048
FXUS63 KARX 272332
AFDARX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
532 PM CST SAT DEC 27 2025
KEY MESSAGES
- POTENT WINTER STORM SET TO BRING SEVERAL INCHES OF SNOW, NORTHWEST
WINDS GUSTING TO 45 MPH, WIDESPREAD BLOWING AND DRIFTING SNOW TO THE
REGION SUNDAY INTO MONDAY MORNING. WINTER STORM WARNINGS AND
ADVISORIES ARE IN EFFECT. SIGNIFICANT IMPACTS TO TRAVEL, ESPECIALLY
SUNDAY NIGHT. ALTER OR CANCEL PLANS IF CONDITIONS WARRANT IT.
DISCUSSION
ISSUED AT 250 PM CST SAT DEC 27 2025
> SUNDAY-MON MORNING: A HIGH IMPACT WINTER STORM PROMISING VERY
STRONG WINDS, SNOW, AND PLUMMETING TEMPS. TRAVEL SUNDAY NIGHT WILL
RANGE FROM SLIPPERY TO DANGEROUS. BE READY TO ADJUST, DELAY OR
CANCEL TRAVEL PLANS IF CONDITIONS WARRANT IT.
- OVERVIEW: A PAC NW SHORTWAVE SET TO MOVE ACROSS THE PLAINS SUN
MORNING, PICKING UP A BIT OF ENERGY OUT OF THE DESERT SOUTHWEST. THE
SYSTEM STRENGTHENS AS IT LIFTS EAST/NORTHEAST ACROSS THE WESTERN
GREAT LAKES BY SUN EVENING, THANKS IN PART TO AN APPROX 150 KT 300
MB JET STREAKING ACROSS IA/IL.
ITS BEEN QUITE AN EVOLUTION TO THIS WINTER STORM OVER THE PAST
SEVERAL DAYS AS THE GEFS AND EPS SUITES HAVE STRENGTHEN, SLOWED THE
SYSTEM DOWN ALMOST ON A RUN-TO-RUN BASIS. THE EPS CONTINUES TO
SUGGEST THIS STRENGTHENING TREND COULD PERSIST WITH THE MAJORITY OF
ITS MEMBERS FARTHER SOUTHWEST, A TAD STRONGER THAN THE MEAN.
THAT SAID, BOTH THE EPS AND GEFS SEEM TO HAVE SETTLED IN ON A TRACK
FOR THE SFC LOW, ADVANCING IT FROM NORTHERN MO TO THE NORTHEAST
CORNER OF IL BY 21Z SUN.
THE STORM LIFTS MORE NORTH SUN NIGHT BEFORE HEADING BACK EAST ON
MON. THIS ROTATES BITS OF SHORTWAVE ENERGY WESTWARD WHILE ALSO
LINGERING A SFC TROUGH AND THE DEFORMATION REGION OVER NORTHERN WI
INTO MON MORNING.
- PRECIPITATION: BROAD LOW LEVEL THERMODYNAMICS WORK ON LOW
SATURATION TONIGHT, PRODUCING PATCHY TO AREAS OF DRIZZLE INTO SUN
MORNING. THIS SHIFTS EAST WITH DEEPENING SATURATION MOVING IN FROM
THE WEST ACCOMPANIED BY A BLOSSOMING DEFORMATION REGION. THIS REGION
PIVOTS, BECOMES A BIT MORE WEST-EAST IN ORIENTATION SUN NIGHT ACROSS
NORTHERN WI, GRADUALLY EXITING EAST BY MID MORNING MON.
INITIALLY RAIN, THE PCPN WILL TRANSITION TO A WINTRY MIX THEN JUST
SNOW FROM WEST TO EAST AS COLD AIR FLOWS IN FROM THE NORTH/NORTHWEST.
NOT SEEING MUCH/IF ANY THREAT FOR FREEZING PCPN THIS GO AROUND AS BY
THE TIME SFC TEMPS REACH FREEZING THERE LOOKS TO BE ICE IN THE
CLOUD.
LATEST OUTLAY OF SNOW TOTALS DROPS 5 TO 8" ALONG/NORTH OF I-90.
SOUTH OF THERE IT DROPS OFF TO 2 TO 4". TIME AND RESIDENCE AIDING
THE TOTALS IN THE NORTH. ALSO, NATURE OF THE SNOW WILL WORK ON
AMOUNTS - STARTING OUT WET, GRADUALLY TRENDING DRIER MOVING INTO THE
NIGHT. IN ADDITION, THE STRONG WINDS WILL SHATTER ANY LARGER
DENDRITES - WHICH WOULD BE ANOTHER LIMITER TO HIGH END RATIOS. LOWER
RATIOS A BIT WITH BOTH FACTORS IN MIND. EXPECT MORE ADJUSTMENTS AS
WE MOVE INTO SUNDAY.
- WIND: WINDS START TO RAMP UP SUN AFTERNOON AS SFC LOW MOVES OVER
NORTHERN IL AND PRESSURE GRADIENT TIGHTENS. WIND CONTINUES TO
INCREASE MOVING INTO SUN NIGHT WITH A 50 KT 850 MB JET DRIVING
SOUTHEAST ACROSS THE FORECAST AREA. WHILE THE MIXED LAYER MAY NOT
REACH THAT DEEP INTO THE ATMOSPHERE, RAP AND HRRR BUFKIT SOUNDINGS
SUGGEST 50KTS WILL BE FOUND BY 2.5-3 KFT, AND WITH UNIDIRECTIONAL
WINDS IN THAT LAYER, MOMENTUM TRANSFER COULD BRING MUCH OF THAT TO
THE SFC. LATEST HREF PAINTS 60-80% CHANCES FOR 40+ MPH GUSTS
ALONG/WEST OF THE MISSISSIPPI RIVER SUN EVENING. THE EPS IS SIMILAR
AND ALSO GIVES A 30 TO 50% SHOT FOR 45+ MPH GUSTS IN THE SAME
LOCATIONS.
DEPENDING ON HOW QUICKLY CURRENT SNOW COVER CAN "CRUST" OVER,
EVOLUTION OF THE SNOW TYPE (FROM WET TO DRY), AND WHERE THE HIGHER
AMOUNTS ARE REALIZED, THESE STRONG WINDS COULD/WOULD PRODUCE
WIDESPREAD BLOWING AND DRIFTING SNOW. POTENTIALLY SIGNIFICANTLY IN
OPEN AND UNSHELTERED AREAS WITH SUB 1/2 MILE VSBYS LEADING TO WHITE-
OUT, BLIZZARD CONDITIONS.
WINDS WILL START TO SLACKEN MOVING INTO MONDAY EVENING AS THE STORM
HEADS FURTHER EAST AND WEAK HIGH PRESSURE TAKES OVER.
- TEMPS: INFLUX OF COLD, CANADIAN AIR FUNNELS SOUTHWARD ACROSS THE
REGION SUNDAY, POST THE SFC COLD FRONT. 850 MB TEMPS STILL LOOKING
TO DROP FROM AROUND +5 C AT 12Z SUN TO -5 C BY 00Z SUN EVENING. YOUR
SUN HIGH TEMP WILL LIKELY BE AT 12:01 AM.
TEMPERATURES WILL BE FALLING THROUGH THE DAY FOR MOST, AS MUCH AS 10
TO 15 DEGREES FROM NOON TO 6 PM SUN AFTERNOON - FROM NEAR FREEZING
INTO THE UPPER TEENS AND LOWER 20S. STANDING WATER, WET UNTREATED
SURFACES WILL QUICKLY FREEZE - ADDING AN ADDITIONAL TRAVEL HAZARD.
IN ADDITION, THE QUICK FREEZE WILL LIKELY RESULT IN THE EXISTING
SNOW PACK RAPIDLY DEVELOPING A "CRUST". WHY DOES THIS MATTER?
ADDITIONAL SNOWFALL ON TOP OF THIS NOW SLICK, SOMEONE
FRICTIONLESS SFC, WILL BE ABLE TO MOVE READILY. WITH WIND GUSTS
UPWARDS OF 40 MPH, WIDESPREAD BLOWING/DRIFTING COULD/WOULD
RESULT, ALONG WITH SUB 1/2 MILE VISIBILITIES. VOILA - YOU HAVE
NEAR BLIZZARD, WHITE- OUT CONDITIONS. A FAIR AMOUNT OF "IFS"
THERE THOUGH. SNOW "TYPE" CHANGES THROUGH THE DAY/NIGHT,
BECOMING LIGHTER-MORE FLUFFY MOVING INTO THE LATE
EVENING/OVERNIGHT HOURS. HOW MUCH OF THAT FALLS, AND WHERE? SOME
UNCERTAINTIES CONTINUE AND NOT A CLEAR ANSWER TO THAT YET.
> NEXT WEEK: COLDER, OCCASIONAL LIGHT SNOW CHANCES
THE UPPER LEVEL TROUGH ISN'T GOING ANYWHERE FAST AS WE MOVE INTO THE
NEW WEEK. THE GEFS AND EPS KEEP THE UPPER MISSISSIPPI RIVER VALLEY
UNDER ITS INFLUENCE THROUGH AT LEAST FRIDAY. A SPATE OF COLD DAYS
WILL ROUND OUT 2025 AND KICK OFF 2026. HIGHS MOST DAYS WILL BE IN
THE TEENS WITH TUE THE ONLY DAY FLIRTING WITH THE NORMAL. THU
TRENDING THE COLDEST WITH 75% OF THE GEFS SUGGESTING HIGHS NEVER
WARM OUT OF THE SINGLE DIGITS. THE EPS IS A BIT WARMER BUT STILL
HOLDS IT IN THE TEENS.
THE GEFS AND EPS HAVE BEEN STEADY IN SLIDING SHORTWAVE TROUGHS
ACROSS THE REGION TUE AND AGAIN WED. BOTH BRING LIGHT SNOW WITH THE
WED SYSTEM TAKING MORE A DIRECT BEAD ON THE LOCAL AREA AND MIGHT
PRODUCE MORE THAN JUST "LIGHT" SNOW. KEEP AN EYE ON THAT ONE.
> IT'S A WRAP: THANK YOU...
AFTER 34 PLUS YEARS IN THE NATIONAL WEATHER SERVICE, NEARLY 30 OF
WHICH WERE SPENT AT THE LA CROSSE OFFICE, I AM HANGING UP MY
THERMOMETER AND CALLING IT A CAREER.
WHILE I HAVEN'T ALWAYS BEEN RIGHT, YOU ALWAYS GOT THE BEST I COULD
GIVE. THAT DAY. THAT NIGHT. THAT WEEKEND. THAT HOLIDAY. I'VE LEARNED
MUCH, PROBABLY FORGOT MORE, AND HOPEFULLY HELPED YOU THROUGH THE
YEARS PLAN YOUR DAY/WEEK - WHETHER IT BE SUNNY, STORMY, OR SOMETHING
IN BETWEEN.
I AM PROUD OF WHAT I ACCOMPLISHED IN MY CAREER AND LOVE BEING A
"WEATHERMAN". BUT MOSTLY, WHAT MATTERS MOST TO ME, IS I GOT TO BE A
METEOROLOGIST FOR THE NATIONAL WEATHER SERVICE. SERVING YOU, THE
AMERICAN PUBLIC. QUITE A PRIVILEGE. THANK YOU AND ALL THE BEST...
AVIATION /00Z TAFS THROUGH 00Z MONDAY/
ISSUED AT 529 PM CST SAT DEC 27 2025
IFR TO LIFR CONDITIONS CURRENTLY PRESENT ACROSS THE UPPER
MISSISSIPPI VALLEY THIS EVENING. SIMILAR TO THE PAST FEW NIGHTS,
IMPROVEMENT IS NOT EXPECTED IN CIGS WITH VISIBILITIES LIKELY
DROPPING (ESPECIALLY ACROSS WISCONSIN) THROUGH THE EVENING AND
OVERNIGHT HOURS WITH WIDESPREAD DENSE FOG ALREADY BEING
REPORTED ACROSS NE IOWA AND SE MINNESOTA. FOG WILL REMAIN UNTIL
AT LEAST MID MORNING TOMORROW BEFORE RAIN STARTS TO MOVE IN
FROM THE WEST ALONG AN APPROACHING COLD FRONT. RAIN WILL QUICKLY
TRANSITION TO SNOW WITH A FEW HOURS OF WINTRY MIX POSSIBLE BY
LATE MORNING AND EARLY AFTERNOON. SNOW WILL BECOME THE
PREDOMINANT PRECIPITATION TYPE THROUGH THE AFTERNOON WITH
BLOWING SNOW BECOMING MORE LIKELY WEST OF THE RIVER AS WINDS
BEGIN TO PICK UP SIGNIFICANTLY. BY TOMORROW EVENING, WINDS WILL
BE GUSTING OUT OF THE NORTHWEST BETWEEN 30-40 KTS ACROSS SE
MINNESOTA AND NE IOWA (INCLUDING THE RST TERMINAL). GUSTS WON'T
START TO PICK UP UNTIL LATE IN THE PERIOD FOR KLSE AND EAST OF
THE RIVER WITH WINDS PEAKING TOMORROW NIGHT AFTER 00Z.
ARX WATCHES/WARNINGS/ADVISORIES
WI...WINTER WEATHER ADVISORY FROM 3 PM SUNDAY TO NOON CST MONDAY
FOR WIZ053>055-061.
WINTER STORM WARNING FROM NOON SUNDAY TO 9 AM CST MONDAY FOR
WIZ032.
WINTER STORM WARNING FROM 3 PM SUNDAY TO NOON CST MONDAY FOR
WIZ017-029-033-034-041>044.
DENSE FOG ADVISORY UNTIL 9 AM CST SUNDAY FOR WIZ017-029.
MN...DENSE FOG ADVISORY UNTIL NOON CST SUNDAY FOR MNZ079-086>088-
094>096.
WINTER STORM WARNING FROM NOON SUNDAY TO 9 AM CST MONDAY FOR
MNZ079-086>088-094-095.
WINTER STORM WARNING FROM 3 PM SUNDAY TO NOON CST MONDAY FOR
MNZ096.
IA...DENSE FOG ADVISORY UNTIL NOON CST SUNDAY FOR IAZ008>011-018-
019-029-030.
WINTER WEATHER ADVISORY FROM NOON SUNDAY TO 9 AM CST MONDAY
FOR IAZ008-009-018-019.
WINTER WEATHER ADVISORY FROM 3 PM SUNDAY TO NOON CST MONDAY
FOR IAZ010-011-029-030.
DISCUSSION...RIECK
AVIATION...BARENDSE
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