Area Forecast Discussion

KEY MESSAGES

- Widespread showers and a few thunderstorms will continue into tonight. Additional rainfall up to 1 inch will be possible south of Highway 29, but the threat for widespread flooding has diminished as the heaviest rainfall remains anchored further south.

- A Beach Hazards Statement and Small Craft Advisory have been issued into this evening for areas south of Algoma. Additional advisories are also in effect Sunday morning through Tuesday as strong northeast winds and high waves develop.

- A quieter and drier weather pattern will settle into the region early to mid next week. Patchy frost will be possible at times across the northwoods.

DISCUSSION

Issued at 126 PM CDT Sat Sep 19 2026

Rest of Today/Tonight: Showers will gradually expand in coverage this afternoon as a surface low and the right rear quadrant of a jet streak pass over the region. A few embedded thunderstorms are possible as well this afternoon, mainly across central WI as southerly flow south of stalled warm front bring weak elevated instability to those areas. As the low exits the region tonight showers will come to an end from north to south with a surge of much drier air moving into the region.

Quiet weather returns for next week: For the long term period from Sunday through Friday, a prolonged stretch of quiet and dry weather is anticipated across north-central and northeast Wisconsin. Shortwave energy originating from a western trough will slowly migrate across the central Plains and southern Great Lakes toward the East Coast during the week, keeping deep moisture and rain chances suppressed well south of the local area. Strong high pressure centered over northern Ontario and Quebec will maintain an expansive plume of dry air across northern Wisconsin, keeping rain probabilities below 10 percent through Saturday. Under clear to partly cloudy skies, efficient radiational cooling on Monday and Tuesday nights will drop overnight low temperatures into the mid to upper 30s across north-central Wisconsin, leading to patchy frost formation in low-lying areas. A steady warming trend will take place throughout the week as afternoon high temperatures rise from the low and mid 60s on Monday and Tuesday into the low and mid 70s by Friday.

AVIATION

for 18Z TAF Issuance Issued at 1207 PM CDT Sat Sep 19 2026

Poor flying conditions expected for the rest of the day as low pressure moves across the region, bringing widespread IFR to LIFR ceilings, IFR and MVFR visibilities, and periods of rain and drizzle. There is a 20% chance of thunderstorms this afternoon mainly south of Hwy 29, but confidence is sufficiently low to exclude from the forecast.

As low level winds shift to the northeast, improving flight conditions are expected to return from northwest to southeast overnight. A return to VFR/MVFR is plausible at all TAF sites, starting with RHI around 03-05Z and reaching MTW by 09-11Z.

East/southeast winds will be rather steady today, then will shift to the northeast between 22-02Z. Gusts to 20 kts are expected at times.

MARINE

Issued at 126 PM CDT Sat Sep 19 2026

Gusty southeast winds up to 25 knots ahead of the low will build waves to 3 to 6 feet along the Lake Michigan shoreline south of Algoma through this evening. Small Craft Advisory and Beach Hazards Statement remain in effect through 10 PM. Following a brief lull in winds and waves late tonight, northeast winds will increase to 15 to 25 knots early Sunday morning following the passage of the surface low. These strong northeast winds will persist into Tuesday as a high-pressure system builds across northern Ontario and Quebec, resulting in building waves of 4 to 8 feet and a high risk of dangerous rip currents along the Lake Michigan coast. A second Small Craft Advisory and Beach Hazards Statement have been issued beginning at 6 AM Sunday and will remain in effect through Monday and much of Tuesday.

GRB WATCHES / WARNINGS / ADVISORIES

Beach Hazards Statement from Sunday morning through Monday afternoon for WIZ022.

Beach Hazards Statement until 10 PM CDT this evening for WIZ040- 050.

Beach Hazards Statement from Sunday morning through Tuesday evening for WIZ040-050.