Area Forecast Discussion
Issued by NWS La Crosse, WI

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FXUS63 KARX 282250
AFDARX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
450 PM CST FRI NOV 28 2014

.UPDATE...
ISSUED AT 450 PM CST FRI NOV 28 2014

SCATTERED FREEZING RAIN SHOWERS CONTINUE ALONG AND NORTH OF
INTERSTATE 90 WITH SOME LOCAL LAW ENFORCEMENT AGENCIES STARTING TO
REPORT SOME SLIC ROADS AND ACCIDENTS. LOOKING AT THE LATEST
HRRR...THIS SHOULD CONTINUE INTO THE EARLY EVENING BEFORE PUSHING
OFF TO THE EAST AND OPTED TO ISSUE A FREEZING RAIN ADVISORY WITH
SOME ICING STARTING TO OCCUR AND TO RAISE THE AWARENESS.

&&

.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 350 PM CST FRI NOV 28 2014

AT 3 PM...A BAND OF MODERATE TO STRONG 700 TO 500 MB FRONTOGENESIS
WAS STARTING TO MOVE EAST INTO WEST CENTRAL WISCONSIN. THIS BAND
HAS PRODUCED AREAS OF FREEZING RAIN AND OCCASIONALLY SOME ICE
PELLETS ACROSS SOUTHEAST MINNESOTA. PERIODIC CHECKS WITH LAW
ENFORCEMENT AND SPOTTERS HAVE NOT INDICATED TOO MUCH OF AN IMPACT
FROM IT. IT JUST STARTED HERE AT THE OFFICE AND IT IS FREEZING ON
THE VEHICLES AND SLICK SPOTS ON UNTREATED SIDEWALKS. HAVE TO ISSUE
A SPECIAL WEATHER STATEMENT FOR AREAS ALONG AND NORTH OF
INTERSTATE 90 TO COVER THE POTENTIAL FOR LIGHT ICING ON UNTREATED
SURFACES.

FOR THIS EVENING...THE 28.18Z RAP AND NAM SHOW THAT THIS BAND WILL
CONTINUE TO MOVE EAST ACROSS WEST CENTRAL...CENTRAL...AND NORTH
CENTRAL WISCONSIN. AS IT MOVES INTO NORTH CENTRAL WISCONSIN...
SOUNDINGS SUGGEST THAT THERE MAY BE A BRIEF PERIOD OF SNOW MIXING
IN WITH THIS WINTRY MIX. SOME OF THE MESO MODELS SUGGEST UP TO A
TENTH OF AN INCH OF QPF. THIS SEEMS TO BE A BIT ON THE HIGH SIDE
CONSIDERING THE DRY AIR BETWEEN 700 TO 850 MB...SO HAVE LIQUID
AMOUNTS OF 0.01 TO 0.03 INCHES.

FOR OVERNIGHT...EXPECT THE WINTRY PRECIPITATION TO BE IN CLARK AND
TAYLOR COUNTIES...AND THEN MOVE OUT BY 3 AM. THERE MAY BE SOME
VERY LIGHT ICING. STRONG WARM AIR ADVECTION WILL CAUSE RISING
TEMPERATURES THROUGH THE NIGHT. TEMPERATURES WILL RISE FROM THE
LOWER TO MID 20S INTO THE MID AND UPPER 20S BY MORNING. AS THIS
WARM AIR MOVES OVER THE SNOW PACK...THERE MAY BE SOME AREAS OF
FOG.

ON SATURDAY...THE TEMPERATURE FORECAST IS PROBLEMATIC DUE TO THE
SNOW COVER. THE NAM SNOW COVER IS INITIALIZED TOO HIGH. IT HAS
SNOW DEPTHS OF 4 TO 8 INCHES. WE ARE ACTUALLY MORE IN THE TRACE TO
4 INCHES...SO SOME OF THE WARMING IN THE MODELS IS GOING TO SNOW
MELT INSTEAD OF WARMING THE AIR MASS NEAR THE GROUND. THE WARMEST
925 AND 850 MB TEMPERATURES ARE LOCATED ALONG AND SOUTH OF
INTERSTATE 90. 925 MB TEMPERATURES WILL CLIMB TO 0 TO 8C INTO
THESE AREAS...SO A BIT CONCERNED THAT THE TEMPERATURES COULD WARM
A BIT WARMER THAN THE LOW TO MID 40S THAT ARE CURRENTLY FORECAST.

.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 350 PM CST FRI NOV 28 2014

ON SATURDAY NIGHT AND SUNDAY MORNING...THE FIRST OF 2 ARCTIC COLD
FRONT WILL MOVE SOUTHEAST THROUGH THE AREA. 850 MB TEMPERATURES
FALL FROM 6 TO 10C INTO -7 TO -15C. THE STRONG COLD AIR ADVECTION
WILL CAUSE TEMPERATURES TO SLOWLY FALL THROUGH MUCH OF THE DAY.
WAS INITIALLY CONCERNED ABOUT STRONG WINDS ADVECTING TO THE
SURFACE DUE TO STRONG SUBSIDENCE IN THE WAKE OF THIS FRONT.
HOWEVER SOUNDINGS CONTINUE TO SHOW THAT THE WINDS WILL STAY
MAINLY IN THE 15 TO 25 MPH. THIS WILL PRODUCE WIND CHILLS IN THE
10 BELOW TO 10 ABOVE RANGE.

ON SUNDAY NIGHT...ANOTHER COLD FRONT WILL MOVE THROUGH THE AREA.
THIS WILL LOWER 850 MB TEMPERATURES DOWN INTO THE -15C TO -19C FOR
MONDAY MORNING BEFORE WARM AIR ADVECTION STARTS TO DEVELOP ACROSS
THE AREA DURING THE AFTERNOON AND MONDAY NIGHT. HIGH TEMPERATURES
ON MONDAY WILL RANGE FROM 5 TO 15 DEGREES. LIGHTER WINDS WILL KEEP
WIND CHILLS IN THE 10 BELOW TO 10 ABOVE RANGE.

FROM THURSDAY INTO THURSDAY NIGHT...THE MODELS CONTINUE TO
STRUGGLE WITH WHETHER A LOW PRESSURE SYSTEM WILL BRING
PRECIPITATION TO THE AREA. THE GFS AND ECMWF ARE NOW SIMILAR WITH
THE TRACK THROUGH THE MID MISSISSIPPI RIVER VALLEY AND WESTERN
GREAT LAKES. HOWEVER THEY ARE 12 HOUR APART. PRECIPITATION TYPE
WILL BE SNOW.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1110 AM CST FRI NOV 28 2014

MODELS SEEM TO BE OVERDOING THE AMOUNT OF LOW LEVEL SATURATION
CURRENTLY ACROSS THE AREA...ESPECIALLY THE NAM. THERE IS AN MVFR
DECK OF CLOUDS TO THE NORTH-WEST...ASSOCIATED WITH AN UPPER LEVEL
SHORTWAVE...FRONTOGENETIC FORCING...AND JUST NORTH OF A WARM FRONT.
FARTHER SOUTH...SOME THIN MID CLOUDS WERE ALL THAT WAS EVIDENT. SOME
SUGGESTION THAT THE LOW CIGS WILL SINK SOUTH ACROSS KRST/KLSE THIS
EVENING...WITH PERHAPS SOME AID FROM POOLING MOISTURE ASSOCIATED
WITH THE MELTING SNOW PACK. THIS COULD ALSO RESULT IN SOME
BR...MOSTLY IN THE MVFR RANGE. HAVE PUSHED BACK THE ENCROACHMENT OF
THE LOW CLOUDS BASED ON CURRENT TRENDS...AND WILL ADJUST AS/IF
NEEDED. ASSUMING LOW CLOUDS DO MOVE IN...PROBABLY STICK AROUND
THROUGH THE BETTER PART OF SATURDAY.

SOMETHING ELSE TO WATCH - IF THE LOW CLOUDS ARE REALIZED LATER THIS
AFTERNOON - THERE COULD BE A THREAT FOR SOME -FZDZ. CURRENT FORECAST
BUFKIT SOUNDINGS ARE PROBABLY TOO SHALLOW IN SATURATION DEPTH...BUT
IF ITS DEEPER...DRIZZLE PROCESS COULD GET GOING THANKS TO SOME WEAK
LIFT THROUGH THE COLUMN. SOMETHING TO MONITOR.


&&

.ARX WATCHES/WARNINGS/ADVISORIES...
WI...FREEZING RAIN ADVISORY UNTIL 9 PM CST THIS EVENING FOR WIZ029-
     032>034-041>044.

MN...FREEZING RAIN ADVISORY UNTIL 9 PM CST THIS EVENING FOR MNZ079-
     086>088.

IA...NONE.
&&

$$

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



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