Area Forecast Discussion
Issued by NWS Rapid City, SD

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000
FXUS63 KUNR 212152
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
252 PM MST FRI NOV 21 2014

.SHORT TERM...THIS EVENING THROUGH SATURDAY NIGHT
ISSUED AT 251 PM MST FRI NOV 21 2014

MILD CONDITIONS WILL CONTINUE THROUGH SATURDAY AS DRY
WESTERLY PAC FLOW REMAINS IN PLACE. WEAK MID LEVEL IMPULSE IS
CURRENTLY MOVING THROUGH THE REGION...SUPPORTING A SFC TROUGH INTO
THE AREA. THIS SYSTEM WILL SUPPORT LITTLE TO NO CAA...KEEPING
THERMAL FIELDS BASICALLY UNALTERED ON IT/S BACKSIDE. ATTENTION TURNS
TOWARD A STRONG MID LEVEL TROUGH NOW ENTERING THE PAC NW. THIS
SYSTEM WILL CROSS THE NORTHERN ROCKIES AND AMPLIFY PER A STAUNCH
150+ KNOT UPPER LEVEL JET...ENTERING THE NORTHERN PLAINS LATER
SATURDAY. THIS SYSTEM WILL SUPPORT STRONG LL PRESSURE
FALLS...AND A DEEPENING SFC CYCLONE OVER THE REGION BY SAT
NIGHT. THIS SYSTEM WILL QUICKLY PROGRESS THROUGH THE REGION SAT
NIGHT...SUPPORTING FRONTOGENETICAL FORCING AND RESULTING RAIN AND
SNOW...ESP OVER NE WY AND THE NORTHERN HILLS. ANY SHOWERS WILL
LIKELY START AS RAIN OR A RAIN SNOW/MIX...WITH PRECIP TYPE
TRANSITIONING TO ALL SNOW SAT NIGHT. OVERALL...PRECIP CHANCES
REMAIN IN THE SCT-ISOLD RANGE...GIVEN LACK OF SIG FOCUS UVM. ANY
SNOW ACCUMS ARE EXPECTED TO BE AN INCH OR LESS...OUTSIDE OF THE
NORTHERN HILLS WHERE A COUPLE INCHES WILL BE POSSIBLE.

AS FOR TEMPS...PAC NW SYSTEM WILL SUPPORT RE-NEWED DOWNSTREAM
RIDGING WITH AN ASSOCIATED THERMAL RIDGE...WHICH WILL ADVECT OVER
THE REGION SAT. GIVEN CYCLOGENESIS AND INCREASED SFC PRESSURE
FALLS...WESTERLY WINDS WILL INCREASE OVER THE REGION
SAT...SUPPORTING GOOD MIXING. THIS WILL ALLOW ANOTHER WARM DAY
ACROSS THE AREA...WITH 40S AND 50S COMMON ESP...WARMEST ACROSS THE
EASTERN BLACK HILLS AND SCENTRAL SD. WINDS WILL INCREASE SAT EVE
AHEAD OF THE SFC TROUGH IN THE FAVORED DOWNSLOPE AREAS ACROSS THE
BLACK HILLS...WITH WINDS INCREASING EVERYWHERE ACROSS THE REGION
LATE SAT NIGHT...POST FRONTAL. STRONG NW WINDS WILL DEVELOP AS
STAUNCH CAA COMBINES WITH SFC PRESSURE RISES AND INCREASING BL FLOW.
HAVE INCREASED WINDS SOME SAT NIGHT.

&&

.LONG TERM...SUNDAY THROUGH FRIDAY
ISSUED AT 251 PM MST FRI NOV 21 2014

AN ACTIVE PATTERN ASSOCIATED WITH DEEP CYCLONIC FLOW
ALOFT WILL CONTINUE ACROSS THE NORTH CENTRAL CONUS THROUGH EARLY
NEXT WEEK. A TIGHT PRESSURE GRADIENT ON THE BACKSIDE OF LOW PRESSURE
PUSHING INTO THE UPPER MIDWEST WILL BRING VERY WINDY CONDITIONS TO
MUCH OF THE WESTERN SD PLAINS ON SUNDAY. THERE IS POTENTIAL FOR
WARNING CRITERIA WINDS SUNDAY AFTERNOON ACROSS NORTHWEST AND WEST
CENTRAL SD. WILL LET NEXT SHIFT HAVE ANOTHER LOOK AND SEE IF A WATCH
IS NEEDED. UPSLOPE ENHANCED SNOW SHOWERS WILL MAINLY AFFECT THE
NORTHERN BLACK HILLS ON SUNDAY...WITH SOME LIGHT ACCUMULATIONS
LIKELY. WINDS WILL REMAIN BREEZY ON MONDAY. ADDITIONAL WEAK
DISTURBANCES IN NORTHWEST FLOW WILL BRING CLOUDS AND CHANCES FOR
SNOW SHOWERS AT TIMES THROUGH WEDNESDAY.

THERE IS STILL UNCERTAINTY TOWARD THE LATTER PART OF NEXT WEEK...BUT
LONGER RANGE MODELS ARE IN BETTER AGREEMENT RIGHT NOW FOR THE
THANKSGIVING PERIOD...WITH A MILDER AND DRIER STRETCH OF WEATHER
LOOKING MORE LIKELY. WILL GO WITH MILDER TEMPERATURES THURSDAY AND
FRIDAY...ESPECIALLY OVER WESTERN PORTIONS OF THE CWA. IF LATEST
TRENDS PERSIST...TEMPERATURES WILL BE NEAR OR ABOVE AVERAGE IN MOST
AREAS.

&&

.AVIATION...FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING
ISSUED AT 251 PM MST FRI NOV 21 2014

VFR CONDITIONS ARE EXPECTED THROUGH EARLY SATURDAY.
BREEZY SOUTHWESTERLY WINDS WILL DEVELOP ACROSS NORTHEAST WY
OVERNIGHT.

&&

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

$$

SHORT TERM...JC
LONG TERM...26
AVIATION...26





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