Marine Weather and Tide Forecast for St. Francis, WI

UPDATE
Issued 612 PM CDT Sat May 9 2026

Forecast details remain on track early this evening. Models still suggest overnight lows will be in the mid to upper 30s.
While areas of light frost are expected inland from Lake Michigan, projected temperature and wind conditions overnight still remain above frost advisory criteria at this time.

CMiller

SHORT TERM
Issued 130 PM CDT Sat May 9 2026

This afternoon through Monday:

Another mild and breezy afternoon with high based cumulus clouds is occurring. The breezy nwly winds are associated with the passage of a cold front which will mark the beginning of a cool period lasting into Monday. Lighter nly winds and cold advection will continue tnt, including areas of frost well inland from the lake. Temps are not quite cool enough for an advisory at this time.

A shortwave trough within nwly flow aloft will then bring another round of high based cumulus clouds and scattered sprinkles for Sunday afternoon. High temps will range from 55-60F across srn WI. High pressure moving into nrn MN will then reach srn WI by Mon AM with low temps once again in the 30s. A Frost Advisory will likely be needed for portions of srn WI Sun nt/Mon AM. The high pressure area will gradually shift ewd on Mon with lgt sly winds not developing until late in the day.
High temps will range from the upper 40s at the Lake MI shoreline to around 60F over south central WI.

Gehring

LONG TERM
Issued 130 PM CDT Sat May 9 2026

Monday night through Saturday:

Models continue to support a fairly strong shortwave trough and associated wave of low pressure tracking from Canada to central WI on Tue. A well organized swly low level jet of 45-50 kt and warm, moist advection pattern will bring sufficient moisture and lift for widespread rain and perhaps scattered elevated convection.
There will be just low chances for sfc based convection with the cold frontal passage late Tue afternoon and evening.

High pressure will then follow for Wed nt-Thu AM followed by a jet stream pattern change to quasi-zonal for late next week.
This will bring a return of warm and humid conditions and increasing rain chances.

Gehring

AVIATION
Issued 618 PM CDT Sat May 9 2026

Dry conditions and VFR skies will persist tonight into tomorrow afternoon. Light northwest winds will come around to westerly following the passage of a cold front after 06Z.

Tomorrow, breezy northwest winds return with gusts to 20 knots.
Widespread cu with bases around 5000 to 6000 feet will form during the afternoon hours leading to SCT to OVC VFR skies and may produce a few sprinkles.

CMiller

MARINE
Issued 130 PM CDT Sat May 9 2026

Low pressure around 29.5 inches east of Lake Superior this afternoon will move into southern Quebec tonight. Its trailing cold front will continue to move across Lake Michigan this afternoon. Westerly winds ahead of the front will veer northwest with the frontal passage. Gusty northwest winds are expected near the western shoreline this afternoon. A backdoor cold front will then sag southward across the lake this evening through tonight, with a period of north to northeast winds behind it.

High pressure around 30.3 inches is then expected to move from southern Manitoba on Sunday to over Lake Michigan by Monday morning. Relatively light and variable winds are expected during this period. Low pressure around 29.7 inches should then move east southeast across the region Tuesday, with increasing south to southeast winds ahead of it, veering west to northwest behind it for Tuesday night into Wednesday.

Gehring

MKX WATCHES/WARNINGS/ADVISORIES
WI...None.
LM
Small Craft Advisory
LMZ643-LMZ644-LMZ645-LMZ646 until 7 PM Saturday.