Marine Weather and Tide Forecast for Cedarburg, WI

SHORT TERM
Issued 241 PM CDT Thu Oct 8 2026

Tonight through Friday night:

We will see an increase in mid and high level clouds tonight due to an increase in 500mb moisture and 700mb frontogenesis. This is due to a strengthening upper trough over Quebec and an upper ridge over the southwest States. The area of 925 to 850mb warm air advection and frontogenesis will stem from a weak low developing in the lee of the Rockies over NE tonight. This will also be coincident with 700mb fgen and weak 500mb vorticity.
This concentrated area of deeper moisture and forcing will track across IA Friday morning and roughly along the WI/IL border Friday afternoon. This is a slight southward shift in what previous models had, so the precip chances trended downward a bit for us. Especially for central WI.

With this brief period of forcing and moisture tracking across southern WI on the nose of a strong low level jet Fri afternoon, we could see around a tenth of an inch of light rain (or less).
We could see a few lightning strikes with these showers due to some weak elevated instability, but no severe weather.

Cronce

LONG TERM
Issued 241 PM CDT Thu Oct 8 2026

Saturday through Thursday:

Expect breezy southerly winds on Saturday with gusts of 25 to 30 mph in the afternoon. The wind direction has trended a little more south than southwest, which means that areas right along the lakeshore should remain cooler due to a slight onshore component (lake- induced). Very warm temps are expected due to persistent and dry southwest flow originating from the western states. This is due to a shift from ridging over the Pacific Northwest to a broad trough and a resultant surface low over the Northern Plains, and high pressure over the northeastern States. With 925mb temps of 20 to 21C over southern WI and efficient mixing of a very dry air mass right up to that level (and likely a weak inversion above that), we can expect the high temps to be right around 80 (up to 82). The record high for that day is 84.

With the warm temps and dewpoints in the lower 50s (with potential for lower due to mixing), the min RH values will be in the mid 40 percent range. While this is not critical and we are still plenty green, fire weather is not a major concern, but also not something to be ignored.

Hurricane Isaias over the Gulf of America will track northward and then just south of the Ohio River on Sunday (slightly farther south than previous model runs). Southeast WI will likely see cloud cover from this system (but no rain), which will keep temps in the lower- mid 70s near Lake Michigan instead of upper 70s).

A northern stream mid level trough is expected to slide across US/Canadian border and Lake Superior Monday or Tuesday (could be a series of waves) and this will push a cold front down through central and eventually southern WI. Showers and perhaps a few thunderstorms will likely accompany this front, but the timing and rainfall amounts are still very uncertain.

Cooler, more seasonable temperatures will return around the middle of next week as high pressure moves over the Upper Great Lakes.The next low approaching from the Northern Plains will bring our next chance for rain to southern WI on a warm frontal boundary Wednesday afternoon and night into Thursday.

Cronce

AVIATION
Issued 241 PM CDT Thu Oct 8 2026

Expect mid and high clouds through the period. Light winds tonight will become southeast Friday morning. A period of light showers with a small chance of lightning will lift through southern WI Friday afternoon. Depending on model trends and consistency, a tempo or prob30 may be needed to cover these chances. Low level wind shear with strong south-southwest winds just above the surface is expected Friday night.

Cronce

MARINE
Issued 241 PM CDT Thu Oct 8 2026

High pressure of 30.1 inches will cross Wisconsin tonight.
Winds will become southerly on Friday as the high departs and low pressure around 29.2 inches develops in the Northern Plains.
The tight pressure gradient over Lake Michigan will produce breezy southerly winds up to 30 knots from Friday night through Sunday morning. A few gale force gusts may occur in the northern half of the lake Saturday afternoon and evening.

Lighter winds are expected Monday as a weak low pressure trough around 29.7 inches slowly moves from Minnesota to Wisconsin. Look for gusty northwest winds to develop Monday night into Tuesday after the passage of a cold front as high pressure of 30.1 inches builds into the Upper Midwest.

Cronce

MKX WATCHES/WARNINGS/ADVISORIES
WI...None.
LM...None.