Area Forecast Discussion
Issued by NWS La Crosse, WI

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000
FXUS63 KARX 252057
AFDARX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
257 PM CST SUN JAN 25 2015

.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 257 PM CST SUN JAN 25 2015

CHALLENGES CONCERN PRECIPITATION CHANCES/AMOUNTS/TYPE LATE TONIGHT
THROUGH MONDAY WITH THE NEXT CANADIAN TROUGH MOVING THROUGH
NORTHWEST FLOW ALOFT. 25.12Z MODEL SUITE IN GOOD OVERALL AGREEMENT
WITH PRECIPITATION PLACEMENT...BUT DIFFER SLIGHTLY ON AMOUNTS...
ESPECIALLY EAST OF THE MS RIVER VALLEY. WILL USE A BLENDED
SOLUTION OF THE 25.12Z GFS/NAM/ECMWF/GEM WITH ADDITIONAL SUPPORT
FROM THE LATEST SUITE OF HIGH-RESOLUTION MODEL GUIDANCE.

THIS EVENING WILL BE PARTLY TO MOSTLY CLOUDY AND COOL WITH
TEMPERATURES DROPPING INTO THE LOWER TEENS TO LOWER 20S.
PRECIPITATION WILL HOLD OFF UNTIL AFTER MIDNIGHT WHEN AN 850 HPA
TROUGH OVER CENTRAL MANITOBA/EASTERN DAKOTAS MOVES ACROSS MN AND
INTO THE UPPER MS RIVER VALLEY. MODEST MID-LEVEL WARM AIR
ADVECTION/ISENTROPIC LIFT AND QG CONVERGENCE ALONG FRONTAL
BOUNDARY WILL SLIDE FROM WEST TO EAST ACROSS THE FORECAST AREA
MONDAY MORNING. INITIAL THERMAL/MOISTURE PROFILES ARE COLD ENOUGH
AND SATURATED TO AROUND 500 HPA FOR ALL SNOW. HOWEVER...AS DAY
PROGRESSES...ICE LOSS OCCURS AS 700 TO 500 HPA LAYER DRYS OUT.
WITH SUB-FREEZING BOUNDARY LAYER TEMPERATURES...EXPECT SNOW TO
TRANSITION TO FREEZING DRIZZLE FROM WEST TO EAST THROUGH THE DAY.
SNOW ACCUMULATION WILL BE GREATEST ALONG AND EAST OF A LINE FROM
EAU CLAIRE TO BLACK RIVER FALLS TO PLATTEVILLE WITH 1 TO 2 INCHES.
FARTHER WEST TO THE MS RIVER...A QUICKER CHANGE OVER TO DRIZZLE
WILL KEEP SNOW AMOUNTS GENERALLY IN THE HALF INCH TO AN INCH
RANGE. SNOW WEST OF THE RIVER WILL BE A TRACE TO HALF INCH.

A THIN GLAZE OF ICE FROM FREEZING DRIZZLE IS POSSIBLE MONDAY
MORNING...ESPECIALLY ALONG AND EAST OF THE MS RIVER VALLEY...BUT
BECAUSE THERE IS LIKELY TO BE A SHARP CUT-OFF BETWEEN THE STRONGEST
FORCING/BACK EDGE OF PRECIPITATION AND WHEN ICE LOSS OCCURS...
CONFIDENCE NOT HIGH ENOUGH AT THIS TIME TO HOIST AN ADVISORY.
IMPACTS TO THE MORNING COMMUTE A POSSIBILITY AND CERTAINLY
SOMETHING TO KEEP A CLOSE EYE ON THIS EVENING AND OVERNIGHT. IF
ICE ACCUMULATION DOES HAPPEN...IT SHOULD QUICKLY MELT AS
TEMPERATURES RISE TO ABOVE FREEZING FOR ALL AREAS EXCEPT THE FAR
EAST BEHIND THE WARM FRONT.

.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 257 PM CST SUN JAN 25 2015

LINGERING LIGHT SNOW/FREEZING DRIZZLE WILL PUSH EAST MONDAY NIGHT
WITH DRY CONDITIONS THROUGH TUESDAY AS SURFACE HIGH PRESSURE
BUILDS ACROSS THE REGION. SHOULD SEE SOME SUN BY LATE TUESDAY WITH
TEMPERATURES RISING INTO THE LOWER TO MID 30S.

WEDNESDAY WILL BE DRY AND POTENTIALLY QUITE WARM AS LOW PRESSURE
DRIFTS ACROSS THE REGION AND KEEPS MOST OF THE FORECAST AREA
WITHIN THE WARM SECTOR. PRECIPITATION WILL REMAIN TO THE NORTH
WITH 850 HPA TEMPERATURES ACROSS THE UPPER MS RIVER VALLEY FROM
+2 TO +5 C. CLOUD COVER COULD LIMIT TEMPERATURE RISE...BUT LOWER
40S A REAL POSSIBILITY...ESPECIALLY ACROSS NORTHEAST IA INTO
SOUTHWEST WI. PRECIPITATION CHANCES INCREASE WEDNESDAY NIGHT INTO
THURSDAY AS MID-LEVEL WAVE WRAPS-UP ACROSS WI.

LATE THURSDAY THROUGH SUNDAY...NORTHWEST FLOW ALOFT PERSISTS
ALLOWING A SERIES OF WEAK WAVES TO TRANSLATE ACROSS THE UPPER
MIDWEST. THE STRONGEST OF THESE IMPACTS THE REGION FRIDAY NIGHT
INTO SATURDAY WITH A 20-30 PERCENT CHANCE OF LIGHT SNOW.
TEMPERATURES FOR THE LATTER HALF OF THE WEEK INTO NEXT WEEKEND
WILL DROP SLIGHTLY EACH DAY AS AN ARCTIC TROUGH DROPS SOUTH ACROSS
EASTERN CANADA AND INTO THE EASTERN CONUS. HIGHS IN THE UPPER 20S
TO LOWER 30S ON THURSDAY WILL DROP INTO THE MID TEENS TO LOWER 20S
BY SUNDAY.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1115 AM CST SUN JAN 25 2015

MVFR CONDITIONS LATE THIS MORNING WILL BECOME VFR THIS AFTERNOON
AS STRATUS BECOMES BKN-SCT WITH CLOUD BASES IN THE 4 TO 8 KFT
RANGE. LOOK FOR CLOUDS TO INCREASE TONIGHT AS A WEAK STORM SYSTEM
APPROACHES FROM THE NORTHWEST. LIGHT SNOW IS EXPECTED TO DEVELOP
AT KRST AROUND 10Z WITH VISIBILITIES LOWERING TO AROUND 4SM AND
CEILINGS FALLING TO 600 FT. THE SNOW LOOKS TO PUSH INTO KLSE
AROUND 12Z WITH VISIBILITIES FALLING TO AROUND 2 SM AND CEILINGS
LOWERING TO 1KFT. THE LIGHT SNOW COULD SWITCH OVER TO LIGHT
FREEZING DRIZZLE MONDAY MORNING WITH SOME LIGHT ICE ACCUMULATIONS
POSSIBLE. PLAN ON IFR/LIFR CONDITIONS FOR MONDAY MORNING AS THIS
SYSTEM MOVES THROUGH.


&&

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

$$

SHORT TERM...ROGERS
LONG TERM...ROGERS
AVIATION...WETENKAMP



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