Area Forecast Discussion
Issued by NWS Rapid City, SD

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FXUS63 KUNR 261951
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
151 PM MDT FRI SEP 26 2014

.SHORT TERM...THIS EVENING THROUGH SATURDAY NIGHT
ISSUED AT 143 PM MDT FRI SEP 26 2014

WATER VAPOR SHOWS PERSISTENT UPPER RIDGE EXTENDING THROUGH THE NRN
PLAINS. AT THE SFC...WEAK TROF IS BEGINNING TO SLIDE INTO THE FAR
WRN DAKOTAS. CLEAR SKIES CONTINUE ACROSS THE CWFA THIS AFTN WITH
TEMPS IN THE 80S TO LOW 90S.

UPPER RIDGE WILL PERSIST THROUGH SATURDAY. TEMPS WILL BE COOLER
ACROSS THE WRN HALF OF THE CWFA AS COOLER AIR FILTERS IN BEHIND
THE SFC TROF. HOWEVER...THICKNESS RIDGE WILL KEEP TEMPS VERY WARM
ACROSS THE ERN HALF OF THE CWFA WITH HIGHS ONCE AGAIN NEAR 90.
UPPER RIDGE WILL BEGIN TO BREAK DOWN ACROSS THE FAR WRN CWFA LATE
SATURDAY NIGHT AS UPPER LOW MOVES INTO THE GREAT BASIN...WITH A
SLIGHT CHANCE OF TSTMS ACROSS OUR FAR WRN ZONES.

&&

.LONG TERM...SUNDAY THROUGH FRIDAY
ISSUED AT 143 PM MDT FRI SEP 26 2014

A CUTOFF UPPER LOW OVER NV AT 12Z SUN WILL MOVE SLOWLY
NORTHEAST ACROSS THE NRN PLAINS THROUGH WED...BEING SLOWED BY THE
STRONG CNTRL CONUS RIDGE. AS IT EJECTS NORTHEAST IT WILL OPEN UP AND
TAKE ON A NEGATIVE TILT. THE UPSTREAM KICKER...RESPONSIBLE FOR
EJECTING THIS LOW...WILL CROSS THE NRN PLAINS ON WED AND PHASE WITH
THIS LOW. NORTHWEST UPPER FLOW THEN WILL PREVAIL THROUGH THU...WITH
PERHAPS A SHORT-WAVE TROUGH CLIPPING NRN PARTS OF THE CWA. THERE-
AFTER THE MODELS SUGGEST RIDGING FRIDAY THROUGH NEXT WEEKEND.

THE RESULT OF THIS UPPER TROUGH WILL BE A COOL DOWN EARLY IN THE WEEK
WITH NEAR TO SLIGHTLY BELOW AVERAGE TEMPS THROUGH FRIDAY. THE BEST
CHANCE OF PRECIP WILL BE LATE SUN NIGHT THROUGH TUE MRNG. HOWEVER...
WITH THE CYCLONIC UPPER FLOW THERE SHOULD BE ISOLD/SCT SHOWERS OVER
THE AREA THROUGH AT LEAST WED...POSSIBLY THU. DECENT QPF AMOUNTS ARE
FORECAST BY THE MODELS ON MONDAY...SO COULD SEE A WIDESPREAD 0.25-
1.00 INCHES OF RAIN (TOO WARM FOR SNOW). THIS IS CONSISTENT WITH
FORECAST PWATS OF 150 PERCENT OF AVERAGE. MOREOVER...THETA-E RIDGE
NOSING INTO SCNTRL SD ON MONDAY WITH 750-1000 J/KG MLCAPE AND 35-45
KTS DEEP LAYER SHEAR MAY SUPPORT A FEW SEVERE STORMS.

ALTHOUGH A WARMING TREND MAY DEVELOP BY NEXT WEEKEND...THE RMOP
(RELATIVE MEASURE OF PREDICTABILITY) PRODUCT SUGGESTS MUCH UNCER-
TAINTY IN THE RIDGE ACTUALLY DEVELOPING FAR ENOUGH EASTWARD TO
PRODUCE THE WARMING.

&&

.AVIATION...FOR THE 18Z TAFS THROUGH 18Z SATURDAY
ISSUED AT 143 PM MDT FRI SEP 26 2014

VFR CONDITIONS ARE EXPECTED THROUGH THE PERIOD.

&&

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

$$

SHORT TERM...JOHNSON
LONG TERM...BUNKERS
AVIATION...BUNKERS





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