Area Forecast Discussion
Issued by NWS La Crosse, WI

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FXUS63 KARX 232117
AFDARX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
317 PM CST MON FEB 23 2015

.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 317 PM CST MON FEB 23 2015

THE MAIN FOCUS THROUGH TOMORROW IS ON THE WINDS TONIGHT FOLLOWED
BY SNOW CHANCES LATE TONIGHT INTO TOMORROW MORNING.

CURRENTLY...SOUTHWEST WINDS ARE INCREASING AS THE PRESSURE
GRADIENT TIGHTENS UP ACROSS THE UPPER MISSISSIPPI RIVER VALLEY.
THIS IS AHEAD OF A LOW PRESSURE SYSTEM CURRENTLY ENTERING THE
SOUTHERN PART OF HUDSON BAY. A WARM FRONT EXTENDS SOUTH OUT OF
THIS LOW AND WILL COME THROUGH THE REGION OVERNIGHT INTO TOMORROW
MORNING. WINDS WILL INCREASE THROUGH TONIGHT AS THE CORE OF THE
STRONGEST WINDS PROPAGATES INTO THE REGION. LOOKING
UPSTREAM...MANY OF THE GUSTS ARE IN THE 25 TO 35KT RANGE ACROSS
NORTHERN MINNESOTA/EASTERN DAKOTAS AND THAT SEEMS REASONABLE FOR
WHAT WE SHOULD SEE TONIGHT AS WELL. MUCH OF THE CURRENT SNOW IS
FAIRLY WELL PACKED DOWN AND WE HAVE NOT HAD MUCH IN THE WAY OF
FRESH SNOW...SO THINKING THAT ANY ISSUES WITH BLOWING SNOW WILL BE
RELATIVELY MINOR. PERHAPS JUST SOME DRIFTING OF SNOW ACROSS ANY
OPEN AREAS.

AS THE COLD FRONT MOVES IN OVERNIGHT INTO TOMORROW MORNING...A
BAND OF LIGHT SNOW IS FORECAST COME DOWN ALONG WITH IT. DEEP
FORCING IS LACKING THOUGH THE FRONT MAY PROVIDE ENOUGH LOW LEVEL
LIFT TO GET A BRIEF BAND OF LIGHT SNOW TO FALL. ANY ACCUMULATIONS
LOOK MINOR AT A HALF INCH OR LESS GIVEN THE QUICK PROGRESSION
SOUTHEASTWARD OF THE BAND. SUBSIDENCE BEHIND THE FRONT SHOULD LEAD
TO SOME CLEARING SKIES WHILE THE COLDER AIR MASS TAKE SOME TIME TO
GET BACK IN.

.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 317 PM CST MON FEB 23 2015

THE NEXT MAIN SURGE IN COLDER AIR LOOKS LIKE IT WILL COME IN
THURSDAY MORNING AS ANOTHER TROUGH MOVES THROUGH THE REGION. A
SURFACE LOW ASSOCIATED WITH THIS TROUGH WILL TRACK THROUGH THE
SOUTHERN PLAINS AND BRING A BAND OF LIGHT SNOW ACROSS IOWA ON
WEDNESDAY. THE 23.12Z NAM/GFS CONTINUE TO TREND FURTHER SOUTHWEST
WITH THIS LOW WHILE THE 23.12Z ECMWF/GEM KEEP A FURTHER NORTHEAST
TRACK WHICH BRINGS SNOW INTO NORTHEAST IOWA. ONLY MINOR
ACCUMULATIONS ARE EXPECTED IN NORTHEAST IOWA...BUT IF THE TRACK
GOES FURTHER NORTHEAST WE MAY NEED TO BUMP THEM UP SOME.

TEMPERATURE-WISE...A WIND CHILL ADVISORY MAY BE NEEDED FOR
THURSDAY AND FRIDAY MORNINGS AS THE NEXT COLD AIR MASS SETTLES IN
WITH LOWS DROPPING BACK BELOW ZERO.

THE MAIN FOCUS REMAINS ON THE POTENTIAL FOR A WIDESPREAD
ACCUMULATING SNOW STORM THIS WEEKEND. THE 23.12Z GFS/ECMWF STILL
SHOW A POSITIVE TILT MID LEVEL TROUGH MOVING THROUGH WITH A BROAD
AREA OF SNOW MOVING IN SATURDAY NIGHT INTO SUNDAY. CONFIDENCE
REMAINS RATHER LOW WITH THIS SYSTEM AS THE GFS HAS TRENDED A BIT
FURTHER SOUTH WITH A SURFACE LOW TRACKING FROM CENTRAL MISSOURI
INTO NORTHEAST INDIANA WHILE THE ECMWF DOES NOT SHOW MUCH OF A
SURFACE CIRCULATION AT ALL. MEANWHILE...THE 23.12Z GEM KEEPS ALL
OF THE SNOW WAY TO THE SOUTH AND NOT EVEN INTO NORTHERN MISSOURI
BY 12Z SUNDAY. WILL HAVE TO CONTINUE TO MONITOR TRENDS WITH THIS
SYSTEM AS THE WEEK PROGRESSES.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1144 AM CST MON FEB 23 2015

A COLD FRONT WILL APPROACH THE AREA FROM THE NORTHERN PLAINS THIS
AFTERNOON INTO TONIGHT. AHEAD OF THE FRONT A STRONG PRESSURE
GRADIENT WILL DEVELOP RESULTING IN GUSTY SOUTH/SOUTHWEST WINDS OF
20 TO 25 KTS WITH GUSTS TO AROUND 32 KTS POSSIBLE.
ALSO...SOUTHWEST WINDS IN THE 2-3KFT LAYER ARE EXPECTED TO
INCREASE TO 50-60 KTS AND MAY CREATE LOW LEVEL WIND SHEAR AT THE
TAF SITES IF SURFACE WINDS LIGHTEN UP A BIT. HAVE MAINTAINED LLWS
IN THE TAFS STARTING AT 03Z AT KLSE AND AT 02Z AT KRST. THE COLD
FRONT LOOKS TO SLIDE INTO THE TAF SITES AFTER 10Z AND MAY GENERATE
A FEW FLURRIES OR POSSIBLY A BRIEF PERIOD OF LIGHT SNOW. HAVE
INCLUDED A PERIOD OF MVFR CONDITIONS AT KLSE STATING AT 11Z.
CONFIDENCE WASN/T HIGH ENOUGH ON SNOW IMPACTING KRST TO HAVE LEFT
IT OUT OF THE RST TAF AT THIS TIME. PLAN ON THE LLWS SUBSIDING
AFTER 10Z.


&&

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

$$

SHORT TERM...HALBACH
LONG TERM...HALBACH
AVIATION...WETENKAMP



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