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000
FXUS65 KCYS 010500
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
1000 PM MST SAT FEB 28 2015

.UPDATE...
ISSUED AT 952 PM MST SAT FEB 28 2015

LOOKING AT RADAR MOSAIC...SNOW IS REALLY HAVING A TOUGH TIME
GETTING OVER THE SOUTH LARAMIE RANGE THIS EVENING. GETTING SOME
SNOW WEST OF THE LARAMIE RANGE...BUT NOTHING SO FAR TO THE EAST.
WENT AHEAD AND LOWERED POPS SOME FOR THE OVERNIGHT HOURS. UPDATES
HAVE BEEN SENT.

&&

.SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT)
ISSUED AT 340 PM MST SAT FEB 28 2015

A FEW SNOW FLURRIES WILL LINGER ALONG THE EASTERN FRINGES OF THE
SOUTHERN LARAMIE RANGE THROUGH THIS AFTERNOON. THE MAIN CHANCES
FOR ACCUMULATING SNOW WILL OCCUR THIS EVENING AND INTO THE
OVERNIGHT AS SUBTLE SHORTWAVE FEATURES MOVE INTO SOUTHEAST WYOMING
FROM COLORADO...AND ELEVATED WARM ADVECTION DEVELOPS. THE BEST
CHANCES FOR SNOW ACCUMULATIONS OUTSIDE OF THE MOUNTAINS WILL BE
ALONG AND NEAR THE COLORADO BORDER BUT EVEN THERE ANY
ACCUMULATIONS WILL BE MINIMAL AND GENERALLY LESS THAN ONE INCH.
KEPT SLIGHT CHANCES GOING INTO EAST CENTRAL WYOMING AND THE
NORTHERN NEBRASKA PANHANDLE...BUT IT IS LOOKING LESS LIKELY THAT
ANY SNOW WILL OCCUR IN THOSE AREAS TONIGHT OR TOMORROW WITH THE
BEST UPPER LEVEL FORCING WELL TO THE SOUTH.

WILL HAVE TO KEEP AN EYE ON HOW THE UPPER LEVELS EVOLVE EARLY NEXT
WEEK. MODELS SHOWING A CUT OFF LOW EJECTING NORTHEASTWARD OUT OF
CALIFORNIA AS A KICKER DROPS SOUTH OFF THE PACIFIC NORTHWEST
COAST. ECMWF INITIALLY KEEPS MUCH OF THE ENERGY OVER SOUTHCENTRAL
WYOMING MONDAY INTO MONDAY NIGHT AND THEN QUICKLY PUSHES THINGS
EASTWARD. THE GFS BRINGS THE MAIN ENERGY OVER FAR SOUTHEAST
WYOMING AND PRODUCES HIGHER AMOUNTS OF PRECIPITATION THERE. NOT
CONFIDENT IN EITHER SOLUTION AND SOMEWHAT SURPRISED HOW MUCH
PRECIPITATION THE MODELS ARE PRODUCING GIVEN THE PLACEMENT OF THE
UPPER LEVEL JET.

DEPENDING ON THE NEXT ROUND OF MODEL RUNS...MAY NEED WINTER WEATHER
HEADLINES FOR SOUTHCENTRAL WYOMING MONDAY THROUGH MONDAY NIGHT.
LIGHT SNOW COULD START FALLING IN THAT AREA LATE SUNDAY NIGHT BUT
AT THIS TIME IT APPEARS A MAJORITY OF THE SNOW WILL FALL AFTER 12Z
MONDAY THROUGH MONDAY NIGHT ACROSS THIS AREA.

.LONG TERM...(TUESDAY THROUGH SATURDAY)
ISSUED AT 315 PM MST SAT FEB 28 2015

MAIN FORECAST CONCERN IN THE MEDIUM RANGE WILL BE THE CONTINUING
WINTER WEATHER EVENT ON TUESDAY. MODELS ARE IN PRETTY GOOD
AGREEMENT WITH THIS STORM SYSTEM...SHOWING A SECONDARY SHORTWAVE
ALOFT DIGGING SOUTHWARD...WHICH WILL BE ASSOCIATED WITH THE
ARCTIC AIRMASS MOVING INTO WYOMING EARLY TUESDAY MORNING. HIGH
TEMPERATURES ON TUESDAY WILL LIKELY BE SIMILAR TO THE LOW
TEMPERATURES MONDAY NIGHT...AND GENERALLY IN THE TEENS TO LOW 20S.
TEMPERATURES WILL LOWER INTO THE SINGLE DIGITS AND LOW TEENS
THROUGH THE AFTERNOON AS THE 1035MB ARCTIC HIGH AT THE SURFACE
MOVES INTO THE AREA. KEPT A 60 PCT TO 80 PCT CHANCE OF SNOW FOR
MOST OF SOUTHEAST WYOMING INTO TUESDAY EVENING FOR AN ADDITIONAL 1
TO 3 INCHES OF SNOW ACCUMULATION. LOW TEMPERATURES TUESDAY NIGHT
WILL BE TRICKY AND WILL GREATLY DEPEND ON THE EXTENT OF SURFACE
SNOW COVER...DEPTH...AND IF SKIES CLEAR OUT OR NOT. CONSIDERING HOW
PROGRESSIVE THE SYSTEM IS AS INDICATED BY MODELS...BELIEVE MOST OF
THE FORECAST AREA AND ESPECIALLY NORTH OF I80...WILL HAVE CLEARING
SKIES OVERNIGHT. LOW TEMPERATURES MAY APPROACH -15 TO -20 IN THE
MORE SHELTERED VALLEYS ACROSS SOUTHEAST WYOMING WITH THE CENTER OF
THE ARCTIC HIGH JUST EAST OF THE LARAMIE RANGE.
ELSEWHERE...TEMPERATURES BETWEEN -5 TO -10 APPEAR LIKELY AT THIS
TIME IF BROKEN TO OVERCAST CONDITIONS CONTINUE THROUGH MOST OF THE
NIGHT.

WEDNESDAY THROUGH THE END OF THE WEEK...SOME FLURRIES ARE POSSIBLE
AS THE STORM SYSTEM EXITS THE REGION TO OUR SOUTH. WEDNESDAY WILL
BE THE COLDEST DAY OF THE WEEK WITH HIGHS STRUGGLING TO REACH THE
LOW TO MID TEENS. KEPT HIGHS A FEW DEGREES ABOVE MOS...BUT GAMBLING
THAT THE WESTERLY WINDS AND MARCH SUNSHINE WILL RESULT IN
TEMPERATURES A FEW DEGREES HIGHER THAN GUIDANCE.
OTHERWISE...TEMPERATURES MAY BE STUCK IN THE SINGLE DIGITS THROUGH
THE AFTERNOON. EITHER WAY...A WARMING TREND IS EXPECTED FOR THE
REMAINDER OF THE WEEK AS THE STRONG EASTERN PACIFIC RIDGE EXPANDS
EASTWARD A BIT INTO THE CENTRAL AND SOUTHERN ROCKY MOUNTAINS. DUE
TO POTENTIAL SNOW COVER...DID KEEP TEMPERATURES LOWER THAN MOS
THROUGH THE WEEK...WITH TEMPERATURES ABOVE GUIDANCE BY NEXT
WEEKEND AS MOST OF THE SNOW SHOULD MELT BY THAT TIME. EXPECT HIGHS
TO RETURN TO THE 40S TO AROUND 50 BY FRIDAY AND SATURDAY
AFTERNOON.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 952 PM MST SAT FEB 28 2015

TOUGH FORECAST FOR OUR SOUTHEAST WYOMING AIRPORTS. RADAR SHOWING
AREA OF SNOW FILLING IN FROM KCYS TO KLAR...BUT IT IS NOT TOO
HEAVY AND BARELY RESTRICTING VISIBILITIES. GOING TO HOLD OFF
ONLOWERING CONDITIONS UNTIL AFTER 12Z AND CONFINE LOWER CONDITIONS
TO KLAR.

&&

.FIRE WEATHER...

ISSUED AT 240 AM MST SAT FEB 28 2015

C0LDER THAN NORMAL TEMPERATURES...AMPLE SURFACE MOISTURE FROM
SNOWFALL...AND HIGH RELATIVE HUMIDITIES WILL PRECLUDE FIRE WEATHER
CONCERNS THROUGH NEXT WEEK.

&&

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

$$

UPDATE...GCC
SHORT TERM...SML
LONG TERM...TJT
AVIATION...GCC
FIRE WEATHER...MAJ