FXUS63 KABR 260224
AFDABR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ABERDEEN SD
824 PM CST FRI DEC 25 2009

.UPDATE...
CURRENT FORECAST IS DOING WELL. RADAR SHOWS WIDESPREAD AREAS OF
SNOWFALL WITH VERY STRONG NORTH WINDS REDUCING VISIBILITY.
TEMPERATURE ARE WELL HANDLED IN THE GOING GRIDS. JUST MADE A FEW
MINOR CHANGES TO RATE OF FALL BUT OVERNIGHT LOW LOOKS GOOD. NO
UPDATE IS PLANNED AT THIS TIME.

&&
.PREV DISCUSSION...
.SHORT TERM...TONIGHT THROUGH SUNDAY NIGHT

AS EXPECTED BLIZZARD CONDITIONS ARE PREVALENT ACROSS THE CWA
ESPECIALLY THE JAMES VALLEY WEST. THE FEW COUNTIES THAT HAVE YET
TO VERIFY DUE TO LOWER WIND SPEEDS WILL MOST LIKELY MAKE UP FOR
THAT TONIGHT AND SATURDAY MORNING AS THE LOW BEGINS TO WOBBLE EAST.

CURRENTLY THE VERY TIGHTLY WRAPPED LOW IS OVER NORTHERN IOWA.
THERE IS A SIGNIFICANT SURFACE THERMAL GRADIENT AROUND THE CENTER
OF THE LOW WITH UPPER 30S AND EVEN LOWER 40S ON THE NE SIDE INTO
IA AND MN...UPPER 20S TO MID 30S ON THE NW SIDE IN WEST CENTRAL MN
AND EASTERN SD UNDER THE TROWAL...AND TEENS TO THE SW IN NE. THERE
ARE BRIEF BREAKS IN THE BANDS OF SNOW AROUND THE LOW BUT SNOW HAS
BEEN FALLING HEAVILY WITHIN THE BANDS ESPECIALLY OVER EASTERN SD
AND WEST CENTRAL MN. REPORTS THIS MORNING INDICATED SNOW RATIOS OF
15 OR 20:1 EVEN WITH THE WARMER TEMPS AND STRONG WINDS. THEREFORE
DECIDED TO INCREASE SNOW AMOUNTS AND STORM TOTAL SNOW AMOUNTS TO
12 TO 18 INCHES ACROSS THE CWA. WITH THE DRIFTING AND BLOWING SNOW
THIS WILL BE DIFFICULT TO VERIFY EITHER WAY.

OTHERWISE THE FORECAST LOOKS TO BE ON TRACK WITH THE BRUNT OF THE
SYSTEM MOVING OUT BY SATURDAY EVENING AND SNOW SHOWERS TAPERING
OFF FROM WEST TO EAST BY SUNDAY AFTERNOON.

.LONG TERM...MONDAY THROUGH THURSDAY
PERIOD LOOKS RATHER QUIET WITH MOSTLY DRY CONDITIONS. AT THE START
OF THE PERIOD AN UPPER LEVEL RIDGE WILL BE OVER THE AREA WITH A
HIGH AT THE SFC. THE WARMER AIR ALOFT WILL NOT BE FELT AT THE SFC
THOUGH AS A FRESH DEEP SNOW PACK AND WEAK MIXING FROM THE HIGH
WILL KEEP TEMPS COLD. MODELS SHOW A WEAK SHORTWAVE MOVING THROUGH
THE AREA TUESDAY NIGHT BUT WITH VERY LITTLE MOISTURE TO WORK WITH.
WILL LEAVE FORECAST DRY AT THIS TIME. UPPER FLOW THEN TURNS
NORTHWESTERLY WITH COLDER AIR WORKING SOUTH OUT OF CANADA.
CONTINUED THE TREND OF GOING BELOW MEX GUIDANCE FOR HIGH
TEMPERATURES THROUGHOUT THE EXTENDED DUE TO THE EXPECTED DEEP SNOW
PACK WHICH WILL BE ACROSS THE ENTIRE UPPER MIDWEST.

&&

.AVIATION...
WIDESPREAD IFR CONDITIONS ARE COVERING THE REGION TONIGHT.
VISIBILITY AS LOW AS 1/4 MILE ARE BEING REPORTED AT TIMES. THE
REST OF TONIGHT IF CONDITIONS WILL CONTINUE WITH SNOW AND BLOWING
SNOW AND HIGH WINDS. TOMORROW WILL SEE A GRADUAL IMPROVEMENT
ESPECIALLY AFTER NOON.

&&

.ABR WATCHES/WARNINGS/ADVISORIES...
SD...BLIZZARD WARNING UNTIL NOON CST /11 AM MST/ SATURDAY FOR BROWN-
     BUFFALO-CAMPBELL-CLARK-CODINGTON-CORSON-DAY-DEUEL-DEWEY-
     EDMUNDS-FAULK-GRANT-HAMLIN-HAND-HUGHES-HYDE-JONES-LYMAN-
     MARSHALL-MCPHERSON-POTTER-ROBERTS-SPINK-STANLEY-SULLY-
     WALWORTH.

MN...BLIZZARD WARNING UNTIL NOON CST SATURDAY FOR BIG STONE-TRAVERSE.

&&

$$
UPDATE...KEEFE
SHORT TERM...WISE
LONG TERM...TMT
AVIATION...KEEFE

WEATHER.GOV/ABERDEEN