Area Forecast Discussion
Issued by NWS Rapid City, SD

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FXUS63 KUNR 222306
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
506 PM MDT FRI MAY 22 2015

.SHORT TERM...THIS EVENING THROUGH SATURDAY NIGHT
ISSUED AT 238 PM MDT FRI MAY 22 2015

THE UPPER LOW CURRENTLY LOCATED OVER THE SWRN CONUS WILL CONTINUE
TO AFFECT THE WEATHER OVER THE FORECAST AREA THROUGH THE WEEKEND.
12Z SOUNDINGS AND MODEL FORECASTS INDICATE A 110KT 300MB JET
STREAK ROUNDING THE UPPER LOW WILL MOVE NORTHWARD TOWARD THE
FORECAST AREA TONIGHT. THE LEAD SHORT-WAVE TROUGH WILL SHEAR OUT
AS IT MOVES SLOWLY NORTH ACROSS THE CWA TONIGHT. FORCING WILL BE
RELATIVELY WEAK WITH THE BEST LIFT PASSING TO THE EAST OF THE
FORECAST AREA. THE E-W ORIENTED BAND OF RAIN OVER NRN NEBRASKA IS
EXPECTED TO PUSH SLIGHTLY NORTHWARD INTO THE SWRN AND SC SD PARTS
OF THE FORECAST AREA LATE THIS AFTN-EARLY THIS EVENING. ISOLD-SCT
SHOWERS ARE EXPECTED OVER NERN WY AND PARTS OF FAR WRN SD TONIGHT.

SATURDAY...SOUTHWEST FLOW ALOFT WILL STRENGTHEN AS THE HUDSON BAY
AREA LOW MOVES SOUTHEAST AND THE SWRN CONUS LOW MOVES TO THE FOUR-
CORNERS AREA BY MID-DAY. A SHORT-WAVE TROUGH WILL APPROACH THE
FORECAST AREA FROM THE SOUTH DURING THE DAY...WITH INCREASING
PWATS AND SBCAPES OF 250-500 J/KG...MAINLY OVER THE SRN HALF OF
THE FA. EXPECT SCT SHRA/TSRA ACROSS THE CWA INCREASING IN COVERAGE
DURING THE AFTN. THE SEVERE POTENTIAL WILL BE LOW BECAUSE OF THE
LIMITED BUOYANCY AND MODEST MIDLEVEL LAPSE RATES.

ON SATURDAY NIGHT THE MODELS AGREE ON BRINGING A STRONGER JET
STREAK AND SHORTWAVE TROUGH ACROSS THE AREA INCREASING THE
SYNOPTIC SCALE LIFT. THIS WILL LEAD TO A GOOD ROUND OF PCPN THAT
WILL PERSIST INTO SUNDAY. WILL KEEP THE ESF GOING FOR THE HEAVY
RAIN POTENTIAL.

.LONG TERM...SUNDAY THROUGH FRIDAY
ISSUED AT 238 PM MDT FRI MAY 22 2015

MEDIUM RANGE MODELS IN PRETTY GOOD AGREEMENT ON
FEATURES THROUGH EARLY NEXT WEEK. UPPER LEVEL LOW WILL LIFT NORTH
AND EAST ACROSS THE REGION ON SUNDAY AND GRADUALLY WEAKEN AS IT
MOVES NORTHEAST OF THE AREA SUNDAY NIGHT AND MONDAY. FAIRLY
WIDESPREAD AREA OF SHOWERS AND ISOLATED THUNDERSTORMS WILL DEVELOP
AND MOVE ACROSS THE AREA ON SUNDAY. LOCALLY HEAVY RAINFALL IS
POSSIBLE...BUT THREAT FOR SEVERE STORMS LOOKS MINIMAL AT THIS POINT.
SHOWERS WILL TAPER OFF IN COVERAGE AND INTENSITY SUNDAY NIGHT INTO
MONDAY. HIGHS ON SUNDAY AND MEMORIAL DAY WILL BE IN THE 50S AND
LOWER 60S.

BEHIND THE SYSTEM...FLOW ALOFT WILL BE FROM THE WEST-SOUTHWEST NEXT
WEEK. THIS WILL KEEP ACTIVE WEATHER PATTERN IN PLACE...WITH DAILY
CHANCES FOR SHOWERS AND THUNDERSTORMS EXPECTED THROUGH THE WEEK. THE
BETTER CHANCES AT THIS POINT LOOK TO BE WEDNESDAY AND THURSDAY.
TEMPERATURES WILL RETURN TO NEAR AVERAGE LEVELS IN MOST AREAS FOR
TUESDAY AND THE REST OF THE WEEK.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 504 PM MDT FRI MAY 22 2015

SCATTERED SHOWERS AND AREAS OF MVFR CONDITIONS WILL
SLOWLY PUSH NORTH INTO SOUTHERN PORTIONS OF NORTHEAST WY...SOUTHERN
SD...AND THE BLACK HILLS THIS EVENING. OTHERWISE...VFR CONDITIONS
ARE EXPECTED ELSEWHERE THROUGH THE EARLY EVENING. SCATTERED
SHOWERS WILL CONTINUE TONIGHT INTO SATURDAY MORNING... MOSTLY
ACROSS NORTHEAST WY...THE BLACK HILLS...AND SOUTHERN SD...WITH
MVFR/IFR CONDITIONS DEVELOPING ACROSS MUCH OF NORTHEAST WY AND
WESTERN SD OVERNIGHT. MVFR/IFR CONDITIONS WITH SHOWERS WILL
PERSIST THROUGH SATURDAY AFTERNOON.

&&

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

$$

SHORT TERM...10
LONG TERM...26
AVIATION...7


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