Area Forecast Discussion
Issued by NWS Rapid City, SD

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000
FXUS63 KUNR 300413
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
1013 PM MDT TUE JUL 29 2014

.UPDATE...
ISSUED AT 631 PM MDT TUE JUL 29 2014

LATEST RADAR/VISIBLE LOOPS SHOWED ISOLATED -TSRA DROPPING INTO
CENTRAL SD AHEAD OF A WEAK SHORTWAVE SEEN ON WATER VAPOUR OVER
CENTRAL ND. REGION ALSO UNDER THE TAIL END OF 70KT JET STREAK.
FORECAST UPDATED TO BRING LOW POPS FOR THOSE AREAS. SHOULD NOT
MAKE IT TOO FAR INTO CWA GIVEN 00Z KUNR SOUNDING.

&&

.SHORT TERM...THIS EVENING THROUGH WEDNESDAY NIGHT
ISSUED AT 209 PM MDT TUE JUL 29 2014

WESTERN NOAM RIDGE AND GREAT LAKES TROUGH WILL REMAIN IN PLACE
THROUGH THE PERIOD. LONG FETCH SOUTHERLY FLOW ON THE WEST SIDE OF
THE RIDGE WILL CONTINUE TO SUPPORT MONSOON FLOW WITH MID-HIGH
LEVEL MOISTURE AND EMBEDDED IMPULSES ROTATING AROUND THE RIDGE
PERIPHERY. ONE SUCH IMPULSE IS IN THE PROCESS OF SLOWLY EXITING
THE FAR SW FA...WITH SHRA CHANCES WANING THROUGH EVENING.
MEANWHILE...COMPACT WEAK VORT LOBES ARE EVIDENT ON THE WESTERN
EDGE OF THE EASTERN NOAM TROUGH...ONE CURRENTLY SUPPORTING SCT
SHRA/TS OVER NORTHERN ND. THESE FEATURES WILL SLOWLY MIGRATE SOUTH
INTO THE CENTRAL DAKOTAS...SUPPORTING A WEAK LL PRESSURE RESPONSE
AND INCREASED CONDITIONAL INSTABILITY IN THEIR VICINITY.

TONIGHT...MID LEVEL IMPULSE WILL CONTINUE TO ADVECT SOUTH AWAY FROM
THE WESTERN FA. SOME LINGERING SHRA ACTIVITY WILL BE POSSIBLE
THROUGH EARLY EVENING THERE...WITH DRY CONDITIONS EXPECTED THE
REMAINDER OF THE NIGHT. CLEARING SKIES AND LIGHT WINDS WILL SUPPORT
DECENT RADIATIONAL COOLING...WITH LOWS IN THE 50S AND SOME 40S
EXPECTED.

WEDNESDAY...AFOREMENTIONED WEAK VORT LOBES WILL ADVECT INTO CENTRAL
SD WITH AN ASSOCIATED COLD POCKET ALOFT. MODEL MOMENTUM AND
PRESSURE FIELDS INDICATE A WEAK LL RESPONSE WITH ENSUING CONVERGENCE
OVER THE SE FA. THIS COUPLED WITH DIURNAL HEATING MAY BE ENOUGH TO
SUPPORT A FEW SHRA/TS OVER THE FAR SE...A SIGNAL THAT HAS BEEN
HINTED AT IN THE HIRES MODELS FOR THE LAST SEVERAL RUNS. HAVE DECIDE
TO ADD A SMALL POP SCENTRAL IN THE AFTERNOON. A FEW MODEL SOLUTIONS
INDICATE THE POTENTIAL FOR CONVECTION LATE WED MORNING...BUT OPTED
FOR A MENTION CLOSER TO PEAK HEATING. LINGERING MOISTURE WITH MID
RIDGE CONVERGENCE MAY ALSO SUPPORT AN ISOLD SHRA OVER THE CENTRAL
ANS SOUTHERN BLACK HILLS. HOWEVER...LACK OF UPPER LEVEL SUPPORT
PRECLUDES A POP/WX MENTION THERE. BUMPED TEMPS UP IN THE EAST GIVEN
ONGOING DRY CONDITIONS...ESP AROUND THE PHP-ICR AREA. A FEW
LINGERING SHRA ARE POSSIBLE OVER SCNTRL AREAS INTO THE EVENING IF
ACTIVITY DOES DEVELOP WED AFTERNOON. OTHERWISE...DRY CONDITIONS
EXPECTED WED NIGHT ATTM.

&&

.LONG TERM...THURSDAY THROUGH TUESDAY
ISSUED AT 209 PM MDT TUE JUL 29 2014

UPPER LEVEL RIDGING OVER THE WESTERN CONUS WILL CONTINUE THROUGH END
OF THE WEEK INTO THE WEEKEND. GENERALLY DRY WEATHER IS EXPECTED
THROUGH THIS WEEKEND...BUT MODELS ARE INDICATING A SLOW TRANSITION
TO A MORE ACTIVE PATTERN NEXT WEEK. A SERIES OF WAVES MAY PUSH
THROUGH THE FLOW SLOWLY...BREAKING DOWN THE RIDGE...AND BRINGING
BETTER CHANCES FOR STORMS. TEMPERATURES OVERALL WILL NEAR SEASONAL
AVERAGES THROUGH THE END OF THE WEEK...THEN A SLIGHT WARMING TREND
IS POSSIBLE EARLY NEXT WEEK.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1011 PM MDT TUE JUL 29 2014

VFR CONDITIONS WILL PREVAIL THROUGH THE PERIOD AS MID/HIGH CLOUDS
PASS OVERHEAD. ISOLATED -TSRA MAY DEVELOP WEDNESDAY AFTERNOON OVER
SOUTH CENTRAL SD WITH LOCAL MVFR CIGS IN THE HEAVIEST SHOWERS.

&&

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

$$

UPDATE...HELGESON
SHORT TERM...JC
LONG TERM...13
AVIATION...HELGESON



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