240
FXUS63 KMKX 170421
AFDMKX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI
1121 PM CDT WED SEP 16 2026
KEY MESSAGES
- AREAS OF SHOWERS & ISOLATED THUNDER LATER TONIGHT INTO
THURSDAY MORNING. BRIEF HEAVY DOWNPOURS ARE POSSIBLE SOUTH OF
A KENOSHA- MADISON-LONE ROCK LINE.
- PROLONGED PERIOD OF MODERATE TO HIGH SWIMMING RISK CONDITIONS EXPECTED
FRIDAY EVENING INTO EARLY NEXT WEEK.
- PERIODS OF WIDESPREAD SHOWERS & STORMS EXPECTED FRIDAY EVENING THROUGH
SATURDAY. LOCALLY HEAVY RAINFALL AND FLOODING IMPACTS ARE
POSSIBLE.
- OFF & ON LIGHTER RAIN SUNDAY INTO EARLY NEXT WEEK. CONDITIONS
DRY OUT BY MID-WEEK.
SHORT TERM
ISSUED 1130 PM CDT WED SEP 16 2026
CURRENT OVERNIGHT THROUGH FRIDAY:
SYNOPSIS/MESOANALYSIS: SURFACE ANALYSIS PLACES A WAVY STATIONARY
FRONT ALONG A KANSAS CITY - SPRINGFIELD, ILLINOIS - INDIANAPOLIS
LINE LATE THIS EVENING. WARM ADVECTION ROOTED WITHIN THE 925-700 MB
LAYER IS ONGOING NORTH OF THE BOUNDARY, AND IS RESPONSIBLE FOR THE
SCATTERED SHOWERS ONGOING FROM NORTH-CENTRAL IOWA TO NORTHWEST
INDIANA. A BROADER AREA OF STEADIER RAINS IS ONGOING FROM NORTHWEST
WISCONSIN INTO EAST-CENTRAL MINNESOTA AHEAD OF AN UPPER DISTURBANCE
MOVING IN FROM THE NORTHERN PLAINS. THE AFOREMENTIONED FORCING
MECHANISMS---SPECIFICALLY THE LIFT FROM THE APPROACHING NORTHERN
PLAINS DISTURBANCE & THE INCREASING WARM ADVECTION NORTH OF THE
STATIONARY FRONT---WILL WORK TOGETHER TO SUPPORT SCATTERED SHOWERS
ACROSS SOUTHERN WISCONSIN FROM THE SECOND HALF OF THE OVERNIGHT INTO
THURSDAY MORNING. BRIEF HEAVY DOWNPOURS MAY ACCOMPANY SHOWERS IN FAR
SOUTH-CENTRAL & SOUTHWEST WISCONSIN, WITH HAZARDS OTHERWISE
UNEXPECTED. HIGH PRESSURE WILL BUILD INTO NORTHERN WISCONSIN DURING
THE SECOND HALF OF THE DAY THURSDAY, SUPPORTING DRY CONDITIONS FROM
THE AFTERNOON THROUGH THE OVERNIGHT. CURRENTLY CLOSING IN ON THE
FOUR CORNERS, AN UPPER DISTURBANCE WILL QUICKLY ADVANCE INTO THE
NORTHERN PLAINS THURSDAY NIGHT, ENCOURAGING CYCLOGENESIS AT THE
SURFACE. THE NEWLY-FORMED SURFACE LOW WILL PROGRESS INTO THE
MISSOURI VALLEY ON FRIDAY. INCREASING WARM ADVECTION AHEAD OF THE
LOW COULD SUPPORT SCATTERED SHOWERS & STORMS FRIDAY AFTERNOON, WITH
MORE WIDESPREAD PRECIP EXPECTED TO HOLD OFF UNTIL THE OVERNIGHT
HOURS.
REST OF OVERNIGHT INTO THURSDAY MORNING: EXPECTING SCATTERED SHOWERS
TO GRADUALLY FILL IN AREAWIDE AS LARGE SCALE ASCENT INCREASES
REGIONALLY. LACK OF INSTABILITY WILL KEEP EMBEDDED THUNDERSTORMS TO
A MINIMUM, WHICH WILL IN TURN KEEP RAINFALL RATES ON THE LIGHT-
MODERATE SIDE WITH NO HYDRO IMPACTS. EXPECT THAT ANY EMBEDDED
CONVECTION WILL REMAIN CONFINED TO FAR SOUTH-CENTRAL & SOUTHWEST
WISCONSIN, WHERE THE NORTHERN EDGE OF THE LOW LEVEL JET COULD ADVECT
MARGINAL (~400 J/KG OR LESS) INSTABILITY VALUES NORTHWARD. ANY
EMBEDDED THUNDERSTORMS FORMING OVER THIS PART OF THE AREA COULD
PRODUCE BRIEF HEAVY DOWNPOURS, WITH WIDELY SCATTERED COVERAGE &
PROGRESSIVE STORM MOTIONS KEEPING HYDRO CONCERNS LOW. THUS THINKING
THAT ANY MORE ORGANIZED HEAVY RAINFALL/HYDRO THREAT WILL REMAIN
SOUTH OF THE STATE LINE THROUGH EARLY THURSDAY MORNING, WHERE THE
CORE OF THE LOW LEVEL JET WILL REMAIN CENTERED & HIGHER INSTABILITY
WILL FOCUS.
FRIDAY: CAN'T RULE OUT SOME SCATTERED SHOWERS/STORMS DURING THE
AFTERNOON ACROSS THE WEST AS BROAD WARM ADVECTION INCREASES AHEAD OF
LOW PRESSURE IN THE MISSOURI VALLEY. THINKING ANY ACTIVITY WILL STAY
CONFINED TO THE WESTERN HALF OF THE AREA, WITH RESIDUAL HIGH
PRESSURE INFLUENCES LINGERING FURTHER EAST. NOT CURRENTLY EXPECTING
HAZARDS IN ANY SCATTERED STORMS GIVEN LOWER INSTABILITY & DEEPER
MOISTURE STILL SOUTHWEST OF THE AREA.
QUIGLEY
LONG TERM
ISSUED 1130 PM CDT WED SEP 16 2026
FRIDAY NIGHT THROUGH WEDNESDAY:
SYNOPSIS: LOW PRESSURE WILL SLOWLY CONTINUE EAST INTO THE UPPER
MISSISSIPPI VALLEY FRIDAY NIGHT, WITH DEEPENING WARM ADVECTION & LOW
LEVEL JET DYNAMICS SUPPORTING WIDESPREAD AREAS OF SHOWER AND
THUNDERSTORM DEVELOPMENT. AN UNSEASONABLY MOIST ENVIRONMENT WILL
SUPPORT HEAVY DOWNPOURS IN ANY THUNDERSTORMS, WITH LOCALLY HEAVY
RAINFALL POSSIBLE. THE LOW WILL CONTINUE EAST TOWARD SOUTHERN
WISCONSIN DURING THE DAY SATURDAY, SLOWLY PULLING A TRAILING COLD
FRONT THROUGH THE REGION DURING THE AFTERNOON AND EVENING HOURS.
ADDITIONAL SHOWER/STORMS & HEAVY DOWNPOUR POTENTIAL MAY ACCOMPANY
THE PASSING FRONT, THOUGH LOCATIONS & COVERAGE OF DEVELOPMENT WILL
DEPEND ON FRONTAL POSITIONING AND & THERMODYNAMIC RECOVERIES
OCCURRING IN THE WAKE OF EARLIER DAY PRECIP. SEVERE WEATHER
POTENTIAL CURRENTLY APPEARS LOW IN ANY STORMS OCCURRING FRIDAY NIGHT
THROUGH SATURDAY EVENING, THOUGH TRENDS WILL CONTINUE TO BE
MONITORED FOR ISOLATED STRONGER STORMS WITH GUSTY WINDS IN COMING
UPDATES. HIGH PRESSURE WILL BUILD INTO ONTARIO SATURDAY NIGHT INTO
SUNDAY, SHOVING THE COLD FRONT SOUTH OF THE AREA. AN UPPER
DISTURBANCE WILL MOVE IN FROM THE NORTHERN PLAINS ON MONDAY,
BRINGING ADDITIONAL CHANCES FOR NON-IMPACTFUL RAIN SHOWERS.
CONDITIONS WILL DRY OUT BY MID-WEEK.
FRIDAY NIGHT THROUGH SATURDAY MORNING: WIDESPREAD SHOWERS AND STORMS
WILL OVERSPREAD THE AREA AS A STRENGTHENING LOW LEVEL JET ALLOWS
WARM/MOIST ADVECTION TO BLOSSOM REGIONALLY. APART FROM MAINTAINING
SHOWER & STORM DEVELOPMENT, THE WARM/MOIST ADVECTION WILL TRANSPORT
UNSEASONABLY MOIST AIR WITH PRECIPITABLE WATER VALUES ON THE ORDER
OF 1.7"+ INTO SOUTHERN WISCONSIN, SUPPORTING ENHANCED RAINFALL RATES
IN ANY THUNDERSTORMS. PRESENCE OF THIS AIR MASS & ANTICIPATED
WIDESPREAD STORM COVERAGE THUS MAKES THIS PART OF THE PERIOD ONE TO
WATCH FOR LOCALLY HEAVY RAINFALL AND POSSIBLE HYDROLOGIC IMPACTS
(URBAN/SMALL STREAM FLOODING, RISES ON RIVERS/STREAMS & ISOLATED
FLASH FLOODING). MODEST BUT STILL WELL-DEFINED DEEP LAYER WIND
FIELDS POINT TOWARD PROGRESSIVE STORM MOTIONS, WITH THE
MATERIALIZATION OF HYDRO IMPACTS LIKELY REQUIRING SUSTAINED PERIODS
OF TRAINING. WILL THUS BE WATCHING FOR ANY DEFINITIVE TRAINING
SIGNALS AS CAMS CONTINUE TO COME INTO RANGE OVER THE NEXT 12-24
HOURS. OVERNIGHT STORM TIMING SHOULD LIMIT ORGANIZED SEVERE WEATHER
POTENTIAL.
SATURDAY AFTERNOON & EVENING: DEPENDING ON A COMBINATION 1)
POSITIONING OF THE PASSING COLD FRONT AND 2) THE RELATIVE AMOUNTS OF
CLOUDS VERSUS SUNSHINE MATERIALIZING IN THE WAKE OF
OVERNIGHT/MORNING STORMS, AN ADDITIONAL BATCH OF SHOWER AND STORM
DEVELOPMENT IS POSSIBLE ACROSS PARTS OF THE AREA. THE AFOREMENTIONED
UNCERTAINTIES IN MESOSCALE ENVIRONMENT MAKE IT DIFFICULT TO
CONFIDENTLY PINPOINT WHERE ADDITIONAL STORM DEVELOPMENT MAY BE
FAVORED, WITH TRENDS BEING MONITORED INTO THIS WEEKEND.
ENVIRONMENTAL UNCERTAINTIES ASIDE, STILL UNSEASONABLY HIGH MOISTURE
WOULD SUPPORT ADDITIONAL HEAVY DOWNPOUR POTENTIAL IN ANY
THUNDERSTORMS.
SUNDAY THROUGH TUESDAY: WHILE THE NBM IS POPULATING WITH PRECIP
PROBABILITIES THROUGH A LARGE PORTION OF THIS TIME FRAME, SUSPECT
THAT THE BEST WINDOW FOR ADDITIONAL RAIN WILL BE DURING THE DAY ON
MONDAY WHEN A DISTURBANCE IS FORECAST TO MOVE INTO THE WESTERN GREAT
LAKES. WILL BE MONITORING FOR POSSIBLE REFINEMENTS AS THIS PORTION
OF THE PERIOD DRAWS CLOSER. NOT EXPECTING HYDRO IMPACTS GIVEN MUCH
LOWER PRECIPITABLE WATER VALUES IN THE WAKE OF THE WEEKEND FRONT.
EXPECT A DRYING TREND FROM TUESDAY ONWARD WITH CANADIAN HIGH
PRESSURE PROGGED TO BUILD INTO THE WESTERN GREAT LAKES.
QUIGLEY
AVIATION
ISSUED 1130 PM CDT WED SEP 16 2026
MVFR FLIGHT CATEGORIES ARE BEGINNING TO SPREAD NORTH THIS
EVENING, WITH FURTHER REDUCTIONS TO IFR POSSIBLE THROUGH THE
SECOND HALF OF THE OVERNIGHT. LOW CIGS WILL BE ACCOMPANIED BY
AREAS OF -SHRA AFTER MIDNIGHT. CONTINUE TO MONITOR RADAR TRENDS
FOR AMENDMENTS TO PRECIP MENTIONS. CAN'T RULE OUT ISOLATED CB
NEAR THE WISCONSIN- ILLINOIS BORDER, THOUGH CONFIDENCE IS TOO
LOW TO JUSTIFY ANY MENTIONS AT THIS TIME. WILL CONTINUE TO
MONITOR TRENDS INTO THIS EVENING. PRECIP WILL SHUT DOWN MID-LATE
THURSDAY MORNING AS HIGH PRESSURE MOVES IN FROM THE NORTHWEST,
THOUGH CIGS WILL BE SLOW TO RECOVER.
QUIGLEY
MARINE
ISSUED 1130 PM CDT WED SEP 16 2026
1030 MB HIGH PRESSURE IS CENTERED NEAR THE ONTARIO-QUEBEC BORDER
LATE THIS EVENING, AND WILL CONTINUE EAST THROUGH THE DAY TOMORROW.
PROGRESSION OF THE HIGH WILL MAINTAIN EAST-NORTHEAST WINDS ACROSS
THE OPEN WATERS THROUGH TOMORROW AFTERNOON. OCCASIONAL PERIODS OF
SHOWERS AND THUNDERSTORMS WILL CONTINUE INTO THURSDAY, WITH SEVERE
WEATHER NOT EXPECTED.
A NEW AREA OF 1030 MB HIGH PRESSURE WILL SHIFT FROM THE CANADIAN
GREAT PLAINS INTO ONTARIO THURSDAY NIGHT INTO FRIDAY MORNING,
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. SOME GUSTS COULD APPROACH GALE THRESHOLDS, PARTICULARLY
ON FRIDAY NIGHT AND SATURDAY MORNING. WHETHER BORDERLINE GALES WILL
BE WIDESPREAD ENOUGH TO WARRANT GALE WARNINGS REMAINS UNCERTAIN AT
THIS TIME, WITH TRENDS BEING MONITORED THROUGH THE END OF THE WEEK.
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 AS THE LOW SLOWLY MOVES
INTO THE OHIO RIVER VALLEY SUNDAY INTO THE BEGINNING OF NEXT WEEK.
A PROLONGED PERIOD OF SMALL CRAFT ADVISORY CONDITIONS IS EXPECTED
FRIDAY AFTERNOON THROUGH MONDAY. ANTICIPATE THAT HEADLINES WILL
BECOME NECESSARY AS THIS PORTION OF THE PERIOD DRAWS CLOSER.
CONTINUE TO MONITOR FOR ISOLATED GUSTS APPROACHING GALE FORCE DURING
THIS TIME FRAME, THOUGH ANY SUCH GUSTS ARE CURRENTLY EXPECTED TO
REMAIN ISOLATED AND BRIEF ENOUGH TO PRECLUDE THE NEED FOR GALE
WARNINGS. WILL NEVERTHELESS BE MONITORING FOR POSSIBLE CHANGES
THROUGH THE END OF THE WEEK. SHOWERS AND THUNDERSTORMS ARE LIKELY
TONIGHT & FRIDAY NIGHT INTO SATURDAY, WITH SEVERE WEATHER NOT
CURRENTLY ANTICIPATED.
QUIGLEY
MKX WATCHES/WARNINGS/ADVISORIES
WI...NONE.
LM...NONE.
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