Area Forecast Discussion
Issued by NWS Cheyenne, WY

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000
FXUS65 KCYS 031754
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
1045 AM MST WED FEB 3 2016

.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 400 AM MST WED FEB 3 2016

FORECAST CHALLENGES DEAL WITH WIND SPEEDS AND BLOWING SNOW.
CURRENTLY...INFRARED SATELLITE SHOWING SOME COLD CLOUD TOPS
PUSHING INTO SOUTHWESTERN AND SOUTH CENTRAL WYOMING THIS MORNING.
THIS ASSOCIATED WITH A WEAK SHORTWAVE BEING SEEN ON WATER VAPOR
IMAGERY. SOME LIGHT SNOW STILL BEING REPORTED OUT BY ELK MOUNTAIN
AND IN THE NEBRASKA PANHANDLE...BUT OVERALL...CONDITIONS ARE
MAINLY DRY.

WE ARE GOING TO START OFF THE DAY WITH FAIRLY LIGHT WINDS...BUT
GUIDANCE IS SHOWING A FAIRLY SHARP UPTICK IN WINDS THIS EVENING.
GFS 700MB WINDS INCREASING TO 60KTS AFTER 06Z TONIGHT. CRAIG TO
CASPER 850/700MB HEIGHT GRADIENTS FROM THE NAM INCREASE TO NEAR
60MTRS AFTER 03Z TONIGHT. GFS 700MB HEIGHT GRADIENTS SLIGHTLY
HIGHER AT 70MTRS. DOES LOOK LIKE A GOOD WIND EVENT AT LEAST FOR
OUR WIND PRONE AREAS.

WITH RECENT SNOW FALL...LOOK FOR AN INCREASE IN BLOWING SNOW THIS
AFTERNOON AND ESPECIALLY THIS EVENING AS WINDS CONTINUE TO
INCREASE. WITH WINDS REACHING 60+ MPH GUSTS IN THE WIND PRONE
AREAS...DECIDED TO UPGRADE ADVISORIES WE HAD OUT TO WARNINGS. ALL
THESE AREAS HAD CONSIDERABLE FRESH SNOW FOR YESTERDAYS STORM...SO
SNOW HAS NO CRUST. DECIDED ON A GROUND BLIZZARD WARNING FOR THE
WIND PRONE AREAS AND BLOWING SNOW ADVISORIES SURROUNDING THESE
AREAS. MOS GUIDANCE FOR RAWLINS SHOWING SUSTAINED WINDS OF 20KTS
TONIGHT INTO THURSDAY MORNING...SO THEY SHOULD EASILY SEE WIND
GUSTS TO 30-35MPH.

RIDGE AXIS MOVES OVERHEAD THURSDAY AFTERNOON...SO WE SHOULD SEE A
SLIGHT DECREASE IN WINDS AS THIS HAPPENS. NEXT WEAK FRONT LOOKS TO
MOVE IN BEHIND THE FRONT FOR THURSDAY NIGHT INTO FRIDAY. GUIDANCE
SHOWING LIGHT QPF DEVELOPING WITH THIS FRONT...SO DID GO WITH
CHANCE POPS FOR MOST AREAS INTO FRIDAY MORNING.

.LONG TERM...(FRIDAY NIGHT THROUGH TUESDAY)
ISSUED AT 400 AM MST WED FEB 3 2016

FRIDAY NIGHT...NORTHWEST FLOW ALOFT BACKS SLIGHTLY IN ADVANCE OF A
FEW APPROACHING SHORTWAVE TROUGHS ALOFT FROM WESTERN WYOMING AND
IDAHO. THOUGH THE LOW AND MID LEVELS LOOK FAIRLY DRY...THERE WILL BE
ENOUGH MID AND HIGH LEVEL MOISTURE FOR PARTLY CLOUDY SKIES.

SATURDAY...GFS AND ECMWF BOTH SHOW A PROGRESSIVE POSITIVELY
TILTED SHORTWAVE TROUGH ALOFT MOVING ACROSS NORTHERN WYOMING. GFS
IS SLIGHTLY SLOWER AND FURTHER WEST WITH THE TROUGH AS WELL AS
HIGHER FOR MOISTURE THAN THE ECMWF...THUS SHOWING A BIT MORE QPF
OVER OUR COUNTIES. WITH SO MUCH UNCERTAINTY AT THIS TIME AND SINCE
THESE SHORTWAVES ARE OFTEN RELATIVELY MOISTURE SCARCE...WILL ONLY
PAINT IN SOME SNOWS ACROSS THE NORTHERN LARAMIE RANGE WITH DRY
ELSEWHERE FOR NOW UNTIL ALL MODELS COME INTO MORE AGREEMENT. WILL
STILL BE A WINDY BLUSTERY DAY PER PROGGED GRADIENTS AND DEEP
UNIDIRECTIONAL FLOW.

SUNDAY...ANOTHER COLD AND BLUSTERY DAY ON TAP WITH STRONG NORTH
NORTHWEST FLOW ALOFT IN THE WAKE OF THE SHORTWAVE TROUGH WITH THE
FLOW ALOFT RETARDING AND LIMITING ANY WARMING POTENTIAL. BASED ON
PROJECTED LOW AND MID LEVEL GRADIENTS...A FEW OF OUR WIND PRONE
LOCATIONS MAY APPROACH OR EXCEED HIGH WIND CRITERIA.

MONDAY...SLOW WARMING TREND ON TAP AS HEIGHTS AND THICKNESSES ALOFT
GRADUALLY RISE WITH THE WARMING OFFSET BY NORTH NORTHWEST FLOW ALOFT
WHICH LIMITS OUR WARMING POTENTIAL. CONTINUED WINDY PER PROGGED LOW
AND MID LEVEL GRADIENTS AND DEEP UNIDIRECTIONAL FLOW.

TUESDAY...WARMING TREND CONTINUES AS HEIGHTS AND THICKNESSES
CONTINUE TO INCREASE AND WITH A DECREASE IN CLOUD COVER...ALONG
WITH SURFACE WINDS BECOMING MORE FROM THE WEST RATHER THAN
NORTHWEST.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH THURSDAY MORNING)

GENERALLY VFR CONDITIONS ARE EXPECTED TODAY AND INTO THIS EVENING.
THERE IS A CHANCE OF SOME BLOWING SNOW AND NEAR IFR VISIBILITY
ACROSS KRWL...AND KCYS LATE THIS AFTERNOON...BUT CONFIDENCE IS LOW
ON THE SPECIFIC TIMING. WINDS WILL INCREASE THIS AFTERNOON AND
TONIGHT WITH WINDS GUSTING TO NEAR 35 KNOTS AT KRWL AND POSSIBLY
KCYS LATE TONIGHT WITH SOME BLOWING SNOW.

&&

.FIRE WEATHER...
ISSUED AT 400 AM MST WED FEB 3 2016

WIDESPREAD SNOW PACK AND COLD TEMPERATURES WILL KEEP FIRE WEATHER
CONDITIONS IN CHECK OVER THE UPCOMING WEEK. STRONG WINDS RETURNING
TO SOUTHEAST WYOMING TONIGHT WITH WIND PRONE AREAS LIKELY SEEING
WIND GUSTS IN EXCESS OF 60 MPH. WINDS WILL BE GUSTING CLOSE TO 40
MPH FOR AREAS ALONG AND WEST OF THE LARAMIE RANGE AS WELL.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...BLIZZARD WARNING FROM 7 PM THIS EVENING TO 11 AM MST THURSDAY
     FOR WYZ106-110-116-117.

     WINTER WEATHER ADVISORY FROM 7 PM THIS EVENING TO 11 AM MST
     THURSDAY FOR WYZ101-103>105-107-109-113-115-118.

NE...NONE.
&&

$$

SHORT TERM...GCC
LONG TERM...RUBIN
AVIATION...TJT
FIRE WEATHER...GCC


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