Area Forecast Discussion
Issued by NWS La Crosse, WI

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000
FXUS63 KARX 260834
AFDARX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
234 AM CST WED NOV 26 2014

.UPDATE...
ISSUED AT 234 AM CST WED NOV 26 2014

WATER VAPOR IMAGERY SHOWING VIGOROUS MID-LEVEL TROUGH/CIRCULATION
CENTER OVER SOUTHWEST MN...MOVING SOUTHEAST. LIGHT SNOW BANDS
MOVING NORTHEAST INTO THE CURRENT WINTER WEATHER ADVISORY ACROSS
PORTIONS OF SOUTHEAST MN/NORTHEAT IA. STILL LOOKING AT MAINLY 3...TO
SOME PERHAPS A COUPLE POCKETS OF 4 INCH TOTAL ACCUMULATIONS ON THE
WESTERN FRINGE OF THE ADVISORY AREA FOR TODAY. I ALSO INCLUDED
DODGE COUNTY IN THE ADVISORY...SEE WATCH/WARNING/ADVISORY SECTION
BELOW FOR DETAILS.

&&

.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 353 PM CST TUE NOV 25 2014

AT 3 PM...A SURFACE LOW WAS LOCATED OVER WESTERN NORTH DAKOTA.
THIS SYSTEM WAS PRODUCING MODERATE TO HEAVY SNOW WITH
VISIBILITIES AS LOW AS A HALF MILE AT HARVEY MUNICIPAL AIRPORT IN
CENTRAL NORTH DAKOTA. AS THIS LOW MOVES SOUTHEAST INTO EASTERN
SOUTH DAKOTA...MODERATE TO STRONG WARM AIR ADVECTION AND WEAK TO
MODERATE 275 TO 285K ISENTROPIC LIFT WILL DEVELOP ACROSS SOUTHEAST
MINNESOTA AND NORTHEAST IOWA. THIS WILL RESULT IN A RAPID
SATURATION OF THE SOUNDINGS BETWEEN 26.06Z AND 26.09Z. THIS WILL
RESULT IN THE DEVELOPMENT OF SNOW. WITH SOUNDINGS SHOWING UP TO
75 MB IN THE DENDRITIC GROWTH ZONE...WENT WITH A 13-15 TO 1 SNOW
TO LIQUID RATIOS. AS FAR AS QPF TRENDED THE FORECAST MORE TOWARD
THE ECMWF. BELIEVE THAT BOTH THE GFS AND GEM HAVE TOO MUCH
PHASING TAKING PLACE BETWEEN THE SHORT WAVE PASSING TO OUR
SOUTHWEST AND SOUTH AND THE APPROACHING ARCTIC COLD
FRONT...THEREFORE...HIGHER QPF. LIKE PREVIOUS RUNS OF THE 25.15Z
SPC SREFS FOR CHARLES CITY IOWA AND ALBERT LEA MINNESOTA CONTINUE
TO SHOW 3 DISTINCT SOLUTIONS. THE FIRST GROUP BRINGS THE SNOW INTO
THE AREA BETWEEN 06Z AND 12Z...AND THEN CONTINUE TO SNOW THROUGH
WEDNESDAY. THIS SET OF 7 MODELS PRODUCE ANYWHERE FROM 1.5 TO 4
INCHES OF SNOW FOR CHARLES CITY AND 2 TO 5 INCHES FOR ALBERT LEA.
THE SECOND GROUP DEVELOPS SNOW BETWEEN 12Z AND 18Z WEDNESDAY WITH
MUCH HIGHER RATES AND ALSO ENDS AROUND 00Z THURSDAY. SNOW TOTALS
ARE VERY SIMILAR TO THE FIRST FAMILY. THE REMAINING 5 MODELS HAVE
VERY LITTLE SNOW WITH THE SHORT WAVE PASSING TO OUR SOUTHWEST AND
THEN BRINGS UP TO AN INCH WITH THE ARCTIC COLD FRONT. TRENDED THE
FORECAST TOWARD THE FIRST SET OF MODELS. AT THIS TIME...IT LOOKS
LIKE 2 TO 4 INCHES OF SNOW WILL FALL ACROSS MOWER IN SOUTHEAST
MINNESOTA... AND MITCHELL...FLOYD...AND CHICKASAW COUNTIES IN
NORTHEAST IOWA FROM 3 AM THROUGH 6 PM WEDNESDAY. ELSEWHERE ACROSS
SOUTHEAST MINNESOTA AND NORTHEAST IOWA EXPECT 1 TO 2 INCHES OF
SNOW. FINALLY IN WESTERN WISCONSIN SNOW TOTALS WILL BE LESS THAN
AN INCH.

.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 353 PM CST TUE NOV 25 2014

ON WEDNESDAY NIGHT...AN ARCTIC COLD FRONT WILL MOVE QUICKLY
SOUTHEAST THROUGH THE FORECAST AREA. THE BEST SYNOPTIC LIFT
ASSOCIATED WITH FRONT WILL CLOSER TO THE SHORT WAVE TROUGH MOVING
ACROSS NORTHEAST MINNESOTA AND NORTHERN WISCONSIN. SOUNDINGS NORTH
OF INTERSTATE 90 SHOW UP TO 100 MB OF OMEGA LOCATED IN THE
DENDRITIC GROWTH ZONE MAINLY DURING THE EVENING. AS A RESULT WENT
WITH SNOW TO LIQUID RATIOS CLOSER TO A 15 TO 1 RATIO. THIS RESULTS
IN SNOW TOTALS UP TO A HALF INCH NORTH OF INTERSTATE 90.

ON THANKSGIVING...EXPECT DRY CONDITIONS AS THE ARCTIC HIGH BUILDS
EAST ACROSS THE AREA. HIGH TEMPERATURES WILL LIKELY OCCUR CLOSE
TO MIDNIGHT...AND THEN TEMPERATURES WILL SLOWLY THROUGHOUT MUCH OF
THE MORNING. TEMPERATURES WILL THEN RISE BACK INTO THE 10 TO 20
DEGREE RANGE FOR THE AFTERNOON. THE CURRENT FORECAST HIGH
TEMPERATURE FOR LA CROSSE IS 16 DEGREES. THE LAST TIME THAT WE HAD
A THANKSGIVING WITH A HIGH IN THE TEENS WAS 1958 WHEN THE HIGH
TEMPERATURE WAS 19 DEGREES. THERE HAVE ONLY BEEN 11 THANKSGIVINGS
SINCE 1872 THAT HAVE HAD HIGH TEMPERATURES IN THE TEENS OR COLDER.
THE COLDEST HIGH TEMPERATURE FOR THANKSGIVING IS 3 IN 1872.

ON THURSDAY NIGHT AND FRIDAY...MODERATE TO STRONG WARM AIR
ADVECTION DEVELOPS ACROSS THE AREA AS A SHORT TROUGH MOVES ACROSS
NORTHERN MINNESOTA. SOUNDINGS SUGGESTS THAT THERE WILL BE 200 TO
300 MB OF OMEGA LOCATED IN THE DENDRITIC GROWTH ZONE. THIS WILL
INCREASE SNOW TO LIQUID RATIOS INTO THE 20-25 TO 1. THIS HAS THE
POTENTIAL OF PRODUCING SNOW TOTALS INTO THE 2 TO 4 INCH RANGE
ACROSS TAYLOR AND CLARK COUNTIES. SOUNDINGS ALSO SHOW SOME DRY AIR
MOVING INTO AREAS BETWEEN INTERSTATE 94 AND 90. THIS MAY RESULT
IN SOME FREEZING DRIZZLE IF THE LIFT HAS NOT LEFT THE AREA.

ON SATURDAY AFTERNOON AND NIGHT...ANOTHER ARCTIC COLD FRONT WILL
PUSH SOUTH THROUGH THE AREA. THIS WILL RESULT IN HIGH TEMPERATURES
OF 15 TO 30 ON SUNDAY.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1115 PM CST TUE NOV 25 2014

THE 26.00Z KDVN SOUNDING SHOWED A CONSIDERABLE AMOUNT OF DRY AIR
IN THE LOW LEVELS THAT WILL CONTINUE TO GET DRAWN INTO THE AREA ON
THE SOUTH WINDS AHEAD OF THE APPROACHING SURFACE LOW. DEW POINT
DEPRESSIONS ARE BETWEEN 5 AND 10 DEGREES AS FAR WEST AT THE
MISSOURI RIVER AS OF 26.05Z. WHILE THERE WAS LITTLE CHANGE IN THE
OVERALL FORCING SIGNALS IN THE 26.00Z NAM AND GFS...THIS DRY AIR
WILL HELP TO DELAY THE ARRIVAL OF ANY SNOW FROM THIS SYSTEM. THE
ONE TREND NOTED IN THE MODELS WAS A SOUTHWESTWARD SHIFT IN THE
SNOW DUE TO THE DRY AIR. HAVE THUS PUSHED BACK THE ARRIVAL TIME OF
THE SNOW AND WILL NOW SHOW FLURRIES COMING INTO KRST DURING THE
MID MORNING HOURS BEFORE GOING DOWN WITH IFR VISIBILITIES AND MVFR
CEILINGS FOR A GOOD SHARE OF THE AFTERNOON. THE FORCING SHOULD
QUICKLY DIMINISH WEDNESDAY EVENING AS THE SHORT WAVE TROUGH MOVES
PAST AND BROUGHT THE VISIBILITY UP TO VFR BUT KEPT THE CEILINGS
DOWN AS THE NAM BUFKIT SOUNDINGS SUGGEST THE LOW LEVELS UNDERNEATH
THE INVERSION SHOULD STAY SATURATED. ALSO DELAYED THE ARRIVAL OF
THE SNOW AT KLSE WITH THE FLURRIES COMING IN DURING THE AFTERNOON
WITH A PERIOD OF MVFR CONDITIONS FOR THE LATE AFTERNOON AND EARLY
EVENING. SHOULD THEN SEE JUST FLURRIES FOR THE LATE EVENING WITH
THE CEILINGS STAYING MVFR.


&&

.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...WINTER WEATHER ADVISORY UNTIL 6 PM CST THIS EVENING FOR MNZ086-
     094.

IA...WINTER WEATHER ADVISORY UNTIL 6 PM CST THIS EVENING FOR IAZ008-
     018-019.

&&

$$

UPDATE...DAS
SHORT TERM...BOYNE
LONG TERM...BOYNE
AVIATION...04



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