FXUS63 KMPX 252241
AFDMPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
441 PM CST FRI DEC 25 2009

.UPDATE...
UPDATED TO INCLUDE 00Z AVIATION DISCUSSION BELOW.

&&

.DISCUSSION...

MESSY AND VERY COMPLICATED STORM SYSTEM LOSING IT MAIN PUNCH...BUT
WILL CONTINUE TO IMPACT THE AREA FOR ANOTHER 24 HOURS OR SO.
TRIMMED BACK THE HEADLINES SOMEWHAT LATE THIS MORNING IN EASTERN
CWA...AND HAVE CUT BACK ON MORE HEADLINES WITH THIS ISSUANCE.

SURFACE LOW HAS BEEN TRACKING STEADILY NW ACROSS IOWA TODAY 
AND IS NOW NEAR FORT DODGE. IT HAS MAINTAINED A CENTRAL PRESSURE
OF 987 MB. WITH PRESSURE FALLS STILL WEST OF SFC LOW IT WILL
PROBABLY TRACK A BIT FARTHER WEST BEFORE UPPER LOW PULLS IT BACK
EAST. VERY WELL DEFINED VIGOROUS VORT MAX WHICH ROTATED AROUND
UPPER LOW IS NOW NEAR ST. JAMES AND CONTINUING TO PUSH WNW.
ANOTHER WEAKER VORT PUSHING ACROSS ILLINOIS IS EXPANDING ANOTHER
AREA OF PRECIP ACROSS SW WI WHICH WILL SPREAD INTO CWA LATER THIS
EVENING. WARM WEDGE OF AIR ACROSS WC WI INTO E MN WHICH HAS
PESTERED US WITH A MIX WILL DISAPPEAR THIS EVENING AS COOLER AIR
WRAPS IN FROM THE SOUTH. SURFACE TEMPS IN NE IA HAVE FALLEN FROM
THE MID 30S INTO THE UPPER 20S LAST COUPLE OF HOURS. WE MAINTAIN
SOME WEAK BUT PERSISTENT ISENTROPIC LIFT OVERNIGHT ACROSS N INTO
WC MN. THIS MAY PRODUCE ANOTHER 2-4 INCHES OF SNOW...THUS WILL
MAINTAIN THE WARNING IN WC MN. WINDS GUSTING TO 25 TO 30 MPH WILL
ALSO PRODUCE SOME BLOWING OR DRIFTING NEAR THE DAKOTAS BORDER. 
DOWNGRADED TO AN ADVISORY OVERNIGHT FOR A SWATH OF COUNTIES ACROSS
CENTRAL INTO SC MN FOR 1-3 INCHES SNOW...AND REMOVED HEADLINES
FROM THE TC METRO TO AEL THEN EWRD ACRS WC WI. MAY SEE AN INCH OR
SO ACCUMULATE OVERNIGHT.

-SN WILL CONTINUE ACROSS AREA OF SATURDAY/SATURDAY NIGHT AS LOW
FILLS AND WOBBLES AROUND WISCONSIN. RATHER UNUSUAL TEMPERATURE
FORECAST NEXT 24 HOURS WITH COLDEST AIR NEAR THE CORE OF LOW
PRESSURE...SO TONIGHT'S MINS AND TOMORROWS MAX TEMPS COOLEST IN SE
MN INTO WI. 

WITH A FORMIDABLE SNOW PACK ACROSS THE AREA TEMPERATURES COULD
TUMBLE...BUT WILL WILL MAINTAIN MOSTLY CLOUDY SKIES NEXT FEW DAYS
WHICH WILL LIMIT FALLS. 

WEAK FAST MOVING SHORTWAVES MOVING ACROSS AREA WED/THURS WILL
BRING CHC -SN...MAINLY TO NE CWA. 

&&

.AVIATION.../00Z TAF ISSUANCE/ 
SURFACE LOW IS CURRENTLY BEGINNING TO FILL OVER NORTHWEST IOWA AS
UPPER LOW SPINS ABOVE IN THE GENERAL VICINITY. SEVERAL LOBES OF
VORTICITY CONTINUE TO ROTATE AROUND THE UPPER LOW... HELPING TO
SPUR SPOKES OF ENHANCE PCPN AS SEEN ON RADAR IMAGERY. ONE OF THESE
IS CURRENTLY MOVING INTO THE AREA FROM THE SOUTHEAST AND WILL
SWING ACROSS DURING THE FIRST PART OF THE FORECAST AREA. SURFACE
TEMPERATURES REMAIN FAIRLY WARM AHEAD OF IT AND MOST OBSERVATIONS
HAVE BEEN IN THE LIQUID FORM... SO WILL INITIALLY INCLUDE A RASN
MENTION AS THIS PCPN MOVES IN... WITH A CHANGE TO SN AND
CORRESPONDINGLY LOWER VISIBILITIES AS IT MIGRATES WESTWARD.

KMSP... PRIMARY UNCERTAINTIES IN TAF ARE WITH PCPN TYPE INITIALLY
AS ACTIVITY ARRIVES FROM THE SOUTHEAST. ALSO SOME QUESTION ON
CEILINGS AND VISIBILITIES... BUT WILL PLAY THINGS ON THE MORE
OPTIMISTIC SIDE AT THIS POINT GIVEN UPSTREAM OBSERVATIONS AND
OVERALL WEAKNESS OF ENCROACHING REFLECTIVITIES ON RADAR.

&&

.MPX WATCHES/WARNINGS/ADVISORIES...
MN...WINTER STORM WARNING UNTIL 6 AM CST SATURDAY FOR CHIPPEWA-
     DOUGLAS-LAC QUI PARLE-POPE-REDWOOD-STEVENS-SWIFT-TODD-
     YELLOW MEDICINE.

     WINTER WEATHER ADVISORY UNTIL 6 AM CST SATURDAY FOR BENTON-BLUE 
     EARTH-BROWN-FARIBAULT-ISANTI-KANABEC-KANDIYOHI-MARTIN-
     MCLEOD-MEEKER-MILLE LACS-MORRISON-NICOLLET-RENVILLE-
     SHERBURNE-SIBLEY-STEARNS-WATONWAN-WRIGHT.

WI...NONE.
&&

$$

BAP/TRH