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000
FXUS63 KUNR 221520
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
920 AM MDT WED MAY 22 2013

.UPDATE...
ISSUED AT 913 AM MDT WED MAY 22 2013

NORTHEASTERLY WINDS ARE PUSHING MOISTURE AGAINST THE
HILLS...CREATING SOME PATCHY FOG ACROSS THE FOOTHILLS AND AREAS TO
THE EAST. MODEL SOUNDINGS SHOW THE LOW CLOUDS LIFTING AROUND
MIDDAY. DEPENDING ON HOW LONG THESE LOW CLOUDS STICK
AROUND...TEMPERATURES MAY NOT GET AS WARM...SO WILL HAVE TO
MONITOR THAT AS THE DAY GOES ON. REST OF THE FORECAST LOOKS ON
TRACK.

&&

.SHORT TERM...TODAY THROUGH THURSDAY NIGHT
ISSUED AT 218 AM MDT WED MAY 22 2013

CURRENT SURFACE MAP SHOWS WEAK RIDGE OF HIGH PRESSURE ACROSS THE
WESTERN DAKOTAS. UPPER LOW THAT HAS BEEN OVER THE EASTERN DAKOTAS
THE PAST FEW DAYS IS SHIFTING EASTWARD...WITH MOST OF THE SHOWERS
ACTIVITY OVER EASTERN SOUTH DAKOTA. ISOLATED SHOWERS/DRIZZLE
POSSIBLE ACROSS WESTERN SOUTH DAKOTA THIS MORNING. ABUNDANT LOW
LEVEL STRATUS WILL REMAIN ACROSS MUCH OF THE FORECAST AREA THROUGH
THE DAY AS WINDS BECOME NE-E THIS WILL KEEP HIGHS AROUND 10
DEGREES BELOW AVERAGE.

DEEP UPPER LOW OVER THE PACIFIC NORTHWEST WILL BEGIN TO INFLUENCE
THE AREA THURSDAY WITH STRONG PRESSURE FALLS ACROSS
MONTANA/WYOMING WITH DEVELOPING SURFACE LOW. TIGHT PRESSURE
GRADIENT ACROSS NORTHEAST WYOMING/WESTERN SOUTH DAKOTA WILL RESULT
IN WINDY CONDITIONS. SOME WEAK SURFACE BASED INSTABILITY ACROSS
NORTHEAST WYOMING AND THE BLACK HILLS THURSDAY AFTERNOON.
HOWEVER...WITH LACK OF UPPER LEVEL FORCING AND STRONG CAP WIN
PLACE WILL NOT ADD THUNDERSTORMS TO THE FORECAST.

&&

.LONG TERM...FRIDAY THROUGH TUESDAY
ISSUED AT 218 AM MDT WED MAY 22 2013

SOUTHWESTERLY FLOW ALOFT DEVELOPS OVER THE REGION FRIDAY AS RIDGE
SHIFTS TO THE EAST AND UPPER LOW SPINS IN PLACE OVER THE PACIFIC NW.
THIS PATTERN WILL PERSIST THROUGH AT LEAST THE FIRST HALF OF NEXT
WEEK AND BRING DAILY CHANCES FOR SHOWERS AND THUNDERSTORMS. LEE
TROUGH/DRY LINE WILL REMAIN NEARLY STATIONARY ACROSS EASTERN MT AND
EASTERN WY THROUGH THE PERIOD. MOIST SOUTH/SOUTHEAST LOW LEVEL FLOW
WILL PERSIST TO THE EAST OF THE TROUGH ACROSS THE BLACK HILLS AREA
AND THE PLAINS TO THE EAST. THIS IS WHERE THE BETTER CHANCES FOR
THUNDERSTORMS AND POTENTIAL SEVERE WEATHER WILL BE...ESPECIALLY
SUNDAY AND EARLY NEXT WEEK. TEMPERATURES WILL RISE TO ABOVE AVERAGE
LEVELS ON FRIDAY AND PERSIST THROUGH THE HOLIDAY WEEKEND...WITH THE
WARMEST TEMPS ACROSS WESTERN PORTIONS OF THE CWA.

&&

.AVIATION...FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING
ISSUED AT 527 AM MDT WED MAY 22 2013

ISOLATED LIGHT SHOWERS AND DRIZZLE WILL PERSIST ACROSS AREAS
EAST OF THE BLACK HILLS THIS MORNING. FAIRLY WIDESPREAD MVFR/IFR
CONDITIONS WILL CONTINUE ACROSS THE FORECAST AREA THIS MORNING AS
SIGNIFICANT LOW LEVEL MOISTURE REMAINS. CONDITIONS WILL GENERALLY
IMPROVE TO VFR OVER NORTHEASTERN WYOMING BY MIDDAY...AND OVER MUCH
OF WESTERN SOUTH DAKOTA BY LATE IN THE AFTERNOON. HOWEVER...AT LEAST
SOME AREAS OF MVFR/IFR CONDITIONS ARE LIKELY TO REDEVELOP ACROSS THE
PLAINS TONIGHT.


&&

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

$$

UPDATE...POJORLIE
SHORT TERM...7
LONG TERM...26
AVIATION...26