Area Forecast Discussion
Issued by NWS Rapid City, SD

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FXUS63 KUNR 052107
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
206 PM MST FRI FEB 5 2016

.SHORT TERM...THIS EVENING THROUGH SUNDAY NIGHT
ISSUED AT 205 PM MST FRI FEB 5 2016

POTENT MID LEVEL IMPULSE IN THE PAC NW WILL QUICKLY ADVECT EAST
ACROSS THE NORTHERN PLAINS THIS WEEKEND...SUPPORTING MILD CONDS
SAT...AND COOLER BUT VERY WINDY CONDS SUNDAY. BIGGEST CONCERN WITH
THIS SYSTEM WILL BE STRONG NW WINDS...WITH A VERY GOOD SETUP FOR
WIDESPREAD 50-70 MPH WINDS ACROSS NW SD SUN.

TONIGHT...WAA WILL SPREAD OVER THE REGION WITH STRONG SFC
PRESSURE FALLS ENSUING. THIS WILL SUPPORT INCREASING SW WINDS OVER
NE WY AND IN THE FAVORED NORTHERN BH DOWNSLOPE AREAS...WITH WINDS
OF 20-30 AND GUSTS IN THE 40S EXPECTED THERE LATER TONIGHT. WAA
/POS-THETA-E WILL EVENTUALLY SUPPORT A BAND OF MID CLOUD/VIRGA
OVER THE AREA TOWARD DAWN OVER WESTERN AREAS.

SAT/SUN...POS THETA-E BAND WILL SHIFT QUICKLY EAST ACROSS THE
AREA...WITH AT MOST A FEW SPRINKLES/FLURRIES POSSIBLE...CERTAINLY
NOT ENOUGH TO MENTION IN THE FORECAST. OTHERWISE...SFC COLD FRONT
WILL ENTER THE AREA BY AFTERNOON...WITH SFC PRESSURE RISES AND CAA
ADV ENSUING ACROSS THE NW. LINKED WIND PROFILES/MODERATE
MIXING/AND ISALLOBARIC ALIGNMENT WITH THE LL FLOW WILL SUPPORT
GOOD TRANSLATION OF STRONGER FLOW TO THE SFC. IN
ADDITION...GEOSTROPHIC WINDS AT H925 INDICATE 70+ KNOTS ACROSS NW
SD...WHICH SHOULD SUPPORT SFC GUSTS IN EXCESS OF 60 KNOTS.
HENCE...HAVE DECIDED TO ISSUE A HIGH WIND WARNING ACROSS FAR NW SD
STARTING SAT AFTERNOON. STRONGER FLOW IS NOT EXPECTED OVER THE
SOUTHERN HALF OF THE AREA UNTIL SUNDAY MORNING AND WILL LET THE
WATCH RIDE AS THIS SYSTEM IS FORECAST TO COME IN ABOUT 6 HOURS
EARLIER...LEADING TO A SHIFT IN MAX WINDS ALOFT MORE TOWARD SUN
MORNING AS APPOSED TO SUN AFTERNOON. BUFFER PROFILES INDICATE THE
POTENTIAL FOR 60-70 MPH GUST AT ALL PLACE IN THE WATCH/WARNING
OUTSIDE OF THE BLACK HILLS...WHICH SEEMS VERY REASONABLE GIVEN
MIXING POTENTIALS. ALSO EXTENDED THE WATCH TO THE BLACK HILLS AS
CONCERNS OVER TREE FALLS PER PINE BEETLE KILLS. WINDS OF 40-60 MPH
WILL BE POSSIBLE IN PARTS OF THE HILLS...ESP ON RIDGES.

RETAINED A LOW CHANCE FOR SOME LIGHT RAIN OR SNOW ACROSS THE
NORTHERN BH AND NORTHWEST SD SAT EVENING...ALTHOUGH DRIER PROFILES
CERTAINLY DON/T WARRANT MORE THAN SLIGHT CHANCE POPS ATTM. A WEAK
UPSLOPE SIGNAL IS PRESENT IN THE NORTHERN BLACK HILLS...HOWEVER
LACK OF APPRECIABLE MOISTURE WILL HIGHLY LIMIT ANY ACTIVITY.

AS FOR TEMPS...EXPECT VERY MILD CONDS SAT WITH SOME 50S EXPECTED
ON THE SD PLAINS...POSSIBLY EVEN A 60 OR TWO DEPENDING ON CLOUD
COVER. COOLER CONDS ARE EXPECTED SUN...WITH MOSTLY 30S AND A FEW
40S.

.LONG TERM...MONDAY THROUGH FRIDAY
ISSUED AT 205 PM MST FRI FEB 5 2016

A LARGE SCALE RIDGE BUILDS OVER THE WESTERN CONUS ON
MONDAY AND TUESDAY...BEFORE SHIFTING EAST AND BREAKING DOWN BY
MIDWEEK. A WEAK WAVE PASSES THROUGH THE FLOW THURSDAY AND THEN THE
UPPER FLOW BECOMES MORE ZONAL FOR NEXT WEEKEND. TEMPERATURES WILL
REMAIN COOL ON MONDAY BUT WILL WARM QUITE A BIT FOR TUESDAY AND
WEDNESDAY. THERE WILL BE A SLIGHT COOL DOWN ON THURSDAY...BEFORE
REBOUNDING FOR THE END OF THE WEEK. OVERALL TEMPERATURES WILL BE
ABOVE AVERAGE FOR THE ENTIRE EXTENDED FORECAST PERIOD.

&&

.AVIATION...FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING
ISSUED AT 205 PM MST FRI FEB 5 2016

VFR CONDITIONS EXPECTED THROUGH THE PERIOD. WINDS WILL
INCREASE THROUGH THE DAY ON SATURDAY...WITH VERY STRONG WEST TO
NORTHWEST WINDS BEGINNING AROUND MIDDAY...ESPECIALLY ACROSS THE
NORTHWESTERN SOUTH DAKOTA PLAINS.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...HIGH WIND WATCH FROM LATE SATURDAY NIGHT THROUGH SUNDAY EVENING
     FOR SDZ014-024>026-028>032-043-044-046-047-049-072>074.

     HIGH WIND WARNING FROM 2 PM SATURDAY TO 8 PM MST SUNDAY FOR
     SDZ001-002-012-013.

WY...HIGH WIND WATCH FROM LATE SATURDAY NIGHT THROUGH SUNDAY EVENING
     FOR WYZ057-071.

&&

$$

SHORT TERM...JC
LONG TERM...MLS
AVIATION...MLS


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