520
FXUS63 KMKX 040013
AFDMKX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI
713 PM CDT THU SEP 3 2026
KEY MESSAGES
- PERIODS OF SHOWERS AND STORMS WILL BE POSSIBLE THROUGH FRIDAY,
WITH TONIGHT'S ROUND CAPABLE OF PRODUCING STRONG TO SEVERE
THUNDERSTORMS. DAMAGING WINDS AND HEAVY RAINFALL ARE EXPECTED
TO BE THE MAIN HAZARDS.
- DRIER WEATHER EXPECTED FOR THE WEEKEND INTO EARLY NEXT WEEK,
WITH WARM AND HUMID CONDITIONS PERSISTING.
UPDATE
ISSUED 704 PM CDT THU SEP 3 2026
RAIN SHOULD HOLD OFF THIS EVENING, BUT WE ARE CURRENTLY
MONITORING WEST CENTRAL MN AS THE LOCATION WHERE THUNDERSTORMS
MAY DEVELOP AND THEN TRACK INTO WISCONSIN DURING THE OVERNIGHT
HOURS. LOCAL OBS AND MESOANALYSIS DATA INDICATE THAT A PRIMARY
AND SECONDARY WARM FRONT ARE DRAPED OVER THE UP OF MICHIGAN AND
THROUGH CENTRAL WISCONSIN, RESPECTIVELY, AND BOTH CONNECT TO AN
AREA OF LOW PRESSURE NEAR FARGO, SD.
THETA-E ADVECTION HAS BEEN NOTED TO BE STRONGEST IN THIS AREA
LATE THIS AFTERNOON INTO THE EARLY EVENING. AS A LOW LEVEL JET
KICKS IN DURING THE OVERNIGHT HOURS, THE THETA-E ADVECTION OVER
THE BOUNDARIES SHOULD INCREASE IN STRENGTH, LEADING TO MORE
WIDESPREAD CONVECTIVE INITIATION. THIS CONVECTION IS THEN
EXPECTED TO TRACK ESE ALONG THE SFC WARM FRONT/CAPE GRADIENT. IF
THIS SCENARIO PLAYS OUT, THE NE HALF OF OUR CWA WOULD BE IN LINE
TO SEE A COMPLEX OF STORMS ROLL THROUGH THE AREA BETWEEN 5AM TO
8AM FRIDAY MORNING, WHILE THE SW HALF OF THE CWA SEES MORE HIT
OR MISS STORMS. DAMAGING WINDS WOULD BE THE MAIN SEVERE WEATHER
HAZARDS, THOUGH HEAVY RAIN AND LOCALIZED FLOODING WOULD ALSO BE
POSSIBLE GIVEN THE HIGH PWATS FROM 1.8 TO 2 INCHES OVER THE
REGION, AND THE HIGH LIKELIHOOD THAT STORMS WILL TRACK
REPEATEDLY OVER THE SAME AREAS OVERNIGHT INTO FRIDAY MORNING.
ONE POTENTIAL FAILURE MODE OR SOMETHING THAT COULD CHANGE THE
COURSE OF THE OVERNIGHT CONVECTION IS THE CURRENT CONVECTION
THAT IS ONGOING OVER NORTH CENTRAL WI. THIS COULD EITHER PUSH
THE INSTABILITY GRADIENT SOUTHWARD OR OVERTURN FAVORABLE
INSTABILITY OUT AHEAD OF THE EXPECTED STORMS. THIS LENDS A BIT
OF UNCERTAINTY TO THE EXACT TRACK OF THE STORMS OVERNIGHT. THESE
STORMS MAY ALSO ARRIVE IN EAST CENTRAL WISCONSIN SOMETIME THIS
EVENING IF THEY HOLD TOGETHER.
CMILLER
SHORT TERM
ISSUED 326 PM CDT THU SEP 3 2026
TONIGHT THROUGH FRIDAY NIGHT:
WE HAVE A SURFACE FRONTAL BOUNDARY DRAPED ACROSS SOUTHERN WI
THIS AFTERNOON. IT HAS NOT MOVED MUCH SINCE EARLY THIS MORNING.
WE HAVE SOUTHERLY WINDS AND HIGH DEWPOINTS (GREATER THAN 72F)
SOUTH OF A LINE FROM THE DELLS TO WATERTOWN TO MENOMONEE FALLS,
AND A SLIGHTLY DIFFERENT AIR MASS NORTH OF THERE (DEWPOINTS
67-72 AND LIGHTER EAST-NORTHEAST WINDS). THIS BOUNDARY WILL
CONTINUE TO CARRY A CHANCE FOR SHOWERS AND A FEW THUNDERSTORMS
THROUGH LATE EVENING, DESPITE THE MESO MODEL FORECAST REFLECTIVITY
FIELD SHOWING THAT AREA CLEAR.
MEANWHILE, THE LOW LEVEL JET WILL RAMP UP AGAIN THIS EVENING AND
LIKELY NOSE ALL THE WAY INTO NORTHERN WI AND THE NORTHERN
PORTIONS OF EAST CENTRAL WI (BETWEEN SHEBOYGAN AND GREEN BAY).
THIS WILL BE OUR AREA TO WATCH FOR SCATTERED THUNDERSTORMS TO
DEVELOP BETWEEN 8 AND 10 PM, AND A FEW COULD BE STRONG. THIS
WOULD BE IN AN ENVIRONMENT FAVORABLE FOR GUSTY WINDS
(DOWNBURSTS) AND HAIL WITH MODEST CAPE AND SHEAR. THIS CLUSTER
OF STORMS IS EXPECTED TO SLIDE SOUTHEAST AND COULD CLIP EAST
CENTRAL WI INCLUDING FOND DU LAC AND SHEBOYGAN.
THE STORMS THAT JUST DEVELOPED AND TRACKED THROUGH GRAND FORKS,
ND THIS AFTERNOON ARE WHAT WE ARE WATCHING FOR OUR OVERNIGHT
THUNDERSTORM/SEVERE CHANCES. THE BROKEN LINE OF STORMS SHOULD
ARRIVE IN CENTRAL WI AROUND 1 AM (THEY MAY CATCH UP OR MERGE
WITH THE LLJ STORMS IN EAST CENTRAL WI). THE 18Z HRRR IS NOW
TRACKING THIS LINE FARTHER NORTH ACROSS NORTHERN WI AND NOT
THROUGH EAST CENTRAL/SOUTHEAST WI. THIS MIGHT BE PICKING UP ON A
LLJ AND CAPE GRADIENT THAT IS FARTHER NORTH THAN WHAT THE 12Z
MODELS AND ESPECIALLY THE 06Z MODELS WERE PICKING UP ON.
IF THIS LINE OF STORMS TRACKS INTO SOUTHERN WI LATE TONIGHT, IT
WILL EXIT SOUTHEAST WI AROUND 8 OR 9 AM FRIDAY. DAMAGING WINDS
WOULD BE THE MAIN THREAT, BUT WE CANNOT RULE OUT HAIL OR AN
ISOLATED TORNADO. HOWEVER, THE STORM MOTION WILL SLOW DOWN
TOWARD MORNING. WITH PRECIPITABLE WATER VALUES OF NEARLY TWO
INCHES AND THE POTENTIAL FOR TRAINING STORMS, HEAVY RAIN AND
FLASH FLOODING WILL BECOME A LARGER CONCERN.
IF THE LINE MISSES US, THEN A STALLED OUTFLOW BOUNDARY WILL BE
ONE TO WATCH FOR ADDITIONAL CONVECTIVE DEVELOPMENT FRIDAY
AFTERNOON (WHICH THE HRRR IS SHOWING). TIMING OF
AFTERNOON/EVENING CONVECTION FRIDAY IS HIGHLY DEPENDENT UPON HOW
QUICKLY THE MORNING STORMS AND CLOUDS CLEAR. IF THERE IS AMPLE
TIME WITH SUNNY SKIES, THEN THERE IS A HIGHER RISK FOR A FEW
STRONG/SEVERE STORMS. AGAIN, DAMAGING WINDS WOULD BE THE MAIN
THREAT WITH HAIL AND TORNADO A MORE ISOLATED THREAT.
CRONCE
LONG TERM
ISSUED 326 PM CDT THU SEP 3 2026
SATURDAY THROUGH THURSDAY:
THE STALLED FRONTAL BOUNDARY IS EXPECTED TO GET PUSHED TO THE
SOUTHWEST OF WISCONSIN ON SATURDAY AS THE UPPER RIDGE LIFTS INTO
MN AND A MORE AMPLIFIED TROUGH DEVELOPS OVER THE EASTERN GREAT
LAKES. THE FRONTAL BOUNDARY MAY TRIGGER A FEW SHOWERS AND STORMS
(SIMILAR LOCATION AS A LAKE BREEZE) MIDDAY THROUGH EVENING
SATURDAY SO WE ARE CARRYING CHANCE POPS.
WITH NORTHEAST TO EASTERLY WINDS ACROSS ALL OF SOUTHERN WI ON
SUNDAY AND THE FRONTAL BOUNDARY SHUNTED TO OUR WEST, WE HAVE A
DRY FORECAST ON SUNDAY AND MONDAY. HIGHS WILL BE MUCH LOWER
THAN PREVIOUS DAYS, RANGING FROM THE UPPER 70S EAST TO THE LOWER
80S WEST ON THIS HOLIDAY WEEKEND.
OUR PRECIP CHANCES WILL RETURN TO SOUTHERN WI TUESDAY AS THE
WARM AND HUMID AIR RETURNS DUE TO LOW PRESSURE TRACKING FROM THE
NORTHERN PLAINS INTO ONTARIO. THIS WILL BE ANOTHER SITUATION
WHERE A FRONTAL BOUNDARY COULD STALL OVER SOUTHERN WI AND BE THE
FOCUS FOR CONTINUOUS CHANCES FOR SHOWERS/STORMS THROUGH THE
REST OF THE WORK WEEK.
CRONCE
AVIATION
ISSUED 713 PM CDT THU SEP 3 2026
VFR SHOULD PERSIST THROUGH THE EVENING, THOUGH SOME LAKESHORE
TERMINALS MAY SEE SOME MARINE FOG ADVECT INLAND AROUND 06Z IN
AFTERWARD, INTRODUCING SOME VIS RESTRICTIONS. THUNDERSTORMS ARE
EXPECTED TO START AS EARLY AS 06Z IN EAST CENTRAL WI WITH THEIR
NUMBER/COVERAGE BECOMING MORE WIDESPREAD TOWARD DAYBREAK ON
FRIDAY. CEILINGS WITH CONVECTION ARE EXPECTED TO BE BETWEEN 1500
TO 3000 FEET. AREAS OVER SOUTHWEST WISCONSIN MAY MISS OUT ON THE
LIONS SHARE OF THE THUNDERSTORMS ACTIVITY AND STAY IN VFR.
CMILLER
MARINE
ISSUED 326 PM CDT THU SEP 3 2026
A FRONTAL BOUNDARY WILL REMAIN ACROSS THE GREAT LAKES REGION
THROUGH FRIDAY. AS THIS FRONTAL BOUNDARY WAFFLES NORTH TO SOUTH
ACROSS THE LAKE FROM DAY TO DAY, GENERALLY EAST TO NORTHEAST WINDS
ARE EXPECTED NORTH OF THE FRONT, WITH EAST TO SOUTHEAST WINDS
SOUTH OF THE FRONT. ON AND OFF THUNDERSTORMS WILL BE POSSIBLE
ALONG AND NORTH OF THIS FRONTAL BOUNDARY THROUGH AT LEAST FRIDAY
NIGHT. THEN HIGH PRESSURE AROUND 30.1 INCHES BUILDS OVER HUDSON
BAY ON SATURDAY, WHILE LOW PRESSURE AROUND 29.6 INCHES MOVES INTO
THE NORTHERN GREAT PLAINS. SIMILAR TO EARLIER WEEK STORMS,
WIDESPREAD SEVERE WEATHER IS NOT ANTICIPATED, THOUGH ISOLATED
STRONGER STORMS WITH HAIL AND GUSTY WINDS ARE POSSIBLE.
CRONCE
MKX WATCHES/WARNINGS/ADVISORIES
WI...NONE.
LM...NONE.
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