Area Forecast Discussion
Issued by NWS Rapid City, SD

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000
FXUS63 KUNR 271059
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
459 AM MDT MON JUL 27 2015

.SHORT TERM...TODAY THROUGH TUESDAY NIGHT
ISSUED AT 207 AM MDT MON JUL 27 2015

THE LATEST WATER VAPOR IMAGES SHOWED AN INTENSE MIDLEVEL TROUGH
DEEPENING OVER THE PACIFIC NORTHWEST...WITH A RIDGE ANCHORED OVER
THE CNTRL/SRN PLAINS. AN MCS WAS JUST EAST OF THE CWA AND WAS
BEING AIDED BY A SHORT-WAVE TROUGH EMBEDDED IN THE UPPER FLOW. AT
THE SURFACE A LOW WAS OVER CNTRL WY WITH AN EXTENSION TO THE
NORTHEAST ACROSS ERN MT. THE MCS TO OUR NORTHEAST HAS TRIGGERED
GRAVITY WAVES PER THE KUDX WSR-88D AND THESE WERE PROPAGATING TO
THE SOUTHWEST TOWARD THE BLKHLS...HELPING TO MAINTAIN A MOIST
EASTERLY BOUNDARY LAYER FLOW.

FOR TODAY AND TNGT THE UPPER LOW WILL MOVE TO ERN MT WITH A POTENT
SHORT-WAVE TROUGH (-3SD H5 ANOMALIES) EJECTING ACROSS THE CWA.
STRONG FORCING FOR ASCENT COMBINED WITH AMPLE SHEAR AND BUOYANCY
WILL LEAD TO SCT SEVERE TSTORMS DEVELOPING ALONG A LEE TROUGH/
DRYLINE EARLY THIS AFTN OVER NERN WY AND THEN PROGRESSING ACROSS
WRN SD LATE THIS AFTN AND EVNG. A LOW-LEVEL THERMAL RIDGE (+3SD
850MB T ANOMALIES) ALSO WILL RESULT IN HOT WEATHER AGAIN TODAY...
AHEAD OF AN APPROACHING COLD FRONT THAT WILL BLAST THROUGH THE
AREA TNGT. THIS WILL PRODUCE CRITICAL FIRE WEATHER CONDITIONS
ACROSS NERN WY...SEE FIRE WX DISC BELOW. TSTORMS SHOULD BE OUT OF
THE CWA BY 09Z.

THE UPPER LOW WILL MOVE ACROSS NRN ND TUESDAY AND THEN NORTH OF MN
BY WEDS MRNG. THIS WILL PLACE THE CWA UNDER STRONG SUBSIDENCE AND
COLD ADVECTION FOR TUES...LEADING TO RATHER WINDY CONDITIONS ACROSS
THE NRN 2/3 OF THE AREA. BASED ON THE STANDARDIZED ANOMALIES OF 5
TO 7 FOR WESTERLY 850-MB WINDS ACROSS NWRN SD...WILL ISSUE A HIGH
WIND WATCH FOR TUES FOR THE PLAINS OF NWRN SD. WINDS WILL STILL BE
GUSTY TUES NGT BUT OVERALL SHOULD BE DIMINISHING. OTHERWISE...SOME
WRAP-AROUND SHOWERS MAY GET CLOSE TO NWRN SD TUES...BUT EXPECT
THEM TO STAY NORTH GIVEN THE AFOREMENTIONED SUBSIDENCE.

.LONG TERM...WEDNESDAY THROUGH SUNDAY
ISSUED AT 207 AM MDT MON JUL 27 2015

REGION WILL REMAIN UNDER NORTHWEST FLOW FOR THE REST OF THE WEEK
AS UPPER RIDGE BUILDS OVER THE WESTERN CONUS...RESULTING IN MAINLY
DRY WEATHER AND A GRADUAL WARMING TREND. A FEW WEAK DISTURBANCES
MAY RESULT IN SOME ISOLATED SHOWERS AND STORMS OVER THE SOUTHERN
CWA THURSDAY AND SATURDAY...BUT CHANCES ARE SLIGHT. HIGHS WILL BE
NEAR TO SLIGHTLY ABOVE SEASONAL AVERAGES FOR THIS TIME OF YEAR.

&&

.AVIATION...FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING
ISSUED AT 458 AM MDT MON JUL 27 2015

VFR CONDITIONS WILL PREVAIL INTO THIS AFTERNOON...WITH
BREEZY SOUTHERLY WINDS. A STRONG UPPER LEVEL TROUGH WILL PUSH INTO
THE REGION THIS AFTERNOON...WITH TS EXPECTED OVER PORTIONS OF THE
AREA BY MID/LATE AFTERNOON. MVFR CONDS WILL BE POSSIBLE WITH TS AS
WELL AS LARGE HAIL AND GUSTY WINDS. A STRONG COLD FRONT WILL PUSH
THROUGH THE REGION TONIGHT WITH GUSTY NW WINDS DEVELOPING BEHIND THE
FRONT.

&&

.FIRE WEATHER...
ISSUED AT 207 AM MDT MON JUL 27 2015

A DEEP UPPER LOW WILL MOVE ACROSS MT/ND TNGT AND TUES. AHEAD OF
THE LOW...VERY WARM SOUTHERLY FLOW WILL BRING DRIER AIR INTO NERN
WY. THE GUSTY SOUTH WINDS...HIGH TEMPERATURES...AND LOW HUMIDITIES
WILL LEAD TO RED FLAG CONDITIONS THIS AFTN/EVNG. ISOLD-SCT TSRA
ALSO WILL DEVELOP FROM 18-21Z...AND COULD RESULT IN DRY LIGHTNING
BEFORE THEY MOVE INTO WRN SD. FROM 21-03Z...A COLD FRONT WILL
SWEEP ACROSS NERN WY AND BRING GUSTY NORTHWEST WINDS. BECAUSE OF
THE RECENT DRYING OF FUELS...THESE WEATHER CONDITIONS WILL CREATE
CRITICAL FIRE WEATHER CONDITIONS OVER NERN WY.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...     HIGH WIND WATCH FROM TUESDAY MORNING THROUGH TUESDAY EVENING FOR
     SDZ001-002-012>014-073.

WY...RED FLAG WARNING FROM NOON TODAY TO MIDNIGHT MDT TONIGHT FOR
     WYZ259-297-298.

&&

$$

SHORT TERM...BUNKERS
LONG TERM...POJORLIE
AVIATION...POJORLIE
FIRE WEATHER...BUNKERS



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