textproduct: Milwaukee/Sullivan

KEY MESSAGES

- Scattered showers and thunderstorms with hail up to one inch diameter and localized gusty winds to 45mph will end from west to east late this afternoon.

- Widespread showers (80-90 percent chance) and scattered thunderstorms Wednesday and Wednesday night. Still monitoring a conditional risk for severe storms (hail/wind), though the greatest chances will be to the south of the area.

- Locally heavy rain Wednesday into Wednesday night is targeting far southern Wisconsin near the WI/IL state line. - Winds and waves may approach Small Craft Advisory criteria Wednesday afternoon into Thursday.

SHORT TERM

Issued 148 PM CDT Tue Jun 16 2026

Rest of This Afternoon through Wednesday night:

Scattered showers and storms have blossomed within a broad area of cyclonic flow associated with an upper low moving into WI. Thus far the greatest coverage of storms has been along/north of I-94, with a few in far southeastern portions of the state. Lightning, hail up to one inch diameter and wind gusts to 45mph will continue this afternoon, with this activity tapering off from west to east during the late afternoon/early evening.

Quiet weather is expected tonight with lows in the 50s.

Our next storm system will be on our western doorstep first thing Wednesday morning. Broad area of rain and embedded thunder is expected for the morning hours. Severe storms are not expected during this timeframe.

Looking at the parameter spacing for tomorrow afternoon and evening, the corridor of greatest shear and instability will be shunted to our south. Much like last Thursday's event, we are just on the outside looking to the south for the better environment. That said, there is an opportunity for some recovery just ahead of the surface low entering central WI during the mid/late afternoon hours. This recovery may make it into western/southwestern portions of the area, and we will need to watch this very closely. This will be another situation of watching the mesoscale changes very closely. If instability recovery occurs ahead of the surface low, MLCAPE will approach 1500 J/kg and enough speed shear to support damaging winds and hail with a few storms.

Gagan

LONG TERM

Issued 148 PM CDT Tue Jun 16 2026

Thursday through Tuesday:

As the low pressure moves out of the region by early Thursday morning, precip chances will diminish with precipitable water dropping below 1 inch. Lingering scattered showers are possible during the day Thursday, trending dry Thursday evening. High pressure will move in from the northern part of the Great Plains. With this, cooler and drier air will be expected ahead of the weekend. By the beginning of the weekend, warmer temps and increased moisture will be advected into the region as mid- level flow becomes more southerly.

The next chance for precipitation will be on Sunday, when a low pressure system moves westward from the Central Plains into southern Wisconsin. With this, precipitable water will increase to be around 1.5 inches along the WI/IL border and this will be the region with precip chances will be the greatest (~50-60%). By Monday morning, the low pressure system will move out of the areas and another round of high pressure from the Dakotas will start to build in by Monday afternoon/evening.

Soergel/Gagan

Gagan

AVIATION

Issued 148 PM CDT Tue Jun 16 2026

Active weather pattern over the next 24 to 36 hours. Scattered showers and thunderstorms will move west to east across southern Wisconsin this afternoon, exiting prior to sunset. Lightning, hail (mostly under one inch), and wind gusts to 45mph are expected with this activity. Overall, ceiling and visibility restrictions will be limited and rather brief. Short periods of IFR visibility and MVFR ceilings are expected beneath the cores of these storms.

These showers and storms will exit/decrease in coverage by late afternoon and early this evening with gusty westerly winds decreasing in the evening.

Another round of rain and embedded storms will move in from the west Wednesday morning. A larger coverage of rainfall is expected with VFR ceilings and gradually lowering to MVFR late late morning. Winds will shift to the southeast during the daylight hours of Thursday morning.

Gagan

MARINE

Issued 148 PM CDT Tue Jun 16 2026

Breezy southerly winds will shift to the west-southwest this afternoon into this evening as a low pressure system deepens over northern Lake Michigan (29.5 inches). Scattered to numerous showers and thunderstorms are expected across the lake throughout today. A couple of stronger cells this afternoon will produce hail up to the size of one inch.

A weak surface ridge will cross the lake tonight, with westerly winds subsiding. A stronger low pressure system (29.2 inches) will then track eastward from around South Dakota, crossing Lake Michigan Wednesday evening. Ahead of the low, expect gusty southeast winds Wednesday morning and afternoon (particularly over the southern half of the lake) with increasing chances for thunderstorms, some of which could be strong (particularly over far southern portions of the lake). Breezy west to northwest winds are expected Wednesday night into Thursday as the low exits east.

Gagan

MKX WATCHES/WARNINGS/ADVISORIES

WI...None. LM...None.