Area Forecast Discussion
Issued by NWS La Crosse, WI

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FXUS63 KARX 280453
AFDARX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
1053 PM CST FRI FEB 27 2015

.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 352 PM CST FRI FEB 27 2015

AT 3 PM...A 1039 MB HIGH CENTERED OVER ILLINOIS PRODUCED CLEAR
SKIES ACROSS THE UPPER MISSISSIPPI RIVER VALLEY. DESPITE THE
SUNSHINE...TEMPERATURES REMAIN IN THE 5 TO 15 DEGREE RANGE. THESE
TEMPERATURES ARE 20 TO 25 DEGREES BELOW NORMAL.

FOR TONIGHT...THE 27.12Z MODELS SHOW THAT THE HIGH WILL MOVE EAST
INTO WESTERN PENNSYLVANIA. EVEN THOUGH THE HIGH WILL BE MOVING
AWAY FROM THE REGION...SKIES WILL REMAIN MOSTLY CLEAR. THE WINDS
WILL BECOME SOUTHERLY AND REMAIN IN THE 5 TO 10 MPH RANGE
OVERNIGHT AND SATURDAY MORNING. WITH THE MOSTLY CLEAR
SKIES...TEMPERATURES WILL FALL INTO THE -5 TO -25 DEGREE RANGE.
THE COLDEST TEMPERATURES WILL BE FOUND IN CENTRAL WISCONSIN. THE
COMBINATION OF THESE TEMPERATURES AND WINDS WILL PRODUCE WIND
CHILLS OF -15 TO -30 FROM AFTER MIDNIGHT THROUGH MID MORNING
SATURDAY. THE COLDEST WIND CHILLS WILL BE FOUND IN NORTHEAST IOWA
AND SOUTHEAST MINNESOTA. THIS IS DUE TO A SLIGHTLY HIGHER PRESSURE
GRADIENT IN THESE AREAS. DUE TO THIS...ISSUED A WIND CHILL
ADVISORY FROM MIDNIGHT THROUGH 9 AM SATURDAY.

.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 352 PM CST FRI FEB 27 2015

FOR SATURDAY NIGHT AND SUNDAY...THE 27.12Z MODELS SHIFTED THE
SOUTHERN STREAM SYSTEM A BIT FURTHER SOUTH. IT NOW TRACKS THIS
SYSTEM FROM THE CENTRAL PLAINS INTO THE SOUTHERN GREAT LAKES. DUE
TO THIS...THE BEST 925 AND 850 MB MOISTURE TRANSPORT ALONG WITH
THE 900 TO 700 MB FRONTOGENESIS IS NOW LOCATED TO OUR WELL TO OUR
SOUTH IN A MAJORITY OF THE MODELS. THE ONE EXCEPTION IS THE
OPERATIONAL GFS WHICH STILL PRODUCES SNOW ACROSS MUCH OF THE AREA.
HOWEVER THIS MODEL IS AT ODDS WITH ITS MODEL ENSEMBLE. 10 OF THE
12 GFS MEMBERS RESEMBLE THE OPERATIONAL GEM/ECMWF/NAM SOLUTIONS.
DUE TO THIS LOWERED THE PRECIPITATION CHANCES AND SNOW AMOUNTS
ACROSS NORTHEAST IOWA AND SOUTHWEST WISCONSIN. AT THIS TIME...IT
LOOKS LIKE THESE AREAS WILL ONLY SEE A TRACE TO A HALF INCH OF
SNOW. FURTHER NORTH...A SHORT WAVE IN THE NORTHERN STREAM WILL BE
MOVING ACROSS NORTHERN MINNESOTA AND NORTHERN WISCONSIN.
FROM THE SOUNDINGS...IT LOOKS LIKE THIS SYSTEM IS FAIRLY MOISTURE
STARVED...SO JUST KEPT A 20 PERCENT CHANCE OF SNOW NORTH OF
INTERSTATE 94 TO HANDLE THE POSSIBILITY THAT SOME VERY LIGHT SNOW
MAY FALL.

FROM MONDAY NIGHT INTO TUESDAY NIGHT...THE MODELS CONTINUE TO SHOW
THAT THAT SOUTHERN STREAM SHORT WAVE TROUGH WILL BE MOVING
THROUGH THE REGION. THIS SYSTEM IS A BIT FURTHER SOUTH...SO THE
WINTRY MIX WAS SHIFTED SOUTH INTO THE SOUTHERN PORTIONS OF FAYETTE
AND CLAYTON COUNTIES IN NORTHEAST IOWA AND SOUTHERN GRANT COUNTY
IN SOUTHWEST WISCONSIN. THE MODELS CONTINUE TO GENERATE ANYWHERE
FROM A THIRD TO THREE QUARTERS OF AN INCH OF LIQUID. SOUNDINGS
SHOW THAT ONLY A SMALL PORTION OF THE THERMAL PROFILE BETWEEN 500
AND 600 MB IS LOCATED IN THE DENDRITIC GROWTH ZONE. AS A RESULT...
EXPECT SNOW TO LIQUID RATIOS TO BE IN THE 10-15 TO 1 RANGE. WITH
THIS IN MIND...IT LOOKS LIKE WE WILL SEE ANYWHERE FROM 3 TO 6
INCH RANGE.

IN THE WAKE OF THIS SYSTEM...ANOTHER COLD SHOT WILL MOVE INTO THE
AREA. HIGHS ON WEDNESDAY LOOK TO BE IN THE TEENS AND FROM 5 TO 15
ON THURSDAY.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1049 PM CST FRI FEB 27 2015

VFR CONDITIONS EXPECTED THROUGH SATURDAY. SATURDAY NIGHT...A
STORM WILL TRAVEL THROUGH ILLINOIS AND COULD BRING MVFR CIGS TO
THE TAF SITES FROM ABOUT MID EVENING ON. CONFIDENCE WAS NOT HIGH
ENOUGH TO INCLUDE THIS FORECAST CEILING YET HOWEVER.

&&

.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...WIND CHILL ADVISORY UNTIL 9 AM CST SATURDAY FOR MNZ086-087-094-
     095.

IA...WIND CHILL ADVISORY UNTIL 9 AM CST SATURDAY FOR IAZ008>010-018-
     019-029-030.

&&

$$

SHORT TERM...BOYNE
LONG TERM...BOYNE
AVIATION...BAUMGARDT


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