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000
FXUS63 KUNR 111731
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
1131 AM MDT SAT MAY 11 2013

.SHORT TERM...TODAY THROUGH SUNDAY NIGHT
ISSUED AT 308 AM MDT SAT MAY 11 2013

LATEST UPPER ANALYSIS SHOWS A TROUGH OVER THE EASTERN CONUS AND A
RIDGE OVER THE WEST...LEADING TO NORTHWEST FLOW ALOFT OVER THE
FORECAST AREA. AT THE SURFACE...DRY HIGH PRESSURE IS BUILDING INTO
THE AREA FROM THE NORTHWEST. LATEST MODELS ARE SHOWING WEAK INSTABILITY
DEVELOPING OVER THE BLACK HILLS TODAY...HOWEVER WITH DRY AIR IN
PLACE EXPECT ONLY SOME CU TO DEVELOP OVER THE HILLS THIS
AFTERNOON. SLIGHTLY STRONGER INSTABILITY WILL DEVELOP ALONG THE
WESTERN EDGE OF THE HIGH THIS AFTERNOON...SOUTH AND WEST OF THE
FORECAST AREA SO WILL LEAVE THE FORECAST DRY FOR THIS AFTERNOON
AND EVENING. HIGH TEMPERATURES WILL BE IN THE THE MID TO UPPER 60S
OVER NORTHEASTERN WYOMING AND IN THE LOWER 60S OVER WESTERN SOUTH
DAKOTA. TEMPERATURES ON SUNDAY WILL BE WARMER...RANGING FROM THE
LOWER 80S OVER NORTHEASTERN WYOMING TO THE LOWER 70S OVER CENTRAL
SOUTH DAKOTA. WEAK INSTABILITY WILL AGAIN DEVELOP OVER THE BLACK
HILLS ON SUNDAY AFTERNOON BUT THE CHANCE OF PRECIPITATION REMAINS
MINIMAL AS THE UPPER RIDGE BEGINS TO BUILD IN FROM THE WEST AND
SYNOPTIC SCALE SUBSIDENCE DEVELOPS ALOFT.

&&

.LONG TERM...MONDAY THROUGH FRIDAY
ISSUED AT 308 AM MDT SAT MAY 11 2013

UPPER LEVEL RIDGE BUILDS OVER THE NORTHERN PLAINS FOR EARLY NEXT
WEEK. THIS WILL BRING DRY CONDITIONS AND VERY WARM TEMPERATURES TO
THE AREA. THERMAL RIDGE CROSSES THE CWA ON MONDAY...BRINGING HIGHS
WELL INTO THE 80S ON THE PLAINS...WITH SOME LOWER 90S LIKELY TO THE
EAST OF THE BLACK HILLS. UPPER RIDGE FLATTENS A BIT FOR THE
REMAINDER OF THE WEEK...AS WEAK DISTURBANCES MOVE NORTH OF THE
REGION. THE TIMING OF THESE DISTURBANCES IS STILL RATHER UNCERTAIN
AT THIS POINT...BUT WILL KEEP SLIGHT CHANCES FOR SHOWERS AND
THUNDERSTORMS ACROSS A GOOD PORTION OF THE CWA FOR THURSDAY AND
FRIDAY. THE GFS AND ECMWF ARE BOTH SHOWING THE POTENTIAL FOR A
STRONGER SYSTEM TO IMPACT THE AREA BY NEXT WEEKEND AND BRINGING
BETTER CHANCES FOR SHOWERS AND THUNDERSTORMS.

&&

.AVIATION...FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON
ISSUED AT 1131 AM MDT SAT MAY 11 2013

VFR CONDITIONS ARE EXPECTED THROUGH SUNDAY MORNING.

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

$$

SHORT TERM...10
LONG TERM...15
AVIATION...26