Area Forecast Discussion
Issued by NWS La Crosse, WI

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FXUS63 KARX 261730
AFDARX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
1130 AM CST WED NOV 26 2014

.UPDATE...
ISSUED AT 1019 AM CST WED NOV 26 2014

THE MAIN FOCUS THIS MORNING IS ON THE SNOW THAT HAS DEVELOPED
ACROSS TWO AREAS LOCALLY...ONE WITH CLOSED MID LEVEL LOW DIVING
INTO WESTERN ILLINOIS AND ANOTHER WITH A SHORT WAVE/SURFACE COLD
FRONT DIVING SOUTH ACROSS CENTRAL MINNESOTA/NORTHWEST WISCONSIN.
MUCH OF THE DEEP LIFT HAS SHIFTED SOUTH WITH THE FIRST WAVE WITH
THE DRY LOW LEVEL AIR TAKING OVER IN ITS WAKE ACROSS NORTHEAST
IOWA. THAT JUST LEAVES THE TROUGH TO THE NORTHWEST FOR ANY SNOW
CHANCES GOING INTO TONIGHT. THE DEEPEST LIFT WILL OCCUR NOW
THROUGH THE EARLY AFTERNOON DUE TO STRONG FRONTOGENESIS AROUND
700MB THAT IS CURRENTLY IN THE AREA THAT THE HEAVIEST SNOW IS
FALLING JUST SOUTH OF THE TWIN CITIES. THIS BAND WILL MEET UP WITH
THE COLD FRONT BAND AND SHIFT SOUTH INTO THE AFTERNOON. THE
FRONTOGENESIS WEAKENS INTO THE AFTERNOON...SO EXPECT THAT THE
GENERAL TREND WILL BE FOR THE BAND OF SNOW TO WEAKENS AS IT TRACKS
TO THE SOUTHEAST INTO THIS EVENING. WILL CONTINUE TO KEEP THE
ADVISORY GOING FOR NOW DUE TO THE POTENTIAL TRAVEL IMPACTS...BUT
HAVE DOUBTS ABOUT REACHING ANY SIGNIFICANT TOTALS...PARTICULARLY IN
THE NORTHEAST IOWA COUNTIES IN THE ADVISORY.

&&

.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 338 AM CST WED NOV 26 2014

CURRENT WATER VAPOR IMAGERY SHOWS A VIGOROUS MID-LEVEL
TROUGH/CIRCULATION CENTERED OVER SOUTHWEST MN...MOVING SOUTHEAST.
ISENTROPIC PUSH/850-500MB FRONTOGENESIS OUT AHEAD OF THE WAVE WAS
PRODUCING A COUPLE BANDS OF LIGHT-MODERATE SNOW ACROSS SOUTH-
CENTRAL INTO SOUTHEAST MN AND CENTRAL IA...MOVING NORTHEAST
TOWARD/INTO THE CURRENT WINTER WEATHER ADVISORY. A WINTER WEATHER
ADVISORY IS IN EFFECT THROUGH TODAY/6PM FOR DODGE AND MOWER COUNTIES
IN SOUTHEAST MN AND MITCHELL/FLOYD/CHICKASAW COUNTIES IN NORTHEAST
IA. THERE WILL LIKELY BE A FAIRLY TIGHT EAST TO WEST GRADIENT IN
SNOWFALL THROUGH TODAY DUE TO FRONTOGENESIS DYING OUT AS IT MOVES
NORTHEAST AND POTENTIAL COLUMN SATURATION ISSUES DUE TO DRIER SUB-
CLOUD LAYER THE FARTHER EAST YOU GO. IN THE ADVISORY...THINKING
ANYWHERE FROM 2-4 INCHES IS POSSIBLE...AGAIN WITH HIGHER-END AMOUNTS
IN THE WESTERN FRINGES OF THE ADVISORY. FARTHER EAST...MAINLY UP TO
THE MISSISSIPPI RIVER...ANYWHERE FROM A DUSTING TO AROUND AN INCH
COULD OCCUR. LOOK FOR MAIN FORCING FROM THIS WAVE TO MOVE SOUTHEAST
THIS AFTERNOON...SO EXPECTING A DIMINISHING TREND IN THE SNOW.

MEANWHILE...WILL BE WATCHING AN ARCTIC FRONT DROP SOUTHEAST THROUGH
MN INTO WESTERN WI THIS AFTERNOON...AND THIS IS EXPECTED TO GENERATE
SOME SNOW SHOWER ACTIVITY AS IT PUSHES SOUTHEAST INTO/THROUGH THE
AREA LATER THIS AFTERNOON INTO THIS EVENING. COULD SEE 1/2-1 INCH OUT
OF THIS SNOW SHOWER ACTIVITY BEFORE IT WRAPS UP/EXITS THE AREA SOON
AFTER MIDNIGHT.

OTHERWISE...PLAN ON HIGHS MAINLY IN THE 20S TODAY. LOOK FOR LOWS
TONIGHT RANGING FROM THE SINGLE DIGITS TO THE TEENS WITH CLEARING
SKIES AS ARCTIC AIR SPILLS INTO THE REGION. COULD EVEN SEE A FEW
READING NEAR ZERO OR A COUPLE DEGREES BELOW ZERO ACROSS MN.

.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 338 AM CST WED NOV 26 2014

FOR THANKSGIVING DAY...LOOK FOR SUNNY BUT COLD CONDITIONS AS
MODIFIED ARCTIC AIRMASS SLIDES ACROSS THE AREA. HIGHS ARE EXPECTED
TO ONLY TOP OFF IN THE TEENS.

A WARM FRONT WILL BE APPROACHING THE REGION THURSDAY NIGHT AND
PUSHING THROUGH DURING THE DAY FRIDAY. SIGNAL FOR LIGHT SNOWFALL
THURSDAY NIGHT WAS SUCH THAT WENT WITH CATEGORICAL POPS AFTER
MIDNIGHT FOR AREAS ALONG/NORTHEAST OF I-94. ACROSS THAT AREA...1-2
INCHES OF SNOWFALL LOOKS LIKELY.

DURING THE DAY FRIDAY AS THE WARM FRONT IS PUSHING THROUGH...MODEL
SOUNDINGS ARE INDICATING THERE MAY BE A LOSS OF ICE IN THE CLOUD FOR
SNOW GENERATION...TURNING INTO A FREEZING DRIZZLE THREAT. HAVE ADDED
A SLIGHT CHANCE OF FREEZING DRIZZLE IN THE GRIDS BASED ON THIS
SIGNAL. OTHERWISE...LOOK FOR A CLOUDY DAY WITH HIGHS TOPPING OFF IN
THE 20S TO THE LOWER 30S. LIGHT SNOW/FREEZING DRIZZLE CHANCES LINGER
NORTH OF I-94 FRIDAY NIGHT AS THE WARM FRONT HANGS UP ACROSS THAT
AREA WITH THE NAM MODEL INDICATING A WEAK MID-LEVEL TROUGH RIPPLING
THROUGH AS WELL.

SATURDAY LOOKS TO BE RELATIVELY MILD IN THE WARM SECTOR OF LOW
PRESSURE SYSTEM MOVING ACROSS THE DAKOTAS/NORTHERN MN. LOOK FOR
HIGHS IN THE 30S TO THE LOWER 40S WHICH IS SOME 5 DEGREES ABOVE
NORMAL FOR THAT DATE.

ANOTHER ARCTIC FRONT SLIPS SOUTHEAST ACROSS THE AREA SATURDAY
NIGHT/SUNDAY. IT APPEARS THIS FRONT WILL COME TROUGH DRY THIS
TIME...BUT TEMPERATURES WILL BE HEADING DOWNWARD WITH HIGHS SUNDAY
IN THE TEENS AND 20S.

ARCTIC AIRMASS LINGERS OVER THE AREA MONDAY. DESPITE SUNSHINE...PLAN
ON HIGHS IN THE TEENS AND 20S.

AS THE HIGH/MODIFIED ARCTIC AIRMASS PUSHES EAST ON TUESDAY...WARM
AIR ADVECTION TAKES OVER AS LOW PRESSURE MOVES ACROSS THE DAKOTAS
TOWARD THE REGION. THIS COULD PRODUCE LIGHT RAIN OR SNOW AS HIGHS
CLIMB INTO THE 30S.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1130 AM CST WED NOV 26 2014

SNOW HAS BEEN FALLING AT RST FOR THE PAST FEW HOURS AND WILL
CONTINUE AT THIS INTENSITY THROUGH THE EARLY HALF OF THE AFTERNOON
WITH VISIBILITY STAYING DOWN BETWEEN 3/4-2SM. THIS SNOW IS
EXPECTED TO MAKE IT INTO LSE AROUND 21Z OR SO...BUT LIKELY WILL
NOT BE AS INTENSE AT 2SM OR HIGHER. CONDITIONS WILL IMPROVE LATER
THIS AFTERNOON AND EVENING AFTER THE COLD FRONT MOVES IN AND
BRINGS DRIER AIR DOWN FROM THE NORTH. SOME MVFR CEILINGS WILL
LIKELY HOLD ON THROUGH THE NIGHT BEFORE SCATTERING OUT TOMORROW
MORNING AS A RIDGE OF HIGH PRESSURE MOVES IN FROM THE WEST.

&&

.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...HALBACH
SHORT TERM...DAS
LONG TERM...DAS
AVIATION...HALBACH



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