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000
FXUS65 KCYS 062216
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
316 PM MST THU MAR 6 2014

.SHORT TERM...(THIS EVENING THROUGH FRIDAY NIGHT)
ISSUED AT 300 PM MST THU MAR 6 2014

TONIGHT...NEXT POSITIVELY TILTED SHORTWAVE TROUGH APPROACHES WYOMING
WITH ASSOCIATED BAROCLINIC BAND AND COLD FRONT MOVING ACROSS OUR
COUNTIES. COMBINATION OF A DEEPENING MOIST LAYER...AND LIFT PROVIDED
BY DYNAMICS AND OROGRAPHICS/UPSLOPE WILL PRODUCE INCREASING AREAL
SNOW COVERAGE. WITH DURATION OF SNOW TONIGHT AND INTO FRIDAY NIGHT...
WE EXPECT THE SNOWY AND SIERRA MADRE RANGES TO RECEIVE SOME 6 TO 10
INCHES OF SNOW...THUS WE HAVE ISSUED A WINTER WEATHER ADVISORY.

FRIDAY...SHORTWAVE TROUGH ALOFT MOVES ACROSS OUR COUNTIES...WITH
GREATEST SNOW COVERAGE SOUTH OF A RAWLINS TO SCOTTSBLUFF LINE
CLOSEST TO DEEPEST MOISTURE AND DYNAMICS. GUIDANCE TEMPERATURES LOOK
TOO COLD...ESPECIALLY ACROSS OUR SOUTHERN COUNTIES WHERE CLOUDS AND
PRECIPITATION WILL HOLD TEMPERATURES DOWN.

FRIDAY NIGHT...AREAL SNOW COVERAGE WILL DECREASE FROM NORTH TO SOUTH
AS THE SHORTWAVE TROUGH ALOFT MOVES SOUTH OF OUR COUNTIES. WITH THE
SNOWFALL EVENT...WE ARE EXPECTING A TOTAL OF 6 TO 10 INCHES OVER OUR
SNOWY AND SIERRA MADRE RANGES...WITH 1 TO 3 INCHES TOTAL AT LOWER
ELEVATIONS WEST OF INTERSTATE 25 AND 3 TO 5 INCHES OVER THE SOUTHERN
LARAMIE RANGE.

.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 315 PM MST THU MAR 6 2014

LOOKING AT A TYPICAL MARCH PATTERN FOR SOUTHEAST WY AND WESTERN
NEBRASKA PANHANDLE WITH ONE PACIFIC STORM SYSTEM EXITING EARLY
SATURDAY AND THE NEXT LATE MONDAY THROUGH WEDNESDAY. IN BETWEEN
WILL BE A DRY AND MILD PERIOD. SO FORECAST CHALLENGES WILL FOCUS
ON WINDS...TEMPERATURES AND PRECIPITATION CHANCES.

THE PACIFIC TROUGH RESPONSIBLE FOR THE INCLEMENT WEATHER FRIDAY
NIGHT MOVES INTO THE GREAT PLAINS SATURDAY WITH AN UPSTREAM RIDGE
TRANSLATING SOUTHEAST TOWARD THE SOUTHWEST CONUS. THE FLOW ALOFT
WILL BACK FROM NORTHWEST TO WEST SUNDAY. THIS PATTERN SHIFT WILL
RESULT IN A PERIOD OF DRIER AND WARMER THAN NORMAL TEMPERATURES.
HIGHS SATURDAY MAY BE A TAD COOLER THAN GUIDANCE AS A RESULT OF AN
EXISTING SNOW COVER. WESTERLY WINDS WILL BE LIGHTER SATURDAY...BUT
INCREASE SATURDAY NIGHT AND SUNDAY WITH A TIGHTENING PRESSURE
GRADIENT IN ADVANCE OF THE NEXT TROUGH ENTERING THE PACIFIC
NORTHWEST. 700MB WINDS RAMP UP TO 50-60 KT BY 12Z SUNDAY. SHOULD
THESE MODEL TRENDS CONTINUE...COULD BE LOOKING AT HIGH WIND
HEADLINES FOR OUR NORMALLY WIND PRONE ZONES IN SOUTHEAST WY. IT
WILL BE MUCH WARMER SUNDAY WITH INCREASING DOWNSLOPE FLOW EAST OF
THE LARAMIE RANGE PUSHING THE MERCURY INTO THE 60S.

THERE ARE SOME DIFFERENCES BETWEEN THE GFS AND ECMWF REGARDING
THE NEXT PACIFIC STORM MOVING INTO THE WEST...ESPECIALLY TUESDAY
AND WEDNESDAY. MONDAY WILL NOT BE AS WINDY AS SUNDAY...BUT WILL BE
QUITE MILD WITH 50S TO LOWER 60S. CLOUDS WILL INCREASE FROM WEST
TO EAST...WITH SHOWERS DEVELOPING WEST OF A LARAMIE TO DOUGLAS
LINE MONDAY AFTERNOON. PRECIPITATION QUICKLY SPREADS EAST ONTO THE
PLAINS MONDAY NIGHT WITH COLDER TEMPERATURES BEHIND A PACIFIC COLD
FRONT. RAIN WILL CHANGE TO SNOW AT THAT TIME...WITH SOME
ACCUMULATION POSSIBLE. LOWER ELEVATIONS MAY SEE RAIN/SNOW MIX
CHANGEOVER TO RAIN TUESDAY AS TEMPERATURES RISE TO AROUND 40.
THE GFS IS TRENDING SLOWER THAN THE ECMWF WITH THE EASTWARD
PROGRESSION OF THE TROUGH. BOTH MODELS KEEP SOME QPF LINGERING
INTO WEDNESDAY MORNING BEFORE DRYING. HIGH TEMPERATURES WEDNESDAY
WILL BE SIMILAR TO TUESDAY. NORTHWEST FLOW ALOFT THURSDAY WITH
BREEZY DOWNSLOPE WINDS WILL MODERATE TEMPERATURES TO SEASONAL
NORMALS.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY MORNING)
ISSUED AT 1052 AM MST THU MAR 6 2014

WYOMING TAFS...VFR THROUGH 00Z WITH STRONG WEST WINDS GUSTING TO
35 KNOTS...WITH MOUNTAIN WAVE TURBULENCE...LEE EDDY EFFECTS AND
ROTOR CLOUD DEVELOPMENT. AFTER 00Z...CEILINGS AND VISIBILITIES
GRADUALLY DECREASING WITH IFR AND MVFR DEVELOPING IN SNOW AND
FOG...ESPECIALLY AFTER 12Z. MOUNTAINS BECOMING OBSCURED TONIGHT
AND FRIDAY.

NEBRASKA TAFS...VFR WITH SCATTERED TO BROKEN CLOUDS AT 0R ABOVE
10000 FEET AGL THROUGH 00Z...THEN CEILINGS LOWERING OVERNIGHT
WITH IFR VISIBILITIES DEVELOPING IN RAIN...FOG AND LOW CLOUDS A
AFTER 09Z.

&&

.FIRE WEATHER...
ISSUED AT 215 PM MST THU MAR 6 2014

NO FIRE WEATHER ISSUES THROUGH SATURDAY. AFTER A MILD AND BREEZY
AFTERNOON...THE NEXT PACIFIC STORM SYSTEM AND COLD FRONT WILL
BRING A RETURN TO UNSETTLED AND COLDER WEATHER TONIGHT THROUGH
FRIDAY NIGHT. WIDESPREAD PRECIPITATION...MOSTLY IN THE FORM OF
SNOW WILL FALL. SNOW ACCUMULATIONS WILL VARY FROM A FEW INCHES
OVER THE PLAINS TO AS MUCH AS 6 TO 10 INCHES OVER THE MOUNTAINS.
DRIER...BREEZY AND MILDER WEATHER WILL RETURN SATURDAY AND SUNDAY
WITH MINIMUM RELATIVE HUMIDITIES FROM 20 TO 30 PERCENT. ANOTHER
PACIFIC STORM SYSTEM MAY BRING A PROLONGED PERIOD OF COLDER
TEMPERATURES AND PRECIPITATION EARLY NEXT WEEK.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO 6 AM MST
     SATURDAY FOR WYZ112-114.

NE...NONE.
&&

$$

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