539
FXUS63 KARX 192328
AFDARX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
528 PM CST MON JAN 19 2026
KEY MESSAGES
- EXTENDED COLD WEATHER ADVISORY IN CLARK & TAYLOR COUNTIES OF
CENTRAL WISCONSIN WHERE APPARENT TEMPERATURES REMAIN NEAR AND
BELOW -25F THROUGH TUESDAY MORNING.
- WIDESPREAD DANGEROUS COLD RETURNS THURSDAY WITH -25F TO -40F
WIND CHILLS POSSIBLE THURSDAY NIGHT THROUGH SUNDAY MORNING.
- SNOWFALL TUESDAY NIGHT & WEDNESDAY AFTERNOON/EVENING. HIGHER
ACCUMULATIONS EXPECTED TUESDAY NIGHT WITH A BAND OF 2" TO 4".
LOWER CONFIDENCE FOR 1"+ WEDNESDAY AFTERNOON/EVENING.
DISCUSSION
ISSUED AT 224 PM CST MON JAN 19 2026
TUESDAY SNOWFALL:
AS THE POLAR SYNOPTIC LOW CHURNS OVER HUDSON BAY ON MID LEVEL GOES
WATER VAPOR IMAGERY, OPEN APPENDAGES SWINGING SOUTHEAST PROVIDE
LOCAL PRECIPITATION CHANCES TUESDAY NIGHT AND WEDNESDAY. SURFACE
CYCLOGENESIS ALONG A LOW LEVEL BAROCLINIC BAROCLINIC BOUNDARY WITHIN
A PHASING LOW-MID LEVEL TROUGH ADVECTS THE DEEPENING LOW ACROSS THE
UPPER MISSISSIPPI RIVER OVERNIGHT TUESDAY INTO WEDNESDAY.
INITIAL PRECIPITATION CHANCES INCREASE TUESDAY EVENING ALONG OUR
WEST FROM ISENTROPIC UPGLIDE AND INCREASING MOISTURE WITHIN LOW
LEVEL RETURN FLOW AS THE LOW STARTS TO PHASE UPON REACHING THE
MISSOURI RIVER VALLEY. FURTHER PHASING INTO THE NIGHTTIME HOURS
INCREASES NORTHWEST TO SOUTHEAST ORIENTED LOW LEVEL
FRONTOGENESIS ACROSS THE SOUTHERN HALF OF THE FORECAST AREA.
CURRENT CONFIDENCE IN TIMING AND PHASING OF THE LOW ALLOWS
PWATS TO RECOVER FROM 10TH PERCENTILE (0.1") TO NEAR 75TH
PERCENTILE (0.3") ACCORDING TO HREF MEAN. THE AMPLE MOISTURE
COMBINED WITH ISOTHERMAL HIGH RESOLUTION SOUNDINGS GRAZING THE
DGZ COULD PROVIDE INCREASED HOURLY SNOWFALL RATES. CURRENT
CONFIDENCE KEEPS RATES 0.5" TO 1" PER HOUR AS ISOTHERMAL
SOUNDINGS ARE A COUPLE OF DEGREES WARMER THAN THE DGZ AS THE
WAVE PROGRESSES. THIS KEEPS OVERALL CONFIDENCE FOR 2" TO 4" OF
ACCUMULATIONS FROM NORTHEAST IOWA INTO SOUTHWEST WISCONSIN BUT
AGAIN, SHOULD LOW LEVEL TEMPERATURES COOL A COUPLE OF DEGREES IN
FUTURE HIGH RESOLUTION SOUNDINGS, AMOUNTS WILL REQUIRE
INCREASING.
LIGHTER SNOWFALL WEDNESDAY AFTERNOON-EVENING:
A SHORT REPRIEVE IN SNOWFALL THROUGH WEDNESDAY MORNING CEASES
WEDNESDAY AFTERNOON AS SYNOPTIC POSITIVE VORTICITY ADVECTION
WITHIN AN ADDITIONAL OPEN WAVE PROGRESSES EAST THROUGH THE UPPER
MISSISSIPPI RIVER VALLEY. ACCOMPANYING LOW LEVEL FRONTOGENESIS
POTENTIALLY DRIVING ADDITIONAL 1"+ SNOW ACCUMULATIONS WITHIN A
STRENGTHENING FRONTAL BOUNDARY REQUIRES FURTHER INVESTIGATION IN
COMING FORECASTS AS PREVIOUS AMPLE MOISTURE IS CARVED AWAY.
LREF CONFIDENCE FOR SNOWFALL IS 70-100% FOR THE WESTERN HALF OF
THE FORECAST AREA WEDNESDAY AFTERNOON DECREASES TO 70% IN THE
EPS (19.12Z), 50% IN THE GEPS (19.12Z), AND 0-40% IN THE GEFS
(19.12Z)FOR THE EASTERN HALF OF THE FORECAST AREA WEDNESDAY
NIGHT. WHILE THIS IS AN INCREASE OVER PREVIOUS FORECASTS, THIS
REMAINS THE LOWEST CONFIDENCE PART OF THE FORECAST AS LINGERING
IMPACTS COULD IMPACT THE WEDNESDAY EVENING COMMUTE. DETERMINISTIC
GFS SOUNDINGS SUGGEST RAPID ERADICATION OF ALL/ANY MOISTURE,
SUSTAINING THE DRIEST FORECAST. UNFORTUNATELY THE GLORIOUS NBM
APPEARS TO BE BUYING INTO THE GFS SOLUTION WITH A LOWER POP
FORECAST.
AS THE SYNOPTIC MID LEVEL LOW FINALLY SHIFTS EAST THROUGH THURSDAY,
FLURRY CHANCES WILL PERSIST. CURRENT LREF (18.00Z) CONFIDENCE FOR
0.1" OF SNOW IN 6 HOURS IS 30%-50% OUTSIDE OF THE GEFS (18.00Z) AT
<10%. UNFORTUNATELY, RESTRICTIONS REGARDING INCREASING POPS
AWAY FROM NBM (1%-3%) AT THE LONGER FORECAST HOUR BUT THERE
WILL LIKELY BE SOME LIMITED IMPACTS TO PLAN AROUND.
COLD LATER IN THE WEEK:
CLEARING SKIES HAVE ALLOWED SURFACE TEMPERATURES TO SLIGHTLY
REBOUND A FEW DEGREES ABOVE & BELOW ZERO FOR APPARENT
TEMPERATURES TO WARM ABOVE -25F. CLASSIC COLD SPOTS IN CENTRAL
WISCONSIN ARE HOLDING ON TO THE COLDEST TEMPERATURES LOCALLY,
THEREFORE EXTENDED THE COLD WEATHER ADVISORY THROUGH TUESDAY
MORNING IN THESE SPOTS IN COLLABORATION WITH NEIGHBORING
FORECAST OFFICES.
RETURN FLOW THROUGH TUESDAY ASSOCIATED WITH INCREASING
PRECIPITATION CHANCES KEEPS DANGEROUS COLD AT BAY THROUGH
MIDWEEK. THE COLD RETURNS ON THURSDAY AS THE 850MB -20C
ISOTHERM, PRESENT LOCALLY EARLIER TODAY, ADVECTS SOUTH THROUGH
THE AFTERNOON/EVENING, QUICKER AND EARLIER THAN PREVIOUS LREF
FORECASTS. ECMWF (19.00Z) EXTREME FORECAST INDEX OF -0.8 TO -0.95
FROM SATURDAY THROUGH SUNDAY NIGHT SUGGESTS "VERY UNUSUAL" COLD
IS LIKELY. AN ACCOMPANYING >0 SHIFT OF TAILS COVERS THE
FORECAST AREA, SUGGESTING A FEW MEMBERS SOLUTIONS FOR 99TH
PERCENTILE COLD TEMPERATURES COMPARED TO MODEL CLIMATE FOR THIS
TIME OF YEAR.
THE SLIGHTLY EARLIER SOLUTION IN THE MOST RECENT LREF (19.12Z)
(ALIGNING WITH EPS DPROG/DT) ALSO PROVIDES AN EARLIER EXIT TO
THE COLDEST TEMPERATURES THROUGH SUNDAY. BESIDES 40-50%
PROBABILITIES IN THE MOST RECENT GEFS (19.12Z) AND EPS (19.12Z)
FOR NEGATIVE SURFACE TEMPERATURES LINGERING OVER THE NORTHERN
HALF OF THE FORECAST AREA THROUGH SUNDAY, THE GEPS (19.12Z)
REMAINS THE OVERALL PROBLEM OUTLIER WITH A WIDESPREAD 80-100%
NIGHTLY PROBABILITIES THROUGH DAY 7.
RESULTANT NBM 25TH TO 75TH 2M TEMPERATURE SPREAD IS 10-15
DEGREES FROM THURSDAY AFTERNOON THROUGH DAY 7. WHILE CURRENT
CONFIDENCE WOULD MEAN COLLABORATING THESE DANGEROUSLY IMPACTFUL
TEMPERATURES, FEALTY TO THE NBM KEEPS FORECASTING AT BAY.
REGARDLESS, REMOVING THE GEPS FROM THE LREF, ACCOMPANYING
PROBABILITIES FOR ADVISORY CRITERIA REACHES 100% THURSDAY NIGHT
THROUGH FRIDAY MORNING, 80-100% FRIDAY NIGHT INTO SATURDAY
MORNING, AND 30-60% SATURDAY NIGHT AND SUNDAY MORNING
(EPS/GEFS). PROBABILITIES FOR WARNING CRITERIA (<-35F) ARE
HIGHEST (80-100%) NORTH OF THE IA/MN BORDER FRIDAY MORNING WHILE
DECREASING TO 40-80% NORTH OF INTERSTATE 94 IN THE EPS FOR
SATURDAY MORNING AND 30-40% IN THE GEFS. THEREFORE, HEADLINES
WILL BE REQUIRED COME THURSDAY NIGHT. DIURNAL HEATING
AVAILABILITY FRIDAY WILL BE FUTURE HEADLINE DIFFICULTY AS LREF
TEMPERATURE PROBABILITIES FLUCTUATE.
AVIATION /00Z TAFS THROUGH 00Z WEDNESDAY/
ISSUED AT 528 PM CST MON JAN 19 2026
A SHORTWAVE TROUGH WILL MOVE SOUTHWEST AND SOUTH OF THE AREA
TONIGHT. THIS SYSTEM WILL BRING WITH IT SOME MID- AND HIGH
CLOUDS TO THE TAFS. ANOTHER SYSTEM WILL APPROACH THE AREA ON
TUESDAY AFTERNOON. THIS WILL BRING SOME SNOW TO THE AREA ON
TUESDAY NIGHT.
ARX WATCHES/WARNINGS/ADVISORIES
WI...COLD WEATHER ADVISORY UNTIL 10 AM CST TUESDAY FOR WIZ017-029.
MN...NONE.
IA...NONE.
DISCUSSION...JAR
AVIATION...BOYNE
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