Area Forecast Discussion
Issued by NWS La Crosse, WI

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000
FXUS63 KARX 261130
AFDARX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
530 AM CST FRI DEC 26 2014

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 357 AM CST FRI DEC 26 2014

CHALLENGES SURROUND SNOW CHANCES AND AMOUNTS TONIGHT INTO
SATURDAY WITH THE NEXT LOW PRESSURE SYSTEM. 26.00Z MODEL SUITE IN
GOOD AGREEMENT WITH THE SURFACE LOW TRACK...BUT DIFFER SOMEWHAT ON
THE PLACEMENT AND TIMING OF THE HIGHEST QPF. WILL LEAN TOWARD A
NAM/ECMWF BLEND WITH SUPPORT FROM THE SREF WHICH BEST MATCH
PRECIPITATION PLACEMENT WITH THE STRONGEST MID-LEVEL FORCING.

MAJORITY OF PRECIPITATION TODAY WILL REMAIN NORTH OF THE FORECAST
AREA ALONG TIGHT 850 TO 700 HPA THERMAL GRADIENT. ANYTHING THAT
DOES CREEP FAR ENOUGH SOUTH WILL LIKELY FALL AS DRIZZLE GIVEN WEAK
LIFT AND A DRY PROFILE ABOVE 1 TO 2 KM. TODAY WILL BE THE LAST
RELATIVELY MILD DAY FOR AWHILE WITH TEMPERATURES IN THE MID 30S
TO LOWER 40S.

PRECIPITATION EXPECTED TO DEVELOP RAPIDLY THIS EVENING AND
OVERNIGHT AS A SOUTHERN ROCKIES SHORT-WAVE MOVES INTO THE UPPER
MIDWEST AND INTERACTS WITH A SECONDARY WAVE DROPPING SOUTH ACROSS
THE SOUTHERN CANADIAN PRAIRIES. ASSOCIATED SURFACE LOW ACROSS
NORTHERN MO AT 27.06Z WILL RAPIDLY MOVE NORTH INTO SOUTHERN WI
SIX HOURS LATER. COLUMN TO QUICKLY SATURATE AND EXPECT DEFORMATION
PRECIPITATION AXIS FROM NORTHWEST IA INTO SOUTH-CENTRAL/SOUTHEAST
MN AND THEN INTO WEST-CENTRAL/NORTHERN WISCONSIN. THERMAL PROFILE
WILL BE COLD ENOUGH FOR ALL SNOW. LOWER SNOW RATIOS INITIALLY TO
RISE TO AROUND 14:1 BY SATURDAY MORNING WITH COOLING COLUMN. WITH
QPF AROUND TWO TO THREE TENTHS...EXPECT SNOW AMOUNTS TONIGHT
AROUND 1 TO 3 INCHES ALONG AND NORTHWEST OF A LINE FROM DODGE
CENTER TO WINONA TO WAUSAU.

.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 357 AM CST FRI DEC 26 2014

LIGHT SNOW TO CONTINUE SATURDAY MORNING WITH AN ADDITIONAL 1 TO 2
INCHES POSSIBLE. WILL ISSUE A TWO-PART WINTER WEATHER ADVISORY FOR
2 TO 4 INCHES OF STORM TOTAL SNOW TONIGHT INTO SATURDAY. THE
FIRST PART INCLUDES DODGE/OLMSTED/WABASHA COUNTIES FROM 27.00Z TO
28.15Z AND THE SECOND PART FOR BUFFALO/TREMPEALEAU/JACKSON/TAYLOR/
CLARK COUNTIES FROM 27.03Z TO 28.18Z. A TIGHT GRADIENT IN
SNOWFALL IS EXPECTED FROM NORTH TO SOUTH ACROSS THESE COUNTIES
WITH SLICK ROAD CONDITIONS POSSIBLE THROUGH THE EVENT. COLD FRONT
TO DROP ACROSS THE FORECAST AREA SATURDAY BEGINNING THE DECLINE IN
TEMPERATURES WITH HIGHS 5 TO 8 DEGREES COLDER THAN TODAY.
NORTHWEST WIND TO PICK-UP BEHIND THE FRONT WITH OCCASIONAL GUSTS
TO 20 MPH. LINGERING LIGHT SNOW TO EXIT THE AREA BY SATURDAY
EVENING.

SUNDAY THROUGH THURSDAY...SYNOPTIC REGIME SHIFTS TO DRIER
NORTHWEST FLOW ALOFT AS A BROAD TROUGH TAKES UP RESIDENCE ACROSS
HUDSON BAY. THIS BRINGS LOW SNOW CHANCES MONDAY AND AGAIN THURSDAY
AS SHORT-WAVES ROTATE AROUND THE PARENT TROUGH...BUT NOT EXPECTING
ANY SIGNIFICANT ACCUMULATIONS. BIGGER STORY WILL BE MUCH COLDER
CONDITIONS. TEMPERATURES TO DROP DAILY AND BOTTOM OUT ON TUESDAY
WITH HIGHS IN THE SINGLE DIGITS TO TEENS ABOVE ZERO. ASSUMING SOME
DEGREE OF CLEARING...MANY LOCATIONS TUESDAY/WEDNESDAY MORNINGS
LIKELY TO DROP BELOW ZERO. TEMPERATURES WILL MODERATE SOMEWHAT BY
LATE WEEK WITH HIGHS BACK INTO THE 20S AND LOWS IN THE SINGLE
DIGITS.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 530 AM CST FRI DEC 26 2014

A WEAK SFC-850MB FRONTAL BOUNDARY  WAS STALLED OVER THE AREA EARLY
THIS MORNING. IFR CLOUDS WEST OF THE FRONT REMAINED WEST OF THE TAF
SITES EARLY THIS MORNING. UNDER CLEAR SKIES/LIGHT WINDS ALONG/EAST
OF THE FRONT...PATCHY BR/VALLEY FOG PLAGUING LOCATIONS ALONG/EAST OF
THE MS RIVER LIKE KLSE WITH SCT MVFR/IFR VSBYS. THIS TO CONTINUE
UNTIL THE FRONT PUSHES EAST THIS MORNING AND WINDS BECOME NORTH
BEHIND IT.

THE IFR STRATUS WILL SPREAD WEST TO EAST ACROSS THE AREA LATER THIS
MORNING BEHIND THE FRONT...EXPECTED TO REACH KRST AROUND 15Z AND
KLSE AROUND 18Z. IFR CIGS TO THEN PERSIST THRU TONIGHT INTO SAT. LOW
PRESSURE LIFTING NORTHEAST ACROSS IA INTO SOUTHERN WI TONIGHT WILL
SPREAD A BAND OF SNOW ACROSS THE TAF SITES TONIGHT...WITH VSBYS
DROPPING TO IFR IN THE SNOW. THIS EXPECTED TO REACH KRST AROUND MID
EVENING...THEN KLSE AROUND MIDNIGHT TONIGHT AND CONTINUE INTO SAT
MORNING. A COUPLE OF INCHES OF SNOW ARE EXPECTED AT BOTH KRST/KLSE
TONIGHT INTO SAT MORNING.

&&

.ARX WATCHES/WARNINGS/ADVISORIES...
WI...WINTER WEATHER ADVISORY FROM 9 PM THIS EVENING TO NOON CST
     SATURDAY FOR WIZ017-029-032>034.

MN...WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO 9 AM CST
     SATURDAY FOR MNZ079-086-087.

IA...NONE.
&&

$$

SHORT TERM...ROGERS
LONG TERM....ROGERS
AVIATION.....RRS


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