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000
FXUS65 KCYS 011052
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
452 AM MDT MON SEP 1 2014

.SHORT TERM...(TODAY THROUGH WEDNESDAY NIGHT)
ISSUED AT 427 AM MDT MON SEP 1 2014

AS OF EARLY THIS MORNING ALL SHOWER ACTIVITY IS NORTH OF THE
FORECAST AREA AHEAD OF A QUICK MOVING SHORTWAVE. AS THE WAVE
SLIDES EAST AND DIPS SOUTH...SHOULD SEE SOME SHOWER ACTIVITY SLIP
INTO EAST CENTRAL WYOMING. MAIN SHOWER ACTIVITY WILL HOLD OFF
UNTIL LATE MORNING AND AFTERNOON AS THE BOUNDARY LAYER DESTABILIZES
WITH COOL AIR ALOFT. MOISTURE IS LIMITED SO GENERALLY ONLY
EXPECTING ISOLATED ACTIVITY ACROSS NORTHERN AND EASTERN PORTIONS
OF THE FORECAST AREA TODAY. COULD SEE A FEW LIGHTNING STRIKES TODAY
BUT THUNDERSTORM ACTIVITY WILL BE LIMITED. NOT LOOKING FOR SEVERE
THUNDERSTORMS BUT WITH RELATIVELY STRONG WINDS ALOFT STRONG
CONVECTIVE GUSTS WILL BE POSSIBLE THIS AFTERNOON WITH SHOWERS AND
THUNDERSTORMS.

SUBSIDENCE WILL SET IN TONIGHT BEHIND THE SHORTWAVE AND DEPARTING
UPPER LEVEL JET. DRY LOW LEVEL AIR AND CLEAR SKIES WILL ALLOW
TEMPERATURES TO DIP INTO THE 40S ACROSS MOST OF THE AREA AGAIN
TONIGHT. TUESDAY WILL BE SUNNY AND BREEZY EAST TO WINDY WEST.
GUSTS OVER 40 MPH WILL OCCUR WEST OF THE LARAMIE RANGE TUESDAY
AFTERNOON WITH GUSTS 20 TO 30 MPH EAST OF THE LARAMIE RANGE. UPPER
LEVEL RIDGE WILL BUILD NORTH ACROSS THE ROCKIES WEDNESDAY WITH
VERY WARM AIR RETURNING TO THE FORECAST AREA. SHOULD SEE 80S WEST
WITH LOWER TO MID 90S FOR PORTIONS OF THE NEBRASKA PANHANDLE.
WINDS WILL GENERALLY NOT BE AS STRONG WEDNESDAY AFTERNOON BUT
STILL QUITE BREEZY.


.LONG TERM...(THURSDAY THROUGH SUNDAY)
ISSUED AT 440 AM MDT MON SEP 1 2014

COOLER WEATHER ACROSS THE CWA THURSDAY WITH A FEW SHOWERS POSSIBLE
AHEAD OF A POSITIVELY TILTED UPPER TROF OVER THE NORTHWEST PART OF
THE COUNTRY. A BETTER CHANCE FOR SHOWERS FOR FRIDAY AS THE TROF
NEARS AND SOME MONSOONAL MOISTURE TRIES TO LIFT NORTHEAST OVER THE
AREA. CONTINUED MILD THROUGH THE WEEKEND BUT MODELS DIVERGE ON
HANDLING OF MONSOONAL MOISTURE WITH THE EC SUPPRESSING IT
SOUTHWARD OF THE CWA WITH A RATHER ZONAL FLOW OVER THE AREA WHILE
THE GFS KEEPS AT LEAST SOME OF IT ADVECTING ACROSS THE CWA THROUGH
SUNDAY. MOST MODELS ARE MORE FAVORING TOWARDS THE EC AND WILL LEAN
IN THAT DIRECTION BUT NOT DRY THINGS OUT COMPLETELY UNTIL ABOUT
SUNDAY.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 440 AM MDT MON SEP 1 2014

VFR EXPECTED OVER ALL AERODROMES THROUGH TUESDAY. ISOLATED SHOWERS
AND TSTMS WILL BE POSSIBLE MAINLY OVER THE NE HALF OF THE NEB
PANHANDLE THIS AFTERNOON AND EVENING.

&&

.FIRE WEATHER...
ISSUED AT 407 AM MDT MON SEP 1 2014

A CHANGE IN THE WEATHER PATTERN WILL LEAVE THE NEBRASKA PANHANDLE
AND SOUTHEAST WYOMING WITH DRY AND BREEZY CONDITIONS THE NEXT SEVERAL
DAYS. A FEW ISOLATED SHOWERS AND STORMS ARE POSSIBLE TODAY BUT
TUESDAY THROUGH THURSDAY WILL BE DRY WITH THE NEXT DECENT SHOT
AT WETTING RAIN NOT UNTIL SATURDAY. MARGINAL CRITICAL FIRE
CONDITIONS FOR PORTIONS OF SOUTHEAST WYOMING TODAY...BUT CRITICAL
FIRE CONDITIONS MORE LIKELY TUESDAY AND WEDNESDAY. CRITICAL
CONDITIONS NOT OUT OF THE QUESTION INTO THE NEBRASKA PANHANDLE
TUESDAY AND WEDNESDAY.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...FIRE WEATHER WATCH FROM TUESDAY AFTERNOON THROUGH TUESDAY
     EVENING FOR WYZ301-303-304-308-309.

NE...NONE.

&&

$$

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





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000
FXUS65 KRIW 011012
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
412 AM MDT MON SEP 1 2014

.SHORT TERM...TODAY THROUGH WEDNESDAY NIGHT

THE LAST SHORT WAVE THAT COULD STIR UP MORE SHOWERS AND STORMS MOVES
THROUGH TODAY WITH EVENTUAL CLEARING WEST TO EAST AS THE MAIN TROUGH
CONTINUES TO MOVE INTO THE PLAINS. A FEW STRONGER STORMS MAY OCCUR
OVR JOHNSON COUNTY BY EARLY AFTERNOON WHERE SOME USEFUL MOISTURE
WILL STILL BE LEFTOVER...CAPE WILL BE MARGINAL BUT SHEAR WILL BE
DECENT AROUND A LEFTOVER BOUNDARY. THERE WILL ALSO BE SOME CONTINUED
BREEZY CONDITIONS AS THE SUBSIDENT SIDE OF THE TROUGH SWINGS THROUGH
AND FLOW SHIFTS TO THE NORTHWEST.

MUCH DRIER AIR MOVES IN ON TUESDAY AS FLOW TURNS MORE ZONAL. HIGH
PRESSURE BUILDING IN FROM THE SOUTH WILL ALSO BRING SOME WARMER AIR
WITH TEMPERATURES REBOUNDING BACK TO NEAR 80 EAST OF THE DIVIDE. THERE
COULD BE SOME GUSTS TO 30 MPH ACROSS THE SOUTH ON TUESDAY...WHICH
COULD LEAD TO SOME FIRE WEATHER CONCERNS IN AREAS WITH FLASHY GRASSY
FUELS.

WEDNESDAY...SOME MODEL SOLUTIONS ARE ADVERTISING ANOTHER UPPER LEVEL
TROUGH WITH SHARP COLD FRONT AND BAROCLINIC ZONE DROPPING SOUTH INTO
MONTANA...AT THIS TIME IT LOOKS LIKE WE WOULD NOT SEE MUCH FROM THE
FRONT UNTIL LATE WITH NOT MUCH PRECIPITATION MAKING IT THIS FAR
SOUTH...BUT COOLER TEMPERATURES AND A WIND SHIFT TO THE NORTH IS
EXPECTED IF THIS SCENARIO ACTUALLY PLAYS OUT AS ADVERTISED.
INTRODUCED SOME SLIGHT CHANCE POPS ACROSS THE NORTHERN MOUNTAINS TO
ACCOUNT FOR THIS POSSIBILITY. OTHERWISE...THE WARMING TREND
CONTINUES ACROSS THE SOUTH WITH STEADY 20 TO 30 KNOT SOUTHWESTERLIES
AND CONTINUED FIRE WEATHER CONCERNS AS MIN RHS ARE EXPECTED TO DROP
INTO THE TEENS AGAIN ON WEDNESDAY AFTERNOON.

.LONG TERM...THURSDAY THROUGH MONDAY

THE GFS AND ECMWF MODELS ARE IN AGREEMENT WITH THE COLD FRONT
PUSHING SOUTH INTO CENTRAL WY THURSDAY. THE ECMWF IS STILL COOLER
AND TAKES THE FRONT WEST OF THE DIVIDE WHILE THE GFS HAS LESS
COOLING WEST OF THE DIVIDE. MADE SOME HIGH TEMP ADJUSTMENTS FROM
PREVIOUS FORECAST BUT OVERALL THE TREND IS TO GO COOLER EAST OF THE
DIVIDE AND NW WY WITH LESS COOLING IN THE SOUTH AND SOUTHWEST. THE
PRECIP CHANCE IS STILL A BIT MESSY AS THE 00Z MODELS ARE DRIER THAN
PREVIOUS RUNS. I WILL KEEP ISOLATED SHOWERS/STORMS THURS PM AND EVE.
FRIDAY LOOKS TO BE COOL EAST OF THE DIVIDE AND MILD WEST OF THE
DIVIDE AS THE FRONT SHOULD LIE ALONG THE DIVIDE. AGAIN ISOLATED
SHOWERS AND STORMS FRIDAY AFTERNOON AND EVENING. SATURDAY AND SUNDAY
WILL FEATURE ISOLATED AFTERNOON AND EVENING SHOWERS AND STORMS AS
MOISTURE WILL BE AROUND AS WELL AS THE LINGERING FRONTAL BOUNDARY.
THE ECMWF MODEL IS DRIER THAN THE GFS BOTH DAYS AS IT PUSHES THE
MOISTURE TO MAINLY SOUTHERN WY. NOT SURE THAT WILL HAPPEN SO WENT
WITH THE CONSISTENT GFS. NEXT MONDAY LOOKS DRIER BUT ISOLATED
MOUNTAIN SHOWERS/STORMS WILL STILL OCCUR OVER AND NEAR THE
MOUNTAINS. TEMPS WILL WARM A FEW DEGREES PER DAY SATURDAY THROUGH
NEXT MONDAY.

&&

.AVIATION.../12Z ISSUANCE/

A LAST IN A SERIES OF UPPER LEVEL DISTURBANCES IN NW FLOW WILL RACE
SE INTO NW WYOMING THIS MORNING AND INTO THE HIGH PLAINS LATE THIS
AFTERNOON.   AREAS OF MVFR/IFR CIGS WITH SCT -SHRA...SNOW LEVELS
NEAR 9.5KFT WITH FRQT MTN OBSCURATIONS ...WILL SPREAD ACROSS
NORTHERN WYOMING FROM YELLOWSTONE NATIONAL PARK TO A VCNTY AND NORTH
OF KCOD-KBYG LINE 09Z-15Z.  MOST OF THIS ACTIVITY WILL PUSH FROM
VCNTY OF THE BIGHORN RANGE AND EASTWARD BY EARLY AFTERNOON.  SOME OF
THIS SHOWER ACTIVITY MAY REACH AS FAR AS KCPR IN THE LATE MORNING
AND AFTERNOON.  W-NW WIND AT 15-25KT AND MAINLY SKC CONDITIONS WILL
PREVAIL ACROSS THE SOUTHERN THIRD OF THE AREA IN THE AFTERNOON.

SKC CONDITIONS WITH DIMINISHING WIND...PATCHY FOG IN THE WESTERN
VALLEYS...WILL PREVAIL MONDAY NIGHT.

&&

.FIRE WEATHER...

FIRE DANGER WILL BE RELATIVELY LOW FOR ANOTHER DAY. ISOLATED SHOWERS
AND THUNDERSTORMS WILL CONTINUE ACROSS NORTHERN WYOMING THROUGH THE
AFTERNOON. ACROSS THE SOUTH...WEST WINDS CONTINUE AT 15-25 MPH WITH
GUSTS TO 40 MPH POSSIBLE ALONG WITH MINIMUM RH VALUES ONLY DROPPING
TO 20 PERCENT AT THE LOW END. MUCH DRIER AND WARMER ON TUESDAY AND
WEDNESDAY WITH THE WINDS GUSTING OVER 30 MPH EACH AFTERNOON ACROSS
THE SOUTH...POTENTIALLY INCREASING FIRE DANGER ACROSS RAWLINS
DISPATCH AND PORTIONS OF CASPER AND CODY DISPATCH.

&&

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

&&

$$

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







000
FXUS65 KRIW 011012
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
412 AM MDT MON SEP 1 2014

.SHORT TERM...TODAY THROUGH WEDNESDAY NIGHT

THE LAST SHORT WAVE THAT COULD STIR UP MORE SHOWERS AND STORMS MOVES
THROUGH TODAY WITH EVENTUAL CLEARING WEST TO EAST AS THE MAIN TROUGH
CONTINUES TO MOVE INTO THE PLAINS. A FEW STRONGER STORMS MAY OCCUR
OVR JOHNSON COUNTY BY EARLY AFTERNOON WHERE SOME USEFUL MOISTURE
WILL STILL BE LEFTOVER...CAPE WILL BE MARGINAL BUT SHEAR WILL BE
DECENT AROUND A LEFTOVER BOUNDARY. THERE WILL ALSO BE SOME CONTINUED
BREEZY CONDITIONS AS THE SUBSIDENT SIDE OF THE TROUGH SWINGS THROUGH
AND FLOW SHIFTS TO THE NORTHWEST.

MUCH DRIER AIR MOVES IN ON TUESDAY AS FLOW TURNS MORE ZONAL. HIGH
PRESSURE BUILDING IN FROM THE SOUTH WILL ALSO BRING SOME WARMER AIR
WITH TEMPERATURES REBOUNDING BACK TO NEAR 80 EAST OF THE DIVIDE. THERE
COULD BE SOME GUSTS TO 30 MPH ACROSS THE SOUTH ON TUESDAY...WHICH
COULD LEAD TO SOME FIRE WEATHER CONCERNS IN AREAS WITH FLASHY GRASSY
FUELS.

WEDNESDAY...SOME MODEL SOLUTIONS ARE ADVERTISING ANOTHER UPPER LEVEL
TROUGH WITH SHARP COLD FRONT AND BAROCLINIC ZONE DROPPING SOUTH INTO
MONTANA...AT THIS TIME IT LOOKS LIKE WE WOULD NOT SEE MUCH FROM THE
FRONT UNTIL LATE WITH NOT MUCH PRECIPITATION MAKING IT THIS FAR
SOUTH...BUT COOLER TEMPERATURES AND A WIND SHIFT TO THE NORTH IS
EXPECTED IF THIS SCENARIO ACTUALLY PLAYS OUT AS ADVERTISED.
INTRODUCED SOME SLIGHT CHANCE POPS ACROSS THE NORTHERN MOUNTAINS TO
ACCOUNT FOR THIS POSSIBILITY. OTHERWISE...THE WARMING TREND
CONTINUES ACROSS THE SOUTH WITH STEADY 20 TO 30 KNOT SOUTHWESTERLIES
AND CONTINUED FIRE WEATHER CONCERNS AS MIN RHS ARE EXPECTED TO DROP
INTO THE TEENS AGAIN ON WEDNESDAY AFTERNOON.

.LONG TERM...THURSDAY THROUGH MONDAY

THE GFS AND ECMWF MODELS ARE IN AGREEMENT WITH THE COLD FRONT
PUSHING SOUTH INTO CENTRAL WY THURSDAY. THE ECMWF IS STILL COOLER
AND TAKES THE FRONT WEST OF THE DIVIDE WHILE THE GFS HAS LESS
COOLING WEST OF THE DIVIDE. MADE SOME HIGH TEMP ADJUSTMENTS FROM
PREVIOUS FORECAST BUT OVERALL THE TREND IS TO GO COOLER EAST OF THE
DIVIDE AND NW WY WITH LESS COOLING IN THE SOUTH AND SOUTHWEST. THE
PRECIP CHANCE IS STILL A BIT MESSY AS THE 00Z MODELS ARE DRIER THAN
PREVIOUS RUNS. I WILL KEEP ISOLATED SHOWERS/STORMS THURS PM AND EVE.
FRIDAY LOOKS TO BE COOL EAST OF THE DIVIDE AND MILD WEST OF THE
DIVIDE AS THE FRONT SHOULD LIE ALONG THE DIVIDE. AGAIN ISOLATED
SHOWERS AND STORMS FRIDAY AFTERNOON AND EVENING. SATURDAY AND SUNDAY
WILL FEATURE ISOLATED AFTERNOON AND EVENING SHOWERS AND STORMS AS
MOISTURE WILL BE AROUND AS WELL AS THE LINGERING FRONTAL BOUNDARY.
THE ECMWF MODEL IS DRIER THAN THE GFS BOTH DAYS AS IT PUSHES THE
MOISTURE TO MAINLY SOUTHERN WY. NOT SURE THAT WILL HAPPEN SO WENT
WITH THE CONSISTENT GFS. NEXT MONDAY LOOKS DRIER BUT ISOLATED
MOUNTAIN SHOWERS/STORMS WILL STILL OCCUR OVER AND NEAR THE
MOUNTAINS. TEMPS WILL WARM A FEW DEGREES PER DAY SATURDAY THROUGH
NEXT MONDAY.

&&

.AVIATION.../12Z ISSUANCE/

A LAST IN A SERIES OF UPPER LEVEL DISTURBANCES IN NW FLOW WILL RACE
SE INTO NW WYOMING THIS MORNING AND INTO THE HIGH PLAINS LATE THIS
AFTERNOON.   AREAS OF MVFR/IFR CIGS WITH SCT -SHRA...SNOW LEVELS
NEAR 9.5KFT WITH FRQT MTN OBSCURATIONS ...WILL SPREAD ACROSS
NORTHERN WYOMING FROM YELLOWSTONE NATIONAL PARK TO A VCNTY AND NORTH
OF KCOD-KBYG LINE 09Z-15Z.  MOST OF THIS ACTIVITY WILL PUSH FROM
VCNTY OF THE BIGHORN RANGE AND EASTWARD BY EARLY AFTERNOON.  SOME OF
THIS SHOWER ACTIVITY MAY REACH AS FAR AS KCPR IN THE LATE MORNING
AND AFTERNOON.  W-NW WIND AT 15-25KT AND MAINLY SKC CONDITIONS WILL
PREVAIL ACROSS THE SOUTHERN THIRD OF THE AREA IN THE AFTERNOON.

SKC CONDITIONS WITH DIMINISHING WIND...PATCHY FOG IN THE WESTERN
VALLEYS...WILL PREVAIL MONDAY NIGHT.

&&

.FIRE WEATHER...

FIRE DANGER WILL BE RELATIVELY LOW FOR ANOTHER DAY. ISOLATED SHOWERS
AND THUNDERSTORMS WILL CONTINUE ACROSS NORTHERN WYOMING THROUGH THE
AFTERNOON. ACROSS THE SOUTH...WEST WINDS CONTINUE AT 15-25 MPH WITH
GUSTS TO 40 MPH POSSIBLE ALONG WITH MINIMUM RH VALUES ONLY DROPPING
TO 20 PERCENT AT THE LOW END. MUCH DRIER AND WARMER ON TUESDAY AND
WEDNESDAY WITH THE WINDS GUSTING OVER 30 MPH EACH AFTERNOON ACROSS
THE SOUTH...POTENTIALLY INCREASING FIRE DANGER ACROSS RAWLINS
DISPATCH AND PORTIONS OF CASPER AND CODY DISPATCH.

&&

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

&&

$$

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







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000
FXUS63 KUNR 010909
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
309 AM MDT MON SEP 1 2014

.SHORT TERM...TODAY THROUGH TUESDAY NIGHT
ISSUED AT 223 AM MDT MON SEP 1 2014

CURRENT SURFACE MAP PLACES WEAK HIGH PRESSURE ACROSS WYOMING. A
FEW MID CLOUDS ACROSS THE FORECAST AREA THIS MORNING. WATER VAPOR
IMAGERY SHOWS SHORTWAVE MOVING INTO WESTERN WYOMING. A FEW
LIGHTNING STRIKES HAVE OCCURRED OVERNIGHT ALONG THE MONTANA/WYOMING
BORDER. THIS SHORTWAVE WILL MOVE ACROSS WYOMING THIS MORNING AND
INTO WESTERN SOUTH DAKOTA THIS AFTERNOON. WITH STEEP MID LEVEL
LAPSE RATES SHORTWAVE WILL BE EFFICIENT IN GENERATING
SHOWERS/THUNDERSTORMS. PRECIPITATION WILL SHIFT EAST EARLY THIS
EVENING..WITH DRY CONDITIONS OVERNIGHT. WITH CLOUDS/PRECIPITATION
TODAY...TEMPERATURES WILL BE NEAR LOW END OF GUIDANCE. STRONG
SHORTWAVE DIGS INTO THE PACIFIC NORTHWEST TUESDAY...WITH
DOWNSTREAM RIDGING ACROSS THE NORTHERN PLAINS. SUNNY AND WARMER
FOR TUESDAY.

&&

.LONG TERM...WEDNESDAY THROUGH SUNDAY
ISSUED AT 223 AM MDT MON SEP 1 2014

AN UPPER TROUGH WILL CROSS THE NRN PARTS OF THE CONUS
FROM THE PACIFIC NW INTO THE NRN PLAINS WED/THU. MODELS SHOW DECENT
AGREEMENT THAT THE BEST FORCING AND BULK OF PRECIP WILL REMAIN NORTH
OF THE CWA...THOUGH FAR NW SD COULD SEE SOME PRECIP CLIP THE AREA
WED NIGHT. IN ADDITION...SURFACE LOW WILL CROSS THE DAKOTAS WED/THU
WITH A COLD FRONT CROSSING THE REGION. ABOVE AVG TEMPS WED WILL GIVE
WAY TO COOLER THAN AVG TEMPS THUR. BEYOND THU THERE ARE SOME
DIFFERENCES IN MODELS AS A SPLIT FLOW PATTERN SETS UP FOR THE END OF
THE WEEK. THE GFS WANTS TO KEEP PRECIP OVER THE AREA AS UPPER WAVES
CROSS THROUGH THE ZONAL FLOW. THE ECM IS DRIER...SO WILL GO WITH SL
CHC POPS FOR NOW. NEAR TO BELOW AVG TEMPS ARE EXPECTED FOR THE END
OF THE WEEK...HOWEVER THERE IS A GOOD DEAL OF UNCERTAINTY WITH THIS
ATTM.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 223 AM MDT MON SEP 1 2014

SHOWERS AND ISOLATED THUNDERSTORMS WILL RETURN TODAY AS
A DISTURBANCE CROSSES THE AREA. PRECIP WILL THEN PUSH EAST OF THE
AREA BY LATE THIS EVENING. LOCAL MVFR CIGS/IFR VSBYS ARE POSSIBLE
WITH THE STRONGER SHOWERS/STORMS

&&

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

$$

SHORT TERM...79
LONG TERM...13
AVIATION...13






000
FXUS63 KUNR 010909
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
309 AM MDT MON SEP 1 2014

.SHORT TERM...TODAY THROUGH TUESDAY NIGHT
ISSUED AT 223 AM MDT MON SEP 1 2014

CURRENT SURFACE MAP PLACES WEAK HIGH PRESSURE ACROSS WYOMING. A
FEW MID CLOUDS ACROSS THE FORECAST AREA THIS MORNING. WATER VAPOR
IMAGERY SHOWS SHORTWAVE MOVING INTO WESTERN WYOMING. A FEW
LIGHTNING STRIKES HAVE OCCURRED OVERNIGHT ALONG THE MONTANA/WYOMING
BORDER. THIS SHORTWAVE WILL MOVE ACROSS WYOMING THIS MORNING AND
INTO WESTERN SOUTH DAKOTA THIS AFTERNOON. WITH STEEP MID LEVEL
LAPSE RATES SHORTWAVE WILL BE EFFICIENT IN GENERATING
SHOWERS/THUNDERSTORMS. PRECIPITATION WILL SHIFT EAST EARLY THIS
EVENING..WITH DRY CONDITIONS OVERNIGHT. WITH CLOUDS/PRECIPITATION
TODAY...TEMPERATURES WILL BE NEAR LOW END OF GUIDANCE. STRONG
SHORTWAVE DIGS INTO THE PACIFIC NORTHWEST TUESDAY...WITH
DOWNSTREAM RIDGING ACROSS THE NORTHERN PLAINS. SUNNY AND WARMER
FOR TUESDAY.

&&

.LONG TERM...WEDNESDAY THROUGH SUNDAY
ISSUED AT 223 AM MDT MON SEP 1 2014

AN UPPER TROUGH WILL CROSS THE NRN PARTS OF THE CONUS
FROM THE PACIFIC NW INTO THE NRN PLAINS WED/THU. MODELS SHOW DECENT
AGREEMENT THAT THE BEST FORCING AND BULK OF PRECIP WILL REMAIN NORTH
OF THE CWA...THOUGH FAR NW SD COULD SEE SOME PRECIP CLIP THE AREA
WED NIGHT. IN ADDITION...SURFACE LOW WILL CROSS THE DAKOTAS WED/THU
WITH A COLD FRONT CROSSING THE REGION. ABOVE AVG TEMPS WED WILL GIVE
WAY TO COOLER THAN AVG TEMPS THUR. BEYOND THU THERE ARE SOME
DIFFERENCES IN MODELS AS A SPLIT FLOW PATTERN SETS UP FOR THE END OF
THE WEEK. THE GFS WANTS TO KEEP PRECIP OVER THE AREA AS UPPER WAVES
CROSS THROUGH THE ZONAL FLOW. THE ECM IS DRIER...SO WILL GO WITH SL
CHC POPS FOR NOW. NEAR TO BELOW AVG TEMPS ARE EXPECTED FOR THE END
OF THE WEEK...HOWEVER THERE IS A GOOD DEAL OF UNCERTAINTY WITH THIS
ATTM.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 223 AM MDT MON SEP 1 2014

SHOWERS AND ISOLATED THUNDERSTORMS WILL RETURN TODAY AS
A DISTURBANCE CROSSES THE AREA. PRECIP WILL THEN PUSH EAST OF THE
AREA BY LATE THIS EVENING. LOCAL MVFR CIGS/IFR VSBYS ARE POSSIBLE
WITH THE STRONGER SHOWERS/STORMS

&&

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

$$

SHORT TERM...79
LONG TERM...13
AVIATION...13







000
FXUS65 KRIW 010556 RRA
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
1152 PM MDT SUN AUG 31 2014

.SHORT TERM...TONIGHT THROUGH MONDAY (ISSUED AT 300 PM MDT)

EXPANDING UPR LVL TROF ACROSS THE CONUS W OF THE MISSISSIPPI...W/
BASE OF TROF SWINGING EWD ACROSS WY TODAY. ANOTHER EMBEDDED SW TROF
MOVING THRU THE CNTRL FA INTO THE ERN PORTIONS OF THE STATE THIS
AFTERNOON. ANOTHER EMBEDDED SW LIES IN WAIT UPSTREAM JUST OFF THE
COAST OF OR/WA...AND WILL RACE INTO WRN/NWRN WY BY MONDAY MORNING.
AT THE SFC...GENERAL HIGH P TO THE W OF THE STATE...LOW P E WITH
FRONT/BOUNDARY BISECTING THE STATE FROM E TO SW CUTTING FROM NRN
NATRONA COUNTY...TO NRN SWEETWATER COUNTY AND W INTO SRN LINCOLN
COUNTY.

TODAY... OVERALL...MUCH COOLER CONDITIONS FROM FRONTAL
PASSAGE AND/OR SIGNIFICANT UPR LVL TEMP DROP AND CLOUD COVER.
CONTINUED  RELATIVELY STRONG GUSTY W TO WSW WINDS ACROSS THE SRN FA
SOUTH OF THE FRONT/BOUNDARY MENTIONED ABOVE...WITH GUSTY N TO NW
WINDS BEHIND THE FRONT. ANOTHER WEAKER FRONT LOOK TO BE LAYING
ACROSS MT AND WILL ENTER THE NRN AND ERN PORTION OF THE FA ON
MONDAY. ISOLATED TO SCATTERED SHOWERS AND ISOLATED THUNDER  ARE
MAKING THEIR WAY ACROSS PORTIONS OF CENTRAL AND EASTERN WY THIS
AFTERNOON...AND WILL CONTINUE AN EWD TRACK...DECREASING FROM W TO E
INTO THE EVENING. STRONGER STORMS WITH SMALL HAIL AND GUSTY WINDS
WILL BE MOST PROBABLE ERN FREMONT AND ACROSS NATRONA COUNTIES
NEAR/ALONG FRONT/BOUNDARY. CAPE AND SHEAR IN THIS AREA ARE 500-700
J/KG AND 25-30 KTS RESPECTIVELY...JUST ENOUGH TO WEAKLY ORGANIZE A
STORM OR TWO.

TONIGHT AND MONDAY...MAIN TROF PASSES E AND INTO THE GREAT PLAINS...UPR
LVL NW FLOW CONTINUES...AND THE OR/WA DISTURBANCE CONTINUES TO HEAD
THIS WAY THRU THE BACKSIDE OF THE LW TROF...ARRIVING NEAR THE WRN
BORDER BETWEEN 06 AND 09Z...THEN TRANSLATING ACROSS THE FA QUICKLY
BY EARLY AFTERNOON.  THIS WILL KEEP A NEARLY CONTINUAL CHC FOR SHRA
GOING ACROSS THE NW FA THROUGH AT LEAST MID TO LATE MORNING
MONDAY...AND ACROSS THE NRN/NERN FA INTO THE AFTERNOON. WHILE THIS
UPR LVL ENERGY WILL EXTEND WELL SOUTH AND OVR MOST OF THE
CWA...RAPID DRYING OF THE ATMOSPHERE WILL OCCUR BEHIND THE PASSAGE
OF THE MAIN TROF AXIS TONIGHT AND THROUGH MONDAY MORNING FROM W TO
E...AND THERE WILL NOT BE MUCH IN THE WAY OF MOISTURE TO ACT ON. A
FEW STRONGER STORMS MAY OCCUR OVR JOHNSON COUNTY BY EARLY AFTERNOON
WHERE SOME USEFUL MOISTURE WILL STILL BE LEFTOVER...CAPE WILL BE
MARGINAL AND SHEAR WILL BE MAXIMIZED ALONG AND NORTH OF A
CLIPPER-LIKE BOUNDARY/FRONT. SNOWFALL WILL BE POSSIBLE AGAIN ACROSS
THE NORTHERN MOUNTAINS...WITH GENERAL 1 INCH ACCUMULATIONS ABOVE
9500 FEET...AND PERHAPS A FEW AREAS ABOVE 10500 FEET RECEIVING UP TO
3 INCHES. NOT EXPECTING MUCH TO STICK TO ANY ASPHALT ROADWAYS
HOWEVER.

.LONG TERM...MONDAY NIGHT THROUGH SUNDAY

MONDAY NIGHT AS THE TROUGH CONTINUE TO MOVE EAST...HIGH PRESSURE
RIDGING WILL OCCUR OVER THE PACIFIC NORTHWEST.  THE MAIN TREND WILL
BE FOR DRYING WITH BREEZY TO WINDY CONDITIONS ACROSS THE SOUTH INTO
CENTRAL AREAS.

TUESDAY AND TUESDAY NIGHT DRY HIGH PRESSURE IS EXPECTED TO DOMINATE
THE WEATHER ACROSS THE AREA WITH INCREASING WEST TO SOUTHWEST WINDS
CENTRAL AND SOUTH WITH GENERAL WARMING. TEMPERATURES SHOULD WARM.

WEDNESDAY AND WEDNESDAY NIGHT  SOME MID LEVEL CLOUDS ARE EXPECTED TO
MOVE UP FROM THE GREAT BASIN IN THE AFTERNOON...OTHERWISE THE DRY
HIGH PRESSURE IS EXPECTED TO CONTINUE TO DOMINATE THE WEATHER WITH
CONTINUED SOUTHWEST WINDS ACROSS THE CENTRAL AND SOUTH WITH THE
WARMING TREND CONTINUING.

THURSDAY AND THURSDAY NIGHT  HIGH PRESSURE WILL SHIFT EAST WITH
INCREASING SOUTHWEST FLOW ALOFT BRINGING SOME PACIFIC MOISTURE ALOFT
OVER THE AREA.  SHOWERS ARE EXPECTED TO DEVELOP WITH ISOLATED
THUNDERSTORMS IN THE AFTERNOON...MOST NUMEROUS OVER THE WESTERN AND
CENTRAL MOUNTAINS.  INCREASED CLOUD COVER  AND A COLD FRONT MOVING
SOUTH FROM MONTANA WILL BRING COOLING.  MODELS STRONGER WITH COLD
FRONT THAN YESTERDAY WITH MORE SIGNIFICANT COOLING.

FRIDAY AND FRIDAY NIGHT  SHOWERS AND ISOLATED THUNDERSTORMS ARE
EXPECTED TO INCREASE OVER THE AREA AS PACIFIC MOISTURE INCREASES IN
SOUTHWEST FLOW ALOFT.  A COLD FRONT WILL CONTINUE TO MOVE SOUTH
INTO SOUTHERN WYOMING.  AGAIN MODELS CONTINUE TO BE STRONGER WITH
THIS COLD FRONT AND ASSOCIATED COOLING BRINGING THE COLD AIR THROUGH
THE SOUTHWEST WHILE YESTERDAY THE FRONT DID NOT MIKE IT THROUGH
CENTRAL WYOMING.

SATURDAY AND SATURDAY NIGHT SOUTHWEST FLOW ALOFT WILL REMAIN IN
PLACE OVER THE AREA WITH A STREAM OF PACIFIC MOISTURE CONTINUING TO
ADVECT INTO THE AREA SUPPORTING SCATTERED SHOWERS AND SOME ISOLATED
AFTERNOON THUNDERSTORMS.  A FRONT IS EXPECTED TO REMAIN THROUGH
SOUTHERN WYOMING WITH CONTINUED COOLING.

SUNDAY SOME DRYING IS EXPECTED IN THE WEST WITH POSSIBLE WARMING.
OVERALL LOW CONFIDENCE IN FORECAST FOR SUNDAY AS THE SPREAD IN
SOLUTIONS WITH THE EXTENDED MODELS BECOMES MORE SIGNIFICANT.

&&

.AVIATION.../06Z ISSUANCE/

A LAST IN A SERIES OF UPPER LEVEL DISTURBANCES IN NW FLOW WILL RACE
SE INTO NW WYOMING THIS MORNING AND INTO THE HIGH PLAINS LATE THIS
AFTERNOON.   AREAS OF MVFR/IFR CIGS WITH SCT -SHRA...SNOW LEVELS
NEAR 9.5KFT WITH FRQT MTN OBSCURATIONS ...WILL SPREAD ACROSS
NORTHERN WYOMING FROM YELLOWSTONE NATIONAL PARK TO A VCNTY AND NORTH
OF KCOD-KBYG LINE 09Z-15Z.  MOST OF THIS ACTIVITY WILL PUSH FROM
VCNTY OF THE BIGHORN RANGE AND EASTWARD BY EARLY AFTERNOON.  SOME OF
THIS SHOWER ACTIVITY MAY REACH AS FAR AS KCPR IN THE LATE MORNING
AND AFTERNOON.  W-NW WIND AT 15-25KT AND MAINLY SKC CONDITIONS WILL
PREVAIL ACROSS THE SOUTHERN THIRD OF THE AREA IN THE AFTERNOON.

SKC CONDITIONS WITH DIMINISHING WIND...PATCHY FOG IN THE WESTERN
VALLEYS...WILL PREVAIL MONDAY NIGHT.

&&

.FIRE WEATHER...

FIRE DANGER WILL BE RELATIVELY LOW TODAY THROUGH TONIGHT. A LARGE
UPPER LEVEL TROUGH CONTINUES TO EXPAND ACROSS THE COUNTRY TODAY WITH
ANOTHER EMBEDDED DISTURBANCE MOVING THROUGH THE TROUGH AND ACROSS
WYOMING TODAY...THEN INTO THE HIGH PLAINS BY TONIGHT. ANOTHER
DISTURBANCE WILL FOLLOW BETWEEN BETWEEN MIDNIGHT AND EARLY AFTERNOON
MONDAY...AFFECTING MAINLY THE NORTHERN FORECAST ZONES. A SURFACE
FRONT/BOUNDARY LAYS ACROSS NATRONA COUNTY AND WEST INTO SOUTHERN
FREMONT COUNTY THEN NORTHERN SWEETWATER COUNTY. ISOLATED TO
SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS WILL CONTINUE ACROSS
CENTRAL...EASTERN AND NORTHERN WYOMING THROUGH THE AFTERNOON BEFORE
BECOMING MORE ISOLATED IN NATURE FOR MOST LOCATIONS EXCEPT FOR THE
NORTHWEST WHICH WILL CONTINUE MORE SCATTERED. SNOW LEVELS WILL HOVER
BETWEEN 9-10KFT ACROSS THE NORTH. SOUTH OF THE FRONT/BOUNDARY
MENTIONED ABOVE...WEST TO WEST SOUTHWEST WINDS CONTINUE TODAY AT
15-25 MPH WITH GUSTS 35 TO 40 MPH POSSIBLE ALONG WITH MINIMUM RH
VALUES ONLY DROPPING TO 35 PERCENT AT THE LOW END. ISOLATED ERRATIC
OUTFLOW WIND GUSTS NEAR 45KTS WILL BE POSSIBLE WITH A FEW STORMS
THIS AFTERNOON.

&&

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

$$

SHORT TERM...BRAUN
LONG TERM...C.BAKER
AVIATION...AEM
FIRE WEATHER...BRAUN










000
FXUS65 KRIW 010556 RRA
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
1152 PM MDT SUN AUG 31 2014

.SHORT TERM...TONIGHT THROUGH MONDAY (ISSUED AT 300 PM MDT)

EXPANDING UPR LVL TROF ACROSS THE CONUS W OF THE MISSISSIPPI...W/
BASE OF TROF SWINGING EWD ACROSS WY TODAY. ANOTHER EMBEDDED SW TROF
MOVING THRU THE CNTRL FA INTO THE ERN PORTIONS OF THE STATE THIS
AFTERNOON. ANOTHER EMBEDDED SW LIES IN WAIT UPSTREAM JUST OFF THE
COAST OF OR/WA...AND WILL RACE INTO WRN/NWRN WY BY MONDAY MORNING.
AT THE SFC...GENERAL HIGH P TO THE W OF THE STATE...LOW P E WITH
FRONT/BOUNDARY BISECTING THE STATE FROM E TO SW CUTTING FROM NRN
NATRONA COUNTY...TO NRN SWEETWATER COUNTY AND W INTO SRN LINCOLN
COUNTY.

TODAY... OVERALL...MUCH COOLER CONDITIONS FROM FRONTAL
PASSAGE AND/OR SIGNIFICANT UPR LVL TEMP DROP AND CLOUD COVER.
CONTINUED  RELATIVELY STRONG GUSTY W TO WSW WINDS ACROSS THE SRN FA
SOUTH OF THE FRONT/BOUNDARY MENTIONED ABOVE...WITH GUSTY N TO NW
WINDS BEHIND THE FRONT. ANOTHER WEAKER FRONT LOOK TO BE LAYING
ACROSS MT AND WILL ENTER THE NRN AND ERN PORTION OF THE FA ON
MONDAY. ISOLATED TO SCATTERED SHOWERS AND ISOLATED THUNDER  ARE
MAKING THEIR WAY ACROSS PORTIONS OF CENTRAL AND EASTERN WY THIS
AFTERNOON...AND WILL CONTINUE AN EWD TRACK...DECREASING FROM W TO E
INTO THE EVENING. STRONGER STORMS WITH SMALL HAIL AND GUSTY WINDS
WILL BE MOST PROBABLE ERN FREMONT AND ACROSS NATRONA COUNTIES
NEAR/ALONG FRONT/BOUNDARY. CAPE AND SHEAR IN THIS AREA ARE 500-700
J/KG AND 25-30 KTS RESPECTIVELY...JUST ENOUGH TO WEAKLY ORGANIZE A
STORM OR TWO.

TONIGHT AND MONDAY...MAIN TROF PASSES E AND INTO THE GREAT PLAINS...UPR
LVL NW FLOW CONTINUES...AND THE OR/WA DISTURBANCE CONTINUES TO HEAD
THIS WAY THRU THE BACKSIDE OF THE LW TROF...ARRIVING NEAR THE WRN
BORDER BETWEEN 06 AND 09Z...THEN TRANSLATING ACROSS THE FA QUICKLY
BY EARLY AFTERNOON.  THIS WILL KEEP A NEARLY CONTINUAL CHC FOR SHRA
GOING ACROSS THE NW FA THROUGH AT LEAST MID TO LATE MORNING
MONDAY...AND ACROSS THE NRN/NERN FA INTO THE AFTERNOON. WHILE THIS
UPR LVL ENERGY WILL EXTEND WELL SOUTH AND OVR MOST OF THE
CWA...RAPID DRYING OF THE ATMOSPHERE WILL OCCUR BEHIND THE PASSAGE
OF THE MAIN TROF AXIS TONIGHT AND THROUGH MONDAY MORNING FROM W TO
E...AND THERE WILL NOT BE MUCH IN THE WAY OF MOISTURE TO ACT ON. A
FEW STRONGER STORMS MAY OCCUR OVR JOHNSON COUNTY BY EARLY AFTERNOON
WHERE SOME USEFUL MOISTURE WILL STILL BE LEFTOVER...CAPE WILL BE
MARGINAL AND SHEAR WILL BE MAXIMIZED ALONG AND NORTH OF A
CLIPPER-LIKE BOUNDARY/FRONT. SNOWFALL WILL BE POSSIBLE AGAIN ACROSS
THE NORTHERN MOUNTAINS...WITH GENERAL 1 INCH ACCUMULATIONS ABOVE
9500 FEET...AND PERHAPS A FEW AREAS ABOVE 10500 FEET RECEIVING UP TO
3 INCHES. NOT EXPECTING MUCH TO STICK TO ANY ASPHALT ROADWAYS
HOWEVER.

.LONG TERM...MONDAY NIGHT THROUGH SUNDAY

MONDAY NIGHT AS THE TROUGH CONTINUE TO MOVE EAST...HIGH PRESSURE
RIDGING WILL OCCUR OVER THE PACIFIC NORTHWEST.  THE MAIN TREND WILL
BE FOR DRYING WITH BREEZY TO WINDY CONDITIONS ACROSS THE SOUTH INTO
CENTRAL AREAS.

TUESDAY AND TUESDAY NIGHT DRY HIGH PRESSURE IS EXPECTED TO DOMINATE
THE WEATHER ACROSS THE AREA WITH INCREASING WEST TO SOUTHWEST WINDS
CENTRAL AND SOUTH WITH GENERAL WARMING. TEMPERATURES SHOULD WARM.

WEDNESDAY AND WEDNESDAY NIGHT  SOME MID LEVEL CLOUDS ARE EXPECTED TO
MOVE UP FROM THE GREAT BASIN IN THE AFTERNOON...OTHERWISE THE DRY
HIGH PRESSURE IS EXPECTED TO CONTINUE TO DOMINATE THE WEATHER WITH
CONTINUED SOUTHWEST WINDS ACROSS THE CENTRAL AND SOUTH WITH THE
WARMING TREND CONTINUING.

THURSDAY AND THURSDAY NIGHT  HIGH PRESSURE WILL SHIFT EAST WITH
INCREASING SOUTHWEST FLOW ALOFT BRINGING SOME PACIFIC MOISTURE ALOFT
OVER THE AREA.  SHOWERS ARE EXPECTED TO DEVELOP WITH ISOLATED
THUNDERSTORMS IN THE AFTERNOON...MOST NUMEROUS OVER THE WESTERN AND
CENTRAL MOUNTAINS.  INCREASED CLOUD COVER  AND A COLD FRONT MOVING
SOUTH FROM MONTANA WILL BRING COOLING.  MODELS STRONGER WITH COLD
FRONT THAN YESTERDAY WITH MORE SIGNIFICANT COOLING.

FRIDAY AND FRIDAY NIGHT  SHOWERS AND ISOLATED THUNDERSTORMS ARE
EXPECTED TO INCREASE OVER THE AREA AS PACIFIC MOISTURE INCREASES IN
SOUTHWEST FLOW ALOFT.  A COLD FRONT WILL CONTINUE TO MOVE SOUTH
INTO SOUTHERN WYOMING.  AGAIN MODELS CONTINUE TO BE STRONGER WITH
THIS COLD FRONT AND ASSOCIATED COOLING BRINGING THE COLD AIR THROUGH
THE SOUTHWEST WHILE YESTERDAY THE FRONT DID NOT MIKE IT THROUGH
CENTRAL WYOMING.

SATURDAY AND SATURDAY NIGHT SOUTHWEST FLOW ALOFT WILL REMAIN IN
PLACE OVER THE AREA WITH A STREAM OF PACIFIC MOISTURE CONTINUING TO
ADVECT INTO THE AREA SUPPORTING SCATTERED SHOWERS AND SOME ISOLATED
AFTERNOON THUNDERSTORMS.  A FRONT IS EXPECTED TO REMAIN THROUGH
SOUTHERN WYOMING WITH CONTINUED COOLING.

SUNDAY SOME DRYING IS EXPECTED IN THE WEST WITH POSSIBLE WARMING.
OVERALL LOW CONFIDENCE IN FORECAST FOR SUNDAY AS THE SPREAD IN
SOLUTIONS WITH THE EXTENDED MODELS BECOMES MORE SIGNIFICANT.

&&

.AVIATION.../06Z ISSUANCE/

A LAST IN A SERIES OF UPPER LEVEL DISTURBANCES IN NW FLOW WILL RACE
SE INTO NW WYOMING THIS MORNING AND INTO THE HIGH PLAINS LATE THIS
AFTERNOON.   AREAS OF MVFR/IFR CIGS WITH SCT -SHRA...SNOW LEVELS
NEAR 9.5KFT WITH FRQT MTN OBSCURATIONS ...WILL SPREAD ACROSS
NORTHERN WYOMING FROM YELLOWSTONE NATIONAL PARK TO A VCNTY AND NORTH
OF KCOD-KBYG LINE 09Z-15Z.  MOST OF THIS ACTIVITY WILL PUSH FROM
VCNTY OF THE BIGHORN RANGE AND EASTWARD BY EARLY AFTERNOON.  SOME OF
THIS SHOWER ACTIVITY MAY REACH AS FAR AS KCPR IN THE LATE MORNING
AND AFTERNOON.  W-NW WIND AT 15-25KT AND MAINLY SKC CONDITIONS WILL
PREVAIL ACROSS THE SOUTHERN THIRD OF THE AREA IN THE AFTERNOON.

SKC CONDITIONS WITH DIMINISHING WIND...PATCHY FOG IN THE WESTERN
VALLEYS...WILL PREVAIL MONDAY NIGHT.

&&

.FIRE WEATHER...

FIRE DANGER WILL BE RELATIVELY LOW TODAY THROUGH TONIGHT. A LARGE
UPPER LEVEL TROUGH CONTINUES TO EXPAND ACROSS THE COUNTRY TODAY WITH
ANOTHER EMBEDDED DISTURBANCE MOVING THROUGH THE TROUGH AND ACROSS
WYOMING TODAY...THEN INTO THE HIGH PLAINS BY TONIGHT. ANOTHER
DISTURBANCE WILL FOLLOW BETWEEN BETWEEN MIDNIGHT AND EARLY AFTERNOON
MONDAY...AFFECTING MAINLY THE NORTHERN FORECAST ZONES. A SURFACE
FRONT/BOUNDARY LAYS ACROSS NATRONA COUNTY AND WEST INTO SOUTHERN
FREMONT COUNTY THEN NORTHERN SWEETWATER COUNTY. ISOLATED TO
SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS WILL CONTINUE ACROSS
CENTRAL...EASTERN AND NORTHERN WYOMING THROUGH THE AFTERNOON BEFORE
BECOMING MORE ISOLATED IN NATURE FOR MOST LOCATIONS EXCEPT FOR THE
NORTHWEST WHICH WILL CONTINUE MORE SCATTERED. SNOW LEVELS WILL HOVER
BETWEEN 9-10KFT ACROSS THE NORTH. SOUTH OF THE FRONT/BOUNDARY
MENTIONED ABOVE...WEST TO WEST SOUTHWEST WINDS CONTINUE TODAY AT
15-25 MPH WITH GUSTS 35 TO 40 MPH POSSIBLE ALONG WITH MINIMUM RH
VALUES ONLY DROPPING TO 35 PERCENT AT THE LOW END. ISOLATED ERRATIC
OUTFLOW WIND GUSTS NEAR 45KTS WILL BE POSSIBLE WITH A FEW STORMS
THIS AFTERNOON.

&&

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

$$

SHORT TERM...BRAUN
LONG TERM...C.BAKER
AVIATION...AEM
FIRE WEATHER...BRAUN









000
FXUS65 KRIW 010556
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
1152 PM MDT SUN AUG 31 2014

.SHORT TERM...TONIGHT THROUGH MONDAY (ISSUED AT 300 PM MDT)

EXPANDING UPR LVL TROF ACROSS THE CONUS W OF THE MISSISSIPPI...W/
BASE OF TROF SWINGING EWD ACROSS WY TODAY. ANOTHER EMBEDDED SW TROF
MOVING THRU THE CNTRL FA INTO THE ERN PORTIONS OF THE STATE THIS
AFTERNOON. ANOTHER EMBEDDED SW LIES IN WAIT UPSTREAM JUST OFF THE
COAST OF OR/WA...AND WILL RACE INTO WRN/NWRN WY BY MONDAY MORNING.
AT THE SFC...GENERAL HIGH P TO THE W OF THE STATE...LOW P E WITH
FRONT/BOUNDARY BISECTING THE STATE FROM E TO SW CUTTING FROM NRN
NATRONA COUNTY...TO NRN SWEETWATER COUNTY AND W INTO SRN LINCOLN
COUNTY.

TODAY... OVERALL...MUCH COOLER CONDITIONS FROM FRONTAL
PASSAGE AND/OR SIGNIFICANT UPR LVL TEMP DROP AND CLOUD COVER.
CONTINUED  RELATIVELY STRONG GUSTY W TO WSW WINDS ACROSS THE SRN FA
SOUTH OF THE FRONT/BOUNDARY MENTIONED ABOVE...WITH GUSTY N TO NW
WINDS BEHIND THE FRONT. ANOTHER WEAKER FRONT LOOK TO BE LAYING
ACROSS MT AND WILL ENTER THE NRN AND ERN PORTION OF THE FA ON
MONDAY. ISOLATED TO SCATTERED SHOWERS AND ISOLATED THUNDER  ARE
MAKING THEIR WAY ACROSS PORTIONS OF CENTRAL AND EASTERN WY THIS
AFTERNOON...AND WILL CONTINUE AN EWD TRACK...DECREASING FROM W TO E
INTO THE EVENING. STRONGER STORMS WITH SMALL HAIL AND GUSTY WINDS
WILL BE MOST PROBABLE ERN FREMONT AND ACROSS NATRONA COUNTIES
NEAR/ALONG FRONT/BOUNDARY. CAPE AND SHEAR IN THIS AREA ARE 500-700
J/KG AND 25-30 KTS RESPECTIVELY...JUST ENOUGH TO WEAKLY ORGANIZE A
STORM OR TWO.

TONIGHT AND MONDAY...MAIN TROF PASSES E AND INTO THE GREAT PLAINS...UPR
LVL NW FLOW CONTINUES...AND THE OR/WA DISTURBANCE CONTINUES TO HEAD
THIS WAY THRU THE BACKSIDE OF THE LW TROF...ARRIVING NEAR THE WRN
BORDER BETWEEN 06 AND 09Z...THEN TRANSLATING ACROSS THE FA QUICKLY
BY EARLY AFTERNOON.  THIS WILL KEEP A NEARLY CONTINUAL CHC FOR SHRA
GOING ACROSS THE NW FA THROUGH AT LEAST MID TO LATE MORNING
MONDAY...AND ACROSS THE NRN/NERN FA INTO THE AFTERNOON. WHILE THIS
UPR LVL ENERGY WILL EXTEND WELL SOUTH AND OVR MOST OF THE
CWA...RAPID DRYING OF THE ATMOSPHERE WILL OCCUR BEHIND THE PASSAGE
OF THE MAIN TROF AXIS TONIGHT AND THROUGH MONDAY MORNING FROM W TO
E...AND THERE WILL NOT BE MUCH IN THE WAY OF MOISTURE TO ACT ON. A
FEW STRONGER STORMS MAY OCCUR OVR JOHNSON COUNTY BY EARLY AFTERNOON
WHERE SOME USEFUL MOISTURE WILL STILL BE LEFTOVER...CAPE WILL BE
MARGINAL AND SHEAR WILL BE MAXIMIZED ALONG AND NORTH OF A
CLIPPER-LIKE BOUNDARY/FRONT. SNOWFALL WILL BE POSSIBLE AGAIN ACROSS
THE NORTHERN MOUNTAINS...WITH GENERAL 1 INCH ACCUMULATIONS ABOVE
9500 FEET...AND PERHAPS A FEW AREAS ABOVE 10500 FEET RECEIVING UP TO
3 INCHES. NOT EXPECTING MUCH TO STICK TO ANY ASPHALT ROADWAYS
HOWEVER.

.LONG TERM...MONDAY NIGHT THROUGH SUNDAY

MONDAY NIGHT AS THE TROUGH CONTINUE TO MOVE EAST...HIGH PRESSURE
RIDGING WILL OCCUR OVER THE PACIFIC NORTHWEST.  THE MAIN TREND WILL
BE FOR DRYING WITH BREEZY TO WINDY CONDITIONS ACROSS THE SOUTH INTO
CENTRAL AREAS.

TUESDAY AND TUESDAY NIGHT DRY HIGH PRESSURE IS EXPECTED TO DOMINATE
THE WEATHER ACROSS THE AREA WITH INCREASING WEST TO SOUTHWEST WINDS
CENTRAL AND SOUTH WITH GENERAL WARMING. TEMPERATURES SHOULD WARM.

WEDNESDAY AND WEDNESDAY NIGHT  SOME MID LEVEL CLOUDS ARE EXPECTED TO
MOVE UP FROM THE GREAT BASIN IN THE AFTERNOON...OTHERWISE THE DRY
HIGH PRESSURE IS EXPECTED TO CONTINUE TO DOMINATE THE WEATHER WITH
CONTINUED SOUTHWEST WINDS ACROSS THE CENTRAL AND SOUTH WITH THE
WARMING TREND CONTINUING.

THURSDAY AND THURSDAY NIGHT  HIGH PRESSURE WILL SHIFT EAST WITH
INCREASING SOUTHWEST FLOW ALOFT BRINGING SOME PACIFIC MOISTURE ALOFT
OVER THE AREA.  SHOWERS ARE EXPECTED TO DEVELOP WITH ISOLATED
THUNDERSTORMS IN THE AFTERNOON...MOST NUMEROUS OVER THE WESTERN AND
CENTRAL MOUNTAINS.  INCREASED CLOUD COVER  AND A COLD FRONT MOVING
SOUTH FROM MONTANA WILL BRING COOLING.  MODELS STRONGER WITH COLD
FRONT THAN YESTERDAY WITH MORE SIGNIFICANT COOLING.

FRIDAY AND FRIDAY NIGHT  SHOWERS AND ISOLATED THUNDERSTORMS ARE
EXPECTED TO INCREASE OVER THE AREA AS PACIFIC MOISTURE INCREASES IN
SOUTHWEST FLOW ALOFT.  A COLD FRONT WILL CONTINUE TO MOVE SOUTH
INTO SOUTHERN WYOMING.  AGAIN MODELS CONTINUE TO BE STRONGER WITH
THIS COLD FRONT AND ASSOCIATED COOLING BRINGING THE COLD AIR THROUGH
THE SOUTHWEST WHILE YESTERDAY THE FRONT DID NOT MIKE IT THROUGH
CENTRAL WYOMING.

SATURDAY AND SATURDAY NIGHT SOUTHWEST FLOW ALOFT WILL REMAIN IN
PLACE OVER THE AREA WITH A STREAM OF PACIFIC MOISTURE CONTINUING TO
ADVECT INTO THE AREA SUPPORTING SCATTERED SHOWERS AND SOME ISOLATED
AFTERNOON THUNDERSTORMS.  A FRONT IS EXPECTED TO REMAIN THROUGH
SOUTHERN WYOMING WITH CONTINUED COOLING.

SUNDAY SOME DRYING IS EXPECTED IN THE WEST WITH POSSIBLE WARMING.
OVERALL LOW CONFIDENCE IN FORECAST FOR SUNDAY AS THE SPREAD IN
SOLUTIONS WITH THE EXTENDED MODELS BECOMES MORE SIGNIFICANT.

&&

.AVIATION.../06Z ISSUANCE/

A LAST IN A SERIES OF UPPER LEVEL DISTURBANCES IN NW FLOW WILL RACE
SE INTO NW WYOMING THIS MORNING AND INTO THE HIGH PLAINS LATE THIS
AFTERNOON.   AREAS OF MVFR/IFR CIGS WITH SCT -SHRA...SNOW LEVELS
NEAR 9.5KFT WITH FRQT MTN OBSCURATIONS ...WILL SPREAD ACROSS
NORTHERN WYOMING FROM YELLOWSTONE NATIONAL PARK TO A VCNTY AND NORTH
OF KCOD-KBYG LINE 09Z-15Z.  MOST OF THIS ACTIVITY WILL PUSH FROM
VCNTY OF THE BIGHORN RANGE AND EASTWARD BY EARLY AFTERNOON.  SOME OF
THIS SHOWER ACTIVITY MAY REACH AS FAR AS KCPR IN THE LATE MORNING
AND AFTERNOON.  W-NW WIND AT 15-25KT AND MAINLY SKC CONDITIONS WILL
PREVAIL ACROSS THE SOUTHERN THIRD OF THE AREA IN THE AFTERNOON.

SKC CONDITIONS WITH DIMINISHING WIND...PATCHY FOG IN THE WESTERN
VALLEYS...WILL PREVAIL MONDAY NIGHT.

&&

.FIRE WEATHER...

FIRE DANGER WILL BE RELATIVELY LOW TODAY THROUGH TONIGHT. A LARGE
UPPER LEVEL TROUGH CONTINUES TO EXPAND ACROSS THE COUNTRY TODAY WITH
ANOTHER EMBEDDED DISTURBANCE MOVING THROUGH THE TROUGH AND ACROSS
WYOMING TODAY...THEN INTO THE HIGH PLAINS BY TONIGHT. ANOTHER
DISTURBANCE WILL FOLLOW BETWEEN BETWEEN MIDNIGHT AND EARLY AFTERNOON
MONDAY...AFFECTING MAINLY THE NORTHERN FORECAST ZONES. A SURFACE
FRONT/BOUNDARY LAYS ACROSS NATRONA COUNTY AND WEST INTO SOUTHERN
FREMONT COUNTY THEN NORTHERN SWEETWATER COUNTY. ISOLATED TO
SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS WILL CONTINUE ACROSS
CENTRAL...EASTERN AND NORTHERN WYOMING THROUGH THE AFTERNOON BEFORE
BECOMING MORE ISOLATED IN NATURE FOR MOST LOCATIONS EXCEPT FOR THE
NORTHWEST WHICH WILL CONTINUE MORE SCATTERED. SNOW LEVELS WILL HOVER
BETWEEN 9-10KFT ACROSS THE NORTH. SOUTH OF THE FRONT/BOUNDARY
MENTIONED ABOVE...WEST TO WEST SOUTHWEST WINDS CONTINUE TODAY AT
15-25 MPH WITH GUSTS 35 TO 40 MPH POSSIBLE ALONG WITH MINIMUM RH
VALUES ONLY DROPPING TO 35 PERCENT AT THE LOW END. ISOLATED ERRATIC
OUTFLOW WIND GUSTS NEAR 45KTS WILL BE POSSIBLE WITH A FEW STORMS
THIS AFTERNOON.

&&

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

$$

SHORT TERM...BRAUN
LONG TERM...C.BAKER
AVIATION...BRAUN
FIRE WEATHER...BRAUN








000
FXUS65 KRIW 010556
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
1152 PM MDT SUN AUG 31 2014

.SHORT TERM...TONIGHT THROUGH MONDAY (ISSUED AT 300 PM MDT)

EXPANDING UPR LVL TROF ACROSS THE CONUS W OF THE MISSISSIPPI...W/
BASE OF TROF SWINGING EWD ACROSS WY TODAY. ANOTHER EMBEDDED SW TROF
MOVING THRU THE CNTRL FA INTO THE ERN PORTIONS OF THE STATE THIS
AFTERNOON. ANOTHER EMBEDDED SW LIES IN WAIT UPSTREAM JUST OFF THE
COAST OF OR/WA...AND WILL RACE INTO WRN/NWRN WY BY MONDAY MORNING.
AT THE SFC...GENERAL HIGH P TO THE W OF THE STATE...LOW P E WITH
FRONT/BOUNDARY BISECTING THE STATE FROM E TO SW CUTTING FROM NRN
NATRONA COUNTY...TO NRN SWEETWATER COUNTY AND W INTO SRN LINCOLN
COUNTY.

TODAY... OVERALL...MUCH COOLER CONDITIONS FROM FRONTAL
PASSAGE AND/OR SIGNIFICANT UPR LVL TEMP DROP AND CLOUD COVER.
CONTINUED  RELATIVELY STRONG GUSTY W TO WSW WINDS ACROSS THE SRN FA
SOUTH OF THE FRONT/BOUNDARY MENTIONED ABOVE...WITH GUSTY N TO NW
WINDS BEHIND THE FRONT. ANOTHER WEAKER FRONT LOOK TO BE LAYING
ACROSS MT AND WILL ENTER THE NRN AND ERN PORTION OF THE FA ON
MONDAY. ISOLATED TO SCATTERED SHOWERS AND ISOLATED THUNDER  ARE
MAKING THEIR WAY ACROSS PORTIONS OF CENTRAL AND EASTERN WY THIS
AFTERNOON...AND WILL CONTINUE AN EWD TRACK...DECREASING FROM W TO E
INTO THE EVENING. STRONGER STORMS WITH SMALL HAIL AND GUSTY WINDS
WILL BE MOST PROBABLE ERN FREMONT AND ACROSS NATRONA COUNTIES
NEAR/ALONG FRONT/BOUNDARY. CAPE AND SHEAR IN THIS AREA ARE 500-700
J/KG AND 25-30 KTS RESPECTIVELY...JUST ENOUGH TO WEAKLY ORGANIZE A
STORM OR TWO.

TONIGHT AND MONDAY...MAIN TROF PASSES E AND INTO THE GREAT PLAINS...UPR
LVL NW FLOW CONTINUES...AND THE OR/WA DISTURBANCE CONTINUES TO HEAD
THIS WAY THRU THE BACKSIDE OF THE LW TROF...ARRIVING NEAR THE WRN
BORDER BETWEEN 06 AND 09Z...THEN TRANSLATING ACROSS THE FA QUICKLY
BY EARLY AFTERNOON.  THIS WILL KEEP A NEARLY CONTINUAL CHC FOR SHRA
GOING ACROSS THE NW FA THROUGH AT LEAST MID TO LATE MORNING
MONDAY...AND ACROSS THE NRN/NERN FA INTO THE AFTERNOON. WHILE THIS
UPR LVL ENERGY WILL EXTEND WELL SOUTH AND OVR MOST OF THE
CWA...RAPID DRYING OF THE ATMOSPHERE WILL OCCUR BEHIND THE PASSAGE
OF THE MAIN TROF AXIS TONIGHT AND THROUGH MONDAY MORNING FROM W TO
E...AND THERE WILL NOT BE MUCH IN THE WAY OF MOISTURE TO ACT ON. A
FEW STRONGER STORMS MAY OCCUR OVR JOHNSON COUNTY BY EARLY AFTERNOON
WHERE SOME USEFUL MOISTURE WILL STILL BE LEFTOVER...CAPE WILL BE
MARGINAL AND SHEAR WILL BE MAXIMIZED ALONG AND NORTH OF A
CLIPPER-LIKE BOUNDARY/FRONT. SNOWFALL WILL BE POSSIBLE AGAIN ACROSS
THE NORTHERN MOUNTAINS...WITH GENERAL 1 INCH ACCUMULATIONS ABOVE
9500 FEET...AND PERHAPS A FEW AREAS ABOVE 10500 FEET RECEIVING UP TO
3 INCHES. NOT EXPECTING MUCH TO STICK TO ANY ASPHALT ROADWAYS
HOWEVER.

.LONG TERM...MONDAY NIGHT THROUGH SUNDAY

MONDAY NIGHT AS THE TROUGH CONTINUE TO MOVE EAST...HIGH PRESSURE
RIDGING WILL OCCUR OVER THE PACIFIC NORTHWEST.  THE MAIN TREND WILL
BE FOR DRYING WITH BREEZY TO WINDY CONDITIONS ACROSS THE SOUTH INTO
CENTRAL AREAS.

TUESDAY AND TUESDAY NIGHT DRY HIGH PRESSURE IS EXPECTED TO DOMINATE
THE WEATHER ACROSS THE AREA WITH INCREASING WEST TO SOUTHWEST WINDS
CENTRAL AND SOUTH WITH GENERAL WARMING. TEMPERATURES SHOULD WARM.

WEDNESDAY AND WEDNESDAY NIGHT  SOME MID LEVEL CLOUDS ARE EXPECTED TO
MOVE UP FROM THE GREAT BASIN IN THE AFTERNOON...OTHERWISE THE DRY
HIGH PRESSURE IS EXPECTED TO CONTINUE TO DOMINATE THE WEATHER WITH
CONTINUED SOUTHWEST WINDS ACROSS THE CENTRAL AND SOUTH WITH THE
WARMING TREND CONTINUING.

THURSDAY AND THURSDAY NIGHT  HIGH PRESSURE WILL SHIFT EAST WITH
INCREASING SOUTHWEST FLOW ALOFT BRINGING SOME PACIFIC MOISTURE ALOFT
OVER THE AREA.  SHOWERS ARE EXPECTED TO DEVELOP WITH ISOLATED
THUNDERSTORMS IN THE AFTERNOON...MOST NUMEROUS OVER THE WESTERN AND
CENTRAL MOUNTAINS.  INCREASED CLOUD COVER  AND A COLD FRONT MOVING
SOUTH FROM MONTANA WILL BRING COOLING.  MODELS STRONGER WITH COLD
FRONT THAN YESTERDAY WITH MORE SIGNIFICANT COOLING.

FRIDAY AND FRIDAY NIGHT  SHOWERS AND ISOLATED THUNDERSTORMS ARE
EXPECTED TO INCREASE OVER THE AREA AS PACIFIC MOISTURE INCREASES IN
SOUTHWEST FLOW ALOFT.  A COLD FRONT WILL CONTINUE TO MOVE SOUTH
INTO SOUTHERN WYOMING.  AGAIN MODELS CONTINUE TO BE STRONGER WITH
THIS COLD FRONT AND ASSOCIATED COOLING BRINGING THE COLD AIR THROUGH
THE SOUTHWEST WHILE YESTERDAY THE FRONT DID NOT MIKE IT THROUGH
CENTRAL WYOMING.

SATURDAY AND SATURDAY NIGHT SOUTHWEST FLOW ALOFT WILL REMAIN IN
PLACE OVER THE AREA WITH A STREAM OF PACIFIC MOISTURE CONTINUING TO
ADVECT INTO THE AREA SUPPORTING SCATTERED SHOWERS AND SOME ISOLATED
AFTERNOON THUNDERSTORMS.  A FRONT IS EXPECTED TO REMAIN THROUGH
SOUTHERN WYOMING WITH CONTINUED COOLING.

SUNDAY SOME DRYING IS EXPECTED IN THE WEST WITH POSSIBLE WARMING.
OVERALL LOW CONFIDENCE IN FORECAST FOR SUNDAY AS THE SPREAD IN
SOLUTIONS WITH THE EXTENDED MODELS BECOMES MORE SIGNIFICANT.

&&

.AVIATION.../06Z ISSUANCE/

A LAST IN A SERIES OF UPPER LEVEL DISTURBANCES IN NW FLOW WILL RACE
SE INTO NW WYOMING THIS MORNING AND INTO THE HIGH PLAINS LATE THIS
AFTERNOON.   AREAS OF MVFR/IFR CIGS WITH SCT -SHRA...SNOW LEVELS
NEAR 9.5KFT WITH FRQT MTN OBSCURATIONS ...WILL SPREAD ACROSS
NORTHERN WYOMING FROM YELLOWSTONE NATIONAL PARK TO A VCNTY AND NORTH
OF KCOD-KBYG LINE 09Z-15Z.  MOST OF THIS ACTIVITY WILL PUSH FROM
VCNTY OF THE BIGHORN RANGE AND EASTWARD BY EARLY AFTERNOON.  SOME OF
THIS SHOWER ACTIVITY MAY REACH AS FAR AS KCPR IN THE LATE MORNING
AND AFTERNOON.  W-NW WIND AT 15-25KT AND MAINLY SKC CONDITIONS WILL
PREVAIL ACROSS THE SOUTHERN THIRD OF THE AREA IN THE AFTERNOON.

SKC CONDITIONS WITH DIMINISHING WIND...PATCHY FOG IN THE WESTERN
VALLEYS...WILL PREVAIL MONDAY NIGHT.

&&

.FIRE WEATHER...

FIRE DANGER WILL BE RELATIVELY LOW TODAY THROUGH TONIGHT. A LARGE
UPPER LEVEL TROUGH CONTINUES TO EXPAND ACROSS THE COUNTRY TODAY WITH
ANOTHER EMBEDDED DISTURBANCE MOVING THROUGH THE TROUGH AND ACROSS
WYOMING TODAY...THEN INTO THE HIGH PLAINS BY TONIGHT. ANOTHER
DISTURBANCE WILL FOLLOW BETWEEN BETWEEN MIDNIGHT AND EARLY AFTERNOON
MONDAY...AFFECTING MAINLY THE NORTHERN FORECAST ZONES. A SURFACE
FRONT/BOUNDARY LAYS ACROSS NATRONA COUNTY AND WEST INTO SOUTHERN
FREMONT COUNTY THEN NORTHERN SWEETWATER COUNTY. ISOLATED TO
SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS WILL CONTINUE ACROSS
CENTRAL...EASTERN AND NORTHERN WYOMING THROUGH THE AFTERNOON BEFORE
BECOMING MORE ISOLATED IN NATURE FOR MOST LOCATIONS EXCEPT FOR THE
NORTHWEST WHICH WILL CONTINUE MORE SCATTERED. SNOW LEVELS WILL HOVER
BETWEEN 9-10KFT ACROSS THE NORTH. SOUTH OF THE FRONT/BOUNDARY
MENTIONED ABOVE...WEST TO WEST SOUTHWEST WINDS CONTINUE TODAY AT
15-25 MPH WITH GUSTS 35 TO 40 MPH POSSIBLE ALONG WITH MINIMUM RH
VALUES ONLY DROPPING TO 35 PERCENT AT THE LOW END. ISOLATED ERRATIC
OUTFLOW WIND GUSTS NEAR 45KTS WILL BE POSSIBLE WITH A FEW STORMS
THIS AFTERNOON.

&&

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

$$

SHORT TERM...BRAUN
LONG TERM...C.BAKER
AVIATION...BRAUN
FIRE WEATHER...BRAUN








000
FXUS65 KRIW 010556
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
1152 PM MDT SUN AUG 31 2014

.SHORT TERM...TONIGHT THROUGH MONDAY (ISSUED AT 300 PM MDT)

EXPANDING UPR LVL TROF ACROSS THE CONUS W OF THE MISSISSIPPI...W/
BASE OF TROF SWINGING EWD ACROSS WY TODAY. ANOTHER EMBEDDED SW TROF
MOVING THRU THE CNTRL FA INTO THE ERN PORTIONS OF THE STATE THIS
AFTERNOON. ANOTHER EMBEDDED SW LIES IN WAIT UPSTREAM JUST OFF THE
COAST OF OR/WA...AND WILL RACE INTO WRN/NWRN WY BY MONDAY MORNING.
AT THE SFC...GENERAL HIGH P TO THE W OF THE STATE...LOW P E WITH
FRONT/BOUNDARY BISECTING THE STATE FROM E TO SW CUTTING FROM NRN
NATRONA COUNTY...TO NRN SWEETWATER COUNTY AND W INTO SRN LINCOLN
COUNTY.

TODAY... OVERALL...MUCH COOLER CONDITIONS FROM FRONTAL
PASSAGE AND/OR SIGNIFICANT UPR LVL TEMP DROP AND CLOUD COVER.
CONTINUED  RELATIVELY STRONG GUSTY W TO WSW WINDS ACROSS THE SRN FA
SOUTH OF THE FRONT/BOUNDARY MENTIONED ABOVE...WITH GUSTY N TO NW
WINDS BEHIND THE FRONT. ANOTHER WEAKER FRONT LOOK TO BE LAYING
ACROSS MT AND WILL ENTER THE NRN AND ERN PORTION OF THE FA ON
MONDAY. ISOLATED TO SCATTERED SHOWERS AND ISOLATED THUNDER  ARE
MAKING THEIR WAY ACROSS PORTIONS OF CENTRAL AND EASTERN WY THIS
AFTERNOON...AND WILL CONTINUE AN EWD TRACK...DECREASING FROM W TO E
INTO THE EVENING. STRONGER STORMS WITH SMALL HAIL AND GUSTY WINDS
WILL BE MOST PROBABLE ERN FREMONT AND ACROSS NATRONA COUNTIES
NEAR/ALONG FRONT/BOUNDARY. CAPE AND SHEAR IN THIS AREA ARE 500-700
J/KG AND 25-30 KTS RESPECTIVELY...JUST ENOUGH TO WEAKLY ORGANIZE A
STORM OR TWO.

TONIGHT AND MONDAY...MAIN TROF PASSES E AND INTO THE GREAT PLAINS...UPR
LVL NW FLOW CONTINUES...AND THE OR/WA DISTURBANCE CONTINUES TO HEAD
THIS WAY THRU THE BACKSIDE OF THE LW TROF...ARRIVING NEAR THE WRN
BORDER BETWEEN 06 AND 09Z...THEN TRANSLATING ACROSS THE FA QUICKLY
BY EARLY AFTERNOON.  THIS WILL KEEP A NEARLY CONTINUAL CHC FOR SHRA
GOING ACROSS THE NW FA THROUGH AT LEAST MID TO LATE MORNING
MONDAY...AND ACROSS THE NRN/NERN FA INTO THE AFTERNOON. WHILE THIS
UPR LVL ENERGY WILL EXTEND WELL SOUTH AND OVR MOST OF THE
CWA...RAPID DRYING OF THE ATMOSPHERE WILL OCCUR BEHIND THE PASSAGE
OF THE MAIN TROF AXIS TONIGHT AND THROUGH MONDAY MORNING FROM W TO
E...AND THERE WILL NOT BE MUCH IN THE WAY OF MOISTURE TO ACT ON. A
FEW STRONGER STORMS MAY OCCUR OVR JOHNSON COUNTY BY EARLY AFTERNOON
WHERE SOME USEFUL MOISTURE WILL STILL BE LEFTOVER...CAPE WILL BE
MARGINAL AND SHEAR WILL BE MAXIMIZED ALONG AND NORTH OF A
CLIPPER-LIKE BOUNDARY/FRONT. SNOWFALL WILL BE POSSIBLE AGAIN ACROSS
THE NORTHERN MOUNTAINS...WITH GENERAL 1 INCH ACCUMULATIONS ABOVE
9500 FEET...AND PERHAPS A FEW AREAS ABOVE 10500 FEET RECEIVING UP TO
3 INCHES. NOT EXPECTING MUCH TO STICK TO ANY ASPHALT ROADWAYS
HOWEVER.

.LONG TERM...MONDAY NIGHT THROUGH SUNDAY

MONDAY NIGHT AS THE TROUGH CONTINUE TO MOVE EAST...HIGH PRESSURE
RIDGING WILL OCCUR OVER THE PACIFIC NORTHWEST.  THE MAIN TREND WILL
BE FOR DRYING WITH BREEZY TO WINDY CONDITIONS ACROSS THE SOUTH INTO
CENTRAL AREAS.

TUESDAY AND TUESDAY NIGHT DRY HIGH PRESSURE IS EXPECTED TO DOMINATE
THE WEATHER ACROSS THE AREA WITH INCREASING WEST TO SOUTHWEST WINDS
CENTRAL AND SOUTH WITH GENERAL WARMING. TEMPERATURES SHOULD WARM.

WEDNESDAY AND WEDNESDAY NIGHT  SOME MID LEVEL CLOUDS ARE EXPECTED TO
MOVE UP FROM THE GREAT BASIN IN THE AFTERNOON...OTHERWISE THE DRY
HIGH PRESSURE IS EXPECTED TO CONTINUE TO DOMINATE THE WEATHER WITH
CONTINUED SOUTHWEST WINDS ACROSS THE CENTRAL AND SOUTH WITH THE
WARMING TREND CONTINUING.

THURSDAY AND THURSDAY NIGHT  HIGH PRESSURE WILL SHIFT EAST WITH
INCREASING SOUTHWEST FLOW ALOFT BRINGING SOME PACIFIC MOISTURE ALOFT
OVER THE AREA.  SHOWERS ARE EXPECTED TO DEVELOP WITH ISOLATED
THUNDERSTORMS IN THE AFTERNOON...MOST NUMEROUS OVER THE WESTERN AND
CENTRAL MOUNTAINS.  INCREASED CLOUD COVER  AND A COLD FRONT MOVING
SOUTH FROM MONTANA WILL BRING COOLING.  MODELS STRONGER WITH COLD
FRONT THAN YESTERDAY WITH MORE SIGNIFICANT COOLING.

FRIDAY AND FRIDAY NIGHT  SHOWERS AND ISOLATED THUNDERSTORMS ARE
EXPECTED TO INCREASE OVER THE AREA AS PACIFIC MOISTURE INCREASES IN
SOUTHWEST FLOW ALOFT.  A COLD FRONT WILL CONTINUE TO MOVE SOUTH
INTO SOUTHERN WYOMING.  AGAIN MODELS CONTINUE TO BE STRONGER WITH
THIS COLD FRONT AND ASSOCIATED COOLING BRINGING THE COLD AIR THROUGH
THE SOUTHWEST WHILE YESTERDAY THE FRONT DID NOT MIKE IT THROUGH
CENTRAL WYOMING.

SATURDAY AND SATURDAY NIGHT SOUTHWEST FLOW ALOFT WILL REMAIN IN
PLACE OVER THE AREA WITH A STREAM OF PACIFIC MOISTURE CONTINUING TO
ADVECT INTO THE AREA SUPPORTING SCATTERED SHOWERS AND SOME ISOLATED
AFTERNOON THUNDERSTORMS.  A FRONT IS EXPECTED TO REMAIN THROUGH
SOUTHERN WYOMING WITH CONTINUED COOLING.

SUNDAY SOME DRYING IS EXPECTED IN THE WEST WITH POSSIBLE WARMING.
OVERALL LOW CONFIDENCE IN FORECAST FOR SUNDAY AS THE SPREAD IN
SOLUTIONS WITH THE EXTENDED MODELS BECOMES MORE SIGNIFICANT.

&&

.AVIATION.../06Z ISSUANCE/

A LAST IN A SERIES OF UPPER LEVEL DISTURBANCES IN NW FLOW WILL RACE
SE INTO NW WYOMING THIS MORNING AND INTO THE HIGH PLAINS LATE THIS
AFTERNOON.   AREAS OF MVFR/IFR CIGS WITH SCT -SHRA...SNOW LEVELS
NEAR 9.5KFT WITH FRQT MTN OBSCURATIONS ...WILL SPREAD ACROSS
NORTHERN WYOMING FROM YELLOWSTONE NATIONAL PARK TO A VCNTY AND NORTH
OF KCOD-KBYG LINE 09Z-15Z.  MOST OF THIS ACTIVITY WILL PUSH FROM
VCNTY OF THE BIGHORN RANGE AND EASTWARD BY EARLY AFTERNOON.  SOME OF
THIS SHOWER ACTIVITY MAY REACH AS FAR AS KCPR IN THE LATE MORNING
AND AFTERNOON.  W-NW WIND AT 15-25KT AND MAINLY SKC CONDITIONS WILL
PREVAIL ACROSS THE SOUTHERN THIRD OF THE AREA IN THE AFTERNOON.

SKC CONDITIONS WITH DIMINISHING WIND...PATCHY FOG IN THE WESTERN
VALLEYS...WILL PREVAIL MONDAY NIGHT.

&&

.FIRE WEATHER...

FIRE DANGER WILL BE RELATIVELY LOW TODAY THROUGH TONIGHT. A LARGE
UPPER LEVEL TROUGH CONTINUES TO EXPAND ACROSS THE COUNTRY TODAY WITH
ANOTHER EMBEDDED DISTURBANCE MOVING THROUGH THE TROUGH AND ACROSS
WYOMING TODAY...THEN INTO THE HIGH PLAINS BY TONIGHT. ANOTHER
DISTURBANCE WILL FOLLOW BETWEEN BETWEEN MIDNIGHT AND EARLY AFTERNOON
MONDAY...AFFECTING MAINLY THE NORTHERN FORECAST ZONES. A SURFACE
FRONT/BOUNDARY LAYS ACROSS NATRONA COUNTY AND WEST INTO SOUTHERN
FREMONT COUNTY THEN NORTHERN SWEETWATER COUNTY. ISOLATED TO
SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS WILL CONTINUE ACROSS
CENTRAL...EASTERN AND NORTHERN WYOMING THROUGH THE AFTERNOON BEFORE
BECOMING MORE ISOLATED IN NATURE FOR MOST LOCATIONS EXCEPT FOR THE
NORTHWEST WHICH WILL CONTINUE MORE SCATTERED. SNOW LEVELS WILL HOVER
BETWEEN 9-10KFT ACROSS THE NORTH. SOUTH OF THE FRONT/BOUNDARY
MENTIONED ABOVE...WEST TO WEST SOUTHWEST WINDS CONTINUE TODAY AT
15-25 MPH WITH GUSTS 35 TO 40 MPH POSSIBLE ALONG WITH MINIMUM RH
VALUES ONLY DROPPING TO 35 PERCENT AT THE LOW END. ISOLATED ERRATIC
OUTFLOW WIND GUSTS NEAR 45KTS WILL BE POSSIBLE WITH A FEW STORMS
THIS AFTERNOON.

&&

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

$$

SHORT TERM...BRAUN
LONG TERM...C.BAKER
AVIATION...BRAUN
FIRE WEATHER...BRAUN








000
FXUS65 KRIW 010556
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
1152 PM MDT SUN AUG 31 2014

.SHORT TERM...TONIGHT THROUGH MONDAY (ISSUED AT 300 PM MDT)

EXPANDING UPR LVL TROF ACROSS THE CONUS W OF THE MISSISSIPPI...W/
BASE OF TROF SWINGING EWD ACROSS WY TODAY. ANOTHER EMBEDDED SW TROF
MOVING THRU THE CNTRL FA INTO THE ERN PORTIONS OF THE STATE THIS
AFTERNOON. ANOTHER EMBEDDED SW LIES IN WAIT UPSTREAM JUST OFF THE
COAST OF OR/WA...AND WILL RACE INTO WRN/NWRN WY BY MONDAY MORNING.
AT THE SFC...GENERAL HIGH P TO THE W OF THE STATE...LOW P E WITH
FRONT/BOUNDARY BISECTING THE STATE FROM E TO SW CUTTING FROM NRN
NATRONA COUNTY...TO NRN SWEETWATER COUNTY AND W INTO SRN LINCOLN
COUNTY.

TODAY... OVERALL...MUCH COOLER CONDITIONS FROM FRONTAL
PASSAGE AND/OR SIGNIFICANT UPR LVL TEMP DROP AND CLOUD COVER.
CONTINUED  RELATIVELY STRONG GUSTY W TO WSW WINDS ACROSS THE SRN FA
SOUTH OF THE FRONT/BOUNDARY MENTIONED ABOVE...WITH GUSTY N TO NW
WINDS BEHIND THE FRONT. ANOTHER WEAKER FRONT LOOK TO BE LAYING
ACROSS MT AND WILL ENTER THE NRN AND ERN PORTION OF THE FA ON
MONDAY. ISOLATED TO SCATTERED SHOWERS AND ISOLATED THUNDER  ARE
MAKING THEIR WAY ACROSS PORTIONS OF CENTRAL AND EASTERN WY THIS
AFTERNOON...AND WILL CONTINUE AN EWD TRACK...DECREASING FROM W TO E
INTO THE EVENING. STRONGER STORMS WITH SMALL HAIL AND GUSTY WINDS
WILL BE MOST PROBABLE ERN FREMONT AND ACROSS NATRONA COUNTIES
NEAR/ALONG FRONT/BOUNDARY. CAPE AND SHEAR IN THIS AREA ARE 500-700
J/KG AND 25-30 KTS RESPECTIVELY...JUST ENOUGH TO WEAKLY ORGANIZE A
STORM OR TWO.

TONIGHT AND MONDAY...MAIN TROF PASSES E AND INTO THE GREAT PLAINS...UPR
LVL NW FLOW CONTINUES...AND THE OR/WA DISTURBANCE CONTINUES TO HEAD
THIS WAY THRU THE BACKSIDE OF THE LW TROF...ARRIVING NEAR THE WRN
BORDER BETWEEN 06 AND 09Z...THEN TRANSLATING ACROSS THE FA QUICKLY
BY EARLY AFTERNOON.  THIS WILL KEEP A NEARLY CONTINUAL CHC FOR SHRA
GOING ACROSS THE NW FA THROUGH AT LEAST MID TO LATE MORNING
MONDAY...AND ACROSS THE NRN/NERN FA INTO THE AFTERNOON. WHILE THIS
UPR LVL ENERGY WILL EXTEND WELL SOUTH AND OVR MOST OF THE
CWA...RAPID DRYING OF THE ATMOSPHERE WILL OCCUR BEHIND THE PASSAGE
OF THE MAIN TROF AXIS TONIGHT AND THROUGH MONDAY MORNING FROM W TO
E...AND THERE WILL NOT BE MUCH IN THE WAY OF MOISTURE TO ACT ON. A
FEW STRONGER STORMS MAY OCCUR OVR JOHNSON COUNTY BY EARLY AFTERNOON
WHERE SOME USEFUL MOISTURE WILL STILL BE LEFTOVER...CAPE WILL BE
MARGINAL AND SHEAR WILL BE MAXIMIZED ALONG AND NORTH OF A
CLIPPER-LIKE BOUNDARY/FRONT. SNOWFALL WILL BE POSSIBLE AGAIN ACROSS
THE NORTHERN MOUNTAINS...WITH GENERAL 1 INCH ACCUMULATIONS ABOVE
9500 FEET...AND PERHAPS A FEW AREAS ABOVE 10500 FEET RECEIVING UP TO
3 INCHES. NOT EXPECTING MUCH TO STICK TO ANY ASPHALT ROADWAYS
HOWEVER.

.LONG TERM...MONDAY NIGHT THROUGH SUNDAY

MONDAY NIGHT AS THE TROUGH CONTINUE TO MOVE EAST...HIGH PRESSURE
RIDGING WILL OCCUR OVER THE PACIFIC NORTHWEST.  THE MAIN TREND WILL
BE FOR DRYING WITH BREEZY TO WINDY CONDITIONS ACROSS THE SOUTH INTO
CENTRAL AREAS.

TUESDAY AND TUESDAY NIGHT DRY HIGH PRESSURE IS EXPECTED TO DOMINATE
THE WEATHER ACROSS THE AREA WITH INCREASING WEST TO SOUTHWEST WINDS
CENTRAL AND SOUTH WITH GENERAL WARMING. TEMPERATURES SHOULD WARM.

WEDNESDAY AND WEDNESDAY NIGHT  SOME MID LEVEL CLOUDS ARE EXPECTED TO
MOVE UP FROM THE GREAT BASIN IN THE AFTERNOON...OTHERWISE THE DRY
HIGH PRESSURE IS EXPECTED TO CONTINUE TO DOMINATE THE WEATHER WITH
CONTINUED SOUTHWEST WINDS ACROSS THE CENTRAL AND SOUTH WITH THE
WARMING TREND CONTINUING.

THURSDAY AND THURSDAY NIGHT  HIGH PRESSURE WILL SHIFT EAST WITH
INCREASING SOUTHWEST FLOW ALOFT BRINGING SOME PACIFIC MOISTURE ALOFT
OVER THE AREA.  SHOWERS ARE EXPECTED TO DEVELOP WITH ISOLATED
THUNDERSTORMS IN THE AFTERNOON...MOST NUMEROUS OVER THE WESTERN AND
CENTRAL MOUNTAINS.  INCREASED CLOUD COVER  AND A COLD FRONT MOVING
SOUTH FROM MONTANA WILL BRING COOLING.  MODELS STRONGER WITH COLD
FRONT THAN YESTERDAY WITH MORE SIGNIFICANT COOLING.

FRIDAY AND FRIDAY NIGHT  SHOWERS AND ISOLATED THUNDERSTORMS ARE
EXPECTED TO INCREASE OVER THE AREA AS PACIFIC MOISTURE INCREASES IN
SOUTHWEST FLOW ALOFT.  A COLD FRONT WILL CONTINUE TO MOVE SOUTH
INTO SOUTHERN WYOMING.  AGAIN MODELS CONTINUE TO BE STRONGER WITH
THIS COLD FRONT AND ASSOCIATED COOLING BRINGING THE COLD AIR THROUGH
THE SOUTHWEST WHILE YESTERDAY THE FRONT DID NOT MIKE IT THROUGH
CENTRAL WYOMING.

SATURDAY AND SATURDAY NIGHT SOUTHWEST FLOW ALOFT WILL REMAIN IN
PLACE OVER THE AREA WITH A STREAM OF PACIFIC MOISTURE CONTINUING TO
ADVECT INTO THE AREA SUPPORTING SCATTERED SHOWERS AND SOME ISOLATED
AFTERNOON THUNDERSTORMS.  A FRONT IS EXPECTED TO REMAIN THROUGH
SOUTHERN WYOMING WITH CONTINUED COOLING.

SUNDAY SOME DRYING IS EXPECTED IN THE WEST WITH POSSIBLE WARMING.
OVERALL LOW CONFIDENCE IN FORECAST FOR SUNDAY AS THE SPREAD IN
SOLUTIONS WITH THE EXTENDED MODELS BECOMES MORE SIGNIFICANT.

&&

.AVIATION.../06Z ISSUANCE/

A LAST IN A SERIES OF UPPER LEVEL DISTURBANCES IN NW FLOW WILL RACE
SE INTO NW WYOMING THIS MORNING AND INTO THE HIGH PLAINS LATE THIS
AFTERNOON.   AREAS OF MVFR/IFR CIGS WITH SCT -SHRA...SNOW LEVELS
NEAR 9.5KFT WITH FRQT MTN OBSCURATIONS ...WILL SPREAD ACROSS
NORTHERN WYOMING FROM YELLOWSTONE NATIONAL PARK TO A VCNTY AND NORTH
OF KCOD-KBYG LINE 09Z-15Z.  MOST OF THIS ACTIVITY WILL PUSH FROM
VCNTY OF THE BIGHORN RANGE AND EASTWARD BY EARLY AFTERNOON.  SOME OF
THIS SHOWER ACTIVITY MAY REACH AS FAR AS KCPR IN THE LATE MORNING
AND AFTERNOON.  W-NW WIND AT 15-25KT AND MAINLY SKC CONDITIONS WILL
PREVAIL ACROSS THE SOUTHERN THIRD OF THE AREA IN THE AFTERNOON.

SKC CONDITIONS WITH DIMINISHING WIND...PATCHY FOG IN THE WESTERN
VALLEYS...WILL PREVAIL MONDAY NIGHT.

&&

.FIRE WEATHER...

FIRE DANGER WILL BE RELATIVELY LOW TODAY THROUGH TONIGHT. A LARGE
UPPER LEVEL TROUGH CONTINUES TO EXPAND ACROSS THE COUNTRY TODAY WITH
ANOTHER EMBEDDED DISTURBANCE MOVING THROUGH THE TROUGH AND ACROSS
WYOMING TODAY...THEN INTO THE HIGH PLAINS BY TONIGHT. ANOTHER
DISTURBANCE WILL FOLLOW BETWEEN BETWEEN MIDNIGHT AND EARLY AFTERNOON
MONDAY...AFFECTING MAINLY THE NORTHERN FORECAST ZONES. A SURFACE
FRONT/BOUNDARY LAYS ACROSS NATRONA COUNTY AND WEST INTO SOUTHERN
FREMONT COUNTY THEN NORTHERN SWEETWATER COUNTY. ISOLATED TO
SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS WILL CONTINUE ACROSS
CENTRAL...EASTERN AND NORTHERN WYOMING THROUGH THE AFTERNOON BEFORE
BECOMING MORE ISOLATED IN NATURE FOR MOST LOCATIONS EXCEPT FOR THE
NORTHWEST WHICH WILL CONTINUE MORE SCATTERED. SNOW LEVELS WILL HOVER
BETWEEN 9-10KFT ACROSS THE NORTH. SOUTH OF THE FRONT/BOUNDARY
MENTIONED ABOVE...WEST TO WEST SOUTHWEST WINDS CONTINUE TODAY AT
15-25 MPH WITH GUSTS 35 TO 40 MPH POSSIBLE ALONG WITH MINIMUM RH
VALUES ONLY DROPPING TO 35 PERCENT AT THE LOW END. ISOLATED ERRATIC
OUTFLOW WIND GUSTS NEAR 45KTS WILL BE POSSIBLE WITH A FEW STORMS
THIS AFTERNOON.

&&

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

$$

SHORT TERM...BRAUN
LONG TERM...C.BAKER
AVIATION...BRAUN
FIRE WEATHER...BRAUN








000
FXUS63 KUNR 010459
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
1059 PM MDT SUN AUG 31 2014

.SHORT TERM...THIS EVENING THROUGH MONDAY NIGHT
ISSUED AT 300 PM MDT SUN AUG 31 2014

CURRENT SURFACE ANALYSIS SHOWS LOW PRESSURE OVER NORTHWEST
MN...WITH COLD FRONT WELL EAST OF OUR FORECAST AREA. UPPER LEVEL
ANALYSIS SHOWS BROAD TROF OVER THE WESTERN CONUS...WITH A SERIES
OF SHORTWAVES WITHIN THE TROF MOVING EAST THROUGH THE ROCKIES AND
PLAINS. LAST NIGHTS WAVE HAS MOVED WELL EAST OF THE AREA...WHILE
THE NEXT ONE IS MOVING QUICKLY ACROSS EASTERN WY INTO WESTERN SD
AND WESTERN NEB. KUDX RADAR SHOWS NUMEROUS SHOWERS AND
THUNDERSTORMS OVER MUCH OF NORTHEAST WY AND WESTERN SD...WITH THE
HEAVIEST ACTIVITY GENERALLY OVER AND AROUND THE BLACK HILLS. TEMPS
ARE IN THE 60S TO MID 70S WITH NORTHERLY WINDS IN MOST AREAS.

THE UNSETTLED WEATHER PATTERN WILL CONTINUE THROUGH LABOR DAY AS
THIS LATEST DISTURBANCE EXITS THIS EVENING AND THE NEXT ONE PUSHES
THROUGH ON MONDAY. A BREAK IN THE PATTERN CAN BE EXPECTED FOR
TUESDAY AND WEDNESDAY.

FOR LATE TODAY AND TONIGHT...SHOWERS AND THUNDERSTORMS WILL CONTINUE
TO TRACK EAST ACROSS THE AREA...ENDING ACROSS NORTHEAST WY BY EARLY
EVENING AND FROM WEST TO EAST ACROSS WESTERN SD DURING THE EVENING.
THE BEST CHANCES FOR PCPN WILL BE EAST OF THE BLACK HILLS DURING THE
EVENING. SKIES WILL CLEAR OUT BEHIND THE WAVE FOR A WHILE...BUT
CLOUDS WILL INCREASE AGAIN FROM THE WEST LATE TONIGHT INTO MONDAY
MORNING AS THE NEXT DISTURBANCE APPROACHES. WILL KEEP A SLIGHT
CHANCE FOR SHOWERS LATE TONIGHT OVER NORTHEAST WY AND FAR NORTHWEST
SD. A COOL NIGHT IS ON TAP WITH LOWS IN THE MID 40S TO MID
50S...COOLEST OVER THE BLACK HILLS AND USUAL VALLEY LOCATIONS.

ANOTHER COOL DAY CAN BE EXPECTED MONDAY...WITH CHANCES FOR SHOWERS
AND STORMS INCREASING THROUGH THE MORNING AND INTO THE AFTERNOON
FROM WEST TO EAST. SHOWERS WILL LIKELY NOT BE AS NUMEROUS AS
TODAY...BUT SHOULD BE AT LEAST SCATTERED IN COVERAGE ACROSS MOST
AREAS. HIGHS WILL BE IN THE 70S ACROSS MOST OF THE PLAINS...WITH 60S
OVER THE BLACK HILLS. THREAT FOR SEVERE WEATHER WILL AGAIN BE
MINIMAL AT BEST WITH RELATIVELY WEAK INSTABILITY IN PLACE FOR STRONG
STORMS. SHOWERS WILL EXIT THE AREA FROM WEST TO EAST LATE MONDAY AND
MONDAY EVENING.

&&

.LONG TERM...TUESDAY THROUGH SUNDAY
ISSUED AT 300 PM MDT SUN AUG 31 2014

AN UPPER TROUGH WILL DEEPEN OVER THE PACIFIC NORTHWEST
TUESDAY/WEDNESDAY BRINGING A FLAT UPPER RIDGE/THERMAL RIDGE OVER THE
AREA. RESULT WILL BE DRIER WEATHER AND WARMER TEMPERATURES. A
SPIRITED SHORTWAVE WILL PUSH THROUGH THE CWA WEDNESDAY
NIGHT/THURSDAY BRINGING A SHARP COLD FRONT AND LOWER TEMPERATURES
FOR THURSDAY/FRIDAY. SMALL POPS LOOK REASONABLE BEHIND FRONT THROUGH
NEXT WEEKEND GIVEN WEST/NORTHWEST FLOW ALOFT.

&&

.AVIATION...FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT
ISSUED AT 1057 PM MDT SUN AUG 31 2014

ISOLATED SHOWERS AND POSSIBLY A THUNDERSTORM WILL BE POSSIBLE OVER
NORTHEASTERN WYOMING AND PARTS OF FAR WESTERN SOUTH DAKOTA DURING
THE REST OF THE NIGHT AND INTO MONDAY MORNING. SHOWERS AND A FEW
THUNDERSTORMS WILL REDEVELOP OVER NORTHEASTERN WYOMING AND FAR
SOUTHWESTERN SOUTH DAKOTA LATE MONDAY MORNING AND THEN WILL SPREAD
ACROSS MUCH OF THE REST OF WESTERN SOUTH DAKOTA DURING THE
AFTERNOON. LOCAL MVFR CIGS/IFR VSBYS ARE POSSIBLE WITH THE STRONGER
SHOWERS/STORMS.

&&

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

$$

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







000
FXUS63 KUNR 010459
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
1059 PM MDT SUN AUG 31 2014

.SHORT TERM...THIS EVENING THROUGH MONDAY NIGHT
ISSUED AT 300 PM MDT SUN AUG 31 2014

CURRENT SURFACE ANALYSIS SHOWS LOW PRESSURE OVER NORTHWEST
MN...WITH COLD FRONT WELL EAST OF OUR FORECAST AREA. UPPER LEVEL
ANALYSIS SHOWS BROAD TROF OVER THE WESTERN CONUS...WITH A SERIES
OF SHORTWAVES WITHIN THE TROF MOVING EAST THROUGH THE ROCKIES AND
PLAINS. LAST NIGHTS WAVE HAS MOVED WELL EAST OF THE AREA...WHILE
THE NEXT ONE IS MOVING QUICKLY ACROSS EASTERN WY INTO WESTERN SD
AND WESTERN NEB. KUDX RADAR SHOWS NUMEROUS SHOWERS AND
THUNDERSTORMS OVER MUCH OF NORTHEAST WY AND WESTERN SD...WITH THE
HEAVIEST ACTIVITY GENERALLY OVER AND AROUND THE BLACK HILLS. TEMPS
ARE IN THE 60S TO MID 70S WITH NORTHERLY WINDS IN MOST AREAS.

THE UNSETTLED WEATHER PATTERN WILL CONTINUE THROUGH LABOR DAY AS
THIS LATEST DISTURBANCE EXITS THIS EVENING AND THE NEXT ONE PUSHES
THROUGH ON MONDAY. A BREAK IN THE PATTERN CAN BE EXPECTED FOR
TUESDAY AND WEDNESDAY.

FOR LATE TODAY AND TONIGHT...SHOWERS AND THUNDERSTORMS WILL CONTINUE
TO TRACK EAST ACROSS THE AREA...ENDING ACROSS NORTHEAST WY BY EARLY
EVENING AND FROM WEST TO EAST ACROSS WESTERN SD DURING THE EVENING.
THE BEST CHANCES FOR PCPN WILL BE EAST OF THE BLACK HILLS DURING THE
EVENING. SKIES WILL CLEAR OUT BEHIND THE WAVE FOR A WHILE...BUT
CLOUDS WILL INCREASE AGAIN FROM THE WEST LATE TONIGHT INTO MONDAY
MORNING AS THE NEXT DISTURBANCE APPROACHES. WILL KEEP A SLIGHT
CHANCE FOR SHOWERS LATE TONIGHT OVER NORTHEAST WY AND FAR NORTHWEST
SD. A COOL NIGHT IS ON TAP WITH LOWS IN THE MID 40S TO MID
50S...COOLEST OVER THE BLACK HILLS AND USUAL VALLEY LOCATIONS.

ANOTHER COOL DAY CAN BE EXPECTED MONDAY...WITH CHANCES FOR SHOWERS
AND STORMS INCREASING THROUGH THE MORNING AND INTO THE AFTERNOON
FROM WEST TO EAST. SHOWERS WILL LIKELY NOT BE AS NUMEROUS AS
TODAY...BUT SHOULD BE AT LEAST SCATTERED IN COVERAGE ACROSS MOST
AREAS. HIGHS WILL BE IN THE 70S ACROSS MOST OF THE PLAINS...WITH 60S
OVER THE BLACK HILLS. THREAT FOR SEVERE WEATHER WILL AGAIN BE
MINIMAL AT BEST WITH RELATIVELY WEAK INSTABILITY IN PLACE FOR STRONG
STORMS. SHOWERS WILL EXIT THE AREA FROM WEST TO EAST LATE MONDAY AND
MONDAY EVENING.

&&

.LONG TERM...TUESDAY THROUGH SUNDAY
ISSUED AT 300 PM MDT SUN AUG 31 2014

AN UPPER TROUGH WILL DEEPEN OVER THE PACIFIC NORTHWEST
TUESDAY/WEDNESDAY BRINGING A FLAT UPPER RIDGE/THERMAL RIDGE OVER THE
AREA. RESULT WILL BE DRIER WEATHER AND WARMER TEMPERATURES. A
SPIRITED SHORTWAVE WILL PUSH THROUGH THE CWA WEDNESDAY
NIGHT/THURSDAY BRINGING A SHARP COLD FRONT AND LOWER TEMPERATURES
FOR THURSDAY/FRIDAY. SMALL POPS LOOK REASONABLE BEHIND FRONT THROUGH
NEXT WEEKEND GIVEN WEST/NORTHWEST FLOW ALOFT.

&&

.AVIATION...FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT
ISSUED AT 1057 PM MDT SUN AUG 31 2014

ISOLATED SHOWERS AND POSSIBLY A THUNDERSTORM WILL BE POSSIBLE OVER
NORTHEASTERN WYOMING AND PARTS OF FAR WESTERN SOUTH DAKOTA DURING
THE REST OF THE NIGHT AND INTO MONDAY MORNING. SHOWERS AND A FEW
THUNDERSTORMS WILL REDEVELOP OVER NORTHEASTERN WYOMING AND FAR
SOUTHWESTERN SOUTH DAKOTA LATE MONDAY MORNING AND THEN WILL SPREAD
ACROSS MUCH OF THE REST OF WESTERN SOUTH DAKOTA DURING THE
AFTERNOON. LOCAL MVFR CIGS/IFR VSBYS ARE POSSIBLE WITH THE STRONGER
SHOWERS/STORMS.

&&

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

$$

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






000
FXUS65 KCYS 010444
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
1044 PM MDT SUN AUG 31 2014

.UPDATE...
ISSUED AT 816 PM MDT SUN AUG 31 2014

SHOWER AND TSTM ACTIVITY HAS GREATLY DIMINISHED ACROSS THE AREA
THIS EVE. SFC OBSERVATIONS INDICATE THE COLD FRONT HAS MOVED TO
THE SOUTHEAST OF THE CWA WITH DRYING/SUBSIDENCE OCCURRING IN ITS
WAKE. RADAR IS CLEAR OVER OUR ZONES AS OF 02Z AND WOULD EXPECT
LITTLE ADDITIONAL DEVELOPMENT TONIGHT AS WATER VAPOR SATELLITE
SHOWS THE MAIN SHORT WAVE AXIS MOVING EASTWARD INTO CENTRAL NE.
KEPT ISOLATED POPS IN THE PANHANDLE THROUGH 03Z AS SOME MID AND
HIGH LEVEL MOISTURE LINGERS. DRY OVERNIGHT WITH SUBSIDING MOTION
ALOFT. ADJUSTED CLOUD TRENDS TO SHOW MORE CLEARING OVERNIGHT AND
THEN INCREASING AGAIN AROUND SUNRISE MON WITH THE NEXT PIECE OF
SHORTWAVE ENERGY CURRENTLY OVER THE INTERMOUNTAIN WEST.

SHORT TERM...(THIS EVENING THROUGH TUESDAY NIGHT)
ISSUED AT 345 PM MDT SUN AUG 31 2014

WATER VAPOR IMAGERY THIS AFTERNOON SHOWS THE UPPER LEVEL SHORTWAVE
MOVING OVER THE FORECAST AREA WITHIN THE LEFT EXIT REGION OF A 100
KT JET. AS OF 3 PM...THE SFC COLD FRONT LOOKS TO EXTEND ROUGHLY
FROM SOUTHEAST NIOBRARA COUNTY...THROUGH CONVERSE COUNTY...AND
WESTWARD THROUGH NATRONA COUNTY AND IS STEADILY MOVING SOUTH.
SCATTERED TO NUMEROUS SHOWERS AND T-STORMS HAVE DEVELOPED ACROSS
NORTHERN PORTIONS OF THE FORECAST AREA THIS AFTERNOON WITHIN THE
STRONGEST UPPER LEVEL AND SFC FORCING...WITH A FEW UPDRAFTS
SPIKING ABOVE 20KFT WITH THE HELP OF 500 TO 1000 J/KG OF MLCAPE.
MAINTAINED MENTION IN THE FORECAST FOR GUSTY WINDS AND SMALL HAIL
WITH THIS ACTIVITY THROUGH THE LATE AFTERNOON. 30 TO 40 KTS OF
BULK SHEAR IS ANALYZED OVER THE NEB PANHANDLE COINCIDENT WITH THE
HIGHER VALUES OF INSTABILITY...SO THE POSSIBILITY DOES EXIST FOR A
FEW STORMS TO BECOME STRONGER AS THEY TREK EAST TOWARD THE
SANDHILLS. WEAKER CONVECTION ALSO DEVELOPED OVER THE MOUNTAINS OF
SOUTHEAST WYOMING AND COLORADO EARLIER...WITH SOME OF THIS ACTIVITY
MOVING OFF THE HIGH TERRAIN AND ALONG THE CHEYENNE RIDGE AS WELL.
WATER VAPOR IMAGERY AND SPC MESOANALYSIS DATA INDICATE A BROADER
AREA OF SUBSIDENCE WAS OVER THIS AREA DURING THIS TIME...AND
LIKELY STUNTED THE GROWTH OF THE CONVECTION WHILE FORCING SOME
STRONGER WIND GUSTS AROUND 50 MPH TO THE SFC. A FEW SHOWERS
CONTINUE TO DEVELOP OVER MOUNTAINS AT THIS HOUR...BUT EXPECT A
SIMILAR TREND FOR WEAK BUT GUSTY SHOWERS AS DRIER AIR AND SOME
UPPER LEVEL SUBSIDENCE REMAIN IN PLACE HERE.

THE FRONT WILL CONTINUE TO MOVE SOUTH ACROSS EASTERN COUNTIES
THROUGH THIS EVENING WHILE DRIER AIR MOVES OVERHEAD AND SUBSIDENCE
BECOMES MORE WIDESPREAD. THUS EXPECT ACTIVITY TO COME TO AN END
QUICKLY AROUND SUNSET. ANOTHER SHORTWAVE WILL MOVE OVERHEAD TOMORROW
AFTERNOON...ALTHOUGH A MUCH DRIER AIRMASS WILL BE IN PLACE WHICH
WILL MINIMIZE COVERAGE OF SHOWERS AND STORMS. THE FOCUS FOR ACTIVITY
WILL BE ACROSS THE NORTHERN ZONES ONCE AGAIN ON THE LEADING EDGE OF
ANOTHER BACKDOOR COLD FRONT MOVING WITH THE UPPER WAVE. A FEW STORMS
COULD BECOME STRONG IN THIS AREA AS 30 KTS OF SHEAR IS PROGGED BY
THE NAM HERE. THE ONE LIMITING FACTOR WILL BE AVAILABLE INSTABILITY AS
MODELS DEVELOP ONLY ABOUT 500 J/KG OF CAPE BY THE AFTERNOON.
CANNOT RULE OUT A FEW WEAKER SHOWERS/STORMS DEVELOPING AND MOVING
OFF THE LARAMIE RANGE AS WELL IN THE LATE AFTERNOON BUT THESE WILL
BE WEAK AND VERY ISOLATED.

DRY ZONAL FLOW WILL THEN TAKE AHOLD OF THE FORECAST AREA FOR
TUESDAY...WITH TEMPS WARMING BACK TO MORE NORMAL VALUES FOR THIS
TIME OF YEAR. HUMIDITIES LOOK TO DROP INTO THE TEENS AND 20S FOR
MUCH OF THE AREA...WHILE  WINDS WILL CONTINUE TO BE GUSTY ALONG AND
WEST OF THE LARAMIE RANGE. WILL CONTINUE TO MONITOR TUESDAY FOR
ELEVATED FIRE WEATHER CONCERNS.

.LONG TERM...(WEDNESDAY THROUGH SATURDAY)
ISSUED AT 345 PM MDT SUN AUG 31 2014

WEDNESDAY WILL BE THE WARMEST DAY OF THE EXTENDED PERIOD WITH
SOUTHWESTERLY FLOW ALOFT AND A LEE TROUGH AT THE SFC.  700MB TEMPS
WILL RISE TO 16C WITH AROUND 30C AT 850MB.  HIGHS OVER THE PLAINS
WILL BE IN THE UPPER 80S TO LOW 90S...WHICH IS 5-10 DEGREES ABOVE
NORMAL FOR EARLY SEPTEMBER.  MAY HAVE TO DEAL WITH SOME FIRE WEATHER
CONCERNS OVER SOUTHEAST WY AS MIN RH VALUES DROP TO AROUND 15
PERCENT AND WINDS WILL BE BREEZY...ESPECIALLY TO THE WEST OF THE
LARAMIE RANGE.  UPPER LEVEL WAVE PUSHES FROM THE NORTHERN ROCKIES ON
WED TOWARD NORTH DAKOTA ON THURS.  THIS WILL PUSH A COLD FRONT
THROUGH THE CWA ON THURS MORNING WITH 10-15 DEGREES OF COOLING.  IT
IS GENERALLY A DRY FRONTAL PASSAGE...AT LEAST INITIALLY.  BY THURS
NIGHT INTO FRI THIS COULD CHANGE AS ISENTROPIC LIFT COMBINES WITH
IMPROVING JET DYNAMICS SUCH THAT SCATTERED SHOWERS DEVELOP OVER
PORTIONS OF THE CWA.  THE ECMWF HAS WIDESPREAD SHOWERS ON THURS
NIGHT WHEREAS THE GFS HAS THIS AREA FURTHER SOUTH OVER NORTHERN
COLORADO.  LLVL SOUTHEASTERLY UPSLOPE WILL CONTINUE THROUGH SATURDAY
WITH WEAK SHORTWAVES MOVING ACROSS THE REGION FROM THE SOUTHWEST.
SEEMS LIKE A FAVORABLE PATTERN FOR AT LEAST ISOLATED TO SCATTERED
SHOWERS AT TIMES ALONG WITH INCREASED CLOUD COVER AND GENERALLY HAVE
SLIGHT CHANCE POPS ON FRI AND SAT.  INSTABILITY IS QUITE LIMITED
THROUGH FRI...THEN IMPROVES SOME BY SAT (CAPE VALUES INCREASE TO
500-750 J/KG).

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY EVENING)
ISSUED AT 1041 PM MDT SUN AUG 31 2014

VFR CONDITIONS EXPECTED OVERNIGHT INTO MONDAY. WINDS WILL BEGIN TO
PICK UP AFTER 16Z FOR OUR SOUTHEAST WYOMING AIRPORTS.
OTHERWISE...NO WEATHER IMAPCTS TO AVIATION INTERESTS.

&&

.FIRE WEATHER...
ISSUED AT 345 PM MDT SUN AUG 31 2014

SCATTERED SHOWERS AND T-STORMS WILL CONTINUE OVER THE DISTRICT
THROUGH EARLY THIS EVENING BEFORE COMING TO AN END TONIGHT. LIGHT
TO MODERATE RAIN...GUSTY DOWNDRAFT WINDS...AND OCCASIONAL
LIGHTNING WILL ACCOMPANY THE STORMS. A WEAK DISTURBANCE MOVING
OVERHEAD ON MONDAY WILL BRING A CHANCE FOR MORE ISOLATED SHOWERS
AND STORMS MAINLY OVER NORTHERN AND EASTERN PORTIONS OF THE
DISTRICT IN THE AFTERNOON. LIGHT RAINFALL AND GUSTY WINDS WILL
REMAIN A POSSIBILITY WITH THIS ACTIVITY. A MUCH DRIER AIRMASS WILL
MOVE OVERHEAD TUESDAY AND WILL REMAIN IN PLACE THROUGH WEDNESDAY.
TEMPERATURES WILL WARM BACK TO ABOVE NORMAL READINGS BY
WEDNESDAY AS WELL...WHILE WEST TO SOUTHWEST WINDS WILL REMAIN
GUSTY IN AREAS ALONG AND WEST OF THE LARAMIE RANGE.

&&

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

$$

UPDATE...HAMMER
SHORT TERM...RJM
LONG TERM...FINCH
AVIATION...CLAYCOMB
FIRE WEATHER...RJM








000
FXUS65 KCYS 010444
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
1044 PM MDT SUN AUG 31 2014

.UPDATE...
ISSUED AT 816 PM MDT SUN AUG 31 2014

SHOWER AND TSTM ACTIVITY HAS GREATLY DIMINISHED ACROSS THE AREA
THIS EVE. SFC OBSERVATIONS INDICATE THE COLD FRONT HAS MOVED TO
THE SOUTHEAST OF THE CWA WITH DRYING/SUBSIDENCE OCCURRING IN ITS
WAKE. RADAR IS CLEAR OVER OUR ZONES AS OF 02Z AND WOULD EXPECT
LITTLE ADDITIONAL DEVELOPMENT TONIGHT AS WATER VAPOR SATELLITE
SHOWS THE MAIN SHORT WAVE AXIS MOVING EASTWARD INTO CENTRAL NE.
KEPT ISOLATED POPS IN THE PANHANDLE THROUGH 03Z AS SOME MID AND
HIGH LEVEL MOISTURE LINGERS. DRY OVERNIGHT WITH SUBSIDING MOTION
ALOFT. ADJUSTED CLOUD TRENDS TO SHOW MORE CLEARING OVERNIGHT AND
THEN INCREASING AGAIN AROUND SUNRISE MON WITH THE NEXT PIECE OF
SHORTWAVE ENERGY CURRENTLY OVER THE INTERMOUNTAIN WEST.

SHORT TERM...(THIS EVENING THROUGH TUESDAY NIGHT)
ISSUED AT 345 PM MDT SUN AUG 31 2014

WATER VAPOR IMAGERY THIS AFTERNOON SHOWS THE UPPER LEVEL SHORTWAVE
MOVING OVER THE FORECAST AREA WITHIN THE LEFT EXIT REGION OF A 100
KT JET. AS OF 3 PM...THE SFC COLD FRONT LOOKS TO EXTEND ROUGHLY
FROM SOUTHEAST NIOBRARA COUNTY...THROUGH CONVERSE COUNTY...AND
WESTWARD THROUGH NATRONA COUNTY AND IS STEADILY MOVING SOUTH.
SCATTERED TO NUMEROUS SHOWERS AND T-STORMS HAVE DEVELOPED ACROSS
NORTHERN PORTIONS OF THE FORECAST AREA THIS AFTERNOON WITHIN THE
STRONGEST UPPER LEVEL AND SFC FORCING...WITH A FEW UPDRAFTS
SPIKING ABOVE 20KFT WITH THE HELP OF 500 TO 1000 J/KG OF MLCAPE.
MAINTAINED MENTION IN THE FORECAST FOR GUSTY WINDS AND SMALL HAIL
WITH THIS ACTIVITY THROUGH THE LATE AFTERNOON. 30 TO 40 KTS OF
BULK SHEAR IS ANALYZED OVER THE NEB PANHANDLE COINCIDENT WITH THE
HIGHER VALUES OF INSTABILITY...SO THE POSSIBILITY DOES EXIST FOR A
FEW STORMS TO BECOME STRONGER AS THEY TREK EAST TOWARD THE
SANDHILLS. WEAKER CONVECTION ALSO DEVELOPED OVER THE MOUNTAINS OF
SOUTHEAST WYOMING AND COLORADO EARLIER...WITH SOME OF THIS ACTIVITY
MOVING OFF THE HIGH TERRAIN AND ALONG THE CHEYENNE RIDGE AS WELL.
WATER VAPOR IMAGERY AND SPC MESOANALYSIS DATA INDICATE A BROADER
AREA OF SUBSIDENCE WAS OVER THIS AREA DURING THIS TIME...AND
LIKELY STUNTED THE GROWTH OF THE CONVECTION WHILE FORCING SOME
STRONGER WIND GUSTS AROUND 50 MPH TO THE SFC. A FEW SHOWERS
CONTINUE TO DEVELOP OVER MOUNTAINS AT THIS HOUR...BUT EXPECT A
SIMILAR TREND FOR WEAK BUT GUSTY SHOWERS AS DRIER AIR AND SOME
UPPER LEVEL SUBSIDENCE REMAIN IN PLACE HERE.

THE FRONT WILL CONTINUE TO MOVE SOUTH ACROSS EASTERN COUNTIES
THROUGH THIS EVENING WHILE DRIER AIR MOVES OVERHEAD AND SUBSIDENCE
BECOMES MORE WIDESPREAD. THUS EXPECT ACTIVITY TO COME TO AN END
QUICKLY AROUND SUNSET. ANOTHER SHORTWAVE WILL MOVE OVERHEAD TOMORROW
AFTERNOON...ALTHOUGH A MUCH DRIER AIRMASS WILL BE IN PLACE WHICH
WILL MINIMIZE COVERAGE OF SHOWERS AND STORMS. THE FOCUS FOR ACTIVITY
WILL BE ACROSS THE NORTHERN ZONES ONCE AGAIN ON THE LEADING EDGE OF
ANOTHER BACKDOOR COLD FRONT MOVING WITH THE UPPER WAVE. A FEW STORMS
COULD BECOME STRONG IN THIS AREA AS 30 KTS OF SHEAR IS PROGGED BY
THE NAM HERE. THE ONE LIMITING FACTOR WILL BE AVAILABLE INSTABILITY AS
MODELS DEVELOP ONLY ABOUT 500 J/KG OF CAPE BY THE AFTERNOON.
CANNOT RULE OUT A FEW WEAKER SHOWERS/STORMS DEVELOPING AND MOVING
OFF THE LARAMIE RANGE AS WELL IN THE LATE AFTERNOON BUT THESE WILL
BE WEAK AND VERY ISOLATED.

DRY ZONAL FLOW WILL THEN TAKE AHOLD OF THE FORECAST AREA FOR
TUESDAY...WITH TEMPS WARMING BACK TO MORE NORMAL VALUES FOR THIS
TIME OF YEAR. HUMIDITIES LOOK TO DROP INTO THE TEENS AND 20S FOR
MUCH OF THE AREA...WHILE  WINDS WILL CONTINUE TO BE GUSTY ALONG AND
WEST OF THE LARAMIE RANGE. WILL CONTINUE TO MONITOR TUESDAY FOR
ELEVATED FIRE WEATHER CONCERNS.

.LONG TERM...(WEDNESDAY THROUGH SATURDAY)
ISSUED AT 345 PM MDT SUN AUG 31 2014

WEDNESDAY WILL BE THE WARMEST DAY OF THE EXTENDED PERIOD WITH
SOUTHWESTERLY FLOW ALOFT AND A LEE TROUGH AT THE SFC.  700MB TEMPS
WILL RISE TO 16C WITH AROUND 30C AT 850MB.  HIGHS OVER THE PLAINS
WILL BE IN THE UPPER 80S TO LOW 90S...WHICH IS 5-10 DEGREES ABOVE
NORMAL FOR EARLY SEPTEMBER.  MAY HAVE TO DEAL WITH SOME FIRE WEATHER
CONCERNS OVER SOUTHEAST WY AS MIN RH VALUES DROP TO AROUND 15
PERCENT AND WINDS WILL BE BREEZY...ESPECIALLY TO THE WEST OF THE
LARAMIE RANGE.  UPPER LEVEL WAVE PUSHES FROM THE NORTHERN ROCKIES ON
WED TOWARD NORTH DAKOTA ON THURS.  THIS WILL PUSH A COLD FRONT
THROUGH THE CWA ON THURS MORNING WITH 10-15 DEGREES OF COOLING.  IT
IS GENERALLY A DRY FRONTAL PASSAGE...AT LEAST INITIALLY.  BY THURS
NIGHT INTO FRI THIS COULD CHANGE AS ISENTROPIC LIFT COMBINES WITH
IMPROVING JET DYNAMICS SUCH THAT SCATTERED SHOWERS DEVELOP OVER
PORTIONS OF THE CWA.  THE ECMWF HAS WIDESPREAD SHOWERS ON THURS
NIGHT WHEREAS THE GFS HAS THIS AREA FURTHER SOUTH OVER NORTHERN
COLORADO.  LLVL SOUTHEASTERLY UPSLOPE WILL CONTINUE THROUGH SATURDAY
WITH WEAK SHORTWAVES MOVING ACROSS THE REGION FROM THE SOUTHWEST.
SEEMS LIKE A FAVORABLE PATTERN FOR AT LEAST ISOLATED TO SCATTERED
SHOWERS AT TIMES ALONG WITH INCREASED CLOUD COVER AND GENERALLY HAVE
SLIGHT CHANCE POPS ON FRI AND SAT.  INSTABILITY IS QUITE LIMITED
THROUGH FRI...THEN IMPROVES SOME BY SAT (CAPE VALUES INCREASE TO
500-750 J/KG).

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY EVENING)
ISSUED AT 1041 PM MDT SUN AUG 31 2014

VFR CONDITIONS EXPECTED OVERNIGHT INTO MONDAY. WINDS WILL BEGIN TO
PICK UP AFTER 16Z FOR OUR SOUTHEAST WYOMING AIRPORTS.
OTHERWISE...NO WEATHER IMAPCTS TO AVIATION INTERESTS.

&&

.FIRE WEATHER...
ISSUED AT 345 PM MDT SUN AUG 31 2014

SCATTERED SHOWERS AND T-STORMS WILL CONTINUE OVER THE DISTRICT
THROUGH EARLY THIS EVENING BEFORE COMING TO AN END TONIGHT. LIGHT
TO MODERATE RAIN...GUSTY DOWNDRAFT WINDS...AND OCCASIONAL
LIGHTNING WILL ACCOMPANY THE STORMS. A WEAK DISTURBANCE MOVING
OVERHEAD ON MONDAY WILL BRING A CHANCE FOR MORE ISOLATED SHOWERS
AND STORMS MAINLY OVER NORTHERN AND EASTERN PORTIONS OF THE
DISTRICT IN THE AFTERNOON. LIGHT RAINFALL AND GUSTY WINDS WILL
REMAIN A POSSIBILITY WITH THIS ACTIVITY. A MUCH DRIER AIRMASS WILL
MOVE OVERHEAD TUESDAY AND WILL REMAIN IN PLACE THROUGH WEDNESDAY.
TEMPERATURES WILL WARM BACK TO ABOVE NORMAL READINGS BY
WEDNESDAY AS WELL...WHILE WEST TO SOUTHWEST WINDS WILL REMAIN
GUSTY IN AREAS ALONG AND WEST OF THE LARAMIE RANGE.

&&

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

$$

UPDATE...HAMMER
SHORT TERM...RJM
LONG TERM...FINCH
AVIATION...CLAYCOMB
FIRE WEATHER...RJM








000
FXUS65 KCYS 010444
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
1044 PM MDT SUN AUG 31 2014

.UPDATE...
ISSUED AT 816 PM MDT SUN AUG 31 2014

SHOWER AND TSTM ACTIVITY HAS GREATLY DIMINISHED ACROSS THE AREA
THIS EVE. SFC OBSERVATIONS INDICATE THE COLD FRONT HAS MOVED TO
THE SOUTHEAST OF THE CWA WITH DRYING/SUBSIDENCE OCCURRING IN ITS
WAKE. RADAR IS CLEAR OVER OUR ZONES AS OF 02Z AND WOULD EXPECT
LITTLE ADDITIONAL DEVELOPMENT TONIGHT AS WATER VAPOR SATELLITE
SHOWS THE MAIN SHORT WAVE AXIS MOVING EASTWARD INTO CENTRAL NE.
KEPT ISOLATED POPS IN THE PANHANDLE THROUGH 03Z AS SOME MID AND
HIGH LEVEL MOISTURE LINGERS. DRY OVERNIGHT WITH SUBSIDING MOTION
ALOFT. ADJUSTED CLOUD TRENDS TO SHOW MORE CLEARING OVERNIGHT AND
THEN INCREASING AGAIN AROUND SUNRISE MON WITH THE NEXT PIECE OF
SHORTWAVE ENERGY CURRENTLY OVER THE INTERMOUNTAIN WEST.

SHORT TERM...(THIS EVENING THROUGH TUESDAY NIGHT)
ISSUED AT 345 PM MDT SUN AUG 31 2014

WATER VAPOR IMAGERY THIS AFTERNOON SHOWS THE UPPER LEVEL SHORTWAVE
MOVING OVER THE FORECAST AREA WITHIN THE LEFT EXIT REGION OF A 100
KT JET. AS OF 3 PM...THE SFC COLD FRONT LOOKS TO EXTEND ROUGHLY
FROM SOUTHEAST NIOBRARA COUNTY...THROUGH CONVERSE COUNTY...AND
WESTWARD THROUGH NATRONA COUNTY AND IS STEADILY MOVING SOUTH.
SCATTERED TO NUMEROUS SHOWERS AND T-STORMS HAVE DEVELOPED ACROSS
NORTHERN PORTIONS OF THE FORECAST AREA THIS AFTERNOON WITHIN THE
STRONGEST UPPER LEVEL AND SFC FORCING...WITH A FEW UPDRAFTS
SPIKING ABOVE 20KFT WITH THE HELP OF 500 TO 1000 J/KG OF MLCAPE.
MAINTAINED MENTION IN THE FORECAST FOR GUSTY WINDS AND SMALL HAIL
WITH THIS ACTIVITY THROUGH THE LATE AFTERNOON. 30 TO 40 KTS OF
BULK SHEAR IS ANALYZED OVER THE NEB PANHANDLE COINCIDENT WITH THE
HIGHER VALUES OF INSTABILITY...SO THE POSSIBILITY DOES EXIST FOR A
FEW STORMS TO BECOME STRONGER AS THEY TREK EAST TOWARD THE
SANDHILLS. WEAKER CONVECTION ALSO DEVELOPED OVER THE MOUNTAINS OF
SOUTHEAST WYOMING AND COLORADO EARLIER...WITH SOME OF THIS ACTIVITY
MOVING OFF THE HIGH TERRAIN AND ALONG THE CHEYENNE RIDGE AS WELL.
WATER VAPOR IMAGERY AND SPC MESOANALYSIS DATA INDICATE A BROADER
AREA OF SUBSIDENCE WAS OVER THIS AREA DURING THIS TIME...AND
LIKELY STUNTED THE GROWTH OF THE CONVECTION WHILE FORCING SOME
STRONGER WIND GUSTS AROUND 50 MPH TO THE SFC. A FEW SHOWERS
CONTINUE TO DEVELOP OVER MOUNTAINS AT THIS HOUR...BUT EXPECT A
SIMILAR TREND FOR WEAK BUT GUSTY SHOWERS AS DRIER AIR AND SOME
UPPER LEVEL SUBSIDENCE REMAIN IN PLACE HERE.

THE FRONT WILL CONTINUE TO MOVE SOUTH ACROSS EASTERN COUNTIES
THROUGH THIS EVENING WHILE DRIER AIR MOVES OVERHEAD AND SUBSIDENCE
BECOMES MORE WIDESPREAD. THUS EXPECT ACTIVITY TO COME TO AN END
QUICKLY AROUND SUNSET. ANOTHER SHORTWAVE WILL MOVE OVERHEAD TOMORROW
AFTERNOON...ALTHOUGH A MUCH DRIER AIRMASS WILL BE IN PLACE WHICH
WILL MINIMIZE COVERAGE OF SHOWERS AND STORMS. THE FOCUS FOR ACTIVITY
WILL BE ACROSS THE NORTHERN ZONES ONCE AGAIN ON THE LEADING EDGE OF
ANOTHER BACKDOOR COLD FRONT MOVING WITH THE UPPER WAVE. A FEW STORMS
COULD BECOME STRONG IN THIS AREA AS 30 KTS OF SHEAR IS PROGGED BY
THE NAM HERE. THE ONE LIMITING FACTOR WILL BE AVAILABLE INSTABILITY AS
MODELS DEVELOP ONLY ABOUT 500 J/KG OF CAPE BY THE AFTERNOON.
CANNOT RULE OUT A FEW WEAKER SHOWERS/STORMS DEVELOPING AND MOVING
OFF THE LARAMIE RANGE AS WELL IN THE LATE AFTERNOON BUT THESE WILL
BE WEAK AND VERY ISOLATED.

DRY ZONAL FLOW WILL THEN TAKE AHOLD OF THE FORECAST AREA FOR
TUESDAY...WITH TEMPS WARMING BACK TO MORE NORMAL VALUES FOR THIS
TIME OF YEAR. HUMIDITIES LOOK TO DROP INTO THE TEENS AND 20S FOR
MUCH OF THE AREA...WHILE  WINDS WILL CONTINUE TO BE GUSTY ALONG AND
WEST OF THE LARAMIE RANGE. WILL CONTINUE TO MONITOR TUESDAY FOR
ELEVATED FIRE WEATHER CONCERNS.

.LONG TERM...(WEDNESDAY THROUGH SATURDAY)
ISSUED AT 345 PM MDT SUN AUG 31 2014

WEDNESDAY WILL BE THE WARMEST DAY OF THE EXTENDED PERIOD WITH
SOUTHWESTERLY FLOW ALOFT AND A LEE TROUGH AT THE SFC.  700MB TEMPS
WILL RISE TO 16C WITH AROUND 30C AT 850MB.  HIGHS OVER THE PLAINS
WILL BE IN THE UPPER 80S TO LOW 90S...WHICH IS 5-10 DEGREES ABOVE
NORMAL FOR EARLY SEPTEMBER.  MAY HAVE TO DEAL WITH SOME FIRE WEATHER
CONCERNS OVER SOUTHEAST WY AS MIN RH VALUES DROP TO AROUND 15
PERCENT AND WINDS WILL BE BREEZY...ESPECIALLY TO THE WEST OF THE
LARAMIE RANGE.  UPPER LEVEL WAVE PUSHES FROM THE NORTHERN ROCKIES ON
WED TOWARD NORTH DAKOTA ON THURS.  THIS WILL PUSH A COLD FRONT
THROUGH THE CWA ON THURS MORNING WITH 10-15 DEGREES OF COOLING.  IT
IS GENERALLY A DRY FRONTAL PASSAGE...AT LEAST INITIALLY.  BY THURS
NIGHT INTO FRI THIS COULD CHANGE AS ISENTROPIC LIFT COMBINES WITH
IMPROVING JET DYNAMICS SUCH THAT SCATTERED SHOWERS DEVELOP OVER
PORTIONS OF THE CWA.  THE ECMWF HAS WIDESPREAD SHOWERS ON THURS
NIGHT WHEREAS THE GFS HAS THIS AREA FURTHER SOUTH OVER NORTHERN
COLORADO.  LLVL SOUTHEASTERLY UPSLOPE WILL CONTINUE THROUGH SATURDAY
WITH WEAK SHORTWAVES MOVING ACROSS THE REGION FROM THE SOUTHWEST.
SEEMS LIKE A FAVORABLE PATTERN FOR AT LEAST ISOLATED TO SCATTERED
SHOWERS AT TIMES ALONG WITH INCREASED CLOUD COVER AND GENERALLY HAVE
SLIGHT CHANCE POPS ON FRI AND SAT.  INSTABILITY IS QUITE LIMITED
THROUGH FRI...THEN IMPROVES SOME BY SAT (CAPE VALUES INCREASE TO
500-750 J/KG).

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY EVENING)
ISSUED AT 1041 PM MDT SUN AUG 31 2014

VFR CONDITIONS EXPECTED OVERNIGHT INTO MONDAY. WINDS WILL BEGIN TO
PICK UP AFTER 16Z FOR OUR SOUTHEAST WYOMING AIRPORTS.
OTHERWISE...NO WEATHER IMAPCTS TO AVIATION INTERESTS.

&&

.FIRE WEATHER...
ISSUED AT 345 PM MDT SUN AUG 31 2014

SCATTERED SHOWERS AND T-STORMS WILL CONTINUE OVER THE DISTRICT
THROUGH EARLY THIS EVENING BEFORE COMING TO AN END TONIGHT. LIGHT
TO MODERATE RAIN...GUSTY DOWNDRAFT WINDS...AND OCCASIONAL
LIGHTNING WILL ACCOMPANY THE STORMS. A WEAK DISTURBANCE MOVING
OVERHEAD ON MONDAY WILL BRING A CHANCE FOR MORE ISOLATED SHOWERS
AND STORMS MAINLY OVER NORTHERN AND EASTERN PORTIONS OF THE
DISTRICT IN THE AFTERNOON. LIGHT RAINFALL AND GUSTY WINDS WILL
REMAIN A POSSIBILITY WITH THIS ACTIVITY. A MUCH DRIER AIRMASS WILL
MOVE OVERHEAD TUESDAY AND WILL REMAIN IN PLACE THROUGH WEDNESDAY.
TEMPERATURES WILL WARM BACK TO ABOVE NORMAL READINGS BY
WEDNESDAY AS WELL...WHILE WEST TO SOUTHWEST WINDS WILL REMAIN
GUSTY IN AREAS ALONG AND WEST OF THE LARAMIE RANGE.

&&

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

$$

UPDATE...HAMMER
SHORT TERM...RJM
LONG TERM...FINCH
AVIATION...CLAYCOMB
FIRE WEATHER...RJM








000
FXUS65 KCYS 010444
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
1044 PM MDT SUN AUG 31 2014

.UPDATE...
ISSUED AT 816 PM MDT SUN AUG 31 2014

SHOWER AND TSTM ACTIVITY HAS GREATLY DIMINISHED ACROSS THE AREA
THIS EVE. SFC OBSERVATIONS INDICATE THE COLD FRONT HAS MOVED TO
THE SOUTHEAST OF THE CWA WITH DRYING/SUBSIDENCE OCCURRING IN ITS
WAKE. RADAR IS CLEAR OVER OUR ZONES AS OF 02Z AND WOULD EXPECT
LITTLE ADDITIONAL DEVELOPMENT TONIGHT AS WATER VAPOR SATELLITE
SHOWS THE MAIN SHORT WAVE AXIS MOVING EASTWARD INTO CENTRAL NE.
KEPT ISOLATED POPS IN THE PANHANDLE THROUGH 03Z AS SOME MID AND
HIGH LEVEL MOISTURE LINGERS. DRY OVERNIGHT WITH SUBSIDING MOTION
ALOFT. ADJUSTED CLOUD TRENDS TO SHOW MORE CLEARING OVERNIGHT AND
THEN INCREASING AGAIN AROUND SUNRISE MON WITH THE NEXT PIECE OF
SHORTWAVE ENERGY CURRENTLY OVER THE INTERMOUNTAIN WEST.

SHORT TERM...(THIS EVENING THROUGH TUESDAY NIGHT)
ISSUED AT 345 PM MDT SUN AUG 31 2014

WATER VAPOR IMAGERY THIS AFTERNOON SHOWS THE UPPER LEVEL SHORTWAVE
MOVING OVER THE FORECAST AREA WITHIN THE LEFT EXIT REGION OF A 100
KT JET. AS OF 3 PM...THE SFC COLD FRONT LOOKS TO EXTEND ROUGHLY
FROM SOUTHEAST NIOBRARA COUNTY...THROUGH CONVERSE COUNTY...AND
WESTWARD THROUGH NATRONA COUNTY AND IS STEADILY MOVING SOUTH.
SCATTERED TO NUMEROUS SHOWERS AND T-STORMS HAVE DEVELOPED ACROSS
NORTHERN PORTIONS OF THE FORECAST AREA THIS AFTERNOON WITHIN THE
STRONGEST UPPER LEVEL AND SFC FORCING...WITH A FEW UPDRAFTS
SPIKING ABOVE 20KFT WITH THE HELP OF 500 TO 1000 J/KG OF MLCAPE.
MAINTAINED MENTION IN THE FORECAST FOR GUSTY WINDS AND SMALL HAIL
WITH THIS ACTIVITY THROUGH THE LATE AFTERNOON. 30 TO 40 KTS OF
BULK SHEAR IS ANALYZED OVER THE NEB PANHANDLE COINCIDENT WITH THE
HIGHER VALUES OF INSTABILITY...SO THE POSSIBILITY DOES EXIST FOR A
FEW STORMS TO BECOME STRONGER AS THEY TREK EAST TOWARD THE
SANDHILLS. WEAKER CONVECTION ALSO DEVELOPED OVER THE MOUNTAINS OF
SOUTHEAST WYOMING AND COLORADO EARLIER...WITH SOME OF THIS ACTIVITY
MOVING OFF THE HIGH TERRAIN AND ALONG THE CHEYENNE RIDGE AS WELL.
WATER VAPOR IMAGERY AND SPC MESOANALYSIS DATA INDICATE A BROADER
AREA OF SUBSIDENCE WAS OVER THIS AREA DURING THIS TIME...AND
LIKELY STUNTED THE GROWTH OF THE CONVECTION WHILE FORCING SOME
STRONGER WIND GUSTS AROUND 50 MPH TO THE SFC. A FEW SHOWERS
CONTINUE TO DEVELOP OVER MOUNTAINS AT THIS HOUR...BUT EXPECT A
SIMILAR TREND FOR WEAK BUT GUSTY SHOWERS AS DRIER AIR AND SOME
UPPER LEVEL SUBSIDENCE REMAIN IN PLACE HERE.

THE FRONT WILL CONTINUE TO MOVE SOUTH ACROSS EASTERN COUNTIES
THROUGH THIS EVENING WHILE DRIER AIR MOVES OVERHEAD AND SUBSIDENCE
BECOMES MORE WIDESPREAD. THUS EXPECT ACTIVITY TO COME TO AN END
QUICKLY AROUND SUNSET. ANOTHER SHORTWAVE WILL MOVE OVERHEAD TOMORROW
AFTERNOON...ALTHOUGH A MUCH DRIER AIRMASS WILL BE IN PLACE WHICH
WILL MINIMIZE COVERAGE OF SHOWERS AND STORMS. THE FOCUS FOR ACTIVITY
WILL BE ACROSS THE NORTHERN ZONES ONCE AGAIN ON THE LEADING EDGE OF
ANOTHER BACKDOOR COLD FRONT MOVING WITH THE UPPER WAVE. A FEW STORMS
COULD BECOME STRONG IN THIS AREA AS 30 KTS OF SHEAR IS PROGGED BY
THE NAM HERE. THE ONE LIMITING FACTOR WILL BE AVAILABLE INSTABILITY AS
MODELS DEVELOP ONLY ABOUT 500 J/KG OF CAPE BY THE AFTERNOON.
CANNOT RULE OUT A FEW WEAKER SHOWERS/STORMS DEVELOPING AND MOVING
OFF THE LARAMIE RANGE AS WELL IN THE LATE AFTERNOON BUT THESE WILL
BE WEAK AND VERY ISOLATED.

DRY ZONAL FLOW WILL THEN TAKE AHOLD OF THE FORECAST AREA FOR
TUESDAY...WITH TEMPS WARMING BACK TO MORE NORMAL VALUES FOR THIS
TIME OF YEAR. HUMIDITIES LOOK TO DROP INTO THE TEENS AND 20S FOR
MUCH OF THE AREA...WHILE  WINDS WILL CONTINUE TO BE GUSTY ALONG AND
WEST OF THE LARAMIE RANGE. WILL CONTINUE TO MONITOR TUESDAY FOR
ELEVATED FIRE WEATHER CONCERNS.

.LONG TERM...(WEDNESDAY THROUGH SATURDAY)
ISSUED AT 345 PM MDT SUN AUG 31 2014

WEDNESDAY WILL BE THE WARMEST DAY OF THE EXTENDED PERIOD WITH
SOUTHWESTERLY FLOW ALOFT AND A LEE TROUGH AT THE SFC.  700MB TEMPS
WILL RISE TO 16C WITH AROUND 30C AT 850MB.  HIGHS OVER THE PLAINS
WILL BE IN THE UPPER 80S TO LOW 90S...WHICH IS 5-10 DEGREES ABOVE
NORMAL FOR EARLY SEPTEMBER.  MAY HAVE TO DEAL WITH SOME FIRE WEATHER
CONCERNS OVER SOUTHEAST WY AS MIN RH VALUES DROP TO AROUND 15
PERCENT AND WINDS WILL BE BREEZY...ESPECIALLY TO THE WEST OF THE
LARAMIE RANGE.  UPPER LEVEL WAVE PUSHES FROM THE NORTHERN ROCKIES ON
WED TOWARD NORTH DAKOTA ON THURS.  THIS WILL PUSH A COLD FRONT
THROUGH THE CWA ON THURS MORNING WITH 10-15 DEGREES OF COOLING.  IT
IS GENERALLY A DRY FRONTAL PASSAGE...AT LEAST INITIALLY.  BY THURS
NIGHT INTO FRI THIS COULD CHANGE AS ISENTROPIC LIFT COMBINES WITH
IMPROVING JET DYNAMICS SUCH THAT SCATTERED SHOWERS DEVELOP OVER
PORTIONS OF THE CWA.  THE ECMWF HAS WIDESPREAD SHOWERS ON THURS
NIGHT WHEREAS THE GFS HAS THIS AREA FURTHER SOUTH OVER NORTHERN
COLORADO.  LLVL SOUTHEASTERLY UPSLOPE WILL CONTINUE THROUGH SATURDAY
WITH WEAK SHORTWAVES MOVING ACROSS THE REGION FROM THE SOUTHWEST.
SEEMS LIKE A FAVORABLE PATTERN FOR AT LEAST ISOLATED TO SCATTERED
SHOWERS AT TIMES ALONG WITH INCREASED CLOUD COVER AND GENERALLY HAVE
SLIGHT CHANCE POPS ON FRI AND SAT.  INSTABILITY IS QUITE LIMITED
THROUGH FRI...THEN IMPROVES SOME BY SAT (CAPE VALUES INCREASE TO
500-750 J/KG).

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY EVENING)
ISSUED AT 1041 PM MDT SUN AUG 31 2014

VFR CONDITIONS EXPECTED OVERNIGHT INTO MONDAY. WINDS WILL BEGIN TO
PICK UP AFTER 16Z FOR OUR SOUTHEAST WYOMING AIRPORTS.
OTHERWISE...NO WEATHER IMAPCTS TO AVIATION INTERESTS.

&&

.FIRE WEATHER...
ISSUED AT 345 PM MDT SUN AUG 31 2014

SCATTERED SHOWERS AND T-STORMS WILL CONTINUE OVER THE DISTRICT
THROUGH EARLY THIS EVENING BEFORE COMING TO AN END TONIGHT. LIGHT
TO MODERATE RAIN...GUSTY DOWNDRAFT WINDS...AND OCCASIONAL
LIGHTNING WILL ACCOMPANY THE STORMS. A WEAK DISTURBANCE MOVING
OVERHEAD ON MONDAY WILL BRING A CHANCE FOR MORE ISOLATED SHOWERS
AND STORMS MAINLY OVER NORTHERN AND EASTERN PORTIONS OF THE
DISTRICT IN THE AFTERNOON. LIGHT RAINFALL AND GUSTY WINDS WILL
REMAIN A POSSIBILITY WITH THIS ACTIVITY. A MUCH DRIER AIRMASS WILL
MOVE OVERHEAD TUESDAY AND WILL REMAIN IN PLACE THROUGH WEDNESDAY.
TEMPERATURES WILL WARM BACK TO ABOVE NORMAL READINGS BY
WEDNESDAY AS WELL...WHILE WEST TO SOUTHWEST WINDS WILL REMAIN
GUSTY IN AREAS ALONG AND WEST OF THE LARAMIE RANGE.

&&

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

$$

UPDATE...HAMMER
SHORT TERM...RJM
LONG TERM...FINCH
AVIATION...CLAYCOMB
FIRE WEATHER...RJM








000
FXUS65 KCYS 010228
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
828 PM MDT SUN AUG 31 2014

.UPDATE...
ISSUED AT 816 PM MDT SUN AUG 31 2014

SHOWER AND TSTM ACTIVITY HAS GREATLY DIMINISHED ACROSS THE AREA
THIS EVE. SFC OBSERVATIONS INDICATE THE COLD FRONT HAS MOVED TO
THE SOUTHEAST OF THE CWA WITH DRYING/SUBSIDENCE OCCURRING IN ITS
WAKE. RADAR IS CLEAR OVER OUR ZONES AS OF 02Z AND WOULD EXPECT
LITTLE ADDITIONAL DEVELOPMENT TONIGHT AS WATER VAPOR SATELLITE
SHOWS THE MAIN SHORT WAVE AXIS MOVING EASTWARD INTO CENTRAL NE.
KEPT ISOLATED POPS IN THE PANHANDLE THROUGH 03Z AS SOME MID AND
HIGH LEVEL MOISTURE LINGERS. DRY OVERNIGHT WITH SUBSIDING MOTION
ALOFT. ADJUSTED CLOUD TRENDS TO SHOW MORE CLEARING OVERNIGHT AND
THEN INCREASING AGAIN AROUND SUNRISE MON WITH THE NEXT PIECE OF
SHORTWAVE ENERGY CURRENTLY OVER THE INTERMOUNTAIN WEST.

SHORT TERM...(THIS EVENING THROUGH TUESDAY NIGHT)
ISSUED AT 345 PM MDT SUN AUG 31 2014

WATER VAPOR IMAGERY THIS AFTERNOON SHOWS THE UPPER LEVEL SHORTWAVE
MOVING OVER THE FORECAST AREA WITHIN THE LEFT EXIT REGION OF A 100
KT JET. AS OF 3 PM...THE SFC COLD FRONT LOOKS TO EXTEND ROUGHLY
FROM SOUTHEAST NIOBRARA COUNTY...THROUGH CONVERSE COUNTY...AND
WESTWARD THROUGH NATRONA COUNTY AND IS STEADILY MOVING SOUTH.
SCATTERED TO NUMEROUS SHOWERS AND T-STORMS HAVE DEVELOPED ACROSS
NORTHERN PORTIONS OF THE FORECAST AREA THIS AFTERNOON WITHIN THE
STRONGEST UPPER LEVEL AND SFC FORCING...WITH A FEW UPDRAFTS
SPIKING ABOVE 20KFT WITH THE HELP OF 500 TO 1000 J/KG OF MLCAPE.
MAINTAINED MENTION IN THE FORECAST FOR GUSTY WINDS AND SMALL HAIL
WITH THIS ACTIVITY THROUGH THE LATE AFTERNOON. 30 TO 40 KTS OF
BULK SHEAR IS ANALYZED OVER THE NEB PANHANDLE COINCIDENT WITH THE
HIGHER VALUES OF INSTABILITY...SO THE POSSIBILITY DOES EXIST FOR A
FEW STORMS TO BECOME STRONGER AS THEY TREK EAST TOWARD THE
SANDHILLS. WEAKER CONVECTION ALSO DEVELOPED OVER THE MOUNTAINS OF
SOUTHEAST WYOMING AND COLORADO EARLIER...WITH SOME OF THIS ACTIVITY
MOVING OFF THE HIGH TERRAIN AND ALONG THE CHEYENNE RIDGE AS WELL.
WATER VAPOR IMAGERY AND SPC MESOANALYSIS DATA INDICATE A BROADER
AREA OF SUBSIDENCE WAS OVER THIS AREA DURING THIS TIME...AND
LIKELY STUNTED THE GROWTH OF THE CONVECTION WHILE FORCING SOME
STRONGER WIND GUSTS AROUND 50 MPH TO THE SFC. A FEW SHOWERS
CONTINUE TO DEVELOP OVER MOUNTAINS AT THIS HOUR...BUT EXPECT A
SIMILAR TREND FOR WEAK BUT GUSTY SHOWERS AS DRIER AIR AND SOME
UPPER LEVEL SUBSIDENCE REMAIN IN PLACE HERE.

THE FRONT WILL CONTINUE TO MOVE SOUTH ACROSS EASTERN COUNTIES
THROUGH THIS EVENING WHILE DRIER AIR MOVES OVERHEAD AND SUBSIDENCE
BECOMES MORE WIDESPREAD. THUS EXPECT ACTIVITY TO COME TO AN END
QUICKLY AROUND SUNSET. ANOTHER SHORTWAVE WILL MOVE OVERHEAD TOMORROW
AFTERNOON...ALTHOUGH A MUCH DRIER AIRMASS WILL BE IN PLACE WHICH
WILL MINIMIZE COVERAGE OF SHOWERS AND STORMS. THE FOCUS FOR ACTIVITY
WILL BE ACROSS THE NORTHERN ZONES ONCE AGAIN ON THE LEADING EDGE OF
ANOTHER BACKDOOR COLD FRONT MOVING WITH THE UPPER WAVE. A FEW STORMS
COULD BECOME STRONG IN THIS AREA AS 30 KTS OF SHEAR IS PROGGED BY
THE NAM HERE. THE ONE LIMITING FACTOR WILL BE AVAILABLE INSTABILITY AS
MODELS DEVELOP ONLY ABOUT 500 J/KG OF CAPE BY THE AFTERNOON.
CANNOT RULE OUT A FEW WEAKER SHOWERS/STORMS DEVELOPING AND MOVING
OFF THE LARAMIE RANGE AS WELL IN THE LATE AFTERNOON BUT THESE WILL
BE WEAK AND VERY ISOLATED.

DRY ZONAL FLOW WILL THEN TAKE AHOLD OF THE FORECAST AREA FOR
TUESDAY...WITH TEMPS WARMING BACK TO MORE NORMAL VALUES FOR THIS
TIME OF YEAR. HUMIDITIES LOOK TO DROP INTO THE TEENS AND 20S FOR
MUCH OF THE AREA...WHILE  WINDS WILL CONTINUE TO BE GUSTY ALONG AND
WEST OF THE LARAMIE RANGE. WILL CONTINUE TO MONITOR TUESDAY FOR
ELEVATED FIRE WEATHER CONCERNS.

.LONG TERM...(WEDNESDAY THROUGH SATURDAY)
ISSUED AT 345 PM MDT SUN AUG 31 2014

WEDNESDAY WILL BE THE WARMEST DAY OF THE EXTENDED PERIOD WITH
SOUTHWESTERLY FLOW ALOFT AND A LEE TROUGH AT THE SFC.  700MB TEMPS
WILL RISE TO 16C WITH AROUND 30C AT 850MB.  HIGHS OVER THE PLAINS
WILL BE IN THE UPPER 80S TO LOW 90S...WHICH IS 5-10 DEGREES ABOVE
NORMAL FOR EARLY SEPTEMBER.  MAY HAVE TO DEAL WITH SOME FIRE WEATHER
CONCERNS OVER SOUTHEAST WY AS MIN RH VALUES DROP TO AROUND 15
PERCENT AND WINDS WILL BE BREEZY...ESPECIALLY TO THE WEST OF THE
LARAMIE RANGE.  UPPER LEVEL WAVE PUSHES FROM THE NORTHERN ROCKIES ON
WED TOWARD NORTH DAKOTA ON THURS.  THIS WILL PUSH A COLD FRONT
THROUGH THE CWA ON THURS MORNING WITH 10-15 DEGREES OF COOLING.  IT
IS GENERALLY A DRY FRONTAL PASSAGE...AT LEAST INITIALLY.  BY THURS
NIGHT INTO FRI THIS COULD CHANGE AS ISENTROPIC LIFT COMBINES WITH
IMPROVING JET DYNAMICS SUCH THAT SCATTERED SHOWERS DEVELOP OVER
PORTIONS OF THE CWA.  THE ECMWF HAS WIDESPREAD SHOWERS ON THURS
NIGHT WHEREAS THE GFS HAS THIS AREA FURTHER SOUTH OVER NORTHERN
COLORADO.  LLVL SOUTHEASTERLY UPSLOPE WILL CONTINUE THROUGH SATURDAY
WITH WEAK SHORTWAVES MOVING ACROSS THE REGION FROM THE SOUTHWEST.
SEEMS LIKE A FAVORABLE PATTERN FOR AT LEAST ISOLATED TO SCATTERED
SHOWERS AT TIMES ALONG WITH INCREASED CLOUD COVER AND GENERALLY HAVE
SLIGHT CHANCE POPS ON FRI AND SAT.  INSTABILITY IS QUITE LIMITED
THROUGH FRI...THEN IMPROVES SOME BY SAT (CAPE VALUES INCREASE TO
500-750 J/KG).

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY AFTERNOON)
ISSUED AT 505 PM MDT SUN AUG 31 2014

MAINLY VFR FOR TONIGHT INO MONDAY AS WESTERLY DOWNSLOPING WINDS
WILL BE IN PLACE. RADAR TRENDS ARE SHOWING CONVECTION ACROSS
NIOBRARA COUNTY INTO THE NORTHERN PANHANDLE. THIS SHOULD COME TO
AN END BY SUNSET. WESTERLY WINS RETURN MONDAY AFTERNOON AND WILL
GUST INTO THE 20KT RANGE ONCE AGAIN.


&&

.FIRE WEATHER...
ISSUED AT 345 PM MDT SUN AUG 31 2014

SCATTERED SHOWERS AND T-STORMS WILL CONTINUE OVER THE DISTRICT
THROUGH EARLY THIS EVENING BEFORE COMING TO AN END TONIGHT. LIGHT
TO MODERATE RAIN...GUSTY DOWNDRAFT WINDS...AND OCCASIONAL
LIGHTNING WILL ACCOMPANY THE STORMS. A WEAK DISTURBANCE MOVING
OVERHEAD ON MONDAY WILL BRING A CHANCE FOR MORE ISOLATED SHOWERS
AND STORMS MAINLY OVER NORTHERN AND EASTERN PORTIONS OF THE
DISTRICT IN THE AFTERNOON. LIGHT RAINFALL AND GUSTY WINDS WILL
REMAIN A POSSIBILITY WITH THIS ACTIVITY. A MUCH DRIER AIRMASS WILL
MOVE OVERHEAD TUESDAY AND WILL REMAIN IN PLACE THROUGH WEDNESDAY.
TEMPERATURES WILL WARM BACK TO ABOVE NORMAL READINGS BY
WEDNESDAY AS WELL...WHILE WEST TO SOUTHWEST WINDS WILL REMAIN
GUSTY IN AREAS ALONG AND WEST OF THE LARAMIE RANGE.

&&

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

$$

UPDATE...HAMMER
SHORT TERM...RJM
LONG TERM...FINCH
AVIATION...CLAYCOMB
FIRE WEATHER...RJM







000
FXUS63 KUNR 010020
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
620 PM MDT SUN AUG 31 2014

.SHORT TERM...THIS EVENING THROUGH MONDAY NIGHT
ISSUED AT 300 PM MDT SUN AUG 31 2014

CURRENT SURFACE ANALYSIS SHOWS LOW PRESSURE OVER NORTHWEST
MN...WITH COLD FRONT WELL EAST OF OUR FORECAST AREA. UPPER LEVEL
ANALYSIS SHOWS BROAD TROF OVER THE WESTERN CONUS...WITH A SERIES
OF SHORTWAVES WITHIN THE TROF MOVING EAST THROUGH THE ROCKIES AND
PLAINS. LAST NIGHTS WAVE HAS MOVED WELL EAST OF THE AREA...WHILE
THE NEXT ONE IS MOVING QUICKLY ACROSS EASTERN WY INTO WESTERN SD
AND WESTERN NEB. KUDX RADAR SHOWS NUMEROUS SHOWERS AND
THUNDERSTORMS OVER MUCH OF NORTHEAST WY AND WESTERN SD...WITH THE
HEAVIEST ACTIVITY GENERALLY OVER AND AROUND THE BLACK HILLS. TEMPS
ARE IN THE 60S TO MID 70S WITH NORTHERLY WINDS IN MOST AREAS.

THE UNSETTLED WEATHER PATTERN WILL CONTINUE THROUGH LABOR DAY AS
THIS LATEST DISTURBANCE EXITS THIS EVENING AND THE NEXT ONE PUSHES
THROUGH ON MONDAY. A BREAK IN THE PATTERN CAN BE EXPECTED FOR
TUESDAY AND WEDNESDAY.

FOR LATE TODAY AND TONIGHT...SHOWERS AND THUNDERSTORMS WILL CONTINUE
TO TRACK EAST ACROSS THE AREA...ENDING ACROSS NORTHEAST WY BY EARLY
EVENING AND FROM WEST TO EAST ACROSS WESTERN SD DURING THE EVENING.
THE BEST CHANCES FOR PCPN WILL BE EAST OF THE BLACK HILLS DURING THE
EVENING. SKIES WILL CLEAR OUT BEHIND THE WAVE FOR A WHILE...BUT
CLOUDS WILL INCREASE AGAIN FROM THE WEST LATE TONIGHT INTO MONDAY
MORNING AS THE NEXT DISTURBANCE APPROACHES. WILL KEEP A SLIGHT
CHANCE FOR SHOWERS LATE TONIGHT OVER NORTHEAST WY AND FAR NORTHWEST
SD. A COOL NIGHT IS ON TAP WITH LOWS IN THE MID 40S TO MID
50S...COOLEST OVER THE BLACK HILLS AND USUAL VALLEY LOCATIONS.

ANOTHER COOL DAY CAN BE EXPECTED MONDAY...WITH CHANCES FOR SHOWERS
AND STORMS INCREASING THROUGH THE MORNING AND INTO THE AFTERNOON
FROM WEST TO EAST. SHOWERS WILL LIKELY NOT BE AS NUMEROUS AS
TODAY...BUT SHOULD BE AT LEAST SCATTERED IN COVERAGE ACROSS MOST
AREAS. HIGHS WILL BE IN THE 70S ACROSS MOST OF THE PLAINS...WITH 60S
OVER THE BLACK HILLS. THREAT FOR SEVERE WEATHER WILL AGAIN BE
MINIMAL AT BEST WITH RELATIVELY WEAK INSTABILITY IN PLACE FOR STRONG
STORMS. SHOWERS WILL EXIT THE AREA FROM WEST TO EAST LATE MONDAY AND
MONDAY EVENING.

&&

.LONG TERM...TUESDAY THROUGH SUNDAY
ISSUED AT 300 PM MDT SUN AUG 31 2014

AN UPPER TROUGH WILL DEEPEN OVER THE PACIFIC NORTHWEST
TUESDAY/WEDNESDAY BRINGING A FLAT UPPER RIDGE/THERMAL RIDGE OVER THE
AREA. RESULT WILL BE DRIER WEATHER AND WARMER TEMPERATURES. A
SPIRITED SHORTWAVE WILL PUSH THROUGH THE CWA WEDNESDAY
NIGHT/THURSDAY BRINGING A SHARP COLD FRONT AND LOWER TEMPERATURES
FOR THURSDAY/FRIDAY. SMALL POPS LOOK REASONABLE BEHIND FRONT THROUGH
NEXT WEEKEND GIVEN WEST/NORTHWEST FLOW ALOFT.

&&

.AVIATION...FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING
ISSUED AT 617 PM MDT SUN AUG 31 2014

SCATTERED SHOWERS AND THUNDERSTORMS WILL GRADUALLY END THIS
EVENING. SHOWERS AND THUNDERSTORMS WILL REDEVELOP OVER
NORTHEASTERN WYOMING AND FAR SOUTHWESTERN SOUTH DAKOTA LATE MONDAY
MORNING AND THEN WILL SPREAD ACROSS MUCH OF THE REST OF WESTERN
SOUTH DAKOTA DURING THE AFTERNOON. LOCAL MVFR CIGS/IFR VSBYS ARE POSSIBLE
WITH THE STRONGER SHOWERS/STORMS.

&&

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

$$

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







000
FXUS63 KUNR 010020
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
620 PM MDT SUN AUG 31 2014

.SHORT TERM...THIS EVENING THROUGH MONDAY NIGHT
ISSUED AT 300 PM MDT SUN AUG 31 2014

CURRENT SURFACE ANALYSIS SHOWS LOW PRESSURE OVER NORTHWEST
MN...WITH COLD FRONT WELL EAST OF OUR FORECAST AREA. UPPER LEVEL
ANALYSIS SHOWS BROAD TROF OVER THE WESTERN CONUS...WITH A SERIES
OF SHORTWAVES WITHIN THE TROF MOVING EAST THROUGH THE ROCKIES AND
PLAINS. LAST NIGHTS WAVE HAS MOVED WELL EAST OF THE AREA...WHILE
THE NEXT ONE IS MOVING QUICKLY ACROSS EASTERN WY INTO WESTERN SD
AND WESTERN NEB. KUDX RADAR SHOWS NUMEROUS SHOWERS AND
THUNDERSTORMS OVER MUCH OF NORTHEAST WY AND WESTERN SD...WITH THE
HEAVIEST ACTIVITY GENERALLY OVER AND AROUND THE BLACK HILLS. TEMPS
ARE IN THE 60S TO MID 70S WITH NORTHERLY WINDS IN MOST AREAS.

THE UNSETTLED WEATHER PATTERN WILL CONTINUE THROUGH LABOR DAY AS
THIS LATEST DISTURBANCE EXITS THIS EVENING AND THE NEXT ONE PUSHES
THROUGH ON MONDAY. A BREAK IN THE PATTERN CAN BE EXPECTED FOR
TUESDAY AND WEDNESDAY.

FOR LATE TODAY AND TONIGHT...SHOWERS AND THUNDERSTORMS WILL CONTINUE
TO TRACK EAST ACROSS THE AREA...ENDING ACROSS NORTHEAST WY BY EARLY
EVENING AND FROM WEST TO EAST ACROSS WESTERN SD DURING THE EVENING.
THE BEST CHANCES FOR PCPN WILL BE EAST OF THE BLACK HILLS DURING THE
EVENING. SKIES WILL CLEAR OUT BEHIND THE WAVE FOR A WHILE...BUT
CLOUDS WILL INCREASE AGAIN FROM THE WEST LATE TONIGHT INTO MONDAY
MORNING AS THE NEXT DISTURBANCE APPROACHES. WILL KEEP A SLIGHT
CHANCE FOR SHOWERS LATE TONIGHT OVER NORTHEAST WY AND FAR NORTHWEST
SD. A COOL NIGHT IS ON TAP WITH LOWS IN THE MID 40S TO MID
50S...COOLEST OVER THE BLACK HILLS AND USUAL VALLEY LOCATIONS.

ANOTHER COOL DAY CAN BE EXPECTED MONDAY...WITH CHANCES FOR SHOWERS
AND STORMS INCREASING THROUGH THE MORNING AND INTO THE AFTERNOON
FROM WEST TO EAST. SHOWERS WILL LIKELY NOT BE AS NUMEROUS AS
TODAY...BUT SHOULD BE AT LEAST SCATTERED IN COVERAGE ACROSS MOST
AREAS. HIGHS WILL BE IN THE 70S ACROSS MOST OF THE PLAINS...WITH 60S
OVER THE BLACK HILLS. THREAT FOR SEVERE WEATHER WILL AGAIN BE
MINIMAL AT BEST WITH RELATIVELY WEAK INSTABILITY IN PLACE FOR STRONG
STORMS. SHOWERS WILL EXIT THE AREA FROM WEST TO EAST LATE MONDAY AND
MONDAY EVENING.

&&

.LONG TERM...TUESDAY THROUGH SUNDAY
ISSUED AT 300 PM MDT SUN AUG 31 2014

AN UPPER TROUGH WILL DEEPEN OVER THE PACIFIC NORTHWEST
TUESDAY/WEDNESDAY BRINGING A FLAT UPPER RIDGE/THERMAL RIDGE OVER THE
AREA. RESULT WILL BE DRIER WEATHER AND WARMER TEMPERATURES. A
SPIRITED SHORTWAVE WILL PUSH THROUGH THE CWA WEDNESDAY
NIGHT/THURSDAY BRINGING A SHARP COLD FRONT AND LOWER TEMPERATURES
FOR THURSDAY/FRIDAY. SMALL POPS LOOK REASONABLE BEHIND FRONT THROUGH
NEXT WEEKEND GIVEN WEST/NORTHWEST FLOW ALOFT.

&&

.AVIATION...FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING
ISSUED AT 617 PM MDT SUN AUG 31 2014

SCATTERED SHOWERS AND THUNDERSTORMS WILL GRADUALLY END THIS
EVENING. SHOWERS AND THUNDERSTORMS WILL REDEVELOP OVER
NORTHEASTERN WYOMING AND FAR SOUTHWESTERN SOUTH DAKOTA LATE MONDAY
MORNING AND THEN WILL SPREAD ACROSS MUCH OF THE REST OF WESTERN
SOUTH DAKOTA DURING THE AFTERNOON. LOCAL MVFR CIGS/IFR VSBYS ARE POSSIBLE
WITH THE STRONGER SHOWERS/STORMS.

&&

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

$$

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






000
FXUS65 KCYS 312307
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
507 PM MDT SUN AUG 31 2014

.SHORT TERM...(THIS EVENING THROUGH TUESDAY NIGHT)
ISSUED AT 345 PM MDT SUN AUG 31 2014

WATER VAPOR IMAGERY THIS AFTERNOON SHOWS THE UPPER LEVEL SHORTWAVE
MOVING OVER THE FORECAST AREA WITHIN THE LEFT EXIT REGION OF A 100
KT JET. AS OF 3 PM...THE SFC COLD FRONT LOOKS TO EXTEND ROUGHLY
FROM SOUTHEAST NIOBRARA COUNTY...THROUGH CONVERSE COUNTY...AND
WESTWARD THROUGH NATRONA COUNTY AND IS STEADILY MOVING SOUTH.
SCATTERED TO NUMEROUS SHOWERS AND T-STORMS HAVE DEVELOPED ACROSS
NORTHERN PORTIONS OF THE FORECAST AREA THIS AFTERNOON WITHIN THE
STRONGEST UPPER LEVEL AND SFC FORCING...WITH A FEW UPDRAFTS
SPIKING ABOVE 20KFT WITH THE HELP OF 500 TO 1000 J/KG OF MLCAPE.
MAINTAINED MENTION IN THE FORECAST FOR GUSTY WINDS AND SMALL HAIL
WITH THIS ACTIVITY THROUGH THE LATE AFTERNOON. 30 TO 40 KTS OF
BULK SHEAR IS ANALYZED OVER THE NEB PANHANDLE COINCIDENT WITH THE
HIGHER VALUES OF INSTABILITY...SO THE POSSIBILITY DOES EXIST FOR A
FEW STORMS TO BECOME STRONGER AS THEY TREK EAST TOWARD THE
SANDHILLS. WEAKER CONVECTION ALSO DEVELOPED OVER THE MOUNTAINS OF
SOUTHEAST WYOMING AND COLORADO EARLIER...WITH SOME OF THIS ACTIVITY
MOVING OFF THE HIGH TERRAIN AND ALONG THE CHEYENNE RIDGE AS WELL.
WATER VAPOR IMAGERY AND SPC MESOANALYSIS DATA INDICATE A BROADER
AREA OF SUBSIDENCE WAS OVER THIS AREA DURING THIS TIME...AND
LIKELY STUNTED THE GROWTH OF THE CONVECTION WHILE FORCING SOME
STRONGER WIND GUSTS AROUND 50 MPH TO THE SFC. A FEW SHOWERS
CONTINUE TO DEVELOP OVER MOUNTAINS AT THIS HOUR...BUT EXPECT A
SIMILAR TREND FOR WEAK BUT GUSTY SHOWERS AS DRIER AIR AND SOME
UPPER LEVEL SUBSIDENCE REMAIN IN PLACE HERE.

THE FRONT WILL CONTINUE TO MOVE SOUTH ACROSS EASTERN COUNTIES
THROUGH THIS EVENING WHILE DRIER AIR MOVES OVERHEAD AND SUBSIDENCE
BECOMES MORE WIDESPREAD. THUS EXPECT ACTIVITY TO COME TO AN END
QUICKLY AROUND SUNSET. ANOTHER SHORTWAVE WILL MOVE OVERHEAD TOMORROW
AFTERNOON...ALTHOUGH A MUCH DRIER AIRMASS WILL BE IN PLACE WHICH
WILL MINIMIZE COVERAGE OF SHOWERS AND STORMS. THE FOCUS FOR ACTIVITY
WILL BE ACROSS THE NORTHERN ZONES ONCE AGAIN ON THE LEADING EDGE OF
ANOTHER BACKDOOR COLD FRONT MOVING WITH THE UPPER WAVE. A FEW STORMS
COULD BECOME STRONG IN THIS AREA AS 30 KTS OF SHEAR IS PROGGED BY
THE NAM HERE. THE ONE LIMITING FACTOR WILL BE AVAILABLE INSTABILITY AS
MODELS DEVELOP ONLY ABOUT 500 J/KG OF CAPE BY THE AFTERNOON.
CANNOT RULE OUT A FEW WEAKER SHOWERS/STORMS DEVELOPING AND MOVING
OFF THE LARAMIE RANGE AS WELL IN THE LATE AFTERNOON BUT THESE WILL
BE WEAK AND VERY ISOLATED.

DRY ZONAL FLOW WILL THEN TAKE AHOLD OF THE FORECAST AREA FOR
TUESDAY...WITH TEMPS WARMING BACK TO MORE NORMAL VALUES FOR THIS
TIME OF YEAR. HUMIDITIES LOOK TO DROP INTO THE TEENS AND 20S FOR
MUCH OF THE AREA...WHILE  WINDS WILL CONTINUE TO BE GUSTY ALONG AND
WEST OF THE LARAMIE RANGE. WILL CONTINUE TO MONITOR TUESDAY FOR
ELEVATED FIRE WEATHER CONCERNS.

.LONG TERM...(WEDNESDAY THROUGH SATURDAY)
ISSUED AT 345 PM MDT SUN AUG 31 2014

WEDNESDAY WILL BE THE WARMEST DAY OF THE EXTENDED PERIOD WITH
SOUTHWESTERLY FLOW ALOFT AND A LEE TROUGH AT THE SFC.  700MB TEMPS
WILL RISE TO 16C WITH AROUND 30C AT 850MB.  HIGHS OVER THE PLAINS
WILL BE IN THE UPPER 80S TO LOW 90S...WHICH IS 5-10 DEGREES ABOVE
NORMAL FOR EARLY SEPTEMBER.  MAY HAVE TO DEAL WITH SOME FIRE WEATHER
CONCERNS OVER SOUTHEAST WY AS MIN RH VALUES DROP TO AROUND 15
PERCENT AND WINDS WILL BE BREEZY...ESPECIALLY TO THE WEST OF THE
LARAMIE RANGE.  UPPER LEVEL WAVE PUSHES FROM THE NORTHERN ROCKIES ON
WED TOWARD NORTH DAKOTA ON THURS.  THIS WILL PUSH A COLD FRONT
THROUGH THE CWA ON THURS MORNING WITH 10-15 DEGREES OF COOLING.  IT
IS GENERALLY A DRY FRONTAL PASSAGE...AT LEAST INITIALLY.  BY THURS
NIGHT INTO FRI THIS COULD CHANGE AS ISENTROPIC LIFT COMBINES WITH
IMPROVING JET DYNAMICS SUCH THAT SCATTERED SHOWERS DEVELOP OVER
PORTIONS OF THE CWA.  THE ECMWF HAS WIDESPREAD SHOWERS ON THURS
NIGHT WHEREAS THE GFS HAS THIS AREA FURTHER SOUTH OVER NORTHERN
COLORADO.  LLVL SOUTHEASTERLY UPSLOPE WILL CONTINUE THROUGH SATURDAY
WITH WEAK SHORTWAVES MOVING ACROSS THE REGION FROM THE SOUTHWEST.
SEEMS LIKE A FAVORABLE PATTERN FOR AT LEAST ISOLATED TO SCATTERED
SHOWERS AT TIMES ALONG WITH INCREASED CLOUD COVER AND GENERALLY HAVE
SLIGHT CHANCE POPS ON FRI AND SAT.  INSTABILITY IS QUITE LIMITED
THROUGH FRI...THEN IMPROVES SOME BY SAT (CAPE VALUES INCREASE TO
500-750 J/KG).

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY AFTERNOON)
ISSUED AT 505 PM MDT SUN AUG 31 2014

MAINLY VFR FOR TONIGHT INO MONDAY AS WESTERLY DOWNSLOPING WINDS
WILL BE IN PLACE. RADAR TRENDS ARE SHOWING CONVECTION ACROSS
NIOBRARA COUNTY INTO THE NORTHERN PANHANDLE. THIS SHOULD COME TO
AN END BY SUNSET. WESTERLY WINS RETURN MONDAY AFTERNOON AND WILL
GUST INTO THE 20KT RANGE ONCE AGAIN.

&&

.FIRE WEATHER...
ISSUED AT 345 PM MDT SUN AUG 31 2014

SCATTERED SHOWERS AND T-STORMS WILL CONTINUE OVER THE DISTRICT
THROUGH EARLY THIS EVENING BEFORE COMING TO AN END TONIGHT. LIGHT
TO MODERATE RAIN...GUSTY DOWNDRAFT WINDS...AND OCCASIONAL
LIGHTNING WILL ACCOMPANY THE STORMS. A WEAK DISTURBANCE MOVING
OVERHEAD ON MONDAY WILL BRING A CHANCE FOR MORE ISOLATED SHOWERS
AND STORMS MAINLY OVER NORTHERN AND EASTERN PORTIONS OF THE
DISTRICT IN THE AFTERNOON. LIGHT RAINFALL AND GUSTY WINDS WILL
REMAIN A POSSIBILITY WITH THIS ACTIVITY. A MUCH DRIER AIRMASS WILL
MOVE OVERHEAD TUESDAY AND WILL REMAIN IN PLACE THROUGH WEDNESDAY.
TEMPERATURES WILL WARM BACK TO ABOVE NORMAL READINGS BY
WEDNESDAY AS WELL...WHILE WEST TO SOUTHWEST WINDS WILL REMAIN
GUSTY IN AREAS ALONG AND WEST OF THE LARAMIE RANGE.

&&

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

$$

SHORT TERM...RJM
LONG TERM...FINCH
AVIATION...CLAYCOMB
FIRE WEATHER...RJM







000
FXUS65 KCYS 312307
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
507 PM MDT SUN AUG 31 2014

.SHORT TERM...(THIS EVENING THROUGH TUESDAY NIGHT)
ISSUED AT 345 PM MDT SUN AUG 31 2014

WATER VAPOR IMAGERY THIS AFTERNOON SHOWS THE UPPER LEVEL SHORTWAVE
MOVING OVER THE FORECAST AREA WITHIN THE LEFT EXIT REGION OF A 100
KT JET. AS OF 3 PM...THE SFC COLD FRONT LOOKS TO EXTEND ROUGHLY
FROM SOUTHEAST NIOBRARA COUNTY...THROUGH CONVERSE COUNTY...AND
WESTWARD THROUGH NATRONA COUNTY AND IS STEADILY MOVING SOUTH.
SCATTERED TO NUMEROUS SHOWERS AND T-STORMS HAVE DEVELOPED ACROSS
NORTHERN PORTIONS OF THE FORECAST AREA THIS AFTERNOON WITHIN THE
STRONGEST UPPER LEVEL AND SFC FORCING...WITH A FEW UPDRAFTS
SPIKING ABOVE 20KFT WITH THE HELP OF 500 TO 1000 J/KG OF MLCAPE.
MAINTAINED MENTION IN THE FORECAST FOR GUSTY WINDS AND SMALL HAIL
WITH THIS ACTIVITY THROUGH THE LATE AFTERNOON. 30 TO 40 KTS OF
BULK SHEAR IS ANALYZED OVER THE NEB PANHANDLE COINCIDENT WITH THE
HIGHER VALUES OF INSTABILITY...SO THE POSSIBILITY DOES EXIST FOR A
FEW STORMS TO BECOME STRONGER AS THEY TREK EAST TOWARD THE
SANDHILLS. WEAKER CONVECTION ALSO DEVELOPED OVER THE MOUNTAINS OF
SOUTHEAST WYOMING AND COLORADO EARLIER...WITH SOME OF THIS ACTIVITY
MOVING OFF THE HIGH TERRAIN AND ALONG THE CHEYENNE RIDGE AS WELL.
WATER VAPOR IMAGERY AND SPC MESOANALYSIS DATA INDICATE A BROADER
AREA OF SUBSIDENCE WAS OVER THIS AREA DURING THIS TIME...AND
LIKELY STUNTED THE GROWTH OF THE CONVECTION WHILE FORCING SOME
STRONGER WIND GUSTS AROUND 50 MPH TO THE SFC. A FEW SHOWERS
CONTINUE TO DEVELOP OVER MOUNTAINS AT THIS HOUR...BUT EXPECT A
SIMILAR TREND FOR WEAK BUT GUSTY SHOWERS AS DRIER AIR AND SOME
UPPER LEVEL SUBSIDENCE REMAIN IN PLACE HERE.

THE FRONT WILL CONTINUE TO MOVE SOUTH ACROSS EASTERN COUNTIES
THROUGH THIS EVENING WHILE DRIER AIR MOVES OVERHEAD AND SUBSIDENCE
BECOMES MORE WIDESPREAD. THUS EXPECT ACTIVITY TO COME TO AN END
QUICKLY AROUND SUNSET. ANOTHER SHORTWAVE WILL MOVE OVERHEAD TOMORROW
AFTERNOON...ALTHOUGH A MUCH DRIER AIRMASS WILL BE IN PLACE WHICH
WILL MINIMIZE COVERAGE OF SHOWERS AND STORMS. THE FOCUS FOR ACTIVITY
WILL BE ACROSS THE NORTHERN ZONES ONCE AGAIN ON THE LEADING EDGE OF
ANOTHER BACKDOOR COLD FRONT MOVING WITH THE UPPER WAVE. A FEW STORMS
COULD BECOME STRONG IN THIS AREA AS 30 KTS OF SHEAR IS PROGGED BY
THE NAM HERE. THE ONE LIMITING FACTOR WILL BE AVAILABLE INSTABILITY AS
MODELS DEVELOP ONLY ABOUT 500 J/KG OF CAPE BY THE AFTERNOON.
CANNOT RULE OUT A FEW WEAKER SHOWERS/STORMS DEVELOPING AND MOVING
OFF THE LARAMIE RANGE AS WELL IN THE LATE AFTERNOON BUT THESE WILL
BE WEAK AND VERY ISOLATED.

DRY ZONAL FLOW WILL THEN TAKE AHOLD OF THE FORECAST AREA FOR
TUESDAY...WITH TEMPS WARMING BACK TO MORE NORMAL VALUES FOR THIS
TIME OF YEAR. HUMIDITIES LOOK TO DROP INTO THE TEENS AND 20S FOR
MUCH OF THE AREA...WHILE  WINDS WILL CONTINUE TO BE GUSTY ALONG AND
WEST OF THE LARAMIE RANGE. WILL CONTINUE TO MONITOR TUESDAY FOR
ELEVATED FIRE WEATHER CONCERNS.

.LONG TERM...(WEDNESDAY THROUGH SATURDAY)
ISSUED AT 345 PM MDT SUN AUG 31 2014

WEDNESDAY WILL BE THE WARMEST DAY OF THE EXTENDED PERIOD WITH
SOUTHWESTERLY FLOW ALOFT AND A LEE TROUGH AT THE SFC.  700MB TEMPS
WILL RISE TO 16C WITH AROUND 30C AT 850MB.  HIGHS OVER THE PLAINS
WILL BE IN THE UPPER 80S TO LOW 90S...WHICH IS 5-10 DEGREES ABOVE
NORMAL FOR EARLY SEPTEMBER.  MAY HAVE TO DEAL WITH SOME FIRE WEATHER
CONCERNS OVER SOUTHEAST WY AS MIN RH VALUES DROP TO AROUND 15
PERCENT AND WINDS WILL BE BREEZY...ESPECIALLY TO THE WEST OF THE
LARAMIE RANGE.  UPPER LEVEL WAVE PUSHES FROM THE NORTHERN ROCKIES ON
WED TOWARD NORTH DAKOTA ON THURS.  THIS WILL PUSH A COLD FRONT
THROUGH THE CWA ON THURS MORNING WITH 10-15 DEGREES OF COOLING.  IT
IS GENERALLY A DRY FRONTAL PASSAGE...AT LEAST INITIALLY.  BY THURS
NIGHT INTO FRI THIS COULD CHANGE AS ISENTROPIC LIFT COMBINES WITH
IMPROVING JET DYNAMICS SUCH THAT SCATTERED SHOWERS DEVELOP OVER
PORTIONS OF THE CWA.  THE ECMWF HAS WIDESPREAD SHOWERS ON THURS
NIGHT WHEREAS THE GFS HAS THIS AREA FURTHER SOUTH OVER NORTHERN
COLORADO.  LLVL SOUTHEASTERLY UPSLOPE WILL CONTINUE THROUGH SATURDAY
WITH WEAK SHORTWAVES MOVING ACROSS THE REGION FROM THE SOUTHWEST.
SEEMS LIKE A FAVORABLE PATTERN FOR AT LEAST ISOLATED TO SCATTERED
SHOWERS AT TIMES ALONG WITH INCREASED CLOUD COVER AND GENERALLY HAVE
SLIGHT CHANCE POPS ON FRI AND SAT.  INSTABILITY IS QUITE LIMITED
THROUGH FRI...THEN IMPROVES SOME BY SAT (CAPE VALUES INCREASE TO
500-750 J/KG).

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY AFTERNOON)
ISSUED AT 505 PM MDT SUN AUG 31 2014

MAINLY VFR FOR TONIGHT INO MONDAY AS WESTERLY DOWNSLOPING WINDS
WILL BE IN PLACE. RADAR TRENDS ARE SHOWING CONVECTION ACROSS
NIOBRARA COUNTY INTO THE NORTHERN PANHANDLE. THIS SHOULD COME TO
AN END BY SUNSET. WESTERLY WINS RETURN MONDAY AFTERNOON AND WILL
GUST INTO THE 20KT RANGE ONCE AGAIN.

&&

.FIRE WEATHER...
ISSUED AT 345 PM MDT SUN AUG 31 2014

SCATTERED SHOWERS AND T-STORMS WILL CONTINUE OVER THE DISTRICT
THROUGH EARLY THIS EVENING BEFORE COMING TO AN END TONIGHT. LIGHT
TO MODERATE RAIN...GUSTY DOWNDRAFT WINDS...AND OCCASIONAL
LIGHTNING WILL ACCOMPANY THE STORMS. A WEAK DISTURBANCE MOVING
OVERHEAD ON MONDAY WILL BRING A CHANCE FOR MORE ISOLATED SHOWERS
AND STORMS MAINLY OVER NORTHERN AND EASTERN PORTIONS OF THE
DISTRICT IN THE AFTERNOON. LIGHT RAINFALL AND GUSTY WINDS WILL
REMAIN A POSSIBILITY WITH THIS ACTIVITY. A MUCH DRIER AIRMASS WILL
MOVE OVERHEAD TUESDAY AND WILL REMAIN IN PLACE THROUGH WEDNESDAY.
TEMPERATURES WILL WARM BACK TO ABOVE NORMAL READINGS BY
WEDNESDAY AS WELL...WHILE WEST TO SOUTHWEST WINDS WILL REMAIN
GUSTY IN AREAS ALONG AND WEST OF THE LARAMIE RANGE.

&&

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

$$

SHORT TERM...RJM
LONG TERM...FINCH
AVIATION...CLAYCOMB
FIRE WEATHER...RJM






000
FXUS65 KCYS 312145
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
345 PM MDT SUN AUG 31 2014

.SHORT TERM...(THIS EVENING THROUGH TUESDAY NIGHT)
ISSUED AT 345 PM MDT SUN AUG 31 2014

WATER VAPOR IMAGERY THIS AFTERNOON SHOWS THE UPPER LEVEL SHORTWAVE
MOVING OVER THE FORECAST AREA WITHIN THE LEFT EXIT REGION OF A 100
KT JET. AS OF 3 PM...THE SFC COLD FRONT LOOKS TO EXTEND ROUGHLY
FROM SOUTHEAST NIOBRARA COUNTY...THROUGH CONVERSE COUNTY...AND
WESTWARD THROUGH NATRONA COUNTY AND IS STEADILY MOVING SOUTH.
SCATTERED TO NUMEROUS SHOWERS AND T-STORMS HAVE DEVELOPED ACROSS
NORTHERN PORTIONS OF THE FORECAST AREA THIS AFTERNOON WITHIN THE
STRONGEST UPPER LEVEL AND SFC FORCING...WITH A FEW UPDRAFTS
SPIKING ABOVE 20KFT WITH THE HELP OF 500 TO 1000 J/KG OF MLCAPE.
MAINTAINED MENTION IN THE FORECAST FOR GUSTY WINDS AND SMALL HAIL
WITH THIS ACTIVITY THROUGH THE LATE AFTERNOON. 30 TO 40 KTS OF
BULK SHEAR IS ANALYZED OVER THE NEB PANHANDLE COINCIDENT WITH THE
HIGHER VALUES OF INSTABILITY...SO THE POSSIBILITY DOES EXIST FOR A
FEW STORMS TO BECOME STRONGER AS THEY TREK EAST TOWARD THE
SANDHILLS. WEAKER CONVECTION ALSO DEVELOPED OVER THE MOUNTAINS OF
SOUTHEAST WYOMING AND COLORADO EARLIER...WITH SOME OF THIS ACTIVITY
MOVING OFF THE HIGH TERRAIN AND ALONG THE CHEYENNE RIDGE AS WELL.
WATER VAPOR IMAGERY AND SPC MESOANALYSIS DATA INDICATE A BROADER
AREA OF SUBSIDENCE WAS OVER THIS AREA DURING THIS TIME...AND
LIKELY STUNTED THE GROWTH OF THE CONVECTION WHILE FORCING SOME
STRONGER WIND GUSTS AROUND 50 MPH TO THE SFC. A FEW SHOWERS
CONTINUE TO DEVELOP OVER MOUNTAINS AT THIS HOUR...BUT EXPECT A
SIMILAR TREND FOR WEAK BUT GUSTY SHOWERS AS DRIER AIR AND SOME
UPPER LEVEL SUBSIDENCE REMAIN IN PLACE HERE.

THE FRONT WILL CONTINUE TO MOVE SOUTH ACROSS EASTERN COUNTIES
THROUGH THIS EVENING WHILE DRIER AIR MOVES OVERHEAD AND SUBSIDENCE
BECOMES MORE WIDESPREAD. THUS EXPECT ACTIVITY TO COME TO AN END
QUICKLY AROUND SUNSET. ANOTHER SHORTWAVE WILL MOVE OVERHEAD TOMORROW
AFTERNOON...ALTHOUGH A MUCH DRIER AIRMASS WILL BE IN PLACE WHICH
WILL MINIMIZE COVERAGE OF SHOWERS AND STORMS. THE FOCUS FOR ACTIVITY
WILL BE ACROSS THE NORTHERN ZONES ONCE AGAIN ON THE LEADING EDGE OF
ANOTHER BACKDOOR COLD FRONT MOVING WITH THE UPPER WAVE. A FEW STORMS
COULD BECOME STRONG IN THIS AREA AS 30 KTS OF SHEAR IS PROGGED BY
THE NAM HERE. THE ONE LIMITING FACTOR WILL BE AVAILABLE INSTABILITY AS
MODELS DEVELOP ONLY ABOUT 500 J/KG OF CAPE BY THE AFTERNOON.
CANNOT RULE OUT A FEW WEAKER SHOWERS/STORMS DEVELOPING AND MOVING
OFF THE LARAMIE RANGE AS WELL IN THE LATE AFTERNOON BUT THESE WILL
BE WEAK AND VERY ISOLATED.

DRY ZONAL FLOW WILL THEN TAKE AHOLD OF THE FORECAST AREA FOR
TUESDAY...WITH TEMPS WARMING BACK TO MORE NORMAL VALUES FOR THIS
TIME OF YEAR. HUMIDITIES LOOK TO DROP INTO THE TEENS AND 20S FOR
MUCH OF THE AREA...WHILE  WINDS WILL CONTINUE TO BE GUSTY ALONG AND
WEST OF THE LARAMIE RANGE. WILL CONTINUE TO MONITOR TUESDAY FOR
ELEVATED FIRE WEATHER CONCERNS.

.LONG TERM...(WEDNESDAY THROUGH SATURDAY)
ISSUED AT 345 PM MDT SUN AUG 31 2014

WEDNESDAY WILL BE THE WARMEST DAY OF THE EXTENDED PERIOD WITH
SOUTHWESTERLY FLOW ALOFT AND A LEE TROUGH AT THE SFC.  700MB TEMPS
WILL RISE TO 16C WITH AROUND 30C AT 850MB.  HIGHS OVER THE PLAINS
WILL BE IN THE UPPER 80S TO LOW 90S...WHICH IS 5-10 DEGREES ABOVE
NORMAL FOR EARLY SEPTEMBER.  MAY HAVE TO DEAL WITH SOME FIRE WEATHER
CONCERNS OVER SOUTHEAST WY AS MIN RH VALUES DROP TO AROUND 15
PERCENT AND WINDS WILL BE BREEZY...ESPECIALLY TO THE WEST OF THE
LARAMIE RANGE.  UPPER LEVEL WAVE PUSHES FROM THE NORTHERN ROCKIES ON
WED TOWARD NORTH DAKOTA ON THURS.  THIS WILL PUSH A COLD FRONT
THROUGH THE CWA ON THURS MORNING WITH 10-15 DEGREES OF COOLING.  IT
IS GENERALLY A DRY FRONTAL PASSAGE...AT LEAST INITIALLY.  BY THURS
NIGHT INTO FRI THIS COULD CHANGE AS ISENTROPIC LIFT COMBINES WITH
IMPROVING JET DYNAMICS SUCH THAT SCATTERED SHOWERS DEVELOP OVER
PORTIONS OF THE CWA.  THE ECMWF HAS WIDESPREAD SHOWERS ON THURS
NIGHT WHEREAS THE GFS HAS THIS AREA FURTHER SOUTH OVER NORTHERN
COLORADO.  LLVL SOUTHEASTERLY UPSLOPE WILL CONTINUE THROUGH SATURDAY
WITH WEAK SHORTWAVES MOVING ACROSS THE REGION FROM THE SOUTHWEST.
SEEMS LIKE A FAVORABLE PATTERN FOR AT LEAST ISOLATED TO SCATTERED
SHOWERS AT TIMES ALONG WITH INCREASED CLOUD COVER AND GENERALLY HAVE
SLIGHT CHANCE POPS ON FRI AND SAT.  INSTABILITY IS QUITE LIMITED
THROUGH FRI...THEN IMPROVES SOME BY SAT (CAPE VALUES INCREASE TO
500-750 J/KG).

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY MORNING)
ISSUED AT 1146 AM MDT SUN AUG 31 2014

SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS WILL BE POSSIBLE
THROUGH THE AFTERNOON. MUCH OF THE ACTIVITY WILL SHIFT EASTWARD
OUT OF SOUTHEAST WY BY LATE AFTERNOON. MODERATE RAIN WILL
ACCOMPANY SOME OF THE STRONGER SHOWERS...WITH BRIEF MVFR VIS
POSSIBLE. WEST TO NORTHWEST WINDS WILL BE BREEZY THROUGH 00Z OVER
MUCH OF SOUTHEAST WY WITH GUSTS TO 30 KTS.

&&

.FIRE WEATHER...
ISSUED AT 345 PM MDT SUN AUG 31 2014

SCATTERED SHOWERS AND T-STORMS WILL CONTINUE OVER THE DISTRICT
THROUGH EARLY THIS EVENING BEFORE COMING TO AN END TONIGHT. LIGHT
TO MODERATE RAIN...GUSTY DOWNDRAFT WINDS...AND OCCASIONAL
LIGHTNING WILL ACCOMPANY THE STORMS. A WEAK DISTURBANCE MOVING
OVERHEAD ON MONDAY WILL BRING A CHANCE FOR MORE ISOLATED SHOWERS
AND STORMS MAINLY OVER NORTHERN AND EASTERN PORTIONS OF THE
DISTRICT IN THE AFTERNOON. LIGHT RAINFALL AND GUSTY WINDS WILL
REMAIN A POSSIBILITY WITH THIS ACTIVITY. A MUCH DRIER AIRMASS WILL
MOVE OVERHEAD TUESDAY AND WILL REMAIN IN PLACE THROUGH WEDNESDAY.
TEMPERATURES WILL WARM BACK TO ABOVE NORMAL READINGS BY
WEDNESDAY AS WELL...WHILE WEST TO SOUTHWEST WINDS WILL REMAIN
GUSTY IN AREAS ALONG AND WEST OF THE LARAMIE RANGE.

&&

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

$$

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







000
FXUS65 KCYS 312145
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
345 PM MDT SUN AUG 31 2014

.SHORT TERM...(THIS EVENING THROUGH TUESDAY NIGHT)
ISSUED AT 345 PM MDT SUN AUG 31 2014

WATER VAPOR IMAGERY THIS AFTERNOON SHOWS THE UPPER LEVEL SHORTWAVE
MOVING OVER THE FORECAST AREA WITHIN THE LEFT EXIT REGION OF A 100
KT JET. AS OF 3 PM...THE SFC COLD FRONT LOOKS TO EXTEND ROUGHLY
FROM SOUTHEAST NIOBRARA COUNTY...THROUGH CONVERSE COUNTY...AND
WESTWARD THROUGH NATRONA COUNTY AND IS STEADILY MOVING SOUTH.
SCATTERED TO NUMEROUS SHOWERS AND T-STORMS HAVE DEVELOPED ACROSS
NORTHERN PORTIONS OF THE FORECAST AREA THIS AFTERNOON WITHIN THE
STRONGEST UPPER LEVEL AND SFC FORCING...WITH A FEW UPDRAFTS
SPIKING ABOVE 20KFT WITH THE HELP OF 500 TO 1000 J/KG OF MLCAPE.
MAINTAINED MENTION IN THE FORECAST FOR GUSTY WINDS AND SMALL HAIL
WITH THIS ACTIVITY THROUGH THE LATE AFTERNOON. 30 TO 40 KTS OF
BULK SHEAR IS ANALYZED OVER THE NEB PANHANDLE COINCIDENT WITH THE
HIGHER VALUES OF INSTABILITY...SO THE POSSIBILITY DOES EXIST FOR A
FEW STORMS TO BECOME STRONGER AS THEY TREK EAST TOWARD THE
SANDHILLS. WEAKER CONVECTION ALSO DEVELOPED OVER THE MOUNTAINS OF
SOUTHEAST WYOMING AND COLORADO EARLIER...WITH SOME OF THIS ACTIVITY
MOVING OFF THE HIGH TERRAIN AND ALONG THE CHEYENNE RIDGE AS WELL.
WATER VAPOR IMAGERY AND SPC MESOANALYSIS DATA INDICATE A BROADER
AREA OF SUBSIDENCE WAS OVER THIS AREA DURING THIS TIME...AND
LIKELY STUNTED THE GROWTH OF THE CONVECTION WHILE FORCING SOME
STRONGER WIND GUSTS AROUND 50 MPH TO THE SFC. A FEW SHOWERS
CONTINUE TO DEVELOP OVER MOUNTAINS AT THIS HOUR...BUT EXPECT A
SIMILAR TREND FOR WEAK BUT GUSTY SHOWERS AS DRIER AIR AND SOME
UPPER LEVEL SUBSIDENCE REMAIN IN PLACE HERE.

THE FRONT WILL CONTINUE TO MOVE SOUTH ACROSS EASTERN COUNTIES
THROUGH THIS EVENING WHILE DRIER AIR MOVES OVERHEAD AND SUBSIDENCE
BECOMES MORE WIDESPREAD. THUS EXPECT ACTIVITY TO COME TO AN END
QUICKLY AROUND SUNSET. ANOTHER SHORTWAVE WILL MOVE OVERHEAD TOMORROW
AFTERNOON...ALTHOUGH A MUCH DRIER AIRMASS WILL BE IN PLACE WHICH
WILL MINIMIZE COVERAGE OF SHOWERS AND STORMS. THE FOCUS FOR ACTIVITY
WILL BE ACROSS THE NORTHERN ZONES ONCE AGAIN ON THE LEADING EDGE OF
ANOTHER BACKDOOR COLD FRONT MOVING WITH THE UPPER WAVE. A FEW STORMS
COULD BECOME STRONG IN THIS AREA AS 30 KTS OF SHEAR IS PROGGED BY
THE NAM HERE. THE ONE LIMITING FACTOR WILL BE AVAILABLE INSTABILITY AS
MODELS DEVELOP ONLY ABOUT 500 J/KG OF CAPE BY THE AFTERNOON.
CANNOT RULE OUT A FEW WEAKER SHOWERS/STORMS DEVELOPING AND MOVING
OFF THE LARAMIE RANGE AS WELL IN THE LATE AFTERNOON BUT THESE WILL
BE WEAK AND VERY ISOLATED.

DRY ZONAL FLOW WILL THEN TAKE AHOLD OF THE FORECAST AREA FOR
TUESDAY...WITH TEMPS WARMING BACK TO MORE NORMAL VALUES FOR THIS
TIME OF YEAR. HUMIDITIES LOOK TO DROP INTO THE TEENS AND 20S FOR
MUCH OF THE AREA...WHILE  WINDS WILL CONTINUE TO BE GUSTY ALONG AND
WEST OF THE LARAMIE RANGE. WILL CONTINUE TO MONITOR TUESDAY FOR
ELEVATED FIRE WEATHER CONCERNS.

.LONG TERM...(WEDNESDAY THROUGH SATURDAY)
ISSUED AT 345 PM MDT SUN AUG 31 2014

WEDNESDAY WILL BE THE WARMEST DAY OF THE EXTENDED PERIOD WITH
SOUTHWESTERLY FLOW ALOFT AND A LEE TROUGH AT THE SFC.  700MB TEMPS
WILL RISE TO 16C WITH AROUND 30C AT 850MB.  HIGHS OVER THE PLAINS
WILL BE IN THE UPPER 80S TO LOW 90S...WHICH IS 5-10 DEGREES ABOVE
NORMAL FOR EARLY SEPTEMBER.  MAY HAVE TO DEAL WITH SOME FIRE WEATHER
CONCERNS OVER SOUTHEAST WY AS MIN RH VALUES DROP TO AROUND 15
PERCENT AND WINDS WILL BE BREEZY...ESPECIALLY TO THE WEST OF THE
LARAMIE RANGE.  UPPER LEVEL WAVE PUSHES FROM THE NORTHERN ROCKIES ON
WED TOWARD NORTH DAKOTA ON THURS.  THIS WILL PUSH A COLD FRONT
THROUGH THE CWA ON THURS MORNING WITH 10-15 DEGREES OF COOLING.  IT
IS GENERALLY A DRY FRONTAL PASSAGE...AT LEAST INITIALLY.  BY THURS
NIGHT INTO FRI THIS COULD CHANGE AS ISENTROPIC LIFT COMBINES WITH
IMPROVING JET DYNAMICS SUCH THAT SCATTERED SHOWERS DEVELOP OVER
PORTIONS OF THE CWA.  THE ECMWF HAS WIDESPREAD SHOWERS ON THURS
NIGHT WHEREAS THE GFS HAS THIS AREA FURTHER SOUTH OVER NORTHERN
COLORADO.  LLVL SOUTHEASTERLY UPSLOPE WILL CONTINUE THROUGH SATURDAY
WITH WEAK SHORTWAVES MOVING ACROSS THE REGION FROM THE SOUTHWEST.
SEEMS LIKE A FAVORABLE PATTERN FOR AT LEAST ISOLATED TO SCATTERED
SHOWERS AT TIMES ALONG WITH INCREASED CLOUD COVER AND GENERALLY HAVE
SLIGHT CHANCE POPS ON FRI AND SAT.  INSTABILITY IS QUITE LIMITED
THROUGH FRI...THEN IMPROVES SOME BY SAT (CAPE VALUES INCREASE TO
500-750 J/KG).

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY MORNING)
ISSUED AT 1146 AM MDT SUN AUG 31 2014

SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS WILL BE POSSIBLE
THROUGH THE AFTERNOON. MUCH OF THE ACTIVITY WILL SHIFT EASTWARD
OUT OF SOUTHEAST WY BY LATE AFTERNOON. MODERATE RAIN WILL
ACCOMPANY SOME OF THE STRONGER SHOWERS...WITH BRIEF MVFR VIS
POSSIBLE. WEST TO NORTHWEST WINDS WILL BE BREEZY THROUGH 00Z OVER
MUCH OF SOUTHEAST WY WITH GUSTS TO 30 KTS.

&&

.FIRE WEATHER...
ISSUED AT 345 PM MDT SUN AUG 31 2014

SCATTERED SHOWERS AND T-STORMS WILL CONTINUE OVER THE DISTRICT
THROUGH EARLY THIS EVENING BEFORE COMING TO AN END TONIGHT. LIGHT
TO MODERATE RAIN...GUSTY DOWNDRAFT WINDS...AND OCCASIONAL
LIGHTNING WILL ACCOMPANY THE STORMS. A WEAK DISTURBANCE MOVING
OVERHEAD ON MONDAY WILL BRING A CHANCE FOR MORE ISOLATED SHOWERS
AND STORMS MAINLY OVER NORTHERN AND EASTERN PORTIONS OF THE
DISTRICT IN THE AFTERNOON. LIGHT RAINFALL AND GUSTY WINDS WILL
REMAIN A POSSIBILITY WITH THIS ACTIVITY. A MUCH DRIER AIRMASS WILL
MOVE OVERHEAD TUESDAY AND WILL REMAIN IN PLACE THROUGH WEDNESDAY.
TEMPERATURES WILL WARM BACK TO ABOVE NORMAL READINGS BY
WEDNESDAY AS WELL...WHILE WEST TO SOUTHWEST WINDS WILL REMAIN
GUSTY IN AREAS ALONG AND WEST OF THE LARAMIE RANGE.

&&

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

$$

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






000
FXUS63 KUNR 312100
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
300 PM MDT SUN AUG 31 2014

.SHORT TERM...THIS EVENING THROUGH MONDAY NIGHT
ISSUED AT 300 PM MDT SUN AUG 31 2014

CURRENT SURFACE ANALYSIS SHOWS LOW PRESSURE OVER NORTHWEST
MN...WITH COLD FRONT WELL EAST OF OUR FORECAST AREA. UPPER LEVEL
ANALYSIS SHOWS BROAD TROF OVER THE WESTERN CONUS...WITH A SERIES
OF SHORTWAVES WITHIN THE TROF MOVING EAST THROUGH THE ROCKIES AND
PLAINS. LAST NIGHTS WAVE HAS MOVED WELL EAST OF THE AREA...WHILE
THE NEXT ONE IS MOVING QUICKLY ACROSS EASTERN WY INTO WESTERN SD
AND WESTERN NEB. KUDX RADAR SHOWS NUMEROUS SHOWERS AND
THUNDERSTORMS OVER MUCH OF NORTHEAST WY AND WESTERN SD...WITH THE
HEAVIEST ACTIVITY GENERALLY OVER AND AROUND THE BLACK HILLS. TEMPS
ARE IN THE 60S TO MID 70S WITH NORTHERLY WINDS IN MOST AREAS.

THE UNSETTLED WEATHER PATTERN WILL CONTINUE THROUGH LABOR DAY AS
THIS LATEST DISTURBANCE EXITS THIS EVENING AND THE NEXT ONE PUSHES
THROUGH ON MONDAY. A BREAK IN THE PATTERN CAN BE EXPECTED FOR
TUESDAY AND WEDNESDAY.

FOR LATE TODAY AND TONIGHT...SHOWERS AND THUNDERSTORMS WILL CONTINUE
TO TRACK EAST ACROSS THE AREA...ENDING ACROSS NORTHEAST WY BY EARLY
EVENING AND FROM WEST TO EAST ACROSS WESTERN SD DURING THE EVENING.
THE BEST CHANCES FOR PCPN WILL BE EAST OF THE BLACK HILLS DURING THE
EVENING. SKIES WILL CLEAR OUT BEHIND THE WAVE FOR A WHILE...BUT
CLOUDS WILL INCREASE AGAIN FROM THE WEST LATE TONIGHT INTO MONDAY
MORNING AS THE NEXT DISTURBANCE APPROACHES. WILL KEEP A SLIGHT
CHANCE FOR SHOWERS LATE TONIGHT OVER NORTHEAST WY AND FAR NORTHWEST
SD. A COOL NIGHT IS ON TAP WITH LOWS IN THE MID 40S TO MID
50S...COOLEST OVER THE BLACK HILLS AND USUAL VALLEY LOCATIONS.

ANOTHER COOL DAY CAN BE EXPECTED MONDAY...WITH CHANCES FOR SHOWERS
AND STORMS INCREASING THROUGH THE MORNING AND INTO THE AFTERNOON
FROM WEST TO EAST. SHOWERS WILL LIKELY NOT BE AS NUMEROUS AS
TODAY...BUT SHOULD BE AT LEAST SCATTERED IN COVERAGE ACROSS MOST
AREAS. HIGHS WILL BE IN THE 70S ACROSS MOST OF THE PLAINS...WITH 60S
OVER THE BLACK HILLS. THREAT FOR SEVERE WEATHER WILL AGAIN BE
MINIMAL AT BEST WITH RELATIVELY WEAK INSTABILITY IN PLACE FOR STRONG
STORMS. SHOWERS WILL EXIT THE AREA FROM WEST TO EAST LATE MONDAY AND
MONDAY EVENING.

&&

.LONG TERM...TUESDAY THROUGH SUNDAY
ISSUED AT 300 PM MDT SUN AUG 31 2014

AN UPPER TROUGH WILL DEEPEN OVER THE PACIFIC NORTHWEST
TUESDAY/WEDNESDAY BRINGING A FLAT UPPER RIDGE/THERMAL RIDGE OVER THE
AREA. RESULT WILL BE DRIER WEATHER AND WARMER TEMPERATURES. A
SPIRITED SHORTWAVE WILL PUSH THROUGH THE CWA WEDNESDAY
NIGHT/THURSDAY BRINGING A SHARP COLD FRONT AND LOWER TEMPERATURES
FOR THURSDAY/FRIDAY. SMALL POPS LOOK REASONABLE BEHIND FRONT THROUGH
NEXT WEEKEND GIVEN WEST/NORTHWEST FLOW ALOFT.

&&

.AVIATION...FOR THE 18Z TAFS THROUGH 18Z MONDAY
ISSUED AT 300 PM MDT SUN AUG 31 2014

SOME SHOWERS AND THUNDERSTORMS WILL BE FOUND ACROSS THE
AREA THROUGH MONDAY. THE BEST COVERAGE WILL LAST FROM NOW INTO THE
EARLY EVENING HOURS. LOCAL MVFR CIGS/IFR VSBYS ARE POSSIBLE WITH THE
STRONGER SHOWERS/STORMS.

&&

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

$$

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







000
FXUS63 KUNR 312100
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
300 PM MDT SUN AUG 31 2014

.SHORT TERM...THIS EVENING THROUGH MONDAY NIGHT
ISSUED AT 300 PM MDT SUN AUG 31 2014

CURRENT SURFACE ANALYSIS SHOWS LOW PRESSURE OVER NORTHWEST
MN...WITH COLD FRONT WELL EAST OF OUR FORECAST AREA. UPPER LEVEL
ANALYSIS SHOWS BROAD TROF OVER THE WESTERN CONUS...WITH A SERIES
OF SHORTWAVES WITHIN THE TROF MOVING EAST THROUGH THE ROCKIES AND
PLAINS. LAST NIGHTS WAVE HAS MOVED WELL EAST OF THE AREA...WHILE
THE NEXT ONE IS MOVING QUICKLY ACROSS EASTERN WY INTO WESTERN SD
AND WESTERN NEB. KUDX RADAR SHOWS NUMEROUS SHOWERS AND
THUNDERSTORMS OVER MUCH OF NORTHEAST WY AND WESTERN SD...WITH THE
HEAVIEST ACTIVITY GENERALLY OVER AND AROUND THE BLACK HILLS. TEMPS
ARE IN THE 60S TO MID 70S WITH NORTHERLY WINDS IN MOST AREAS.

THE UNSETTLED WEATHER PATTERN WILL CONTINUE THROUGH LABOR DAY AS
THIS LATEST DISTURBANCE EXITS THIS EVENING AND THE NEXT ONE PUSHES
THROUGH ON MONDAY. A BREAK IN THE PATTERN CAN BE EXPECTED FOR
TUESDAY AND WEDNESDAY.

FOR LATE TODAY AND TONIGHT...SHOWERS AND THUNDERSTORMS WILL CONTINUE
TO TRACK EAST ACROSS THE AREA...ENDING ACROSS NORTHEAST WY BY EARLY
EVENING AND FROM WEST TO EAST ACROSS WESTERN SD DURING THE EVENING.
THE BEST CHANCES FOR PCPN WILL BE EAST OF THE BLACK HILLS DURING THE
EVENING. SKIES WILL CLEAR OUT BEHIND THE WAVE FOR A WHILE...BUT
CLOUDS WILL INCREASE AGAIN FROM THE WEST LATE TONIGHT INTO MONDAY
MORNING AS THE NEXT DISTURBANCE APPROACHES. WILL KEEP A SLIGHT
CHANCE FOR SHOWERS LATE TONIGHT OVER NORTHEAST WY AND FAR NORTHWEST
SD. A COOL NIGHT IS ON TAP WITH LOWS IN THE MID 40S TO MID
50S...COOLEST OVER THE BLACK HILLS AND USUAL VALLEY LOCATIONS.

ANOTHER COOL DAY CAN BE EXPECTED MONDAY...WITH CHANCES FOR SHOWERS
AND STORMS INCREASING THROUGH THE MORNING AND INTO THE AFTERNOON
FROM WEST TO EAST. SHOWERS WILL LIKELY NOT BE AS NUMEROUS AS
TODAY...BUT SHOULD BE AT LEAST SCATTERED IN COVERAGE ACROSS MOST
AREAS. HIGHS WILL BE IN THE 70S ACROSS MOST OF THE PLAINS...WITH 60S
OVER THE BLACK HILLS. THREAT FOR SEVERE WEATHER WILL AGAIN BE
MINIMAL AT BEST WITH RELATIVELY WEAK INSTABILITY IN PLACE FOR STRONG
STORMS. SHOWERS WILL EXIT THE AREA FROM WEST TO EAST LATE MONDAY AND
MONDAY EVENING.

&&

.LONG TERM...TUESDAY THROUGH SUNDAY
ISSUED AT 300 PM MDT SUN AUG 31 2014

AN UPPER TROUGH WILL DEEPEN OVER THE PACIFIC NORTHWEST
TUESDAY/WEDNESDAY BRINGING A FLAT UPPER RIDGE/THERMAL RIDGE OVER THE
AREA. RESULT WILL BE DRIER WEATHER AND WARMER TEMPERATURES. A
SPIRITED SHORTWAVE WILL PUSH THROUGH THE CWA WEDNESDAY
NIGHT/THURSDAY BRINGING A SHARP COLD FRONT AND LOWER TEMPERATURES
FOR THURSDAY/FRIDAY. SMALL POPS LOOK REASONABLE BEHIND FRONT THROUGH
NEXT WEEKEND GIVEN WEST/NORTHWEST FLOW ALOFT.

&&

.AVIATION...FOR THE 18Z TAFS THROUGH 18Z MONDAY
ISSUED AT 300 PM MDT SUN AUG 31 2014

SOME SHOWERS AND THUNDERSTORMS WILL BE FOUND ACROSS THE
AREA THROUGH MONDAY. THE BEST COVERAGE WILL LAST FROM NOW INTO THE
EARLY EVENING HOURS. LOCAL MVFR CIGS/IFR VSBYS ARE POSSIBLE WITH THE
STRONGER SHOWERS/STORMS.

&&

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

$$

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






000
FXUS65 KRIW 312100
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
300 PM MDT SUN AUG 31 2014

.SHORT TERM...TONIGHT THROUGH MONDAY

EXPANDING UPR LVL TROF ACROSS THE CONUS W OF THE MISSISSIPPI...W/
BASE OF TROF SWINGING EWD ACROSS WY TODAY. ANOTHER EMBEDDED SW TROF
MOVING THRU THE CNTRL FA INTO THE ERN PORTIONS OF THE STATE THIS
AFTERNOON. ANOTHER EMBEDDED SW LIES IN WAIT UPSTREAM JUST OFF THE
COAST OF OR/WA...AND WILL RACE INTO WRN/NWRN WY BY MONDAY MORNING.
AT THE SFC...GENERAL HIGH P TO THE W OF THE STATE...LOW P E WITH
FRONT/BOUNDARY BISECTING THE STATE FROM E TO SW CUTTING FROM NRN
NATRONA COUNTY...TO NRN SWEETWATER COUNTY AND W INTO SRN LINCOLN
COUNTY.

TODAY... OVERALL...MUCH COOLER CONDITIONS FROM FRONTAL
PASSAGE AND/OR SIGNIFICANT UPR LVL TEMP DROP AND CLOUD COVER.
CONTINUED  RELATIVELY STRONG GUSTY W TO WSW WINDS ACROSS THE SRN FA
SOUTH OF THE FRONT/BOUNDARY MENTIONED ABOVE...WITH GUSTY N TO NW
WINDS BEHIND THE FRONT. ANOTHER WEAKER FRONT LOOK TO BE LAYING
ACROSS MT AND WILL ENTER THE NRN AND ERN PORTION OF THE FA ON
MONDAY. ISOLATED TO SCATTERED SHOWERS AND ISOLATED THUNDER  ARE
MAKING THEIR WAY ACROSS PORTIONS OF CENTRAL AND EASTERN WY THIS
AFTERNOON...AND WILL CONTINUE AN EWD TRACK...DECREASING FROM W TO E
INTO THE EVENING. STRONGER STORMS WITH SMALL HAIL AND GUSTY WINDS
WILL BE MOST PROBABLE ERN FREMONT AND ACROSS NATRONA COUNTIES
NEAR/ALONG FRONT/BOUNDARY. CAPE AND SHEAR IN THIS AREA ARE 500-700
J/KG AND 25-30 KTS RESPECTIVELY...JUST ENOUGH TO WEAKLY ORGANIZE A
STORM OR TWO.

TONIGHT AND MONDAY...MAIN TROF PASSES E AND INTO THE GREAT PLAINS...UPR
LVL NW FLOW CONTINUES...AND THE OR/WA DISTURBANCE CONTINUES TO HEAD
THIS WAY THRU THE BACKSIDE OF THE LW TROF...ARRIVING NEAR THE WRN
BORDER BETWEEN 06 AND 09Z...THEN TRANSLATING ACROSS THE FA QUICKLY
BY EARLY AFTERNOON.  THIS WILL KEEP A NEARLY CONTINUAL CHC FOR SHRA
GOING ACROSS THE NW FA THROUGH AT LEAST MID TO LATE MORNING
MONDAY...AND ACROSS THE NRN/NERN FA INTO THE AFTERNOON. WHILE THIS
UPR LVL ENERGY WILL EXTEND WELL SOUTH AND OVR MOST OF THE
CWA...RAPID DRYING OF THE ATMOSPHERE WILL OCCUR BEHIND THE PASSAGE
OF THE MAIN TROF AXIS TONIGHT AND THROUGH MONDAY MORNING FROM W TO
E...AND THERE WILL NOT BE MUCH IN THE WAY OF MOISTURE TO ACT ON. A
FEW STRONGER STORMS MAY OCCUR OVR JOHNSON COUNTY BY EARLY AFTERNOON
WHERE SOME USEFUL MOISTURE WILL STILL BE LEFTOVER...CAPE WILL BE
MARGINAL AND SHEAR WILL BE MAXIMIZED ALONG AND NORTH OF A
CLIPPER-LIKE BOUNDARY/FRONT. SNOWFALL WILL BE POSSIBLE AGAIN ACROSS
THE NORTHERN MOUNTAINS...WITH GENERAL 1 INCH ACCUMULATIONS ABOVE
9500 FEET...AND PERHAPS A FEW AREAS ABOVE 10500 FEET RECEIVING UP TO
3 INCHES. NOT EXPECTING MUCH TO STICK TO ANY ASPHALT ROADWAYS
HOWEVER.

.LONG TERM...MONDAY NIGHT THROUGH SUNDAY

MONDAY NIGHT AS THE TROUGH CONTINUE TO MOVE EAST...HIGH PRESSURE
RIDGING WILL OCCUR OVER THE PACIFIC NORTHWEST.  THE MAIN TREND WILL
BE FOR DRYING WITH BREEZY TO WINDY CONDITIONS ACROSS THE SOUTH INTO
CENTRAL AREAS.

TUESDAY AND TUESDAY NIGHT DRY HIGH PRESSURE IS EXPECTED TO DOMINATE
THE WEATHER ACROSS THE AREA WITH INCREASING WEST TO SOUTHWEST WINDS
CENTRAL AND SOUTH WITH GENERAL WARMING. TEMPERATURES SHOULD WARM.

WEDNESDAY AND WEDNESDAY NIGHT  SOME MID LEVEL CLOUDS ARE EXPECTED TO
MOVE UP FROM THE GREAT BASIN IN THE AFTERNOON...OTHERWISE THE DRY
HIGH PRESSURE IS EXPECTED TO CONTINUE TO DOMINATE THE WEATHER WITH
CONTINUED SOUTHWEST WINDS ACROSS THE CENTRAL AND SOUTH WITH THE
WARMING TREND CONTINUING.

THURSDAY AND THURSDAY NIGHT  HIGH PRESSURE WILL SHIFT EAST WITH
INCREASING SOUTHWEST FLOW ALOFT BRINGING SOME PACIFIC MOISTURE ALOFT
OVER THE AREA.  SHOWERS ARE EXPECTED TO DEVELOP WITH ISOLATED
THUNDERSTORMS IN THE AFTERNOON...MOST NUMEROUS OVER THE WESTERN AND
CENTRAL MOUNTAINS.  INCREASED CLOUD COVER  AND A COLD FRONT MOVING
SOUTH FROM MONTANA WILL BRING COOLING.  MODELS STRONGER WITH COLD
FRONT THAN YESTERDAY WITH MORE SIGNIFICANT COOLING.

FRIDAY AND FRIDAY NIGHT  SHOWERS AND ISOLATED THUNDERSTORMS ARE
EXPECTED TO INCREASE OVER THE AREA AS PACIFIC MOISTURE INCREASES IN
SOUTHWEST FLOW ALOFT.  A COLD FRONT WILL CONTINUE TO MOVE SOUTH
INTO SOUTHERN WYOMING.  AGAIN MODELS CONTINUE TO BE STRONGER WITH
THIS COLD FRONT AND ASSOCIATED COOLING BRINGING THE COLD AIR THROUGH
THE SOUTHWEST WHILE YESTERDAY THE FRONT DID NOT MIKE IT THROUGH
CENTRAL WYOMING.

SATURDAY AND SATURDAY NIGHT SOUTHWEST FLOW ALOFT WILL REMAIN IN
PLACE OVER THE AREA WITH A STREAM OF PACIFIC MOISTURE CONTINUING TO
ADVECT INTO THE AREA SUPPORTING SCATTERED SHOWERS AND SOME ISOLATED
AFTERNOON THUNDERSTORMS.  A FRONT IS EXPECTED TO REMAIN THROUGH
SOUTHERN WYOMING WITH CONTINUED COOLING.

SUNDAY SOME DRYING IS EXPECTED IN THE WEST WITH POSSIBLE WARMING.
OVERALL LOW CONFIDENCE IN FORECAST FOR SUNDAY AS THE SPREAD IN
SOLUTIONS WITH THE EXTENDED MODELS BECOMES MORE SIGNIFICANT.

&&

.AVIATION.../00Z ISSUANCE/

VFR WILL PREVAIL FOR MOST TERMINALS THROUGH THE FORECAST PERIOD. THE
EXCEPTIONS WILL BE KCOD WITH MVFR IN LOW CIGS AND POSSIBLE VIS
RESTRICTIONS THROUGH 18Z MONDAY. LARGE UPPER LEVEL TROUGH CONTINUES
TO EXPAND ACROSS THE COUNTRY WITH AN EMBEDDED DISTURBANCE MOVING
THROUGH THE TROUGH AND ACROSS EASTERN WYOMING THIS AFTERNOON AND
EVENING...EXITING INTO THE HIGH PLAINS BY TONIGHT. ANOTHER
DISTURBANCE WILL FOLLOW BETWEEN 06Z AND 18Z MONDAY...AFFECTING
MAINLY THE NORTHERN FORECAST AREA. ISOLATED TO SCATTERED SHOWERS AND
ISOLATED THUNDERSTORMS WILL CONTINUE ACROSS CENTRAL...EASTERN AND
NORTHERN WYOMING THROUGH 03Z BEFORE BECOMING MORE ISOLATED IN NATURE
FOR MOST LOCATIONS EXCEPT FOR THE NORTHWEST WHICH WILL REMAIN MORE
SCATTERED IN SHOWERS. YELLOWSTONE NATIONAL PARK TO VCNTY COD-BYG AND NORTH
WILL REMAIN MOST ACTIVE AND MOST LIABLE FOR MVFR CONDITIONS TO
PERSIST THROUGH 21Z. SNOW LEVELS WILL HOVER BETWEEN 9-10.5KFT ACROSS
NORTHERN WYOMING...WITH MOUNTAIN OBSCURATIONS AND AREAS OF MVFR TO
OCCASIONAL IFR CONDITIONS. THE OTHER AREA OF MORE ORGANIZED
SHRA/ISOLD TSRA COVERAGE WILL OCCUR FROM VCNTY AND NORTH OF A
KLND-KCPR LINE THROUGH THE THIS EVENING. HOWEVER...CONDITIONS WILL
GENERALLY IMPROVE FROM WEST TO EAST THROUGH THE EVENING. THERE WILL
BE A SLIGHT POSSIBILITY FOR PATCHY FOG DEVELOPING WHERE BETTER RAINS
HAVE FALLEN ESPECIALLY IN WESTERN/NORTHWESTERN MOUNTAIN/VALLEY
LOCATIONS...SUCH AS NEAR AND NORTH OF KJAC AFTER 10Z MONDAY. KCOD
WILL BE THE MOST LIKELY TO SEE SOME VIS REDUCTION DUE TO MIST/FOG AS
MORE PERSISTENT PRECIPITATION WILL CONTINUE IN AND AROUND THE AREA
OVER A LONGER PERIOD.

&&

.FIRE WEATHER...

FIRE DANGER WILL BE RELATIVELY LOW TODAY THROUGH TONIGHT. A LARGE
UPPER LEVEL TROUGH CONTINUES TO EXPAND ACROSS THE COUNTRY TODAY WITH
ANOTHER EMBEDDED DISTURBANCE MOVING THROUGH THE TROUGH AND ACROSS
WYOMING TODAY...THEN INTO THE HIGH PLAINS BY TONIGHT. ANOTHER
DISTURBANCE WILL FOLLOW BETWEEN BETWEEN MIDNIGHT AND EARLY AFTERNOON
MONDAY...AFFECTING MAINLY THE NORTHERN FORECAST ZONES. A SURFACE
FRONT/BOUNDARY LAYS ACROSS NATRONA COUNTY AND WEST INTO SOUTHERN
FREMONT COUNTY THEN NORTHERN SWEETWATER COUNTY. ISOLATED TO
SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS WILL CONTINUE ACROSS
CENTRAL...EASTERN AND NORTHERN WYOMING THROUGH THE AFTERNOON BEFORE
BECOMING MORE ISOLATED IN NATURE FOR MOST LOCATIONS EXCEPT FOR THE
NORTHWEST WHICH WILL CONTINUE MORE SCATTERED. SNOW LEVELS WILL HOVER
BETWEEN 9-10KFT ACROSS THE NORTH. SOUTH OF THE FRONT/BOUNDARY
MENTIONED ABOVE...WEST TO WEST SOUTHWEST WINDS CONTINUE TODAY AT
15-25 MPH WITH GUSTS 35 TO 40 MPH POSSIBLE ALONG WITH MINIMUM RH
VALUES ONLY DROPPING TO 35 PERCENT AT THE LOW END. ISOLATED ERRATIC
OUTFLOW WIND GUSTS NEAR 45KTS WILL BE POSSIBLE WITH A FEW STORMS
THIS AFTERNOON.

&&

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

$$

SHORT TERM...BRAUN
LONG TERM...C.BAKER
AVIATION...BRAUN
FIRE WEATHER...BRAUN





000
FXUS65 KRIW 312100
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
300 PM MDT SUN AUG 31 2014

.SHORT TERM...TONIGHT THROUGH MONDAY

EXPANDING UPR LVL TROF ACROSS THE CONUS W OF THE MISSISSIPPI...W/
BASE OF TROF SWINGING EWD ACROSS WY TODAY. ANOTHER EMBEDDED SW TROF
MOVING THRU THE CNTRL FA INTO THE ERN PORTIONS OF THE STATE THIS
AFTERNOON. ANOTHER EMBEDDED SW LIES IN WAIT UPSTREAM JUST OFF THE
COAST OF OR/WA...AND WILL RACE INTO WRN/NWRN WY BY MONDAY MORNING.
AT THE SFC...GENERAL HIGH P TO THE W OF THE STATE...LOW P E WITH
FRONT/BOUNDARY BISECTING THE STATE FROM E TO SW CUTTING FROM NRN
NATRONA COUNTY...TO NRN SWEETWATER COUNTY AND W INTO SRN LINCOLN
COUNTY.

TODAY... OVERALL...MUCH COOLER CONDITIONS FROM FRONTAL
PASSAGE AND/OR SIGNIFICANT UPR LVL TEMP DROP AND CLOUD COVER.
CONTINUED  RELATIVELY STRONG GUSTY W TO WSW WINDS ACROSS THE SRN FA
SOUTH OF THE FRONT/BOUNDARY MENTIONED ABOVE...WITH GUSTY N TO NW
WINDS BEHIND THE FRONT. ANOTHER WEAKER FRONT LOOK TO BE LAYING
ACROSS MT AND WILL ENTER THE NRN AND ERN PORTION OF THE FA ON
MONDAY. ISOLATED TO SCATTERED SHOWERS AND ISOLATED THUNDER  ARE
MAKING THEIR WAY ACROSS PORTIONS OF CENTRAL AND EASTERN WY THIS
AFTERNOON...AND WILL CONTINUE AN EWD TRACK...DECREASING FROM W TO E
INTO THE EVENING. STRONGER STORMS WITH SMALL HAIL AND GUSTY WINDS
WILL BE MOST PROBABLE ERN FREMONT AND ACROSS NATRONA COUNTIES
NEAR/ALONG FRONT/BOUNDARY. CAPE AND SHEAR IN THIS AREA ARE 500-700
J/KG AND 25-30 KTS RESPECTIVELY...JUST ENOUGH TO WEAKLY ORGANIZE A
STORM OR TWO.

TONIGHT AND MONDAY...MAIN TROF PASSES E AND INTO THE GREAT PLAINS...UPR
LVL NW FLOW CONTINUES...AND THE OR/WA DISTURBANCE CONTINUES TO HEAD
THIS WAY THRU THE BACKSIDE OF THE LW TROF...ARRIVING NEAR THE WRN
BORDER BETWEEN 06 AND 09Z...THEN TRANSLATING ACROSS THE FA QUICKLY
BY EARLY AFTERNOON.  THIS WILL KEEP A NEARLY CONTINUAL CHC FOR SHRA
GOING ACROSS THE NW FA THROUGH AT LEAST MID TO LATE MORNING
MONDAY...AND ACROSS THE NRN/NERN FA INTO THE AFTERNOON. WHILE THIS
UPR LVL ENERGY WILL EXTEND WELL SOUTH AND OVR MOST OF THE
CWA...RAPID DRYING OF THE ATMOSPHERE WILL OCCUR BEHIND THE PASSAGE
OF THE MAIN TROF AXIS TONIGHT AND THROUGH MONDAY MORNING FROM W TO
E...AND THERE WILL NOT BE MUCH IN THE WAY OF MOISTURE TO ACT ON. A
FEW STRONGER STORMS MAY OCCUR OVR JOHNSON COUNTY BY EARLY AFTERNOON
WHERE SOME USEFUL MOISTURE WILL STILL BE LEFTOVER...CAPE WILL BE
MARGINAL AND SHEAR WILL BE MAXIMIZED ALONG AND NORTH OF A
CLIPPER-LIKE BOUNDARY/FRONT. SNOWFALL WILL BE POSSIBLE AGAIN ACROSS
THE NORTHERN MOUNTAINS...WITH GENERAL 1 INCH ACCUMULATIONS ABOVE
9500 FEET...AND PERHAPS A FEW AREAS ABOVE 10500 FEET RECEIVING UP TO
3 INCHES. NOT EXPECTING MUCH TO STICK TO ANY ASPHALT ROADWAYS
HOWEVER.

.LONG TERM...MONDAY NIGHT THROUGH SUNDAY

MONDAY NIGHT AS THE TROUGH CONTINUE TO MOVE EAST...HIGH PRESSURE
RIDGING WILL OCCUR OVER THE PACIFIC NORTHWEST.  THE MAIN TREND WILL
BE FOR DRYING WITH BREEZY TO WINDY CONDITIONS ACROSS THE SOUTH INTO
CENTRAL AREAS.

TUESDAY AND TUESDAY NIGHT DRY HIGH PRESSURE IS EXPECTED TO DOMINATE
THE WEATHER ACROSS THE AREA WITH INCREASING WEST TO SOUTHWEST WINDS
CENTRAL AND SOUTH WITH GENERAL WARMING. TEMPERATURES SHOULD WARM.

WEDNESDAY AND WEDNESDAY NIGHT  SOME MID LEVEL CLOUDS ARE EXPECTED TO
MOVE UP FROM THE GREAT BASIN IN THE AFTERNOON...OTHERWISE THE DRY
HIGH PRESSURE IS EXPECTED TO CONTINUE TO DOMINATE THE WEATHER WITH
CONTINUED SOUTHWEST WINDS ACROSS THE CENTRAL AND SOUTH WITH THE
WARMING TREND CONTINUING.

THURSDAY AND THURSDAY NIGHT  HIGH PRESSURE WILL SHIFT EAST WITH
INCREASING SOUTHWEST FLOW ALOFT BRINGING SOME PACIFIC MOISTURE ALOFT
OVER THE AREA.  SHOWERS ARE EXPECTED TO DEVELOP WITH ISOLATED
THUNDERSTORMS IN THE AFTERNOON...MOST NUMEROUS OVER THE WESTERN AND
CENTRAL MOUNTAINS.  INCREASED CLOUD COVER  AND A COLD FRONT MOVING
SOUTH FROM MONTANA WILL BRING COOLING.  MODELS STRONGER WITH COLD
FRONT THAN YESTERDAY WITH MORE SIGNIFICANT COOLING.

FRIDAY AND FRIDAY NIGHT  SHOWERS AND ISOLATED THUNDERSTORMS ARE
EXPECTED TO INCREASE OVER THE AREA AS PACIFIC MOISTURE INCREASES IN
SOUTHWEST FLOW ALOFT.  A COLD FRONT WILL CONTINUE TO MOVE SOUTH
INTO SOUTHERN WYOMING.  AGAIN MODELS CONTINUE TO BE STRONGER WITH
THIS COLD FRONT AND ASSOCIATED COOLING BRINGING THE COLD AIR THROUGH
THE SOUTHWEST WHILE YESTERDAY THE FRONT DID NOT MIKE IT THROUGH
CENTRAL WYOMING.

SATURDAY AND SATURDAY NIGHT SOUTHWEST FLOW ALOFT WILL REMAIN IN
PLACE OVER THE AREA WITH A STREAM OF PACIFIC MOISTURE CONTINUING TO
ADVECT INTO THE AREA SUPPORTING SCATTERED SHOWERS AND SOME ISOLATED
AFTERNOON THUNDERSTORMS.  A FRONT IS EXPECTED TO REMAIN THROUGH
SOUTHERN WYOMING WITH CONTINUED COOLING.

SUNDAY SOME DRYING IS EXPECTED IN THE WEST WITH POSSIBLE WARMING.
OVERALL LOW CONFIDENCE IN FORECAST FOR SUNDAY AS THE SPREAD IN
SOLUTIONS WITH THE EXTENDED MODELS BECOMES MORE SIGNIFICANT.

&&

.AVIATION.../00Z ISSUANCE/

VFR WILL PREVAIL FOR MOST TERMINALS THROUGH THE FORECAST PERIOD. THE
EXCEPTIONS WILL BE KCOD WITH MVFR IN LOW CIGS AND POSSIBLE VIS
RESTRICTIONS THROUGH 18Z MONDAY. LARGE UPPER LEVEL TROUGH CONTINUES
TO EXPAND ACROSS THE COUNTRY WITH AN EMBEDDED DISTURBANCE MOVING
THROUGH THE TROUGH AND ACROSS EASTERN WYOMING THIS AFTERNOON AND
EVENING...EXITING INTO THE HIGH PLAINS BY TONIGHT. ANOTHER
DISTURBANCE WILL FOLLOW BETWEEN 06Z AND 18Z MONDAY...AFFECTING
MAINLY THE NORTHERN FORECAST AREA. ISOLATED TO SCATTERED SHOWERS AND
ISOLATED THUNDERSTORMS WILL CONTINUE ACROSS CENTRAL...EASTERN AND
NORTHERN WYOMING THROUGH 03Z BEFORE BECOMING MORE ISOLATED IN NATURE
FOR MOST LOCATIONS EXCEPT FOR THE NORTHWEST WHICH WILL REMAIN MORE
SCATTERED IN SHOWERS. YELLOWSTONE NATIONAL PARK TO VCNTY COD-BYG AND NORTH
WILL REMAIN MOST ACTIVE AND MOST LIABLE FOR MVFR CONDITIONS TO
PERSIST THROUGH 21Z. SNOW LEVELS WILL HOVER BETWEEN 9-10.5KFT ACROSS
NORTHERN WYOMING...WITH MOUNTAIN OBSCURATIONS AND AREAS OF MVFR TO
OCCASIONAL IFR CONDITIONS. THE OTHER AREA OF MORE ORGANIZED
SHRA/ISOLD TSRA COVERAGE WILL OCCUR FROM VCNTY AND NORTH OF A
KLND-KCPR LINE THROUGH THE THIS EVENING. HOWEVER...CONDITIONS WILL
GENERALLY IMPROVE FROM WEST TO EAST THROUGH THE EVENING. THERE WILL
BE A SLIGHT POSSIBILITY FOR PATCHY FOG DEVELOPING WHERE BETTER RAINS
HAVE FALLEN ESPECIALLY IN WESTERN/NORTHWESTERN MOUNTAIN/VALLEY
LOCATIONS...SUCH AS NEAR AND NORTH OF KJAC AFTER 10Z MONDAY. KCOD
WILL BE THE MOST LIKELY TO SEE SOME VIS REDUCTION DUE TO MIST/FOG AS
MORE PERSISTENT PRECIPITATION WILL CONTINUE IN AND AROUND THE AREA
OVER A LONGER PERIOD.

&&

.FIRE WEATHER...

FIRE DANGER WILL BE RELATIVELY LOW TODAY THROUGH TONIGHT. A LARGE
UPPER LEVEL TROUGH CONTINUES TO EXPAND ACROSS THE COUNTRY TODAY WITH
ANOTHER EMBEDDED DISTURBANCE MOVING THROUGH THE TROUGH AND ACROSS
WYOMING TODAY...THEN INTO THE HIGH PLAINS BY TONIGHT. ANOTHER
DISTURBANCE WILL FOLLOW BETWEEN BETWEEN MIDNIGHT AND EARLY AFTERNOON
MONDAY...AFFECTING MAINLY THE NORTHERN FORECAST ZONES. A SURFACE
FRONT/BOUNDARY LAYS ACROSS NATRONA COUNTY AND WEST INTO SOUTHERN
FREMONT COUNTY THEN NORTHERN SWEETWATER COUNTY. ISOLATED TO
SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS WILL CONTINUE ACROSS
CENTRAL...EASTERN AND NORTHERN WYOMING THROUGH THE AFTERNOON BEFORE
BECOMING MORE ISOLATED IN NATURE FOR MOST LOCATIONS EXCEPT FOR THE
NORTHWEST WHICH WILL CONTINUE MORE SCATTERED. SNOW LEVELS WILL HOVER
BETWEEN 9-10KFT ACROSS THE NORTH. SOUTH OF THE FRONT/BOUNDARY
MENTIONED ABOVE...WEST TO WEST SOUTHWEST WINDS CONTINUE TODAY AT
15-25 MPH WITH GUSTS 35 TO 40 MPH POSSIBLE ALONG WITH MINIMUM RH
VALUES ONLY DROPPING TO 35 PERCENT AT THE LOW END. ISOLATED ERRATIC
OUTFLOW WIND GUSTS NEAR 45KTS WILL BE POSSIBLE WITH A FEW STORMS
THIS AFTERNOON.

&&

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

$$

SHORT TERM...BRAUN
LONG TERM...C.BAKER
AVIATION...BRAUN
FIRE WEATHER...BRAUN






000
FXUS65 KCYS 311756
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
1156 AM MDT SUN AUG 31 2014

.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 345 AM MDT SUN AUG 31 2014

CURRENT KCYS RADAR LOOP SHOWS AN AREA OF RAIN SHOWERS AND EMBEDDED
THUNDERSTORMS QUICKLY MOVING EASTWARD ACROSS THE AREA EARLY THIS
MORNING. THIS ACTIVITY IS IN ADVANCE OF AN UPPER LEVEL TROUGH AXIS
MOVING INTO WESTERN WYOMING. 250 MB JET STREAM WINDS WILL CONTINUE
TO INCREASE THIS MORNING OVER 100 KNOTS AS THE SURFACE COLD FRONT
HAS JUST STARTED TO ACCELERATE SOUTHEAST ACROSS THE FORECAST AREA.
EXPECT A COOLER THAN AVERAGE DAY TODAY BEHIND THIS COLD FRONT AS
THE TROUGH AXIS MOVES ACROSS SOUTHEAST WYOMING...RESULTING IN
SURFACE TEMPERATURES IN THE UPPER 60S TO MID 70S ACROSS MOST OF
THE FORECAST AREA. IT WILL BE A LITTLE WARMER FURTHER SOUTH AND
EAST ACROSS THE SOUTHERN NEBRASKA PANHANDLE SINCE THE FRONT WILL
STALL LATER TODAY. SHOWERS AND ISOLATED THUNDERSTORMS ARE EXPECTED
THROUGH TODAY. THE GFS CONTINUES TO BE ON THE DRY SIDE EVEN THOUGH
THE RADAR IMAGERY THIS MORNING HAS BEEN ACTIVE. WITH A STRONG JET
OVERHEAD...BELIEVE MODELS CONTINUE TO DOWNPLAY THE CHANCES FOR
WIDESPREAD SHOWERS TODAY. KEPT POP BETWEEN 40 TO 60 PERCENT FOR
SCATTERED SHOWERS AND ISOLATED THUNDER INTO THIS EVENING. WINDY
CONDITIONS ARE EXPECTED THIS AFTERNOON AFTER FROPA...WITH GUSTS UP
TO 45 MPH POSSIBLE WEST OF THE LARAMIE RANGE. WINDS WILL STRUGGLE
TO REACH 30 MPH OVER THE NEBRASKA PANHANDLE THIS AFTERNOON. SHOWER
ACTIVITY WILL QUICKLY COME TO AND END EARLY THIS EVENING AS DRIER
AND MORE STABLE AIR MOVE INTO THE REGION. SKIES WILL QUICKLY CLEAR
TONIGHT WITH CHILLY OVERNIGHT LOWS IN THE 30S TO MID 40S EXPECTED.

ANOTHER COOL DAY EXPECTED ON MONDAY WITH HIGHS STRUGGLING TO
REACH THE LOW TO MID 70S ACROSS MOST OF THE AREA. MODELS SHOW A
SECONDARY SHORTWAVE QUICKLY PUSHING ACROSS THE AREA...RESULTING IN
SOME RAIN SHOWER ACTIVITY AND MAYBE A FEW LIGHTNING STRIKES.

UPPER LEVEL FLOW BECOMES MORE ZONAL FOR TUESDAY WITH INCREASING
TEMPERATURES INTO THE UPPER 70S TO MID 80S ACROSS THE AREA. DRIER
AIR WILL PUSH INTO THE REGION WITH PW/S LOWERING BELOW ONE HALF
INCH DURING THE DAY.

.LONG TERM...(TUESDAY NIGHT THROUGH SATURDAY)
ISSUED AT 300 AM MDT SUN AUG 31 2014

THE LONG TERM FORECAST WILL START OFF DRY AND BREEZY WEDNESDAY UNDER
ZONAL FLOW ACROSS THE CONUS. DOWNSLOPE FLOW WILL PUSH TEMPERATURES
INTO THE 80S ACROSS SOUTHEAST WYOMING AND 90S INTO THE PANHANDLE. BY
THURSDAY AN UPPER LEVEL TROUGH WILL DIG OVER THE PACIFIC NORTHWEST
WITH SOUTHWEST FLOW KICKING IN ACROSS THE CENTRAL AND NORTHERN
ROCKIES. WILL START TO SEE INCREASING CHANCES FOR SHOWERS AND
THUNDERSTORMS LATE THURSDAY AND THEN INTO THURSDAY NIGHT. THURSDAY
SHOULD BE A BIT COOLER AS MID AND UPPER LEVEL CLOUD COVER LIMITS
DEEPER MIXING.

FORECAST MUCH MORE TRICKY FRIDAY AND SATURDAY AS MODEL SOLUTIONS
DIVERGE. GFS DEVELOPS A SLOW MOVING CLOSE LOW OVER THE WESTERN CONUS
WITH RELATIVELY DRY SOUTHWEST FLOW FOR THE FORECAST AREA. THE ECMWF
ON THE OTHER HAND SHOWS A MORE PROGRESSIVE WAVE SUPPRESSING THE RIDGE
OVER THE ROCKIES FRIDAY AND THEN DEVELOPING NORTHWEST FLOW BY
SATURDAY. IN OTHER WORDS THE ECMWF IS NOT ONLY COOLER BUT WOULD ALSO
SUGGESTS INCREASED PRECIPITATION CHANCES. NOT COMPLETELY CONFIDENT IN
EITHER MODEL BUT LEANING TOWARD THE ECMWF AS OVERALL WEATHER PATTERN
PERSISTENCE GOING ALL THE WAY BACK TO LAST WINTER FAVORS NORTHWEST
FLOW.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY MORNING)
ISSUED AT 1146 AM MDT SUN AUG 31 2014

SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS WILL BE POSSIBLE
THROUGH THE AFTERNOON. MUCH OF THE ACTIVITY WILL SHIFT EASTWARD
OUT OF SOUTHEAST WY BY LATE AFTERNOON. MODERATE RAIN WILL
ACCOMPANY SOME OF THE STRONGER SHOWERS...WITH BRIEF MVFR VIS
POSSIBLE. WEST TO NORTHWEST WINDS WILL BE BREEZY THROUGH 00Z OVER
MUCH OF SOUTHEAST WY WITH GUSTS TO 30 KTS.

&&

.FIRE WEATHER...
ISSUED AT 244 AM MDT SUN AUG 31 2014

NO FIRE WEATHER CONCERNS THROUGH MONDAY...BUT THEN CONCERN OF NEAR
CRITICAL CONDITIONS INCREASE FOR TUESDAY AND WEDNESDAY. A STRONG
WEATHER DISTURBANCE AND ASSOCIATED COLD FRONT WILL MOVE ACROSS
THE AREA EARLY THIS MORNING. SHOWERS AND TSTORMS WILL CONTINUE
ACROSS SOUTHEAST WYOMING AND WESTERN NEBRASKA TODAY WITH GUSTY
WEST TO SOUTHWEST WINDS. DRIER CONDITIONS WILL DEVELOP BY MIDDLE
OF NEXT WEEK WHILE GUSTY WEST WINDS CONTINUE IN AREAS ALONG AND
WEST OF THE LARAMIE RANGE.

&&

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

$$

SHORT TERM...TJT
LONG TERM...SML
AVIATION...FINCH
FIRE WEATHER...TJT




000
FXUS65 KCYS 311756
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
1156 AM MDT SUN AUG 31 2014

.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 345 AM MDT SUN AUG 31 2014

CURRENT KCYS RADAR LOOP SHOWS AN AREA OF RAIN SHOWERS AND EMBEDDED
THUNDERSTORMS QUICKLY MOVING EASTWARD ACROSS THE AREA EARLY THIS
MORNING. THIS ACTIVITY IS IN ADVANCE OF AN UPPER LEVEL TROUGH AXIS
MOVING INTO WESTERN WYOMING. 250 MB JET STREAM WINDS WILL CONTINUE
TO INCREASE THIS MORNING OVER 100 KNOTS AS THE SURFACE COLD FRONT
HAS JUST STARTED TO ACCELERATE SOUTHEAST ACROSS THE FORECAST AREA.
EXPECT A COOLER THAN AVERAGE DAY TODAY BEHIND THIS COLD FRONT AS
THE TROUGH AXIS MOVES ACROSS SOUTHEAST WYOMING...RESULTING IN
SURFACE TEMPERATURES IN THE UPPER 60S TO MID 70S ACROSS MOST OF
THE FORECAST AREA. IT WILL BE A LITTLE WARMER FURTHER SOUTH AND
EAST ACROSS THE SOUTHERN NEBRASKA PANHANDLE SINCE THE FRONT WILL
STALL LATER TODAY. SHOWERS AND ISOLATED THUNDERSTORMS ARE EXPECTED
THROUGH TODAY. THE GFS CONTINUES TO BE ON THE DRY SIDE EVEN THOUGH
THE RADAR IMAGERY THIS MORNING HAS BEEN ACTIVE. WITH A STRONG JET
OVERHEAD...BELIEVE MODELS CONTINUE TO DOWNPLAY THE CHANCES FOR
WIDESPREAD SHOWERS TODAY. KEPT POP BETWEEN 40 TO 60 PERCENT FOR
SCATTERED SHOWERS AND ISOLATED THUNDER INTO THIS EVENING. WINDY
CONDITIONS ARE EXPECTED THIS AFTERNOON AFTER FROPA...WITH GUSTS UP
TO 45 MPH POSSIBLE WEST OF THE LARAMIE RANGE. WINDS WILL STRUGGLE
TO REACH 30 MPH OVER THE NEBRASKA PANHANDLE THIS AFTERNOON. SHOWER
ACTIVITY WILL QUICKLY COME TO AND END EARLY THIS EVENING AS DRIER
AND MORE STABLE AIR MOVE INTO THE REGION. SKIES WILL QUICKLY CLEAR
TONIGHT WITH CHILLY OVERNIGHT LOWS IN THE 30S TO MID 40S EXPECTED.

ANOTHER COOL DAY EXPECTED ON MONDAY WITH HIGHS STRUGGLING TO
REACH THE LOW TO MID 70S ACROSS MOST OF THE AREA. MODELS SHOW A
SECONDARY SHORTWAVE QUICKLY PUSHING ACROSS THE AREA...RESULTING IN
SOME RAIN SHOWER ACTIVITY AND MAYBE A FEW LIGHTNING STRIKES.

UPPER LEVEL FLOW BECOMES MORE ZONAL FOR TUESDAY WITH INCREASING
TEMPERATURES INTO THE UPPER 70S TO MID 80S ACROSS THE AREA. DRIER
AIR WILL PUSH INTO THE REGION WITH PW/S LOWERING BELOW ONE HALF
INCH DURING THE DAY.

.LONG TERM...(TUESDAY NIGHT THROUGH SATURDAY)
ISSUED AT 300 AM MDT SUN AUG 31 2014

THE LONG TERM FORECAST WILL START OFF DRY AND BREEZY WEDNESDAY UNDER
ZONAL FLOW ACROSS THE CONUS. DOWNSLOPE FLOW WILL PUSH TEMPERATURES
INTO THE 80S ACROSS SOUTHEAST WYOMING AND 90S INTO THE PANHANDLE. BY
THURSDAY AN UPPER LEVEL TROUGH WILL DIG OVER THE PACIFIC NORTHWEST
WITH SOUTHWEST FLOW KICKING IN ACROSS THE CENTRAL AND NORTHERN
ROCKIES. WILL START TO SEE INCREASING CHANCES FOR SHOWERS AND
THUNDERSTORMS LATE THURSDAY AND THEN INTO THURSDAY NIGHT. THURSDAY
SHOULD BE A BIT COOLER AS MID AND UPPER LEVEL CLOUD COVER LIMITS
DEEPER MIXING.

FORECAST MUCH MORE TRICKY FRIDAY AND SATURDAY AS MODEL SOLUTIONS
DIVERGE. GFS DEVELOPS A SLOW MOVING CLOSE LOW OVER THE WESTERN CONUS
WITH RELATIVELY DRY SOUTHWEST FLOW FOR THE FORECAST AREA. THE ECMWF
ON THE OTHER HAND SHOWS A MORE PROGRESSIVE WAVE SUPPRESSING THE RIDGE
OVER THE ROCKIES FRIDAY AND THEN DEVELOPING NORTHWEST FLOW BY
SATURDAY. IN OTHER WORDS THE ECMWF IS NOT ONLY COOLER BUT WOULD ALSO
SUGGESTS INCREASED PRECIPITATION CHANCES. NOT COMPLETELY CONFIDENT IN
EITHER MODEL BUT LEANING TOWARD THE ECMWF AS OVERALL WEATHER PATTERN
PERSISTENCE GOING ALL THE WAY BACK TO LAST WINTER FAVORS NORTHWEST
FLOW.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY MORNING)
ISSUED AT 1146 AM MDT SUN AUG 31 2014

SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS WILL BE POSSIBLE
THROUGH THE AFTERNOON. MUCH OF THE ACTIVITY WILL SHIFT EASTWARD
OUT OF SOUTHEAST WY BY LATE AFTERNOON. MODERATE RAIN WILL
ACCOMPANY SOME OF THE STRONGER SHOWERS...WITH BRIEF MVFR VIS
POSSIBLE. WEST TO NORTHWEST WINDS WILL BE BREEZY THROUGH 00Z OVER
MUCH OF SOUTHEAST WY WITH GUSTS TO 30 KTS.

&&

.FIRE WEATHER...
ISSUED AT 244 AM MDT SUN AUG 31 2014

NO FIRE WEATHER CONCERNS THROUGH MONDAY...BUT THEN CONCERN OF NEAR
CRITICAL CONDITIONS INCREASE FOR TUESDAY AND WEDNESDAY. A STRONG
WEATHER DISTURBANCE AND ASSOCIATED COLD FRONT WILL MOVE ACROSS
THE AREA EARLY THIS MORNING. SHOWERS AND TSTORMS WILL CONTINUE
ACROSS SOUTHEAST WYOMING AND WESTERN NEBRASKA TODAY WITH GUSTY
WEST TO SOUTHWEST WINDS. DRIER CONDITIONS WILL DEVELOP BY MIDDLE
OF NEXT WEEK WHILE GUSTY WEST WINDS CONTINUE IN AREAS ALONG AND
WEST OF THE LARAMIE RANGE.

&&

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

$$

SHORT TERM...TJT
LONG TERM...SML
AVIATION...FINCH
FIRE WEATHER...TJT





000
FXUS65 KRIW 311711
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
1111 AM MDT SUN AUG 31 2014

.SHORT TERM...TODAY THROUGH TUESDAY NIGHT

SHOWERS AND STORMS ONGOING AS A DYNAMIC TROUGH CONTINUES TO MOVE
THROUGH THE REGION. A COLD FRONT MOVED THROUGH ON SATURDAY WITH
ANOTHER REINFORCING COLD FRONT MOVING THROUGH FROM NORTHWEST TO
SOUTHEAST DURING THE MORNING HOURS...IT WILL BE COLD ENOUGH FOR SNOW
ABOVE 9KFT BEHIND THIS FRONT ESPECIALLY DURING THE MORNING HOURS.
ELSEWHERE...SCATTERED RAIN SHOWERS WITH EMBEDDED THUNDER THROUGHOUT
THE DAY WITH PERHAPS MORE OF AN EARLY SHOW OUT WEST GIVEN THE
EXPECTED TIMING OF THE TROUGH...HOWEVER THERE WILL BE ANOTHER WAVE
MOVING THROUGH LATE...BRINGING INCREASED SHOWER ACTIVITY BACK INTO
THE NORTHWEST AFTER SUNSET. SO A RATHER COMPLEX TROUGH WITH MANY
PIECES AND PARTS STILL EXPECTED TO AFFECT THE REGION THROUGH
TONIGHT. STRONGER STORMS WITH SMALL HAIL AND GUSTY WINDS WILL BE
MOST PROBABLE ACROSS NATRONA...EASTERN FREMONT AND SWEETWATER
COUNTIES NEAR A FRONTAL BOUNDARY BUT THERE WILL BE LESS CAPE AND
SHEAR TO WORK WITH TODAY SO NO SEVERE STORMS ARE EXPECTED.
OTHERWISE...MOST IF NOT ALL OF THE FORECAST AREA SHOULD SEE ANOTHER
STORM OR TWO BY TONIGHT.

ASIDE FROM THE RAIN CHANCES...IT WILL BE RATHER WINDY AGAIN TODAY AS
THE GRADIENT REMAINS TIGHT AND THUNDERSTORMS WILL STILL SEND OUT
SOME DECENT OUTFLOWS...THOUGH THEY ARE NOT EXPECTED TO BE AS STRONG
AS THEY WERE ON SATURDAY.

LABOR DAY...THE LAST SHORT WAVE THAT COULD STIR UP MORE SHOWERS AND
STORMS MOVES THROUGH EARLY IN THE DAY WITH EVENTUAL CLEARING AS THE
TROUGH CONTINUES TO MOVE EAST. THERE WILL ALSO BE SOME CONTINUED
BREEZY CONDITIONS AS THE SUBSIDENT SIDE OF THE TROUGH SWINGS THROUGH
AND FLOW SHIFTS TO THE NORTHWEST.

MUCH DRIER AIR MOVES IN ON TUESDAY AS FLOW TURNS MORE ZONAL. HIGH
PRESSURE BUILDING IN FROM THE SOUTH WILL ALSO BRING SOME WARMER AIR
WITH TEMPERATURES REBOUNDING BACK INTO THE 80S EAST OF THE DIVIDE.
THERE COULD BE SOME GUSTS TO 30 MPH ACROSS THE SOUTH ON
TUESDAY...WHICH COULD LEAD TO SOME FIRE WEATHER CONCERNS IN AREAS
WITH FLASHY GRASSY FUELS.

.LONG TERM...WEDNESDAY THROUGH SUNDAY

WEDNESDAY WILL BE DRY FOR MOST OF THE REGION. ISOLATED SHOWERS OR
STORMS FOR THE WESTERN MOUNTAINS AND NORTHERN MOUNTAINS. BREEZY
TO WINDY AREAS AND A WARM DAY. ISOLATED SHOWERS AND STORMS OVER
THE NORTH AND NORTHWEST WED NIGHT AS A TROUGH DEVELOPS OVER THE
PACIFIC NW EAST INTO MONTANA. THIS ELONGATED TROUGH WILL BE THE
FOCUS OF THE WEATHER THURSDAY THROUGH SUNDAY PER THE GFS MODEL.
THE ECMWF IS ALSO SHOWING THIS PATTERN THROUGH SATURDAY BUT MOVES
THE SYSTEM OUT FOR NEXT SUNDAY. A COLD FRONT PUSHES SOUTH INTO
NORTHERN WY LATE WED NIGHT AND THEN CONTINUES TO PUSH SOUTH ON
THURSDAY. THE FRONT LIES ALONG THE CONTINENTAL DIVIDE THURSDAY PM
PER THE GFS WHILE THE ECMWF MOVES IT THROUGH THE WHOLE AREA
THURSDAY. THUS THE FORECAST DILEMMA FOR HIGHS ON THURSDAY. PLUS
THE ECMWF IS COLDER WITH TEMPS ALOFT AND NEAR SURFACE TEMPS THAN
THE GFS THURSDAY...AS WELL AS FRIDAY AND SATURDAY. HAVE BLENDED
THE FORECAST HIGHS AND LOWS THURSDAY THROUGH SATURDAY KEEPING THE
BETTER COOLING EAST OF THE DIVIDE. MOISTURE IS FORECAST TO
INCREASE OVER THE REGION THURSDAY THROUGH SATURDAY IN A SW FLOW
ALOFT. MOISTURE SEEMS TO COME FROM TWO SOURCES...ONE FROM THE
TROUGH TO THE NORTH...THE OTHER FROM THE SW U.S. AROUND THE UPPER
HIGH. FOR NOW HAVE THE TYPICAL ISOLATED TO (IN SOME CASES)
SCATTERED SHOWERS AND STORMS OVER THE REGION THURSDAY THROUGH
SATURDAY. THE FRONTAL BOUNDARY WILL ALSO PLAY A ROLE IN THE PRECIP
CHANCE. OVERALL...A COMPLEX PATTERN FOR THOSE THREE DAYS. NEXT
SUNDAY LOOKS LIKE ISOLATED SHOWERS/STORMS AND WARMER HIGHS MOST
PLACES.

&&

.AVIATION.../18Z ISSUANCE/

VFR WILL PREVAIL FOR MOST TERMINALS THROUGH THE FORECAST PERIOD. THE
EXCEPTIONS WILL BE KJAC THROUGH 22Z WITH PERIODS OF MVFR IN LOW CIGS
AND KCOD WITH MVFR IN LOW CIGS AND POSSIBLE VIS RESTRICTIONS
OCCASIONALLY THROUGH 16Z MONDAY. LARGE UPPER LEVEL TROUGH CONTINUES
TO EXPAND ACROSS THE COUNTRY TODAY WITH ANOTHER EMBEDDED DISTURBANCE
MOVING ACROSS WYOMING THIS TODAY...THEN INTO THE HIGH PLAINS BY 00Z
MONDAY...WITH ANOTHER TO FOLLOW BETWEEN 06Z AND 18Z
MONDAY...AFFECTING MAINLY THE NORTHERN FORECAST AREA. ISOLATED TO
SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS WILL CONTINUE ACROSS
CENTRAL AND NORTHERN WYOMING THROUGH 00Z BEFORE BECOMING MORE
ISOLATED IN NATURE FOR MOST LOCATIONS EXCEPT FOR THE NORTHWEST WHICH
WILL REMAIN MORE SCATTERED. YELLOWSTONE NATIONAL PARK TO VCNTY
COD-BYG AND NORTH WILL REMAIN MOST ACTIVE AND MOST LIABLE FOR MVFR
CONDITIONS TO PERSIST. SNOW LEVELS WILL HOVER BETWEEN 9-10KFT IN
ACROSS THE NORTH...WITH MOUNTAIN OBSCURATIONS AND AREAS OF MVFR TO
OCCASIONAL IFR CONDITIONS. THE OTHER AREA OF MORE ORGANIZED
SHRA/ISOLD TSRA COVERAGE IS EXPECTED FROM VCNTY AND NORTH OF A
KJAC-KRIW-KCPR LINE THROUGH THE AFTERNOON AND EARLY EVENING.
HOWEVER...CONDITIONS WILL GENERALLY IMPROVE FROM WEST TO EAST
THROUGH THE AFTERNOON AND EVENING. THERE WILL BE A SLIGHT
POSSIBILITY FOR PATCHY FOG DEVELOPING WHERE BETTER RAINS HAVE FALLEN
ESPECIALLY IN WESTERN/NORTHWESTERN MOUNTAIN/VALLEY LOCATIONS...SUCH
AS NEAR KJAC AFTER 10Z MONDAY. KCOD MAY BE THE MOST LIKELY TO SEE
SOME VIS REDUCTION DUE TO MIST/FOG AS MORE PERSISTENT PRECIPITATION
WILL CONTINUE IN AND AROUND THE AREA OVER A LONGER PERIOD.

&&

.FIRE WEATHER...

SHOWERS AND THUNDERSTORMS WITH A GOOD CHANCE OF WETTING RAIN
POSSIBLE ACROSS THE ENTIRE FORECAST AREA AGAIN TODAY. A COLD FRONT
MOVING THROUGH EARLY THIS MORNING WILL BRING ANOTHER CHANCE FOR SNOW
ABOVE 9KFT IN THE NORTHERN MOUNTAINS. THERE WILL BE A LULL IN THE
ACTIVITY FROM WEST TO EAST THIS AFTERNOON INTO THE EVENING BEFORE
THE NEXT WAVE MOVES IN...HOWEVER THIS WAVE WILL BE LESS IMPACTFUL
WITH ONLY A FEW SHOWERS AND STORMS EXPECTED ACROSS THE NORTHERN
THIRD OF THE STATE. IT WILL BE WINDY AGAIN TODAY...THOUGH NOT AS
GUSTY AS SATURDAY. TEMPERATURES WILL BE LOWER AND HUMIDITY HIGHER
TODAY WITH PLENTY OF CLOUD COVER...SO FIRE DANGER WILL BE LOW. IT
WILL BEGIN TO DRY OUT ON MONDAY...ESPECIALLY ACROSS THE SOUTH...BUT
CONTINUED COOL AND WINDY. MUCH WARMER AND DRIER AIR MOVES IN ON
TUESDAY WITH A STEADY WESTERLY WIND OF 20 TO 30 MPH ACROSS MUCH OF
RAWLINS AND CASPER DISPATCH WITH FIRE WEATHER CONCERNS POSSIBLY
RISING A BIT IF THE RH CAN DROP LOW ENOUGH.

&&

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

&&

$$

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











000
FXUS63 KUNR 311658
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
1058 AM MDT SUN AUG 31 2014

.UPDATE...
ISSUED AT 940 AM MDT SUN AUG 31 2014

CURRENT SURFACE ANALYSIS SHOWS LOW PRESSURE OVER SOUTHEAST
ND...WITH COLD FRONT WELL EAST OF OUR FORECAST AREA. UPPER LEVEL
ANALYSIS SHOWS BROAD TROF OVER THE WESTERN CONUS...WITH A SERIES
OF SHORTWAVES WITHIN THE TROF MOVING EAST THROUGH THE ROCKIES AND
PLAINS. LAST NIGHTS WAVE HAS MOVED WELL EAST OF THE AREA...BUT
ANOTHER IS MOVING THROUGH WESTERN NEB INTO PORTIONS OF SOUTHWEST
AND SOUTH CENTRAL SD NOW. YET ANOTHER DISTURBANCE IS NOTED OVER
WESTERN INTO CENTRAL WY...MOVING QUICKLY EASTWARD. KUDX RADAR
SHOWS BULK OF SHOWER ACTIVITY RIGHT NOW IS LOCATED OVER FAR
SOUTHWEST INTO SOUTH CENTRAL SD...WITH ISOLATED SHOWERS ELSEWHERE
TO THE NORTH AND WEST. TEMPS ARE IN THE UPPER 50S AND 60S ACROSS
MOST OF THE AREA WITH LIGHT WEST TO NORTHWEST WINDS.

SHOWERS AND ISOLATED THUNDERSTORMS OVER SOUTHEASTERN PORTIONS OF
THE CWA WILL MOVE EAST THROUGH THE LATE MORNING AND MIDDAY HOURS
AND EVENTUALLY EXIT EAST OF THE AREA. HOWEVER...SHOWERS AND
ISOLATED STORMS WILL CONTINUE TO DEVELOP AND INCREASE IN COVERAGE
FROM WEST TO EAST THROUGH THE MIDDAY AND AFTERNOON HOURS AS THE WY
SYSTEM MOVES EAST OVER THE AREA. THE BEST CHANCES FOR SHOWERS AND
MORE SIGNIFICANT RAINFALL WILL GENERALLY BE OVER THE BLACK HILLS
AREA AND SURROUNDING PLAINS. WITH CLOUD COVER AND RELATIVE LACK OF
WARMING TODAY...THE THREAT FOR SEVERE WEATHER SHOULD BE MINIMAL AT
BEST...WITH A STRONG STORM POSSIBLE OVER FAR SOUTHWEST AND SOUTH
CENTRAL SD THIS AFTERNOON. HIGHS WILL MOSTLY BE IN THE 70S ACROSS
THE SD PLAINS...WITH 60S OVER NORTHEAST WY AND THE BLACK HILLS.
SHOWERS WITH THIS SYSTEM SHOULD GRADUALLY DISSIPATE AND MOVE EAST
OF THE AREA DURING THE EVENING.

HAVE UPDATED TO RAISE POPS OVER MUCH OF THE AREA THROUGH THE DAY
AND TO LOWER HIGH TEMPS A BIT OVER EASTERN AREAS. ALSO MADE
ADJUSTMENTS TO CLOUD COVER AND DEWPOINTS THROUGH THE AFTERNOON.

&&

.SHORT TERM...TODAY THROUGH MONDAY NIGHT
ISSUED AT 300 AM MDT SUN AUG 31 2014

LONGWAVE TROUGH AXIS IS CROSSING MT SOUTH TO WY WITH SEVERAL
EMBEDDED WAVES ROUNDING THE BASE OVER WY. IR SAT/NEIGHBORING RADAR
SHOWS SHRA OVER WY QUICKLY PUSHING EWD. MEANWHILE OVER THE
CWA...SMALL SCALE SUBSIDENCE BEHIND THE WAVE DEPARTING E OF THE CWA
IS LEAVING QUIET WEATHER OVER THE AREA ATTM. THE TROUGH AXIS WILL
CROSS THE CWA TODAY BRINGING SHRA/TSRA TO THE AREA. MLCAPE WILL BE
WEAKER THAN YESTERDAY...500 TO 1000 J/KG TODAY WITH LITTLE TO NO
CAP...STILL ENOUGH FOR SOME STORM DEVELOPMENT. STRONG FORCING W/
THIS WAVE WARRANTS KEEPING AND EXPANDING LIKELY POPS OVER MUCH OF
THE CWA. GIVEN THE SPEED OF THIS SYSTEM...QPF IS EXPECTED TO BE
UNDER A HALF INCH. TEMPERATURES WILL BE A COOL 60S OVER NE WY AND
THE BLACK HILLS...ESPECIALLY AS CLOUDS REMAIN OVER THOSE AREA MUCH
OF THE DAY. THE SD PLAINS ARE EXPECTED TO REACH INTO THE 70S AND
MORNING HEATING COMMENCES BEFORE THE CLOUDS ROLL IN. BREEZY NW
WINDS WILL DEVELOP AS THE SYSTEM MOVES THROUGH WITH REINFORCING
COLD AIR ADVECTION.

SEVERAL UPPER WAVES DIVING DOWN THE BACKSIDE OF THE UPPER TROUGH
OVER THE NRN ROCKIES REGION WILL SLOW DOWN THE EWD PROGRESSION OF
THE OVERALL PATTERN. A SERIES OF WAVES ARE PROGGED TO CROSS THE CWA
MONDAY...WITH A REPEAT OF SHOWERS/STORMS CROSSING THE AREA THROUGH
THE DAY. WITH WEAKER FORCING AND LESS MOISTURE IN THE
ATMOSPHERE...WILL GO WITH CHANCE POPS FOR SHRA ACTIVITY. MLCAPE WILL
BE WEAKER MONDAY THAN TODAY...BUT COULD STILL SEE ISOLATED STORMS.
TEMPERATURES WILL BE IN THE MID 60S TO UPPER 70S. PRECIP WILL END
OVER THE AREA BY LATE MON NIGHT.

&&

.LONG TERM...TUESDAY THROUGH SATURDAY
ISSUED AT 300 AM MDT SUN AUG 31 2014

UPPER TROUGH DIGS ACROSS THE PACIFIC NORTHWEST TUESDAY/WEDNESDAY...
BRINGING FLAT UPPER RIDGE OVER THE NORTHERN PLAINS. THIS WILL
RESULT IN DRY CONDITIONS WITH TEMPERATURES NEAR OR SLIGHTLY ABOVE
AVERAGE. STRONG WAVE LIFTS ACROSS THE NORTHERN ROCKIES LATE
WEDNESDAY/THURSDAY...PUSHING COLD FRONT THROUGH THE NORTHERN
PLAINS. BEST FORCING STAYS NORTH OF FORECAST AREA...THOUGH A FEW
POST FRONTAL SHOWERS/THUNDERSTORMS POSSIBLE THURSDAY. MODELS
DIVERGE FOR THE WEEKEND...WITH ECMWF BRINGING STRONG SHORTWAVE IN
NORTHWEST FLOW SATURDAY...WHILE GFS MAINTAINS UPPER TROF OVER
WESTERN CONUS AND RIDGING OVER THE PLAINS. TRENDED TOWARDS
ECMWF...WITH COOLER TEMPERATURES AND SMALL POPS.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY)
ISSUED AT 1056 AM MDT SUN AUG 31 2014

SHOWERS AND THUNDERSTORMS WILL BE FOUND ACROSS THE AREA THROUGH
MONDAY MORNING. THE BEST COVERAGE WILL BE LATER THIS AFTERNOON AND
EARLY THIS EVENING. LOCAL MVFR CIGS/IFR VSBYS POSSIBLE WITH THE
STRONGER SHOWERS/STORMS.

&&

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

$$

UPDATE...26
SHORT TERM...13
LONG TERM...7
AVIATION...HELGESON





000
FXUS63 KUNR 311658
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
1058 AM MDT SUN AUG 31 2014

.UPDATE...
ISSUED AT 940 AM MDT SUN AUG 31 2014

CURRENT SURFACE ANALYSIS SHOWS LOW PRESSURE OVER SOUTHEAST
ND...WITH COLD FRONT WELL EAST OF OUR FORECAST AREA. UPPER LEVEL
ANALYSIS SHOWS BROAD TROF OVER THE WESTERN CONUS...WITH A SERIES
OF SHORTWAVES WITHIN THE TROF MOVING EAST THROUGH THE ROCKIES AND
PLAINS. LAST NIGHTS WAVE HAS MOVED WELL EAST OF THE AREA...BUT
ANOTHER IS MOVING THROUGH WESTERN NEB INTO PORTIONS OF SOUTHWEST
AND SOUTH CENTRAL SD NOW. YET ANOTHER DISTURBANCE IS NOTED OVER
WESTERN INTO CENTRAL WY...MOVING QUICKLY EASTWARD. KUDX RADAR
SHOWS BULK OF SHOWER ACTIVITY RIGHT NOW IS LOCATED OVER FAR
SOUTHWEST INTO SOUTH CENTRAL SD...WITH ISOLATED SHOWERS ELSEWHERE
TO THE NORTH AND WEST. TEMPS ARE IN THE UPPER 50S AND 60S ACROSS
MOST OF THE AREA WITH LIGHT WEST TO NORTHWEST WINDS.

SHOWERS AND ISOLATED THUNDERSTORMS OVER SOUTHEASTERN PORTIONS OF
THE CWA WILL MOVE EAST THROUGH THE LATE MORNING AND MIDDAY HOURS
AND EVENTUALLY EXIT EAST OF THE AREA. HOWEVER...SHOWERS AND
ISOLATED STORMS WILL CONTINUE TO DEVELOP AND INCREASE IN COVERAGE
FROM WEST TO EAST THROUGH THE MIDDAY AND AFTERNOON HOURS AS THE WY
SYSTEM MOVES EAST OVER THE AREA. THE BEST CHANCES FOR SHOWERS AND
MORE SIGNIFICANT RAINFALL WILL GENERALLY BE OVER THE BLACK HILLS
AREA AND SURROUNDING PLAINS. WITH CLOUD COVER AND RELATIVE LACK OF
WARMING TODAY...THE THREAT FOR SEVERE WEATHER SHOULD BE MINIMAL AT
BEST...WITH A STRONG STORM POSSIBLE OVER FAR SOUTHWEST AND SOUTH
CENTRAL SD THIS AFTERNOON. HIGHS WILL MOSTLY BE IN THE 70S ACROSS
THE SD PLAINS...WITH 60S OVER NORTHEAST WY AND THE BLACK HILLS.
SHOWERS WITH THIS SYSTEM SHOULD GRADUALLY DISSIPATE AND MOVE EAST
OF THE AREA DURING THE EVENING.

HAVE UPDATED TO RAISE POPS OVER MUCH OF THE AREA THROUGH THE DAY
AND TO LOWER HIGH TEMPS A BIT OVER EASTERN AREAS. ALSO MADE
ADJUSTMENTS TO CLOUD COVER AND DEWPOINTS THROUGH THE AFTERNOON.

&&

.SHORT TERM...TODAY THROUGH MONDAY NIGHT
ISSUED AT 300 AM MDT SUN AUG 31 2014

LONGWAVE TROUGH AXIS IS CROSSING MT SOUTH TO WY WITH SEVERAL
EMBEDDED WAVES ROUNDING THE BASE OVER WY. IR SAT/NEIGHBORING RADAR
SHOWS SHRA OVER WY QUICKLY PUSHING EWD. MEANWHILE OVER THE
CWA...SMALL SCALE SUBSIDENCE BEHIND THE WAVE DEPARTING E OF THE CWA
IS LEAVING QUIET WEATHER OVER THE AREA ATTM. THE TROUGH AXIS WILL
CROSS THE CWA TODAY BRINGING SHRA/TSRA TO THE AREA. MLCAPE WILL BE
WEAKER THAN YESTERDAY...500 TO 1000 J/KG TODAY WITH LITTLE TO NO
CAP...STILL ENOUGH FOR SOME STORM DEVELOPMENT. STRONG FORCING W/
THIS WAVE WARRANTS KEEPING AND EXPANDING LIKELY POPS OVER MUCH OF
THE CWA. GIVEN THE SPEED OF THIS SYSTEM...QPF IS EXPECTED TO BE
UNDER A HALF INCH. TEMPERATURES WILL BE A COOL 60S OVER NE WY AND
THE BLACK HILLS...ESPECIALLY AS CLOUDS REMAIN OVER THOSE AREA MUCH
OF THE DAY. THE SD PLAINS ARE EXPECTED TO REACH INTO THE 70S AND
MORNING HEATING COMMENCES BEFORE THE CLOUDS ROLL IN. BREEZY NW
WINDS WILL DEVELOP AS THE SYSTEM MOVES THROUGH WITH REINFORCING
COLD AIR ADVECTION.

SEVERAL UPPER WAVES DIVING DOWN THE BACKSIDE OF THE UPPER TROUGH
OVER THE NRN ROCKIES REGION WILL SLOW DOWN THE EWD PROGRESSION OF
THE OVERALL PATTERN. A SERIES OF WAVES ARE PROGGED TO CROSS THE CWA
MONDAY...WITH A REPEAT OF SHOWERS/STORMS CROSSING THE AREA THROUGH
THE DAY. WITH WEAKER FORCING AND LESS MOISTURE IN THE
ATMOSPHERE...WILL GO WITH CHANCE POPS FOR SHRA ACTIVITY. MLCAPE WILL
BE WEAKER MONDAY THAN TODAY...BUT COULD STILL SEE ISOLATED STORMS.
TEMPERATURES WILL BE IN THE MID 60S TO UPPER 70S. PRECIP WILL END
OVER THE AREA BY LATE MON NIGHT.

&&

.LONG TERM...TUESDAY THROUGH SATURDAY
ISSUED AT 300 AM MDT SUN AUG 31 2014

UPPER TROUGH DIGS ACROSS THE PACIFIC NORTHWEST TUESDAY/WEDNESDAY...
BRINGING FLAT UPPER RIDGE OVER THE NORTHERN PLAINS. THIS WILL
RESULT IN DRY CONDITIONS WITH TEMPERATURES NEAR OR SLIGHTLY ABOVE
AVERAGE. STRONG WAVE LIFTS ACROSS THE NORTHERN ROCKIES LATE
WEDNESDAY/THURSDAY...PUSHING COLD FRONT THROUGH THE NORTHERN
PLAINS. BEST FORCING STAYS NORTH OF FORECAST AREA...THOUGH A FEW
POST FRONTAL SHOWERS/THUNDERSTORMS POSSIBLE THURSDAY. MODELS
DIVERGE FOR THE WEEKEND...WITH ECMWF BRINGING STRONG SHORTWAVE IN
NORTHWEST FLOW SATURDAY...WHILE GFS MAINTAINS UPPER TROF OVER
WESTERN CONUS AND RIDGING OVER THE PLAINS. TRENDED TOWARDS
ECMWF...WITH COOLER TEMPERATURES AND SMALL POPS.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY)
ISSUED AT 1056 AM MDT SUN AUG 31 2014

SHOWERS AND THUNDERSTORMS WILL BE FOUND ACROSS THE AREA THROUGH
MONDAY MORNING. THE BEST COVERAGE WILL BE LATER THIS AFTERNOON AND
EARLY THIS EVENING. LOCAL MVFR CIGS/IFR VSBYS POSSIBLE WITH THE
STRONGER SHOWERS/STORMS.

&&

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

$$

UPDATE...26
SHORT TERM...13
LONG TERM...7
AVIATION...HELGESON




000
FXUS63 KUNR 311540
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
940 AM MDT SUN AUG 31 2014

.UPDATE...
ISSUED AT 940 AM MDT SUN AUG 31 2014

CURRENT SURFACE ANALYSIS SHOWS LOW PRESSURE OVER SOUTHEAST
ND...WITH COLD FRONT WELL EAST OF OUR FORECAST AREA. UPPER LEVEL
ANALYSIS SHOWS BROAD TROF OVER THE WESTERN CONUS...WITH A SERIES
OF SHORTWAVES WITHIN THE TROF MOVING EAST THROUGH THE ROCKIES AND
PLAINS. LAST NIGHTS WAVE HAS MOVED WELL EAST OF THE AREA...BUT
ANOTHER IS MOVING THROUGH WESTERN NEB INTO PORTIONS OF SOUTHWEST
AND SOUTH CENTRAL SD NOW. YET ANOTHER DISTURBANCE IS NOTED OVER
WESTERN INTO CENTRAL WY...MOVING QUICKLY EASTWARD. KUDX RADAR
SHOWS BULK OF SHOWER ACTIVITY RIGHT NOW IS LOCATED OVER FAR
SOUTHWEST INTO SOUTH CENTRAL SD...WITH ISOLATED SHOWERS ELSEWHERE
TO THE NORTH AND WEST. TEMPS ARE IN THE UPPER 50S AND 60S ACROSS
MOST OF THE AREA WITH LIGHT WEST TO NORTHWEST WINDS.

SHOWERS AND ISOLATED THUNDERSTORMS OVER SOUTHEASTERN PORTIONS OF
THE CWA WILL MOVE EAST THROUGH THE LATE MORNING AND MIDDAY HOURS
AND EVENTUALLY EXIT EAST OF THE AREA. HOWEVER...SHOWERS AND
ISOLATED STORMS WILL CONTINUE TO DEVELOP AND INCREASE IN COVERAGE
FROM WEST TO EAST THROUGH THE MIDDAY AND AFTERNOON HOURS AS THE WY
SYSTEM MOVES EAST OVER THE AREA. THE BEST CHANCES FOR SHOWERS AND
MORE SIGNIFICANT RAINFALL WILL GENERALLY BE OVER THE BLACK HILLS
AREA AND SURROUNDING PLAINS. WITH CLOUD COVER AND RELATIVE LACK OF
WARMING TODAY...THE THREAT FOR SEVERE WEATHER SHOULD BE MINIMAL AT
BEST...WITH A STRONG STORM POSSIBLE OVER FAR SOUTHWEST AND SOUTH
CENTRAL SD THIS AFTERNOON. HIGHS WILL MOSTLY BE IN THE 70S ACROSS
THE SD PLAINS...WITH 60S OVER NORTHEAST WY AND THE BLACK HILLS.
SHOWERS WITH THIS SYSTEM SHOULD GRADUALLY DISSIPATE AND MOVE EAST
OF THE AREA DURING THE EVENING.

HAVE UPDATED TO RAISE POPS OVER MUCH OF THE AREA THROUGH THE DAY
AND TO LOWER HIGH TEMPS A BIT OVER EASTERN AREAS. ALSO MADE
ADJUSTMENTS TO CLOUD COVER AND DEWPOINTS THROUGH THE AFTERNOON.

&&

.SHORT TERM...TODAY THROUGH MONDAY NIGHT
ISSUED AT 300 AM MDT SUN AUG 31 2014

LONGWAVE TROUGH AXIS IS CROSSING MT SOUTH TO WY WITH SEVERAL
EMBEDDED WAVES ROUNDING THE BASE OVER WY. IR SAT/NEIGHBORING RADAR
SHOWS SHRA OVER WY QUICKLY PUSHING EWD. MEANWHILE OVER THE
CWA...SMALL SCALE SUBSIDENCE BEHIND THE WAVE DEPARTING E OF THE CWA
IS LEAVING QUIET WEATHER OVER THE AREA ATTM. THE TROUGH AXIS WILL
CROSS THE CWA TODAY BRINGING SHRA/TSRA TO THE AREA. MLCAPE WILL BE
WEAKER THAN YESTERDAY...500 TO 1000 J/KG TODAY WITH LITTLE TO NO
CAP...STILL ENOUGH FOR SOME STORM DEVELOPMENT. STRONG FORCING W/
THIS WAVE WARRANTS KEEPING AND EXPANDING LIKELY POPS OVER MUCH OF
THE CWA. GIVEN THE SPEED OF THIS SYSTEM...QPF IS EXPECTED TO BE
UNDER A HALF INCH. TEMPERATURES WILL BE A COOL 60S OVER NE WY AND
THE BLACK HILLS...ESPECIALLY AS CLOUDS REMAIN OVER THOSE AREA MUCH
OF THE DAY. THE SD PLAINS ARE EXPECTED TO REACH INTO THE 70S AND
MORNING HEATING COMMENCES BEFORE THE CLOUDS ROLL IN. BREEZY NW
WINDS WILL DEVELOP AS THE SYSTEM MOVES THROUGH WITH REINFORCING
COLD AIR ADVECTION.

SEVERAL UPPER WAVES DIVING DOWN THE BACKSIDE OF THE UPPER TROUGH
OVER THE NRN ROCKIES REGION WILL SLOW DOWN THE EWD PROGRESSION OF
THE OVERALL PATTERN. A SERIES OF WAVES ARE PROGGED TO CROSS THE CWA
MONDAY...WITH A REPEAT OF SHOWERS/STORMS CROSSING THE AREA THROUGH
THE DAY. WITH WEAKER FORCING AND LESS MOISTURE IN THE
ATMOSPHERE...WILL GO WITH CHANCE POPS FOR SHRA ACTIVITY. MLCAPE WILL
BE WEAKER MONDAY THAN TODAY...BUT COULD STILL SEE ISOLATED STORMS.
TEMPERATURES WILL BE IN THE MID 60S TO UPPER 70S. PRECIP WILL END
OVER THE AREA BY LATE MON NIGHT.

&&

.LONG TERM...TUESDAY THROUGH SATURDAY
ISSUED AT 300 AM MDT SUN AUG 31 2014

UPPER TROUGH DIGS ACROSS THE PACIFIC NORTHWEST TUESDAY/WEDNESDAY...
BRINGING FLAT UPPER RIDGE OVER THE NORTHERN PLAINS. THIS WILL
RESULT IN DRY CONDITIONS WITH TEMPERATURES NEAR OR SLIGHTLY ABOVE
AVERAGE. STRONG WAVE LIFTS ACROSS THE NORTHERN ROCKIES LATE
WEDNESDAY/THURSDAY...PUSHING COLD FRONT THROUGH THE NORTHERN
PLAINS. BEST FORCING STAYS NORTH OF FORECAST AREA...THOUGH A FEW
POST FRONTAL SHOWERS/THUNDERSTORMS POSSIBLE THURSDAY. MODELS
DIVERGE FOR THE WEEKEND...WITH ECMWF BRINGING STRONG SHORTWAVE IN
NORTHWEST FLOW SATURDAY...WHILE GFS MAINTAINS UPPER TROF OVER
WESTERN CONUS AND RIDGING OVER THE PLAINS. TRENDED TOWARDS
ECMWF...WITH COOLER TEMPERATURES AND SMALL POPS.

&&

.AVIATION...FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING
ISSUED AT 300 AM MDT SUN AUG 31 2014

SCATTERED SHOWERS AND THUNDERSTORMS WILL BE FOUND ACROSS THE AREA
TODAY. LCL MVFR CIGS/IFR VSBY POSSIBLE WITH THE STRONGER STORMS.


&&

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

$$

UPDATE...26
SHORT TERM...13
LONG TERM...7
AVIATION...7






000
FXUS63 KUNR 311540
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
940 AM MDT SUN AUG 31 2014

.UPDATE...
ISSUED AT 940 AM MDT SUN AUG 31 2014

CURRENT SURFACE ANALYSIS SHOWS LOW PRESSURE OVER SOUTHEAST
ND...WITH COLD FRONT WELL EAST OF OUR FORECAST AREA. UPPER LEVEL
ANALYSIS SHOWS BROAD TROF OVER THE WESTERN CONUS...WITH A SERIES
OF SHORTWAVES WITHIN THE TROF MOVING EAST THROUGH THE ROCKIES AND
PLAINS. LAST NIGHTS WAVE HAS MOVED WELL EAST OF THE AREA...BUT
ANOTHER IS MOVING THROUGH WESTERN NEB INTO PORTIONS OF SOUTHWEST
AND SOUTH CENTRAL SD NOW. YET ANOTHER DISTURBANCE IS NOTED OVER
WESTERN INTO CENTRAL WY...MOVING QUICKLY EASTWARD. KUDX RADAR
SHOWS BULK OF SHOWER ACTIVITY RIGHT NOW IS LOCATED OVER FAR
SOUTHWEST INTO SOUTH CENTRAL SD...WITH ISOLATED SHOWERS ELSEWHERE
TO THE NORTH AND WEST. TEMPS ARE IN THE UPPER 50S AND 60S ACROSS
MOST OF THE AREA WITH LIGHT WEST TO NORTHWEST WINDS.

SHOWERS AND ISOLATED THUNDERSTORMS OVER SOUTHEASTERN PORTIONS OF
THE CWA WILL MOVE EAST THROUGH THE LATE MORNING AND MIDDAY HOURS
AND EVENTUALLY EXIT EAST OF THE AREA. HOWEVER...SHOWERS AND
ISOLATED STORMS WILL CONTINUE TO DEVELOP AND INCREASE IN COVERAGE
FROM WEST TO EAST THROUGH THE MIDDAY AND AFTERNOON HOURS AS THE WY
SYSTEM MOVES EAST OVER THE AREA. THE BEST CHANCES FOR SHOWERS AND
MORE SIGNIFICANT RAINFALL WILL GENERALLY BE OVER THE BLACK HILLS
AREA AND SURROUNDING PLAINS. WITH CLOUD COVER AND RELATIVE LACK OF
WARMING TODAY...THE THREAT FOR SEVERE WEATHER SHOULD BE MINIMAL AT
BEST...WITH A STRONG STORM POSSIBLE OVER FAR SOUTHWEST AND SOUTH
CENTRAL SD THIS AFTERNOON. HIGHS WILL MOSTLY BE IN THE 70S ACROSS
THE SD PLAINS...WITH 60S OVER NORTHEAST WY AND THE BLACK HILLS.
SHOWERS WITH THIS SYSTEM SHOULD GRADUALLY DISSIPATE AND MOVE EAST
OF THE AREA DURING THE EVENING.

HAVE UPDATED TO RAISE POPS OVER MUCH OF THE AREA THROUGH THE DAY
AND TO LOWER HIGH TEMPS A BIT OVER EASTERN AREAS. ALSO MADE
ADJUSTMENTS TO CLOUD COVER AND DEWPOINTS THROUGH THE AFTERNOON.

&&

.SHORT TERM...TODAY THROUGH MONDAY NIGHT
ISSUED AT 300 AM MDT SUN AUG 31 2014

LONGWAVE TROUGH AXIS IS CROSSING MT SOUTH TO WY WITH SEVERAL
EMBEDDED WAVES ROUNDING THE BASE OVER WY. IR SAT/NEIGHBORING RADAR
SHOWS SHRA OVER WY QUICKLY PUSHING EWD. MEANWHILE OVER THE
CWA...SMALL SCALE SUBSIDENCE BEHIND THE WAVE DEPARTING E OF THE CWA
IS LEAVING QUIET WEATHER OVER THE AREA ATTM. THE TROUGH AXIS WILL
CROSS THE CWA TODAY BRINGING SHRA/TSRA TO THE AREA. MLCAPE WILL BE
WEAKER THAN YESTERDAY...500 TO 1000 J/KG TODAY WITH LITTLE TO NO
CAP...STILL ENOUGH FOR SOME STORM DEVELOPMENT. STRONG FORCING W/
THIS WAVE WARRANTS KEEPING AND EXPANDING LIKELY POPS OVER MUCH OF
THE CWA. GIVEN THE SPEED OF THIS SYSTEM...QPF IS EXPECTED TO BE
UNDER A HALF INCH. TEMPERATURES WILL BE A COOL 60S OVER NE WY AND
THE BLACK HILLS...ESPECIALLY AS CLOUDS REMAIN OVER THOSE AREA MUCH
OF THE DAY. THE SD PLAINS ARE EXPECTED TO REACH INTO THE 70S AND
MORNING HEATING COMMENCES BEFORE THE CLOUDS ROLL IN. BREEZY NW
WINDS WILL DEVELOP AS THE SYSTEM MOVES THROUGH WITH REINFORCING
COLD AIR ADVECTION.

SEVERAL UPPER WAVES DIVING DOWN THE BACKSIDE OF THE UPPER TROUGH
OVER THE NRN ROCKIES REGION WILL SLOW DOWN THE EWD PROGRESSION OF
THE OVERALL PATTERN. A SERIES OF WAVES ARE PROGGED TO CROSS THE CWA
MONDAY...WITH A REPEAT OF SHOWERS/STORMS CROSSING THE AREA THROUGH
THE DAY. WITH WEAKER FORCING AND LESS MOISTURE IN THE
ATMOSPHERE...WILL GO WITH CHANCE POPS FOR SHRA ACTIVITY. MLCAPE WILL
BE WEAKER MONDAY THAN TODAY...BUT COULD STILL SEE ISOLATED STORMS.
TEMPERATURES WILL BE IN THE MID 60S TO UPPER 70S. PRECIP WILL END
OVER THE AREA BY LATE MON NIGHT.

&&

.LONG TERM...TUESDAY THROUGH SATURDAY
ISSUED AT 300 AM MDT SUN AUG 31 2014

UPPER TROUGH DIGS ACROSS THE PACIFIC NORTHWEST TUESDAY/WEDNESDAY...
BRINGING FLAT UPPER RIDGE OVER THE NORTHERN PLAINS. THIS WILL
RESULT IN DRY CONDITIONS WITH TEMPERATURES NEAR OR SLIGHTLY ABOVE
AVERAGE. STRONG WAVE LIFTS ACROSS THE NORTHERN ROCKIES LATE
WEDNESDAY/THURSDAY...PUSHING COLD FRONT THROUGH THE NORTHERN
PLAINS. BEST FORCING STAYS NORTH OF FORECAST AREA...THOUGH A FEW
POST FRONTAL SHOWERS/THUNDERSTORMS POSSIBLE THURSDAY. MODELS
DIVERGE FOR THE WEEKEND...WITH ECMWF BRINGING STRONG SHORTWAVE IN
NORTHWEST FLOW SATURDAY...WHILE GFS MAINTAINS UPPER TROF OVER
WESTERN CONUS AND RIDGING OVER THE PLAINS. TRENDED TOWARDS
ECMWF...WITH COOLER TEMPERATURES AND SMALL POPS.

&&

.AVIATION...FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING
ISSUED AT 300 AM MDT SUN AUG 31 2014

SCATTERED SHOWERS AND THUNDERSTORMS WILL BE FOUND ACROSS THE AREA
TODAY. LCL MVFR CIGS/IFR VSBY POSSIBLE WITH THE STRONGER STORMS.


&&

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

$$

UPDATE...26
SHORT TERM...13
LONG TERM...7
AVIATION...7







000
FXUS65 KCYS 311150
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
550 AM MDT SUN AUG 31 2014

.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 345 AM MDT SUN AUG 31 2014

CURRENT KCYS RADAR LOOP SHOWS AN AREA OF RAIN SHOWERS AND EMBEDDED
THUNDERSTORMS QUICKLY MOVING EASTWARD ACROSS THE AREA EARLY THIS
MORNING. THIS ACTIVITY IS IN ADVANCE OF AN UPPER LEVEL TROUGH AXIS
MOVING INTO WESTERN WYOMING. 250 MB JET STREAM WINDS WILL CONTINUE
TO INCREASE THIS MORNING OVER 100 KNOTS AS THE SURFACE COLD FRONT
HAS JUST STARTED TO ACCELERATE SOUTHEAST ACROSS THE FORECAST AREA.
EXPECT A COOLER THAN AVERAGE DAY TODAY BEHIND THIS COLD FRONT AS
THE TROUGH AXIS MOVES ACROSS SOUTHEAST WYOMING...RESULTING IN
SURFACE TEMPERATURES IN THE UPPER 60S TO MID 70S ACROSS MOST OF
THE FORECAST AREA. IT WILL BE A LITTLE WARMER FURTHER SOUTH AND
EAST ACROSS THE SOUTHERN NEBRASKA PANHANDLE SINCE THE FRONT WILL
STALL LATER TODAY. SHOWERS AND ISOLATED THUNDERSTORMS ARE EXPECTED
THROUGH TODAY. THE GFS CONTINUES TO BE ON THE DRY SIDE EVEN THOUGH
THE RADAR IMAGERY THIS MORNING HAS BEEN ACTIVE. WITH A STRONG JET
OVERHEAD...BELIEVE MODELS CONTINUE TO DOWNPLAY THE CHANCES FOR
WIDESPREAD SHOWERS TODAY. KEPT POP BETWEEN 40 TO 60 PERCENT FOR
SCATTERED SHOWERS AND ISOLATED THUNDER INTO THIS EVENING. WINDY
CONDITIONS ARE EXPECTED THIS AFTERNOON AFTER FROPA...WITH GUSTS UP
TO 45 MPH POSSIBLE WEST OF THE LARAMIE RANGE. WINDS WILL STRUGGLE
TO REACH 30 MPH OVER THE NEBRASKA PANHANDLE THIS AFTERNOON. SHOWER
ACTIVITY WILL QUICKLY COME TO AND END EARLY THIS EVENING AS DRIER
AND MORE STABLE AIR MOVE INTO THE REGION. SKIES WILL QUICKLY CLEAR
TONIGHT WITH CHILLY OVERNIGHT LOWS IN THE 30S TO MID 40S EXPECTED.

ANOTHER COOL DAY EXPECTED ON MONDAY WITH HIGHS STRUGGLING TO
REACH THE LOW TO MID 70S ACROSS MOST OF THE AREA. MODELS SHOW A
SECONDARY SHORTWAVE QUICKLY PUSHING ACROSS THE AREA...RESULTING IN
SOME RAIN SHOWER ACTIVITY AND MAYBE A FEW LIGHTNING STRIKES.

UPPER LEVEL FLOW BECOMES MORE ZONAL FOR TUESDAY WITH INCREASING
TEMPERATURES INTO THE UPPER 70S TO MID 80S ACROSS THE AREA. DRIER
AIR WILL PUSH INTO THE REGION WITH PW/S LOWERING BELOW ONE HALF
INCH DURING THE DAY.

.LONG TERM...(TUESDAY NIGHT THROUGH SATURDAY)
ISSUED AT 300 AM MDT SUN AUG 31 2014

THE LONG TERM FORECAST WILL START OFF DRY AND BREEZY WEDNESDAY UNDER
ZONAL FLOW ACROSS THE CONUS. DOWNSLOPE FLOW WILL PUSH TEMPERATURES
INTO THE 80S ACROSS SOUTHEAST WYOMING AND 90S INTO THE PANHANDLE. BY
THURSDAY AN UPPER LEVEL TROUGH WILL DIG OVER THE PACIFIC NORTHWEST
WITH SOUTHWEST FLOW KICKING IN ACROSS THE CENTRAL AND NORTHERN
ROCKIES. WILL START TO SEE INCREASING CHANCES FOR SHOWERS AND
THUNDERSTORMS LATE THURSDAY AND THEN INTO THURSDAY NIGHT. THURSDAY
SHOULD BE A BIT COOLER AS MID AND UPPER LEVEL CLOUD COVER LIMITS
DEEPER MIXING.

FORECAST MUCH MORE TRICKY FRIDAY AND SATURDAY AS MODEL SOLUTIONS
DIVERGE. GFS DEVELOPS A SLOW MOVING CLOSE LOW OVER THE WESTERN CONUS
WITH RELATIVELY DRY SOUTHWEST FLOW FOR THE FORECAST AREA. THE ECMWF
ON THE OTHER HAND SHOWS A MORE PROGRESSIVE WAVE SUPPRESSING THE RIDGE
OVER THE ROCKIES FRIDAY AND THEN DEVELOPING NORTHWEST FLOW BY
SATURDAY. IN OTHER WORDS THE ECMWF IS NOT ONLY COOLER BUT WOULD ALSO
SUGGESTS INCREASED PRECIPITATION CHANCES. NOT COMPLETELY CONFIDENT IN
EITHER MODEL BUT LEANING TOWARD THE ECMWF AS OVERALL WEATHER PATTERN
PERSISTENCE GOING ALL THE WAY BACK TO LAST WINTER FAVORS NORTHWEST
FLOW.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 542 AM MDT SUN AUG 31 2014

SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS WILL OCCUR ACROSS
SOUTHEAST WYOMING AND THE NEBRASKA PANHANDLE TODAY. GUSTY WINDS
WILL OCCUR WITH SOME SHOWERS AND THUNDERSTORMS BUT SEVERE
THUNDERSTORMS ARE GENERALLY NOT EXPECTED. OUTSIDE OF THE
THUNDERSTORM ACTIVITY GUSTS TO 40 MPH WILL OCCUR ALONG AND WEST
OF THE LARAMIE RANGE MAINLY THIS AFTERNOON. SHOWERS AND
THUNDERSTORMS WILL MOVE EAST OF THE AREA AND/OR DIE OFF BY EARLY
THIS EVENING AS A SHORTWAVE MOVES INTO THE NORTHERN PLAINS.


&&

.FIRE WEATHER...
ISSUED AT 244 AM MDT SUN AUG 31 2014

NO FIRE WEATHER CONCERNS THROUGH MONDAY...BUT THEN CONCERN OF NEAR
CRITICAL CONDITIONS INCREASE FOR TUESDAY AND WEDNESDAY. A STRONG
WEATHER DISTURBANCE AND ASSOCIATED COLD FRONT WILL MOVE ACROSS
THE AREA EARLY THIS MORNING. SHOWERS AND TSTORMS WILL CONTINUE
ACROSS SOUTHEAST WYOMING AND WESTERN NEBRASKA TODAY WITH GUSTY
WEST TO SOUTHWEST WINDS. DRIER CONDITIONS WILL DEVELOP BY MIDDLE
OF NEXT WEEK WHILE GUSTY WEST WINDS CONTINUE IN AREAS ALONG AND
WEST OF THE LARAMIE RANGE.

&&

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

$$

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






000
FXUS65 KCYS 310944
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
344 AM MDT SUN AUG 31 2014

.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 345 AM MDT SUN AUG 31 2014

CURRENT KCYS RADAR LOOP SHOWS AN AREA OF RAIN SHOWERS AND EMBEDDED
THUNDERSTORMS QUICKLY MOVING EASTWARD ACROSS THE AREA EARLY THIS
MORNING. THIS ACTIVITY IS IN ADVANCE OF AN UPPER LEVEL TROUGH AXIS
MOVING INTO WESTERN WYOMING. 250 MB JET STREAM WINDS WILL CONTINUE
TO INCREASE THIS MORNING OVER 100 KNOTS AS THE SURFACE COLD FRONT
HAS JUST STARTED TO ACCELERATE SOUTHEAST ACROSS THE FORECAST AREA.
EXPECT A COOLER THAN AVERAGE DAY TODAY BEHIND THIS COLD FRONT AS
THE TROUGH AXIS MOVES ACROSS SOUTHEAST WYOMING...RESULTING IN
SURFACE TEMPERATURES IN THE UPPER 60S TO MID 70S ACROSS MOST OF
THE FORECAST AREA. IT WILL BE A LITTLE WARMER FURTHER SOUTH AND
EAST ACROSS THE SOUTHERN NEBRASKA PANHANDLE SINCE THE FRONT WILL
STALL LATER TODAY. SHOWERS AND ISOLATED THUNDERSTORMS ARE EXPECTED
THROUGH TODAY. THE GFS CONTINUES TO BE ON THE DRY SIDE EVEN THOUGH
THE RADAR IMAGERY THIS MORNING HAS BEEN ACTIVE. WITH A STRONG JET
OVERHEAD...BELIEVE MODELS CONTINUE TO DOWNPLAY THE CHANCES FOR
WIDESPREAD SHOWERS TODAY. KEPT POP BETWEEN 40 TO 60 PERCENT FOR
SCATTERED SHOWERS AND ISOLATED THUNDER INTO THIS EVENING. WINDY
CONDITIONS ARE EXPECTED THIS AFTERNOON AFTER FROPA...WITH GUSTS UP
TO 45 MPH POSSIBLE WEST OF THE LARAMIE RANGE. WINDS WILL STRUGGLE
TO REACH 30 MPH OVER THE NEBRASKA PANHANDLE THIS AFTERNOON. SHOWER
ACTIVITY WILL QUICKLY COME TO AND END EARLY THIS EVENING AS DRIER
AND MORE STABLE AIR MOVE INTO THE REGION. SKIES WILL QUICKLY CLEAR
TONIGHT WITH CHILLY OVERNIGHT LOWS IN THE 30S TO MID 40S EXPECTED.

ANOTHER COOL DAY EXPECTED ON MONDAY WITH HIGHS STRUGGLING TO
REACH THE LOW TO MID 70S ACROSS MOST OF THE AREA. MODELS SHOW A
SECONDARY SHORTWAVE QUICKLY PUSHING ACROSS THE AREA...RESULTING IN
SOME RAIN SHOWER ACTIVITY AND MAYBE A FEW LIGHTNING STRIKES.

UPPER LEVEL FLOW BECOMES MORE ZONAL FOR TUESDAY WITH INCREASING
TEMPERATURES INTO THE UPPER 70S TO MID 80S ACROSS THE AREA. DRIER
AIR WILL PUSH INTO THE REGION WITH PW/S LOWERING BELOW ONE HALF
INCH DURING THE DAY.


.LONG TERM...(TUESDAY NIGHT THROUGH SATURDAY)
ISSUED AT 300 AM MDT SUN AUG 31 2014

THE LONG TERM FORECAST WILL START OFF DRY AND BREEZY WEDNESDAY UNDER
ZONAL FLOW ACROSS THE CONUS. DOWNSLOPE FLOW WILL PUSH TEMPERATURES
INTO THE 80S ACROSS SOUTHEAST WYOMING AND 90S INTO THE PANHANDLE. BY
THURSDAY AN UPPER LEVEL TROUGH WILL DIG OVER THE PACIFIC NORTHWEST
WITH SOUTHWEST FLOW KICKING IN ACROSS THE CENTRAL AND NORTHERN
ROCKIES. WILL START TO SEE INCREASING CHANCES FOR SHOWERS AND
THUNDERSTORMS LATE THURSDAY AND THEN INTO THURSDAY NIGHT. THURSDAY
SHOULD BE A BIT COOLER AS MID AND UPPER LEVEL CLOUD COVER LIMITS
DEEPER MIXING.

FORECAST MUCH MORE TRICKY FRIDAY AND SATURDAY AS MODEL SOLUTIONS
DIVERGE. GFS DEVELOPS A SLOW MOVING CLOSE LOW OVER THE WESTERN CONUS
WITH RELATIVELY DRY SOUTHWEST FLOW FOR THE FORECAST AREA. THE ECMWF
ON THE OTHER HAND SHOWS A MORE PROGRESSIVE WAVE SUPPRESSING THE RIDGE
OVER THE ROCKIES FRIDAY AND THEN DEVELOPING NORTHWEST FLOW BY
SATURDAY. IN OTHER WORDS THE ECMWF IS NOT ONLY COOLER BUT WOULD ALSO
SUGGESTS INCREASED PRECIPITATION CHANCES. NOT COMPLETELY CONFIDENT IN
EITHER MODEL BUT LEANING TOWARD THE ECMWF AS OVERALL WEATHER PATTERN
PERSISTENCE GOING ALL THE WAY BACK TO LAST WINTER FAVORS NORTHWEST
FLOW.


&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY EVENING)
ISSUED AT 1025 PM MDT SAT AUG 30 2014

COLD FRONT CONTINUES TO SLOWLY MOVE INTO THE AREA LATE THIS
EVENING. STILL KICKING OFF SOME THUNDERSTORMS OVER THE MOUNTAINS
TO THE WEST...BUT ELSEWHERE...RADAR SHOWING CONVECTION COMING TO
AN END. VFR CONDITIONS EXPECTED AT ALL TAF SITES OVERNIGHT. RETURN
OF GUSTY WINDS AND ISOLATED THUNDERSTORMS FOR SUNDAY AFTERNOON.


&&

.FIRE WEATHER...
ISSUED AT 244 AM MDT SUN AUG 31 2014

NO FIRE WEATHER CONCERNS THROUGH MONDAY...BUT THEN CONCERN OF NEAR
CRITICAL CONDITIONS INCREASE FOR TUESDAY AND WEDNESDAY. A STRONG
WEATHER DISTURBANCE AND ASSOCIATED COLD FRONT WILL MOVE ACROSS
THE AREA EARLY THIS MORNING. SHOWERS AND TSTORMS WILL CONTINUE
ACROSS SOUTHEAST WYOMING AND WESTERN NEBRASKA TODAY WITH GUSTY
WEST TO SOUTHWEST WINDS. DRIER CONDITIONS WILL DEVELOP BY MIDDLE
OF NEXT WEEK WHILE GUSTY WEST WINDS CONTINUE IN AREAS ALONG AND
WEST OF THE LARAMIE RANGE.

&&

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

$$

SHORT TERM...TJT
LONG TERM...SML
AVIATION...CLAYCOMB
FIRE WEATHER...TJT







000
FXUS65 KCYS 310944
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
344 AM MDT SUN AUG 31 2014

.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 345 AM MDT SUN AUG 31 2014

CURRENT KCYS RADAR LOOP SHOWS AN AREA OF RAIN SHOWERS AND EMBEDDED
THUNDERSTORMS QUICKLY MOVING EASTWARD ACROSS THE AREA EARLY THIS
MORNING. THIS ACTIVITY IS IN ADVANCE OF AN UPPER LEVEL TROUGH AXIS
MOVING INTO WESTERN WYOMING. 250 MB JET STREAM WINDS WILL CONTINUE
TO INCREASE THIS MORNING OVER 100 KNOTS AS THE SURFACE COLD FRONT
HAS JUST STARTED TO ACCELERATE SOUTHEAST ACROSS THE FORECAST AREA.
EXPECT A COOLER THAN AVERAGE DAY TODAY BEHIND THIS COLD FRONT AS
THE TROUGH AXIS MOVES ACROSS SOUTHEAST WYOMING...RESULTING IN
SURFACE TEMPERATURES IN THE UPPER 60S TO MID 70S ACROSS MOST OF
THE FORECAST AREA. IT WILL BE A LITTLE WARMER FURTHER SOUTH AND
EAST ACROSS THE SOUTHERN NEBRASKA PANHANDLE SINCE THE FRONT WILL
STALL LATER TODAY. SHOWERS AND ISOLATED THUNDERSTORMS ARE EXPECTED
THROUGH TODAY. THE GFS CONTINUES TO BE ON THE DRY SIDE EVEN THOUGH
THE RADAR IMAGERY THIS MORNING HAS BEEN ACTIVE. WITH A STRONG JET
OVERHEAD...BELIEVE MODELS CONTINUE TO DOWNPLAY THE CHANCES FOR
WIDESPREAD SHOWERS TODAY. KEPT POP BETWEEN 40 TO 60 PERCENT FOR
SCATTERED SHOWERS AND ISOLATED THUNDER INTO THIS EVENING. WINDY
CONDITIONS ARE EXPECTED THIS AFTERNOON AFTER FROPA...WITH GUSTS UP
TO 45 MPH POSSIBLE WEST OF THE LARAMIE RANGE. WINDS WILL STRUGGLE
TO REACH 30 MPH OVER THE NEBRASKA PANHANDLE THIS AFTERNOON. SHOWER
ACTIVITY WILL QUICKLY COME TO AND END EARLY THIS EVENING AS DRIER
AND MORE STABLE AIR MOVE INTO THE REGION. SKIES WILL QUICKLY CLEAR
TONIGHT WITH CHILLY OVERNIGHT LOWS IN THE 30S TO MID 40S EXPECTED.

ANOTHER COOL DAY EXPECTED ON MONDAY WITH HIGHS STRUGGLING TO
REACH THE LOW TO MID 70S ACROSS MOST OF THE AREA. MODELS SHOW A
SECONDARY SHORTWAVE QUICKLY PUSHING ACROSS THE AREA...RESULTING IN
SOME RAIN SHOWER ACTIVITY AND MAYBE A FEW LIGHTNING STRIKES.

UPPER LEVEL FLOW BECOMES MORE ZONAL FOR TUESDAY WITH INCREASING
TEMPERATURES INTO THE UPPER 70S TO MID 80S ACROSS THE AREA. DRIER
AIR WILL PUSH INTO THE REGION WITH PW/S LOWERING BELOW ONE HALF
INCH DURING THE DAY.


.LONG TERM...(TUESDAY NIGHT THROUGH SATURDAY)
ISSUED AT 300 AM MDT SUN AUG 31 2014

THE LONG TERM FORECAST WILL START OFF DRY AND BREEZY WEDNESDAY UNDER
ZONAL FLOW ACROSS THE CONUS. DOWNSLOPE FLOW WILL PUSH TEMPERATURES
INTO THE 80S ACROSS SOUTHEAST WYOMING AND 90S INTO THE PANHANDLE. BY
THURSDAY AN UPPER LEVEL TROUGH WILL DIG OVER THE PACIFIC NORTHWEST
WITH SOUTHWEST FLOW KICKING IN ACROSS THE CENTRAL AND NORTHERN
ROCKIES. WILL START TO SEE INCREASING CHANCES FOR SHOWERS AND
THUNDERSTORMS LATE THURSDAY AND THEN INTO THURSDAY NIGHT. THURSDAY
SHOULD BE A BIT COOLER AS MID AND UPPER LEVEL CLOUD COVER LIMITS
DEEPER MIXING.

FORECAST MUCH MORE TRICKY FRIDAY AND SATURDAY AS MODEL SOLUTIONS
DIVERGE. GFS DEVELOPS A SLOW MOVING CLOSE LOW OVER THE WESTERN CONUS
WITH RELATIVELY DRY SOUTHWEST FLOW FOR THE FORECAST AREA. THE ECMWF
ON THE OTHER HAND SHOWS A MORE PROGRESSIVE WAVE SUPPRESSING THE RIDGE
OVER THE ROCKIES FRIDAY AND THEN DEVELOPING NORTHWEST FLOW BY
SATURDAY. IN OTHER WORDS THE ECMWF IS NOT ONLY COOLER BUT WOULD ALSO
SUGGESTS INCREASED PRECIPITATION CHANCES. NOT COMPLETELY CONFIDENT IN
EITHER MODEL BUT LEANING TOWARD THE ECMWF AS OVERALL WEATHER PATTERN
PERSISTENCE GOING ALL THE WAY BACK TO LAST WINTER FAVORS NORTHWEST
FLOW.


&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY EVENING)
ISSUED AT 1025 PM MDT SAT AUG 30 2014

COLD FRONT CONTINUES TO SLOWLY MOVE INTO THE AREA LATE THIS
EVENING. STILL KICKING OFF SOME THUNDERSTORMS OVER THE MOUNTAINS
TO THE WEST...BUT ELSEWHERE...RADAR SHOWING CONVECTION COMING TO
AN END. VFR CONDITIONS EXPECTED AT ALL TAF SITES OVERNIGHT. RETURN
OF GUSTY WINDS AND ISOLATED THUNDERSTORMS FOR SUNDAY AFTERNOON.


&&

.FIRE WEATHER...
ISSUED AT 244 AM MDT SUN AUG 31 2014

NO FIRE WEATHER CONCERNS THROUGH MONDAY...BUT THEN CONCERN OF NEAR
CRITICAL CONDITIONS INCREASE FOR TUESDAY AND WEDNESDAY. A STRONG
WEATHER DISTURBANCE AND ASSOCIATED COLD FRONT WILL MOVE ACROSS
THE AREA EARLY THIS MORNING. SHOWERS AND TSTORMS WILL CONTINUE
ACROSS SOUTHEAST WYOMING AND WESTERN NEBRASKA TODAY WITH GUSTY
WEST TO SOUTHWEST WINDS. DRIER CONDITIONS WILL DEVELOP BY MIDDLE
OF NEXT WEEK WHILE GUSTY WEST WINDS CONTINUE IN AREAS ALONG AND
WEST OF THE LARAMIE RANGE.

&&

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

$$

SHORT TERM...TJT
LONG TERM...SML
AVIATION...CLAYCOMB
FIRE WEATHER...TJT







000
FXUS65 KCYS 310944
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
344 AM MDT SUN AUG 31 2014

.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 345 AM MDT SUN AUG 31 2014

CURRENT KCYS RADAR LOOP SHOWS AN AREA OF RAIN SHOWERS AND EMBEDDED
THUNDERSTORMS QUICKLY MOVING EASTWARD ACROSS THE AREA EARLY THIS
MORNING. THIS ACTIVITY IS IN ADVANCE OF AN UPPER LEVEL TROUGH AXIS
MOVING INTO WESTERN WYOMING. 250 MB JET STREAM WINDS WILL CONTINUE
TO INCREASE THIS MORNING OVER 100 KNOTS AS THE SURFACE COLD FRONT
HAS JUST STARTED TO ACCELERATE SOUTHEAST ACROSS THE FORECAST AREA.
EXPECT A COOLER THAN AVERAGE DAY TODAY BEHIND THIS COLD FRONT AS
THE TROUGH AXIS MOVES ACROSS SOUTHEAST WYOMING...RESULTING IN
SURFACE TEMPERATURES IN THE UPPER 60S TO MID 70S ACROSS MOST OF
THE FORECAST AREA. IT WILL BE A LITTLE WARMER FURTHER SOUTH AND
EAST ACROSS THE SOUTHERN NEBRASKA PANHANDLE SINCE THE FRONT WILL
STALL LATER TODAY. SHOWERS AND ISOLATED THUNDERSTORMS ARE EXPECTED
THROUGH TODAY. THE GFS CONTINUES TO BE ON THE DRY SIDE EVEN THOUGH
THE RADAR IMAGERY THIS MORNING HAS BEEN ACTIVE. WITH A STRONG JET
OVERHEAD...BELIEVE MODELS CONTINUE TO DOWNPLAY THE CHANCES FOR
WIDESPREAD SHOWERS TODAY. KEPT POP BETWEEN 40 TO 60 PERCENT FOR
SCATTERED SHOWERS AND ISOLATED THUNDER INTO THIS EVENING. WINDY
CONDITIONS ARE EXPECTED THIS AFTERNOON AFTER FROPA...WITH GUSTS UP
TO 45 MPH POSSIBLE WEST OF THE LARAMIE RANGE. WINDS WILL STRUGGLE
TO REACH 30 MPH OVER THE NEBRASKA PANHANDLE THIS AFTERNOON. SHOWER
ACTIVITY WILL QUICKLY COME TO AND END EARLY THIS EVENING AS DRIER
AND MORE STABLE AIR MOVE INTO THE REGION. SKIES WILL QUICKLY CLEAR
TONIGHT WITH CHILLY OVERNIGHT LOWS IN THE 30S TO MID 40S EXPECTED.

ANOTHER COOL DAY EXPECTED ON MONDAY WITH HIGHS STRUGGLING TO
REACH THE LOW TO MID 70S ACROSS MOST OF THE AREA. MODELS SHOW A
SECONDARY SHORTWAVE QUICKLY PUSHING ACROSS THE AREA...RESULTING IN
SOME RAIN SHOWER ACTIVITY AND MAYBE A FEW LIGHTNING STRIKES.

UPPER LEVEL FLOW BECOMES MORE ZONAL FOR TUESDAY WITH INCREASING
TEMPERATURES INTO THE UPPER 70S TO MID 80S ACROSS THE AREA. DRIER
AIR WILL PUSH INTO THE REGION WITH PW/S LOWERING BELOW ONE HALF
INCH DURING THE DAY.


.LONG TERM...(TUESDAY NIGHT THROUGH SATURDAY)
ISSUED AT 300 AM MDT SUN AUG 31 2014

THE LONG TERM FORECAST WILL START OFF DRY AND BREEZY WEDNESDAY UNDER
ZONAL FLOW ACROSS THE CONUS. DOWNSLOPE FLOW WILL PUSH TEMPERATURES
INTO THE 80S ACROSS SOUTHEAST WYOMING AND 90S INTO THE PANHANDLE. BY
THURSDAY AN UPPER LEVEL TROUGH WILL DIG OVER THE PACIFIC NORTHWEST
WITH SOUTHWEST FLOW KICKING IN ACROSS THE CENTRAL AND NORTHERN
ROCKIES. WILL START TO SEE INCREASING CHANCES FOR SHOWERS AND
THUNDERSTORMS LATE THURSDAY AND THEN INTO THURSDAY NIGHT. THURSDAY
SHOULD BE A BIT COOLER AS MID AND UPPER LEVEL CLOUD COVER LIMITS
DEEPER MIXING.

FORECAST MUCH MORE TRICKY FRIDAY AND SATURDAY AS MODEL SOLUTIONS
DIVERGE. GFS DEVELOPS A SLOW MOVING CLOSE LOW OVER THE WESTERN CONUS
WITH RELATIVELY DRY SOUTHWEST FLOW FOR THE FORECAST AREA. THE ECMWF
ON THE OTHER HAND SHOWS A MORE PROGRESSIVE WAVE SUPPRESSING THE RIDGE
OVER THE ROCKIES FRIDAY AND THEN DEVELOPING NORTHWEST FLOW BY
SATURDAY. IN OTHER WORDS THE ECMWF IS NOT ONLY COOLER BUT WOULD ALSO
SUGGESTS INCREASED PRECIPITATION CHANCES. NOT COMPLETELY CONFIDENT IN
EITHER MODEL BUT LEANING TOWARD THE ECMWF AS OVERALL WEATHER PATTERN
PERSISTENCE GOING ALL THE WAY BACK TO LAST WINTER FAVORS NORTHWEST
FLOW.


&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY EVENING)
ISSUED AT 1025 PM MDT SAT AUG 30 2014

COLD FRONT CONTINUES TO SLOWLY MOVE INTO THE AREA LATE THIS
EVENING. STILL KICKING OFF SOME THUNDERSTORMS OVER THE MOUNTAINS
TO THE WEST...BUT ELSEWHERE...RADAR SHOWING CONVECTION COMING TO
AN END. VFR CONDITIONS EXPECTED AT ALL TAF SITES OVERNIGHT. RETURN
OF GUSTY WINDS AND ISOLATED THUNDERSTORMS FOR SUNDAY AFTERNOON.


&&

.FIRE WEATHER...
ISSUED AT 244 AM MDT SUN AUG 31 2014

NO FIRE WEATHER CONCERNS THROUGH MONDAY...BUT THEN CONCERN OF NEAR
CRITICAL CONDITIONS INCREASE FOR TUESDAY AND WEDNESDAY. A STRONG
WEATHER DISTURBANCE AND ASSOCIATED COLD FRONT WILL MOVE ACROSS
THE AREA EARLY THIS MORNING. SHOWERS AND TSTORMS WILL CONTINUE
ACROSS SOUTHEAST WYOMING AND WESTERN NEBRASKA TODAY WITH GUSTY
WEST TO SOUTHWEST WINDS. DRIER CONDITIONS WILL DEVELOP BY MIDDLE
OF NEXT WEEK WHILE GUSTY WEST WINDS CONTINUE IN AREAS ALONG AND
WEST OF THE LARAMIE RANGE.

&&

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

$$

SHORT TERM...TJT
LONG TERM...SML
AVIATION...CLAYCOMB
FIRE WEATHER...TJT







000
FXUS65 KCYS 310944
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
344 AM MDT SUN AUG 31 2014

.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 345 AM MDT SUN AUG 31 2014

CURRENT KCYS RADAR LOOP SHOWS AN AREA OF RAIN SHOWERS AND EMBEDDED
THUNDERSTORMS QUICKLY MOVING EASTWARD ACROSS THE AREA EARLY THIS
MORNING. THIS ACTIVITY IS IN ADVANCE OF AN UPPER LEVEL TROUGH AXIS
MOVING INTO WESTERN WYOMING. 250 MB JET STREAM WINDS WILL CONTINUE
TO INCREASE THIS MORNING OVER 100 KNOTS AS THE SURFACE COLD FRONT
HAS JUST STARTED TO ACCELERATE SOUTHEAST ACROSS THE FORECAST AREA.
EXPECT A COOLER THAN AVERAGE DAY TODAY BEHIND THIS COLD FRONT AS
THE TROUGH AXIS MOVES ACROSS SOUTHEAST WYOMING...RESULTING IN
SURFACE TEMPERATURES IN THE UPPER 60S TO MID 70S ACROSS MOST OF
THE FORECAST AREA. IT WILL BE A LITTLE WARMER FURTHER SOUTH AND
EAST ACROSS THE SOUTHERN NEBRASKA PANHANDLE SINCE THE FRONT WILL
STALL LATER TODAY. SHOWERS AND ISOLATED THUNDERSTORMS ARE EXPECTED
THROUGH TODAY. THE GFS CONTINUES TO BE ON THE DRY SIDE EVEN THOUGH
THE RADAR IMAGERY THIS MORNING HAS BEEN ACTIVE. WITH A STRONG JET
OVERHEAD...BELIEVE MODELS CONTINUE TO DOWNPLAY THE CHANCES FOR
WIDESPREAD SHOWERS TODAY. KEPT POP BETWEEN 40 TO 60 PERCENT FOR
SCATTERED SHOWERS AND ISOLATED THUNDER INTO THIS EVENING. WINDY
CONDITIONS ARE EXPECTED THIS AFTERNOON AFTER FROPA...WITH GUSTS UP
TO 45 MPH POSSIBLE WEST OF THE LARAMIE RANGE. WINDS WILL STRUGGLE
TO REACH 30 MPH OVER THE NEBRASKA PANHANDLE THIS AFTERNOON. SHOWER
ACTIVITY WILL QUICKLY COME TO AND END EARLY THIS EVENING AS DRIER
AND MORE STABLE AIR MOVE INTO THE REGION. SKIES WILL QUICKLY CLEAR
TONIGHT WITH CHILLY OVERNIGHT LOWS IN THE 30S TO MID 40S EXPECTED.

ANOTHER COOL DAY EXPECTED ON MONDAY WITH HIGHS STRUGGLING TO
REACH THE LOW TO MID 70S ACROSS MOST OF THE AREA. MODELS SHOW A
SECONDARY SHORTWAVE QUICKLY PUSHING ACROSS THE AREA...RESULTING IN
SOME RAIN SHOWER ACTIVITY AND MAYBE A FEW LIGHTNING STRIKES.

UPPER LEVEL FLOW BECOMES MORE ZONAL FOR TUESDAY WITH INCREASING
TEMPERATURES INTO THE UPPER 70S TO MID 80S ACROSS THE AREA. DRIER
AIR WILL PUSH INTO THE REGION WITH PW/S LOWERING BELOW ONE HALF
INCH DURING THE DAY.


.LONG TERM...(TUESDAY NIGHT THROUGH SATURDAY)
ISSUED AT 300 AM MDT SUN AUG 31 2014

THE LONG TERM FORECAST WILL START OFF DRY AND BREEZY WEDNESDAY UNDER
ZONAL FLOW ACROSS THE CONUS. DOWNSLOPE FLOW WILL PUSH TEMPERATURES
INTO THE 80S ACROSS SOUTHEAST WYOMING AND 90S INTO THE PANHANDLE. BY
THURSDAY AN UPPER LEVEL TROUGH WILL DIG OVER THE PACIFIC NORTHWEST
WITH SOUTHWEST FLOW KICKING IN ACROSS THE CENTRAL AND NORTHERN
ROCKIES. WILL START TO SEE INCREASING CHANCES FOR SHOWERS AND
THUNDERSTORMS LATE THURSDAY AND THEN INTO THURSDAY NIGHT. THURSDAY
SHOULD BE A BIT COOLER AS MID AND UPPER LEVEL CLOUD COVER LIMITS
DEEPER MIXING.

FORECAST MUCH MORE TRICKY FRIDAY AND SATURDAY AS MODEL SOLUTIONS
DIVERGE. GFS DEVELOPS A SLOW MOVING CLOSE LOW OVER THE WESTERN CONUS
WITH RELATIVELY DRY SOUTHWEST FLOW FOR THE FORECAST AREA. THE ECMWF
ON THE OTHER HAND SHOWS A MORE PROGRESSIVE WAVE SUPPRESSING THE RIDGE
OVER THE ROCKIES FRIDAY AND THEN DEVELOPING NORTHWEST FLOW BY
SATURDAY. IN OTHER WORDS THE ECMWF IS NOT ONLY COOLER BUT WOULD ALSO
SUGGESTS INCREASED PRECIPITATION CHANCES. NOT COMPLETELY CONFIDENT IN
EITHER MODEL BUT LEANING TOWARD THE ECMWF AS OVERALL WEATHER PATTERN
PERSISTENCE GOING ALL THE WAY BACK TO LAST WINTER FAVORS NORTHWEST
FLOW.


&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY EVENING)
ISSUED AT 1025 PM MDT SAT AUG 30 2014

COLD FRONT CONTINUES TO SLOWLY MOVE INTO THE AREA LATE THIS
EVENING. STILL KICKING OFF SOME THUNDERSTORMS OVER THE MOUNTAINS
TO THE WEST...BUT ELSEWHERE...RADAR SHOWING CONVECTION COMING TO
AN END. VFR CONDITIONS EXPECTED AT ALL TAF SITES OVERNIGHT. RETURN
OF GUSTY WINDS AND ISOLATED THUNDERSTORMS FOR SUNDAY AFTERNOON.


&&

.FIRE WEATHER...
ISSUED AT 244 AM MDT SUN AUG 31 2014

NO FIRE WEATHER CONCERNS THROUGH MONDAY...BUT THEN CONCERN OF NEAR
CRITICAL CONDITIONS INCREASE FOR TUESDAY AND WEDNESDAY. A STRONG
WEATHER DISTURBANCE AND ASSOCIATED COLD FRONT WILL MOVE ACROSS
THE AREA EARLY THIS MORNING. SHOWERS AND TSTORMS WILL CONTINUE
ACROSS SOUTHEAST WYOMING AND WESTERN NEBRASKA TODAY WITH GUSTY
WEST TO SOUTHWEST WINDS. DRIER CONDITIONS WILL DEVELOP BY MIDDLE
OF NEXT WEEK WHILE GUSTY WEST WINDS CONTINUE IN AREAS ALONG AND
WEST OF THE LARAMIE RANGE.

&&

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

$$

SHORT TERM...TJT
LONG TERM...SML
AVIATION...CLAYCOMB
FIRE WEATHER...TJT







000
FXUS65 KRIW 310917
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
317 AM MDT SUN AUG 31 2014

.SHORT TERM...TODAY THROUGH TUESDAY NIGHT

SHOWERS AND STORMS ONGOING AS A DYNAMIC TROUGH CONTINUES TO MOVE
THROUGH THE REGION. A COLD FRONT MOVED THROUGH ON SATURDAY WITH
ANOTHER REINFORCING COLD FRONT MOVING THROUGH FROM NORTHWEST TO
SOUTHEAST DURING THE MORNING HOURS...IT WILL BE COLD ENOUGH FOR SNOW
ABOVE 9KFT BEHIND THIS FRONT ESPECIALLY DURING THE MORNING HOURS.
ELSEWHERE...SCATTERED RAIN SHOWERS WITH EMBEDDED THUNDER THROUGHOUT
THE DAY WITH PERHAPS MORE OF AN EARLY SHOW OUT WEST GIVEN THE
EXPECTED TIMING OF THE TROUGH...HOWEVER THERE WILL BE ANOTHER WAVE
MOVING THROUGH LATE...BRINGING INCREASED SHOWER ACTIVITY BACK INTO
THE NORTHWEST AFTER SUNSET. SO A RATHER COMPLEX TROUGH WITH MANY
PIECES AND PARTS STILL EXPECTED TO AFFECT THE REGION THROUGH
TONIGHT. STRONGER STORMS WITH SMALL HAIL AND GUSTY WINDS WILL BE
MOST PROBABLE ACROSS NATRONA...EASTERN FREMONT AND SWEETWATER
COUNTIES NEAR A FRONTAL BOUNDARY BUT THERE WILL BE LESS CAPE AND
SHEAR TO WORK WITH TODAY SO NO SEVERE STORMS ARE EXPECTED.
OTHERWISE...MOST IF NOT ALL OF THE FORECAST AREA SHOULD SEE ANOTHER
STORM OR TWO BY TONIGHT.

ASIDE FROM THE RAIN CHANCES...IT WILL BE RATHER WINDY AGAIN TODAY AS
THE GRADIENT REMAINS TIGHT AND THUNDERSTORMS WILL STILL SEND OUT
SOME DECENT OUTFLOWS...THOUGH THEY ARE NOT EXPECTED TO BE AS STRONG
AS THEY WERE ON SATURDAY.

LABOR DAY...THE LAST SHORT WAVE THAT COULD STIR UP MORE SHOWERS AND
STORMS MOVES THROUGH EARLY IN THE DAY WITH EVENTUAL CLEARING AS THE
TROUGH CONTINUES TO MOVE EAST. THERE WILL ALSO BE SOME CONTINUED
BREEZY CONDITIONS AS THE SUBSIDENT SIDE OF THE TROUGH SWINGS THROUGH
AND FLOW SHIFTS TO THE NORTHWEST.

MUCH DRIER AIR MOVES IN ON TUESDAY AS FLOW TURNS MORE ZONAL. HIGH
PRESSURE BUILDING IN FROM THE SOUTH WILL ALSO BRING SOME WARMER AIR
WITH TEMPERATURES REBOUNDING BACK INTO THE 80S EAST OF THE DIVIDE.
THERE COULD BE SOME GUSTS TO 30 MPH ACROSS THE SOUTH ON
TUESDAY...WHICH COULD LEAD TO SOME FIRE WEATHER CONCERNS IN AREAS
WITH FLASHY GRASSY FUELS.

.LONG TERM...WEDNESDAY THROUGH SUNDAY

WEDNESDAY WILL BE DRY FOR MOST OF THE REGION. ISOLATED SHOWERS OR
STORMS FOR THE WESTERN MOUNTAINS AND NORTHERN MOUNTAINS. BREEZY
TO WINDY AREAS AND A WARM DAY. ISOLATED SHOWERS AND STORMS OVER
THE NORTH AND NORTHWEST WED NIGHT AS A TROUGH DEVELOPS OVER THE
PACIFIC NW EAST INTO MONTANA. THIS ELONGATED TROUGH WILL BE THE
FOCUS OF THE WEATHER THURSDAY THROUGH SUNDAY PER THE GFS MODEL.
THE ECMWF IS ALSO SHOWING THIS PATTERN THROUGH SATURDAY BUT MOVES
THE SYSTEM OUT FOR NEXT SUNDAY. A COLD FRONT PUSHES SOUTH INTO
NORTHERN WY LATE WED NIGHT AND THEN CONTINUES TO PUSH SOUTH ON
THURSDAY. THE FRONT LIES ALONG THE CONTINENTAL DIVIDE THURSDAY PM
PER THE GFS WHILE THE ECMWF MOVES IT THROUGH THE WHOLE AREA
THURSDAY. THUS THE FORECAST DILEMMA FOR HIGHS ON THURSDAY. PLUS
THE ECMWF IS COLDER WITH TEMPS ALOFT AND NEAR SURFACE TEMPS THAN
THE GFS THURSDAY...AS WELL AS FRIDAY AND SATURDAY. HAVE BLENDED
THE FORECAST HIGHS AND LOWS THURSDAY THROUGH SATURDAY KEEPING THE
BETTER COOLING EAST OF THE DIVIDE. MOISTURE IS FORECAST TO
INCREASE OVER THE REGION THURSDAY THROUGH SATURDAY IN A SW FLOW
ALOFT. MOISTURE SEEMS TO COME FROM TWO SOURCES...ONE FROM THE
TROUGH TO THE NORTH...THE OTHER FROM THE SW U.S. AROUND THE UPPER
HIGH. FOR NOW HAVE THE TYPICAL ISOLATED TO (IN SOME CASES)
SCATTERED SHOWERS AND STORMS OVER THE REGION THURSDAY THROUGH
SATURDAY. THE FRONTAL BOUNDARY WILL ALSO PLAY A ROLE IN THE PRECIP
CHANCE. OVERALL...A COMPLEX PATTERN FOR THOSE THREE DAYS. NEXT
SUNDAY LOOKS LIKE ISOLATED SHOWERS/STORMS AND WARMER HIGHS MOST
PLACES.

&&

.AVIATION.../12Z ISSUANCE/

THE SECOND PORTION OF AN UPPER TROUGH WILL MOVE ACROSS WESTERN
WYOMING THIS MORNING AND INTO THE HIGH PLAINS BY 00Z MONDAY.
SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS WILL CONTINUE ACROSS
MUCH OF THE AREA AHEAD OF THE TROUGH.  THIS COVERAGE WILL BE MOST
NUMEROUS ACROSS THE NORTH...ACROSS YELLOWSTONE NATIONAL PARK TO
VCNTY COD-BYG AND NORTH.  SNOW LEVELS WILL ALSO LOWER TO 9-10KFT IN
THIS AREA BY SUNRISE THIS MORNING WITH FQT MTN OBSCURATIONS AND
AREAS OF MVFR CONDITIONS.  THE OTHER AREA OF MORE ORGANIZED
SHRA/ISOLD TSRA COVERAGE IS EXPECTED ACROSS THE SOUTH OR VCNTY AND
SOUTH OF A KRKS-KCPR LINE THROUGH THE MORNING.  CONDITIONS WILL
IMPROVE WEST TO EAST THROUGH THE AFTERNOON AND EVENING WITH PATCHY
FOG DEVELOPING WHERE BETTER RAINS HAVE FALLEN...ESPECIALLY ACROSS
THE WESTERN VALLEYS AND THE NORTHERN BASINS.

&&

.FIRE WEATHER...

SHOWERS AND THUNDERSTORMS WITH A GOOD CHANCE OF WETTING RAIN
POSSIBLE ACROSS THE ENTIRE FORECAST AREA AGAIN TODAY. A COLD FRONT
MOVING THROUGH EARLY THIS MORNING WILL BRING ANOTHER CHANCE FOR SNOW
ABOVE 9KFT IN THE NORTHERN MOUNTAINS. THERE WILL BE A LULL IN THE
ACTIVITY FROM WEST TO EAST THIS AFTERNOON INTO THE EVENING BEFORE
THE NEXT WAVE MOVES IN...HOWEVER THIS WAVE WILL BE LESS IMPACTFUL
WITH ONLY A FEW SHOWERS AND STORMS EXPECTED ACROSS THE NORTHERN
THIRD OF THE STATE. IT WILL BE WINDY AGAIN TODAY...THOUGH NOT AS
GUSTY AS SATURDAY. TEMPERATURES WILL BE LOWER AND HUMIDITY HIGHER
TODAY WITH PLENTY OF CLOUD COVER...SO FIRE DANGER WILL BE LOW. IT
WILL BEGIN TO DRY OUT ON MONDAY...ESPECIALLY ACROSS THE SOUTH...BUT
CONTINUED COOL AND WINDY. MUCH WARMER AND DRIER AIR MOVES IN ON
TUESDAY WITH A STEADY WESTERLY WIND OF 20 TO 30 MPH ACROSS MUCH OF
RAWLINS AND CASPER DISPATCH WITH FIRE WEATHER CONCERNS POSSIBLY
RISING A BIT IF THE RH CAN DROP LOW ENOUGH.

&&

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

&&

$$

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








000
FXUS63 KUNR 310901
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
301 AM MDT SUN AUG 31 2014

.SHORT TERM...TODAY THROUGH MONDAY NIGHT
ISSUED AT 300 AM MDT SUN AUG 31 2014

LONGWAVE TROUGH AXIS IS CROSSING MT SOUTH TO WY WITH SEVERAL
EMBEDDED WAVES ROUNDING THE BASE OVER WY. IR SAT/NEIGHBORING RADAR
SHOWS SHRA OVER WY QUICKLY PUSHING EWD. MEANWHILE OVER THE
CWA...SMALL SCALE SUBSIDENCE BEHIND THE WAVE DEPARTING E OF THE CWA
IS LEAVING QUIET WEATHER OVER THE AREA ATTM. THE TROUGH AXIS WILL
CROSS THE CWA TODAY BRINGING SHRA/TSRA TO THE AREA. MLCAPE WILL BE
WEAKER THAN YESTERDAY...500 TO 1000 J/KG TODAY WITH LITTLE TO NO
CAP...STILL ENOUGH FOR SOME STORM DEVELOPMENT. STRONG FORCING W/
THIS WAVE WARRANTS KEEPING AND EXPANDING LIKELY POPS OVER MUCH OF
THE CWA. GIVEN THE SPEED OF THIS SYSTEM...QPF IS EXPECTED TO BE
UNDER A HALF INCH. TEMPERATURES WILL BE A COOL 60S OVER NE WY AND
THE BLACK HILLS...ESPECIALLY AS CLOUDS REMAIN OVER THOSE AREA MUCH
OF THE DAY. THE SD PLAINS ARE EXPECTED TO REACH INTO THE 70S AND
MORNING HEATING COMMENCES BEFORE THE CLOUDS ROLL IN. BREEZY NW
WINDS WILL DEVELOP AS THE SYSTEM MOVES THROUGH WITH REINFORCING
COLD AIR ADVECTION.

SEVERAL UPPER WAVES DIVING DOWN THE BACKSIDE OF THE UPPER TROUGH
OVER THE NRN ROCKIES REGION WILL SLOW DOWN THE EWD PROGRESSION OF
THE OVERALL PATTERN. A SERIES OF WAVES ARE PROGGED TO CROSS THE CWA
MONDAY...WITH A REPEAT OF SHOWERS/STORMS CROSSING THE AREA THROUGH
THE DAY. WITH WEAKER FORCING AND LESS MOISTURE IN THE
ATMOSPHERE...WILL GO WITH CHANCE POPS FOR SHRA ACTIVITY. MLCAPE WILL
BE WEAKER MONDAY THAN TODAY...BUT COULD STILL SEE ISOLATED STORMS.
TEMPERATURES WILL BE IN THE MID 60S TO UPPER 70S. PRECIP WILL END
OVER THE AREA BY LATE MON NIGHT.

&&

.LONG TERM...TUESDAY THROUGH SATURDAY
ISSUED AT 300 AM MDT SUN AUG 31 2014

UPPER TROUGH DIGS ACROSS THE PACIFIC NORTHWEST
TUESDAY/WEDNESDAY...BRINGING FLAT UPPER RIDGE OVER THE NORTHERN
PLAINS. THIS WILL RESULT IN DRY CONDITIONS WITH TEMPERATURES NEAR
OR SLIGHTLY ABOVE AVERAGE. STRONG WAVE LIFTS ACROSS THE NORTHERN
ROCKIES LATE WEDNESDAY/THURSDAY...PUSHING COLD FRONT THROUGH THE
NORTHERN PLAINS. BEST FORCING STAYS NORTH OF FORECAST
AREA...THOUGH A FEW POST FRONTAL SHOWERS/THUNDERSTORMS POSSIBLE
THURSDAY. MODELS DIVERGE FOR THE WEEKEND...WITH ECMWF BRINGING
STRONG SHORTWAVE IN NORTHWEST FLOW SATURDAY...WHILE GFS MAINTAINS
UPPER TROF OVER WESTERN CONUS AND RIDGING OVER THE PLAINS. TRENDED
TOWARDS ECMWF...WITH COOLER TEMPERATURES AND SMALL POPS.

&&

.AVIATION...FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING
ISSUED AT 300 AM MDT SUN AUG 31 2014

SCATTERED SHOWERS AND THUNDERSTORMS WILL BE FOUND ACROSS THE AREA
TODAY. LCL MVFR CIGS/IFR VSBY POSSIBLE WITH THE STRONGER STORMS.

&&

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

$$

SHORT TERM...13
LONG TERM...7
AVIATION...7







000
FXUS63 KUNR 310901
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
301 AM MDT SUN AUG 31 2014

.SHORT TERM...TODAY THROUGH MONDAY NIGHT
ISSUED AT 300 AM MDT SUN AUG 31 2014

LONGWAVE TROUGH AXIS IS CROSSING MT SOUTH TO WY WITH SEVERAL
EMBEDDED WAVES ROUNDING THE BASE OVER WY. IR SAT/NEIGHBORING RADAR
SHOWS SHRA OVER WY QUICKLY PUSHING EWD. MEANWHILE OVER THE
CWA...SMALL SCALE SUBSIDENCE BEHIND THE WAVE DEPARTING E OF THE CWA
IS LEAVING QUIET WEATHER OVER THE AREA ATTM. THE TROUGH AXIS WILL
CROSS THE CWA TODAY BRINGING SHRA/TSRA TO THE AREA. MLCAPE WILL BE
WEAKER THAN YESTERDAY...500 TO 1000 J/KG TODAY WITH LITTLE TO NO
CAP...STILL ENOUGH FOR SOME STORM DEVELOPMENT. STRONG FORCING W/
THIS WAVE WARRANTS KEEPING AND EXPANDING LIKELY POPS OVER MUCH OF
THE CWA. GIVEN THE SPEED OF THIS SYSTEM...QPF IS EXPECTED TO BE
UNDER A HALF INCH. TEMPERATURES WILL BE A COOL 60S OVER NE WY AND
THE BLACK HILLS...ESPECIALLY AS CLOUDS REMAIN OVER THOSE AREA MUCH
OF THE DAY. THE SD PLAINS ARE EXPECTED TO REACH INTO THE 70S AND
MORNING HEATING COMMENCES BEFORE THE CLOUDS ROLL IN. BREEZY NW
WINDS WILL DEVELOP AS THE SYSTEM MOVES THROUGH WITH REINFORCING
COLD AIR ADVECTION.

SEVERAL UPPER WAVES DIVING DOWN THE BACKSIDE OF THE UPPER TROUGH
OVER THE NRN ROCKIES REGION WILL SLOW DOWN THE EWD PROGRESSION OF
THE OVERALL PATTERN. A SERIES OF WAVES ARE PROGGED TO CROSS THE CWA
MONDAY...WITH A REPEAT OF SHOWERS/STORMS CROSSING THE AREA THROUGH
THE DAY. WITH WEAKER FORCING AND LESS MOISTURE IN THE
ATMOSPHERE...WILL GO WITH CHANCE POPS FOR SHRA ACTIVITY. MLCAPE WILL
BE WEAKER MONDAY THAN TODAY...BUT COULD STILL SEE ISOLATED STORMS.
TEMPERATURES WILL BE IN THE MID 60S TO UPPER 70S. PRECIP WILL END
OVER THE AREA BY LATE MON NIGHT.

&&

.LONG TERM...TUESDAY THROUGH SATURDAY
ISSUED AT 300 AM MDT SUN AUG 31 2014

UPPER TROUGH DIGS ACROSS THE PACIFIC NORTHWEST
TUESDAY/WEDNESDAY...BRINGING FLAT UPPER RIDGE OVER THE NORTHERN
PLAINS. THIS WILL RESULT IN DRY CONDITIONS WITH TEMPERATURES NEAR
OR SLIGHTLY ABOVE AVERAGE. STRONG WAVE LIFTS ACROSS THE NORTHERN
ROCKIES LATE WEDNESDAY/THURSDAY...PUSHING COLD FRONT THROUGH THE
NORTHERN PLAINS. BEST FORCING STAYS NORTH OF FORECAST
AREA...THOUGH A FEW POST FRONTAL SHOWERS/THUNDERSTORMS POSSIBLE
THURSDAY. MODELS DIVERGE FOR THE WEEKEND...WITH ECMWF BRINGING
STRONG SHORTWAVE IN NORTHWEST FLOW SATURDAY...WHILE GFS MAINTAINS
UPPER TROF OVER WESTERN CONUS AND RIDGING OVER THE PLAINS. TRENDED
TOWARDS ECMWF...WITH COOLER TEMPERATURES AND SMALL POPS.

&&

.AVIATION...FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING
ISSUED AT 300 AM MDT SUN AUG 31 2014

SCATTERED SHOWERS AND THUNDERSTORMS WILL BE FOUND ACROSS THE AREA
TODAY. LCL MVFR CIGS/IFR VSBY POSSIBLE WITH THE STRONGER STORMS.

&&

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

$$

SHORT TERM...13
LONG TERM...7
AVIATION...7








000
FXUS65 KRIW 310558
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
1155 PM MDT SAT AUG 30 2014

.SHORT TERM...TONIGHT THROUGH SUNDAY (ISSUED AT 222 PM MDT)

PROGRESSIVE EVOLVING UPR PATTERN WITH BROADENING TROF ACROSS THE WRN
CONUS...SW FLOW OVERHEAD WY...AND SW RIDGING OVR THE PLAINS. FIRST
EMBEDDED SW WITHIN THE TROF IS HEADING INTO THE WRN/NWRN PORTIONS OF
THE STATE THIS MORNING...AND WILL CONTINUE TO EXPAND ACROSS WY
THROUGHOUT THE DAY AND NIGHT PERIODS. AT THE SFC...DEVELOPING LOW
PRESSURE OVR THE BIG HORN BASIN...WITH WARM FRONT EXTENDING OF TO
THE E/SE...AND COLD FRONT(S) OFF TO THE N/NW FROM THIS LOW.

TODAY/TONIGHT...THE PROGRESSIVE NATURE OF THE UPR LVLS WILL CONTINUE
TO SPREAD STRONGER UPR LVL FLOW OVERHEAD RESULTING IN INCREASED NET
UPWARD LIFT THRU TODAY AND OVERNIGHT. THIS WILL CONTINUE TO GREATLY
IMPROVE CONVECTIVE CHANCES AND GROWTH POTENTIAL TODAY AND INTO THE
EVENING PERIOD. A FEW STRONG/MARGINALLY SVR STORMS EXPECTED WITH ML
CAPE RANGING FROM 500 TO 1000 J/KG AND DEEP SHEAR OF 40 TO 50 KTS
THIS AFTERNOON OVER THE NORTHERN ZONES. STRONGER STORMS WILL BE
CHARACTERIZED AS FAST MOVING AT 30 TO 40 KTS...WITH HAIL AND STRONG
GUSTY WINDS APPROACHING SEVERE LEVELS FOR A FEW HOURS THIS
AFTERNOON. ELSEWHERE...STORM WILL HAVE STRONG GUSTY WINDS WITH BRIEF
HEAVY RAIN AND SMALL HAIL. SHEAR TODAY IS PRIMARILY AVAILABLE IN THE
FORM OF SPEED SHEAR W/ HEIGHT...WITH INCREASING UNIDIRECTIONAL SW
FLOW ACROSS MUCH OF THE CWA. THIS WILL ALSO LEND ITSELF TO AMBIENT
WEST TO SOUTHWEST WINDS BLOWING 20 PLUS MPH TO BEGIN WITH.
OVERALL...SIGNIFICANT HYDRO POTENTIAL DOES NOT LOOK TO BE AN ISSUE
AT THIS TIME WITH THESE FAST MOVING STORMS...EXCEPT IN THE CASE OF A
TRAINING SITUATION. CONVECTIVE SNOW SHOWERS WILL ALSO BE POSSIBLE
OVERNIGHT AND THROUGH THE DAY SUNDAY...FIRST STARTING OUR ABOVE
10500 FT THIS EVENING...AND DECREASING AROUND 9000 FT BY EVENING
SUNDAY.

SUNDAY...THE UPR TROF CONTINUES CROSSING/EXPANDING ACROSS THE STATE
FROM W TO E...WITH MUCH COOLER CONDITIONS FOR SURE BUT CONTINUED
GUSTY W TO WSW WINDS ACROSS THE SRN FA...AND GUSTY N TO NW WINDS
BEHIND THE FRONT...WITH ANOTHER SFC COLD FRONT POISED TO ENTER THE
STATE FROM THE NORTH THROUGH THE DAY. SHOWERS AND ISOLATED THUNDER
WILL BE RATHER PREVALENT ACROSS THE ENTIRE CWA FROM MORNING THROUGH
EARLY AFTERNOON BEFORE DECREASING FROM W TO E LATER IN THE DAY AND
EVENING. STRONGER STORMS WITH SMALL HAIL AND GUSTY WINDS WILL BE
MOST PROBABLY ACROSS NATRONA AND EASTERN FREMONT AND SWEETWATER
COUNTIES NEAR A FRONTAL BOUNDARY.

.LONG TERM...SUNDAY NIGHT THROUGH SATURDAY

SUNDAY NIGHT AN UPPER LEVEL LOW PRESSURE TROUGH WILL BE PASSING
THROUGH THE AREA SUPPORTING SOME SHOWERS AND ISOLATED
THUNDERSTORMS...MOST NUMEROUS OVER THE NORTHERN MOUNTAINS IN THE
EVENING.  SOME CONVECTION WILL LINGER THROUGH THE NIGHT.

MONDAY AND MONDAY NIGHT AS THE TROUGH CONTINUE TO MOVE EAST...
HIGH PRESSURE RIDGING WILL OCCUR OVER THE PACIFIC NORTHWEST.  SOME
SHOWERS MAY LINGER ACROSS THE WEST BUT THE MAIN TREND WILL BE FOR
DRYING WITH BREEZY TO WINDY CONDITIONS ACROSS THE SOUTH INTO
CENTRAL AREAS.

TUESDAY AND TUESDAY NIGHT DRY HIGH PRESSURE IS EXPECTED TO DOMINATE
THE WEATHER ACROSS THE AREA WITH INCREASING WEST TO SOUTHWEST WINDS
CENTRAL AND SOUTH WITH GENERAL WARMING.

WEDNESDAY AND WEDNESDAY NIGHT  SOME MID LEVEL CLOUDS ARE EXPECTED TO
MOVE UP FROM THE GREAT BASIN IN THE AFTERNOON...OTHERWISE THE DRY
HIGH PRESSURE IS EXPECTED TO CONTINUE TO DOMINATE THE WEATHER WITH
CONTINUED SOUTHWEST WINDS ACROSS THE CENTRAL AND SOUTH.

THURSDAY AND THURSDAY NIGHT  HIGH PRESSURE WILL SHIFT EAST WITH
INCREASING SOUTHWEST FLOW ALOFT BRINGING SOME PACIFIC MOISTURE ALOFT
OVER THE AREA.  SHOWERS ARE EXPECTED TO DEVELOP WITH ISOLATED
THUNDERSTORMS IN THE AFTERNOON...MOST NUMEROUS OVER THE WESTERN AND
CENTRAL MOUNTAINS.  INCREASED CLOUD COVER WILL BRING SOME COOLING.

FRIDAY AND FRIDAY NIGHT  SHOWERS AND ISOLATED THUNDERSTORMS ARE
EXPECTED TO INCREASE OVER THE AREA AS PACIFIC MOISTURE INCREASES IN
SOUTHWEST FLOW ALOFT.  A WEAK COLD FRONT WILL MOVE SLOWLY SOUTH FROM
MONTANA INTO NORTHERN WYOMING.

SATURDAY SOUTHWEST FLOW ALOFT WILL REMAIN IN PLACE OVER THE AREA
WITH A STREAM OF PACIFIC MOISTURE CONTINUING TO ADVECT INTO THE AREA
SUPPORTING SCATTERED SHOWERS AND SOME ISOLATED AFTERNOON
THUNDERSTORMS.  A FRONT IS EXPECTED TO HANG OUT ACROSS NORTHERN
WYOMING OSCILLATING NORTH AND SOUTH WITH SOME COOLING.  THE FRONT
WILL BE FIGHTING THE FLOW ALOFT AND THE AMOUNT OF COOLING IS IN
QUESTION.  OVERALL MODELS ARE IN FAIR AGREEMENT THROUGH THE MID TERM
AND EXTENDED FORECAST WITH THE GREATEST MODEL SPREAD TO THE NORTH
OVER CANADA...ESPECIALLY IN THE HUDSON BAY AREA.

&&

.AVIATION.../06Z ISSUANCE/

THE SECOND PORTION OF AN UPPER TROUGH WILL MOVE ACROSS WESTERN
WYOMING THIS MORNING AND INTO THE HIGH PLAINS BY 00Z MONDAY.
SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS WILL CONTINUE ACROSS
MUCH OF THE AREA AHEAD OF THE TROUGH.  THIS COVERAGE WILL BE MOST
NUMEROUS ACROSS THE NORTH...ACROSS YELLOWSTONE NATIONAL PARK TO
VCNTY COD-BYG AND NORTH.  SNOW LEVELS WILL ALSO LOWER TO 9-10KFT IN
THIS AREA BY SUNRISE WITH FQT MTN OBSCURATIONS AND AREAS OF
MVFR CONDITIONS.  THE OTHER AREA OF MORE ORGANIZED SHRA/ISOLD TSRA
COVERAGE IS EXPECTED ACROSS THE SOUTH OR VCNTY AND SOUTH OF A
KRKS-KCPR LINE THROUGH THIS MORNING.  CONDITIONS WILL IMPROVE WEST TO
EAST THROUGH THE AFTERNOON AND EVENING WITH PATCHY FOG DEVELOPING
WHERE BETTER RAINS HAVE FALLEN...ESPECIALLY ACROSS THE WESTERN
VALLEYS AND THE NORTHERN BASINS.

&&

.FIRE WEATHER...

AN EVOLVING LARGE UPPER LEVEL TROUGH WITH SEVERAL EMBEDDED
DISTURBANCES WILL PUSH ACROSS THE FORECAST AREA THROUGH SUNDAY AND
PART OF MONDAY. THIS SYSTEM WILL DESTABILIZE THE ATMOSPHERE AND PUSH
A FEW COLD FRONTS SOUTH ACROSS NORTH AND CENTRAL WYOMING THIS
AFTERNOON...AGAIN SUNDAY MORNING...AND FINALLY MONDAY AFTERNOON.
TODAY`S FRONT WILL BE THE FOCUS FOR STRONGER THUNDERSTORMS...
PRIMARILY NEAR AND NORTH OF A DUBOIS TO WORLAND TO GILLETTE LINE.
THESE STORMS WILL BE MOVING QUITE FAST AT AROUND 35 TO 40 KTS...WITH
SOME OF THESE STORMS CAPABLE OF MARGINALLY SEVERE HAIL AND WIND
GUSTS. SOUTH OF THE FRONT(S)...WEST TO WEST SOUTHWEST WINDS AT 20-25
MPH WITH GUSTS TO 40 MPH WILL BE POSSIBLE ALONG WITH MINIMUM RH
VALUES OF AROUND 20 PERCENT. THIS TOGETHER WITH ISOLATED TO WIDELY
SCT THUNDERSTORMS AND ERRATIC OUTFLOW WIND GUSTS NEAR 45KTS WILL
BRING ENHANCED FIRE DANGER TO THIS REGION FOR A FEW HOURS.

&&

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

$$

SHORT TERM...BRAUN
LONG TERM...C.BAKER
AVIATION...AEM
FIRE WEATHER...BRAUN








000
FXUS65 KRIW 310558
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
1155 PM MDT SAT AUG 30 2014

.SHORT TERM...TONIGHT THROUGH SUNDAY (ISSUED AT 222 PM MDT)

PROGRESSIVE EVOLVING UPR PATTERN WITH BROADENING TROF ACROSS THE WRN
CONUS...SW FLOW OVERHEAD WY...AND SW RIDGING OVR THE PLAINS. FIRST
EMBEDDED SW WITHIN THE TROF IS HEADING INTO THE WRN/NWRN PORTIONS OF
THE STATE THIS MORNING...AND WILL CONTINUE TO EXPAND ACROSS WY
THROUGHOUT THE DAY AND NIGHT PERIODS. AT THE SFC...DEVELOPING LOW
PRESSURE OVR THE BIG HORN BASIN...WITH WARM FRONT EXTENDING OF TO
THE E/SE...AND COLD FRONT(S) OFF TO THE N/NW FROM THIS LOW.

TODAY/TONIGHT...THE PROGRESSIVE NATURE OF THE UPR LVLS WILL CONTINUE
TO SPREAD STRONGER UPR LVL FLOW OVERHEAD RESULTING IN INCREASED NET
UPWARD LIFT THRU TODAY AND OVERNIGHT. THIS WILL CONTINUE TO GREATLY
IMPROVE CONVECTIVE CHANCES AND GROWTH POTENTIAL TODAY AND INTO THE
EVENING PERIOD. A FEW STRONG/MARGINALLY SVR STORMS EXPECTED WITH ML
CAPE RANGING FROM 500 TO 1000 J/KG AND DEEP SHEAR OF 40 TO 50 KTS
THIS AFTERNOON OVER THE NORTHERN ZONES. STRONGER STORMS WILL BE
CHARACTERIZED AS FAST MOVING AT 30 TO 40 KTS...WITH HAIL AND STRONG
GUSTY WINDS APPROACHING SEVERE LEVELS FOR A FEW HOURS THIS
AFTERNOON. ELSEWHERE...STORM WILL HAVE STRONG GUSTY WINDS WITH BRIEF
HEAVY RAIN AND SMALL HAIL. SHEAR TODAY IS PRIMARILY AVAILABLE IN THE
FORM OF SPEED SHEAR W/ HEIGHT...WITH INCREASING UNIDIRECTIONAL SW
FLOW ACROSS MUCH OF THE CWA. THIS WILL ALSO LEND ITSELF TO AMBIENT
WEST TO SOUTHWEST WINDS BLOWING 20 PLUS MPH TO BEGIN WITH.
OVERALL...SIGNIFICANT HYDRO POTENTIAL DOES NOT LOOK TO BE AN ISSUE
AT THIS TIME WITH THESE FAST MOVING STORMS...EXCEPT IN THE CASE OF A
TRAINING SITUATION. CONVECTIVE SNOW SHOWERS WILL ALSO BE POSSIBLE
OVERNIGHT AND THROUGH THE DAY SUNDAY...FIRST STARTING OUR ABOVE
10500 FT THIS EVENING...AND DECREASING AROUND 9000 FT BY EVENING
SUNDAY.

SUNDAY...THE UPR TROF CONTINUES CROSSING/EXPANDING ACROSS THE STATE
FROM W TO E...WITH MUCH COOLER CONDITIONS FOR SURE BUT CONTINUED
GUSTY W TO WSW WINDS ACROSS THE SRN FA...AND GUSTY N TO NW WINDS
BEHIND THE FRONT...WITH ANOTHER SFC COLD FRONT POISED TO ENTER THE
STATE FROM THE NORTH THROUGH THE DAY. SHOWERS AND ISOLATED THUNDER
WILL BE RATHER PREVALENT ACROSS THE ENTIRE CWA FROM MORNING THROUGH
EARLY AFTERNOON BEFORE DECREASING FROM W TO E LATER IN THE DAY AND
EVENING. STRONGER STORMS WITH SMALL HAIL AND GUSTY WINDS WILL BE
MOST PROBABLY ACROSS NATRONA AND EASTERN FREMONT AND SWEETWATER
COUNTIES NEAR A FRONTAL BOUNDARY.

.LONG TERM...SUNDAY NIGHT THROUGH SATURDAY

SUNDAY NIGHT AN UPPER LEVEL LOW PRESSURE TROUGH WILL BE PASSING
THROUGH THE AREA SUPPORTING SOME SHOWERS AND ISOLATED
THUNDERSTORMS...MOST NUMEROUS OVER THE NORTHERN MOUNTAINS IN THE
EVENING.  SOME CONVECTION WILL LINGER THROUGH THE NIGHT.

MONDAY AND MONDAY NIGHT AS THE TROUGH CONTINUE TO MOVE EAST...
HIGH PRESSURE RIDGING WILL OCCUR OVER THE PACIFIC NORTHWEST.  SOME
SHOWERS MAY LINGER ACROSS THE WEST BUT THE MAIN TREND WILL BE FOR
DRYING WITH BREEZY TO WINDY CONDITIONS ACROSS THE SOUTH INTO
CENTRAL AREAS.

TUESDAY AND TUESDAY NIGHT DRY HIGH PRESSURE IS EXPECTED TO DOMINATE
THE WEATHER ACROSS THE AREA WITH INCREASING WEST TO SOUTHWEST WINDS
CENTRAL AND SOUTH WITH GENERAL WARMING.

WEDNESDAY AND WEDNESDAY NIGHT  SOME MID LEVEL CLOUDS ARE EXPECTED TO
MOVE UP FROM THE GREAT BASIN IN THE AFTERNOON...OTHERWISE THE DRY
HIGH PRESSURE IS EXPECTED TO CONTINUE TO DOMINATE THE WEATHER WITH
CONTINUED SOUTHWEST WINDS ACROSS THE CENTRAL AND SOUTH.

THURSDAY AND THURSDAY NIGHT  HIGH PRESSURE WILL SHIFT EAST WITH
INCREASING SOUTHWEST FLOW ALOFT BRINGING SOME PACIFIC MOISTURE ALOFT
OVER THE AREA.  SHOWERS ARE EXPECTED TO DEVELOP WITH ISOLATED
THUNDERSTORMS IN THE AFTERNOON...MOST NUMEROUS OVER THE WESTERN AND
CENTRAL MOUNTAINS.  INCREASED CLOUD COVER WILL BRING SOME COOLING.

FRIDAY AND FRIDAY NIGHT  SHOWERS AND ISOLATED THUNDERSTORMS ARE
EXPECTED TO INCREASE OVER THE AREA AS PACIFIC MOISTURE INCREASES IN
SOUTHWEST FLOW ALOFT.  A WEAK COLD FRONT WILL MOVE SLOWLY SOUTH FROM
MONTANA INTO NORTHERN WYOMING.

SATURDAY SOUTHWEST FLOW ALOFT WILL REMAIN IN PLACE OVER THE AREA
WITH A STREAM OF PACIFIC MOISTURE CONTINUING TO ADVECT INTO THE AREA
SUPPORTING SCATTERED SHOWERS AND SOME ISOLATED AFTERNOON
THUNDERSTORMS.  A FRONT IS EXPECTED TO HANG OUT ACROSS NORTHERN
WYOMING OSCILLATING NORTH AND SOUTH WITH SOME COOLING.  THE FRONT
WILL BE FIGHTING THE FLOW ALOFT AND THE AMOUNT OF COOLING IS IN
QUESTION.  OVERALL MODELS ARE IN FAIR AGREEMENT THROUGH THE MID TERM
AND EXTENDED FORECAST WITH THE GREATEST MODEL SPREAD TO THE NORTH
OVER CANADA...ESPECIALLY IN THE HUDSON BAY AREA.

&&

.AVIATION.../06Z ISSUANCE/

THE SECOND PORTION OF AN UPPER TROUGH WILL MOVE ACROSS WESTERN
WYOMING THIS MORNING AND INTO THE HIGH PLAINS BY 00Z MONDAY.
SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS WILL CONTINUE ACROSS
MUCH OF THE AREA AHEAD OF THE TROUGH.  THIS COVERAGE WILL BE MOST
NUMEROUS ACROSS THE NORTH...ACROSS YELLOWSTONE NATIONAL PARK TO
VCNTY COD-BYG AND NORTH.  SNOW LEVELS WILL ALSO LOWER TO 9-10KFT IN
THIS AREA BY SUNRISE WITH FQT MTN OBSCURATIONS AND AREAS OF
MVFR CONDITIONS.  THE OTHER AREA OF MORE ORGANIZED SHRA/ISOLD TSRA
COVERAGE IS EXPECTED ACROSS THE SOUTH OR VCNTY AND SOUTH OF A
KRKS-KCPR LINE THROUGH THIS MORNING.  CONDITIONS WILL IMPROVE WEST TO
EAST THROUGH THE AFTERNOON AND EVENING WITH PATCHY FOG DEVELOPING
WHERE BETTER RAINS HAVE FALLEN...ESPECIALLY ACROSS THE WESTERN
VALLEYS AND THE NORTHERN BASINS.

&&

.FIRE WEATHER...

AN EVOLVING LARGE UPPER LEVEL TROUGH WITH SEVERAL EMBEDDED
DISTURBANCES WILL PUSH ACROSS THE FORECAST AREA THROUGH SUNDAY AND
PART OF MONDAY. THIS SYSTEM WILL DESTABILIZE THE ATMOSPHERE AND PUSH
A FEW COLD FRONTS SOUTH ACROSS NORTH AND CENTRAL WYOMING THIS
AFTERNOON...AGAIN SUNDAY MORNING...AND FINALLY MONDAY AFTERNOON.
TODAY`S FRONT WILL BE THE FOCUS FOR STRONGER THUNDERSTORMS...
PRIMARILY NEAR AND NORTH OF A DUBOIS TO WORLAND TO GILLETTE LINE.
THESE STORMS WILL BE MOVING QUITE FAST AT AROUND 35 TO 40 KTS...WITH
SOME OF THESE STORMS CAPABLE OF MARGINALLY SEVERE HAIL AND WIND
GUSTS. SOUTH OF THE FRONT(S)...WEST TO WEST SOUTHWEST WINDS AT 20-25
MPH WITH GUSTS TO 40 MPH WILL BE POSSIBLE ALONG WITH MINIMUM RH
VALUES OF AROUND 20 PERCENT. THIS TOGETHER WITH ISOLATED TO WIDELY
SCT THUNDERSTORMS AND ERRATIC OUTFLOW WIND GUSTS NEAR 45KTS WILL
BRING ENHANCED FIRE DANGER TO THIS REGION FOR A FEW HOURS.

&&

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

$$

SHORT TERM...BRAUN
LONG TERM...C.BAKER
AVIATION...AEM
FIRE WEATHER...BRAUN








000
FXUS65 KRIW 310558
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
1155 PM MDT SAT AUG 30 2014

.SHORT TERM...TONIGHT THROUGH SUNDAY (ISSUED AT 222 PM MDT)

PROGRESSIVE EVOLVING UPR PATTERN WITH BROADENING TROF ACROSS THE WRN
CONUS...SW FLOW OVERHEAD WY...AND SW RIDGING OVR THE PLAINS. FIRST
EMBEDDED SW WITHIN THE TROF IS HEADING INTO THE WRN/NWRN PORTIONS OF
THE STATE THIS MORNING...AND WILL CONTINUE TO EXPAND ACROSS WY
THROUGHOUT THE DAY AND NIGHT PERIODS. AT THE SFC...DEVELOPING LOW
PRESSURE OVR THE BIG HORN BASIN...WITH WARM FRONT EXTENDING OF TO
THE E/SE...AND COLD FRONT(S) OFF TO THE N/NW FROM THIS LOW.

TODAY/TONIGHT...THE PROGRESSIVE NATURE OF THE UPR LVLS WILL CONTINUE
TO SPREAD STRONGER UPR LVL FLOW OVERHEAD RESULTING IN INCREASED NET
UPWARD LIFT THRU TODAY AND OVERNIGHT. THIS WILL CONTINUE TO GREATLY
IMPROVE CONVECTIVE CHANCES AND GROWTH POTENTIAL TODAY AND INTO THE
EVENING PERIOD. A FEW STRONG/MARGINALLY SVR STORMS EXPECTED WITH ML
CAPE RANGING FROM 500 TO 1000 J/KG AND DEEP SHEAR OF 40 TO 50 KTS
THIS AFTERNOON OVER THE NORTHERN ZONES. STRONGER STORMS WILL BE
CHARACTERIZED AS FAST MOVING AT 30 TO 40 KTS...WITH HAIL AND STRONG
GUSTY WINDS APPROACHING SEVERE LEVELS FOR A FEW HOURS THIS
AFTERNOON. ELSEWHERE...STORM WILL HAVE STRONG GUSTY WINDS WITH BRIEF
HEAVY RAIN AND SMALL HAIL. SHEAR TODAY IS PRIMARILY AVAILABLE IN THE
FORM OF SPEED SHEAR W/ HEIGHT...WITH INCREASING UNIDIRECTIONAL SW
FLOW ACROSS MUCH OF THE CWA. THIS WILL ALSO LEND ITSELF TO AMBIENT
WEST TO SOUTHWEST WINDS BLOWING 20 PLUS MPH TO BEGIN WITH.
OVERALL...SIGNIFICANT HYDRO POTENTIAL DOES NOT LOOK TO BE AN ISSUE
AT THIS TIME WITH THESE FAST MOVING STORMS...EXCEPT IN THE CASE OF A
TRAINING SITUATION. CONVECTIVE SNOW SHOWERS WILL ALSO BE POSSIBLE
OVERNIGHT AND THROUGH THE DAY SUNDAY...FIRST STARTING OUR ABOVE
10500 FT THIS EVENING...AND DECREASING AROUND 9000 FT BY EVENING
SUNDAY.

SUNDAY...THE UPR TROF CONTINUES CROSSING/EXPANDING ACROSS THE STATE
FROM W TO E...WITH MUCH COOLER CONDITIONS FOR SURE BUT CONTINUED
GUSTY W TO WSW WINDS ACROSS THE SRN FA...AND GUSTY N TO NW WINDS
BEHIND THE FRONT...WITH ANOTHER SFC COLD FRONT POISED TO ENTER THE
STATE FROM THE NORTH THROUGH THE DAY. SHOWERS AND ISOLATED THUNDER
WILL BE RATHER PREVALENT ACROSS THE ENTIRE CWA FROM MORNING THROUGH
EARLY AFTERNOON BEFORE DECREASING FROM W TO E LATER IN THE DAY AND
EVENING. STRONGER STORMS WITH SMALL HAIL AND GUSTY WINDS WILL BE
MOST PROBABLY ACROSS NATRONA AND EASTERN FREMONT AND SWEETWATER
COUNTIES NEAR A FRONTAL BOUNDARY.

.LONG TERM...SUNDAY NIGHT THROUGH SATURDAY

SUNDAY NIGHT AN UPPER LEVEL LOW PRESSURE TROUGH WILL BE PASSING
THROUGH THE AREA SUPPORTING SOME SHOWERS AND ISOLATED
THUNDERSTORMS...MOST NUMEROUS OVER THE NORTHERN MOUNTAINS IN THE
EVENING.  SOME CONVECTION WILL LINGER THROUGH THE NIGHT.

MONDAY AND MONDAY NIGHT AS THE TROUGH CONTINUE TO MOVE EAST...
HIGH PRESSURE RIDGING WILL OCCUR OVER THE PACIFIC NORTHWEST.  SOME
SHOWERS MAY LINGER ACROSS THE WEST BUT THE MAIN TREND WILL BE FOR
DRYING WITH BREEZY TO WINDY CONDITIONS ACROSS THE SOUTH INTO
CENTRAL AREAS.

TUESDAY AND TUESDAY NIGHT DRY HIGH PRESSURE IS EXPECTED TO DOMINATE
THE WEATHER ACROSS THE AREA WITH INCREASING WEST TO SOUTHWEST WINDS
CENTRAL AND SOUTH WITH GENERAL WARMING.

WEDNESDAY AND WEDNESDAY NIGHT  SOME MID LEVEL CLOUDS ARE EXPECTED TO
MOVE UP FROM THE GREAT BASIN IN THE AFTERNOON...OTHERWISE THE DRY
HIGH PRESSURE IS EXPECTED TO CONTINUE TO DOMINATE THE WEATHER WITH
CONTINUED SOUTHWEST WINDS ACROSS THE CENTRAL AND SOUTH.

THURSDAY AND THURSDAY NIGHT  HIGH PRESSURE WILL SHIFT EAST WITH
INCREASING SOUTHWEST FLOW ALOFT BRINGING SOME PACIFIC MOISTURE ALOFT
OVER THE AREA.  SHOWERS ARE EXPECTED TO DEVELOP WITH ISOLATED
THUNDERSTORMS IN THE AFTERNOON...MOST NUMEROUS OVER THE WESTERN AND
CENTRAL MOUNTAINS.  INCREASED CLOUD COVER WILL BRING SOME COOLING.

FRIDAY AND FRIDAY NIGHT  SHOWERS AND ISOLATED THUNDERSTORMS ARE
EXPECTED TO INCREASE OVER THE AREA AS PACIFIC MOISTURE INCREASES IN
SOUTHWEST FLOW ALOFT.  A WEAK COLD FRONT WILL MOVE SLOWLY SOUTH FROM
MONTANA INTO NORTHERN WYOMING.

SATURDAY SOUTHWEST FLOW ALOFT WILL REMAIN IN PLACE OVER THE AREA
WITH A STREAM OF PACIFIC MOISTURE CONTINUING TO ADVECT INTO THE AREA
SUPPORTING SCATTERED SHOWERS AND SOME ISOLATED AFTERNOON
THUNDERSTORMS.  A FRONT IS EXPECTED TO HANG OUT ACROSS NORTHERN
WYOMING OSCILLATING NORTH AND SOUTH WITH SOME COOLING.  THE FRONT
WILL BE FIGHTING THE FLOW ALOFT AND THE AMOUNT OF COOLING IS IN
QUESTION.  OVERALL MODELS ARE IN FAIR AGREEMENT THROUGH THE MID TERM
AND EXTENDED FORECAST WITH THE GREATEST MODEL SPREAD TO THE NORTH
OVER CANADA...ESPECIALLY IN THE HUDSON BAY AREA.

&&

.AVIATION.../06Z ISSUANCE/

THE SECOND PORTION OF AN UPPER TROUGH WILL MOVE ACROSS WESTERN
WYOMING THIS MORNING AND INTO THE HIGH PLAINS BY 00Z MONDAY.
SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS WILL CONTINUE ACROSS
MUCH OF THE AREA AHEAD OF THE TROUGH.  THIS COVERAGE WILL BE MOST
NUMEROUS ACROSS THE NORTH...ACROSS YELLOWSTONE NATIONAL PARK TO
VCNTY COD-BYG AND NORTH.  SNOW LEVELS WILL ALSO LOWER TO 9-10KFT IN
THIS AREA BY SUNRISE WITH FQT MTN OBSCURATIONS AND AREAS OF
MVFR CONDITIONS.  THE OTHER AREA OF MORE ORGANIZED SHRA/ISOLD TSRA
COVERAGE IS EXPECTED ACROSS THE SOUTH OR VCNTY AND SOUTH OF A
KRKS-KCPR LINE THROUGH THIS MORNING.  CONDITIONS WILL IMPROVE WEST TO
EAST THROUGH THE AFTERNOON AND EVENING WITH PATCHY FOG DEVELOPING
WHERE BETTER RAINS HAVE FALLEN...ESPECIALLY ACROSS THE WESTERN
VALLEYS AND THE NORTHERN BASINS.

&&

.FIRE WEATHER...

AN EVOLVING LARGE UPPER LEVEL TROUGH WITH SEVERAL EMBEDDED
DISTURBANCES WILL PUSH ACROSS THE FORECAST AREA THROUGH SUNDAY AND
PART OF MONDAY. THIS SYSTEM WILL DESTABILIZE THE ATMOSPHERE AND PUSH
A FEW COLD FRONTS SOUTH ACROSS NORTH AND CENTRAL WYOMING THIS
AFTERNOON...AGAIN SUNDAY MORNING...AND FINALLY MONDAY AFTERNOON.
TODAY`S FRONT WILL BE THE FOCUS FOR STRONGER THUNDERSTORMS...
PRIMARILY NEAR AND NORTH OF A DUBOIS TO WORLAND TO GILLETTE LINE.
THESE STORMS WILL BE MOVING QUITE FAST AT AROUND 35 TO 40 KTS...WITH
SOME OF THESE STORMS CAPABLE OF MARGINALLY SEVERE HAIL AND WIND
GUSTS. SOUTH OF THE FRONT(S)...WEST TO WEST SOUTHWEST WINDS AT 20-25
MPH WITH GUSTS TO 40 MPH WILL BE POSSIBLE ALONG WITH MINIMUM RH
VALUES OF AROUND 20 PERCENT. THIS TOGETHER WITH ISOLATED TO WIDELY
SCT THUNDERSTORMS AND ERRATIC OUTFLOW WIND GUSTS NEAR 45KTS WILL
BRING ENHANCED FIRE DANGER TO THIS REGION FOR A FEW HOURS.

&&

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

$$

SHORT TERM...BRAUN
LONG TERM...C.BAKER
AVIATION...AEM
FIRE WEATHER...BRAUN








000
FXUS65 KRIW 310558
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
1155 PM MDT SAT AUG 30 2014

.SHORT TERM...TONIGHT THROUGH SUNDAY (ISSUED AT 222 PM MDT)

PROGRESSIVE EVOLVING UPR PATTERN WITH BROADENING TROF ACROSS THE WRN
CONUS...SW FLOW OVERHEAD WY...AND SW RIDGING OVR THE PLAINS. FIRST
EMBEDDED SW WITHIN THE TROF IS HEADING INTO THE WRN/NWRN PORTIONS OF
THE STATE THIS MORNING...AND WILL CONTINUE TO EXPAND ACROSS WY
THROUGHOUT THE DAY AND NIGHT PERIODS. AT THE SFC...DEVELOPING LOW
PRESSURE OVR THE BIG HORN BASIN...WITH WARM FRONT EXTENDING OF TO
THE E/SE...AND COLD FRONT(S) OFF TO THE N/NW FROM THIS LOW.

TODAY/TONIGHT...THE PROGRESSIVE NATURE OF THE UPR LVLS WILL CONTINUE
TO SPREAD STRONGER UPR LVL FLOW OVERHEAD RESULTING IN INCREASED NET
UPWARD LIFT THRU TODAY AND OVERNIGHT. THIS WILL CONTINUE TO GREATLY
IMPROVE CONVECTIVE CHANCES AND GROWTH POTENTIAL TODAY AND INTO THE
EVENING PERIOD. A FEW STRONG/MARGINALLY SVR STORMS EXPECTED WITH ML
CAPE RANGING FROM 500 TO 1000 J/KG AND DEEP SHEAR OF 40 TO 50 KTS
THIS AFTERNOON OVER THE NORTHERN ZONES. STRONGER STORMS WILL BE
CHARACTERIZED AS FAST MOVING AT 30 TO 40 KTS...WITH HAIL AND STRONG
GUSTY WINDS APPROACHING SEVERE LEVELS FOR A FEW HOURS THIS
AFTERNOON. ELSEWHERE...STORM WILL HAVE STRONG GUSTY WINDS WITH BRIEF
HEAVY RAIN AND SMALL HAIL. SHEAR TODAY IS PRIMARILY AVAILABLE IN THE
FORM OF SPEED SHEAR W/ HEIGHT...WITH INCREASING UNIDIRECTIONAL SW
FLOW ACROSS MUCH OF THE CWA. THIS WILL ALSO LEND ITSELF TO AMBIENT
WEST TO SOUTHWEST WINDS BLOWING 20 PLUS MPH TO BEGIN WITH.
OVERALL...SIGNIFICANT HYDRO POTENTIAL DOES NOT LOOK TO BE AN ISSUE
AT THIS TIME WITH THESE FAST MOVING STORMS...EXCEPT IN THE CASE OF A
TRAINING SITUATION. CONVECTIVE SNOW SHOWERS WILL ALSO BE POSSIBLE
OVERNIGHT AND THROUGH THE DAY SUNDAY...FIRST STARTING OUR ABOVE
10500 FT THIS EVENING...AND DECREASING AROUND 9000 FT BY EVENING
SUNDAY.

SUNDAY...THE UPR TROF CONTINUES CROSSING/EXPANDING ACROSS THE STATE
FROM W TO E...WITH MUCH COOLER CONDITIONS FOR SURE BUT CONTINUED
GUSTY W TO WSW WINDS ACROSS THE SRN FA...AND GUSTY N TO NW WINDS
BEHIND THE FRONT...WITH ANOTHER SFC COLD FRONT POISED TO ENTER THE
STATE FROM THE NORTH THROUGH THE DAY. SHOWERS AND ISOLATED THUNDER
WILL BE RATHER PREVALENT ACROSS THE ENTIRE CWA FROM MORNING THROUGH
EARLY AFTERNOON BEFORE DECREASING FROM W TO E LATER IN THE DAY AND
EVENING. STRONGER STORMS WITH SMALL HAIL AND GUSTY WINDS WILL BE
MOST PROBABLY ACROSS NATRONA AND EASTERN FREMONT AND SWEETWATER
COUNTIES NEAR A FRONTAL BOUNDARY.

.LONG TERM...SUNDAY NIGHT THROUGH SATURDAY

SUNDAY NIGHT AN UPPER LEVEL LOW PRESSURE TROUGH WILL BE PASSING
THROUGH THE AREA SUPPORTING SOME SHOWERS AND ISOLATED
THUNDERSTORMS...MOST NUMEROUS OVER THE NORTHERN MOUNTAINS IN THE
EVENING.  SOME CONVECTION WILL LINGER THROUGH THE NIGHT.

MONDAY AND MONDAY NIGHT AS THE TROUGH CONTINUE TO MOVE EAST...
HIGH PRESSURE RIDGING WILL OCCUR OVER THE PACIFIC NORTHWEST.  SOME
SHOWERS MAY LINGER ACROSS THE WEST BUT THE MAIN TREND WILL BE FOR
DRYING WITH BREEZY TO WINDY CONDITIONS ACROSS THE SOUTH INTO
CENTRAL AREAS.

TUESDAY AND TUESDAY NIGHT DRY HIGH PRESSURE IS EXPECTED TO DOMINATE
THE WEATHER ACROSS THE AREA WITH INCREASING WEST TO SOUTHWEST WINDS
CENTRAL AND SOUTH WITH GENERAL WARMING.

WEDNESDAY AND WEDNESDAY NIGHT  SOME MID LEVEL CLOUDS ARE EXPECTED TO
MOVE UP FROM THE GREAT BASIN IN THE AFTERNOON...OTHERWISE THE DRY
HIGH PRESSURE IS EXPECTED TO CONTINUE TO DOMINATE THE WEATHER WITH
CONTINUED SOUTHWEST WINDS ACROSS THE CENTRAL AND SOUTH.

THURSDAY AND THURSDAY NIGHT  HIGH PRESSURE WILL SHIFT EAST WITH
INCREASING SOUTHWEST FLOW ALOFT BRINGING SOME PACIFIC MOISTURE ALOFT
OVER THE AREA.  SHOWERS ARE EXPECTED TO DEVELOP WITH ISOLATED
THUNDERSTORMS IN THE AFTERNOON...MOST NUMEROUS OVER THE WESTERN AND
CENTRAL MOUNTAINS.  INCREASED CLOUD COVER WILL BRING SOME COOLING.

FRIDAY AND FRIDAY NIGHT  SHOWERS AND ISOLATED THUNDERSTORMS ARE
EXPECTED TO INCREASE OVER THE AREA AS PACIFIC MOISTURE INCREASES IN
SOUTHWEST FLOW ALOFT.  A WEAK COLD FRONT WILL MOVE SLOWLY SOUTH FROM
MONTANA INTO NORTHERN WYOMING.

SATURDAY SOUTHWEST FLOW ALOFT WILL REMAIN IN PLACE OVER THE AREA
WITH A STREAM OF PACIFIC MOISTURE CONTINUING TO ADVECT INTO THE AREA
SUPPORTING SCATTERED SHOWERS AND SOME ISOLATED AFTERNOON
THUNDERSTORMS.  A FRONT IS EXPECTED TO HANG OUT ACROSS NORTHERN
WYOMING OSCILLATING NORTH AND SOUTH WITH SOME COOLING.  THE FRONT
WILL BE FIGHTING THE FLOW ALOFT AND THE AMOUNT OF COOLING IS IN
QUESTION.  OVERALL MODELS ARE IN FAIR AGREEMENT THROUGH THE MID TERM
AND EXTENDED FORECAST WITH THE GREATEST MODEL SPREAD TO THE NORTH
OVER CANADA...ESPECIALLY IN THE HUDSON BAY AREA.

&&

.AVIATION.../06Z ISSUANCE/

THE SECOND PORTION OF AN UPPER TROUGH WILL MOVE ACROSS WESTERN
WYOMING THIS MORNING AND INTO THE HIGH PLAINS BY 00Z MONDAY.
SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS WILL CONTINUE ACROSS
MUCH OF THE AREA AHEAD OF THE TROUGH.  THIS COVERAGE WILL BE MOST
NUMEROUS ACROSS THE NORTH...ACROSS YELLOWSTONE NATIONAL PARK TO
VCNTY COD-BYG AND NORTH.  SNOW LEVELS WILL ALSO LOWER TO 9-10KFT IN
THIS AREA BY SUNRISE WITH FQT MTN OBSCURATIONS AND AREAS OF
MVFR CONDITIONS.  THE OTHER AREA OF MORE ORGANIZED SHRA/ISOLD TSRA
COVERAGE IS EXPECTED ACROSS THE SOUTH OR VCNTY AND SOUTH OF A
KRKS-KCPR LINE THROUGH THIS MORNING.  CONDITIONS WILL IMPROVE WEST TO
EAST THROUGH THE AFTERNOON AND EVENING WITH PATCHY FOG DEVELOPING
WHERE BETTER RAINS HAVE FALLEN...ESPECIALLY ACROSS THE WESTERN
VALLEYS AND THE NORTHERN BASINS.

&&

.FIRE WEATHER...

AN EVOLVING LARGE UPPER LEVEL TROUGH WITH SEVERAL EMBEDDED
DISTURBANCES WILL PUSH ACROSS THE FORECAST AREA THROUGH SUNDAY AND
PART OF MONDAY. THIS SYSTEM WILL DESTABILIZE THE ATMOSPHERE AND PUSH
A FEW COLD FRONTS SOUTH ACROSS NORTH AND CENTRAL WYOMING THIS
AFTERNOON...AGAIN SUNDAY MORNING...AND FINALLY MONDAY AFTERNOON.
TODAY`S FRONT WILL BE THE FOCUS FOR STRONGER THUNDERSTORMS...
PRIMARILY NEAR AND NORTH OF A DUBOIS TO WORLAND TO GILLETTE LINE.
THESE STORMS WILL BE MOVING QUITE FAST AT AROUND 35 TO 40 KTS...WITH
SOME OF THESE STORMS CAPABLE OF MARGINALLY SEVERE HAIL AND WIND
GUSTS. SOUTH OF THE FRONT(S)...WEST TO WEST SOUTHWEST WINDS AT 20-25
MPH WITH GUSTS TO 40 MPH WILL BE POSSIBLE ALONG WITH MINIMUM RH
VALUES OF AROUND 20 PERCENT. THIS TOGETHER WITH ISOLATED TO WIDELY
SCT THUNDERSTORMS AND ERRATIC OUTFLOW WIND GUSTS NEAR 45KTS WILL
BRING ENHANCED FIRE DANGER TO THIS REGION FOR A FEW HOURS.

&&

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

$$

SHORT TERM...BRAUN
LONG TERM...C.BAKER
AVIATION...AEM
FIRE WEATHER...BRAUN








000
FXUS63 KUNR 310520
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
1120 PM MDT SAT AUG 30 2014

.SHORT TERM...THIS EVENING THROUGH SUNDAY NIGHT
ISSUED AT 312 PM MDT SAT AUG 30 2014

CURRENT SURFACE ANALYSIS SHOWS LOW PRESSURE OVER FAR NORTHEAST
WY...WITH COLD FRONT FROM FAR EASTERN MT INTO CENTRAL WY. UPPER
LEVEL ANALYSIS SHOWS WEAK RIDGING OVER THE DAKOTAS WITH BROAD TROF
COVERING MUCH OF THE WESTERN CONUS. NUMEROUS SHORTWAVES ARE NOTED
WITHIN THE TROF...WITH THEM CURRENTLY OVER NORTHEAST MT...CENTRAL
WY AND SOUTH CENTRAL MT...AND EASTERN OR AND SOUTHWESTERN ID.
SKIES ARE VARIABLY CLOUDY OVER NORTHEAST WY...WITH MOSTLY SUNNY
SKIES TO THE EAST. ISOLATED SHOWERS AND STORMS HAVE STARTED TO
DEVELOP OVER NORTHEAST WY IN THE VICINITY OF THE COLD FRONT. TEMPS
RANGE FROM THE UPPER 70S TO UPPER 80S ACROSS THE AREA. WINDS ARE
SOUTH-SOUTHEAST...BREEZY AT TIMES OVER MOST OF THE AREA...EXCEPT
FOR NORTHWESTERLY WINDS OVER CAMPBELL CO BEHIND THE FRONT.

CHANCES FOR SHOWERS AND STORMS WILL INCREASE THROUGH THE LATE
AFTERNOON AND EVENING FROM WEST TO EAST...ESPECIALLY ACROSS NORTHERN
PORTIONS OF THE CWA...AS THE SHORTWAVE OVER WY MOVES EAST-NORTHEAST
THROUGH THE REGION. THE STRONGEST FORCING WITH THE WAVE MOVES ACROSS
NORTHERN PORTIONS OF THE CWA AND POINTS FURTHER TO THE NORTH THIS
EVENING. THIS IS WHERE THE BEST CHANCES FOR PCPN WILL BE...AS WELL
AS THE RISK FOR ISOLATED SEVERE STORMS. CHANCES FOR PCPN AND SEVERE
WEATHER WILL DECREASE FURTHER SOUTH ACROSS THE CWA...WITH ONLY
SLIGHT CHANCES FOR A SHOWER OR STORM OVER FAR SOUTHERN SD THROUGH
THE EVENING. THINKING FROM PREVIOUS FORECAST GENERALLY HOLDS...WITH
THE BEST THREAT FOR STRONG TO SEVERE STORMS GENERALLY NEAR OR NORTH
OF A LINE FROM GILLETTE TO NEAR SPEARFISH...TO FAITH AND DUPREE.
HOWEVER...THE SLIGHTLY LATER TIMING OF THIS WAVE ADDS SOME
UNCERTAINTY TO THE RISK...ESPECIALLY OVER EASTERN PORTIONS OF THE
RISK AREA LATER ON. INSTABILITY IS FAIRLY STRONG ACROSS THE
AREA...ESPECIALLY TO THE NORTH AND EAST OF THE BLACK HILLS LATE THIS
AFTERNOON INTO THE EVENING. SHEAR WILL ALSO BE STRONGEST TO THE
NORTH AND EAST OF THE SURFACE LOW AS IT SLOWLY TRACKS FROM NORTHEAST
WY THROUGH WESTERN SD THIS EVENING. THE MAIN THREATS FROM ANY SEVERE
STORMS WILL BE LARGE HAIL AND STRONG WIND GUSTS...BUT AN ISOLATED
TORNADO CANNOT BE TOTALLY RULED OUT OVER EXTREME NORTHEAST WY INTO
NORTHWEST SD. LOCALLY HEAVY RAINFALL IS ALSO POSSIBLE...ESPECIALLY
ACROSS FAR NORTHWESTERN SD. MOST OF THE ACTIVITY WITH THIS WAVE WILL
EXIT EAST OF THE CWA AROUND 06Z...WITH LINGERING ISOLATED LIGHTER
ACTIVITY POSSIBLE INTO THE OVERNIGHT OVER THE CWA. GUSTY NORTHWEST
WINDS WILL DEVELOP ACROSS THE WESTERN SD PLAINS DURING THE
EVENING...AFTER THE FRONT PASSES. THE STRONGEST WINDS WILL GENERALLY
BE IN THE RAPID CITY AREA...AS WELL AS THE NEARBY PLAINS TO THE
NORTH AND EAST. WINDS WILL GRADUALLY DECREASE AFTER MIDNIGHT.

THE NEXT SHORTWAVE OVER OR/ID WILL APPROACH OUR WESTERN ZONES BY
EARLY SUNDAY MORNING...WITH THIS ONE TRACKING A BIT FURTHER SOUTH
ACROSS THE CWA DURING THE DAY. THIS SYSTEM SHOULD BRING A MORE
WIDESPREAD COVERAGE OF PCPN ACROSS THE AREA...WITH COLDER AIR ALOFT
KEEPING THE ATMOSPHERE UNSTABLE. SHOWERS ARE LIKELY ACROSS THE BLACK
HILLS AREA...WITH A PRETTY GOOD CHANCE FOR SHOWERS ACROSS THE REST
OF THE CWA DURING THE DAY...ESPECIALLY IN THE LATE MORNING AND
AFTERNOON. A FEW THUNDERSTORMS ARE POSSIBLE...BUT CLOUD COVER AND
COOLER AIR WILL HELP TO KEEP CAPE VALUES RATHER LOW. HIGHS WILL ONLY
BE IN THE 70S ACROSS THE SD PLAINS...WITH 60S OVER THE BLACK HILLS
AND NORTHEAST WY. SHOWERS WILL EXIT EASTERN AREAS IN THE EVENING
WITH A COOL NIGHT ON TAP FOR MOST AREAS. YET ANOTHER DISTURBANCE IS
PROGGED TO APPROACH WESTERN PORTIONS OF THE AREA LATE SUNDAY NIGHT
OR MONDAY MORNING.

&&

.LONG TERM...MONDAY THROUGH SATURDAY
ISSUED AT 312 PM MDT SAT AUG 30 2014

SHORTWAVE EMBEDDED IN CYCLONIC FLOW WILL BRING CONTINUED CHANCES
FOR -SHRA/-TSRA MONDAY...BUT COVERAGE SHOULD BE LOWER THAN SUNDAY
ON THE PLAINS. UPPER TROUGH WILL SHARPEN OVER THE PACIFIC
NORTHWEST TUESDAY/WEDNESDAY BRINGING A FLAT UPPER RIDGE/THERMAL
RIDGE OVER THE CWA RESULTING IN DRIER/WARMER WEATHER. LONG TERM
GUIDANCE NOW SHOWING WEST/NORTHWEST FLOW ALOFT AND A SERIES OF
FRONTS DANCING ACROSS THE REGION FOR THURSDAY THROUGH SATURDAY.
RESULT WILL BE CHANCES FOR -SHRA/-TSRA ALONG WITH COOLER
TEMPERATURES FOR THE END OF NEXT WEEK.

&&

.AVIATION...FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT
ISSUED AT 1115 PM MDT SAT AUG 30 2014

SCATTERED SHOWERS AND A FEW THUNDERSTORMS WILL CROSS WESTERN SOUTH
DAKOTA TONIGHT. ADDITIONAL SHOWERS AND THUNDERSTORMS WILL DEVELOP
OVER NORTHEASTERN WYOMING LATE SUNDAY MORNING AND WILL INCREASE IN
COVERAGE AS THE PRECIPTIATION SPREADS NORTHEASTWARD DURING THE AFTERNOON.
MAINLY VFR CIGS ARE EXPECTED...ALTHOUGH AREAS OF MVFR CONDITIONS
ARE POSSIBLE WITH THE RAIN SHOWERS AND THUNDERSTORMS. THE SHOWERS
AND THUNDERSTORMS WILL END LATE SUNDAY EVENING.

&&

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

$$

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






000
FXUS65 KCYS 310427
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
1027 PM MDT SAT AUG 30 2014

.UPDATE...
ISSUED AT 826 PM MDT SAT AUG 30 2014

CONVECTION IS STARTING TO WIND DOWN ACROSS THE CWA THIS EVE. WIND
GUSTS IN EXCESS OF 45 MPH WERE COMMON WITH LARGE SFC TEMP-DEWPOINT
SPREADS AND RESULTANT INVERTED-V SOUNDING PROFILES. WE HAD ONE
STORM KICK OUT SOME INTENSE OUTFLOW AS IT MOVED OVER CYS AROUND
500 PM WITH GUSTS TO 60 MPH REPORTED AT THE INTERSTATE 80 PORT OF
ENTRY EAST OF CHEYENNE. MORE WIDESPREAD PCPN AND A GENERAL LOSS OF
DIURNAL HEATING HAS STABILIZED THINGS FOR THE REST OF THE NIGHT SO
DO NOT EXPECT ANYMORE BIG WIND GUSTS. SHOULD ALSO SEE LESS IN THE
WAY OF LIGHTNING STRIKES WITH MAINLY SHOWERS OVERNIGHT. WATER
VAPOR SATELLITE SHOWS THE LEAD SHORTWAVE MOVING ACROSS FAR EASTERN
WY AS OF 02Z. THIS IS RESPONSIBLE FOR ONGOING NUMEROUS SHOWERS AND
WEAK TSTMS OVER THE PANHANDLE. CLEARING/SUBSIDENCE IN THE WAKE OF
THIS FEATURE SHOULD SHUT PCPN OFF FOR A LITTLE WHILE. WENT AHEAD
AND KEPT ISOLATED POPS IN FOR MOST OF THE NIGHT AS THE MAIN COLD
FRONT IS STILL HANGING BACK OVER CENTRAL WY. FROPA OVERNIGHT AND
LARGER SCALE ASCENT ASSOCIATED WITH A LARGER PIECE OF SHORTWAVE
ENERGY CURRENTLY UPSTREAM WILL RESULT IN AN INCREASE IN SHOWERS
FROM WEST TO EAST BY DAYBREAK SUN. UPDATED POPS AND CLOUD TRENDS
BASED ON CURRENT RADAR/SATELLITE IMAGERY. OTHERWISE THE INHERITED
FCST IS IN GOOD SHAPE TONIGHT BASED ON OBS AND NEAR TERM HIGH-RES
MODELS.

&&

.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 418 PM MDT SAT AUG 30 2014

WATER VAPOR IMAGERY FROM THIS AFTERNOON SHOWS THE LEAD IMPULSE IN
A QUASI-ZONAL FLOW PATTERN ENTERING SOUTHWEST WYOMING THIS
AFTERNOON...WITH SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS
DEVELOPING OVER THE CWA OUT AHEAD OF THIS WAVE. THE FOCUS FOR
CONVECTIVE INITIATION WAS OVER THE MOUNTAINS EARLY THIS AFTERNOON...AND
ALONG VARIOUS BOUNDARIES THAT SET UP ALONG LARAMIE AND CONVERSE
COUNTIES THIS AFTERNOON. MLCAPES ARE UP TO 500 J/KG ACROSS THE
PLAINS ACCORDING TO SPC MESOANALYSIS...WITH DEEP LAYER SHEAR 20
KTS OR LESS. THEREFORE...EXPECT CONVECTION TO CONTINUE THROUGH
THIS EVENING INCLUDING LOCATIONS ACROSS THE NEB PANHANDLE AS THE
UPPER WAVE APPROACHES. BUT WITH LACK OF SIGNIFICANT INSTABILITY
AND SHEAR...STORMS SHOULD REMAIN RELATIVELY WEAK WITH GUSTY AND
ERRATIC WINDS THE MAIN IMPACT. WITH MODERATE SOUTHWEST WINDS ALREADY
IN PLACE OVER MUCH OF THE FORECAST AREA DUE TO 3MB/3HR PRESSURE
FALLS OVER THE HIGH PLAINS...TSTORM DOWNDRAFTS COULD AUGMENT THE
CURRENT WINDS SPEEDS...WITH GUSTS OF 50 TO 55 MPH GUSTS POSSIBLE
FROM ANY STORMS.

A COLD FRONT WILL TRY TO MOVE SOUTH ACROSS THE CWA THIS
EVENING...BUT LOOKS TO STALL NW-SE ACROSS CONVERSE COUNTY INTO THE
NORTHERN NEB PANHANDLE TONIGHT THRU EARLY SUNDAY. THIS SHOULD
MAINTAIN SHOWER/TSTORM DEVELOPMENT OVER THIS AREA THIS EVENING AND
AS THE UPPER WAVE MOVES ACROSS THE FORECAST AREA. A SECOND AND
STRONGER PV ANOMALY WILL APPROACH FROM THE WEST EARLY SUNDAY
MORNING...WITH A RE-INTENSIFICATION OF CONVECTION EXPECTED THROUGH
THE MORNING IN RESPONSE TO THE INCREASED UPPER FORCING. THE LEFT
EXIT REGION OF A 105 KT JET WILL MOVE OVERHEAD BY THE AFTERNOON AS
WELL...WITH THE SFC FRONT MAKING A RUN SOUTH ACROSS THE PLAINS
THROUGH THE LATE AFTERNOON. SO ANTICIPATE A GOOD COVERAGE OF
SHOWERS AND STORMS THROUGH THE DAY WITH THE COMBINATION OF SFC AND
UPPER FORCING...AND INCREASED POPS ANOTHER 5 TO 10 PERCENT FROM
THE PREVIOUS FORECAST. LOOKING AT GUSTY WINDS...SMALL HAIL AND
BRIEF MODERATE RAIN TO BE THE MAIN THREATS AS INSTABILITY VALUES
ARE PROGGED TO BE BETWEEN 500 AND 1000 J/KG THRU THE AFTERNOON
WITH ROUGHLY 30 KTS OF SHEAR OVERHEAD. MUCH DRIER AIR WILL MOVE IN
SUNDAY EVENING WITH STORMS PUSHING TO THE EAST. ANOTHER
COLD FRONT WILL APPROACH FROM THE NORTH MONDAY AFTERNOON AND
SHOULD INITIATE A FEW SHOWERS AND T-STORMS ACROSS THE PLAINS IN
THE AFTERNOON. OTHERWISE...SUNDAY AND MONDAY LOOK TO BE MUCH
COOLER THAN TODAY WITH THE PASSAGE OF THESE COLD FRONTS.

.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 418 PM MDT SAT AUG 30 2014

THE LONGWAVE UPPER TROUGH SHOULD CONTINUE SHIFTING EAST OF OUR
REGION TUESDAY WITH A DEEPLY DRY AIRMASS IN PLACE WITH MOST OF ANY
STRONGER SHORTWAVE ENERGY COMING DOWN THE NORTHWESTERLY FLOW ALOFT
REMAINING TO THE NORTH THROUGH AT LEAST WEDNESDAY. THIS PATTERN
WILL KEEP OUR AREA DRY THROUGH WEDNESDAY...POSSIBLY SIGNIFICANTLY
DRY WITH GFS SUGGESTING BOUNDARY LAYER DEWPOINTS GETTING INTO THE
UPPER TEENS FOR SOME AREAS OUT IN THE HIGHER TERRAIN AND WESTERN
ZONES TUESDAY INTO WEDNESDAY. SYNOPTIC SCALE PATTERN INDICATED IN
THE GFS/ECMWF SUGGESTIVE THAT WESTERLY/SOUTHWESTERLY DOWNSLOPE
WINDS WILL COME UP A BIT TUESDAY INTO WEDNESDAY AND WE ARE
FORECASTING THEM A LITTLE HIGHER THAN WHAT THE RAW MODEL GUIDANCE
SUGGESTS MIDWEEK WITH DEWPOINTS A FEW DEGREES DRIER AS WELL
(PLEASE REFER TO FIRE WEATHER SECTION OF THE DISCUSSION FOR MORE
INFORMATION ON POTENTIAL IMPACTS). OTHERWISE...GFS AND NOW THE ECMWF
BOTH IN FAIR AGREEMENT DEEPENING AN UPPER TROUGH ALONG THE WEST
COAST THURSDAY INTO FRIDAY...INDUCING A MORE SOUTHWESTERLY
MID/UPPER FLOW ACROSS OUR AREA GOING INTO LATE WEEK. THIS
PATTERN...IF IT DEVELOPS...SHOULD HELP US TAP INTO ANOTHER ROUND OF
PACIFIC MOISTURE COMING UP THROUGH THE 4 CORNERS REGION INTO
SOUTHERN WYOMING AND WESTERN NEBRASKA...SO WE CONTINUED PREVIOUS
FORECAST TREND OF BRINGING SLIGHT CHANCE TO LOCALLY CHANCE POPS
(HIGHER TERRAIN) FOR SHOWERS/THUNDERSTORMS BY LATE IN THE NEXT
WEEK.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY EVENING)
ISSUED AT 1025 PM MDT SAT AUG 30 2014

COLD FRONT CONTINUES TO SLOWLY MOVE INTO THE AREA LATE THIS
EVENING. STILL KICKING OFF SOME THUNDERSTORMS OVER THE MOUNTAINS
TO THE WEST...BUT ELSEWHERE...RADAR SHOWING CONVECTION COMING TO
AN END. VFR CONDITIONS EXPECTED AT ALL TAF SITES OVERNIGHT. RETURN
OF GUSTY WINDS AND ISOLATED THUNDERSTORMS FOR SUNDAY AFTERNOON.

&&

.FIRE WEATHER...
ISSUED AT 418 PM MDT SAT AUG 30 2014

WIDELY SCATTERED SHOWERS AND THUNDERSTORMS WILL
CONTINUE THIS AFTERNOON AND EVENING FOR MUCH OF THE DISTRICT AS A
STRONG WEATHER DISTURBANCE MOVES THROUGH THE AREA. A WEAK COLD
FRONT WILL MOVE SOUTH ACROSS ZONES 301 AND 311...AND WILL STALL
ACROSS THIS AREA TONIGHT THROUGH EARLY SUNDAY. GUSTY WEST TO
SOUTHWEST WINDS OCCURRING THIS AFTERNOON SOUTH OF THE FRONT WILL
EASE TONIGHT...AND WILL INCREASE ONCE AGAIN THROUGH SUNDAY MORNING
WITH GUSTS BETWEEN 30 AND 40 MPH EXPECTED ALONG AND WEST OF THE
LARAMIE RANGE THROUGH THE AFTERNOON. WINDS ACROSS THE PLAINS WILL
BE GUSTING 25 TO 30 MPH IN THE LATE MORNING UNTIL THE FRONT
FINALLY PUSHES SOUTH ACROSS THIS AREA BETWEEN 1200 AND 1900.
SHOWERS AND T-STORMS WILL OCCUR ALONG THE FRONT AND AS ANOTHER
STRONG WEATHER DISTURBANCE MOVES OVER THE AREA THROUGH SUNDAY.
DRIER CONDITIONS WILL DEVELOP BY MIDDLE OF NEXT WEEK WHILE GUSTY
WEST WINDS CONTINUE IN AREAS ALONG AND WEST OF THE LARAMIE RANGE.
LOOKING FOR FIRE WEATHER CONCERNS TO INCREASE ACROSS THIS AREA AS
A RESULT.

&&

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

$$

UPDATE...HAMMER
SHORT TERM...RJM
LONG TERM...GARMON
AVIATION...CLAYCOMB
FIRE WEATHER...RJM






000
FXUS65 KCYS 310427
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
1027 PM MDT SAT AUG 30 2014

.UPDATE...
ISSUED AT 826 PM MDT SAT AUG 30 2014

CONVECTION IS STARTING TO WIND DOWN ACROSS THE CWA THIS EVE. WIND
GUSTS IN EXCESS OF 45 MPH WERE COMMON WITH LARGE SFC TEMP-DEWPOINT
SPREADS AND RESULTANT INVERTED-V SOUNDING PROFILES. WE HAD ONE
STORM KICK OUT SOME INTENSE OUTFLOW AS IT MOVED OVER CYS AROUND
500 PM WITH GUSTS TO 60 MPH REPORTED AT THE INTERSTATE 80 PORT OF
ENTRY EAST OF CHEYENNE. MORE WIDESPREAD PCPN AND A GENERAL LOSS OF
DIURNAL HEATING HAS STABILIZED THINGS FOR THE REST OF THE NIGHT SO
DO NOT EXPECT ANYMORE BIG WIND GUSTS. SHOULD ALSO SEE LESS IN THE
WAY OF LIGHTNING STRIKES WITH MAINLY SHOWERS OVERNIGHT. WATER
VAPOR SATELLITE SHOWS THE LEAD SHORTWAVE MOVING ACROSS FAR EASTERN
WY AS OF 02Z. THIS IS RESPONSIBLE FOR ONGOING NUMEROUS SHOWERS AND
WEAK TSTMS OVER THE PANHANDLE. CLEARING/SUBSIDENCE IN THE WAKE OF
THIS FEATURE SHOULD SHUT PCPN OFF FOR A LITTLE WHILE. WENT AHEAD
AND KEPT ISOLATED POPS IN FOR MOST OF THE NIGHT AS THE MAIN COLD
FRONT IS STILL HANGING BACK OVER CENTRAL WY. FROPA OVERNIGHT AND
LARGER SCALE ASCENT ASSOCIATED WITH A LARGER PIECE OF SHORTWAVE
ENERGY CURRENTLY UPSTREAM WILL RESULT IN AN INCREASE IN SHOWERS
FROM WEST TO EAST BY DAYBREAK SUN. UPDATED POPS AND CLOUD TRENDS
BASED ON CURRENT RADAR/SATELLITE IMAGERY. OTHERWISE THE INHERITED
FCST IS IN GOOD SHAPE TONIGHT BASED ON OBS AND NEAR TERM HIGH-RES
MODELS.

&&

.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 418 PM MDT SAT AUG 30 2014

WATER VAPOR IMAGERY FROM THIS AFTERNOON SHOWS THE LEAD IMPULSE IN
A QUASI-ZONAL FLOW PATTERN ENTERING SOUTHWEST WYOMING THIS
AFTERNOON...WITH SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS
DEVELOPING OVER THE CWA OUT AHEAD OF THIS WAVE. THE FOCUS FOR
CONVECTIVE INITIATION WAS OVER THE MOUNTAINS EARLY THIS AFTERNOON...AND
ALONG VARIOUS BOUNDARIES THAT SET UP ALONG LARAMIE AND CONVERSE
COUNTIES THIS AFTERNOON. MLCAPES ARE UP TO 500 J/KG ACROSS THE
PLAINS ACCORDING TO SPC MESOANALYSIS...WITH DEEP LAYER SHEAR 20
KTS OR LESS. THEREFORE...EXPECT CONVECTION TO CONTINUE THROUGH
THIS EVENING INCLUDING LOCATIONS ACROSS THE NEB PANHANDLE AS THE
UPPER WAVE APPROACHES. BUT WITH LACK OF SIGNIFICANT INSTABILITY
AND SHEAR...STORMS SHOULD REMAIN RELATIVELY WEAK WITH GUSTY AND
ERRATIC WINDS THE MAIN IMPACT. WITH MODERATE SOUTHWEST WINDS ALREADY
IN PLACE OVER MUCH OF THE FORECAST AREA DUE TO 3MB/3HR PRESSURE
FALLS OVER THE HIGH PLAINS...TSTORM DOWNDRAFTS COULD AUGMENT THE
CURRENT WINDS SPEEDS...WITH GUSTS OF 50 TO 55 MPH GUSTS POSSIBLE
FROM ANY STORMS.

A COLD FRONT WILL TRY TO MOVE SOUTH ACROSS THE CWA THIS
EVENING...BUT LOOKS TO STALL NW-SE ACROSS CONVERSE COUNTY INTO THE
NORTHERN NEB PANHANDLE TONIGHT THRU EARLY SUNDAY. THIS SHOULD
MAINTAIN SHOWER/TSTORM DEVELOPMENT OVER THIS AREA THIS EVENING AND
AS THE UPPER WAVE MOVES ACROSS THE FORECAST AREA. A SECOND AND
STRONGER PV ANOMALY WILL APPROACH FROM THE WEST EARLY SUNDAY
MORNING...WITH A RE-INTENSIFICATION OF CONVECTION EXPECTED THROUGH
THE MORNING IN RESPONSE TO THE INCREASED UPPER FORCING. THE LEFT
EXIT REGION OF A 105 KT JET WILL MOVE OVERHEAD BY THE AFTERNOON AS
WELL...WITH THE SFC FRONT MAKING A RUN SOUTH ACROSS THE PLAINS
THROUGH THE LATE AFTERNOON. SO ANTICIPATE A GOOD COVERAGE OF
SHOWERS AND STORMS THROUGH THE DAY WITH THE COMBINATION OF SFC AND
UPPER FORCING...AND INCREASED POPS ANOTHER 5 TO 10 PERCENT FROM
THE PREVIOUS FORECAST. LOOKING AT GUSTY WINDS...SMALL HAIL AND
BRIEF MODERATE RAIN TO BE THE MAIN THREATS AS INSTABILITY VALUES
ARE PROGGED TO BE BETWEEN 500 AND 1000 J/KG THRU THE AFTERNOON
WITH ROUGHLY 30 KTS OF SHEAR OVERHEAD. MUCH DRIER AIR WILL MOVE IN
SUNDAY EVENING WITH STORMS PUSHING TO THE EAST. ANOTHER
COLD FRONT WILL APPROACH FROM THE NORTH MONDAY AFTERNOON AND
SHOULD INITIATE A FEW SHOWERS AND T-STORMS ACROSS THE PLAINS IN
THE AFTERNOON. OTHERWISE...SUNDAY AND MONDAY LOOK TO BE MUCH
COOLER THAN TODAY WITH THE PASSAGE OF THESE COLD FRONTS.

.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 418 PM MDT SAT AUG 30 2014

THE LONGWAVE UPPER TROUGH SHOULD CONTINUE SHIFTING EAST OF OUR
REGION TUESDAY WITH A DEEPLY DRY AIRMASS IN PLACE WITH MOST OF ANY
STRONGER SHORTWAVE ENERGY COMING DOWN THE NORTHWESTERLY FLOW ALOFT
REMAINING TO THE NORTH THROUGH AT LEAST WEDNESDAY. THIS PATTERN
WILL KEEP OUR AREA DRY THROUGH WEDNESDAY...POSSIBLY SIGNIFICANTLY
DRY WITH GFS SUGGESTING BOUNDARY LAYER DEWPOINTS GETTING INTO THE
UPPER TEENS FOR SOME AREAS OUT IN THE HIGHER TERRAIN AND WESTERN
ZONES TUESDAY INTO WEDNESDAY. SYNOPTIC SCALE PATTERN INDICATED IN
THE GFS/ECMWF SUGGESTIVE THAT WESTERLY/SOUTHWESTERLY DOWNSLOPE
WINDS WILL COME UP A BIT TUESDAY INTO WEDNESDAY AND WE ARE
FORECASTING THEM A LITTLE HIGHER THAN WHAT THE RAW MODEL GUIDANCE
SUGGESTS MIDWEEK WITH DEWPOINTS A FEW DEGREES DRIER AS WELL
(PLEASE REFER TO FIRE WEATHER SECTION OF THE DISCUSSION FOR MORE
INFORMATION ON POTENTIAL IMPACTS). OTHERWISE...GFS AND NOW THE ECMWF
BOTH IN FAIR AGREEMENT DEEPENING AN UPPER TROUGH ALONG THE WEST
COAST THURSDAY INTO FRIDAY...INDUCING A MORE SOUTHWESTERLY
MID/UPPER FLOW ACROSS OUR AREA GOING INTO LATE WEEK. THIS
PATTERN...IF IT DEVELOPS...SHOULD HELP US TAP INTO ANOTHER ROUND OF
PACIFIC MOISTURE COMING UP THROUGH THE 4 CORNERS REGION INTO
SOUTHERN WYOMING AND WESTERN NEBRASKA...SO WE CONTINUED PREVIOUS
FORECAST TREND OF BRINGING SLIGHT CHANCE TO LOCALLY CHANCE POPS
(HIGHER TERRAIN) FOR SHOWERS/THUNDERSTORMS BY LATE IN THE NEXT
WEEK.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY EVENING)
ISSUED AT 1025 PM MDT SAT AUG 30 2014

COLD FRONT CONTINUES TO SLOWLY MOVE INTO THE AREA LATE THIS
EVENING. STILL KICKING OFF SOME THUNDERSTORMS OVER THE MOUNTAINS
TO THE WEST...BUT ELSEWHERE...RADAR SHOWING CONVECTION COMING TO
AN END. VFR CONDITIONS EXPECTED AT ALL TAF SITES OVERNIGHT. RETURN
OF GUSTY WINDS AND ISOLATED THUNDERSTORMS FOR SUNDAY AFTERNOON.

&&

.FIRE WEATHER...
ISSUED AT 418 PM MDT SAT AUG 30 2014

WIDELY SCATTERED SHOWERS AND THUNDERSTORMS WILL
CONTINUE THIS AFTERNOON AND EVENING FOR MUCH OF THE DISTRICT AS A
STRONG WEATHER DISTURBANCE MOVES THROUGH THE AREA. A WEAK COLD
FRONT WILL MOVE SOUTH ACROSS ZONES 301 AND 311...AND WILL STALL
ACROSS THIS AREA TONIGHT THROUGH EARLY SUNDAY. GUSTY WEST TO
SOUTHWEST WINDS OCCURRING THIS AFTERNOON SOUTH OF THE FRONT WILL
EASE TONIGHT...AND WILL INCREASE ONCE AGAIN THROUGH SUNDAY MORNING
WITH GUSTS BETWEEN 30 AND 40 MPH EXPECTED ALONG AND WEST OF THE
LARAMIE RANGE THROUGH THE AFTERNOON. WINDS ACROSS THE PLAINS WILL
BE GUSTING 25 TO 30 MPH IN THE LATE MORNING UNTIL THE FRONT
FINALLY PUSHES SOUTH ACROSS THIS AREA BETWEEN 1200 AND 1900.
SHOWERS AND T-STORMS WILL OCCUR ALONG THE FRONT AND AS ANOTHER
STRONG WEATHER DISTURBANCE MOVES OVER THE AREA THROUGH SUNDAY.
DRIER CONDITIONS WILL DEVELOP BY MIDDLE OF NEXT WEEK WHILE GUSTY
WEST WINDS CONTINUE IN AREAS ALONG AND WEST OF THE LARAMIE RANGE.
LOOKING FOR FIRE WEATHER CONCERNS TO INCREASE ACROSS THIS AREA AS
A RESULT.

&&

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

$$

UPDATE...HAMMER
SHORT TERM...RJM
LONG TERM...GARMON
AVIATION...CLAYCOMB
FIRE WEATHER...RJM







000
FXUS65 KCYS 310239
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
839 PM MDT SAT AUG 30 2014

.UPDATE...
ISSUED AT 826 PM MDT SAT AUG 30 2014

CONVECTION IS STARTING TO WIND DOWN ACROSS THE CWA THIS EVE. WIND
GUSTS IN EXCESS OF 45 MPH WERE COMMON WITH LARGE SFC TEMP-DEWPOINT
SPREADS AND RESULTANT INVERTED-V SOUNDING PROFILES. WE HAD ONE
STORM KICK OUT SOME INTENSE OUTFLOW AS IT MOVED OVER CYS AROUND
500 PM WITH GUSTS TO 60 MPH REPORTED AT THE INTERSTATE 80 PORT OF
ENTRY EAST OF CHEYENNE. MORE WIDESPREAD PCPN AND A GENERAL LOSS OF
DIURNAL HEATING HAS STABILIZED THINGS FOR THE REST OF THE NIGHT SO
DO NOT EXPECT ANYMORE BIG WIND GUSTS. SHOULD ALSO SEE LESS IN THE
WAY OF LIGHTNING STRIKES WITH MAINLY SHOWERS OVERNIGHT. WATER
VAPOR SATELLITE SHOWS THE LEAD SHORTWAVE MOVING ACROSS FAR EASTERN
WY AS OF 02Z. THIS IS RESPONSIBLE FOR ONGOING NUMEROUS SHOWERS AND
WEAK TSTMS OVER THE PANHANDLE. CLEARING/SUBSIDENCE IN THE WAKE OF
THIS FEATURE SHOULD SHUT PCPN OFF FOR A LITTLE WHILE. WENT AHEAD
AND KEPT ISOLATED POPS IN FOR MOST OF THE NIGHT AS THE MAIN COLD
FRONT IS STILL HANGING BACK OVER CENTRAL WY. FROPA OVERNIGHT AND
LARGER SCALE ASCENT ASSOCIATED WITH A LARGER PIECE OF SHORTWAVE
ENERGY CURRENTLY UPSTREAM WILL RESULT IN AN INCREASE IN SHOWERS
FROM WEST TO EAST BY DAYBREAK SUN. UPDATED POPS AND CLOUD TRENDS
BASED ON CURRENT RADAR/SATELLITE IMAGERY. OTHERWISE THE INHERITED
FCST IS IN GOOD SHAPE TONIGHT BASED ON OBS AND NEAR TERM HIGH-RES
MODELS.

&&

.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 418 PM MDT SAT AUG 30 2014

WATER VAPOR IMAGERY FROM THIS AFTERNOON SHOWS THE LEAD IMPULSE IN
A QUASI-ZONAL FLOW PATTERN ENTERING SOUTHWEST WYOMING THIS
AFTERNOON...WITH SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS
DEVELOPING OVER THE CWA OUT AHEAD OF THIS WAVE. THE FOCUS FOR
CONVECTIVE INITIATION WAS OVER THE MOUNTAINS EARLY THIS AFTERNOON...AND
ALONG VARIOUS BOUNDARIES THAT SET UP ALONG LARAMIE AND CONVERSE
COUNTIES THIS AFTERNOON. MLCAPES ARE UP TO 500 J/KG ACROSS THE
PLAINS ACCORDING TO SPC MESOANALYSIS...WITH DEEP LAYER SHEAR 20
KTS OR LESS. THEREFORE...EXPECT CONVECTION TO CONTINUE THROUGH
THIS EVENING INCLUDING LOCATIONS ACROSS THE NEB PANHANDLE AS THE
UPPER WAVE APPROACHES. BUT WITH LACK OF SIGNIFICANT INSTABILITY
AND SHEAR...STORMS SHOULD REMAIN RELATIVELY WEAK WITH GUSTY AND
ERRATIC WINDS THE MAIN IMPACT. WITH MODERATE SOUTHWEST WINDS ALREADY
IN PLACE OVER MUCH OF THE FORECAST AREA DUE TO 3MB/3HR PRESSURE
FALLS OVER THE HIGH PLAINS...TSTORM DOWNDRAFTS COULD AUGMENT THE
CURRENT WINDS SPEEDS...WITH GUSTS OF 50 TO 55 MPH GUSTS POSSIBLE
FROM ANY STORMS.

A COLD FRONT WILL TRY TO MOVE SOUTH ACROSS THE CWA THIS
EVENING...BUT LOOKS TO STALL NW-SE ACROSS CONVERSE COUNTY INTO THE
NORTHERN NEB PANHANDLE TONIGHT THRU EARLY SUNDAY. THIS SHOULD
MAINTAIN SHOWER/TSTORM DEVELOPMENT OVER THIS AREA THIS EVENING AND
AS THE UPPER WAVE MOVES ACROSS THE FORECAST AREA. A SECOND AND
STRONGER PV ANOMALY WILL APPROACH FROM THE WEST EARLY SUNDAY
MORNING...WITH A RE-INTENSIFICATION OF CONVECTION EXPECTED THROUGH
THE MORNING IN RESPONSE TO THE INCREASED UPPER FORCING. THE LEFT
EXIT REGION OF A 105 KT JET WILL MOVE OVERHEAD BY THE AFTERNOON AS
WELL...WITH THE SFC FRONT MAKING A RUN SOUTH ACROSS THE PLAINS
THROUGH THE LATE AFTERNOON. SO ANTICIPATE A GOOD COVERAGE OF
SHOWERS AND STORMS THROUGH THE DAY WITH THE COMBINATION OF SFC AND
UPPER FORCING...AND INCREASED POPS ANOTHER 5 TO 10 PERCENT FROM
THE PREVIOUS FORECAST. LOOKING AT GUSTY WINDS...SMALL HAIL AND
BRIEF MODERATE RAIN TO BE THE MAIN THREATS AS INSTABILITY VALUES
ARE PROGGED TO BE BETWEEN 500 AND 1000 J/KG THRU THE AFTERNOON
WITH ROUGHLY 30 KTS OF SHEAR OVERHEAD. MUCH DRIER AIR WILL MOVE IN
SUNDAY EVENING WITH STORMS PUSHING TO THE EAST. ANOTHER
COLD FRONT WILL APPROACH FROM THE NORTH MONDAY AFTERNOON AND
SHOULD INITIATE A FEW SHOWERS AND T-STORMS ACROSS THE PLAINS IN
THE AFTERNOON. OTHERWISE...SUNDAY AND MONDAY LOOK TO BE MUCH
COOLER THAN TODAY WITH THE PASSAGE OF THESE COLD FRONTS.

.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 418 PM MDT SAT AUG 30 2014

THE LONGWAVE UPPER TROUGH SHOULD CONTINUE SHIFTING EAST OF OUR
REGION TUESDAY WITH A DEEPLY DRY AIRMASS IN PLACE WITH MOST OF ANY
STRONGER SHORTWAVE ENERGY COMING DOWN THE NORTHWESTERLY FLOW ALOFT
REMAINING TO THE NORTH THROUGH AT LEAST WEDNESDAY. THIS PATTERN
WILL KEEP OUR AREA DRY THROUGH WEDNESDAY...POSSIBLY SIGNIFICANTLY
DRY WITH GFS SUGGESTING BOUNDARY LAYER DEWPOINTS GETTING INTO THE
UPPER TEENS FOR SOME AREAS OUT IN THE HIGHER TERRAIN AND WESTERN
ZONES TUESDAY INTO WEDNESDAY. SYNOPTIC SCALE PATTERN INDICATED IN
THE GFS/ECMWF SUGGESTIVE THAT WESTERLY/SOUTHWESTERLY DOWNSLOPE
WINDS WILL COME UP A BIT TUESDAY INTO WEDNESDAY AND WE ARE
FORECASTING THEM A LITTLE HIGHER THAN WHAT THE RAW MODEL GUIDANCE
SUGGESTS MIDWEEK WITH DEWPOINTS A FEW DEGREES DRIER AS WELL
(PLEASE REFER TO FIRE WEATHER SECTION OF THE DISCUSSION FOR MORE
INFORMATION ON POTENTIAL IMPACTS). OTHERWISE...GFS AND NOW THE ECMWF
BOTH IN FAIR AGREEMENT DEEPENING AN UPPER TROUGH ALONG THE WEST
COAST THURSDAY INTO FRIDAY...INDUCING A MORE SOUTHWESTERLY
MID/UPPER FLOW ACROSS OUR AREA GOING INTO LATE WEEK. THIS
PATTERN...IF IT DEVELOPS...SHOULD HELP US TAP INTO ANOTHER ROUND OF
PACIFIC MOISTURE COMING UP THROUGH THE 4 CORNERS REGION INTO
SOUTHERN WYOMING AND WESTERN NEBRASKA...SO WE CONTINUED PREVIOUS
FORECAST TREND OF BRINGING SLIGHT CHANCE TO LOCALLY CHANCE POPS
(HIGHER TERRAIN) FOR SHOWERS/THUNDERSTORMS BY LATE IN THE NEXT
WEEK.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY AFTERNOON)
ISSUED AT 458 PM MDT SAT AUG 30 2014

COLD FRONT CONTINUES TO MOVE INTO THE AREA FROM THE WEST AND
NORTHWEST. THIS FRONT SHOULD KEEP CONVECTION GOING THROUGH THE
EVENING HOURS...AND POSSIBLY ALL NIGHT AS IT MOVES THROUGH. THINK
WITH LOSS OF DAYTIME HEATING THOUGH...CONVECTION WILL LIKELY BE
LIMITED. WILL KEEP VFR CONDITIONS FOR ALL AIRPORTS THROUGH THIS
EVENING.


&&

.FIRE WEATHER...
ISSUED AT 418 PM MDT SAT AUG 30 2014

WIDELY SCATTERED SHOWERS AND THUNDERSTORMS WILL
CONTINUE THIS AFTERNOON AND EVENING FOR MUCH OF THE DISTRICT AS A
STRONG WEATHER DISTURBANCE MOVES THROUGH THE AREA. A WEAK COLD
FRONT WILL MOVE SOUTH ACROSS ZONES 301 AND 311...AND WILL STALL
ACROSS THIS AREA TONIGHT THROUGH EARLY SUNDAY. GUSTY WEST TO
SOUTHWEST WINDS OCCURRING THIS AFTERNOON SOUTH OF THE FRONT WILL
EASE TONIGHT...AND WILL INCREASE ONCE AGAIN THROUGH SUNDAY MORNING
WITH GUSTS BETWEEN 30 AND 40 MPH EXPECTED ALONG AND WEST OF THE
LARAMIE RANGE THROUGH THE AFTERNOON. WINDS ACROSS THE PLAINS WILL
BE GUSTING 25 TO 30 MPH IN THE LATE MORNING UNTIL THE FRONT
FINALLY PUSHES SOUTH ACROSS THIS AREA BETWEEN 1200 AND 1900.
SHOWERS AND T-STORMS WILL OCCUR ALONG THE FRONT AND AS ANOTHER
STRONG WEATHER DISTURBANCE MOVES OVER THE AREA THROUGH SUNDAY.
DRIER CONDITIONS WILL DEVELOP BY MIDDLE OF NEXT WEEK WHILE GUSTY
WEST WINDS CONTINUE IN AREAS ALONG AND WEST OF THE LARAMIE RANGE.
LOOKING FOR FIRE WEATHER CONCERNS TO INCREASE ACROSS THIS AREA AS
A RESULT.

&&

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

$$

UPDATE...HAMMER
SHORT TERM...RJM
LONG TERM...GARMON
AVIATION...CLAYCOMB
FIRE WEATHER...RJM






000
FXUS65 KCYS 310239
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
839 PM MDT SAT AUG 30 2014

.UPDATE...
ISSUED AT 826 PM MDT SAT AUG 30 2014

CONVECTION IS STARTING TO WIND DOWN ACROSS THE CWA THIS EVE. WIND
GUSTS IN EXCESS OF 45 MPH WERE COMMON WITH LARGE SFC TEMP-DEWPOINT
SPREADS AND RESULTANT INVERTED-V SOUNDING PROFILES. WE HAD ONE
STORM KICK OUT SOME INTENSE OUTFLOW AS IT MOVED OVER CYS AROUND
500 PM WITH GUSTS TO 60 MPH REPORTED AT THE INTERSTATE 80 PORT OF
ENTRY EAST OF CHEYENNE. MORE WIDESPREAD PCPN AND A GENERAL LOSS OF
DIURNAL HEATING HAS STABILIZED THINGS FOR THE REST OF THE NIGHT SO
DO NOT EXPECT ANYMORE BIG WIND GUSTS. SHOULD ALSO SEE LESS IN THE
WAY OF LIGHTNING STRIKES WITH MAINLY SHOWERS OVERNIGHT. WATER
VAPOR SATELLITE SHOWS THE LEAD SHORTWAVE MOVING ACROSS FAR EASTERN
WY AS OF 02Z. THIS IS RESPONSIBLE FOR ONGOING NUMEROUS SHOWERS AND
WEAK TSTMS OVER THE PANHANDLE. CLEARING/SUBSIDENCE IN THE WAKE OF
THIS FEATURE SHOULD SHUT PCPN OFF FOR A LITTLE WHILE. WENT AHEAD
AND KEPT ISOLATED POPS IN FOR MOST OF THE NIGHT AS THE MAIN COLD
FRONT IS STILL HANGING BACK OVER CENTRAL WY. FROPA OVERNIGHT AND
LARGER SCALE ASCENT ASSOCIATED WITH A LARGER PIECE OF SHORTWAVE
ENERGY CURRENTLY UPSTREAM WILL RESULT IN AN INCREASE IN SHOWERS
FROM WEST TO EAST BY DAYBREAK SUN. UPDATED POPS AND CLOUD TRENDS
BASED ON CURRENT RADAR/SATELLITE IMAGERY. OTHERWISE THE INHERITED
FCST IS IN GOOD SHAPE TONIGHT BASED ON OBS AND NEAR TERM HIGH-RES
MODELS.

&&

.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 418 PM MDT SAT AUG 30 2014

WATER VAPOR IMAGERY FROM THIS AFTERNOON SHOWS THE LEAD IMPULSE IN
A QUASI-ZONAL FLOW PATTERN ENTERING SOUTHWEST WYOMING THIS
AFTERNOON...WITH SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS
DEVELOPING OVER THE CWA OUT AHEAD OF THIS WAVE. THE FOCUS FOR
CONVECTIVE INITIATION WAS OVER THE MOUNTAINS EARLY THIS AFTERNOON...AND
ALONG VARIOUS BOUNDARIES THAT SET UP ALONG LARAMIE AND CONVERSE
COUNTIES THIS AFTERNOON. MLCAPES ARE UP TO 500 J/KG ACROSS THE
PLAINS ACCORDING TO SPC MESOANALYSIS...WITH DEEP LAYER SHEAR 20
KTS OR LESS. THEREFORE...EXPECT CONVECTION TO CONTINUE THROUGH
THIS EVENING INCLUDING LOCATIONS ACROSS THE NEB PANHANDLE AS THE
UPPER WAVE APPROACHES. BUT WITH LACK OF SIGNIFICANT INSTABILITY
AND SHEAR...STORMS SHOULD REMAIN RELATIVELY WEAK WITH GUSTY AND
ERRATIC WINDS THE MAIN IMPACT. WITH MODERATE SOUTHWEST WINDS ALREADY
IN PLACE OVER MUCH OF THE FORECAST AREA DUE TO 3MB/3HR PRESSURE
FALLS OVER THE HIGH PLAINS...TSTORM DOWNDRAFTS COULD AUGMENT THE
CURRENT WINDS SPEEDS...WITH GUSTS OF 50 TO 55 MPH GUSTS POSSIBLE
FROM ANY STORMS.

A COLD FRONT WILL TRY TO MOVE SOUTH ACROSS THE CWA THIS
EVENING...BUT LOOKS TO STALL NW-SE ACROSS CONVERSE COUNTY INTO THE
NORTHERN NEB PANHANDLE TONIGHT THRU EARLY SUNDAY. THIS SHOULD
MAINTAIN SHOWER/TSTORM DEVELOPMENT OVER THIS AREA THIS EVENING AND
AS THE UPPER WAVE MOVES ACROSS THE FORECAST AREA. A SECOND AND
STRONGER PV ANOMALY WILL APPROACH FROM THE WEST EARLY SUNDAY
MORNING...WITH A RE-INTENSIFICATION OF CONVECTION EXPECTED THROUGH
THE MORNING IN RESPONSE TO THE INCREASED UPPER FORCING. THE LEFT
EXIT REGION OF A 105 KT JET WILL MOVE OVERHEAD BY THE AFTERNOON AS
WELL...WITH THE SFC FRONT MAKING A RUN SOUTH ACROSS THE PLAINS
THROUGH THE LATE AFTERNOON. SO ANTICIPATE A GOOD COVERAGE OF
SHOWERS AND STORMS THROUGH THE DAY WITH THE COMBINATION OF SFC AND
UPPER FORCING...AND INCREASED POPS ANOTHER 5 TO 10 PERCENT FROM
THE PREVIOUS FORECAST. LOOKING AT GUSTY WINDS...SMALL HAIL AND
BRIEF MODERATE RAIN TO BE THE MAIN THREATS AS INSTABILITY VALUES
ARE PROGGED TO BE BETWEEN 500 AND 1000 J/KG THRU THE AFTERNOON
WITH ROUGHLY 30 KTS OF SHEAR OVERHEAD. MUCH DRIER AIR WILL MOVE IN
SUNDAY EVENING WITH STORMS PUSHING TO THE EAST. ANOTHER
COLD FRONT WILL APPROACH FROM THE NORTH MONDAY AFTERNOON AND
SHOULD INITIATE A FEW SHOWERS AND T-STORMS ACROSS THE PLAINS IN
THE AFTERNOON. OTHERWISE...SUNDAY AND MONDAY LOOK TO BE MUCH
COOLER THAN TODAY WITH THE PASSAGE OF THESE COLD FRONTS.

.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 418 PM MDT SAT AUG 30 2014

THE LONGWAVE UPPER TROUGH SHOULD CONTINUE SHIFTING EAST OF OUR
REGION TUESDAY WITH A DEEPLY DRY AIRMASS IN PLACE WITH MOST OF ANY
STRONGER SHORTWAVE ENERGY COMING DOWN THE NORTHWESTERLY FLOW ALOFT
REMAINING TO THE NORTH THROUGH AT LEAST WEDNESDAY. THIS PATTERN
WILL KEEP OUR AREA DRY THROUGH WEDNESDAY...POSSIBLY SIGNIFICANTLY
DRY WITH GFS SUGGESTING BOUNDARY LAYER DEWPOINTS GETTING INTO THE
UPPER TEENS FOR SOME AREAS OUT IN THE HIGHER TERRAIN AND WESTERN
ZONES TUESDAY INTO WEDNESDAY. SYNOPTIC SCALE PATTERN INDICATED IN
THE GFS/ECMWF SUGGESTIVE THAT WESTERLY/SOUTHWESTERLY DOWNSLOPE
WINDS WILL COME UP A BIT TUESDAY INTO WEDNESDAY AND WE ARE
FORECASTING THEM A LITTLE HIGHER THAN WHAT THE RAW MODEL GUIDANCE
SUGGESTS MIDWEEK WITH DEWPOINTS A FEW DEGREES DRIER AS WELL
(PLEASE REFER TO FIRE WEATHER SECTION OF THE DISCUSSION FOR MORE
INFORMATION ON POTENTIAL IMPACTS). OTHERWISE...GFS AND NOW THE ECMWF
BOTH IN FAIR AGREEMENT DEEPENING AN UPPER TROUGH ALONG THE WEST
COAST THURSDAY INTO FRIDAY...INDUCING A MORE SOUTHWESTERLY
MID/UPPER FLOW ACROSS OUR AREA GOING INTO LATE WEEK. THIS
PATTERN...IF IT DEVELOPS...SHOULD HELP US TAP INTO ANOTHER ROUND OF
PACIFIC MOISTURE COMING UP THROUGH THE 4 CORNERS REGION INTO
SOUTHERN WYOMING AND WESTERN NEBRASKA...SO WE CONTINUED PREVIOUS
FORECAST TREND OF BRINGING SLIGHT CHANCE TO LOCALLY CHANCE POPS
(HIGHER TERRAIN) FOR SHOWERS/THUNDERSTORMS BY LATE IN THE NEXT
WEEK.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY AFTERNOON)
ISSUED AT 458 PM MDT SAT AUG 30 2014

COLD FRONT CONTINUES TO MOVE INTO THE AREA FROM THE WEST AND
NORTHWEST. THIS FRONT SHOULD KEEP CONVECTION GOING THROUGH THE
EVENING HOURS...AND POSSIBLY ALL NIGHT AS IT MOVES THROUGH. THINK
WITH LOSS OF DAYTIME HEATING THOUGH...CONVECTION WILL LIKELY BE
LIMITED. WILL KEEP VFR CONDITIONS FOR ALL AIRPORTS THROUGH THIS
EVENING.


&&

.FIRE WEATHER...
ISSUED AT 418 PM MDT SAT AUG 30 2014

WIDELY SCATTERED SHOWERS AND THUNDERSTORMS WILL
CONTINUE THIS AFTERNOON AND EVENING FOR MUCH OF THE DISTRICT AS A
STRONG WEATHER DISTURBANCE MOVES THROUGH THE AREA. A WEAK COLD
FRONT WILL MOVE SOUTH ACROSS ZONES 301 AND 311...AND WILL STALL
ACROSS THIS AREA TONIGHT THROUGH EARLY SUNDAY. GUSTY WEST TO
SOUTHWEST WINDS OCCURRING THIS AFTERNOON SOUTH OF THE FRONT WILL
EASE TONIGHT...AND WILL INCREASE ONCE AGAIN THROUGH SUNDAY MORNING
WITH GUSTS BETWEEN 30 AND 40 MPH EXPECTED ALONG AND WEST OF THE
LARAMIE RANGE THROUGH THE AFTERNOON. WINDS ACROSS THE PLAINS WILL
BE GUSTING 25 TO 30 MPH IN THE LATE MORNING UNTIL THE FRONT
FINALLY PUSHES SOUTH ACROSS THIS AREA BETWEEN 1200 AND 1900.
SHOWERS AND T-STORMS WILL OCCUR ALONG THE FRONT AND AS ANOTHER
STRONG WEATHER DISTURBANCE MOVES OVER THE AREA THROUGH SUNDAY.
DRIER CONDITIONS WILL DEVELOP BY MIDDLE OF NEXT WEEK WHILE GUSTY
WEST WINDS CONTINUE IN AREAS ALONG AND WEST OF THE LARAMIE RANGE.
LOOKING FOR FIRE WEATHER CONCERNS TO INCREASE ACROSS THIS AREA AS
A RESULT.

&&

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

$$

UPDATE...HAMMER
SHORT TERM...RJM
LONG TERM...GARMON
AVIATION...CLAYCOMB
FIRE WEATHER...RJM







000
FXUS63 KUNR 302315
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
515 PM MDT SAT AUG 30 2014

.SHORT TERM...THIS EVENING THROUGH SUNDAY NIGHT
ISSUED AT 312 PM MDT SAT AUG 30 2014

CURRENT SURFACE ANALYSIS SHOWS LOW PRESSURE OVER FAR NORTHEAST
WY...WITH COLD FRONT FROM FAR EASTERN MT INTO CENTRAL WY. UPPER
LEVEL ANALYSIS SHOWS WEAK RIDGING OVER THE DAKOTAS WITH BROAD TROF
COVERING MUCH OF THE WESTERN CONUS. NUMEROUS SHORTWAVES ARE NOTED
WITHIN THE TROF...WITH THEM CURRENTLY OVER NORTHEAST MT...CENTRAL
WY AND SOUTH CENTRAL MT...AND EASTERN OR AND SOUTHWESTERN ID.
SKIES ARE VARIABLY CLOUDY OVER NORTHEAST WY...WITH MOSTLY SUNNY
SKIES TO THE EAST. ISOLATED SHOWERS AND STORMS HAVE STARTED TO
DEVELOP OVER NORTHEAST WY IN THE VICINITY OF THE COLD FRONT. TEMPS
RANGE FROM THE UPPER 70S TO UPPER 80S ACROSS THE AREA. WINDS ARE
SOUTH-SOUTHEAST...BREEZY AT TIMES OVER MOST OF THE AREA...EXCEPT
FOR NORTHWESTERLY WINDS OVER CAMPBELL CO BEHIND THE FRONT.

CHANCES FOR SHOWERS AND STORMS WILL INCREASE THROUGH THE LATE
AFTERNOON AND EVENING FROM WEST TO EAST...ESPECIALLY ACROSS NORTHERN
PORTIONS OF THE CWA...AS THE SHORTWAVE OVER WY MOVES EAST-NORTHEAST
THROUGH THE REGION. THE STRONGEST FORCING WITH THE WAVE MOVES ACROSS
NORTHERN PORTIONS OF THE CWA AND POINTS FURTHER TO THE NORTH THIS
EVENING. THIS IS WHERE THE BEST CHANCES FOR PCPN WILL BE...AS WELL
AS THE RISK FOR ISOLATED SEVERE STORMS. CHANCES FOR PCPN AND SEVERE
WEATHER WILL DECREASE FURTHER SOUTH ACROSS THE CWA...WITH ONLY
SLIGHT CHANCES FOR A SHOWER OR STORM OVER FAR SOUTHERN SD THROUGH
THE EVENING. THINKING FROM PREVIOUS FORECAST GENERALLY HOLDS...WITH
THE BEST THREAT FOR STRONG TO SEVERE STORMS GENERALLY NEAR OR NORTH
OF A LINE FROM GILLETTE TO NEAR SPEARFISH...TO FAITH AND DUPREE.
HOWEVER...THE SLIGHTLY LATER TIMING OF THIS WAVE ADDS SOME
UNCERTAINTY TO THE RISK...ESPECIALLY OVER EASTERN PORTIONS OF THE
RISK AREA LATER ON. INSTABILITY IS FAIRLY STRONG ACROSS THE
AREA...ESPECIALLY TO THE NORTH AND EAST OF THE BLACK HILLS LATE THIS
AFTERNOON INTO THE EVENING. SHEAR WILL ALSO BE STRONGEST TO THE
NORTH AND EAST OF THE SURFACE LOW AS IT SLOWLY TRACKS FROM NORTHEAST
WY THROUGH WESTERN SD THIS EVENING. THE MAIN THREATS FROM ANY SEVERE
STORMS WILL BE LARGE HAIL AND STRONG WIND GUSTS...BUT AN ISOLATED
TORNADO CANNOT BE TOTALLY RULED OUT OVER EXTREME NORTHEAST WY INTO
NORTHWEST SD. LOCALLY HEAVY RAINFALL IS ALSO POSSIBLE...ESPECIALLY
ACROSS FAR NORTHWESTERN SD. MOST OF THE ACTIVITY WITH THIS WAVE WILL
EXIT EAST OF THE CWA AROUND 06Z...WITH LINGERING ISOLATED LIGHTER
ACTIVITY POSSIBLE INTO THE OVERNIGHT OVER THE CWA. GUSTY NORTHWEST
WINDS WILL DEVELOP ACROSS THE WESTERN SD PLAINS DURING THE
EVENING...AFTER THE FRONT PASSES. THE STRONGEST WINDS WILL GENERALLY
BE IN THE RAPID CITY AREA...AS WELL AS THE NEARBY PLAINS TO THE
NORTH AND EAST. WINDS WILL GRADUALLY DECREASE AFTER MIDNIGHT.

THE NEXT SHORTWAVE OVER OR/ID WILL APPROACH OUR WESTERN ZONES BY
EARLY SUNDAY MORNING...WITH THIS ONE TRACKING A BIT FURTHER SOUTH
ACROSS THE CWA DURING THE DAY. THIS SYSTEM SHOULD BRING A MORE
WIDESPREAD COVERAGE OF PCPN ACROSS THE AREA...WITH COLDER AIR ALOFT
KEEPING THE ATMOSPHERE UNSTABLE. SHOWERS ARE LIKELY ACROSS THE BLACK
HILLS AREA...WITH A PRETTY GOOD CHANCE FOR SHOWERS ACROSS THE REST
OF THE CWA DURING THE DAY...ESPECIALLY IN THE LATE MORNING AND
AFTERNOON. A FEW THUNDERSTORMS ARE POSSIBLE...BUT CLOUD COVER AND
COOLER AIR WILL HELP TO KEEP CAPE VALUES RATHER LOW. HIGHS WILL ONLY
BE IN THE 70S ACROSS THE SD PLAINS...WITH 60S OVER THE BLACK HILLS
AND NORTHEAST WY. SHOWERS WILL EXIT EASTERN AREAS IN THE EVENING
WITH A COOL NIGHT ON TAP FOR MOST AREAS. YET ANOTHER DISTURBANCE IS
PROGGED TO APPROACH WESTERN PORTIONS OF THE AREA LATE SUNDAY NIGHT
OR MONDAY MORNING.

&&

.LONG TERM...MONDAY THROUGH SATURDAY
ISSUED AT 312 PM MDT SAT AUG 30 2014

SHORTWAVE EMBEDDED IN CYCLONIC FLOW WILL BRING CONTINUED CHANCES
FOR -SHRA/-TSRA MONDAY...BUT COVERAGE SHOULD BE LOWER THAN SUNDAY
ON THE PLAINS. UPPER TROUGH WILL SHARPEN OVER THE PACIFIC
NORTHWEST TUESDAY/WEDNESDAY BRINGING A FLAT UPPER RIDGE/THERMAL
RIDGE OVER THE CWA RESULTING IN DRIER/WARMER WEATHER. LONG TERM
GUIDANCE NOW SHOWING WEST/NORTHWEST FLOW ALOFT AND A SERIES OF
FRONTS DANCING ACROSS THE REGION FOR THURSDAY THROUGH SATURDAY.
RESULT WILL BE CHANCES FOR -SHRA/-TSRA ALONG WITH COOLER
TEMPERATURES FOR THE END OF NEXT WEEK.

&&

.AVIATION...FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING
ISSUED AT 514 PM MDT SAT AUG 30 2014

SCATTERED TSRA WILL MOVE ACROSS WY INTO WESTERN SD THROUGH THIS
EVENING. IFR VSBYS ARE EXPECTED WITH THE STRONGEST STORMS ALONG
WITH LARGE HAIL AND GUSTY WINDS. OUTSIDE OF STORMS...VFR
CONDITIONS ARE EXPECTED TONIGHT. ADDITIONAL SHRA/-TSRA WILL
DEVELOP EARLY SUNDAY AND PERSIST MUCH OF THE DAY WITH AREAS OF MVFR
CIGS/VSBYS.

&&

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

$$

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






000
FXUS63 KUNR 302315
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
515 PM MDT SAT AUG 30 2014

.SHORT TERM...THIS EVENING THROUGH SUNDAY NIGHT
ISSUED AT 312 PM MDT SAT AUG 30 2014

CURRENT SURFACE ANALYSIS SHOWS LOW PRESSURE OVER FAR NORTHEAST
WY...WITH COLD FRONT FROM FAR EASTERN MT INTO CENTRAL WY. UPPER
LEVEL ANALYSIS SHOWS WEAK RIDGING OVER THE DAKOTAS WITH BROAD TROF
COVERING MUCH OF THE WESTERN CONUS. NUMEROUS SHORTWAVES ARE NOTED
WITHIN THE TROF...WITH THEM CURRENTLY OVER NORTHEAST MT...CENTRAL
WY AND SOUTH CENTRAL MT...AND EASTERN OR AND SOUTHWESTERN ID.
SKIES ARE VARIABLY CLOUDY OVER NORTHEAST WY...WITH MOSTLY SUNNY
SKIES TO THE EAST. ISOLATED SHOWERS AND STORMS HAVE STARTED TO
DEVELOP OVER NORTHEAST WY IN THE VICINITY OF THE COLD FRONT. TEMPS
RANGE FROM THE UPPER 70S TO UPPER 80S ACROSS THE AREA. WINDS ARE
SOUTH-SOUTHEAST...BREEZY AT TIMES OVER MOST OF THE AREA...EXCEPT
FOR NORTHWESTERLY WINDS OVER CAMPBELL CO BEHIND THE FRONT.

CHANCES FOR SHOWERS AND STORMS WILL INCREASE THROUGH THE LATE
AFTERNOON AND EVENING FROM WEST TO EAST...ESPECIALLY ACROSS NORTHERN
PORTIONS OF THE CWA...AS THE SHORTWAVE OVER WY MOVES EAST-NORTHEAST
THROUGH THE REGION. THE STRONGEST FORCING WITH THE WAVE MOVES ACROSS
NORTHERN PORTIONS OF THE CWA AND POINTS FURTHER TO THE NORTH THIS
EVENING. THIS IS WHERE THE BEST CHANCES FOR PCPN WILL BE...AS WELL
AS THE RISK FOR ISOLATED SEVERE STORMS. CHANCES FOR PCPN AND SEVERE
WEATHER WILL DECREASE FURTHER SOUTH ACROSS THE CWA...WITH ONLY
SLIGHT CHANCES FOR A SHOWER OR STORM OVER FAR SOUTHERN SD THROUGH
THE EVENING. THINKING FROM PREVIOUS FORECAST GENERALLY HOLDS...WITH
THE BEST THREAT FOR STRONG TO SEVERE STORMS GENERALLY NEAR OR NORTH
OF A LINE FROM GILLETTE TO NEAR SPEARFISH...TO FAITH AND DUPREE.
HOWEVER...THE SLIGHTLY LATER TIMING OF THIS WAVE ADDS SOME
UNCERTAINTY TO THE RISK...ESPECIALLY OVER EASTERN PORTIONS OF THE
RISK AREA LATER ON. INSTABILITY IS FAIRLY STRONG ACROSS THE
AREA...ESPECIALLY TO THE NORTH AND EAST OF THE BLACK HILLS LATE THIS
AFTERNOON INTO THE EVENING. SHEAR WILL ALSO BE STRONGEST TO THE
NORTH AND EAST OF THE SURFACE LOW AS IT SLOWLY TRACKS FROM NORTHEAST
WY THROUGH WESTERN SD THIS EVENING. THE MAIN THREATS FROM ANY SEVERE
STORMS WILL BE LARGE HAIL AND STRONG WIND GUSTS...BUT AN ISOLATED
TORNADO CANNOT BE TOTALLY RULED OUT OVER EXTREME NORTHEAST WY INTO
NORTHWEST SD. LOCALLY HEAVY RAINFALL IS ALSO POSSIBLE...ESPECIALLY
ACROSS FAR NORTHWESTERN SD. MOST OF THE ACTIVITY WITH THIS WAVE WILL
EXIT EAST OF THE CWA AROUND 06Z...WITH LINGERING ISOLATED LIGHTER
ACTIVITY POSSIBLE INTO THE OVERNIGHT OVER THE CWA. GUSTY NORTHWEST
WINDS WILL DEVELOP ACROSS THE WESTERN SD PLAINS DURING THE
EVENING...AFTER THE FRONT PASSES. THE STRONGEST WINDS WILL GENERALLY
BE IN THE RAPID CITY AREA...AS WELL AS THE NEARBY PLAINS TO THE
NORTH AND EAST. WINDS WILL GRADUALLY DECREASE AFTER MIDNIGHT.

THE NEXT SHORTWAVE OVER OR/ID WILL APPROACH OUR WESTERN ZONES BY
EARLY SUNDAY MORNING...WITH THIS ONE TRACKING A BIT FURTHER SOUTH
ACROSS THE CWA DURING THE DAY. THIS SYSTEM SHOULD BRING A MORE
WIDESPREAD COVERAGE OF PCPN ACROSS THE AREA...WITH COLDER AIR ALOFT
KEEPING THE ATMOSPHERE UNSTABLE. SHOWERS ARE LIKELY ACROSS THE BLACK
HILLS AREA...WITH A PRETTY GOOD CHANCE FOR SHOWERS ACROSS THE REST
OF THE CWA DURING THE DAY...ESPECIALLY IN THE LATE MORNING AND
AFTERNOON. A FEW THUNDERSTORMS ARE POSSIBLE...BUT CLOUD COVER AND
COOLER AIR WILL HELP TO KEEP CAPE VALUES RATHER LOW. HIGHS WILL ONLY
BE IN THE 70S ACROSS THE SD PLAINS...WITH 60S OVER THE BLACK HILLS
AND NORTHEAST WY. SHOWERS WILL EXIT EASTERN AREAS IN THE EVENING
WITH A COOL NIGHT ON TAP FOR MOST AREAS. YET ANOTHER DISTURBANCE IS
PROGGED TO APPROACH WESTERN PORTIONS OF THE AREA LATE SUNDAY NIGHT
OR MONDAY MORNING.

&&

.LONG TERM...MONDAY THROUGH SATURDAY
ISSUED AT 312 PM MDT SAT AUG 30 2014

SHORTWAVE EMBEDDED IN CYCLONIC FLOW WILL BRING CONTINUED CHANCES
FOR -SHRA/-TSRA MONDAY...BUT COVERAGE SHOULD BE LOWER THAN SUNDAY
ON THE PLAINS. UPPER TROUGH WILL SHARPEN OVER THE PACIFIC
NORTHWEST TUESDAY/WEDNESDAY BRINGING A FLAT UPPER RIDGE/THERMAL
RIDGE OVER THE CWA RESULTING IN DRIER/WARMER WEATHER. LONG TERM
GUIDANCE NOW SHOWING WEST/NORTHWEST FLOW ALOFT AND A SERIES OF
FRONTS DANCING ACROSS THE REGION FOR THURSDAY THROUGH SATURDAY.
RESULT WILL BE CHANCES FOR -SHRA/-TSRA ALONG WITH COOLER
TEMPERATURES FOR THE END OF NEXT WEEK.

&&

.AVIATION...FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING
ISSUED AT 514 PM MDT SAT AUG 30 2014

SCATTERED TSRA WILL MOVE ACROSS WY INTO WESTERN SD THROUGH THIS
EVENING. IFR VSBYS ARE EXPECTED WITH THE STRONGEST STORMS ALONG
WITH LARGE HAIL AND GUSTY WINDS. OUTSIDE OF STORMS...VFR
CONDITIONS ARE EXPECTED TONIGHT. ADDITIONAL SHRA/-TSRA WILL
DEVELOP EARLY SUNDAY AND PERSIST MUCH OF THE DAY WITH AREAS OF MVFR
CIGS/VSBYS.

&&

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

$$

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







000
FXUS65 KCYS 302301
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
501 PM MDT SAT AUG 30 2014

.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 418 PM MDT SAT AUG 30 2014

WATER VAPOR IMAGERY FROM THIS AFTERNOON SHOWS THE LEAD IMPULSE IN
A QUASI-ZONAL FLOW PATTERN ENTERING SOUTHWEST WYOMING THIS
AFTERNOON...WITH SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS
DEVELOPING OVER THE CWA OUT AHEAD OF THIS WAVE. THE FOCUS FOR
CONVECTIVE INITIATION WAS OVER THE MOUNTAINS EARLY THIS AFTERNOON...AND
ALONG VARIOUS BOUNDARIES THAT SET UP ALONG LARAMIE AND CONVERSE
COUNTIES THIS AFTERNOON. MLCAPES ARE UP TO 500 J/KG ACROSS THE
PLAINS ACCORDING TO SPC MESOANALYSIS...WITH DEEP LAYER SHEAR 20
KTS OR LESS. THEREFORE...EXPECT CONVECTION TO CONTINUE THROUGH
THIS EVENING INCLUDING LOCATIONS ACROSS THE NEB PANHANDLE AS THE
UPPER WAVE APPROACHES. BUT WITH LACK OF SIGNIFICANT INSTABILITY
AND SHEAR...STORMS SHOULD REMAIN RELATIVELY WEAK WITH GUSTY AND
ERRATIC WINDS THE MAIN IMPACT. WITH MODERATE SOUTHWEST WINDS ALREADY
IN PLACE OVER MUCH OF THE FORECAST AREA DUE TO 3MB/3HR PRESSURE
FALLS OVER THE HIGH PLAINS...TSTORM DOWNDRAFTS COULD AUGMENT THE
CURRENT WINDS SPEEDS...WITH GUSTS OF 50 TO 55 MPH GUSTS POSSIBLE
FROM ANY STORMS.

A COLD FRONT WILL TRY TO MOVE SOUTH ACROSS THE CWA THIS
EVENING...BUT LOOKS TO STALL NW-SE ACROSS CONVERSE COUNTY INTO THE
NORTHERN NEB PANHANDLE TONIGHT THRU EARLY SUNDAY. THIS SHOULD
MAINTAIN SHOWER/TSTORM DEVELOPMENT OVER THIS AREA THIS EVENING AND
AS THE UPPER WAVE MOVES ACROSS THE FORECAST AREA. A SECOND AND
STRONGER PV ANOMALY WILL APPROACH FROM THE WEST EARLY SUNDAY
MORNING...WITH A RE-INTENSIFICATION OF CONVECTION EXPECTED THROUGH
THE MORNING IN RESPONSE TO THE INCREASED UPPER FORCING. THE LEFT
EXIT REGION OF A 105 KT JET WILL MOVE OVERHEAD BY THE AFTERNOON AS
WELL...WITH THE SFC FRONT MAKING A RUN SOUTH ACROSS THE PLAINS
THROUGH THE LATE AFTERNOON. SO ANTICIPATE A GOOD COVERAGE OF
SHOWERS AND STORMS THROUGH THE DAY WITH THE COMBINATION OF SFC AND
UPPER FORCING...AND INCREASED POPS ANOTHER 5 TO 10 PERCENT FROM
THE PREVIOUS FORECAST. LOOKING AT GUSTY WINDS...SMALL HAIL AND
BRIEF MODERATE RAIN TO BE THE MAIN THREATS AS INSTABILITY VALUES
ARE PROGGED TO BE BETWEEN 500 AND 1000 J/KG THRU THE AFTERNOON
WITH ROUGHLY 30 KTS OF SHEAR OVERHEAD. MUCH DRIER AIR WILL MOVE IN
SUNDAY EVENING WITH STORMS PUSHING TO THE EAST. ANOTHER
COLD FRONT WILL APPROACH FROM THE NORTH MONDAY AFTERNOON AND
SHOULD INITIATE A FEW SHOWERS AND T-STORMS ACROSS THE PLAINS IN
THE AFTERNOON. OTHERWISE...SUNDAY AND MONDAY LOOK TO BE MUCH
COOLER THAN TODAY WITH THE PASSAGE OF THESE COLD FRONTS.

.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 418 PM MDT SAT AUG 30 2014

THE LONGWAVE UPPER TROUGH SHOULD CONTINUE SHIFTING EAST OF OUR
REGION TUESDAY WITH A DEEPLY DRY AIRMASS IN PLACE WITH MOST OF ANY
STRONGER SHORTWAVE ENERGY COMING DOWN THE NORTHWESTERLY FLOW ALOFT
REMAINING TO THE NORTH THROUGH AT LEAST WEDNESDAY. THIS PATTERN
WILL KEEP OUR AREA DRY THROUGH WEDNESDAY...POSSIBLY SIGNIFICANTLY
DRY WITH GFS SUGGESTING BOUNDARY LAYER DEWPOINTS GETTING INTO THE
UPPER TEENS FOR SOME AREAS OUT IN THE HIGHER TERRAIN AND WESTERN
ZONES TUESDAY INTO WEDNESDAY. SYNOPTIC SCALE PATTERN INDICATED IN
THE GFS/ECMWF SUGGESTIVE THAT WESTERLY/SOUTHWESTERLY DOWNSLOPE
WINDS WILL COME UP A BIT TUESDAY INTO WEDNESDAY AND WE ARE
FORECASTING THEM A LITTLE HIGHER THAN WHAT THE RAW MODEL GUIDANCE
SUGGESTS MIDWEEK WITH DEWPOINTS A FEW DEGREES DRIER AS WELL
(PLEASE REFER TO FIRE WEATHER SECTION OF THE DISCUSSION FOR MORE
INFORMATION ON POTENTIAL IMPACTS). OTHERWISE...GFS AND NOW THE ECMWF
BOTH IN FAIR AGREEMENT DEEPENING AN UPPER TROUGH ALONG THE WEST
COAST THURSDAY INTO FRIDAY...INDUCING A MORE SOUTHWESTERLY
MID/UPPER FLOW ACROSS OUR AREA GOING INTO LATE WEEK. THIS
PATTERN...IF IT DEVELOPS...SHOULD HELP US TAP INTO ANOTHER ROUND OF
PACIFIC MOISTURE COMING UP THROUGH THE 4 CORNERS REGION INTO
SOUTHERN WYOMING AND WESTERN NEBRASKA...SO WE CONTINUED PREVIOUS
FORECAST TREND OF BRINGING SLIGHT CHANCE TO LOCALLY CHANCE POPS
(HIGHER TERRAIN) FOR SHOWERS/THUNDERSTORMS BY LATE IN THE NEXT
WEEK.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY AFTERNOON)
ISSUED AT 458 PM MDT SAT AUG 30 2014

COLD FRONT CONTINUES TO MOVE INTO THE AREA FROM THE WEST AND
NORTHWEST. THIS FRONT SHOULD KEEP CONVECTION GOING THROUGH THE
EVENING HOURS...AND POSSIBLY ALL NIGHT AS IT MOVES THROUGH. THINK
WITH LOSS OF DAYTIME HEATING THOUGH...CONVECTION WILL LIKELY BE
LIMITED. WILL KEEP VFR CONDITIONS FOR ALL AIRPORTS THROUGH THIS
EVENING.

&&

.FIRE WEATHER...
ISSUED AT 418 PM MDT SAT AUG 30 2014

WIDELY SCATTERED SHOWERS AND THUNDERSTORMS WILL
CONTINUE THIS AFTERNOON AND EVENING FOR MUCH OF THE DISTRICT AS A
STRONG WEATHER DISTURBANCE MOVES THROUGH THE AREA. A WEAK COLD
FRONT WILL MOVE SOUTH ACROSS ZONES 301 AND 311...AND WILL STALL
ACROSS THIS AREA TONIGHT THROUGH EARLY SUNDAY. GUSTY WEST TO
SOUTHWEST WINDS OCCURRING THIS AFTERNOON SOUTH OF THE FRONT WILL
EASE TONIGHT...AND WILL INCREASE ONCE AGAIN THROUGH SUNDAY MORNING
WITH GUSTS BETWEEN 30 AND 40 MPH EXPECTED ALONG AND WEST OF THE
LARAMIE RANGE THROUGH THE AFTERNOON. WINDS ACROSS THE PLAINS WILL
BE GUSTING 25 TO 30 MPH IN THE LATE MORNING UNTIL THE FRONT
FINALLY PUSHES SOUTH ACROSS THIS AREA BETWEEN 1200 AND 1900.
SHOWERS AND T-STORMS WILL OCCUR ALONG THE FRONT AND AS ANOTHER
STRONG WEATHER DISTURBANCE MOVES OVER THE AREA THROUGH SUNDAY.
DRIER CONDITIONS WILL DEVELOP BY MIDDLE OF NEXT WEEK WHILE GUSTY
WEST WINDS CONTINUE IN AREAS ALONG AND WEST OF THE LARAMIE RANGE.
LOOKING FOR FIRE WEATHER CONCERNS TO INCREASE ACROSS THIS AREA AS
A RESULT.

&&

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

$$

SHORT TERM...RJM
LONG TERM...GARMON
AVIATION...CLAYCOMB
FIRE WEATHER...RJM







000
FXUS65 KCYS 302301
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
501 PM MDT SAT AUG 30 2014

.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 418 PM MDT SAT AUG 30 2014

WATER VAPOR IMAGERY FROM THIS AFTERNOON SHOWS THE LEAD IMPULSE IN
A QUASI-ZONAL FLOW PATTERN ENTERING SOUTHWEST WYOMING THIS
AFTERNOON...WITH SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS
DEVELOPING OVER THE CWA OUT AHEAD OF THIS WAVE. THE FOCUS FOR
CONVECTIVE INITIATION WAS OVER THE MOUNTAINS EARLY THIS AFTERNOON...AND
ALONG VARIOUS BOUNDARIES THAT SET UP ALONG LARAMIE AND CONVERSE
COUNTIES THIS AFTERNOON. MLCAPES ARE UP TO 500 J/KG ACROSS THE
PLAINS ACCORDING TO SPC MESOANALYSIS...WITH DEEP LAYER SHEAR 20
KTS OR LESS. THEREFORE...EXPECT CONVECTION TO CONTINUE THROUGH
THIS EVENING INCLUDING LOCATIONS ACROSS THE NEB PANHANDLE AS THE
UPPER WAVE APPROACHES. BUT WITH LACK OF SIGNIFICANT INSTABILITY
AND SHEAR...STORMS SHOULD REMAIN RELATIVELY WEAK WITH GUSTY AND
ERRATIC WINDS THE MAIN IMPACT. WITH MODERATE SOUTHWEST WINDS ALREADY
IN PLACE OVER MUCH OF THE FORECAST AREA DUE TO 3MB/3HR PRESSURE
FALLS OVER THE HIGH PLAINS...TSTORM DOWNDRAFTS COULD AUGMENT THE
CURRENT WINDS SPEEDS...WITH GUSTS OF 50 TO 55 MPH GUSTS POSSIBLE
FROM ANY STORMS.

A COLD FRONT WILL TRY TO MOVE SOUTH ACROSS THE CWA THIS
EVENING...BUT LOOKS TO STALL NW-SE ACROSS CONVERSE COUNTY INTO THE
NORTHERN NEB PANHANDLE TONIGHT THRU EARLY SUNDAY. THIS SHOULD
MAINTAIN SHOWER/TSTORM DEVELOPMENT OVER THIS AREA THIS EVENING AND
AS THE UPPER WAVE MOVES ACROSS THE FORECAST AREA. A SECOND AND
STRONGER PV ANOMALY WILL APPROACH FROM THE WEST EARLY SUNDAY
MORNING...WITH A RE-INTENSIFICATION OF CONVECTION EXPECTED THROUGH
THE MORNING IN RESPONSE TO THE INCREASED UPPER FORCING. THE LEFT
EXIT REGION OF A 105 KT JET WILL MOVE OVERHEAD BY THE AFTERNOON AS
WELL...WITH THE SFC FRONT MAKING A RUN SOUTH ACROSS THE PLAINS
THROUGH THE LATE AFTERNOON. SO ANTICIPATE A GOOD COVERAGE OF
SHOWERS AND STORMS THROUGH THE DAY WITH THE COMBINATION OF SFC AND
UPPER FORCING...AND INCREASED POPS ANOTHER 5 TO 10 PERCENT FROM
THE PREVIOUS FORECAST. LOOKING AT GUSTY WINDS...SMALL HAIL AND
BRIEF MODERATE RAIN TO BE THE MAIN THREATS AS INSTABILITY VALUES
ARE PROGGED TO BE BETWEEN 500 AND 1000 J/KG THRU THE AFTERNOON
WITH ROUGHLY 30 KTS OF SHEAR OVERHEAD. MUCH DRIER AIR WILL MOVE IN
SUNDAY EVENING WITH STORMS PUSHING TO THE EAST. ANOTHER
COLD FRONT WILL APPROACH FROM THE NORTH MONDAY AFTERNOON AND
SHOULD INITIATE A FEW SHOWERS AND T-STORMS ACROSS THE PLAINS IN
THE AFTERNOON. OTHERWISE...SUNDAY AND MONDAY LOOK TO BE MUCH
COOLER THAN TODAY WITH THE PASSAGE OF THESE COLD FRONTS.

.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 418 PM MDT SAT AUG 30 2014

THE LONGWAVE UPPER TROUGH SHOULD CONTINUE SHIFTING EAST OF OUR
REGION TUESDAY WITH A DEEPLY DRY AIRMASS IN PLACE WITH MOST OF ANY
STRONGER SHORTWAVE ENERGY COMING DOWN THE NORTHWESTERLY FLOW ALOFT
REMAINING TO THE NORTH THROUGH AT LEAST WEDNESDAY. THIS PATTERN
WILL KEEP OUR AREA DRY THROUGH WEDNESDAY...POSSIBLY SIGNIFICANTLY
DRY WITH GFS SUGGESTING BOUNDARY LAYER DEWPOINTS GETTING INTO THE
UPPER TEENS FOR SOME AREAS OUT IN THE HIGHER TERRAIN AND WESTERN
ZONES TUESDAY INTO WEDNESDAY. SYNOPTIC SCALE PATTERN INDICATED IN
THE GFS/ECMWF SUGGESTIVE THAT WESTERLY/SOUTHWESTERLY DOWNSLOPE
WINDS WILL COME UP A BIT TUESDAY INTO WEDNESDAY AND WE ARE
FORECASTING THEM A LITTLE HIGHER THAN WHAT THE RAW MODEL GUIDANCE
SUGGESTS MIDWEEK WITH DEWPOINTS A FEW DEGREES DRIER AS WELL
(PLEASE REFER TO FIRE WEATHER SECTION OF THE DISCUSSION FOR MORE
INFORMATION ON POTENTIAL IMPACTS). OTHERWISE...GFS AND NOW THE ECMWF
BOTH IN FAIR AGREEMENT DEEPENING AN UPPER TROUGH ALONG THE WEST
COAST THURSDAY INTO FRIDAY...INDUCING A MORE SOUTHWESTERLY
MID/UPPER FLOW ACROSS OUR AREA GOING INTO LATE WEEK. THIS
PATTERN...IF IT DEVELOPS...SHOULD HELP US TAP INTO ANOTHER ROUND OF
PACIFIC MOISTURE COMING UP THROUGH THE 4 CORNERS REGION INTO
SOUTHERN WYOMING AND WESTERN NEBRASKA...SO WE CONTINUED PREVIOUS
FORECAST TREND OF BRINGING SLIGHT CHANCE TO LOCALLY CHANCE POPS
(HIGHER TERRAIN) FOR SHOWERS/THUNDERSTORMS BY LATE IN THE NEXT
WEEK.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY AFTERNOON)
ISSUED AT 458 PM MDT SAT AUG 30 2014

COLD FRONT CONTINUES TO MOVE INTO THE AREA FROM THE WEST AND
NORTHWEST. THIS FRONT SHOULD KEEP CONVECTION GOING THROUGH THE
EVENING HOURS...AND POSSIBLY ALL NIGHT AS IT MOVES THROUGH. THINK
WITH LOSS OF DAYTIME HEATING THOUGH...CONVECTION WILL LIKELY BE
LIMITED. WILL KEEP VFR CONDITIONS FOR ALL AIRPORTS THROUGH THIS
EVENING.

&&

.FIRE WEATHER...
ISSUED AT 418 PM MDT SAT AUG 30 2014

WIDELY SCATTERED SHOWERS AND THUNDERSTORMS WILL
CONTINUE THIS AFTERNOON AND EVENING FOR MUCH OF THE DISTRICT AS A
STRONG WEATHER DISTURBANCE MOVES THROUGH THE AREA. A WEAK COLD
FRONT WILL MOVE SOUTH ACROSS ZONES 301 AND 311...AND WILL STALL
ACROSS THIS AREA TONIGHT THROUGH EARLY SUNDAY. GUSTY WEST TO
SOUTHWEST WINDS OCCURRING THIS AFTERNOON SOUTH OF THE FRONT WILL
EASE TONIGHT...AND WILL INCREASE ONCE AGAIN THROUGH SUNDAY MORNING
WITH GUSTS BETWEEN 30 AND 40 MPH EXPECTED ALONG AND WEST OF THE
LARAMIE RANGE THROUGH THE AFTERNOON. WINDS ACROSS THE PLAINS WILL
BE GUSTING 25 TO 30 MPH IN THE LATE MORNING UNTIL THE FRONT
FINALLY PUSHES SOUTH ACROSS THIS AREA BETWEEN 1200 AND 1900.
SHOWERS AND T-STORMS WILL OCCUR ALONG THE FRONT AND AS ANOTHER
STRONG WEATHER DISTURBANCE MOVES OVER THE AREA THROUGH SUNDAY.
DRIER CONDITIONS WILL DEVELOP BY MIDDLE OF NEXT WEEK WHILE GUSTY
WEST WINDS CONTINUE IN AREAS ALONG AND WEST OF THE LARAMIE RANGE.
LOOKING FOR FIRE WEATHER CONCERNS TO INCREASE ACROSS THIS AREA AS
A RESULT.

&&

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

$$

SHORT TERM...RJM
LONG TERM...GARMON
AVIATION...CLAYCOMB
FIRE WEATHER...RJM






000
FXUS65 KCYS 302218
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
418 PM MDT SAT AUG 30 2014

.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 418 PM MDT SAT AUG 30 2014

WATER VAPOR IMAGERY FROM THIS AFTERNOON SHOWS THE LEAD IMPULSE IN
A QUASI-ZONAL FLOW PATTERN ENTERING SOUTHWEST WYOMING THIS
AFTERNOON...WITH SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS
DEVELOPING OVER THE CWA OUT AHEAD OF THIS WAVE. THE FOCUS FOR
CONVECTIVE INITIATION WAS OVER THE MOUNTAINS EARLY THIS AFTERNOON...AND
ALONG VARIOUS BOUNDARIES THAT SET UP ALONG LARAMIE AND CONVERSE
COUNTIES THIS AFTERNOON. MLCAPES ARE UP TO 500 J/KG ACROSS THE
PLAINS ACCORDING TO SPC MESOANALYSIS...WITH DEEP LAYER SHEAR 20
KTS OR LESS. THEREFORE...EXPECT CONVECTION TO CONTINUE THROUGH
THIS EVENING INCLUDING LOCATIONS ACROSS THE NEB PANHANDLE AS THE
UPPER WAVE APPROACHES. BUT WITH LACK OF SIGNIFICANT INSTABILITY
AND SHEAR...STORMS SHOULD REMAIN RELATIVELY WEAK WITH GUSTY AND
ERRATIC WINDS THE MAIN IMPACT. WITH MODERATE SOUTHWEST WINDS ALREADY
IN PLACE OVER MUCH OF THE FORECAST AREA DUE TO 3MB/3HR PRESSURE
FALLS OVER THE HIGH PLAINS...TSTORM DOWNDRAFTS COULD AUGMENT THE
CURRENT WINDS SPEEDS...WITH GUSTS OF 50 TO 55 MPH GUSTS POSSIBLE
FROM ANY STORMS.

A COLD FRONT WILL TRY TO MOVE SOUTH ACROSS THE CWA THIS
EVENING...BUT LOOKS TO STALL NW-SE ACROSS CONVERSE COUNTY INTO THE
NORTHERN NEB PANHANDLE TONIGHT THRU EARLY SUNDAY. THIS SHOULD
MAINTAIN SHOWER/TSTORM DEVELOPMENT OVER THIS AREA THIS EVENING AND
AS THE UPPER WAVE MOVES ACROSS THE FORECAST AREA. A SECOND AND
STRONGER PV ANOMALY WILL APPROACH FROM THE WEST EARLY SUNDAY
MORNING...WITH A RE-INTENSIFICATION OF CONVECTION EXPECTED THROUGH
THE MORNING IN RESPONSE TO THE INCREASED UPPER FORCING. THE LEFT
EXIT REGION OF A 105 KT JET WILL MOVE OVERHEAD BY THE AFTERNOON AS
WELL...WITH THE SFC FRONT MAKING A RUN SOUTH ACROSS THE PLAINS
THROUGH THE LATE AFTERNOON. SO ANTICIPATE A GOOD COVERAGE OF
SHOWERS AND STORMS THROUGH THE DAY WITH THE COMBINATION OF SFC AND
UPPER FORCING...AND INCREASED POPS ANOTHER 5 TO 10 PERCENT FROM
THE PREVIOUS FORECAST. LOOKING AT GUSTY WINDS...SMALL HAIL AND
BRIEF MODERATE RAIN TO BE THE MAIN THREATS AS INSTABILITY VALUES
ARE PROGGED TO BE BETWEEN 500 AND 1000 J/KG THRU THE AFTERNOON
WITH ROUGHLY 30 KTS OF SHEAR OVERHEAD. MUCH DRIER AIR WILL MOVE IN
SUNDAY EVENING WITH STORMS PUSHING TO THE EAST. ANOTHER
COLD FRONT WILL APPROACH FROM THE NORTH MONDAY AFTERNOON AND
SHOULD INITIATE A FEW SHOWERS AND T-STORMS ACROSS THE PLAINS IN
THE AFTERNOON. OTHERWISE...SUNDAY AND MONDAY LOOK TO BE MUCH
COOLER THAN TODAY WITH THE PASSAGE OF THESE COLD FRONTS.

.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 418 PM MDT SAT AUG 30 2014

THE LONGWAVE UPPER TROUGH SHOULD CONTINUE SHIFTING EAST OF OUR
REGION TUESDAY WITH A DEEPLY DRY AIRMASS IN PLACE WITH MOST OF ANY
STRONGER SHORTWAVE ENERGY COMING DOWN THE NORTHWESTERLY FLOW ALOFT
REMAINING TO THE NORTH THROUGH AT LEAST WEDNESDAY. THIS PATTERN
WILL KEEP OUR AREA DRY THROUGH WEDNESDAY...POSSIBLY SIGNIFICANTLY
DRY WITH GFS SUGGESTING BOUNDARY LAYER DEWPOINTS GETTING INTO THE
UPPER TEENS FOR SOME AREAS OUT IN THE HIGHER TERRAIN AND WESTERN
ZONES TUESDAY INTO WEDNESDAY. SYNOPTIC SCALE PATTERN INDICATED IN
THE GFS/ECMWF SUGGESTIVE THAT WESTERLY/SOUTHWESTERLY DOWNSLOPE
WINDS WILL COME UP A BIT TUESDAY INTO WEDNESDAY AND WE ARE
FORECASTING THEM A LITTLE HIGHER THAN WHAT THE RAW MODEL GUIDANCE
SUGGESTS MIDWEEK WITH DEWPOINTS A FEW DEGREES DRIER AS WELL
(PLEASE REFER TO FIRE WEATHER SECTION OF THE DISCUSSION FOR MORE
INFORMATION ON POTENTIAL IMPACTS). OTHERWISE...GFS AND NOW THE ECMWF
BOTH IN FAIR AGREEMENT DEEPENING AN UPPER TROUGH ALONG THE WEST
COAST THURSDAY INTO FRIDAY...INDUCING A MORE SOUTHWESTERLY
MID/UPPER FLOW ACROSS OUR AREA GOING INTO LATE WEEK. THIS
PATTERN...IF IT DEVELOPS...SHOULD HELP US TAP INTO ANOTHER ROUND OF
PACIFIC MOISTURE COMING UP THROUGH THE 4 CORNERS REGION INTO
SOUTHERN WYOMING AND WESTERN NEBRASKA...SO WE CONTINUED PREVIOUS
FORECAST TREND OF BRINGING SLIGHT CHANCE TO LOCALLY CHANCE POPS
(HIGHER TERRAIN) FOR SHOWERS/THUNDERSTORMS BY LATE IN THE NEXT
WEEK.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY MORNING)
ISSUED AT 12 PM MDT SAT AUG 30 2014

SHORT TERM FORECAST TRENDS STILL SUGGEST THAT WE WILL SEE ISOLATED
SHOWERS AND THUNDERSTORMS FORMING IN THE HIGHER TERRAIN WEST OF
CHEYENNE IN THE MID AFTERNOON HOURS. LATEST HIGH RESOLUTION RAPID
REFRESH MODEL RUNS DEVELOP CONVECTION AROUND RAWLINS AND LARAMIE
AROUND 21Z...WORKING IT EASTWARD ACROSS THE CHEYENNE AREA MID TO LATE
AFTERNOON...THEN WEAKENING IT AS IT MOVES INTO THE MORE HIGHLY
CAPPED ATMOSPHERE OVER THE NEBRASKA PANHANDLE 00Z-03Z. HRRR
TIMING CLOSE TO OUR THINKING AS WELL ON TIMING FOR
SHOWERS/THUNDERSTORMS IN VICINITY OF EACH FORECAST LOCATION. DIDNT
MENTION VICINITY THUNDERSTORMS AT ALLIANCE AND SYDNEY DUE TO
GREATER CAP IN THE EAST. CEILINGS AND VISIBILITIES PREVAILING VFR
ALL PERIODS. COVERAGES OF SHOWERS AND STORMS NOT HIGH ENOUGH THIS
AFTERNOON AND EVENING FOR PREVAILING MENTION BELOW VFR CATEGORY.

&&

.FIRE WEATHER...
ISSUED AT 418 PM MDT SAT AUG 30 2014

WIDELY SCATTERED SHOWERS AND THUNDERSTORMS WILL
CONTINUE THIS AFTERNOON AND EVENING FOR MUCH OF THE DISTRICT AS A
STRONG WEATHER DISTURBANCE MOVES THROUGH THE AREA. A WEAK COLD
FRONT WILL MOVE SOUTH ACROSS ZONES 301 AND 311...AND WILL STALL
ACROSS THIS AREA TONIGHT THROUGH EARLY SUNDAY. GUSTY WEST TO
SOUTHWEST WINDS OCCURRING THIS AFTERNOON SOUTH OF THE FRONT WILL
EASE TONIGHT...AND WILL INCREASE ONCE AGAIN THROUGH SUNDAY MORNING
WITH GUSTS BETWEEN 30 AND 40 MPH EXPECTED ALONG AND WEST OF THE
LARAMIE RANGE THROUGH THE AFTERNOON. WINDS ACROSS THE PLAINS WILL
BE GUSTING 25 TO 30 MPH IN THE LATE MORNING UNTIL THE FRONT
FINALLY PUSHES SOUTH ACROSS THIS AREA BETWEEN 1200 AND 1900.
SHOWERS AND T-STORMS WILL OCCUR ALONG THE FRONT AND AS ANOTHER
STRONG WEATHER DISTURBANCE MOVES OVER THE AREA THROUGH SUNDAY.
DRIER CONDITIONS WILL DEVELOP BY MIDDLE OF NEXT WEEK WHILE GUSTY
WEST WINDS CONTINUE IN AREAS ALONG AND WEST OF THE LARAMIE RANGE.
LOOKING FOR FIRE WEATHER CONCERNS TO INCREASE ACROSS THIS AREA AS
A RESULT.

&&

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

$$

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








000
FXUS63 KUNR 302112
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
312 PM MDT SAT AUG 30 2014

.SHORT TERM...THIS EVENING THROUGH SUNDAY NIGHT
ISSUED AT 312 PM MDT SAT AUG 30 2014

CURRENT SURFACE ANALYSIS SHOWS LOW PRESSURE OVER FAR NORTHEAST
WY...WITH COLD FRONT FROM FAR EASTERN MT INTO CENTRAL WY. UPPER
LEVEL ANALYSIS SHOWS WEAK RIDGING OVER THE DAKOTAS WITH BROAD TROF
COVERING MUCH OF THE WESTERN CONUS. NUMEROUS SHORTWAVES ARE NOTED
WITHIN THE TROF...WITH THEM CURRENTLY OVER NORTHEAST MT...CENTRAL
WY AND SOUTH CENTRAL MT...AND EASTERN OR AND SOUTHWESTERN ID.
SKIES ARE VARIABLY CLOUDY OVER NORTHEAST WY...WITH MOSTLY SUNNY
SKIES TO THE EAST. ISOLATED SHOWERS AND STORMS HAVE STARTED TO
DEVELOP OVER NORTHEAST WY IN THE VICINITY OF THE COLD FRONT. TEMPS
RANGE FROM THE UPPER 70S TO UPPER 80S ACROSS THE AREA. WINDS ARE
SOUTH-SOUTHEAST...BREEZY AT TIMES OVER MOST OF THE AREA...EXCEPT
FOR NORTHWESTERLY WINDS OVER CAMPBELL CO BEHIND THE FRONT.

CHANCES FOR SHOWERS AND STORMS WILL INCREASE THROUGH THE LATE
AFTERNOON AND EVENING FROM WEST TO EAST...ESPECIALLY ACROSS NORTHERN
PORTIONS OF THE CWA...AS THE SHORTWAVE OVER WY MOVES EAST-NORTHEAST
THROUGH THE REGION. THE STRONGEST FORCING WITH THE WAVE MOVES ACROSS
NORTHERN PORTIONS OF THE CWA AND POINTS FURTHER TO THE NORTH THIS
EVENING. THIS IS WHERE THE BEST CHANCES FOR PCPN WILL BE...AS WELL
AS THE RISK FOR ISOLATED SEVERE STORMS. CHANCES FOR PCPN AND SEVERE
WEATHER WILL DECREASE FURTHER SOUTH ACROSS THE CWA...WITH ONLY
SLIGHT CHANCES FOR A SHOWER OR STORM OVER FAR SOUTHERN SD THROUGH
THE EVENING. THINKING FROM PREVIOUS FORECAST GENERALLY HOLDS...WITH
THE BEST THREAT FOR STRONG TO SEVERE STORMS GENERALLY NEAR OR NORTH
OF A LINE FROM GILLETTE TO NEAR SPEARFISH...TO FAITH AND DUPREE.
HOWEVER...THE SLIGHTLY LATER TIMING OF THIS WAVE ADDS SOME
UNCERTAINTY TO THE RISK...ESPECIALLY OVER EASTERN PORTIONS OF THE
RISK AREA LATER ON. INSTABILITY IS FAIRLY STRONG ACROSS THE
AREA...ESPECIALLY TO THE NORTH AND EAST OF THE BLACK HILLS LATE THIS
AFTERNOON INTO THE EVENING. SHEAR WILL ALSO BE STRONGEST TO THE
NORTH AND EAST OF THE SURFACE LOW AS IT SLOWLY TRACKS FROM NORTHEAST
WY THROUGH WESTERN SD THIS EVENING. THE MAIN THREATS FROM ANY SEVERE
STORMS WILL BE LARGE HAIL AND STRONG WIND GUSTS...BUT AN ISOLATED
TORNADO CANNOT BE TOTALLY RULED OUT OVER EXTREME NORTHEAST WY INTO
NORTHWEST SD. LOCALLY HEAVY RAINFALL IS ALSO POSSIBLE...ESPECIALLY
ACROSS FAR NORTHWESTERN SD. MOST OF THE ACTIVITY WITH THIS WAVE WILL
EXIT EAST OF THE CWA AROUND 06Z...WITH LINGERING ISOLATED LIGHTER
ACTIVITY POSSIBLE INTO THE OVERNIGHT OVER THE CWA. GUSTY NORTHWEST
WINDS WILL DEVELOP ACROSS THE WESTERN SD PLAINS DURING THE
EVENING...AFTER THE FRONT PASSES. THE STRONGEST WINDS WILL GENERALLY
BE IN THE RAPID CITY AREA...AS WELL AS THE NEARBY PLAINS TO THE
NORTH AND EAST. WINDS WILL GRADUALLY DECREASE AFTER MIDNIGHT.

THE NEXT SHORTWAVE OVER OR/ID WILL APPROACH OUR WESTERN ZONES BY
EARLY SUNDAY MORNING...WITH THIS ONE TRACKING A BIT FURTHER SOUTH
ACROSS THE CWA DURING THE DAY. THIS SYSTEM SHOULD BRING A MORE
WIDESPREAD COVERAGE OF PCPN ACROSS THE AREA...WITH COLDER AIR ALOFT
KEEPING THE ATMOSPHERE UNSTABLE. SHOWERS ARE LIKELY ACROSS THE BLACK
HILLS AREA...WITH A PRETTY GOOD CHANCE FOR SHOWERS ACROSS THE REST
OF THE CWA DURING THE DAY...ESPECIALLY IN THE LATE MORNING AND
AFTERNOON. A FEW THUNDERSTORMS ARE POSSIBLE...BUT CLOUD COVER AND
COOLER AIR WILL HELP TO KEEP CAPE VALUES RATHER LOW. HIGHS WILL ONLY
BE IN THE 70S ACROSS THE SD PLAINS...WITH 60S OVER THE BLACK HILLS
AND NORTHEAST WY. SHOWERS WILL EXIT EASTERN AREAS IN THE EVENING
WITH A COOL NIGHT ON TAP FOR MOST AREAS. YET ANOTHER DISTURBANCE IS
PROGGED TO APPROACH WESTERN PORTIONS OF THE AREA LATE SUNDAY NIGHT
OR MONDAY MORNING.

&&

.LONG TERM...MONDAY THROUGH SATURDAY
ISSUED AT 312 PM MDT SAT AUG 30 2014

SHORTWAVE EMBEDDED IN CYCLONIC FLOW WILL BRING CONTINUED CHANCES
FOR -SHRA/-TSRA MONDAY...BUT COVERAGE SHOULD BE LOWER THAN SUNDAY
ON THE PLAINS. UPPER TROUGH WILL SHARPEN OVER THE PACIFIC
NORTHWEST TUESDAY/WEDNESDAY BRINGING A FLAT UPPER RIDGE/THERMAL
RIDGE OVER THE CWA RESULTING IN DRIER/WARMER WEATHER. LONG TERM
GUIDANCE NOW SHOWING WEST/NORTHWEST FLOW ALOFT AND A SERIES OF
FRONTS DANCING ACROSS THE REGION FOR THURSDAY THROUGH SATURDAY.
RESULT WILL BE CHANCES FOR -SHRA/-TSRA ALONG WITH COOLER
TEMPERATURES FOR THE END OF NEXT WEEK.

&&

.AVIATION...FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING
ISSUED AT 312 PM MDT SAT AUG 30 2014

SCATTERED TSRA WILL MOVE ACROSS WY INTO WESTERN SD THROUGH THIS
EVENING. IFR VSBYS ARE EXPECTED WITH THE STRONGEST STORMS ALONG
WITH HAIL/GUSTY WINDS. OUTSIDE OF STORMS...VFR CONDITIONS ARE
EXPECTED TONIGHT. ADDITIONAL SHRA/-TSRA WILL DEVELOP EARLY SUNDAY
AND PERSIST MUCH OF THE DAY WITH LOCAL MVFR CIGS/VSBYS.

&&

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

$$

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






000
FXUS65 KRIW 302022
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
222 PM MDT SAT AUG 30 2014

.SHORT TERM...TONIGHT THROUGH SUNDAY

PROGRESSIVE EVOLVING UPR PATTERN WITH BROADENING TROF ACROSS THE WRN
CONUS...SW FLOW OVERHEAD WY...AND SW RIDGING OVR THE PLAINS. FIRST
EMBEDDED SW WITHIN THE TROF IS HEADING INTO THE WRN/NWRN PORTIONS OF
THE STATE THIS MORNING...AND WILL CONTINUE TO EXPAND ACROSS WY
THROUGHOUT THE DAY AND NIGHT PERIODS. AT THE SFC...DEVELOPING LOW
PRESSURE OVR THE BIG HORN BASIN...WITH WARM FRONT EXTENDING OF TO
THE E/SE...AND COLD FRONT(S) OFF TO THE N/NW FROM THIS LOW.

TODAY/TONIGHT...THE PROGRESSIVE NATURE OF THE UPR LVLS WILL CONTINUE
TO SPREAD STRONGER UPR LVL FLOW OVERHEAD RESULTING IN INCREASED NET
UPWARD LIFT THRU TODAY AND OVERNIGHT. THIS WILL CONTINUE TO GREATLY
IMPROVE CONVECTIVE CHANCES AND GROWTH POTENTIAL TODAY AND INTO THE
EVENING PERIOD. A FEW STRONG/MARGINALLY SVR STORMS EXPECTED WITH ML
CAPE RANGING FROM 500 TO 1000 J/KG AND DEEP SHEAR OF 40 TO 50 KTS
THIS AFTERNOON OVER THE NORTHERN ZONES. STRONGER STORMS WILL BE
CHARACTERIZED AS FAST MOVING AT 30 TO 40 KTS...WITH HAIL AND STRONG
GUSTY WINDS APPROACHING SEVERE LEVELS FOR A FEW HOURS THIS
AFTERNOON. ELSEWHERE...STORM WILL HAVE STRONG GUSTY WINDS WITH BRIEF
HEAVY RAIN AND SMALL HAIL. SHEAR TODAY IS PRIMARILY AVAILABLE IN THE
FORM OF SPEED SHEAR W/ HEIGHT...WITH INCREASING UNIDIRECTIONAL SW
FLOW ACROSS MUCH OF THE CWA. THIS WILL ALSO LEND ITSELF TO AMBIENT
WEST TO SOUTHWEST WINDS BLOWING 20 PLUS MPH TO BEGIN WITH.
OVERALL...SIGNIFICANT HYDRO POTENTIAL DOES NOT LOOK TO BE AN ISSUE
AT THIS TIME WITH THESE FAST MOVING STORMS...EXCEPT IN THE CASE OF A
TRAINING SITUATION. CONVECTIVE SNOW SHOWERS WILL ALSO BE POSSIBLE
OVERNIGHT AND THROUGH THE DAY SUNDAY...FIRST STARTING OUR ABOVE
10500 FT THIS EVENING...AND DECREASING AROUND 9000 FT BY EVENING
SUNDAY.

SUNDAY...THE UPR TROF CONTINUES CROSSING/EXPANDING ACROSS THE STATE
FROM W TO E...WITH MUCH COOLER CONDITIONS FOR SURE BUT CONTINUED
GUSTY W TO WSW WINDS ACROSS THE SRN FA...AND GUSTY N TO NW WINDS
BEHIND THE FRONT...WITH ANOTHER SFC COLD FRONT POISED TO ENTER THE
STATE FROM THE NORTH THROUGH THE DAY. SHOWERS AND ISOLATED THUNDER
WILL BE RATHER PREVALENT ACROSS THE ENTIRE CWA FROM MORNING THROUGH
EARLY AFTERNOON BEFORE DECREASING FROM W TO E LATER IN THE DAY AND
EVENING. STRONGER STORMS WITH SMALL HAIL AND GUSTY WINDS WILL BE
MOST PROBABLY ACROSS NATRONA AND EASTERN FREMONT AND SWEETWATER
COUNTIES NEAR A FRONTAL BOUNDARY.

.LONG TERM...SUNDAY NIGHT THROUGH SATURDAY

SUNDAY NIGHT AN UPPER LEVEL LOW PRESSURE TROUGH WILL BE PASSING
THROUGH THE AREA SUPPORTING SOME SHOWERS AND ISOLATED
THUNDERSTORMS...MOST NUMEROUS OVER THE NORTHERN MOUNTAINS IN THE
EVENING.  SOME CONVECTION WILL LINGER THROUGH THE NIGHT.

MONDAY AND MONDAY NIGHT AS THE TROUGH CONTINUE TO MOVE EAST...
HIGH PRESSURE RIDGING WILL OCCUR OVER THE PACIFIC NORTHWEST.  SOME
SHOWERS MAY LINGER ACROSS THE WEST BUT THE MAIN TREND WILL BE FOR
DRYING WITH BREEZY TO WINDY CONDITIONS ACROSS THE SOUTH INTO
CENTRAL AREAS.

TUESDAY AND TUESDAY NIGHT DRY HIGH PRESSURE IS EXPECTED TO DOMINATE
THE WEATHER ACROSS THE AREA WITH INCREASING WEST TO SOUTHWEST WINDS
CENTRAL AND SOUTH WITH GENERAL WARMING.

WEDNESDAY AND WEDNESDAY NIGHT  SOME MID LEVEL CLOUDS ARE EXPECTED TO
MOVE UP FROM THE GREAT BASIN IN THE AFTERNOON...OTHERWISE THE DRY
HIGH PRESSURE IS EXPECTED TO CONTINUE TO DOMINATE THE WEATHER WITH
CONTINUED SOUTHWEST WINDS ACROSS THE CENTRAL AND SOUTH.

THURSDAY AND THURSDAY NIGHT  HIGH PRESSURE WILL SHIFT EAST WITH
INCREASING SOUTHWEST FLOW ALOFT BRINGING SOME PACIFIC MOISTURE ALOFT
OVER THE AREA.  SHOWERS ARE EXPECTED TO DEVELOP WITH ISOLATED
THUNDERSTORMS IN THE AFTERNOON...MOST NUMEROUS OVER THE WESTERN AND
CENTRAL MOUNTAINS.  INCREASED CLOUD COVER WILL BRING SOME COOLING.

FRIDAY AND FRIDAY NIGHT  SHOWERS AND ISOLATED THUNDERSTORMS ARE
EXPECTED TO INCREASE OVER THE AREA AS PACIFIC MOISTURE INCREASES IN
SOUTHWEST FLOW ALOFT.  A WEAK COLD FRONT WILL MOVE SLOWLY SOUTH FROM
MONTANA INTO NORTHERN WYOMING.

SATURDAY SOUTHWEST FLOW ALOFT WILL REMAIN IN PLACE OVER THE AREA
WITH A STREAM OF PACIFIC MOISTURE CONTINUING TO ADVECT INTO THE AREA
SUPPORTING SCATTERED SHOWERS AND SOME ISOLATED AFTERNOON
THUNDERSTORMS.  A FRONT IS EXPECTED TO HANG OUT ACROSS NORTHERN
WYOMING OSCILLATING NORTH AND SOUTH WITH SOME COOLING.  THE FRONT
WILL BE FIGHTING THE FLOW ALOFT AND THE AMOUNT OF COOLING IS IN
QUESTION.  OVERALL MODELS ARE IN FAIR AGREEMENT THROUGH THE MID TERM
AND EXTENDED FORECAST WITH THE GREATEST MODEL SPREAD TO THE NORTH
OVER CANADA...ESPECIALLY IN THE HUDSON BAY AREA.

&&

.AVIATION.../00Z ISSUANCE/

AN EVOLVING LARGE UPPER LEVEL TROUGH WITH SEVERAL EMBEDDED
DISTURBANCES WILL PUSH ACROSS THE FORECAST AREA THROUGH THE FORECAST
PERIOD. THIS SYSTEM WILL DESTABILIZE THE ATMOSPHERE AND PUSH A
COUPLE OF COLD FRONTS SOUTH ACROSS NORTH AND CENTRAL WYOMING THIS
EVENING AND THE AGAIN SUNDAY MORNING THROUGH THE AFTERNOON. THESE
BOUNDARIES WILL HELP TO FOCUS STRONGER THUNDERSTORMS THIS
EVENING...PRIMARILY VCNTY AND NORTH OF A KDUB-KWRL-50SM S KBYG LINE.
THESE STORMS WILL BE MOVING AT A GOOD CLIP...30 TO 40 KTS...WITH
SOME OF THESE STORMS CAPABLE OF MARGINALLY SEVERE HAIL AND WIND
GUSTS WITH BRIEF MVFR/IFR CONDITIONS. SOUTH OF THIS LINE...WSW WINDS AT
20-30KTS WITH GUSTS TO 40 MPH WILL CONTINUE INTO THE EARLY EVENING
BEFORE DECREASING. ALSO EXPECT ISOLATED TO WIDELY SCT THUNDERSTORMS.
THE MAIN HAZARD WITH THESE STORMS WILL BE ERRATIC OUTFLOW WIND GUSTS
NEAR 45KTS. SHOWERS AND ISOLATED THUNDER WILL CONTINUE ACROSS MUCH
OF THE REGION OVERNIGHT. THE BACK SIDE OF THIS TROUGH WILL THEN PUSH
INTO WESTERN WYOMING EARLY SUNDAY MORNING SPREADING EASTWARD WITH
SCT-NMRS SHRA/ISOLD TSRA AND HIGHER MTN OBSCURATIONS ACROSS THE
STATE...BUT PRIMARILY VCNTY AND N OF A KJAC-KLND-KCPR LINE.
KJAC...KCOD AND KPNA ARE MOST LIKELY TO SEE MVFR CIGS AFTER
06Z...BUT ESPECIALLY POST FRONTAL IN THE COOLER AIRMASS AFTER 10Z.

&&

.FIRE WEATHER...

AN EVOLVING LARGE UPPER LEVEL TROUGH WITH SEVERAL EMBEDDED
DISTURBANCES WILL PUSH ACROSS THE FORECAST AREA THROUGH SUNDAY AND
PART OF MONDAY. THIS SYSTEM WILL DESTABILIZE THE ATMOSPHERE AND PUSH
A FEW COLD FRONTS SOUTH ACROSS NORTH AND CENTRAL WYOMING THIS
AFTERNOON...AGAIN SUNDAY MORNING...AND FINALLY MONDAY AFTERNOON.
TODAY`S FRONT WILL BE THE FOCUS FOR STRONGER THUNDERSTORMS...
PRIMARILY NEAR AND NORTH OF A DUBOIS TO WORLAND TO GILLETTE LINE.
THESE STORMS WILL BE MOVING QUITE FAST AT AROUND 35 TO 40 KTS...WITH
SOME OF THESE STORMS CAPABLE OF MARGINALLY SEVERE HAIL AND WIND
GUSTS. SOUTH OF THE FRONT(S)...WEST TO WEST SOUTHWEST WINDS AT 20-25
MPH WITH GUSTS TO 40 MPH WILL BE POSSIBLE ALONG WITH MINIMUM RH
VALUES OF AROUND 20 PERCENT. THIS TOGETHER WITH ISOLATED TO WIDELY
SCT THUNDERSTORMS AND ERRATIC OUTFLOW WIND GUSTS NEAR 45KTS WILL
BRING ENHANCED FIRE DANGER TO THIS REGION FOR A FEW HOURS.

&&

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

$$

SHORT TERM...BRAUN
LONG TERM...C.BAKER
AVIATION...BRAUN
FIRE WEATHER...BRAUN






000
FXUS65 KRIW 302022
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
222 PM MDT SAT AUG 30 2014

.SHORT TERM...TONIGHT THROUGH SUNDAY

PROGRESSIVE EVOLVING UPR PATTERN WITH BROADENING TROF ACROSS THE WRN
CONUS...SW FLOW OVERHEAD WY...AND SW RIDGING OVR THE PLAINS. FIRST
EMBEDDED SW WITHIN THE TROF IS HEADING INTO THE WRN/NWRN PORTIONS OF
THE STATE THIS MORNING...AND WILL CONTINUE TO EXPAND ACROSS WY
THROUGHOUT THE DAY AND NIGHT PERIODS. AT THE SFC...DEVELOPING LOW
PRESSURE OVR THE BIG HORN BASIN...WITH WARM FRONT EXTENDING OF TO
THE E/SE...AND COLD FRONT(S) OFF TO THE N/NW FROM THIS LOW.

TODAY/TONIGHT...THE PROGRESSIVE NATURE OF THE UPR LVLS WILL CONTINUE
TO SPREAD STRONGER UPR LVL FLOW OVERHEAD RESULTING IN INCREASED NET
UPWARD LIFT THRU TODAY AND OVERNIGHT. THIS WILL CONTINUE TO GREATLY
IMPROVE CONVECTIVE CHANCES AND GROWTH POTENTIAL TODAY AND INTO THE
EVENING PERIOD. A FEW STRONG/MARGINALLY SVR STORMS EXPECTED WITH ML
CAPE RANGING FROM 500 TO 1000 J/KG AND DEEP SHEAR OF 40 TO 50 KTS
THIS AFTERNOON OVER THE NORTHERN ZONES. STRONGER STORMS WILL BE
CHARACTERIZED AS FAST MOVING AT 30 TO 40 KTS...WITH HAIL AND STRONG
GUSTY WINDS APPROACHING SEVERE LEVELS FOR A FEW HOURS THIS
AFTERNOON. ELSEWHERE...STORM WILL HAVE STRONG GUSTY WINDS WITH BRIEF
HEAVY RAIN AND SMALL HAIL. SHEAR TODAY IS PRIMARILY AVAILABLE IN THE
FORM OF SPEED SHEAR W/ HEIGHT...WITH INCREASING UNIDIRECTIONAL SW
FLOW ACROSS MUCH OF THE CWA. THIS WILL ALSO LEND ITSELF TO AMBIENT
WEST TO SOUTHWEST WINDS BLOWING 20 PLUS MPH TO BEGIN WITH.
OVERALL...SIGNIFICANT HYDRO POTENTIAL DOES NOT LOOK TO BE AN ISSUE
AT THIS TIME WITH THESE FAST MOVING STORMS...EXCEPT IN THE CASE OF A
TRAINING SITUATION. CONVECTIVE SNOW SHOWERS WILL ALSO BE POSSIBLE
OVERNIGHT AND THROUGH THE DAY SUNDAY...FIRST STARTING OUR ABOVE
10500 FT THIS EVENING...AND DECREASING AROUND 9000 FT BY EVENING
SUNDAY.

SUNDAY...THE UPR TROF CONTINUES CROSSING/EXPANDING ACROSS THE STATE
FROM W TO E...WITH MUCH COOLER CONDITIONS FOR SURE BUT CONTINUED
GUSTY W TO WSW WINDS ACROSS THE SRN FA...AND GUSTY N TO NW WINDS
BEHIND THE FRONT...WITH ANOTHER SFC COLD FRONT POISED TO ENTER THE
STATE FROM THE NORTH THROUGH THE DAY. SHOWERS AND ISOLATED THUNDER
WILL BE RATHER PREVALENT ACROSS THE ENTIRE CWA FROM MORNING THROUGH
EARLY AFTERNOON BEFORE DECREASING FROM W TO E LATER IN THE DAY AND
EVENING. STRONGER STORMS WITH SMALL HAIL AND GUSTY WINDS WILL BE
MOST PROBABLY ACROSS NATRONA AND EASTERN FREMONT AND SWEETWATER
COUNTIES NEAR A FRONTAL BOUNDARY.

.LONG TERM...SUNDAY NIGHT THROUGH SATURDAY

SUNDAY NIGHT AN UPPER LEVEL LOW PRESSURE TROUGH WILL BE PASSING
THROUGH THE AREA SUPPORTING SOME SHOWERS AND ISOLATED
THUNDERSTORMS...MOST NUMEROUS OVER THE NORTHERN MOUNTAINS IN THE
EVENING.  SOME CONVECTION WILL LINGER THROUGH THE NIGHT.

MONDAY AND MONDAY NIGHT AS THE TROUGH CONTINUE TO MOVE EAST...
HIGH PRESSURE RIDGING WILL OCCUR OVER THE PACIFIC NORTHWEST.  SOME
SHOWERS MAY LINGER ACROSS THE WEST BUT THE MAIN TREND WILL BE FOR
DRYING WITH BREEZY TO WINDY CONDITIONS ACROSS THE SOUTH INTO
CENTRAL AREAS.

TUESDAY AND TUESDAY NIGHT DRY HIGH PRESSURE IS EXPECTED TO DOMINATE
THE WEATHER ACROSS THE AREA WITH INCREASING WEST TO SOUTHWEST WINDS
CENTRAL AND SOUTH WITH GENERAL WARMING.

WEDNESDAY AND WEDNESDAY NIGHT  SOME MID LEVEL CLOUDS ARE EXPECTED TO
MOVE UP FROM THE GREAT BASIN IN THE AFTERNOON...OTHERWISE THE DRY
HIGH PRESSURE IS EXPECTED TO CONTINUE TO DOMINATE THE WEATHER WITH
CONTINUED SOUTHWEST WINDS ACROSS THE CENTRAL AND SOUTH.

THURSDAY AND THURSDAY NIGHT  HIGH PRESSURE WILL SHIFT EAST WITH
INCREASING SOUTHWEST FLOW ALOFT BRINGING SOME PACIFIC MOISTURE ALOFT
OVER THE AREA.  SHOWERS ARE EXPECTED TO DEVELOP WITH ISOLATED
THUNDERSTORMS IN THE AFTERNOON...MOST NUMEROUS OVER THE WESTERN AND
CENTRAL MOUNTAINS.  INCREASED CLOUD COVER WILL BRING SOME COOLING.

FRIDAY AND FRIDAY NIGHT  SHOWERS AND ISOLATED THUNDERSTORMS ARE
EXPECTED TO INCREASE OVER THE AREA AS PACIFIC MOISTURE INCREASES IN
SOUTHWEST FLOW ALOFT.  A WEAK COLD FRONT WILL MOVE SLOWLY SOUTH FROM
MONTANA INTO NORTHERN WYOMING.

SATURDAY SOUTHWEST FLOW ALOFT WILL REMAIN IN PLACE OVER THE AREA
WITH A STREAM OF PACIFIC MOISTURE CONTINUING TO ADVECT INTO THE AREA
SUPPORTING SCATTERED SHOWERS AND SOME ISOLATED AFTERNOON
THUNDERSTORMS.  A FRONT IS EXPECTED TO HANG OUT ACROSS NORTHERN
WYOMING OSCILLATING NORTH AND SOUTH WITH SOME COOLING.  THE FRONT
WILL BE FIGHTING THE FLOW ALOFT AND THE AMOUNT OF COOLING IS IN
QUESTION.  OVERALL MODELS ARE IN FAIR AGREEMENT THROUGH THE MID TERM
AND EXTENDED FORECAST WITH THE GREATEST MODEL SPREAD TO THE NORTH
OVER CANADA...ESPECIALLY IN THE HUDSON BAY AREA.

&&

.AVIATION.../00Z ISSUANCE/

AN EVOLVING LARGE UPPER LEVEL TROUGH WITH SEVERAL EMBEDDED
DISTURBANCES WILL PUSH ACROSS THE FORECAST AREA THROUGH THE FORECAST
PERIOD. THIS SYSTEM WILL DESTABILIZE THE ATMOSPHERE AND PUSH A
COUPLE OF COLD FRONTS SOUTH ACROSS NORTH AND CENTRAL WYOMING THIS
EVENING AND THE AGAIN SUNDAY MORNING THROUGH THE AFTERNOON. THESE
BOUNDARIES WILL HELP TO FOCUS STRONGER THUNDERSTORMS THIS
EVENING...PRIMARILY VCNTY AND NORTH OF A KDUB-KWRL-50SM S KBYG LINE.
THESE STORMS WILL BE MOVING AT A GOOD CLIP...30 TO 40 KTS...WITH
SOME OF THESE STORMS CAPABLE OF MARGINALLY SEVERE HAIL AND WIND
GUSTS WITH BRIEF MVFR/IFR CONDITIONS. SOUTH OF THIS LINE...WSW WINDS AT
20-30KTS WITH GUSTS TO 40 MPH WILL CONTINUE INTO THE EARLY EVENING
BEFORE DECREASING. ALSO EXPECT ISOLATED TO WIDELY SCT THUNDERSTORMS.
THE MAIN HAZARD WITH THESE STORMS WILL BE ERRATIC OUTFLOW WIND GUSTS
NEAR 45KTS. SHOWERS AND ISOLATED THUNDER WILL CONTINUE ACROSS MUCH
OF THE REGION OVERNIGHT. THE BACK SIDE OF THIS TROUGH WILL THEN PUSH
INTO WESTERN WYOMING EARLY SUNDAY MORNING SPREADING EASTWARD WITH
SCT-NMRS SHRA/ISOLD TSRA AND HIGHER MTN OBSCURATIONS ACROSS THE
STATE...BUT PRIMARILY VCNTY AND N OF A KJAC-KLND-KCPR LINE.
KJAC...KCOD AND KPNA ARE MOST LIKELY TO SEE MVFR CIGS AFTER
06Z...BUT ESPECIALLY POST FRONTAL IN THE COOLER AIRMASS AFTER 10Z.

&&

.FIRE WEATHER...

AN EVOLVING LARGE UPPER LEVEL TROUGH WITH SEVERAL EMBEDDED
DISTURBANCES WILL PUSH ACROSS THE FORECAST AREA THROUGH SUNDAY AND
PART OF MONDAY. THIS SYSTEM WILL DESTABILIZE THE ATMOSPHERE AND PUSH
A FEW COLD FRONTS SOUTH ACROSS NORTH AND CENTRAL WYOMING THIS
AFTERNOON...AGAIN SUNDAY MORNING...AND FINALLY MONDAY AFTERNOON.
TODAY`S FRONT WILL BE THE FOCUS FOR STRONGER THUNDERSTORMS...
PRIMARILY NEAR AND NORTH OF A DUBOIS TO WORLAND TO GILLETTE LINE.
THESE STORMS WILL BE MOVING QUITE FAST AT AROUND 35 TO 40 KTS...WITH
SOME OF THESE STORMS CAPABLE OF MARGINALLY SEVERE HAIL AND WIND
GUSTS. SOUTH OF THE FRONT(S)...WEST TO WEST SOUTHWEST WINDS AT 20-25
MPH WITH GUSTS TO 40 MPH WILL BE POSSIBLE ALONG WITH MINIMUM RH
VALUES OF AROUND 20 PERCENT. THIS TOGETHER WITH ISOLATED TO WIDELY
SCT THUNDERSTORMS AND ERRATIC OUTFLOW WIND GUSTS NEAR 45KTS WILL
BRING ENHANCED FIRE DANGER TO THIS REGION FOR A FEW HOURS.

&&

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

$$

SHORT TERM...BRAUN
LONG TERM...C.BAKER
AVIATION...BRAUN
FIRE WEATHER...BRAUN





000
FXUS65 KCYS 301809 AAA
AFDCYS

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE CHEYENNE WY
1208 PM MDT SAT AUG 30 2014

.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 335 AM MDT SAT AUG 30 2014

CURRENT IR SATELLITE LOOP SHOWS MOSTLY CLEAR SKIES OVER THE
FORECAST AREA AS THE NEXT BROAD UPPER LEVEL TROUGH IS CURRENTLY
PUSHING ACROSS THE PACIFIC NORTHWEST EARLY THIS MORNING. WITH
EASTERLY WINDS OVER THE HIGH PLAINS AND CLEAR SKIES...HAVE TO
MONITOR THE POTENTIAL OF SOME PATCHY FOG EARLY THIS MORNING.
OTHERWISE...A WARM AND PLEASANT DAY IS EXPECTED FOR THE BEGINNING
OF THE HOLIDAY WEEKEND AS HIGH TEMPERATURES INCREASE INTO THE
UPPER 70S TO UPPER 80S THIS AFTERNOON. WESTERN NEBRASKA LOCATIONS
WILL LIKELY SEE READINGS AROUND 90 DEGREES THIS AFTERNOON. THE
UPPER LEVEL TROUGH AND ASSOCIATED COLD FRONT ARE TRENDING A LITTLE
SLOWER COMPARED TO 24 HOURS AGO...WITH MODELS INDICATING THE FRONT
SLOWLY MOVING ACROSS NORTHWEST WYOMING TODAY. THUNDERSTORMS MAY BE
SLOW TO FORM...BUT EXPECT WIDELY SCATTERED SHOWERS AND TSTORMS
DEVELOPING FROM WEST TO EAST ACROSS THE AREA. MOST OF WESTERN
NEBRASKA WILL NOT SEE ANY CONVECTIVE ACTIVITY UNTIL THIS EVENING
DUE TO A WEAK CAP INVERSION AND DRIER AIR ALOFT. THIS FRONT WILL
EVENTUALLY ACCELERATE EASTWARD LATE TONIGHT RESULTING IN AT LEAST
ISOLATED SHOWERS AND TSTORMS AS A STRONGER THAN NORMAL 105 KT JET
MOVES OVER THE WYOMING/COLORADO BORDER.

EXPECT A COOLER THAN AVERAGE DAY ON SUNDAY BEHIND THE COLD FRONT
AS THE TROUGH AXIS MOVES ACROSS THE AREA AND 700MB TEMPERATURES
LOWER BETWEEN 4C TO 8C...RESULTING IN SURFACE TEMPERATURES IN THE
UPPER 60S TO MID 70S ACROSS MOST OF THE FORECAST AREA. WITH A
STRONG JET OVER THE AREA...BELIEVE MODELS ARE DOWNPLAYING THE
COVERAGE OF SHOWERS AND TSTORMS ON SUNDAY. INCREASED POP BETWEEN
25 TO 40 PERCENT ACROSS MOST OF THE REGION WITH SCATTERED SHOWERS
AND SOME THUNDER. WINDY CONDITIONS ARE EXPECTED THIS
WEEKEND...ESPECIALLY WEST OF THE LARAMIE RANGE WITH GUSTS UP TO 45
MPH POSSIBLE. SHOWER ACTIVITY WILL QUICKLY COME TO AN END SUNDAY
EVENING AS DRIER AIR AND MORE STABLE CONDITIONS MOVE OVER THE
FORECAST AREA.

ANOTHER COOL DAY EXPECTED ON MONDAY WITH HIGHS STRUGGLING TO REACH
THE LOW TO MID 70S ACROSS MOST OF THE AREA. THERE IS SOME MODEL
DISAGREEMENT DURING THE DAY WITH THE ECMWF SHOWING A SECONDARY
SHORTWAVE TROUGH QUICKLY MOVING OVER THE AREA. THE GFS...NAM AND
GEM EITHER SHOW THIS FEATURE FURTHER TO THE NORTH OR MUCH WEAKER
COMPARED TO THE ECMWF. KEPT A SLIGHT CHANCE OF SHOWERS IN THE
FORECAST FOR NOW...WITH POP AROUND 20 PERCENT ACROSS THE MOUNTAINS
AND HIGH PLAINS.

.LONG TERM...(MONDAY NIGHT THROUGH FRIDAY NIGHT)
ISSUED AT 300 AM MDT SAT AUG 30 2014

WARM...WINDY AND DRY WILL BE THE MAIN WEATHER STORY THROUGH MUCH
OF THE EXTENDED FORECAST PERIOD. MONDAY NIGHT WILL START OFF WITH
A FAST MOVING SHORTWAVE PUSHING EAST OF THE FORECAST AREA. THERE
MAY BE A FEW EVENING SHOWERS DEPENDING ON THE TIMING OF THE
SHORTWAVE... OTHERWISE A VAST MAJORITY OF THE AREA WILL BE DRY TUE
AND WED AS WESTERLY DOWNSLOPE FLOW KICKS IN ALONG WITH RIDGING
OVER THE WESTERN CONUS. WITH WARM AND DRY CONDITIONS IN PLACE
GUSTY WINDS WILL LIKELY PRODUCE CRITICAL FIRE WEATHER CONDITIONS.

QUESTIONS BEGIN TO ARISE THUR AND FRI AND EXTENDED MODELS DIVERGE.
GFS SHOWING A MUCH MORE PRONOUNCE TROUGH ACROSS THE FAR WESTERN
PORTIONS OF THE CONUS WITH A WEAK SHORTWAVE BRINGING MOISTURE INTO
SOUTHEAST WYOMING FOR THURSDAY. THE EC KEEPS WESTERLY FLOW WITH A
WEAK TROUGH DIGGING INTO THE NORTHWEST CONUS WHICH WOULD MEAN DRY
THROUGH THURSDAY.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY MORNING)
ISSUED AT 12 PM MDT SAT AUG 30 2014

SHORT TERM FORECAST TRENDS STILL SUGGEST THAT WE WILL SEE ISOLATED
SHOWERS AND THUNDERSTORMS FORMING IN THE HIGHER TERRAIN WEST OF
CHEYENNE IN THE MID AFTERNOON HOURS. LATEST HIGH RESOLUTION RAPID
REFRESH MODEL RUNS DEVELOP CONVECTION AROUND RAWLINS AND LARAMIE
AROUND 21Z...WORKING IT EASTWARD ACROSS THE CHEYENNE AREA MID TO LATE
AFTERNOON...THEN WEAKENING IT AS IT MOVES INTO THE MORE HIGHLY
CAPPED ATMOSPHERE OVER THE NEBRASKA PANHANDLE 00Z-03Z. HRRR
TIMING CLOSE TO OUR THINKING AS WELL ON TIMING FOR
SHOWERS/THUNDERSTORMS IN VICINITY OF EACH FORECAST LOCATION. DIDNT
MENTION VICINITY THUNDERSTORMS AT ALLIANCE AND SYDNEY DUE TO
GREATER CAP IN THE EAST. CEILINGS AND VISIBILITIES PREVAILING VFR
ALL PERIODS. COVERAGES OF SHOWERS AND STORMS NOT HIGH ENOUGH THIS
AFTERNOON AND EVENING FOR PREVAILING MENTION BELOW VFR CATEGORY.

&&

.FIRE WEATHER...
ISSUED AT 236 AM MDT SAT AUG 30 2014

NO SIGNIFICANT FIRE WEATHER CONCERNS THIS WEEKEND AND INTO EARLY
NEXT WEEK. A STRONG WEATHER DISTURBANCE AND ASSOCIATED COLD FRONT
WILL MOVE ACROSS THE AREA LATE TODAY THROUGH EARLY SUNDAY. SHOWERS
AND TSTORMS WILL DEVELOP FROM WEST TO EAST ACROSS SOUTHEAST WY
AND MOVE THE WESTERN NEBRASKA. GUSTY WEST TO SOUTHWEST WINDS ARE
EXPECTED ALONG AND WEST OF THE LARAMIE RANGE THIS WEEKEND WITH
GUSTS BETWEEN 30 TO 40 MPH. MINIMUM HUMIDITIES WILL REMAIN ABOVE
20 PERCENT HOWEVER INTO MONDAY WITH COOLER THAN NORMAL
TEMPERATURES.

&&

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

$$

SHORT TERM...TJT
LONG TERM...SML
AVIATION...GARMON
FIRE WEATHER...TJT







000
FXUS65 KCYS 301809 AAA
AFDCYS

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE CHEYENNE WY
1208 PM MDT SAT AUG 30 2014

.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 335 AM MDT SAT AUG 30 2014

CURRENT IR SATELLITE LOOP SHOWS MOSTLY CLEAR SKIES OVER THE
FORECAST AREA AS THE NEXT BROAD UPPER LEVEL TROUGH IS CURRENTLY
PUSHING ACROSS THE PACIFIC NORTHWEST EARLY THIS MORNING. WITH
EASTERLY WINDS OVER THE HIGH PLAINS AND CLEAR SKIES...HAVE TO
MONITOR THE POTENTIAL OF SOME PATCHY FOG EARLY THIS MORNING.
OTHERWISE...A WARM AND PLEASANT DAY IS EXPECTED FOR THE BEGINNING
OF THE HOLIDAY WEEKEND AS HIGH TEMPERATURES INCREASE INTO THE
UPPER 70S TO UPPER 80S THIS AFTERNOON. WESTERN NEBRASKA LOCATIONS
WILL LIKELY SEE READINGS AROUND 90 DEGREES THIS AFTERNOON. THE
UPPER LEVEL TROUGH AND ASSOCIATED COLD FRONT ARE TRENDING A LITTLE
SLOWER COMPARED TO 24 HOURS AGO...WITH MODELS INDICATING THE FRONT
SLOWLY MOVING ACROSS NORTHWEST WYOMING TODAY. THUNDERSTORMS MAY BE
SLOW TO FORM...BUT EXPECT WIDELY SCATTERED SHOWERS AND TSTORMS
DEVELOPING FROM WEST TO EAST ACROSS THE AREA. MOST OF WESTERN
NEBRASKA WILL NOT SEE ANY CONVECTIVE ACTIVITY UNTIL THIS EVENING
DUE TO A WEAK CAP INVERSION AND DRIER AIR ALOFT. THIS FRONT WILL
EVENTUALLY ACCELERATE EASTWARD LATE TONIGHT RESULTING IN AT LEAST
ISOLATED SHOWERS AND TSTORMS AS A STRONGER THAN NORMAL 105 KT JET
MOVES OVER THE WYOMING/COLORADO BORDER.

EXPECT A COOLER THAN AVERAGE DAY ON SUNDAY BEHIND THE COLD FRONT
AS THE TROUGH AXIS MOVES ACROSS THE AREA AND 700MB TEMPERATURES
LOWER BETWEEN 4C TO 8C...RESULTING IN SURFACE TEMPERATURES IN THE
UPPER 60S TO MID 70S ACROSS MOST OF THE FORECAST AREA. WITH A
STRONG JET OVER THE AREA...BELIEVE MODELS ARE DOWNPLAYING THE
COVERAGE OF SHOWERS AND TSTORMS ON SUNDAY. INCREASED POP BETWEEN
25 TO 40 PERCENT ACROSS MOST OF THE REGION WITH SCATTERED SHOWERS
AND SOME THUNDER. WINDY CONDITIONS ARE EXPECTED THIS
WEEKEND...ESPECIALLY WEST OF THE LARAMIE RANGE WITH GUSTS UP TO 45
MPH POSSIBLE. SHOWER ACTIVITY WILL QUICKLY COME TO AN END SUNDAY
EVENING AS DRIER AIR AND MORE STABLE CONDITIONS MOVE OVER THE
FORECAST AREA.

ANOTHER COOL DAY EXPECTED ON MONDAY WITH HIGHS STRUGGLING TO REACH
THE LOW TO MID 70S ACROSS MOST OF THE AREA. THERE IS SOME MODEL
DISAGREEMENT DURING THE DAY WITH THE ECMWF SHOWING A SECONDARY
SHORTWAVE TROUGH QUICKLY MOVING OVER THE AREA. THE GFS...NAM AND
GEM EITHER SHOW THIS FEATURE FURTHER TO THE NORTH OR MUCH WEAKER
COMPARED TO THE ECMWF. KEPT A SLIGHT CHANCE OF SHOWERS IN THE
FORECAST FOR NOW...WITH POP AROUND 20 PERCENT ACROSS THE MOUNTAINS
AND HIGH PLAINS.

.LONG TERM...(MONDAY NIGHT THROUGH FRIDAY NIGHT)
ISSUED AT 300 AM MDT SAT AUG 30 2014

WARM...WINDY AND DRY WILL BE THE MAIN WEATHER STORY THROUGH MUCH
OF THE EXTENDED FORECAST PERIOD. MONDAY NIGHT WILL START OFF WITH
A FAST MOVING SHORTWAVE PUSHING EAST OF THE FORECAST AREA. THERE
MAY BE A FEW EVENING SHOWERS DEPENDING ON THE TIMING OF THE
SHORTWAVE... OTHERWISE A VAST MAJORITY OF THE AREA WILL BE DRY TUE
AND WED AS WESTERLY DOWNSLOPE FLOW KICKS IN ALONG WITH RIDGING
OVER THE WESTERN CONUS. WITH WARM AND DRY CONDITIONS IN PLACE
GUSTY WINDS WILL LIKELY PRODUCE CRITICAL FIRE WEATHER CONDITIONS.

QUESTIONS BEGIN TO ARISE THUR AND FRI AND EXTENDED MODELS DIVERGE.
GFS SHOWING A MUCH MORE PRONOUNCE TROUGH ACROSS THE FAR WESTERN
PORTIONS OF THE CONUS WITH A WEAK SHORTWAVE BRINGING MOISTURE INTO
SOUTHEAST WYOMING FOR THURSDAY. THE EC KEEPS WESTERLY FLOW WITH A
WEAK TROUGH DIGGING INTO THE NORTHWEST CONUS WHICH WOULD MEAN DRY
THROUGH THURSDAY.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY MORNING)
ISSUED AT 12 PM MDT SAT AUG 30 2014

SHORT TERM FORECAST TRENDS STILL SUGGEST THAT WE WILL SEE ISOLATED
SHOWERS AND THUNDERSTORMS FORMING IN THE HIGHER TERRAIN WEST OF
CHEYENNE IN THE MID AFTERNOON HOURS. LATEST HIGH RESOLUTION RAPID
REFRESH MODEL RUNS DEVELOP CONVECTION AROUND RAWLINS AND LARAMIE
AROUND 21Z...WORKING IT EASTWARD ACROSS THE CHEYENNE AREA MID TO LATE
AFTERNOON...THEN WEAKENING IT AS IT MOVES INTO THE MORE HIGHLY
CAPPED ATMOSPHERE OVER THE NEBRASKA PANHANDLE 00Z-03Z. HRRR
TIMING CLOSE TO OUR THINKING AS WELL ON TIMING FOR
SHOWERS/THUNDERSTORMS IN VICINITY OF EACH FORECAST LOCATION. DIDNT
MENTION VICINITY THUNDERSTORMS AT ALLIANCE AND SYDNEY DUE TO
GREATER CAP IN THE EAST. CEILINGS AND VISIBILITIES PREVAILING VFR
ALL PERIODS. COVERAGES OF SHOWERS AND STORMS NOT HIGH ENOUGH THIS
AFTERNOON AND EVENING FOR PREVAILING MENTION BELOW VFR CATEGORY.

&&

.FIRE WEATHER...
ISSUED AT 236 AM MDT SAT AUG 30 2014

NO SIGNIFICANT FIRE WEATHER CONCERNS THIS WEEKEND AND INTO EARLY
NEXT WEEK. A STRONG WEATHER DISTURBANCE AND ASSOCIATED COLD FRONT
WILL MOVE ACROSS THE AREA LATE TODAY THROUGH EARLY SUNDAY. SHOWERS
AND TSTORMS WILL DEVELOP FROM WEST TO EAST ACROSS SOUTHEAST WY
AND MOVE THE WESTERN NEBRASKA. GUSTY WEST TO SOUTHWEST WINDS ARE
EXPECTED ALONG AND WEST OF THE LARAMIE RANGE THIS WEEKEND WITH
GUSTS BETWEEN 30 TO 40 MPH. MINIMUM HUMIDITIES WILL REMAIN ABOVE
20 PERCENT HOWEVER INTO MONDAY WITH COOLER THAN NORMAL
TEMPERATURES.

&&

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

$$

SHORT TERM...TJT
LONG TERM...SML
AVIATION...GARMON
FIRE WEATHER...TJT






000
FXUS63 KUNR 301720
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
1120 AM MDT SAT AUG 30 2014

.SHORT TERM...TODAY THROUGH SUNDAY NIGHT
ISSUED AT 313 AM MDT SAT AUG 30 2014

A LONGWAVE TROUGH IS CROSSING THE WRN CONUS...WITH UPPER RIDGING
OVER THE NRN PLAINS ATTM. SURFACE HIGH PRESSURE REMAINS IN CONTROL
OVER CNTRL CANADA TO THE NRN PLAINS. HIGH PRESSURE WILL SLIDE EWD
TODAY WITH STRONG RETURN FLOW SETTING UP OVER THE HIGH PLAINS.
BREEZY SE WINDS WILL SET UP ACROSS THE WRN SD PLAINS THROUGH THE
DAY. UPPER FLOW WILL BECOME MORE SWRLY AS THE UPPER TROUGH
APPROACHES FROM THE WEST...WITH A SURFACE LOW STRENGTHENING OVER
CNTRL/ERN MT. A STRONG UPPER WAVE OVER ID INTO THE GREAT BASIN WILL
MOVE E/NE THROUGH THE DAY BRINGING CHANCES FOR STORMS LATER THIS
AFTN INTO THE EVNG. THE DAY WILL START OFF QUIET WITH MOSTLY SUNNY
SKIES...THEN PRECIP DEVELOPING WEST OF THE CWA WILL BEING MOVING
INTO NE WY AND FAR WRN SD THIS AFTN. STRONG CAP WILL LIMIT STORM
DEVELOPMENT TO MAINLY IN THE LATE AFTN. SOME STORMS ARE EXPECTED TO
DEVELOP OVER THE BLKHLS BUT THINK THE NRN BLKHLS WILL HAVE THE
BETTER CHANCE OF PRECIP GIVEN THE BETTER ENVIRONMENT. SURFACE LOW
WILL CROSS THE NRN CWA INTO THE EVENING AS THE STRONG WAVE CROSSES
THE REGION...WITH A COLD FRONT PUSHING THROUGH TONIGHT. WITH
INCREASING SHEAR THIS EVENING OVER NE WY/NW SD...SOME SUPERCELL
DEVELOPMENT IS EXPECTED ESPECIALLY OVER NW SD WHERE MLCAPE IS
1000-1500 J/KG. STRONG WINDS AND LARGE HAIL WILL BE THE MAIN
THREATS. STORMS WILL END/PUSH EAST OF THE CWA LATER TONIGHT AS THE
UPPER WAVE CONTINUES TOWARD THE UPPER MIDWEST.

A QUICK BREAK IN PRECIP IS EXPECTED LATE TONIGHT...BUT THE NEXT
CHANCE OF SHOWERS/STORMS WILL BE SUNDAY MORNING AS THE MAIN TROUGH
AXIS APPROACHES. PRECIP WILL CROSS THE CWA THROUGH THE DAY SUNDAY
AS AN UPPER WAVE ROUNDS THE BASE OF THE TROUGH. HAVE INCREASED
POPS DURING THE DAYTIME HOURS. HAVE DROPPED TEMPS OVER NE WY AS
COLD AIR CONTINUES TO FILTER IN FROM THE W/NW. TEMPS OVER NE WY
SHOULD BE LIMITED TO THE 60S...WHILE WRN SD REACHES THE 70S.
PRECIP WILL END LATE SUNDAY OR SUNDAY EVENING AS THE TROUGH AXIS
PUSHES EAST OF THE CWA.

&&

.LONG TERM...MONDAY THROUGH FRIDAY
ISSUED AT 313 AM MDT SAT AUG 30 2014

SHORTWAVE IN CYCLONIC FLOW PASSES ACROSS THE NORTHERN PLAINS
MONDAY. WITH STEEP MID LEVEL LAPSE RATES...SCATTERED SHRA/TSRA
EXPECTED. UPPER TROF DIGS INTO THE PACIFIC NORTHWEST
TUE/WED...WITH FLAT RIDGE ACROSS THE NORTHERN PLAINS. THIS WILL
BRING DRY WEATHER AND ABOVE AVERAGE TEMPERATURES FOR MID WEEK.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY)
ISSUED AT 1118 AM MDT SAT AUG 30 2014

SCATTERED TSRA WILL DEVELOP ACROSS NORTHEAST WY THIS
AFTERNOON...SPREADING EAST ACROSS NORTHWEST SD THROUGH THIS
EVENING. ISOLATED -TSRA MAY DEVELOP OVER SOUTHWEST INTO SOUTH
CENTRAL SD THIS EVENING. IFR VSBYS EXPECTED WITH THE STRONGEST
STORMS ALONG WITH HAIL/GUSTY WINDS. OUTSIDE OF STORMS...VFR
CONDITIONS ARE EXPECTED.

&&

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

$$

SHORT TERM...13
LONG TERM...7
AVIATION...HELGESON




000
FXUS63 KUNR 301720
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
1120 AM MDT SAT AUG 30 2014

.SHORT TERM...TODAY THROUGH SUNDAY NIGHT
ISSUED AT 313 AM MDT SAT AUG 30 2014

A LONGWAVE TROUGH IS CROSSING THE WRN CONUS...WITH UPPER RIDGING
OVER THE NRN PLAINS ATTM. SURFACE HIGH PRESSURE REMAINS IN CONTROL
OVER CNTRL CANADA TO THE NRN PLAINS. HIGH PRESSURE WILL SLIDE EWD
TODAY WITH STRONG RETURN FLOW SETTING UP OVER THE HIGH PLAINS.
BREEZY SE WINDS WILL SET UP ACROSS THE WRN SD PLAINS THROUGH THE
DAY. UPPER FLOW WILL BECOME MORE SWRLY AS THE UPPER TROUGH
APPROACHES FROM THE WEST...WITH A SURFACE LOW STRENGTHENING OVER
CNTRL/ERN MT. A STRONG UPPER WAVE OVER ID INTO THE GREAT BASIN WILL
MOVE E/NE THROUGH THE DAY BRINGING CHANCES FOR STORMS LATER THIS
AFTN INTO THE EVNG. THE DAY WILL START OFF QUIET WITH MOSTLY SUNNY
SKIES...THEN PRECIP DEVELOPING WEST OF THE CWA WILL BEING MOVING
INTO NE WY AND FAR WRN SD THIS AFTN. STRONG CAP WILL LIMIT STORM
DEVELOPMENT TO MAINLY IN THE LATE AFTN. SOME STORMS ARE EXPECTED TO
DEVELOP OVER THE BLKHLS BUT THINK THE NRN BLKHLS WILL HAVE THE
BETTER CHANCE OF PRECIP GIVEN THE BETTER ENVIRONMENT. SURFACE LOW
WILL CROSS THE NRN CWA INTO THE EVENING AS THE STRONG WAVE CROSSES
THE REGION...WITH A COLD FRONT PUSHING THROUGH TONIGHT. WITH
INCREASING SHEAR THIS EVENING OVER NE WY/NW SD...SOME SUPERCELL
DEVELOPMENT IS EXPECTED ESPECIALLY OVER NW SD WHERE MLCAPE IS
1000-1500 J/KG. STRONG WINDS AND LARGE HAIL WILL BE THE MAIN
THREATS. STORMS WILL END/PUSH EAST OF THE CWA LATER TONIGHT AS THE
UPPER WAVE CONTINUES TOWARD THE UPPER MIDWEST.

A QUICK BREAK IN PRECIP IS EXPECTED LATE TONIGHT...BUT THE NEXT
CHANCE OF SHOWERS/STORMS WILL BE SUNDAY MORNING AS THE MAIN TROUGH
AXIS APPROACHES. PRECIP WILL CROSS THE CWA THROUGH THE DAY SUNDAY
AS AN UPPER WAVE ROUNDS THE BASE OF THE TROUGH. HAVE INCREASED
POPS DURING THE DAYTIME HOURS. HAVE DROPPED TEMPS OVER NE WY AS
COLD AIR CONTINUES TO FILTER IN FROM THE W/NW. TEMPS OVER NE WY
SHOULD BE LIMITED TO THE 60S...WHILE WRN SD REACHES THE 70S.
PRECIP WILL END LATE SUNDAY OR SUNDAY EVENING AS THE TROUGH AXIS
PUSHES EAST OF THE CWA.

&&

.LONG TERM...MONDAY THROUGH FRIDAY
ISSUED AT 313 AM MDT SAT AUG 30 2014

SHORTWAVE IN CYCLONIC FLOW PASSES ACROSS THE NORTHERN PLAINS
MONDAY. WITH STEEP MID LEVEL LAPSE RATES...SCATTERED SHRA/TSRA
EXPECTED. UPPER TROF DIGS INTO THE PACIFIC NORTHWEST
TUE/WED...WITH FLAT RIDGE ACROSS THE NORTHERN PLAINS. THIS WILL
BRING DRY WEATHER AND ABOVE AVERAGE TEMPERATURES FOR MID WEEK.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY)
ISSUED AT 1118 AM MDT SAT AUG 30 2014

SCATTERED TSRA WILL DEVELOP ACROSS NORTHEAST WY THIS
AFTERNOON...SPREADING EAST ACROSS NORTHWEST SD THROUGH THIS
EVENING. ISOLATED -TSRA MAY DEVELOP OVER SOUTHWEST INTO SOUTH
CENTRAL SD THIS EVENING. IFR VSBYS EXPECTED WITH THE STRONGEST
STORMS ALONG WITH HAIL/GUSTY WINDS. OUTSIDE OF STORMS...VFR
CONDITIONS ARE EXPECTED.

&&

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

$$

SHORT TERM...13
LONG TERM...7
AVIATION...HELGESON





000
FXUS65 KRIW 301705
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
1105 AM MDT SAT AUG 30 2014

.SHORT TERM...TODAY THROUGH MONDAY NIGHT

A BROAD DIGGING TROUGH ACROSS THE PACNW WILL CONTINUE TO MOVE
EAST...AFFECTING OUR WEATHER THROUGH SUNDAY NOW...PREVIOUS RUNS HAD
THE TROUGH MOVING THROUGH SOONER AND QUICKER WITHOUT MUCH OF A
REINFORCING SHOT ON SUNDAY...NOW IT LOOKS LIKE THERE WILL BE SEVERAL
WAVES AND REASONS TO KEEP SHOWERS AND STORMS GOING OFF AND ON INTO
SUNDAY EVENING. THERE WILL BE PLENTY GOING ON ALOFT TO SUSTAIN
SHOWERS AND STORMS WELL INTO THE NIGHT AS DIFLUENT FLOW AHEAD OF AN
APPROACHING JET MAX TRANSITIONS INTO THE LEFT EXIT REGION OF THE JET
DIPPING JUST TO OUR SOUTH BY SUNDAY EVENING...LEADING TO A SUSTAINED
PERIOD OF DYNAMIC LIFT ALOFT. THERE WILL ALSO BE SEVERAL WAVES OF QG
FORCING AND BROAD LIFT ASSOCIATED WITH EACH APPROACHING SHORT WAVE
TROUGH...THE FIRST OF WHICH WILL ARRIVE INTO THE WEST AROUND NOON
TODAY AND MOVING EAST THROUGH THE AFTERNOON. THE NEXT MORE POTENT
WAVE ACTUALLY ARRIVES LATE THIS EVENING INTO THE WEST BUT IS SLOWER
TO RAKE ACROSS THE FORECAST AREA...HANGING AROUND CENTRAL AND
EASTERN WYOMING THROUGH PEAK HEATING ON SUNDAY...KICKING OUT TO THE
NORTHEAST IN THE EVENING.

AT THE SURFACE...WE WILL HAVE A LOW DROPPING SOUTH OUT OF ALBERTA AT
A FAIRLY FAST CLIP...ARRIVING IN NORTHEAST WYOMING BY 18Z...SHARPLY
INCREASING THE SURFACE GRADIENT...WHICH WILL EASILY TAP INTO THE
SWIFT SOUTHWEST FLOW ALOFT LEADING TO A RATHER WINDY DAY ACROSS THE
FORECAST AREA...MOST NOTICEABLY ACROSS SWEETWATER COUNTY AND INTO
NATRONA COUNTY. THIS SOUTHWEST FLOW WILL DRAW UP SOME WARMER AND
DRIER AIR FROM THE SOUTHWESTERN U.S....BUT IN A RELATIVE
SENSE...THERE WILL BE PLENTY OF INSTABILITY AND MID LEVEL MOISTURE
TO WORK WITH FOR SOME THUNDERSTORM ACTIVITY THIS AFTERNOON AND
EVENING...HOWEVER THE STORMS ACROSS THE SOUTH WILL LIKELY PRODUCE
SOME STRONG WIND GUSTS. ELSEWHERE...THERE WILL BE SOME DECENT
INSTABILITY AND SHEAR ALONG AND BEHIND THE FRONT IN ADDITION TO SOME
LOWERING FREEZING LEVELS AND DECENT MID LEVEL INSTABILITY...WHICH
COULD LEAD TO SOME MORE ORGANIZED STORMS CAPABLE OF PRODUCING STRONG
TO SEVERE WIND GUSTS AND HAIL.

ALSO AT THE SURFACE...THE AFOREMENTIONED COLD FRONT WILL WORK ITS
WAY ACROSS THE AREA...ROUGHLY NORTHWEST TO SOUTHEAST BUT MOST OF IT
WILL BECOME HUNG UP ALONG THE DIVIDE UNTIL REINFORCEMENTS ARRIVE
LATE TONIGHT...COLD ENOUGH FOR MORE SNOW ABOVE 8500FT IN THE
NORTHERN MOUNTAINS. THERE WILL BE SOME DECENT INSTABILITY ALONG THE
FRONT...WITH CAPES ROUGHLY AROUND 1000 J/KG EVEN WELL INTO THE
NIGHT...WHICH COULD MAKE FOR QUITE THE LIGHT SHOW EAST OF THE DIVIDE
TONIGHT.

INCREASED PRECIPITATION CHANCES QUITE A BIT FOR SUNDAY AS THE MODELS
ARE ACTUALLY IN DECENT AGREEMENT ON KEEPING SHOWERS AND STORMS GOING
INTO SUNDAY EVENING. IT WILL DEFINITELY BE COOLER ACROSS THE
BOARD...AND WILL REMAIN BREEZY ACROSS THE SOUTH...SO THAT PART OF
THE FORECAST REMAINS UNCHANGED.

ON MONDAY...WE WILL BE IN THE COOLER BACK SIDE OF THE TROUGH WITH
LIGHTER NORTHWEST FLOW. THERE ARE SOME HINTS AT A DISTURBANCE TRYING
TO ZIP BY MONDAY LATE AFTERNOON SO SOME ISOLATED POPS WERE INCLUDED
FOR THE AFTERNOON BUT THE TIMING ON THIS COULD EASILY CHANGE BEFORE
THEN.

.LONG TERM...TUESDAY THROUGH SATURDAY

TUESDAY LOOKS DRY AND SEASONABLY WARM. WEDNESDAY APPEARS TO BE
MOSTLY DRY AS WELL AND WARMER...AFTERNOON BREEZE IN SOME PLACES.
SOME MID AND HIGH LEVEL MOISTURE MOVES IN WHICH WILL RESULT IN SOME
AFTERNOON CLOUDS. VERY ISOLATED SHOWERS/STORMS FOR THE MOUNTAINS WED
PM AND EARLY EVE. THE WEATHER PATTERN GETS MORE ACTIVE NEXT THURSDAY
THROUGH NEXT SATURDAY. A SOUTHWEST FLOW ALOFT WITH A TROUGH OF LOW
PRESSURE OVER THE PACIFIC NW EXTENDING TO THE NORTHERN U.S AND AN
UPPER HIGH OVER THE SW DESERT STATES INTO THE SOUTHERN PLAINS. THE
GFS MODEL GRADUALLY SAGS THE TROUGH TOWARD NORTHERN WY THURSDAY
THROUGH SATURDAY. THE ECMWF MODEL SWINGS THE TROUGH ACROSS
NORTHERN WY THURSDAY PM AND NIGHT. IT THEN LEAVES MOISTURE AROUND
FRIDAY AND NEXT SATURDAY WITH WEAK DISTURBANCES NEARBY. ON
THURSDAY THE BEST CHANCE OF SHOWERS AND STORMS WILL BE OVER THE NW
THIRD...SAY FROM AFTON TO BUFFALO LINE. ISOLATED OR NOTHING SOUTH
OF THIS LINE. ON FRIDAY AND SATURDAY THE WHOLE REGION COULD SEE A
SHOWER OR STORM WITH THE BETTER CHANCES OVER AND NEAR THE
MOUNTAINS AND OVER THE NORTH WHERE THE TROUGH IS CLOSEST. A COLD
FRONT IS FORECAST TO MOVE INTO THE NORTH THURSDAY AND THIS FRONT
MOVES SOUTH THURSDAY NIGHT INTO FRIDAY. BEST COOLING OVER THE
NORTH THURSDAY AND BEST COOLING OVER THE NORTH AND CENTRAL FRIDAY.
SLIGHT MODERATION OF TEMPS NEXT SATURDAY.

&&

.AVIATION.../18Z ISSUANCE/

AN EVOLVING LARGE UPPER LEVEL TROUGH WITH SEVERAL EMBEDDED
DISTURBANCES WILL PUSH ACROSS THE FORECAST AREA THROUGH THE FORECAST
PERIOD. THIS SYSTEM WILL DESTABILIZE THE ATMOSPHERE AND PUSH A
COUPLE OF COLD FRONTS SOUTH ACROSS NORTH AND CENTRAL WYOMING THIS
AFTERNOON AND AGAIN SUNDAY MORNING. THESE BOUNDARIES WILL BE THE
FOCUS FOR STRONGER THUNDERSTORMS THIS AFTERNOON...PRIMARILY VCNTY
AND NORTH OF A KDUB-KWRL-50SM S KBYG LINE. THESE STORMS WILL BE
MOVING AT A GOOD CLIP...AROUND 35 TO 40 KTS...WITH SOME OF THESE
STORMS CAPABLE OF MARGINALLY SEVERE HAIL AND WIND GUSTS WITH BRIEF
MVFR/IFR CONDITIONS. SOUTH OF THE FRONT(S)...WSW WINDS AT 20-30KTS
WILL PREVAIL IN THE AFTERNOON ALONG WITH ISOLATED TO WIDELY SCT
THUNDERSTORMS. THE MAIN HAZARD WITH THESE STORMS WILL BE ERRATIC
OUTFLOW WIND GUSTS NEAR 45KTS. MOST OF THIS ACTIVITY WILL MOVE EAST
INTO THE HIGH PLAINS THIS EVENING.  THE BACK SIDE OF THIS TROUGH
WILL PUSH INTO WESTERN WYOMING EARLY SUNDAY MORNING SPREADING
SCT-NMRS SHRA/ISOLD TSRA AND HIGHER MTN OBSCURATIONS ACROSS THE
STATE...BUT PRIMARILY VCNTY AND N OF A KJAC-KLND-KCPR LINE.

&&

.FIRE WEATHER...

SEVERAL WAVES OF SHOWERS AND THUNDERSTORMS ARE EXPECTED DURING THE
NEXT 48 HOURS...WITH INCREASING SOUTHWEST WIND AHEAD OF IT TODAY AND
PERSISTING INTO SUNDAY. THERE WILL BE ELEVATED FIRE WEATHER
CONDITIONS IN THE SWEETWATER...FREMONT...NATRONA AND SOUTHERN
JOHNSON COUNTIES AHEAD OF THE COLD FRONT DUE TO STRONG SOUTHWEST
WIND OF 25 TO 40 MPH WITH A BRIEF PERIOD WHEN RH`S MAY DROP INTO THE
UPPER TEENS TO LOW 20S. HOWEVER...THE COLD FRONT AND EVEN SOME
SHOWERS WILL MOVE INTO THE CENTRAL PART OF THE AREA BY LATE MORNING
TO AROUND NOON WITH HIGHER RH`S AND SOME SHOWER AND ISOLATED
THUNDERSTORM ACTIVITY. OTHER AREAS WILL HAVE HIGHER RH`S BUT STILL A
PERIOD WINDY CONDITIONS AND SOME THUNDERSTORMS.

&&

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

&&

$$

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








000
FXUS65 KRIW 301705
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
1105 AM MDT SAT AUG 30 2014

.SHORT TERM...TODAY THROUGH MONDAY NIGHT

A BROAD DIGGING TROUGH ACROSS THE PACNW WILL CONTINUE TO MOVE
EAST...AFFECTING OUR WEATHER THROUGH SUNDAY NOW...PREVIOUS RUNS HAD
THE TROUGH MOVING THROUGH SOONER AND QUICKER WITHOUT MUCH OF A
REINFORCING SHOT ON SUNDAY...NOW IT LOOKS LIKE THERE WILL BE SEVERAL
WAVES AND REASONS TO KEEP SHOWERS AND STORMS GOING OFF AND ON INTO
SUNDAY EVENING. THERE WILL BE PLENTY GOING ON ALOFT TO SUSTAIN
SHOWERS AND STORMS WELL INTO THE NIGHT AS DIFLUENT FLOW AHEAD OF AN
APPROACHING JET MAX TRANSITIONS INTO THE LEFT EXIT REGION OF THE JET
DIPPING JUST TO OUR SOUTH BY SUNDAY EVENING...LEADING TO A SUSTAINED
PERIOD OF DYNAMIC LIFT ALOFT. THERE WILL ALSO BE SEVERAL WAVES OF QG
FORCING AND BROAD LIFT ASSOCIATED WITH EACH APPROACHING SHORT WAVE
TROUGH...THE FIRST OF WHICH WILL ARRIVE INTO THE WEST AROUND NOON
TODAY AND MOVING EAST THROUGH THE AFTERNOON. THE NEXT MORE POTENT
WAVE ACTUALLY ARRIVES LATE THIS EVENING INTO THE WEST BUT IS SLOWER
TO RAKE ACROSS THE FORECAST AREA...HANGING AROUND CENTRAL AND
EASTERN WYOMING THROUGH PEAK HEATING ON SUNDAY...KICKING OUT TO THE
NORTHEAST IN THE EVENING.

AT THE SURFACE...WE WILL HAVE A LOW DROPPING SOUTH OUT OF ALBERTA AT
A FAIRLY FAST CLIP...ARRIVING IN NORTHEAST WYOMING BY 18Z...SHARPLY
INCREASING THE SURFACE GRADIENT...WHICH WILL EASILY TAP INTO THE
SWIFT SOUTHWEST FLOW ALOFT LEADING TO A RATHER WINDY DAY ACROSS THE
FORECAST AREA...MOST NOTICEABLY ACROSS SWEETWATER COUNTY AND INTO
NATRONA COUNTY. THIS SOUTHWEST FLOW WILL DRAW UP SOME WARMER AND
DRIER AIR FROM THE SOUTHWESTERN U.S....BUT IN A RELATIVE
SENSE...THERE WILL BE PLENTY OF INSTABILITY AND MID LEVEL MOISTURE
TO WORK WITH FOR SOME THUNDERSTORM ACTIVITY THIS AFTERNOON AND
EVENING...HOWEVER THE STORMS ACROSS THE SOUTH WILL LIKELY PRODUCE
SOME STRONG WIND GUSTS. ELSEWHERE...THERE WILL BE SOME DECENT
INSTABILITY AND SHEAR ALONG AND BEHIND THE FRONT IN ADDITION TO SOME
LOWERING FREEZING LEVELS AND DECENT MID LEVEL INSTABILITY...WHICH
COULD LEAD TO SOME MORE ORGANIZED STORMS CAPABLE OF PRODUCING STRONG
TO SEVERE WIND GUSTS AND HAIL.

ALSO AT THE SURFACE...THE AFOREMENTIONED COLD FRONT WILL WORK ITS
WAY ACROSS THE AREA...ROUGHLY NORTHWEST TO SOUTHEAST BUT MOST OF IT
WILL BECOME HUNG UP ALONG THE DIVIDE UNTIL REINFORCEMENTS ARRIVE
LATE TONIGHT...COLD ENOUGH FOR MORE SNOW ABOVE 8500FT IN THE
NORTHERN MOUNTAINS. THERE WILL BE SOME DECENT INSTABILITY ALONG THE
FRONT...WITH CAPES ROUGHLY AROUND 1000 J/KG EVEN WELL INTO THE
NIGHT...WHICH COULD MAKE FOR QUITE THE LIGHT SHOW EAST OF THE DIVIDE
TONIGHT.

INCREASED PRECIPITATION CHANCES QUITE A BIT FOR SUNDAY AS THE MODELS
ARE ACTUALLY IN DECENT AGREEMENT ON KEEPING SHOWERS AND STORMS GOING
INTO SUNDAY EVENING. IT WILL DEFINITELY BE COOLER ACROSS THE
BOARD...AND WILL REMAIN BREEZY ACROSS THE SOUTH...SO THAT PART OF
THE FORECAST REMAINS UNCHANGED.

ON MONDAY...WE WILL BE IN THE COOLER BACK SIDE OF THE TROUGH WITH
LIGHTER NORTHWEST FLOW. THERE ARE SOME HINTS AT A DISTURBANCE TRYING
TO ZIP BY MONDAY LATE AFTERNOON SO SOME ISOLATED POPS WERE INCLUDED
FOR THE AFTERNOON BUT THE TIMING ON THIS COULD EASILY CHANGE BEFORE
THEN.

.LONG TERM...TUESDAY THROUGH SATURDAY

TUESDAY LOOKS DRY AND SEASONABLY WARM. WEDNESDAY APPEARS TO BE
MOSTLY DRY AS WELL AND WARMER...AFTERNOON BREEZE IN SOME PLACES.
SOME MID AND HIGH LEVEL MOISTURE MOVES IN WHICH WILL RESULT IN SOME
AFTERNOON CLOUDS. VERY ISOLATED SHOWERS/STORMS FOR THE MOUNTAINS WED
PM AND EARLY EVE. THE WEATHER PATTERN GETS MORE ACTIVE NEXT THURSDAY
THROUGH NEXT SATURDAY. A SOUTHWEST FLOW ALOFT WITH A TROUGH OF LOW
PRESSURE OVER THE PACIFIC NW EXTENDING TO THE NORTHERN U.S AND AN
UPPER HIGH OVER THE SW DESERT STATES INTO THE SOUTHERN PLAINS. THE
GFS MODEL GRADUALLY SAGS THE TROUGH TOWARD NORTHERN WY THURSDAY
THROUGH SATURDAY. THE ECMWF MODEL SWINGS THE TROUGH ACROSS
NORTHERN WY THURSDAY PM AND NIGHT. IT THEN LEAVES MOISTURE AROUND
FRIDAY AND NEXT SATURDAY WITH WEAK DISTURBANCES NEARBY. ON
THURSDAY THE BEST CHANCE OF SHOWERS AND STORMS WILL BE OVER THE NW
THIRD...SAY FROM AFTON TO BUFFALO LINE. ISOLATED OR NOTHING SOUTH
OF THIS LINE. ON FRIDAY AND SATURDAY THE WHOLE REGION COULD SEE A
SHOWER OR STORM WITH THE BETTER CHANCES OVER AND NEAR THE
MOUNTAINS AND OVER THE NORTH WHERE THE TROUGH IS CLOSEST. A COLD
FRONT IS FORECAST TO MOVE INTO THE NORTH THURSDAY AND THIS FRONT
MOVES SOUTH THURSDAY NIGHT INTO FRIDAY. BEST COOLING OVER THE
NORTH THURSDAY AND BEST COOLING OVER THE NORTH AND CENTRAL FRIDAY.
SLIGHT MODERATION OF TEMPS NEXT SATURDAY.

&&

.AVIATION.../18Z ISSUANCE/

AN EVOLVING LARGE UPPER LEVEL TROUGH WITH SEVERAL EMBEDDED
DISTURBANCES WILL PUSH ACROSS THE FORECAST AREA THROUGH THE FORECAST
PERIOD. THIS SYSTEM WILL DESTABILIZE THE ATMOSPHERE AND PUSH A
COUPLE OF COLD FRONTS SOUTH ACROSS NORTH AND CENTRAL WYOMING THIS
AFTERNOON AND AGAIN SUNDAY MORNING. THESE BOUNDARIES WILL BE THE
FOCUS FOR STRONGER THUNDERSTORMS THIS AFTERNOON...PRIMARILY VCNTY
AND NORTH OF A KDUB-KWRL-50SM S KBYG LINE. THESE STORMS WILL BE
MOVING AT A GOOD CLIP...AROUND 35 TO 40 KTS...WITH SOME OF THESE
STORMS CAPABLE OF MARGINALLY SEVERE HAIL AND WIND GUSTS WITH BRIEF
MVFR/IFR CONDITIONS. SOUTH OF THE FRONT(S)...WSW WINDS AT 20-30KTS
WILL PREVAIL IN THE AFTERNOON ALONG WITH ISOLATED TO WIDELY SCT
THUNDERSTORMS. THE MAIN HAZARD WITH THESE STORMS WILL BE ERRATIC
OUTFLOW WIND GUSTS NEAR 45KTS. MOST OF THIS ACTIVITY WILL MOVE EAST
INTO THE HIGH PLAINS THIS EVENING.  THE BACK SIDE OF THIS TROUGH
WILL PUSH INTO WESTERN WYOMING EARLY SUNDAY MORNING SPREADING
SCT-NMRS SHRA/ISOLD TSRA AND HIGHER MTN OBSCURATIONS ACROSS THE
STATE...BUT PRIMARILY VCNTY AND N OF A KJAC-KLND-KCPR LINE.

&&

.FIRE WEATHER...

SEVERAL WAVES OF SHOWERS AND THUNDERSTORMS ARE EXPECTED DURING THE
NEXT 48 HOURS...WITH INCREASING SOUTHWEST WIND AHEAD OF IT TODAY AND
PERSISTING INTO SUNDAY. THERE WILL BE ELEVATED FIRE WEATHER
CONDITIONS IN THE SWEETWATER...FREMONT...NATRONA AND SOUTHERN
JOHNSON COUNTIES AHEAD OF THE COLD FRONT DUE TO STRONG SOUTHWEST
WIND OF 25 TO 40 MPH WITH A BRIEF PERIOD WHEN RH`S MAY DROP INTO THE
UPPER TEENS TO LOW 20S. HOWEVER...THE COLD FRONT AND EVEN SOME
SHOWERS WILL MOVE INTO THE CENTRAL PART OF THE AREA BY LATE MORNING
TO AROUND NOON WITH HIGHER RH`S AND SOME SHOWER AND ISOLATED
THUNDERSTORM ACTIVITY. OTHER AREAS WILL HAVE HIGHER RH`S BUT STILL A
PERIOD WINDY CONDITIONS AND SOME THUNDERSTORMS.

&&

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

&&

$$

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







000
FXUS65 KCYS 301220
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
620 AM MDT SAT AUG 30 2014

.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 335 AM MDT SAT AUG 30 2014

CURRENT IR SATELLITE LOOP SHOWS MOSTLY CLEAR SKIES OVER THE
FORECAST AREA AS THE NEXT BROAD UPPER LEVEL TROUGH IS CURRENTLY
PUSHING ACROSS THE PACIFIC NORTHWEST EARLY THIS MORNING. WITH
EASTERLY WINDS OVER THE HIGH PLAINS AND CLEAR SKIES...HAVE TO
MONITOR THE POTENTIAL OF SOME PATCHY FOG EARLY THIS MORNING.
OTHERWISE...A WARM AND PLEASANT DAY IS EXPECTED FOR THE BEGINNING
OF THE HOLIDAY WEEKEND AS HIGH TEMPERATURES INCREASE INTO THE
UPPER 70S TO UPPER 80S THIS AFTERNOON. WESTERN NEBRASKA LOCATIONS
WILL LIKELY SEE READINGS AROUND 90 DEGREES THIS AFTERNOON. THE
UPPER LEVEL TROUGH AND ASSOCIATED COLD FRONT ARE TRENDING A LITTLE
SLOWER COMPARED TO 24 HOURS AGO...WITH MODELS INDICATING THE FRONT
SLOWLY MOVING ACROSS NORTHWEST WYOMING TODAY. THUNDERSTORMS MAY BE
SLOW TO FORM...BUT EXPECT WIDELY SCATTERED SHOWERS AND TSTORMS
DEVELOPING FROM WEST TO EAST ACROSS THE AREA. MOST OF WESTERN
NEBRASKA WILL NOT SEE ANY CONVECTIVE ACTIVITY UNTIL THIS EVENING
DUE TO A WEAK CAP INVERSION AND DRIER AIR ALOFT. THIS FRONT WILL
EVENTUALLY ACCELERATE EASTWARD LATE TONIGHT RESULTING IN AT LEAST
ISOLATED SHOWERS AND TSTORMS AS A STRONGER THAN NORMAL 105 KT JET
MOVES OVER THE WYOMING/COLORADO BORDER.

EXPECT A COOLER THAN AVERAGE DAY ON SUNDAY BEHIND THE COLD FRONT
AS THE TROUGH AXIS MOVES ACROSS THE AREA AND 700MB TEMPERATURES
LOWER BETWEEN 4C TO 8C...RESULTING IN SURFACE TEMPERATURES IN THE
UPPER 60S TO MID 70S ACROSS MOST OF THE FORECAST AREA. WITH A
STRONG JET OVER THE AREA...BELIEVE MODELS ARE DOWNPLAYING THE
COVERAGE OF SHOWERS AND TSTORMS ON SUNDAY. INCREASED POP BETWEEN
25 TO 40 PERCENT ACROSS MOST OF THE REGION WITH SCATTERED SHOWERS
AND SOME THUNDER. WINDY CONDITIONS ARE EXPECTED THIS
WEEKEND...ESPECIALLY WEST OF THE LARAMIE RANGE WITH GUSTS UP TO 45
MPH POSSIBLE. SHOWER ACTIVITY WILL QUICKLY COME TO AN END SUNDAY
EVENING AS DRIER AIR AND MORE STABLE CONDITIONS MOVE OVER THE
FORECAST AREA.

ANOTHER COOL DAY EXPECTED ON MONDAY WITH HIGHS STRUGGLING TO REACH
THE LOW TO MID 70S ACROSS MOST OF THE AREA. THERE IS SOME MODEL
DISAGREEMENT DURING THE DAY WITH THE ECMWF SHOWING A SECONDARY
SHORTWAVE TROUGH QUICKLY MOVING OVER THE AREA. THE GFS...NAM AND
GEM EITHER SHOW THIS FEATURE FURTHER TO THE NORTH OR MUCH WEAKER
COMPARED TO THE ECMWF. KEPT A SLIGHT CHANCE OF SHOWERS IN THE
FORECAST FOR NOW...WITH POP AROUND 20 PERCENT ACROSS THE MOUNTAINS
AND HIGH PLAINS.

.LONG TERM...(MONDAY NIGHT THROUGH FRIDAY NIGHT)
ISSUED AT 300 AM MDT SAT AUG 30 2014

WARM...WINDY AND DRY WILL BE THE MAIN WEATHER STORY THROUGH MUCH
OF THE EXTENDED FORECAST PERIOD. MONDAY NIGHT WILL START OFF WITH
A FAST MOVING SHORTWAVE PUSHING EAST OF THE FORECAST AREA. THERE
MAY BE A FEW EVENING SHOWERS DEPENDING ON THE TIMING OF THE
SHORTWAVE... OTHERWISE A VAST MAJORITY OF THE AREA WILL BE DRY TUE
AND WED AS WESTERLY DOWNSLOPE FLOW KICKS IN ALONG WITH RIDGING
OVER THE WESTERN CONUS. WITH WARM AND DRY CONDITIONS IN PLACE
GUSTY WINDS WILL LIKELY PRODUCE CRITICAL FIRE WEATHER CONDITIONS.

QUESTIONS BEGIN TO ARISE THUR AND FRI AND EXTENDED MODELS DIVERGE.
GFS SHOWING A MUCH MORE PRONOUNCE TROUGH ACROSS THE FAR WESTERN
PORTIONS OF THE CONUS WITH A WEAK SHORTWAVE BRINGING MOISTURE INTO
SOUTHEAST WYOMING FOR THURSDAY. THE EC KEEPS WESTERLY FLOW WITH A
WEAK TROUGH DIGGING INTO THE NORTHWEST CONUS WHICH WOULD MEAN DRY
THROUGH THURSDAY.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 619 AM MDT SAT AUG 30 2014

LIGHT WINDS AND CLEAR SKIES TO START OFF SATURDAY MORNING. THIS
WILL CHANGE THIS AFTERNOON AS GUSTY WEST WINDS
DEVELOP...ESPECIALLY6Y EAST OF THE LARAMIE RANGE WHERE GUSTS TO 40
MPH WILL OCCUR. THUNDERSTORMS WILL ALSO DEVELOP OVER THE
MOUNTAINS IN SOUTHEAST WYOMING BY EARLY THIS AFTERNOON...SOME
THUNDERSTORMS WILL MOVE EAST INTO THE PLAINS INCLUDING PORTIONS OF
THE NEBRASKA PANHANDLE.

&&

.FIRE WEATHER...
ISSUED AT 236 AM MDT SAT AUG 30 2014

NO SIGNIFICANT FIRE WEATHER CONCERNS THIS WEEKEND AND INTO EARLY
NEXT WEEK. A STRONG WEATHER DISTURBANCE AND ASSOCIATED COLD FRONT
WILL MOVE ACROSS THE AREA LATE TODAY THROUGH EARLY SUNDAY. SHOWERS
AND TSTORMS WILL DEVELOP FROM WEST TO EAST ACROSS SOUTHEAST WY
AND MOVE THE WESTERN NEBRASKA. GUSTY WEST TO SOUTHWEST WINDS ARE
EXPECTED ALONG AND WEST OF THE LARAMIE RANGE THIS WEEKEND WITH
GUSTS BETWEEN 30 TO 40 MPH. MINIMUM HUMIDITIES WILL REMAIN ABOVE
20 PERCENT HOWEVER INTO MONDAY WITH COOLER THAN NORMAL
TEMPERATURES.

&&

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

&&

$$

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







000
FXUS65 KCYS 301220
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
620 AM MDT SAT AUG 30 2014

.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 335 AM MDT SAT AUG 30 2014

CURRENT IR SATELLITE LOOP SHOWS MOSTLY CLEAR SKIES OVER THE
FORECAST AREA AS THE NEXT BROAD UPPER LEVEL TROUGH IS CURRENTLY
PUSHING ACROSS THE PACIFIC NORTHWEST EARLY THIS MORNING. WITH
EASTERLY WINDS OVER THE HIGH PLAINS AND CLEAR SKIES...HAVE TO
MONITOR THE POTENTIAL OF SOME PATCHY FOG EARLY THIS MORNING.
OTHERWISE...A WARM AND PLEASANT DAY IS EXPECTED FOR THE BEGINNING
OF THE HOLIDAY WEEKEND AS HIGH TEMPERATURES INCREASE INTO THE
UPPER 70S TO UPPER 80S THIS AFTERNOON. WESTERN NEBRASKA LOCATIONS
WILL LIKELY SEE READINGS AROUND 90 DEGREES THIS AFTERNOON. THE
UPPER LEVEL TROUGH AND ASSOCIATED COLD FRONT ARE TRENDING A LITTLE
SLOWER COMPARED TO 24 HOURS AGO...WITH MODELS INDICATING THE FRONT
SLOWLY MOVING ACROSS NORTHWEST WYOMING TODAY. THUNDERSTORMS MAY BE
SLOW TO FORM...BUT EXPECT WIDELY SCATTERED SHOWERS AND TSTORMS
DEVELOPING FROM WEST TO EAST ACROSS THE AREA. MOST OF WESTERN
NEBRASKA WILL NOT SEE ANY CONVECTIVE ACTIVITY UNTIL THIS EVENING
DUE TO A WEAK CAP INVERSION AND DRIER AIR ALOFT. THIS FRONT WILL
EVENTUALLY ACCELERATE EASTWARD LATE TONIGHT RESULTING IN AT LEAST
ISOLATED SHOWERS AND TSTORMS AS A STRONGER THAN NORMAL 105 KT JET
MOVES OVER THE WYOMING/COLORADO BORDER.

EXPECT A COOLER THAN AVERAGE DAY ON SUNDAY BEHIND THE COLD FRONT
AS THE TROUGH AXIS MOVES ACROSS THE AREA AND 700MB TEMPERATURES
LOWER BETWEEN 4C TO 8C...RESULTING IN SURFACE TEMPERATURES IN THE
UPPER 60S TO MID 70S ACROSS MOST OF THE FORECAST AREA. WITH A
STRONG JET OVER THE AREA...BELIEVE MODELS ARE DOWNPLAYING THE
COVERAGE OF SHOWERS AND TSTORMS ON SUNDAY. INCREASED POP BETWEEN
25 TO 40 PERCENT ACROSS MOST OF THE REGION WITH SCATTERED SHOWERS
AND SOME THUNDER. WINDY CONDITIONS ARE EXPECTED THIS
WEEKEND...ESPECIALLY WEST OF THE LARAMIE RANGE WITH GUSTS UP TO 45
MPH POSSIBLE. SHOWER ACTIVITY WILL QUICKLY COME TO AN END SUNDAY
EVENING AS DRIER AIR AND MORE STABLE CONDITIONS MOVE OVER THE
FORECAST AREA.

ANOTHER COOL DAY EXPECTED ON MONDAY WITH HIGHS STRUGGLING TO REACH
THE LOW TO MID 70S ACROSS MOST OF THE AREA. THERE IS SOME MODEL
DISAGREEMENT DURING THE DAY WITH THE ECMWF SHOWING A SECONDARY
SHORTWAVE TROUGH QUICKLY MOVING OVER THE AREA. THE GFS...NAM AND
GEM EITHER SHOW THIS FEATURE FURTHER TO THE NORTH OR MUCH WEAKER
COMPARED TO THE ECMWF. KEPT A SLIGHT CHANCE OF SHOWERS IN THE
FORECAST FOR NOW...WITH POP AROUND 20 PERCENT ACROSS THE MOUNTAINS
AND HIGH PLAINS.

.LONG TERM...(MONDAY NIGHT THROUGH FRIDAY NIGHT)
ISSUED AT 300 AM MDT SAT AUG 30 2014

WARM...WINDY AND DRY WILL BE THE MAIN WEATHER STORY THROUGH MUCH
OF THE EXTENDED FORECAST PERIOD. MONDAY NIGHT WILL START OFF WITH
A FAST MOVING SHORTWAVE PUSHING EAST OF THE FORECAST AREA. THERE
MAY BE A FEW EVENING SHOWERS DEPENDING ON THE TIMING OF THE
SHORTWAVE... OTHERWISE A VAST MAJORITY OF THE AREA WILL BE DRY TUE
AND WED AS WESTERLY DOWNSLOPE FLOW KICKS IN ALONG WITH RIDGING
OVER THE WESTERN CONUS. WITH WARM AND DRY CONDITIONS IN PLACE
GUSTY WINDS WILL LIKELY PRODUCE CRITICAL FIRE WEATHER CONDITIONS.

QUESTIONS BEGIN TO ARISE THUR AND FRI AND EXTENDED MODELS DIVERGE.
GFS SHOWING A MUCH MORE PRONOUNCE TROUGH ACROSS THE FAR WESTERN
PORTIONS OF THE CONUS WITH A WEAK SHORTWAVE BRINGING MOISTURE INTO
SOUTHEAST WYOMING FOR THURSDAY. THE EC KEEPS WESTERLY FLOW WITH A
WEAK TROUGH DIGGING INTO THE NORTHWEST CONUS WHICH WOULD MEAN DRY
THROUGH THURSDAY.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 619 AM MDT SAT AUG 30 2014

LIGHT WINDS AND CLEAR SKIES TO START OFF SATURDAY MORNING. THIS
WILL CHANGE THIS AFTERNOON AS GUSTY WEST WINDS
DEVELOP...ESPECIALLY6Y EAST OF THE LARAMIE RANGE WHERE GUSTS TO 40
MPH WILL OCCUR. THUNDERSTORMS WILL ALSO DEVELOP OVER THE
MOUNTAINS IN SOUTHEAST WYOMING BY EARLY THIS AFTERNOON...SOME
THUNDERSTORMS WILL MOVE EAST INTO THE PLAINS INCLUDING PORTIONS OF
THE NEBRASKA PANHANDLE.

&&

.FIRE WEATHER...
ISSUED AT 236 AM MDT SAT AUG 30 2014

NO SIGNIFICANT FIRE WEATHER CONCERNS THIS WEEKEND AND INTO EARLY
NEXT WEEK. A STRONG WEATHER DISTURBANCE AND ASSOCIATED COLD FRONT
WILL MOVE ACROSS THE AREA LATE TODAY THROUGH EARLY SUNDAY. SHOWERS
AND TSTORMS WILL DEVELOP FROM WEST TO EAST ACROSS SOUTHEAST WY
AND MOVE THE WESTERN NEBRASKA. GUSTY WEST TO SOUTHWEST WINDS ARE
EXPECTED ALONG AND WEST OF THE LARAMIE RANGE THIS WEEKEND WITH
GUSTS BETWEEN 30 TO 40 MPH. MINIMUM HUMIDITIES WILL REMAIN ABOVE
20 PERCENT HOWEVER INTO MONDAY WITH COOLER THAN NORMAL
TEMPERATURES.

&&

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

&&

$$

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






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