Area Forecast Discussion
Issued by NWS Rapid City, SD

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000
FXUS63 KUNR 201922
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
122 PM MDT MON OCT 20 2014

.SHORT TERM...THIS EVENING THROUGH TUESDAY NIGHT
ISSUED AT 121 PM MDT MON OCT 20 2014

AN UPPER RIDGE WAS DOMINATING OUR WEATHER TODAY PER WATER VAPOR
SATELLITE IMAGES...WHILE A LARGE-SCALE TROUGH WAS MOVING TOWARD
THE WRN CONUS. SKIES WERE CLEAR OVER THE CWA WITH TEMPS 10-15F
ABOVE AVERAGE. SFC PRESSURE FALLS AND A TIGHTENING MSLP GRADIENT
WAS SUPPORTING SLY WINDS OF 10-20 MPH ACROSS MUCH OF THE PLAINS.

FOR TNGT THE MILD AND DRY WEATHER WILL CONTINUE AS THE UPPER RIDGE
MOVES OVER THE ERN DAKOTAS AND A LOW-LEVEL THERMAL RIDGE MOVES
ACROSS THE CWA. SOUTH/SOUTHWEST 850MB WINDS OF 15-40 KT WILL HELP
KEEP THE BLYR MIXED...WITH OCCASIONAL GUSTINESS AT THE SFC.

ON TUESDAY THE STRONGEST 850-MB WINDS WILL BE ACROSS THE SD PLAINS
EAST OF THE BLKHLS...WITH SPEEDS OF 25-40 KT. MAY HIT BORDERLINE
WIND ADVY CONDITIONS ACROSS SCNTRL SD FROM 15-24Z. ACROSS NERN WY
THE WINDS WILL BE SOUTHWEST BEHIND A SFC TROUGH. ALSO ON TUESDAY
AFTN THE SFC DEWPTS SHOULD INCREASE TO 45-50F ACROSS MUCH OF THE SD
PLAINS (AHEAD OF THE SFC TROUGH) AS LAPSE RATES REACH 7.5 C/KM. THIS
WILL PRODUCE MLCAPE OF 100-250 J/KG WITH MLCIN ALMOST AS HIGH. EVEN
THOUGH A SHORT-WAVE TROUGH WILL BE MOVING ACROSS THE NRN ROCKIES...
LARGE-SCALE ASCENT WILL BE LACKING. THUS...DO NOT EXPECT ANY DEEP
MOIST CONVECTION DURING THE DAY.

ON TUESDAY NIGHT THE SHORT-WAVE TROUGH MOVES ACROSS MT WITH A SFC
TROUGH AND COLD FRONT MOVING THROUGH WRN SD. AGAIN...LIFT AND
MOISTURE WILL BE LACKING...THUS VERY LITTLE IN THE WAY OF PRECIP
EXPECTED. HOWEVER...SOME SMALL POPS ARE WARRANTED ACROSS PARTS OF
SRN SD WHERE CONVERGENCE ALONG THE SFC TROUGH/FRONT AND MUCAPE OF
250-500 J/KG MAY HELP INITIATE A FEW SHRA/TSRA.

&&

.LONG TERM...WEDNESDAY THROUGH MONDAY
ISSUED AT 121 PM MDT MON OCT 20 2014

WEAK UPPER TROF WILL CROSS THE REGION ON WEDNESDAY AND USHER
SLIGHTLY COOLER AIR INTO THE AREA. MOISTURE WILL BE LIMITED WITH
THIS SYSTEM WITH THE BEST CHANCE FOR ANY PRECIPITATION OVER SCNTRL
SD. THE UPPER RIDGE WILL THEN REBUILD OVER THE CNTRL CONUS AND
BRING DRY WX AND MUCH ABOVE AVERAGE TEMPS INTO THE WEEKEND. NEXT
TROF APPROACHES LATE IN THE WEEKEND.

&&

.AVIATION...FOR THE 18Z TAFS THROUGH 18Z TUESDAY
ISSUED AT 121 PM MDT MON OCT 20 2014

VFR CONDITIONS EXPECTED THROUGH TUESDAY.

&&

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

&&

$$

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




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