Area Forecast Discussion
Issued by NWS Cheyenne, WY

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FXUS65 KCYS 272254
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
354 PM MST FRI FEB 27 2015

.SHORT TERM...(THIS EVENING THROUGH SUNDAY NIGHT)
ISSUED AT 353 PM MST FRI FEB 27 2015

CLOUDS HAVE HUNG ON ACROSS EXTREME SE WY INTO MUCH OF THE
PANHANDLE THIS AFTERNOON WITH A FEW FLURRIES NOTED AS WELL.
EXPECT GENERALLY QUIET WEATHER ACROSS THE CWA OVERNIGHT THROUGH
MUCH OF SATURDAY BUT CHILLY TEMPERATURES WILL PERSIST. A FEW
FLURRIES STILL POSSIBLE MAINLY NEAR THE COLORADO BORDER THIS
EVENING DUE TO THE UPSLOPE PATTERN INDUCED BY THE CHEYENNE RIDGE.

EXPECT TO SEE LIGHT SNOW INCREASE FROM THE SW AGAIN LATE SATURDAY
AS AN IMPULSE RIDES ENE FROM AN UPPER LOW ALONG THE CALIFORNIA
COAST AND SFC UPSLOPE STEPS UP A BIT IN RESPONSE TO AN INCREASING
SFC PRESSURE GRADIENT MAINLY ACROSS SRN WY. BETTER UPPER DYNAMICS
APPEAR THEY WILL REMAIN SOUTH OF THE CWA SO PATTERN SIMILAR TO
LAST NIGHT WHERE SNOW WILL LIKELY BE LIGHT IN NATURE WITH GROWTH
RATES NOT ALL THAT IMPRESSIVE. A GENERAL 1-3 INCHES LOOKS A DECENT
BET ACROSS THE SRN PART OF THE CWA SAT NIGHT INTO SUNDAY MORNING
BEFORE ENDING. TEMPERATURES WILL REMAIN COLD THROUGH THE WEEKEND
AS THE SFC HIGH SETTLES DOWN THE HIGH PLAINS. MAINLY DRY SUNDAY
AFTERNOON AND NIGHT AS SHORT RIDGING NOSES ACROSS THE AREA FROM
COLORADO.

.LONG TERM...(MONDAY THROUGH FRIDAY)
ISSUED AT 353 PM MST FRI FEB 27 2015

AN ENERGETIC PATTERN SHAPING UP EARLY NEXT WEEK AS A SERIES OF
SHORTWAVES RIDE THE NOSE OF THE POLAR JET INTO THE INTERMOUNTAIN
WEST. OUTSIDE OF THE MOUNTAINS...MONDAY ACTUALLY LOOKS TO BE DRY
AND LIKELY ABOVE FREEZING IN LOWER ELEVATIONS. THE SNOWY/SIERRA
MADRE RANGES WILL BEGIN TO SEE SNOW DURING THE DAY ON MONDAY AS
THE PREVIOUSLY CUT-OFF GREAT BASIN UPPER LOW PHASES WITH THE NRN
STREAM. MOIST OROGRAPHIC FLOW WILL ENSUE AHEAD OF THIS FTR
RESULTING IN THE MOUNTAINS SNOWS. SEVERAL INCHES WILL POSSIBLE IN
THE HIER TERRAIN BY SUNSET MONDAY. 12Z MODELS PROG THE MOISTURE
TO HOLD OFF ACROSS THE PLAINS/VALLEYS UNTIL THE AFOREMENTIONED
SHORTWAVE TROUGH RIDES ATOP A SOUTH-MOVING COLD FRONT MONDAY NT.
THE INITIAL SHORTWAVE TROF SLIDES EAST FOR TUESDAY WITH A
SECONDARY SHORTWAVE MOVING INTO THE REGION PROLONGING SNOW
ACCUMULATIONS ACROSS THE AREA. THE POTENTIAL EXISTS FOR SOME
SIGNIFICANT ACCUMULATIONS LATE MONDAY INTO TUESDAY ESPECIALLY OVR
THE HIER TERRAIN. THE OTHER PART OF THIS EVENT THAT WILL HAVE
IMPACTS WILL BE THE VERY COLD TEMPERATURES THAT WILL LAST TUESDAY
AND WEDNESDAY AS 1040MB SETTLES RIGHT OVER THE AREA. MODELS PROG
-25C AT H7 IN THE CORE OF THE ARCTIC AIR MASS. THE RESULT WILL BE
FOR HIGH TEMPERATURES THAT WILL ONLY REACH THE TEENS TUE-WED WITH
LOWS TUESDAY NIGHT LIKELY NEGATIVE SINGLE DIGITS BELOW ZERO...AND
EVEN THAT IS PROBABLY BEING OPTIMISTIC. FORTUNATELY THE SNOW WILL
COME TO AN END BY LATE TUESDAY. DRY CONDITIONS AND MODERATING
TEMPERATURES RETURN THU-FRI AS FLOW FLATTENS WHILE THE PATTERN
DE-AMPLIFIES. IN FACT...EXPECT HIGH TEMPERATURES TO RETURN INTO
THE 40S BY FRIDAY. BREEZY CONDITIONS WILL ACCOMPANY THESE WARMER
TEMPERATURES ACROSS SE WYOMING THU-FRI.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1106 AM MST FRI FEB 27 2015

A CHALLENGING AVIATION PERIOD SHAPING UP WITH ONGOING IFR
CIGS/VSBYS AT KCYS AND KSNY LIKELY IMPROVING BACK TO MVFR BY
19-21Z. OTHERWISE SHOULD SEE GENERALLY VFR CONDITIONS ELSEWHERE.
THE ONE TRICKY SPOT WILL BE AT KBFF WHERE CIGS WILL LIKELY BOUNCE
MVFR/VFR THRU THE AFTERNOON. WILL SEE MVFR CIGS RETURN TO
KCYS AND WRN NEBRASKA TERMINALS 00-03Z AS SOUTH/SOUTHEAST WINDS
PERSIST. WINDS WILL TURN TO WESTERLY AT KCYS BY AROUND 08Z WHICH
SHOULD ERODE LOWER CLOUDS BACK TO A VFR BKN060 LAYER. COLD FRONT
WILL BEGIN TO PUSH FROM NORTH TO SOUTH 15-18Z SATURDAY...WHICH
WILL LEAD TO ONCE AGAIN DETERIORATING CONDITIONS AND -SN CHANCES
RETURNING JUST BEYOND THE PERIOD SATURDAY AFTERNOON AND EVENING.

&&

.FIRE WEATHER...
ISSUED AT 353 PM MST FRI FEB 27 2015

NO CONCERNS ANTICIPATED INTO EARLY NEXT WEEK WITH COOL TO COLD
TEMPERATURES AND PERIODS OF SNOW KEEPING CONDITIONS NON-CRITICAL.

&&

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

&&

$$

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



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