Area Forecast Discussion
Issued by NWS Rapid City, SD

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000
FXUS63 KUNR 300823
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
223 AM MDT SAT MAY 30 2015

.SHORT TERM...TODAY THROUGH SUNDAY NIGHT
ISSUED AT 207 AM MDT SAT MAY 30 2015

UPPER ANALYSIS SHOWS A BROAD UPPER RIDGE TO THE WEST OF THE REGION
THIS MORNING. LATEST SURFACE ANALYSIS SHOWS A NARROW BAND OF HIGH
PRESSURE OVER THE DAKOTAS.

THE SFC HIGH WILL SHIFT EASTWARD TODAY. BREEZY SOUTHERLY RETURN
FLOW DEVELOPING ON THE WEST SIDE OF THE HIGH WILL HELP TO INCREASE
LL MOISTURE OVER NERN WY AGAIN THIS AFTN. A WEAK SHORTWAVE
COMBINED WITH 850-700MB THETA-E ADVECTION WILL CREATE A SLIGHT
CHANCE OF THUNDERSTORMS OVER PARTS OF FAR NORTHEASTERN WYOMING
LATE THIS AFTERNOON WITH THE CHANCE OF THUNDERSTORMS SPREADING
EASTWARD INTO MAINLY NORTHWESTERN SOUTH DAKOTA THIS EVENING.

ON SUNDAY THE UPPER RIDGE WILL INCREASE IN AMPLITUDE OVER THE
WESTERN THIRD OF THE CONUS AND HIGH TEMPERATURES WILL WARM TO
AROUND THE AVERAGE FOR THIS TIME OF YEAR. INSTABILITY DUE TO LL
MOISTURE AND DIURNAL HEATING WILL COMBINE WITH ANOTHER WEAK
SHORTWAVE TO PRODUCE A CHANCE OF THUNDERSTORMS ON SUNDAY AFTN OVER
NERN WY...THE BLKHLS AND FAR SWRN SD LATE SUNDAY AFTN WITH A
SLIGHT CHANCE OF THUNDERSTORMS OVER MUCH OF THE REST OF THE AREA
ON SUNDAY AFTN.

.LONG TERM...MONDAY THROUGH FRIDAY
ISSUED AT 207 AM MDT SAT MAY 30 2015

RIDGE AXIS MOVES OVER THE NORTHERN PLAINS
MONDAY...ALLOWING ABOVE AVERAGE TEMPERATURES TO RETURN TO THE AREA.
A WEAK WAVE WILL PASS THROUGH THE RIDGE MONDAY AFTERNOON AND
EVENING. WITH MLCAPE VALUES NEAR 2000 J/KG OVER WESTERN SD...SOME
STRONG TO SEVERE STORMS MAY BE POSSIBLE...ALTHOUGH BEST SHEAR WILL
BE FARTHER EAST. CHANCES FOR SHOWERS AND THUNDERSTORMS ARE EXPECTED
FOR THE REMAINDER OF THE WEEK AS A WESTERN TROUGH REDEVELOPS AND
UPPER FLOW OVER THE NORTHERN PLAINS BECOMES SOUTHWESTERLY. HIGHS
NEXT WEEK WILL BE NEAR SEASONAL AVERAGES...WARMEST MONDAY AND
TUESDAY.

&&

.AVIATION...FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING
ISSUED AT 207 AM MDT SAT MAY 30 2015

FOG/LOW STRATUS WITH MVFR/IFR CIGS/VSBYS OVER THE
SOUTHERN/EASTERN FOOTHILLS AND INTO NORTHEAST WY WILL PERSIST INTO
THIS MORNING BEFORE DISSIPATING. VFR CONDITIONS ARE EXPECTED FROM
MIDDAY THROUGH THE FORECAST PERIOD.


&&

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

$$

SHORT TERM...10
LONG TERM...POJORLIE
AVIATION...POJORLIE



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