794
FXUS63 KARX 051139
AFDARX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
539 AM CST FRI DEC 5 2025
KEY MESSAGES
- LIGHT SNOW EXPECTED TODAY WITH SOME LOCATIONS POTENTIALLY
(30-80%) REACHING AN INCH OF ACCUMULATION NORTH OF I-90. SMALL
(15-20%) CHANCE FOR BRIEF FREEZING DRIZZLE IN CENTRAL WI
BEFORE PRECIP ENDS THIS EVENING.
- MORE NOTABLE SNOW POSSIBLE SATURDAY NIGHT WITH A DECENT
(25-50%) CHANCE FOR AT LEAST 4" OF ACCUMULATION IN NORTHEAST
IOWA.
- MULTIPLE PERIODS WITH SNOW POTENTIAL NEXT WEEK.
- COLD, WINTRY TEMPERATURES CONTINUE OVER THE NEXT 7 DAYS.
DISCUSSION
ISSUED AT 344 AM CST FRI DEC 5 2025
LIGHT SNOW TODAY, LOW POTENTIAL FOR FREEZING DRIZZLE
TODAY, UPPER WAVE OVER THE DAKOTAS AS OF 08Z SWINGS
SOUTHEASTWARD, PASSING OVER LAKE MICHIGAN AROUND 06Z SATURDAY.
IN THE INTERIM, THIS SHOULD PROVIDE ENOUGH LIFT TO GENERATE
LIGHT SNOW ACROSS A GOOD PORTION OF THE CWA, PARTICULARLY NORTH
OF A LATITUDE DEFINED BY THE IA/MN BORDER. ASIDE FROM THE UPPER
DISTURBANCE, FORCING FOR ASCENT IS WEAK AND SO THINKING MOST
AREAS WILL ONLY SEE MINOR ACCUMULATIONS, WITH POTENTIAL (30-80%
PER 09.00Z HREF) FOR AN INCH ALONG AND NORTH OF I-90 WITH BEST
CHANCES IN CLARK/TAYLOR COUNTIES AND NORTHERN
BUFFALO/TREMPEALEAU/JACKSON.
OF NOTE, PROGGED SOUNDINGS IN HRRR/RAP SUGGEST THAT WEST
CENTRAL WI MAY SEE A BRIEF PERIOD WHERE SATURATION IN THE DGZ IS
LOST WHILE ASCENT IN THE LOW LEVELS CONTINUES THIS EVENING.
SHOULD THIS OCCUR, A BRIEF PERIOD OF FREEZING DRIZZLE WOULD
RESULT. HOWEVER, SIGNAL FOR CONTINUED ASCENT IN THE SATURATED
NEAR-SURFACE LAYER HAS NOT BEEN CONSISTENT BETWEEN RUNS OF
SHORT-TERM GUIDANCE AND, IN ANY CASE, FZDZ WOULD OCCUR FOR ONLY
AN HOUR OR TWO, SO CURRENT THINKING IS THAT POTENTIAL FOR
IMPACTS IS LOW (15-20%).
SNOW SATURDAY NIGHT
SATURDAY INTO SATURDAY NIGHT, STRONGER SHORTWAVE DIVES
SOUTHEAST FROM MT TO E IA. STRONGER FORCING WITH THE WAVE ITSELF
AND POTENTIAL FOR AN AXIS OF 850MB FRONTOGENESIS SHOULD LEAD TO
HIGHER SNOW TOTALS COMPARED TO FRIDAY'S SNOW, WITH REMAINING
QUESTIONS FOCUSING ON WHERE EXACTLY MODERATE TO HEAVY SNOW WILL
OCCUR AND HOW FAR NORTH THIS WILL SPREAD. 09.00Z GEFS/EPS ARE IN
RELATIVE ALIGNMENT AND FOCUS HEAVIEST SNOWS - PERHAPS UPWARDS
OF 6" - IN CENTRAL IA TO THE SOUTH OF OUR CWA. TAKING A LOOK AT
PROBABILITIES TO REACH 3", THESE ARE GENERALLY 35-90% ALONG AND
SOUTHWEST OF A LAKE CITY MN TO LA CROSSE TO PLATTEVILLE WI LINE.
GEFS/EPS DISAGREEMENT FOCUSES ON HOW FAR NORTH/EAST IMPACTFUL
SNOWS WILL OCCUR, WITH A BIT HIGHER PROBABILITY THAT THESE COULD
OCCUR AS FAR NORTHEAST AS I-94. GIVEN STRONG CYCLE TO CYCLE
CONTINUITY SEEN IN THE EPS, AM LEANING TOWARD THIS SOLUTION FOR
NOW. IN ANY CASE, INTERESTS IN NE IA COULD VERY WELL (25-50%)
SEE AN ADDITIONAL 4" OF SNOW.
PERIODIC SNOW NEXT WEEK
PERSISTENT NORTHWEST FLOW ALOFT WILL KEEP THE AREA VULNERABLE
TO ADDITIONAL SNOW FROM CLIPPER SYSTEMS BEYOND SATURDAY NIGHT.
OPERATIONAL 05.00Z RUNS SUGGEST TWO CLIPPERS WILL OCCUR
SOMEWHERE IN THE UPPER MIDWEST IN QUICK SUCCESSION TUESDAY NIGHT
AND THEN AGAIN WEDNESDAY NIGHT INTO THURSDAY BUT DISAGREE ON
PLACEMENT AND EXACT TIMING. GIVEN THE WIDE RANGE OF CLIPPER
TRAJECTORIES AND TIMINGS SEEN ACROSS OPERATIONAL AND ENSEMBLE
GUIDANCE, HAVE ELECTED TO STICK WITH BLENDED GUIDANCE VALUES
WHICH ARE BROADLY ILLUSTRATIVE OF THE PERIODIC SNOW POTENTIAL
NEXT WEEK.
COLD CONTINUES
THE CALENDAR FLIPPED OVER TO DECEMBER A FEW DAYS AGO, THE FIRST
MONTH OF METEOROLOGICAL/CLIMATOLOGICAL WINTER, AND TEMPERATURES
HAVE CERTAINLY REFLECTED THAT AND THEN SOME, REMAINING WELL
BELOW NORMAL FOR EARLY DECEMBER. THIS CONTINUES OVER THE NEXT
WEEK WITH THE BEST SHOT (40-70% PER 09.07Z NBM) AT SUBZERO LOWS
APPEARING TO CENTER ON SUNDAY NIGHT INTO MONDAY MORNING, WHEN A
POST FRONTAL SURFACE HIGH AND CONCOMITANT CLEAR SKIES AND LIGHT
WINDS LOOK TO BECOME CENTERED IN OUR CWA AROUND MIDNIGHT.
RELATIVE RELIEF MAY OCCUR TUESDAY AFTERNOON, WHEN TEMPERATURES
COULD (20-60%) REACH ABOVE FREEZING BRIEFLY. HOWEVER, WITH
NORTHWESTERLY FLOW ALOFT CONTINUING FOR AT LEAST THE NEXT 7 DAYS
(HINTS AT A CENTRAL CONUS RIDGE SEEN A COUPLE DAYS AGO HAVE
VANISHED), A NOTABLE WARM UP IS NOT EXPECTED.
AVIATION /12Z TAFS THROUGH 12Z SATURDAY/
ISSUED AT 539 AM CST FRI DEC 5 2025
VFR CONDITIONS GIVE WAY TO IFR CONDITIONS LATE THIS MORNING AS A
DISTURBANCE WILL BRING LIGHT SNOW NEAR AND NORTH OF I-90 FOR MUCH OF
THE AFTERNOON TODAY. CONSEQUENTLY, PROBABILITIES FOR IFR CIGS AND
VSBYS INCREASE DRAMATICALLY (40-70% CHANCE) BY AROUND 16-18Z. MUCH
OF THE CAMS GENERALLY KEEP SNOW CONTINUING THROUGH MUCH OF THE
AFTERNOON BEFORE EXITING TO THE EAST DURING THE EVENING HOURS.
OVERALL SNOW ACCUMULATIONS GENERALLY WILL BE AROUND AN INCH OR LESS
NEAR AND NORTH OF THE I-90 CORRIDOR. CANNOT RULE OUT (~20% CHANCE) A
VERY BRIEF PERIOD OF FZDZ ACROSS PORTIONS OF WEST-CENTRAL WI LATE
THIS AFTERNOON AND EVENING AS SNOW EXITS. WINDS WILL BEGIN THE TAF
PERIOD FROM THE SOUTH AT AROUND 8-12 KTS BUT WILL SHIFT TO
NORTHWESTERLY WITH A FRONTAL PASSAGE THIS EVENING.
ARX WATCHES/WARNINGS/ADVISORIES
WI...NONE.
MN...NONE.
IA...NONE.
DISCUSSION...FERGUSON
AVIATION...NAYLOR
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