FXUS63 KABR 142131
AFDABR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ABERDEEN SD
331 PM CST MON DEC 14 2009

.SHORT TERM...TONIGHT THROUGH WEDNESDAY NIGHT
THE MODELS AND ENSEMBLES CONTINUE TO AGREE WELL AND BE CONSISTENT
THROUGH THE SHORT TERM. A SHORT WAVE TROUGH WILL BE DROPPING
ACROSS ND THROUGH THE EVENING SPREADING SOME MORE MID LEVEL CLOUDS
ACROSS OUR CWA THIS EVENING WITH IT CLEARING QUICKLY BEHIND IT IN
THE SUBSIDENT AREA. ADDED IN A SLIGHT CHANCE OF LIGHT SNOW ACROSS
MUCH OF NORTH CENTRAL SOUTH DAKOTA FOR THIS EVENING. OTHERWISE...SURFACE
HIGH PRESSURE RIDGING WILL BUILD INTO THE CWA AND BE CENTERED MORE
ACROSS THE WESTERN CWA TONIGHT. THUS...WINDS ACROSS MUCH OF THE
CWA SHOULD STAY UP IN THE 5 TO 10 MPH RANGE...ESPECIALLY ACROSS
THE EASTERN CWA THROUGH THE NIGHT. WITH THE NEW SNOW COVER AND
CLEARING SKIES...EXPECT TEMPERATURES TO FALL OFF QUICKLY THIS
EVENING. EXPECT WIND CHILLS TO FALL INTO THE ADVISORY RANGE ALSO
THIS EVENING ACROSS MUCH OF THE CWA. THUS...WILL ISSUE A WIND
CHILL ADVISORY FOR MUCH OF THE CWA. ON TUESDAY...THE SURFACE HIGH
PRESSURE RIDGE WILL BUILD EAST AND OUT OF THE STATE BY EVENING
WITH THE LIGHT AND VARIABLE WINDS IN THE MORNING TURNING TO THE
SOUTH TO SOUTHEAST. DESPITE HAVING MOSTLY SUNNY
SKIES...TEMPERATURES WILL BE VERY SLOW TO RISE FROM THE BITTER
COLD OVERNIGHT LOWS. SOUTH WINDS WILL NOT HELP MUCH OVER THE
WIDESPREAD SNOW COVER. THUS...EXPECT TEMPERATURES TO JUST RISE
INTO THE ZERO TO 10 DEGREE RANGE BY LATE AFTERNOON WITH SOME
PLACES IN THE NORTHEAST CWA MAYBE NOT MAKING IT TO ZERO. THE
MODELS AND ENSEMBLES CONTINUE TO SHOW 50H HEIGHTS RISING OVER THE
REGION FOR WEDNESDAY AND THURSDAY. THUS...EXPECT A WARM UP FOR
WEDNESDAY BUT NOT QUITE AS MUCH AS COULD OCCUR AS RESULT OF THE
SNOW COVER...LOW SUN ANGLE AND LACK OF GOOD MIXING IN THE LOW
LEVELS. EXPECT TEMPERATURES TO FALL OFF QUICKLY TUESDAY EVENING
AND THEN LEVEL OFF THROUGH THE NIGHT AS SOUTH WINDS PICK UP A
LITTLE. OTHERWISE...WEDNESDAY WILL BE WARMER ACROSS THE
CWA...ESPECIALLY OUT WEST. WILL ALSO KEEP IT DRY FOR TUESDAY
THROUGH WEDNESDAY NIGHT.

.LONG TERM...THURSDAY THROUGH MONDAY
DETERMINISTIC MODELS...ALONG WITH ENSEMBLE MEANS AGREE FAIRLY WELL
WITH THE EVOLUTION OF THE LONGWAVE FLOW PATTERN IN THE EXTENDED.

THE PERIOD OPENS WITH THE FLOW PATTERN TRANSITIONING FROM NEARLY
ZONAL...TO NORTHWEST FLOW OVER THE NORTHERN PLAINS. A SHORT WAVE
THAT PASSES THROUGH THE REGION THURSDAY NIGHT...WILL CURVE OUT AN
EAST COAST TROF. THIS EAST COAST TROF...ALONG WITH A DEEPER EAST
PACIFIC TROF...WILL LEAD TO AN AMPLIFIED RIDGE OVER THE ROCKY
MOUNTAINS. THIS PATTERN WILL LIKELY REMAIN IN PLACE FROM SATURDAY
THROUGH THE END OF THE PERIOD. BELIEVE HIGHS THIS WEEKEND MAY BE
TOO WARM BASED ON MODELS SHOWING A STRONG EAST CANADIAN LOW
PRESSURE...RETROGRADING INTO THE GREAT LAKES REGION. DEPENDING ON
THE WESTWARD EXPANSION OF THIS SYSTEM...TEMPERATURES COULD BE
SIGNIFICANTLY COLDER. BOTH THE GFS/ECMWF SHOW MORE OF A GLANCING
BLOW WITH THE COLD AIRMASS...WITH THE EASTERN HALF OF THE CWA
SEEING HIGHS BY SUNDAY IN THE LOW TEENS. AN INTERESTING
NOTE...EVEN THOUGH THE AIRMASS THIS WEEKEND WILL ORIGINATE FROM
THE HUDSON BAY REGION...H925 TEMPERATURES ONLY FALL TO 15 BELOW AT
BEST.

AS FOR PRECIPITATION CHANCES...THE INHERITED GRIDS HAD SNOW FOR
THURSDAY NIGHT THROUGH FRIDAY NIGHT. WILL LEAVE THE MENTION OF
LIGHT SNOW FOR NOW...EVEN THOUGH CONFIDENCE OF SEEING MEASURABLE
PRECIP IS LOW.

&&

.AVIATION...
EXPECT PREVAILING VFR CONDITIONS THROUGH TUESDAY AS A HIGH
PRESSURE BUILDS INTO THE AREA. SCATTERED SNOW FLURRIES MAY BE
POSSIBLE AT TIMES THIS EVENING FOR THE KPIR AND KMBG TERMINAL.
VISIBILITIES MAY BRIEFLY FALL TO MVFR RANGE WITH SOME HEAVIER
BANDS OF SNOW.

&&

.ABR WATCHES/WARNINGS/ADVISORIES...
SD...WIND CHILL ADVISORY UNTIL NOON CST /11 AM MST/ TUESDAY FOR BROWN-
     BUFFALO-CAMPBELL-CLARK-CODINGTON-CORSON-DAY-DEUEL-DEWEY-
     EDMUNDS-FAULK-GRANT-HAMLIN-HAND-HUGHES-HYDE-MARSHALL-
     MCPHERSON-POTTER-ROBERTS-SPINK-SULLY-WALWORTH.

MN...WIND CHILL ADVISORY UNTIL NOON CST TUESDAY FOR BIG STONE-
     TRAVERSE.

&&

$$
SHORT TERM...MOHR
LONG TERM...SD
AVIATION...SD

WEATHER.GOV/ABERDEEN