Area Forecast Discussion
Issued by NWS Rapid City, SD

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000
FXUS63 KUNR 010830
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
230 AM MDT MON JUN 1 2015

.SHORT TERM...TODAY THROUGH TUESDAY NIGHT
ISSUED AT 230 AM MDT MON JUN 1 2015

UPPER RIDGE AXIS IS OVER THE ROCKIES WITH SOME
HIGH CLOUDS STREAMING INTO THE NORTHERN PLAINS...AND A TROUGH IS
PUSHING INTO THE WEST COAST. SURFACE LOW PRESSURE IS MOVING INTO
MT...WITH ASSOCIATED STATIONARY/WARM FRONT JUST WEST OF THE CWA.
WINDS ARE GENERALLY SOUTHERLY...AND TEMPERATURES ARE IN THE 50S.

AS UPPER TROUGH PUSHES THE RIDGE EASTWARD TODAY...THE NORTHERN
PLAINS WILL BE UNDER SOUTHWEST FLOW AND THE SURFACE LOW PRESSURE
SYSTEM WILL APPROACH THE DAKOTAS. TEMPERATURES WILL WARM INTO THE
80S AND MLCAPE VALUES WILL REACH 2000-3000 J/KG BY MID-AFTERNOON.
SHOWERS AND THUNDERSTORMS ARE EXPECTED TO BEGIN DEVELOPING ACROSS
NORTHEAST WYOMING AND THE BLACK HILLS EARLY THIS AFTERNOON ALONG AND
EAST OF THE FRONT...GRADUALLY MOVING EASTWARD THROUGH THE EVENING.
SOME STRONG TO SEVERE THUNDERSTORMS ARE POSSIBLE...ESPECIALLY ACROSS
NORTHWEST SD...WHERE HIGHER CAPE VALUES WILL BE COLLOCATED WITH BEST
0-6KM SHEAR OF 30-40 KTS.

LOW PRESSURE SYSTEM WILL TRANSITION EASTWARD ON TUESDAY...PUSHING
THE WARM FRONT INTO CENTRAL SD AND DRAGGING A COLD FRONT INTO
NORTHEASTERN WY AND WESTERN SD. HIGHS AGAIN WILL WARM INTO THE 70S
AND 80S...ALTHOUGH MET AND MAV GUIDANCE HAVE A 10-DEGREE DIFFERENCE
ACROSS THE NORTHWESTERN CWA BECAUSE OF UNCERTAINTIES WITH THE
TIMING/INTENSITY OF THE COLD FRONT. NONETHELESS...WARM TEMPERATURES
COMBINED WITH DEW POINTS IN THE 60S WILL CREATE AN UNSTABLE
ENVIRONMENT BY TUESDAY AFTERNOON. THEREFORE SHOWERS AND
THUNDERSTORMS ARE EXPECTED AGAIN TUESDAY AFTERNOON AND
EVENING...SOME OF WHICH COULD BE SEVERE. MLCAPE VALUES ACROSS
CENTRAL SD REACH 3000-4000 J/KG BY THE AFTERNOON...WITH LAPSE RATES
OF 8-9 C/KM. SHEAR ACROSS CENTRAL SD IS NOT AS IMPRESSIVE AS FARTHER
WEST...WHERE CAPE ISN`T AS HIGH. HOWEVER...INGREDIENTS COULD PRODUCE
SEVERE WEATHER ACROSS ANY PART OF THE CWA TUESDAY...WITH SUPERCELLS
CAPABLE OF STRONG WINDS AND LARGE HAIL. HEAVY RAIN OVER ALREADY
SATURATED GROUND MAY RESULT IN FLASH FLOODING. BEST EHI AND 0-1KM
HELICITY WILL BE ACROSS CENTRAL SD...SO BELIEVE THE TORNADO THREAT
WILL BE EAST OF OUR CWA. OVERALL...TUESDAY LOOKS TO BE VERY ACTIVE.

.LONG TERM...WEDNESDAY THROUGH SUNDAY
ISSUED AT 230 AM MDT MON JUN 1 2015

OVERALL MODELS ARE IN GOOD AGREEMENT FOR THE EXTENDED
PERIOD. AN UPPER TROUGH WILL DEEPEN ACROSS THE WRN CONUS AND PERSIST
THROUGH THE REST OF THE WEEK. SW FLOW ALOFT ACROSS THE NRN PLAINS
WILL BRING CONTINUED CHANCES FOR SHOWERS AND THUNDERSTORMS. TIMING
OF ENERGY EJECTING FROM THE WESTERN TROUGH WILL RESULT IN WIDESPREAD
PRECIPITATION CHANCES...ESPECIALLY WEDNESDAY NIGHT AND THURSDAY AND
AGAIN FRIDAY NIGHT INTO THE WEEKEND. TEMPERATURES WEDNESDAY THROUGH
EARLY NEXT WEEK WILL BE AROUND AVERAGE.

&&

.AVIATION...FOR THE 12Z TAFS THROUGH 12Z MONDAY NIGHT ISSUED AT
230 AM MDT MON JUN 1 2015

TSRA WILL DEVELOP THIS AFTN/EVNG ACRS NERN WY AND THE
BLKHLS AREA...WITH MVFR CONDITIONS IN HEAVIER PCPN.

&&

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

$$

SHORT TERM...POJORLIE
LONG TERM...MLS
AVIATION...MLS



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