632
FXUS63 KARX 311751
AFDARX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
1151 AM CST SAT JAN 31 2026
KEY MESSAGES
- SLIGHTLY WARMER, ALBEIT BELOW NORMAL, TEMPERATURES PERSIST
THROUGH THE FIRST HALF OF THE WEEK. APPARENT TEMPERATURES PEAK
INTO THE 20S FOR SOME TODAY; THE FIRST TIME IN A COUPLE
WEEKS.
- SNOWFALL CHANCES INCREASE OVERNIGHT THROUGH SUNDAY MORNING.
HIGHEST ACCUMULATIONS OF 1" TO 2" EXPECTED SOUTHWEST OF I-94
THROUGH NORTHEAST IOWA.
- MORE SEASONABLE TEMPERATURES RETURN THROUGH MIDWEEK WITH
PRECIPITATION AND SNOWFALL CHANCES INCREASING THURSDAY.
DISCUSSION
ISSUED AT 318 AM CST SAT JAN 31 2026
WARMER, ALBEIT BELOW NORMAL TEMPERATURES TODAY:
WHILE BELOW NORMAL TEMPERATURES CONTINUE TODAY, THE COLDEST
(10TH PERCENTILE IN SPC RAOB CLIMATOLOGY) LOW LEVEL
TEMPERATURES EXITING SOUTH THROUGH THE MISSISSIPPI RIVER VALLEY,
ACCOMPANYING CYCLONIC FLOW ON GOES UPPER LEVEL WATER VAPOR
IMAGERY, WILL PERMIT A RETURN TO MORE SEASONABLE CONDITIONS.
COMBINATION OF 850MB TEMPERATURES RETURNING TO NEAR MEDIAN (SPC
RAOB CLIMATOLOGY) WITH AN AMPLIFIED LOW LEVEL RIDGE TRAVERSING
THE FORECAST AREA PERMITTING INCREASED DIURNAL HEATING WHILE
DECREASING WIND SPEEDS, MEANS APPARENT TEMPERATURES WILL POP
INTO THE 20S FOR THE FIRST TIME IN A COUPLE WEEKS FOR SOME.
UNFORTUNATELY, THE MOSTLY CLEAR SKIES WILL ALSO PERMIT TEMPERATURES
TO DROP POST DIURNAL HEATING. AN INCOMING FRONTAL BOUNDARY TONIGHT
WILL EVENTUALLY INCREASE CLOUD COVER AND WIND SPEEDS AHEAD OF
INCREASING PRECIPITATION CHANCES THROUGH SUNDAY MORNING. WHILE STILL
A FEW DEGREES WARMER, RESULTANT WIND CHILLS TONIGHT EXPECTED TO
REMAIN BELOW 0F.
BELOW NORMAL TEMPERATURES PERSIST INTO THE NEW WEEK:
DIFFERENCES BETWEEN DETERMINISTIC (ECMWF/GFS/CMC) AND
ACCOMPANYING ENSEMBLE (EPS/GEFS/GEPS) MODEL MEMBERS IN STRENGTH
AND SOUTHERN PERIPHERY OF COLDEST POST-FRONTAL LOW LEVEL AIR
DIFFERS PROBABILITIES FOR BELOW -10 WIND CHILLS PERSISTING FOR
/SOME/ PART OF THE FORECAST AREA THROUGH MIDWEEK. REGARDLESS,
WHILE CURRENT NBM FORECAST CALLS FOR ABOVE 0 WIND CHILLS THROUGH
THE START OF THE WEEK, STRONGER POST FRONTAL WINDS WITHIN THE
LOW LEVEL CAA REGIME SUNDAY EVENING THROUGH MONDAY MORNING WILL
NEED TO BE ACCOUNTED FOR IN COMING FORECASTS, LIKELY DECREASING
WIND CHILLS BELOW 0 AREA WIDE AGAIN.
HIGHER CONFIDENCE (50%-80%) FOR THIS PATTERN TO BREAK THROUGH
THE WEEK, BRINGING MORE SEASONABLE TEMPERATURES ACROSS THE
FORECAST AREA FOR THURSDAY.
LIGHT SNOWFALL OVERNIGHT THROUGH SUNDAY:
A RIDGE RUNNING PERTURBATION SEEN ON UPPER LEVEL GOES WATER
VAPOR IMAGERY OVER THE CANADIAN ROCKIES WILL PLUNGE SOUTH-
SOUTHEAST THROUGH THE UPPER MISSISSIPPI RIVER VALLEY SUNDAY AS
THE SYNOPTIC PATTERN SHIFTS EAST. BESIDES A NARROW FILAMENT OF
VERY DRY AIR SEEN IN 31.00Z RAOBS AT ABR, 75TH PERCENTILE (SPC
RAOB CLIMATOLOGY) PWATS OF 0.3"+ ACCOMPANY THE QUICKLY
PROGRESSING WAVE, PROVIDING 24-HOUR HREF LPMM/PMM QPF OF 0.15"
FOR MUCH OF THE FORECAST AREA. COMBINED WITH EXPECTED SLRS OF
15:1, EXPECT 1" TO 2" OF SNOWFALL PRIMARILY ALONG AND WEST OF
THE MISSISSIPPI RIVER VALLEY FROM WESTERN WISCONSIN INTO
SOUTHEAST MINNESOTA.
INITIAL WAVE OF HEAVIER (0.5"-1" HR-1) SNOWFALL EXPECTED
OVERNIGHT INTO EARLY SUNDAY MORNING; SAGGING SOUTHEAST WITH
ENHANCED LOW LEVEL FRONTOGENESIS ALONG THE TIGHT FRONTAL
BOUNDARY. SUBSEQUENT SNOWFALL CONTINUES THROUGH MUCH OF SUNDAY
AS LOW LEVEL CAA PERPETUATES SATURATION CONCURRENT WITH SYNOPTIC
FORCING AND LOBES OF FRONTOGENESIS WITHIN THE AMPLIFYING LOW
LEVEL TROUGH. AMOUNT OF SUBSEQUENT COVERAGE REMAINS IN QUESTION
AS THE WAVE DIGS SOUTH. GIVEN ITS DRY BIAS, THE NBM DROPS POPS
OFF QUICKLY SUNDAY AFTERNOON/EVENING WHILE LONG TERM MODEL
CONSENSUS KEEPS PROBABILITIES INTO SUNDAY NIGHT. THEREFORE, HAVE
INCREASED POPS EAST OF THE MISSISSIPPI RIVER VALLEY IN
COLLABORATION WITH NEIGHBORING FORECAST OFFICES.
PREVIOUS FREEZING DRIZZLE AND SUBSEQUENT ICING SIGNAL SEEN
PRIMARILY IN THE RAP FORECAST MODEL PERSISTS THROUGH THE
OVERNIGHT FORECAST. ASSOCIATED FORECAST SOUNDINGS SUGGEST
RANDOM, TRANSIENT LOSSES OF UPPER LEVEL ICE BETWEEN AND WITHIN
THE PERIPHERY OF SNOWFALL. GIVEN THE LIMITED MEMBERSHIP AND
CONFIDENCE, HAVE KEPT OUT OF FORECAST GRIDS IN COLLABORATION
WITH NEIGHBORING FORECAST OFFICES BUT WILL BE SOMETHING TO
REMAIN COGNIZANT OF.
SUBSEQUENT SNOWFALL THROUGH THE WEEK:
DECREASING SNOWFALL PROBABILITIES FOR TUESDAY IN MOST RECENT
(31.00Z) LONG TERM GLOBAL ENSEMBLES (EPS/GEFS/GEPS) STEM FROM A
DEEPER SOLUTION TO SUNDAY'S TROUGH LINGERING THE COLDER, DRIER
AIRMASS LOCALLY. RESULTANT HIGHER PROBABILITIES HAVE SHUNTED
WELL OFF TO THE SOUTHWEST OF THE FORECAST AREA.
SUBSEQUENT IMPACTS FROM SNOWFALL EXPECTED THURSDAY THROUGH
FRIDAY MORNING; CURRENT FORECAST PROBABILITIES FOR 1" IN 24
HOURS FROM 20% TO 50% IN THE EPS AND 0% TO 30% IN THE GEFS
ALONG AND EAST OF THE MISSISSIPPI RIVER VALLEY.
AVIATION /18Z TAFS THROUGH 18Z SUNDAY/
ISSUED AT 1151 AM CST SAT JAN 31 2026
VFR CONDITIONS FOR THE DAY, AHEAD OF A WEATHER SYSTEM THAT
SHOULD BRING IFR VISIBILITY SNOW TO THE AREA BEGINNING LATER
OVERNIGHT. TIMING IS STILL NOT EXACT, BUT OVERALL FEEL IFR -SN
SHOULD OCCUR +/- 2 HOURS OF THAT CONTAINED IN THE 18Z TAF
ISSUANCES FOR KRST AND KLSE. SOME QUESTIONS REMAIN ON HOW FAST
SATURATION WILL OCCUR WITH DRY AIR IN PLACE AS THE LIFT MOVES
IN.
IFR CIGS WILL LIKELY FOLLOW LATER SUNDAY MORNING AS CONTINUED
SATURATION OCCURS OVER SOUTHEAST MN. LOWEST VISIBILITIES AND
HIGHER SNOW TOTALS OF 1-2 INCHES LOOK MOST FAVORABLE FOR MUCH
OF THE AREA SOUTHWEST OF I-94. LIGHT SNOW (AND PROBABLY IFR
CONDITIONS) WILL PERSIST FOR MUCH OF SUNDAY BEFORE EXISTING EAST
IN THE EVENING.
ARX WATCHES/WARNINGS/ADVISORIES
WI...NONE.
MN...NONE.
IA...NONE.
DISCUSSION...JAR
AVIATION...BAUMGARDT
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