Area Forecast Discussion

KEY MESSAGES

- Thunderstorms will bring a risk for 30 to 50 mph winds with isolated gusts to 60 mph late this afternoon and evening.

- Heavy rain will bring a potential for flash flooding over much of central WI where the ground is saturated. A Flood Watch is in effect until 10 PM. Localized flooding could occur elsewhere, especially in urban and poor drainage areas.

- Hazardous boating conditions on the bay and lake tonight into early Friday morning. High waves and dangerous currents for Lake Michigan beaches tonight into early Friday morning.

- A few stronger storms capable of gusty winds and small hail are possible Saturday afternoon along a secondary cold front.

DISCUSSION

Issued at 158 PM CDT Thu Jun 11 2026

The latest RAP analysis and satellite/radar imagery show a potent shortwave trough moving east across the northern plains early this afternoon. At the surface, low pressure is strengthening over northeast Iowa while last nights cold front remains stalled over southern Wisconsin. Along this stalled front, the first MCS of the day has dissipated across southern Wisconsin. Areas across central Wisconsin were on the northern fringes of this system, where strong winds behind the complex have developed due to a wake low feature. These winds have mostly dissipated early this afternoon. Elsewhere across the country, an unseasonably amplified pattern is setting up with a building ridge across the West Coast and an expanding central trough that will dictate regional weather into early next week.

Thunderstorm and Flood Potential This Afternoon/Evening: The surface low over Iowa is forecast to track northeast directly across southwest to northeast Wisconsin through this afternoon and evening. Strong dynamic forcing accompanies this low, driven by a potent 40-50 kt low-level jet surging ahead of the system and into east-central Wisconsin. This setup will likely trigger another round of strong thunderstorms across the region, with the most favorable timing window falling between 3 PM and 8 PM. Due to the intense wind fields just above the surface, even non-severe showers and storms will have the potential to mix down 30 to 50 mph winds. An isolated damaging wind gust remains possible, particularly within the stronger storm cores aligned with the low- level jet from central into northeast Wisconsin. However, the threat of widespread severe weather has trended further south today based on the latest CAM guidance and updraft helicity tracks. The primary forecast uncertainty lies in daytime instability, as developing east winds this afternoon are expected to suppress surface-based CAPE. If instability can advect into the area, a higher severe risk would target areas from Waushara to Calumet county, and potentially into Waupaca and Outagamie.

Heavy rainfall is the other major concern. Flash flood guidance is notably low across areas that received 2 to 4 inches of rain yesterday, where a Flood Watch remains in effect. A quick 1-2 inches of rain will cause localized flooding, and hourly rainfall rates over an inch could prompt urban flooding. Rain will linger over north- central Wisconsin through the rest of the evening before finally exiting overnight.

Friday and Weekend Outlook: Clearing will gradually occur overnight into Friday morning before convective clouds increase again in the afternoon. A cooler and drier synoptic pattern will briefly take hold behind the departing low pressure system as a broad longwave trough anchors itself from Hudson Bay into the western Great Lakes. Tightening pressure gradients will foster breezy conditions on Friday, with west wind gusts up to 30 mph likely over land. A quick shortwave will bring a renewal of showers and storms to north-central Wisconsin Friday night. Saturday stands out as the more active day of the weekend as a secondary cold front drops south across the state. Boundary layer moisture and daytime heating will allow instability to moderate to around 750-1000 J/kg by Saturday afternoon. When combined with a belt of 30-50 kts winds in the 700-500 mb layer, this environment will support a few stronger storms capable of producing gusty winds and small hail, with the highest precipitation chances focused over central and northeast Wisconsin.

Extended Trends: Behind the secondary weekend cold front, a distinct and reasonably strong cooling trend takes hold across the upper Midwest. High temperatures in the low 70s to low 80s through Saturday will fall back into the mid 60s to mid 70s from Sunday through Tuesday. The broad upper troughing pattern looks to flatten and turn more zonal toward midweek. The next appreciable chance for widespread rainfall is forecast for Tuesday into Tuesday night as a northern stream shortwave digs into the western Great Lakes, with yet another quick-moving system potentially bringing light rain by Wednesday.

AVIATION

for 00Z TAF Issuance Issued at 643 PM CDT Thu Jun 11 2026

Active weather will be in the region at the beginning of the TAF period, with showers stretching across central to north-central Wisconsin and a region of thunderstorms across portions of the Fox Valley towards the Lake Michigan shoreline. Stronger winds may mix in at times with these storms, with isolated gusts up to 30 to 40 knots at times, impacting primarily isolated areas near the Lake Michigan shoreline. Thunder has been removed for the central TAF sites, where instability will prove to meager to produce winds.

Ceilings may see some drops to MVFR or even IFR at times under the heaviest showers, but clearing is on its way on satellite from the west. Once the cold front arrives, expect clearing skies and an increase in wind gusts overnight into Friday, with periodic gusts to 20 to 25 knots.

GRB WATCHES / WARNINGS / ADVISORIES

Beach Hazards Statement through Friday morning for WIZ022-040- 050.

Flood Watch until 10 PM CDT this evening for WIZ030-031-035>037- 045.