300
FXUS63 KARX 010541
AFDARX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
1241 AM CDT FRI MAY 1 2026
KEY MESSAGES
- BELOW NORMAL TEMPERATURES LINGER ACROSS THE REGION TODAY AND TONIGHT,
WITH HIGHS IN THE 50S AND LOWS IN THE 20S TO 30S. ANOTHER
FROST/FREEZE HEADLINE WILL LIKELY BE NEEDED TONIGHT INTO
SATURDAY MORNING.
- TEMPERATURES TREND WARMER AND TOWARDS NORMAL SATURDAY INTO
EARLY NEXT WEEK.
- PERIODIC CHANCES FOR RAIN CONTINUE INTO EARLY NEXT WEEK.
ISOLATED SHOWERS ARE POSSIBLE THIS AFTERNOON (10-30%) WITH
MORE WIDESPREAD RAIN SUNDAY MORNING AND AGAIN MONDAY.
DISCUSSION
ISSUED AT 1234 AM CDT FRI MAY 1 2026
TODAY - SATURDAY: LINGERING COOL TEMPS THEN WARMING
ANOTHER DAY OF BELOW NORMAL TEMPERATURES IS IN STORE FOR THE UPPER
MISSISSIPPI RIVER VALLEY AS WE SIT IN THE BASE OF A LONGWAVE
TROUGH/LOW CHURNING OVER THE GREAT LAKES. NORTHWEST FLOW CONTINUES
USHERING COOL AIR INTO THE REGION FROM THE NORTH WITH MANY MID TO
UPPER LEVEL IMPULSES FOLLOWING SUIT. THE MAIN WAVES FOR TODAY COME
IN THE FORM OF TWO SUBTLE 700HPA SHORTWAVE TROUGHS THAT SLOWLY SWING
SOUTHEASTWARD THROUGH THE DAY. AS THESE WAVES MOVE THROUGH, LOW
LEVEL LAPSE RATES STEEPEN VIA DIURNAL MIXING WHICH MAY ALLOW DIURNAL
CUMULUS AND POSSIBLY SOME SHOWERS TO DEVELOP (10-20%) AGAIN DURING
THE AFTERNOON HOURS. THE MAIN POINT OF UNCERTAINTY REGARDING SHOWERS
IS HOW DRY AIR DEPICTED IN THE SUBCLOUD LAYER IMPACTS THE
PRECIPITATION. TEND TOWARDS THE MAJORITY OF PRECIPITATION FALLING AS
VIRGA ESPECIALLY WITH THE RECENT HRRR/RAP RUNS COMING IN DRIER
ACROSS OUR AREA, SO HAVE LEANED INTO THE LOWER PROBABILITY SPACE.
THAT SAID, CAN'T RULE OUT SOME ISOLATED SPRINKLES/SHOWERS GIVEN THE
ADEQUATE FORCINGS. THOSE NORTH OF I-94 MAY EVEN SEE SOME SNOWFLAKES
MIX IN WITH SHOWERS THAT ARE ABLE TO DEVELOP EARLIER IN THE
AFTERNOON AS TEMPERATURES HOVER JUST ABOVE FREEZING AND THE WET-BULB
TEMPERATURE SIT AT FREEZING, BUT THIS POTENTIAL DECREASES AS THE
AFTERNOON WEARS ON.
AS WE HEAD INTO TONIGHT, LOW LEVEL RIDGING, CLEAR TO MOSTLY CLEAR
SKIES, AND LIGHT TO CALM WINDS PROVIDE A PRIME SET-UP FOR EFFICIENT
RADIATIONAL COOLING AND TEMPERATURES PLUMMETING INTO THE 20S AND
30S. WITH THESE FACTORS IN PLACE, ANOTHER NIGHT OF FROST/FREEZE
CONDITIONS ARE ANTICIPATED, THE MOST FAVORABLE OUT OF THE LAST FEW
NIGHTS. ANOTHER NIGHT OF FROST ADVISORIES AND FREEZE WARNINGS WILL
LIKELY BE NEEDED.
SOUTHERLY FLOW DEVELOPS ON THE BACKSIDE OF THE RIDGE SATURDAY,
BRINGING WARMER TEMPERATURES NORTHWARD AND PUSHING HIGHS TO AROUND
60 DEGREES, NEAR NORMAL FOR THIS TIME OF YEAR.
SUNDAY - EARLY NEXT WEEK: WARMER WITH PERIODIC RAIN CHANCES
WARMER TEMPERATURES LINGER THROUGH THE WEEKEND AS LOW LEVEL
SOUTHERLY FLOW REMAINS THE DOMINANT INFLUENCE OVER OUR AREA. MUCH
HIGHER AGREEMENT IN TEMPERATURES THIS WEEKEND IS NOTED AMONGST THE
NWP/AIWP GUIDANCE AS COMPARED TO YESTERDAY, WHICH HAVE BROUGHT THE
25TH-75TH PERCENTILE SPREAD FROM 10-15 DEGREES TO AROUND 5 DEGREES.
THERE ARE STILL SOME COOLER OUTLIERS IN THESE SOLUTIONS, BUT THE
OVERALL CONSENSUS NOW CENTERS ON TEMPERATURES TOPPING OUT IN
THE 60S TO AROUND 70 THROUGH MONDAY.
850HPA WARM AIR ADVECTION RAMPS UP INTO SUNDAY MORNING ON THE
BACKSIDE OF THE LOW LEVEL RIDGE ALONG WITH A SIGNAL FOR SOME WEAK
MOISTURE TRANSPORT NUDGING INTO THE AREA. AT THE SAME TIME, GLOBAL
DETERMINISTIC MODELS HIGHLIGHT A 700HPA SHORTWAVE DIVING SOUTHWARD
ATOP THE LOW LEVEL FORCINGS WITHIN THE MEAN NORTHWEST FLOW. COMBINED
WITH A SATURATING COLUMN DEPICTED IN GFS SOUNDINGS, CONDITIONS
APPEAR FAVORABLE FOR A ROUND OF RAIN SUNDAY MORNING. THE 30.12Z LREF
SUGGESTS 30-40% PROBABILITIES FOR MEASURABLE RAINFALL DURING THIS
PERIOD WHEREAS THE 30.19Z NBM ONLY HAS 10-20%, LIKELY OWING TO
ITS LOW QPF BIAS.
CONFIDENCE IN TEMPERATURES DECREASES AGAIN AFTER MONDAY. A HIGHER
AMPLITUDE 700-500HPA TROUGH LOOKS TO SWING ACROSS THE NORTHERN
UNITED STATES, DRAGGING A SURFACE COLD FRONT THROUGH THE UPPER
MIDWEST DURING THE DAY MONDAY. SOME VARIATION REGARDING LOCATION AND
TIMING IS NOTED BETWEEN THE MEMBERS OF THE 30.18Z GEFS/EPS AND THEIR
AI COUNTERPARTS, LEADING TO TEMPERATURE SPREADS ON THE ORDER OF 15
TO 20 DEGREES WHICH ARE ALSO NOTED IN THE 30.19Z NBM. DESPITE THE
KINKS TO WORK OUT REGARDING LOCATION AND TIMING, MOST ENSEMBLE
MEMBERS DEPICT THESE FEATURES SHIFTING THROUGH THE AREA IN SOME
CAPACITY. THE 30.12Z LREF TENDS TOWARDS BROADBRUSHED 30-60%
PROBABILITIES WHILE THE 30.19Z NBM DEPICTS A 20-40% CHANCE FOR
MEASURABLE RAINFALL. BOTH ENSEMBLES HIGHLIGHT CENTRAL WISCONSIN
AS THE MOST FAVORABLE LOCATION FOR PRECIPITATION AT THIS POINT.
TEMPERATURES THEN TREND COOLER AGAIN INTO THE MIDDLE OF NEXT
WEEK IN THE WAKE OF THE COLD FRONT.
AVIATION /06Z TAFS THROUGH 06Z SATURDAY/
ISSUED AT 1234 AM CDT FRI MAY 1 2026
VFR CONDITIONS WILL PREVAIL OVER THE NEXT 24 HOURS WITH
OCCASIONAL BOUTS OF CLOUDINESS IN THE 5-10 KFT LAYER. WINDS WILL
TEND TO BE OUT OF THE NORTHWEST DURING THE DAY AND VARIABLE AT
NIGHT.
ARX WATCHES/WARNINGS/ADVISORIES
WI...FROST ADVISORY UNTIL 8 AM CDT THIS MORNING FOR WIZ032-041-054-
061.
FREEZE WARNING UNTIL 8 AM CDT THIS MORNING FOR WIZ017-029-033-
034-042>044-053-055.
MN...FROST ADVISORY UNTIL 8 AM CDT THIS MORNING FOR MNZ079-088-096.
IA...FROST ADVISORY UNTIL 8 AM CDT THIS MORNING FOR IAZ011.
DISCUSSION...FALKINHAM
AVIATION...FERGUSON
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