358
FXUS63 KARX 052333
AFDARX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
633 PM CDT TUE MAY 5 2026
KEY MESSAGES
- BELOW NORMAL TEMPERATURES FOR THE REMAINDER OF THE WEEK,
WARMING BACK TO AROUND AVERAGE ON SATURDAY.
- FREEZING TEMPERATURES EXPECTED EARLY WEDNESDAY MORNING BEFORE
8 AM FOR LOCALES ALONG AND NORTH OF THE I-94 CORRIDOR. NEAR
FREEZING TEMPERATURES FOR THE REST OF THE LOCAL AREA.
- ASIDE FROM A 10-20% CHANCE FOR AFTERNOON SHOWERS ON THURSDAY
AND FRIDAY, LOOK FOR DRY CONDITIONS FOR THE REST OF THE WORK
WEEK. NEXT CHANCE OF WIDESPREAD RAIN COMES LATE SATURDAY AND
EARLY SUNDAY.
DISCUSSION
ISSUED AT 630 PM CDT TUE MAY 5 2026
TONIGHT - WEDNESDAY: COOL AND DRY
NORTHWESTERLY SURFACE FLOW IS USHERING IN A MODIFIED ARCTIC
AIRMASS THAT IS MUCH COOLER AND DRIER THAN WHAT WE'VE BEEN
SEEING FOR MUCH OF THIS SPRING SO FAR. FAIR WEATHER CUMULUS AND
SUBSTANTIAL LOW LEVEL MIXING IS ALLOWING TEMPERATURES TO STAY IN
THE UPPER 40S TO LOW 50S WITH DEW POINTS STEADILY DROPPING INTO
THE TEENS. THOUGH THE AIRMASS IS MUCH DRIER, THE COOLER
TEMPERATURES ARE KEEPING THE WORST OF THE FIRE WEATHER CONCERNS
AT BAY WITH MOST LOCATIONS SEEING RHS BOTTOM OUT IN THE 25-35
PERCENT RANGE. THIS COOL AND DRY TREND WILL CONTINUE INTO
TOMORROW AS A ROBUST HIGH PRESSURE SYSTEM DROPS SOUTH INTO THE
PLAINS WITH OUR AREA REMAINING ON ITS FRINGES.
THE MAIN CONCERN FOR THE NEAR TERM IS THE POTENTIAL FOR
FROST/FREEZE CONDITIONS TONIGHT AND THURSDAY MORNING. AS THE
BOUNDARY LAYER DECOUPLES AND THE NIGHTTIME INVERSION SETS UP,
WINDS WILL STEADILY DECREASE INTO THE OVERNIGHT HOURS. THE
DIURNAL CUMULUS FROM EARLIER IN THE DAY WILL ERODE AND ALLOW FOR
MORE CLEARING AS THE NIGHT PROGRESSES. BOTH OF THESE ALONG WITH
THE DRY AIRMASS WILL ALLOW FOR AMPLE RADIATIONAL COOLING ACROSS
MUCH OF THE REGION TONIGHT. AREAS ALONG AND NORTH OF THE I-94
CORRIDOR AND NOTORIOUS COLD AIR DRAINAGE SPOTS WILL LIKELY SEE
LOWS FALL INTO THE MID TO UPPER 20S WITH MOST OTHER LOCATIONS
HOVERING RIGHT AROUND OR JUST ABOVE FREEZING. AS SUCH HAVE
ISSUED A FREEZE WARNING FOR COUNTIES ALONG AND NORTH OF I-94
WITH A FROST ADVISORY ELSEWHERE. FROST AND FREEZE POTENTIAL WILL
NEED TO BE EVALUATED FURTHER FOR THE COMING DAYS AS THE BULK OF
THE POLAR AIRMASS GETS SHUNTED TO THE EAST OF OUR AREA. BOTH
THE 05.00 LREF AND 05.07 NBM HAVE DECREASING PROBABILITIES OF
TEMPERATURES AT OR BELOW FREEZING BY OVER THE FOLLOWING DAYS.
AREAS ALONG AND NORTH OF 94, PRIMARILY IN THE CHIMNEY REGION
HAVE A 50-80% CHANCE OF SUB-FREEZING LOWS THURSDAY MORNING AND
THAT DROPS TO LESS THAN 30% FOR FRIDAY MORNING. ADDITIONAL
HEADLINES MAY BE NEEDED FOR PORTIONS OF THE AREA THESE DAYS.
THURSDAY - FRIDAY: WARMING WITH A LOW CHANCE OF SHOWERS
AS AN UPPER LOW SPINS ACROSS ONTARIO AND THE HUDSON BAY, WEAK LOBES
OF SHORTWAVE ENERGY ARE EXPECTED TO ROUND THE WESTERN FLANK OF THE
TROUGH AND MOVE OVERHEAD BY LATE WEEK. ALONG WITH INCREASED THETA-E
ADVECTION INTO THE REGION, THIS WILL ALLOW FOR SOME DIURNALLY DRIVEN
SHOWERS TO FORM, ESPECIALLY EAST OF THE MISSISSIPPI, WHERE UPPER
FORCING WILL BE A BIT BETTER. THE MAIN LIMITING FACTOR WILL BE THE
LACK OF MOISTURE RETURN AHEAD OF THIS WITH PERSISTENT WEST/NORTHWEST
LOW LEVEL FLOW KEEPING THINGS FAIRLY DRY. 05.00 LREF GRAND ENSEMBLE
(EC, GEFS, GEPS) PROBABILITIES FOR MEASURABLE PRECIPITATION THURSDAY
AFTERNOON PEAK AROUND 40-50 PERCENT WITH 20 PERCENT FOR FRIDAY. WILL
LEAVE THE NBM POPS AS THEY ARE FOR NOW IN THE 15-30 PERCENT
RANGE BOTH DAYS AS THERE IS STILL PLENTY OF SPATIAL UNCERTAINTY
WITH THE CHANCES FOR SHOWERS. TEMPERATURES WILL FINALLY START TO
WARM BY LATE WEEK AS THE DOME OF COLD AIR ALOFT FINALLY
MEANDERS EAST, ALLOWING FOR TEMPERATURES TO CLIMB BACK INTO THE
60S.
THE WEEKEND: WARMER TO START, MORE RAIN CHANCES
AS THE AFOREMENTIONED DOME OF COLD AIR FINALLY EXITS THE REGION, 850
MB THERMAL RIDGING WILL START TO MOVE INTO THE UPPER MIDWEST BY THE
WEEKEND. LOW LEVEL WARM AIR ADVECTION LOOKS MEAGER OVERALL BUT
SHOULD STILL BE ENOUGH TO HELP TEMPERATURES REACH INTO THE UPPER 60S
TO LOWER 70S BY SATURDAY AFTERNOON, ESPECIALLY ACROSS NORTHEAST
IOWA. A COLD FRONT IS THEN EXPECTED TO DROP DOWN INTO THE REGION
LATE SATURDAY INTO SUNDAY, BRINGING THE BEST CHANCES FOR RAIN WITH
ITS PASSAGE. THERE ARE STILL MANY DETAILS THAT WILL NEED TO BE
IRONED OUT AHEAD OF THIS WITH PLENTY OF SYNOPTIC UNCERTAINTY AT THIS
TIME. NOT SURE IF THIS IS GOING TO PROVIDE MUCH RELIEF TO THE DRY
CONDITIONS AS MOISTURE RETURN REMAINS ON THE LOW SIDE AHEAD OF THIS
FRONTAL PASSAGE BUT THIS WILL BE MONITORED GOING FORWARD. POST
FRONTAL TEMPERATURES WILL BE NEAR NORMAL IN THE 60S FOR THE START OF
THE NEXT WORK WEEK.
AVIATION /00Z TAFS THROUGH 00Z THURSDAY/
ISSUED AT 630 PM CDT TUE MAY 5 2026
MAINLY VFR CONDITIONS ARE FORECAST FOR THE TAF PERIOD OUTSIDE
OF A 10-20% CHANCE FOR MVFR CEILINGS AROUND MIDDAY WEDNESDAY
NORTH OF AN EAU TO MFI LINE. DAYTIME CEILINGS ELSEWHERE WILL
OTHERWISE BE AROUND 4-6 KFT THROUGH THE MIDDAY TO AFTERNOON ON
WEDNESDAY. WINDS REMAIN FROM THE NORTHWEST AROUND 5 KTS
OVERNIGHT, INCREASING TO 10-15G15-20KTS FOR THE MIDDAY TO
AFTERNOON ON WEDNESDAY.
ARX WATCHES/WARNINGS/ADVISORIES
WI...FROST ADVISORY FROM 2 AM TO 8 AM CDT WEDNESDAY FOR WIZ032-041-
053>055-061.
FREEZE WARNING FROM 2 AM TO 8 AM CDT WEDNESDAY FOR WIZ017-029-
033-034-042>044.
MN...FROST ADVISORY FROM 2 AM TO 8 AM CDT WEDNESDAY FOR MNZ079-
086>088-094>096.
IA...FROST ADVISORY FROM 2 AM TO 8 AM CDT WEDNESDAY FOR IAZ008>011-
018-019-029-030.
DISCUSSION...BARENDSE
AVIATION...SKOW
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