Area Forecast Discussion
Issued by NWS Rapid City, SD

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000
FXUS63 KUNR 282132
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
332 PM MDT THU AUG 28 2014

.SHORT TERM...THIS EVENING THROUGH FRIDAY NIGHT
ISSUED AT 330 PM MDT THU AUG 28 2014

CURRENT SURFACE ANALYSIS SHOWS LOW PRESSURE OVER CENTRAL
NEB...WITH INVERTED TROF STRETCHING NORTHWARD ACROSS CENTRAL SD.
HIGH PRESSURE IS IN PLACE OVER THE CENTRAL ROCKIES. UPPER LEVEL
ANALYSIS SHOWS LOW NOW OVER FAR NORTHEAST CO...SLOWLY MOVING EAST-
SOUTHEAST. KUDX RADAR SHOWS ISOLATED TO SCATTERED SHOWERS FROM
CENTRAL SD TO FAR SOUTHWEST SD. THERE ARE A FEW LIGHTNING STRIKES
FROM TIME TO TIME WITH THE ACTIVITY OVER SOUTHERN SD. SKIES RANGE
FROM MOSTLY SUNNY OVER NORTHEAST WY AND FAR NORTHWEST SD TO MOSTLY
CLOUDY SOUTH AND EAST OF THE BLACK HILLS. TEMPS ARE IN THE 70S AND
LOWER 80S WITH LIGHT NORTHERLY WINDS IN MOST AREAS.

CONDITIONS WILL CONTINUE TO GRADUALLY IMPROVE THROUGH THE EVENING
FOR AREAS SOUTH AND EAST OF THE BLACK HILLS...WITH MOSTLY CLEAR
SKIES OVER WESTERN AND NORTHERN AREAS. HAVE ADDED CHANCES FOR
SHOWERS AND STORMS ACROSS SOUTH CENTRAL SD FOR THE EVENING HOURS AS
SYSTEM IS SLOWER TO MOVE OUT THAN WAS EXPECTED. WITH LOW LEVEL
MOISTURE HANGING AROUND OVER EASTERN PORTIONS OF THE CWA...HAVE KEPT
PATCHY FOG IN FOR MOST OF THE SD PLAINS. LOWS TONIGHT WILL BE IN THE
50S AND LOWER 60S. WINDS WILL MOSTLY BE LIGHT AND VARIABLE.

THE NEXT UPPER LEVEL WAVE...MUCH WEAKER THAN THE CURRENT ONE...WILL
MOVE QUICKLY INTO THE AREA ON FRIDAY...WITH INCREASING CHANCES FOR
SHOWERS AND THUNDERSTORMS THROUGH THE DAY FROM WEST TO EAST. A WEAK
COLD FRONT WILL ALSO SLIDE SOUTH INTO THE AREA WITH THE SHORTWAVE.
THE THREAT FOR SEVERE STORMS WILL REMAIN VERY LOW...BUT SUFFICIENT
INSTABILITY IS EXPECTED TO THE EAST OF THE BLACK HILLS IN THE
AFTERNOON TO POSSIBLY GET A STRONG STORM OR TWO GOING. HIGHS WILL BE
IN THE 80S...WITH SOME 70S ACROSS THE BLACK HILLS AND FAR
NORTHWESTERN SD. NORTHWESTERLY WINDS WILL INCREASE BEHIND THE FRONT
DURING THE LATE MORNING AND AFTERNOON...A BIT BREEZY AT TIMES OVER
THE WESTERN SD PLAINS. LINGERING SHOWERS SHOULD TAPER OFF QUICKLY IN
THE EVENING AS THE WAVE PUSHES EAST OF THE AREA.

&&

.LONG TERM...SATURDAY THROUGH THURSDAY
ISSUED AT 330 PM MDT THU AUG 28 2014

SATURDAY...SHORTWAVE RIDGE OVER THE CWA WILL QUICKLY MOVE INTO THE
MIDWEST DURING THE DAY AS A SHORTWAVE TROUGH ZIPS THROUGH MT INTO
ND/WY BY SATURDAY EVENING. SURFACE CYCLONE WILL DEVELOP OVER EASTERN
MT AND MOVES INTO THE CENTRAL DAKOTAS SATURDAY NIGHT. LOW LEVEL
MOISTURE CONVERGENCE ALONG THE FRONT WILL RESULT IN A NARROW BAND OF
1-2KJ/KG MLCAPE FROM SOUTHEAST MT INTO CENTRAL SD. 15-20M/S 0-6KM
BULK SHEAR SPREADS ACROSS NORTHWEST SD DURING PEAK HEATING. MLCIN
SHOULD BE BROKEN BY SURFACE FORCING AND LIFT AHEAD OF SHORTWAVE
RESULTING IN STRONG/POTENTIALLY SEVERE THUNDERSTORMS LATER SATURDAY
AFTERNOON INTO THE EVENING HOURS. STORMS MAY CONGEAL INTO A SMALL
MCS GIVEN DEVELOPING 50KT LOW LEVEL JET ACROSS THE EASTERN DAKOTAS
SATURDAY NIGHT. TEMPERATURES WILL BE TRICKY WITH VERY WARM READINGS
AHEAD OF THE LOW AND COOLER READINGS BEHIND THE FRONT.

SUNDAY THROUGH TUESDAY...UPPER TROUGH WITH EMBEDDED SHORTWAVES
SAUNTERS ACROSS THE DAKOTAS/SOUTH CENTRAL CANADA BRINGING SHRA/TSRA
CHANCES...ALTHOUGH COVERAGE SHOULD BE LOWER THAN RECENT MEMORY GIVEN
DRIER NORTHWEST FLOW. TEMPERATURES WILL BE NOTICEABLY COOLER SUNDAY
AND THEN WARM SLIGHTLY THROUGH TUESDAY.

WEDNESDAY/THURSDAY...UPPER RIDGE SHOULD BUILD INTO THE NORTHERN
PLAINS AS UPPER TROUGH DEEPENS OVER THE NORTHWEST US. DRIER AND
WARMER PATTERN MAY EVOLVE GIVEN THERMAL RIDGE AMPLIFICATION.

&&

.AVIATION...FOR THE 00Z TAFS THROUGH 00Z FRIDAY EVENING
ISSUED AT 330 PM MDT THU AUG 28 2014

SCATTERED -SHRA/-TSRA ALONG/EAST OF A LINE FROM KMGB TO
KCDR WILL CONTINUE TO SLIDE EAST THIS AFTERNOON...EXITING THE AREA
COMPLETELY THIS EVENING. AREAS IFR CIGS/VSBYS ASSOCIATED WITH THE
PRECIPITATION AND ST/BR WILL SHIFT EAST ALSO. BEHIND THESE
FEATURES...VFR CONDITIONS ARE EXPECTED THROUGH FRIDAY MORNING. THE
EXCEPTION WILL BE ON THE SD PLAINS LATER TONIGHT WHERE LOCAL MVFR
VSBYS DUE TO BR MAY OCCUR.

&&

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

$$

SHORT TERM...26
LONG TERM...HELGESON
AVIATION...HELGESON





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