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000
FXUS63 KUNR 281038
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
338 AM MST FRI FEB 28 2014

.SHORT TERM...TODAY THROUGH SATURDAY NIGHT
ISSUED AT 303 AM MST FRI FEB 28 2014

UPPER LEVEL ANALYSIS HAS DEEP LOW OVER THE HUDSON BAY WITH WEAK
CYCLONIC FLOW ACROSS THE NORTHERN CONUS. ANOTHER UPPER LOW IS JUST
OFF THE CALIFORNIA COAST WITH SHARP RIDGE ENTERING THE GREAT BASIN
AREA. WEAK SHORTWAVE ENERGY IN CYCLONIC FLOW IS MOVING EAST ACROSS
SOUTH CENTRAL MONTANA...SPREADING SNOW INTO NORTHEAST WYOMING AND
WESTERN SOUTH DAKOTA. AT THE SURFACE...ARCTIC COLD FRONT IS
CROSSING NORTHEAST WYOMING AND WESTERN SOUTH DAKOTA RIGHT NOW.
NORTHWEST WINDS BEHIND THE FRONT HAVE BEEN GUSTING TO NEAR 40 MPH.
TEMPERATURES ARE IN THE 20S AND 30S AS ATMOSPHERE MIXES NEAR THE
FRONT...WITH TEMPS FALLING QUICKLY TO THE NORTH OF THE CWA.

TODAY...ARCTIC FRONT WILL MAKE IT THROUGH MUCH OF THE FORECAST
AREA BY DAYBREAK AS WEAK SHORTWAVE ENERGY CROSSES THE NORTHERN
PLAINS. EXPECT GUSTY NORTHWEST WINDS AND AREAS OF SNOW THIS
MORNING ACROSS MUCH OF NORTHEAST WYOMING AND FAR WESTERN SOUTH
DAKOTA...WITH ACCUMULATIONS OF AN INCH OR SO POSSIBLE. BIGGEST
PROBLEM THIS MORNING WILL BE REDUCED VISIBILITIES WHERE SNOW AND
WIND COMBINE. NORTHERLY WINDS SHOULD DIMINISH SOMEWHAT BY
AFTERNOON. BEST SNOW CHANCES REMAIN OVER WESTERN AREAS THROUGH THE
AFTERNOON. MORNING TEMPS WILL LIKELY BE MAX TEMP FOR THE DAY AS
ARCTIC AIR FILTERS INTO THE AREA.

TONIGHT...ADDITIONAL SNOW WILL DEVELOP TONIGHT AS NEXT UPPER
SHORTWAVE CROSSES THE NORTHERN PLAINS. AGAIN...BEST SNOW CHANCES
WILL BE ACROSS NORTHEAST WYOMING TO SOUTHWESTERN SD AND THE BLACK
HILLS AREA. SNOW RATIOS LOOK TO BE QUITE HIGH...AROUND 20:1 OR
SLIGHTLY HIGHER. WITH THE AMPLE AVAILABLE MOISTURE...SNOWFALL
AMOUNTS OF 2 TO 4 INCHES ARE POSSIBLE ACROSS THESE AREAS BY
EARLY SATURDAY MORNING. LOW TEMPERATURES WILL FALL BELOW ZERO
ACROSS THE ENTIRE FORECAST AREA.

SATURDAY...SNOW WILL CONTINUE AS ARCTIC AIR REMAINS OVER THE
NORTHERN PLAINS. ANOTHER 2 TO 3 INCHES OF SNOW WILL BE POSSIBLE
ACROSS NORTHEAST WYOMING AND THE BLACK HILLS AREA. A WINTER
WEATHER ADVISORY WILL BE IN EFFECT FOR THESE AREAS...FROM FRIDAY
NIGHT THROUGH SATURDAY NIGHT...WITH 4 TO 7 INCHES OF TOTAL
SNOWFALL EXPECTED. IN ADDITION TO THE SNOW...TEMPERATURES WILL
STRUGGLE TO RISE ABOVE ZERO DURING THE DAY...WITH MANY LOCATIONS
REMAINING BELOW ZERO. TEMPERATURES WILL FALL WELL BELOW ZERO
SATURDAY NIGHT AS SNOW SLOWLY TAPERS OFF.


&&

.LONG TERM...SUNDAY THROUGH THURSDAY
ISSUED AT 303 AM MST FRI FEB 28 2014

EXTENDED MODELS IN DECENT AGREEMENT THROUGH THE UPCOMING
WEEK...WITH FLAT RIDGE OVER THE NORTHERN ROCKIES WITH FAST MOVING
EMBEDDED WAVES.

1040MB ARCTIC HIGH SETTLES IN OVER THE DAKOTAS ON SUNDAY...WITH
LAST SEVERAL MODEL RUNS TRENDING DRIER DURING THE DAY. SINGLE DIGIT
HIGHS EXPECTED FOR MOST LOCATIONS. TEMPERATURE TREND FOR THE REST OF
THE EXTENDED WILL BE UPWARDS. OPERATIONAL RUNS OF GFS/ECMWF CONTINUE
TO SHOW AGGRESSIVE WARM UP BY MID WEEK...WITH 850MB TEMPERATURES
APPROACHING +10C. GEFS MEMBERS SHOWING A 15-20C SPREAD IN 850MB
TEMPERATURES...BUT MAINLY INFLUENCED BY ONE MEMBER HOLDING ON TO THE
EXTREME COLD. FORECAST TEMPERATURES HAVE BEEN ADJUSTED UPWARDS.
WITH FAST UPPER FLOW...UNCERTAINTY EXISTS WITH TIMING OF EMBEDDED
WAVES.

&&

.AVIATION...FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING
ISSUED AT 303 AM MST FRI FEB 28 2014

STRONG ARCTIC FRONT WILL MOVE THROUGH THE AREA EARLY THIS
MORNING...WITH MVFR/IFR CIGS AND STRONG NORTHWEST WINDS. AREAS OF
SNOW WILL RESULT IN IFR/LIFR VSBY. WIDESPREAD SNOW EXPECTED LATER
THIS AFTERNOON THROUGH TONIGHT...WITH IFR/LIFR CONDITIONS.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO 5 AM MST
     SUNDAY FOR SDZ012-024>031-041-042-072>074.

WY...WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO 5 AM MST
     SUNDAY FOR WYZ054>058-071.

&&

$$

SHORT TERM...15
LONG TERM...7
AVIATION...7