Area Forecast Discussion
Issued by NWS Rapid City, SD

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000
FXUS63 KUNR 282105
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
205 PM MST WED JAN 28 2015

.SHORT TERM...THIS EVENING THROUGH THURSDAY NIGHT
ISSUED AT 205 PM MST WED JAN 28 2015

PRIMARY UPPER LEVEL SHORTWAVE AND ASSOCIATED SFC
TROUGH CONTINUES TO ADVECT EAST ACROSS THE AREA THIS
AFTERNOON...WITH A TRAILING SECONDARY WAVE OVER EASTERN MT
ASSOCIATED WITH THE MAIN COLD FRONT. WEAK ASCENT COUPLED WITH A LL
MOISTURE RIDGE IS SUPPORTING A FEW SHRA OVER THE SW HALF OF THE
FA...WITH A WANING TREND IN COVERAGE EXPECTED INTO EARLY EVENING.
MAIN STORY IS THE WINDS ACROSS THE SD PLAINS. STRONG LL
FLOW/PRESSURE RISE COUPLET/AND CAA WILL COMBINE TO SUPPORT NEAR OR
AT WIND ADV WINDS THROUGH MUCH OF THE EVENING. DID EXTEND THE WIND
ADV TO COVER SCENTRAL SD...AND IN TIME THROUGH THE EVENING.
OTHERWISE...MAINLY BENIGN WEATHER IN THE PERIOD AS THE REGION
REMAINS ON THE WARM SIDE OF FAST NW FLOW ALOFT. WEAK SFC RIDGE WILL
ADVECT THROUGH THE AREA THUR...WITH A ANOTHER WEAK FAST MOVING
SYSTEM EXPECTED BY FRIDAY. MILD WEATHER WILL CONTINUE.

GUSTY NW WINDS WILL PERSIST ON THE SD PLAINS INTO THE EVENING.
SECONDARY PRESSURE RISE/CAA PUSH WILL WITH STEEP LL LAPS RATES WILL
SUPPORT GOOD MIXING OF FAST FLOW DOWN. THIS WILL ALLOW WINDS OF 25
TO 35 MPH WITH GUST TO 50 TO CONTINUE ON MUCH OF THE SD PLAINS
THROUGH MOST OF THE EVENING. WINDS WILL BEGIN TO WANE LATE THIS
EVENING INTO EARLY THUR MORNING. A POCKET OF CAA LOW CLOUDS WILL
PUSH INTO WESTERN SD THIS EVENING AND COVER MOST OF THE EASTERN FA
THUR MORNING. THE NAM IS CERTAINLY THE MOST AGGRESSIVE PER LOW
CLOUDS...KEEPING THEM IN PLACE OVER THE SD PLAINS THROUGH MUCH OF
THUR. HOWEVER...FEEL THIS IS A LITTLE OVERDONE GIVEN LACK OF
APPRECIABLE SNOW COVER...WHICH WILL SUPPORT BETTER MIXING AND
SUBSEQUENT MIX OUT OF CLOUDS THUR AFTERNOON. THUS...SIDED WITH THE
WARMER SIDE OF GUIDANCE FOR THUR PER HIGHS. WAA WILL DEVELOP THUR
AFTERNOON AND SPREAD WEST TO EAST ACROSS THE REGION. THIS SHOULD
KEEP TEMPS UP OVERNIGHT THUR IN THE FAVORED DOWNSLOPING AREAS AS
PRESSURE FALLS REV UP AND SW FLOW INCREASES.

.LONG TERM...FRIDAY THROUGH WEDNESDAY
ISSUED AT 205 PM MST WED JAN 28 2015

ONE MORE ABOVE AVERAGE DAY IS EXPECTED ON FRIDAY...WITH
HIGHS IN THE 40S TO AROUND 50 DEGREES. A COOL DOWN IS STILL IN STORE
FOR THIS WEEKEND AND EARLY NEXT WEEK...THOUGH GFS ENSEMBLE STILL
SHOWS A FAIRLY LARGE SPREAD OF POSSIBLE TEMPS THROUGH THE PERIOD.
NORTHWEST FLOW WILL BRING A CANADIAN COLD FRONT ACROSS THE AREA
EARLY ON SATURDAY. HIGH TEMPS WILL BE NEAR AVERAGE ON
SATURDAY...THEN GENERALLY NEAR TO BELOW AVERAGE FROM SUNDAY THROUGH
TUESDAY AS THE BAROCLINIC ZONE WAVERS BACK AND FORTH ACROSS THE
AREA. SHORTWAVE ENERGY BEHIND THE FRONT WILL BRING A CHANCE
FOR SNOW SATURDAY INTO SATURDAY NIGHT...NOW LOOKING A LITTLE LATER
THAN PREVIOUS RUNS. ANY ACCUMULATIONS LOOK TO BE LIGHT ACROSS THE
AREA. NORTHWEST FLOW ALOFT WILL CONTINUE TO BRING WEAK DISTURBANCES
ACROSS THE AREA THROUGH THE REST OF THE EXTENDED...WITH CONSIDERABLE
CLOUD COVER AND AT LEAST SOME LOW CHANCES FOR POPS ACROSS PORTIONS
OF THE AREA...MOSTLY FAR NORTHEAST WY...THE BLACK HILLS...AND FAR
NORTHWEST SD.

&&

.AVIATION...FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING
ISSUED AT 205 PM MST WED JAN 28 2015

GUSTY NORTHWEST WINDS OF 15 TO 30 KTS AND GUSTS TO 40 KTS WILL
DEVELOP THIS AFTERNOON BEHIND THE COLD FRONT...STRONGEST WINDS
OVER THE WESTERN SD PLAINS. THERE WILL ALSO BE A CHANCE FOR LIGHT
RAIN SHOWERS ACROSS NORTHEAST WY AND SOUTHWEST SD DURING THE DAY.
MODELS ARE SHOWING SOME MVFR CIGS THIS EVENING FOR BOTH KGCC AND
KRAP. ADDED MVFR CIGS TO KGCC TAF...BUT DO NOT AGREE WITH THE LOW
CIGS AT KRAP SO LEFT THEM OUT FOR NOW. OTHERWISE...MAINLY VFR
CONDITIONS ARE EXPECTED.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...WIND ADVISORY UNTIL 11 PM MST /MIDNIGHT CST/ THIS EVENING FOR
     SDZ001-002-012>014-025-026-031-032-043-044-046-047-049-072-
     073.

WY...NONE.
&&

$$

SHORT TERM...JC
LONG TERM...POJORLIE
AVIATION...POJORLIE






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