Area Forecast Discussion
Issued by NWS La Crosse, WI

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313
FXUS63 KARX 111728
AFDARX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
1128 AM CST THU FEB 11 2016

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 345 AM CST THU FEB 11 2016

AT 3 AM...AT 1028 MB SURFACE HIGH WAS LOCATED ACROSS THE AREA.
THIS HIGH WAS PRODUCING CLEAR SKIES AND LIGHT WINDS. SURFACE
TEMPERATURES RANGED FROM -13F AT BLACK RIVER FALLS TO 3F AT
DECORAH AND OELWEIN.

FOR TONIGHT...THE CONTINUE TO BE SOME DIFFERENCES ON HOW CLOSE THE
BAROCLINIC ZONE WILL GET TO THE AREA. THE 11.00Z GEM AND ECMWF
KEEP THIS WELL SOUTHWEST OF THE AREA...THUS...THEY KEEP THE AREA
DRY. MEANWHILE THE GFS AND NAM HAVE IT NEARBY AND AS A RESULT
PARTS OF SOUTHEAST MINNESOTA AND NORTHEAST WILL PICK UP SOME
LIGHT SNOW. LOOKING AT THE 11.06Z RUNS...THE GFS HAS TRENDED
FURTHER SOUTHWEST WITH THE TRACK OF THIS SNOW BAND. MEANWHILE THE
NAM STILL HAS IT MOVING THE NORTHERN EDGE THROUGH MOWER AND
FILLMORE COUNTIES IN SOUTHEAST MINNESOTA...NORTHEAST IOWA...AND
SOUTHWEST WISCONSIN. LOOKING AT WHERE THIS SNOW BAND IS CURRENTLY
LOCATED...FEEL THAT THE SNOW BAND WILL LIKELY JUST MOVE SOUTHEAST
OF THE AREA. HOWEVER WAS NOT CONFIDENT ENOUGH TO COMPLETELY TO
REMOVE THE 20 TO 40 PERCENT CHANCES OF SNOW FROM THESE AREAS. IF
SNOW DOES INDEED OCCURS...SNOW AMOUNTS WOULD BE LESS THAN A HALF
INCH.

.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 345 AM CST THU FEB 11 2016

ON FRIDAY AFTERNOON AND NIGHT...A VERY COLD AIR MASS SETTLES
SOUTH ACROSS EASTERN ONTARIO AND QUEBEC. 850 MB TEMPERATURES FALL
INTO THE -36 TO -40C RANGE. THIS IS 4 TO 4.5 STANDARD DEVIATIONS
BELOW NORMAL. ACCORDING TO THE CIPS ANALOGS...THIS WOULD BE THE
COLDEST AIR MASS IN THIS REGION SINCE JANUARY 13 2004. LIKE THAT
AIR MASS WE WILL BE ON THE WESTERN PERIPHERY OF THIS COLD AIR
MASS. THE TEMPERATURES FOR THAT ANALOG WAS ACTUALLY MUCH WARMER
/-8C THEN AND TO -20 THIS TIME/ FOR US THAN DURING THAT ARCTIC
OUTBREAK. UNDER MOSTLY CLEAR SKIES AND LIGHT NORTHWEST
WINDS...TEMPERATURES WILL FALL -7 TO -19F RANGE. WITH WINDS CHILLS
OF -20 TO -35 ACROSS THE AREA...A WIND CHILL ADVISORY WILL LIKELY
BE NEEDED.

ON SATURDAY...THE STRONG ARCTIC HIGH PRESSURE AREA WILL DRIFT EAST
OF THE FORECAST AREA DURING THE MORNING. AS THIS OCCURS...THE 925
AND 850 MB TEMPERATURES WILL WARM 4 TO 6C. THIS MAKES THE FORECAST
FOR THE MAXIMUM TEMPERATURE RATHER TRICKY. THE MODEL CONSENSUS HAS
HIGH TEMPERATURES RANGING FROM 4 TO 12F. THIS IS ACTUALLY CLOSE TO
THE ECMWF SEEMS MUCH REASONABLE AND THIS MODEL HAS BEEN OUT
PERFORMING THE GFS ON SURFACE TEMPERATURES FOR THAT TIME PERIOD.
WHILE THESE TEMPERATURES WILL BE CLOSE TO THE COLDEST MAXIMUM
TEMPERATURES FOR FEBRUARY 13TH...NOT ANTICIPATING TOO MANY
RECORDS.

FROM LATE SATURDAY NIGHT INTO SUNDAY NIGHT...STRONG WARM AIR
ADVECTION DEVELOPS ACROSS THE FORECAST AREA IN THE WAKE OF
DEPARTING ARCTIC HIGH. IN ADDITION...THERE WILL BE A STRONG
EASTWARD PROPAGATING 900 TO 800 MB FRONTOGENETIC BAND. THIS WILL
RESULT IN A BAND OF SNOW MOVING ACROSS THE AREA. DESPITE THE AIR
MASS BEING COLD...SOUNDINGS ARE NOT SHOWING A DEEP DENDRITIC ZONE.
THIS WILL HELP KEEP THE SNOW TO LIQUID RATIOS IN THE 15-20 TO 1
RANGE. COBB DATA CONTINUE TO SHOW SNOW TOTALS IN THE 3 TO 6
RANGE. IF THESE HOLD...THERE MAY BE A NEED OF A WINTER WEATHER
ADVISORY.

ADDITIONAL SHORT WAVES MOVE THROUGH THE AREA FROM MONDAY THROUGH
WEDNESDAY. THE MODELS CONTINUE TO STRUGGLE GREATLY WITH THE TIMING
OF THESE SYSTEMS THROUGH THE AREA. AT THIS TIME...THE SYSTEMS
EARLY IN THE WEEK LOOK TO BE SNOW PRODUCERS...BUT AS WE HEAD INTO
THE MIDDLE OF THE WEEK A WINTRY MIX OF PRECIPITATION MAY OCCUR.
TEMPERATURES THROUGH THIS TIME PERIOD WILL BE CLOSE TO ABOVE
NORMAL. DUE TO THE INCONSISTENCY IN THE MODELS...JUST WENT WITH
THE MODEL CONSENSUS FOR TEMPERATURES AND PRECIPITATION CHANCES.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1128 AM CST THU FEB 11 2016

VFR CONDITIONS PREVAIL AT MOMENT BUT AS HIGH PRESSURE DRIFTS OFF AND
APPROACHING WAVE MOVES CLOSER...CEILINGS COULD LOWER TO MVFR AT
TIMES LATER TODAY AND TONIGHT. UPSTREAM WAVE HAS SOME FRONTOGENETIC
LIFT IN MID LEVELS BUT SOME FORCING WILL GO INTO SATURATION. TRENDS
IN MODELS HAVE BEEN SHIFTING ASSOCIATED PRECIPITATION A BIT MORE
SOUTHWEST...BARELY CLIPPING OUR AREA. WILL WATCH THIS TREND AS LIGHT
SNOW APPROACHES...BUT EXPECTING MINIMAL IMPACT. BEHIND WAVE...
IMPROVING CONDITIONS SHOULD RETURN TO VFR.

&&

.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&

$$

SHORT TERM...BOYNE
LONG TERM...BOYNE
AVIATION...SHEA



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