452
FXUS63 KARX 241737
AFDARX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
1137 AM CST WED DEC 24 2025
KEY MESSAGES
- WARM FOR THE REST OF THE WEEK WITH HIGHS RUNNING 10-15 DEGREES
ABOVE NORMAL, BUT COLDER AIR LURKS ON THE HORIZON FOR SUNDAY
AND MONDAY WITH TEMPERATURES FALLING BY 20-25 DEGREES.
- INCREASING CLOUDS THIS AFTERNOON WITH LIGHT DRIZZLE MAINLY
ALONG AND SOUTH OF I-90 INTO THE EVENING.
- THERE IS AN INCREASING RISK FOR FREEZING RAIN (40-60% CHANCE)
NORTH OF I-90 AND EAST OF THE MISSISSIPPI RIVER FOR THURSDAY
NIGHT, WHICH COULD MAKE FOR SLIPPERY CONDITIONS FOR ANY POST-
HOLIDAY TRAVEL.
DISCUSSION
ISSUED AT 225 AM CST WED DEC 24 2025
TODAY/TONIGHT: INCREASING CLOUDS AND DRIZZLE
A BLOCKING LONGWAVE RIDGE REMAINS THE DOMINANT FEATURE OF NOTE
ACROSS THE CENTRAL CONUS THIS MORNING, THOUGH WITH THE UPSTREAM
AXIS AMPLIFYING, A WEAK VORT LOBE RIDES DOWN THE RIDGE AND WILL
BE THE DRIVER FOR OUR SENSIBLE WEATHER LATER TODAY. AS THIS
WAVE APPROACHES THIS MORNING, INCREASING SOUTHWESTERLY FLOW
ACROSS THE LOWER MISSOURI RIVER VALLEY AND INTO THE LOCAL REGION
SHOULD ADVECT A SATURATED LOWER TROPOSPHERIC AIRMASS (NOTED AS
FOG/LOW STRATUS ACROSS KANSAS AND CENTRAL MISSOURI EARLY THIS
MORNING) NORTHWARD AND INTO PARTS OF THE REGION LATER TODAY.
MID-TROPOSPHERIC WINDS SHOULD START TURNING MORE WESTERLY THIS
EVENING AS THE UPPER LEVEL PERTURBATION SCOOTS ON THROUGH, SO
THE BEST LIFT AND DEEPEST SATURATION OF >1-KM IN DEPTH WILL NOT
LINGER ALL THAT LONG. THE GREATEST PROBABILITIES FOR DRIZZLE
WILL THEREFORE BE ALONG AND SOUTH OF I-90, MAINLY IN NORTHEAST
IOWA AND SOUTHWEST WISCONSIN. IMPACTS SHOULD BE MINIMAL WITH
TEMPERATURES WELL ABOVE FREEZING IN A WARM AIR ADVECTION REGIME.
THE LOW LEVEL MOISTURE LOOKS TO HANG UP MAINLY ALONG AND SOUTH
OF I-90 AND WEST OF THE MISSISSIPPI RIVER TONIGHT, WHICH COULD
SET THE STAGE FOR DENSE FOG DEVELOPMENT. THE EXACT COVERAGE AND
THICKNESS OF THE FOG IS LESS CERTAIN GIVEN THAT WEAK NEGATIVE
THETA-E ADVECTION WILL BE ONGOING THROUGH THE BOUNDARY LAYER,
WHICH MAY LIMIT THE AREAL EXTENT OF THE FOG OR ERODE IT OVER
TIME.
THURSDAY NIGHT - FRIDAY MORNING: WINTRY MIX POTENTIAL
THE NEXT NOTABLE CHANCE OF PRECIPITATION POSES A CHALLENGE TO
THE FORECAST WITH REGARDS TO THE EXTENT OF FREEZING RAIN/DRIZZLE
THURSDAY NIGHT INTO FRIDAY MORNING. DOWNSTREAM SURFACE HIGH
PRESSURE WILL STILL BE DEPARTING AS 290K ISENTROPIC ASCENT AND
THETA-E ADVECTION INCREASE THROUGH THE EVENING HOURS ON
THURSDAY. LIGHT RAIN (MAYBE MORE OF A HEAVY DRIZZLE?) IS LIKELY
FOR MOST LOCALES AT SOME POINT IN THE EVENING/OVERNIGHT, SO THE
FREEZING RAIN THREAT HINGES HEAVILY ON TEMPERATURE TRENDS
THROUGH THE DAY AND EVENING TOMORROW.
SOME EARLY LOOKS AT THE LONGER RANGE CAMS ARE MIRRORING THE
GENERAL CONSENSUS OF THE GLOBAL MODELS WITH PLACING THE
GREATEST RISK FOR LIGHT ICE ACCRETION ALONG AND NORTHEAST OF THE
I-94 CORRIDOR WHERE EASTERLY FLOW WILL BE MOST ESTABLISHED AND
TEMPERATURES STRUGGLE TO REACH FREEZING DURING THE DAY. LOWER
PROBABILITIES FOR A BRIEF BOUT OF FREEZING RAIN (<10%) EXTEND AS
FAR SOUTHWEST AND LA CROSSE AND ROCHESTER, BUT THE IMPACTS IN
THESE AREAS SHOULD BE MITIGATED BY STEADY TEMPERATURES AROUND
FREEZING THAT WARM AFTER MIDNIGHT.
WHILE OVERALL QPF AMOUNTS ARE LIGHT GIVEN THE DISJOINTED NATURE
OF THE SYSTEM, ANY FREEZING PRECIPITATION THAT FALLS DURING
THIS OVERNIGHT PERIOD COULD QUICKLY LEAD TO TRAVEL IMPACTS,
ESPECIALLY ALONG I-94.
FRIDAY - SATURDAY: WARM!
WITH THE OVERALL PATTERN AMPLIFYING THROUGH THE END OF THE WEEK
AND THE FLOW TURNING MORE TO THE SOUTHWEST, FRIDAY AND SATURDAY
FEATURE OUR WARMEST TEMPERATURES OF THE PERIOD WITH MANY
LOCALES CRACKING THE 40-45 DEGREE MARK. IN FACT, ABOUT 10-20% OF
THE NBM ENSEMBLE MEMBERS HAVE AREAS ALONG THE SAME LATITUDE AS
DUBUQUE CLOSING IN ON 50 DEGREES ON FRIDAY, SPREADING AS FAR
NORTH AS I-90 FOR SATURDAY.
SUNDAY - MONDAY: WINTER TEMPERATURES RETURN
A SHARP LONGWAVE TROUGH FINALLY CUTS THROUGH THE RIDGE LATE
SATURDAY AND A STRONG COLD FRONT RACES THROUGH THE REGION
SATURDAY NIGHT INTO SUNDAY MORNING, SENDING TEMPERATURES
TUMBLING INTO THE SINGLE DIGITS FOR LOWS BY MONDAY MORNING.
WHETHER WE SEE ANY PRECIPITATION WITH THIS COLD FRONTAL PASSAGE
IS A LOWER CONFIDENCE ASPECT OF THIS FORECAST DEPENDENT ON HOW
QUICKLY THE ATTENDANT SURFACE CYCLONE CAN MATURE. TRENDS OVER
THE LAST 24 HOURS HAVE SHOWN AN INCREASE IN THE PROBABILITIES
(NOW UP TO 20-40%) FOR LIGHT SNOW IN THE POST-FRONTAL AIRMASS
DURING THE DAY ON SUNDAY.
MODERATING TEMPERATURES DO ARRIVE BY TUESDAY AND WEDNESDAY, BUT
TO WHAT EXTENT TEMPERATURES REBOUND IS QUITE UNCERTAIN GIVEN
HOW THE REGION WILL RESIDE ALONG THE TRANSITION ZONE BETWEEN A
TEMPERATE AND POLAR AIRMASS ON THE DOWNSTREAM FLANK OF A
SHARPER RIDGE. IN FACT, THE NBM HAS A NEARLY 40 DEGREE SPREAD
IN THE HIGH TEMPERATURE FORECAST BY MIDWEEK!
AVIATION /18Z TAFS THROUGH 18Z THURSDAY/
ISSUED AT 1121 AM CST WED DEC 24 2025
LOW-LEVEL MOISTURE CONTINUES TO INCREASE ACROSS THE AREA THIS
AFTERNOON AS CEILINGS BECOME MVFR FROM THE SW TO NE/ THESE
CEILINGS ARE ALREADY OCCURRING ALONG AND EAST OF I35 CORRIDOR.
EXPECT CEILINGS TO CONTINUE TO FALL WEST OF THE MISSISSIPPI
RIVER TONIGHT INTO LOW-END MVFR AND IFR, WITH A 30% CHANCE FOR
A BRIEF PERIOD OF LIFR. A BRIEF WINDOW OF FOG DEVELOPING WEST OF
THE RIVER IS POSSIBLE (20-30%), BUT MOST LIKELY SOLUTION IS FOR
LOW STRATUS RATHER THAN FOG. HEADING INTO THURSDAY FLIGHT
CATEGORIES IMPROVE INTO VFR FOR MUCH OF THE AREA THROUGH THE
DAY, BUT MVFR/IFR CEILINGS WILL REMAIN PRIMARILY ALONG AND WEST
OF US63.
ARX WATCHES/WARNINGS/ADVISORIES
WI...NONE.
MN...NONE.
IA...NONE.
DISCUSSION...SKOW
AVIATION...JAW
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