639  
FXUS63 KMKX 181214 AAA  
AFDMKX  
 
AREA FORECAST DISCUSSION...UPDATED  
NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI  
714 AM CDT FRI SEP 18 2026  
   
KEY MESSAGES
 
 
- BRIEF HIGH SWIMMING RISK TODAY AT MILWAUKEE, RACINE, AND  
KENOSHA COUNTY BEACHES. MORE PROLONGED HIGH SWIMMING RISK  
EXPECTED AT ALL LAKE MICHIGAN BEACHES TONIGHT THROUGH THE  
WEEKEND.  
 
- SCATTERED SHOWERS AND RUMBLES DURING THE DAYTIME HOURS TODAY.  
NO HAZARDS ARE EXPECTED.  
 
- WIDESPREAD SHOWERS AND STORMS TONIGHT INTO SATURDAY MORNING  
(~10 PM TO 10 AM PEAK). LOCALLY HEAVY RAINFALL AND FLOODING  
IMPACTS ARE POSSIBLE. FLOOD WATCH IS NOW IN EFFECT OVER THE  
SOUTHWEST PART OF THE AREA.  
 
- MORE SHOWERS AND STORMS POSSIBLE SATURDAY AFTERNOON AND  
EVENING. STORMS COULD PRODUCE ADDITIONAL HEAVY DOWNPOURS,  
THOUGH POTENTIAL FOR FLOODING IMPACTS IS LOWER COMPARED TO  
TONIGHT AND SATURDAY MORNING.  
 
- OFF AND ON CHANCES FOR LIGHTER RAIN SUNDAY INTO MONDAY.  
TRENDING DRIER TOWARD THE MIDDLE OF NEXT WEEK.  
 

 
   
UPDATE
 
 
ISSUED 714 AM CDT FRI SEP 18 2026  
 
FOG HAS CONTINUED TO PUSH WEST AND OUT OF THE AREA, WITH THE LOW  
CLOUDS IN PARTS OF THE AREA LINGERING FOR ANOTHER FEW HOURS OR  
SO. SOME LAKE EFFECT CLOUDS MAY LINGER TOWARD SHEBOYGAN THIS  
MORNING. OTHERWISE, HIGH CLOUDS WILL MOVE EAST INTO THE AREA  
TODAY. THERE IS A GOOD AMOUNT OF DRY AIR TO BATTLE THE SHOWERS  
FROM THE WEST, SO WILL HAVE TO WATCH TRENDS AND ADJUST THE  
FORECAST AS NEEDED.  
 
THE MAIN THING TO WATCH FOR THE HEAVY RAINFALL LATER TONIGHT  
INTO SATURDAY MORNING WILL BE WHERE THE LOW LEVEL JET NOSE,  
FOCUSED WARM AIR ADVECTION AND LOW LEVEL FRONTOGENESIS SET UP.  
THIS SHOULD BE WHERE THE HEAVIEST RAINFALL AMOUNTS OCCUR, WITH  
THE HIGH PRECIPITABLE WATER VALUES AND MOIST ADIABATIC SOUNDING  
PROFILES WITH TALL SKINNY CAPE. FOR NOW, THE FLOOD WATCH COVERS  
THE MOST PROBABLE AREA FOR HEAVY RAINFALL AND SOME FLOODING  
IMPACTS. WE WILL SEE IF AN EXPANSION EAST IS NEEDED IN LATER  
FORECASTS.  
 
WOOD  
 

 
   
SHORT TERM
 
 
ISSUED 1159 PM CDT THU SEP 17 2026  
 
CURRENT OVERNIGHT THROUGH SUNDAY:  
 
SYNOPSIS/MESOANALYSIS: LOW STRATUS CLOUDS AND FOG POCKETS ARE  
LINGERING ACROSS PARTS OF SOUTHERN WISCONSIN LATE THIS EVENING AS  
LOW LEVEL MOISTURE REMAINS STAGNANT REGIONALLY. ALREADY EVIDENT IN  
OBS TRENDS OVER THE NORTH-CENTRAL PART OF THE STATE, EXPECT THAT THE  
RESPONSIBLE MOISTURE WILL STEADILY BE FLUSHED OUT THROUGH THE SECOND  
HALF OF THE OVERNIGHT AS HIGH PRESSURE BUILDS TO THE NORTH OF LAKE  
SUPERIOR. SAID HIGH IS FORECAST TO BUILD TOWARD THE ONTARIO-QUEBEC  
BORDER THROUGH SATURDAY MORNING, MAINTAINING GENERALLY EASTERLY FLOW  
ACROSS SOUTHERN WISCONSIN. FURTHER WEST, AN UPPER DISTURBANCE IS  
EJECTING INTO THE NORTH-CENTRAL PLAINS, WITH ATTENDANT SURFACE  
CYCLOGENESIS OCCURRING OVER NORTHEAST COLORADO. THE NEWLY-FORMING  
SURFACE LOW WILL TRACK INTO THE MISSOURI VALLEY FRIDAY NIGHT,  
ULTIMATELY MOVING NEAR OR JUST SOUTH OF THE WISCONSIN-ILLINOIS  
BORDER ON SATURDAY. A COMBINATION OF WARM ADVECTION & FRONTOGENESIS  
NORTH OF THE LOW, IN ADDITION TO EMBEDDED SHORTWAVES IN THE FLOW  
ALOFT, WILL DRIVE TWO PRIMARY PERIODS OF SHOWERS & STORMS FRIDAY  
NIGHT INTO SATURDAY MORNING & SATURDAY EVENING/NIGHT. HEAVY  
DOWNPOURS WILL BE POSSIBLE IN ANY STORMS, WITH LOCALLY HEAVY  
RAINFALL AND FLOODING IMPACTS POSSIBLE FRIDAY NIGHT/SATURDAY  
MORNING. SEVERE WEATHER POTENTIAL IS LOW IN ALL BOUTS OF STORMS.  
ADDITIONAL LIGHTER SHOWERS MAY CONTINUE INTO SUNDAY, WITH MINIMAL  
IMPACTS ANTICIPATED.  
 
REMAINDER OF OVERNIGHT: WILL BE WATCHING FOR AREAS OF LINGERING FOG  
INTO THE PREDAWN HOURS. HAVE CARRIED MENTIONS IN THE NEAR-TERM  
WEATHER GRIDS, WITH THE THINKING BEING THAT IMPROVEMENTS WILL  
STEADILY OCCUR TOWARD DAYBREAK WITH MOISTURE SHOVING SOUTH AND WINDS  
ATTEMPTING TO PICK UP. WARM-ADVECTION DRIVEN SHOWERS & STORMS  
AFFILIATED WITH THE PROGRESSING SURFACE LOW WILL CONTINUE TO MIGRATE  
EASTWARD TOWARD THE MISSISSIPPI VALLEY, BUT ARE EXPECTED TO STAY  
WEST OF THE AREA THROUGH SUNRISE.  
 
FRIDAY: CONTINUE TO EXPECT A BRIEF PERIOD OF HIGH SWIMMING RISK  
CONDITIONS THROUGH THE MORNING HOURS. A BEACH HAZARDS STATEMENT  
REMAINS IN EFFECT AT MILWAUKEE, RACINE, AND KENOSHA COUNTY BEACHES  
BETWEEN 7 AM AND 2 PM. EXERCISE EXTREME CAUTION IF HEADING LAKESIDE,  
AND BE SURE TO STAY AWAY FROM DANGEROUS AREAS LIKE BREAKWATERS AND  
PIERS. WITH BROAD WARM ADVECTION GRADUALLY INCREASING FROM WEST TO  
EAST AHEAD OF THE APPROACHING SURFACE LOW, DO ANTICIPATE THAT A  
SCATTERING OF SHOWERS & EMBEDDED THUNDER WILL WORK INTO SOUTHERN  
WISCONSIN FROM MID-MORNING INTO THE AFTERNOON HOURS. SCATTERED  
PRECIP COVERAGE, ALONG WITH LIMITED INSTABILITY, SHOULD KEEP HEAVY  
RAINFALL CONCERNS MINIMAL IN ANY DAYTIME ACTIVITY. KEEP AN EYE ON  
THE RADAR IF PLANNING TO BE OUTDOORS.  
 
FRIDAY EVENING INTO SATURDAY MORNING: WIDESPREAD SHOWERS AND STORMS  
WILL MOVE INTO SOUTHERN WISCONSIN AS LOW PRESSURE MAKES ITS  
APPROACH. EXPECT WIDESPREAD COVERAGE TO BE MAINTAINED THROUGH  
MOST OR ALL OF THIS TIME FRAME THANKS TO A SEASONABLY STRONG LOW  
LEVEL JET AND ATTENDANT CONVEYOR OF WARM ADVECTION IN THE  
925-850 MB LAYER. ARRIVAL OF THE LOW LEVEL JET WILL ALSO BRING  
AN UNSEASONABLY MOIST AIR MASS CHARACTERIZED BY PRECIPITABLE  
WATER VALUES NEAR OR SLIGHTLY ABOVE 2 INCHES (USING 00Z OAX RAOB  
AS A PROXY), WHICH WILL BE CONDUCIVE FOR ENHANCED RAINFALL  
RATES IN EMBEDDED CONVECTION. SAID HEAVY RATES COULD LEAD TO  
NUISANCE HYDRO IMPACTS (URBAN/SMALL STREAM FLOODING, PONDING OF  
WATER, RISES ON RIVERS/CREEKS) AREAWIDE, WITH SOME POTENTIAL FOR  
FLASH FLOODING IN LOCATIONS WHERE STORMS TRACK REPEATEDLY. HAVE  
NOTED RUN-TO-RUN CONSISTENCIES IN CAM GUIDANCE BACK TO 12Z THIS  
MORNING SUGGESTING THAT SOME TRAINING WILL OCCUR, WITH THE  
MOST-FAVORED ZONE(S) FOR TRAINING LIKELY MATERIALIZING WHERE THE  
LOW LEVEL JET INTERSECTS WITH FRONTOGENESIS BANDS IN THE  
925-850 MB LAYER. GIVEN MODELING CONSISTENCIES AND THE FAVORABLE  
ENVIRONMENTAL FACTORS, HAVE ISSUED A FLOOD WATCH BETWEEN 1 AM &  
1 PM SATURDAY FOR THE SOUTHWEST CORNER OF THE CWA, WHERE AN  
OVERLAP OF HIGH PRECIPITABLE WATERS & LLJ-FGEN INTERSECTION IS  
CURRENTLY EXPECTED TO BE IN PLACE. HAVE REFRAINED FROM CARRYING  
THE WATCH ANY FURTHER NORTH OR EAST, AS LINGERING INFLUENCES  
FROM DEPARTING HIGH PRESSURE MAY IMPEDE THE MOST FAVORABLE  
ENVIRONMENTAL CONDITIONS FROM PROGRESSING BEYOND THE EXISTING  
WATCH AREA. WILL NEVERTHELESS BE MONITORING FOR CHANGES, AS  
SMALL CHANGES COULD CALL FOR CHANGES IN WATCH AREA & START/END  
TIMES. COLLECTIVELY STILL ANTICIPATING 1-3" OF RAIN AREAWIDE  
DURING THIS PORTION OF THE PERIOD, WITH HIGHER TOTALS IN THE  
3-5"+ RANGE POSSIBLE IN AREAS OF TRAINING (IN & NEAR THE WATCH  
AREA).  
 
SATURDAY EVENING & NIGHT: WILL BE WATCHING FOR ADDITIONAL  
SHOWER/STORM DEVELOPMENT WITH THE SURFACE LOW STILL IN THE VICINITY  
& MOISTURE REMAINING ELEVATED. COULD SEE MORE HEAVY DOWNPOURS IN  
STORMS, THOUGH CURRENT GUIDANCE POINTS TOWARD THE BEST POTENTIAL FOR  
TRAINING & FLOODING HAZARDS OVER NORTH-CENTRAL ILLINOIS. WILL BE  
MONITORING TRENDS AND PROVIDING UPDATES AS NECESSARY.  
 
QUIGLEY  
 

 
   
LONG TERM
 
 
ISSUED 1159 PM CDT THU SEP 17 2026  
 
SUNDAY NIGHT THROUGH THURSDAY:  
 
THE EAST-WEST SURFACE BAROCLINIC ZONE IS FORECAST TO REMAIN STALLED  
OVER NORTHERN IL/IN INTO MONDAY, WITH AN APPROACHING 500MB SHORTWAVE  
PHASING WELL ENOUGH WITH IT TO MERIT SOME CONTINUED CHANCES FOR  
LIGHT RAINFALL OVER SOUTHERN WI. OUR POSITIONING NORTH OF THE  
SURFACE BOUNDARY OUGHT TO LIMIT THUNDER POTENTIAL AND KEEP THE RAIN  
SHOWERS RELATIVELY LIGHT FOR MONDAY.  
PREDOMINANTLY DRY WEATHER WITH ONLY SLIGHT CHANCES FOR RAIN INTO  
TUESDAY AS THE SURFACE FRONTAL ZONE SAGS FURTHER SOUTH.  
PREDOMINANTLY DRY WEATHER SHOULD THEN CONTINUE THROUGH MIDWEEK AS  
HIGH PRESSURE REMAINS DOMINANT OVER THE REGION.  
 
THE AFOREMENTIONED 500MB TROUGH FROM MONDAY MAY STALL NEARBY AND  
CLOSE OFF INTO A CUTOFF UPPER-LOW MIDWEEK NEXT WEEK, A PATTERN THAT  
OFTEN THROWS A WRENCH INTO MODEL PREDICTABILITY. THAT SAID, MODELS  
HAVE A STABLE SOLUTION ON A STRONG HIGH PRESSURE SYSTEM OVER  
SOUTHERN ONTARIO CANADA EARLY NEXT WEEK, SHIFTING EAST INTO QUEBEC  
MIDWEEK, WHICH LEADS US TO EXPECT A PERSISTENT NORTHEAST BREEZE AND  
COOL WEATHER THROUGH THE PERIOD (HIGHS IN THE 60S, LOWS AROUND 50).  
 
AT THE VERY END OF OUR FORECAST RUN (LATER NEXT WEEK), WE BEGIN TO  
SEE RIDGING IN THE JET, SLOWLY BUILDING EAST INTO THE UPPER MIDWEST.  
TEMPERATURES SHOULD LEAN ABOVE SEASONAL NORMS AT SOME POINT LATE  
NEXT WEEK INTO THE SUBSEQUENT WEEKEND.  
 
SHEPPARD  
 

 
   
AVIATION
 
 
ISSUED 714 PM CDT FRI SEP 18 2026  
 
FOG WITH 1 TO 3 MILE VISIBILITY HAS CONTINUED TO PUSH WEST AND  
OUT OF THE AREA, WITH THE LOW CLOUDS OF 1500 TO 2500 FEET AGL  
OR SO IN PARTS OF THE AREA LINGERING FOR ANOTHER FEW HOURS OR  
SO. SOME LAKE EFFECT CLOUDS AROUND 2500 FEET AGL MAY LINGER  
TOWARD SHEBOYGAN THIS MORNING. OTHERWISE, HIGH CLOUDS WILL MOVE  
EAST INTO THE AREA TODAY. THERE IS A GOOD AMOUNT OF DRY AIR TO  
BATTLE THE SHOWERS FROM THE WEST, SO WILL HAVE TO WATCH TRENDS  
AND ADJUST THE FORECAST AS NEEDED.  
 
EAST WINDS WILL BECOME GUSTY TODAY, WITH MORE NORTHEAST WINDS  
NEAR THE LAKE. WINDS WILL REMAIN GENERALLY EAST TONIGHT AND STAY  
GUSTY, BECOMING MORE EAST SOUTHEAST TO EAST ON SATURDAY.  
CEILINGS SHOULD REMAIN VFR CATEGORY TODAY INTO THIS EVENING,  
BEFORE DROPPING TO BELOW 1000 FEET AGL LATER TONIGHT INTO  
SATURDAY. VISIBILITY WITH THE RAIN SHOULD BE IN THE 1 TO 4 MILE  
RANGE.  
 
WOOD  
 

 
   
MARINE
 
 
ISSUED 1159 PM CDT THU SEP 17 2026  
 
A NEW AREA OF 1030 MB HIGH PRESSURE WILL SHIFT FROM THE CANADIAN  
GREAT PLAINS INTO ONTARIO TONIGHT, MAINTAINING EAST-NORTHEAST WINDS  
ACROSS LAKE MICHIGAN. 1012 MB LOW PRESSURE WILL DEVELOP NEAR THE  
MISSOURI RIVER FRIDAY AFTERNOON, MOVING OVER OR JUST SOUTH OF WATERS  
DURING THE DAY ON SATURDAY. WINDS WILL VEER EAST-SOUTHEASTERLY AHEAD  
OF THE LOW, BECOMING GUSTY AT POINTS. A FEW GUSTS COULD APPROACH  
GALE THRESHOLDS, PARTICULARLY ON FRIDAY NIGHT AND SATURDAY MORNING.  
NOT EXPECTING ANY BORDERLINE GALES TO BE PROLONGED OR WIDESPREAD  
ENOUGH TO WARRANT GALE WARNINGS, BUT WILL CONTINUE TO MONITOR  
TRENDS. AREAS OF WIDESPREAD SHOWERS & STORMS WILL ACCOMPANY THE  
APPROACHING/PASSING AREA OF LOW PRESSURE FRIDAY NIGHT THROUGH AT  
LEAST SATURDAY NIGHT, WITH WIDESPREAD SEVERE WEATHER NOT EXPECTED AT  
THIS TIME.  
 
WINDS WILL TREND NORTHEASTERLY SUNDAY THROUGH MONDAY NIGHT AS THE  
AFOREMENTIONED AREA OF LOW PRESSURE SLOWLY MOVES INTO THE OHIO RIVER  
VALLEY. ADDITIONAL RAIN SHOWERS WILL ACCOMPANY THE PASSING LOW, WITH  
THUNDER AND SEVERE WEATHER HAZARDS APPEARING UNLIKELY AT THIS TIME.  
1032 MB HIGH PRESSURE WILL CONCURRENTLY SLIDE INTO ONTARIO FROM THE  
CANADIAN GREAT PLAINS, WITH A COMPACTED PRESSURE GRADIENT ALLOWING  
FOR GUSTY WINDS THROUGH MOST OF THE LATE WEEKEND/EARLY WEEK TIME  
FRAME. SIMILAR TO SATURDAY, GUSTS COULD OCCASIONALLY APPROACH GALE  
THRESHOLDS DURING THE SUNDAY-MONDAY NIGHT TIME FRAME, WITH  
CONDITIONS NOT EXPECTED TO BE WIDESPREAD ENOUGH FOR GALE WARNINGS AT  
THIS TIME. WINDS WILL STEADILY TAPER TUESDAY THROUGH WEDNESDAY AS A  
NEW AREA OF 1026 MB HIGH PRESSURE BUILDS INTO NORTHERN WISCONSIN.  
 
A BRIEF PERIOD OF ELEVATED WAVE HEIGHTS IS STILL EXPECTED FRIDAY  
MORNING IN NEARSHORE ZONES, WITH A SMALL CRAFT ADVISORY IN EFFECT  
BETWEEN 7 AM AND 2 PM FROM MILWAUKEE SOUTH TO WINTHROP HARBOR. WAVE  
HEIGHTS WILL DECREASE THROUGH THE SECOND HALF OF FRIDAY AFTERNOON  
AND EARLY EVENING. GUSTS AND WAVE HEIGHTS WILL INCREASE ONCE MORE  
LATE FRIDAY EVENING, AND WILL REMAIN NEAR OR ABOVE SMALL CRAFT  
ADVISORY THRESHOLDS THROUGH THE ENTIRETY OF THE WEEKEND INTO EARLY  
NEXT WEEK. WILL BE COVERING THIS POTENTIAL WITH A NEW SMALL CRAFT  
ADVISORY FOLLOWING EXPIRATION OF THE ONGOING ONE FRIDAY AFTERNOON. A  
FEW GUSTS COULD OCCASIONALLY APPROACH GALE FORCE DURING THE  
PROLONGED PERIOD OF ADVISORY CONDITIONS, THOUGH THEY ARE EXPECTED TO  
REMAIN ISOLATED AND BRIEF ENOUGH TO PRECLUDE THE NEED FOR GALE  
WARNINGS. THUNDERSTORMS WILL MOVE IN FRIDAY EVENING AND SATURDAY  
MORNING, WITH SEVERE WEATHER NOT EXPECTED.  
 
QUIGLEY  
 

 
   
MKX WATCHES/WARNINGS/ADVISORIES
 
 
WI...FLOOD WATCH...WIZ056-WIZ057-WIZ062-WIZ063-WIZ067-WIZ068-  
WIZ069...1 AM SATURDAY TO 1 PM SATURDAY.  
 
BEACH HAZARDS STATEMENT...WIZ066-WIZ071-WIZ072 UNTIL 2 PM  
FRIDAY.  
 
LM...SMALL CRAFT ADVISORY...LMZ645-LMZ646 UNTIL 2 PM FRIDAY.  
 

 
 

 
 
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