Area Forecast Discussion
Issued by NWS Cheyenne, WY

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000
FXUS65 KCYS 050543
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
1043 PM MST THU FEB 4 2016

.SHORT TERM...(TONIGHT-SATURDAY NIGHT)
ISSUED AT 209 PM MST THU FEB 4 2016

THE MAIN CONCERN IN THE NEAR TERM IS HAZARDOUS TRAVEL ALONG AND WEST
OF THE LARAMIE RANGE THROUGH THIS EVENING. SNOW SHOWERS HAVE STARTED
TO DEVELOP OVER CARBON AND CONVERSE COUNTIES IN RESPONSE TO A STRONG
MID-LEVEL SHORTWAVE MOVING QUICKLY ACROSS CENTRAL WYO. THIS ACTIVITY
WILL SPREAD ACROSS THE REMAINDER OF THE CWA OVERNIGHT WITH ONLY VERY
LIGHT ACCUMULATIONS EXPECTED. WEAKENING LOW-LEVEL GRADIENTS CONTINUE
TO PROMOTE DIMINISHING WIND SPEEDS...BUT A FEW HIGHWAY SENSORS STILL
SHOW GUSTS IN THE 40-50 MPH RANGE IN THE WIND PRONE AREAS. POOR ROAD
CONDITIONS ARE OCCURRING WHERE SNOW IS FALLING AND WINDS REMAIN HIGH
ATTM...BUT IT IS NOT WIDESPREAD ENOUGH FOR AN ADVISORY. IN THE SNOWY
AND SIERRA MADRE RANGES...4 TO 7 INCHES OF SNOW WILL FALL TONIGHT.

DRY CONDITIONS WILL PREVAIL ON FRIDAY BENEATH A SHORTWAVE RIDGE. MAY
SEE SOME LINGERING SNOW SHOWERS IN THE MOUNTAINS...BUT DO NOT EXPECT
THIS TO CAUSE ANY PROBLEMS. INCREASING 700 MILLIBAR TEMPERATURES AND
SUBSIDENCE ALOFT SHOULD SUPPORT HIGH TEMPERATURES AT/ABOVE 32 F OVER
THE EASTERN PLAINS...SO TRENDED SLIGHTLY WARMER. THE NEXT POTENT MID
LEVEL DISTURBANCE WILL SWEEP ACROSS MONTANA ON FRIDAY NIGHT AND INTO
NORTHEASTERN WYOMING ON SATURDAY. THE H85 CAG-CPR GRADIENT INCREASES
TO NEAR 80 METERS BY 12Z SAT ALONG WITH 60+ KT H75 FLOW...SO ANOTHER
ROUND OF HIGH WINDS APPEARS LIKELY FOR ARLINGTON. BORDEAUX WILL HAVE
NO PROBLEM HITTING EITHER WITH AN ARL-BRX MSLP GRADIENT ON THE ORDER
OF 4-5 MILLIBARS. OUR LOCAL PROBABILISTIC MODEL IS SHOWING 80-90 PCT
PROBABILITIES OF EXCEEDING HIGH WIND CRITERIA BETWEEN 12-18Z. ISSUED
A HIGH WIND WATCH FOR THE WIND PRONE AREAS FROM FRI EVE THROUGH MUCH
OF SAT. BLOWING SNOW IS POSSIBLE...BUT WARMING TEMPERATURES/CRUSTING
OF SNOW SHOULD KEEP IMPACTS MINIMAL.

WE WILL ALSO NEED TO WATCH SOME OF OUR LOWER ELEVATIONS FOR GUSTS IN
THE NEIGHBORHOOD OF 60 MPH ON SATURDAY AFTERNOON/EVENING. THE GFS IS
SHOWING 65-75 KTS IN THE H7-H75 LAYER OVER BOTH CHEYENNE AND LARAMIE
AT 00Z SUN...AND NAM/GFS BUFKIT SOUNDINGS SHOW STEEP LAPSE RATES AND
EXCELLENT MIXING POTENTIAL. THE MAIN LIMITING FACTOR APPEARS TO BE A
LACK OF STRONGER DOWNWARD OMEGA AT 725 MILLIBARS...BUT THE THREAT IS
DEFINITELY THERE. MAV GUIDANCE SHOWS SUSTAINED WINDS AROUND 28 TO 32
KTS. THERE WILL MOST LIKELY BE A SOME SNOW SHOWERS OVER OUR NORTHERN
ZONES ON SATURDAY NIGHT ASSOCIATED WITH THE AFOREMENTIONED WAVE. NOT
EXPECTING MUCH FOR IMPACTS WITH THE FAST-MOVING SYSTEM.

.LONG TERM...(SUNDAY THROUGH THURSDAY)
ISSUED AT 235 PM MST THU FEB 4 2016

MEDIUM TO LONG RANGE MODELS INDICATE GENERALLY QUIET WEATHER LATE
THIS WEEKEND AND THROUGH MOST OF NEXT WEEK. WITH THE EXCEPTION OF
STRONG WINDS...PRECIP CHANCES WILL BE LOW WITH LIMITED IMPACTS.
THERE IS HIGH CONFIDENCE IN A GRADUAL WARMING TREND THROUGH THE
MIDDLE OF NEXT WEEK WITH TEMPERATURES ABOVE NORMAL AS EARLY AS
TUESDAY. HIGH TEMPERATURES MAY CLIMB TOWARDS THE MID TO UPPER 50S
ON WEDNESDAY ACROSS THE LOWER ELEVATIONS...BUT THIS WILL LIKELY
DEPEND ON ANY REMAINING SNOWPACK.

FORECAST GUIDANCE IN GOOD AGREEMENT...SHOWING NORTHERLY FLOW ALOFT
CONTINUING THROUGH TUESDAY AS THE PACIFIC UPPER LEVEL RIDGE AXIS
NUDGES EASTWARD AND FLATTENS A BIT AS IT MOVES INTO THE ROCKY
MOUNTAIN REGION BY WEDNESDAY. NO REAL CONCERNS WITH PRECIPITATION
CHANCES AS THE BACK DOOR COLD FRONT MODELS WERE SHOWING YESTERDAY
IS A LITTLE FURTHER EAST TODAY. SUNDAY WILL BE COLD AS THE PACIFIC
STORM SYSTEM AND ASSOCIATED COLD FRONT FROM SATURDAY RAPIDLY
MOVES EAST OF THE FORECAST AREA BY SUNDAY. HIGH TEMPERATURES IN
THE 20S TO MID 30S ARE EXPECTED...WARMEST ACROSS WESTERN NEBRASKA.
A PROLONGED PERIOD OF VERY WINDY CONDITIONS ARE EXPECTED SUNDAY
THROUGH TUESDAY ACROSS PORTIONS OF THE FAR EASTERN WYOMING PLAINS
AND WESTERN NEBRASKA DUE TO A STRONG PRESSURE GRADIENT ACROSS THE
AREA. NORTHWEST WINDS MAY GUST BETWEEN 45 TO 55 MPH AT TIMES ALONG
AND EAST OF THE LARAMIE RANGE TOWARDS THE SOUTHERN NEBRASKA
PANHANDLE.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY EVENING)
ISSUED AT 1035 PM MST THU FEB 4 2016

SCATTERED LIGHT SNOW SHOWERS WILL END FROM WEST TO EAST THROUGH
08Z. THERE WILL BE BRIEF MVFR-IFR VIS WITH THE SHOWERS. OTHERWISE...
VFR CIGS WILL CONTINUE OVERNIGHT WITH PARTIAL CLEARING FRIDAY.
GUSTY WEST TO NORTHWEST WINDS WILL PRODUCE BLOWING SNOW ACROSS
PORTIONS OF SOUTHEAST WY...MAINLY AFFECTING AREAS WEST OF LARAMIE
TO RAWLINS OVERNIGHT. BREEZY WEST TO NORTHWEST WINDS WILL PREVAIL
FRIDAY.

&&

.FIRE WEATHER...
ISSUED AT 209 PM MST THU FEB 4 2016

MINIMAL FIRE WEATHER CONCERNS WITH A WIDESPREAD SNOW PACK ACROSS
THE ENTIRE FIRE DISTRICT. STRONG WINDS WILL RETURN TO MUCH OF THE
AREA BY THE WEEKEND...ESPECIALLY OVER THE WIND PRONE AREAS. THESE
WINDS MAY WARM US UP SOME...BUT NOT TOO MUCH AS COLD AIR REMAINS
OVERHEAD.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...HIGH WIND WATCH FROM FRIDAY AFTERNOON THROUGH SATURDAY AFTERNOON
     FOR WYZ106-110-116-117.

NE...NONE.
&&

$$

SHORT TERM...CLH
LONG TERM...TJT
AVIATION...MAJ
FIRE WEATHER...GCC/CLH


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