629  
FXUS63 KMKX 302023  
AFDMKX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI  
323 PM CDT TUE JUN 30 2026  
   
KEY MESSAGES
 
 
- EXTREME HEAT WARNING IN EFFECT FOR ALL OF SOUTHERN WI TONIGHT  
THROUGH WEDNESDAY EVENING. ADDITIONAL HEAT HEADLINES MAY BE  
NEEDED FOR THE SECOND HALF OF THE WEEK, BUT SOME UNCERTAINTY  
REMAINS DUE TO CLOUDS AND RAIN CHANCES.  
 
- THUNDERSTORM CHANCES RETURN THIS EVENING THROUGH THE END OF  
THE WEEK AS THE HOT AND HUMID PATTERN CONTINUES. BEST CHANCES  
ARE TONIGHT (MAINLY NORTH OF A LINE FROM LONE ROCK TO FOND DU  
LAC), THROUGH FRIDAY ON A MORE AREAWIDE BASIS. STRONG TO  
SEVERE STORMS MAY OCCUR AT TIMES.  
 

 
   
SHORT TERM
 
 
ISSUED 255 PM CDT TUE JUN 30 2026  
 
TONIGHT THROUGH WEDNESDAY NIGHT:  
 
HOT AND HUMID CONDITIONS CONTINUE INTO TONIGHT WITH HEAT INDEX  
VALUES REMAINING IN THE 100 TO 105 RANGE. TONIGHT, HEAT WILL  
REMAIN A CONCERN, AS OVERNIGHT LOWS WILL ONLY DROP INTO THE MID  
TO UPPER 70S.  
 
THE RIDGE HELD FAST THROUGH TODAY KEEPING STORM ACTIVITY NORTH  
OF THE AREA, BUT TONIGHT, MODELS DEPICT SOME STORM ACTIVITY OVER  
CENTRAL INCREASING THROUGH THE OVERNIGHT HOURS AS THE  
ENVIRONMENT UNCAPS AND THE LLJ KICKS OFF CONVECTION. STORM  
MOTION VECTORS WOULD CARRY ANY STORMS OVER CENTRAL WI TO THE  
NORTHEAST SPARING MOST OF THE AREA, BUT AREAS NORTH OF A LINE  
FROM LONE ROCK TO FOND DU LAC MAY SEE A GLANCING BLOW FROM  
THUNDERSTORM ACTIVITY. GIVEN THE STEEP MID LEVEL LAPSE RATES,  
LARGE HAIL MAY OCCUR WITH ANY STORMS, AND THERE MAY BE SOME WET  
MICROBURST POTENTIAL GIVE THE HIGH PWATS AND LOW SHEAR. THIS  
ACTIVITY WOULD MOVE THROUGH JUST BEFORE AND JUST AFTER DAWN ON  
WEDNESDAY.  
 
AFTER MORNING THUNDERSTORM ACTIVITY, MORE HOT AND HUMID  
CONDITIONS ARE EXPECTED WITH HIGHS IN THE LOW TO MID 90S, WITH  
HEAT INDICES ABOVE 100.  
 
CMILLER  
 

 
   
LONG TERM
 
 
ISSUED 256 CDT TUE JUN 30 2026  
 
THURSDAY THROUGH TUESDAY:  
 
THE UPPER LEVEL RIDGE BEGINS TO FLATTEN THURSDAY ALLOWING MORE  
THUNDERSTORM ACTIVITY INTO THE AREA. THERE LOOKS TO BE SOME  
POTENTIAL FOR A MORNING ROUND, FOLLOWED BY A LATE AFTERNOON AND  
EVENING ROUND. THE LATTER ROUND MAY FEATURE MORE OF THE SEVERE  
THREAT, GIVEN THE POTENTIAL FOR INSTABILITY TO BUILD THROUGH  
THURSDAY.  
 
BEYOND, THE RIDGE SINKS SOUTHWARD, ALLOWING A MORE FAVORABLE  
BAND OF FLOW ALOFT TO PASS OVER THE AREA INTO THE WEEKEND. DAILY  
THUNDERSTORM CHANCES LOOK POSSIBLE, BUT EACH DAYS CHANCES WILL  
BE HIGHLY DEPENDENT UPON WHERE THE PREVIOUS DAY'S ROUNDS OF  
STORMS FORCE AN OUTFLOW BOUNDARY TO FLOW AND ACT AS A STORM  
TRIGGER. AS SUCH A HIGH AMOUNT OF UNCERTAINTY WILL LINGER INTO  
THE 4TH OF JULY WEEKEND REGARDING STORM TIMING/POSITION.  
 
HOT AND HUMID CONDITIONS WILL LINGER THROUGH FRIDAY. WITH HIGHS  
NEAR OR INTO THE 90S. TEMPS "COOL" THIS WEEKEND WITH HIGHS IN  
THE 80S, BUT DEWPOINTS WILL REMAIN ELEVATED INTO NEXT WEEK,  
PROLONGING THE MUGGINESS.  
 
CMILLER  
 

 
   
AVIATION
 
 
ISSUED 253 PM CDT TUE JUN 30 2026  
 
BREEZY SOUTHWEST WINDS CONTINUE THIS AFTERNOON AMID A MIXTURE OF  
MVFR CIGS AND SCT TO CLR SKYCON IN SOME SPOTS. CUMULUS CLOUDS  
AND WIND WILL LINGER UNTIL SUNSET, WHEN DAYTIME MIXING SUBSIDES.  
 
OVERNIGHT, THUNDERSTORMS ACTIVITY MAY FOR OVER WEST CENTRAL WI,  
ADDING HIGH CIRRUS TO THE SKIES. STORMS ARE MAINLY EXPECTED TO  
STAY NORTH OF A LINE FROM KLNR TO KFLD TONIGHT INTO EARLY  
WEDNESDAY.  
 
STORMS ARE EXPECTED TO MOVE OFF BY LATE WED MORNING AND THEN A  
SIMILAR MIX OF VFR AND MVFR CONDITIONS MAY TAKE HOLD AGAIN  
TOMORROW AFTERNOON.  
 
CMILLER  
 

 
   
MARINE
 
 
ISSUED 245 AM CDT TUE JUN 30 2026  
 
MODEST TO BREEZY SOUTHERLY WINDS WILL PREVAIL INTO THURSDAY THEN  
LIGHTER INTO FRIDAY AS HIGH PRESSURE REMAINS TO THE SOUTHEAST  
OF THE GREAT LAKES, WHILE TROUGHS OF LOW PRESSURE CONTINUE OVER  
CANADA INTO THE NORTHERN GREAT PLAINS. SCATTERED THUNDERSTORMS  
ARE FORECAST ACROSS THE NORTHERN HALF TONIGHT THROUGH WEDNESDAY  
NIGHT, AND ACROSS THE SOUTHERN TWO THIRDS THURSDAY INTO FRIDAY,  
AND ACROSS THE WHOLE LAKE FRIDAY INTO SATURDAY AS A COLD FRONT  
SHIFTS WINDS TO NORTHERLY. PATCHY MARINE FOG WILL BE POSSIBLE AT  
TIMES, PRIMARILY OVER THE NORTHERN HALF OF THE LAKE, AS A WARM  
MOIST AIR MASS MOVES OVER THE LAKE.  
 
CMILLER  
 

 
   
MKX WATCHES/WARNINGS/ADVISORIES
 
 
WI...NONE.  
LM...SMALL CRAFT ADVISORY...LMZ643-LMZ644-LMZ645-LMZ646 UNTIL 10 PM  
TUESDAY.  
 

 
 

 
 
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