textproduct: Milwaukee/Sullivan

KEY MESSAGES

- A Beach Hazard Statement is in effect through Saturday afternoon for a High Swim Risk at beaches in Milwaukee, Racine, and Kenosha Counties. The beaches in Sheboygan and Ozaukee Counties have a high swim risk beginning Friday afternoon.

- Expect a gradual warming trend through the Memorial Day weekend.

- Rain chances (20-40%) return Friday night into Saturday morning, mainly in southeast WI, with lower chances (20-30%) at times through the holiday weekend.

UPDATE

Issued 602 PM CDT Thu May 21 2026

Mostly cloudy conditions will persist through tonight with dry weather likely to continue. No significant updates to the short term forecast are anticipated.

DDV

SHORT TERM

Issued 222 PM CDT Thu May 21 2026

This afternoon through Saturday:

Mid level clouds are streaming across southern WI this afternoon. With very dry air below 10,000 ft, any precip falling from aloft would be sprinkles by the time it hits the ground, so falling as virga. The onshore winds with the cooler lake and just a little added moisture from the virga is causing some low clouds over southeast WI.

A broad low pressure trough setting up over the Plains and the gradually departing Great Lakes high will allow for an increasing pressure gradient over southern WI Friday. The persistent easterly winds will cause high waves of 3 to 5 feet along the lakeshore most of the period between now and Saturday afternoon. Therefore, the current Beach Hazards Statement for a High Swim Risk for Milwaukee, Racine and Kenosha Counties was extended until 4 PM Saturday. The northern two counties (Sheboygan and Ozaukee) were added into the headline starting at 4 PM Friday.

That broad upper trough will develop into two distinct surface lows on Friday; one over SD and one over far southern IL. The IL low is trending farther south and east in the latest model runs, thus we have a lower chance (25 to 40%) of light rain spreading across southeast WI late Friday night into Saturday morning.

That upper trough will push into northern WI by mid-late Saturday morning which will end our precip chance. However, there may be some lingering precip from an additional upper trough that could track into south central WI during the day Sat, but this would be light and short-lived.

Cronce

LONG TERM

Issued 222 PM CDT Thu May 21 2026

Saturday night through Thursday:

An upper trough will slowly drift across the Upper Great Lakes Saturday night through Sunday night. A weak shortwave ripple in the mid level flow may be enough to trigger a few showers. Right now, it looks like that ripple may cross southern WI late Saturday night into Sunday morning. With this being unfavorable timing for any added instability due to daytime heating, the chance for precip is low (15-30%) and lightning would not be a risk. If this timing shifts into Sunday afternoon, a few storms would be possible.

The upper low will depart Sunday night, and a weak mid level shortwave trough is expected to slide through WI on northwest flow Monday afternoon/evening (Memorial Day). This could kick off some scattered showers and perhaps a few thunderstorms. Again, no all-day washout for any outdoor holiday plans, but have a plan to get indoors if any storms approach.

Temperatures near the lake will be cooler all weekend due to the onshore wind through Saturday and then a lake breeze Sunday and Monday. Inland areas will see mid 60s Friday, around 70 on Saturday, and mid 70s-upper Sunday. Monday looks like the warmest day with highs around 80, but that could be cooler if showers/clouds arrive earlier in the day.

Southern WI will remain warm and fairly humid Tue-Thu, although shower/storm chances return for this period, mainly inland from Lake Michigan.

Cronce

AVIATION

Issued 602 PM CDT Thu May 21 2026

Mid and high level clouds will persist tonight through Friday. Dry weather is likely to persist through at least Friday evening, with low rain chances overnight Friday night. East winds 5-10 knots are likely tonight into early Friday, picking up a bit by the afternoon with gusts of 20-25 kt. Winds will remain more from the north to northeast at times near Lake Michigan through tomorrow.

DDV

MARINE

Issued 222 PM CDT Thu May 21 2026

High pressure centered over Lake Superior will will gradually shift eastward through the end of the week. Persistent east to northeast winds of 10 to 20 knots are expected through Friday, with winds becoming northerly on Saturday as low pressure over Illinois lifts northeast into southern Michigan. Winds could increase a bit Friday night into Saturday, depending on the exact track and strength of the low, though winds are likely to stay below gale force. Southerly winds are then expected to develop early next week.

A Small Craft Advisory is in effect for nearshore zones south of the North Point Light until Saturday afternoon due to persistent east-northeast winds and waves of 3 to 5 feet. By Friday morning, the Port Washington zone is added to the S.C.A. and the Sheboygan zone goes into effect late Friday afternoon. the period of highest waves will be late Friday afternoon through mid Saturday morning. It looks like the waves should diminish below criteria by late Saturday afternoon.

Cronce

MKX WATCHES/WARNINGS/ADVISORIES

WI...Beach Hazards Statement...WIZ066-WIZ071-WIZ072 until 4 PM Saturday.

Beach Hazards Statement...WIZ052-WIZ060...4 PM Friday to 4 PM Saturday.

LM...Small Craft Advisory...LMZ643...4 PM Friday to 4 PM Saturday.

Small Craft Advisory...LMZ644...7 AM Friday to 4 PM Saturday.

Small Craft Advisory...LMZ645-LMZ646 until 4 PM Saturday.