935
FXUS63 KFSD 020934
AFDFSD
AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NATIONAL WEATHER SERVICE SIOUX FALLS SD
330 AM CST TUE DEC 2 2008
DISCUSSION
STG WARM ADVECTN WILL TRY TO MAKE THE MILD AIR FULLY FELT AT THE SFC
TDA...WHICH OF COURSE IT WONT BE AT THIS TIME OF YEAR DESPITE LIKELY
DECENT SUNSHINE INTO THE START OF THE AFTN. STILL WHAT WE HAVE BEEN
GOING FOR WITH 40S TO LOWER 50S FOR HIGHS LOOKS GOOD. CLDS WILL BE
INCRG SLWLY FROM THE NW FROM ARND NOON TO THE END OF TDA AND OF
COURSE INTO THIS EVE. DVLPMNT OF BAND OF PCPN THIS EVE SUPPORTED BY
DECENT FRONTOGENESIS FROM SWRN TO ECNTRL FCST AREA LOOKS LIKE A GOOD
BET. WILL GO LIKELY POPS THIS AREA AND INTO THE SERN FCST AREA FOR
TNGT. XCP FOR PSBL -RA SW IN THE ERY EVE....PCPN SHUD BE SNOW AS RPD
COOLING SPREADS ACRS AREA FROM THE N. GFS CONTS TO BE A BETTER
SUPPORTER OF DECENT PCPN BAND THAN THE NAM BUT IT IS SUPPORTED BY
THE NAM AND CANADIAN...AND EVEN THE NAM ISNT REALLY BARE ANYMORE.
BEST BET IS TO GO FOR ARND AN INCH...1 TO 2 INCH BAND IN THE ABV
DEFINED AREA. 2 TO 3 IN IN A NARROW BAND PSBLY AS WELL AS HIR POPS
BUT THIS MAY HAVE TO WAIT TILL WE CAN REFINE FCST FRTHR AS EVENT
GETS CLOSE. WEAK UPPER SUPPORT MAY BE DECEPTIVE WITH THE BETTR
LOW/MID LVL THERMAL SUPPORT WHICH CAN BE PRETTY EFFECIENT AT
SQUEEZING OUT WHAT MOISTURE THERE IS. SNOW SHUD TAPER OFF PRETTY
QUICKLY LATE TNGT. FOR NOW...NO HEADLINES ANTICIPATED BUT STAY TUNED
TDA.
WITH THE COLDER AIR GETTING QUICKLY INTO PLACE AND MOISTURE BCMG
PRIMARILY CONCENTRATED IN THE LWR LVLS...FLRYS SEEM BEST BET FOR WED
INTO THU...BUT WILL KEEP CHC LGT SNW MAINLY NERN FCST AREA LATE WED
AND WED NGT WITH ANOTHER WEAK IMPULSE MOVG ACRS AREA FROM THE NW.
LTL CHANGE IN FCST FOR FRI THRU TUE WITH SMALL POP MENTNS OF LGT SNW
FOR FRI/FRI NGT AND FOR SAT NGT/SUN PARTS OF FCST AREA. THESE DUE TO
A COMBO OF WEAK IMPULSES IN FLATTENING NWRLY FLOW AND A COUPLE BOUTS
OF WARM ADVECTN. THE COLD TEMPS FOR WED AND THU SHUD GNLY MODERATE A
LTL WITH FITS OF WARMNG AND COOLING AS THESE WEAK IMPLSES PASS AREA.
BUT FOR NOW...LOOKS LIKE THE BEST ROUND OF SNOW NEXT 7 DAYS MAY COME
TNGT.
AVIATION
VFR THRU 00Z THEN GRADUALLY BECOMING MVFR CIGS AND VSBYS DUE TO SNOW
AFTER 02Z. SNOW WL OCCUR BEHIND A CDFNT WHICH WILL SLIDE SEWD ACRS
THE REGION THIS AFTERNOON AND TONIGHT. VSBYS WL OCNLY DROP TO 1SM IN
SNOW MAINLY ALONG AND SOUTH OF INTERSTATE 90.
FSD WATCHES/WARNINGS/ADVISORIES
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
WILLIAMS
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