FXUS63 KABR 090235 AAA
AFDABR

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE ABERDEEN SD
835 PM CST TUE DEC 8 2009

.UPDATE...
OVERALL THE FORECAST IS PANNING OUT...JUST DECIDED TO DELAY THE
END TO THE SNOW A BIT. TEMPERATURES LOOK ON TRACK AND WILL LET THE
WINTER WEATHER AND WIND CHILL ADVISORIES RIDE THROUGH THE NIGHT.
UPDATES HAVE ALREADY BEEN ISSUED.  

&&
.PREV DISCUSSION...
.SHORT TERM...THROUGH THURSDAY NIGHT
MAIN FOCUS REMAINS ON THE SHORT TERM SINCE ONCE THIS SYSTEM
DEPARTS WILL SEE THE UPPER PATTERN REMAIN DOMINATED BY A BROAD
TROUGH...WHILE UNDERNEATH...MINOR ADVECTION BUT PRIMARILY
INFLUENCED BY THE ARCTIC HIGH.

CURRENTLY SEEING BETWEEN 1/2 AND 1 MILE VISIBILITY WITH SNOW
WIDESPREAD ACROSS THE CWA...HOWEVER WEBCAMS INDICATE MAINLY NON
DENDRITIC SNOW...WITH LOTS OF BLOWING AND DRIFTING AND VERY LITTLE
ACTUAL ACCUMULATION. LOCAL WRF INDICATING A DROP OFF IN INTENSITY
ACROSS CENTRAL SD COUNTIES LATE THIS AFTERNOON...WHILE HIGHER
ACCUMULATION POTENTIAL STILL POSSIBLE FOR EASTERN COUNTIES. WEAK
SURFACE HIGH SLOWLY BUILDS SOUTH OF CWA WEDNESDAY...AND WHILE
THERMAL ADVECTION AND PRESSURE RISES ARE WEAK...PRESSURE GRADIENT
ACROSS THE EASTERN CWA STRONG ENOUGH TO SUPPORT GUSTY NORTH WINDS.
WITH H925 TEMPERATURES TO -20C...ANTICIPATE LOW END WIND CHILL
ADVISORY CRITERIA MET FOR ENTIRE CWA. GRADIENT SLACKENS BETWEEN 12Z
AND 00Z SO A GRADUAL TRANSITION FOR LIGHTER WINDS FROM WEST TO
EAST FOR WEDNESDAY AFTERNOON. LACKING SIGNIFICANT HIGH PRESSURE TO
FOLLOW SYSTEM...ALSO WILL RETAIN LOW CLOUDS THROUGH MUCH OF THE
FORECAST PERIOD.
 
.LONG TERM...FRIDAY THROUGH TUESDAY
MAIN CONCERN IN THE LONG TERM PERIOD WILL BE TEMPERATURES...WITH
LITTLE IN THE WAY OF SIGNIFICANT PRECIPITATION EXPECTED. HIGH
PRESSURE WILL BE DOMINANT OVER THE REGION DURING THE DAY FRIDAY.
AN ARCTIC FRONT WILL APPROACH THE REGION FRIDAY NIGHT AND LOOKS TO
TRACK ACROSS THE CWA LATE FRIDAY NIGHT/EARLY SATURDAY MORNING.
ANOTHER SURGE OF COLD AIR WILL FOLLOW THIS FRONT...WITH HIGH
PRESSURE BECOMING CENTERED OVER THE EASTERN DAKOTAS/MINNESOTA BY
SUNDAY MORNING. EXPECT COLDEST TEMPERATURES TO BE OVER THE
EASTERN CWA WHERE THERE WILL SOME SNOW COVER. THE MAIN HIGH CENTER
PUSHES EAST ON SUNDAY...BUT ELONGATED HIGH PRESSURE WILL REMAIN IN
PLACE FROM SASK TO THE OHIO VALLEY. MAY SEE A LITTLE LIGHT SNOW
TRACK ACROSS THE REGION SUNDAY AND SUNDAY NIGHT AS A WEAK SURFACE
TROUGH TRACKS ACROSS THE PLAINS...BUT AT THIS TIME TO NOT EXPECT
ANY SIGNIFICANT AMOUNTS AS THE IT WILL BE A FAST MOVING SYSTEM.
HIGH PRESSURE DROPS BACK OVER THE PLAINS ON MONDAY...AND MAY
RESULT IN ANOTHER SURGE OF COLD AIR. HAVE KEPT TEMPERATURES UP
SOME LATE IN THE PERIOD FOR NOW...BUT THIS MAY NEED TO BE WATCHED
CLOSELY FOR A POSSIBLE LOWERING OF TEMPERATURES TUESDAY.

&&

.AVIATION...
A MIX OF MVFR/IFR CIGS/VSBYS WILL CONTINUE AT ALL SITES THROUGH AT
LEAST MIDNIGHT. THEN A SLOW AND GRADUAL END SHOULD COME TO THE SNOW
FROM THE WEST LATE. VFR CONDITIONS SHOULD GRADUALLY OVERSPREAD THE
AREA ON WEDNESDAY MORNING.  

&&

.ABR WATCHES/WARNINGS/ADVISORIES...
SD...WIND CHILL ADVISORY UNTIL 3 PM CST /2 PM MST/ WEDNESDAY 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.

     WINTER WEATHER ADVISORY UNTIL 6 AM CST WEDNESDAY FOR BUFFALO-
     CLARK-CODINGTON-DEUEL-GRANT-HAMLIN-HAND-HYDE-JONES-LYMAN-
     SPINK.

MN...WIND CHILL ADVISORY UNTIL 3 PM CST WEDNESDAY FOR BIG STONE-
     TRAVERSE.

     WINTER WEATHER ADVISORY UNTIL 6 AM CST WEDNESDAY FOR BIG STONE.

&&

$$
UPDATE...TDK
SHORT TERM...CONNELLY
LONG TERM...PARKIN
AVIATION...TDK

WEATHER.GOV/ABERDEEN