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000
FXUS65 KCYS 141740
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
1140 AM MDT MON APR 14 2014

.UPDATE...
ISSUED AT 1123 AM MDT MON APR 14 2014

ALWAYS AN INTERESTING CHALLENGE...FORECASTING ACROSS OUR
COUNTIES...ESPECIALLY TODAY...THE DAY AFTER A WIDESPREAD SNOWFALL
EVENT WITH FULL SUNSHINE AND DOWNSLOPE WARMING KATABATIC WINDS.

PRIMARY CHALLENGES THIS AFTERNOON ARE TEMPERATURES AND WINDS.

TEMPERATURES...11 AM TEMPERATURES AT LOWER ELEVATIONS RANGE FROM
THE MIDDLE TEENS AT LARAMIE IN THE LARAMIE VALLEY...TO THE MID TO
UPPER 30S AT CHADRON...SCOTTSBLUFF AND ALLIANCE. INHERITED
FORECAST MAXIMUM TEMPERATURES FROM OUR MIDNIGHT SHIFT SHORT TERM
FORECASTER LOOK ON TRACK...CONSIDERING THE HIGH SNOW ALBEDO AND
REFLECTIVITY...COUNTERACTING THE ABUNDANT SUNSHINE AND DOWNSLOPE
WARMING. MINOR ADJUSTMENTS MADE...AND HAVE LOADED THE LAMP
GUIDANCE MAX TEMPERATURES HOURLY THROUGH THIS AFTERNOON...BASED ON
EXPERIENCE...DOWNSLOPE KATABATIC WARMING...THOUGH ALWAYS TRICKY
ACROSS THE LARGE PROTECTED LARAMIE VALLEY WITH SNOWPACK AND
LIMITED LOW LEVEL MIXING...ALSO KNOWN AS WINDS.

WINDS...ALSO LOADED THE LAMP HOURLY WINDS THROUGH THIS AFTERNOON...
AS THESE LAMP WINDS TEND TO PREDICT QUITE WELL OUR WINDS SINCE
THE LAMP WINDS ARE UPDATED HOURLY...IN CONTRAST TO THE LESSER
UPDATED MET MOS AND GFS MOS WINDS. THANK YOU TO OUR OFFICE AVIATION
AND FIRE WEATHER PROGRAM LEADER FOR PASSING ON THIS USEFUL
INFORMATION.

&&

.SHORT TERM...(TODAY THROUGH WEDNESDAY NIGHT)
ISSUED AT 400 AM MDT MON APR 14 2014

WHAT A DIFFERENCE A DAY MAKES. THE SNOW AND COLD WILL SOON BE A
DISTANT MEMORY AS DOWNSLOPE WEST WIND BEGINS THE WARMING PROCESS
WITH SNOW QUICKLY MELTING ACROSS THE AREA UNDER A MOSTLY SUNNY SKY
TODAY. TEMPERATURES WILL STRUGGLE TO WARM SOMEWHAT WHERE THE FRESH
SNOW IS DEEPEST...BUT WITH THE MID APRIL SUN ANGLE MOST SNOW
SHOULD BE GONE BY DAYS END. ANY SNOW THAT IS LEFT OUTSIDE OF THE
MOUNTAINS WITH QUICKLY MELT WEDNESDAY AS GUSTY WEST WINDS KICK IN
AND TEMPERATURES RISE INTO THE 50S AND 60S.

VIRTUALLY NO CHANCE FOR PRECIPITATION TODAY OR TUESDAY BUT ANOTHER
BLAST OF COLD AIR WILL MAKE ITS WAY ACROSS THE AREA WEDNESDAY
ALONG WITH SOME SNOW. A COLD FRONT WILL MOVE THROUGH TUESDAY NIGHT
WITH COLD AIR ADVECTION CONTINUING THROUGH WEDNESDAY AFTERNOON.
MAIN THREAT FOR SNOW APPEARS TO BE OVER SOUTHEAST WYOMING BUT
AMOUNTS ARE GENERALLY EXPECTED TO BE MINIMAL. MOST SNOW
ACCUMULATION SHOULD BE CONFINED TO THE MOUNTAINS WITH MUCH OF THE `
SNOW MELTING AS IT REACHES THE GROUND ELSEWHERE. TRAVEL IMPACTS
SHOULD BE MINIMAL WITH WEDNESDAYS SYSTEM.

.LONG TERM...(THURSDAY THROUGH SUNDAY)
ISSUED AT 330 AM MDT MON APR 14 2014

COOL SFC AIRMASS WILL HOLD AGAINST THE MTNS THURSDAY WITH SOME
RAIN AND SNOW POSSIBLE MAINLY OVER THE PLAINS AS THE UPPER TROUGH
PASSES TO THE EAST OF THE CWA. AFTER THAT A MILD AND MAINLY DRY
PATTERN EXPECTED TO SET UP OVER THE REGION THROUGH THE WEEKEND
WITH AN UPPER RIDGE PASSING ACROSS FRIDAY LEAVING A SOMEWHAT SPLIT
FLOW PATTERN BEHIND IT. ONE UPPER SYSTEM LOOKS TO PASS SOUTH OF
THE AREA LATE SATURDAY INTO SUNDAY BUT UNSURE HOW MUCH IF ANY
EFFECT IT WILL HAVE ON AREA WEATHER. HAVE KEPT A DRY FCST IN PLACE
BUT MAY NEED TO NUDGE POPS UP SOME IF IT TREKS A BIT FARTHER
NORTHWARD.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 330 AM MDT MON APR 14 2014

SOME PATCHY MVFR CONDITIONS DUE MAINLY TO FOG EARLY THIS MORNING
WILL GIVE WAY TO VFR ACROSS THE ENTIRE AREA LATER THIS MORNING AND
CONTINUING THROUGH EARLY TUESDAY.


&&

.FIRE WEATHER...
ISSUED AT 330 AM MDT MON APR 14 2014

COOL AND DRY TODAY WITH LOTS OF SUNSHINE. TEMPERATURES WILL REBOUND
TODAY FOLLOWING ALL THE SNOW AND COLD SUNDAY. WESTERLY WINDS WILL
BE ON THE BREEZY SIDE AT 15 TO 25 MPH WITH SOME HIGHER GUSTS. WINDY
OVER SOUTHEAST WYOMING ON TUESDAY AND BREEZY IN THE PANHANDLE OF
NEBRASKA. MUCH WARMER AND CONTINUED DRY WEDNESDAY WITH HIGHS IN THE
50S WEST TO 60S EAST. ANOTHER SHOT OF UNSEASONABLY COLD AIR WEDNESDAY
WITH A CHANCE FOR SNOW...ESPECIALLY OVER SOUTHEAST WYOMING. CONTINUED
CHANCES OF SNOW ON THURSDAY...THEN DRYING OUT WITH A WARMING TREND
INTO THE WEEKEND.

&&

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

$$

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