textproduct: Milwaukee/Sullivan

KEY MESSAGES

- Isolated to scattered showers (20 to 50 percent) should shift east across the area into this evening, perhaps lingering overnight in the east before exiting. An isolated thunderstorms may occur this evening.

- Some fog and low stratus clouds should develop and shift onshore in the areas near Lake Michigan by later this evening into Sunday morning. Not expecting dense fog at this time, but will monitor trends.

- Some fog is also expected over Lake Michigan during this time, and may linger into Sunday and Sunday night. Will monitor trends for dense fog potential.

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

UPDATE

Issued 714 PM CDT Sat May 23 2026

A weak cold front/convergence boundary should continue to shift east through the area this evening and overnight. There is some weak differential CVA aloft pushing into the area as well, with some low level moisture and weak instability. Isolated to perhaps scattered showers (20 to 50 percent) should shift east across the area this evening with the boundary. This may linger into the overnight hours in the east before exiting. An isolated thunderstorm may occur as well into this evening, with the weak instability.

Light onshore winds into tonight should allow for low status clouds and fog to push onshore in the areas near Lake Michigan, lingering into Sunday morning before pushing back offshore. Not expecting dense fog at this time, though will continue to monitor trends and see if lower visibility develops. There may be patchy fog further inland as well overnight into early Sunday morning.

Clouds should gradually push east of the area by midday Sunday, with a dry and pleasant day expected in the afternoon. Light to modest west winds are expected inland, with a southeast lake breeze developing in the afternoon near the lake. Highs Sunday should warm into the upper 70s over most inland areas, with temperatures turning cooler near the lake in the afternoon.

Wood

SHORT TERM

Issued 138 PM CDT Sat May 23 2026

This afternoon into Sunday Night:

The main focus through tomorrow is on the chances for rain showers/isolated thunderstorms this afternoon into tonight followed by some borderline fire weather conditions on Sunday.

For this afternoon into tonight, watching a narrow corridor of convergence/forcing/moisture that will propagate eastward and bring a 2-4 hour window of rain showers along with it across southern Wisconsin. Meso guidance has been fairly consistent with the timing and environment as this comes through SW WI around 21-02z and through SE WI between 2-8z. SBCAPE of about 300-500 J/kg develops along this narrow corridor with the RAP/NAM/GFS soundings all showing this unstable layer being between 850-650mb or 0 to +10C. Mid level temps are fairly warm, so am doubtful that we'll see much in the way of lightning activity with this despite the instability as any ice formation would be minimal. Regardless, will be watching the window as this moves through into tonight.

Depending on how fast this band moves through, there could be some patchy radiation fog that develops tomorrow morning as winds will be light to calm, dew point spread minimal and possibly some fresh rain from these showers moving through. IF the fog does form, it will quickly dissipate by mid morning due to the warmer and drier air advecting in on the northern periphery of the surface ridge. Going through the rest of Sunday, skies should be clear/sunny with deep mixing likely by the late morning hours. Winds will increase to potentially gust up to around 20kts when peak mixing occurs which should also drop the dew points/RHs a bit. With temperatures getting into the 70s, will have to watch the trends for mixing and if we have some borderline fire weather concerns. Fuels don't appear to be there/an issue though with green up complete.

Halbach

LONG TERM

Issued 138 PM CDT Sat May 23 2026

Monday through Saturday:

A warmer pattern looks to setup for much of next week as the low/mid level flow becomes more southwesterly with 850mb temps getting to around +15C by Monday and staying there through much of the week. There's some uncertainty going into the later part of next week as the 23.12z GFS and GEM retrogrades an upper level low back south across New England which puts the Great Lakes region into the backside, NE cold air advection area of the low. However, the 23.00z Euro doesn't show this occurring and keeps us in the warmth.

Not much in the way for any rain expected over this period as much of the long term guidance shows surface ridging over much of the Great Lakes region. IF the 23.12z GFS scenario pans out, there could be a chance when the cold front/CAA kicks in on Tuesday night/Wednesday.

Halbach

AVIATION

Issued 714 PM CDT Sat May 23 2026

A weak cold front/convergence boundary should continue to shift east through the area this evening and overnight. Isolated to perhaps scattered showers (20 to 50 percent) should shift east across the area this evening with the boundary. This may linger into the overnight hours at the eastern terminals before exiting. An isolated thunderstorm may occur as well into this evening, with the weak instability.

Light onshore winds into tonight should allow for low status clouds down to 800 to 1200 feet AGL and fog of 1 to 4 miles to push onshore in the areas near Lake Michigan, lingering into Sunday morning before pushing back offshore. Not expecting dense fog at this time, though will continue to monitor trends and see if lower visibility develops. There may be patchy fog of 3 to 5 miles further inland as well overnight into early Sunday morning.

Clouds should gradually push east of the area by midday Sunday, with a dry and pleasant day expected in the afternoon. Light to modest west winds are expected inland, with a southeast lake breeze developing in the afternoon for terminals near the lake.

Wood

MARINE

Issued 714 PM CDT Sat May 23 2026

Low pressure around 29.9 inches currently entering the western portion of Lake Erie has left a weak wind field in its wake as it tracks to the east toward New England. Another area of low pressure around 29.8 inches, currently over far southeast Manitoba, will track eastward across Ontario tonight into Sunday and pull a weak cold front eastward along with it. This front should reach eastern Lake Michigan early Sunday morning and exit by late morning.

Some fog is expected to develop across the lake by later this evening and linger overnight into Sunday morning. Will monitor trends for dense fog development. It may linger further into Sunday and Sunday night, as milder air moves over and remains over the cooler lake waters.

Going into early next week, a broad ridge of high pressure around 30.2 inches is expected to set up over the eastern Great Lakes, ushering in more southwesterly winds across Lake Michigan. Some questions remain for later in the week with whether a cold front drops down from the north by midweek.

Halbach/Wood

MKX WATCHES/WARNINGS/ADVISORIES

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