Area Forecast Discussion
Issued by NWS Rapid City, SD

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000
FXUS63 KUNR 261746
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
1146 AM MDT SAT JUL 26 2014

.UPDATE...
ISSUED AT 744 AM MDT SAT JUL 26 2014

STRONG COMPACT UPPER LEVEL VORT MAX WILL CONTINUE TO SHIFT SE
ACROSS THE NORTHERN PLAINS. THE SOUTHERN FRINGE AND ASSOCIATED
STRONG LL MOMENTUM FIELDS WILL GRAZE THE NW SD PLAINS THIS
AFTERNOON...TIMING WITH PEAK DIURNAL MIXING. HAVE UPDATED WINDS
THERE AND ISSUED A WIND ADV FOR MUCH OF THE NW SD PLAINS.

&&

.SHORT TERM...TODAY THROUGH SUNDAY NIGHT
ISSUED AT 233 AM MDT SAT JUL 26 2014

WEAK SHORTWAVE TROF IS ZIPPING ALONG ZONAL FLOW...AND WILL MOVE
INTO EASTERN SD THIS MORNING. SURFACE LOW IS OVER SOUTH CENTRAL SD
W/ TROF NORTHWARD ALONG MISSOURI RIVER. THUNDERSTORMS DEVELOPED
AHEAD OF TROF EARLIER THIS EVENING...BUT HAVE MOVED INTO EAST
RIVER. ALTHOUGH MODELS CONTINUE TO KEEP A THETA-E RIDGE EXTENDING
INTO SOUTH CENTRAL SD...WILL LOWER POPS OVER THAT AREA FOR THE
MORNING. STRATUS AND FOG ARE DEVELOPING AHEAD OF TROF...BUT WOULD
BE BRIEF AS DEWPOINTS ARE MUCH LOWER BEHIND IT. AS DEEP UPPER LOW
DROPS SOUTHEASTWARD FROM SOUTHERN SASK TOWARD THE GREAT LAKES...
AND UPPER RIDGE BUILDS OVER THE ROCKIES...UPPER LEVEL PATTERN OVER
FORECAST AREA TRANSITIONS FROM CYCLONIC TO ANTICYCLONIC FLOW...
SHIFTING WEAK VORTICITY EASTWARD AND BRINGING DRIER AIR. SURFACE
RIDGE PUSHES INTO NORTHERN HIGH PLAINS WITH GUSTY WEST-NORTHWEST
WINDS OVER NORTHWESTERN SD TODAY. WINDS WILL APPROACH ADVISORY
CRITERIA WITH CAA...GOOD MIXING WITH DAYTIME HEATING...AND
FORECAST SOUNDINGS HAVE MOMENTUM TRANSFER NEAR 40KT. TEMPERATURES
WILL ALSO BE COOLER THRU SUNDAY AS SURFACE RIDGE EXTENDS OVER
PLAINS...AND WINDS SWITCH FROM NW TO NE.

&&

.LONG TERM...MONDAY THROUGH FRIDAY
ISSUED AT 233 AM MDT SAT JUL 26 2014

UPPER RIDGING WILL REMAIN OVER THE WESTERN CONUS THROUGH THE 3 TO 7
DAY PERIOD. THE MAIN AXIS IS FORECAST TO REMAINING ALONG AND WEST OF
THE CONTDVD. NW FLOW ALOFT IS EXPECTED WITH A FEW WEAK WAVES
CROSSING THROUGH...MAINLY TUESDAY THROUGH EARLY WEDNESDAY. THIS WILL
WARRANT A SLIGHT CHANCE OF STORMS PERIODICALLY...MAINLY TUESDAY AND
WEDNESDAY...BUT OVERALL A DRY EXTENDED PERIOD IS EXPECTED.
TEMPERATURES WILL BE A LITTLE BELOW SEASONAL AVERAGES.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY)
ISSUED AT 1145 AM MDT SAT JUL 26 2014

MVFR CIGS OVER SCNTRL SD WILL CONTINUE TO DISSIPATE OVER THE NEXT
HOUR OR TWO. OTHERWISE VFR CONDITIONS ARE EXPECTED THROUGH THE
FORECAST PERIOD.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...WIND ADVISORY UNTIL 6 PM MDT THIS EVENING FOR SDZ001-002-012>014.

WY...NONE.
&&

$$

UPDATE...JC
SHORT TERM...55
LONG TERM...CARPENTER
AVIATION...13





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