869  
FXUS63 KMKX 240009  
AFDMKX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI  
709 PM CDT SUN AUG 23 2026  
   
KEY MESSAGES  
 
- CRISP, FALL-LIKE CONDITIONS TONIGHT. SOME FOG IS POSSIBLE  
AFTER MIDNIGHT.  
 
- COMFORTABLE & PLEASANT AFTERNOON WEATHER CONDITIONS TODAY  
THROUGH TUESDAY & THURSDAY-FRIDAY.  
 
- WINDOWS FOR SHOWERS & THUNDERSTORMS TUESDAY NIGHT THROUGH  
WEDNESDAY & NEXT WEEKEND.  
 
 
   
UPDATE  
 
ISSUED 709 PM CDT SUN AUG 23 2026  
 
NO MAJOR CHANGES TO THE FORECAST THIS EVENING WITH HIGH PRESSURE  
IN PLACE AND THE FAIR WEATHER CUMULUS SLOW DIMINISHING NOW THAT  
THE SUN IS SETTING. THE CLEAR SKIES TONIGHT, LIGHT WINDS AND  
FALLING TEMPERATURES WILL LEAD TO SOME FOG DEVELOPMENT TONIGHT.  
THE BEST POTENTIAL WILL BE IN LOW LYING AREAS AND RIVER VALLEYS.  
WITH DEWPOINTS ALSO EXPECTED TO FALL A COUPLE DEGREES THERE IS  
A BIT OF UNCERTAINTY IN HOW WIDESPREAD FOG DEVELOPMENT WILL BE.  
OTHERWISE WITH OVERNIGHT LOWS EXPECTED TO FALL INTO THE UPPER  
40S TO MID 50S (WARMER NEAR LAKE MICHIGAN), IT WILL BE A COOL  
AND CRISP NIGHT.  
 
PATTERSON  
 
 
   
SHORT TERM  
 
ISSUED 1200 PM CDT SUN AUG 23 2026  
 
THIS AFTERNOON THROUGH MONDAY NIGHT:  
 
SYNOPSIS/MESOANALYSIS: SOUTHERN WISCONSIN IS CENTERED BETWEEN LOW  
PRESSURE ALONG THE ONTARIO-QUEBEC BORDER & HIGH PRESSURE ALONG THE  
MINNESOTA-IOWA BORDER LATE THIS MORNING, RESULTING IN BREEZY  
NORTHWEST SURFACE WINDS. WITH THE CENTER OF THE HIGH & AFFILIATED  
LOW LEVEL SUBSIDENCE WELL WEST OF THE AREA, SURFACE HEATING IS  
ALLOWING FOR FAIR WEATHER CUMULUS DEVELOPMENT, WITH CUMULUS COVERAGE  
EXPECTED TO INCREASE FURTHER MOVING DEEPER INTO THE AFTERNOON.  
THE AFOREMENTIONED SURFACE HIGH WILL NUDGE INTO SOUTHERN  
WISCONSIN TONIGHT, LEADING TO CLEAR SKIES AND LIGHT SURFACE  
WINDS. THE CLEAR SKIES & LIGHT WINDS WILL ALLOW FOR EFFICIENT  
RADIATIONAL COOLING & FALL-LIKE LOW TEMPERATURES IN THE LOW 50S.  
SOME SPOTS COULD DIP INTO THE UPPER 40S. AREAS OF FOG  
DEVELOPMENT ARE POSSIBLE AFTER MIDNIGHT, PARTICULARLY IN LOW-  
LYING LOCATIONS. FOG WILL QUICKLY DISSIPATE AFTER SUNRISE  
MONDAY, GIVING WAY TO MOSTLY SUNNY SKIES AND PLEASANT WEATHER  
CONDITIONS MONDAY AFTERNOON. HIGH PRESSURE WILL BEGIN TO SHIFT  
EAST OF THE REGION MONDAY NIGHT, ALLOWING SOUTH-SOUTHWEST WINDS  
TO RE-ESTABLISH ACROSS THE AREA.  
 
TONIGHT: WILL BE MONITORING FOR POTENTIAL FOG DEVELOPMENT NEAR/AFTER  
MIDNIGHT AS THE BOUNDARY LAYER ATTEMPTS TO DECOUPLE IN THE PRESENCE  
OF CLEAR SKIES AND LIGHT SURFACE WINDS. FORECAST SOUNDINGS SHOW  
EXTREMELY SHALLOW NEAR-SURFACE MOIST LAYERS SUSCEPTIBLE TO MIX OUT  
AND/OR DEW DEPLETION, SO FOG COVERAGE REMAINS UNCERTAIN. SUSPECT  
THAT THE BEST OVERALL FOG POTENTIAL WILL REMAIN CONFINED TO  
RIVER VALLEYS & OTHER LOW-LYING SPOTS, BUT HAVE INCLUDED BROADER  
MENTIONS AREAWIDE IN THE AFTERNOON UPDATE. WILL BE MONITORING  
VISIBILITY TRENDS INTO THE OVERNIGHT. SLOW DOWN, USE LOW BEAM  
HEADLIGHTS, AND ALLOW FOR EXTRA FOLLOWING DISTANCE IF  
ENCOUNTERING AREAS OF FOG ON THE ROADS.  
 
QUIGLEY  
 
 
   
LONG TERM  
 
ISSUED 1200 PM CDT SUN AUG 23 2026  
 
TUESDAY THROUGH SUNDAY:  
 
SYNOPSIS: HIGH PRESSURE WILL CONTINUE TO SHIFT EAST OF THE REGION ON  
TUESDAY, WITH SOUTHERLY RETURN FLOW ALLOWING FOR GRADUAL MOISTURE  
RETURNS AND SLIGHT INCREASES IN HUMIDITY. THE NEXT UPPER DISTURBANCE  
AND SURFACE FRONT WILL DRIFT INTO THE WESTERN GREAT LAKES FROM THE  
CANADIAN PRAIRIES TUESDAY EVENING THROUGH WEDNESDAY, BRINGING THE  
NEXT CHANCES FOR SHOWERS AND THUNDERSTORMS TO SOUTHERN WISCONSIN. A  
NEW AREA OF HIGH PRESSURE WILL MOVE INTO THE WESTERN GREAT LAKES  
DURING THE SECOND HALF OF THE WEEK, LEADING TO PLEASANT AND MOSTLY  
DRY WEATHER CONDITIONS THURSDAY INTO FRIDAY. THE HIGH WILL SHIFT  
EAST BY SATURDAY, WITH RETURNING SOUTHERLY FLOW LEADING TO STEADY  
INCREASES IN HUMIDITY THROUGH THE REMAINDER OF NEXT WEEKEND.  
CONCURRENT INCREASES IN ZONAL UPPER LEVEL FLOW, IN ADDITION TO  
EMBEDDED SHORTWAVES, WILL SUPPORT THE NEXT SHOWER AND STORM CHANCES  
WITHIN THE RETURNING MOISTURE. SATURDAY NIGHT INTO SUNDAY IS THE  
CURRENTLY FAVORED WINDOW FOR STORMS IN SOUTHERN WISCONSIN, WITH MORE  
PRECISE TIMING CLARIFYING THROUGH THIS WEEK.  
 
TUESDAY EVENING THROUGH WEDNESDAY: STILL ANTICIPATING PERIODS OF  
SHOWERS AND STORMS ACROSS SOUTHERN WISCONSIN AS AN UPPER WAVE &  
ATTENDANT SURFACE COLD FRONT MOVE THROUGH THE WESTERN GREAT  
LAKES. GENERAL IDEA OF INITIAL (LIKELY ELEVATED) STORMS WITHIN  
AN INCREASING WARM ADVECTION REGIME TUESDAY EVENING/NIGHT,  
FOLLOWED BY A WINDOW OF SURFACE-BASED STORM POTENTIAL ALONG THE  
PASSING COLD FRONT WEDNESDAY AFTERNOON, REMAINS ON TRACK IN THIS  
FORECAST. LATEST SIX HOURLY PRECIP PROBS REFLECT THESE  
EXPECTATIONS. WHETHER OR NOT ANY OF THIS ACTIVITY REACHES SEVERE  
LEVELS REMAINS LESS CERTAIN, HOWEVER, LARGELY DUE TO THE  
CURRENTLY PROGGED TIMING OF THE BEST SYNOPTIC-SCALE ASCENT.  
GLOBAL & LONGER-RANGE MESOSCALE GUIDANCE IS RELATIVELY INSISTENT  
ON A TUESDAY OVERNIGHT/EARLY DAY WEDNESDAY PASSAGE OF THE UPPER  
WAVE & SURFACE FRONT, WHICH WOULD BE MISALIGNED WITH PEAK  
SURFACE HEATING & THE BEST INSTABILITY. NEVERTHELESS, PREVAILING  
DEEP LAYER SHEAR WILL BE SUPPORTIVE OF MORE ORGANIZED STORM  
DEVELOPMENT THROUGH THIS TIME FRAME, WITH ANY COMBINATION OF  
FACTORS PROMOTING INCREASED INSTABILITY LEADING TO HIGHER  
POTENTIAL FOR A FEW SEVERE STORMS WITH HAIL AND GUSTY WINDS.  
WILL BE MONITORING SETUP AND TIMING DETAILS CLOSELY OVER THE  
NEXT 24-36 HOURS.  
 
SATURDAY NIGHT THROUGH SUNDAY: A SECOND WINDOW FOR SHOWERS AND  
STORMS OPENS AS LOW LEVEL MOISTURE DEEPENS & THE MID-UPPER PATTERN  
BECOMES MORE ENERGETIC. MORE PRECISE DETAILS WILL CLARIFY THROUGH  
THIS WEEK, THOUGH IT DOES APPEAR THAT PERIODS OF STORMS WILL BE  
AROUND THE REGION AS THE NOSE OF THE LOW LEVEL JET APPROACHES AND  
ULTIMATELY FOLDS OVER SOUTHERN WISCONSIN. GLOBAL ENSEMBLE  
GUIDANCE IS IN RELATIVELY SOUND AGREEMENT REGARDING LOW LEVEL  
JET EVOLUTION & PLACEMENT, PROVIDING FURTHER CONFIDENCE FOR  
PERIODS OF STORMS DURING THIS TIME FRAME. A BROAD OVERLAP OF  
SUFFICIENT SHEAR AND INSTABILITY MAKES THIS A PERIOD TO MONITOR  
FOR ORGANIZED/STRONGER THUNDERSTORMS, THOUGH WHETHER THESE  
PARAMETERS COME TOGETHER TO REALIZE ANY POTENTIAL WILL DEPEND ON  
SMALLER-SCALE FEATURES & TIMING NOT YET CAPTURED BY AVAILABLE  
GUIDANCE. WILL BE MONITORING TRENDS & PROVIDING ADDITIONAL INFO  
AS THIS PORTION OF THE PERIOD DRAWS CLOSER.  
 
QUIGLEY  
 
 
   
AVIATION  
 
ISSUED 709 PM CDT SUN AUG 23 2026  
 
LARGELY VFR CONDITIONS THROUGH THE PERIOD. WITH SKIES CLEARING  
THIS EVENING AND WINDS DIMINISHING, THE ONE POTENTIAL FOR LOWER  
CEILINGS AND VISIBILITIES WILL BE WITH ANY FOG THAT DEVELOPS  
AFTER MIDNIGHT. THERE IS UNCERTAINTY IN HOW WIDESPREAD THE  
PATCHY FOG COULD BECOME, BUT VISIBILITIES COULD FALL TO AROUND  
2-4 SM. TERMINALS IN LOW LYING AREAS OR RIVER VALLEYS (LNR AND  
JVL) WILL HAVE THE BEST POTENTIAL FOR FOG DEVELOPMENT. VFR  
CONDITIONS ARE EXPECTED TO RETURN SHORTLY AFTER SUNRISE. FAIR  
WEATHER CUMULUS CLOUDS ARE EXPECTED TO RETURN LATE MORNING  
THROUGH THE EVENING MONDAY. THE FEW TO SCATTERED CLOUD DECK IS  
EXPECTED TO BE AROUND 4-6 KFT.  
 
LIGHT AND VARIABLE WINDS TONIGHT WILL BECOME LIGHT NORTHWESTERLY  
WINDS MONDAY. A LAKE BREEZE IS EXPECTED TO DEVELOP DURING THE  
EARLY EVENING HOURS WHICH WILL TURN WINDS TO THE NORTHEAST THEN  
EAST FOR LAKESHORE TERMINALS. LIGHT AND VARIABLE WINDS ARE  
EXPECTED AGAIN MONDAY NIGHT.  
 
PATTERSON  
 
 
   
MARINE  
 
ISSUED 1200 PM CDT SUN AUG 23 2026  
 
SCATTERED SHOWER CHANCES CONTINUE OVER THE NORTHERN THIRD OF LAKE  
MICHIGAN THIS AFTERNOON, WITH A FEW WATERSPOUTS POSSIBLE. 1004 MB  
LOW PRESSURE IS CENTERED NEAR THE ONTARIO-QUEBEC BORDER, RESULTING  
IN BREEZY NORTHWEST WINDS ACROSS THE OPEN WATERS OF LAKE MICHIGAN.  
THE BREEZY WINDS WILL CONTINUE THROUGH TONIGHT AS THE LOW LINGERS IN  
THE SAME GENERAL VICINITY. EXPECTING MOST GUSTS TO REMAIN IN THE 25-  
30 KNOT RANGE, THOUGH A FEW GUSTS APPROACHING GALE FORCE ARE  
POSSIBLE OVER THE NORTHERN THIRD OF THE LAKE. GIVEN THE BRIEF &  
ISOLATED NATURE OF ANY SUCH GUSTS, NOT ANTICIPATING THE NEED FOR ANY  
GALE HEADLINES, BUT WILL BE MONITORING TRENDS. 1020 MB HIGH PRESSURE  
WILL STEADILY BUILD INTO THE UPPER MISSISSIPPI VALLEY TODAY,  
REACHING THE WATERS BY MONDAY AFTERNOON. THE HIGH'S ARRIVAL WILL  
LEAD TO DECREASING WINDS, WITH CONDITIONS BECOMING LIGHT AND  
VARIABLE BY MONDAY EVENING.  
 
LIGHT AND VARIABLE WINDS WILL CONTINUE MONDAY NIGHT WITH HIGH  
PRESSURE LINGERING IN THE VICINITY. THE HIGH WILL SHIFT EAST INTO  
ONTARIO BY TUESDAY, RESULTING IN A SOUTH-SOUTHWEST WIND SHIFT ACROSS  
THE WATERS. 1005 MB LOW PRESSURE WILL APPROACH FROM THE NORTHERN  
GREAT PLAINS TUESDAY NIGHT INTO WEDNESDAY, REINFORCING THE SOUTH-  
SOUTHWESTERLY WIND PATTERN. THE LOW WILL CROSS LAKE MICHIGAN DURING  
THE SECOND HALF OF THE DAY WEDNESDAY, BRINGING A BREEZY NORTHWEST  
WIND SHIFT. GALES ARE NOT EXPECTED AS THIS OCCURS. SHOWERS AND  
THUNDERSTORMS WILL ACCOMPANY THE APPROACHING/PASSING SURFACE LOW  
TUESDAY NIGHT INTO WEDNESDAY AFTERNOON. IT REMAINS TOO EARLY TO TELL  
IF ANY OF THESE STORMS COULD BE SEVERE, WITH TRENDS BEING MONITORED  
THROUGH THE BEGINNING OF THIS WEEK. THE NEXT AREA OF 1018 MB HIGH  
PRESSURE WILL GRADUALLY BUILD TOWARD LAKE MICHIGAN FROM THE NORTHERN  
GREAT PLAINS WEDNESDAY NIGHT THROUGH FRIDAY, BRINGING SLOWLY  
DECREASING WINDS.  
 
A BRIEF PERIOD OF SMALL CRAFT ADVISORY CONDITIONS REMAINS POSSIBLE  
TUESDAY AFTERNOON & EVENING AHEAD OF APPROACHING LOW PRESSURE,  
PARTICULARLY TO THE NORTH OF NORTH POINT. WHETHER THESE CONDITIONS  
WILL BE SUSTAINED & WIDESPREAD ENOUGH FOR HEADLINES REMAINS  
UNCERTAIN AT THIS TIME, WITH TRENDS BEING MONITORED INTO TOMORROW.  
SHOWERS AND THUNDERSTORMS RETURN TO NEARSHORE ZONES TUESDAY NIGHT  
INTO WEDNESDAY ALONG/AHEAD OF AN APPROACHING COLD FRONT.  
 
QUIGLEY  
 
 
   
MKX WATCHES/WARNINGS/ADVISORIES  
 
WI...NONE.  
LM...NONE.  
 
 
 
 
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