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000
FXUS65 KCYS 111729
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
1129 AM MDT TUE MAR 11 2014

.SHORT TERM...(TODAY THROUGH THURSDAY NIGHT)
ISSUED AT 317 AM MDT TUE MAR 11 2014

08Z SFC ANALYSIS SHOWS AREA OF LOW PRESSURE DEEPENING ACROSS NW
KANSAS/SW NEBRASKA...WHICH HAS TURNED WINDS NW-NE EVERYWHERE
EXCEPT IN CARBON COUNTY. THE WINDS SHIFT WILL OCCUR THERE BY
SUNRISE. THE BULK OF THE COLD AIR WAS LAGGING THIS INITIAL WIND
SHIFT HOWEVER...JUST NOW WORKING INTO NRN ZONES. IT IS IN THIS
LAGGING AREA WHERE THE BEST QG VERTICAL VELOCITIES ARE
LOCATED...WHICH MATCHES UP WELL WITH OBS AND REGIONAL RADAR TRENDS
THIS MORNING. THIS COLDER AIR MASS ASSOCIATED WITH THE SECOND
SURGE WILL BE THE MAIN FOCUS FOR SNOW DEVELOPMENT FROM NORTH TO
SOUTH DURING THE DAY TODAY. 00Z MODEL OUTPUT HAS DONE LITTLE TO
WARRANT ANY SIGNIFICANT ALTERATIONS TO THE SNOW AMOUNT FORECAST.
STILL THINKING GENERALLY 1 TO 2 INCHES IN LOWER ELEVATIONS...WITH
PERHAPS UP TO 3 IN LOCALIZED AREAS. SNOWY...SIERRA MADRE AND
NORTHERN LARAMIE RANGES SHOULD PICK UP WIDESPREAD 5 TO 10
INCHES...WITH LOCALLY HIGHER AMOUNTS POSSIBLE. ADDITIONALLY...
NORTH WINDS WILL GUST TO 35 TO 45 MPH TODAY CREATING AREAS OF
BLOWING AND DRIFTING SNOW ACROSS THE ENTIRE AREA. THE WESTERN
NEBRASKA PANHANDLE MAY NR WIND ADVISORY CRITERIA AS 3-HOURLY
PRESSURE RISES WILL BE 5-6MB FOR A TIME AROUND MIDDAY. HOWEVER AM
NOT CONFIDENT ENOUGH TO HOIST AT THIS TIME. SNOW WILL COME TO AN
END BY LATE AFTERNOON...GIVING WAY TO CLEARING SKIES TONIGHT. AS
FOR TEMPERATURES TODAY...MOST AREAS HAVE ALREADY SEEN THEIR HIGHS
THIS MORNING WITH COOLING INTO THE 20S/30S ANTICIPATED THRU THE
REST OF THE DAY.

THE TROUGH WILL SPLIT ON WEDNESDAY SENDING A CUT-OFF TO THE
DESERT SW AND THE NRN STREAM ENERGY TO THE OHIO RIVER VALLEY.
HEIGHTS WILL RISE AND WITH NEARLY FULL INSOLATION...HIGHS WILL
RETURN BACK TO NR 40F WEST OF THE LARAMIE RANGE AND UPPER 40S
EAST.  THE NEXT SHORTWAVE WILL BE DRY AS IT PHASES WITH THE
OPENING LOW OVR THE DESERT SOUTHWEST ON THURSDAY.
WINDS...ESPECIALLY OVR THE WIND CORRIDOR WILL BECOME BREEZY OUT
AHEAD OF IT FOR THURSDAY. HIGH TEMPERATURES WILL BE EVEN WARMER ON
THURSDAY WITH 40S WEST AND 50S TO NR 60 EAST OF THE LARAMIE RANGE.

.LONG TERM...(FRIDAY THROUGH MONDAY)
ISSUED AT 317 AM MDT TUE MAR 11 2014

SYNOPTICALLY...MODELS IN DECENT AGREEMENT THROUGH
SUNDAY...THOUGH DIVERGE ON MONDAY...AS THE ECMWF HAS A DEEPER
AMPLITUDE SHORTWAVE TROUGH OVER THE NORTHERN ROCKIES...WHILE THE GFS
KEEPS THE TROUGH JUST OVER MONTANA AND OF LOWER AMPLITUDE.

FRIDAY...QUITE DAY WEATHERWISE WITH NORTHWEST FLOW ALOFT AND MINIMAL
LOW AND MID LEVEL MOISTURE. BREEZY PER PROGGED GRADIENTS.

SATURDAY...FAST MOVING POSITIVELY TILTED SHORTWAVE TROUGH ALOFT
MOVES OVERHEAD...PRODUCING A QUICK LOW QPF PRECIPITATION EVENT AND
COOLER TEMPERATURES IN THE WAKE OF A COLD FRONT.

SUNDAY...RIDGING ALOFT TAKES OVER PRODUCING A DRY AND WARMER DAY
WITH SURFACE LEE TROUGHING ESTABLISHING ITSELF.

MONDAY...STARK CONTRAST IN MODEL SOLUTIONS. IF THE ECMWF SOLUTION
VERIFIES...WE WILL SEE A STRONG COLD FRONTAL PASSAGE IN THE
AFTERNOON WITH SCATTERED SNOW SHOWERS. IF THE GFS SOLUTION VERIFIES
WITH A LOWER AMPLITUDE SHORTWAVE TROUGH OVER MONTANA...WE WILL HAVE
A DECENT SURFACE LEE TROUGH FORMATION WITH MILD TEMPERATURES SOARING
INTO THE 50S AND 60S. FOR NOW...WILL SIDE CLOSER TO THE WARMER AND
DRIER GFS SOLUTION.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY MORNING)
ISSUED AT 1129 AM MDT TUE MAR 11 2014

WIDESPREAD MVFR/IFR CIGS AND VSBYS OVER ALL TERMINALS EARLY THIS
AFTERNOON THEN CONDITIONS EXPECTED TO IMPROVE FROM NORTH TO SOUTH
LATER THIS AFTERNOON INTO THIS EVENING WITH VFR EXPECTED OVERNIGHT
AND WEDNESDAY. GUSTY NORTH WINDS WILL DECREASING LATE THIS AFTERNOON.

&&

.FIRE WEATHER...
ISSUED AT 317 AM MDT TUE MAR 11 2014

COLD FRONT WILL PUSH SOUTH OF THE AREA TODAY BRINGING ANOTHER ROUND
OF  ACCUMULATING SNOW AND COLDER CONDITIONS TO THE DISTRICT. LOWER
ELEVATIONS WILL GENERALLY RECEIVE 1 TO 3 INCHES WITH 5 TO 10 INCHES
ANTICIPATED OVR THE SNOWY AND SIERRA MADRES. WARMING AND DRIER
CONDITIONS ARE ANTICIPATED FOR WEDNESDAY THROUGH THE END OF THE WEEK.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...WINTER WEATHER ADVISORY UNTIL 6 PM MDT THIS EVENING FOR WYZ103-
     112-114.

NE...NONE.
&&

$$

SHORT TERM...HAHN
LONG TERM...RUBIN
AVIATION...RE
FIRE WEATHER...HAHN