Area Forecast Discussion
Issued by NWS Rapid City, SD

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000
FXUS63 KUNR 302038
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
238 PM MDT TUE JUN 30 2015

.SHORT TERM...THIS EVENING THROUGH WEDNESDAY NIGHT
ISSUED AT 237 PM MDT TUE JUN 30 2015

UPPER RIDGING ACROSS THE WRN CONUS CONTINUES TODAY WITH WNW TO NW
FLOW OVER THE NRN PLAINS. A STRONG S/W IS CROSSING ERN MT/WRN ND.
SURFACE ANALYSIS SHOWS LOW PRES ACROSS ERN MT...THRU THE
BLKHLS...INTO THE NEB PNHDL. KUDX SHOWS WEAK SHRA ACTIVITY
DEVELOPING OVER THE LAST HOUR ACROSS PTNS OF NE WY/WRN SD...AND TSRA
EAST OF THE CWA IN NCNTRL SD. MLCAPE OF 1000-1500 J/KG IS EXPECTED
THIS AFTN WITH STRONG EFCTV SHEAR...SO SOME SUPERCELL DEVELOPMENT IS
EXPECTED LATE THIS AFTN INTO THE EVNG MAINLY ACROSS THE WRN SD
PLAINS INTO THE BLKHLS. BEST CHANCE FOR PRECIP WILL BE OVER NW SD
INTO CNTRL SD WHERE BEST FORCING WILL BE. LARGE HAIL WILL BE MAIN
THREAT THOUGH SOME DAMAGING WINDS COULD STILL BE POSSIBLE. STORMS
WILL SHIFT SOUTH/EAST OF THE CWA OVERNIGHT.

NW FLOW CONTINUES WED AS THE UPPER PATTERN CHANGES LITTLE. SLIGHTLY
COOLER TEMPS ARE EXPECTED AS LOW LEVEL FLOW BECOMES NWRLY BEHIND THE
DEPARTING SURFACE LOW. CONVECTION WILL BE ONGOING MUCH OF THE DAY
TOMORROW ACROSS CNTRL SD..PERHAPS INTO THE NW SD CWA. OTHERWISE MUCH
OF THE DAYTIME HOURS ARE EXPECTED TO BE QUIET. AN UPPER WAVE IS
PROGGED TO CROSS ERN MT INTO WRN SD BRINGING NIGHTTIME CONVECTION TO
THE AREA. MLCAPE WILL BE ANYWHERE FROM 1000-2000 J/KG WITH DECENT
ENOUGH SHEAR FOR SUPERCELL/SPLITTING STORMS.

.LONG TERM...THURSDAY THROUGH TUESDAY
ISSUED AT 237 PM MDT TUE JUN 30 2015

NORTHWEST FLOW ALOFT WILL PREVAIL THURSDAY THROUGH THE WEEKEND AS
SHORT-WAVE TROUGHS TOP THE WRN CONUS RIDGE AND MOVE ACROSS THE NRN
PLAINS...RESULTING IN ISOLD-SCT SHRA/TSRA FROM TIME TO TIME.
EXPECT WAVES BOTH THURSDAY AND FRIDAY NIGHTS...FOLLOWED BY A
STRONG TROUGH/UPPER LOW SETTING UP ACROSS CANADA SATURDAY AND
SUNDAY. THIS WILL PUSH A COLD FRONT SOUTH ACROSS THE REGION
SATURDAY NIGHT AND SUNDAY...AND WILL BE ASSOCIATED WITH A
SCATTERED LINE OF THUNDERSTORMS AND GUSTY NORTHWEST WINDS IN ITS
WAKE. AFTER THAT THERE IS NOTABLE DISAGREEMENT BETWEEN THE GFS AND
ECMWF FOR NEXT WEEK AS THE ECMWF KEEPS A STRONGER RIDGE IN THE WRN
CONUS WHILE THE GFS HAS A TROUGH IN THE WRN CONUS AND A RIDGE IN
THE CNTRL CONUS. ENSEMBLE GUIDANCE IS MORE IN LINE WITH THE GFS.
THE RESULT OF THIS WOULD BE TEMPERATURES A BIT ABOVE AVERAGE AND
CHANCES OF TSRA AS ZONAL-TO-SOUTHWEST FLOW ALOFT SETS UP.

&&

.AVIATION...FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY
ISSUED AT 237 PM MDT TUE JUN 30 2015

VFR CONDITIONS EXPECTED THROUGH THE PERIOD...WITH THE EXCEPTION
OF POSSIBLE IFR/MVFR CIGS WED MRNG OVER NWRN SD AS STRATUS MOVES
SOUTH OUT OF ND. IF THIS DOES OCCUR...EXPECT IT TO MOVE EAST BY
18Z. OTHERWISE...SCT SHRA/TSRA EXPECTED TNGT OVER NERN WY AND
NWRN-WRN SD...WITH THE BEST CHANCE OVER NWRN SD. MOST ACTIVITY
SHOULD BE EAST OF THE AREA BY 06Z.

&&

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

$$

SHORT TERM...13
LONG TERM...BUNKERS
AVIATION...BUNKERS



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