Area Forecast Discussion
Issued by NWS Rapid City, SD

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000
FXUS63 KUNR 161728
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
1128 AM MDT WED APR 16 2014

.UPDATE...
ISSUED AT 1009 AM MDT WED APR 16 2014

MAIN BAND OF RAIN/SNOW HAS PUSHED INTO THE SRN CWA WITH
CONDITIONS DRYING TO THE NORTH. SHORT-RANGE MODELS CONTINUE TO
INDICATE NEXT WAVE SLIDING THROUGH MAY BRING SOME PRECIP PRIMARILY OVER
THE WRN CWA LATER TODAY. POPS HAVE BEEN ADJUSTED TO ADDRESS THIS
AND UPDATES HAVE BEEN SENT.

UPDATE ISSUED AT 610 AM MDT WED APR 16 2014

RAIN AND SNOW CONTINUES ACROSS LARGE PORTIONS OF WESTERN SOUTH
DAKOTA INTO THE WYOMING BLACK HILLS. SNOWFALL ACROSS THE BLACK
HILLS WILL CONTINUE EARLY THIS MORNING...BUT IS EXPECTED TO
DECREASE IN INTENSITY OVER THE NEXT COUPLE HOURS AS A SHORT WAVE
PUSHES THROUGH THE REGION. ACCUMULATING SNOW IS BEING LIMITED TO
THE HIGHER TERRAIN OF THE BLACK HILLS ABOVE 5500 TO 6000 FT.
ADDITIONAL ACCUMULATIONS OF 1 TO 2 INCHES IS EXPECTED TODAY IN
THESE LOCATIONS. HAVE UPDATED POPS TO REFLECT CURRENT TRENDS EARLY
THIS MORNING.

&&

.SHORT TERM...TODAY THROUGH THURSDAY NIGHT
ISSUED AT 311 AM MDT WED APR 16 2014

WATER VAPOR IMAGERY SHOWS A SHORTWAVE TROUGH CROSSING THE CWA AT
THIS TIME...AND WEAK RIDGING OVER THE PACIFIC NORTHWEST WITH A
SECONDARY TROUGH OVER CENTRAL ALBERTA. SURFACE ANALYSIS SHOWS 997MB
LOW PRESSURE NOW CENTERED JUST WEST OF KICR. A COOLER AND DRIER
AIRMASS IS OVER ERN SD WITH A BACKDOOR FRONT EXTENDING FROM K2X TO
KPHP TO SCNTRL SD. KUDX RADAR AND SURFACE OBS SHOWING RAIN FALLING
ACROSS THE PLAINS MAINLY ACROSS CENTRAL TO SW SD...AND SNOW
FALLING OVER HIGHER ELEVATIONS OF THE BLKHLS.

UPPER WAVE WILL CONTINUE ITS EASTWARD TRACK TODAY AND THE SURFACE
LOW PUSHES INTO SE SD. THE HEAVIEST PRECIP THIS MORNING WILL CROSS
SCNTRL SD AS IT MOVES INTO CNTRL/ERN SD. WITH ACTIVE FLOW
ALOFT...CHANCES FOR PRECIP WILL REMAIN ACROSS THE CWA. THE WEAK
FRONTAL BOUNDARY WILL STALL OVER FAR WRN SD. AS A SERIES OF UPPER
WAVES PUSH THROUGH THE AREA TODAY...NE WY TO THE BLKHLS AREA WILL BE
THE BEST CHANCES FOR SOME MORE PRECIP TODAY. PRECIP WILL BE RAIN OR
SNOW THIS MORNING...THEN ALL RAIN THIS AFTERNOON...AND CHANCES FOR
SNOW OVER THE HIGHER BLKHLS. OVERALL QPF AMOUNTS WILL BE RELATIVELY
LIGHT...SO ADDITIONAL SNOW ACCUMULATION OVER THE HILLS WILL BE
LIMITED TO AN INCH OR TWO TODAY. MAX TEMPS WILL BE MUCH COOLER THAN
AVERAGE WITH HIGHS IN THE UPPER 30S TO UPPER 40S...EXCEPT CLOSER TO
FREEZING OVER THE HIGHER BLKHLS. ECMWF AND GFS SHOW ACTIVE CYCLONIC
FLOW CONTINUING TONIGHT INTO THURSDAY WITH OCCASIONAL CHANCES FOR
LIGHT PRECIP. SURFACE HIGH WILL CROSS THE NORTHERN PLAINS EARLY
THURSDAY MORNING...AND SLIDE EAST DURING THE DAY. RETURN FLOW WILL
SET UP OVER THE AREA WITH WARMING TEMPS TO NEAR SEASONAL AVERAGE.


&&

.LONG TERM...FRIDAY THROUGH TUESDAY
ISSUED AT 311 AM MDT WED APR 16 2014

MODELS IN FAIRLY GOOD AGREEMENT THROUGH THE EXTENDED
PERIOD...ESPECIALLY THROUGH THE WEEKEND. SHORTWAVE RIDGE SLIDES
ACROSS THE AREA FRIDAY...AS UPPER TROF MOVES ACROSS THE NORTHERN
ROCKIES. SURFACE LOW TRACKS ALONG THE CANADIAN BORDER...WITH HIGH
PRESSURE MOVING EASTWARD INTO THE GREAT LAKES REGION. TIGHT
PRESSURE GRADIENT WITH STRONG PRESSURE FALLS OVER THE NORTHERN
PLAINS WILL RESULT IN WINDY CONDITIONS FRIDAY. 850 MB TEMPERATURES
SUPPORT HIGH IN THE 60S TO LOW 70S ACROSS NORTHEAST WYOMING INTO
SOUTHWEST SOUTH DAKOTA...SLIGHTLY ABOVE MOS GUIDANCE. COOLER
ACROSS NORTHWEST SOUTH DAKOTA WHERE LOW LEVEL INVERSION WILL LIMIT
MIXING. SHORTWAVE TROF LIFTS INTO CANADA FRIDAY NIGHT...AND MAY
BRING A FEW SHOWERS TO NORTHWEST SOUTH DAKOTA. FLAT UPPER LEVEL
RIDGE SETS UP ACROSS THE NORTHERN PLAINS FOR SUNDAY/MONDAY...AS
SOUTHERN STREAM TROF TRACKS ACROSS THE CENTRAL/SOUTHERN PLAINS.
DRY AND WARM WEATHER...WITH MOST LOCATIONS OUTSIDE OF THE BLACK
HILLS REACHING THE 70S BY MONDAY. LONGWAVE UPPER TROF DIGS ALONG
THE PACIFIC COAST EARLY NEXT WEEK...WITH STRONG RIDGE DEVELOPING
OVER THE PLAINS. COULD SEE A FEW 80S ON TUESDAY. MIDDLE OF NEXT
WEEK LOOKS INTERESTING AS UPPER TROF EJECTS ACROSS THE ROCKIES
WITH UPPER LOW CLOSING OFF...ALTHOUGH A LOT OF UNCERTAINTY IN
TIMING/TRACK.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY)
ISSUED AT 1120 AM MDT WED APR 16 2014

SCATTERED RAIN/SNOW SHOWERS WILL SHIFT SOUTHEAST OF THE AREA BY
EARLY AFTERNOON...BUT ADDITIONAL RAIN/SNOW SHOWERS MAY DEVELOP
OVER NORTHEAST WYOMING AND THE BLACK HILLS LATER THIS AFTERNOON
INTO THE EARLY EVENING. EXPECT LOCAL MVFR CEILINGS IN THESE AREAS
WITH MORE PERSISTENT IFR CEILINGS OVER THE BLACK HILLS. A SOLID
MVFR CLOUD DECK WILL MOVE SOUTH ACROSS NORTHWEST SOUTH DAKOTA AND
AFFECT MUCH OF THE REST OF WESTERN SOUTH DAKOTA THIS AFTERNOON AND
EVENING.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
WY...NONE.
&&

$$

UPDATE...77
SHORT TERM...13
LONG TERM...7
AVIATION...15





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