Area Forecast Discussion
Issued by NWS Cheyenne, WY

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000
FXUS65 KCYS 291000
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
400 AM MDT FRI APR 29 2016

.SHORT TERM...(TODAY THROUGH SUNDAY AFTERNOON)
ISSUED AT 400 AM MDT FRI APR 29 2016

WINTER STORM WARNINGS AND WINTER WEATHER ADVISORIES ARE IN EFFECT
FOR TODAY AND TONIGHT. ALTHOUGH THERE ARE ADVISORIES AND WARNINGS
IN EFFECT...THERE ARE SEVERAL FORECAST CONCERNS AND CHALLENGES.
MODELS CONTINUE TO VARY FROM RUN TO RUN. THE LATEST SOLUTIONS ARE
A BIT FARTHER EAST WITH THE MAIN AREA OF PRECIPITATION. THIS WILL
AFFECT SNOW AMOUNTS ACROSS WESTERN PORTIONS OF THE FORECAST AREA
WITH MANY PLACES WEST OF THE LARAMIE RANGE NOW EXPECTED TO REMAIN
BELOW ADVISORY LEVELS AT LOWER ELEVATIONS AND BELOW WARNING LEVELS
IN THE MOUNTAINS. FOR NOW KEPT THESE HEADLINES GOING TO AVOID
CONFUSION AND TO AVOID FLIP FLOPPING SHOULD THE LOW TAKE A FARTHER
WEST TRACK...ALTHOUGH THAT IS LOOKING UNLIKELY.

ONE BIG CONCERN REGARDING MODEL QPF OUTPUT IS THAT THUNDERSTORMS
ARE CURRENTLY DEVELOPING ACROSS MUCH OF OKLAHOMA AND THE TEXAS
PANHANDLE. THESE VERY LIKELY WILL INHIBIT MUCH OF THE LOW LEVEL
MOISTURE FROM ACTUALLY REACHING SE WY AND WRN NE PANHANDLE...WHICH
MEANS THE MODELS ARE PROBABLY TO HIGH ON QPF AMOUNTS OVER THE
FORECAST AREA. ALSO THE MID TO UPPER LEVEL FLOW IS FROM THE
SOUTHWEST ACROSS THE SOUTHERN PLAINS...SUCH THAT MOISTURE
ASSOCIATED WITH THUNDERSTORM ACTIVITY WILL BE LOFTED OFF TO THE
NORTHEAST...WITH NO CHANCE FOR MOISTURE TO BE WRAPPED BACK INTO
THE FORECAST AREA. AT ANY RATE...THE CURRENT FORECAST MAY BE
OVERDONE ON QPF AND THEREFORE SNOWFALL AMOUNTS FOR MOST OF THE
FORECAST AREA. CERTAINLY WILL KEEP A CLOSE EYE ON RADAR AND
SATELLITE TRENDS THE NEXT SEVERAL HOURS AS WELL AS MODEL TRENDS.

NOT 100 PERCENT CONFIDENT ON THE OVERALL IMPACTS WITH THIS WEATHER
SYSTEM. A LOT OF THE DAYTIME IMPACTS WILL DEPEND ON SNOWFALL
RATES. WHERE SNOW RATES AREA HEAVIER...ROADS MAY BECOME SLUSHY TO
SLIPPERY...BUT ELSEWHERE MUCH OF THE SNOW WILL MELT ON CONTACT
WITH ROAD SURFACES...SUCH THAT OVERALL TRAVEL IMPACTS MAY BE
LIMITED. SOME OF THE WORST ROAD CONDITIONS SHOULD BE FRIDAY NIGHT
AS LIGHT SNOW FALLS ACROSS MUCH OF THE AREA AND AIR TEMPERATURES
DIP TO AROUND FREEZING AT HIGHER ELEVATIONS. VALLEY AREAS...LIKELY
THE LOWER NORTH PLATTE RIVER VALLEY MAY NEVER DROP BELOW FREEZING
SUCH THAT ROADS AREA ONLY WET. THE MAIN IMPACTS THE NEXT 36 HOURS
WILL BE VERY DEPENDENT ON SNOW RATES AND ACTUAL SURFACE
TEMPERATURES. WHILE 6 TO 10 INCHES OF SNOW IS EXPECTED ACROSS THE
CHEYENNE RIDGE AND POSSIBLY INTO THE PINE RIDGE...MUCH OF THE SNOW
WILL QUICKLY MELT...POSING LESS IMPACT THEN OTHERWISE WOULD OCCUR
EARLIER IN THE SPRING.

.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 400 AM MDT FRI APR 29 2016

A GENERALLY DRIER AND WARMER WEATHER REGIME SHOULD FINALLY SET UP
OVER THE CWA THIS PERIOD. A WEAKENING UPPER LOW NEAR THE 4 CORNERS
AREA SUNDAY EVENING IS FORECAST TO OPEN AND SHEAR EAST ACROSS THE
SOUTHERN ROCKY MTNS INTO THE SOUTHERN PLAINS SUNDAY NIGHT AND
MONDAY WITH JUST A GLANCING SHOT OF LIGHT PCPN POSSIBLE OVER THE
FAR SOUTHERN CWA. BY MIDWEEK A LARGE AMPLITUDE UPPER RIDGE SETS UP
OVER THE ROCKY MTN CHAIN PROVIDING DRY CONDITIONS WITH TEMPS
WARMING TO ABOVE SEASON AVERAGES BY THURSDAY. THERE WILL BE ONE
SHORTWAVE WHICH MAY BE SOME NUISANCE LATER MONDAY INTO TUESDAY.
GFS VERY WEAK WITH THIS FEATURE BUT LATEST EC CLOSES OFF A SMALL
UPPER LOW OVER THE WESTERN DAKOTAS MONDAY AND MOVES IT SOUTHWEST
ACROSS WYOMING MONDAY NIGHT AND THEN SLOWLY ACROSS COLORADO
TUESDAY AND WEDS. SEEMS LATELY THIS AREA CANNOT AVOID THESE UPPER
LOWS BUT WILL SEE IF THIS SOLUTION REMAINS CONSISTENT...WHICH
WOULD NECESSITATE SOME POPS AND COOLER TEMPS FOR TUESDAY AND WEDS.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY EVENING)
ISSUED AT 1122 PM MDT THU APR 28 2016

MVFR/IFR CIGS FOR MOST TERMINALS OVERNIGHT.  EXPECT CONDITIONS TO
LOWER TO WIDESPREAD IFR/LIFR CONDITIONS AREAWIDE FRIDAY MORNING WITH
RAIN AND SNOW SPREADING OVER THE AREA.


&&

.FIRE WEATHER...
ISSUED AT 323 AM MDT FRI APR 29 2016

A WINTER LIKE STORM SYSTEM WILL MOVE ACROSS THE AREA TODAY AND SATURDAY
PRODUCING WIDESPREAD RAIN AND SNOW. TEMPERATURES WILL BE WELL BELOW
NORMAL WITH NO CRITICAL FIRE WEATHER CONCERNS THE NEXT SEVERAL
DAYS.


&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...WINTER STORM WARNING UNTIL 6 PM MDT SATURDAY FOR WYZ114-116>119.

     WINTER WEATHER ADVISORY FROM NOON TODAY TO 6 PM MDT SATURDAY FOR
     WYZ106>108.

     WINTER WEATHER ADVISORY UNTIL 6 PM MDT THIS EVENING FOR WYZ112.

     WINTER WEATHER ADVISORY UNTIL 6 AM MDT SATURDAY FOR WYZ110-115.

NE...WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO 6 PM MDT
     SATURDAY FOR NEZ002-003-095-096.

     WINTER STORM WARNING UNTIL 6 PM MDT SATURDAY FOR NEZ020-054-055.

     WINTER WEATHER ADVISORY FROM NOON TODAY TO 6 PM MDT SATURDAY FOR
     NEZ019-021.

&&

$$

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



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