Area Forecast Discussion
Issued by NWS La Crosse, WI

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000
FXUS63 KARX 121126
AFDARX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
526 AM CST FRI FEB 12 2016

.SHORT TERM...(TODAY THROUGH SUNDAY NIGHT)
ISSUED AT 240 AM CST FRI FEB 12 2016

MESSAGE FROM CANADA TO THE UPPER MISS VALLEY: "LOOK OUT BELOW"! HOPE
YOU`RE READY FOR SOME MORE COLD WEATHER...`CUZ HERE IT COMES. EARLY
MORNING ANALYSIS PLACES AN ARCTIC COLD FRONT DROPPING INTO FAR
NORTHERN MINNESOTA...ON ITS WAY TO CLEARING THE AREA BY MIDDAY...
USHERING IN QUITE THE SHOT OF LOW LEVEL ARCTIC AIR. IN ADVANCE OF
SAID INCOMING AIR...WEAKISH WARM ADVECTION ASCENT CONTINUES TO DRIVE
AN AXIS OF MAINLY LIGHT SNOW OVER PARTS OF THE AREA...THOUGH MAINLY
OF LITTLE CONSEQUENCE PER RADAR TRENDS...WITH PERHAPS UP TO A FRESH
HALF INCH IN A FEW SPOTS THROUGH SUNRISE. BY FAR THE MAIN STORY
THROUGH TODAY AND SATURDAY REMAINS THE COLD...WITH GUSTY WINDS IN A
WELL MIXED LOW LEVEL ENVIRONMENT ALSO A CONCERN TODAY WITH REGARD TO
POTENTIAL FOR BLOWING SNOW. PER UPSTREAM OBS YESTERDAY AND EXPECTED
MIXING UP TO AROUND 875MB LATER TODAY...WE SHOULD BE ABLE TO MUSTER
25-30 KNOTS THROUGH THE MIXED LAYER BY THE AFTERNOON...LIKELY ENOUGH
TO BLOW AROUND WHAT HAS TURNED INTO A VERY GRANULATED (SUGAR-LIKE)
SNOW BASE ON THE GROUND. GIVEN THAT SNOW CONDITION AND EXPECTED
GUSTS...NOT SURE WE WILL BE ABLE TO LOFT MUCH OF THE SNOW FOR A
WIDESPREAD VISIBILITY REDUCTION IN BLOWING SNOW...BUT LIKELY LOOKING
AT SOME DECENT DRIFTING SNOW IN SPOTS.

IN ADDITION...WIND CHILL VALUES WILL BE SLIDING BACK THROUGH THE -10
TO -20F RANGE INTO THE AFTERNOON...FURTHER TAKING A DIVE INTO THE
EVENING WITH ACTUAL SURFACE TEMPS RAPIDLY SLIDING BACK BELOW 0
DEGREES. LIKELY LOOKING AT A PERIOD OF WIND CHILL ADVISORY LEVEL
CONDITIONS FOR MUCH OF THE AREA INTO THE EVENING AND FIRST PART OF
TONIGHT...BEFORE APPROACHING STRONG LOW LEVEL RIDGING (1040+ MB
SURFACE PRESSURES) QUICKLY SHUT DOWN THE WIND AFTER MIDNIGHT. THAT
SETUP WITH DECOUPLING FLOW AND CLEAR SKIES SHOULD EASILY ALLOW MANY
SPOTS TO END UP IN THE DOUBLE DIGITS BELOW ZERO...WITH SOME SPOTS
ACROSS THE WEST (CLOSER TO THE ACTUAL SURFACE RIDGE) AND BOG AREAS
NO DOUBT DIPPING BELOW -20F FOR A TIME. NOT LOOKING LIKE A WHOLE LOT
OF RECOVERY INTO SATURDAY WITH THE RIDGE AXIS OVERHEAD AND LIMITED
MIXING...WITH TEMPS JUST NUDGING INTO THE SINGLE DIGITS ABOVE
ZERO...HELPED ALONG TO A SMALL DEGREE BY THAT INCREASING FEBRUARY
SUN ANGLE.

CLOUDS LOOK TO THICKEN QUICKLY INTO SATURDAY NIGHT AS WARM ADVECTION
ASCENT ALOFT CRANKS UP...LIKELY PRECLUDING ANOTHER REALLY CHILLY
NIGHT...SAVE FOR PERHAPS THE NORTHEAST CWA WHERE A PERIOD CLEAR
SKIES AND LIGHT WINDS THROUGH MIDNIGHT SHOULD ALLOW TEMPS TO TUMBLE.
STILL LOOKING LIKE A PERIOD OF SNOW ADVANCING THROUGH THE REGION
LATER SATURDAY NIGHT INTO SUNDAY...COURTESY OF STRONGER ASCENT AHEAD
OF AN INCOMING UPPER WAVE. STILL SOME QUESTION ABOUT THE PLACEMENT
AND DURATION OF THAT ASCENT...WHICH IN TURN WILL DICTATE SNOW
ACCUMULATION POTENTIAL. PER EARLIER THINKING...THERE IS SOME
POTENTIAL FOR HEADLINE-WORTHY ACCUMULATION...ESPECIALLY SOUTHWEST
HALF OF THE AREA...BUT STILL SOME TIME TO WORK OUT THE DETAILS OF
THIS ONE.

.LONG TERM...(MONDAY THROUGH THURSDAY)
ISSUED AT 240 AM CST FRI FEB 12 2016

THE GOOD NEWS? WARMER WEATHER DOES APPEAR TO BE ON THE WAY...
PARTICULARLY LATER IN THE WORK WEEK. THE BAD NEWS? IT MAY COME AT
THE EXPENSE OF A FEW PERIODS OF SLOPPY WINTER WEATHER AS THOSE FIRST
FEW PUSHES OF WARM AIR TOWARD THE AREA ESSENTIALLY GO INTO
SATURATION AND PERHAPS PRECIP PRODUCTION AT TIMES. TO BE PERFECTLY
HONEST...CONFIDENCE ISN`T EXACTLY THE HIGHEST REGARDING PRECIP
PLACEMENT AND TIMING INTO MIDWEEK...BUT THERE DOES APPEAR TO BE A
DECENT SIGNAL FOR INCREASING SNOW CHANCES TOWARD LATER MONDAY NIGHT
INTO TUESDAY...BUT TIMING AND PLACEMENT OF THE DRIVING SHORTWAVE
DOES SHOW SOME SMALL RUN TO RUN CHANGES EACH GUIDANCE CYCLE. ANOTHER
CHANCE APPEARS PLAUSIBLE TOWARD WEDNESDAY...THOUGH AGAIN EXACT
TIMING IS LIKELY TO CHANGE. SUFFICE IT TO SAY THAT AT SOME
POINT...CHANCES ARE PRETTY GOOD THAT WE WILL SEE A BAND OF SOME
ACCUMULATING SNOWFALL ACROSS THE AREA AS MUCH WARMER AIR MAKES ITS
APPROACH...BUT EXPECT CHANGES OVER THE COMING DAYS. OF BIGGER NOTE
IS AN INCREASING SIGNAL FOR WHAT MAY END UP BEING SOME NICE WARMTH
TOWARD LATE WEEK AS A STRONGER TROUGH WORKS THROUGH THE WESTERN
CONUS...SENDING BUILDING THERMAL RIDGING IN OUR DIRECTION. TOUGH TO
GET TOO EXCITED THIS TIME OF YEAR AS THESE "WARM-UPS" HAVE A
TENDENCY TO GET MUTED WITH TIME...BUT A PERIOD WORTH WATCHING FOR
THOSE LOOKING FOR SOME WARMER WEATHER.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 526 AM CST FRI FEB 12 2016

TROUGH AND LIGHT SNOWFALL MOVING SOUTH OF THE TAF SITES EARLY
THIS MORNING...WITH ANOTHER ARCTIC AIRMASS INVADING THE REGION
TODAY THROUGH TONIGHT. BRISK NORTHWEST WINDS OF 15KT TO 30KT WILL
BE SEEN TODAY AS THIS AIRMASS MOVES IN...SUBSIDING THIS EVENING AS
HIGH PRESSURE BUILDS OVERHEAD. OTHERWISE...PLAN ON VFR CONDITIONS
TODAY THROUGH TONIGHT.

&&

.ARX WATCHES/WARNINGS/ADVISORIES...
WI...WIND CHILL ADVISORY FROM 6 PM THIS EVENING TO 9 AM CST SATURDAY
     FOR WIZ017-029-032>034-041>044-053>055-061.

MN...WIND CHILL ADVISORY FROM 6 PM THIS EVENING TO 9 AM CST SATURDAY
     FOR MNZ079-086>088-094>096.

IA...WIND CHILL ADVISORY FROM 6 PM THIS EVENING TO 9 AM CST SATURDAY
     FOR IAZ008>011-018-019-029-030.

&&

$$

SHORT TERM...LAWRENCE
LONG TERM...LAWRENCE
AVIATION...DAS


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