Area Forecast Discussion
Issued by NWS La Crosse, WI

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000
FXUS63 KARX 232002
AFDARX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
202 PM CST TUE DEC 23 2014

.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 202 PM CST TUE DEC 23 2014

FORECAST CHALLENGES INCLUDE LINGERING LIGHT PRECIPITATION TONIGHT
INTO WEDNESDAY AND THEN LOW-END PRECIPITATION CHANCES AGAIN
FRIDAY/FRIDAY NIGHT. 23.12Z GFS/NAM/ECMWF/GEM ARE IN GOOD
AGREEMENT THROUGH 26.12Z...DIVERGING SOMEWHAT THEREAFTER WITH THE
LATE WEEK SYSTEM. WILL USE A BLENDED MODEL SOLUTION.

FOR TONIGHT...SURFACE LOW CURRENTLY ACROSS CENTRAL WI WILL QUICKLY
EJECT INTO SOUTHEAST ONTARIO. DEFORMATION PRECIPITATION AXIS WILL
CONTINUE TO DISSIPATE ACROSS THE FORECAST AREA...BUT WITH MODEL
SOUNDINGS SUGGESTING A LOSS OF ICE IN THE CLOUD...WILL TRANSITION
FROM RAIN/SNOW THIS EVENING TO MAINLY DRIZZLE AFTER MIDNIGHT.
SURFACE TEMPERATURES WILL HOVER RIGHT AROUND THE FREEZING
MARK...SO THERE COULD BE SOME PATCHY ICING FOR ANY AREA THAT
EXPERIENCES MORE CONTINUOUS DRIZZLE. OTHERWISE...CONDITIONS SHOULD
GRADUALLY IMPROVE WITH ONLY MINOR ADDITIONAL SNOW ACCUMULATION.

A STRONG SECONDARY SURFACE LOW WILL SURGE NORTHWARD AND ACROSS
MICHIGAN ON WEDNESDAY AS THE PRIMARY TROUGH ALOFT LIFTS INTO THE
GREAT LAKES REGION. THE PRECIPITATION SHIELD WITH THIS SYSTEM
WILL PRIMARILY IMPACT IL/EASTERN WI AND INTO IN/MI...BUT ITS
WESTERN FLANK COULD CLIP THE EASTERN FORECAST AREA. MOST OF
WEDNESDAY WILL BE DRY...BUT KEPT 20 POPS EAST OF THE MISSISSIPPI
RIVER FOR SOME LIGHT SNOW AND POSSIBLE ACCUMULATIONS AROUND A
TENTH OR TWO. OTHERWISE...WEDNESDAY WILL BE CLOUDY WITH A MODEST
NORTHWEST BREEZE AND TEMPERATURES TOPPING OUT IN THE MID 30S.

.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 202 PM CST TUE DEC 23 2014

CHRISTMAS DAY WILL BE MOSTLY CLOUDY...BUT DRY AS A SURFACE RIDGE
MOVES ACROSS THE UPPER MISSISSIPPI RIVER VALLEY. NO REAL CHANGE IN
AIR MASS...SO TEMPERATURES WILL REMAIN STEADY IN THE 30S.

THE NEXT PACIFIC TROUGH DIGS INTO THE SOUTHERN ROCKIES CHRISTMAS
NIGHT INTO FRIDAY WITH ITS SURFACE LOW MOVING FROM THE LEE OF THE
ROCKIES INTO THE UPPER MIDWEST. PRECIPITATION EXPECTED ALONG THE
850 TO 700 HPA THERMAL GRADIENT...BUT DIFFERENCES ARISE CONCERNING
ITS PLACEMENT. 23.12Z ECMWF/GEM KEEP MAJORITY OF PRECIPITATION
NORTH OF THE FORECAST AREA...WHERES THE GFS/NAM ARE A BIT MORE
BULLISH ON LIGHT QPF...ESPECIALLY FRIDAY AFTERNOON AND EVENING.
TRIMMED POPS ACROSS THE SOUTH ON FRIDAY...BUT KEPT 20-30 POPS
REGION-WIDE FRIDAY NIGHT FOR SOME LIGHT SNOW.

SATURDAY THROUGH TUESDAY WILL BE MOSTLY DRY AS A NORTHWEST FLOW
SYNOPTIC REGIME SETS-UP ACROSS THE UPPER MIDWEST. A COUPLE LIGHT
SNOW EPISODES ARE POSSIBLE...BUT DIFFERENCES IN TIMING AND
STRENGTH OF SHORT-WAVES ROTATING AROUND THE PARENT HUDSON BAY
TROUGH LENDS ITSELF TO LOW CONFIDENCE AND ONLY 20 POPS MONDAY/
MONDAY NIGHT. BIGGER STORY WILL BE MUCH COOLER TEMPERATURES WITH
DAILY HIGHS IN THE UPPER TEENS AND 20S AND NIGHTTIME LOWS IN THE
SINGLE DIGITS TO TEENS.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1117 AM CST TUE DEC 23 2014

LIFR TO IFR CONDITIONS WILL PERSIST AT THE TAF SITES THIS
AFTERNOON IN LOW STRATUS...FOG...AND LIGHT SNOW. PLAN ON
VISIBILITIES BEING REDUCED INTO THE 1-2 SM RANGE WITH CEILINGS
MAINLY IN THE 400 TO 700 FT RANGE. LOW PRESSURE LIFTS NORTHEAST OF
THE AREA TONIGHT BUT LOW STRATUS WILL PERSIST AT THE TAF SITES.
ALSO...IF LIGHT PRECIPITATION LINGERS TONIGHT WE COULD SEE SOME
LIGHT FREEZING DRIZZLE MAINLY AFTER MIDNIGHT INTO EARLY WEDNESDAY
MORNING. PLAN ON IFR CONDITIONS THROUGH THE OVERNIGHT HOURS INTO
WEDNESDAY MORNING WITH LIFR CONDITIONS POSSIBLE AT KRST.


&&

.ARX WATCHES/WARNINGS/ADVISORIES...
WI...WINTER WEATHER ADVISORY UNTIL 6 PM CST THIS EVENING FOR WIZ017-
     029-032>034.

MN...WINTER WEATHER ADVISORY UNTIL 6 PM CST THIS EVENING FOR MNZ079-
     086>088-094-095.

IA...WINTER WEATHER ADVISORY UNTIL 6 PM CST THIS EVENING FOR IAZ008.

&&

$$

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


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