422
FXUS63 KARX 300510
AFDARX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
1210 AM CDT THU APR 30 2026
KEY MESSAGES
- COOL WEATHER CONTINUES THROUGH FRIDAY WITH HIGHS IN THE 50S
AND LOWS IN THE 30S, LEADING TO PERIODS OF FROST/FREEZE
CONCERN DURING THE OVERNIGHTS. TEMPERATURES WARM TOWARDS
NORMAL THIS WEEKEND AND INTO NEXT WEEK.
- ISOLATED TO SCATTERED SHOWERS ARE POSSIBLE THIS AFTERNOON AND
AGAIN FRIDAY AFTERNOON (10-30%), BUT OVERALL TIMING AND
LOCATION PREDICTABILITY IS LOW.
DISCUSSION
ISSUED AT 1150 PM CDT WED APR 29 2026
COOL TEMPERATURES THEN WARMING
COOL TEMPERATURES LINGER TODAY AND FRIDAY AS AN UPPER LEVEL LOW
CHURNS OVER THE GREAT LAKES REGION. CONFIDENCE REMAINS HIGH IN THESE
TEMPERATURES AS VERY LITTLE SPREAD IN THE 25TH-75TH PERCENTILES,
ON THE ORDER OF 5 DEGREES OR LESS, IS NOTED WITHIN THE MAJORITY
OF THE ENSEMBLE SUITE. DURING THE OVERNIGHT HOURS, THE COLD AIR
STAGNATES UNDER CLEAR TO MOSTLY CLEAR SKIES WITH NEARLY CALM
SURFACE WINDS. THIS SET UP FAVORS FROST/FREEZE CONDITIONS, WHICH
ARE EXPECTED THROUGH SATURDAY MORNING WITH THE CURRENT
FROST/FREEZE HEADLINES POSSIBLY NEEDING TO BE EXPANDED INTO
OTHER COUNTIES FOR THE COMING NIGHTS.
AS WE HEAD INTO THE WEEKEND, TEMPERATURES TREND WARMER AS THE UPPER
LOW SHIFTS EASTWARD, ALLOWING WARMER AIR TO ADVECT INTO THE REGION.
HIGH TEMPERATURES ON SATURDAY REACH INTO THE 60S, AGAIN WITH
LITTLE VARIABILITY IN THE 25TH-75TH PERCENTILES. A BIT MORE
UNCERTAINTY IN EXACT TEMPERATURES COMES INTO PLAY AS WE HEAD
INTO SUNDAY AND EARLY NEXT WEEK. LOOKING AT THE 30.00Z
AIFS ENS/AIGEFS, THE 25TH-75TH TEMPERATURE SPREAD BEGINS TO
INCREASE BEYOND SATURDAY, UPWARDS OF 10-15 DEGREES. THE
IMPORTANT THING TO NOTE IS THAT WHILE THE EXACT TEMPERATURE IS
UNCERTAIN, THE OVERALL WARMING TREND IS STILL DEPICTED DESPITE
THE VARIATION.
SHOWERS THIS AFTERNOON AND FRIDAY
WITH THE BOWLING BALL OF A LOW SITTING ATOP THE GREAT LAKES REGION
THROUGH FRIDAY, SENDING SHORTWAVE TROUGH AFTER SHORTWAVE TROUGH INTO
THE UPPER MISSISSIPPI RIVER VALLEY WITHIN THE NORTHWEST FLOW AND
COLD AIR ADVECTION REGIME, ISOLATED TO SCATTERED SHOWER DEVELOPMENT
APPEARS REASONABLE TO EXPECT BOTH THIS AFTERNOON AND FRIDAY
AFTERNOON. THE PRIMARY 500HPA SHORTWAVE TROUGH THIS AFTERNOON SHIFTS
SOUTHEASTWARD THROUGH THE MORNING HOURS, SPARKING SOME WEAK SURFACE
CYCLOGENESIS OVER EASTERN IOWA AND NORTHWESTERN ILLINOIS THIS
AFTERNOON THAT EVENTUALLY LIFTS SLIGHTLY NORTHWARD INTO
WISCONSIN. FORCING ASSOCIATED WITH THESE FEATURES COMBINED WITH
0-3KM LAPSE RATES STEEPENING TO 7-8C/KM PER THE 30.03Z RAP
SHOULD PROVIDE ENOUGH UPWARD MOTION FOR SOME ISOLATED SHOWERS
DURING THE AFTERNOON, PRIMARILY ACROSS WISCONSIN WHERE THE
FORCING WILL BE MAXIMIZED. A SIMILAR SET-UP OCCURS FOR FRIDAY,
ALBEIT WITHOUT THE CYCLOGENESIS, AS ANOTHER SHORTWAVE PIVOTS
THROUGH THE UPPER MISSISSIPPI RIVER VALLEY WITH COVERAGE
EXPECTED TO BE A BIT MORE EXPANSIVE AS COMPARED TO TODAY. THOSE
FURTHER NORTH, ESPECIALLY NORTH OF I-94, MAY EVEN SEE SOME
SNOWFLAKES MIX IN WITH THE RAIN DURING THE AFTERNOONS. RAP/HRRR
SOUNDINGS SHOW THE MIXED LAYER REACHING INTO THE DGZ WHILE
SURFACE TEMPERATURES REMAIN NEAR FREEZING WITH THE POSSIBILITY
TO WET-BULB BELOW FREEZING. THE MAIN LIMITING FACTOR TO
PRECIPITATION BOTH DAYS IS LOW LEVEL SATURATION. THESE SAME
MODEL SOUNDINGS DEPICT SOME DRY AIR BELOW 5KFT WHICH MAY PROVE
CHALLENGING FOR HYDROMETEORS TO FALL THROUGH, DEPENDENT ON HOW
STRONG THE FORCING ASSOCIATED WITH THE SHOWERS ULTIMATELY ENDS
UP BEING.
AVIATION /06Z TAFS THROUGH 06Z FRIDAY/
ISSUED AT 1210 AM CDT THU APR 30 2026
VFR CONDITIONS ARE EXPECTED THROUGHOUT THE TAF PERIOD WITH SCT TO
BKN CLOUDS BETWEEN 5KFT AND 10KFT. WINDS WILL REMAIN FROM THE
NORTH/NORTHWEST TODAY BUT INCREASE DURING THE LATE MORNING TO AROUND
8-12 KTS. CANNOT RULE OUT A PASSING SHOWER (10-15% CHANCE) AT KLSE
SITE DURING THE AFTERNOON HOURS. HOWEVER GIVEN THE LOW PROBABILITY
AND UNLIKELIHOOD THIS WOULD RESULT IN CATEGORY REDUCTIONS, HAVE
OPTED NOT TO INCLUDE A PROB30 AT THIS TIME.
ARX WATCHES/WARNINGS/ADVISORIES
WI...FROST ADVISORY UNTIL 8 AM CDT THIS MORNING FOR WIZ032-033-041-
053>055.
FREEZE WARNING UNTIL 8 AM CDT THIS MORNING FOR WIZ017-029-034-
042>044.
MN...FROST ADVISORY UNTIL 8 AM CDT THIS MORNING FOR MNZ079.
IA...NONE.
DISCUSSION...FALKINHAM
AVIATION...NAYLOR
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