textproduct: Milwaukee/Sullivan

KEY MESSAGES

- Scattered light sprinkles or showers will continue to shift southeast through the area until early this evening.

- Frost is expected overnight into early Monday morning, with low temperatures in the middle to upper 20s. Those with sensitive plants should cover them tonight. - Temperatures rise well above normal Tuesday through Thursday.

- Next chances (40 to 60 percent) for showers and thunderstorms Thursday night.

SHORT TERM

Issued 159 PM CDT Sun Apr 19 2026

Tonight and Monday:

Scattered sprinkles/flurries or light rain/snow showers will continue to shift southeast through the area until early this evening. No snow accumulations are expected. They are being driven by continued differential CVA from a passing 500 mb vorticity maximum, as well as fairly robust low to mid-level frontogenesis response. This activity should linger through peak heating this afternoon, before weakening by early evening.

Otherwise, scattered to broken clouds should linger until early this evening. Gusty northwest winds into early evening should also weaken tonight, as high pressure moves southeast into the region. Skies should gradually clear out this evening, with mostly clear skies overnight into early Monday morning.

The light winds and clearing skies should allow for lows to drop into the middle to upper 20s over most of the area. This should allow for frost to develop. Those with sensitive plants should cover them tonight.

Dry conditions are expected Monday, as the high shifts to the southeast of the area. Some diurnal stratocumulus clouds or mid-level clouds may develop and move through the area. Some lake effect clouds may also shift southwest toward the lakeshore areas in the afternoon.

Light south southwest winds are expected inland, with a southeast lake breeze in the afternoon near Lake Michigan. Highs should rise into the lower to middle 50s inland, with weak warm air advection, and 40s closer to the lake.

Wood

LONG TERM

Issued 159 PM CDT Sun Apr 19 2026

Monday night through Sunday:

500 mb cluster analysis continues to show an anomalous ridge axis developing over the Great Lakes region Tuesday into Thursday, before an anomalous trough shifts east into the region by the weekend and elongates over a good portion of the north central part of the country.

This setup should allow for generally south to southwest winds and warm air advection to develop and continue Tuesday into Thursday across the area, which should result in a warming trend toward well above normal temperatures Tuesday into Thursday.

One caveat will be a backdoor cold front that shifts south southwest across Lake Michigan later Tuesday afternoon and evening. This will bring a sharp drop in temperatures near the lake later on Tuesday, then across the rest of the area into Tuesday evening. Onshore winds Wednesday should keep lakeshore areas much cooler than the lower to middle 70s well inland. Thursday should bring south southwest winds over most of the area, with highs well into the 70s. Lakeshore areas may see south southeast winds and some cooler temperatures there.

Ensemble means suggest the cold front should move east through the area Thursday night and exit by midday Friday. This will bring the next chances (50 to 80 percent) for showers and thunderstorms. Will have to watch for some stronger storm potential, though the frontal timing is not ideal and the best chances for this may be southwest of Wisconsin. The front looks fairly progressive, so may have a relatively low heavy rain risk.

Kept the rest of the forecast as is for now, which looks to be somewhat cooler, but still mild, with small (around 20 percent) chances for showers at times.

Wood

AVIATION

Issued 159 PM CDT Sun Apr 19 2026

Scattered sprinkles/flurries or light rain/snow showers will continue to shift southeast through the area until early this evening. No snow accumulations are expected. Otherwise, scattered to broken clouds with ceilings around 5000 to 7000 feet AGL should linger until early this evening.

Gusty northwest winds into early evening should also weaken tonight, as high pressure moves southeast into the region. Skies should gradually clear out this evening, with mostly clear skies overnight into early Monday morning.

Dry conditions are expected Monday, as the high shifts to the southeast of the area. Scattered to broken clouds with ceilings around 5000 to 7000 feet AGL may develop and move through the area late morning and afternoon. Some lake effect clouds with ceilings of 2000 to 2500 feet AGL may also shift southwest toward the lakeshore terminals in the afternoon and evening.

Light south southwest winds are expected inland Monday, with a southeast lake breeze in the afternoon for terminals near Lake Michigan.

Wood

MARINE

Issued 159 PM CDT Sun Apr 19 2026

A few northwest gusts to 25 knots may occur into early evening for the nearshore waters of Lake Michigan, but not frequent enough for a Small Craft Advisory.

High pressure around 30.4 inches is expected to shift southeast across the region tonight into Monday morning, then shift southeast in the afternoon. Gusty north to northwest winds are expected into early evening, before weakening tonight into Monday.

Increasing south winds are expected later Monday afternoon into Monday night, as the high moves further southeast of the region. A few gales may occur Monday night into early Tuesday morning, particularly over the northern third of the lake.

Winds and waves may reach Small Craft Advisory levels at times later Monday into early Tuesday, mainly north of Port Washington.

A backdoor cold front should then move southward across Lake Michigan Tuesday afternoon and evening, shifting winds to the northeast behind it. High pressure around 30.4 inches to the northeast of the region Wednesday should bring lighter winds to the area.

Winds should become southeast to south and increase later in the week, as strong low pressure around 29.2 inches develops in the northern Plains. Winds and waves may reach Small Craft Advisory levels at times in the nearshore waters during this period.

Wood

MKX WATCHES/WARNINGS/ADVISORIES

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