Area Forecast Discussion
Issued by NWS Rapid City, SD

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000
FXUS63 KUNR 262325
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
525 PM MDT SUN JUL 26 2015

.SHORT TERM...THIS EVENING THROUGH MONDAY NIGHT
ISSUED AT 221 PM MDT SUN JUL 26 2015

WATER VAPOR SHOWS LARGE UPPER LOW PUSHING INTO THE PAC NW...WITH
LEAD SHORT WAVE EMBEDDED IN SW FLOW EJECTING OUT OF THE CNTRL
ROCKIES. AT THE SFC...LOW IS LOCATED ALONG THE MT/ND BORDER WITH
TROF EXTENDING SWD THROUGH THE NEB PANHANDLE...AND VIS/RADAR
IMAGERY SHOWS DEVELOPING CU/SCT TSTMS ALONG THE TROF OVER THE NEB
PANHANDLE.

THIS AFTN/TONIGHT...NARROW CORRIDOR OF MLCAPE OF 2500-3500J/KG EXITS
FROM THE ERN SLOPES OF THE BLKHLS INTO THE NEB PANHANDLE...ALONG THE
SFC TROF...WHERE CU/SCT TSTMS ARE DEVELOPING. EXPECT ADDITIONAL
DEVELOPMENT ALONG THIS BOUNDARY...AS INDICATED BY MOST CAMS...WITH
AFORMENTIONED SHORT WAVE EJECTING OUT OF THE CNTRL ROCKIES. WITH
EFFECTIVE BULK SHEAR OF 35-45KTS AND DCAPE AROUND 1800J/KG...A FEW
SVR STORMS POSSIBLE WITH A LARGE HAIL/DAMAGING WIND THREAT.
ADDITIONAL STORMS MAY FIRE OVER THE BLKHLS AND MOVE INTO THE PLAINS.
MOST ACTIVITY SHOULD DISSIPATE/EXIT THE CWFA BEFORE SUNSET THIS EVE.

MONDAY...UPPER LOW WILL SHIFT QUICKLY EWD INTO WRN MT BY LATE AFTN.
SFC TROF WILL DEEPEN OVER ERN WY/ERN MT...WITH A DEEPLY MIXED AMS
DEVELOPING ALONG THE TROF AND PLUMMETING DEWPOINTS. GUSTY SW WINDS
WILL DEVELOP WITH RH`S DIPPING WELL INTO THE TEENS ACRS NERN WY FOR
A HEIGHTENED FIRE WX THREAT...SEE FIRE WX DISCUSSION BELOW. MOISTURE
AND INSTABILITY WILL BE SUFFICIENT OVER WRN SD FOR ISOLD-SCT TSRA TO
DEVELOP IN THE AFTN ALONG THE SFC TROF. SHEAR SUFFICIENT FOR
ROTATING UPDRAFTS/SVR STORMS ACRS WRN SD...PUSHING INTO CNTRL SD
LATE IN THE AFTN/EARLY EVE. CDFNT WILL THEN BLAST THROUGH THE CWFA
MONDAY AFTN PRODUCING GUSTY NW WINDS...AND A WIND ADVISORY MAY
BECOME NECESSARY.

.LONG TERM...TUESDAY THROUGH SUNDAY
ISSUED AT 221 PM MDT SUN JUL 26 2015

DEEP CLOSED UPPER LOW WILL CONTINUE MOVING ALONG THE
CANADIAN/ND BORDER TUESDAY...WITH MUCH COOLER AND DRIER AIR ACROSS
THE REGION. MODELS CONTINUE TO SHOW STRONGER WINDS DURING THE DAY
TUESDAY...ESPECIALLY ACROSS NW SD WHERE ADVISORY CRITERIA WINDS WILL
BE POSSIBLE. HIGHS TUESDAY WILL RANGE FROM THE MID 70S TO MID 80S.
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.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING)
ISSUED AT 522 PM MDT SUN JUL 26 2015

THUNDERSTORMS WILL LINGER OVER FAR NW SD AND SCENTRAL SD THROUGH
EVENING. OTHERWISE VFR CONDITIONS WILL PREVAIL THROUGH THE
FORECAST PERIOD. A STRONG UPPER LEVEL TROUGH WILL PUSH INTO THE
REGION MONDAY AFTERNOON...WITH TS EXPECTED OVER PORTIONS OF
WESTERN SD BY LATE IN THE AFTERNOON. MVFR CONDS WILL BE POSSIBLE
WITH TS.

&&

.FIRE WEATHER...
ISSUED AT 221 PM MDT SUN JUL 26 2015

A DEEP UPPER LOW WILL MOVE ACROSS MT MONDAY AND TUESDAY. 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 MONDAY AFTN/EVNG.
ISOLD TSRA ALSO MAY DEVELOP MONDAY AFTN...AND COULD RESULT IN DRY
LIGHTNING. ON MONDAY EVNG A COLD FRONT WILL SWEEP ACROSS NERN WY
AND BRING GUSTY NORTHWEST WINDS. WITH INCREASINGLY DRY FUELS...THE
NORTHEAST WYOMING PLAINS WILL SEE CRITICAL FIRE WEATHER CONDITIONS
MONDAY AFTN/EVNG.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...WY...RED FLAG WARNING FROM NOON MONDAY TO MIDNIGHT MDT MONDAY NIGHT
     FOR WYZ259-297-298.

&&

$$

SHORT TERM...JOHNSON
LONG TERM...13
AVIATION...JC
FIRE WEATHER...13


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