Area Forecast Discussion
Issued by NWS Rapid City, SD

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000
FXUS63 KUNR 020812
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
212 AM MDT TUE JUN 2 2015

.SHORT TERM...TODAY THROUGH WEDNESDAY NIGHT
ISSUED AT 208 AM MDT TUE JUN 2 2015

UPPER WAVE CONTINUES TO PUSH SHOWERS AND STORMS THROUGH THE
NORTHERN PLAINS...MAINLY ACROSS MT AND ND...AND DRIER AIR IS
MOVING IN. WITH THE SURFACE LOW OVER THE MT/ND/SD BORDERS...THE
STATIONARY FRONT IS DRAPED THROUGH OUR CWA. WINDS ARE SOUTHERLY
AROUND 10 KTS...AND TEMPERATURES ARE REMAINING IN THE 60S.

THE NORTHERN PLAINS WILL BE UNDER SOUTHWEST FLOW AS THE UPPER TROUGH
CONTINUES TO MOVE ON SHORE. AHEAD OF THE SURFACE LOW...WARM AND
MOIST AIR WILL ADVECT INTO THE REGION. TEMPS WILL WARM WELL INTO THE
80S ACROSS MUCH OF THE CWA...WITH DEW POINTS IN THE 60S. SLIGHTLY
COOLER HIGHS ARE EXPECTED OVER THE NORTHWESTERN CWA AS A COLD FRONT
SWEEPS THROUGH. MLCAPE VALUES WILL REACH 3000-4000 J/KG ACROSS
CENTRAL SD AND AROUND THE SOUTHERN BLACK HILLS BY MID AFTERNOON WITH
NEAR 30 J/KG CIN. FORECAST SOUNDINGS INDICATE CAPPING MAY INHIBIT
THUNDERSTORM DEVELOPMENT ACROSS CENTRAL SD...BUT THE CAP MAY BREAK
OVER THE SOUTHERN HILLS BY MID AFTERNOON. WITH NEAR 45 KTS 0-6KM
SHEAR OVER THE HILLS BY EVENING...WOULD NOT BE SURPRISED IF A
SUPERCELL WERE TO DEVELOP THERE. HOWEVER...THE POTENTIAL EXISTS FOR
STRONG TO SEVERE STORMS WITH LARGE HAIL AND DAMAGING WINDS TO
DEVELOP ACROSS MOST PARTS OF THE CWA. PRECIPITABLE WATER VALUES ARE
NEAR AN INCH AROUND AND EAST OF THE BLACK HILLS AGAIN...AND THE
POSSIBILITY REMAINS THAT HEAVY RAIN MAY AGGRAVATE FLOODING
CONDITIONS. HOWEVER...STORM MOTION IS A BIT STRONGER TODAY AT 15-
20KTS...SO WOULD NOT EXPECTED STORMS TO BE AS STATIONARY AS ON
MONDAY.

UPPER LOW OVER THE WEST COAST WILL CONTINUE TO EJECT ENERGY INTO THE
REGION WEDNESDAY...WITH CHANCES OF SHOWERS AND THUNDERSTORMS
CONTINUING. WITH AROUND 2500 J/KG MLCAPE AND 35 KTS EFFECTIVE SHEAR
ACROSS SOUTHERN SD...MAY BE A FEW STRONG TO SEVERE STORMS
THERE...BUT EXPECT THE MAJORITY OF THE SEVERE WEATHER TO BE FARTHER
SOUTH. HIGHS WEDNESDAY BEHIND THE COLD FRONT WILL BE IN THE 70S.

.LONG TERM...THURSDAY THROUGH MONDAY
ISSUED AT 208 AM MDT TUE JUN 2 2015

CLOSED UPPER LOW EXPECTED OVER THE WESTERN CONUS BY THE
END OF THE WEEK. THIS WILL SET THE STAGE FOR SPLIT FLOW WITH AN
ACTIVE NORTHERN STREAM REINFORCING A LL BAROCLINIC ZONE ACROSS THE
REGION THROUGH MUCH OF THE PERIOD. EJECTING IMPULSES EMANATING FROM
THE WESTERN CONUS UPPER TROUGH AS WELL AS PASSING NORTHERN STREAM
WAVES WILL SUPPORT AN ACTIVE FLOW PATTERN FOR THE REGION AS LL ESE
FLOW RETAINS APPRECIABLE LL MOISTURE INVOF THE REGION. THIS WILL
ALLOW FOR NEAR DAILY CHANCES FOR SHRA/TS IN MOST IF NOT ALL OF THE
FA THROUGH MOST OF THE PERIOD. MEAN FORECAST MODELS CONTINUE TO
FAVOR THUR/FRI AS THE BEST PERIOD FOR MORE WIDESPREAD PRECIP CHANCES
GIVEN THE EJECTION OF TWO APPRECIABLE JET STREAKS. RETAINED THE
HIGHEST POPS IN THIS PERIOD...WITH GENERALLY LOW TO SLIGHT CHANCES
THROUGH THE REMAINDER OF THE PERIOD. PERIODIC CHANCES FOR SEVERE
STORMS CAN ALSO BE EXPECTED ESP GIVEN FASTER FLOW ALOFT WITH
SUFFICIENT LL MOISTURE AND ESE UPSLOPE FLOW. SEASONAL TO SLIGHTLY
BELOW SEASONAL TEMPS ON TRACK THOROUGH THE PERIOD.

&&

.AVIATION...FOR THE 12Z TAFS THROUGH 12Z TUESDAY NIGHT ISSUED AT
208 AM MDT TUE JUN 2 2015

SCT SHRA WILL PERSIST ACROSS NE WY AND NW SD. VFR CONDITIONS
EXPECTED THROUGH THIS MRNG. SCT TSRA WILL REDEVELOP ACRS NERN WY
AND THE BLKHLS THIS AFTN...THEN SPREAD INTO WRN SD THIS EVE...WITH
MFVR/IFR CONDITIONS IN HEAVIER PCPN.

&&

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

$$

SHORT TERM...POJORLIE
LONG TERM...JC
AVIATION...JC



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