FXUS63 KABR 160211 AAA
AFDABR

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE ABERDEEN SD
811 PM CST TUE DEC 15 2009

.UPDATE...
NO CHANGES NECESSARY TO THE FORECAST AT THIS TIME.

&&
.PREV DISCUSSION...
.SHORT TERM...TONIGHT THROUGH WEDNESDAY NIGHT
THE MODELS SHOW A WARM FRONT MAKING ITS WAY ACROSS THE REGION
TONIGHT AND WEDNESDAY. THE PROBLEM WILL BE THE EXPANSIVE SNOW
COVER AND THE STRONG INVERSION THAT WILL SET UP AND BE DIFFICULT
TO BREAK WITH NOT MUCH FOR WINDS IN THE LOW LEVELS TO GENERATE
MUCH MIXING. TEMPERATURES HAVE NOT BEEN ABLE TO WARM UP MUCH TODAY
UNDER SURFACE HIGH PRESSURE RIDGING EAST IN THE CWA. THUS...WITH
LIGHT WINDS THIS EVENING AND ONLY SCT HIGH LEVEL
CLOUDS...TEMPERATURES SHOULD FALL OFF QUICKLY...ESPECIALLY EAST IN
THE CWA. COULD SEE AROUND 10 BELOW OR LOWER IN THE JAMES VALLY BY
LATE EVENING. OTHERWISE...THE INVERSION WILL STRENGTHEN TONIGHT
AS THE WARM FRONT PUSHES ACROSS THE AREA ALOFT. AFTER LOWS ARE
REACHED THIS EVENING...THE TEMPERATURES SHOULD REMAIN STEADY OR
RISE SOME BY MORNING. ALSO...EXPECT MORE MID AND HIGH LEVEL CLOUDS
TO MOVE IN FROM THE PACIFIC LATER TONIGHT HELPING TO HOLD
TEMPERATURES UP. ON WEDNESDAY...AGAIN IT WILL BE DIFFICULT FOR
SIGNIFICANT WARMING WITH LIGHT SOUTH WINDS AT THE SURFACE AND
A CONTINUED STRONG INVERSION...ESPECIALLY EAST IN THE CWA.
ALTHOUGH IT WILL BE MUCH WARMER THAN TODAY. LOWERED HIGHS SOME FOR
TUESDAY ACROSS THE AREA. THE WARMEST AIR WILL HAVE MOVED CLOSER
TO THE SURFACE ON WEDNESDAY NIGHT ALONG WITH MORE MID AND HIGH
LEVEL CLOUDS. THUS...DONT EXPECT AS MUCH A FALL OFF IN
TEMPERATURES ON WEDNESDAY NIGHT DESPITE CONTINUED LIGHT WINDS AT
THE SURFACE.

.LONG TERM...THURSDAY THROUGH TUESDAY

12Z EXTENDED GUIDANCE A BIT MORE CONSISTENT IN
TIMING/PLACEMENT...WITH MAIN FEATURE BEING A WEAK UPPER TROUGH
MOVING OVERHEAD THURSDAY/FRIDAY...FOLLOWED BY BRIEF RIDGING...AND
THEN A MORE POTENT NORTHWEST FLOW SHORTWAVE DIVING INTO THE
DAKOTAS SUNDAY/SUNDAY NIGHT. 

PROFILES SUGGEST SNOW REGIMES UNDER THE THURSDAY/FRIDAY UPPER
TROUGH WILL BE LIMITED MAINLY TO WESTERN SOUTH DAKOTA AND NORTH
CENTRAL MINNESOTA. MAJORITY OF ENSEMBLE MEMBERS KEEP US DRY...WITH
A FEW STRAGGLERS SUGGESTING LIGHT QPF. IN THE LEE OF THIS
SYSTEM...GUIDANCE CONTINUES TO SPIT OUT SOME LIGHT QPF...HOWEVER
PROFILES LACK MOISTURE/LIFT IN THE DENDRITIC GROWTH ZONE ACROSS
THE CWA. CLOUD COVER MAY BE ANOTHER ISSUE WITH A PERSISTENT
SATURATED LAYER FROM 1 TO 5 KFT AT -5C. THE ONLY OPPORTUNITY WOULD
BE FOR SOME LIGHT SEEDER-FEEDER DERIVED FLURRY ACTIVITY...BUT BOTH
THE GFS/ECMWF LIMIT THE AMOUNT OF MIX/HIGH CLOUDS OVER THE CWA.

NORTHWEST FLOW SHORTWAVE SUNDAY PROVIDES A BETTER OPPORTUNITY FOR
MEASURABLE SNOWFALL...BUT THERE REMAINS SOME TIMING/PLACEMENT
CONCERNS THIS FAR OUT. MODELS BEGIN TO DIVERGE RAPIDLY FOR THE
START OF NEXT WEEK...SO NOT MUCH TO ADD ABOUT THAT TIMEFRAME TO
THIS DISCUSSION.

AS FOR TEMPERATURES...NOT SEEING ANY ANOMALIES DURING THE
EXTENDED...WITH CLOUD COVER BEING MAIN FORCING MECHANISM OUTSIDE
OF DIURNAL HEATING. H85/925 TEMPERATURES +/- 0C EXPECTED GOING
INTO THE WEEKEND...WITH A 5 TO 10C DROP OFF FOR FRIDAY NIGHT.  

&&

.AVIATION...
VFR CONDITIONS ARE EXPECTED AT ALL TAF LOCATIONS THROUGH TONIGHT
AND WEDNESDAY MORNING. 

&&

.ABR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
&&

$$
UPDATE...WISE
SHORT TERM...MOHR
LONG TERM...CONNELLY
AVIATION...WISE

WEATHER.GOV/ABERDEEN