE LESS
THAN THE PAST FEW DAYS WITH THE RISK FOR HEAVY RAINFALL FROM THE CENTRAL
PLAINS TO THE UPPER MS VALLEY. WRAPAROUND MOISTURE OVER NORTHERN AND
WESTERN PORTIONS OF THE CWA THIS MORNING WILL GRADUALLY SLIDE EAST
THIS AFTERNOON AND EARLY EVENING. THERE WILL BE ENOUGH INSTABILITY FROM
DAYTIME HEATING FOR SCATTERED SHOWERS/TSTORMS THIS AFTERNOON...ESPECIALLY
SOUTH OF A RAWLINS WY TO ALLIANCE NE LINE. HIGH TEMPERATURES TODAY WILL
BE SLIGHTLY WARMER WITH 70S FOR LOWER ELEVATIONS.

A FEW LINGERING SHOWERS OR TSTORMS OVER THE EXTREME SOUTHERN NE PANHANDLE
EARLY THIS EVENING. OTHERWISE...SUBSIDENCE AND DRIER MORE STABLE AIRMASS
WILL SPREAD WEST TO EAST WITH THE APPROACH AND PASSAGE OF A SHORTWAVE
RIDGE.

A WEAK SHORTWAVE OVER THE NORTHERN ROCKIES EARLY FRIDAY MORNING MAKES
A BEELINE FOR THE NORTHERN HIGH PLAINS FRIDAY AFTERNOON. MOISTURE WILL
BE LIMITED WITH MARGINAL INSTABILITY FOR ISOLATED AFTERNOON TSTORMS
OVER THE MOUNTAINS AND NEARBY PLAINS OF SOUTHEAST WY. HIGH TEMPERATURES
WILL WARM INTO THE 80S EAST OF THE LARAMIE RANGE...WITH 60S AND 70S
WEST. EXPECT TRANQUIL CONDITIONS FRIDAY NIGHT WITH THE PASSAGE OF
ANOTHER SHORTWAVE RIDGE.

LATEST MODELS CONTINUE TO DEPICT A MORE SIGNIFICANT UPPER TROUGH TAKING
SHAPE OVER THE GREAT BASIN AND PACIFIC NORTHWEST SATURDAY. A RATHER
STRONG PACIFIC COLD FRONT WILL BE MOVING THROUGH NORTHERN AND WESTERN
WY DURING THE AFTERNOON. 700MB WINDS INCREASE TO 35 KT FROM THE WEST
AND SOUTHWEST. PACIFIC MOISTURE WILL ALSO INCREASE BY LATE AFTERNOON
WITH WIDELY SCATTERED SHOWERS/TSTORMS DEVELOPING ALONG AND WEST OF A
CHADRON NE TO CHEYENNE WY LINE. A TIGHTER SURFACE PRESSURE GRADIENT
WILL CREATE RATHER BREEZY WEST TO SOUTHWEST WINDS. IT WILL BE A WARM
AFTERNOON WITH HIGHS IN THE 80S TO LOWER 90S FOR THE PLAINS...WITH 60S
AND 70S WEST.

.LONG TERM...(SATURDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 350 AM MDT THU AUG 28 2014

MEDIUM AND LONG RANGE MODELS IN GOOD AGREEMENT INTO EARLY NEXT WEEK.
THE MAIN FORECAST CONCERN WILL BE A BROAD UPPER LEVEL TROUGH AND
ASSOCIATED COLD FRONT FOR LATER THIS WEEKEND. THE COLD FRONT APPEARS
TO BE RATHER STRONG FOR THIS TIME OF THE YEAR...WITH GUSTY WINDS
POSSIBLE ALONG WITH RAIN SHOWERS/TSTORMS OVER MOST OF THE AREA.
CANNOT RULE OUT SOME SNOWFALL ACROSS THE HIGH MOUNTAINS AS THIS FRONT
MOVES ACROSS THE AREA SATURDAY NIGHT AND INTO EARLY SUNDAY. MODELS
IN GOOD AGREEMENT WITH THE TIMING...ALTHOUGH THE GFS IS NOTICEABLY
MORE PROGRESSIVE AND DRIER. PREFER THE ECMWF AND GEM AT THIS TIME
SINCE BOTH THESE MODELS DID BETTER WITH THIS LAST STORM SYSTEM 3
DAYS OUT IN TERMS OF TIMING AND EVOLUTION. INCREASED POP ABOVE 30
PERCENT ACROSS MOST OF THE FORECAST AREA FOR SCATTERED SHOWERS AND
ISOLATED TSTORMS. INCREASED WINDS AS WELL...ALTHOUGH MODEL
SOUNDINGS ARE SUGGESTING SUSTAINED WESTERLY WINDS BETWEEN 20 TO 30
MPH AND GUSTS AROUND 40 MPH. DID NOT INCREASE WINDS QUITE THAT
HIGH SINCE THE ECMWF SHOWS MUCH LOWER WIND SPEEDS SUNDAY AFTERNOON.
TEMPERATURES WILL REMAIN ON THE COOL SIDE AND GENERALLY IN THE
UPPER 60S TO UPPER 70S...WARMEST ACROSS THE NEBRASKA PANHANDLE.

MODELS THEN INDICATE A DRYING TREND FOR NEXT WEEK AS THE SOUTHWESTERN
MONSOON MAY BE ENDING...WHICH IS TYPICAL IN THE LATE SUMMER. MODELS
AND ENSEMBLES ALSO SHOW WHAT APPEARS TO BE A TRANSITIONAL PERIOD IN
THE PATTERN...AS THE POLAR JET STREAM BECOMES MORE DEFINED BY DAY
6 AND 7 NEAR THE CANADIAN BORDER. THIS WILL RESULT IN QUASI-ZONAL
FLOW OVER THE WESTERN TWO THIRDS OF THE UNITED STATES. HOWEVER...THE
ECMWF AND GEM DO SHOW AN UPPER LEVEL DISTURBANCE MOVING SOUTHEAST
ACROSS THE HIGH PLAINS LATE ON MONDAY...SO KEPT LOW POP OVER EAST
CENTRAL WYOMING AND NORTHWEST NEBRASKA. OTHERWISE...TEMPERATURES
WILL GRADUALLY INCREASE TO AROUND NORMAL FOR THIS TIME OF THE YEAR
WITH HIGHS AROUND 80 ALONG AND WEST OF THE LARAMIE RANGE AND RANGING
FROM THE LOW 80S TO THE LOW 90S ACROSS THE HIGH PLAINS EAST OF THE
LARAMIE RANGE BY WEDNESDAY AFTERNOON.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH LATE TONIGHT)
ISSUED AT 350 AM MDT THU AUG 28 2014

LOW CIGS WILL PERSIST EARLY THIS MORNING ACROSS MAINLY THE WESTERN
NEBRASKA PANHANDLE TERMINALS. FOG IS UNLIKELY AT THIS TIME DUE TO
CLOUD COVER. FOG AND LOW CIGS WILL LIFT BY MID MORNING WITH VFR
PREVAILING THROUGH NOON. THE NEXT BAND OF SHOWERS WILL DEVELOP AND
GROW IN COVERAGE EARLY THIS MORNING FROM RAWLINS TO LARAMIE. THIS
BAND WILL INTENSIFY AS THE UPPER LEVEL LOW GRADUALLY DRIFTS ACROSS
NORTHEAST COLORADO. THIS BAND OF RAINFALL AND EMBEDDED TSTORMS
WILL RESULT IN LOCALIZED MVFR CONDITIONS SOUTHEAST OF A KLAR TO
KCDR LINE BY LATE THIS MORNING AND INTO THIS AFTERNOON.


&&

.FIRE WEATHER...
ISSUED AT 255 AM MDT THU AUG 28 2014

THE UPPER LOW PRESSURE SYSTEM RESPONSIBLE FOR THE INCLEMENT WEATHER
THE PAST FEW DAYS WILL MOVE EAST FROM THE CENTRAL ROCKIES TODAY TO
THE CENTRAL GREAT PLAINS FRIDAY. A MORE SCATTERED COVERAGE OF SHOWERS
AND THUNDERSTORMS IS EXPECTED TODAY. MAINLY DRIER AND WARMER CONDITIONS
ARE FORECAST FOR FRIDAY WITH JUST A SLIGHT CHANCE OF AFTERNOON
THUNDERSTORMS OVER THE MOUNTAINS AND PORTIONS OF EAST CENTRAL WYOMING
WITH THE PASSAGE OF A WEAK UPPER LEVEL DISTURBANCE. ISOLATED TO
SCATTERED MAINLY AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS ARE
FORECAST SATURDAY AND SUNDAY AS A MORE SIGNIFICANT UPPER TROUGH AND
COLD FRONT AFFECT THE DISTRICTS. WARM TEMPERATURES SATURDAY WILL TURN
COOLER SUNDAY FOLLOWING THE COLD FRONTAL PASSAGE. THE TIGHT PRESSURE
GRADIENT WILL RESULT IN GUSTY WESTERLY WINDS THIS WEEKEND.

&&

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

$$

UPDATE...HAMMER
SHORT TERM...JAMSKI
LONG TERM...TJT
AVIATION...TJT
FIRE WEATHER...JAMSKI







000
FXUS65 KCYS 281659
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
1059 AM MDT THU AUG 28 2014

.UPDATE...
ISSUED AT 1039 AM MDT THU AUG 28 2014

A VIGOROUS MIDLVL SHORTWAVE CONTINUES TO ROTATE ACROSS THE WESTERN
NE PANHANDLE THIS MORNING. WRAP-AROUND MOISTURE ON THE BACK SIDE
OF THIS SYSTEM IS CONTRIBUTING TO WIDESPREAD SHOWERS OR STRATIFORM
RAIN ALONG A LINE FROM CENTENNIAL TO WHEATLAND. HAVE RECENTLY SEEN
SOME HIGHER ECHOS IN CENTRAL PLATTE COUNTY...AS WELL AS SOME AREAS
ALONG THE WEST EDGE OF THE LARAMIE RANGE. 1-2 INCHES OF RAIN ON
WED MORNING AND AFTN LENDS SOME CONCERN TO FLOODING POTENTIAL IF
RATES ARE HIGH ENOUGH AND/OR WE SEE MORE TRAINING. FFMP DATA ALSO
SHOWS AREAS NORTHEAST OF BOSLER HAVE ALREADY RECEIVED CLOSE TO 2
INCHES OF RAIN TODAY. WILL CONTINUE TO MONITOR CLOSELY THROUGH
THE DAY FOR POSSIBLE STATEMENTS...BUT CURRENT WEBCAMS SUGGEST THE
GROUND IS ABSORBING THINGS WELL. ONGOING CLOUDS AND RAIN WILL MAKE
IT TOUGH TO REACH FCST HIGHS...SO IN A RECENT UPDATE HAVE CUT BACK
ON TEMPS BY 5-10 DEGREES WHERE MOST OF THE PRECIP IS OCCURRING PER
THE LATEST KCYS RADAR LOOP. ALSO BUMPED UP POPS INTO THE LIKELY
CATEGORY FOR FAR SOUTHEAST WY AND WESTERN NE...EXPANDING EASTWARD
WITH TIME.

&&

.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 425 AM MDT THU AUG 28 2014

PREDAWN WATER VAPOR IMAGERY SHOWED THE UPPER LOW OVER SOUTHERN WY/NORTHERN
CO. AT THE SURFACE...A FRONT EXTENDED FROM THE MID-ATLANTIC REGION ACROSS
THE TN VALLEY TO A LOW ALONG THE CENTRAL NE/KS BORDER THEN SOUTHWEST
TO ANOTHER LOW IN SOUTHEAST CO. A LARGE CLUSTER OF STRONG CONVECTION
DEVELOPED ALONG AND JUST NORTH OF THE FRONT OVER SOUTH CENTRAL/SOUTHEAST
NE. LIGHT SHOWERS WERE DEVELOPING AND MOVING SOUTHWEST FROM EAST CENTRAL
TO SOUTH CENTRAL WY.

THE 00Z CONSENSUS MODEL GUIDANCE WEAKENS THE UPPER LOW TO AN OPEN WAVE
THIS MORNING OVER THE HIGH PLAINS...PROGRESSING SLOWLY EAST INTO THE
CENTRAL GREAT PLAINS FRIDAY. CONVECTIVE COVERAGE TODAY WILL BE LESS
THAN THE PAST FEW DAYS WITH THE RISK FOR HEAVY RAINFALL FROM THE CENTRAL
PLAINS TO THE UPPER MS VALLEY. WRAPAROUND MOISTURE OVER NORTHERN AND
WESTERN PORTIONS OF THE CWA THIS MORNING WILL GRADUALLY SLIDE EAST
THIS AFTERNOON AND EARLY EVENING. THERE WILL BE ENOUGH INSTABILITY FROM
DAYTIME HEATING FOR SCATTERED SHOWERS/TSTORMS THIS AFTERNOON...ESPECIALLY
SOUTH OF A RAWLINS WY TO ALLIANCE NE LINE. HIGH TEMPERATURES TODAY WILL
BE SLIGHTLY WARMER WITH 70S FOR LOWER ELEVATIONS.

A FEW LINGERING SHOWERS OR TSTORMS OVER THE EXTREME SOUTHERN NE PANHANDLE
EARLY THIS EVENING. OTHERWISE...SUBSIDENCE AND DRIER MORE STABLE AIRMASS
WILL SPREAD WEST TO EAST WITH THE APPROACH AND PASSAGE OF A SHORTWAVE
RIDGE.

A WEAK SHORTWAVE OVER THE NORTHERN ROCKIES EARLY FRIDAY MORNING MAKES
A BEELINE FOR THE NORTHERN HIGH PLAINS FRIDAY AFTERNOON. MOISTURE WILL
BE LIMITED WITH MARGINAL INSTABILITY FOR ISOLATED AFTERNOON TSTORMS
OVER THE MOUNTAINS AND NEARBY PLAINS OF SOUTHEAST WY. HIGH TEMPERATURES
WILL WARM INTO THE 80S EAST OF THE LARAMIE RANGE...WITH 60S AND 70S
WEST. EXPECT TRANQUIL CONDITIONS FRIDAY NIGHT WITH THE PASSAGE OF
ANOTHER SHORTWAVE RIDGE.

LATEST MODELS CONTINUE TO DEPICT A MORE SIGNIFICANT UPPER TROUGH TAKING
SHAPE OVER THE GREAT BASIN AND PACIFIC NORTHWEST SATURDAY. A RATHER
STRONG PACIFIC COLD FRONT WILL BE MOVING THROUGH NORTHERN AND WESTERN
WY DURING THE AFTERNOON. 700MB WINDS INCREASE TO 35 KT FROM THE WEST
AND SOUTHWEST. PACIFIC MOISTURE WILL ALSO INCREASE BY LATE AFTERNOON
WITH WIDELY SCATTERED SHOWERS/TSTORMS DEVELOPING ALONG AND WEST OF A
CHADRON NE TO CHEYENNE WY LINE. A TIGHTER SURFACE PRESSURE GRADIENT
WILL CREATE RATHER BREEZY WEST TO SOUTHWEST WINDS. IT WILL BE A WARM
AFTERNOON WITH HIGHS IN THE 80S TO LOWER 90S FOR THE PLAINS...WITH 60S
AND 70S WEST.

.LONG TERM...(SATURDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 350 AM MDT THU AUG 28 2014

MEDIUM AND LONG RANGE MODELS IN GOOD AGREEMENT INTO EARLY NEXT WEEK.
THE MAIN FORECAST CONCERN WILL BE A BROAD UPPER LEVEL TROUGH AND
ASSOCIATED COLD FRONT FOR LATER THIS WEEKEND. THE COLD FRONT APPEARS
TO BE RATHER STRONG FOR THIS TIME OF THE YEAR...WITH GUSTY WINDS
POSSIBLE ALONG WITH RAIN SHOWERS/TSTORMS OVER MOST OF THE AREA.
CANNOT RULE OUT SOME SNOWFALL ACROSS THE HIGH MOUNTAINS AS THIS FRONT
MOVES ACROSS THE AREA SATURDAY NIGHT AND INTO EARLY SUNDAY. MODELS
IN GOOD AGREEMENT WITH THE TIMING...ALTHOUGH THE GFS IS NOTICEABLY
MORE PROGRESSIVE AND DRIER. PREFER THE ECMWF AND GEM AT THIS TIME
SINCE BOTH THESE MODELS DID BETTER WITH THIS LAST STORM SYSTEM 3
DAYS OUT IN TERMS OF TIMING AND EVOLUTION. INCREASED POP ABOVE 30
PERCENT ACROSS MOST OF THE FORECAST AREA FOR SCATTERED SHOWERS AND
ISOLATED TSTORMS. INCREASED WINDS AS WELL...ALTHOUGH MODEL
SOUNDINGS ARE SUGGESTING SUSTAINED WESTERLY WINDS BETWEEN 20 TO 30
MPH AND GUSTS AROUND 40 MPH. DID NOT INCREASE WINDS QUITE THAT
HIGH SINCE THE ECMWF SHOWS MUCH LOWER WIND SPEEDS SUNDAY AFTERNOON.
TEMPERATURES WILL REMAIN ON THE COOL SIDE AND GENERALLY IN THE
UPPER 60S TO UPPER 70S...WARMEST ACROSS THE NEBRASKA PANHANDLE.

MODELS THEN INDICATE A DRYING TREND FOR NEXT WEEK AS THE SOUTHWESTERN
MONSOON MAY BE ENDING...WHICH IS TYPICAL IN THE LATE SUMMER. MODELS
AND ENSEMBLES ALSO SHOW WHAT APPEARS TO BE A TRANSITIONAL PERIOD IN
THE PATTERN...AS THE POLAR JET STREAM BECOMES MORE DEFINED BY DAY
6 AND 7 NEAR THE CANADIAN BORDER. THIS WILL RESULT IN QUASI-ZONAL
FLOW OVER THE WESTERN TWO THIRDS OF THE UNITED STATES. HOWEVER...THE
ECMWF AND GEM DO SHOW AN UPPER LEVEL DISTURBANCE MOVING SOUTHEAST
ACROSS THE HIGH PLAINS LATE ON MONDAY...SO KEPT LOW POP OVER EAST
CENTRAL WYOMING AND NORTHWEST NEBRASKA. OTHERWISE...TEMPERATURES
WILL GRADUALLY INCREASE TO AROUND NORMAL FOR THIS TIME OF THE YEAR
WITH HIGHS AROUND 80 ALONG AND WEST OF THE LARAMIE RANGE AND RANGING
FROM THE LOW 80S TO THE LOW 90S ACROSS THE HIGH PLAINS EAST OF THE
LARAMIE RANGE BY WEDNESDAY AFTERNOON.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH LATE TONIGHT)
ISSUED AT 350 AM MDT THU AUG 28 2014

LOW CIGS WILL PERSIST EARLY THIS MORNING ACROSS MAINLY THE WESTERN
NEBRASKA PANHANDLE TERMINALS. FOG IS UNLIKELY AT THIS TIME DUE TO
CLOUD COVER. FOG AND LOW CIGS WILL LIFT BY MID MORNING WITH VFR
PREVAILING THROUGH NOON. THE NEXT BAND OF SHOWERS WILL DEVELOP AND
GROW IN COVERAGE EARLY THIS MORNING FROM RAWLINS TO LARAMIE. THIS
BAND WILL INTENSIFY AS THE UPPER LEVEL LOW GRADUALLY DRIFTS ACROSS
NORTHEAST COLORADO. THIS BAND OF RAINFALL AND EMBEDDED TSTORMS
WILL RESULT IN LOCALIZED MVFR CONDITIONS SOUTHEAST OF A KLAR TO
KCDR LINE BY LATE THIS MORNING AND INTO THIS AFTERNOON.


&&

.FIRE WEATHER...
ISSUED AT 255 AM MDT THU AUG 28 2014

THE UPPER LOW PRESSURE SYSTEM RESPONSIBLE FOR THE INCLEMENT WEATHER
THE PAST FEW DAYS WILL MOVE EAST FROM THE CENTRAL ROCKIES TODAY TO
THE CENTRAL GREAT PLAINS FRIDAY. A MORE SCATTERED COVERAGE OF SHOWERS
AND THUNDERSTORMS IS EXPECTED TODAY. MAINLY DRIER AND WARMER CONDITIONS
ARE FORECAST FOR FRIDAY WITH JUST A SLIGHT CHANCE OF AFTERNOON
THUNDERSTORMS OVER THE MOUNTAINS AND PORTIONS OF EAST CENTRAL WYOMING
WITH THE PASSAGE OF A WEAK UPPER LEVEL DISTURBANCE. ISOLATED TO
SCATTERED MAINLY AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS ARE
FORECAST SATURDAY AND SUNDAY AS A MORE SIGNIFICANT UPPER TROUGH AND
COLD FRONT AFFECT THE DISTRICTS. WARM TEMPERATURES SATURDAY WILL TURN
COOLER SUNDAY FOLLOWING THE COLD FRONTAL PASSAGE. THE TIGHT PRESSURE
GRADIENT WILL RESULT IN GUSTY WESTERLY WINDS THIS WEEKEND.

&&

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

$$

UPDATE...HAMMER
SHORT TERM...JAMSKI
LONG TERM...TJT
AVIATION...TJT
FIRE WEATHER...JAMSKI







000
FXUS65 KCYS 281659
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
1059 AM MDT THU AUG 28 2014

.UPDATE...
ISSUED AT 1039 AM MDT THU AUG 28 2014

A VIGOROUS MIDLVL SHORTWAVE CONTINUES TO ROTATE ACROSS THE WESTERN
NE PANHANDLE THIS MORNING. WRAP-AROUND MOISTURE ON THE BACK SIDE
OF THIS SYSTEM IS CONTRIBUTING TO WIDESPREAD SHOWERS OR STRATIFORM
RAIN ALONG A LINE FROM CENTENNIAL TO WHEATLAND. HAVE RECENTLY SEEN
SOME HIGHER ECHOS IN CENTRAL PLATTE COUNTY...AS WELL AS SOME AREAS
ALONG THE WEST EDGE OF THE LARAMIE RANGE. 1-2 INCHES OF RAIN ON
WED MORNING AND AFTN LENDS SOME CONCERN TO FLOODING POTENTIAL IF
RATES ARE HIGH ENOUGH AND/OR WE SEE MORE TRAINING. FFMP DATA ALSO
SHOWS AREAS NORTHEAST OF BOSLER HAVE ALREADY RECEIVED CLOSE TO 2
INCHES OF RAIN TODAY. WILL CONTINUE TO MONITOR CLOSELY THROUGH
THE DAY FOR POSSIBLE STATEMENTS...BUT CURRENT WEBCAMS SUGGEST THE
GROUND IS ABSORBING THINGS WELL. ONGOING CLOUDS AND RAIN WILL MAKE
IT TOUGH TO REACH FCST HIGHS...SO IN A RECENT UPDATE HAVE CUT BACK
ON TEMPS BY 5-10 DEGREES WHERE MOST OF THE PRECIP IS OCCURRING PER
THE LATEST KCYS RADAR LOOP. ALSO BUMPED UP POPS INTO THE LIKELY
CATEGORY FOR FAR SOUTHEAST WY AND WESTERN NE...EXPANDING EASTWARD
WITH TIME.

&&

.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 425 AM MDT THU AUG 28 2014

PREDAWN WATER VAPOR IMAGERY SHOWED THE UPPER LOW OVER SOUTHERN WY/NORTHERN
CO. AT THE SURFACE...A FRONT EXTENDED FROM THE MID-ATLANTIC REGION ACROSS
THE TN VALLEY TO A LOW ALONG THE CENTRAL NE/KS BORDER THEN SOUTHWEST
TO ANOTHER LOW IN SOUTHEAST CO. A LARGE CLUSTER OF STRONG CONVECTION
DEVELOPED ALONG AND JUST NORTH OF THE FRONT OVER SOUTH CENTRAL/SOUTHEAST
NE. LIGHT SHOWERS WERE DEVELOPING AND MOVING SOUTHWEST FROM EAST CENTRAL
TO SOUTH CENTRAL WY.

THE 00Z CONSENSUS MODEL GUIDANCE WEAKENS THE UPPER LOW TO AN OPEN WAVE
THIS MORNING OVER THE HIGH PLAINS...PROGRESSING SLOWLY EAST INTO THE
CENTRAL GREAT PLAINS FRIDAY. CONVECTIVE COVERAGE TODAY WILL BE LESS
THAN THE PAST FEW DAYS WITH THE RISK FOR HEAVY RAINFALL FROM THE CENTRAL
PLAINS TO THE UPPER MS VALLEY. WRAPAROUND MOISTURE OVER NORTHERN AND
WESTERN PORTIONS OF THE CWA THIS MORNING WILL GRADUALLY SLIDE EAST
THIS AFTERNOON AND EARLY EVENING. THERE WILL BE ENOUGH INSTABILITY FROM
DAYTIME HEATING FOR SCATTERED SHOWERS/TSTORMS THIS AFTERNOON...ESPECIALLY
SOUTH OF A RAWLINS WY TO ALLIANCE NE LINE. HIGH TEMPERATURES TODAY WILL
BE SLIGHTLY WARMER WITH 70S FOR LOWER ELEVATIONS.

A FEW LINGERING SHOWERS OR TSTORMS OVER THE EXTREME SOUTHERN NE PANHANDLE
EARLY THIS EVENING. OTHERWISE...SUBSIDENCE AND DRIER MORE STABLE AIRMASS
WILL SPREAD WEST TO EAST WITH THE APPROACH AND PASSAGE OF A SHORTWAVE
RIDGE.

A WEAK SHORTWAVE OVER THE NORTHERN ROCKIES EARLY FRIDAY MORNING MAKES
A BEELINE FOR THE NORTHERN HIGH PLAINS FRIDAY AFTERNOON. MOISTURE WILL
BE LIMITED WITH MARGINAL INSTABILITY FOR ISOLATED AFTERNOON TSTORMS
OVER THE MOUNTAINS AND NEARBY PLAINS OF SOUTHEAST WY. HIGH TEMPERATURES
WILL WARM INTO THE 80S EAST OF THE LARAMIE RANGE...WITH 60S AND 70S
WEST. EXPECT TRANQUIL CONDITIONS FRIDAY NIGHT WITH THE PASSAGE OF
ANOTHER SHORTWAVE RIDGE.

LATEST MODELS CONTINUE TO DEPICT A MORE SIGNIFICANT UPPER TROUGH TAKING
SHAPE OVER THE GREAT BASIN AND PACIFIC NORTHWEST SATURDAY. A RATHER
STRONG PACIFIC COLD FRONT WILL BE MOVING THROUGH NORTHERN AND WESTERN
WY DURING THE AFTERNOON. 700MB WINDS INCREASE TO 35 KT FROM THE WEST
AND SOUTHWEST. PACIFIC MOISTURE WILL ALSO INCREASE BY LATE AFTERNOON
WITH WIDELY SCATTERED SHOWERS/TSTORMS DEVELOPING ALONG AND WEST OF A
CHADRON NE TO CHEYENNE WY LINE. A TIGHTER SURFACE PRESSURE GRADIENT
WILL CREATE RATHER BREEZY WEST TO SOUTHWEST WINDS. IT WILL BE A WARM
AFTERNOON WITH HIGHS IN THE 80S TO LOWER 90S FOR THE PLAINS...WITH 60S
AND 70S WEST.

.LONG TERM...(SATURDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 350 AM MDT THU AUG 28 2014

MEDIUM AND LONG RANGE MODELS IN GOOD AGREEMENT INTO EARLY NEXT WEEK.
THE MAIN FORECAST CONCERN WILL BE A BROAD UPPER LEVEL TROUGH AND
ASSOCIATED COLD FRONT FOR LATER THIS WEEKEND. THE COLD FRONT APPEARS
TO BE RATHER STRONG FOR THIS TIME OF THE YEAR...WITH GUSTY WINDS
POSSIBLE ALONG WITH RAIN SHOWERS/TSTORMS OVER MOST OF THE AREA.
CANNOT RULE OUT SOME SNOWFALL ACROSS THE HIGH MOUNTAINS AS THIS FRONT
MOVES ACROSS THE AREA SATURDAY NIGHT AND INTO EARLY SUNDAY. MODELS
IN GOOD AGREEMENT WITH THE TIMING...ALTHOUGH THE GFS IS NOTICEABLY
MORE PROGRESSIVE AND DRIER. PREFER THE ECMWF AND GEM AT THIS TIME
SINCE BOTH THESE MODELS DID BETTER WITH THIS LAST STORM SYSTEM 3
DAYS OUT IN TERMS OF TIMING AND EVOLUTION. INCREASED POP ABOVE 30
PERCENT ACROSS MOST OF THE FORECAST AREA FOR SCATTERED SHOWERS AND
ISOLATED TSTORMS. INCREASED WINDS AS WELL...ALTHOUGH MODEL
SOUNDINGS ARE SUGGESTING SUSTAINED WESTERLY WINDS BETWEEN 20 TO 30
MPH AND GUSTS AROUND 40 MPH. DID NOT INCREASE WINDS QUITE THAT
HIGH SINCE THE ECMWF SHOWS MUCH LOWER WIND SPEEDS SUNDAY AFTERNOON.
TEMPERATURES WILL REMAIN ON THE COOL SIDE AND GENERALLY IN THE
UPPER 60S TO UPPER 70S...WARMEST ACROSS THE NEBRASKA PANHANDLE.

MODELS THEN INDICATE A DRYING TREND FOR NEXT WEEK AS THE SOUTHWESTERN
MONSOON MAY BE ENDING...WHICH IS TYPICAL IN THE LATE SUMMER. MODELS
AND ENSEMBLES ALSO SHOW WHAT APPEARS TO BE A TRANSITIONAL PERIOD IN
THE PATTERN...AS THE POLAR JET STREAM BECOMES MORE DEFINED BY DAY
6 AND 7 NEAR THE CANADIAN BORDER. THIS WILL RESULT IN QUASI-ZONAL
FLOW OVER THE WESTERN TWO THIRDS OF THE UNITED STATES. HOWEVER...THE
ECMWF AND GEM DO SHOW AN UPPER LEVEL DISTURBANCE MOVING SOUTHEAST
ACROSS THE HIGH PLAINS LATE ON MONDAY...SO KEPT LOW POP OVER EAST
CENTRAL WYOMING AND NORTHWEST NEBRASKA. OTHERWISE...TEMPERATURES
WILL GRADUALLY INCREASE TO AROUND NORMAL FOR THIS TIME OF THE YEAR
WITH HIGHS AROUND 80 ALONG AND WEST OF THE LARAMIE RANGE AND RANGING
FROM THE LOW 80S TO THE LOW 90S ACROSS THE HIGH PLAINS EAST OF THE
LARAMIE RANGE BY WEDNESDAY AFTERNOON.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH LATE TONIGHT)
ISSUED AT 350 AM MDT THU AUG 28 2014

LOW CIGS WILL PERSIST EARLY THIS MORNING ACROSS MAINLY THE WESTERN
NEBRASKA PANHANDLE TERMINALS. FOG IS UNLIKELY AT THIS TIME DUE TO
CLOUD COVER. FOG AND LOW CIGS WILL LIFT BY MID MORNING WITH VFR
PREVAILING THROUGH NOON. THE NEXT BAND OF SHOWERS WILL DEVELOP AND
GROW IN COVERAGE EARLY THIS MORNING FROM RAWLINS TO LARAMIE. THIS
BAND WILL INTENSIFY AS THE UPPER LEVEL LOW GRADUALLY DRIFTS ACROSS
NORTHEAST COLORADO. THIS BAND OF RAINFALL AND EMBEDDED TSTORMS
WILL RESULT IN LOCALIZED MVFR CONDITIONS SOUTHEAST OF A KLAR TO
KCDR LINE BY LATE THIS MORNING AND INTO THIS AFTERNOON.


&&

.FIRE WEATHER...
ISSUED AT 255 AM MDT THU AUG 28 2014

THE UPPER LOW PRESSURE SYSTEM RESPONSIBLE FOR THE INCLEMENT WEATHER
THE PAST FEW DAYS WILL MOVE EAST FROM THE CENTRAL ROCKIES TODAY TO
THE CENTRAL GREAT PLAINS FRIDAY. A MORE SCATTERED COVERAGE OF SHOWERS
AND THUNDERSTORMS IS EXPECTED TODAY. MAINLY DRIER AND WARMER CONDITIONS
ARE FORECAST FOR FRIDAY WITH JUST A SLIGHT CHANCE OF AFTERNOON
THUNDERSTORMS OVER THE MOUNTAINS AND PORTIONS OF EAST CENTRAL WYOMING
WITH THE PASSAGE OF A WEAK UPPER LEVEL DISTURBANCE. ISOLATED TO
SCATTERED MAINLY AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS ARE
FORECAST SATURDAY AND SUNDAY AS A MORE SIGNIFICANT UPPER TROUGH AND
COLD FRONT AFFECT THE DISTRICTS. WARM TEMPERATURES SATURDAY WILL TURN
COOLER SUNDAY FOLLOWING THE COLD FRONTAL PASSAGE. THE TIGHT PRESSURE
GRADIENT WILL RESULT IN GUSTY WESTERLY WINDS THIS WEEKEND.

&&

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

$$

UPDATE...HAMMER
SHORT TERM...JAMSKI
LONG TERM...TJT
AVIATION...TJT
FIRE WEATHER...JAMSKI







000
FXUS65 KCYS 281659
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
1059 AM MDT THU AUG 28 2014

.UPDATE...
ISSUED AT 1039 AM MDT THU AUG 28 2014

A VIGOROUS MIDLVL SHORTWAVE CONTINUES TO ROTATE ACROSS THE WESTERN
NE PANHANDLE THIS MORNING. WRAP-AROUND MOISTURE ON THE BACK SIDE
OF THIS SYSTEM IS CONTRIBUTING TO WIDESPREAD SHOWERS OR STRATIFORM
RAIN ALONG A LINE FROM CENTENNIAL TO WHEATLAND. HAVE RECENTLY SEEN
SOME HIGHER ECHOS IN CENTRAL PLATTE COUNTY...AS WELL AS SOME AREAS
ALONG THE WEST EDGE OF THE LARAMIE RANGE. 1-2 INCHES OF RAIN ON
WED MORNING AND AFTN LENDS SOME CONCERN TO FLOODING POTENTIAL IF
RATES ARE HIGH ENOUGH AND/OR WE SEE MORE TRAINING. FFMP DATA ALSO
SHOWS AREAS NORTHEAST OF BOSLER HAVE ALREADY RECEIVED CLOSE TO 2
INCHES OF RAIN TODAY. WILL CONTINUE TO MONITOR CLOSELY THROUGH
THE DAY FOR POSSIBLE STATEMENTS...BUT CURRENT WEBCAMS SUGGEST THE
GROUND IS ABSORBING THINGS WELL. ONGOING CLOUDS AND RAIN WILL MAKE
IT TOUGH TO REACH FCST HIGHS...SO IN A RECENT UPDATE HAVE CUT BACK
ON TEMPS BY 5-10 DEGREES WHERE MOST OF THE PRECIP IS OCCURRING PER
THE LATEST KCYS RADAR LOOP. ALSO BUMPED UP POPS INTO THE LIKELY
CATEGORY FOR FAR SOUTHEAST WY AND WESTERN NE...EXPANDING EASTWARD
WITH TIME.

&&

.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 425 AM MDT THU AUG 28 2014

PREDAWN WATER VAPOR IMAGERY SHOWED THE UPPER LOW OVER SOUTHERN WY/NORTHERN
CO. AT THE SURFACE...A FRONT EXTENDED FROM THE MID-ATLANTIC REGION ACROSS
THE TN VALLEY TO A LOW ALONG THE CENTRAL NE/KS BORDER THEN SOUTHWEST
TO ANOTHER LOW IN SOUTHEAST CO. A LARGE CLUSTER OF STRONG CONVECTION
DEVELOPED ALONG AND JUST NORTH OF THE FRONT OVER SOUTH CENTRAL/SOUTHEAST
NE. LIGHT SHOWERS WERE DEVELOPING AND MOVING SOUTHWEST FROM EAST CENTRAL
TO SOUTH CENTRAL WY.

THE 00Z CONSENSUS MODEL GUIDANCE WEAKENS THE UPPER LOW TO AN OPEN WAVE
THIS MORNING OVER THE HIGH PLAINS...PROGRESSING SLOWLY EAST INTO THE
CENTRAL GREAT PLAINS FRIDAY. CONVECTIVE COVERAGE TODAY WILL BE LESS
THAN THE PAST FEW DAYS WITH THE RISK FOR HEAVY RAINFALL FROM THE CENTRAL
PLAINS TO THE UPPER MS VALLEY. WRAPAROUND MOISTURE OVER NORTHERN AND
WESTERN PORTIONS OF THE CWA THIS MORNING WILL GRADUALLY SLIDE EAST
THIS AFTERNOON AND EARLY EVENING. THERE WILL BE ENOUGH INSTABILITY FROM
DAYTIME HEATING FOR SCATTERED SHOWERS/TSTORMS THIS AFTERNOON...ESPECIALLY
SOUTH OF A RAWLINS WY TO ALLIANCE NE LINE. HIGH TEMPERATURES TODAY WILL
BE SLIGHTLY WARMER WITH 70S FOR LOWER ELEVATIONS.

A FEW LINGERING SHOWERS OR TSTORMS OVER THE EXTREME SOUTHERN NE PANHANDLE
EARLY THIS EVENING. OTHERWISE...SUBSIDENCE AND DRIER MORE STABLE AIRMASS
WILL SPREAD WEST TO EAST WITH THE APPROACH AND PASSAGE OF A SHORTWAVE
RIDGE.

A WEAK SHORTWAVE OVER THE NORTHERN ROCKIES EARLY FRIDAY MORNING MAKES
A BEELINE FOR THE NORTHERN HIGH PLAINS FRIDAY AFTERNOON. MOISTURE WILL
BE LIMITED WITH MARGINAL INSTABILITY FOR ISOLATED AFTERNOON TSTORMS
OVER THE MOUNTAINS AND NEARBY PLAINS OF SOUTHEAST WY. HIGH TEMPERATURES
WILL WARM INTO THE 80S EAST OF THE LARAMIE RANGE...WITH 60S AND 70S
WEST. EXPECT TRANQUIL CONDITIONS FRIDAY NIGHT WITH THE PASSAGE OF
ANOTHER SHORTWAVE RIDGE.

LATEST MODELS CONTINUE TO DEPICT A MORE SIGNIFICANT UPPER TROUGH TAKING
SHAPE OVER THE GREAT BASIN AND PACIFIC NORTHWEST SATURDAY. A RATHER
STRONG PACIFIC COLD FRONT WILL BE MOVING THROUGH NORTHERN AND WESTERN
WY DURING THE AFTERNOON. 700MB WINDS INCREASE TO 35 KT FROM THE WEST
AND SOUTHWEST. PACIFIC MOISTURE WILL ALSO INCREASE BY LATE AFTERNOON
WITH WIDELY SCATTERED SHOWERS/TSTORMS DEVELOPING ALONG AND WEST OF A
CHADRON NE TO CHEYENNE WY LINE. A TIGHTER SURFACE PRESSURE GRADIENT
WILL CREATE RATHER BREEZY WEST TO SOUTHWEST WINDS. IT WILL BE A WARM
AFTERNOON WITH HIGHS IN THE 80S TO LOWER 90S FOR THE PLAINS...WITH 60S
AND 70S WEST.

.LONG TERM...(SATURDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 350 AM MDT THU AUG 28 2014

MEDIUM AND LONG RANGE MODELS IN GOOD AGREEMENT INTO EARLY NEXT WEEK.
THE MAIN FORECAST CONCERN WILL BE A BROAD UPPER LEVEL TROUGH AND
ASSOCIATED COLD FRONT FOR LATER THIS WEEKEND. THE COLD FRONT APPEARS
TO BE RATHER STRONG FOR THIS TIME OF THE YEAR...WITH GUSTY WINDS
POSSIBLE ALONG WITH RAIN SHOWERS/TSTORMS OVER MOST OF THE AREA.
CANNOT RULE OUT SOME SNOWFALL ACROSS THE HIGH MOUNTAINS AS THIS FRONT
MOVES ACROSS THE AREA SATURDAY NIGHT AND INTO EARLY SUNDAY. MODELS
IN GOOD AGREEMENT WITH THE TIMING...ALTHOUGH THE GFS IS NOTICEABLY
MORE PROGRESSIVE AND DRIER. PREFER THE ECMWF AND GEM AT THIS TIME
SINCE BOTH THESE MODELS DID BETTER WITH THIS LAST STORM SYSTEM 3
DAYS OUT IN TERMS OF TIMING AND EVOLUTION. INCREASED POP ABOVE 30
PERCENT ACROSS MOST OF THE FORECAST AREA FOR SCATTERED SHOWERS AND
ISOLATED TSTORMS. INCREASED WINDS AS WELL...ALTHOUGH MODEL
SOUNDINGS ARE SUGGESTING SUSTAINED WESTERLY WINDS BETWEEN 20 TO 30
MPH AND GUSTS AROUND 40 MPH. DID NOT INCREASE WINDS QUITE THAT
HIGH SINCE THE ECMWF SHOWS MUCH LOWER WIND SPEEDS SUNDAY AFTERNOON.
TEMPERATURES WILL REMAIN ON THE COOL SIDE AND GENERALLY IN THE
UPPER 60S TO UPPER 70S...WARMEST ACROSS THE NEBRASKA PANHANDLE.

MODELS THEN INDICATE A DRYING TREND FOR NEXT WEEK AS THE SOUTHWESTERN
MONSOON MAY BE ENDING...WHICH IS TYPICAL IN THE LATE SUMMER. MODELS
AND ENSEMBLES ALSO SHOW WHAT APPEARS TO BE A TRANSITIONAL PERIOD IN
THE PATTERN...AS THE POLAR JET STREAM BECOMES MORE DEFINED BY DAY
6 AND 7 NEAR THE CANADIAN BORDER. THIS WILL RESULT IN QUASI-ZONAL
FLOW OVER THE WESTERN TWO THIRDS OF THE UNITED STATES. HOWEVER...THE
ECMWF AND GEM DO SHOW AN UPPER LEVEL DISTURBANCE MOVING SOUTHEAST
ACROSS THE HIGH PLAINS LATE ON MONDAY...SO KEPT LOW POP OVER EAST
CENTRAL WYOMING AND NORTHWEST NEBRASKA. OTHERWISE...TEMPERATURES
WILL GRADUALLY INCREASE TO AROUND NORMAL FOR THIS TIME OF THE YEAR
WITH HIGHS AROUND 80 ALONG AND WEST OF THE LARAMIE RANGE AND RANGING
FROM THE LOW 80S TO THE LOW 90S ACROSS THE HIGH PLAINS EAST OF THE
LARAMIE RANGE BY WEDNESDAY AFTERNOON.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH LATE TONIGHT)
ISSUED AT 350 AM MDT THU AUG 28 2014

LOW CIGS WILL PERSIST EARLY THIS MORNING ACROSS MAINLY THE WESTERN
NEBRASKA PANHANDLE TERMINALS. FOG IS UNLIKELY AT THIS TIME DUE TO
CLOUD COVER. FOG AND LOW CIGS WILL LIFT BY MID MORNING WITH VFR
PREVAILING THROUGH NOON. THE NEXT BAND OF SHOWERS WILL DEVELOP AND
GROW IN COVERAGE EARLY THIS MORNING FROM RAWLINS TO LARAMIE. THIS
BAND WILL INTENSIFY AS THE UPPER LEVEL LOW GRADUALLY DRIFTS ACROSS
NORTHEAST COLORADO. THIS BAND OF RAINFALL AND EMBEDDED TSTORMS
WILL RESULT IN LOCALIZED MVFR CONDITIONS SOUTHEAST OF A KLAR TO
KCDR LINE BY LATE THIS MORNING AND INTO THIS AFTERNOON.


&&

.FIRE WEATHER...
ISSUED AT 255 AM MDT THU AUG 28 2014

THE UPPER LOW PRESSURE SYSTEM RESPONSIBLE FOR THE INCLEMENT WEATHER
THE PAST FEW DAYS WILL MOVE EAST FROM THE CENTRAL ROCKIES TODAY TO
THE CENTRAL GREAT PLAINS FRIDAY. A MORE SCATTERED COVERAGE OF SHOWERS
AND THUNDERSTORMS IS EXPECTED TODAY. MAINLY DRIER AND WARMER CONDITIONS
ARE FORECAST FOR FRIDAY WITH JUST A SLIGHT CHANCE OF AFTERNOON
THUNDERSTORMS OVER THE MOUNTAINS AND PORTIONS OF EAST CENTRAL WYOMING
WITH THE PASSAGE OF A WEAK UPPER LEVEL DISTURBANCE. ISOLATED TO
SCATTERED MAINLY AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS ARE
FORECAST SATURDAY AND SUNDAY AS A MORE SIGNIFICANT UPPER TROUGH AND
COLD FRONT AFFECT THE DISTRICTS. WARM TEMPERATURES SATURDAY WILL TURN
COOLER SUNDAY FOLLOWING THE COLD FRONTAL PASSAGE. THE TIGHT PRESSURE
GRADIENT WILL RESULT IN GUSTY WESTERLY WINDS THIS WEEKEND.

&&

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

$$

UPDATE...HAMMER
SHORT TERM...JAMSKI
LONG TERM...TJT
AVIATION...TJT
FIRE WEATHER...JAMSKI







000
FXUS63 KUNR 281551
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
951 AM MDT THU AUG 28 2014

.UPDATE...
ISSUED AT 950 AM MDT THU AUG 28 2014

CURRENT SURFACE ANALYSIS SHOWS LOW PRESSURE OVER CENTRAL NEB...
WITH INVERTED TROF STRETCHING NORTHWARD ACROSS CENTRAL SD. HIGH
PRESSURE IS IN PLACE OVER THE CENTRAL ROCKIES. UPPER LEVEL
ANALYSIS SHOWS LOW NOW OVER WESTERN NEB...SLOWLY MOVING EAST-
SOUTHEAST. KUDX RADAR SHOWS ISOLATED TO SCATTERED SHOWERS FROM
CENTRAL SD TO FAR SOUTHWEST SD. THERE ARE A FEW LIGHTNING STRIKES
FROM TIME TO TIME WITH THE ACTIVITY OVER SOUTH CENTRAL SD. SKIES
RANGE FROM MOSTLY SUNNY OVER NORTHEAST WY TO MAINLY CLOUDY EAST OF
THE BLACK HILLS. TEMPS ARE IN THE 60S AND LOWER 70S WITH LIGHT AND
VARIABLE WINDS.

SHOWER AND THUNDERSTORM ACTIVITY WILL LINGER OVER MUCH OF
SOUTHWESTERN INTO CENTRAL SD INTO THE AFTERNOON...WITH A GRADUAL
EASTWARD SHIFT THROUGH THE AFTERNOON. MAY NEED TO ADD SOME POPS
FOR THE EARLY EVENING ACROSS SOUTH CENTRAL SD IF THE EASTWARD
TREND SLOWS DOWN A BIT. CLOUDS WILL ALSO GRADUALLY DECREASE FROM
WEST TO EAST ACROSS THE AREA THROUGH THE EVENING. HIGH TEMPS MIGHT
BE A BIT TOO HIGH IN SOME AREAS...BUT WILL SEE HOW QUICKLY THEY
RISE OVER THE NEXT 2 OR 3 HOURS BEFORE MAKING ANYMORE ADJUSTMENTS.
UPDATED FORECAST HAS BEEN SENT TO MAKE SHORT TERM CHANGES TO
POPS...CLOUD COVER...AND WIND.

&&

.SHORT TERM...TODAY THROUGH FRIDAY NIGHT
ISSUED AT 302 AM MDT THU AUG 28 2014

CURRENT SURFACE ANALYSIS SHOWS LOW PRESSURE OVER SASKATCHEWAN...WITH
A FRONTAL BOUNDARY EXTENDING THROUGH EASTERN MONTANA AND CENTRAL
WYOMING. UPPER LEVEL ANALYSIS SHOWS MAIN LOW PRESSURE AREA OVER NRN
COLORADO/SRN WYOMING WITH A TROF COVERING THE ROCKIES AND HIGH
PLAINS. LATEST RADAR IMAGERY SHOWS SHOWERS CONTINUING TO ROTATE AND
LIFT NORTH ACROSS THE SD PLAINS. A LITTLE EMBEDDED CONVECTION IS ALSO
OCCURRING IN SOUTH CENTRAL SD.

AS THE UPPER LOW MOVES SLOWLY EAST INTO THE CENTRAL HIGH PLAINS...
SHOWER/THUNDERSTORM ACTIVITY WILL QUICKLY DECREASE FROM WEST TO
EAST...WITH SHOWERS/STORMS CONTINUING ACROSS MUCH OF SOUTH CENTRAL
SOUTH DAKOTA. WITH A LOT OF LOW LEVEL MOISTURE AROUND...EXPECT
AREAS OF FOG TO LINGER INTO THE MORNING HOURS ACROSS MOST OF THE
WRN SD PLAINS. BY THIS AFTERNOON...DIURNAL HEATING AND LINGERING
INSTABILITY COULD PRODUCE A TERRAIN INDUCED SHOWER/STORM OVER THE
BLACK HILLS. THUS LEFT ISOLD POPS IN THE FORECAST. TEMPS TODAY
WILL BE WARMER WITH DECREASING CLOUDS...ESPECIALLY ACROSS THE NRN
AND WRN AREAS.

FOR TONIGHT...CLOUDS WILL CONTINUE TO GRADUALLY DECREASE FROM
NORTHWEST TO SOUTHEAST...WITH MOSTLY CLEAR SKIES OVERNIGHT. THIS
COMBINED WITH LIGHT WINDS AND SURFACE HIGH PRESSURE TO THE
WEST...DECIDED TO ADD SOME FOG FOR THE SD PLAINS. TEMPS WILL BE
NEAR NORMAL.

ON FRIDAY...SHORTWAVE TROF MOVES RAPIDLY ACROSS MT/ND PUSHING A WEAK
COOL FRONT INTO WESTERN SD. FORECAST SOUNDINGS SUPPORT 250-500J/KG
MLCAPE...WITH SUFFICIENT LOW LEVEL MOISTURE/CAPE/SHEAR FOR STORMS.
MOST OF THE 500-700MB MOISTURE REMAINS NORTH OF THE CWA...HOWEVER
COULD SEE SCATTERED STORMS WITH AN ISOLATED STRONG STORM ACROSS
NORTHWEST HALF OF CWA. TEMPERATURES ON FRIDAY WILL BE A LITTLE
COOLER THAN TODAY IN THE NW...BUT MOST AREAS WILL SEE WARMER
TEMPERATURES.

&&

.LONG TERM...SATURDAY THROUGH WEDNESDAY
ISSUED AT 302 AM MDT THU AUG 28 2014

PROGRESSIVE NORTHERN STREAM FLOW WILL CONTINUE THROUGH THE PERIOD
WITH A LONG WAVE UPPER LEVEL TROUGH ON TRACK TO ADVECT THROUGH THE
REGION SAT-SUN...WITH A WEAKER SHORTWAVE IMPULSE POSSIBLE MONDAY.
TROUGH RELOADING OVER THE NE PAC TUE-WED FAVORED IN ECMWF/GFS
SOLUTIONS...WHICH WOULD SUPPORT MEAN RIDGING OVER THE NORTHERN
PLAINS WITH DRY AND WARMER CONDITIONS. MAIN FORECAST TREND IS A
QUICKER ARRIVAL OF THE EXPECTED LONG WAVE TROUGH SAT...WITH PRECIP
CHANCES INCREASING SAT AFTERNOON WESTERN THIRD. OTHERWISE...THE
REMAINDER OF THE FORECAST IS ON TRACK ATTM.

UPPER LEVEL TROUGH WILL PUSH OUT OF THE NE PAC AND INTO THE NORTHERN
PLAINS...SUPPORTING INCREASING LSA SAT THROUGH SUNDAY. LEE SIDE SFC
TROUGH WILL WILL INTERACT WITH THE APPROACHING UPPER WAVE SUPPORTING
A FOCUS FOR SHRA/TS ACTIVITY OVER THE WESTERN FA BY SAT AFTERNOON.
LL SE FLOW AHEAD OF THIS SYSTEM WITH MOIST UPPER LEVEL SW FLOW WILL
SUPPORT INCREASING PW OVER THE REGION...WITH PLENTY OF MOISTURE
BEING AVAILABLE WITH THIS SYSTEM. SOME MODEL INDICATION FOR
SUFFICIENT DEEP LAYER SHEAR AND CAPE OVER THE FAR NW ZONES...ESP NW
SD BY SAT EVENING...SUPPORTING A POSSIBLE SEVERE THREAT THERE.
SOMETHING TO WATCH. HAVE ADJUSTED POPS UP SAT AFTERNOON AND SAT
EVENING...WITH THE PRIMARY SOUTHERN PERIPHERY IMPULSE EXPECTED TO
SHIFT NE ACROSS THE NW FA. TRAILING SFC TROUGH WITH SUFFICIENT LSA
SHOULD SUPPORT A GOOD CHANCE OF SHRA/TS NW THIRD...WITH MORE
SCT/ISOLD ACTIVITY ACROSS THE REMAINDER OF THE FA. UPPER LEVEL COLD
POOL WILL SUPPORT STEEP LL LAPSE RATES OVER THE FA SUNDAY WITH
RESIDUAL LL MOISTURE IN PLACE. DIURNAL HEATING COUPLED WITH BH/NE WY
TERRAIN INFLUENCES SHOULD SUPPORT SCT TO ISOLD SHRA/TS SW HALF OF
THE FA. BUMPED POPS UP OVER THE BH. OTHERWISE...ONE MORE WEAKER
WESTERLY FLOW IMPULSE STILL INDICATED IN FORECAST MODELS
MONDAY...POSSIBLY SUPPORTING A FEW SHRA/TS...ALTHOUGH UPPER LEVEL
SUPPORT LOOKS MARGINAL ATTM...ESP WITH DRY PROFILES. DRY CONDS
EXPECTED TUE-WED WITH MEAN DEEP LAYER RIDGING.

SEASONAL TEMPS EXPECTED IN MOST OF THE PERIOD...WITH BELOW NORMAL
TEMPS /5-10 DEGREES/ EXPECTED SUNDAY THROUGH MONDAY...ESP NW AREAS.
THE WARMEST DAY IN PERIOD LOOKS TO BE SAT...ESP ON THE SD PLAINS.
ALTHOUGH THERE IS SOME INDICATION FOR WARM CONDITIONS NEXT WED GIVEN
SW WAA FLOW AHEAD OF THE NEXT POTENTIAL EJECTING NE PAC UPPER
TROUGH.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 517 AM MDT THU AUG 28 2014

UPPER LEVEL IMPULSE AND ASSOCIATED RAINS WILL WANE AND SHIFT EAST
THROUGH AFTERNOON...AFFECTING MAINLY THE FAR EASTERN FA...ESP
SCENTRAL SD. MVFR/IFR/LOCAL LIFR CONDS CAN BE EXPECTED THERE. ANY
IFR/LIFR CONDS WILL LIKELY TREND TO MVFR THROUGH AFTERNOON. VFR
CONDS EXPECTED ELSEWHERE. MVFR/IFR CONDS EXPECTED TO REDEVELOP ON
THE SD PLAINS OVERNIGHT /ESP CENTRAL SD/...WITH LCL LIFR/VLIFR CONDS
POSSIBLE IN FOG. NOT EXPECTING RESTRICTIONS AT KRAP OR KGCC
TONIGHT. CONDITIONS WILL SLOWLY IMPROVE LATE FRIDAY MORNING.


&&

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

$$

UPDATE...26
SHORT TERM...MLS
LONG TERM...JC
AVIATION...JC







000
FXUS63 KUNR 281551
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
951 AM MDT THU AUG 28 2014

.UPDATE...
ISSUED AT 950 AM MDT THU AUG 28 2014

CURRENT SURFACE ANALYSIS SHOWS LOW PRESSURE OVER CENTRAL NEB...
WITH INVERTED TROF STRETCHING NORTHWARD ACROSS CENTRAL SD. HIGH
PRESSURE IS IN PLACE OVER THE CENTRAL ROCKIES. UPPER LEVEL
ANALYSIS SHOWS LOW NOW OVER WESTERN NEB...SLOWLY MOVING EAST-
SOUTHEAST. KUDX RADAR SHOWS ISOLATED TO SCATTERED SHOWERS FROM
CENTRAL SD TO FAR SOUTHWEST SD. THERE ARE A FEW LIGHTNING STRIKES
FROM TIME TO TIME WITH THE ACTIVITY OVER SOUTH CENTRAL SD. SKIES
RANGE FROM MOSTLY SUNNY OVER NORTHEAST WY TO MAINLY CLOUDY EAST OF
THE BLACK HILLS. TEMPS ARE IN THE 60S AND LOWER 70S WITH LIGHT AND
VARIABLE WINDS.

SHOWER AND THUNDERSTORM ACTIVITY WILL LINGER OVER MUCH OF
SOUTHWESTERN INTO CENTRAL SD INTO THE AFTERNOON...WITH A GRADUAL
EASTWARD SHIFT THROUGH THE AFTERNOON. MAY NEED TO ADD SOME POPS
FOR THE EARLY EVENING ACROSS SOUTH CENTRAL SD IF THE EASTWARD
TREND SLOWS DOWN A BIT. CLOUDS WILL ALSO GRADUALLY DECREASE FROM
WEST TO EAST ACROSS THE AREA THROUGH THE EVENING. HIGH TEMPS MIGHT
BE A BIT TOO HIGH IN SOME AREAS...BUT WILL SEE HOW QUICKLY THEY
RISE OVER THE NEXT 2 OR 3 HOURS BEFORE MAKING ANYMORE ADJUSTMENTS.
UPDATED FORECAST HAS BEEN SENT TO MAKE SHORT TERM CHANGES TO
POPS...CLOUD COVER...AND WIND.

&&

.SHORT TERM...TODAY THROUGH FRIDAY NIGHT
ISSUED AT 302 AM MDT THU AUG 28 2014

CURRENT SURFACE ANALYSIS SHOWS LOW PRESSURE OVER SASKATCHEWAN...WITH
A FRONTAL BOUNDARY EXTENDING THROUGH EASTERN MONTANA AND CENTRAL
WYOMING. UPPER LEVEL ANALYSIS SHOWS MAIN LOW PRESSURE AREA OVER NRN
COLORADO/SRN WYOMING WITH A TROF COVERING THE ROCKIES AND HIGH
PLAINS. LATEST RADAR IMAGERY SHOWS SHOWERS CONTINUING TO ROTATE AND
LIFT NORTH ACROSS THE SD PLAINS. A LITTLE EMBEDDED CONVECTION IS ALSO
OCCURRING IN SOUTH CENTRAL SD.

AS THE UPPER LOW MOVES SLOWLY EAST INTO THE CENTRAL HIGH PLAINS...
SHOWER/THUNDERSTORM ACTIVITY WILL QUICKLY DECREASE FROM WEST TO
EAST...WITH SHOWERS/STORMS CONTINUING ACROSS MUCH OF SOUTH CENTRAL
SOUTH DAKOTA. WITH A LOT OF LOW LEVEL MOISTURE AROUND...EXPECT
AREAS OF FOG TO LINGER INTO THE MORNING HOURS ACROSS MOST OF THE
WRN SD PLAINS. BY THIS AFTERNOON...DIURNAL HEATING AND LINGERING
INSTABILITY COULD PRODUCE A TERRAIN INDUCED SHOWER/STORM OVER THE
BLACK HILLS. THUS LEFT ISOLD POPS IN THE FORECAST. TEMPS TODAY
WILL BE WARMER WITH DECREASING CLOUDS...ESPECIALLY ACROSS THE NRN
AND WRN AREAS.

FOR TONIGHT...CLOUDS WILL CONTINUE TO GRADUALLY DECREASE FROM
NORTHWEST TO SOUTHEAST...WITH MOSTLY CLEAR SKIES OVERNIGHT. THIS
COMBINED WITH LIGHT WINDS AND SURFACE HIGH PRESSURE TO THE
WEST...DECIDED TO ADD SOME FOG FOR THE SD PLAINS. TEMPS WILL BE
NEAR NORMAL.

ON FRIDAY...SHORTWAVE TROF MOVES RAPIDLY ACROSS MT/ND PUSHING A WEAK
COOL FRONT INTO WESTERN SD. FORECAST SOUNDINGS SUPPORT 250-500J/KG
MLCAPE...WITH SUFFICIENT LOW LEVEL MOISTURE/CAPE/SHEAR FOR STORMS.
MOST OF THE 500-700MB MOISTURE REMAINS NORTH OF THE CWA...HOWEVER
COULD SEE SCATTERED STORMS WITH AN ISOLATED STRONG STORM ACROSS
NORTHWEST HALF OF CWA. TEMPERATURES ON FRIDAY WILL BE A LITTLE
COOLER THAN TODAY IN THE NW...BUT MOST AREAS WILL SEE WARMER
TEMPERATURES.

&&

.LONG TERM...SATURDAY THROUGH WEDNESDAY
ISSUED AT 302 AM MDT THU AUG 28 2014

PROGRESSIVE NORTHERN STREAM FLOW WILL CONTINUE THROUGH THE PERIOD
WITH A LONG WAVE UPPER LEVEL TROUGH ON TRACK TO ADVECT THROUGH THE
REGION SAT-SUN...WITH A WEAKER SHORTWAVE IMPULSE POSSIBLE MONDAY.
TROUGH RELOADING OVER THE NE PAC TUE-WED FAVORED IN ECMWF/GFS
SOLUTIONS...WHICH WOULD SUPPORT MEAN RIDGING OVER THE NORTHERN
PLAINS WITH DRY AND WARMER CONDITIONS. MAIN FORECAST TREND IS A
QUICKER ARRIVAL OF THE EXPECTED LONG WAVE TROUGH SAT...WITH PRECIP
CHANCES INCREASING SAT AFTERNOON WESTERN THIRD. OTHERWISE...THE
REMAINDER OF THE FORECAST IS ON TRACK ATTM.

UPPER LEVEL TROUGH WILL PUSH OUT OF THE NE PAC AND INTO THE NORTHERN
PLAINS...SUPPORTING INCREASING LSA SAT THROUGH SUNDAY. LEE SIDE SFC
TROUGH WILL WILL INTERACT WITH THE APPROACHING UPPER WAVE SUPPORTING
A FOCUS FOR SHRA/TS ACTIVITY OVER THE WESTERN FA BY SAT AFTERNOON.
LL SE FLOW AHEAD OF THIS SYSTEM WITH MOIST UPPER LEVEL SW FLOW WILL
SUPPORT INCREASING PW OVER THE REGION...WITH PLENTY OF MOISTURE
BEING AVAILABLE WITH THIS SYSTEM. SOME MODEL INDICATION FOR
SUFFICIENT DEEP LAYER SHEAR AND CAPE OVER THE FAR NW ZONES...ESP NW
SD BY SAT EVENING...SUPPORTING A POSSIBLE SEVERE THREAT THERE.
SOMETHING TO WATCH. HAVE ADJUSTED POPS UP SAT AFTERNOON AND SAT
EVENING...WITH THE PRIMARY SOUTHERN PERIPHERY IMPULSE EXPECTED TO
SHIFT NE ACROSS THE NW FA. TRAILING SFC TROUGH WITH SUFFICIENT LSA
SHOULD SUPPORT A GOOD CHANCE OF SHRA/TS NW THIRD...WITH MORE
SCT/ISOLD ACTIVITY ACROSS THE REMAINDER OF THE FA. UPPER LEVEL COLD
POOL WILL SUPPORT STEEP LL LAPSE RATES OVER THE FA SUNDAY WITH
RESIDUAL LL MOISTURE IN PLACE. DIURNAL HEATING COUPLED WITH BH/NE WY
TERRAIN INFLUENCES SHOULD SUPPORT SCT TO ISOLD SHRA/TS SW HALF OF
THE FA. BUMPED POPS UP OVER THE BH. OTHERWISE...ONE MORE WEAKER
WESTERLY FLOW IMPULSE STILL INDICATED IN FORECAST MODELS
MONDAY...POSSIBLY SUPPORTING A FEW SHRA/TS...ALTHOUGH UPPER LEVEL
SUPPORT LOOKS MARGINAL ATTM...ESP WITH DRY PROFILES. DRY CONDS
EXPECTED TUE-WED WITH MEAN DEEP LAYER RIDGING.

SEASONAL TEMPS EXPECTED IN MOST OF THE PERIOD...WITH BELOW NORMAL
TEMPS /5-10 DEGREES/ EXPECTED SUNDAY THROUGH MONDAY...ESP NW AREAS.
THE WARMEST DAY IN PERIOD LOOKS TO BE SAT...ESP ON THE SD PLAINS.
ALTHOUGH THERE IS SOME INDICATION FOR WARM CONDITIONS NEXT WED GIVEN
SW WAA FLOW AHEAD OF THE NEXT POTENTIAL EJECTING NE PAC UPPER
TROUGH.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 517 AM MDT THU AUG 28 2014

UPPER LEVEL IMPULSE AND ASSOCIATED RAINS WILL WANE AND SHIFT EAST
THROUGH AFTERNOON...AFFECTING MAINLY THE FAR EASTERN FA...ESP
SCENTRAL SD. MVFR/IFR/LOCAL LIFR CONDS CAN BE EXPECTED THERE. ANY
IFR/LIFR CONDS WILL LIKELY TREND TO MVFR THROUGH AFTERNOON. VFR
CONDS EXPECTED ELSEWHERE. MVFR/IFR CONDS EXPECTED TO REDEVELOP ON
THE SD PLAINS OVERNIGHT /ESP CENTRAL SD/...WITH LCL LIFR/VLIFR CONDS
POSSIBLE IN FOG. NOT EXPECTING RESTRICTIONS AT KRAP OR KGCC
TONIGHT. CONDITIONS WILL SLOWLY IMPROVE LATE FRIDAY MORNING.


&&

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

$$

UPDATE...26
SHORT TERM...MLS
LONG TERM...JC
AVIATION...JC






000
FXUS63 KUNR 281131
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
531 AM MDT THU AUG 28 2014

.SHORT TERM...TODAY THROUGH FRIDAY NIGHT
ISSUED AT 302 AM MDT THU AUG 28 2014

CURRENT SURFACE ANALYSIS SHOWS LOW PRESSURE OVER SASKATCHEWAN...WITH
A FRONTAL BOUNDARY EXTENDING THROUGH EASTERN MONTANA AND CENTRAL
WYOMING. UPPER LEVEL ANALYSIS SHOWS MAIN LOW PRESSURE AREA OVER NRN
COLORADO/SRN WYOMING WITH A TROF COVERING THE ROCKIES AND HIGH
PLAINS. LATEST RADAR IMAGERY SHOWS SHOWERS CONTINUING TO ROTATE AND
LIFT NORTH ACROSS THE SD PLAINS. A LITTLE EMBEDDED CONVECTION IS ALSO
OCCURRING IN SOUTH CENTRAL SD.

AS THE UPPER LOW MOVES SLOWLY EAST INTO THE CENTRAL HIGH PLAINS...
SHOWER/THUNDERSTORM ACTIVITY WILL QUICKLY DECREASE FROM WEST TO
EAST...WITH SHOWERS/STORMS CONTINUING ACROSS MUCH OF SOUTH CENTRAL
SOUTH DAKOTA. WITH A LOT OF LOW LEVEL MOISTURE AROUND...EXPECT
AREAS OF FOG TO LINGER INTO THE MORNING HOURS ACROSS MOST OF THE
WRN SD PLAINS. BY THIS AFTERNOON...DIURNAL HEATING AND LINGERING
INSTABILITY COULD PRODUCE A TERRAIN INDUCED SHOWER/STORM OVER THE
BLACK HILLS. THUS LEFT ISOLD POPS IN THE FORECAST. TEMPS TODAY
WILL BE WARMER WITH DECREASING CLOUDS...ESPECIALLY ACROSS THE NRN
AND WRN AREAS.

FOR TONIGHT...CLOUDS WILL CONTINUE TO GRADUALLY DECREASE FROM
NORTHWEST TO SOUTHEAST...WITH MOSTLY CLEAR SKIES OVERNIGHT. THIS
COMBINED WITH LIGHT WINDS AND SURFACE HIGH PRESSURE TO THE
WEST...DECIDED TO ADD SOME FOG FOR THE SD PLAINS. TEMPS WILL BE
NEAR NORMAL.

ON FRIDAY...SHORTWAVE TROF MOVES RAPIDLY ACROSS MT/ND PUSHING A WEAK
COOL FRONT INTO WESTERN SD. FORECAST SOUNDINGS SUPPORT 250-500J/KG
MLCAPE...WITH SUFFICIENT LOW LEVEL MOISTURE/CAPE/SHEAR FOR STORMS.
MOST OF THE 500-700MB MOISTURE REMAINS NORTH OF THE CWA...HOWEVER
COULD SEE SCATTERED STORMS WITH AN ISOLATED STRONG STORM ACROSS
NORTHWEST HALF OF CWA. TEMPERATURES ON FRIDAY WILL BE A LITTLE
COOLER THAN TODAY IN THE NW...BUT MOST AREAS WILL SEE WARMER
TEMPERATURES.

&&

.LONG TERM...SATURDAY THROUGH WEDNESDAY
ISSUED AT 302 AM MDT THU AUG 28 2014

PROGRESSIVE NORTHERN STREAM FLOW WILL CONTINUE THROUGH THE PERIOD
WITH A LONG WAVE UPPER LEVEL TROUGH ON TRACK TO ADVECT THROUGH THE
REGION SAT-SUN...WITH A WEAKER SHORTWAVE IMPULSE POSSIBLE MONDAY.
TROUGH RELOADING OVER THE NE PAC TUE-WED FAVORED IN ECMWF/GFS
SOLUTIONS...WHICH WOULD SUPPORT MEAN RIDGING OVER THE NORTHERN
PLAINS WITH DRY AND WARMER CONDITIONS. MAIN FORECAST TREND IS A
QUICKER ARRIVAL OF THE EXPECTED LONG WAVE TROUGH SAT...WITH PRECIP
CHANCES INCREASING SAT AFTERNOON WESTERN THIRD. OTHERWISE...THE
REMAINDER OF THE FORECAST IS ON TRACK ATTM.

UPPER LEVEL TROUGH WILL PUSH OUT OF THE NE PAC AND INTO THE NORTHERN
PLAINS...SUPPORTING INCREASING LSA SAT THROUGH SUNDAY. LEE SIDE SFC
TROUGH WILL WILL INTERACT WITH THE APPROACHING UPPER WAVE SUPPORTING
A FOCUS FOR SHRA/TS ACTIVITY OVER THE WESTERN FA BY SAT AFTERNOON.
LL SE FLOW AHEAD OF THIS SYSTEM WITH MOIST UPPER LEVEL SW FLOW WILL
SUPPORT INCREASING PW OVER THE REGION...WITH PLENTY OF MOISTURE
BEING AVAILABLE WITH THIS SYSTEM. SOME MODEL INDICATION FOR
SUFFICIENT DEEP LAYER SHEAR AND CAPE OVER THE FAR NW ZONES...ESP NW
SD BY SAT EVENING...SUPPORTING A POSSIBLE SEVERE THREAT THERE.
SOMETHING TO WATCH. HAVE ADJUSTED POPS UP SAT AFTERNOON AND SAT
EVENING...WITH THE PRIMARY SOUTHERN PERIPHERY IMPULSE EXPECTED TO
SHIFT NE ACROSS THE NW FA. TRAILING SFC TROUGH WITH SUFFICIENT LSA
SHOULD SUPPORT A GOOD CHANCE OF SHRA/TS NW THIRD...WITH MORE
SCT/ISOLD ACTIVITY ACROSS THE REMAINDER OF THE FA. UPPER LEVEL COLD
POOL WILL SUPPORT STEEP LL LAPSE RATES OVER THE FA SUNDAY WITH
RESIDUAL LL MOISTURE IN PLACE. DIURNAL HEATING COUPLED WITH BH/NE WY
TERRAIN INFLUENCES SHOULD SUPPORT SCT TO ISOLD SHRA/TS SW HALF OF
THE FA. BUMPED POPS UP OVER THE BH. OTHERWISE...ONE MORE WEAKER
WESTERLY FLOW IMPULSE STILL INDICATED IN FORECAST MODELS
MONDAY...POSSIBLY SUPPORTING A FEW SHRA/TS...ALTHOUGH UPPER LEVEL
SUPPORT LOOKS MARGINAL ATTM...ESP WITH DRY PROFILES. DRY CONDS
EXPECTED TUE-WED WITH MEAN DEEP LAYER RIDGING.

SEASONAL TEMPS EXPECTED IN MOST OF THE PERIOD...WITH BELOW NORMAL
TEMPS /5-10 DEGREES/ EXPECTED SUNDAY THROUGH MONDAY...ESP NW AREAS.
THE WARMEST DAY IN PERIOD LOOKS TO BE SAT...ESP ON THE SD PLAINS.
ALTHOUGH THERE IS SOME INDICATION FOR WARM CONDITIONS NEXT WED GIVEN
SW WAA FLOW AHEAD OF THE NEXT POTENTIAL EJECTING NE PAC UPPER
TROUGH.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 517 AM MDT THU AUG 28 2014

UPPER LEVEL IMPULSE AND ASSOCIATED RAINS WILL WANE AND SHIFT EAST
THROUGH AFTERNOON...AFFECTING MAINLY THE FAR EASTERN FA...ESP
SCENTRAL SD. MVFR/IFR/LOCAL LIFR CONDS CAN BE EXPECTED THERE. ANY
IFR/LIFR CONDS WILL LIKELY TREND TO MVFR THROUGH AFTERNOON. VFR
CONDS EXPECTED ELSEWHERE. MVFR/IFR CONDS EXPECTED TO REDEVELOP ON
THE SD PLAINS OVERNIGHT /ESP CENTRAL SD/...WITH LCL LIFR/VLIFR CONDS
POSSIBLE IN FOG. NOT EXPECTING RESTRICTIONS AT KRAP OR KGCC
TONIGHT. CONDITIONS WILL SLOWLY IMPROVE LATE FRIDAY MORNING.

&&

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

$$

SHORT TERM...MLS
LONG TERM...JC
AVIATION...JC







000
FXUS63 KUNR 281131
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
531 AM MDT THU AUG 28 2014

.SHORT TERM...TODAY THROUGH FRIDAY NIGHT
ISSUED AT 302 AM MDT THU AUG 28 2014

CURRENT SURFACE ANALYSIS SHOWS LOW PRESSURE OVER SASKATCHEWAN...WITH
A FRONTAL BOUNDARY EXTENDING THROUGH EASTERN MONTANA AND CENTRAL
WYOMING. UPPER LEVEL ANALYSIS SHOWS MAIN LOW PRESSURE AREA OVER NRN
COLORADO/SRN WYOMING WITH A TROF COVERING THE ROCKIES AND HIGH
PLAINS. LATEST RADAR IMAGERY SHOWS SHOWERS CONTINUING TO ROTATE AND
LIFT NORTH ACROSS THE SD PLAINS. A LITTLE EMBEDDED CONVECTION IS ALSO
OCCURRING IN SOUTH CENTRAL SD.

AS THE UPPER LOW MOVES SLOWLY EAST INTO THE CENTRAL HIGH PLAINS...
SHOWER/THUNDERSTORM ACTIVITY WILL QUICKLY DECREASE FROM WEST TO
EAST...WITH SHOWERS/STORMS CONTINUING ACROSS MUCH OF SOUTH CENTRAL
SOUTH DAKOTA. WITH A LOT OF LOW LEVEL MOISTURE AROUND...EXPECT
AREAS OF FOG TO LINGER INTO THE MORNING HOURS ACROSS MOST OF THE
WRN SD PLAINS. BY THIS AFTERNOON...DIURNAL HEATING AND LINGERING
INSTABILITY COULD PRODUCE A TERRAIN INDUCED SHOWER/STORM OVER THE
BLACK HILLS. THUS LEFT ISOLD POPS IN THE FORECAST. TEMPS TODAY
WILL BE WARMER WITH DECREASING CLOUDS...ESPECIALLY ACROSS THE NRN
AND WRN AREAS.

FOR TONIGHT...CLOUDS WILL CONTINUE TO GRADUALLY DECREASE FROM
NORTHWEST TO SOUTHEAST...WITH MOSTLY CLEAR SKIES OVERNIGHT. THIS
COMBINED WITH LIGHT WINDS AND SURFACE HIGH PRESSURE TO THE
WEST...DECIDED TO ADD SOME FOG FOR THE SD PLAINS. TEMPS WILL BE
NEAR NORMAL.

ON FRIDAY...SHORTWAVE TROF MOVES RAPIDLY ACROSS MT/ND PUSHING A WEAK
COOL FRONT INTO WESTERN SD. FORECAST SOUNDINGS SUPPORT 250-500J/KG
MLCAPE...WITH SUFFICIENT LOW LEVEL MOISTURE/CAPE/SHEAR FOR STORMS.
MOST OF THE 500-700MB MOISTURE REMAINS NORTH OF THE CWA...HOWEVER
COULD SEE SCATTERED STORMS WITH AN ISOLATED STRONG STORM ACROSS
NORTHWEST HALF OF CWA. TEMPERATURES ON FRIDAY WILL BE A LITTLE
COOLER THAN TODAY IN THE NW...BUT MOST AREAS WILL SEE WARMER
TEMPERATURES.

&&

.LONG TERM...SATURDAY THROUGH WEDNESDAY
ISSUED AT 302 AM MDT THU AUG 28 2014

PROGRESSIVE NORTHERN STREAM FLOW WILL CONTINUE THROUGH THE PERIOD
WITH A LONG WAVE UPPER LEVEL TROUGH ON TRACK TO ADVECT THROUGH THE
REGION SAT-SUN...WITH A WEAKER SHORTWAVE IMPULSE POSSIBLE MONDAY.
TROUGH RELOADING OVER THE NE PAC TUE-WED FAVORED IN ECMWF/GFS
SOLUTIONS...WHICH WOULD SUPPORT MEAN RIDGING OVER THE NORTHERN
PLAINS WITH DRY AND WARMER CONDITIONS. MAIN FORECAST TREND IS A
QUICKER ARRIVAL OF THE EXPECTED LONG WAVE TROUGH SAT...WITH PRECIP
CHANCES INCREASING SAT AFTERNOON WESTERN THIRD. OTHERWISE...THE
REMAINDER OF THE FORECAST IS ON TRACK ATTM.

UPPER LEVEL TROUGH WILL PUSH OUT OF THE NE PAC AND INTO THE NORTHERN
PLAINS...SUPPORTING INCREASING LSA SAT THROUGH SUNDAY. LEE SIDE SFC
TROUGH WILL WILL INTERACT WITH THE APPROACHING UPPER WAVE SUPPORTING
A FOCUS FOR SHRA/TS ACTIVITY OVER THE WESTERN FA BY SAT AFTERNOON.
LL SE FLOW AHEAD OF THIS SYSTEM WITH MOIST UPPER LEVEL SW FLOW WILL
SUPPORT INCREASING PW OVER THE REGION...WITH PLENTY OF MOISTURE
BEING AVAILABLE WITH THIS SYSTEM. SOME MODEL INDICATION FOR
SUFFICIENT DEEP LAYER SHEAR AND CAPE OVER THE FAR NW ZONES...ESP NW
SD BY SAT EVENING...SUPPORTING A POSSIBLE SEVERE THREAT THERE.
SOMETHING TO WATCH. HAVE ADJUSTED POPS UP SAT AFTERNOON AND SAT
EVENING...WITH THE PRIMARY SOUTHERN PERIPHERY IMPULSE EXPECTED TO
SHIFT NE ACROSS THE NW FA. TRAILING SFC TROUGH WITH SUFFICIENT LSA
SHOULD SUPPORT A GOOD CHANCE OF SHRA/TS NW THIRD...WITH MORE
SCT/ISOLD ACTIVITY ACROSS THE REMAINDER OF THE FA. UPPER LEVEL COLD
POOL WILL SUPPORT STEEP LL LAPSE RATES OVER THE FA SUNDAY WITH
RESIDUAL LL MOISTURE IN PLACE. DIURNAL HEATING COUPLED WITH BH/NE WY
TERRAIN INFLUENCES SHOULD SUPPORT SCT TO ISOLD SHRA/TS SW HALF OF
THE FA. BUMPED POPS UP OVER THE BH. OTHERWISE...ONE MORE WEAKER
WESTERLY FLOW IMPULSE STILL INDICATED IN FORECAST MODELS
MONDAY...POSSIBLY SUPPORTING A FEW SHRA/TS...ALTHOUGH UPPER LEVEL
SUPPORT LOOKS MARGINAL ATTM...ESP WITH DRY PROFILES. DRY CONDS
EXPECTED TUE-WED WITH MEAN DEEP LAYER RIDGING.

SEASONAL TEMPS EXPECTED IN MOST OF THE PERIOD...WITH BELOW NORMAL
TEMPS /5-10 DEGREES/ EXPECTED SUNDAY THROUGH MONDAY...ESP NW AREAS.
THE WARMEST DAY IN PERIOD LOOKS TO BE SAT...ESP ON THE SD PLAINS.
ALTHOUGH THERE IS SOME INDICATION FOR WARM CONDITIONS NEXT WED GIVEN
SW WAA FLOW AHEAD OF THE NEXT POTENTIAL EJECTING NE PAC UPPER
TROUGH.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 517 AM MDT THU AUG 28 2014

UPPER LEVEL IMPULSE AND ASSOCIATED RAINS WILL WANE AND SHIFT EAST
THROUGH AFTERNOON...AFFECTING MAINLY THE FAR EASTERN FA...ESP
SCENTRAL SD. MVFR/IFR/LOCAL LIFR CONDS CAN BE EXPECTED THERE. ANY
IFR/LIFR CONDS WILL LIKELY TREND TO MVFR THROUGH AFTERNOON. VFR
CONDS EXPECTED ELSEWHERE. MVFR/IFR CONDS EXPECTED TO REDEVELOP ON
THE SD PLAINS OVERNIGHT /ESP CENTRAL SD/...WITH LCL LIFR/VLIFR CONDS
POSSIBLE IN FOG. NOT EXPECTING RESTRICTIONS AT KRAP OR KGCC
TONIGHT. CONDITIONS WILL SLOWLY IMPROVE LATE FRIDAY MORNING.

&&

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

$$

SHORT TERM...MLS
LONG TERM...JC
AVIATION...JC







000
FXUS63 KUNR 281131
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
531 AM MDT THU AUG 28 2014

.SHORT TERM...TODAY THROUGH FRIDAY NIGHT
ISSUED AT 302 AM MDT THU AUG 28 2014

CURRENT SURFACE ANALYSIS SHOWS LOW PRESSURE OVER SASKATCHEWAN...WITH
A FRONTAL BOUNDARY EXTENDING THROUGH EASTERN MONTANA AND CENTRAL
WYOMING. UPPER LEVEL ANALYSIS SHOWS MAIN LOW PRESSURE AREA OVER NRN
COLORADO/SRN WYOMING WITH A TROF COVERING THE ROCKIES AND HIGH
PLAINS. LATEST RADAR IMAGERY SHOWS SHOWERS CONTINUING TO ROTATE AND
LIFT NORTH ACROSS THE SD PLAINS. A LITTLE EMBEDDED CONVECTION IS ALSO
OCCURRING IN SOUTH CENTRAL SD.

AS THE UPPER LOW MOVES SLOWLY EAST INTO THE CENTRAL HIGH PLAINS...
SHOWER/THUNDERSTORM ACTIVITY WILL QUICKLY DECREASE FROM WEST TO
EAST...WITH SHOWERS/STORMS CONTINUING ACROSS MUCH OF SOUTH CENTRAL
SOUTH DAKOTA. WITH A LOT OF LOW LEVEL MOISTURE AROUND...EXPECT
AREAS OF FOG TO LINGER INTO THE MORNING HOURS ACROSS MOST OF THE
WRN SD PLAINS. BY THIS AFTERNOON...DIURNAL HEATING AND LINGERING
INSTABILITY COULD PRODUCE A TERRAIN INDUCED SHOWER/STORM OVER THE
BLACK HILLS. THUS LEFT ISOLD POPS IN THE FORECAST. TEMPS TODAY
WILL BE WARMER WITH DECREASING CLOUDS...ESPECIALLY ACROSS THE NRN
AND WRN AREAS.

FOR TONIGHT...CLOUDS WILL CONTINUE TO GRADUALLY DECREASE FROM
NORTHWEST TO SOUTHEAST...WITH MOSTLY CLEAR SKIES OVERNIGHT. THIS
COMBINED WITH LIGHT WINDS AND SURFACE HIGH PRESSURE TO THE
WEST...DECIDED TO ADD SOME FOG FOR THE SD PLAINS. TEMPS WILL BE
NEAR NORMAL.

ON FRIDAY...SHORTWAVE TROF MOVES RAPIDLY ACROSS MT/ND PUSHING A WEAK
COOL FRONT INTO WESTERN SD. FORECAST SOUNDINGS SUPPORT 250-500J/KG
MLCAPE...WITH SUFFICIENT LOW LEVEL MOISTURE/CAPE/SHEAR FOR STORMS.
MOST OF THE 500-700MB MOISTURE REMAINS NORTH OF THE CWA...HOWEVER
COULD SEE SCATTERED STORMS WITH AN ISOLATED STRONG STORM ACROSS
NORTHWEST HALF OF CWA. TEMPERATURES ON FRIDAY WILL BE A LITTLE
COOLER THAN TODAY IN THE NW...BUT MOST AREAS WILL SEE WARMER
TEMPERATURES.

&&

.LONG TERM...SATURDAY THROUGH WEDNESDAY
ISSUED AT 302 AM MDT THU AUG 28 2014

PROGRESSIVE NORTHERN STREAM FLOW WILL CONTINUE THROUGH THE PERIOD
WITH A LONG WAVE UPPER LEVEL TROUGH ON TRACK TO ADVECT THROUGH THE
REGION SAT-SUN...WITH A WEAKER SHORTWAVE IMPULSE POSSIBLE MONDAY.
TROUGH RELOADING OVER THE NE PAC TUE-WED FAVORED IN ECMWF/GFS
SOLUTIONS...WHICH WOULD SUPPORT MEAN RIDGING OVER THE NORTHERN
PLAINS WITH DRY AND WARMER CONDITIONS. MAIN FORECAST TREND IS A
QUICKER ARRIVAL OF THE EXPECTED LONG WAVE TROUGH SAT...WITH PRECIP
CHANCES INCREASING SAT AFTERNOON WESTERN THIRD. OTHERWISE...THE
REMAINDER OF THE FORECAST IS ON TRACK ATTM.

UPPER LEVEL TROUGH WILL PUSH OUT OF THE NE PAC AND INTO THE NORTHERN
PLAINS...SUPPORTING INCREASING LSA SAT THROUGH SUNDAY. LEE SIDE SFC
TROUGH WILL WILL INTERACT WITH THE APPROACHING UPPER WAVE SUPPORTING
A FOCUS FOR SHRA/TS ACTIVITY OVER THE WESTERN FA BY SAT AFTERNOON.
LL SE FLOW AHEAD OF THIS SYSTEM WITH MOIST UPPER LEVEL SW FLOW WILL
SUPPORT INCREASING PW OVER THE REGION...WITH PLENTY OF MOISTURE
BEING AVAILABLE WITH THIS SYSTEM. SOME MODEL INDICATION FOR
SUFFICIENT DEEP LAYER SHEAR AND CAPE OVER THE FAR NW ZONES...ESP NW
SD BY SAT EVENING...SUPPORTING A POSSIBLE SEVERE THREAT THERE.
SOMETHING TO WATCH. HAVE ADJUSTED POPS UP SAT AFTERNOON AND SAT
EVENING...WITH THE PRIMARY SOUTHERN PERIPHERY IMPULSE EXPECTED TO
SHIFT NE ACROSS THE NW FA. TRAILING SFC TROUGH WITH SUFFICIENT LSA
SHOULD SUPPORT A GOOD CHANCE OF SHRA/TS NW THIRD...WITH MORE
SCT/ISOLD ACTIVITY ACROSS THE REMAINDER OF THE FA. UPPER LEVEL COLD
POOL WILL SUPPORT STEEP LL LAPSE RATES OVER THE FA SUNDAY WITH
RESIDUAL LL MOISTURE IN PLACE. DIURNAL HEATING COUPLED WITH BH/NE WY
TERRAIN INFLUENCES SHOULD SUPPORT SCT TO ISOLD SHRA/TS SW HALF OF
THE FA. BUMPED POPS UP OVER THE BH. OTHERWISE...ONE MORE WEAKER
WESTERLY FLOW IMPULSE STILL INDICATED IN FORECAST MODELS
MONDAY...POSSIBLY SUPPORTING A FEW SHRA/TS...ALTHOUGH UPPER LEVEL
SUPPORT LOOKS MARGINAL ATTM...ESP WITH DRY PROFILES. DRY CONDS
EXPECTED TUE-WED WITH MEAN DEEP LAYER RIDGING.

SEASONAL TEMPS EXPECTED IN MOST OF THE PERIOD...WITH BELOW NORMAL
TEMPS /5-10 DEGREES/ EXPECTED SUNDAY THROUGH MONDAY...ESP NW AREAS.
THE WARMEST DAY IN PERIOD LOOKS TO BE SAT...ESP ON THE SD PLAINS.
ALTHOUGH THERE IS SOME INDICATION FOR WARM CONDITIONS NEXT WED GIVEN
SW WAA FLOW AHEAD OF THE NEXT POTENTIAL EJECTING NE PAC UPPER
TROUGH.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 517 AM MDT THU AUG 28 2014

UPPER LEVEL IMPULSE AND ASSOCIATED RAINS WILL WANE AND SHIFT EAST
THROUGH AFTERNOON...AFFECTING MAINLY THE FAR EASTERN FA...ESP
SCENTRAL SD. MVFR/IFR/LOCAL LIFR CONDS CAN BE EXPECTED THERE. ANY
IFR/LIFR CONDS WILL LIKELY TREND TO MVFR THROUGH AFTERNOON. VFR
CONDS EXPECTED ELSEWHERE. MVFR/IFR CONDS EXPECTED TO REDEVELOP ON
THE SD PLAINS OVERNIGHT /ESP CENTRAL SD/...WITH LCL LIFR/VLIFR CONDS
POSSIBLE IN FOG. NOT EXPECTING RESTRICTIONS AT KRAP OR KGCC
TONIGHT. CONDITIONS WILL SLOWLY IMPROVE LATE FRIDAY MORNING.

&&

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

$$

SHORT TERM...MLS
LONG TERM...JC
AVIATION...JC







000
FXUS63 KUNR 281131
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
531 AM MDT THU AUG 28 2014

.SHORT TERM...TODAY THROUGH FRIDAY NIGHT
ISSUED AT 302 AM MDT THU AUG 28 2014

CURRENT SURFACE ANALYSIS SHOWS LOW PRESSURE OVER SASKATCHEWAN...WITH
A FRONTAL BOUNDARY EXTENDING THROUGH EASTERN MONTANA AND CENTRAL
WYOMING. UPPER LEVEL ANALYSIS SHOWS MAIN LOW PRESSURE AREA OVER NRN
COLORADO/SRN WYOMING WITH A TROF COVERING THE ROCKIES AND HIGH
PLAINS. LATEST RADAR IMAGERY SHOWS SHOWERS CONTINUING TO ROTATE AND
LIFT NORTH ACROSS THE SD PLAINS. A LITTLE EMBEDDED CONVECTION IS ALSO
OCCURRING IN SOUTH CENTRAL SD.

AS THE UPPER LOW MOVES SLOWLY EAST INTO THE CENTRAL HIGH PLAINS...
SHOWER/THUNDERSTORM ACTIVITY WILL QUICKLY DECREASE FROM WEST TO
EAST...WITH SHOWERS/STORMS CONTINUING ACROSS MUCH OF SOUTH CENTRAL
SOUTH DAKOTA. WITH A LOT OF LOW LEVEL MOISTURE AROUND...EXPECT
AREAS OF FOG TO LINGER INTO THE MORNING HOURS ACROSS MOST OF THE
WRN SD PLAINS. BY THIS AFTERNOON...DIURNAL HEATING AND LINGERING
INSTABILITY COULD PRODUCE A TERRAIN INDUCED SHOWER/STORM OVER THE
BLACK HILLS. THUS LEFT ISOLD POPS IN THE FORECAST. TEMPS TODAY
WILL BE WARMER WITH DECREASING CLOUDS...ESPECIALLY ACROSS THE NRN
AND WRN AREAS.

FOR TONIGHT...CLOUDS WILL CONTINUE TO GRADUALLY DECREASE FROM
NORTHWEST TO SOUTHEAST...WITH MOSTLY CLEAR SKIES OVERNIGHT. THIS
COMBINED WITH LIGHT WINDS AND SURFACE HIGH PRESSURE TO THE
WEST...DECIDED TO ADD SOME FOG FOR THE SD PLAINS. TEMPS WILL BE
NEAR NORMAL.

ON FRIDAY...SHORTWAVE TROF MOVES RAPIDLY ACROSS MT/ND PUSHING A WEAK
COOL FRONT INTO WESTERN SD. FORECAST SOUNDINGS SUPPORT 250-500J/KG
MLCAPE...WITH SUFFICIENT LOW LEVEL MOISTURE/CAPE/SHEAR FOR STORMS.
MOST OF THE 500-700MB MOISTURE REMAINS NORTH OF THE CWA...HOWEVER
COULD SEE SCATTERED STORMS WITH AN ISOLATED STRONG STORM ACROSS
NORTHWEST HALF OF CWA. TEMPERATURES ON FRIDAY WILL BE A LITTLE
COOLER THAN TODAY IN THE NW...BUT MOST AREAS WILL SEE WARMER
TEMPERATURES.

&&

.LONG TERM...SATURDAY THROUGH WEDNESDAY
ISSUED AT 302 AM MDT THU AUG 28 2014

PROGRESSIVE NORTHERN STREAM FLOW WILL CONTINUE THROUGH THE PERIOD
WITH A LONG WAVE UPPER LEVEL TROUGH ON TRACK TO ADVECT THROUGH THE
REGION SAT-SUN...WITH A WEAKER SHORTWAVE IMPULSE POSSIBLE MONDAY.
TROUGH RELOADING OVER THE NE PAC TUE-WED FAVORED IN ECMWF/GFS
SOLUTIONS...WHICH WOULD SUPPORT MEAN RIDGING OVER THE NORTHERN
PLAINS WITH DRY AND WARMER CONDITIONS. MAIN FORECAST TREND IS A
QUICKER ARRIVAL OF THE EXPECTED LONG WAVE TROUGH SAT...WITH PRECIP
CHANCES INCREASING SAT AFTERNOON WESTERN THIRD. OTHERWISE...THE
REMAINDER OF THE FORECAST IS ON TRACK ATTM.

UPPER LEVEL TROUGH WILL PUSH OUT OF THE NE PAC AND INTO THE NORTHERN
PLAINS...SUPPORTING INCREASING LSA SAT THROUGH SUNDAY. LEE SIDE SFC
TROUGH WILL WILL INTERACT WITH THE APPROACHING UPPER WAVE SUPPORTING
A FOCUS FOR SHRA/TS ACTIVITY OVER THE WESTERN FA BY SAT AFTERNOON.
LL SE FLOW AHEAD OF THIS SYSTEM WITH MOIST UPPER LEVEL SW FLOW WILL
SUPPORT INCREASING PW OVER THE REGION...WITH PLENTY OF MOISTURE
BEING AVAILABLE WITH THIS SYSTEM. SOME MODEL INDICATION FOR
SUFFICIENT DEEP LAYER SHEAR AND CAPE OVER THE FAR NW ZONES...ESP NW
SD BY SAT EVENING...SUPPORTING A POSSIBLE SEVERE THREAT THERE.
SOMETHING TO WATCH. HAVE ADJUSTED POPS UP SAT AFTERNOON AND SAT
EVENING...WITH THE PRIMARY SOUTHERN PERIPHERY IMPULSE EXPECTED TO
SHIFT NE ACROSS THE NW FA. TRAILING SFC TROUGH WITH SUFFICIENT LSA
SHOULD SUPPORT A GOOD CHANCE OF SHRA/TS NW THIRD...WITH MORE
SCT/ISOLD ACTIVITY ACROSS THE REMAINDER OF THE FA. UPPER LEVEL COLD
POOL WILL SUPPORT STEEP LL LAPSE RATES OVER THE FA SUNDAY WITH
RESIDUAL LL MOISTURE IN PLACE. DIURNAL HEATING COUPLED WITH BH/NE WY
TERRAIN INFLUENCES SHOULD SUPPORT SCT TO ISOLD SHRA/TS SW HALF OF
THE FA. BUMPED POPS UP OVER THE BH. OTHERWISE...ONE MORE WEAKER
WESTERLY FLOW IMPULSE STILL INDICATED IN FORECAST MODELS
MONDAY...POSSIBLY SUPPORTING A FEW SHRA/TS...ALTHOUGH UPPER LEVEL
SUPPORT LOOKS MARGINAL ATTM...ESP WITH DRY PROFILES. DRY CONDS
EXPECTED TUE-WED WITH MEAN DEEP LAYER RIDGING.

SEASONAL TEMPS EXPECTED IN MOST OF THE PERIOD...WITH BELOW NORMAL
TEMPS /5-10 DEGREES/ EXPECTED SUNDAY THROUGH MONDAY...ESP NW AREAS.
THE WARMEST DAY IN PERIOD LOOKS TO BE SAT...ESP ON THE SD PLAINS.
ALTHOUGH THERE IS SOME INDICATION FOR WARM CONDITIONS NEXT WED GIVEN
SW WAA FLOW AHEAD OF THE NEXT POTENTIAL EJECTING NE PAC UPPER
TROUGH.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 517 AM MDT THU AUG 28 2014

UPPER LEVEL IMPULSE AND ASSOCIATED RAINS WILL WANE AND SHIFT EAST
THROUGH AFTERNOON...AFFECTING MAINLY THE FAR EASTERN FA...ESP
SCENTRAL SD. MVFR/IFR/LOCAL LIFR CONDS CAN BE EXPECTED THERE. ANY
IFR/LIFR CONDS WILL LIKELY TREND TO MVFR THROUGH AFTERNOON. VFR
CONDS EXPECTED ELSEWHERE. MVFR/IFR CONDS EXPECTED TO REDEVELOP ON
THE SD PLAINS OVERNIGHT /ESP CENTRAL SD/...WITH LCL LIFR/VLIFR CONDS
POSSIBLE IN FOG. NOT EXPECTING RESTRICTIONS AT KRAP OR KGCC
TONIGHT. CONDITIONS WILL SLOWLY IMPROVE LATE FRIDAY MORNING.

&&

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

$$

SHORT TERM...MLS
LONG TERM...JC
AVIATION...JC







000
FXUS65 KCYS 281026
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
426 AM MDT THU AUG 28 2014

.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 425 AM MDT THU AUG 28 2014

PREDAWN WATER VAPOR IMAGERY SHOWED THE UPPER LOW OVER SOUTHERN WY/NORTHERN
CO. AT THE SURFACE...A FRONT EXTENDED FROM THE MID-ATLANTIC REGION ACROSS
THE TN VALLEY TO A LOW ALONG THE CENTRAL NE/KS BORDER THEN SOUTHWEST
TO ANOTHER LOW IN SOUTHEAST CO. A LARGE CLUSTER OF STRONG CONVECTION
DEVELOPED ALONG AND JUST NORTH OF THE FRONT OVER SOUTH CENTRAL/SOUTHEAST
NE. LIGHT SHOWERS WERE DEVELOPING AND MOVING SOUTHWEST FROM EAST CENTRAL
TO SOUTH CENTRAL WY.

THE 00Z CONSENSUS MODEL GUIDANCE WEAKENS THE UPPER LOW TO AN OPEN WAVE
THIS MORNING OVER THE HIGH PLAINS...PROGRESSING SLOWLY EAST INTO THE
CENTRAL GREAT PLAINS FRIDAY. CONVECTIVE COVERAGE TODAY WILL BE LESS
THAN THE PAST FEW DAYS WITH THE RISK FOR HEAVY RAINFALL FROM THE CENTRAL
PLAINS TO THE UPPER MS VALLEY. WRAPAROUND MOISTURE OVER NORTHERN AND
WESTERN PORTIONS OF THE CWA THIS MORNING WILL GRADUALLY SLIDE EAST
THIS AFTERNOON AND EARLY EVENING. THERE WILL BE ENOUGH INSTABILITY FROM
DAYTIME HEATING FOR SCATTERED SHOWERS/TSTORMS THIS AFTERNOON...ESPECIALLY
SOUTH OF A RAWLINS WY TO ALLIANCE NE LINE. HIGH TEMPERATURES TODAY WILL
BE SLIGHTLY WARMER WITH 70S FOR LOWER ELEVATIONS.

A FEW LINGERING SHOWERS OR TSTORMS OVER THE EXTREME SOUTHERN NE PANHANDLE
EARLY THIS EVENING. OTHERWISE...SUBSIDENCE AND DRIER MORE STABLE AIRMASS
WILL SPREAD WEST TO EAST WITH THE APPROACH AND PASSAGE OF A SHORTWAVE
RIDGE.

A WEAK SHORTWAVE OVER THE NORTHERN ROCKIES EARLY FRIDAY MORNING MAKES
A BEELINE FOR THE NORTHERN HIGH PLAINS FRIDAY AFTERNOON. MOISTURE WILL
BE LIMITED WITH MARGINAL INSTABILITY FOR ISOLATED AFTERNOON TSTORMS
OVER THE MOUNTAINS AND NEARBY PLAINS OF SOUTHEAST WY. HIGH TEMPERATURES
WILL WARM INTO THE 80S EAST OF THE LARAMIE RANGE...WITH 60S AND 70S
WEST. EXPECT TRANQUIL CONDITIONS FRIDAY NIGHT WITH THE PASSAGE OF
ANOTHER SHORTWAVE RIDGE.

LATEST MODELS CONTINUE TO DEPICT A MORE SIGNIFICANT UPPER TROUGH TAKING
SHAPE OVER THE GREAT BASIN AND PACIFIC NORTHWEST SATURDAY. A RATHER
STRONG PACIFIC COLD FRONT WILL BE MOVING THROUGH NORTHERN AND WESTERN
WY DURING THE AFTERNOON. 700MB WINDS INCREASE TO 35 KT FROM THE WEST
AND SOUTHWEST. PACIFIC MOISTURE WILL ALSO INCREASE BY LATE AFTERNOON
WITH WIDELY SCATTERED SHOWERS/TSTORMS DEVELOPING ALONG AND WEST OF A
CHADRON NE TO CHEYENNE WY LINE. A TIGHTER SURFACE PRESSURE GRADIENT
WILL CREATE RATHER BREEZY WEST TO SOUTHWEST WINDS. IT WILL BE A WARM
AFTERNOON WITH HIGHS IN THE 80S TO LOWER 90S FOR THE PLAINS...WITH 60S
AND 70S WEST.

.LONG TERM...(SATURDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 350 AM MDT THU AUG 28 2014

MEDIUM AND LONG RANGE MODELS IN GOOD AGREEMENT INTO EARLY NEXT WEEK.
THE MAIN FORECAST CONCERN WILL BE A BROAD UPPER LEVEL TROUGH AND
ASSOCIATED COLD FRONT FOR LATER THIS WEEKEND. THE COLD FRONT APPEARS
TO BE RATHER STRONG FOR THIS TIME OF THE YEAR...WITH GUSTY WINDS
POSSIBLE ALONG WITH RAIN SHOWERS/TSTORMS OVER MOST OF THE AREA.
CANNOT RULE OUT SOME SNOWFALL ACROSS THE HIGH MOUNTAINS AS THIS FRONT
MOVES ACROSS THE AREA SATURDAY NIGHT AND INTO EARLY SUNDAY. MODELS
IN GOOD AGREEMENT WITH THE TIMING...ALTHOUGH THE GFS IS NOTICEABLY
MORE PROGRESSIVE AND DRIER. PREFER THE ECMWF AND GEM AT THIS TIME
SINCE BOTH THESE MODELS DID BETTER WITH THIS LAST STORM SYSTEM 3
DAYS OUT IN TERMS OF TIMING AND EVOLUTION. INCREASED POP ABOVE 30
PERCENT ACROSS MOST OF THE FORECAST AREA FOR SCATTERED SHOWERS AND
ISOLATED TSTORMS. INCREASED WINDS AS WELL...ALTHOUGH MODEL
SOUNDINGS ARE SUGGESTING SUSTAINED WESTERLY WINDS BETWEEN 20 TO 30
MPH AND GUSTS AROUND 40 MPH. DID NOT INCREASE WINDS QUITE THAT
HIGH SINCE THE ECMWF SHOWS MUCH LOWER WIND SPEEDS SUNDAY AFTERNOON.
TEMPERATURES WILL REMAIN ON THE COOL SIDE AND GENERALLY IN THE
UPPER 60S TO UPPER 70S...WARMEST ACROSS THE NEBRASKA PANHANDLE.

MODELS THEN INDICATE A DRYING TREND FOR NEXT WEEK AS THE SOUTHWESTERN
MONSOON MAY BE ENDING...WHICH IS TYPICAL IN THE LATE SUMMER. MODELS
AND ENSEMBLES ALSO SHOW WHAT APPEARS TO BE A TRANSITIONAL PERIOD IN
THE PATTERN...AS THE POLAR JET STREAM BECOMES MORE DEFINED BY DAY
6 AND 7 NEAR THE CANADIAN BORDER. THIS WILL RESULT IN QUASI-ZONAL
FLOW OVER THE WESTERN TWO THIRDS OF THE UNITED STATES. HOWEVER...THE
ECMWF AND GEM DO SHOW AN UPPER LEVEL DISTURBANCE MOVING SOUTHEAST
ACROSS THE HIGH PLAINS LATE ON MONDAY...SO KEPT LOW POP OVER EAST
CENTRAL WYOMING AND NORTHWEST NEBRASKA. OTHERWISE...TEMPERATURES
WILL GRADUALLY INCREASE TO AROUND NORMAL FOR THIS TIME OF THE YEAR
WITH HIGHS AROUND 80 ALONG AND WEST OF THE LARAMIE RANGE AND RANGING
FROM THE LOW 80S TO THE LOW 90S ACROSS THE HIGH PLAINS EAST OF THE
LARAMIE RANGE BY WEDNESDAY AFTERNOON.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH LATE TONIGHT)
ISSUED AT 350 AM MDT THU AUG 28 2014

LOW CIGS WILL PERSIST EARLY THIS MORNING ACROSS MAINLY THE WESTERN
NEBRASKA PANHANDLE TERMINALS. FOG IS UNLIKELY AT THIS TIME DUE TO
CLOUD COVER. FOG AND LOW CIGS WILL LIFT BY MID MORNING WITH VFR
PREVAILING THROUGH NOON. THE NEXT BAND OF SHOWERS WILL DEVELOP AND
GROW IN COVERAGE EARLY THIS MORNING FROM RAWLINS TO LARAMIE. THIS
BAND WILL INTENSIFY AS THE UPPER LEVEL LOW GRADUALLY DRIFTS ACROSS
NORTHEAST COLORADO. THIS BAND OF RAINFALL AND EMBEDDED TSTORMS
WILL RESULT IN LOCALIZED MVFR CONDITIONS SOUTHEAST OF A KLAR TO
KCDR LINE BY LATE THIS MORNING AND INTO THIS AFTERNOON.

&&

.FIRE WEATHER...
ISSUED AT 255 AM MDT THU AUG 28 2014

THE UPPER LOW PRESSURE SYSTEM RESPONSIBLE FOR THE INCLEMENT WEATHER
THE PAST FEW DAYS WILL MOVE EAST FROM THE CENTRAL ROCKIES TODAY TO
THE CENTRAL GREAT PLAINS FRIDAY. A MORE SCATTERED COVERAGE OF SHOWERS
AND THUNDERSTORMS IS EXPECTED TODAY. MAINLY DRIER AND WARMER CONDITIONS
ARE FORECAST FOR FRIDAY WITH JUST A SLIGHT CHANCE OF AFTERNOON
THUNDERSTORMS OVER THE MOUNTAINS AND PORTIONS OF EAST CENTRAL WYOMING
WITH THE PASSAGE OF A WEAK UPPER LEVEL DISTURBANCE. ISOLATED TO
SCATTERED MAINLY AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS ARE
FORECAST SATURDAY AND SUNDAY AS A MORE SIGNIFICANT UPPER TROUGH AND
COLD FRONT AFFECT THE DISTRICTS. WARM TEMPERATURES SATURDAY WILL TURN
COOLER SUNDAY FOLLOWING THE COLD FRONTAL PASSAGE. THE TIGHT PRESSURE
GRADIENT WILL RESULT IN GUSTY WESTERLY WINDS THIS WEEKEND.

&&

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

$$

SHORT TERM...JAMSKI
LONG TERM...TJT
AVIATION...TJT
FIRE WEATHER...JAMSKI






000
FXUS65 KCYS 281026
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
426 AM MDT THU AUG 28 2014

.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 425 AM MDT THU AUG 28 2014

PREDAWN WATER VAPOR IMAGERY SHOWED THE UPPER LOW OVER SOUTHERN WY/NORTHERN
CO. AT THE SURFACE...A FRONT EXTENDED FROM THE MID-ATLANTIC REGION ACROSS
THE TN VALLEY TO A LOW ALONG THE CENTRAL NE/KS BORDER THEN SOUTHWEST
TO ANOTHER LOW IN SOUTHEAST CO. A LARGE CLUSTER OF STRONG CONVECTION
DEVELOPED ALONG AND JUST NORTH OF THE FRONT OVER SOUTH CENTRAL/SOUTHEAST
NE. LIGHT SHOWERS WERE DEVELOPING AND MOVING SOUTHWEST FROM EAST CENTRAL
TO SOUTH CENTRAL WY.

THE 00Z CONSENSUS MODEL GUIDANCE WEAKENS THE UPPER LOW TO AN OPEN WAVE
THIS MORNING OVER THE HIGH PLAINS...PROGRESSING SLOWLY EAST INTO THE
CENTRAL GREAT PLAINS FRIDAY. CONVECTIVE COVERAGE TODAY WILL BE LESS
THAN THE PAST FEW DAYS WITH THE RISK FOR HEAVY RAINFALL FROM THE CENTRAL
PLAINS TO THE UPPER MS VALLEY. WRAPAROUND MOISTURE OVER NORTHERN AND
WESTERN PORTIONS OF THE CWA THIS MORNING WILL GRADUALLY SLIDE EAST
THIS AFTERNOON AND EARLY EVENING. THERE WILL BE ENOUGH INSTABILITY FROM
DAYTIME HEATING FOR SCATTERED SHOWERS/TSTORMS THIS AFTERNOON...ESPECIALLY
SOUTH OF A RAWLINS WY TO ALLIANCE NE LINE. HIGH TEMPERATURES TODAY WILL
BE SLIGHTLY WARMER WITH 70S FOR LOWER ELEVATIONS.

A FEW LINGERING SHOWERS OR TSTORMS OVER THE EXTREME SOUTHERN NE PANHANDLE
EARLY THIS EVENING. OTHERWISE...SUBSIDENCE AND DRIER MORE STABLE AIRMASS
WILL SPREAD WEST TO EAST WITH THE APPROACH AND PASSAGE OF A SHORTWAVE
RIDGE.

A WEAK SHORTWAVE OVER THE NORTHERN ROCKIES EARLY FRIDAY MORNING MAKES
A BEELINE FOR THE NORTHERN HIGH PLAINS FRIDAY AFTERNOON. MOISTURE WILL
BE LIMITED WITH MARGINAL INSTABILITY FOR ISOLATED AFTERNOON TSTORMS
OVER THE MOUNTAINS AND NEARBY PLAINS OF SOUTHEAST WY. HIGH TEMPERATURES
WILL WARM INTO THE 80S EAST OF THE LARAMIE RANGE...WITH 60S AND 70S
WEST. EXPECT TRANQUIL CONDITIONS FRIDAY NIGHT WITH THE PASSAGE OF
ANOTHER SHORTWAVE RIDGE.

LATEST MODELS CONTINUE TO DEPICT A MORE SIGNIFICANT UPPER TROUGH TAKING
SHAPE OVER THE GREAT BASIN AND PACIFIC NORTHWEST SATURDAY. A RATHER
STRONG PACIFIC COLD FRONT WILL BE MOVING THROUGH NORTHERN AND WESTERN
WY DURING THE AFTERNOON. 700MB WINDS INCREASE TO 35 KT FROM THE WEST
AND SOUTHWEST. PACIFIC MOISTURE WILL ALSO INCREASE BY LATE AFTERNOON
WITH WIDELY SCATTERED SHOWERS/TSTORMS DEVELOPING ALONG AND WEST OF A
CHADRON NE TO CHEYENNE WY LINE. A TIGHTER SURFACE PRESSURE GRADIENT
WILL CREATE RATHER BREEZY WEST TO SOUTHWEST WINDS. IT WILL BE A WARM
AFTERNOON WITH HIGHS IN THE 80S TO LOWER 90S FOR THE PLAINS...WITH 60S
AND 70S WEST.

.LONG TERM...(SATURDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 350 AM MDT THU AUG 28 2014

MEDIUM AND LONG RANGE MODELS IN GOOD AGREEMENT INTO EARLY NEXT WEEK.
THE MAIN FORECAST CONCERN WILL BE A BROAD UPPER LEVEL TROUGH AND
ASSOCIATED COLD FRONT FOR LATER THIS WEEKEND. THE COLD FRONT APPEARS
TO BE RATHER STRONG FOR THIS TIME OF THE YEAR...WITH GUSTY WINDS
POSSIBLE ALONG WITH RAIN SHOWERS/TSTORMS OVER MOST OF THE AREA.
CANNOT RULE OUT SOME SNOWFALL ACROSS THE HIGH MOUNTAINS AS THIS FRONT
MOVES ACROSS THE AREA SATURDAY NIGHT AND INTO EARLY SUNDAY. MODELS
IN GOOD AGREEMENT WITH THE TIMING...ALTHOUGH THE GFS IS NOTICEABLY
MORE PROGRESSIVE AND DRIER. PREFER THE ECMWF AND GEM AT THIS TIME
SINCE BOTH THESE MODELS DID BETTER WITH THIS LAST STORM SYSTEM 3
DAYS OUT IN TERMS OF TIMING AND EVOLUTION. INCREASED POP ABOVE 30
PERCENT ACROSS MOST OF THE FORECAST AREA FOR SCATTERED SHOWERS AND
ISOLATED TSTORMS. INCREASED WINDS AS WELL...ALTHOUGH MODEL
SOUNDINGS ARE SUGGESTING SUSTAINED WESTERLY WINDS BETWEEN 20 TO 30
MPH AND GUSTS AROUND 40 MPH. DID NOT INCREASE WINDS QUITE THAT
HIGH SINCE THE ECMWF SHOWS MUCH LOWER WIND SPEEDS SUNDAY AFTERNOON.
TEMPERATURES WILL REMAIN ON THE COOL SIDE AND GENERALLY IN THE
UPPER 60S TO UPPER 70S...WARMEST ACROSS THE NEBRASKA PANHANDLE.

MODELS THEN INDICATE A DRYING TREND FOR NEXT WEEK AS THE SOUTHWESTERN
MONSOON MAY BE ENDING...WHICH IS TYPICAL IN THE LATE SUMMER. MODELS
AND ENSEMBLES ALSO SHOW WHAT APPEARS TO BE A TRANSITIONAL PERIOD IN
THE PATTERN...AS THE POLAR JET STREAM BECOMES MORE DEFINED BY DAY
6 AND 7 NEAR THE CANADIAN BORDER. THIS WILL RESULT IN QUASI-ZONAL
FLOW OVER THE WESTERN TWO THIRDS OF THE UNITED STATES. HOWEVER...THE
ECMWF AND GEM DO SHOW AN UPPER LEVEL DISTURBANCE MOVING SOUTHEAST
ACROSS THE HIGH PLAINS LATE ON MONDAY...SO KEPT LOW POP OVER EAST
CENTRAL WYOMING AND NORTHWEST NEBRASKA. OTHERWISE...TEMPERATURES
WILL GRADUALLY INCREASE TO AROUND NORMAL FOR THIS TIME OF THE YEAR
WITH HIGHS AROUND 80 ALONG AND WEST OF THE LARAMIE RANGE AND RANGING
FROM THE LOW 80S TO THE LOW 90S ACROSS THE HIGH PLAINS EAST OF THE
LARAMIE RANGE BY WEDNESDAY AFTERNOON.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH LATE TONIGHT)
ISSUED AT 350 AM MDT THU AUG 28 2014

LOW CIGS WILL PERSIST EARLY THIS MORNING ACROSS MAINLY THE WESTERN
NEBRASKA PANHANDLE TERMINALS. FOG IS UNLIKELY AT THIS TIME DUE TO
CLOUD COVER. FOG AND LOW CIGS WILL LIFT BY MID MORNING WITH VFR
PREVAILING THROUGH NOON. THE NEXT BAND OF SHOWERS WILL DEVELOP AND
GROW IN COVERAGE EARLY THIS MORNING FROM RAWLINS TO LARAMIE. THIS
BAND WILL INTENSIFY AS THE UPPER LEVEL LOW GRADUALLY DRIFTS ACROSS
NORTHEAST COLORADO. THIS BAND OF RAINFALL AND EMBEDDED TSTORMS
WILL RESULT IN LOCALIZED MVFR CONDITIONS SOUTHEAST OF A KLAR TO
KCDR LINE BY LATE THIS MORNING AND INTO THIS AFTERNOON.

&&

.FIRE WEATHER...
ISSUED AT 255 AM MDT THU AUG 28 2014

THE UPPER LOW PRESSURE SYSTEM RESPONSIBLE FOR THE INCLEMENT WEATHER
THE PAST FEW DAYS WILL MOVE EAST FROM THE CENTRAL ROCKIES TODAY TO
THE CENTRAL GREAT PLAINS FRIDAY. A MORE SCATTERED COVERAGE OF SHOWERS
AND THUNDERSTORMS IS EXPECTED TODAY. MAINLY DRIER AND WARMER CONDITIONS
ARE FORECAST FOR FRIDAY WITH JUST A SLIGHT CHANCE OF AFTERNOON
THUNDERSTORMS OVER THE MOUNTAINS AND PORTIONS OF EAST CENTRAL WYOMING
WITH THE PASSAGE OF A WEAK UPPER LEVEL DISTURBANCE. ISOLATED TO
SCATTERED MAINLY AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS ARE
FORECAST SATURDAY AND SUNDAY AS A MORE SIGNIFICANT UPPER TROUGH AND
COLD FRONT AFFECT THE DISTRICTS. WARM TEMPERATURES SATURDAY WILL TURN
COOLER SUNDAY FOLLOWING THE COLD FRONTAL PASSAGE. THE TIGHT PRESSURE
GRADIENT WILL RESULT IN GUSTY WESTERLY WINDS THIS WEEKEND.

&&

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

$$

SHORT TERM...JAMSKI
LONG TERM...TJT
AVIATION...TJT
FIRE WEATHER...JAMSKI







000
FXUS65 KRIW 280904
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
304 AM MDT THU AUG 28 2014

.SHORT TERM...TODAY THROUGH SATURDAY NIGHT

LIGHT SHOWERS NOTED ACROSS THE SOUTHEASTERN HALF OF THE FORECAST
AREA THIS MORNING. THE CORE OF THE LOW PRESSURE IS OVER
NORTHEASTERN COLORADO AND IS CONTINUING ON ITS EASTWARD
PROGRESSION. SHOWERS WILL CONTINUE TO TAPER OFF AS THE SYSTEM
MOVES FURTHER EAST...WITH NATRONA AND SWEETWATER COUNTIES LOOKING
TO HOLD ON TO SHOWER ACTIVITY THE LONGEST.

DRY NORTHWEST FLOW BUILDS OVER THE AREA THIS EVENING UNDER THE
INFLUENCE OF A FLATTENED RIDGING PATTERN. THIS SYSTEM WILL ALLOW
SURGES OF MOISTURE TO MOVE INTO THE FORECAST AREA...ESPECIALLY
NORTHWESTERN WYOMING. SHOWERS AND THUNDERSTORMS WILL BE
POSSIBLE...WITH ASSOCIATED THREATS OF GUSTY WIND AND LIGHTNING
ACTIVITY.

ANOTHER TROUGH ADVANCES TOWARDS THE FORECAST AREA BY SATURDAY
MORNING...BRINGING INCREASING SOUTHWEST FLOW OVER THE AREA. GUSTY
WINDS WILL BE POSSIBLE UNDER THIS FLOW...WITH DRIER CONDITIONS NOTED
OVER SOUTHERN WYOMING AHEAD OF THE TROUGH. THIS MAY LEAD TO SOME
ELEVATED FIRE WEATHER CONCERNS...BUT THE SITUATION WILL CONTINUE TO
BE MONITORED.

THE TROUGH WILL STRENGTHEN OVER THE AREA SATURDAY AFTERNOON AND
EVENING...WITH MORE WIDESPREAD SHOWERS AND THUNDERSTORMS
ANTICIPATED. AGAIN...GUSTY WIND AND LIGHTNING WILL BE THE PRIMARY
THREATS WITH STORM ACTIVITY OVER THE NEXT FEW DAYS. THE TROUGH WILL
GENERALLY MOVE THROUGH THE AREA BY SUNDAY MORNING...WITH A RETURN OF
DRY NORTHWEST FLOW.

.LONG TERM...SUNDAY THROUGH WEDNESDAY NIGHT

FAST MOVING FLOW ALOFT DURING MOST OF THE EXTENDED PERIOD WITH A
MID/UPPER LEVEL TROUGH PASSAGE EARLY SUNDAY. MEDIUM RANGE MODELS
GENERALLY HAVE CLOUDS AND MOISTURE EAST OF THE FORECAST AREA BY
SUNDAY AFTERNOON. IN FACT...FAIR WEATHER SHOULD PREVAIL WEST OF
THE DIVIDE ON SUNDAY. THINKING DOWNWARD FORCING BEHIND THIS TROUGH
TO RESULT IN BREEZY TO WINDY CONDITIONS SUNDAY AFTERNOON AND EVENING.

AFTER THIS TIME...FAST ZONAL FLOW OVER WYOMING WITH NEAR NORMAL
TEMPERATURES EXPECTED. MONDAY AND TUESDAY MORNINGS TO START OFF
RELATIVELY COOL. THERE LOOKS TO BE VERY LITTLE SUPPORT ALOFT FOR
PRECIPITATION WITH THIS PATTERN. WILL CALL IT MOSTLY DRY AND
BREEZY THROUGH WEDNESDAY. HOWEVER...CANNOT RULE OUT ISOLATED
SHOWERS OR THUNDERSTORMS EACH DAY ACROSS THE FORECAST AREA.

&&

.AVIATION.../12Z ISSUANCE/

AN UPPER LEVEL LOW PRESSURE SYSTEM WILL CONTINUE TO DRIFT EAST INTO
NE COLORADO EARLY THIS MORNING. PATCHY FOG AND IFR/LIFR CIGS WILL
PARTIALLY OBSCURE TERRAIN VCNTY AND SOUTH OF A KCPR-KRIW-KBPI LINE
UNTIL 14Z.

VFR CONDITIONS WILL THEN PREVAIL ACROSS THE REGION TODAY WITH
SFC-BOUNDARY LAYER WINDS MAINLY OUT OF THE NW AT AROUND 10KTS. A
WEAK UPPER LEVEL DISTURBANCE WILL SPREAD WDLY SCT -SHRA AND ISOLD
-TSRA INTO THE NW MTNS...PRIMARILY NORTH OF A KJAC-KCOD LINE...LATE
THIS AFTERNOON AND EVENING WITH THIS ACTIVITY SPREADING EAST
PRIMARILY VCNTY AND NORTH OF KCOD-KBYG OVERNIGHT WITH CIGS FL120-150.

&&

.FIRE WEATHER...

WEAKENING SHOWERS AND THUNDERSTORMS EXPECTED OVER THE AREA THIS
MORNING...WITH BUILDING DRY WEST TO NORTHWEST FLOW. A FEW SHOWERS
WILL BE POSSIBLE ACROSS THE EXTREME NORTHWEST DURING THE EVENING AND
OVERNIGHT HOURS...WITH DRY CONDITIONS OTHERWISE. AN APPROACHING WAVE
OF LOW PRESSURE WILL TURN THE FLOW TO THE SOUTHWEST LATE FRIDAY AND
INTO SATURDAY. AHEAD OF THE TROUGH AXIS...CONDITIONS ACROSS SOUTHERN
WYOMING COULD BECOME BREEZY AND DRY...RAISING SOME FIRE WEATHER
CONCERNS. THE THREAT WILL BE SHORT LIVED...WITH SHOWERS AND
THUNDERSTORMS ANTICIPATED ACROSS THE AREA BY SATURDAY AFTERNOON.

&&

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

$$

SHORT TERM...BRANHAM
LONG TERM...KPL
AVIATION...KPL
FIRE WEATHER...BRANHAM





000
FXUS63 KUNR 280904
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
304 AM MDT THU AUG 28 2014

.SHORT TERM...TODAY THROUGH FRIDAY NIGHT
ISSUED AT 302 AM MDT THU AUG 28 2014

CURRENT SURFACE ANALYSIS SHOWS LOW PRESSURE OVER SASKATCHEWAN...WITH
A FRONTAL BOUNDARY EXTENDING THROUGH EASTERN MONTANA AND CENTRAL
WYOMING. UPPER LEVEL ANALYSIS SHOWS MAIN LOW PRESSURE AREA OVER NRN
COLORADO/SRN WYOMING WITH A TROF COVERING THE ROCKIES AND HIGH
PLAINS. LATEST RADAR IMAGERY SHOWS SHOWERS CONTINUING TO ROTATE AND
LIFT NORTH ACROSS THE SD PLAINS. A LITTLE EMBEDDED CONVECTION IS ALSO
OCCURRING IN SOUTH CENTRAL SD.

AS THE UPPER LOW MOVES SLOWLY EAST INTO THE CENTRAL HIGH PLAINS...
SHOWER/THUNDERSTORM ACTIVITY WILL QUICKLY DECREASE FROM WEST TO
EAST...WITH SHOWERS/STORMS CONTINUING ACROSS MUCH OF SOUTH CENTRAL
SOUTH DAKOTA. WITH A LOT OF LOW LEVEL MOISTURE AROUND...EXPECT
AREAS OF FOG TO LINGER INTO THE MORNING HOURS ACROSS MOST OF THE
WRN SD PLAINS. BY THIS AFTERNOON...DIURNAL HEATING AND LINGERING
INSTABILITY COULD PRODUCE A TERRAIN INDUCED SHOWER/STORM OVER THE
BLACK HILLS. THUS LEFT ISOLD POPS IN THE FORECAST. TEMPS TODAY
WILL BE WARMER WITH DECREASING CLOUDS...ESPECIALLY ACROSS THE NRN
AND WRN AREAS.

FOR TONIGHT...CLOUDS WILL CONTINUE TO GRADUALLY DECREASE FROM
NORTHWEST TO SOUTHEAST...WITH MOSTLY CLEAR SKIES OVERNIGHT. THIS
COMBINED WITH LIGHT WINDS AND SURFACE HIGH PRESSURE TO THE
WEST...DECIDED TO ADD SOME FOG FOR THE SD PLAINS. TEMPS WILL BE
NEAR NORMAL.

ON FRIDAY...SHORTWAVE TROF MOVES RAPIDLY ACROSS MT/ND PUSHING A WEAK
COOL FRONT INTO WESTERN SD. FORECAST SOUNDINGS SUPPORT 250-500J/KG
MLCAPE...WITH SUFFICIENT LOW LEVEL MOISTURE/CAPE/SHEAR FOR STORMS.
MOST OF THE 500-700MB MOISTURE REMAINS NORTH OF THE CWA...HOWEVER
COULD SEE SCATTERED STORMS WITH AN ISOLATED STRONG STORM ACROSS
NORTHWEST HALF OF CWA. TEMPERATURES ON FRIDAY WILL BE A LITTLE
COOLER THAN TODAY IN THE NW...BUT MOST AREAS WILL SEE WARMER
TEMPERATURES.

&&

.LONG TERM...SATURDAY THROUGH WEDNESDAY
ISSUED AT 302 AM MDT THU AUG 28 2014

PROGRESSIVE NORTHERN STREAM FLOW WILL CONTINUE THROUGH THE PERIOD
WITH A LONG WAVE UPPER LEVEL TROUGH ON TRACK TO ADVECT THROUGH THE
REGION SAT-SUN...WITH A WEAKER SHORTWAVE IMPULSE POSSIBLE MONDAY.
TROUGH RELOADING OVER THE NE PAC TUE-WED FAVORED IN ECMWF/GFS
SOLUTIONS...WHICH WOULD SUPPORT MEAN RIDGING OVER THE NORTHERN
PLAINS WITH DRY AND WARMER CONDITIONS. MAIN FORECAST TREND IS A
QUICKER ARRIVAL OF THE EXPECTED LONG WAVE TROUGH SAT...WITH PRECIP
CHANCES INCREASING SAT AFTERNOON WESTERN THIRD. OTHERWISE...THE
REMAINDER OF THE FORECAST IS ON TRACK ATTM.

UPPER LEVEL TROUGH WILL PUSH OUT OF THE NE PAC AND INTO THE NORTHERN
PLAINS...SUPPORTING INCREASING LSA SAT THROUGH SUNDAY. LEE SIDE SFC
TROUGH WILL WILL INTERACT WITH THE APPROACHING UPPER WAVE SUPPORTING
A FOCUS FOR SHRA/TS ACTIVITY OVER THE WESTERN FA BY SAT AFTERNOON.
LL SE FLOW AHEAD OF THIS SYSTEM WITH MOIST UPPER LEVEL SW FLOW WILL
SUPPORT INCREASING PW OVER THE REGION...WITH PLENTY OF MOISTURE
BEING AVAILABLE WITH THIS SYSTEM. SOME MODEL INDICATION FOR
SUFFICIENT DEEP LAYER SHEAR AND CAPE OVER THE FAR NW ZONES...ESP NW
SD BY SAT EVENING...SUPPORTING A POSSIBLE SEVERE THREAT THERE.
SOMETHING TO WATCH. HAVE ADJUSTED POPS UP SAT AFTERNOON AND SAT
EVENING...WITH THE PRIMARY SOUTHERN PERIPHERY IMPULSE EXPECTED TO
SHIFT NE ACROSS THE NW FA. TRAILING SFC TROUGH WITH SUFFICIENT LSA
SHOULD SUPPORT A GOOD CHANCE OF SHRA/TS NW THIRD...WITH MORE
SCT/ISOLD ACTIVITY ACROSS THE REMAINDER OF THE FA. UPPER LEVEL COLD
POOL WILL SUPPORT STEEP LL LAPSE RATES OVER THE FA SUNDAY WITH
RESIDUAL LL MOISTURE IN PLACE. DIURNAL HEATING COUPLED WITH BH/NE WY
TERRAIN INFLUENCES SHOULD SUPPORT SCT TO ISOLD SHRA/TS SW HALF OF
THE FA. BUMPED POPS UP OVER THE BH. OTHERWISE...ONE MORE WEAKER
WESTERLY FLOW IMPULSE STILL INDICATED IN FORECAST MODELS
MONDAY...POSSIBLY SUPPORTING A FEW SHRA/TS...ALTHOUGH UPPER LEVEL
SUPPORT LOOKS MARGINAL ATTM...ESP WITH DRY PROFILES. DRY CONDS
EXPECTED TUE-WED WITH MEAN DEEP LAYER RIDGING.

SEASONAL TEMPS EXPECTED IN MOST OF THE PERIOD...WITH BELOW NORMAL
TEMPS /5-10 DEGREES/ EXPECTED SUNDAY THROUGH MONDAY...ESP NW AREAS.
THE WARMEST DAY IN PERIOD LOOKS TO BE SAT...ESP ON THE SD PLAINS.
ALTHOUGH THERE IS SOME INDICATION FOR WARM CONDITIONS NEXT WED GIVEN
SW WAA FLOW AHEAD OF THE NEXT POTENTIAL EJECTING NE PAC UPPER
TROUGH.

&&

.AVIATION...FOR THE 12Z TAFS THROUGH 12Z FRIDAY
ISSUED AT 302 AM MDT THU AUG 28 2014

WDSPRD SHRA WILL CONTINUE THIS MORNING...MAINLY CNTRL SD. LOCAL
IFR VSBY IN FOG POSSIBLE THERE...ESP INTO NW SD. THE PCPN WILL
SHIFT EAST OF THE REGION THROUGH TODAY. MVFR CIGS EXPECTED TO
REDEVELOP ON THE PLAINS OF WRN SD OVERNIGHT...WITH LCL IFR CONDS
IN FOG. CONDITIONS WILL SLOWLY IMPROVE ON FRIDAY.

&&

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

$$

SHORT TERM...MLS
LONG TERM...JC
AVIATION...JC







000
FXUS63 KUNR 280904
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
304 AM MDT THU AUG 28 2014

.SHORT TERM...TODAY THROUGH FRIDAY NIGHT
ISSUED AT 302 AM MDT THU AUG 28 2014

CURRENT SURFACE ANALYSIS SHOWS LOW PRESSURE OVER SASKATCHEWAN...WITH
A FRONTAL BOUNDARY EXTENDING THROUGH EASTERN MONTANA AND CENTRAL
WYOMING. UPPER LEVEL ANALYSIS SHOWS MAIN LOW PRESSURE AREA OVER NRN
COLORADO/SRN WYOMING WITH A TROF COVERING THE ROCKIES AND HIGH
PLAINS. LATEST RADAR IMAGERY SHOWS SHOWERS CONTINUING TO ROTATE AND
LIFT NORTH ACROSS THE SD PLAINS. A LITTLE EMBEDDED CONVECTION IS ALSO
OCCURRING IN SOUTH CENTRAL SD.

AS THE UPPER LOW MOVES SLOWLY EAST INTO THE CENTRAL HIGH PLAINS...
SHOWER/THUNDERSTORM ACTIVITY WILL QUICKLY DECREASE FROM WEST TO
EAST...WITH SHOWERS/STORMS CONTINUING ACROSS MUCH OF SOUTH CENTRAL
SOUTH DAKOTA. WITH A LOT OF LOW LEVEL MOISTURE AROUND...EXPECT
AREAS OF FOG TO LINGER INTO THE MORNING HOURS ACROSS MOST OF THE
WRN SD PLAINS. BY THIS AFTERNOON...DIURNAL HEATING AND LINGERING
INSTABILITY COULD PRODUCE A TERRAIN INDUCED SHOWER/STORM OVER THE
BLACK HILLS. THUS LEFT ISOLD POPS IN THE FORECAST. TEMPS TODAY
WILL BE WARMER WITH DECREASING CLOUDS...ESPECIALLY ACROSS THE NRN
AND WRN AREAS.

FOR TONIGHT...CLOUDS WILL CONTINUE TO GRADUALLY DECREASE FROM
NORTHWEST TO SOUTHEAST...WITH MOSTLY CLEAR SKIES OVERNIGHT. THIS
COMBINED WITH LIGHT WINDS AND SURFACE HIGH PRESSURE TO THE
WEST...DECIDED TO ADD SOME FOG FOR THE SD PLAINS. TEMPS WILL BE
NEAR NORMAL.

ON FRIDAY...SHORTWAVE TROF MOVES RAPIDLY ACROSS MT/ND PUSHING A WEAK
COOL FRONT INTO WESTERN SD. FORECAST SOUNDINGS SUPPORT 250-500J/KG
MLCAPE...WITH SUFFICIENT LOW LEVEL MOISTURE/CAPE/SHEAR FOR STORMS.
MOST OF THE 500-700MB MOISTURE REMAINS NORTH OF THE CWA...HOWEVER
COULD SEE SCATTERED STORMS WITH AN ISOLATED STRONG STORM ACROSS
NORTHWEST HALF OF CWA. TEMPERATURES ON FRIDAY WILL BE A LITTLE
COOLER THAN TODAY IN THE NW...BUT MOST AREAS WILL SEE WARMER
TEMPERATURES.

&&

.LONG TERM...SATURDAY THROUGH WEDNESDAY
ISSUED AT 302 AM MDT THU AUG 28 2014

PROGRESSIVE NORTHERN STREAM FLOW WILL CONTINUE THROUGH THE PERIOD
WITH A LONG WAVE UPPER LEVEL TROUGH ON TRACK TO ADVECT THROUGH THE
REGION SAT-SUN...WITH A WEAKER SHORTWAVE IMPULSE POSSIBLE MONDAY.
TROUGH RELOADING OVER THE NE PAC TUE-WED FAVORED IN ECMWF/GFS
SOLUTIONS...WHICH WOULD SUPPORT MEAN RIDGING OVER THE NORTHERN
PLAINS WITH DRY AND WARMER CONDITIONS. MAIN FORECAST TREND IS A
QUICKER ARRIVAL OF THE EXPECTED LONG WAVE TROUGH SAT...WITH PRECIP
CHANCES INCREASING SAT AFTERNOON WESTERN THIRD. OTHERWISE...THE
REMAINDER OF THE FORECAST IS ON TRACK ATTM.

UPPER LEVEL TROUGH WILL PUSH OUT OF THE NE PAC AND INTO THE NORTHERN
PLAINS...SUPPORTING INCREASING LSA SAT THROUGH SUNDAY. LEE SIDE SFC
TROUGH WILL WILL INTERACT WITH THE APPROACHING UPPER WAVE SUPPORTING
A FOCUS FOR SHRA/TS ACTIVITY OVER THE WESTERN FA BY SAT AFTERNOON.
LL SE FLOW AHEAD OF THIS SYSTEM WITH MOIST UPPER LEVEL SW FLOW WILL
SUPPORT INCREASING PW OVER THE REGION...WITH PLENTY OF MOISTURE
BEING AVAILABLE WITH THIS SYSTEM. SOME MODEL INDICATION FOR
SUFFICIENT DEEP LAYER SHEAR AND CAPE OVER THE FAR NW ZONES...ESP NW
SD BY SAT EVENING...SUPPORTING A POSSIBLE SEVERE THREAT THERE.
SOMETHING TO WATCH. HAVE ADJUSTED POPS UP SAT AFTERNOON AND SAT
EVENING...WITH THE PRIMARY SOUTHERN PERIPHERY IMPULSE EXPECTED TO
SHIFT NE ACROSS THE NW FA. TRAILING SFC TROUGH WITH SUFFICIENT LSA
SHOULD SUPPORT A GOOD CHANCE OF SHRA/TS NW THIRD...WITH MORE
SCT/ISOLD ACTIVITY ACROSS THE REMAINDER OF THE FA. UPPER LEVEL COLD
POOL WILL SUPPORT STEEP LL LAPSE RATES OVER THE FA SUNDAY WITH
RESIDUAL LL MOISTURE IN PLACE. DIURNAL HEATING COUPLED WITH BH/NE WY
TERRAIN INFLUENCES SHOULD SUPPORT SCT TO ISOLD SHRA/TS SW HALF OF
THE FA. BUMPED POPS UP OVER THE BH. OTHERWISE...ONE MORE WEAKER
WESTERLY FLOW IMPULSE STILL INDICATED IN FORECAST MODELS
MONDAY...POSSIBLY SUPPORTING A FEW SHRA/TS...ALTHOUGH UPPER LEVEL
SUPPORT LOOKS MARGINAL ATTM...ESP WITH DRY PROFILES. DRY CONDS
EXPECTED TUE-WED WITH MEAN DEEP LAYER RIDGING.

SEASONAL TEMPS EXPECTED IN MOST OF THE PERIOD...WITH BELOW NORMAL
TEMPS /5-10 DEGREES/ EXPECTED SUNDAY THROUGH MONDAY...ESP NW AREAS.
THE WARMEST DAY IN PERIOD LOOKS TO BE SAT...ESP ON THE SD PLAINS.
ALTHOUGH THERE IS SOME INDICATION FOR WARM CONDITIONS NEXT WED GIVEN
SW WAA FLOW AHEAD OF THE NEXT POTENTIAL EJECTING NE PAC UPPER
TROUGH.

&&

.AVIATION...FOR THE 12Z TAFS THROUGH 12Z FRIDAY
ISSUED AT 302 AM MDT THU AUG 28 2014

WDSPRD SHRA WILL CONTINUE THIS MORNING...MAINLY CNTRL SD. LOCAL
IFR VSBY IN FOG POSSIBLE THERE...ESP INTO NW SD. THE PCPN WILL
SHIFT EAST OF THE REGION THROUGH TODAY. MVFR CIGS EXPECTED TO
REDEVELOP ON THE PLAINS OF WRN SD OVERNIGHT...WITH LCL IFR CONDS
IN FOG. CONDITIONS WILL SLOWLY IMPROVE ON FRIDAY.

&&

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

$$

SHORT TERM...MLS
LONG TERM...JC
AVIATION...JC






000
FXUS65 KRIW 280904
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
304 AM MDT THU AUG 28 2014

.SHORT TERM...TODAY THROUGH SATURDAY NIGHT

LIGHT SHOWERS NOTED ACROSS THE SOUTHEASTERN HALF OF THE FORECAST
AREA THIS MORNING. THE CORE OF THE LOW PRESSURE IS OVER
NORTHEASTERN COLORADO AND IS CONTINUING ON ITS EASTWARD
PROGRESSION. SHOWERS WILL CONTINUE TO TAPER OFF AS THE SYSTEM
MOVES FURTHER EAST...WITH NATRONA AND SWEETWATER COUNTIES LOOKING
TO HOLD ON TO SHOWER ACTIVITY THE LONGEST.

DRY NORTHWEST FLOW BUILDS OVER THE AREA THIS EVENING UNDER THE
INFLUENCE OF A FLATTENED RIDGING PATTERN. THIS SYSTEM WILL ALLOW
SURGES OF MOISTURE TO MOVE INTO THE FORECAST AREA...ESPECIALLY
NORTHWESTERN WYOMING. SHOWERS AND THUNDERSTORMS WILL BE
POSSIBLE...WITH ASSOCIATED THREATS OF GUSTY WIND AND LIGHTNING
ACTIVITY.

ANOTHER TROUGH ADVANCES TOWARDS THE FORECAST AREA BY SATURDAY
MORNING...BRINGING INCREASING SOUTHWEST FLOW OVER THE AREA. GUSTY
WINDS WILL BE POSSIBLE UNDER THIS FLOW...WITH DRIER CONDITIONS NOTED
OVER SOUTHERN WYOMING AHEAD OF THE TROUGH. THIS MAY LEAD TO SOME
ELEVATED FIRE WEATHER CONCERNS...BUT THE SITUATION WILL CONTINUE TO
BE MONITORED.

THE TROUGH WILL STRENGTHEN OVER THE AREA SATURDAY AFTERNOON AND
EVENING...WITH MORE WIDESPREAD SHOWERS AND THUNDERSTORMS
ANTICIPATED. AGAIN...GUSTY WIND AND LIGHTNING WILL BE THE PRIMARY
THREATS WITH STORM ACTIVITY OVER THE NEXT FEW DAYS. THE TROUGH WILL
GENERALLY MOVE THROUGH THE AREA BY SUNDAY MORNING...WITH A RETURN OF
DRY NORTHWEST FLOW.

.LONG TERM...SUNDAY THROUGH WEDNESDAY NIGHT

FAST MOVING FLOW ALOFT DURING MOST OF THE EXTENDED PERIOD WITH A
MID/UPPER LEVEL TROUGH PASSAGE EARLY SUNDAY. MEDIUM RANGE MODELS
GENERALLY HAVE CLOUDS AND MOISTURE EAST OF THE FORECAST AREA BY
SUNDAY AFTERNOON. IN FACT...FAIR WEATHER SHOULD PREVAIL WEST OF
THE DIVIDE ON SUNDAY. THINKING DOWNWARD FORCING BEHIND THIS TROUGH
TO RESULT IN BREEZY TO WINDY CONDITIONS SUNDAY AFTERNOON AND EVENING.

AFTER THIS TIME...FAST ZONAL FLOW OVER WYOMING WITH NEAR NORMAL
TEMPERATURES EXPECTED. MONDAY AND TUESDAY MORNINGS TO START OFF
RELATIVELY COOL. THERE LOOKS TO BE VERY LITTLE SUPPORT ALOFT FOR
PRECIPITATION WITH THIS PATTERN. WILL CALL IT MOSTLY DRY AND
BREEZY THROUGH WEDNESDAY. HOWEVER...CANNOT RULE OUT ISOLATED
SHOWERS OR THUNDERSTORMS EACH DAY ACROSS THE FORECAST AREA.

&&

.AVIATION.../12Z ISSUANCE/

AN UPPER LEVEL LOW PRESSURE SYSTEM WILL CONTINUE TO DRIFT EAST INTO
NE COLORADO EARLY THIS MORNING. PATCHY FOG AND IFR/LIFR CIGS WILL
PARTIALLY OBSCURE TERRAIN VCNTY AND SOUTH OF A KCPR-KRIW-KBPI LINE
UNTIL 14Z.

VFR CONDITIONS WILL THEN PREVAIL ACROSS THE REGION TODAY WITH
SFC-BOUNDARY LAYER WINDS MAINLY OUT OF THE NW AT AROUND 10KTS. A
WEAK UPPER LEVEL DISTURBANCE WILL SPREAD WDLY SCT -SHRA AND ISOLD
-TSRA INTO THE NW MTNS...PRIMARILY NORTH OF A KJAC-KCOD LINE...LATE
THIS AFTERNOON AND EVENING WITH THIS ACTIVITY SPREADING EAST
PRIMARILY VCNTY AND NORTH OF KCOD-KBYG OVERNIGHT WITH CIGS FL120-150.

&&

.FIRE WEATHER...

WEAKENING SHOWERS AND THUNDERSTORMS EXPECTED OVER THE AREA THIS
MORNING...WITH BUILDING DRY WEST TO NORTHWEST FLOW. A FEW SHOWERS
WILL BE POSSIBLE ACROSS THE EXTREME NORTHWEST DURING THE EVENING AND
OVERNIGHT HOURS...WITH DRY CONDITIONS OTHERWISE. AN APPROACHING WAVE
OF LOW PRESSURE WILL TURN THE FLOW TO THE SOUTHWEST LATE FRIDAY AND
INTO SATURDAY. AHEAD OF THE TROUGH AXIS...CONDITIONS ACROSS SOUTHERN
WYOMING COULD BECOME BREEZY AND DRY...RAISING SOME FIRE WEATHER
CONCERNS. THE THREAT WILL BE SHORT LIVED...WITH SHOWERS AND
THUNDERSTORMS ANTICIPATED ACROSS THE AREA BY SATURDAY AFTERNOON.

&&

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

$$

SHORT TERM...BRANHAM
LONG TERM...KPL
AVIATION...KPL
FIRE WEATHER...BRANHAM




000
FXUS65 KRIW 280547 CCA
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
1146 PM MDT WED AUG 27 2014

.SHORT TERM...TONIGHT AND THURSDAY (ISSUED AT 143 PM MDT)

MID LEVEL CIRCULATION NEAR MUDDY GAP AT MIDDAY WITH UPPER
CIRCULATION OVER NERN UT MOVING INTO FAR NWRN CO. IMPRESSIVE VWP
SOUNDING TODAY WITH NE FLOW IN THE MID LEVELS AND SE UPPER FLOW.
BAROCLINIC SHIELD OF PCPN MOVED NWWD ALL THE WAY INTO LND AND THE
EDGE OF RIW WITH .14 INCHES OF RAIN IN LANDER BETWEEN 11 AND NOON
AND ANOTHER .05 BETWEEN NOON AND 1 PM. CAMP CREEK RAWS NEAR MUDDY
GAP REPORTED .83 INCHES OF RAIN THIS MORNING (0.85 NOW). EVEN
SOUTH PASS CITY WAS NEARING THREE QUARTERS OF AN INCH AS OF 1PM.
MANY AREAS OVER NERN SWEETWATER COUNTY...SERN/ERN FREMONT AND
WRN/NRN NATRONA HAVE ALSO LIKELY RECEIVED AROUND A HALF OF AN INCH
THIS MORNING WITH RAIN ONGOING. EVEN RIVERTON IS GETTING
MEASURABLE RAIN WITH 0.03 AS OF 130 PM TODAY. CIRCULATION WILL
WEAKEN AND OPEN UP LATER TODAY AND THEN MOVE OFF TO THE EAST
TONIGHT INTO THURSDAY MORNING. SHOWERS AND ISOLATED THUNDERSTORMS
WILL CONTINUE INTO THE EVENING WITH THE HIGHEST PROBABILITY
SHIFTING SEWD. SHORTWAVE RIDGING THEN MOVES IN FOR A DRY AND WARMER
THURSDAY. BL LOOKS MOIST LATE TONIGHT SO COULD DEFINITELY SEE LOW
CLOUDS AND OR FOG IN OUR SERN ZONES WHERE LIGHT WINDS AND RECENT
RAINFALL HELP OUT.

.LONG TERM...THURSDAY NIGHT THROUGH WEDNESDAY

THE TROUGH THAT IS GIVING SOUTHERN AND EAST CENTRAL WYOMING RAIN
TODAY WILL BE EXITING EAST ACROSS THE PLAINS BY THURSDAY NIGHT. THEN
A FAST MOVING SHORTWAVE WILL BE SCOOTING RAPIDLY EAST ACROSS MONTANA
FRIDAY. THE FLOW OVER WYOMING SOUTH OF THIS SHORTWAVE WILL BE
WESTERLY AND SLIGHTLY DIFLUENT. THE LIFT FROM THIS SHORTWAVE WILL
REMAIN TO THE NORTH IN MONTANA. HIGHER CAPES ARE PROGGED FOR JOHNSON
COUNTY FRIDAY ALONG WITH JUST SLIGHTLY NEGATIVE LIFTED INDICES.
MARGINAL AMOUNTS OF MOISTURE ARE PROGGED FOR FAR NORTHERN WY FRIDAY
WITH MOST OF THE 500-700MB MOISTURE REMAINING UP IN MONTANA. WENT
WITH JUST SCATTERED SHOWERS IN THE NORTHERN MTNS FOR FRIDAY AS WELL
AS IN THE WIND RIVER MOUNTAINS.

THE GFS HAS COME MORE IN LINE WITH THE ECMWF IN THAT IT IS BRINGING
A SHORTWAVE/COLD FRONT THROUGH OUR CWA SATURDAY AND ANOTHER ONE ON MONDAY
ALONG WITH THE ASCT LONG WAVE TROUGH TO PASS THROUGH SUNDAY. HAVE
KEPT WIDESPREAD/NUMEROUS SHOWERS AND A FEW THUNDERSTORMS ACROSS THE
AREA FOP SATURDAY ASCT WITH THE SHORTWAVE...ESP IN THE AFTERNOON AND
IN THE NORTHWEST. ELSEWHERE ON SATURDAY AHEAD OF THE COLD
FRONT...WARM...BREEZY AND DRY CONDITIONS ARE EXPECTED...ESPECIALLY
FROM RKS TO CPR...WHERE FIRE WEATHER CONCERNS WILL LIKELY BE SOMEWHAT
ELEVATED. IN FACT...SATURDAY APPEARS TO BE THE WARMEST DAY OF THE
WEEK WITH HIGHS IN THE 80S EXPECTED AT THE LOWER ELEVATIONS EAST OF
THE DIVIDE AND 70S WEST. H7 TEMPS BEHIND THIS TROUGH/COLD FRONT WILL
DROP TO NEAR ZERO IN NORTHERN WY BY SUNDAY WHICH WOULD BRING THE
SNOW LEVEL DOWN TO 8500 FEET IN THE NORTHERN MTNS. MAINLY SCATTERED
SHOWERS ARE EXPECTED FOR COVERAGE SUNDAY WITH THE LONG WAVE TROUGH.
SCATTERED SHOWER ACTIVITY IS STILL EXPECTED MONDAY WITH THE NEXT
SHORTWAVE. NOT MUCH IN THE WAY OF THUNDERSTORM ACTIVITY ANYWHERE IS
EXPECTED AFTER SATURDAY WITH THE STABILIZING AIR MASS...MAINLY JUST
SHOWERS. WITH A CONTINUED WESTERLY...SOMEWHAT MOIST PACIFIC
FLOW...STILL EXPECTING SOME ISOLATED SHOWERS IN THE HIGHEST FAR NW
MTNS TUESDAY. THIS WESTERLY FLOW WILL RESULT IN JUST DRY CONDITIONS
IN MOST AREAS OF THE CWA TUESDAY. THEN BY WEDNESDAY...THE WEST
SOUTHWEST FLOW WILL INCREASE AHEAD OF AN APPROACHING STRONG CUT OFF
LOW DIVING DOWN SOUTHEAST INTO THE PAC NW WHICH WILL RESULT IN ISOLD
TO WIDELY SCATTERED SHOWERS IN THE NW MTNS AS THE FASTER MORE FALL
LIKE PROGRESSIVE FLOW PATTERN APPEARS TO BECOME ESTABLISHED FOR
NOW.

&&

.AVIATION.../06Z ISSUANCE/

AN UPPER LEVEL LOW PRESSURE SYSTEM WILL CONTINUE TO DRIFT EAST INTO
NE COLORADO EARLY THIS MORNING.  ISOLD TO WDLY SCT -SHRA VCNTY AND
SOUTH OF A KCPR-KRKS LINE WILL DIMINISH THROUGH 9Z.  PATCHY FOG AND
IFR/LIFR CIGS WILL PARTIALLY OBSCURE TERRAIN VCNTY AND SOUTH OF A
KCPR-KRIW-KBPI LINE THROUGH 14Z.

VFR CONDITIONS WILL PREVAIL ACROSS THE REGION ON THURSDAY WITH
SFC-BOUNDARY LAYER WINDS MAINLY OUT OF THE NW AT AROUND 10KTS.
A WEAK UPPER LEVEL DISTURBANCE WILL SPREAD WDLY SCT -SHRA AND ISOLD
-TSRA INTO THE NW MTNS...PRIMARILY NORTH OF A KJAC-KCOD LINE...LATE
THURSDAY AFTERNOON AND EVENING WITH THIS ACTIVITY SPREADING EAST
PRIMARILY VCNTY AND NORTH OF KCOD-KBYG OVERNIGHT WITH CIGS
FL120-150.

&&

.FIRE WEATHER...

AN AREA OF LOW PRESSURE MOVING ALONG THE WYOMING AND COLORADO BORDER
WILL KEEP SHOWERS AND ISOLATED THUNDERSTORMS INTO EARLY THIS EVENING.
MOST SHOWER ACTIVITY WILL IMPACT THE SERN HALF OF THE FORECAST
AREA...THOUGH SOME AREAS OF NORTHERN WYOMING WILL SEE THE
POTENTIAL FOR ISOLATED ACTIVITY THROUGH THE EARLY EVENING HOURS.
THURSDAY WILL BE WARMER AND DRIER BUT WITH NO SIGNIFICANT WINDS. A
WEAK SYSTEM WILL PASS ACROSS THE NORTH ON FRIDAY WITH ISOLATED
SHOWERS AND THUNDERSTORMS AND AREAS OF BREEZY TO LOCALLY WINDY
CONDITIONS.

&&

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

&&

$$

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












000
FXUS65 KRIW 280547 CCA
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
1146 PM MDT WED AUG 27 2014

.SHORT TERM...TONIGHT AND THURSDAY (ISSUED AT 143 PM MDT)

MID LEVEL CIRCULATION NEAR MUDDY GAP AT MIDDAY WITH UPPER
CIRCULATION OVER NERN UT MOVING INTO FAR NWRN CO. IMPRESSIVE VWP
SOUNDING TODAY WITH NE FLOW IN THE MID LEVELS AND SE UPPER FLOW.
BAROCLINIC SHIELD OF PCPN MOVED NWWD ALL THE WAY INTO LND AND THE
EDGE OF RIW WITH .14 INCHES OF RAIN IN LANDER BETWEEN 11 AND NOON
AND ANOTHER .05 BETWEEN NOON AND 1 PM. CAMP CREEK RAWS NEAR MUDDY
GAP REPORTED .83 INCHES OF RAIN THIS MORNING (0.85 NOW). EVEN
SOUTH PASS CITY WAS NEARING THREE QUARTERS OF AN INCH AS OF 1PM.
MANY AREAS OVER NERN SWEETWATER COUNTY...SERN/ERN FREMONT AND
WRN/NRN NATRONA HAVE ALSO LIKELY RECEIVED AROUND A HALF OF AN INCH
THIS MORNING WITH RAIN ONGOING. EVEN RIVERTON IS GETTING
MEASURABLE RAIN WITH 0.03 AS OF 130 PM TODAY. CIRCULATION WILL
WEAKEN AND OPEN UP LATER TODAY AND THEN MOVE OFF TO THE EAST
TONIGHT INTO THURSDAY MORNING. SHOWERS AND ISOLATED THUNDERSTORMS
WILL CONTINUE INTO THE EVENING WITH THE HIGHEST PROBABILITY
SHIFTING SEWD. SHORTWAVE RIDGING THEN MOVES IN FOR A DRY AND WARMER
THURSDAY. BL LOOKS MOIST LATE TONIGHT SO COULD DEFINITELY SEE LOW
CLOUDS AND OR FOG IN OUR SERN ZONES WHERE LIGHT WINDS AND RECENT
RAINFALL HELP OUT.

.LONG TERM...THURSDAY NIGHT THROUGH WEDNESDAY

THE TROUGH THAT IS GIVING SOUTHERN AND EAST CENTRAL WYOMING RAIN
TODAY WILL BE EXITING EAST ACROSS THE PLAINS BY THURSDAY NIGHT. THEN
A FAST MOVING SHORTWAVE WILL BE SCOOTING RAPIDLY EAST ACROSS MONTANA
FRIDAY. THE FLOW OVER WYOMING SOUTH OF THIS SHORTWAVE WILL BE
WESTERLY AND SLIGHTLY DIFLUENT. THE LIFT FROM THIS SHORTWAVE WILL
REMAIN TO THE NORTH IN MONTANA. HIGHER CAPES ARE PROGGED FOR JOHNSON
COUNTY FRIDAY ALONG WITH JUST SLIGHTLY NEGATIVE LIFTED INDICES.
MARGINAL AMOUNTS OF MOISTURE ARE PROGGED FOR FAR NORTHERN WY FRIDAY
WITH MOST OF THE 500-700MB MOISTURE REMAINING UP IN MONTANA. WENT
WITH JUST SCATTERED SHOWERS IN THE NORTHERN MTNS FOR FRIDAY AS WELL
AS IN THE WIND RIVER MOUNTAINS.

THE GFS HAS COME MORE IN LINE WITH THE ECMWF IN THAT IT IS BRINGING
A SHORTWAVE/COLD FRONT THROUGH OUR CWA SATURDAY AND ANOTHER ONE ON MONDAY
ALONG WITH THE ASCT LONG WAVE TROUGH TO PASS THROUGH SUNDAY. HAVE
KEPT WIDESPREAD/NUMEROUS SHOWERS AND A FEW THUNDERSTORMS ACROSS THE
AREA FOP SATURDAY ASCT WITH THE SHORTWAVE...ESP IN THE AFTERNOON AND
IN THE NORTHWEST. ELSEWHERE ON SATURDAY AHEAD OF THE COLD
FRONT...WARM...BREEZY AND DRY CONDITIONS ARE EXPECTED...ESPECIALLY
FROM RKS TO CPR...WHERE FIRE WEATHER CONCERNS WILL LIKELY BE SOMEWHAT
ELEVATED. IN FACT...SATURDAY APPEARS TO BE THE WARMEST DAY OF THE
WEEK WITH HIGHS IN THE 80S EXPECTED AT THE LOWER ELEVATIONS EAST OF
THE DIVIDE AND 70S WEST. H7 TEMPS BEHIND THIS TROUGH/COLD FRONT WILL
DROP TO NEAR ZERO IN NORTHERN WY BY SUNDAY WHICH WOULD BRING THE
SNOW LEVEL DOWN TO 8500 FEET IN THE NORTHERN MTNS. MAINLY SCATTERED
SHOWERS ARE EXPECTED FOR COVERAGE SUNDAY WITH THE LONG WAVE TROUGH.
SCATTERED SHOWER ACTIVITY IS STILL EXPECTED MONDAY WITH THE NEXT
SHORTWAVE. NOT MUCH IN THE WAY OF THUNDERSTORM ACTIVITY ANYWHERE IS
EXPECTED AFTER SATURDAY WITH THE STABILIZING AIR MASS...MAINLY JUST
SHOWERS. WITH A CONTINUED WESTERLY...SOMEWHAT MOIST PACIFIC
FLOW...STILL EXPECTING SOME ISOLATED SHOWERS IN THE HIGHEST FAR NW
MTNS TUESDAY. THIS WESTERLY FLOW WILL RESULT IN JUST DRY CONDITIONS
IN MOST AREAS OF THE CWA TUESDAY. THEN BY WEDNESDAY...THE WEST
SOUTHWEST FLOW WILL INCREASE AHEAD OF AN APPROACHING STRONG CUT OFF
LOW DIVING DOWN SOUTHEAST INTO THE PAC NW WHICH WILL RESULT IN ISOLD
TO WIDELY SCATTERED SHOWERS IN THE NW MTNS AS THE FASTER MORE FALL
LIKE PROGRESSIVE FLOW PATTERN APPEARS TO BECOME ESTABLISHED FOR
NOW.

&&

.AVIATION.../06Z ISSUANCE/

AN UPPER LEVEL LOW PRESSURE SYSTEM WILL CONTINUE TO DRIFT EAST INTO
NE COLORADO EARLY THIS MORNING.  ISOLD TO WDLY SCT -SHRA VCNTY AND
SOUTH OF A KCPR-KRKS LINE WILL DIMINISH THROUGH 9Z.  PATCHY FOG AND
IFR/LIFR CIGS WILL PARTIALLY OBSCURE TERRAIN VCNTY AND SOUTH OF A
KCPR-KRIW-KBPI LINE THROUGH 14Z.

VFR CONDITIONS WILL PREVAIL ACROSS THE REGION ON THURSDAY WITH
SFC-BOUNDARY LAYER WINDS MAINLY OUT OF THE NW AT AROUND 10KTS.
A WEAK UPPER LEVEL DISTURBANCE WILL SPREAD WDLY SCT -SHRA AND ISOLD
-TSRA INTO THE NW MTNS...PRIMARILY NORTH OF A KJAC-KCOD LINE...LATE
THURSDAY AFTERNOON AND EVENING WITH THIS ACTIVITY SPREADING EAST
PRIMARILY VCNTY AND NORTH OF KCOD-KBYG OVERNIGHT WITH CIGS
FL120-150.

&&

.FIRE WEATHER...

AN AREA OF LOW PRESSURE MOVING ALONG THE WYOMING AND COLORADO BORDER
WILL KEEP SHOWERS AND ISOLATED THUNDERSTORMS INTO EARLY THIS EVENING.
MOST SHOWER ACTIVITY WILL IMPACT THE SERN HALF OF THE FORECAST
AREA...THOUGH SOME AREAS OF NORTHERN WYOMING WILL SEE THE
POTENTIAL FOR ISOLATED ACTIVITY THROUGH THE EARLY EVENING HOURS.
THURSDAY WILL BE WARMER AND DRIER BUT WITH NO SIGNIFICANT WINDS. A
WEAK SYSTEM WILL PASS ACROSS THE NORTH ON FRIDAY WITH ISOLATED
SHOWERS AND THUNDERSTORMS AND AREAS OF BREEZY TO LOCALLY WINDY
CONDITIONS.

&&

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

&&

$$

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












000
FXUS65 KRIW 280547 CCA
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
1146 PM MDT WED AUG 27 2014

.SHORT TERM...TONIGHT AND THURSDAY (ISSUED AT 143 PM MDT)

MID LEVEL CIRCULATION NEAR MUDDY GAP AT MIDDAY WITH UPPER
CIRCULATION OVER NERN UT MOVING INTO FAR NWRN CO. IMPRESSIVE VWP
SOUNDING TODAY WITH NE FLOW IN THE MID LEVELS AND SE UPPER FLOW.
BAROCLINIC SHIELD OF PCPN MOVED NWWD ALL THE WAY INTO LND AND THE
EDGE OF RIW WITH .14 INCHES OF RAIN IN LANDER BETWEEN 11 AND NOON
AND ANOTHER .05 BETWEEN NOON AND 1 PM. CAMP CREEK RAWS NEAR MUDDY
GAP REPORTED .83 INCHES OF RAIN THIS MORNING (0.85 NOW). EVEN
SOUTH PASS CITY WAS NEARING THREE QUARTERS OF AN INCH AS OF 1PM.
MANY AREAS OVER NERN SWEETWATER COUNTY...SERN/ERN FREMONT AND
WRN/NRN NATRONA HAVE ALSO LIKELY RECEIVED AROUND A HALF OF AN INCH
THIS MORNING WITH RAIN ONGOING. EVEN RIVERTON IS GETTING
MEASURABLE RAIN WITH 0.03 AS OF 130 PM TODAY. CIRCULATION WILL
WEAKEN AND OPEN UP LATER TODAY AND THEN MOVE OFF TO THE EAST
TONIGHT INTO THURSDAY MORNING. SHOWERS AND ISOLATED THUNDERSTORMS
WILL CONTINUE INTO THE EVENING WITH THE HIGHEST PROBABILITY
SHIFTING SEWD. SHORTWAVE RIDGING THEN MOVES IN FOR A DRY AND WARMER
THURSDAY. BL LOOKS MOIST LATE TONIGHT SO COULD DEFINITELY SEE LOW
CLOUDS AND OR FOG IN OUR SERN ZONES WHERE LIGHT WINDS AND RECENT
RAINFALL HELP OUT.

.LONG TERM...THURSDAY NIGHT THROUGH WEDNESDAY

THE TROUGH THAT IS GIVING SOUTHERN AND EAST CENTRAL WYOMING RAIN
TODAY WILL BE EXITING EAST ACROSS THE PLAINS BY THURSDAY NIGHT. THEN
A FAST MOVING SHORTWAVE WILL BE SCOOTING RAPIDLY EAST ACROSS MONTANA
FRIDAY. THE FLOW OVER WYOMING SOUTH OF THIS SHORTWAVE WILL BE
WESTERLY AND SLIGHTLY DIFLUENT. THE LIFT FROM THIS SHORTWAVE WILL
REMAIN TO THE NORTH IN MONTANA. HIGHER CAPES ARE PROGGED FOR JOHNSON
COUNTY FRIDAY ALONG WITH JUST SLIGHTLY NEGATIVE LIFTED INDICES.
MARGINAL AMOUNTS OF MOISTURE ARE PROGGED FOR FAR NORTHERN WY FRIDAY
WITH MOST OF THE 500-700MB MOISTURE REMAINING UP IN MONTANA. WENT
WITH JUST SCATTERED SHOWERS IN THE NORTHERN MTNS FOR FRIDAY AS WELL
AS IN THE WIND RIVER MOUNTAINS.

THE GFS HAS COME MORE IN LINE WITH THE ECMWF IN THAT IT IS BRINGING
A SHORTWAVE/COLD FRONT THROUGH OUR CWA SATURDAY AND ANOTHER ONE ON MONDAY
ALONG WITH THE ASCT LONG WAVE TROUGH TO PASS THROUGH SUNDAY. HAVE
KEPT WIDESPREAD/NUMEROUS SHOWERS AND A FEW THUNDERSTORMS ACROSS THE
AREA FOP SATURDAY ASCT WITH THE SHORTWAVE...ESP IN THE AFTERNOON AND
IN THE NORTHWEST. ELSEWHERE ON SATURDAY AHEAD OF THE COLD
FRONT...WARM...BREEZY AND DRY CONDITIONS ARE EXPECTED...ESPECIALLY
FROM RKS TO CPR...WHERE FIRE WEATHER CONCERNS WILL LIKELY BE SOMEWHAT
ELEVATED. IN FACT...SATURDAY APPEARS TO BE THE WARMEST DAY OF THE
WEEK WITH HIGHS IN THE 80S EXPECTED AT THE LOWER ELEVATIONS EAST OF
THE DIVIDE AND 70S WEST. H7 TEMPS BEHIND THIS TROUGH/COLD FRONT WILL
DROP TO NEAR ZERO IN NORTHERN WY BY SUNDAY WHICH WOULD BRING THE
SNOW LEVEL DOWN TO 8500 FEET IN THE NORTHERN MTNS. MAINLY SCATTERED
SHOWERS ARE EXPECTED FOR COVERAGE SUNDAY WITH THE LONG WAVE TROUGH.
SCATTERED SHOWER ACTIVITY IS STILL EXPECTED MONDAY WITH THE NEXT
SHORTWAVE. NOT MUCH IN THE WAY OF THUNDERSTORM ACTIVITY ANYWHERE IS
EXPECTED AFTER SATURDAY WITH THE STABILIZING AIR MASS...MAINLY JUST
SHOWERS. WITH A CONTINUED WESTERLY...SOMEWHAT MOIST PACIFIC
FLOW...STILL EXPECTING SOME ISOLATED SHOWERS IN THE HIGHEST FAR NW
MTNS TUESDAY. THIS WESTERLY FLOW WILL RESULT IN JUST DRY CONDITIONS
IN MOST AREAS OF THE CWA TUESDAY. THEN BY WEDNESDAY...THE WEST
SOUTHWEST FLOW WILL INCREASE AHEAD OF AN APPROACHING STRONG CUT OFF
LOW DIVING DOWN SOUTHEAST INTO THE PAC NW WHICH WILL RESULT IN ISOLD
TO WIDELY SCATTERED SHOWERS IN THE NW MTNS AS THE FASTER MORE FALL
LIKE PROGRESSIVE FLOW PATTERN APPEARS TO BECOME ESTABLISHED FOR
NOW.

&&

.AVIATION.../06Z ISSUANCE/

AN UPPER LEVEL LOW PRESSURE SYSTEM WILL CONTINUE TO DRIFT EAST INTO
NE COLORADO EARLY THIS MORNING.  ISOLD TO WDLY SCT -SHRA VCNTY AND
SOUTH OF A KCPR-KRKS LINE WILL DIMINISH THROUGH 9Z.  PATCHY FOG AND
IFR/LIFR CIGS WILL PARTIALLY OBSCURE TERRAIN VCNTY AND SOUTH OF A
KCPR-KRIW-KBPI LINE THROUGH 14Z.

VFR CONDITIONS WILL PREVAIL ACROSS THE REGION ON THURSDAY WITH
SFC-BOUNDARY LAYER WINDS MAINLY OUT OF THE NW AT AROUND 10KTS.
A WEAK UPPER LEVEL DISTURBANCE WILL SPREAD WDLY SCT -SHRA AND ISOLD
-TSRA INTO THE NW MTNS...PRIMARILY NORTH OF A KJAC-KCOD LINE...LATE
THURSDAY AFTERNOON AND EVENING WITH THIS ACTIVITY SPREADING EAST
PRIMARILY VCNTY AND NORTH OF KCOD-KBYG OVERNIGHT WITH CIGS
FL120-150.

&&

.FIRE WEATHER...

AN AREA OF LOW PRESSURE MOVING ALONG THE WYOMING AND COLORADO BORDER
WILL KEEP SHOWERS AND ISOLATED THUNDERSTORMS INTO EARLY THIS EVENING.
MOST SHOWER ACTIVITY WILL IMPACT THE SERN HALF OF THE FORECAST
AREA...THOUGH SOME AREAS OF NORTHERN WYOMING WILL SEE THE
POTENTIAL FOR ISOLATED ACTIVITY THROUGH THE EARLY EVENING HOURS.
THURSDAY WILL BE WARMER AND DRIER BUT WITH NO SIGNIFICANT WINDS. A
WEAK SYSTEM WILL PASS ACROSS THE NORTH ON FRIDAY WITH ISOLATED
SHOWERS AND THUNDERSTORMS AND AREAS OF BREEZY TO LOCALLY WINDY
CONDITIONS.

&&

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

&&

$$

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












000
FXUS65 KRIW 280547 CCA
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
1146 PM MDT WED AUG 27 2014

.SHORT TERM...TONIGHT AND THURSDAY (ISSUED AT 143 PM MDT)

MID LEVEL CIRCULATION NEAR MUDDY GAP AT MIDDAY WITH UPPER
CIRCULATION OVER NERN UT MOVING INTO FAR NWRN CO. IMPRESSIVE VWP
SOUNDING TODAY WITH NE FLOW IN THE MID LEVELS AND SE UPPER FLOW.
BAROCLINIC SHIELD OF PCPN MOVED NWWD ALL THE WAY INTO LND AND THE
EDGE OF RIW WITH .14 INCHES OF RAIN IN LANDER BETWEEN 11 AND NOON
AND ANOTHER .05 BETWEEN NOON AND 1 PM. CAMP CREEK RAWS NEAR MUDDY
GAP REPORTED .83 INCHES OF RAIN THIS MORNING (0.85 NOW). EVEN
SOUTH PASS CITY WAS NEARING THREE QUARTERS OF AN INCH AS OF 1PM.
MANY AREAS OVER NERN SWEETWATER COUNTY...SERN/ERN FREMONT AND
WRN/NRN NATRONA HAVE ALSO LIKELY RECEIVED AROUND A HALF OF AN INCH
THIS MORNING WITH RAIN ONGOING. EVEN RIVERTON IS GETTING
MEASURABLE RAIN WITH 0.03 AS OF 130 PM TODAY. CIRCULATION WILL
WEAKEN AND OPEN UP LATER TODAY AND THEN MOVE OFF TO THE EAST
TONIGHT INTO THURSDAY MORNING. SHOWERS AND ISOLATED THUNDERSTORMS
WILL CONTINUE INTO THE EVENING WITH THE HIGHEST PROBABILITY
SHIFTING SEWD. SHORTWAVE RIDGING THEN MOVES IN FOR A DRY AND WARMER
THURSDAY. BL LOOKS MOIST LATE TONIGHT SO COULD DEFINITELY SEE LOW
CLOUDS AND OR FOG IN OUR SERN ZONES WHERE LIGHT WINDS AND RECENT
RAINFALL HELP OUT.

.LONG TERM...THURSDAY NIGHT THROUGH WEDNESDAY

THE TROUGH THAT IS GIVING SOUTHERN AND EAST CENTRAL WYOMING RAIN
TODAY WILL BE EXITING EAST ACROSS THE PLAINS BY THURSDAY NIGHT. THEN
A FAST MOVING SHORTWAVE WILL BE SCOOTING RAPIDLY EAST ACROSS MONTANA
FRIDAY. THE FLOW OVER WYOMING SOUTH OF THIS SHORTWAVE WILL BE
WESTERLY AND SLIGHTLY DIFLUENT. THE LIFT FROM THIS SHORTWAVE WILL
REMAIN TO THE NORTH IN MONTANA. HIGHER CAPES ARE PROGGED FOR JOHNSON
COUNTY FRIDAY ALONG WITH JUST SLIGHTLY NEGATIVE LIFTED INDICES.
MARGINAL AMOUNTS OF MOISTURE ARE PROGGED FOR FAR NORTHERN WY FRIDAY
WITH MOST OF THE 500-700MB MOISTURE REMAINING UP IN MONTANA. WENT
WITH JUST SCATTERED SHOWERS IN THE NORTHERN MTNS FOR FRIDAY AS WELL
AS IN THE WIND RIVER MOUNTAINS.

THE GFS HAS COME MORE IN LINE WITH THE ECMWF IN THAT IT IS BRINGING
A SHORTWAVE/COLD FRONT THROUGH OUR CWA SATURDAY AND ANOTHER ONE ON MONDAY
ALONG WITH THE ASCT LONG WAVE TROUGH TO PASS THROUGH SUNDAY. HAVE
KEPT WIDESPREAD/NUMEROUS SHOWERS AND A FEW THUNDERSTORMS ACROSS THE
AREA FOP SATURDAY ASCT WITH THE SHORTWAVE...ESP IN THE AFTERNOON AND
IN THE NORTHWEST. ELSEWHERE ON SATURDAY AHEAD OF THE COLD
FRONT...WARM...BREEZY AND DRY CONDITIONS ARE EXPECTED...ESPECIALLY
FROM RKS TO CPR...WHERE FIRE WEATHER CONCERNS WILL LIKELY BE SOMEWHAT
ELEVATED. IN FACT...SATURDAY APPEARS TO BE THE WARMEST DAY OF THE
WEEK WITH HIGHS IN THE 80S EXPECTED AT THE LOWER ELEVATIONS EAST OF
THE DIVIDE AND 70S WEST. H7 TEMPS BEHIND THIS TROUGH/COLD FRONT WILL
DROP TO NEAR ZERO IN NORTHERN WY BY SUNDAY WHICH WOULD BRING THE
SNOW LEVEL DOWN TO 8500 FEET IN THE NORTHERN MTNS. MAINLY SCATTERED
SHOWERS ARE EXPECTED FOR COVERAGE SUNDAY WITH THE LONG WAVE TROUGH.
SCATTERED SHOWER ACTIVITY IS STILL EXPECTED MONDAY WITH THE NEXT
SHORTWAVE. NOT MUCH IN THE WAY OF THUNDERSTORM ACTIVITY ANYWHERE IS
EXPECTED AFTER SATURDAY WITH THE STABILIZING AIR MASS...MAINLY JUST
SHOWERS. WITH A CONTINUED WESTERLY...SOMEWHAT MOIST PACIFIC
FLOW...STILL EXPECTING SOME ISOLATED SHOWERS IN THE HIGHEST FAR NW
MTNS TUESDAY. THIS WESTERLY FLOW WILL RESULT IN JUST DRY CONDITIONS
IN MOST AREAS OF THE CWA TUESDAY. THEN BY WEDNESDAY...THE WEST
SOUTHWEST FLOW WILL INCREASE AHEAD OF AN APPROACHING STRONG CUT OFF
LOW DIVING DOWN SOUTHEAST INTO THE PAC NW WHICH WILL RESULT IN ISOLD
TO WIDELY SCATTERED SHOWERS IN THE NW MTNS AS THE FASTER MORE FALL
LIKE PROGRESSIVE FLOW PATTERN APPEARS TO BECOME ESTABLISHED FOR
NOW.

&&

.AVIATION.../06Z ISSUANCE/

AN UPPER LEVEL LOW PRESSURE SYSTEM WILL CONTINUE TO DRIFT EAST INTO
NE COLORADO EARLY THIS MORNING.  ISOLD TO WDLY SCT -SHRA VCNTY AND
SOUTH OF A KCPR-KRKS LINE WILL DIMINISH THROUGH 9Z.  PATCHY FOG AND
IFR/LIFR CIGS WILL PARTIALLY OBSCURE TERRAIN VCNTY AND SOUTH OF A
KCPR-KRIW-KBPI LINE THROUGH 14Z.

VFR CONDITIONS WILL PREVAIL ACROSS THE REGION ON THURSDAY WITH
SFC-BOUNDARY LAYER WINDS MAINLY OUT OF THE NW AT AROUND 10KTS.
A WEAK UPPER LEVEL DISTURBANCE WILL SPREAD WDLY SCT -SHRA AND ISOLD
-TSRA INTO THE NW MTNS...PRIMARILY NORTH OF A KJAC-KCOD LINE...LATE
THURSDAY AFTERNOON AND EVENING WITH THIS ACTIVITY SPREADING EAST
PRIMARILY VCNTY AND NORTH OF KCOD-KBYG OVERNIGHT WITH CIGS
FL120-150.

&&

.FIRE WEATHER...

AN AREA OF LOW PRESSURE MOVING ALONG THE WYOMING AND COLORADO BORDER
WILL KEEP SHOWERS AND ISOLATED THUNDERSTORMS INTO EARLY THIS EVENING.
MOST SHOWER ACTIVITY WILL IMPACT THE SERN HALF OF THE FORECAST
AREA...THOUGH SOME AREAS OF NORTHERN WYOMING WILL SEE THE
POTENTIAL FOR ISOLATED ACTIVITY THROUGH THE EARLY EVENING HOURS.
THURSDAY WILL BE WARMER AND DRIER BUT WITH NO SIGNIFICANT WINDS. A
WEAK SYSTEM WILL PASS ACROSS THE NORTH ON FRIDAY WITH ISOLATED
SHOWERS AND THUNDERSTORMS AND AREAS OF BREEZY TO LOCALLY WINDY
CONDITIONS.

&&

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

&&

$$

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












000
FXUS63 KUNR 280428
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
1028 PM MDT WED AUG 27 2014

.UPDATE...
ISSUED AT 601 PM MDT WED AUG 27 2014

WDSPRD SHRA/TSRA CONTINUES TO LIFT NEWD ACROSS NERN THROUGH SWRN
SD...SO HAVE RAISED POPS SIGNIFICANTLY FOR THIS EVENING THAT AREA...WHILE
ALSO EXPANDING POPS A BIT FURTHER NORTH. SOME OF THIS RAINFALL IS
VERY HEAVY.

&&

.SHORT TERM...THIS EVENING THROUGH THURSDAY NIGHT
ISSUED AT 305 PM MDT WED AUG 27 2014

CURRENT SURFACE ANALYSIS SHOWS LOW PRESSURE OVER FAR NORTHEAST
CO...WITH A NEARLY STATIONARY FRONTAL BOUNDARY FROM SOUTHERN WY TO
CENTRAL KS. UPPER LEVEL ANALYSIS SHOWS LOW PRESSURE OVER NORTHWEST
CO...WITH TROF COVERING THE ROCKIES AND MUCH OF THE HIGH PLAINS.
SKIES HAVE BECOME MOSTLY CLOUDY ACROSS MUCH OF THE AREA...EXCEPT
FOR FAR NORTHWESTERN SD. REGIONAL RADARS SHOW MAIN BAND OF SHOWERS
AND STORMS ROTATING NORTH-NORTHEAST AROUND UPPER LOW ACROSS MUCH
OF EASTERN WY...THE NEB PANHANDLE...AND INTO FAR SOUTHWESTERN SD.
SCATTERED SHOWERS AND STORMS HAVE DEVELOPED ELSEWHERE ACROSS
SOUTHWEST AND SOUTH CENTRAL SD...AS WELL AS OVER THE BLACK HILLS.
SLOW MOVING STORMS OVER WESTERN PORTIONS OF THE BLACK HILLS HAVE
PRODUCED SOME LOCALLY HEAVY RAINFALL EARLY THIS AFTERNOON.
TEMPERATURES ARE IN THE UPPER 60S AND 70S WITH SOUTHEASTERLY
WINDS.

THE GENERAL TREND FOR SCATTERED TO NUMEROUS SHOWERS AND
THUNDERSTORMS SHOULD CONTINUE INTO TONIGHT ACROSS SOUTHERN PORTIONS
OF THE CWA AS THE UPPER LOW MOVES SLOWLY EAST INTO THE CENTRAL HIGH
PLAINS BY EARLY THURSDAY. THERE WILL BE A FAIRLY SHARP CUT-OFF TO
THE COVERAGE OF SHOWERS THROUGH THE EVENING...GENERALLY SOUTH OF
INTERSTATE 90. THE THREAT FOR SEVERE STORMS REMAINS LOW WITH MAIN
AREA OF INSTABILITY STAYING SOUTH OF THE FORECAST AREA AND WEAK
SHEAR IN PLACE. HOWEVER...THERE IS A THREAT FOR LOCALLY HEAVY
RAINFALL ACROSS SOUTHERN AREAS THIS EVENING...ESPECIALLY OVER FAR
SOUTHWEST INTO SOUTH CENTRAL SD...WHERE PRECIPITABLE WATER VALUES
WILL BE WELL ABOVE AVERAGE AND A COMPLEX OF STORMS COULD MOVE
THROUGH DURING THE EVENING. WITH A LOT OF LOW LEVEL MOISTURE AROUND
THE AREA AND LIGHT WINDS OVERNIGHT...WILL ADD AREAS OF FOG TO MUCH
OF THE WESTERN AND SOUTH CENTRAL SD PLAINS LATE TONIGHT INTO EARLY
THURSDAY.

AS THE UPPER LOW MOVES SLOWLY ACROSS THE CENTRAL HIGH PLAINS LATE
TONIGHT AND THURSDAY...CHANCES FOR SHOWERS AND STORMS SHOULD MOSTLY
BE LIMITED TO THE SOUTH CENTRAL SD AREA. WILL ADD A SLIGHT CHANCE
FOR SHOWERS AND STORMS TO THE CENTRAL AND SOUTHERN BLACK HILLS FOR
THE AFTERNOON WITH SOME LINGERING INSTABILITY AROUND POSSIBLY
PRODUCING A TERRAIN INDUCED SHOWER OR STORM. SKIES WILL BE VARIABLY
CLOUDY...WITH THE MOST SUN ACROSS NORTHERN AND WESTERN PORTIONS OF
THE CWA. WARMER AIR CAN BE EXPECTED ON THURSDAY...ESPECIALLY
ACROSS THESE NORTHERN AND WESTERN AREAS. HIGHS SHOULD RANGE FROM THE
MID 70S TO MID 80S.

CLOUDS WILL CONTINUE TO GRADUALLY DECREASE FROM NORTHWEST TO
SOUTHEAST LATE THURSDAY INTO THURSDAY NIGHT...WITH MOSTLY CLEAR
SKIES OVERNIGHT. SOME FOG COULD AGAIN BE POSSIBLE OVER THE SD PLAINS
LATE...BUT WILL TAKE A CLOSER LOOK AT THAT TOMORROW. LOWS WILL BE IN
THE 50S AND LOWER 60S WITH MOSTLY LIGHT AND VARIABLE WINDS.

&&

.LONG TERM...FRIDAY THROUGH WEDNESDAY
ISSUED AT 305 PM MDT WED AUG 27 2014

FRIDAY...A SHORTWAVE WILL MOVE ACROSS MT/ND PUSHING A COLD FRONT
SOUTH OF THE CWA AS HIGH PRESSURE BUILDS IN OVER SOUTH CENTRAL
CANADA. DEPENDING ON THE AMOUNT OF LOW LEVEL SUBSIDENCE BEHIND THE
SHORTWAVE...A NARROW BAND OF SUFFICIENT CAPE/SHEAR PRESENT FOR
POST FRONTAL ISOLATED STRONG/SEVERE STORMS ACROSS NORTHWEST HALF
OF CWA...BUT CONFIDENCE LOW. TEMPERATURES WILL BE TRICKY WITH WEAK
COOL AIR ADVECTION.

SATURDAY...ANOTHER SHORTWAVE WILL MOVE ACROSS SOUTHERN MT/NORTHERN
WY AHEAD OF LEE TROUGH...WHICH WILL DEVELOP A LOW ALONG IT IN
SOUTHEAST MT AND DRAG ANOTHER COLD FRONT THROUGH THE CWA SATURDAY
NIGHT. SUFFICIENT CAPE/SHEAR WILL BE PRESENT FOR STRONG/SEVERE
STORMS...BUT MLCIN MAY BE NOTABLE GIVEN DEVELOPING THERMAL RIDGE
AHEAD OF SHORTWAVE. TEMPERATURES WILL BE NEAR NORMAL.

HAVE ADDED/EXPANDED POPS BOTH FRIDAY/SATURDAY TO ACCOUNT FOR LATEST
THINKING.

SUNDAY THROUGH WEDNESDAY...ACTIVE PATTERN CONTINUES WITH NORTHWEST
FLOW ALOFT SUNDAY THROUGH TUESDAY...WITH A SLOW TRANSITION TO
RIDGING ACROSS THE NORTHERN PLAINS FOR THE MIDDLE OF THE WEEK.
COOLISH TEMPERATURES TO START SUNDAY BEHIND SATURDAY/S COOL
FRONT...BUT THEN WARMING BACK TO NEAR NORMAL FOR THE MIDDLE OF NEXT
WEEK.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1025 PM MDT WED AUG 27 2014

WDSPRD SHRA WILL CONTINUE TONIGHT...ESPECIALLY EAST OF THE BLKHLS
INTO CNTRL SD. LOCAL IFR VSBY IN HEAVIER -SHRA. THE PCPN WILL THEN
SHIFT EAST OF THE REGION ON THURSDAY. MVFR CIGS EXPECTED TO
REDEVELOP ON THE PLAINS OF WRN SD OVERNIGHT...WITH LCL IFR
CIGS/VSBY IN FOG. CONDITIONS WILL SLOWLY IMPROVE ON THURSDAY.

&&

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

$$

UPDATE...JOHNSON
SHORT TERM...26
LONG TERM...HELGESON
AVIATION...JOHNSON







000
FXUS63 KUNR 280428
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
1028 PM MDT WED AUG 27 2014

.UPDATE...
ISSUED AT 601 PM MDT WED AUG 27 2014

WDSPRD SHRA/TSRA CONTINUES TO LIFT NEWD ACROSS NERN THROUGH SWRN
SD...SO HAVE RAISED POPS SIGNIFICANTLY FOR THIS EVENING THAT AREA...WHILE
ALSO EXPANDING POPS A BIT FURTHER NORTH. SOME OF THIS RAINFALL IS
VERY HEAVY.

&&

.SHORT TERM...THIS EVENING THROUGH THURSDAY NIGHT
ISSUED AT 305 PM MDT WED AUG 27 2014

CURRENT SURFACE ANALYSIS SHOWS LOW PRESSURE OVER FAR NORTHEAST
CO...WITH A NEARLY STATIONARY FRONTAL BOUNDARY FROM SOUTHERN WY TO
CENTRAL KS. UPPER LEVEL ANALYSIS SHOWS LOW PRESSURE OVER NORTHWEST
CO...WITH TROF COVERING THE ROCKIES AND MUCH OF THE HIGH PLAINS.
SKIES HAVE BECOME MOSTLY CLOUDY ACROSS MUCH OF THE AREA...EXCEPT
FOR FAR NORTHWESTERN SD. REGIONAL RADARS SHOW MAIN BAND OF SHOWERS
AND STORMS ROTATING NORTH-NORTHEAST AROUND UPPER LOW ACROSS MUCH
OF EASTERN WY...THE NEB PANHANDLE...AND INTO FAR SOUTHWESTERN SD.
SCATTERED SHOWERS AND STORMS HAVE DEVELOPED ELSEWHERE ACROSS
SOUTHWEST AND SOUTH CENTRAL SD...AS WELL AS OVER THE BLACK HILLS.
SLOW MOVING STORMS OVER WESTERN PORTIONS OF THE BLACK HILLS HAVE
PRODUCED SOME LOCALLY HEAVY RAINFALL EARLY THIS AFTERNOON.
TEMPERATURES ARE IN THE UPPER 60S AND 70S WITH SOUTHEASTERLY
WINDS.

THE GENERAL TREND FOR SCATTERED TO NUMEROUS SHOWERS AND
THUNDERSTORMS SHOULD CONTINUE INTO TONIGHT ACROSS SOUTHERN PORTIONS
OF THE CWA AS THE UPPER LOW MOVES SLOWLY EAST INTO THE CENTRAL HIGH
PLAINS BY EARLY THURSDAY. THERE WILL BE A FAIRLY SHARP CUT-OFF TO
THE COVERAGE OF SHOWERS THROUGH THE EVENING...GENERALLY SOUTH OF
INTERSTATE 90. THE THREAT FOR SEVERE STORMS REMAINS LOW WITH MAIN
AREA OF INSTABILITY STAYING SOUTH OF THE FORECAST AREA AND WEAK
SHEAR IN PLACE. HOWEVER...THERE IS A THREAT FOR LOCALLY HEAVY
RAINFALL ACROSS SOUTHERN AREAS THIS EVENING...ESPECIALLY OVER FAR
SOUTHWEST INTO SOUTH CENTRAL SD...WHERE PRECIPITABLE WATER VALUES
WILL BE WELL ABOVE AVERAGE AND A COMPLEX OF STORMS COULD MOVE
THROUGH DURING THE EVENING. WITH A LOT OF LOW LEVEL MOISTURE AROUND
THE AREA AND LIGHT WINDS OVERNIGHT...WILL ADD AREAS OF FOG TO MUCH
OF THE WESTERN AND SOUTH CENTRAL SD PLAINS LATE TONIGHT INTO EARLY
THURSDAY.

AS THE UPPER LOW MOVES SLOWLY ACROSS THE CENTRAL HIGH PLAINS LATE
TONIGHT AND THURSDAY...CHANCES FOR SHOWERS AND STORMS SHOULD MOSTLY
BE LIMITED TO THE SOUTH CENTRAL SD AREA. WILL ADD A SLIGHT CHANCE
FOR SHOWERS AND STORMS TO THE CENTRAL AND SOUTHERN BLACK HILLS FOR
THE AFTERNOON WITH SOME LINGERING INSTABILITY AROUND POSSIBLY
PRODUCING A TERRAIN INDUCED SHOWER OR STORM. SKIES WILL BE VARIABLY
CLOUDY...WITH THE MOST SUN ACROSS NORTHERN AND WESTERN PORTIONS OF
THE CWA. WARMER AIR CAN BE EXPECTED ON THURSDAY...ESPECIALLY
ACROSS THESE NORTHERN AND WESTERN AREAS. HIGHS SHOULD RANGE FROM THE
MID 70S TO MID 80S.

CLOUDS WILL CONTINUE TO GRADUALLY DECREASE FROM NORTHWEST TO
SOUTHEAST LATE THURSDAY INTO THURSDAY NIGHT...WITH MOSTLY CLEAR
SKIES OVERNIGHT. SOME FOG COULD AGAIN BE POSSIBLE OVER THE SD PLAINS
LATE...BUT WILL TAKE A CLOSER LOOK AT THAT TOMORROW. LOWS WILL BE IN
THE 50S AND LOWER 60S WITH MOSTLY LIGHT AND VARIABLE WINDS.

&&

.LONG TERM...FRIDAY THROUGH WEDNESDAY
ISSUED AT 305 PM MDT WED AUG 27 2014

FRIDAY...A SHORTWAVE WILL MOVE ACROSS MT/ND PUSHING A COLD FRONT
SOUTH OF THE CWA AS HIGH PRESSURE BUILDS IN OVER SOUTH CENTRAL
CANADA. DEPENDING ON THE AMOUNT OF LOW LEVEL SUBSIDENCE BEHIND THE
SHORTWAVE...A NARROW BAND OF SUFFICIENT CAPE/SHEAR PRESENT FOR
POST FRONTAL ISOLATED STRONG/SEVERE STORMS ACROSS NORTHWEST HALF
OF CWA...BUT CONFIDENCE LOW. TEMPERATURES WILL BE TRICKY WITH WEAK
COOL AIR ADVECTION.

SATURDAY...ANOTHER SHORTWAVE WILL MOVE ACROSS SOUTHERN MT/NORTHERN
WY AHEAD OF LEE TROUGH...WHICH WILL DEVELOP A LOW ALONG IT IN
SOUTHEAST MT AND DRAG ANOTHER COLD FRONT THROUGH THE CWA SATURDAY
NIGHT. SUFFICIENT CAPE/SHEAR WILL BE PRESENT FOR STRONG/SEVERE
STORMS...BUT MLCIN MAY BE NOTABLE GIVEN DEVELOPING THERMAL RIDGE
AHEAD OF SHORTWAVE. TEMPERATURES WILL BE NEAR NORMAL.

HAVE ADDED/EXPANDED POPS BOTH FRIDAY/SATURDAY TO ACCOUNT FOR LATEST
THINKING.

SUNDAY THROUGH WEDNESDAY...ACTIVE PATTERN CONTINUES WITH NORTHWEST
FLOW ALOFT SUNDAY THROUGH TUESDAY...WITH A SLOW TRANSITION TO
RIDGING ACROSS THE NORTHERN PLAINS FOR THE MIDDLE OF THE WEEK.
COOLISH TEMPERATURES TO START SUNDAY BEHIND SATURDAY/S COOL
FRONT...BUT THEN WARMING BACK TO NEAR NORMAL FOR THE MIDDLE OF NEXT
WEEK.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1025 PM MDT WED AUG 27 2014

WDSPRD SHRA WILL CONTINUE TONIGHT...ESPECIALLY EAST OF THE BLKHLS
INTO CNTRL SD. LOCAL IFR VSBY IN HEAVIER -SHRA. THE PCPN WILL THEN
SHIFT EAST OF THE REGION ON THURSDAY. MVFR CIGS EXPECTED TO
REDEVELOP ON THE PLAINS OF WRN SD OVERNIGHT...WITH LCL IFR
CIGS/VSBY IN FOG. CONDITIONS WILL SLOWLY IMPROVE ON THURSDAY.

&&

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

$$

UPDATE...JOHNSON
SHORT TERM...26
LONG TERM...HELGESON
AVIATION...JOHNSON







000
FXUS63 KUNR 280428
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
1028 PM MDT WED AUG 27 2014

.UPDATE...
ISSUED AT 601 PM MDT WED AUG 27 2014

WDSPRD SHRA/TSRA CONTINUES TO LIFT NEWD ACROSS NERN THROUGH SWRN
SD...SO HAVE RAISED POPS SIGNIFICANTLY FOR THIS EVENING THAT AREA...WHILE
ALSO EXPANDING POPS A BIT FURTHER NORTH. SOME OF THIS RAINFALL IS
VERY HEAVY.

&&

.SHORT TERM...THIS EVENING THROUGH THURSDAY NIGHT
ISSUED AT 305 PM MDT WED AUG 27 2014

CURRENT SURFACE ANALYSIS SHOWS LOW PRESSURE OVER FAR NORTHEAST
CO...WITH A NEARLY STATIONARY FRONTAL BOUNDARY FROM SOUTHERN WY TO
CENTRAL KS. UPPER LEVEL ANALYSIS SHOWS LOW PRESSURE OVER NORTHWEST
CO...WITH TROF COVERING THE ROCKIES AND MUCH OF THE HIGH PLAINS.
SKIES HAVE BECOME MOSTLY CLOUDY ACROSS MUCH OF THE AREA...EXCEPT
FOR FAR NORTHWESTERN SD. REGIONAL RADARS SHOW MAIN BAND OF SHOWERS
AND STORMS ROTATING NORTH-NORTHEAST AROUND UPPER LOW ACROSS MUCH
OF EASTERN WY...THE NEB PANHANDLE...AND INTO FAR SOUTHWESTERN SD.
SCATTERED SHOWERS AND STORMS HAVE DEVELOPED ELSEWHERE ACROSS
SOUTHWEST AND SOUTH CENTRAL SD...AS WELL AS OVER THE BLACK HILLS.
SLOW MOVING STORMS OVER WESTERN PORTIONS OF THE BLACK HILLS HAVE
PRODUCED SOME LOCALLY HEAVY RAINFALL EARLY THIS AFTERNOON.
TEMPERATURES ARE IN THE UPPER 60S AND 70S WITH SOUTHEASTERLY
WINDS.

THE GENERAL TREND FOR SCATTERED TO NUMEROUS SHOWERS AND
THUNDERSTORMS SHOULD CONTINUE INTO TONIGHT ACROSS SOUTHERN PORTIONS
OF THE CWA AS THE UPPER LOW MOVES SLOWLY EAST INTO THE CENTRAL HIGH
PLAINS BY EARLY THURSDAY. THERE WILL BE A FAIRLY SHARP CUT-OFF TO
THE COVERAGE OF SHOWERS THROUGH THE EVENING...GENERALLY SOUTH OF
INTERSTATE 90. THE THREAT FOR SEVERE STORMS REMAINS LOW WITH MAIN
AREA OF INSTABILITY STAYING SOUTH OF THE FORECAST AREA AND WEAK
SHEAR IN PLACE. HOWEVER...THERE IS A THREAT FOR LOCALLY HEAVY
RAINFALL ACROSS SOUTHERN AREAS THIS EVENING...ESPECIALLY OVER FAR
SOUTHWEST INTO SOUTH CENTRAL SD...WHERE PRECIPITABLE WATER VALUES
WILL BE WELL ABOVE AVERAGE AND A COMPLEX OF STORMS COULD MOVE
THROUGH DURING THE EVENING. WITH A LOT OF LOW LEVEL MOISTURE AROUND
THE AREA AND LIGHT WINDS OVERNIGHT...WILL ADD AREAS OF FOG TO MUCH
OF THE WESTERN AND SOUTH CENTRAL SD PLAINS LATE TONIGHT INTO EARLY
THURSDAY.

AS THE UPPER LOW MOVES SLOWLY ACROSS THE CENTRAL HIGH PLAINS LATE
TONIGHT AND THURSDAY...CHANCES FOR SHOWERS AND STORMS SHOULD MOSTLY
BE LIMITED TO THE SOUTH CENTRAL SD AREA. WILL ADD A SLIGHT CHANCE
FOR SHOWERS AND STORMS TO THE CENTRAL AND SOUTHERN BLACK HILLS FOR
THE AFTERNOON WITH SOME LINGERING INSTABILITY AROUND POSSIBLY
PRODUCING A TERRAIN INDUCED SHOWER OR STORM. SKIES WILL BE VARIABLY
CLOUDY...WITH THE MOST SUN ACROSS NORTHERN AND WESTERN PORTIONS OF
THE CWA. WARMER AIR CAN BE EXPECTED ON THURSDAY...ESPECIALLY
ACROSS THESE NORTHERN AND WESTERN AREAS. HIGHS SHOULD RANGE FROM THE
MID 70S TO MID 80S.

CLOUDS WILL CONTINUE TO GRADUALLY DECREASE FROM NORTHWEST TO
SOUTHEAST LATE THURSDAY INTO THURSDAY NIGHT...WITH MOSTLY CLEAR
SKIES OVERNIGHT. SOME FOG COULD AGAIN BE POSSIBLE OVER THE SD PLAINS
LATE...BUT WILL TAKE A CLOSER LOOK AT THAT TOMORROW. LOWS WILL BE IN
THE 50S AND LOWER 60S WITH MOSTLY LIGHT AND VARIABLE WINDS.

&&

.LONG TERM...FRIDAY THROUGH WEDNESDAY
ISSUED AT 305 PM MDT WED AUG 27 2014

FRIDAY...A SHORTWAVE WILL MOVE ACROSS MT/ND PUSHING A COLD FRONT
SOUTH OF THE CWA AS HIGH PRESSURE BUILDS IN OVER SOUTH CENTRAL
CANADA. DEPENDING ON THE AMOUNT OF LOW LEVEL SUBSIDENCE BEHIND THE
SHORTWAVE...A NARROW BAND OF SUFFICIENT CAPE/SHEAR PRESENT FOR
POST FRONTAL ISOLATED STRONG/SEVERE STORMS ACROSS NORTHWEST HALF
OF CWA...BUT CONFIDENCE LOW. TEMPERATURES WILL BE TRICKY WITH WEAK
COOL AIR ADVECTION.

SATURDAY...ANOTHER SHORTWAVE WILL MOVE ACROSS SOUTHERN MT/NORTHERN
WY AHEAD OF LEE TROUGH...WHICH WILL DEVELOP A LOW ALONG IT IN
SOUTHEAST MT AND DRAG ANOTHER COLD FRONT THROUGH THE CWA SATURDAY
NIGHT. SUFFICIENT CAPE/SHEAR WILL BE PRESENT FOR STRONG/SEVERE
STORMS...BUT MLCIN MAY BE NOTABLE GIVEN DEVELOPING THERMAL RIDGE
AHEAD OF SHORTWAVE. TEMPERATURES WILL BE NEAR NORMAL.

HAVE ADDED/EXPANDED POPS BOTH FRIDAY/SATURDAY TO ACCOUNT FOR LATEST
THINKING.

SUNDAY THROUGH WEDNESDAY...ACTIVE PATTERN CONTINUES WITH NORTHWEST
FLOW ALOFT SUNDAY THROUGH TUESDAY...WITH A SLOW TRANSITION TO
RIDGING ACROSS THE NORTHERN PLAINS FOR THE MIDDLE OF THE WEEK.
COOLISH TEMPERATURES TO START SUNDAY BEHIND SATURDAY/S COOL
FRONT...BUT THEN WARMING BACK TO NEAR NORMAL FOR THE MIDDLE OF NEXT
WEEK.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1025 PM MDT WED AUG 27 2014

WDSPRD SHRA WILL CONTINUE TONIGHT...ESPECIALLY EAST OF THE BLKHLS
INTO CNTRL SD. LOCAL IFR VSBY IN HEAVIER -SHRA. THE PCPN WILL THEN
SHIFT EAST OF THE REGION ON THURSDAY. MVFR CIGS EXPECTED TO
REDEVELOP ON THE PLAINS OF WRN SD OVERNIGHT...WITH LCL IFR
CIGS/VSBY IN FOG. CONDITIONS WILL SLOWLY IMPROVE ON THURSDAY.

&&

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

$$

UPDATE...JOHNSON
SHORT TERM...26
LONG TERM...HELGESON
AVIATION...JOHNSON







000
FXUS63 KUNR 280428
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
1028 PM MDT WED AUG 27 2014

.UPDATE...
ISSUED AT 601 PM MDT WED AUG 27 2014

WDSPRD SHRA/TSRA CONTINUES TO LIFT NEWD ACROSS NERN THROUGH SWRN
SD...SO HAVE RAISED POPS SIGNIFICANTLY FOR THIS EVENING THAT AREA...WHILE
ALSO EXPANDING POPS A BIT FURTHER NORTH. SOME OF THIS RAINFALL IS
VERY HEAVY.

&&

.SHORT TERM...THIS EVENING THROUGH THURSDAY NIGHT
ISSUED AT 305 PM MDT WED AUG 27 2014

CURRENT SURFACE ANALYSIS SHOWS LOW PRESSURE OVER FAR NORTHEAST
CO...WITH A NEARLY STATIONARY FRONTAL BOUNDARY FROM SOUTHERN WY TO
CENTRAL KS. UPPER LEVEL ANALYSIS SHOWS LOW PRESSURE OVER NORTHWEST
CO...WITH TROF COVERING THE ROCKIES AND MUCH OF THE HIGH PLAINS.
SKIES HAVE BECOME MOSTLY CLOUDY ACROSS MUCH OF THE AREA...EXCEPT
FOR FAR NORTHWESTERN SD. REGIONAL RADARS SHOW MAIN BAND OF SHOWERS
AND STORMS ROTATING NORTH-NORTHEAST AROUND UPPER LOW ACROSS MUCH
OF EASTERN WY...THE NEB PANHANDLE...AND INTO FAR SOUTHWESTERN SD.
SCATTERED SHOWERS AND STORMS HAVE DEVELOPED ELSEWHERE ACROSS
SOUTHWEST AND SOUTH CENTRAL SD...AS WELL AS OVER THE BLACK HILLS.
SLOW MOVING STORMS OVER WESTERN PORTIONS OF THE BLACK HILLS HAVE
PRODUCED SOME LOCALLY HEAVY RAINFALL EARLY THIS AFTERNOON.
TEMPERATURES ARE IN THE UPPER 60S AND 70S WITH SOUTHEASTERLY
WINDS.

THE GENERAL TREND FOR SCATTERED TO NUMEROUS SHOWERS AND
THUNDERSTORMS SHOULD CONTINUE INTO TONIGHT ACROSS SOUTHERN PORTIONS
OF THE CWA AS THE UPPER LOW MOVES SLOWLY EAST INTO THE CENTRAL HIGH
PLAINS BY EARLY THURSDAY. THERE WILL BE A FAIRLY SHARP CUT-OFF TO
THE COVERAGE OF SHOWERS THROUGH THE EVENING...GENERALLY SOUTH OF
INTERSTATE 90. THE THREAT FOR SEVERE STORMS REMAINS LOW WITH MAIN
AREA OF INSTABILITY STAYING SOUTH OF THE FORECAST AREA AND WEAK
SHEAR IN PLACE. HOWEVER...THERE IS A THREAT FOR LOCALLY HEAVY
RAINFALL ACROSS SOUTHERN AREAS THIS EVENING...ESPECIALLY OVER FAR
SOUTHWEST INTO SOUTH CENTRAL SD...WHERE PRECIPITABLE WATER VALUES
WILL BE WELL ABOVE AVERAGE AND A COMPLEX OF STORMS COULD MOVE
THROUGH DURING THE EVENING. WITH A LOT OF LOW LEVEL MOISTURE AROUND
THE AREA AND LIGHT WINDS OVERNIGHT...WILL ADD AREAS OF FOG TO MUCH
OF THE WESTERN AND SOUTH CENTRAL SD PLAINS LATE TONIGHT INTO EARLY
THURSDAY.

AS THE UPPER LOW MOVES SLOWLY ACROSS THE CENTRAL HIGH PLAINS LATE
TONIGHT AND THURSDAY...CHANCES FOR SHOWERS AND STORMS SHOULD MOSTLY
BE LIMITED TO THE SOUTH CENTRAL SD AREA. WILL ADD A SLIGHT CHANCE
FOR SHOWERS AND STORMS TO THE CENTRAL AND SOUTHERN BLACK HILLS FOR
THE AFTERNOON WITH SOME LINGERING INSTABILITY AROUND POSSIBLY
PRODUCING A TERRAIN INDUCED SHOWER OR STORM. SKIES WILL BE VARIABLY
CLOUDY...WITH THE MOST SUN ACROSS NORTHERN AND WESTERN PORTIONS OF
THE CWA. WARMER AIR CAN BE EXPECTED ON THURSDAY...ESPECIALLY
ACROSS THESE NORTHERN AND WESTERN AREAS. HIGHS SHOULD RANGE FROM THE
MID 70S TO MID 80S.

CLOUDS WILL CONTINUE TO GRADUALLY DECREASE FROM NORTHWEST TO
SOUTHEAST LATE THURSDAY INTO THURSDAY NIGHT...WITH MOSTLY CLEAR
SKIES OVERNIGHT. SOME FOG COULD AGAIN BE POSSIBLE OVER THE SD PLAINS
LATE...BUT WILL TAKE A CLOSER LOOK AT THAT TOMORROW. LOWS WILL BE IN
THE 50S AND LOWER 60S WITH MOSTLY LIGHT AND VARIABLE WINDS.

&&

.LONG TERM...FRIDAY THROUGH WEDNESDAY
ISSUED AT 305 PM MDT WED AUG 27 2014

FRIDAY...A SHORTWAVE WILL MOVE ACROSS MT/ND PUSHING A COLD FRONT
SOUTH OF THE CWA AS HIGH PRESSURE BUILDS IN OVER SOUTH CENTRAL
CANADA. DEPENDING ON THE AMOUNT OF LOW LEVEL SUBSIDENCE BEHIND THE
SHORTWAVE...A NARROW BAND OF SUFFICIENT CAPE/SHEAR PRESENT FOR
POST FRONTAL ISOLATED STRONG/SEVERE STORMS ACROSS NORTHWEST HALF
OF CWA...BUT CONFIDENCE LOW. TEMPERATURES WILL BE TRICKY WITH WEAK
COOL AIR ADVECTION.

SATURDAY...ANOTHER SHORTWAVE WILL MOVE ACROSS SOUTHERN MT/NORTHERN
WY AHEAD OF LEE TROUGH...WHICH WILL DEVELOP A LOW ALONG IT IN
SOUTHEAST MT AND DRAG ANOTHER COLD FRONT THROUGH THE CWA SATURDAY
NIGHT. SUFFICIENT CAPE/SHEAR WILL BE PRESENT FOR STRONG/SEVERE
STORMS...BUT MLCIN MAY BE NOTABLE GIVEN DEVELOPING THERMAL RIDGE
AHEAD OF SHORTWAVE. TEMPERATURES WILL BE NEAR NORMAL.

HAVE ADDED/EXPANDED POPS BOTH FRIDAY/SATURDAY TO ACCOUNT FOR LATEST
THINKING.

SUNDAY THROUGH WEDNESDAY...ACTIVE PATTERN CONTINUES WITH NORTHWEST
FLOW ALOFT SUNDAY THROUGH TUESDAY...WITH A SLOW TRANSITION TO
RIDGING ACROSS THE NORTHERN PLAINS FOR THE MIDDLE OF THE WEEK.
COOLISH TEMPERATURES TO START SUNDAY BEHIND SATURDAY/S COOL
FRONT...BUT THEN WARMING BACK TO NEAR NORMAL FOR THE MIDDLE OF NEXT
WEEK.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1025 PM MDT WED AUG 27 2014

WDSPRD SHRA WILL CONTINUE TONIGHT...ESPECIALLY EAST OF THE BLKHLS
INTO CNTRL SD. LOCAL IFR VSBY IN HEAVIER -SHRA. THE PCPN WILL THEN
SHIFT EAST OF THE REGION ON THURSDAY. MVFR CIGS EXPECTED TO
REDEVELOP ON THE PLAINS OF WRN SD OVERNIGHT...WITH LCL IFR
CIGS/VSBY IN FOG. CONDITIONS WILL SLOWLY IMPROVE ON THURSDAY.

&&

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

$$

UPDATE...JOHNSON
SHORT TERM...26
LONG TERM...HELGESON
AVIATION...JOHNSON







000
FXUS65 KCYS 280411
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
1011 PM MDT WED AUG 27 2014

.UPDATE...
ISSUED AT 839 PM MDT WED AUG 27 2014

SHORTWAVE TROUGH ALOFT MOVES SLOWLY EASTWARD TO WESTERN NEBRASKA
AND NORTHEAST COLORADO BY DAWN...WITH ENOUGH LOW AND MID LEVEL
MOISTURE FOR ISOLATED TO SCATTERED SHOWERS. AREAS OF FOG LIKELY
OVERNIGHT LOOKING AT PROJECTED TEMPERATURE AND DEWPOINT SPREADS.

&&

.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 413 PM MDT WED AUG 27 2014

THE STRONG UPPER LOW IS MOVING INTO WESTERN COLORADO THIS
AFTERNOON AS SEEN ON WATER VAPOR IMAGERY. A POTENT SHORTWAVE
MOVED OUT AHEAD OF THE LOW AND OVER THE FORECAST AREA THIS
MORNING...SPARKING OFF NUMEROUS SHOWERS AND TSTORMS MAINLY ALONG
AND EAST OF THE LARAMIE RANGE. SOME TRAINING OF STORMS WAS OBSERVED
ALONG A SFC BOUNDARY THAT WAS SITUATED NEAR THE WY/NE BORDER
EARLIER...WITH MODERATE TO HEAVY RAIN OBSERVED WITH THE
THUNDERSTORM ACTIVITY. SOME MINOR TO MODERATE FLOODING OCCURRED
ACROSS CENTRAL GOSHEN COUNTY WITHIN THE AREA OF TRAINING STORMS.
THAT BOUNDARY HAS SINCE PUSHED OFF TO THE SOUTH AND EAST...LIKELY
WITH THE HELP OF THUNDERSTORM OUTFLOW AND AS SFC CYCLOGENESIS IS
OCCURRING IN SOUTHEAST COLORADO...ACCELERATING THE SOUTHWARD
MOVEMENT OF THE BOUNDARY. THE BULK OF THE THUNDERSTORM ACTIVITY IS
NOW OVER FAR NORTHERN AND EASTERN PORTIONS OF THE PANHANDLE THIS
AFTERNOON ON THE LEADING EDGE OF THE SHORTWAVE...WITH THE HEAVIEST
RAIN EXPECTED TO PUSH OFF TO THE EAST-NORTHEAST THROUGH THE
EVENING. ANOTHER ROUND OF SHOWERS AND STORMS ARE MOVING UP FROM
THE SOUTHWEST ON THE NOSE OF A JETLET ROUNDING THE BASE OF THE
TROUGH. THIS ACTIVITY IS OCCURRING WITHIN A DRIER AIRMASS PER
WATER VAPOR IMAGERY...SO RAIN RATES SHOULD BE LESS OVERALL.
INCREASING SOLAR INSOLATION OVER THE NEXT FEW HOURS COULD HELP
DESTABILIZE THE ATMOSPHERE SOMEWHAT ACROSS THE WYO PLAINS...SO
CANNOT RULE OUT THE IDEA THAT THESE STORMS MOVING OFF THE MOUNTAINS
COULD BECOME STRONG WITH THE HELP OF THE APPROACHING JET. HOWEVER THE
ATMOSPHERE IS FAIRLY WORKED OVER FROM EARLIER ACTIVITY SO NOT
WHOLLY CONFIDENT STORMS WILL INTENSIFY MUCH.

THE UPPER LOW WILL CONTINUE TO TREK SOUTHEAST INTO THE CENTRAL
PLAINS THROUGH THURSDAY...WITH WRAPAROUND ENERGY AND MOISTURE
MAINTAINING CHANCES FOR SHOWERS AND TSTORMS ACROSS THE CWA TONIGHT.
MIDLEVEL CONVERGENCE WITHIN THE TROUGH AXIS WILL MOVE OVERHEAD ON
THURSDAY...WITH THE ADDITION OF BROADSCALE LIFT WITHIN THE LEFT
ENTRANCE OF THE CURVED JET AIDING IN DEVELOPMENT OF CONVECTION
THROUGH THE DAY. THE MAIN FOCUS WILL BE SOUTH OF A RAWLINS-LUSK-
CHADRON LINE. MUCH DRIER AIR WILL FILTER IN FROM THE NORTHWEST AS
A SHORTWAVE RIDGE MOVES OVERHEAD THURSDAY NIGHT AND EARLY
FRIDAY...WITH A WEAK WAVE APPROACHING FROM THE NORTHWEST FRIDAY
AFTERNOON. A FEW WEAK TSTORMS ARE POSSIBLE IN THE AFTERNOON AS THE
WAVE APPROACHES.

.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 413 PM MDT WED AUG 27 2014

MEDIUM RANGE MODELS ARE IN EXCELLENT AGREEMENT WITH A BROAD MIDLVL
SHORTWAVE MOVING ACROSS THE PACIFIC NW EARLY IN THE PERIOD. SEASONAL
WARMTH WILL OCCUR IN ADVANCE OF THIS FEATURE WITH H7 TEMPS AROUND 10
TO 14 C PER THE GFS ON SAT. CONSIDERABLE 700-300 MILLIBAR MOISTURE
AND INCREASING QG ASCENT WITH THE APPROACHING WAVE WOULD SUGGEST AN
INCREASE IN SHOWER AND TSTM ACTIVITY...EVEN AT NON DIURNALLY FAVORED
TIMES OF DAY. DO NOT EXPECT A WASHOUT BY ANY MEANS...BUT THERE WILL
PROBABLY BE CONVECTION AROUND. LOOKING A BIT BREEZY EACH AFTN OVER
THE HOLIDAY WEEKEND...ESPECIALLY WEST OF THE LARAMIE RANGE WITH AN
INCREASE IN HEIGHT GRADIENTS ALOFT AND THE SFC LOW PASSING ACROSS
NORTHERN WY. COOLER ON SUN/MON AS THE UPPER-LEVEL SYSTEM MOVES
OVERHEAD. THE ECMWF SHOWS 1000-500 MILLIBAR THICKNESSES FALLING TO
AROUND 570 DM...AND MOS GUIDANCE SUGGESTS SFC TEMPS WILL BE A GOOD
10 TO 15 DEGREES COOLER WHEN COMPARED TO SAT. AN UNSETTLED WEATHER
PATTERN WILL PERSIST THRU EARLY NEXT WEEK WITH DISTURBANCES EMBEDDED
WITHIN QUASI-ZONAL FLOW. WEAK UPPER-LEVEL RIDGING SHOULD GIVE WAY TO
A GRADUAL WARMING TREND THROUGH MIDWEEK WITH LESSER CHANCES FOR PCPN
FROM TUE ONWARD.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY EVENING)
ISSUED AT 1008 PM MDT WED AUG 27 2014

ISOLATED TO SCATTERED SHOWERS THE REST OF THE NIGHT. AREAS OF LOW
CLOUDS AND FOG DEVELOPING OVERNIGHT PRODUCING IFR...OTHERWISE VFR
PREVAILS. FOG AND LOW CLOUDS LIFTING BY MID MORNING THURSDAY.
VFR PREVAILS ON THURSDAY WITH LOCALIZED MVFR IN ISOLATED TO
SCATTERED SHOWERS AND THUNDERSTORMS THURSDAY AFTERNOON SOUTH OF A
RAWLINS TO SCOTTSBLUFF LINE.

&&

.FIRE WEATHER...
ISSUED AT 413 PM MDT WED AUG 27 2014

NUMEROUS SHOWERS AND SCATTERED THUNDERSTORMS WILL
CONTINUE OVER THE DISTRICT THIS AFTERNOON AND TONIGHT. THIS
ACTIVITY WILL PRODUCE MODERATE TO HEAVY RAIN AND PERHAPS SOME
SMALL HAIL AS WELL. A MORE ISOLATED COVERAGE FOR SHOWERS AND
T-STORMS IS EXPECTED FOR THURSDAY...WITH THE MAIN FOCUS FOR THIS
ACTIVITY IN THE MOUNTAINS AND NEAR THE COLORADO BORDER. DRIER AND
WARMER WEATHER WILL RETURN FRIDAY AND CONTINUE THIS
WEEKEND...ALONG WITH GUSTY WEST TO SOUTHWEST WINDS. THERE WILL BE
A SLIGHT CHANCE FOR SHOWERS AND THUNDERSTORMS LATE SUNDAY AND LABOR
DAY WITH THE PASSAGE OF A UPPER LEVEL TROUGH AND PACIFIC COLD
FRONT.

&&

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

$$

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







000
FXUS65 KCYS 280411
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
1011 PM MDT WED AUG 27 2014

.UPDATE...
ISSUED AT 839 PM MDT WED AUG 27 2014

SHORTWAVE TROUGH ALOFT MOVES SLOWLY EASTWARD TO WESTERN NEBRASKA
AND NORTHEAST COLORADO BY DAWN...WITH ENOUGH LOW AND MID LEVEL
MOISTURE FOR ISOLATED TO SCATTERED SHOWERS. AREAS OF FOG LIKELY
OVERNIGHT LOOKING AT PROJECTED TEMPERATURE AND DEWPOINT SPREADS.

&&

.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 413 PM MDT WED AUG 27 2014

THE STRONG UPPER LOW IS MOVING INTO WESTERN COLORADO THIS
AFTERNOON AS SEEN ON WATER VAPOR IMAGERY. A POTENT SHORTWAVE
MOVED OUT AHEAD OF THE LOW AND OVER THE FORECAST AREA THIS
MORNING...SPARKING OFF NUMEROUS SHOWERS AND TSTORMS MAINLY ALONG
AND EAST OF THE LARAMIE RANGE. SOME TRAINING OF STORMS WAS OBSERVED
ALONG A SFC BOUNDARY THAT WAS SITUATED NEAR THE WY/NE BORDER
EARLIER...WITH MODERATE TO HEAVY RAIN OBSERVED WITH THE
THUNDERSTORM ACTIVITY. SOME MINOR TO MODERATE FLOODING OCCURRED
ACROSS CENTRAL GOSHEN COUNTY WITHIN THE AREA OF TRAINING STORMS.
THAT BOUNDARY HAS SINCE PUSHED OFF TO THE SOUTH AND EAST...LIKELY
WITH THE HELP OF THUNDERSTORM OUTFLOW AND AS SFC CYCLOGENESIS IS
OCCURRING IN SOUTHEAST COLORADO...ACCELERATING THE SOUTHWARD
MOVEMENT OF THE BOUNDARY. THE BULK OF THE THUNDERSTORM ACTIVITY IS
NOW OVER FAR NORTHERN AND EASTERN PORTIONS OF THE PANHANDLE THIS
AFTERNOON ON THE LEADING EDGE OF THE SHORTWAVE...WITH THE HEAVIEST
RAIN EXPECTED TO PUSH OFF TO THE EAST-NORTHEAST THROUGH THE
EVENING. ANOTHER ROUND OF SHOWERS AND STORMS ARE MOVING UP FROM
THE SOUTHWEST ON THE NOSE OF A JETLET ROUNDING THE BASE OF THE
TROUGH. THIS ACTIVITY IS OCCURRING WITHIN A DRIER AIRMASS PER
WATER VAPOR IMAGERY...SO RAIN RATES SHOULD BE LESS OVERALL.
INCREASING SOLAR INSOLATION OVER THE NEXT FEW HOURS COULD HELP
DESTABILIZE THE ATMOSPHERE SOMEWHAT ACROSS THE WYO PLAINS...SO
CANNOT RULE OUT THE IDEA THAT THESE STORMS MOVING OFF THE MOUNTAINS
COULD BECOME STRONG WITH THE HELP OF THE APPROACHING JET. HOWEVER THE
ATMOSPHERE IS FAIRLY WORKED OVER FROM EARLIER ACTIVITY SO NOT
WHOLLY CONFIDENT STORMS WILL INTENSIFY MUCH.

THE UPPER LOW WILL CONTINUE TO TREK SOUTHEAST INTO THE CENTRAL
PLAINS THROUGH THURSDAY...WITH WRAPAROUND ENERGY AND MOISTURE
MAINTAINING CHANCES FOR SHOWERS AND TSTORMS ACROSS THE CWA TONIGHT.
MIDLEVEL CONVERGENCE WITHIN THE TROUGH AXIS WILL MOVE OVERHEAD ON
THURSDAY...WITH THE ADDITION OF BROADSCALE LIFT WITHIN THE LEFT
ENTRANCE OF THE CURVED JET AIDING IN DEVELOPMENT OF CONVECTION
THROUGH THE DAY. THE MAIN FOCUS WILL BE SOUTH OF A RAWLINS-LUSK-
CHADRON LINE. MUCH DRIER AIR WILL FILTER IN FROM THE NORTHWEST AS
A SHORTWAVE RIDGE MOVES OVERHEAD THURSDAY NIGHT AND EARLY
FRIDAY...WITH A WEAK WAVE APPROACHING FROM THE NORTHWEST FRIDAY
AFTERNOON. A FEW WEAK TSTORMS ARE POSSIBLE IN THE AFTERNOON AS THE
WAVE APPROACHES.

.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 413 PM MDT WED AUG 27 2014

MEDIUM RANGE MODELS ARE IN EXCELLENT AGREEMENT WITH A BROAD MIDLVL
SHORTWAVE MOVING ACROSS THE PACIFIC NW EARLY IN THE PERIOD. SEASONAL
WARMTH WILL OCCUR IN ADVANCE OF THIS FEATURE WITH H7 TEMPS AROUND 10
TO 14 C PER THE GFS ON SAT. CONSIDERABLE 700-300 MILLIBAR MOISTURE
AND INCREASING QG ASCENT WITH THE APPROACHING WAVE WOULD SUGGEST AN
INCREASE IN SHOWER AND TSTM ACTIVITY...EVEN AT NON DIURNALLY FAVORED
TIMES OF DAY. DO NOT EXPECT A WASHOUT BY ANY MEANS...BUT THERE WILL
PROBABLY BE CONVECTION AROUND. LOOKING A BIT BREEZY EACH AFTN OVER
THE HOLIDAY WEEKEND...ESPECIALLY WEST OF THE LARAMIE RANGE WITH AN
INCREASE IN HEIGHT GRADIENTS ALOFT AND THE SFC LOW PASSING ACROSS
NORTHERN WY. COOLER ON SUN/MON AS THE UPPER-LEVEL SYSTEM MOVES
OVERHEAD. THE ECMWF SHOWS 1000-500 MILLIBAR THICKNESSES FALLING TO
AROUND 570 DM...AND MOS GUIDANCE SUGGESTS SFC TEMPS WILL BE A GOOD
10 TO 15 DEGREES COOLER WHEN COMPARED TO SAT. AN UNSETTLED WEATHER
PATTERN WILL PERSIST THRU EARLY NEXT WEEK WITH DISTURBANCES EMBEDDED
WITHIN QUASI-ZONAL FLOW. WEAK UPPER-LEVEL RIDGING SHOULD GIVE WAY TO
A GRADUAL WARMING TREND THROUGH MIDWEEK WITH LESSER CHANCES FOR PCPN
FROM TUE ONWARD.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY EVENING)
ISSUED AT 1008 PM MDT WED AUG 27 2014

ISOLATED TO SCATTERED SHOWERS THE REST OF THE NIGHT. AREAS OF LOW
CLOUDS AND FOG DEVELOPING OVERNIGHT PRODUCING IFR...OTHERWISE VFR
PREVAILS. FOG AND LOW CLOUDS LIFTING BY MID MORNING THURSDAY.
VFR PREVAILS ON THURSDAY WITH LOCALIZED MVFR IN ISOLATED TO
SCATTERED SHOWERS AND THUNDERSTORMS THURSDAY AFTERNOON SOUTH OF A
RAWLINS TO SCOTTSBLUFF LINE.

&&

.FIRE WEATHER...
ISSUED AT 413 PM MDT WED AUG 27 2014

NUMEROUS SHOWERS AND SCATTERED THUNDERSTORMS WILL
CONTINUE OVER THE DISTRICT THIS AFTERNOON AND TONIGHT. THIS
ACTIVITY WILL PRODUCE MODERATE TO HEAVY RAIN AND PERHAPS SOME
SMALL HAIL AS WELL. A MORE ISOLATED COVERAGE FOR SHOWERS AND
T-STORMS IS EXPECTED FOR THURSDAY...WITH THE MAIN FOCUS FOR THIS
ACTIVITY IN THE MOUNTAINS AND NEAR THE COLORADO BORDER. DRIER AND
WARMER WEATHER WILL RETURN FRIDAY AND CONTINUE THIS
WEEKEND...ALONG WITH GUSTY WEST TO SOUTHWEST WINDS. THERE WILL BE
A SLIGHT CHANCE FOR SHOWERS AND THUNDERSTORMS LATE SUNDAY AND LABOR
DAY WITH THE PASSAGE OF A UPPER LEVEL TROUGH AND PACIFIC COLD
FRONT.

&&

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

$$

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







000
FXUS65 KCYS 280411
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
1011 PM MDT WED AUG 27 2014

.UPDATE...
ISSUED AT 839 PM MDT WED AUG 27 2014

SHORTWAVE TROUGH ALOFT MOVES SLOWLY EASTWARD TO WESTERN NEBRASKA
AND NORTHEAST COLORADO BY DAWN...WITH ENOUGH LOW AND MID LEVEL
MOISTURE FOR ISOLATED TO SCATTERED SHOWERS. AREAS OF FOG LIKELY
OVERNIGHT LOOKING AT PROJECTED TEMPERATURE AND DEWPOINT SPREADS.

&&

.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 413 PM MDT WED AUG 27 2014

THE STRONG UPPER LOW IS MOVING INTO WESTERN COLORADO THIS
AFTERNOON AS SEEN ON WATER VAPOR IMAGERY. A POTENT SHORTWAVE
MOVED OUT AHEAD OF THE LOW AND OVER THE FORECAST AREA THIS
MORNING...SPARKING OFF NUMEROUS SHOWERS AND TSTORMS MAINLY ALONG
AND EAST OF THE LARAMIE RANGE. SOME TRAINING OF STORMS WAS OBSERVED
ALONG A SFC BOUNDARY THAT WAS SITUATED NEAR THE WY/NE BORDER
EARLIER...WITH MODERATE TO HEAVY RAIN OBSERVED WITH THE
THUNDERSTORM ACTIVITY. SOME MINOR TO MODERATE FLOODING OCCURRED
ACROSS CENTRAL GOSHEN COUNTY WITHIN THE AREA OF TRAINING STORMS.
THAT BOUNDARY HAS SINCE PUSHED OFF TO THE SOUTH AND EAST...LIKELY
WITH THE HELP OF THUNDERSTORM OUTFLOW AND AS SFC CYCLOGENESIS IS
OCCURRING IN SOUTHEAST COLORADO...ACCELERATING THE SOUTHWARD
MOVEMENT OF THE BOUNDARY. THE BULK OF THE THUNDERSTORM ACTIVITY IS
NOW OVER FAR NORTHERN AND EASTERN PORTIONS OF THE PANHANDLE THIS
AFTERNOON ON THE LEADING EDGE OF THE SHORTWAVE...WITH THE HEAVIEST
RAIN EXPECTED TO PUSH OFF TO THE EAST-NORTHEAST THROUGH THE
EVENING. ANOTHER ROUND OF SHOWERS AND STORMS ARE MOVING UP FROM
THE SOUTHWEST ON THE NOSE OF A JETLET ROUNDING THE BASE OF THE
TROUGH. THIS ACTIVITY IS OCCURRING WITHIN A DRIER AIRMASS PER
WATER VAPOR IMAGERY...SO RAIN RATES SHOULD BE LESS OVERALL.
INCREASING SOLAR INSOLATION OVER THE NEXT FEW HOURS COULD HELP
DESTABILIZE THE ATMOSPHERE SOMEWHAT ACROSS THE WYO PLAINS...SO
CANNOT RULE OUT THE IDEA THAT THESE STORMS MOVING OFF THE MOUNTAINS
COULD BECOME STRONG WITH THE HELP OF THE APPROACHING JET. HOWEVER THE
ATMOSPHERE IS FAIRLY WORKED OVER FROM EARLIER ACTIVITY SO NOT
WHOLLY CONFIDENT STORMS WILL INTENSIFY MUCH.

THE UPPER LOW WILL CONTINUE TO TREK SOUTHEAST INTO THE CENTRAL
PLAINS THROUGH THURSDAY...WITH WRAPAROUND ENERGY AND MOISTURE
MAINTAINING CHANCES FOR SHOWERS AND TSTORMS ACROSS THE CWA TONIGHT.
MIDLEVEL CONVERGENCE WITHIN THE TROUGH AXIS WILL MOVE OVERHEAD ON
THURSDAY...WITH THE ADDITION OF BROADSCALE LIFT WITHIN THE LEFT
ENTRANCE OF THE CURVED JET AIDING IN DEVELOPMENT OF CONVECTION
THROUGH THE DAY. THE MAIN FOCUS WILL BE SOUTH OF A RAWLINS-LUSK-
CHADRON LINE. MUCH DRIER AIR WILL FILTER IN FROM THE NORTHWEST AS
A SHORTWAVE RIDGE MOVES OVERHEAD THURSDAY NIGHT AND EARLY
FRIDAY...WITH A WEAK WAVE APPROACHING FROM THE NORTHWEST FRIDAY
AFTERNOON. A FEW WEAK TSTORMS ARE POSSIBLE IN THE AFTERNOON AS THE
WAVE APPROACHES.

.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 413 PM MDT WED AUG 27 2014

MEDIUM RANGE MODELS ARE IN EXCELLENT AGREEMENT WITH A BROAD MIDLVL
SHORTWAVE MOVING ACROSS THE PACIFIC NW EARLY IN THE PERIOD. SEASONAL
WARMTH WILL OCCUR IN ADVANCE OF THIS FEATURE WITH H7 TEMPS AROUND 10
TO 14 C PER THE GFS ON SAT. CONSIDERABLE 700-300 MILLIBAR MOISTURE
AND INCREASING QG ASCENT WITH THE APPROACHING WAVE WOULD SUGGEST AN
INCREASE IN SHOWER AND TSTM ACTIVITY...EVEN AT NON DIURNALLY FAVORED
TIMES OF DAY. DO NOT EXPECT A WASHOUT BY ANY MEANS...BUT THERE WILL
PROBABLY BE CONVECTION AROUND. LOOKING A BIT BREEZY EACH AFTN OVER
THE HOLIDAY WEEKEND...ESPECIALLY WEST OF THE LARAMIE RANGE WITH AN
INCREASE IN HEIGHT GRADIENTS ALOFT AND THE SFC LOW PASSING ACROSS
NORTHERN WY. COOLER ON SUN/MON AS THE UPPER-LEVEL SYSTEM MOVES
OVERHEAD. THE ECMWF SHOWS 1000-500 MILLIBAR THICKNESSES FALLING TO
AROUND 570 DM...AND MOS GUIDANCE SUGGESTS SFC TEMPS WILL BE A GOOD
10 TO 15 DEGREES COOLER WHEN COMPARED TO SAT. AN UNSETTLED WEATHER
PATTERN WILL PERSIST THRU EARLY NEXT WEEK WITH DISTURBANCES EMBEDDED
WITHIN QUASI-ZONAL FLOW. WEAK UPPER-LEVEL RIDGING SHOULD GIVE WAY TO
A GRADUAL WARMING TREND THROUGH MIDWEEK WITH LESSER CHANCES FOR PCPN
FROM TUE ONWARD.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY EVENING)
ISSUED AT 1008 PM MDT WED AUG 27 2014

ISOLATED TO SCATTERED SHOWERS THE REST OF THE NIGHT. AREAS OF LOW
CLOUDS AND FOG DEVELOPING OVERNIGHT PRODUCING IFR...OTHERWISE VFR
PREVAILS. FOG AND LOW CLOUDS LIFTING BY MID MORNING THURSDAY.
VFR PREVAILS ON THURSDAY WITH LOCALIZED MVFR IN ISOLATED TO
SCATTERED SHOWERS AND THUNDERSTORMS THURSDAY AFTERNOON SOUTH OF A
RAWLINS TO SCOTTSBLUFF LINE.

&&

.FIRE WEATHER...
ISSUED AT 413 PM MDT WED AUG 27 2014

NUMEROUS SHOWERS AND SCATTERED THUNDERSTORMS WILL
CONTINUE OVER THE DISTRICT THIS AFTERNOON AND TONIGHT. THIS
ACTIVITY WILL PRODUCE MODERATE TO HEAVY RAIN AND PERHAPS SOME
SMALL HAIL AS WELL. A MORE ISOLATED COVERAGE FOR SHOWERS AND
T-STORMS IS EXPECTED FOR THURSDAY...WITH THE MAIN FOCUS FOR THIS
ACTIVITY IN THE MOUNTAINS AND NEAR THE COLORADO BORDER. DRIER AND
WARMER WEATHER WILL RETURN FRIDAY AND CONTINUE THIS
WEEKEND...ALONG WITH GUSTY WEST TO SOUTHWEST WINDS. THERE WILL BE
A SLIGHT CHANCE FOR SHOWERS AND THUNDERSTORMS LATE SUNDAY AND LABOR
DAY WITH THE PASSAGE OF A UPPER LEVEL TROUGH AND PACIFIC COLD
FRONT.

&&

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

$$

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







000
FXUS65 KCYS 280411
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
1011 PM MDT WED AUG 27 2014

.UPDATE...
ISSUED AT 839 PM MDT WED AUG 27 2014

SHORTWAVE TROUGH ALOFT MOVES SLOWLY EASTWARD TO WESTERN NEBRASKA
AND NORTHEAST COLORADO BY DAWN...WITH ENOUGH LOW AND MID LEVEL
MOISTURE FOR ISOLATED TO SCATTERED SHOWERS. AREAS OF FOG LIKELY
OVERNIGHT LOOKING AT PROJECTED TEMPERATURE AND DEWPOINT SPREADS.

&&

.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 413 PM MDT WED AUG 27 2014

THE STRONG UPPER LOW IS MOVING INTO WESTERN COLORADO THIS
AFTERNOON AS SEEN ON WATER VAPOR IMAGERY. A POTENT SHORTWAVE
MOVED OUT AHEAD OF THE LOW AND OVER THE FORECAST AREA THIS
MORNING...SPARKING OFF NUMEROUS SHOWERS AND TSTORMS MAINLY ALONG
AND EAST OF THE LARAMIE RANGE. SOME TRAINING OF STORMS WAS OBSERVED
ALONG A SFC BOUNDARY THAT WAS SITUATED NEAR THE WY/NE BORDER
EARLIER...WITH MODERATE TO HEAVY RAIN OBSERVED WITH THE
THUNDERSTORM ACTIVITY. SOME MINOR TO MODERATE FLOODING OCCURRED
ACROSS CENTRAL GOSHEN COUNTY WITHIN THE AREA OF TRAINING STORMS.
THAT BOUNDARY HAS SINCE PUSHED OFF TO THE SOUTH AND EAST...LIKELY
WITH THE HELP OF THUNDERSTORM OUTFLOW AND AS SFC CYCLOGENESIS IS
OCCURRING IN SOUTHEAST COLORADO...ACCELERATING THE SOUTHWARD
MOVEMENT OF THE BOUNDARY. THE BULK OF THE THUNDERSTORM ACTIVITY IS
NOW OVER FAR NORTHERN AND EASTERN PORTIONS OF THE PANHANDLE THIS
AFTERNOON ON THE LEADING EDGE OF THE SHORTWAVE...WITH THE HEAVIEST
RAIN EXPECTED TO PUSH OFF TO THE EAST-NORTHEAST THROUGH THE
EVENING. ANOTHER ROUND OF SHOWERS AND STORMS ARE MOVING UP FROM
THE SOUTHWEST ON THE NOSE OF A JETLET ROUNDING THE BASE OF THE
TROUGH. THIS ACTIVITY IS OCCURRING WITHIN A DRIER AIRMASS PER
WATER VAPOR IMAGERY...SO RAIN RATES SHOULD BE LESS OVERALL.
INCREASING SOLAR INSOLATION OVER THE NEXT FEW HOURS COULD HELP
DESTABILIZE THE ATMOSPHERE SOMEWHAT ACROSS THE WYO PLAINS...SO
CANNOT RULE OUT THE IDEA THAT THESE STORMS MOVING OFF THE MOUNTAINS
COULD BECOME STRONG WITH THE HELP OF THE APPROACHING JET. HOWEVER THE
ATMOSPHERE IS FAIRLY WORKED OVER FROM EARLIER ACTIVITY SO NOT
WHOLLY CONFIDENT STORMS WILL INTENSIFY MUCH.

THE UPPER LOW WILL CONTINUE TO TREK SOUTHEAST INTO THE CENTRAL
PLAINS THROUGH THURSDAY...WITH WRAPAROUND ENERGY AND MOISTURE
MAINTAINING CHANCES FOR SHOWERS AND TSTORMS ACROSS THE CWA TONIGHT.
MIDLEVEL CONVERGENCE WITHIN THE TROUGH AXIS WILL MOVE OVERHEAD ON
THURSDAY...WITH THE ADDITION OF BROADSCALE LIFT WITHIN THE LEFT
ENTRANCE OF THE CURVED JET AIDING IN DEVELOPMENT OF CONVECTION
THROUGH THE DAY. THE MAIN FOCUS WILL BE SOUTH OF A RAWLINS-LUSK-
CHADRON LINE. MUCH DRIER AIR WILL FILTER IN FROM THE NORTHWEST AS
A SHORTWAVE RIDGE MOVES OVERHEAD THURSDAY NIGHT AND EARLY
FRIDAY...WITH A WEAK WAVE APPROACHING FROM THE NORTHWEST FRIDAY
AFTERNOON. A FEW WEAK TSTORMS ARE POSSIBLE IN THE AFTERNOON AS THE
WAVE APPROACHES.

.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 413 PM MDT WED AUG 27 2014

MEDIUM RANGE MODELS ARE IN EXCELLENT AGREEMENT WITH A BROAD MIDLVL
SHORTWAVE MOVING ACROSS THE PACIFIC NW EARLY IN THE PERIOD. SEASONAL
WARMTH WILL OCCUR IN ADVANCE OF THIS FEATURE WITH H7 TEMPS AROUND 10
TO 14 C PER THE GFS ON SAT. CONSIDERABLE 700-300 MILLIBAR MOISTURE
AND INCREASING QG ASCENT WITH THE APPROACHING WAVE WOULD SUGGEST AN
INCREASE IN SHOWER AND TSTM ACTIVITY...EVEN AT NON DIURNALLY FAVORED
TIMES OF DAY. DO NOT EXPECT A WASHOUT BY ANY MEANS...BUT THERE WILL
PROBABLY BE CONVECTION AROUND. LOOKING A BIT BREEZY EACH AFTN OVER
THE HOLIDAY WEEKEND...ESPECIALLY WEST OF THE LARAMIE RANGE WITH AN
INCREASE IN HEIGHT GRADIENTS ALOFT AND THE SFC LOW PASSING ACROSS
NORTHERN WY. COOLER ON SUN/MON AS THE UPPER-LEVEL SYSTEM MOVES
OVERHEAD. THE ECMWF SHOWS 1000-500 MILLIBAR THICKNESSES FALLING TO
AROUND 570 DM...AND MOS GUIDANCE SUGGESTS SFC TEMPS WILL BE A GOOD
10 TO 15 DEGREES COOLER WHEN COMPARED TO SAT. AN UNSETTLED WEATHER
PATTERN WILL PERSIST THRU EARLY NEXT WEEK WITH DISTURBANCES EMBEDDED
WITHIN QUASI-ZONAL FLOW. WEAK UPPER-LEVEL RIDGING SHOULD GIVE WAY TO
A GRADUAL WARMING TREND THROUGH MIDWEEK WITH LESSER CHANCES FOR PCPN
FROM TUE ONWARD.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY EVENING)
ISSUED AT 1008 PM MDT WED AUG 27 2014

ISOLATED TO SCATTERED SHOWERS THE REST OF THE NIGHT. AREAS OF LOW
CLOUDS AND FOG DEVELOPING OVERNIGHT PRODUCING IFR...OTHERWISE VFR
PREVAILS. FOG AND LOW CLOUDS LIFTING BY MID MORNING THURSDAY.
VFR PREVAILS ON THURSDAY WITH LOCALIZED MVFR IN ISOLATED TO
SCATTERED SHOWERS AND THUNDERSTORMS THURSDAY AFTERNOON SOUTH OF A
RAWLINS TO SCOTTSBLUFF LINE.

&&

.FIRE WEATHER...
ISSUED AT 413 PM MDT WED AUG 27 2014

NUMEROUS SHOWERS AND SCATTERED THUNDERSTORMS WILL
CONTINUE OVER THE DISTRICT THIS AFTERNOON AND TONIGHT. THIS
ACTIVITY WILL PRODUCE MODERATE TO HEAVY RAIN AND PERHAPS SOME
SMALL HAIL AS WELL. A MORE ISOLATED COVERAGE FOR SHOWERS AND
T-STORMS IS EXPECTED FOR THURSDAY...WITH THE MAIN FOCUS FOR THIS
ACTIVITY IN THE MOUNTAINS AND NEAR THE COLORADO BORDER. DRIER AND
WARMER WEATHER WILL RETURN FRIDAY AND CONTINUE THIS
WEEKEND...ALONG WITH GUSTY WEST TO SOUTHWEST WINDS. THERE WILL BE
A SLIGHT CHANCE FOR SHOWERS AND THUNDERSTORMS LATE SUNDAY AND LABOR
DAY WITH THE PASSAGE OF A UPPER LEVEL TROUGH AND PACIFIC COLD
FRONT.

&&

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

$$

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







000
FXUS65 KCYS 280241
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
841 PM MDT WED AUG 27 2014

.UPDATE...
ISSUED AT 839 PM MDT WED AUG 27 2014

SHORTWAVE TROUGH ALOFT MOVES SLOWLY EASTWARD TO WESTERN NEBRASKA
AND NORTHEAST COLORADO BY DAWN...WITH ENOUGH LOW AND MID LEVEL
MOISTURE FOR ISOLATED TO SCATTERED SHOWERS. AREAS OF FOG LIKELY
OVERNIGHT LOOKING AT PROJECTED TEMPERATURE AND DEWPOINT SPREADS.

&&

.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 413 PM MDT WED AUG 27 2014

THE STRONG UPPER LOW IS MOVING INTO WESTERN COLORADO THIS
AFTERNOON AS SEEN ON WATER VAPOR IMAGERY. A POTENT SHORTWAVE
MOVED OUT AHEAD OF THE LOW AND OVER THE FORECAST AREA THIS
MORNING...SPARKING OFF NUMEROUS SHOWERS AND TSTORMS MAINLY ALONG
AND EAST OF THE LARAMIE RANGE. SOME TRAINING OF STORMS WAS OBSERVED
ALONG A SFC BOUNDARY THAT WAS SITUATED NEAR THE WY/NE BORDER
EARLIER...WITH MODERATE TO HEAVY RAIN OBSERVED WITH THE
THUNDERSTORM ACTIVITY. SOME MINOR TO MODERATE FLOODING OCCURRED
ACROSS CENTRAL GOSHEN COUNTY WITHIN THE AREA OF TRAINING STORMS.
THAT BOUNDARY HAS SINCE PUSHED OFF TO THE SOUTH AND EAST...LIKELY
WITH THE HELP OF THUNDERSTORM OUTFLOW AND AS SFC CYCLOGENESIS IS
OCCURRING IN SOUTHEAST COLORADO...ACCELERATING THE SOUTHWARD
MOVEMENT OF THE BOUNDARY. THE BULK OF THE THUNDERSTORM ACTIVITY IS
NOW OVER FAR NORTHERN AND EASTERN PORTIONS OF THE PANHANDLE THIS
AFTERNOON ON THE LEADING EDGE OF THE SHORTWAVE...WITH THE HEAVIEST
RAIN EXPECTED TO PUSH OFF TO THE EAST-NORTHEAST THROUGH THE
EVENING. ANOTHER ROUND OF SHOWERS AND STORMS ARE MOVING UP FROM
THE SOUTHWEST ON THE NOSE OF A JETLET ROUNDING THE BASE OF THE
TROUGH. THIS ACTIVITY IS OCCURRING WITHIN A DRIER AIRMASS PER
WATER VAPOR IMAGERY...SO RAIN RATES SHOULD BE LESS OVERALL.
INCREASING SOLAR INSOLATION OVER THE NEXT FEW HOURS COULD HELP
DESTABILIZE THE ATMOSPHERE SOMEWHAT ACROSS THE WYO PLAINS...SO
CANNOT RULE OUT THE IDEA THAT THESE STORMS MOVING OFF THE MOUNTAINS
COULD BECOME STRONG WITH THE HELP OF THE APPROACHING JET. HOWEVER THE
ATMOSPHERE IS FAIRLY WORKED OVER FROM EARLIER ACTIVITY SO NOT
WHOLLY CONFIDENT STORMS WILL INTENSIFY MUCH.

THE UPPER LOW WILL CONTINUE TO TREK SOUTHEAST INTO THE CENTRAL
PLAINS THROUGH THURSDAY...WITH WRAPAROUND ENERGY AND MOISTURE
MAINTAINING CHANCES FOR SHOWERS AND TSTORMS ACROSS THE CWA TONIGHT.
MIDLEVEL CONVERGENCE WITHIN THE TROUGH AXIS WILL MOVE OVERHEAD ON
THURSDAY...WITH THE ADDITION OF BROADSCALE LIFT WITHIN THE LEFT
ENTRANCE OF THE CURVED JET AIDING IN DEVELOPMENT OF CONVECTION
THROUGH THE DAY. THE MAIN FOCUS WILL BE SOUTH OF A RAWLINS-LUSK-
CHADRON LINE. MUCH DRIER AIR WILL FILTER IN FROM THE NORTHWEST AS
A SHORTWAVE RIDGE MOVES OVERHEAD THURSDAY NIGHT AND EARLY
FRIDAY...WITH A WEAK WAVE APPROACHING FROM THE NORTHWEST FRIDAY
AFTERNOON. A FEW WEAK TSTORMS ARE POSSIBLE IN THE AFTERNOON AS THE
WAVE APPROACHES.

.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 413 PM MDT WED AUG 27 2014

MEDIUM RANGE MODELS ARE IN EXCELLENT AGREEMENT WITH A BROAD MIDLVL
SHORTWAVE MOVING ACROSS THE PACIFIC NW EARLY IN THE PERIOD. SEASONAL
WARMTH WILL OCCUR IN ADVANCE OF THIS FEATURE WITH H7 TEMPS AROUND 10
TO 14 C PER THE GFS ON SAT. CONSIDERABLE 700-300 MILLIBAR MOISTURE
AND INCREASING QG ASCENT WITH THE APPROACHING WAVE WOULD SUGGEST AN
INCREASE IN SHOWER AND TSTM ACTIVITY...EVEN AT NON DIURNALLY FAVORED
TIMES OF DAY. DO NOT EXPECT A WASHOUT BY ANY MEANS...BUT THERE WILL
PROBABLY BE CONVECTION AROUND. LOOKING A BIT BREEZY EACH AFTN OVER
THE HOLIDAY WEEKEND...ESPECIALLY WEST OF THE LARAMIE RANGE WITH AN
INCREASE IN HEIGHT GRADIENTS ALOFT AND THE SFC LOW PASSING ACROSS
NORTHERN WY. COOLER ON SUN/MON AS THE UPPER-LEVEL SYSTEM MOVES
OVERHEAD. THE ECMWF SHOWS 1000-500 MILLIBAR THICKNESSES FALLING TO
AROUND 570 DM...AND MOS GUIDANCE SUGGESTS SFC TEMPS WILL BE A GOOD
10 TO 15 DEGREES COOLER WHEN COMPARED TO SAT. AN UNSETTLED WEATHER
PATTERN WILL PERSIST THRU EARLY NEXT WEEK WITH DISTURBANCES EMBEDDED
WITHIN QUASI-ZONAL FLOW. WEAK UPPER-LEVEL RIDGING SHOULD GIVE WAY TO
A GRADUAL WARMING TREND THROUGH MIDWEEK WITH LESSER CHANCES FOR PCPN
FROM TUE ONWARD.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY AFTERNOON)
ISSUED AT 526 PM MDT WED AUG 27 2014

ISOLATED THUNDERSTORMS THROUGH 03Z...PRODUCING WIND GUSTS TO 45 KNOTS
ALONG WITH MVFR AND TURBULENCE...THEN AREAS OF IFR CEILINGS AND
VISIBILITIES DEVELOPING AFTER MIDNIGHT WITH FOG DEVELOPMENT.

VFR ON THURSDAY WITH ISOLATED TO SCATTERED SHOWERS AND
THUNDERSTORMS ALONG AND NEAR THE COLORADO BORDER.


&&

.FIRE WEATHER...
ISSUED AT 413 PM MDT WED AUG 27 2014

NUMEROUS SHOWERS AND SCATTERED THUNDERSTORMS WILL
CONTINUE OVER THE DISTRICT THIS AFTERNOON AND TONIGHT. THIS
ACTIVITY WILL PRODUCE MODERATE TO HEAVY RAIN AND PERHAPS SOME
SMALL HAIL AS WELL. A MORE ISOLATED COVERAGE FOR SHOWERS AND
T-STORMS IS EXPECTED FOR THURSDAY...WITH THE MAIN FOCUS FOR THIS
ACTIVITY IN THE MOUNTAINS AND NEAR THE COLORADO BORDER. DRIER AND
WARMER WEATHER WILL RETURN FRIDAY AND CONTINUE THIS
WEEKEND...ALONG WITH GUSTY WEST TO SOUTHWEST WINDS. THERE WILL BE
A SLIGHT CHANCE FOR SHOWERS AND THUNDERSTORMS LATE SUNDAY AND LABOR
DAY WITH THE PASSAGE OF A UPPER LEVEL TROUGH AND PACIFIC COLD
FRONT.

&&

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

$$

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






000
FXUS63 KUNR 280005
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
605 PM MDT WED AUG 27 2014

.UPDATE...
ISSUED AT 601 PM MDT WED AUG 27 2014

WDSPRD SHRA/TSRA CONTINUES TO LIFT NEWD ACROSS NERN THROUGH SWRN
SD...SO HAVE RAISED POPS SIGNIFICANTLY FOR THIS EVENING THAT AREA...WHILE
ALSO EXPANDING POPS A BIT FURTHER NORTH. SOME OF THIS RAINFALL IS
VERY HEAVY.

&&

.SHORT TERM...THIS EVENING THROUGH THURSDAY NIGHT
ISSUED AT 305 PM MDT WED AUG 27 2014

CURRENT SURFACE ANALYSIS SHOWS LOW PRESSURE OVER FAR NORTHEAST
CO...WITH A NEARLY STATIONARY FRONTAL BOUNDARY FROM SOUTHERN WY TO
CENTRAL KS. UPPER LEVEL ANALYSIS SHOWS LOW PRESSURE OVER NORTHWEST
CO...WITH TROF COVERING THE ROCKIES AND MUCH OF THE HIGH PLAINS.
SKIES HAVE BECOME MOSTLY CLOUDY ACROSS MUCH OF THE AREA...EXCEPT
FOR FAR NORTHWESTERN SD. REGIONAL RADARS SHOW MAIN BAND OF SHOWERS
AND STORMS ROTATING NORTH-NORTHEAST AROUND UPPER LOW ACROSS MUCH
OF EASTERN WY...THE NEB PANHANDLE...AND INTO FAR SOUTHWESTERN SD.
SCATTERED SHOWERS AND STORMS HAVE DEVELOPED ELSEWHERE ACROSS
SOUTHWEST AND SOUTH CENTRAL SD...AS WELL AS OVER THE BLACK HILLS.
SLOW MOVING STORMS OVER WESTERN PORTIONS OF THE BLACK HILLS HAVE
PRODUCED SOME LOCALLY HEAVY RAINFALL EARLY THIS AFTERNOON.
TEMPERATURES ARE IN THE UPPER 60S AND 70S WITH SOUTHEASTERLY
WINDS.

THE GENERAL TREND FOR SCATTERED TO NUMEROUS SHOWERS AND
THUNDERSTORMS SHOULD CONTINUE INTO TONIGHT ACROSS SOUTHERN PORTIONS
OF THE CWA AS THE UPPER LOW MOVES SLOWLY EAST INTO THE CENTRAL HIGH
PLAINS BY EARLY THURSDAY. THERE WILL BE A FAIRLY SHARP CUT-OFF TO
THE COVERAGE OF SHOWERS THROUGH THE EVENING...GENERALLY SOUTH OF
INTERSTATE 90. THE THREAT FOR SEVERE STORMS REMAINS LOW WITH MAIN
AREA OF INSTABILITY STAYING SOUTH OF THE FORECAST AREA AND WEAK
SHEAR IN PLACE. HOWEVER...THERE IS A THREAT FOR LOCALLY HEAVY
RAINFALL ACROSS SOUTHERN AREAS THIS EVENING...ESPECIALLY OVER FAR
SOUTHWEST INTO SOUTH CENTRAL SD...WHERE PRECIPITABLE WATER VALUES
WILL BE WELL ABOVE AVERAGE AND A COMPLEX OF STORMS COULD MOVE
THROUGH DURING THE EVENING. WITH A LOT OF LOW LEVEL MOISTURE AROUND
THE AREA AND LIGHT WINDS OVERNIGHT...WILL ADD AREAS OF FOG TO MUCH
OF THE WESTERN AND SOUTH CENTRAL SD PLAINS LATE TONIGHT INTO EARLY
THURSDAY.

AS THE UPPER LOW MOVES SLOWLY ACROSS THE CENTRAL HIGH PLAINS LATE
TONIGHT AND THURSDAY...CHANCES FOR SHOWERS AND STORMS SHOULD MOSTLY
BE LIMITED TO THE SOUTH CENTRAL SD AREA. WILL ADD A SLIGHT CHANCE
FOR SHOWERS AND STORMS TO THE CENTRAL AND SOUTHERN BLACK HILLS FOR
THE AFTERNOON WITH SOME LINGERING INSTABILITY AROUND POSSIBLY
PRODUCING A TERRAIN INDUCED SHOWER OR STORM. SKIES WILL BE VARIABLY
CLOUDY...WITH THE MOST SUN ACROSS NORTHERN AND WESTERN PORTIONS OF
THE CWA. WARMER AIR CAN BE EXPECTED ON THURSDAY...ESPECIALLY
ACROSS THESE NORTHERN AND WESTERN AREAS. HIGHS SHOULD RANGE FROM THE
MID 70S TO MID 80S.

CLOUDS WILL CONTINUE TO GRADUALLY DECREASE FROM NORTHWEST TO
SOUTHEAST LATE THURSDAY INTO THURSDAY NIGHT...WITH MOSTLY CLEAR
SKIES OVERNIGHT. SOME FOG COULD AGAIN BE POSSIBLE OVER THE SD PLAINS
LATE...BUT WILL TAKE A CLOSER LOOK AT THAT TOMORROW. LOWS WILL BE IN
THE 50S AND LOWER 60S WITH MOSTLY LIGHT AND VARIABLE WINDS.

&&

.LONG TERM...FRIDAY THROUGH WEDNESDAY
ISSUED AT 305 PM MDT WED AUG 27 2014

FRIDAY...A SHORTWAVE WILL MOVE ACROSS MT/ND PUSHING A COLD FRONT
SOUTH OF THE CWA AS HIGH PRESSURE BUILDS IN OVER SOUTH CENTRAL
CANADA. DEPENDING ON THE AMOUNT OF LOW LEVEL SUBSIDENCE BEHIND THE
SHORTWAVE...A NARROW BAND OF SUFFICIENT CAPE/SHEAR PRESENT FOR
POST FRONTAL ISOLATED STRONG/SEVERE STORMS ACROSS NORTHWEST HALF
OF CWA...BUT CONFIDENCE LOW. TEMPERATURES WILL BE TRICKY WITH WEAK
COOL AIR ADVECTION.

SATURDAY...ANOTHER SHORTWAVE WILL MOVE ACROSS SOUTHERN MT/NORTHERN
WY AHEAD OF LEE TROUGH...WHICH WILL DEVELOP A LOW ALONG IT IN
SOUTHEAST MT AND DRAG ANOTHER COLD FRONT THROUGH THE CWA SATURDAY
NIGHT. SUFFICIENT CAPE/SHEAR WILL BE PRESENT FOR STRONG/SEVERE
STORMS...BUT MLCIN MAY BE NOTABLE GIVEN DEVELOPING THERMAL RIDGE
AHEAD OF SHORTWAVE. TEMPERATURES WILL BE NEAR NORMAL.

HAVE ADDED/EXPANDED POPS BOTH FRIDAY/SATURDAY TO ACCOUNT FOR LATEST
THINKING.

SUNDAY THROUGH WEDNESDAY...ACTIVE PATTERN CONTINUES WITH NORTHWEST
FLOW ALOFT SUNDAY THROUGH TUESDAY...WITH A SLOW TRANSITION TO
RIDGING ACROSS THE NORTHERN PLAINS FOR THE MIDDLE OF THE WEEK.
COOLISH TEMPERATURES TO START SUNDAY BEHIND SATURDAY/S COOL
FRONT...BUT THEN WARMING BACK TO NEAR NORMAL FOR THE MIDDLE OF NEXT
WEEK.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 601 PM MDT WED AUG 27 2014

WDSPRD SHRA/TSRA EXPECTED ACROSS SOUTHERN HALF OF AREA THROUGH
TONIGHT. LOCAL IFR CIGS/VSBYS EXPECTED WITH THE HEAVIER
PRECIPITATION. AREAS ST/BR ALSO EXPECTED THROUGH THE PERIOD
ALONG/SOUTH OF A LINE FROM KPHP TO KCUT...ALTHOUGH FINAL NORTHERN
EDGE OF ST/BR WILL BE LARGELY DEPENDENT ON HOW FAR NORTH
PRECIPITATION DEVELOPS. NORTHERN HALF OF CWA SHOULD REMAIN LARGELY
VFR THROUGH THE PERIOD...ALTHOUGH AREAS MVFR CONDITIONS DUE TO SHRA/BR ARE
POSSIBLE LATE TONIGHT ON THE SD PLAINS AS SURFACE T/TD SPREADS
CONVERGE.

&&

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

$$

UPDATE...JOHNSON
SHORT TERM...26
LONG TERM...HELGESON
AVIATION...JOHNSON







000
FXUS63 KUNR 280005
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
605 PM MDT WED AUG 27 2014

.UPDATE...
ISSUED AT 601 PM MDT WED AUG 27 2014

WDSPRD SHRA/TSRA CONTINUES TO LIFT NEWD ACROSS NERN THROUGH SWRN
SD...SO HAVE RAISED POPS SIGNIFICANTLY FOR THIS EVENING THAT AREA...WHILE
ALSO EXPANDING POPS A BIT FURTHER NORTH. SOME OF THIS RAINFALL IS
VERY HEAVY.

&&

.SHORT TERM...THIS EVENING THROUGH THURSDAY NIGHT
ISSUED AT 305 PM MDT WED AUG 27 2014

CURRENT SURFACE ANALYSIS SHOWS LOW PRESSURE OVER FAR NORTHEAST
CO...WITH A NEARLY STATIONARY FRONTAL BOUNDARY FROM SOUTHERN WY TO
CENTRAL KS. UPPER LEVEL ANALYSIS SHOWS LOW PRESSURE OVER NORTHWEST
CO...WITH TROF COVERING THE ROCKIES AND MUCH OF THE HIGH PLAINS.
SKIES HAVE BECOME MOSTLY CLOUDY ACROSS MUCH OF THE AREA...EXCEPT
FOR FAR NORTHWESTERN SD. REGIONAL RADARS SHOW MAIN BAND OF SHOWERS
AND STORMS ROTATING NORTH-NORTHEAST AROUND UPPER LOW ACROSS MUCH
OF EASTERN WY...THE NEB PANHANDLE...AND INTO FAR SOUTHWESTERN SD.
SCATTERED SHOWERS AND STORMS HAVE DEVELOPED ELSEWHERE ACROSS
SOUTHWEST AND SOUTH CENTRAL SD...AS WELL AS OVER THE BLACK HILLS.
SLOW MOVING STORMS OVER WESTERN PORTIONS OF THE BLACK HILLS HAVE
PRODUCED SOME LOCALLY HEAVY RAINFALL EARLY THIS AFTERNOON.
TEMPERATURES ARE IN THE UPPER 60S AND 70S WITH SOUTHEASTERLY
WINDS.

THE GENERAL TREND FOR SCATTERED TO NUMEROUS SHOWERS AND
THUNDERSTORMS SHOULD CONTINUE INTO TONIGHT ACROSS SOUTHERN PORTIONS
OF THE CWA AS THE UPPER LOW MOVES SLOWLY EAST INTO THE CENTRAL HIGH
PLAINS BY EARLY THURSDAY. THERE WILL BE A FAIRLY SHARP CUT-OFF TO
THE COVERAGE OF SHOWERS THROUGH THE EVENING...GENERALLY SOUTH OF
INTERSTATE 90. THE THREAT FOR SEVERE STORMS REMAINS LOW WITH MAIN
AREA OF INSTABILITY STAYING SOUTH OF THE FORECAST AREA AND WEAK
SHEAR IN PLACE. HOWEVER...THERE IS A THREAT FOR LOCALLY HEAVY
RAINFALL ACROSS SOUTHERN AREAS THIS EVENING...ESPECIALLY OVER FAR
SOUTHWEST INTO SOUTH CENTRAL SD...WHERE PRECIPITABLE WATER VALUES
WILL BE WELL ABOVE AVERAGE AND A COMPLEX OF STORMS COULD MOVE
THROUGH DURING THE EVENING. WITH A LOT OF LOW LEVEL MOISTURE AROUND
THE AREA AND LIGHT WINDS OVERNIGHT...WILL ADD AREAS OF FOG TO MUCH
OF THE WESTERN AND SOUTH CENTRAL SD PLAINS LATE TONIGHT INTO EARLY
THURSDAY.

AS THE UPPER LOW MOVES SLOWLY ACROSS THE CENTRAL HIGH PLAINS LATE
TONIGHT AND THURSDAY...CHANCES FOR SHOWERS AND STORMS SHOULD MOSTLY
BE LIMITED TO THE SOUTH CENTRAL SD AREA. WILL ADD A SLIGHT CHANCE
FOR SHOWERS AND STORMS TO THE CENTRAL AND SOUTHERN BLACK HILLS FOR
THE AFTERNOON WITH SOME LINGERING INSTABILITY AROUND POSSIBLY
PRODUCING A TERRAIN INDUCED SHOWER OR STORM. SKIES WILL BE VARIABLY
CLOUDY...WITH THE MOST SUN ACROSS NORTHERN AND WESTERN PORTIONS OF
THE CWA. WARMER AIR CAN BE EXPECTED ON THURSDAY...ESPECIALLY
ACROSS THESE NORTHERN AND WESTERN AREAS. HIGHS SHOULD RANGE FROM THE
MID 70S TO MID 80S.

CLOUDS WILL CONTINUE TO GRADUALLY DECREASE FROM NORTHWEST TO
SOUTHEAST LATE THURSDAY INTO THURSDAY NIGHT...WITH MOSTLY CLEAR
SKIES OVERNIGHT. SOME FOG COULD AGAIN BE POSSIBLE OVER THE SD PLAINS
LATE...BUT WILL TAKE A CLOSER LOOK AT THAT TOMORROW. LOWS WILL BE IN
THE 50S AND LOWER 60S WITH MOSTLY LIGHT AND VARIABLE WINDS.

&&

.LONG TERM...FRIDAY THROUGH WEDNESDAY
ISSUED AT 305 PM MDT WED AUG 27 2014

FRIDAY...A SHORTWAVE WILL MOVE ACROSS MT/ND PUSHING A COLD FRONT
SOUTH OF THE CWA AS HIGH PRESSURE BUILDS IN OVER SOUTH CENTRAL
CANADA. DEPENDING ON THE AMOUNT OF LOW LEVEL SUBSIDENCE BEHIND THE
SHORTWAVE...A NARROW BAND OF SUFFICIENT CAPE/SHEAR PRESENT FOR
POST FRONTAL ISOLATED STRONG/SEVERE STORMS ACROSS NORTHWEST HALF
OF CWA...BUT CONFIDENCE LOW. TEMPERATURES WILL BE TRICKY WITH WEAK
COOL AIR ADVECTION.

SATURDAY...ANOTHER SHORTWAVE WILL MOVE ACROSS SOUTHERN MT/NORTHERN
WY AHEAD OF LEE TROUGH...WHICH WILL DEVELOP A LOW ALONG IT IN
SOUTHEAST MT AND DRAG ANOTHER COLD FRONT THROUGH THE CWA SATURDAY
NIGHT. SUFFICIENT CAPE/SHEAR WILL BE PRESENT FOR STRONG/SEVERE
STORMS...BUT MLCIN MAY BE NOTABLE GIVEN DEVELOPING THERMAL RIDGE
AHEAD OF SHORTWAVE. TEMPERATURES WILL BE NEAR NORMAL.

HAVE ADDED/EXPANDED POPS BOTH FRIDAY/SATURDAY TO ACCOUNT FOR LATEST
THINKING.

SUNDAY THROUGH WEDNESDAY...ACTIVE PATTERN CONTINUES WITH NORTHWEST
FLOW ALOFT SUNDAY THROUGH TUESDAY...WITH A SLOW TRANSITION TO
RIDGING ACROSS THE NORTHERN PLAINS FOR THE MIDDLE OF THE WEEK.
COOLISH TEMPERATURES TO START SUNDAY BEHIND SATURDAY/S COOL
FRONT...BUT THEN WARMING BACK TO NEAR NORMAL FOR THE MIDDLE OF NEXT
WEEK.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 601 PM MDT WED AUG 27 2014

WDSPRD SHRA/TSRA EXPECTED ACROSS SOUTHERN HALF OF AREA THROUGH
TONIGHT. LOCAL IFR CIGS/VSBYS EXPECTED WITH THE HEAVIER
PRECIPITATION. AREAS ST/BR ALSO EXPECTED THROUGH THE PERIOD
ALONG/SOUTH OF A LINE FROM KPHP TO KCUT...ALTHOUGH FINAL NORTHERN
EDGE OF ST/BR WILL BE LARGELY DEPENDENT ON HOW FAR NORTH
PRECIPITATION DEVELOPS. NORTHERN HALF OF CWA SHOULD REMAIN LARGELY
VFR THROUGH THE PERIOD...ALTHOUGH AREAS MVFR CONDITIONS DUE TO SHRA/BR ARE
POSSIBLE LATE TONIGHT ON THE SD PLAINS AS SURFACE T/TD SPREADS
CONVERGE.

&&

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

$$

UPDATE...JOHNSON
SHORT TERM...26
LONG TERM...HELGESON
AVIATION...JOHNSON







000
FXUS63 KUNR 280005
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
605 PM MDT WED AUG 27 2014

.UPDATE...
ISSUED AT 601 PM MDT WED AUG 27 2014

WDSPRD SHRA/TSRA CONTINUES TO LIFT NEWD ACROSS NERN THROUGH SWRN
SD...SO HAVE RAISED POPS SIGNIFICANTLY FOR THIS EVENING THAT AREA...WHILE
ALSO EXPANDING POPS A BIT FURTHER NORTH. SOME OF THIS RAINFALL IS
VERY HEAVY.

&&

.SHORT TERM...THIS EVENING THROUGH THURSDAY NIGHT
ISSUED AT 305 PM MDT WED AUG 27 2014

CURRENT SURFACE ANALYSIS SHOWS LOW PRESSURE OVER FAR NORTHEAST
CO...WITH A NEARLY STATIONARY FRONTAL BOUNDARY FROM SOUTHERN WY TO
CENTRAL KS. UPPER LEVEL ANALYSIS SHOWS LOW PRESSURE OVER NORTHWEST
CO...WITH TROF COVERING THE ROCKIES AND MUCH OF THE HIGH PLAINS.
SKIES HAVE BECOME MOSTLY CLOUDY ACROSS MUCH OF THE AREA...EXCEPT
FOR FAR NORTHWESTERN SD. REGIONAL RADARS SHOW MAIN BAND OF SHOWERS
AND STORMS ROTATING NORTH-NORTHEAST AROUND UPPER LOW ACROSS MUCH
OF EASTERN WY...THE NEB PANHANDLE...AND INTO FAR SOUTHWESTERN SD.
SCATTERED SHOWERS AND STORMS HAVE DEVELOPED ELSEWHERE ACROSS
SOUTHWEST AND SOUTH CENTRAL SD...AS WELL AS OVER THE BLACK HILLS.
SLOW MOVING STORMS OVER WESTERN PORTIONS OF THE BLACK HILLS HAVE
PRODUCED SOME LOCALLY HEAVY RAINFALL EARLY THIS AFTERNOON.
TEMPERATURES ARE IN THE UPPER 60S AND 70S WITH SOUTHEASTERLY
WINDS.

THE GENERAL TREND FOR SCATTERED TO NUMEROUS SHOWERS AND
THUNDERSTORMS SHOULD CONTINUE INTO TONIGHT ACROSS SOUTHERN PORTIONS
OF THE CWA AS THE UPPER LOW MOVES SLOWLY EAST INTO THE CENTRAL HIGH
PLAINS BY EARLY THURSDAY. THERE WILL BE A FAIRLY SHARP CUT-OFF TO
THE COVERAGE OF SHOWERS THROUGH THE EVENING...GENERALLY SOUTH OF
INTERSTATE 90. THE THREAT FOR SEVERE STORMS REMAINS LOW WITH MAIN
AREA OF INSTABILITY STAYING SOUTH OF THE FORECAST AREA AND WEAK
SHEAR IN PLACE. HOWEVER...THERE IS A THREAT FOR LOCALLY HEAVY
RAINFALL ACROSS SOUTHERN AREAS THIS EVENING...ESPECIALLY OVER FAR
SOUTHWEST INTO SOUTH CENTRAL SD...WHERE PRECIPITABLE WATER VALUES
WILL BE WELL ABOVE AVERAGE AND A COMPLEX OF STORMS COULD MOVE
THROUGH DURING THE EVENING. WITH A LOT OF LOW LEVEL MOISTURE AROUND
THE AREA AND LIGHT WINDS OVERNIGHT...WILL ADD AREAS OF FOG TO MUCH
OF THE WESTERN AND SOUTH CENTRAL SD PLAINS LATE TONIGHT INTO EARLY
THURSDAY.

AS THE UPPER LOW MOVES SLOWLY ACROSS THE CENTRAL HIGH PLAINS LATE
TONIGHT AND THURSDAY...CHANCES FOR SHOWERS AND STORMS SHOULD MOSTLY
BE LIMITED TO THE SOUTH CENTRAL SD AREA. WILL ADD A SLIGHT CHANCE
FOR SHOWERS AND STORMS TO THE CENTRAL AND SOUTHERN BLACK HILLS FOR
THE AFTERNOON WITH SOME LINGERING INSTABILITY AROUND POSSIBLY
PRODUCING A TERRAIN INDUCED SHOWER OR STORM. SKIES WILL BE VARIABLY
CLOUDY...WITH THE MOST SUN ACROSS NORTHERN AND WESTERN PORTIONS OF
THE CWA. WARMER AIR CAN BE EXPECTED ON THURSDAY...ESPECIALLY
ACROSS THESE NORTHERN AND WESTERN AREAS. HIGHS SHOULD RANGE FROM THE
MID 70S TO MID 80S.

CLOUDS WILL CONTINUE TO GRADUALLY DECREASE FROM NORTHWEST TO
SOUTHEAST LATE THURSDAY INTO THURSDAY NIGHT...WITH MOSTLY CLEAR
SKIES OVERNIGHT. SOME FOG COULD AGAIN BE POSSIBLE OVER THE SD PLAINS
LATE...BUT WILL TAKE A CLOSER LOOK AT THAT TOMORROW. LOWS WILL BE IN
THE 50S AND LOWER 60S WITH MOSTLY LIGHT AND VARIABLE WINDS.

&&

.LONG TERM...FRIDAY THROUGH WEDNESDAY
ISSUED AT 305 PM MDT WED AUG 27 2014

FRIDAY...A SHORTWAVE WILL MOVE ACROSS MT/ND PUSHING A COLD FRONT
SOUTH OF THE CWA AS HIGH PRESSURE BUILDS IN OVER SOUTH CENTRAL
CANADA. DEPENDING ON THE AMOUNT OF LOW LEVEL SUBSIDENCE BEHIND THE
SHORTWAVE...A NARROW BAND OF SUFFICIENT CAPE/SHEAR PRESENT FOR
POST FRONTAL ISOLATED STRONG/SEVERE STORMS ACROSS NORTHWEST HALF
OF CWA...BUT CONFIDENCE LOW. TEMPERATURES WILL BE TRICKY WITH WEAK
COOL AIR ADVECTION.

SATURDAY...ANOTHER SHORTWAVE WILL MOVE ACROSS SOUTHERN MT/NORTHERN
WY AHEAD OF LEE TROUGH...WHICH WILL DEVELOP A LOW ALONG IT IN
SOUTHEAST MT AND DRAG ANOTHER COLD FRONT THROUGH THE CWA SATURDAY
NIGHT. SUFFICIENT CAPE/SHEAR WILL BE PRESENT FOR STRONG/SEVERE
STORMS...BUT MLCIN MAY BE NOTABLE GIVEN DEVELOPING THERMAL RIDGE
AHEAD OF SHORTWAVE. TEMPERATURES WILL BE NEAR NORMAL.

HAVE ADDED/EXPANDED POPS BOTH FRIDAY/SATURDAY TO ACCOUNT FOR LATEST
THINKING.

SUNDAY THROUGH WEDNESDAY...ACTIVE PATTERN CONTINUES WITH NORTHWEST
FLOW ALOFT SUNDAY THROUGH TUESDAY...WITH A SLOW TRANSITION TO
RIDGING ACROSS THE NORTHERN PLAINS FOR THE MIDDLE OF THE WEEK.
COOLISH TEMPERATURES TO START SUNDAY BEHIND SATURDAY/S COOL
FRONT...BUT THEN WARMING BACK TO NEAR NORMAL FOR THE MIDDLE OF NEXT
WEEK.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 601 PM MDT WED AUG 27 2014

WDSPRD SHRA/TSRA EXPECTED ACROSS SOUTHERN HALF OF AREA THROUGH
TONIGHT. LOCAL IFR CIGS/VSBYS EXPECTED WITH THE HEAVIER
PRECIPITATION. AREAS ST/BR ALSO EXPECTED THROUGH THE PERIOD
ALONG/SOUTH OF A LINE FROM KPHP TO KCUT...ALTHOUGH FINAL NORTHERN
EDGE OF ST/BR WILL BE LARGELY DEPENDENT ON HOW FAR NORTH
PRECIPITATION DEVELOPS. NORTHERN HALF OF CWA SHOULD REMAIN LARGELY
VFR THROUGH THE PERIOD...ALTHOUGH AREAS MVFR CONDITIONS DUE TO SHRA/BR ARE
POSSIBLE LATE TONIGHT ON THE SD PLAINS AS SURFACE T/TD SPREADS
CONVERGE.

&&

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

$$

UPDATE...JOHNSON
SHORT TERM...26
LONG TERM...HELGESON
AVIATION...JOHNSON







000
FXUS63 KUNR 280005
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
605 PM MDT WED AUG 27 2014

.UPDATE...
ISSUED AT 601 PM MDT WED AUG 27 2014

WDSPRD SHRA/TSRA CONTINUES TO LIFT NEWD ACROSS NERN THROUGH SWRN
SD...SO HAVE RAISED POPS SIGNIFICANTLY FOR THIS EVENING THAT AREA...WHILE
ALSO EXPANDING POPS A BIT FURTHER NORTH. SOME OF THIS RAINFALL IS
VERY HEAVY.

&&

.SHORT TERM...THIS EVENING THROUGH THURSDAY NIGHT
ISSUED AT 305 PM MDT WED AUG 27 2014

CURRENT SURFACE ANALYSIS SHOWS LOW PRESSURE OVER FAR NORTHEAST
CO...WITH A NEARLY STATIONARY FRONTAL BOUNDARY FROM SOUTHERN WY TO
CENTRAL KS. UPPER LEVEL ANALYSIS SHOWS LOW PRESSURE OVER NORTHWEST
CO...WITH TROF COVERING THE ROCKIES AND MUCH OF THE HIGH PLAINS.
SKIES HAVE BECOME MOSTLY CLOUDY ACROSS MUCH OF THE AREA...EXCEPT
FOR FAR NORTHWESTERN SD. REGIONAL RADARS SHOW MAIN BAND OF SHOWERS
AND STORMS ROTATING NORTH-NORTHEAST AROUND UPPER LOW ACROSS MUCH
OF EASTERN WY...THE NEB PANHANDLE...AND INTO FAR SOUTHWESTERN SD.
SCATTERED SHOWERS AND STORMS HAVE DEVELOPED ELSEWHERE ACROSS
SOUTHWEST AND SOUTH CENTRAL SD...AS WELL AS OVER THE BLACK HILLS.
SLOW MOVING STORMS OVER WESTERN PORTIONS OF THE BLACK HILLS HAVE
PRODUCED SOME LOCALLY HEAVY RAINFALL EARLY THIS AFTERNOON.
TEMPERATURES ARE IN THE UPPER 60S AND 70S WITH SOUTHEASTERLY
WINDS.

THE GENERAL TREND FOR SCATTERED TO NUMEROUS SHOWERS AND
THUNDERSTORMS SHOULD CONTINUE INTO TONIGHT ACROSS SOUTHERN PORTIONS
OF THE CWA AS THE UPPER LOW MOVES SLOWLY EAST INTO THE CENTRAL HIGH
PLAINS BY EARLY THURSDAY. THERE WILL BE A FAIRLY SHARP CUT-OFF TO
THE COVERAGE OF SHOWERS THROUGH THE EVENING...GENERALLY SOUTH OF
INTERSTATE 90. THE THREAT FOR SEVERE STORMS REMAINS LOW WITH MAIN
AREA OF INSTABILITY STAYING SOUTH OF THE FORECAST AREA AND WEAK
SHEAR IN PLACE. HOWEVER...THERE IS A THREAT FOR LOCALLY HEAVY
RAINFALL ACROSS SOUTHERN AREAS THIS EVENING...ESPECIALLY OVER FAR
SOUTHWEST INTO SOUTH CENTRAL SD...WHERE PRECIPITABLE WATER VALUES
WILL BE WELL ABOVE AVERAGE AND A COMPLEX OF STORMS COULD MOVE
THROUGH DURING THE EVENING. WITH A LOT OF LOW LEVEL MOISTURE AROUND
THE AREA AND LIGHT WINDS OVERNIGHT...WILL ADD AREAS OF FOG TO MUCH
OF THE WESTERN AND SOUTH CENTRAL SD PLAINS LATE TONIGHT INTO EARLY
THURSDAY.

AS THE UPPER LOW MOVES SLOWLY ACROSS THE CENTRAL HIGH PLAINS LATE
TONIGHT AND THURSDAY...CHANCES FOR SHOWERS AND STORMS SHOULD MOSTLY
BE LIMITED TO THE SOUTH CENTRAL SD AREA. WILL ADD A SLIGHT CHANCE
FOR SHOWERS AND STORMS TO THE CENTRAL AND SOUTHERN BLACK HILLS FOR
THE AFTERNOON WITH SOME LINGERING INSTABILITY AROUND POSSIBLY
PRODUCING A TERRAIN INDUCED SHOWER OR STORM. SKIES WILL BE VARIABLY
CLOUDY...WITH THE MOST SUN ACROSS NORTHERN AND WESTERN PORTIONS OF
THE CWA. WARMER AIR CAN BE EXPECTED ON THURSDAY...ESPECIALLY
ACROSS THESE NORTHERN AND WESTERN AREAS. HIGHS SHOULD RANGE FROM THE
MID 70S TO MID 80S.

CLOUDS WILL CONTINUE TO GRADUALLY DECREASE FROM NORTHWEST TO
SOUTHEAST LATE THURSDAY INTO THURSDAY NIGHT...WITH MOSTLY CLEAR
SKIES OVERNIGHT. SOME FOG COULD AGAIN BE POSSIBLE OVER THE SD PLAINS
LATE...BUT WILL TAKE A CLOSER LOOK AT THAT TOMORROW. LOWS WILL BE IN
THE 50S AND LOWER 60S WITH MOSTLY LIGHT AND VARIABLE WINDS.

&&

.LONG TERM...FRIDAY THROUGH WEDNESDAY
ISSUED AT 305 PM MDT WED AUG 27 2014

FRIDAY...A SHORTWAVE WILL MOVE ACROSS MT/ND PUSHING A COLD FRONT
SOUTH OF THE CWA AS HIGH PRESSURE BUILDS IN OVER SOUTH CENTRAL
CANADA. DEPENDING ON THE AMOUNT OF LOW LEVEL SUBSIDENCE BEHIND THE
SHORTWAVE...A NARROW BAND OF SUFFICIENT CAPE/SHEAR PRESENT FOR
POST FRONTAL ISOLATED STRONG/SEVERE STORMS ACROSS NORTHWEST HALF
OF CWA...BUT CONFIDENCE LOW. TEMPERATURES WILL BE TRICKY WITH WEAK
COOL AIR ADVECTION.

SATURDAY...ANOTHER SHORTWAVE WILL MOVE ACROSS SOUTHERN MT/NORTHERN
WY AHEAD OF LEE TROUGH...WHICH WILL DEVELOP A LOW ALONG IT IN
SOUTHEAST MT AND DRAG ANOTHER COLD FRONT THROUGH THE CWA SATURDAY
NIGHT. SUFFICIENT CAPE/SHEAR WILL BE PRESENT FOR STRONG/SEVERE
STORMS...BUT MLCIN MAY BE NOTABLE GIVEN DEVELOPING THERMAL RIDGE
AHEAD OF SHORTWAVE. TEMPERATURES WILL BE NEAR NORMAL.

HAVE ADDED/EXPANDED POPS BOTH FRIDAY/SATURDAY TO ACCOUNT FOR LATEST
THINKING.

SUNDAY THROUGH WEDNESDAY...ACTIVE PATTERN CONTINUES WITH NORTHWEST
FLOW ALOFT SUNDAY THROUGH TUESDAY...WITH A SLOW TRANSITION TO
RIDGING ACROSS THE NORTHERN PLAINS FOR THE MIDDLE OF THE WEEK.
COOLISH TEMPERATURES TO START SUNDAY BEHIND SATURDAY/S COOL
FRONT...BUT THEN WARMING BACK TO NEAR NORMAL FOR THE MIDDLE OF NEXT
WEEK.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 601 PM MDT WED AUG 27 2014

WDSPRD SHRA/TSRA EXPECTED ACROSS SOUTHERN HALF OF AREA THROUGH
TONIGHT. LOCAL IFR CIGS/VSBYS EXPECTED WITH THE HEAVIER
PRECIPITATION. AREAS ST/BR ALSO EXPECTED THROUGH THE PERIOD
ALONG/SOUTH OF A LINE FROM KPHP TO KCUT...ALTHOUGH FINAL NORTHERN
EDGE OF ST/BR WILL BE LARGELY DEPENDENT ON HOW FAR NORTH
PRECIPITATION DEVELOPS. NORTHERN HALF OF CWA SHOULD REMAIN LARGELY
VFR THROUGH THE PERIOD...ALTHOUGH AREAS MVFR CONDITIONS DUE TO SHRA/BR ARE
POSSIBLE LATE TONIGHT ON THE SD PLAINS AS SURFACE T/TD SPREADS
CONVERGE.

&&

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

$$

UPDATE...JOHNSON
SHORT TERM...26
LONG TERM...HELGESON
AVIATION...JOHNSON







000
FXUS65 KCYS 272329
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
529 PM MDT WED AUG 27 2014

.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 413 PM MDT WED AUG 27 2014

THE STRONG UPPER LOW IS MOVING INTO WESTERN COLORADO THIS
AFTERNOON AS SEEN ON WATER VAPOR IMAGERY. A POTENT SHORTWAVE
MOVED OUT AHEAD OF THE LOW AND OVER THE FORECAST AREA THIS
MORNING...SPARKING OFF NUMEROUS SHOWERS AND TSTORMS MAINLY ALONG
AND EAST OF THE LARAMIE RANGE. SOME TRAINING OF STORMS WAS OBSERVED
ALONG A SFC BOUNDARY THAT WAS SITUATED NEAR THE WY/NE BORDER
EARLIER...WITH MODERATE TO HEAVY RAIN OBSERVED WITH THE
THUNDERSTORM ACTIVITY. SOME MINOR TO MODERATE FLOODING OCCURRED
ACROSS CENTRAL GOSHEN COUNTY WITHIN THE AREA OF TRAINING STORMS.
THAT BOUNDARY HAS SINCE PUSHED OFF TO THE SOUTH AND EAST...LIKELY
WITH THE HELP OF THUNDERSTORM OUTFLOW AND AS SFC CYCLOGENESIS IS
OCCURRING IN SOUTHEAST COLORADO...ACCELERATING THE SOUTHWARD
MOVEMENT OF THE BOUNDARY. THE BULK OF THE THUNDERSTORM ACTIVITY IS
NOW OVER FAR NORTHERN AND EASTERN PORTIONS OF THE PANHANDLE THIS
AFTERNOON ON THE LEADING EDGE OF THE SHORTWAVE...WITH THE HEAVIEST
RAIN EXPECTED TO PUSH OFF TO THE EAST-NORTHEAST THROUGH THE
EVENING. ANOTHER ROUND OF SHOWERS AND STORMS ARE MOVING UP FROM
THE SOUTHWEST ON THE NOSE OF A JETLET ROUNDING THE BASE OF THE
TROUGH. THIS ACTIVITY IS OCCURRING WITHIN A DRIER AIRMASS PER
WATER VAPOR IMAGERY...SO RAIN RATES SHOULD BE LESS OVERALL.
INCREASING SOLAR INSOLATION OVER THE NEXT FEW HOURS COULD HELP
DESTABILIZE THE ATMOSPHERE SOMEWHAT ACROSS THE WYO PLAINS...SO
CANNOT RULE OUT THE IDEA THAT THESE STORMS MOVING OFF THE MOUNTAINS
COULD BECOME STRONG WITH THE HELP OF THE APPROACHING JET. HOWEVER THE
ATMOSPHERE IS FAIRLY WORKED OVER FROM EARLIER ACTIVITY SO NOT
WHOLLY CONFIDENT STORMS WILL INTENSIFY MUCH.

THE UPPER LOW WILL CONTINUE TO TREK SOUTHEAST INTO THE CENTRAL
PLAINS THROUGH THURSDAY...WITH WRAPAROUND ENERGY AND MOISTURE
MAINTAINING CHANCES FOR SHOWERS AND TSTORMS ACROSS THE CWA TONIGHT.
MIDLEVEL CONVERGENCE WITHIN THE TROUGH AXIS WILL MOVE OVERHEAD ON
THURSDAY...WITH THE ADDITION OF BROADSCALE LIFT WITHIN THE LEFT
ENTRANCE OF THE CURVED JET AIDING IN DEVELOPMENT OF CONVECTION
THROUGH THE DAY. THE MAIN FOCUS WILL BE SOUTH OF A RAWLINS-LUSK-
CHADRON LINE. MUCH DRIER AIR WILL FILTER IN FROM THE NORTHWEST AS
A SHORTWAVE RIDGE MOVES OVERHEAD THURSDAY NIGHT AND EARLY
FRIDAY...WITH A WEAK WAVE APPROACHING FROM THE NORTHWEST FRIDAY
AFTERNOON. A FEW WEAK TSTORMS ARE POSSIBLE IN THE AFTERNOON AS THE
WAVE APPROACHES.

.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 413 PM MDT WED AUG 27 2014

MEDIUM RANGE MODELS ARE IN EXCELLENT AGREEMENT WITH A BROAD MIDLVL
SHORTWAVE MOVING ACROSS THE PACIFIC NW EARLY IN THE PERIOD. SEASONAL
WARMTH WILL OCCUR IN ADVANCE OF THIS FEATURE WITH H7 TEMPS AROUND 10
TO 14 C PER THE GFS ON SAT. CONSIDERABLE 700-300 MILLIBAR MOISTURE
AND INCREASING QG ASCENT WITH THE APPROACHING WAVE WOULD SUGGEST AN
INCREASE IN SHOWER AND TSTM ACTIVITY...EVEN AT NON DIURNALLY FAVORED
TIMES OF DAY. DO NOT EXPECT A WASHOUT BY ANY MEANS...BUT THERE WILL
PROBABLY BE CONVECTION AROUND. LOOKING A BIT BREEZY EACH AFTN OVER
THE HOLIDAY WEEKEND...ESPECIALLY WEST OF THE LARAMIE RANGE WITH AN
INCREASE IN HEIGHT GRADIENTS ALOFT AND THE SFC LOW PASSING ACROSS
NORTHERN WY. COOLER ON SUN/MON AS THE UPPER-LEVEL SYSTEM MOVES
OVERHEAD. THE ECMWF SHOWS 1000-500 MILLIBAR THICKNESSES FALLING TO
AROUND 570 DM...AND MOS GUIDANCE SUGGESTS SFC TEMPS WILL BE A GOOD
10 TO 15 DEGREES COOLER WHEN COMPARED TO SAT. AN UNSETTLED WEATHER
PATTERN WILL PERSIST THRU EARLY NEXT WEEK WITH DISTURBANCES EMBEDDED
WITHIN QUASI-ZONAL FLOW. WEAK UPPER-LEVEL RIDGING SHOULD GIVE WAY TO
A GRADUAL WARMING TREND THROUGH MIDWEEK WITH LESSER CHANCES FOR PCPN
FROM TUE ONWARD.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY AFTERNOON)
ISSUED AT 526 PM MDT WED AUG 27 2014

ISOLATED THUNDERSTORMS THROUGH 03Z...PRODUCING WIND GUSTS TO 45 KNOTS
ALONG WITH MVFR AND TURBULENCE...THEN AREAS OF IFR CEILINGS AND
VISIBILITIES DEVELOPING AFTER MIDNIGHT WITH FOG DEVELOPMENT.

VFR ON THURSDAY WITH ISOLATED TO SCATTERED SHOWERS AND
THUNDERSTORMS ALONG AND NEAR THE COLORADO BORDER.

&&

.FIRE WEATHER...
ISSUED AT 413 PM MDT WED AUG 27 2014

NUMEROUS SHOWERS AND SCATTERED THUNDERSTORMS WILL
CONTINUE OVER THE DISTRICT THIS AFTERNOON AND TONIGHT. THIS
ACTIVITY WILL PRODUCE MODERATE TO HEAVY RAIN AND PERHAPS SOME
SMALL HAIL AS WELL. A MORE ISOLATED COVERAGE FOR SHOWERS AND
T-STORMS IS EXPECTED FOR THURSDAY...WITH THE MAIN FOCUS FOR THIS
ACTIVITY IN THE MOUNTAINS AND NEAR THE COLORADO BORDER. DRIER AND
WARMER WEATHER WILL RETURN FRIDAY AND CONTINUE THIS
WEEKEND...ALONG WITH GUSTY WEST TO SOUTHWEST WINDS. THERE WILL BE
A SLIGHT CHANCE FOR SHOWERS AND THUNDERSTORMS LATE SUNDAY AND LABOR
DAY WITH THE PASSAGE OF A UPPER LEVEL TROUGH AND PACIFIC COLD
FRONT.

&&

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

$$

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







000
FXUS65 KRIW 272219 CCA
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
143 PM MDT WED AUG 27 2014

.SHORT TERM...TONIGHT AND THURSDAY

MID LEVEL CIRCULATION NEAR MUDDY GAP AT MIDDAY WITH UPPER
CIRCULATION OVER NERN UT MOVING INTO FAR NWRN CO. IMPRESSIVE VWP
SOUNDING TODAY WITH NE FLOW IN THE MID LEVELS AND SE UPPER FLOW.
BAROCLINIC SHIELD OF PCPN MOVED NWWD ALL THE WAY INTO LND AND THE
EDGE OF RIW WITH .14 INCHES OF RAIN IN LANDER BETWEEN 11 AND NOON
AND ANOTHER .05 BETWEEN NOON AND 1 PM. CAMP CREEK RAWS NEAR MUDDY
GAP REPORTED .83 INCHES OF RAIN THIS MORNING (0.85 NOW). EVEN
SOUTH PASS CITY WAS NEARING THREE QUARTERS OF AN INCH AS OF 1PM.
MANY AREAS OVER NERN SWEETWATER COUNTY...SERN/ERN FREMONT AND
WRN/NRN NATRONA HAVE ALSO LIKELY RECEIVED AROUND A HALF OF AN INCH
THIS MORNING WITH RAIN ONGOING. EVEN RIVERTON IS GETTING
MEASURABLE RAIN WITH 0.03 AS OF 130 PM TODAY. CIRCULATION WILL
WEAKEN AND OPEN UP LATER TODAY AND THEN MOVE OFF TO THE EAST
TONIGHT INTO THURSDAY MORNING. SHOWERS AND ISOLATED THUNDERSTORMS
WILL CONTINUE INTO THE EVENING WITH THE HIGHEST PROBABILITY
SHIFTING SEWD. SHORTWAVE RIDGING THEN MOVES IN FOR A DRY AND WARMER
THURSDAY. BL LOOKS MOIST LATE TONIGHT SO COULD DEFINITELY SEE LOW
CLOUDS AND OR FOG IN OUR SERN ZONES WHERE LIGHT WINDS AND RECENT
RAINFALL HELP OUT.

.LONG TERM...THURSDAY NIGHT THROUGH WEDNESDAY

THE TROUGH THAT IS GIVING SOUTHERN AND EAST CENTRAL WYOMING RAIN
TODAY WILL BE EXITING EAST ACROSS THE PLAINS BY THURSDAY NIGHT. THEN
A FAST MOVING SHORTWAVE WILL BE SCOOTING RAPIDLY EAST ACROSS MONTANA
FRIDAY. THE FLOW OVER WYOMING SOUTH OF THIS SHORTWAVE WILL BE
WESTERLY AND SLIGHTLY DIFLUENT. THE LIFT FROM THIS SHORTWAVE WILL
REMAIN TO THE NORTH IN MONTANA. HIGHER CAPES ARE PROGGED FOR JOHNSON
COUNTY FRIDAY ALONG WITH JUST SLIGHTLY NEGATIVE LIFTED INDICES.
MARGINAL AMOUNTS OF MOISTURE ARE PROGGED FOR FAR NORTHERN WY FRIDAY
WITH MOST OF THE 500-700MB MOISTURE REMAINING UP IN MONTANA. WENT
WITH JUST SCATTERED SHOWERS IN THE NORTHERN MTNS FOR FRIDAY AS WELL
AS IN THE WIND RIVER MOUNTAINS.

THE GFS HAS COME MORE IN LINE WITH THE ECMWF IN THAT IT IS BRINGING
A SHORTWAVE/COLD FRONT THROUGH OUR CWA SATURDAY AND ANOTHER ONE ON MONDAY
ALONG WITH THE ASCT LONG WAVE TROUGH TO PASS THROUGH SUNDAY. HAVE
KEPT WIDESPREAD/NUMEROUS SHOWERS AND A FEW THUNDERSTORMS ACROSS THE
AREA FOP SATURDAY ASCT WITH THE SHORTWAVE...ESP IN THE AFTERNOON AND
IN THE NORTHWEST. ELSEWHERE ON SATURDAY AHEAD OF THE COLD
FRONT...WARM...BREEZY AND DRY CONDITIONS ARE EXPECTED...ESPECIALLY
FROM RKS TO CPR...WHERE FIRE WEATHER CONCERNS WILL LIKELY BE SOMEWHAT
ELEVATED. IN FACT...SATURDAY APPEARS TO BE THE WARMEST DAY OF THE
WEEK WITH HIGHS IN THE 80S EXPECTED AT THE LOWER ELEVATIONS EAST OF
THE DIVIDE AND 70S WEST. H7 TEMPS BEHIND THIS TROUGH/COLD FRONT WILL
DROP TO NEAR ZERO IN NORTHERN WY BY SUNDAY WHICH WOULD BRING THE
SNOW LEVEL DOWN TO 8500 FEET IN THE NORTHERN MTNS. MAINLY SCATTERED
SHOWERS ARE EXPECTED FOR COVERAGE SUNDAY WITH THE LONG WAVE TROUGH.
SCATTERED SHOWER ACTIVITY IS STILL EXPECTED MONDAY WITH THE NEXT
SHORTWAVE. NOT MUCH IN THE WAY OF THUNDERSTORM ACTIVITY ANYWHERE IS
EXPECTED AFTER SATURDAY WITH THE STABILIZING AIR MASS...MAINLY JUST
SHOWERS. WITH A CONTINUED WESTERLY...SOMEWHAT MOIST PACIFIC
FLOW...STILL EXPECTING SOME ISOLATED SHOWERS IN THE HIGHEST FAR NW
MTNS TUESDAY. THIS WESTERLY FLOW WILL RESULT IN JUST DRY CONDITIONS
IN MOST AREAS OF THE CWA TUESDAY. THEN BY WEDNESDAY...THE WEST
SOUTHWEST FLOW WILL INCREASE AHEAD OF AN APPROACHING STRONG CUT OFF
LOW DIVING DOWN SOUTHEAST INTO THE PAC NW WHICH WILL RESULT IN ISOLD
TO WIDELY SCATTERED SHOWERS IN THE NW MTNS AS THE FASTER MORE FALL
LIKE PROGRESSIVE FLOW PATTERN APPEARS TO BECOME ESTABLISHED FOR
NOW.

&&

.AVIATION.../00Z ISSUANCE/

SHOWERS AND ISOLATED THUNDERSTORMS WILL CONTINUE ACROSS MUCH OF
SWEETWATER...FREMONT AND NATRONA COUNTIES TODAY WITH
KLND...KRIW...KRKS AND KCPR MOST AFFECTED THROUGH ABOUT 03Z. SEE
TERMINAL FORECASTS FOR MORE DETAILS. A LESSER CHANCE OF SHOWERS AND
ISOLATED THUNDERSTORMS EXIST FURTHER WEST AND NORTH FROM THIS EAR.
AREAS OF MVFR TO LOCAL IFR WILL OCCUR DURING PERIODS OF HEAVIER
SHOWERS. AS SHOWERS END OR DECREASE TO ISOLATED SHOWERS LATER
TONIGHT...AREAS OF LOW CLOUDS AND FOG WILL DEVELOP OVER THE AREAS
THAT RECEIVED GOOD RAIN WITH LCL TO AREAS OF MVFR TO EVEN IFR
POTENTIALLY IMPACTING KRKS AND KCPR BETWEEN 06Z AND 15Z THURSDAY.

OVER THE NORTH VFR CONDITIONS WILL PREVAIL. ISOLATED SHOWERS AND
STORMS WILL OCCUR UNTIL 02Z...MAINLY OVER AND NEAR THE MOUNTAINS.

&&

.FIRE WEATHER...

AN AREA OF LOW PRESSURE MOVING ALONG THE WYOMING AND COLORADO BORDER
WILL KEEP SHOWERS AND ISOLATED THUNDERSTORMS INTO EARLY THIS EVENING.
MOST SHOWER ACTIVITY WILL IMPACT THE SERN HALF OF THE FORECAST
AREA...THOUGH SOME AREAS OF NORTHERN WYOMING WILL SEE THE
POTENTIAL FOR ISOLATED ACTIVITY THROUGH THE EARLY EVENING HOURS.
THURSDAY WILL BE WARMER AND DRIER BUT WITH NO SIGNIFICANT WINDS. A
WEAK SYSTEM WILL PASS ACROSS THE NORTH ON FRIDAY WITH ISOLATED
SHOWERS AND THUNDERSTORMS AND AREAS OF BREEZY TO LOCALLY WINDY
CONDITIONS.

&&

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

&&

$$

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









000
FXUS65 KRIW 272219 CCA
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
143 PM MDT WED AUG 27 2014

.SHORT TERM...TONIGHT AND THURSDAY

MID LEVEL CIRCULATION NEAR MUDDY GAP AT MIDDAY WITH UPPER
CIRCULATION OVER NERN UT MOVING INTO FAR NWRN CO. IMPRESSIVE VWP
SOUNDING TODAY WITH NE FLOW IN THE MID LEVELS AND SE UPPER FLOW.
BAROCLINIC SHIELD OF PCPN MOVED NWWD ALL THE WAY INTO LND AND THE
EDGE OF RIW WITH .14 INCHES OF RAIN IN LANDER BETWEEN 11 AND NOON
AND ANOTHER .05 BETWEEN NOON AND 1 PM. CAMP CREEK RAWS NEAR MUDDY
GAP REPORTED .83 INCHES OF RAIN THIS MORNING (0.85 NOW). EVEN
SOUTH PASS CITY WAS NEARING THREE QUARTERS OF AN INCH AS OF 1PM.
MANY AREAS OVER NERN SWEETWATER COUNTY...SERN/ERN FREMONT AND
WRN/NRN NATRONA HAVE ALSO LIKELY RECEIVED AROUND A HALF OF AN INCH
THIS MORNING WITH RAIN ONGOING. EVEN RIVERTON IS GETTING
MEASURABLE RAIN WITH 0.03 AS OF 130 PM TODAY. CIRCULATION WILL
WEAKEN AND OPEN UP LATER TODAY AND THEN MOVE OFF TO THE EAST
TONIGHT INTO THURSDAY MORNING. SHOWERS AND ISOLATED THUNDERSTORMS
WILL CONTINUE INTO THE EVENING WITH THE HIGHEST PROBABILITY
SHIFTING SEWD. SHORTWAVE RIDGING THEN MOVES IN FOR A DRY AND WARMER
THURSDAY. BL LOOKS MOIST LATE TONIGHT SO COULD DEFINITELY SEE LOW
CLOUDS AND OR FOG IN OUR SERN ZONES WHERE LIGHT WINDS AND RECENT
RAINFALL HELP OUT.

.LONG TERM...THURSDAY NIGHT THROUGH WEDNESDAY

THE TROUGH THAT IS GIVING SOUTHERN AND EAST CENTRAL WYOMING RAIN
TODAY WILL BE EXITING EAST ACROSS THE PLAINS BY THURSDAY NIGHT. THEN
A FAST MOVING SHORTWAVE WILL BE SCOOTING RAPIDLY EAST ACROSS MONTANA
FRIDAY. THE FLOW OVER WYOMING SOUTH OF THIS SHORTWAVE WILL BE
WESTERLY AND SLIGHTLY DIFLUENT. THE LIFT FROM THIS SHORTWAVE WILL
REMAIN TO THE NORTH IN MONTANA. HIGHER CAPES ARE PROGGED FOR JOHNSON
COUNTY FRIDAY ALONG WITH JUST SLIGHTLY NEGATIVE LIFTED INDICES.
MARGINAL AMOUNTS OF MOISTURE ARE PROGGED FOR FAR NORTHERN WY FRIDAY
WITH MOST OF THE 500-700MB MOISTURE REMAINING UP IN MONTANA. WENT
WITH JUST SCATTERED SHOWERS IN THE NORTHERN MTNS FOR FRIDAY AS WELL
AS IN THE WIND RIVER MOUNTAINS.

THE GFS HAS COME MORE IN LINE WITH THE ECMWF IN THAT IT IS BRINGING
A SHORTWAVE/COLD FRONT THROUGH OUR CWA SATURDAY AND ANOTHER ONE ON MONDAY
ALONG WITH THE ASCT LONG WAVE TROUGH TO PASS THROUGH SUNDAY. HAVE
KEPT WIDESPREAD/NUMEROUS SHOWERS AND A FEW THUNDERSTORMS ACROSS THE
AREA FOP SATURDAY ASCT WITH THE SHORTWAVE...ESP IN THE AFTERNOON AND
IN THE NORTHWEST. ELSEWHERE ON SATURDAY AHEAD OF THE COLD
FRONT...WARM...BREEZY AND DRY CONDITIONS ARE EXPECTED...ESPECIALLY
FROM RKS TO CPR...WHERE FIRE WEATHER CONCERNS WILL LIKELY BE SOMEWHAT
ELEVATED. IN FACT...SATURDAY APPEARS TO BE THE WARMEST DAY OF THE
WEEK WITH HIGHS IN THE 80S EXPECTED AT THE LOWER ELEVATIONS EAST OF
THE DIVIDE AND 70S WEST. H7 TEMPS BEHIND THIS TROUGH/COLD FRONT WILL
DROP TO NEAR ZERO IN NORTHERN WY BY SUNDAY WHICH WOULD BRING THE
SNOW LEVEL DOWN TO 8500 FEET IN THE NORTHERN MTNS. MAINLY SCATTERED
SHOWERS ARE EXPECTED FOR COVERAGE SUNDAY WITH THE LONG WAVE TROUGH.
SCATTERED SHOWER ACTIVITY IS STILL EXPECTED MONDAY WITH THE NEXT
SHORTWAVE. NOT MUCH IN THE WAY OF THUNDERSTORM ACTIVITY ANYWHERE IS
EXPECTED AFTER SATURDAY WITH THE STABILIZING AIR MASS...MAINLY JUST
SHOWERS. WITH A CONTINUED WESTERLY...SOMEWHAT MOIST PACIFIC
FLOW...STILL EXPECTING SOME ISOLATED SHOWERS IN THE HIGHEST FAR NW
MTNS TUESDAY. THIS WESTERLY FLOW WILL RESULT IN JUST DRY CONDITIONS
IN MOST AREAS OF THE CWA TUESDAY. THEN BY WEDNESDAY...THE WEST
SOUTHWEST FLOW WILL INCREASE AHEAD OF AN APPROACHING STRONG CUT OFF
LOW DIVING DOWN SOUTHEAST INTO THE PAC NW WHICH WILL RESULT IN ISOLD
TO WIDELY SCATTERED SHOWERS IN THE NW MTNS AS THE FASTER MORE FALL
LIKE PROGRESSIVE FLOW PATTERN APPEARS TO BECOME ESTABLISHED FOR
NOW.

&&

.AVIATION.../00Z ISSUANCE/

SHOWERS AND ISOLATED THUNDERSTORMS WILL CONTINUE ACROSS MUCH OF
SWEETWATER...FREMONT AND NATRONA COUNTIES TODAY WITH
KLND...KRIW...KRKS AND KCPR MOST AFFECTED THROUGH ABOUT 03Z. SEE
TERMINAL FORECASTS FOR MORE DETAILS. A LESSER CHANCE OF SHOWERS AND
ISOLATED THUNDERSTORMS EXIST FURTHER WEST AND NORTH FROM THIS EAR.
AREAS OF MVFR TO LOCAL IFR WILL OCCUR DURING PERIODS OF HEAVIER
SHOWERS. AS SHOWERS END OR DECREASE TO ISOLATED SHOWERS LATER
TONIGHT...AREAS OF LOW CLOUDS AND FOG WILL DEVELOP OVER THE AREAS
THAT RECEIVED GOOD RAIN WITH LCL TO AREAS OF MVFR TO EVEN IFR
POTENTIALLY IMPACTING KRKS AND KCPR BETWEEN 06Z AND 15Z THURSDAY.

OVER THE NORTH VFR CONDITIONS WILL PREVAIL. ISOLATED SHOWERS AND
STORMS WILL OCCUR UNTIL 02Z...MAINLY OVER AND NEAR THE MOUNTAINS.

&&

.FIRE WEATHER...

AN AREA OF LOW PRESSURE MOVING ALONG THE WYOMING AND COLORADO BORDER
WILL KEEP SHOWERS AND ISOLATED THUNDERSTORMS INTO EARLY THIS EVENING.
MOST SHOWER ACTIVITY WILL IMPACT THE SERN HALF OF THE FORECAST
AREA...THOUGH SOME AREAS OF NORTHERN WYOMING WILL SEE THE
POTENTIAL FOR ISOLATED ACTIVITY THROUGH THE EARLY EVENING HOURS.
THURSDAY WILL BE WARMER AND DRIER BUT WITH NO SIGNIFICANT WINDS. A
WEAK SYSTEM WILL PASS ACROSS THE NORTH ON FRIDAY WITH ISOLATED
SHOWERS AND THUNDERSTORMS AND AREAS OF BREEZY TO LOCALLY WINDY
CONDITIONS.

&&

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

&&

$$

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










000
FXUS65 KCYS 272213
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
413 PM MDT WED AUG 27 2014

.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 413 PM MDT WED AUG 27 2014

THE STRONG UPPER LOW IS MOVING INTO WESTERN COLORADO THIS
AFTERNOON AS SEEN ON WATER VAPOR IMAGERY. A POTENT SHORTWAVE
MOVED OUT AHEAD OF THE LOW AND OVER THE FORECAST AREA THIS
MORNING...SPARKING OFF NUMEROUS SHOWERS AND TSTORMS MAINLY ALONG
AND EAST OF THE LARAMIE RANGE. SOME TRAINING OF STORMS WAS OBSERVED
ALONG A SFC BOUNDARY THAT WAS SITUATED NEAR THE WY/NE BORDER
EARLIER...WITH MODERATE TO HEAVY RAIN OBSERVED WITH THE
THUNDERSTORM ACTIVITY. SOME MINOR TO MODERATE FLOODING OCCURRED
ACROSS CENTRAL GOSHEN COUNTY WITHIN THE AREA OF TRAINING STORMS.
THAT BOUNDARY HAS SINCE PUSHED OFF TO THE SOUTH AND EAST...LIKELY
WITH THE HELP OF THUNDERSTORM OUTFLOW AND AS SFC CYCLOGENESIS IS
OCCURRING IN SOUTHEAST COLORADO...ACCELERATING THE SOUTHWARD
MOVEMENT OF THE BOUNDARY. THE BULK OF THE THUNDERSTORM ACTIVITY IS
NOW OVER FAR NORTHERN AND EASTERN PORTIONS OF THE PANHANDLE THIS
AFTERNOON ON THE LEADING EDGE OF THE SHORTWAVE...WITH THE HEAVIEST
RAIN EXPECTED TO PUSH OFF TO THE EAST-NORTHEAST THROUGH THE
EVENING. ANOTHER ROUND OF SHOWERS AND STORMS ARE MOVING UP FROM
THE SOUTHWEST ON THE NOSE OF A JETLET ROUNDING THE BASE OF THE
TROUGH. THIS ACTIVITY IS OCCURRING WITHIN A DRIER AIRMASS PER
WATER VAPOR IMAGERY...SO RAIN RATES SHOULD BE LESS OVERALL.
INCREASING SOLAR INSOLATION OVER THE NEXT FEW HOURS COULD HELP
DESTABILIZE THE ATMOSPHERE SOMEWHAT ACROSS THE WYO PLAINS...SO
CANNOT RULE OUT THE IDEA THAT THESE STORMS MOVING OFF THE MOUNTAINS
COULD BECOME STRONG WITH THE HELP OF THE APPROACHING JET. HOWEVER THE
ATMOSPHERE IS FAIRLY WORKED OVER FROM EARLIER ACTIVITY SO NOT
WHOLLY CONFIDENT STORMS WILL INTENSIFY MUCH.

THE UPPER LOW WILL CONTINUE TO TREK SOUTHEAST INTO THE CENTRAL
PLAINS THROUGH THURSDAY...WITH WRAPAROUND ENERGY AND MOISTURE
MAINTAINING CHANCES FOR SHOWERS AND TSTORMS ACROSS THE CWA TONIGHT.
MIDLEVEL CONVERGENCE WITHIN THE TROUGH AXIS WILL MOVE OVERHEAD ON
THURSDAY...WITH THE ADDITION OF BROADSCALE LIFT WITHIN THE LEFT
ENTRANCE OF THE CURVED JET AIDING IN DEVELOPMENT OF CONVECTION
THROUGH THE DAY. THE MAIN FOCUS WILL BE SOUTH OF A RAWLINS-LUSK-
CHADRON LINE. MUCH DRIER AIR WILL FILTER IN FROM THE NORTHWEST AS
A SHORTWAVE RIDGE MOVES OVERHEAD THURSDAY NIGHT AND EARLY
FRIDAY...WITH A WEAK WAVE APPROACHING FROM THE NORTHWEST FRIDAY
AFTERNOON. A FEW WEAK TSTORMS ARE POSSIBLE IN THE AFTERNOON AS THE
WAVE APPROACHES.

.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 413 PM MDT WED AUG 27 2014

MEDIUM RANGE MODELS ARE IN EXCELLENT AGREEMENT WITH A BROAD MIDLVL
SHORTWAVE MOVING ACROSS THE PACIFIC NW EARLY IN THE PERIOD. SEASONAL
WARMTH WILL OCCUR IN ADVANCE OF THIS FEATURE WITH H7 TEMPS AROUND 10
TO 14 C PER THE GFS ON SAT. CONSIDERABLE 700-300 MILLIBAR MOISTURE
AND INCREASING QG ASCENT WITH THE APPROACHING WAVE WOULD SUGGEST AN
INCREASE IN SHOWER AND TSTM ACTIVITY...EVEN AT NON DIURNALLY FAVORED
TIMES OF DAY. DO NOT EXPECT A WASHOUT BY ANY MEANS...BUT THERE WILL
PROBABLY BE CONVECTION AROUND. LOOKING A BIT BREEZY EACH AFTN OVER
THE HOLIDAY WEEKEND...ESPECIALLY WEST OF THE LARAMIE RANGE WITH AN
INCREASE IN HEIGHT GRADIENTS ALOFT AND THE SFC LOW PASSING ACROSS
NORTHERN WY. COOLER ON SUN/MON AS THE UPPER-LEVEL SYSTEM MOVES
OVERHEAD. THE ECMWF SHOWS 1000-500 MILLIBAR THICKNESSES FALLING TO
AROUND 570 DM...AND MOS GUIDANCE SUGGESTS SFC TEMPS WILL BE A GOOD
10 TO 15 DEGREES COOLER WHEN COMPARED TO SAT. AN UNSETTLED WEATHER
PATTERN WILL PERSIST THRU EARLY NEXT WEEK WITH DISTURBANCES EMBEDDED
WITHIN QUASI-ZONAL FLOW. WEAK UPPER-LEVEL RIDGING SHOULD GIVE WAY TO
A GRADUAL WARMING TREND THROUGH MIDWEEK WITH LESSER CHANCES FOR PCPN
FROM TUE ONWARD.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY MORNING)
ISSUED AT 1130 AM MDT WED AUG 27 2014

SCATTERED TO NUMEROUS SHOWERS AND STORMS CAN BE EXPECTED ACROSS
SOUTHEAST WY AND THE WESTERN NE PANHANDLE TODAY. MOST TERMINALS
WILL SEE LOWER CIGS BETWEEN 5K AND 8K FEET AGL THROUGH THE TAF
PERIOD...WITH OCCASIONAL MVFR CONDITIONS WITH BKN-TO-OVC SKIES
AROUND 2K FEET. LOWEST CIGS/VSBYS WILL OCCUR BENEATH SHOWERS AND
STORMS. A FEW STRONGER STORMS ARE POSSIBLE THIS AFTN FOR THE NE
PANHANDLE SITES...WITH TORRENTIAL DOWNPOURS AND STRONG/VARIABLE
WINDS POSSIBLE ALONG WITH SMALL HAIL. SHOWER ACTIVITY IS LIKELY
TO PERSIST ACROSS MUCH OF THE REGION OVERNIGHT. WE CANNOT RULE
OUT MVFR CIGS LATE TONIGHT OR EARLY THU...ESPECIALLY IN AREAS
WHICH RECEIVE HEAVIER RAINFALL THIS AFTN.

&&

.FIRE WEATHER...
ISSUED AT 413 PM MDT WED AUG 27 2014

NUMEROUS SHOWERS AND SCATTERED THUNDERSTORMS WILL
CONTINUE OVER THE DISTRICT THIS AFTERNOON AND TONIGHT. THIS
ACTIVITY WILL PRODUCE MODERATE TO HEAVY RAIN AND PERHAPS SOME
SMALL HAIL AS WELL. A MORE ISOLATED COVERAGE FOR SHOWERS AND
T-STORMS IS EXPECTED FOR THURSDAY...WITH THE MAIN FOCUS FOR THIS
ACTIVITY IN THE MOUNTAINS AND NEAR THE COLORADO BORDER. DRIER AND
WARMER WEATHER WILL RETURN FRIDAY AND CONTINUE THIS
WEEKEND...ALONG WITH GUSTY WEST TO SOUTHWEST WINDS. THERE WILL BE
A SLIGHT CHANCE FOR SHOWERS AND THUNDERSTORMS LATE SUNDAY AND LABOR
DAY WITH THE PASSAGE OF A UPPER LEVEL TROUGH AND PACIFIC COLD
FRONT.

&&

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

$$

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






000
FXUS65 KCYS 272213
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
413 PM MDT WED AUG 27 2014

.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 413 PM MDT WED AUG 27 2014

THE STRONG UPPER LOW IS MOVING INTO WESTERN COLORADO THIS
AFTERNOON AS SEEN ON WATER VAPOR IMAGERY. A POTENT SHORTWAVE
MOVED OUT AHEAD OF THE LOW AND OVER THE FORECAST AREA THIS
MORNING...SPARKING OFF NUMEROUS SHOWERS AND TSTORMS MAINLY ALONG
AND EAST OF THE LARAMIE RANGE. SOME TRAINING OF STORMS WAS OBSERVED
ALONG A SFC BOUNDARY THAT WAS SITUATED NEAR THE WY/NE BORDER
EARLIER...WITH MODERATE TO HEAVY RAIN OBSERVED WITH THE
THUNDERSTORM ACTIVITY. SOME MINOR TO MODERATE FLOODING OCCURRED
ACROSS CENTRAL GOSHEN COUNTY WITHIN THE AREA OF TRAINING STORMS.
THAT BOUNDARY HAS SINCE PUSHED OFF TO THE SOUTH AND EAST...LIKELY
WITH THE HELP OF THUNDERSTORM OUTFLOW AND AS SFC CYCLOGENESIS IS
OCCURRING IN SOUTHEAST COLORADO...ACCELERATING THE SOUTHWARD
MOVEMENT OF THE BOUNDARY. THE BULK OF THE THUNDERSTORM ACTIVITY IS
NOW OVER FAR NORTHERN AND EASTERN PORTIONS OF THE PANHANDLE THIS
AFTERNOON ON THE LEADING EDGE OF THE SHORTWAVE...WITH THE HEAVIEST
RAIN EXPECTED TO PUSH OFF TO THE EAST-NORTHEAST THROUGH THE
EVENING. ANOTHER ROUND OF SHOWERS AND STORMS ARE MOVING UP FROM
THE SOUTHWEST ON THE NOSE OF A JETLET ROUNDING THE BASE OF THE
TROUGH. THIS ACTIVITY IS OCCURRING WITHIN A DRIER AIRMASS PER
WATER VAPOR IMAGERY...SO RAIN RATES SHOULD BE LESS OVERALL.
INCREASING SOLAR INSOLATION OVER THE NEXT FEW HOURS COULD HELP
DESTABILIZE THE ATMOSPHERE SOMEWHAT ACROSS THE WYO PLAINS...SO
CANNOT RULE OUT THE IDEA THAT THESE STORMS MOVING OFF THE MOUNTAINS
COULD BECOME STRONG WITH THE HELP OF THE APPROACHING JET. HOWEVER THE
ATMOSPHERE IS FAIRLY WORKED OVER FROM EARLIER ACTIVITY SO NOT
WHOLLY CONFIDENT STORMS WILL INTENSIFY MUCH.

THE UPPER LOW WILL CONTINUE TO TREK SOUTHEAST INTO THE CENTRAL
PLAINS THROUGH THURSDAY...WITH WRAPAROUND ENERGY AND MOISTURE
MAINTAINING CHANCES FOR SHOWERS AND TSTORMS ACROSS THE CWA TONIGHT.
MIDLEVEL CONVERGENCE WITHIN THE TROUGH AXIS WILL MOVE OVERHEAD ON
THURSDAY...WITH THE ADDITION OF BROADSCALE LIFT WITHIN THE LEFT
ENTRANCE OF THE CURVED JET AIDING IN DEVELOPMENT OF CONVECTION
THROUGH THE DAY. THE MAIN FOCUS WILL BE SOUTH OF A RAWLINS-LUSK-
CHADRON LINE. MUCH DRIER AIR WILL FILTER IN FROM THE NORTHWEST AS
A SHORTWAVE RIDGE MOVES OVERHEAD THURSDAY NIGHT AND EARLY
FRIDAY...WITH A WEAK WAVE APPROACHING FROM THE NORTHWEST FRIDAY
AFTERNOON. A FEW WEAK TSTORMS ARE POSSIBLE IN THE AFTERNOON AS THE
WAVE APPROACHES.

.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 413 PM MDT WED AUG 27 2014

MEDIUM RANGE MODELS ARE IN EXCELLENT AGREEMENT WITH A BROAD MIDLVL
SHORTWAVE MOVING ACROSS THE PACIFIC NW EARLY IN THE PERIOD. SEASONAL
WARMTH WILL OCCUR IN ADVANCE OF THIS FEATURE WITH H7 TEMPS AROUND 10
TO 14 C PER THE GFS ON SAT. CONSIDERABLE 700-300 MILLIBAR MOISTURE
AND INCREASING QG ASCENT WITH THE APPROACHING WAVE WOULD SUGGEST AN
INCREASE IN SHOWER AND TSTM ACTIVITY...EVEN AT NON DIURNALLY FAVORED
TIMES OF DAY. DO NOT EXPECT A WASHOUT BY ANY MEANS...BUT THERE WILL
PROBABLY BE CONVECTION AROUND. LOOKING A BIT BREEZY EACH AFTN OVER
THE HOLIDAY WEEKEND...ESPECIALLY WEST OF THE LARAMIE RANGE WITH AN
INCREASE IN HEIGHT GRADIENTS ALOFT AND THE SFC LOW PASSING ACROSS
NORTHERN WY. COOLER ON SUN/MON AS THE UPPER-LEVEL SYSTEM MOVES
OVERHEAD. THE ECMWF SHOWS 1000-500 MILLIBAR THICKNESSES FALLING TO
AROUND 570 DM...AND MOS GUIDANCE SUGGESTS SFC TEMPS WILL BE A GOOD
10 TO 15 DEGREES COOLER WHEN COMPARED TO SAT. AN UNSETTLED WEATHER
PATTERN WILL PERSIST THRU EARLY NEXT WEEK WITH DISTURBANCES EMBEDDED
WITHIN QUASI-ZONAL FLOW. WEAK UPPER-LEVEL RIDGING SHOULD GIVE WAY TO
A GRADUAL WARMING TREND THROUGH MIDWEEK WITH LESSER CHANCES FOR PCPN
FROM TUE ONWARD.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY MORNING)
ISSUED AT 1130 AM MDT WED AUG 27 2014

SCATTERED TO NUMEROUS SHOWERS AND STORMS CAN BE EXPECTED ACROSS
SOUTHEAST WY AND THE WESTERN NE PANHANDLE TODAY. MOST TERMINALS
WILL SEE LOWER CIGS BETWEEN 5K AND 8K FEET AGL THROUGH THE TAF
PERIOD...WITH OCCASIONAL MVFR CONDITIONS WITH BKN-TO-OVC SKIES
AROUND 2K FEET. LOWEST CIGS/VSBYS WILL OCCUR BENEATH SHOWERS AND
STORMS. A FEW STRONGER STORMS ARE POSSIBLE THIS AFTN FOR THE NE
PANHANDLE SITES...WITH TORRENTIAL DOWNPOURS AND STRONG/VARIABLE
WINDS POSSIBLE ALONG WITH SMALL HAIL. SHOWER ACTIVITY IS LIKELY
TO PERSIST ACROSS MUCH OF THE REGION OVERNIGHT. WE CANNOT RULE
OUT MVFR CIGS LATE TONIGHT OR EARLY THU...ESPECIALLY IN AREAS
WHICH RECEIVE HEAVIER RAINFALL THIS AFTN.

&&

.FIRE WEATHER...
ISSUED AT 413 PM MDT WED AUG 27 2014

NUMEROUS SHOWERS AND SCATTERED THUNDERSTORMS WILL
CONTINUE OVER THE DISTRICT THIS AFTERNOON AND TONIGHT. THIS
ACTIVITY WILL PRODUCE MODERATE TO HEAVY RAIN AND PERHAPS SOME
SMALL HAIL AS WELL. A MORE ISOLATED COVERAGE FOR SHOWERS AND
T-STORMS IS EXPECTED FOR THURSDAY...WITH THE MAIN FOCUS FOR THIS
ACTIVITY IN THE MOUNTAINS AND NEAR THE COLORADO BORDER. DRIER AND
WARMER WEATHER WILL RETURN FRIDAY AND CONTINUE THIS
WEEKEND...ALONG WITH GUSTY WEST TO SOUTHWEST WINDS. THERE WILL BE
A SLIGHT CHANCE FOR SHOWERS AND THUNDERSTORMS LATE SUNDAY AND LABOR
DAY WITH THE PASSAGE OF A UPPER LEVEL TROUGH AND PACIFIC COLD
FRONT.

&&

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

$$

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







000
FXUS63 KUNR 272105
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
305 PM MDT WED AUG 27 2014

.SHORT TERM...THIS EVENING THROUGH THURSDAY NIGHT
ISSUED AT 305 PM MDT WED AUG 27 2014

CURRENT SURFACE ANALYSIS SHOWS LOW PRESSURE OVER FAR NORTHEAST
CO...WITH A NEARLY STATIONARY FRONTAL BOUNDARY FROM SOUTHERN WY TO
CENTRAL KS. UPPER LEVEL ANALYSIS SHOWS LOW PRESSURE OVER NORTHWEST
CO...WITH TROF COVERING THE ROCKIES AND MUCH OF THE HIGH PLAINS.
SKIES HAVE BECOME MOSTLY CLOUDY ACROSS MUCH OF THE AREA...EXCEPT
FOR FAR NORTHWESTERN SD. REGIONAL RADARS SHOW MAIN BAND OF SHOWERS
AND STORMS ROTATING NORTH-NORTHEAST AROUND UPPER LOW ACROSS MUCH
OF EASTERN WY...THE NEB PANHANDLE...AND INTO FAR SOUTHWESTERN SD.
SCATTERED SHOWERS AND STORMS HAVE DEVELOPED ELSEWHERE ACROSS
SOUTHWEST AND SOUTH CENTRAL SD...AS WELL AS OVER THE BLACK HILLS.
SLOW MOVING STORMS OVER WESTERN PORTIONS OF THE BLACK HILLS HAVE
PRODUCED SOME LOCALLY HEAVY RAINFALL EARLY THIS AFTERNOON.
TEMPERATURES ARE IN THE UPPER 60S AND 70S WITH SOUTHEASTERLY
WINDS.

THE GENERAL TREND FOR SCATTERED TO NUMEROUS SHOWERS AND
THUNDERSTORMS SHOULD CONTINUE INTO TONIGHT ACROSS SOUTHERN PORTIONS
OF THE CWA AS THE UPPER LOW MOVES SLOWLY EAST INTO THE CENTRAL HIGH
PLAINS BY EARLY THURSDAY. THERE WILL BE A FAIRLY SHARP CUT-OFF TO
THE COVERAGE OF SHOWERS THROUGH THE EVENING...GENERALLY SOUTH OF
INTERSTATE 90. THE THREAT FOR SEVERE STORMS REMAINS LOW WITH MAIN
AREA OF INSTABILITY STAYING SOUTH OF THE FORECAST AREA AND WEAK
SHEAR IN PLACE. HOWEVER...THERE IS A THREAT FOR LOCALLY HEAVY
RAINFALL ACROSS SOUTHERN AREAS THIS EVENING...ESPECIALLY OVER FAR
SOUTHWEST INTO SOUTH CENTRAL SD...WHERE PRECIPITABLE WATER VALUES
WILL BE WELL ABOVE AVERAGE AND A COMPLEX OF STORMS COULD MOVE
THROUGH DURING THE EVENING. WITH A LOT OF LOW LEVEL MOISTURE AROUND
THE AREA AND LIGHT WINDS OVERNIGHT...WILL ADD AREAS OF FOG TO MUCH
OF THE WESTERN AND SOUTH CENTRAL SD PLAINS LATE TONIGHT INTO EARLY
THURSDAY.

AS THE UPPER LOW MOVES SLOWLY ACROSS THE CENTRAL HIGH PLAINS LATE
TONIGHT AND THURSDAY...CHANCES FOR SHOWERS AND STORMS SHOULD MOSTLY
BE LIMITED TO THE SOUTH CENTRAL SD AREA. WILL ADD A SLIGHT CHANCE
FOR SHOWERS AND STORMS TO THE CENTRAL AND SOUTHERN BLACK HILLS FOR
THE AFTERNOON WITH SOME LINGERING INSTABILITY AROUND POSSIBLY
PRODUCING A TERRAIN INDUCED SHOWER OR STORM. SKIES WILL BE VARIABLY
CLOUDY...WITH THE MOST SUN ACROSS NORTHERN AND WESTERN PORTIONS OF
THE CWA. WARMER AIR CAN BE EXPECTED ON THURSDAY...ESPECIALLY
ACROSS THESE NORTHERN AND WESTERN AREAS. HIGHS SHOULD RANGE FROM THE
MID 70S TO MID 80S.

CLOUDS WILL CONTINUE TO GRADUALLY DECREASE FROM NORTHWEST TO
SOUTHEAST LATE THURSDAY INTO THURSDAY NIGHT...WITH MOSTLY CLEAR
SKIES OVERNIGHT. SOME FOG COULD AGAIN BE POSSIBLE OVER THE SD PLAINS
LATE...BUT WILL TAKE A CLOSER LOOK AT THAT TOMORROW. LOWS WILL BE IN
THE 50S AND LOWER 60S WITH MOSTLY LIGHT AND VARIABLE WINDS.

&&

.LONG TERM...FRIDAY THROUGH WEDNESDAY
ISSUED AT 305 PM MDT WED AUG 27 2014

FRIDAY...A SHORTWAVE WILL MOVE ACROSS MT/ND PUSHING A COLD FRONT
SOUTH OF THE CWA AS HIGH PRESSURE BUILDS IN OVER SOUTH CENTRAL
CANADA. DEPENDING ON THE AMOUNT OF LOW LEVEL SUBSIDENCE BEHIND THE
SHORTWAVE...A NARROW BAND OF SUFFICIENT CAPE/SHEAR PRESENT FOR
POST FRONTAL ISOLATED STRONG/SEVERE STORMS ACROSS NORTHWEST HALF
OF CWA...BUT CONFIDENCE LOW. TEMPERATURES WILL BE TRICKY WITH WEAK
COOL AIR ADVECTION.

SATURDAY...ANOTHER SHORTWAVE WILL MOVE ACROSS SOUTHERN MT/NORTHERN
WY AHEAD OF LEE TROUGH...WHICH WILL DEVELOP A LOW ALONG IT IN
SOUTHEAST MT AND DRAG ANOTHER COLD FRONT THROUGH THE CWA SATURDAY
NIGHT. SUFFICIENT CAPE/SHEAR WILL BE PRESENT FOR STRONG/SEVERE
STORMS...BUT MLCIN MAY BE NOTABLE GIVEN DEVELOPING THERMAL RIDGE
AHEAD OF SHORTWAVE. TEMPERATURES WILL BE NEAR NORMAL.

HAVE ADDED/EXPANDED POPS BOTH FRIDAY/SATURDAY TO ACCOUNT FOR LATEST
THINKING.

SUNDAY THROUGH WEDNESDAY...ACTIVE PATTERN CONTINUES WITH NORTHWEST
FLOW ALOFT SUNDAY THROUGH TUESDAY...WITH A SLOW TRANSITION TO
RIDGING ACROSS THE NORTHERN PLAINS FOR THE MIDDLE OF THE WEEK.
COOLISH TEMPERATURES TO START SUNDAY BEHIND SATURDAY/S COOL
FRONT...BUT THEN WARMING BACK TO NEAR NORMAL FOR THE MIDDLE OF NEXT
WEEK.

&&

.AVIATION...FOR THE 18Z TAFS THROUGH 18Z THURSDAY
ISSUED AT 305 PM MDT WED AUG 27 2014

SCATTERED SHRA/TSRA EXPECTED ACROSS SOUTHERN HALF OF AREA THROUGH
TONIGHT. LOCAL MVFR CIGS/VSBYS EXPECTED WITH THE HEAVIER
PRECIPITATION. AREAS ST/BR ALSO EXPECTED THROUGH THE PERIOD
ALONG/SOUTH OF A LINE FROM KPHP TO KCUT...ALTHOUGH FINAL NORTHERN
EDGE OF ST/BR WILL BE LARGELY DEPENDENT ON HOW FAR NORTH
PRECIPITATION DEVELOPS. NORTHERN HALF OF CWA SHOULD REMAIN LARGELY
VFR THROUGH THE PERIOD...ALTHOUGH AREAS MVFR VSBYS DUE TO BR ARE
POSSIBLE LATE TONIGHT ON THE SD PLAINS AS SURFACE T/TD SPREADS
CONVERGE.

&&

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

$$

SHORT TERM...26
LONG TERM...HELGESON
AVIATION...HELGESON






000
FXUS63 KUNR 272105
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
305 PM MDT WED AUG 27 2014

.SHORT TERM...THIS EVENING THROUGH THURSDAY NIGHT
ISSUED AT 305 PM MDT WED AUG 27 2014

CURRENT SURFACE ANALYSIS SHOWS LOW PRESSURE OVER FAR NORTHEAST
CO...WITH A NEARLY STATIONARY FRONTAL BOUNDARY FROM SOUTHERN WY TO
CENTRAL KS. UPPER LEVEL ANALYSIS SHOWS LOW PRESSURE OVER NORTHWEST
CO...WITH TROF COVERING THE ROCKIES AND MUCH OF THE HIGH PLAINS.
SKIES HAVE BECOME MOSTLY CLOUDY ACROSS MUCH OF THE AREA...EXCEPT
FOR FAR NORTHWESTERN SD. REGIONAL RADARS SHOW MAIN BAND OF SHOWERS
AND STORMS ROTATING NORTH-NORTHEAST AROUND UPPER LOW ACROSS MUCH
OF EASTERN WY...THE NEB PANHANDLE...AND INTO FAR SOUTHWESTERN SD.
SCATTERED SHOWERS AND STORMS HAVE DEVELOPED ELSEWHERE ACROSS
SOUTHWEST AND SOUTH CENTRAL SD...AS WELL AS OVER THE BLACK HILLS.
SLOW MOVING STORMS OVER WESTERN PORTIONS OF THE BLACK HILLS HAVE
PRODUCED SOME LOCALLY HEAVY RAINFALL EARLY THIS AFTERNOON.
TEMPERATURES ARE IN THE UPPER 60S AND 70S WITH SOUTHEASTERLY
WINDS.

THE GENERAL TREND FOR SCATTERED TO NUMEROUS SHOWERS AND
THUNDERSTORMS SHOULD CONTINUE INTO TONIGHT ACROSS SOUTHERN PORTIONS
OF THE CWA AS THE UPPER LOW MOVES SLOWLY EAST INTO THE CENTRAL HIGH
PLAINS BY EARLY THURSDAY. THERE WILL BE A FAIRLY SHARP CUT-OFF TO
THE COVERAGE OF SHOWERS THROUGH THE EVENING...GENERALLY SOUTH OF
INTERSTATE 90. THE THREAT FOR SEVERE STORMS REMAINS LOW WITH MAIN
AREA OF INSTABILITY STAYING SOUTH OF THE FORECAST AREA AND WEAK
SHEAR IN PLACE. HOWEVER...THERE IS A THREAT FOR LOCALLY HEAVY
RAINFALL ACROSS SOUTHERN AREAS THIS EVENING...ESPECIALLY OVER FAR
SOUTHWEST INTO SOUTH CENTRAL SD...WHERE PRECIPITABLE WATER VALUES
WILL BE WELL ABOVE AVERAGE AND A COMPLEX OF STORMS COULD MOVE
THROUGH DURING THE EVENING. WITH A LOT OF LOW LEVEL MOISTURE AROUND
THE AREA AND LIGHT WINDS OVERNIGHT...WILL ADD AREAS OF FOG TO MUCH
OF THE WESTERN AND SOUTH CENTRAL SD PLAINS LATE TONIGHT INTO EARLY
THURSDAY.

AS THE UPPER LOW MOVES SLOWLY ACROSS THE CENTRAL HIGH PLAINS LATE
TONIGHT AND THURSDAY...CHANCES FOR SHOWERS AND STORMS SHOULD MOSTLY
BE LIMITED TO THE SOUTH CENTRAL SD AREA. WILL ADD A SLIGHT CHANCE
FOR SHOWERS AND STORMS TO THE CENTRAL AND SOUTHERN BLACK HILLS FOR
THE AFTERNOON WITH SOME LINGERING INSTABILITY AROUND POSSIBLY
PRODUCING A TERRAIN INDUCED SHOWER OR STORM. SKIES WILL BE VARIABLY
CLOUDY...WITH THE MOST SUN ACROSS NORTHERN AND WESTERN PORTIONS OF
THE CWA. WARMER AIR CAN BE EXPECTED ON THURSDAY...ESPECIALLY
ACROSS THESE NORTHERN AND WESTERN AREAS. HIGHS SHOULD RANGE FROM THE
MID 70S TO MID 80S.

CLOUDS WILL CONTINUE TO GRADUALLY DECREASE FROM NORTHWEST TO
SOUTHEAST LATE THURSDAY INTO THURSDAY NIGHT...WITH MOSTLY CLEAR
SKIES OVERNIGHT. SOME FOG COULD AGAIN BE POSSIBLE OVER THE SD PLAINS
LATE...BUT WILL TAKE A CLOSER LOOK AT THAT TOMORROW. LOWS WILL BE IN
THE 50S AND LOWER 60S WITH MOSTLY LIGHT AND VARIABLE WINDS.

&&

.LONG TERM...FRIDAY THROUGH WEDNESDAY
ISSUED AT 305 PM MDT WED AUG 27 2014

FRIDAY...A SHORTWAVE WILL MOVE ACROSS MT/ND PUSHING A COLD FRONT
SOUTH OF THE CWA AS HIGH PRESSURE BUILDS IN OVER SOUTH CENTRAL
CANADA. DEPENDING ON THE AMOUNT OF LOW LEVEL SUBSIDENCE BEHIND THE
SHORTWAVE...A NARROW BAND OF SUFFICIENT CAPE/SHEAR PRESENT FOR
POST FRONTAL ISOLATED STRONG/SEVERE STORMS ACROSS NORTHWEST HALF
OF CWA...BUT CONFIDENCE LOW. TEMPERATURES WILL BE TRICKY WITH WEAK
COOL AIR ADVECTION.

SATURDAY...ANOTHER SHORTWAVE WILL MOVE ACROSS SOUTHERN MT/NORTHERN
WY AHEAD OF LEE TROUGH...WHICH WILL DEVELOP A LOW ALONG IT IN
SOUTHEAST MT AND DRAG ANOTHER COLD FRONT THROUGH THE CWA SATURDAY
NIGHT. SUFFICIENT CAPE/SHEAR WILL BE PRESENT FOR STRONG/SEVERE
STORMS...BUT MLCIN MAY BE NOTABLE GIVEN DEVELOPING THERMAL RIDGE
AHEAD OF SHORTWAVE. TEMPERATURES WILL BE NEAR NORMAL.

HAVE ADDED/EXPANDED POPS BOTH FRIDAY/SATURDAY TO ACCOUNT FOR LATEST
THINKING.

SUNDAY THROUGH WEDNESDAY...ACTIVE PATTERN CONTINUES WITH NORTHWEST
FLOW ALOFT SUNDAY THROUGH TUESDAY...WITH A SLOW TRANSITION TO
RIDGING ACROSS THE NORTHERN PLAINS FOR THE MIDDLE OF THE WEEK.
COOLISH TEMPERATURES TO START SUNDAY BEHIND SATURDAY/S COOL
FRONT...BUT THEN WARMING BACK TO NEAR NORMAL FOR THE MIDDLE OF NEXT
WEEK.

&&

.AVIATION...FOR THE 18Z TAFS THROUGH 18Z THURSDAY
ISSUED AT 305 PM MDT WED AUG 27 2014

SCATTERED SHRA/TSRA EXPECTED ACROSS SOUTHERN HALF OF AREA THROUGH
TONIGHT. LOCAL MVFR CIGS/VSBYS EXPECTED WITH THE HEAVIER
PRECIPITATION. AREAS ST/BR ALSO EXPECTED THROUGH THE PERIOD
ALONG/SOUTH OF A LINE FROM KPHP TO KCUT...ALTHOUGH FINAL NORTHERN
EDGE OF ST/BR WILL BE LARGELY DEPENDENT ON HOW FAR NORTH
PRECIPITATION DEVELOPS. NORTHERN HALF OF CWA SHOULD REMAIN LARGELY
VFR THROUGH THE PERIOD...ALTHOUGH AREAS MVFR VSBYS DUE TO BR ARE
POSSIBLE LATE TONIGHT ON THE SD PLAINS AS SURFACE T/TD SPREADS
CONVERGE.

&&

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

$$

SHORT TERM...26
LONG TERM...HELGESON
AVIATION...HELGESON







000
FXUS65 KRIW 271943
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
143 PM MDT WED AUG 27 2014

.SHORT TERM...TONIGHT AND THURSDAY

MID LEVEL CIRCULATION NEAR MUDDY GAP AT MIDDAY WITH UPPER
CIRCULATION OVER NERN UT MOVING INTO FAR NWRN CO. IMPRESSIVE VWP
SOUNDING TODAY WITH NE FLOW IN THE MID LEVELS AND SE UPPER FLOW.
BAROCLINIC SHIELD OF PCPN MOVED NWWD ALL THE WAY INTO LND AND THE
EDGE OF RIW WITH .14 INCHES OF RAIN IN LANDER BETWEEN 11 AND NOON
AND ANOTHER .05 BETWEEN NOON AND 1 PM. CAMP CREEK RAWS NEAR MUDDY
GAP REPORTED .83 INCHES OF RAIN THIS MORNING (0.85 NOW). EVEN
SOUTH PASS CITY WAS NEARING THREE QUARTERS OF AN INCH AS OF 1PM.
MANY AREAS OVER NERN SWEETWATER COUNTY...SERN/ERN FREMONT AND
WRN/NRN NATRONA HAVE ALSO LIKELY RECEIVED AROUND A HALF OF AN INCH
THIS MORNING WITH RAIN ONGOING. EVEN RIVERTON IS GETTING
MEASURABLE RAIN WITH 0.03 AS OF 130 PM TODAY. CIRCULATION WILL
WEAKEN AND OPEN UP LATER TODAY AND THEN MOVE OFF TO THE EAST
TONIGHT INTO THURSDAY MORNING. SHOWERS AND ISOLATED THUNDERSTORMS
WILL CONTINUE INTO THE EVENING WITH THE HIGHEST PROBABILITY
SHIFTING SEWD. SHORTWAVE RIDING THEN MOVES IN FOR A DRY AND WARMER
THURSDAY. BL LOOKS MOIST LATE TONIGHT SO COULD DEFINITELY SEE LOW
CLOUDS AND OR FOG IN OUR SERN ZONES WHERE LIGHT WINDS AND RECENT
RAINFALL HELP OUT.

.LONG TERM...THURSDAY NIGHT THROUGH WEDNESDAY

THE TROUGH THAT IS GIVING SOUTHERN AND EAST CENTRAL WYOMING RAIN
TODAY WILL BE EXITING EAST ACROSS THE PLAINS BY THURSDAY NIGHT. THEN
A FAST MOVING SHORTWAVE WILL BE SCOOTING RAPIDLY EAST ACROSS MONTANA
FRIDAY. THE FLOW OVER WYOMING SOUTH OF THIS SHORTWAVE WILL BE
WESTERLY AND SLIGHTLY DIFLUENT. THE LIFT FROM THIS SHORTWAVE WILL
REMAIN TO THE NORTH IN MONTANA. HIGHER CAPES ARE PROGGED FOR JOHNSON
COUNTY FRIDAY ALONG WITH JUST SLIGHTLY NEGATIVE LIFTED INDICES.
MARGINAL AMOUNTS OF MOISTURE ARE PROGGED FOR FAR NORTHERN WY FRIDAY
WITH MOST OF THE 500-700MB MOISTURE REMAINING UP IN MONTANA. WENT
WITH JUST SCATTERED SHOWERS IN THE NORTHERN MTNS FOR FRIDAY AS WELL
AS IN THE WIND RIVER MOUNTAINS.

THE GFS HAS COME MORE IN LINE WITH THE ECMWF IN THAT IT IS BRINGING
A SHORTWAVE/COLD FRONT THROUGH OUR CWA SATURDAY AND ANOTHER ONE ON MONDAY
ALONG WITH THE ASCT LONG WAVE TROUGH TO PASS THROUGH SUNDAY. HAVE
KEPT WIDESPREAD/NUMEROUS SHOWERS AND A FEW THUNDERSTORMS ACROSS THE
AREA FOP SATURDAY ASCT WITH THE SHORTWAVE...ESP IN THE AFTERNOON AND
IN THE NORTHWEST. ELSEWHERE ON SATURDAY AHEAD OF THE COLD
FRONT...WARM...BREEZY AND DRY CONDITIONS ARE EXPECTED...ESPECIALLY
FROM RKS TO CPR...WHERE FIRE WEATHER CONCERNS WILL LIKELY BE SOMEWHAT
ELEVATED. IN FACT...SATURDAY APPEARS TO BE THE WARMEST DAY OF THE
WEEK WITH HIGHS IN THE 80S EXPECTED AT THE LOWER ELEVATIONS EAST OF
THE DIVIDE AND 70S WEST. H7 TEMPS BEHIND THIS TROUGH/COLD FRONT WILL
DROP TO NEAR ZERO IN NORTHERN WY BY SUNDAY WHICH WOULD BRING THE
SNOW LEVEL DOWN TO 8500 FEET IN THE NORTHERN MTNS. MAINLY SCATTERED
SHOWERS ARE EXPECTED FOR COVERAGE SUNDAY WITH THE LONG WAVE TROUGH.
SCATTERED SHOWER ACTIVITY IS STILL EXPECTED MONDAY WITH THE NEXT
SHORTWAVE. NOT MUCH IN THE WAY OF THUNDERSTORM ACTIVITY ANYWHERE IS
EXPECTED AFTER SATURDAY WITH THE STABILIZING AIR MASS...MAINLY JUST
SHOWERS. WITH A CONTINUED WESTERLY...SOMEWHAT MOIST PACIFIC
FLOW...STILL EXPECTING SOME ISOLATED SHOWERS IN THE HIGHEST FAR NW
MTNS TUESDAY. THIS WESTERLY FLOW WILL RESULT IN JUST DRY CONDITIONS
IN MOST AREAS OF THE CWA TUESDAY. THEN BY WEDNESDAY...THE WEST
SOUTHWEST FLOW WILL INCREASE AHEAD OF AN APPROACHING STRONG CUT OFF
LOW DIVING DOWN SOUTHEAST INTO THE PAC NW WHICH WILL RESULT IN ISOLD
TO WIDELY SCATTERED SHOWERS IN THE NW MTNS AS THE FASTER MORE FALL
LIKE PROGRESSIVE FLOW PATTERN APPEARS TO BECOME ESTABLISHED FOR
NOW.

&&

.AVIATION.../00Z ISSUANCE/

SHOWERS AND ISOLATED THUNDERSTORMS WILL CONTINUE ACROSS MUCH OF
SWEETWATER...FREMONT AND NATRONA COUNTIES TODAY WITH
KLND...KRIW...KRKS AND KCPR MOST AFFECTED THROUGH ABOUT 03Z. SEE
TERMINAL FORECASTS FOR MORE DETAILS. A LESSER CHANCE OF SHOWERS AND
ISOLATED THUNDERSTORMS EXIST FURTHER WEST AND NORTH FROM THIS EAR.
AREAS OF MVFR TO LOCAL IFR WILL OCCUR DURING PERIODS OF HEAVIER
SHOWERS. AS SHOWERS END OR DECREASE TO ISOLATED SHOWERS LATER
TONIGHT...AREAS OF LOW CLOUDS AND FOG WILL DEVELOP OVER THE AREAS
THAT RECEIVED GOOD RAIN WITH LCL TO AREAS OF MVFR TO EVEN IFR
POTENTIALLY IMPACTING KRKS AND KCPR BETWEEN 06Z AND 15Z THURSDAY.

OVER THE NORTH VFR CONDITIONS WILL PREVAIL. ISOLATED SHOWERS AND
STORMS WILL OCCUR UNTIL 02Z...MAINLY OVER AND NEAR THE MOUNTAINS.

&&

.FIRE WEATHER...

AN AREA OF LOW PRESSURE MOVING ALONG THE WYOMING AND COLORADO BORDER
WILL KEEP SHOWERS AND ISOLATED THUNDERSTORMS INTO EARLY THIS EVENING.
MOST SHOWER ACTIVITY WILL IMPACT THE SERN HALF OF THE FORECAST
AREA...THOUGH SOME AREAS OF NORTHERN WYOMING WILL SEE THE
POTENTIAL FOR ISOLATED ACTIVITY THROUGH THE EARLY EVENING HOURS.
THURSDAY WILL BE WARMER AND DRIER BUT WITH NO SIGNIFICANT WINDS. A
WEAK SYSTEM WILL PASS ACROSS THE NORTH ON FRIDAY WITH ISOLATED
SHOWERS AND THUNDERSTORMS AND AREAS OF BREEZY TO LOCALLY WINDY
CONDITIONS.

&&

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

&&

$$

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







000
FXUS65 KRIW 271943
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
143 PM MDT WED AUG 27 2014

.SHORT TERM...TONIGHT AND THURSDAY

MID LEVEL CIRCULATION NEAR MUDDY GAP AT MIDDAY WITH UPPER
CIRCULATION OVER NERN UT MOVING INTO FAR NWRN CO. IMPRESSIVE VWP
SOUNDING TODAY WITH NE FLOW IN THE MID LEVELS AND SE UPPER FLOW.
BAROCLINIC SHIELD OF PCPN MOVED NWWD ALL THE WAY INTO LND AND THE
EDGE OF RIW WITH .14 INCHES OF RAIN IN LANDER BETWEEN 11 AND NOON
AND ANOTHER .05 BETWEEN NOON AND 1 PM. CAMP CREEK RAWS NEAR MUDDY
GAP REPORTED .83 INCHES OF RAIN THIS MORNING (0.85 NOW). EVEN
SOUTH PASS CITY WAS NEARING THREE QUARTERS OF AN INCH AS OF 1PM.
MANY AREAS OVER NERN SWEETWATER COUNTY...SERN/ERN FREMONT AND
WRN/NRN NATRONA HAVE ALSO LIKELY RECEIVED AROUND A HALF OF AN INCH
THIS MORNING WITH RAIN ONGOING. EVEN RIVERTON IS GETTING
MEASURABLE RAIN WITH 0.03 AS OF 130 PM TODAY. CIRCULATION WILL
WEAKEN AND OPEN UP LATER TODAY AND THEN MOVE OFF TO THE EAST
TONIGHT INTO THURSDAY MORNING. SHOWERS AND ISOLATED THUNDERSTORMS
WILL CONTINUE INTO THE EVENING WITH THE HIGHEST PROBABILITY
SHIFTING SEWD. SHORTWAVE RIDING THEN MOVES IN FOR A DRY AND WARMER
THURSDAY. BL LOOKS MOIST LATE TONIGHT SO COULD DEFINITELY SEE LOW
CLOUDS AND OR FOG IN OUR SERN ZONES WHERE LIGHT WINDS AND RECENT
RAINFALL HELP OUT.

.LONG TERM...THURSDAY NIGHT THROUGH WEDNESDAY

THE TROUGH THAT IS GIVING SOUTHERN AND EAST CENTRAL WYOMING RAIN
TODAY WILL BE EXITING EAST ACROSS THE PLAINS BY THURSDAY NIGHT. THEN
A FAST MOVING SHORTWAVE WILL BE SCOOTING RAPIDLY EAST ACROSS MONTANA
FRIDAY. THE FLOW OVER WYOMING SOUTH OF THIS SHORTWAVE WILL BE
WESTERLY AND SLIGHTLY DIFLUENT. THE LIFT FROM THIS SHORTWAVE WILL
REMAIN TO THE NORTH IN MONTANA. HIGHER CAPES ARE PROGGED FOR JOHNSON
COUNTY FRIDAY ALONG WITH JUST SLIGHTLY NEGATIVE LIFTED INDICES.
MARGINAL AMOUNTS OF MOISTURE ARE PROGGED FOR FAR NORTHERN WY FRIDAY
WITH MOST OF THE 500-700MB MOISTURE REMAINING UP IN MONTANA. WENT
WITH JUST SCATTERED SHOWERS IN THE NORTHERN MTNS FOR FRIDAY AS WELL
AS IN THE WIND RIVER MOUNTAINS.

THE GFS HAS COME MORE IN LINE WITH THE ECMWF IN THAT IT IS BRINGING
A SHORTWAVE/COLD FRONT THROUGH OUR CWA SATURDAY AND ANOTHER ONE ON MONDAY
ALONG WITH THE ASCT LONG WAVE TROUGH TO PASS THROUGH SUNDAY. HAVE
KEPT WIDESPREAD/NUMEROUS SHOWERS AND A FEW THUNDERSTORMS ACROSS THE
AREA FOP SATURDAY ASCT WITH THE SHORTWAVE...ESP IN THE AFTERNOON AND
IN THE NORTHWEST. ELSEWHERE ON SATURDAY AHEAD OF THE COLD
FRONT...WARM...BREEZY AND DRY CONDITIONS ARE EXPECTED...ESPECIALLY
FROM RKS TO CPR...WHERE FIRE WEATHER CONCERNS WILL LIKELY BE SOMEWHAT
ELEVATED. IN FACT...SATURDAY APPEARS TO BE THE WARMEST DAY OF THE
WEEK WITH HIGHS IN THE 80S EXPECTED AT THE LOWER ELEVATIONS EAST OF
THE DIVIDE AND 70S WEST. H7 TEMPS BEHIND THIS TROUGH/COLD FRONT WILL
DROP TO NEAR ZERO IN NORTHERN WY BY SUNDAY WHICH WOULD BRING THE
SNOW LEVEL DOWN TO 8500 FEET IN THE NORTHERN MTNS. MAINLY SCATTERED
SHOWERS ARE EXPECTED FOR COVERAGE SUNDAY WITH THE LONG WAVE TROUGH.
SCATTERED SHOWER ACTIVITY IS STILL EXPECTED MONDAY WITH THE NEXT
SHORTWAVE. NOT MUCH IN THE WAY OF THUNDERSTORM ACTIVITY ANYWHERE IS
EXPECTED AFTER SATURDAY WITH THE STABILIZING AIR MASS...MAINLY JUST
SHOWERS. WITH A CONTINUED WESTERLY...SOMEWHAT MOIST PACIFIC
FLOW...STILL EXPECTING SOME ISOLATED SHOWERS IN THE HIGHEST FAR NW
MTNS TUESDAY. THIS WESTERLY FLOW WILL RESULT IN JUST DRY CONDITIONS
IN MOST AREAS OF THE CWA TUESDAY. THEN BY WEDNESDAY...THE WEST
SOUTHWEST FLOW WILL INCREASE AHEAD OF AN APPROACHING STRONG CUT OFF
LOW DIVING DOWN SOUTHEAST INTO THE PAC NW WHICH WILL RESULT IN ISOLD
TO WIDELY SCATTERED SHOWERS IN THE NW MTNS AS THE FASTER MORE FALL
LIKE PROGRESSIVE FLOW PATTERN APPEARS TO BECOME ESTABLISHED FOR
NOW.

&&

.AVIATION.../00Z ISSUANCE/

SHOWERS AND ISOLATED THUNDERSTORMS WILL CONTINUE ACROSS MUCH OF
SWEETWATER...FREMONT AND NATRONA COUNTIES TODAY WITH
KLND...KRIW...KRKS AND KCPR MOST AFFECTED THROUGH ABOUT 03Z. SEE
TERMINAL FORECASTS FOR MORE DETAILS. A LESSER CHANCE OF SHOWERS AND
ISOLATED THUNDERSTORMS EXIST FURTHER WEST AND NORTH FROM THIS EAR.
AREAS OF MVFR TO LOCAL IFR WILL OCCUR DURING PERIODS OF HEAVIER
SHOWERS. AS SHOWERS END OR DECREASE TO ISOLATED SHOWERS LATER
TONIGHT...AREAS OF LOW CLOUDS AND FOG WILL DEVELOP OVER THE AREAS
THAT RECEIVED GOOD RAIN WITH LCL TO AREAS OF MVFR TO EVEN IFR
POTENTIALLY IMPACTING KRKS AND KCPR BETWEEN 06Z AND 15Z THURSDAY.

OVER THE NORTH VFR CONDITIONS WILL PREVAIL. ISOLATED SHOWERS AND
STORMS WILL OCCUR UNTIL 02Z...MAINLY OVER AND NEAR THE MOUNTAINS.

&&

.FIRE WEATHER...

AN AREA OF LOW PRESSURE MOVING ALONG THE WYOMING AND COLORADO BORDER
WILL KEEP SHOWERS AND ISOLATED THUNDERSTORMS INTO EARLY THIS EVENING.
MOST SHOWER ACTIVITY WILL IMPACT THE SERN HALF OF THE FORECAST
AREA...THOUGH SOME AREAS OF NORTHERN WYOMING WILL SEE THE
POTENTIAL FOR ISOLATED ACTIVITY THROUGH THE EARLY EVENING HOURS.
THURSDAY WILL BE WARMER AND DRIER BUT WITH NO SIGNIFICANT WINDS. A
WEAK SYSTEM WILL PASS ACROSS THE NORTH ON FRIDAY WITH ISOLATED
SHOWERS AND THUNDERSTORMS AND AREAS OF BREEZY TO LOCALLY WINDY
CONDITIONS.

&&

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

&&

$$

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






000
FXUS65 KRIW 271846
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
1246 PM MDT WED AUG 27 2014

.SHORT TERM...TODAY THROUGH FRIDAY NIGHT

QUIET CONDITIONS NOTED OVER THE FORECAST AREA FOR NOW...THOUGH
COOLING CLOUDS ARE MOVING INTO SOUTHERN SWEETWATER COUNTY. THE
ANTICIPATED AREA OF LOW PRESSURE IS ANTICIPATED TO BE OVER
NORTHEASTERN UTAH THIS MORNING...AND CONTINUE TO MOVE EASTWARD. THIS
SYSTEM WILL RESULT IN SHOWERS AND POSSIBLY THUNDERSTORMS ACROSS
SWEETWATER COUNTY THIS MORNING...WITH ACTIVITY SPREADING NORTH
THROUGH THE MORNING HOURS. MUCH OF THE SOUTHERN TWO THIRDS OF THE
STATE WILL SEE THE POTENTIAL FOR SHOWER ACTIVITY BY NOON TODAY.

AS THE SYSTEM PROGRESSES THIS AFTERNOON...IT WILL TURN INTO AN OPEN
WAVE INSTEAD OF A CLOSED LOW. SHOWERS AND THUNDERSTORMS WILL
CONTINUE AS THE WAVE MOVES FURTHER EAST. PRECIPITABLE WATER VALUES
REMAIN ELEVATED...INDICATING THE POTENTIAL FOR PERIODS OF HEAVY RAIN
TODAY...ALONG WITH GUSTY WIND AND SMALL HAIL.

THE WAVE WILL BE MOSTLY EAST OF THE AREA BY LATE TONIGHT...WITH DRY
CONDITIONS EXPECTED OVER WESTERN AND CENTRAL WYOMING. A FEW SHOWERS
MAY LINGER ACROSS SOUTHEASTERN WYOMING AS THE SYSTEM DEPARTS...BUT
WIDESPREAD DRY CONDITIONS ARE EXPECTED BY LATE THURSDAY AFTERNOON. A
RELATIVELY FLAT RIDGING PATTERN WORKS TO BUILD OVER THE AREA LATE
THURSDAY AND INTO FRIDAY. WEST TO NORTHWEST FLOW IS ANTICIPATED OVER
THE AREA.

A WEAK WAVE EMBEDDED WITHIN THIS SYSTEM WILL BRING LEAVE WEAK
MOISTURE TRAPPED IN THE SYSTEM LATE THURSDAY. THIS TRAPPED MOISTURE
MAY CREATE SOME ISOLATED TO WIDELY SCATTERED SHOWERS AND
THUNDERSTORMS FRIDAY MORNING...WITH ACTIVITY CONTINUING INTO FRIDAY
AFTERNOON AND EVENING.

.LONG TERM...SATURDAY THROUGH WEDNESDAY
A FAIRLY ACTIVE LABOR DAY WEEKEND IS IN STORE FOR THE COWBOY STATE
AS A TROUGH SETTLES OVER THE REGION. MODELS HAVE SLIGHTLY SPED UP
THE TROUGH AND THE INITIAL COLD FRONT. THIS COLD FRONT IS NOW
EXPECTED TO PUSH INTO THE WEST SATURDAY...AND ACROSS THE REST OF THE
AREA SATURDAY NIGHT. AHEAD OF THE FRONT...WINDY AND WARM CONDITIONS
ARE EXPECTED WITH THE POSSIBILITY OF ELEVATED/EXTREME FIRE WEATHER
CONDITIONS...MAINLY OVER THE SOUTH AND THE ROCK SPRINGS TO CASPER
CORRIDOR. IN ADDITION...THE TREND OF A FASTER SOLUTION HAS MEANT
INCREASING/EXPANDING POPS SATURDAY/SATURDAY NIGHT. ONCE THE TROUGH
SETS UP OVER THE ROCKIES...ADDITIONAL SHORTWAVES OF VARYING
INTENSITIES SHOULD PUSH THROUGH THE TROUGH IMPACTING THE FORECAST
AREA IN THE SUNDAY/MONDAY TIME FRAME. DUE TO THE UNCERTAINTY WITH
TIMING/STRENGTH OF ANY WAVE WILL BROAD BRUSH POPS SUNDAY AND MONDAY
WITH AN EMPHASIS ACROSS THE NORTHERN MOUNTAINS. COULD EASILY SEE
SOME MOUNTAIN SNOW ACCUMULATIONS SUNDAY AND MONDAY ABOVE 9500 FEET.

BY TUESDAY...MODELS ARE SHOWING A MAINLY DRY WESTERLY FLOW. HOWEVER
THIS COULD BE SHORT LIVED AS ANOTHER TROUGH POSSIBLY BEGINS TO
IMPACT THE AREA NEXT WEDNESDAY AND THURSDAY.

&&

.AVIATION.../18Z ISSUANCE/

SHOWERS AND ISOLATED THUNDERSTORMS WILL CONTINUE ACROSS MUCH OF
SWEETWATER...FREMONT AND NATRONA COUNTIES TODAY WITH
KLND...KRIW...KRKS AND KCPR MOST AFFECTED THROUGH ABOUT 03Z. SEE
TERMINAL FORECASTS FOR MORE DETAILS. A LESSER CHANCE OF SHOWERS
AND ISOLATED THUNDERSTORMS EXIST FURTHER WEST AND NORTH FROM THIS
EAR. AREAS OF MVFR TO LOCAL IFR WILL OCCUR DURING PERIODS OF
HEAVIER SHOWERS. AS SHOWERS END OR DECREASE TO ISOLATED SHOWERS
LATER TONIGHT...AREAS OF LOW CLOUDS AND FOG WILL DEVELOP OVER THE
AREAS THAT RECEIVED GOOD RAIN WITH LCL TO AREAS OF MVFR TO EVEN
IFR POTENTIALLY IMPACTING KRKS AND KCPR BETWEEN 06Z AND 15Z
THURSDAY.

OVER THE NORTH VFR CONDITIONS WILL PREVAIL. ISOLATED SHOWERS AND
STORMS WILL OCCUR UNTIL 02Z...MAINLY OVER AND NEAR THE MOUNTAINS.

&&

.FIRE WEATHER...

AN AREA OF LOW PRESSURE MOVING ALONG THE WYOMING AND COLORADO BORDER
WILL KEEP SHOWERS AND THUNDERSTORMS PRESENT TODAY. MOST SHOWER
ACTIVITY WILL IMPACT THE SOUTHERN TWO THIRDS OF THE FORECAST
AREA...THOUGH SOME AREAS OF NORTHERN WYOMING WILL SEE THE POTENTIAL
FOR ISOLATED ACTIVITY THROUGH THE EARLY EVENING HOURS. MOISTURE
LOOKS PLENTIFUL WITH THIS SYSTEM...INDICATING THE POTENTIAL FOR SOME
HEAVY RAINFALL WITH STORMS. GUSTY WIND AND SMALL HAIL WILL ALSO BE
THREATS WITH ACTIVITY TODAY. ACTIVITY WILL WANE TONIGHT AS THE WAVE
MOVES FURTHER EAST. DRY CONDITIONS THEN ANTICIPATED THROUGH FRIDAY
MORNING...WITH RETURNING SHOWERS AND THUNDERSTORMS POSSIBLE ACROSS
NORTHERN WYOMING DURING THE AFTERNOON HOURS. COOLING TEMPERATURES
TODAY WILL COMBINE WITH INCREASED MOISTURE TO KEEP FIRE WEATHER
CONCERNS MINIMAL TODAY...AND POTENTIALLY THROUGH FRIDAY AFTERNOON.

&&

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

&&

$$

SHORT TERM...BRANHAM
LONG TERM...WM
AVIATION...AR
FIRE WEATHER...BRANHAM









000
FXUS65 KCYS 271737
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
1137 AM MDT WED AUG 27 2014

.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 355 AM MDT WED AUG 27 2014

CLOSED UPPER LOW WAS ENTERING UT FROM NV PER WATER VAPOR IMAGERY.
SOUTHERLY FLOW ALOFT DRAWING MOISTURE FROM HURRICANE MARIE WEST OF
BAJA CA INTO THE CENTRAL AND SOUTHERN ROCKY MOUNTAIN REGION.
SHORTWAVE LIFTING NORTHWARD ACROSS NORTHWEST CO PRODUCING SCATTERED
SHOWERS AND ISOLATED TSTORMS. OTHER CONVECTION WAS DEVELOPING NORTH
OF A STALLED SURFACE FRONT FROM NORTHEAST CO INTO CENTRAL NE. SKIES
WERE PARTLY TO MOSTLY CLOUDY WITH SOME STRATUS FORMING OVER EAST
CENTRAL WY. WINDS WERE LIGHT AND VARIABLE.

THE 00Z SHORT RANGE MODEL GUIDANCE IS IN GOOD AGREEMENT PROGGING THE
UPPER LOW PRESSURE CENTER EVOLVING INTO A OPEN WAVE AS IT PROGRESSES
SLOWLY EAST INTO WESTERN CO THIS AFTERNOON. THE MAJORITY OF THE
MODELS INCLUDING THE ESRL HRRR DEVELOP AN WEST-EAST BAND OF SHOWERS
AND EMBEDDED TSTORMS ALONG THE I-80 CORRIDOR AFTER 12Z AS THE
SHORTWAVE LIFTS NORTH INTO SOUTHERN WY. ADDITIONAL SHOWERS AND
SCATTERED TSTORMS DEVELOP THIS AFTERNOON WITH UPSLOPE SOUTHEASTERLY
FLOW. LOW/MID LEVEL INSTABILITY AND 0-6KM SHEAR PROFILES ARE NOT
CONDUCIVE FOR SEVERE TSTORM DEVELOPMENT...HOWEVER PRECIP WATER
VALUES EXCEED AN INCH MORE INDICATIVE OF LOCALLY HEAVY RAINFALL.
STORM MOTION WILL BE TO THE NORTH AND NORTHEAST AROUND 25 KT WHICH
SHOULD MITIGATE THE FLOOD THREAT. FOLLOWED THE HPC QPF WHICH PROGS
0.5-1.0 INCH RAINFALL OVER THE CWA. IT WILL BE 5-10 DEGREES COOLER
TODAY COMPARED TO YESTERDAY WITH 700MB TEMPERATURES AROUND 7C.
SHOWER COVERAGE WILL DECREASE FROM NUMEROUS THIS EVENING TO LOW END
SCATTERED LATER TONIGHT.

THURSDAY WILL TREND DRIER AS THE UPPER TROUGH AND BETTER MOISTURE
SHIFT SOUTH AND EAST OF THE CWA. STILL CANNOT RULE OUT ISOLATED TO
SCATTERED CONVECTION ALONG AND SOUTH OF I-80 THOUGH. QPF WILL BE
LIGHTER...GENERALLY LESS THAN A QUARTER INCH. HIGH TEMPERATURES WILL
BE 3-5 DEGREES WARMER...ESPECIALLY EAST CENTRAL WY AND NORTHERN NE
PANHANDLE WITH GREATER INSOLATION.

TRANSITORY SHORTWAVE RIDGE THURSDAY NIGHT SHIFTS EAST FRIDAY AS A
SHORTWAVE TROUGH MOVES EAST ACROSS MT AND NORTHERN WY. THIS SYSTEM
WILL NOT HAVE MUCH AVAILABLE MOISTURE TO WORK WITH...BUT DYNAMICS
ENOUGH TO OVERCOME AND PRODUCE ISOLATED AFTERNOON CONVECTION ALONG
AND NORTH OF A LINE FROM DOUGLAS TO CHADRON...AS WELL AS OVER THE
MOUNTAINS. 700MB TEMPERATURES RISE TO AROUND 10C FRIDAY AFTERNOON
WITH READINGS IN THE 80S EAST OF THE LARAMIE RANGE.

.LONG TERM...(FRIDAY NIGHT THROUGH TUESDAY)
ISSUED AT 330 AM MDT WED AUG 27 2014

MILD AND MAINLY DRY WEATHER FRI NIGHT INTO SATURDAY AS A MINOR UPPER
RIDGE MOVES EAST ACROSS THE AREA. A QUICK-MOVING SHORTWAVE SHOULD
PASS MAINLY NORTH OF THE CWA LATE SAT BUT COULD BRING A FEW SHOWERS
TO MAINLY NORTHERN PARTS OF THE CWA THEN. MORE SIGNIFICANT UPPER TROF
WILL MOVE ACROSS SUNDAY BRINGING MORE WIDESPREAD SHOWERS AND A FEW
TSTMS. ECMWF MORE BULLISH WITH THIS SYSTEM WITH THE GFS CONSIDERABLY
WEAKER. MILD AND MAINLY DRY WEATHER RETURNS FOR MONDAY AND TUESDAY
AS THE CWA RESIDES ON THE SOUTHERN SIDE OF BROAD UPPER CYCLONIC FLOW
THAT WILL PROGRESS ACROSS THE NORTHERN PART OF THE COUNTRY.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY MORNING)
ISSUED AT 1130 AM MDT WED AUG 27 2014

SCATTERED TO NUMEROUS SHOWERS AND STORMS CAN BE EXPECTED ACROSS
SOUTHEAST WY AND THE WESTERN NE PANHANDLE TODAY. MOST TERMINALS
WILL SEE LOWER CIGS BETWEEN 5K AND 8K FEET AGL THROUGH THE TAF
PERIOD...WITH OCCASIONAL MVFR CONDITIONS WITH BKN-TO-OVC SKIES
AROUND 2K FEET. LOWEST CIGS/VSBYS WILL OCCUR BENEATH SHOWERS AND
STORMS. A FEW STRONGER STORMS ARE POSSIBLE THIS AFTN FOR THE NE
PANHANDLE SITES...WITH TORRENTIAL DOWNPOURS AND STRONG/VARIABLE
WINDS POSSIBLE ALONG WITH SMALL HAIL. SHOWER ACTIVITY IS LIKELY
TO PERSIST ACROSS MUCH OF THE REGION OVERNIGHT. WE CANNOT RULE
OUT MVFR CIGS LATE TONIGHT OR EARLY THU...ESPECIALLY IN AREAS
WHICH RECIEVE HEAVIER RAINFALL THIS AFTN.

&&

.FIRE WEATHER...
ISSUED AT 252 AM MDT WED AUG 27 2014

A LOW PRESSURE SYSTEM OVER UTAH EARLY THIS MORNING WILL SLOWLY TRACK
EAST THROUGH COLORADO DURING THE NEXT 24 HOURS...AND INTO THE CENTRAL
PLAINS BY FRIDAY. NUMEROUS SHOWERS AND SCATTERED THUNDERSTORMS WILL
PRODUCE WETTING RAINFALL TODAY AND TONIGHT. DRIER AND WARMER WEATHER
WILL RETURN THURSDAY AND CONTINUE THROUGH SATURDAY...ALONG WITH GUSTY
WEST TO SOUTHWEST WINDS. THERE WILL BE A SLIGHT CHANCE OF SHOWERS
AND THUNDERSTORMS SUNDAY AND LABOR DAY WITH THE PASSAGE OF A UPPER
LEVEL TROUGH AND PACIFIC COLD FRONT.

&&

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

$$

SHORT TERM...JAMSKI
LONG TERM...RE
AVIATION...HAMMER
FIRE WEATHER...JAMSKI






000
FXUS65 KCYS 271737
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
1137 AM MDT WED AUG 27 2014

.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 355 AM MDT WED AUG 27 2014

CLOSED UPPER LOW WAS ENTERING UT FROM NV PER WATER VAPOR IMAGERY.
SOUTHERLY FLOW ALOFT DRAWING MOISTURE FROM HURRICANE MARIE WEST OF
BAJA CA INTO THE CENTRAL AND SOUTHERN ROCKY MOUNTAIN REGION.
SHORTWAVE LIFTING NORTHWARD ACROSS NORTHWEST CO PRODUCING SCATTERED
SHOWERS AND ISOLATED TSTORMS. OTHER CONVECTION WAS DEVELOPING NORTH
OF A STALLED SURFACE FRONT FROM NORTHEAST CO INTO CENTRAL NE. SKIES
WERE PARTLY TO MOSTLY CLOUDY WITH SOME STRATUS FORMING OVER EAST
CENTRAL WY. WINDS WERE LIGHT AND VARIABLE.

THE 00Z SHORT RANGE MODEL GUIDANCE IS IN GOOD AGREEMENT PROGGING THE
UPPER LOW PRESSURE CENTER EVOLVING INTO A OPEN WAVE AS IT PROGRESSES
SLOWLY EAST INTO WESTERN CO THIS AFTERNOON. THE MAJORITY OF THE
MODELS INCLUDING THE ESRL HRRR DEVELOP AN WEST-EAST BAND OF SHOWERS
AND EMBEDDED TSTORMS ALONG THE I-80 CORRIDOR AFTER 12Z AS THE
SHORTWAVE LIFTS NORTH INTO SOUTHERN WY. ADDITIONAL SHOWERS AND
SCATTERED TSTORMS DEVELOP THIS AFTERNOON WITH UPSLOPE SOUTHEASTERLY
FLOW. LOW/MID LEVEL INSTABILITY AND 0-6KM SHEAR PROFILES ARE NOT
CONDUCIVE FOR SEVERE TSTORM DEVELOPMENT...HOWEVER PRECIP WATER
VALUES EXCEED AN INCH MORE INDICATIVE OF LOCALLY HEAVY RAINFALL.
STORM MOTION WILL BE TO THE NORTH AND NORTHEAST AROUND 25 KT WHICH
SHOULD MITIGATE THE FLOOD THREAT. FOLLOWED THE HPC QPF WHICH PROGS
0.5-1.0 INCH RAINFALL OVER THE CWA. IT WILL BE 5-10 DEGREES COOLER
TODAY COMPARED TO YESTERDAY WITH 700MB TEMPERATURES AROUND 7C.
SHOWER COVERAGE WILL DECREASE FROM NUMEROUS THIS EVENING TO LOW END
SCATTERED LATER TONIGHT.

THURSDAY WILL TREND DRIER AS THE UPPER TROUGH AND BETTER MOISTURE
SHIFT SOUTH AND EAST OF THE CWA. STILL CANNOT RULE OUT ISOLATED TO
SCATTERED CONVECTION ALONG AND SOUTH OF I-80 THOUGH. QPF WILL BE
LIGHTER...GENERALLY LESS THAN A QUARTER INCH. HIGH TEMPERATURES WILL
BE 3-5 DEGREES WARMER...ESPECIALLY EAST CENTRAL WY AND NORTHERN NE
PANHANDLE WITH GREATER INSOLATION.

TRANSITORY SHORTWAVE RIDGE THURSDAY NIGHT SHIFTS EAST FRIDAY AS A
SHORTWAVE TROUGH MOVES EAST ACROSS MT AND NORTHERN WY. THIS SYSTEM
WILL NOT HAVE MUCH AVAILABLE MOISTURE TO WORK WITH...BUT DYNAMICS
ENOUGH TO OVERCOME AND PRODUCE ISOLATED AFTERNOON CONVECTION ALONG
AND NORTH OF A LINE FROM DOUGLAS TO CHADRON...AS WELL AS OVER THE
MOUNTAINS. 700MB TEMPERATURES RISE TO AROUND 10C FRIDAY AFTERNOON
WITH READINGS IN THE 80S EAST OF THE LARAMIE RANGE.

.LONG TERM...(FRIDAY NIGHT THROUGH TUESDAY)
ISSUED AT 330 AM MDT WED AUG 27 2014

MILD AND MAINLY DRY WEATHER FRI NIGHT INTO SATURDAY AS A MINOR UPPER
RIDGE MOVES EAST ACROSS THE AREA. A QUICK-MOVING SHORTWAVE SHOULD
PASS MAINLY NORTH OF THE CWA LATE SAT BUT COULD BRING A FEW SHOWERS
TO MAINLY NORTHERN PARTS OF THE CWA THEN. MORE SIGNIFICANT UPPER TROF
WILL MOVE ACROSS SUNDAY BRINGING MORE WIDESPREAD SHOWERS AND A FEW
TSTMS. ECMWF MORE BULLISH WITH THIS SYSTEM WITH THE GFS CONSIDERABLY
WEAKER. MILD AND MAINLY DRY WEATHER RETURNS FOR MONDAY AND TUESDAY
AS THE CWA RESIDES ON THE SOUTHERN SIDE OF BROAD UPPER CYCLONIC FLOW
THAT WILL PROGRESS ACROSS THE NORTHERN PART OF THE COUNTRY.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY MORNING)
ISSUED AT 1130 AM MDT WED AUG 27 2014

SCATTERED TO NUMEROUS SHOWERS AND STORMS CAN BE EXPECTED ACROSS
SOUTHEAST WY AND THE WESTERN NE PANHANDLE TODAY. MOST TERMINALS
WILL SEE LOWER CIGS BETWEEN 5K AND 8K FEET AGL THROUGH THE TAF
PERIOD...WITH OCCASIONAL MVFR CONDITIONS WITH BKN-TO-OVC SKIES
AROUND 2K FEET. LOWEST CIGS/VSBYS WILL OCCUR BENEATH SHOWERS AND
STORMS. A FEW STRONGER STORMS ARE POSSIBLE THIS AFTN FOR THE NE
PANHANDLE SITES...WITH TORRENTIAL DOWNPOURS AND STRONG/VARIABLE
WINDS POSSIBLE ALONG WITH SMALL HAIL. SHOWER ACTIVITY IS LIKELY
TO PERSIST ACROSS MUCH OF THE REGION OVERNIGHT. WE CANNOT RULE
OUT MVFR CIGS LATE TONIGHT OR EARLY THU...ESPECIALLY IN AREAS
WHICH RECIEVE HEAVIER RAINFALL THIS AFTN.

&&

.FIRE WEATHER...
ISSUED AT 252 AM MDT WED AUG 27 2014

A LOW PRESSURE SYSTEM OVER UTAH EARLY THIS MORNING WILL SLOWLY TRACK
EAST THROUGH COLORADO DURING THE NEXT 24 HOURS...AND INTO THE CENTRAL
PLAINS BY FRIDAY. NUMEROUS SHOWERS AND SCATTERED THUNDERSTORMS WILL
PRODUCE WETTING RAINFALL TODAY AND TONIGHT. DRIER AND WARMER WEATHER
WILL RETURN THURSDAY AND CONTINUE THROUGH SATURDAY...ALONG WITH GUSTY
WEST TO SOUTHWEST WINDS. THERE WILL BE A SLIGHT CHANCE OF SHOWERS
AND THUNDERSTORMS SUNDAY AND LABOR DAY WITH THE PASSAGE OF A UPPER
LEVEL TROUGH AND PACIFIC COLD FRONT.

&&

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

$$

SHORT TERM...JAMSKI
LONG TERM...RE
AVIATION...HAMMER
FIRE WEATHER...JAMSKI







000
FXUS63 KUNR 271646
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
1046 AM MDT WED AUG 27 2014

.UPDATE...
ISSUED AT 1012 AM MDT WED AUG 27 2014

CURRENT SURFACE ANALYSIS SHOWS LOW PRESSURE OVER FAR NORTHEAST
CO...WITH A NEARLY STATIONARY FRONTAL BOUNDARY FROM WESTERN WY TO
NORTHEAST KS. UPPER LEVEL ANALYSIS SHOWS LOW PRESSURE OVER EASTERN
UT...WITH TROF COVERING THE ROCKIES AND MUCH OF THE HIGH PLAINS.
SKIES ARE VARIABLY CLOUDY ACROSS THE AREA...WITH AREAS OF FOG
LIFTING OVER EASTERN PORTIONS OF THE CWA. REGIONAL RADARS SHOW
MOST OF THE SHOWER AND THUNDERSTORM ACTIVITY IN TWO AREAS. THE
MAIN AREA IS OVER SOUTHERN AND CENTRAL WY...MOVING NORTH-
NORTHWESTWARD AROUND THE UPPER LOW. ANOTHER AREA OF LIGHTER
ACTIVITY IS LOCATED OVER CENTRAL NEB INTO PORTIONS OF SOUTHEAST
SD...MOVING NORTH-NORTHEAST. OUR AREA IS DRY AT THE MOMENT...BUT
SHOWERS AND STORMS WILL MOVE IN FROM THE SOUTH AND ALSO DEVELOP
AS THE UPPER LOW MOVES ACROSS SOUTHERN WY/NORTHERN CO THIS
AFTERNOON AND EVENING...ESPECIALLY OVER THE BLACK HILLS AND
SOUTHERN PORTIONS OF THE CWA. THERE SHOULD BE A FAIRLY SHARP
CUT-OFF TO THE COVERAGE OF SHOWERS... LIKELY SOMEWHERE NEAR OR
JUST NORTH OF THE I-90 CORRIDOR. THE THREAT FOR SEVERE STORMS
REMAINS LOW WITH MAIN AREA OF INSTABILITY STAYING SOUTH OF THE
AREA.

HAVE MADE A MINOR UPDATE TO THE FORECAST...MAINLY TO LOWER POPS
ACROSS THE AREA THIS MORNING AND RAISE THEM OVER THE BLACK HILLS
THIS AFTERNOON. ALSO MADE SOME ADJUSTMENTS TO CLOUD COVER FOR THE
NEXT FEW HOURS. TEMP FORECAST FOR TODAY LOOKS GOOD AT THE MOMENT...
BUT MAY HAVE TO TWEAK THEM A BIT LATER ON...DEPENDING ON CLOUD
AND SHOWER COVERAGE.

&&

.SHORT TERM...TODAY THROUGH THURSDAY NIGHT
ISSUED AT 251 AM MDT WED AUG 27 2014

LATEST WATER VAPOR IMAGERY SHOWS AN AREA OF LOW PRESSURE OVER
NEVADA/UTAH WITH A NORTHERN STREAM TROUGH EXTENDING FROM CENTRAL
CANADA INTO THE NORTHERN PLAINS. THE NORTHERN STREAM TROF WILL
QUICKLY MOVE EASTWARD AS THE CUTOFF LOW SLOWLY PROPAGATES INTO THE
CENTRAL ROCKIES. SOUTHWESTERLY FLOW CONTINUES OVER THE
CENTRAL/NORTHERN PLAINS.

FOR TODAY THE BEST FORCING REMAINS SOUTH OF THE CWA. BEST CHANCES
OF PRECIP THROUGH THURSDAY WILL BE ACROSS THE FAR SOUTHERN PORTIONS
OF THE FORECAST AREA AS A SERIES OF WAVES CROSS THE COLORADO/NEBRASKA
AREA. MODELS ARE VARYING WITH TIMING OF WAVES AND HOW FAR NORTH
THE PRECIP WILL EXTEND WITHIN THE CWA. EITHER WAY QPF AMOUNTS WILL
BE LIMITED...EXCEPT WITH THE POSSIBILITY OF SOME STRONGER STORMS
CROSSING AREAS NEAR THE NEBRASKA BORDER. HIGH TEMPERATURES TODAY
WILL ONCE AGAIN BE BELOW AVERAGE DUE TO CLOUD COVER. AS THE UPPER
LOW MOVES THROUGH NEBRASKA/KANSAS...PRECIP CHANCES WILL DIMINISH
ACROSS THE AREA WITH DRY CONDITIONS BY THURSDAY AFTERNOON/EVENING.

&&

.LONG TERM...FRIDAY THROUGH TUESDAY
ISSUED AT 251 AM MDT WED AUG 27 2014

PROGRESSIVE NORTHERN STREAM FLOW WILL CONTINUE THROUGH THE
PERIOD. TWO MAIN SYSTEMS EXPECTED TO AFFECT THE REGION IN THE
PERIOD...A WEAK NORTHERN STREAM TROUGH FRIDAY...AND A MORE ROBUST
LONGWAVE UPPER TROUGH SAT NIGHT INTO MONDAY. FORECAST MODELS IN
GOOD AGREEMENT PER WAVE AMPLITUDE AND TRACK. HOWEVER...SOME
SUBSTANTIAL DIFFERENCES BEGIN TO EMERGE IN THE SUNDAY NIGHT INTO
MONDAY PERIOD BETWEEN THE ECMWF AND GFS...MAINLY THE HANDLING OF
THE NW CONUS SOUTHERN PERIPHERY EJECTING IMPULSE. THE ECMWF HAS A
SOUTHERN BIAS TO THE SYSTEM WITH THE BULK OF LSA PASSING THROUGH
THE FA AS OPPOSED TO A MORE NORTHERN TRACK IN THE GFS...WHICH IS
ALSO FASTER. THE ECMWF SOLUTION WOULD SUPPORT BETTER CHANCES FOR
RAIN IN THE FA HOWEVER MOISTURE LIMITATIONS MAY PRECLUDE ANY
PRECIP TOTALS THEN.

RETAINED PREV POPS FOR FRIDAY AFTERNOON...WITH A SLIGHT UPTICK AND
EXPANSION OF SLIGHT MENTION. FORECAST MODELS CONTINUE TO INDICATE A
SFC TROUGH STALLING ACROSS THE SW HALF FRIDAY...WITH A PASSING UPPER
LEVEL IMPULSE. SUFFICIENT LL MOISTURE ND RESULTING CAPE WOULD BE
CONDUCIVE FOR CONVECTION IN THE AFTERNOON...ESP OVER THE BLACK
HILLS. OTHERWISE...A MORE IMPRESSIVE UPPER LEVEL TROUGH WILL PUSH
OUT OF THE NE PAC AND INTO THE NORTHERN PLAINS...SUPPORTING
INCREASING LSA SAT NIGHT THROUGH SUNDAY NIGHT. BETTER SFC CYCLONE
DEVELOPMENT LOOKS TO REMAIN WELL EAST OF THE REGION...SUPPORTING
MORE ELEVATED/CONVECTIVE CHANCES BEHIND THE SFC TROUGH RATHER THAN
WIDESPREAD DEFORMATION RAINS. HENCE...KEPT POPS IN THE SLIGHT TO
LOW CHANCE CAT FOR NOW...ESP AS DEEPER MOISTURE WILL SHIFT QUICKLY
EAST OUT OF THE REGION. KEPT MOST OF THE REGION DRY MONDAY THROUGH
TUES...WITH UPPER LEVEL RIDGING COMMENCING AND DRY PROFILES.

SEASONAL TEMPS EXPECTED IN MOST OF THE PERIOD...WITH BELOW NORMAL
TEMPS /5-10 DEGREES/ EXPECTED MONDAY AND PERHAPS TUES BEHIND
SUNDAY/S COLD FRONT...ESP NW AREAS.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY)
ISSUED AT 1042 AM MDT WED AUG 27 2014

SCATTERED SHRA/TSRA EXPECTED ACROSS SOUTHERN HALF OF AREA THROUGH
TONIGHT. LOCAL MVFR CIGS/VSBYS EXPECTED WITH THE HEAVIER
PRECIPITATION. AREAS ST/BR ALSO EXPECTED THROUGH THE PERIOD
ALONG/SOUTH OF A LINE FROM KPHP TO KCUT...ALTHOUGH FINAL NORTHERN
EDGE OF ST/BR WILL BE LARGELY DEPENDENT ON HOW FAR NORTH
PRECIPITATION DEVELOPS. NORTHERN HALF OF CWA SHOULD REMAIN LARGE
VFR THROUGH THE PERIOD.

&&

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

$$

UPDATE...26
SHORT TERM...MLS
LONG TERM...JC
AVIATION...HELGESON




000
FXUS63 KUNR 271646
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
1046 AM MDT WED AUG 27 2014

.UPDATE...
ISSUED AT 1012 AM MDT WED AUG 27 2014

CURRENT SURFACE ANALYSIS SHOWS LOW PRESSURE OVER FAR NORTHEAST
CO...WITH A NEARLY STATIONARY FRONTAL BOUNDARY FROM WESTERN WY TO
NORTHEAST KS. UPPER LEVEL ANALYSIS SHOWS LOW PRESSURE OVER EASTERN
UT...WITH TROF COVERING THE ROCKIES AND MUCH OF THE HIGH PLAINS.
SKIES ARE VARIABLY CLOUDY ACROSS THE AREA...WITH AREAS OF FOG
LIFTING OVER EASTERN PORTIONS OF THE CWA. REGIONAL RADARS SHOW
MOST OF THE SHOWER AND THUNDERSTORM ACTIVITY IN TWO AREAS. THE
MAIN AREA IS OVER SOUTHERN AND CENTRAL WY...MOVING NORTH-
NORTHWESTWARD AROUND THE UPPER LOW. ANOTHER AREA OF LIGHTER
ACTIVITY IS LOCATED OVER CENTRAL NEB INTO PORTIONS OF SOUTHEAST
SD...MOVING NORTH-NORTHEAST. OUR AREA IS DRY AT THE MOMENT...BUT
SHOWERS AND STORMS WILL MOVE IN FROM THE SOUTH AND ALSO DEVELOP
AS THE UPPER LOW MOVES ACROSS SOUTHERN WY/NORTHERN CO THIS
AFTERNOON AND EVENING...ESPECIALLY OVER THE BLACK HILLS AND
SOUTHERN PORTIONS OF THE CWA. THERE SHOULD BE A FAIRLY SHARP
CUT-OFF TO THE COVERAGE OF SHOWERS... LIKELY SOMEWHERE NEAR OR
JUST NORTH OF THE I-90 CORRIDOR. THE THREAT FOR SEVERE STORMS
REMAINS LOW WITH MAIN AREA OF INSTABILITY STAYING SOUTH OF THE
AREA.

HAVE MADE A MINOR UPDATE TO THE FORECAST...MAINLY TO LOWER POPS
ACROSS THE AREA THIS MORNING AND RAISE THEM OVER THE BLACK HILLS
THIS AFTERNOON. ALSO MADE SOME ADJUSTMENTS TO CLOUD COVER FOR THE
NEXT FEW HOURS. TEMP FORECAST FOR TODAY LOOKS GOOD AT THE MOMENT...
BUT MAY HAVE TO TWEAK THEM A BIT LATER ON...DEPENDING ON CLOUD
AND SHOWER COVERAGE.

&&

.SHORT TERM...TODAY THROUGH THURSDAY NIGHT
ISSUED AT 251 AM MDT WED AUG 27 2014

LATEST WATER VAPOR IMAGERY SHOWS AN AREA OF LOW PRESSURE OVER
NEVADA/UTAH WITH A NORTHERN STREAM TROUGH EXTENDING FROM CENTRAL
CANADA INTO THE NORTHERN PLAINS. THE NORTHERN STREAM TROF WILL
QUICKLY MOVE EASTWARD AS THE CUTOFF LOW SLOWLY PROPAGATES INTO THE
CENTRAL ROCKIES. SOUTHWESTERLY FLOW CONTINUES OVER THE
CENTRAL/NORTHERN PLAINS.

FOR TODAY THE BEST FORCING REMAINS SOUTH OF THE CWA. BEST CHANCES
OF PRECIP THROUGH THURSDAY WILL BE ACROSS THE FAR SOUTHERN PORTIONS
OF THE FORECAST AREA AS A SERIES OF WAVES CROSS THE COLORADO/NEBRASKA
AREA. MODELS ARE VARYING WITH TIMING OF WAVES AND HOW FAR NORTH
THE PRECIP WILL EXTEND WITHIN THE CWA. EITHER WAY QPF AMOUNTS WILL
BE LIMITED...EXCEPT WITH THE POSSIBILITY OF SOME STRONGER STORMS
CROSSING AREAS NEAR THE NEBRASKA BORDER. HIGH TEMPERATURES TODAY
WILL ONCE AGAIN BE BELOW AVERAGE DUE TO CLOUD COVER. AS THE UPPER
LOW MOVES THROUGH NEBRASKA/KANSAS...PRECIP CHANCES WILL DIMINISH
ACROSS THE AREA WITH DRY CONDITIONS BY THURSDAY AFTERNOON/EVENING.

&&

.LONG TERM...FRIDAY THROUGH TUESDAY
ISSUED AT 251 AM MDT WED AUG 27 2014

PROGRESSIVE NORTHERN STREAM FLOW WILL CONTINUE THROUGH THE
PERIOD. TWO MAIN SYSTEMS EXPECTED TO AFFECT THE REGION IN THE
PERIOD...A WEAK NORTHERN STREAM TROUGH FRIDAY...AND A MORE ROBUST
LONGWAVE UPPER TROUGH SAT NIGHT INTO MONDAY. FORECAST MODELS IN
GOOD AGREEMENT PER WAVE AMPLITUDE AND TRACK. HOWEVER...SOME
SUBSTANTIAL DIFFERENCES BEGIN TO EMERGE IN THE SUNDAY NIGHT INTO
MONDAY PERIOD BETWEEN THE ECMWF AND GFS...MAINLY THE HANDLING OF
THE NW CONUS SOUTHERN PERIPHERY EJECTING IMPULSE. THE ECMWF HAS A
SOUTHERN BIAS TO THE SYSTEM WITH THE BULK OF LSA PASSING THROUGH
THE FA AS OPPOSED TO A MORE NORTHERN TRACK IN THE GFS...WHICH IS
ALSO FASTER. THE ECMWF SOLUTION WOULD SUPPORT BETTER CHANCES FOR
RAIN IN THE FA HOWEVER MOISTURE LIMITATIONS MAY PRECLUDE ANY
PRECIP TOTALS THEN.

RETAINED PREV POPS FOR FRIDAY AFTERNOON...WITH A SLIGHT UPTICK AND
EXPANSION OF SLIGHT MENTION. FORECAST MODELS CONTINUE TO INDICATE A
SFC TROUGH STALLING ACROSS THE SW HALF FRIDAY...WITH A PASSING UPPER
LEVEL IMPULSE. SUFFICIENT LL MOISTURE ND RESULTING CAPE WOULD BE
CONDUCIVE FOR CONVECTION IN THE AFTERNOON...ESP OVER THE BLACK
HILLS. OTHERWISE...A MORE IMPRESSIVE UPPER LEVEL TROUGH WILL PUSH
OUT OF THE NE PAC AND INTO THE NORTHERN PLAINS...SUPPORTING
INCREASING LSA SAT NIGHT THROUGH SUNDAY NIGHT. BETTER SFC CYCLONE
DEVELOPMENT LOOKS TO REMAIN WELL EAST OF THE REGION...SUPPORTING
MORE ELEVATED/CONVECTIVE CHANCES BEHIND THE SFC TROUGH RATHER THAN
WIDESPREAD DEFORMATION RAINS. HENCE...KEPT POPS IN THE SLIGHT TO
LOW CHANCE CAT FOR NOW...ESP AS DEEPER MOISTURE WILL SHIFT QUICKLY
EAST OUT OF THE REGION. KEPT MOST OF THE REGION DRY MONDAY THROUGH
TUES...WITH UPPER LEVEL RIDGING COMMENCING AND DRY PROFILES.

SEASONAL TEMPS EXPECTED IN MOST OF THE PERIOD...WITH BELOW NORMAL
TEMPS /5-10 DEGREES/ EXPECTED MONDAY AND PERHAPS TUES BEHIND
SUNDAY/S COLD FRONT...ESP NW AREAS.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY)
ISSUED AT 1042 AM MDT WED AUG 27 2014

SCATTERED SHRA/TSRA EXPECTED ACROSS SOUTHERN HALF OF AREA THROUGH
TONIGHT. LOCAL MVFR CIGS/VSBYS EXPECTED WITH THE HEAVIER
PRECIPITATION. AREAS ST/BR ALSO EXPECTED THROUGH THE PERIOD
ALONG/SOUTH OF A LINE FROM KPHP TO KCUT...ALTHOUGH FINAL NORTHERN
EDGE OF ST/BR WILL BE LARGELY DEPENDENT ON HOW FAR NORTH
PRECIPITATION DEVELOPS. NORTHERN HALF OF CWA SHOULD REMAIN LARGE
VFR THROUGH THE PERIOD.

&&

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

$$

UPDATE...26
SHORT TERM...MLS
LONG TERM...JC
AVIATION...HELGESON




000
FXUS63 KUNR 271646
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
1046 AM MDT WED AUG 27 2014

.UPDATE...
ISSUED AT 1012 AM MDT WED AUG 27 2014

CURRENT SURFACE ANALYSIS SHOWS LOW PRESSURE OVER FAR NORTHEAST
CO...WITH A NEARLY STATIONARY FRONTAL BOUNDARY FROM WESTERN WY TO
NORTHEAST KS. UPPER LEVEL ANALYSIS SHOWS LOW PRESSURE OVER EASTERN
UT...WITH TROF COVERING THE ROCKIES AND MUCH OF THE HIGH PLAINS.
SKIES ARE VARIABLY CLOUDY ACROSS THE AREA...WITH AREAS OF FOG
LIFTING OVER EASTERN PORTIONS OF THE CWA. REGIONAL RADARS SHOW
MOST OF THE SHOWER AND THUNDERSTORM ACTIVITY IN TWO AREAS. THE
MAIN AREA IS OVER SOUTHERN AND CENTRAL WY...MOVING NORTH-
NORTHWESTWARD AROUND THE UPPER LOW. ANOTHER AREA OF LIGHTER
ACTIVITY IS LOCATED OVER CENTRAL NEB INTO PORTIONS OF SOUTHEAST
SD...MOVING NORTH-NORTHEAST. OUR AREA IS DRY AT THE MOMENT...BUT
SHOWERS AND STORMS WILL MOVE IN FROM THE SOUTH AND ALSO DEVELOP
AS THE UPPER LOW MOVES ACROSS SOUTHERN WY/NORTHERN CO THIS
AFTERNOON AND EVENING...ESPECIALLY OVER THE BLACK HILLS AND
SOUTHERN PORTIONS OF THE CWA. THERE SHOULD BE A FAIRLY SHARP
CUT-OFF TO THE COVERAGE OF SHOWERS... LIKELY SOMEWHERE NEAR OR
JUST NORTH OF THE I-90 CORRIDOR. THE THREAT FOR SEVERE STORMS
REMAINS LOW WITH MAIN AREA OF INSTABILITY STAYING SOUTH OF THE
AREA.

HAVE MADE A MINOR UPDATE TO THE FORECAST...MAINLY TO LOWER POPS
ACROSS THE AREA THIS MORNING AND RAISE THEM OVER THE BLACK HILLS
THIS AFTERNOON. ALSO MADE SOME ADJUSTMENTS TO CLOUD COVER FOR THE
NEXT FEW HOURS. TEMP FORECAST FOR TODAY LOOKS GOOD AT THE MOMENT...
BUT MAY HAVE TO TWEAK THEM A BIT LATER ON...DEPENDING ON CLOUD
AND SHOWER COVERAGE.

&&

.SHORT TERM...TODAY THROUGH THURSDAY NIGHT
ISSUED AT 251 AM MDT WED AUG 27 2014

LATEST WATER VAPOR IMAGERY SHOWS AN AREA OF LOW PRESSURE OVER
NEVADA/UTAH WITH A NORTHERN STREAM TROUGH EXTENDING FROM CENTRAL
CANADA INTO THE NORTHERN PLAINS. THE NORTHERN STREAM TROF WILL
QUICKLY MOVE EASTWARD AS THE CUTOFF LOW SLOWLY PROPAGATES INTO THE
CENTRAL ROCKIES. SOUTHWESTERLY FLOW CONTINUES OVER THE
CENTRAL/NORTHERN PLAINS.

FOR TODAY THE BEST FORCING REMAINS SOUTH OF THE CWA. BEST CHANCES
OF PRECIP THROUGH THURSDAY WILL BE ACROSS THE FAR SOUTHERN PORTIONS
OF THE FORECAST AREA AS A SERIES OF WAVES CROSS THE COLORADO/NEBRASKA
AREA. MODELS ARE VARYING WITH TIMING OF WAVES AND HOW FAR NORTH
THE PRECIP WILL EXTEND WITHIN THE CWA. EITHER WAY QPF AMOUNTS WILL
BE LIMITED...EXCEPT WITH THE POSSIBILITY OF SOME STRONGER STORMS
CROSSING AREAS NEAR THE NEBRASKA BORDER. HIGH TEMPERATURES TODAY
WILL ONCE AGAIN BE BELOW AVERAGE DUE TO CLOUD COVER. AS THE UPPER
LOW MOVES THROUGH NEBRASKA/KANSAS...PRECIP CHANCES WILL DIMINISH
ACROSS THE AREA WITH DRY CONDITIONS BY THURSDAY AFTERNOON/EVENING.

&&

.LONG TERM...FRIDAY THROUGH TUESDAY
ISSUED AT 251 AM MDT WED AUG 27 2014

PROGRESSIVE NORTHERN STREAM FLOW WILL CONTINUE THROUGH THE
PERIOD. TWO MAIN SYSTEMS EXPECTED TO AFFECT THE REGION IN THE
PERIOD...A WEAK NORTHERN STREAM TROUGH FRIDAY...AND A MORE ROBUST
LONGWAVE UPPER TROUGH SAT NIGHT INTO MONDAY. FORECAST MODELS IN
GOOD AGREEMENT PER WAVE AMPLITUDE AND TRACK. HOWEVER...SOME
SUBSTANTIAL DIFFERENCES BEGIN TO EMERGE IN THE SUNDAY NIGHT INTO
MONDAY PERIOD BETWEEN THE ECMWF AND GFS...MAINLY THE HANDLING OF
THE NW CONUS SOUTHERN PERIPHERY EJECTING IMPULSE. THE ECMWF HAS A
SOUTHERN BIAS TO THE SYSTEM WITH THE BULK OF LSA PASSING THROUGH
THE FA AS OPPOSED TO A MORE NORTHERN TRACK IN THE GFS...WHICH IS
ALSO FASTER. THE ECMWF SOLUTION WOULD SUPPORT BETTER CHANCES FOR
RAIN IN THE FA HOWEVER MOISTURE LIMITATIONS MAY PRECLUDE ANY
PRECIP TOTALS THEN.

RETAINED PREV POPS FOR FRIDAY AFTERNOON...WITH A SLIGHT UPTICK AND
EXPANSION OF SLIGHT MENTION. FORECAST MODELS CONTINUE TO INDICATE A
SFC TROUGH STALLING ACROSS THE SW HALF FRIDAY...WITH A PASSING UPPER
LEVEL IMPULSE. SUFFICIENT LL MOISTURE ND RESULTING CAPE WOULD BE
CONDUCIVE FOR CONVECTION IN THE AFTERNOON...ESP OVER THE BLACK
HILLS. OTHERWISE...A MORE IMPRESSIVE UPPER LEVEL TROUGH WILL PUSH
OUT OF THE NE PAC AND INTO THE NORTHERN PLAINS...SUPPORTING
INCREASING LSA SAT NIGHT THROUGH SUNDAY NIGHT. BETTER SFC CYCLONE
DEVELOPMENT LOOKS TO REMAIN WELL EAST OF THE REGION...SUPPORTING
MORE ELEVATED/CONVECTIVE CHANCES BEHIND THE SFC TROUGH RATHER THAN
WIDESPREAD DEFORMATION RAINS. HENCE...KEPT POPS IN THE SLIGHT TO
LOW CHANCE CAT FOR NOW...ESP AS DEEPER MOISTURE WILL SHIFT QUICKLY
EAST OUT OF THE REGION. KEPT MOST OF THE REGION DRY MONDAY THROUGH
TUES...WITH UPPER LEVEL RIDGING COMMENCING AND DRY PROFILES.

SEASONAL TEMPS EXPECTED IN MOST OF THE PERIOD...WITH BELOW NORMAL
TEMPS /5-10 DEGREES/ EXPECTED MONDAY AND PERHAPS TUES BEHIND
SUNDAY/S COLD FRONT...ESP NW AREAS.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY)
ISSUED AT 1042 AM MDT WED AUG 27 2014

SCATTERED SHRA/TSRA EXPECTED ACROSS SOUTHERN HALF OF AREA THROUGH
TONIGHT. LOCAL MVFR CIGS/VSBYS EXPECTED WITH THE HEAVIER
PRECIPITATION. AREAS ST/BR ALSO EXPECTED THROUGH THE PERIOD
ALONG/SOUTH OF A LINE FROM KPHP TO KCUT...ALTHOUGH FINAL NORTHERN
EDGE OF ST/BR WILL BE LARGELY DEPENDENT ON HOW FAR NORTH
PRECIPITATION DEVELOPS. NORTHERN HALF OF CWA SHOULD REMAIN LARGE
VFR THROUGH THE PERIOD.

&&

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

$$

UPDATE...26
SHORT TERM...MLS
LONG TERM...JC
AVIATION...HELGESON




000
FXUS63 KUNR 271646
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
1046 AM MDT WED AUG 27 2014

.UPDATE...
ISSUED AT 1012 AM MDT WED AUG 27 2014

CURRENT SURFACE ANALYSIS SHOWS LOW PRESSURE OVER FAR NORTHEAST
CO...WITH A NEARLY STATIONARY FRONTAL BOUNDARY FROM WESTERN WY TO
NORTHEAST KS. UPPER LEVEL ANALYSIS SHOWS LOW PRESSURE OVER EASTERN
UT...WITH TROF COVERING THE ROCKIES AND MUCH OF THE HIGH PLAINS.
SKIES ARE VARIABLY CLOUDY ACROSS THE AREA...WITH AREAS OF FOG
LIFTING OVER EASTERN PORTIONS OF THE CWA. REGIONAL RADARS SHOW
MOST OF THE SHOWER AND THUNDERSTORM ACTIVITY IN TWO AREAS. THE
MAIN AREA IS OVER SOUTHERN AND CENTRAL WY...MOVING NORTH-
NORTHWESTWARD AROUND THE UPPER LOW. ANOTHER AREA OF LIGHTER
ACTIVITY IS LOCATED OVER CENTRAL NEB INTO PORTIONS OF SOUTHEAST
SD...MOVING NORTH-NORTHEAST. OUR AREA IS DRY AT THE MOMENT...BUT
SHOWERS AND STORMS WILL MOVE IN FROM THE SOUTH AND ALSO DEVELOP
AS THE UPPER LOW MOVES ACROSS SOUTHERN WY/NORTHERN CO THIS
AFTERNOON AND EVENING...ESPECIALLY OVER THE BLACK HILLS AND
SOUTHERN PORTIONS OF THE CWA. THERE SHOULD BE A FAIRLY SHARP
CUT-OFF TO THE COVERAGE OF SHOWERS... LIKELY SOMEWHERE NEAR OR
JUST NORTH OF THE I-90 CORRIDOR. THE THREAT FOR SEVERE STORMS
REMAINS LOW WITH MAIN AREA OF INSTABILITY STAYING SOUTH OF THE
AREA.

HAVE MADE A MINOR UPDATE TO THE FORECAST...MAINLY TO LOWER POPS
ACROSS THE AREA THIS MORNING AND RAISE THEM OVER THE BLACK HILLS
THIS AFTERNOON. ALSO MADE SOME ADJUSTMENTS TO CLOUD COVER FOR THE
NEXT FEW HOURS. TEMP FORECAST FOR TODAY LOOKS GOOD AT THE MOMENT...
BUT MAY HAVE TO TWEAK THEM A BIT LATER ON...DEPENDING ON CLOUD
AND SHOWER COVERAGE.

&&

.SHORT TERM...TODAY THROUGH THURSDAY NIGHT
ISSUED AT 251 AM MDT WED AUG 27 2014

LATEST WATER VAPOR IMAGERY SHOWS AN AREA OF LOW PRESSURE OVER
NEVADA/UTAH WITH A NORTHERN STREAM TROUGH EXTENDING FROM CENTRAL
CANADA INTO THE NORTHERN PLAINS. THE NORTHERN STREAM TROF WILL
QUICKLY MOVE EASTWARD AS THE CUTOFF LOW SLOWLY PROPAGATES INTO THE
CENTRAL ROCKIES. SOUTHWESTERLY FLOW CONTINUES OVER THE
CENTRAL/NORTHERN PLAINS.

FOR TODAY THE BEST FORCING REMAINS SOUTH OF THE CWA. BEST CHANCES
OF PRECIP THROUGH THURSDAY WILL BE ACROSS THE FAR SOUTHERN PORTIONS
OF THE FORECAST AREA AS A SERIES OF WAVES CROSS THE COLORADO/NEBRASKA
AREA. MODELS ARE VARYING WITH TIMING OF WAVES AND HOW FAR NORTH
THE PRECIP WILL EXTEND WITHIN THE CWA. EITHER WAY QPF AMOUNTS WILL
BE LIMITED...EXCEPT WITH THE POSSIBILITY OF SOME STRONGER STORMS
CROSSING AREAS NEAR THE NEBRASKA BORDER. HIGH TEMPERATURES TODAY
WILL ONCE AGAIN BE BELOW AVERAGE DUE TO CLOUD COVER. AS THE UPPER
LOW MOVES THROUGH NEBRASKA/KANSAS...PRECIP CHANCES WILL DIMINISH
ACROSS THE AREA WITH DRY CONDITIONS BY THURSDAY AFTERNOON/EVENING.

&&

.LONG TERM...FRIDAY THROUGH TUESDAY
ISSUED AT 251 AM MDT WED AUG 27 2014

PROGRESSIVE NORTHERN STREAM FLOW WILL CONTINUE THROUGH THE
PERIOD. TWO MAIN SYSTEMS EXPECTED TO AFFECT THE REGION IN THE
PERIOD...A WEAK NORTHERN STREAM TROUGH FRIDAY...AND A MORE ROBUST
LONGWAVE UPPER TROUGH SAT NIGHT INTO MONDAY. FORECAST MODELS IN
GOOD AGREEMENT PER WAVE AMPLITUDE AND TRACK. HOWEVER...SOME
SUBSTANTIAL DIFFERENCES BEGIN TO EMERGE IN THE SUNDAY NIGHT INTO
MONDAY PERIOD BETWEEN THE ECMWF AND GFS...MAINLY THE HANDLING OF
THE NW CONUS SOUTHERN PERIPHERY EJECTING IMPULSE. THE ECMWF HAS A
SOUTHERN BIAS TO THE SYSTEM WITH THE BULK OF LSA PASSING THROUGH
THE FA AS OPPOSED TO A MORE NORTHERN TRACK IN THE GFS...WHICH IS
ALSO FASTER. THE ECMWF SOLUTION WOULD SUPPORT BETTER CHANCES FOR
RAIN IN THE FA HOWEVER MOISTURE LIMITATIONS MAY PRECLUDE ANY
PRECIP TOTALS THEN.

RETAINED PREV POPS FOR FRIDAY AFTERNOON...WITH A SLIGHT UPTICK AND
EXPANSION OF SLIGHT MENTION. FORECAST MODELS CONTINUE TO INDICATE A
SFC TROUGH STALLING ACROSS THE SW HALF FRIDAY...WITH A PASSING UPPER
LEVEL IMPULSE. SUFFICIENT LL MOISTURE ND RESULTING CAPE WOULD BE
CONDUCIVE FOR CONVECTION IN THE AFTERNOON...ESP OVER THE BLACK
HILLS. OTHERWISE...A MORE IMPRESSIVE UPPER LEVEL TROUGH WILL PUSH
OUT OF THE NE PAC AND INTO THE NORTHERN PLAINS...SUPPORTING
INCREASING LSA SAT NIGHT THROUGH SUNDAY NIGHT. BETTER SFC CYCLONE
DEVELOPMENT LOOKS TO REMAIN WELL EAST OF THE REGION...SUPPORTING
MORE ELEVATED/CONVECTIVE CHANCES BEHIND THE SFC TROUGH RATHER THAN
WIDESPREAD DEFORMATION RAINS. HENCE...KEPT POPS IN THE SLIGHT TO
LOW CHANCE CAT FOR NOW...ESP AS DEEPER MOISTURE WILL SHIFT QUICKLY
EAST OUT OF THE REGION. KEPT MOST OF THE REGION DRY MONDAY THROUGH
TUES...WITH UPPER LEVEL RIDGING COMMENCING AND DRY PROFILES.

SEASONAL TEMPS EXPECTED IN MOST OF THE PERIOD...WITH BELOW NORMAL
TEMPS /5-10 DEGREES/ EXPECTED MONDAY AND PERHAPS TUES BEHIND
SUNDAY/S COLD FRONT...ESP NW AREAS.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY)
ISSUED AT 1042 AM MDT WED AUG 27 2014

SCATTERED SHRA/TSRA EXPECTED ACROSS SOUTHERN HALF OF AREA THROUGH
TONIGHT. LOCAL MVFR CIGS/VSBYS EXPECTED WITH THE HEAVIER
PRECIPITATION. AREAS ST/BR ALSO EXPECTED THROUGH THE PERIOD
ALONG/SOUTH OF A LINE FROM KPHP TO KCUT...ALTHOUGH FINAL NORTHERN
EDGE OF ST/BR WILL BE LARGELY DEPENDENT ON HOW FAR NORTH
PRECIPITATION DEVELOPS. NORTHERN HALF OF CWA SHOULD REMAIN LARGE
VFR THROUGH THE PERIOD.

&&

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

$$

UPDATE...26
SHORT TERM...MLS
LONG TERM...JC
AVIATION...HELGESON




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