FXUS63 KFSD 262154
AFDFSD
AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NATIONAL WEATHER SERVICE SIOUX FALLS SD
355 PM CST SAT DEC 26 2009
.DISCUSSION...
VISIBILITIES CONT TO MIGRATE SLOWLY UPWARD. SOME OF THIS MAY BE
THE TENDENCY FOR THESE BANDS OF SNOW MOVG SWD OVER AREA TO DCRS IN
INTENSITY...BUT ERYR WE GOT REPORTS OF HIER VSBYS WITHOUT THAT
FACTOR. SOME OF THE EVR DRIFTING WE WERE GETTING REPORTS OF ERYR
ARE DOUBTLESS CONTG. ALSO...JUST IN THE LAST HR THE WINDS HAVE MOVED
INTO MML AREA AS EXPECTED...SO ADDING THAT LTL CHUNK OF SWRN MN TO
THE ADVY LOOKS GOOD. FRTHR E OVER FAR ERN FCST AREA...WNDS ARE STILL
LGT SO NO ADVY NEEDED WITH JUST SOME LGT SNOW. SO...THE MAIN QSTN IS
DO WE KEEP THE ADVY JUST TILL 6PM AS WE HAVE IT NOW...OR DO WE
EXTEND IT A LTL LATER INTO THE EVE. ANTICIPATION OF FRTHR SLOW DCRS
IN WNDS AND DISCUSSION WITH ADJOINING OFFICES/AREAS SUGGEST KEEPIING
THE 6 PM CST ENDING TIME AND WILL DO THAT. LIMITED DRIFTING WILL
CONT BEYOND THAT TIME. WILL KEEP AREAS OF BLOWING SNOW FOR ERY THIS
EVE...THO AS MENTND IT IS REALLY MORE OF A DRIFTING PRBLM.
THE LGT SNOW SHUD CONT TO VERY SLOWLY WANE. WILL KEEP LIKELY POPS
FOR THIS EVE AND CHC POPS FOR LATE TNGT...WITH NEW ACCUM LESS THAN
AN INCH. CLOUDS SHUD STAY IN WITH BREAKS E OF FCST AREA PRBLY NOT
QUITE MAKING IT INTO ERN MN/IA ZNS. TEMPS WILL ONLY SLOWLY COOL WITH
LOWS IN THE DOUBLE FIGURES...MOSTLY IN THE 10 TO 15 RANGE. WNDS WILL
CONT TO VERY SLOWLY ABATE. / WILLIAMS
PRETTY MUCH STATUS QUO ON THE FCST FM SUN THRU NEXT SAT...WITH THE
MAIN CANADIAN COLD SURGE EXPCD THURS INTO SAT. IN THE MEANTIME...
CLOUDS AND FLUR FOR SUN...WITH STILL A TENTH OR TWO SNOWFALL PSBL...
THEN SUBSIDENCE AND CLEARING FM NW TO SE SUN NGT. BRISK NWLY
GRADIENT OFF THE SFC SHOULD KEEP TEMPS FROM DROPPING TOO FAR EVEN
WITH THE TONS OF FRESH SNOW COVER. THEN SFC HIGH MOVES SEWD OVER
CWA MON NGT. EVEN THOUGH MAIN COLD ADVECTION INTO MINNESOTA...GOOD
RADIATIONAL COOLING CONDITIONS WILL PERMIT TEMPS TO DROP BELOW ZERO
OVER PRISTINE SNOW. RETURN SLY FLOW AND WARM ADVECTION MOVES EWD
OVER CWA AHEAD OF WEAK SHORT WAVE TUES...LEADING TO A SMALL CHC -SN
SERN CWA TUE NGT INTO EARLY WED. WED A FAIRLY MILD TRANSITION DAY
AHEAD OF COLDER AIR SPILLING OUT OF CANADA FOR THU INTO SAT...SO
WENT ON THE COLD SIDE OF GUIDANCE FOR THIS PERIOD. IF YOU REALLY
WANT TO GET OUT THERE LOOKING FOR THE NEXT SYSTEM...THE 12Z ECMWF
AND GFS IMPLY SOMETHING JAN 5/6TH OR THEREABOUTS. /RYRHOLM
&&
.AVIATION...
GNLY MVFR CIGS 1-3K FT WILL CONT OVER AREA THRU 27/18Z. A FEW
LCL AREAS OF CIGS JUS BLO 1K FT...DOWN TO 7-8 HND FT...PSBL THRU
27/12Z MAINLY IN SWRN MN AREA. VSBYS WILL BE MORE VRBL WITH VFR TO
MVFR VSBYS AND LGT SNOW BANDS MOVE THRU...WITH AREAS OF 1-3SM IN
-SN. DURG 127/12Z-18Z PD VSBYS SHUD IMPROVE TO GNLY VFR WITH A FEW
AREAS OF 3-5SM IN LGT SNOW. AFT 27/ ST/SC SHUD BEGIN TO BREAK
UP...PRBLY FROM THE W AS CLEARING THREATENING ERN EDGE OF FCST AREA
RECEDES. VSBYS SHUD BE VFR AFTER 27/18Z. / WILLIAMS
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
IA...WINTER WEATHER ADVISORY UNTIL 6 PM CST THIS EVENING FOR IAZ001-
012-020-031.
MN...WINTER WEATHER ADVISORY UNTIL 6 PM CST THIS EVENING FOR MNZ071-
072-097-098.
NE...WINTER WEATHER ADVISORY UNTIL 6 PM CST THIS EVENING FOR NEZ013-
014.
SD...WINTER WEATHER ADVISORY UNTIL 6 PM CST THIS EVENING FOR SDZ038>
040=050-052>071.
&&
$$
