680
FXUS63 KUNR 162107
AFDUNR
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
307 PM MDT WED MAY 16 2012
DISCUSSION
BROAD...FLAT LONG WAVE RIDGE ABOUT 115W WITH CLOSED LOW IN THE
MIDST OF THE RIDGE SRN UT THIS MORNING. WV AND NAM SHOW HINTS OF
WEAK SHORT WAVES IN WESTERLY FLOW ACROSS NRN ROCKIES. AFTN
CONVECTION DVLPG OVER HIER TERRAIN WY...BUT LIMITED BY QUITE DRY
AIR MASS. UT LOW IS FCST TO MOVE MOSTLY E WARD WITH STILL ANOTHER
WK SHORT WAVE CROSSING THE CWA EARLY TOMORROW AS SWLY FLOW DVLPS
BEHIND THE LOW. A SECOND SHORT WAVE...LOW NOW OVER THE PAC IS FCST
TO APPROACH THE CWA THURSDAY NIGHT AND FRI.
GFS...NAM AND CONVECTION ALLOWING MODELS SHOW DVLPMNT OF
CONVECTIVE SYSTEM OVER WY...MOVING INTO SE MT AND NW SD EARLY
FRIDAY MORNING. TOO FAR OUT TO BE REALLY CONFIDENT...BUT LOOKS
REASONABLE. SCULPTED POPS TO FIT THIS SYSTEM. FLWG THIS
DVELPMT...A MESO BOUNDARY IS PUSHED S WARD ACROSS THE CWA BY THE
NAM...EFFECTIVELY BECOMING THE SYNOPTIC SCALE COLD FRONT LATER ON FRIDAY.
WIDESPREAD 500 MB Q VECTOR CONVERGENCE AND PRECIP ARE FCST TO DVLP
MOSTLY BEHIND THE FRONT FRIDAY NIGHT AND SATURDAY.
BEST CHANCE FOR POSSIBLE SVR WX APPEARS TO BE ON FRIDAY AFTN AND
EARLY EVG OVER SE PORTIONS OF OUR CWA WITH GOOD DIFLUENCE FCST AT
300 MB...WEAK LOW PRESSURE AT THE SFC...AND SRLY LOW LEVEL FLOW.
MAIN LIMITING FACTOR MAY WELL AGAIN BE MOISTURE AS SRLY FLOW LOOKS
LIKE IT WILL BE DRY OVER OUR CWA WITH MOST MOISTURE FARTHER E.
COOLING BEHIND MESO SYSTEM/COLD FRONT AFTER ON THURSDAY NIGHT AND
FRIDAY. MOSTLY FOLLOWED GUIDANCE IN TEMPS WITH LITTLE CHANGE FROM
PREVIOUS FCSTS.
EXTENDED...UPPER TROF AXIS PUSHES OVER THE AREA LATE SATURDAY...WITH
PRECIP TAPERING OFF FROM WEST TO EAST AS RIDGE STARTS TO BUILD IN.
TEMPERATURES WILL BE NEAR TO SLIGHTLY BELOW AVG SAT IN THE WAKE OF A
PASSING COLD FRONT. TEMPERATURES WILL SLOWLY WARM THROUGH THE FIRST
PART OF NEXT WEEK AS THE RIDGE PUSHES OVER...WHILE CONDITIONS REMAIN
DRY. THE NEXT TROF WILL START ITS APPROACH BY LATE TUESDAY INTO
WEDNESDAY...BRINGING THE NEXT CHANCES FOR PRECIP.
AVIATION
18Z TAFS
VFR CONDITIONS WILL PREVAIL THROUGH THE FORECAST PERIOD. SRLY WINDS
WILL SLOWLY DIMINISH TONIGHT THOUGH MAY REMAIN GUSTY...PARTICULARLY
OVER S CNTRL SD. ISOLD -TS WILL ALSO BE POSSIBLE LATE THIS AFT INTO
THIS EVE OVER NERN WY AND FAR WRN SD. WINDS WILL BE ERRATIC AND
GUSTY INVOF ANY TS. WINDS WILL START TO SWITCH W TO NW THUR MORN
OVER NERN WY AND WRN SD AS A SFC TROF PUSHES IN.
UNR WATCHES/WARNINGS/ADVISORIES
SD...NONE.
WY...NONE.
SHORT TERM...BARBER
LONG TERM....77
AVIATION...77
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page