textproduct: Milwaukee/Sullivan

KEY MESSAGES

- Expect a gradual warming trend through early next week with highs in the 80s by Memorial Day.

- 40-50% percent chances for showers late this afternoon over south central WI, slowly spreading east across S WI through the night. Isolated thunderstorms are possible.

UPDATE

Issued 900 AM CDT Sat May 23 2026

Quick update to the rain chances this morning as a band of showers has developed in SW to NW WI along what appears to be the leading edge of 850mb moisture advection. These showers may be short lived, but likely hitting the ground as cloud bases are around 4-6kft. No lightning expected from this band of rain showers as instability is lacking and so far reflectivity at -10C has peaked at 20dBZ and quickly decreased.

Another north to south band of rain showers and possibly thunderstorms appears set to come into SW WI around 3-4pmish before slowly dragging eastward to the Lake Michigan shoreline around midnight or shortly after. Some lightning looks possible, but most of the instability is in the 0 to +10C range with an inversion around 0C. So, some showers could hit, but lightning would be isolated at best based on the RAP and other mesomodels.

Halbach

SHORT TERM

Issued 1058 PM CDT Fri May 22 2026

Tonight through Sunday:

Surface low pressure will approach the area from the southwest tonight, passing by to the southeast on Saturday. Models have continued to trend drier for southern Wisconsin with this system, with maybe a little light rain or sprinkles brushing the southeast later tonight into early Saturday. Clouds will hang around yet another day on Saturday as the low moves through the region and a shortwave approaches from the west. Trended the forecast towards the cooler end of model guidance for highs Sat given the clouds, though temps should still return to around normal values for late May away from Lake Michigan. Onshore winds will keep it a bit cooler near the lake.

Kept a chance for showers and a few rumbles of thunder late this afternoon into tonight as the shortwave slowly slides through the area. Upstream showers/storms this evening along with higher dewpoints over Iowa are boosting confidence a bit in the shower/storm chances later tomorrow.

Skies are expected to clear west to east on Sunday, with above normal temps likely under a good amount of sunshine in the afternoon.

A high swim risk continues into late tonight for all southern Wisconsin lakeshore counties. Life threatening waves and currents are expected.

DDV

LONG TERM

Issued 1058 PM CDT Fri May 22 2026

Monday through Friday:

Monday looks mainly dry under surface high pressure and as upper level riding begins to build in from the west. There's a small chance though that an area of showers/storms comes through the top of the ridge on Monday, but confidence in this scenario is decreasing. Above normal temps are expected for Memorial Day along with somewhat higher dewpoints as well.

Warm temps and higher dewpoints will persist into mid-week, with some instability suggesting the potential for more shower/storm chances if a wave or two pushes through the area. It then looks cooler and drier late week as surface high pressure builds in from the north.

DDV

AVIATION

Issued 541 AM CDT Sat May 23 2026

MVFR Cigs over ern WI this morning becoming scattered this afternoon. Scattered showers and isolated thunderstorms will then slowly move into south central WI late this afternoon, then slowly east through the night. Areas to widespread MVFR Cigs are expected to redevelop from late this evening through Sunday morning. Patchy light fog is also possible.

Gehring

MARINE

Issued 541 AM CDT Sat May 23 2026

High pressure around 30.5 inches centered over Quebec will slowly move across the New England coast later today and tonight. Meanwhile, low pressure of 29.8 inches over the western Ohio Valley will move to Lake Huron and southern Ontario for tonight. Modest to breezy easterly winds will continue into this evening over far northern Lake Michigan. Elsewhere, light to modest east northeast winds will turn northerly for this afternoon. The light winds will then gradually turn southerly late tonight into Sunday morning across all of Lake Michigan. Light to modest southerly winds are then likely for Sunday through Tuesday.

Gehring

MKX WATCHES/WARNINGS/ADVISORIES

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