Area Forecast Discussion
Issued by NWS Cheyenne, WY

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FXUS65 KCYS 012243
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
343 PM MST SUN MAR 1 2015

.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 343 PM MST SUN MAR 1 2015

MAIN FORECAST FOCUS IS ON SNOW CHANCES AND SNOW AMOUNTS MONDAY INTO
TUESDAY. UPGRADED THE WINTER STORM WATCH TO A WARNING FOR THE SNOWY
AND SIERRA MADRE RANGES STARTING EARLY MONDAY MORNING AND CONTINUING
THROUGH TUESDAY AFTERNOON. ALSO ISSUED A WINTER STORM WATCH FOR
NORTHERN CARBON COUNTY AND THE WESTERN FRINGES OF ALBANY COUNTY FOR
LATE MONDAY AFTERNOON THROUGH TUESDAY AFTERNOON.

BASED ON RADAR IMAGES AND SURFACE OBSERVATIONS SHOWING WIDESPREAD
PRECIPITATION OVER THE SOUTHWEST CONUS...FEEL CONFIDENT A LARGE
AMOUNT OF MID AND UPPER LEVEL MOISTURE WILL SPREAD ACROSS THE
FORECAST AREA TOMORROW INTO EARLY TUESDAY. WATER VAPOR ALSO SHOWING
THE STREAM OF PACIFIC MOISTURE LIFTING NORTHEASTWARD THROUGH BAJA
CALIFORNIA...A FAVORED TRACK FOR MOISTURE TO REACH THE CENTRAL
ROCKIES...AS THE MOISTURE BYPASSES THE BLOCKING SIERRA NEVADA
MOUNTAINS.

MAIN CONCERN IS THE ACTUALLY TRACK UPPER LEVEL ENERGY WHICH IS
CURRENTLY OVER CALIFORNIA WILL TAKE ONCE A KICKER SYSTEM DROPS SOUTH
ALONG THE PACIFIC COAST. MODELS ARE IN FAIRLY GOOD AGREEMENT
EJECTING THE UPPER LEVEL DISTURBANCE NORTHEAST INTO SOUTHCENTRAL
WYOMING MONDAY BEFORE TRACKING EAST INTO THE PLAINS MONDAY NIGHT.
SOUTHCENTRAL WYOMING IS WHEN A BULK OF THE SNOW WILL FALL ACROSS
THE AREA. FULLY EXPECTING WINTER WEATHER ADVISORIES TO BE HOISTED
EITHER TONIGHT OR EARLY TOMORROW FOR MUCH OF THE FORECAST AREA.

IN ADDITION TO THE SOUTHERN STREAM DISTURBANCE...AS STRONG ARCTIC
COLD FRONT WILL MOVE ACROSS THE AREA MONDAY NIGHT. SNOW WILL BRIEFLY
INTENSIFY AS THE FRONT MOVES ACROSS THE AREA. THE BIGGER CONCERN IS
GUSTY NORTHERLY WINDS WHICH WILL PRODUCE BLOWING AND DRIFTING
SNOW...AND WHEN COMBINED WITH FALLING SNOW WILL SIGNIFICANTLY
REDUCE VISIBILITIES ACROSS MUCH OF THE FORECAST AREA. ALSO WIND
CHILLS WILL PLUMMET LATE TUESDAY INTO TUESDAY NIGHT. MOST LIKELY
WIND CHILL ADVISORIES AND WARNING WILL BE NEEDED TUESDAY NIGHT
INTO WEDNESDAY MORNING.

.LONG TERM...(SATURDAY NIGHT THROUGH THURSDAY)
ISSUED AT 330 PM MST THU JAN 15 2015

WEATHER PATTERN TO BECOME MORE ACTIVE THIS WEEKEND AND INTO NEXT
WEEK. SHORTWAVE WILL EXIT THE AREA SATURDAY NIGHT WITH RIDGING
SUNDAY. TEMPERATURES WILL WARM NICELY SUNDAY WITH HIGHS WEATHER
PATTERN TO BECOME MORE ACTIVE THIS WEEKEND AND INTO NEXT WEEK.
SHORTWAVE WILL EXIT THE AREA SATURDAY NIGHT WITH RIDGING SUNDAY.
TEMPERATURES WILL WARM NICELY SUNDAY WITH HIGHS IN THE MID 40S TO
MID 50S EAST AND 30S WEST UNDER PARTLY CLOUDY SKIES. WINDS WILL
AGAIN BE A CONCERN SUNDAY MAINLY ACROSS THE WIND PRONE AREAS IN
SOUTHEAST WYOMING. GFS SHOWING A SOLID 50 TO 60 KTS OVER THESE AREAS
AT 18Z. DEPENDING ON WHICH WAY THE MODELS TREND...SOME OF THE
STRONGER WINDS COULD STRETCH FARTHER EAST...SUCH AS INTO CHEYENNE.

MORE SHORTWAVE ENERGY TO DIVE ACROSS THE AREA MONDAY. MINIMAL
SNOW ACCUMULATIONS A DECENT POSSIBILITY INTO THE MOUNTAINS MONDAY
WITH A FEW RAIN/SNOW SHOWERS INTO LOWER ELEVATIONS INCLUDING THE
PLAINS. NORTHWEST FLOW WILL REMAIN IN PLACE TUESDAY AND WEDNESDAY
WITH COOLER TEMPERATURES IN STORE ACROSS THE AREA. NOT LOOKING FOR
ANYTHING NEAR AS COLD AS A FEW WEEKS AGO...BUT CERTAINLY BELOW
NORMAL INTO MID AND LATE NEXT WEEK.

.LONG TERM...(WEDNESDAY THROUGH SUNDAY)
ISSUED AT 320 PM MST SUN MAR 1 2015

LONG RANGE MODELS IN FAIRLY GOOD AGREEMENT INTO NEXT WEEKEND...BUT
WITH ONE SUBSTANTIAL DIFFERENCE LATE-FRIDAY/SATURDAY COMPARED TO
YESTERDAY.

SOME FLURRIES ARE POSSIBLE AS THE STORM SYSTEM EARLY IN THE WEEK 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...AND BELIEVE THAT WESTERLY WINDS
AND THE 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. EXPECT HIGHS TO
RETURN TO THE 40S TO AROUND 50 BY FRIDAY AFTERNOON.

MODELS ARE NOW SHOWING A RETURN TO BELOW NORMAL TEMPERATURES FOR
NEXT WEEK AS A COLD FRONT QUICKLY DIVES SOUTHWARD FROM WESTERN
CANADA AS THE UPPER LEVEL TROUGH PUSHES THROUGH THE AREA ON
SATURDAY. HAD TO LOWER MAX TEMPERATURES SEVERAL DEGREES SINCE THE
GFS AND ECMWF ARE IN DECENT AGREEMENT...AS WELL AS THE LONG RANGE
ENSEMBLES. SOME LIGHT SNOW IS POSSIBLE BUT KEPT POP BELOW 15
PERCENT FOR NOW OUTSIDE OF THE MOUNTAINS.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING)
ISSUED AT 321 AM MST SUN MAR 1 2015

A WARM FRONT WILL SLOWLY MOVE NORTHWARD ACROSS THE AREA
TONIGHT...BRINGING ANOTHER ROUND OF SNOW TO AREAS ALONG I80. LOW
MVFR TO IFR CIGS/VSBYS ARE LIKELY AFTER 06Z TONIGHT FROM KLAR TO
POSSIBLY AS FAR EAST AS KSNY. WINDS WILL GENERALLY BE LIGHT
THROUGH THE TAF PERIOD BUT WILL INCREASE OUT OF THE SOUTH LATE
TONIGHT AND INTO EARLY MONDAY MORNING. SNOW WILL BRIEFLY END ALONG
AND EAST OF THE LARAMIE RANGE ON MONDAY BEFORE THE FRONT PUSHES
SOUTHWARD ONCE AGAIN MONDAY NIGHT. FURTHER WEST...A PROLONGED
PERIOD OF SNOW IS POSSIBLE AT KRWL WITH IFR OR LIFR CONDITIONS
BEGINNING EARLY MONDAY MORNING AND CONTINUING INTO TUESDAY.

&&

.FIRE WEATHER...
ISSUED AT 225 PM MST SUN MAR 1 2015

A LOW PRESSURE SYSTEM AND ASSOCIATED UPPER LEVEL TROUGH WILL
APPROACH FROM THE SOUTHWEST TONIGHT AND MONDAY...AND MOVE ACROSS
THE CENTRAL ROCKIES MONDAY NIGHT AND TUESDAY. SNOW WILL DEVELOP
TONIGHT ACROSS SOUTH CENTRAL WYOMING AND BECOME MORE WIDESPREAD
MONDAY AND MONDAY NIGHT. THE SNOW MAY BE HEAVY AT TIMES...
ESPECIALLY OVER THE HIGHER TERRAIN. THE SNOW WILL TAPER OFF
TUESDAY NIGHT. A ARCTIC COLD FRONT WILL PLUNGE SOUTH THROUGH THE
DISTRICT MONDAY NIGHT. BITTERLY COLD TEMPERATURES AND WIND CHILLS
WILL PREVAIL TUESDAY THROUGH WEDNESDAY BEFORE GRADUALLY MODERATING
TEMPERATURES LATE IN THE WEEK.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...WINTER STORM WARNING FROM 5 AM MONDAY TO 6 PM MST TUESDAY FOR
     WYZ111>114.

     WINTER STORM WATCH FROM MONDAY AFTERNOON THROUGH TUESDAY
     AFTERNOON FOR WYZ104-105-109-110.

NE...NONE.

&&

$$

SHORT TERM...SML
LONG TERM...TJT
AVIATION...TJT
FIRE WEATHER...MAJ/SML


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