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000
FXUS63 KUNR 010334
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
934 PM MDT THU JUL 31 2014

.UPDATE...
ISSUED AT 931 PM MDT THU JUL 31 2014

A SMALL CLUSTER OF TSTMS JUST EAST OF RAPID CITY CONTINUES TO PUSH
SEWD...WITH RADAR TRENDS SUGGESTING A DECREASE IN THIS ACTIVITY.
ONLY CHANGE TO FCST WAS TO ADD SMALL POPS INTO PARTS OF SWRN SD TO
ACCOUNT FOR THIS ACTIVITY.

&&

.SHORT TERM...THIS EVENING THROUGH FRIDAY NIGHT
ISSUED AT 216 PM MDT THU JUL 31 2014

A RIDGE WILL MOVE OVER THE WESTERN CONUS THROUGH SATURDAY. WEAK
SHORT-WAVE TROUGHS/SUBTLE DISTURBANCES WILL ROTATE AROUND THIS
RIDGE AND MOVE SOUTHEAST ACROSS THE FORECAST AREA. FORCING FOR
UPWARD/DOWNWARD MOTION WILL BE WEAK...AND MOISTURE AND INSTABILITY
WILL BE MARGINAL. THICKNESSES WILL BE STEADY TO SLOWLY RISING
THROUGH THE SHORT TERM. AS A RESULT...ONLY SMALL CHANCES OF
THUNDERSTORMS ARE EXPECTED...ALONG WITH TEMPERATURES NEAR AVERAGE.

FOR THIS AFTERNOON/EVENING...MLCAPE OF NEAR 500 J/KG AND LIMITED
FORCING FOR UPWARD MOTION WILL BRING A FEW THUNDERSTORMS TO THE
BLACK HILLS AND PARTS OF WESTERN SD. ANYTHING THAT DOES DEVELOP
SHOULD DIMINISH EARLY IN THE EVENING...AND WEAK CAPE/SHEAR
INDICATES SEVERE WEATHER WILL NOT OCCUR.

LATER TONIGHT..A SUBTLE SHORT-WAVE TROUGH MOVES TOWARD THE CWA WITH
WEAK Q-VECTOR CONVERGENCE BY 12Z OVER THE WRN CWA. LOW-LEVEL WARM
ADVECTION WILL BE FOCUSED OVER NWRN SD AS A SURFACE LOW MOVES TO
NEAR FAR NWRN SD. WITH MUCAPE AROUND 250 J/KG...MAY SEE DEVELOPMENT
OF THUNDERSTORMS LATE OVER THE NORTHEASTERN CWA.

ON FRIDAY...WEAK Q-VECTOR CONVERGENCE IS PROGGED AS THE SHORT-WAVE
TROUGH PROGRESSES ACROSS THE CWA. MOISTURE AND INSTABILITY WILL
INCREASE RELATIVE TO TODAY...AND THUS THERE WILL BE A SOMEWHAT
BETTER AND MORE WIDESPREAD CHANCE OF THUNDERSTORMS...ESPECIALLY IN
THE AFTERNOON. HOWEVER...CAPE AND DEEP-LAYER SHEAR WILL CONTINUE TO
BE RELATIVELY WEAK AND THUS DO NOT EXPECT ORGANIZED SEVERE WEATHER.

ON FRIDAY NIGHT...THE SHORT-WAVE TROUGH WILL SLOWLY EXIT THE
CWA...BUT THUNDERSTORMS WILL LINGER THROUGH THE EVENING...ESPECIALLY
IN PARTS OF SOUTH-CENTRAL SOUTH DAKOTA WHERE A SURFACE LOW WILL BE
PRESENT. OTHERWISE...CLEARING SKIES WILL WORK INTO NORTHWESTERN
AREAS.

&&

.LONG TERM...SATURDAY THROUGH THURSDAY
ISSUED AT 216 PM MDT THU JUL 31 2014

UPPER LEVEL RIDGE REMAINS ACROSS THE WESTERN CONUS THROUGH THE
WEEKEND. WITH LACK OF FORCING...MINIMAL THUNDERSTORM ACTIVITY
EXPECTED SATURDAY/SUNDAY. TEMPERATURES WILL BE NEAR AVERAGE FOR
THE WEEKEND. MODELS IN DECENT AGREEMENT WITH RIDGE BREAKING DOWN
MONDAY/TUESDAY...WITH MID LEVEL MOISTURE PLUME AND EMBEDDED
TROF/WEAK CLOSED LOW LIFTING NORTHEASTWARD THROUGH THE GREAT BASIN
INTO THE NORTHERN PLAINS. THIS WILL BRING AN INCREASE IN
THUNDERSTORM ACTIVITY AND SLIGHTLY COOLER TEMPERATURES.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 931 PM MDT THU JUL 31 2014

MAINLY VFR CONDITIONS WILL PREVAIL THROUGH THE FORECAST PERIOD.
ISOLATED -TSRA ARE POSSIBLE TONIGHT...WITH LOCAL MVFR VSBY. A
SLIGHTLY BETTER CHANCE OF -TSRA EXPECTED FRI AFTN...WITH LOCAL
MVFR VSBY.

&&

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

$$

UPDATE...JOHNSON
SHORT TERM...BUNKERS
LONG TERM...7
AVIATION...JOHNSON