FXUS63 KARX 260922
AFDARX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
322 AM CST THU NOV 26 2009

.SHORT TERM...TODAY THROUGH SATURDAY

THE MAIN CONCERNS FOR THIS PERIOD IS PRECIPITATION THIS MORNING...
AND CLOUD COVER FROM TODAY THROUGH FRIDAY.

AT 3 AM...A SURFACE LOW WAS LOCATED NEAR MILWAUKEE. WEST OF THIS
LOW...AREAS OF RAIN AND SNOW CONTINUE TO MOVE SOUTHWARD ACROSS
WESTERN WISCONSIN...AND PARTS OF SOUTHEAST MINNESOTA AND NORTHEAST
IOWA. OTHER THAN A RARE HUNDREDTH PER HOUR...THIS PRECIPITATION 
IS NOT MEASURING. CURRENT THOUGHTS IS THAT THE PRECIPITATION
SHOULD MOVE OUT OF THE AREA BY 6 AM...SO THERE ARE NO PLANS ON
ADDING THESE TO THE ZONE FORECASTS. WE WILL HANDLING THIS THROUGH
SHORT TERM FORECASTS.

THE MAIN FORECAST CONCERN FOR TODAY IS WHEN THE CLOUDS WILL MOVE
OUT OF THE FORECAST AREA. THE 26.00Z 925 MB MOISTURE IS DRYING OUT
TOO FAST IN THE NAM/WRF. OVERALL IT APPEARS THAT THE GFS SEEMS A
BIT MORE REALISTIC...AND THE CLEARING WAS DELAYED SOME. AT THIS 
TIME...IT LOOKS LIKE THE CLOUDS WILL BEGIN CLEAR OUT IN SOUTHEAST
MINNESOTA...NORTH CENTRAL WISCONSIN...AND NORTHEAST IOWA BETWEEN
11 AM AND 3 PM...AND THE REMAINDER OF THE AREA BETWEEN 2 PM AND 
6 PM.

THE MID AND HIGH CLOUDS WILL INCREASE ACROSS THE AREA TONIGHT AND
THEN LINGER INTO FRIDAY MORNING. THIS IS ASSOCIATED WITH WARM AIR
ADVECTION AND MOISTURE CONVERGENCE AHEAD OF A POSITIVE VORTICITY 
MAXIMUM MOVING SOUTHEAST THROUGH REGION. AS A RESULT...THE CLOUD
FORECAST FOR THESE TIME PERIODS WAS ADJUSTED TO PARTLY CLOUDY.

.LONG TERM...SATURDAY NIGHT THROUGH WEDNESDAY

THE MODELS CONTINUE TO SHOW THAT A LONG WAVE TROUGH WILL MOVE
SOUTHEAST THROUGH THE REGION ON SUNDAY. THE 26.00Z GFS DOES NOT
GENERATE PRECIPITATION UNTIL IT GETS SOUTHEAST OF THE FORECAST
AREA. MEANWHILE THE ECMWF GENERATES SOME LIGHT PRECIPITATION
ACROSS THE FORECAST ARE ON SATURDAY NIGHT. WITH VERY LITTLE RUN TO
RUN CONSISTENCY AND ALREADY SLIGHT CHANCES /20 PERCENT/ IN THE
FORECAST GRIDS...NO CHANGES WERE MADE TO THIS PERIOD.

&&

.AVIATION...TODAY THROUGH SATURDAY

-RA/SN HAS MOVED OFF TO THE EAST OF THE TAF SITES...LEAVING A SHIELD 
OF MVFR //2 KFT// CEILINGS TO DEAL WITH. MODEL/S RH FIELDS NOT 
HANDING THE EXTENT OF THE LOW CLOUD VERY WELL...WITH THE GFS 925 MB 
REPRESENTATION PROBABLY DOING THE BEST. THE FOG/STRATUS SATELLITE 
IMAGERY PLACES THE WESTERN EDGE INTO EASTERN SECTIONS OF THE 
DAKOTAS...JUST EAST OF THE SFC RIDGE. THERE WERE NO VSBY 
RESTRICTIONS ASSOCIATED WITH THE CLOUDS. 

SUBSIDENCE AND MIXING COULD WORK TO ERODE THE WESTERN EDGES OF THE 
CLOUD SHIELD DURING THE DAY...ALTHOUGH BUFKIT SOUNDINGS HOLD ONTO 
AT LEAST A WEAK INVERSION AROUND 875 MB. BELIEVE THE CLEARING WILL 
BE MORE CO-LOCATED WITH THIS RIDGE AXIS...AND WILL USE THIS FOR 
TIMING. SOME MID CLOUDS COULD RETURN VIA WARM AIR ADVECTION ACROSS 
THE RIDGE FOR TONIGHT INTO FRIDAY...BUT CONDITIONS SHOULD BE VFR 
INTO SATURDAY...AFTER THE MVFR CLOUD SHIELD CLEARS TODAY. 

&&

.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&

$$

SHORT/LONG TERM...BOYNE
AVIATION...RIECK