332
FXUS63 KARX 041732
AFDARX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
1232 PM CDT MON MAY 4 2026
KEY MESSAGES
- ELEVATED FIRE WEATHER CONDITIONS ARE EXPECTED TODAY DUE TO
BREEZY AND DRY CONDITIONS.
- SLIGHTLY ABOVE NORMAL TEMPERATURES EXPECTED TODAY CEASE BY
TUESDAY WITH BELOW NORMAL TEMPERATURES RETURNING. FROST
POTENTIAL FOR SOME MONDAY THROUGH FRIDAY NIGHTS.
- PRECIPITATION/MEAGER STORM CHANCES (20-30%) THIS
AFTERNOON/EVENING WITH LOW RAIN CHANCES (30%) RETURNING BY
THURSDAY AFTERNOON. OTHERWISE, GENERALLY DRY CONDITIONS
AREAWIDE.
DISCUSSION
ISSUED AT 436 AM CDT MON MAY 4 2026
THE WIDESPREAD ABOVE NORMAL TEMPERATURES COME TO AN END TODAY AS A
FRONTAL BOUNDARY SAGS SOUTHEAST THROUGH THE FORECAST AREA CAUSING A
15-20 DEGREE SPREAD IN FORECASTED DAYTIME HIGHS. AN EARLIER
PROGRESSION TO THE FRONTAL PASSAGE IN HREF MEMBER RUNS HAS
DECREASED EXTENT AND DEGREE OF LOCAL WARMTH TODAY, CURRENTLY
EXPECTED IN SOUTHERN PERIPHERAL COUNTIES FROM NORTHEAST IOWA
INTO SOUTHWEST WISCONSIN. SOME TEMPORAL DISCONTINUITIES WITHIN
RECENT HRRR RUNS REGARDING EXACT PLACEMENT SUGGESTS SOME
SHIFTING NORTHWEST- SOUTHEAST REMAINS POSSIBLE MOSTLY DEPENDENT
ON COINCIDING DIURNAL HEATING INFLUENCE; I.E., LATER PASSAGE,
WARMER TEMPERATURES BUILD FARTHER NORTHWEST THROUGH THE FORECAST
AREA.
OTHERWISE, LIMITED IMPACTS FROM LIGHT, LOW PRECIPITATION CHANCES
WITH FRONTAL PASSAGE. SIMILAR TO TEMPERATURES, EXACT TIMING OF
FRONTAL PASSAGE REMAINS THE INHERENT DISCREPANCY WITH A 3 - 5 HOUR
WINDOW BETWEEN HREF MEMBERS AND THE NBM HOURLY POPS AT THE CURRENT
FORECAST HOUR. THEREFORE, HAVE PAINTED MORE WIDESPREAD THAN WILL BE
REALIZED 15% TO COVER THE TIMING SPREAD WHILE THE ACTUAL TIMING WILL
BE LIMITED TO 1 HOUR +- 30 MINUTES FOR MUCH OF THE AREA WHEN
SATURATION MANAGES TO SUCCESSFULLY OVERCOME THE ONGOING LOWER LEVEL
DRY AIR OUTSIDE OF SOUTHWEST WISCONSIN INTO NORTHEAST IOWA WHERE
POPS LIKELY LINGER WITHIN THE WARM SECTOR. WHILE ALSO
DEPENDENT UPON FRONTAL BOUNDARY LOCATION, CURRENT FORECAST
CONFIDENCE FOR LOCAL STORM CHANCES, POTENTIALLY STRONG TO SEVERE
UPON INITIATION BEFORE QUICKLY EXITING THE LOCAL FORECAST AREA,
LIMITED TO FAR SOUTHERN PERIPHERAL COUNTIES (CLAYTON COUNTY, IA &
GRANT COUNTY, WI) PRIMARILY.
GIVEN THE EXPECTED LIGHT RAIN AMOUNTS, WITH WARM AND BREEZY
CONDITIONS EXPECTED TODAY, ELEVATED FIRE WEATHER CONDITIONS ARE
EXPECTED AS RH VALUES WILL PROBABLY (50-80% PER 04.00Z REFS) DIP
BELOW 30 PERCENT. ANY RAIN SHOULD SIMPLY DELAY AND MUTE THE RH
FALLS A BIT DUE TO EXPECTED LIGHT AMOUNTS. LIMITING FACTORS FOR
FIRE WEATHER CONDITIONS TODAY LOOK TO BE SKY COVER LIMITING
MIXING AND THE FUELS WHICH, WHILE STILL IN A TRANSITION STATE,
ARE GETTING PRETTY GREEN OUT THERE.
SLIGHTLY COOLER LOW LEVEL TEMPERATURE TRENDS WITHIN LREF MEMBERS
HAVE RESULTED IN SLIGHTLY (1-2 DEGREE) COOLER TEMPERATURES THROUGH
THE WEEK THAN PREVIOUSLY FORECASTED WITH DAYTIME HIGHS IN THE MID
50S FOR MOST TUESDAY THROUGH FRIDAY. MORE IMPACTFUL OVERNIGHT FROST
AND/OR FREEZE POTENTIAL AFFECTS SLIGHTLY MORE OF SOUTHEAST
MINNESOTA LOCALLY INITIALLY MONDAY NIGHT, BECOMING WIDESPREAD
TUESDAY NIGHT THROUGH THURSDAY NIGHT.
AVIATION /18Z TAFS THROUGH 18Z TUESDAY/
ISSUED AT 1232 PM CDT MON MAY 4 2026
A COLD FRONT WILL MOVE SOUTHEAST THROUGH SOUTHERN WISCONSIN AND
EASTERN IOWA THIS AFTERNOON. SCATTERED SHOWERS AND STORMS ARE
EXPECTED TO DEVELOP IN THESE AREAS. A FEW OF THESE STORMS MAY
BECOME STRONG. THIS WILL BE SOUTH AND EAST OF THE TAF SITES.
BOTH OF THEM WILL SEE MID- AND HIGH CLOUDS THROUGH THIS EVENING.
FOR THIS AFTERNOON, NORTHWEST WINDS WILL BE SUSTAINED IN THE
15 TO 20 KNOT RANGE WITH GUSTS OF 20 TO 30 KNOTS. WITH THE LOSS
OF DIURNAL HEATING AND A RELAXING SURFACE PRESSURE GRADIENT,
NORTHWEST WINDS WILL DECREASE LESS THAN 10 KNOTS TONIGHT.
ARX WATCHES/WARNINGS/ADVISORIES
WI...NONE.
MN...NONE.
IA...NONE.
DISCUSSION...FERGUSON/JAR
AVIATION...BOYNE
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