Area Forecast Discussion
Issued by NWS La Crosse, WI

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FXUS63 KARX 260957
AFDARX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
357 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 WASSAU.

.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/TREMPALEAU/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 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1100 PM CST THU DEC 25 2014

A SFC TROUGH WILL TRACK SLOWLY EASTWARD ACROSS THE REGION
TONIGHT/FRIDAY...WITH AN UPPER LEVEL SHORTWAVE TROUGH SPINNING
ACROSS THE UPPER MISSISSIPPI RIVER VALLEY FRIDAY NIGHT. IFR-MVFR
CIGS ARE LOCATED POST THE SFC TROUGH...AND ANTICIPATE THESE WILL
SPREAD ACROSS KRST TOWARD 10Z...CLOSER TO 12Z FOR KLSE. DECENT
UPGLIDE ON THE LOW LEVEL ISENTROPIC SFCS COULD PRODUCED PATCHY AREAS
OF -DZ/FZDZ IN THE LOW CLOUD LAYER. NOT AS CONFIDENT AS EARLIER WITH
THIS OCCURRING THOUGH...WITH RAP BUFKIT SOUNDINGS AND EVEN THE NAM
NOT AS BULLISH ON THE POSSIBILITIES. WILL PULL MENTION AT KRST AS A
RESULT...AND LET SFC OBS/RADAR TRENDS DICTATE WHETHER IT NEEDS TO BE
ADDED BACK. NAM BUFKIT DOES SUGGEST -DZ COULD MOVE IN FOR THE
AFTERNOON. EXPECT SOME REDUCTIONS OF VSBY WITH LOW
CLOUDS...ESPECIALLY FOR THE HIGHER TERRAIN LOCATION OF KRST.

SNOW WILL SPREAD INTO THE REGION WITH THE SHORTWAVE FRIDAY
NIGHT...CONTINUING THROUGH SATURDAY MORNING. ANTICIPATED
ACCUMULATIONS FROM 1 TO 3 INCHES AT THIS TIME. VSBY RESTRICTIONS SUB
1-2SM WITH THE HEAVIER SNOWS. LIFR/IFR CIGS ALSO LIKELY FOR A PERIOD
BETWEEN 06-18Z SAT.


&&

.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.....RIECK


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