Area Forecast Discussion
Issued by NWS Rapid City, SD

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FXUS63 KUNR 020903
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
303 AM MDT SUN AUG 2 2015

.SHORT TERM...TODAY THROUGH MONDAY NIGHT
ISSUED AT 303 AM MDT SUN AUG 2 2015

BROAD UPPER RIDGING WILL REMAIN ACROSS THE WRN CONUS TODAY. LARGE
SCALE SUBSIDENCE AND DRY AIR IN PLACE WILL KEEP SKIES MOSTLY SUNNY
TODAY. NE WINDS WILL DEVELOP THROUGH THE DAY...BECOMING E/SE
TONIGHT AS RETURN FLOW SETS BACK UP OVER THE CWA. HIGHS WILL REACH
THE MID 80S TO MID 90S. THETA E ADVECTION WILL DEVELOP ACROSS THE
AREA MONDAY AS RETURN FLOW INCREASES. THE BLACK HILLS INTO SW SD
MAY SEE ISOLATED STORMS MON AFTN...HOWEVER CHANCES WILL INCREASE
INTO THE EVENING AND CONTINUE INTO TUESDAY AHEAD OF A STRONG WAVE
CROSSING THE NRN TO CNTRL ROCKIES. BEST CHANCE FOR OVERNIGHT
STORMS WILL BE ACROSS PTNS OF NE WY...THROUGH THE BLKHLS AREA
INTO SW/SCNTRL SD.

.LONG TERM...TUESDAY THROUGH SATURDAY
ISSUED AT 303 AM MDT SUN AUG 2 2015

CHANCE FOR THUNDERSTORMS INCREASE THIS WEEK...WITH BEST
CHANCE COMING TUESDAY INTO WEDNESDAY. 00Z MODELS CONTINUE TO SHOW
UPPER IMPULSE KNOCKING DOWN RIDGE TUESDAY/TUESDAY NIGHT. SLIGHT
DIFFERENCES WITH GFS/ECMWF/GEM...TRACKING SURFACE LOW ACROSS
SOUTHERN SOUTH DAKOTA/NEBRASKA. 00Z NAM  MUCH STRONGER WITH SURFACE
TO 700MB LOW THAN THE OTHER MODELS. IT APPEARS NAM IS SUFFERING WITH
CONVECTIVE FEEDBACK ISSUES...AS IT DUMPS 6+ INCHES OF RAIN OVER THE
BLACK HILLS. AREA WILL BE PRIMED FOR THUNDERSTORMS AS LOW LEVEL
EASTERLY FLOW INCREASES BL MOISTURE AND MID LEVEL MOISTURE SURGES
NORTHWARD FROM THE SOUTHWESTERN U.S. CAPE/SHEAR SUGGEST MARGINAL
SEVERE STORMS POSSIBLE TUESDAY...BUT MAIN THREAT WILL BE LOCALLY
HEAVY RAIN. WENT WITH COOLER TEMPERATURES FOR HIGHS
TUESDAY/WEDNESDAY WITH ABUNDANT CLOUD COVER/PRECIPITATION.

THUNDERSTORM CHANCES CONTINUE INTO THE WEEKEND. GFS/ECMWF BRING NEXT
UPPER TROF THROUGH THE NORTHERN PLAINS THURSDAY. FLAT UPPER RIDGE
THEN SETS OVER THE ROCKIES AS TROF MOVES INTO THE WESTERN CONUS.
SEVERAL WEAK SHORTWAVES MOVE OVER THE RIDGE INTO THE NORTHERN
PLAINS.

&&

.AVIATION...FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING
ISSUED AT 303 AM MDT SUN AUG 2 2015

VFR CONDITIONS EXPECTED THROUGH TONIGHT.

&&

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

$$

SHORT TERM...13
LONG TERM...7
AVIATION...7



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