000
FXUS63 KARX 040503
AFDARX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
1100 PM CST TUE DEC 3 2013

.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 327 PM CST TUE DEC 3 2013

BUSY DAY ACROSS THE AREA WITH SEVERAL WEATHER THREATS IN THE SHORT
TERM...FROM FOG TO SNOW AND FREEZING RAIN POTENTIAL.

20Z SURFACE ANALYSIS SHOWS LOW PRESSURE CENTERED NEAR KANSAS
CITY...WITH AN INVERTED TROUGH REACHING NORTH INTO MN...AND A WARM
FRONT REACHING EAST TO NORTHERN IL. LARGE AREA OF WARM AND MOIST
AIR AHEAD OF THE SYSTEM...AND WITH GENERALLY WEAK WIND FLOW...
DENSE FOG HAS BECOME WIDESPREAD. THERE WAS SOME IMPROVEMENT IN
VISIBILITY FOR A FEW SPOTS TODAY...BUT WITH SUNSET IT IS EXPECTED
THAT FOG WILL QUICKLY THICKEN ONCE AGAIN. HENCE...DENSE FOG
ADVISORY WAS EXTENDED OUT THROUGH NOON TOMORROW EARLIER IN THE
DAY...AND AFTER COORDINATION WITH MKX...HAVE EXPANDED IT NORTH TO
INCLUDE AREAS FROM BLACK RIVER FALLS OVER TO NECEDAH/FRIENDSHIP.

CURRENT BAND OF PRECIPITATION...RAIN OVER IA/SOUTHERN WI AND SNOW
OVER SOUTHEAST MN INTO WESTERN/CENTRAL WI...IS PUSHING EASTWARD
AS A WEAK SHORT WAVE TROUGH SEEN IN WATER VAPOR IMAGERY MOVES
THROUGH. EXPECT THIS TO BE GONE EARLY THIS EVENING AND THEN THERE
WILL BE A BREAK FOR A SHORT PERIOD OF TIME BEFORE THE NEXT ROUND
ARRIVES LATER TONIGHT. CLOSED CIRCULATION ALOFT OVER MT/WY
EXPECTED TO EJECT EAST AND THEN NORTHEAST BY WED. AS IT DOES SO...
SURFACE LOW WILL INTENSIFY ACROSS KS TONIGHT AND WILL SURGE
NORTHEAST TO NEAR GREEN BAY BY WED AFTERNOON. THIS TRACK WILL KEEP
THE AREA IN THE WEAK WIND FLOW WITH THE TROUGH HANGING TOUGH UNTIL
THE LOW MOVES THROUGH. MEANWHILE THE SUPPLY OF MILD AND MOIST AIR
WILL CONTINUE TO FEED IN. AS THE LOW DEEPENS AND THE TROUGH
EJECTS...EXPECT A NICE BAND OF WARM CONVEYOR BELT AND ISENTROPIC
UPGLIDE TO FEED THE DEFORMATION. THE FOCUS FOR THE HIGHEST SNOW
AMOUNTS WILL BE JUST TO THE NORTHWEST OF THE FORECAST AREA.
MAIN CHANGES TO THE FORECAST GRIDS TODAY WERE TO THE TEMPERATURE
PROFILES. ALL MODELS WERE TRENDING FOR WARMER TEMPERATURES IN THE
WARM FEED AHEAD OF THE SYSTEM...SO TRENDED THAT WAY AS WELL. THIS
LEAD TO SLIGHTLY LESS SNOW AND LESS OF A MIX. HOWEVER TEMPERATURE
PROFILES STILL LOOK TO BE SUCH THAT A WINTRY MIX WILL BE POSSIBLE
AT LEAST FOR A TIME FROM PARTS OF SOUTHEAST MN INTO NORTH CENTRAL
WI. THE LONGEST PERIOD OF MIXED PRECIP AND SNOW WILL BE OVER THE
CLARK/TAYLOR AREA AND WILL CONTINUE THE WINTER WEATHER ADVISORY
FOR THIS AREA.

.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 327 PM CST TUE DEC 3 2013

COLD AIR WILL SURGE IN BEHIND THE DEPARTING SYSTEM ON BRISK WEST
TO NORTHWEST WINDS. TEMPERATURES WILL NOSE-DIVE INTO THE TEENS
WEDNESDAY NIGHT...AND WILL STRUGGLE TO RISE MUCH AT ALL ON
THURSDAY. BRISK NORTHWEST WINDS WILL ADD A FURTHER CHILL TO THE
AIR...WITH WIND CHILLS ONLY IN THE SINGLE DIGITS. AND THE COLD
LOOKS TO TAKE UP RESIDENCE FOR A WHILE.  THE UPPER LEVEL POLAR
TROUGH WILL REMAIN IN PLACE OVER SOUTHERN CANADA INTO NEXT WEEK.
SURFACE HIGH PRESSURE OVER 1040MB SLIDING INTO THE UPPER MIDWEST
FOR THE WEEKEND...LEADING TO LOWS BELOW ZERO FOR MUCH OF MN AND
NORTHERN WI. A WEAK WAVE PASSES ACROSS THE CENTRAL PART OF THE
COUNTRY ON SUNDAY...JUST AS THE LARGE POLAR VORTEX SENDS THE NEXT
SEVERAL DISTURBANCES DOWN INTO OUR AREA. THE COMBINATION LOOKS TO
PROVIDE A CHANCE FOR SNOW SUNDAY NIGHT INTO MONDAY. THE ECMWF IS
MOST ROBUST WITH SNOW CHANCES...PERHAPS 1-4 INCHES? OTHER MODELS
NOT QUITE AS BULLISH. THIS WILL HAVE TO BE MONITORED. BEHIND THAT
SYSTEM...THE COLD AIR RETURNS...SENDING LOWS WELL BELOW ZERO AGAIN
FOR TUESDAY AND WEDNESDAY NEXT WEEK.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1100 PM CST TUE DEC 3 2013

LIFR/IFR CONDITIONS EXPECTED THROUGH MUCH OF WED AS A MOISTURE LADEN
ATMOSPHERE HOLDS ACROSS THE REGION. ISENTROPIC UPGLIDE ON THE 275-
290 K SFCS WILL WORK ON THE MOISTURE...MAKING -DZ LIKELY THROUGH WED
MORNING. FG/BR WILL ALSO CONTINUE. THE LOW LEVEL THERMODYNAMICS MOVE
OFF FOR THE AFTERNOON AS A COLD FRONT SWEEPS IN BETWEEN 18-21Z. THE
FRONT COUPLED WITH SOME UPPER LEVEL LIFT SHOULD RESULT IN AREAS OF
-SN/-RA ALONG AND BEHIND THE FRONT. SOME CONCERN VIA THE NAM BUFKIT
SOUNDINGS THAT THERE MIGHT NOT BE ICE IN THE CLOUD...THUS LIQUID
PCPN...AND A POTENTIAL FOR FREEZING PCPN AS COLDER AIR WORKS IN LATE
AFTERNOON/EVENING. GFS DEEPER IN ITS SATURATION AND HAS ICE. GOING
TO SIDE THIS WAY FOR NOW...BUT SOMETHING TO WATCH. SNOW ACCUM LOOKS
MINOR...MOSTLY AT KRST WITH 1/2 INCH OR LESS EXPECTED THERE. WINDS
WILL PICK UP POST THE FRONT...STAYING STRONG AND GUSTY THROUGH THU.

SHOULD SEE SOME IMPROVEMENT IN CIGS THU EVENING...BUT LOOKING MORE
LIKELY THAT THEY WILL STILL STAY MVFR...IF NOT IFR...FOR MUCH OF THU
NIGHT. BETTER CHANCE FOR CLEARING BY EARLY FRI MORNING.

&&

.ARX WATCHES/WARNINGS/ADVISORIES...
WI...DENSE FOG ADVISORY UNTIL NOON CST WEDNESDAY FOR WIZ032>034-
     041>044-053>055-061.

     WINTER WEATHER ADVISORY TO 6 AM CST
     THURSDAY FOR WIZ017-029.

MN...DENSE FOG ADVISORY UNTIL NOON CST WEDNESDAY FOR MNZ079-086>088-
     094>096.

IA...DENSE FOG ADVISORY UNTIL NOON CST WEDNESDAY FOR IAZ008>011-018-
     019-029-030.

&&

$$

SHORT TERM...MW
LONG TERM....MW
AVIATION.....RIECK