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000
FXUS65 KCYS 032231
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
331 PM MST MON MAR 3 2014

.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY NIGHT)
ISSUED AT 330 PM MST MON MAR 3 2014

AFTERNOON WATER VAPOR IMAGERY REVEALED A MODERATELY AMPLIFIED
PROGRESSIVE LARGE SCALE FLOW ACROSS THE NATION. TROUGHS WERE LOCATED
OVER THE OH/TN VALLEYS...CENTRAL PLAINS TO SOUTHERN ROCKIES AND
EASTERN PACIFIC. RIDGES WERE SITUATED OFF THE ATLANTIC COAST...MIDWEST
AND INTERMOUNTAIN WEST. A WARM FRONT WAS ANALYZED FROM CENTRAL MT
THRU NORTHEAST WY...NE PANHANDLE AND EASTERN CO. A BROAD WEAK RIDGE
ENCOMPASSED AREAS FROM THE CENTRAL/SOUTHERN ROCKIES WESTWARD.
TEMPERATURES WERE MOSTLY IN THE 30S AND 40S. WESTERLY WINDS WERE
GUSTING BETWEEN 25 AND 45 MPH ACROSS MUCH OF SOUTHEAST WY. LIGHTER
WINDS PREVAILED ACROSS WESTERN NE. INTERVALS OF MID AND HIGH CLOUDS
DOTTED THE REGIONAL SKYSCAPE.

SHORT TERM FORECAST CHALLENGES WILL FOCUS ON PRECIPITATION...WINDS
AND TEMPERATURES. WEAK RIDGING ALOFT WILL TRANSLATE EAST ACROSS
THE CWA TONIGHT. THERE WILL BE ENOUGH LOW/MID LEVEL MOISTURE FOR
LIGHT SNOWFALL OVER THE SOUTHERN MOUNTAINS. TEMPERATURES WILL BE
MILDER UNDER THE RIDGE WITH 700MB TEMPERATURES STEADY AROUND -3C.
GUSTY WESTERLY WINDS OF 25 TO 45 MPH WILL CONTINUE TONIGHT FOR
WIND PRONE AREAS OF SOUTHEAST WY.

A SHORTWAVE DISTURBANCE WILL BE MOVING INTO WY BY TUESDAY MORNING...
AND INTENSIFY AS IT TRANSITS THE STATE TUESDAY AFTERNOON AND INTO
THE HIGH PLAINS TUESDAY NIGHT. NOT MUCH IN THE WAY OF FRONTOGENESIS
OR LARGE SCALE LIFT WITH THIS FEATURE...HOWEVER SUFFICIENT MOISTURE
AND UPSLOPE WILL BE PRESENT FOR SIGNIFICANT SNOW ACCUMULATIONS OVER
HIGHER ELEVATIONS WEST OF THE LARAMIE RANGE. THE HEAVIER ACCUMULATIONS
LOOK FAVORED OVER THE SIERRA MADRE RANGE WHERE 6 TO 8 INCHES IS
EXPECTED. THEREFORE...HAVE ISSUED A WINTER WEATHER ADVISORY FOR
SNOW FROM LATE TUESDAY MORNING THROUGH TUESDAY NIGHT. WINDS WILL
NOT BE AS GUSTY...GENERALLY 15 TO 25 MPH. HIGH TEMPERATURES TUESDAY
WILL BE SIMILAR TO TODAY WITH 30S AND 40S. PRECIPITATION ACROSS
THE PLAINS WILL BE RAIN OR RAIN/SNOW MIX TUESDAY AFTERNOON THEN
CHANGE TO SNOW TUESDAY EVENING AS COLDER AIR SPREADS EAST.
ACCUMULATIONS WILL BE LIGHT...MAINLY AN INCH OR LESS. THE SNOW TAPERS
OFF AND ENDS BY WEDNESDAY MORNING WITH THE DEPARTURE OF THE SHORTWAVE.

WEDNESDAY AND WEDNESDAY NIGHT WILL BE DRY. DAYTIME HIGHS WILL BE
SEASONAL WITH WARMER THAN NORMAL NIGHTTIME LOWS. A FASTER WESTERLY
FLOW ALOFT WILL SPREAD EAST INTO WY LATE WEDNESDAY AND CONTINUE
WEDNESDAY NIGHT. 700MB WINDS INCREASE FROM 50 TO 60 KT WEDNESDAY
NIGHT IN THE VICINITY OF THE LARAMIE RANGE. COULD BE LOOKING AT
HIGH WIND HIGHLIGHTS AT THAT TIME.

.LONG TERM...(THURSDAY THROUGH MONDAY)
ISSUED AT 245 PM MST MON MAR 3 2014

CONFIDENCE IN RESPECTIVE MODEL SOLUTIONS IS MODERATE TO HIGH...SINCE
THE MODELS ARE IN REASONABLY CLOSE AGREEMENT SYNOPTICALLY AT 500
MB.

THURSDAY...FLOW ALOFT BECOMES ZONAL...WEST TO EAST. NAM SHOWS A DECENT
SLUG OF LOW AND MID LEVEL MOISTURE ADVECTING EASTWARD ACROSS CARBON
COUNTY...AND ESPECIALLY THE SNOWY AND SIERRA MADRE RANGES OF SOUTHERN
CARBON COUNTY...WHILE THE OTHER MODELS ARE LESS BULLISH ON PRECIPITATION.
WILL LATCH ONTO THE NAM THIS TIME...AS IT TYPICALLY IS TOO LOW ON
QPF COMPARED TO THE GFS AND ECMWF...AND THE CURRENT WATER VAPOR LOOP
DOES SHOW A DECENT MOISTURE FEED MOVING ASHORE FROM THE PACIFIC INTO
NORTHERN CALIFORNIA...LENDING MORE VALIDITY TO THE WETTER NAM SOLUTION.
IN EITHER EVENT...DOWNSLOPING IN THE LOW LEVELS AND SNOW SHADOWING...
WILL KEEP EVERYWHERE ELSE DRY.

ASSUMING MINIMAL MIDDLE AND HIGH CLOUD OPACITY...THICKNESS...BASED
ON PROJECTED THICKNESSES...DOWNSLOPE WINDS AND EXPERIENCE...WILL
BOOST MAXIMUM TEMPERATURES CLOSE TO GFS MEX GUIDANCE AS DOWNSLOPE
WINDS IN THE LOW LEVELS CONTRIBUTE GREATLY TO WARMING POTENTIAL.

FRIDAY...PROGRESSIVE POSITIVELY TILTED SHORTWAVE TROUGH ALOFT AND
ITS ASSOCIATED BAROCLINIC BAND AND COLD FRONT MOVE ACROSS WYOMING
AND COLORADO...SPREADING SNOWS FROM WEST TO EAST...WITH GREATEST
AREAL COVERAGE ACROSS THE NORTHERN LARAMIE...SNOWY AND SIERRA MADRE
RANGES OF CARBON AND ALBANY COUNTIES...THOUGH MOST LOCALES SHOULD AT
LEAST SEE SCATTERED COVERAGE OF SNOW SHOWERS WITH THE PROJECTED LOW
AND MID LEVEL MOISTURE...AND PROJECTED DYNAMIC...OROGRAPHIC AND
UPSLOPE LIFT. CONSIDERABLY COLDER IN THE WAKE OF THE POTENT COLD
FRONT AND CLOUD COVER.

SATURDAY...DRIER WITH A SLOW WARMING TREND AS RIDGING ALOFT MOVES
ACROSS OUR REGION...THOUGH MAXIMUM TEMPERATURES WILL BE TEMPERED BY
NORTH AND NORTHWEST FLOW ALOFT.

SUNDAY...QUITE PLEASANT DAY FOR MILD WEATHER OUTDOOR ENTHUSIASTS AS
THE FLOW ALOFT TURNS ZONAL...WEST TO EAST...AND A DECENT SURFACE LEE
TROUGH DEVELOPS FROM EASTERN MONTANA...THROUGH EASTERN WYOMING TO
EASTERN COLORADO. BASED ON PROJECTED 700 MB TEMPERATURES NEAR 4
CELSIUS AND 1000-500 MB THICKNESSES NEAR 5610 METERS...AS WELL AS
COPIOUS SUNSHINE AND DOWNSLOPE WARMING...MAXIMUM TEMPERATURES
EXPECTED TO EASILY SOAR INTO THE 50S WEST OF INTERSTATE 25...WITH
MAINLY BALMY 60S EAST OF INTERSTATE 25.

MONDAY...NEXT PROGRESSIVE SHORTWAVE TROUGH ALOFT MOVES ACROSS
MONTANA AND WYOMING. THERE ARE DECENT DIFFERENCES BETWEEN THE GFS
AND ECMWF...AS THE ECMWF SHOWS MORE AMPLITUDE WITH THE SHORTWAVE
TROUGH THAN DOES THE GFS. THE ECMWF DEPICTS MORE WIDESPREAD
PRECIPITATION THAN THE GFS SOLUTION. WITH THIS BEING OUR DAY 7 AND
SHORTWAVE TIMING AND INTENSITY THIS FAR OUT QUITE SKETCHY...WILL
BLEND WITH OUR NEIGHBORING OFFICES GRIDDED FORECASTS AND PAINT
SCATTERED POPS NEAR OUR MOUNTAINS WEST OF INTERSTATE 25. COOLER IN
THE WAKE OF THE SHORTWAVE TROUGH ALOFT AND COLD FRONTAL PASSAGE.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY MORNING)
ISSUED AT 1115 AM MST MON MAR 3 2014

WYOMING AERODROMES...SCATTERED TO BROKEN MIDDLE AND HIGH CLOUDS
AT OR ABOVE 10000 FEET AGL. AT RAWLINS...AFTER 12Z...SCATTERED
SNOW SHOWERS PRODUCING IFR VISIBILITIES AND MVFR CEILINGS WITH
THE NEARBY MOUNTAINS OBSCURED. WINDS GUSTING 20 TO 38 KNOTS AT
VARIOUS TIMES...PRODUCING LOCALIZED MOUNTAIN TURBULENCE AND LEE
EDDY AND ROTOR CLOUD EFFECTS.

NEBRASKA AERODROMES...SCATTERED TO BROKEN CLOUDS AT OR ABOVE
8000 FEET AGL. OCCASIONAL WINDS GUSTING UP TO 20 KNOTS AT SIDNEY
THROUGH 00Z.

&&

.FIRE WEATHER...
ISSUED AT 245 PM MST MON MAR 3 2014

FIRE WEATHER CONCERNS WILL BE MINIMAL THIS WEEK WITH AN EXISTING
SNOW PACK AND CHANCES FOR ADDITIONAL SNOW. A PACIFIC WEATHER SYSTEM
WILL BRING RAIN AND SNOW TUESDAY AND TUESDAY NIGHT. DRIER AND WARMER
CONDITIONS WIL RETURN WEDNESDAY AND THURSDAY... FOLLOWED BY A
STRONGER PACIFIC STORM SYSTEM ON FRIDAY AND SATURDAY...WITH SNOW
AND COLDER TEMPERATURES.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...WINTER WEATHER ADVISORY FROM 11 AM TUESDAY TO 5 AM MST WEDNESDAY
     FOR WYZ112.

NE...NONE.
&&

$$

SHORT TERM...JAMSKI
LONG TERM...RUBIN
AVIATION...RUBIN
FIRE WEATHER...JAMSKI/CLAYCOMB