828  
FXUS63 KMKX 161506 AAA  
AFDMKX  
 
AREA FORECAST DISCUSSION...UPDATED  
NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI  
1006 AM CDT TUE JUN 16 2026  
   
KEY MESSAGES  
 
- SCATTERED SHOWERS AND THUNDERSTORMS (45-65 PERCENT CHANCE)  
WILL DEVELOP ACROSS THE AREA FROM LATE THROUGH MORNING THROUGH  
THIS AFTERNOON. SMALL HAIL AND WIND GUSTS TO 45MPH ARE  
EXPECTED WITH THE THUNDERSTORMS.  
 
- WIDESPREAD SHOWERS (80-90 PERCENT CHANCE) AND SCATTERED  
THUNDERSTORMS WEDNESDAY AND WEDNESDAY NIGHT. HEAVY RAIN AND A  
CONDITIONAL THREAT FOR SEVERE THUNDERSTORMS IS FORECAST.  
 
- WINDS AND WAVES MAY APPROACH SMALL CRAFT ADVISORY CRITERIA  
WEDNESDAY AFTERNOON INTO THURSDAY.  
 
- NEXT NOTEWORTHY CHANCE FOR THUNDERSTORMS IS SUNDAY.  
 
 
   
UPDATE  
 
ISSUED 1006 AM CDT TUE JUN 16 2026  
 
FIRST ELONGATED VORT LOBE HAS SWUNG THROUGH THE REGION,  
DELIVERING A BROKEN LINE OF SHOWERS, AN OCCASIONAL RUMBLE OF  
THUNDER AND LOCALIZED WIND GUSTS IN THE 35MPH TO 45MPH RANGE.  
 
FOR THE REST OF THIS MORNING, A NARROW BAND OF SUBSIDENCE WILL  
KEEP US DRY. THIS WILL BE SHORT LIVED AS THE MAIN AREA OF DEEP  
VORTICITY IS STEADILY MOVING SOUTHEAST INTO THE REGION. WE WILL  
SEE AN UPTICK IN STRATOCUMULUS DEVELOPMENT OVER THE NEXT COUPLE  
OF HOURS, WITH SHOWERS POPPING OVER SOUTHWESTERN PORTIONS OF THE  
STATE PRIOR TO NOON.  
 
SCATTERED SHOWERS AND STORMS WILL DEVELOP IN THE DEEP CYCLONIC  
FLOW, MOVING TO THE EAST AND NORTHEAST. THE BEST COVERAGE LOOKS  
TO BE NORTH OF I-94, WITH LESSENING COVERAGE SOUTH OF I-94.  
SMALL HAIL AND WIND GUSTS TO 45MPH MAY OCCUR WITH STRONGER  
CELLS. THE MAJORITY OF THE ACTIVITY SHOULD SHIFT TO THE EAST BY  
MID AFTERNOON, LINGERING TOWARD FOND DU LAC AND SHEBOYGAN AREAS  
INTO EARLY THIS EVENING.  
 
GAGAN  
 
 
   
SHORT TERM  
 
ISSUED 100 AM CDT TUE JUN 16 2026  
 
TODAY THROUGH WEDNESDAY NIGHT:  
 
THROUGH THE PREDAWN HOURS TODAY, A COMPACT SHORTWAVE IS EXPECTED  
TO TRACK SOUTHEAST FROM MN INTO NORTHWEST WI, INDUCING A NARROW  
LLJ OVER EASTERN IA AND SOUTHERN WI. THE ASSOCIATED WAA MAY  
DEVELOP SOME WIDELY SCATTERED RAINSHOWERS (OR EVEN WEAK  
THUNDERSTORMS) IN THE REGION BETWEEN ROUGHLY 3 AM AND 9 AM THIS  
MORNING. A LULL IN THE SHOWER ACTIVITY WOULD THEN BE LIKELY  
LATE THIS MORNING AS THIS ACTIVITY PUSHES EAST OVER LAKE  
MICHIGAN.  
 
THE SHORTWAVE TROUGH CLOSES OFF INTO A COMPACT UPPER LOW OVER  
CENTRAL PORTIONS OF WI THROUGHOUT THE DAY TODAY, SLOWLY TRACKING  
EAST. THE RELATIVELY COOL AIR ALOFT, PREEXISTING MODEST MID-LEVEL  
LAPSE RATES, AND SHARPENING LOW-LEVEL LAPSE RATES (THROUGH THE  
COURSE OF DAYTIME HEATING) SHOULD ALLOW THIS FEATURE TO PRODUCE A  
SECOND ROUND OF SHOWERS AND THUNDERSTORMS THIS AFTERNOON  
(NOON-7PM), THIS TIME WITH GREATER COVERAGE. THE RELATIVELY LOW  
FREEZING LEVELS (BENEATH 8,000 FT AT TIMES) SHOULD ALLOW ANY  
THUNDERSTORM CELLS TO PRODUCE SMALL HAIL. DRY WEATHER RETURNS  
THIS EVENING.  
 
AS ANOTHER 500MB TROUGH TRACKS SOUTHEASTWARD ACROSS THE DAKOTAS  
TONIGHT, DIFFLUENT FLOW OVERSPREADS IOWA AND AN MCS EVOLVES. 00Z  
MODEL GUIDANCE DEPICTS THIS MCS TRACKING EASTWARD INTO SOUTHERN  
WI AND MUCH OF IL, ARRIVING BETWEEN 5-9 AM WEDNESDAY MORNING.  
WITH HREF MEAN MUCAPE UNDER 1,000 JOULES IN OUR REGION AND  
SUBSTANTIALLY HIGHER INTO IA/IL, IT WOULD APPEAR THAT THE  
MAJORITY OF THE STRONGER / SEVERE STORMS WILL DIVE SOUTH OF OUR  
REGION, LEAVING SUB-SEVERE STORMS (STILL PLENTY CAPABLE OF  
LIGHTNING AND POSSIBLY BRIEF HEAVY RAINFALL) TO OVERSPREAD OUR  
REGION WEDNESDAY MORNING.  
 
DEEP SURFACE LOW PRESSURE BEHIND THE MCS WILL THEN ATTEMPT TO  
DRAW THE EFFECTIVE WARM FRONT (AND INSTABILITY PLUME) NORTHWARD  
INTO FAR SOUTHERN WI WEDNESDAY AFTERNOON. THE 00Z HREF'S BEST  
GUESS IS THAT THE WARM FRONT WILL SETUP JUST SOUTH OF THE WI/IL  
BORDER AND SHIELD US FROM SURFACE BASED CONVECTION (AND THUS  
REDUCE SEVERE WX POTENTIAL), BUT AS STATED DURING THE PRIOR  
FORECAST ITERATION, A SMALL SHIFT IN THE MCS OR LOW PRESSURE  
SYSTEM TRACK COULD STILL BRING THE WARM FRONT AS FAR NORTH AS  
SOUTHERN WI, YIELDING AN ALL-HAZARDS SEVERE THREAT SOUTH OF THE  
I-94 CORRIDOR. STAY TUNED TO THIS FORECAST, AS DETAILS CAN AND  
WILL CHANGE.  
 
SHEPPARD  
 
 
   
LONG TERM  
 
ISSUED 100 AM CDT TUE JUN 16 2026  
 
THURSDAY THROUGH MONDAY:  
 
PREDOMINANTLY DRY WEATHER EXPECTED IN THE COOL SECTOR OF THE  
DEPARTING LOW PRESSURE ON THURSDAY. SOME LINGERING 500MB VORTICITY  
ON THE NORTH EDGE OF THE JET, SOME COOL AIR ALOFT, AND STEEPENING  
LOW-LEVEL LAPSE RATES THROUGH THE COURSE OF DIURNAL HEATING (BELOW  
THE SUBSIDENCE INVERSION) ALLOWS MODELS TO YIELD SOME LOW CHANCES  
OF CELLULAR RAIN SHOWERS THURSDAY (~10-15% CHANCE). A SIMILAR  
STORY FOR FRIDAY, NOT ENOUGH JET DYNAMICS TO SUPPORT MUCH ELSE.  
ENSEMBLE PLOTS FOR HIGH TEMPS SUGGEST A DAYTIME HIGH AROUND 70 /  
LOW 70S FOR THURSDAY, WITH ONLY A VERY SLIGHT OVERALL WARMING  
TREND THIS WEEKEND INTO EARLY NEXT WEEK (ENSEMBLE MEAN HIGH  
TEMPS CENTERED IN THE MID 70S, WITH GROWING DISPERSION).  
 
FOR SATURDAY, THE LONGWAVE TROUGH AXIS CENTERED OVER OUR REGION  
BEGINS TO EXIT EAST (HENCE THE SLIGHT WARMING TREND). WARM/MOIST  
RETURN FLOW OVER THE GREAT PLAINS SETS UP A NW TO SE ORIENTED  
BAROCLINIC ZONE FROM SOUTHERN MN INTO EASTERN IA / NORTHWEST IL  
(AND PERHAPS SOUTHERN WI), WHICH LEAVES THE POTENTIAL FOR A  
RIDGE-RIDING SHORTWAVE TO KICK-OFF AN MCS FRIDAY NIGHT AND TRACK  
IT ALONG THAT GRADIENT TOWARDS OUR REGION SATURDAY MORNING. THE  
MODELS (FOR NOW) SUGGEST THAT THE GRADIENT AND MCS (AS SEEN IN QPF  
OUTPUT) WILL SETUP SOUTHWEST OF US, THOUGH WE HAVE SOME 20-30%  
PRECIP CHANCES ACROSS OUR CWA JUST IN CASE.  
 
OUR NEXT NOTEWORTHY CHANCE FOR THUNDERSTORMS ARRIVES SUNDAY, WITH  
PLENTY OF UNCERTAINTY AS TO HOW THINGS WILL SHAKE OUT. MULTIPLE  
ECMWF ENSEMBLE MEMBERS TRACK AN ORGANIZED LOW PRESSURE SYSTEM  
NORTHEAST FROM THE CENTRAL PLAINS TOWARDS SOUTHERN WI (A SETUP  
WHICH WOULD LEAVE ORGANIZED THUNDERSTORM CHANCES ON THE TABLE),  
WHEREAS SEVERAL GEFS MEMBERS TRACK THE LOW THROUGH ILLINOIS,  
LEAVING US WITH NO SOUTHERLY RETURN FLOW. A LARGE SUBSET OF  
MEMBERS FROM EACH MODELING SYSTEM STALLS THE LOW OVER THE CENTRAL  
PLAINS, LEAVING THE BAROCLINIC ZONE NORTHEAST OF IT AND ANY  
CORRESPONDING SATELLITE LOW PRESSURE TO ATTEMPT A NORTHWARD PUSH  
OF MOISTURE / QPF INTO OUR REGION. ALL THIS TO SAY THE  
PREDICTABILITY IS VERY LOW, BUT THERE ARE CHANCES FOR SHOWERS  
AND THUNDERSTORMS SUNDAY.  
 
SHEPPARD  
 
 
   
AVIATION  
 
ISSUED 608 AM CDT TUE JUN 16 2026  
 
SCATTERED SHOWERS ACROSS THE EAST EARLY THIS MORNING WILL BE  
FOLLOWED BY A BRIEF BREAK IN CLOUDS AND PRECIP AHEAD OF AN  
APPROACHING TROUGH. SHOWERS WILL MOVE BACK IN FROM THE NORTHWEST  
MID TO LATE MORNING ALONG WITH MOSTLY CLOUDY SKIES. CEILINGS MAY  
BRIEFLY DROP TO MVFR AS THE TROUGH ARRIVES, MAINLY NORTHWEST OF  
MADISON. SCATTERED SHOWERS WILL THEN PROGRESS ACROSS THE  
FORECAST AREA LATE MORNING INTO THE AFTERNOON, WITH SOME THUNDER  
AND SMALL HAIL ALSO POSSIBLE BY AFTERNOON.  
 
DRY WEATHER THIS EVENING INTO AT LEAST EARLY TONIGHT WILL GIVE  
WAY TO INCREASING CHANCES FOR SHOWERS LATE TONIGHT INTO  
WEDNESDAY AS THE NEXT TROUGH APPROACHES. MORE WIDESPREAD PRECIP  
AND LOWER CLOUDS ARE EXPECTED WITH THE SYSTEM TOMORROW.  
 
DDV  
 
 
   
MARINE  
 
ISSUED 100 AM CDT TUE JUN 16 2026  
 
SOUTHWESTERLY WINDS SHIFT SOUTHERLY EARLY THIS MORNING AS A LOW  
PRESSURE SYSTEM DEEPENS OVER NORTHERN LAKE MICHIGAN (29.5  
INCHES). WINDS BECOME RELATIVELY LIGHT AND VARIABLE UNDERNEATH  
IT (NORTHERN HALF OF THE LAKE) LATER THIS AFTERNOON, WITH WINDS  
VEERING WEST OVER THE SOUTHERN HALF. SHOWERS AND THUNDERSTORMS  
WILL BE POSSIBLE ACROSS THE LAKE THROUGH THE DAYTIME HOURS  
TODAY, A COUPLE OF STRONGER CELLS THIS AFTERNOON COULD PRODUCE  
SMALL HAIL.  
 
A WEAK SURFACE RIDGE CROSSES THE LAKE TONIGHT, WITH WINDS  
SUBSIDING AND BACKING SOUTHWEST. A MUCH MORE ORGANIZED LOW  
PRESSURE SYSTEM (29.2 INCHES) WILL THEN TRACK EASTWARD FROM  
AROUND SOUTH DAKOTA, CROSSING LAKE MICHIGAN WEDNESDAY EVENING.  
AHEAD OF IT'S ARRIVAL, WE EXPECT GUSTY SOUTHEAST WINDS WEDNESDAY  
MORNING AND AFTERNOON (PARTICULARLY OVER THE SOUTHERN HALF OF  
THE LAKE) WITH INCREASING CHANCES FOR THUNDERSTORMS, SOME OF  
WHICH COULD BE STRONG (PARTICULARLY OVER FAR SOUTHERN PORTIONS  
OF THE LAKE). BREEZY WEST TO NORTHWEST WINDS ARE EXPECTED  
WEDNESDAY NIGHT INTO THURSDAY AS THE LOW EXITS EAST. THIS SAME  
BREEZE THEN CONTINUES INTO FRIDAY (ALBEIT WEAKER) AS WEAK HIGH  
PRESSURE BUILDS INTO THE REGION FROM THE WEST.  
 
SHEPPARD  
 
 
   
MKX WATCHES/WARNINGS/ADVISORIES  
 
WI...NONE.  
LM...NONE.  
 
 
 
 
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