Marine Weather and Tide Forecast for South Monroe, MI

AVIATION

Low pressure passing north of the Great Lakes contributes to a strengthening pressure gradient today. Southwest wind becomes gusty to between 25 and 30 kt mid morning, veering westerly this afternoon ahead of a cold front. Moisture pools in ahead of the front with boundary layer clouds developing overhead. Potential exists for MVFR ceilings - mainly north of Metro Detroit. Frontal passage is dry with a shift to northwesterly wind this evening. Broken lower VFR ceilings are favored tonight as wind magnitude wanes. Spotty showers will mainly target the Thumb and Saginaw Bay vicinity.

DTW THRESHOLD PROBABILITIES

* Medium for ceiling at or below 5000 ft this afternoon into tonight.

PREV DISCUSSION
Issued at 353 AM EST Sun Nov 8 2026

DISCUSSION...

A dry and stable airmass remains in place this morning after an extended period of clear skies and subsequent radiative cooling overnight. Temperatures have dropped into the low-mid 30s as of 3 AM, with another few hours of cooling expected to bring lows into the upper 20s in some spots. The decoupled boundary layer sits beneath ongoing WAA where h8 temperatures peak at 7-8 C, meaning as diurnal mixing erodes the inversion, temperatures climb into the mid 50s. Veering vertical wind profiles also show strengthening low level winds throughout the day, which the growing boundary layer will tap into to produce breezy WSW winds gusting to 30 mph during the daylight hours.

Looking at GOES-19 satellite imagery, a band of mid-high cloud is accelerating eastward into Lower Michigan on the nose of a 90-95 knot upper level jet (noted as the dry slot in mid level WV imagery). This moisture corridor represents the lead edge of height falls associated with the mature stacked low over western Ontario, which sends a weak surface front across SE Michigan by early this afternoon. While the frontal passage itself will be dry, subsequent cold advection will add to the moisture pool by establishing moisture flux off of the lake aggregate. Hi-res models show a convergence signal over the Saginaw Valley/Thumb which could lead to shower activity across these portions of the forecast area, so long as lake effect bands do not set up entirely offshore. Elsewhere, stratus expands south for mostly cloudy skies overnight.

Cloud cover and lake induced showers linger into Monday morning before moisture is scoured out by the brief influence of high pressure. Surface pressure during the first half of the week fluctuates between 1010-1020mb in a progressive, low amplitude pressure pattern. The weak nature of the waves has little impact on temperature prospects, with Tuesday actually being the warmest day of the period (highs in the low 60s) despite a surface trough passing through earlier in the day. Reliance on Pacific moisture just does not provide enough depth for any meaningful rain chances over land through Wednesday.

A more pronounced pattern shift arrives late in the week as a much stronger low slides across the Ohio Valley, followed by colder Canadian air crashing in from the north. This could introduce our first shot at mixed precipitation with the arrival of the coldest air of the season.

MARINE...

Strengthening gradient flow materializes across the central Great Lakes today as the next low pressure system clips the northern waterways through early Monday. This initially supports breezy southwesterly winds with gusts peaking between 25 and 30 knots, considering the initial stable warm advection regime. However, as this low exits, winds will veer to the northwest behind the attendant cold front, ushering in the next dose of colder air.
Instability then builds over the warmer lake waters which deepens mixing depths and taps into stronger flow above the lake surface. A Gale Warning remains in effect given the cold advection and consensus in lower column wind speeds. Gusts should hover near the gale threshold across the northern half of Lake Huron this evening through early Monday. Meanwhile, Small Craft Advisories are in effect for the southern Huron nearshores. Expect periods of gusts at/above 25 knots and waves in excess of 4 feet. Quick shifts to shortwave ridging Monday and then back to a troughing pattern with a dry frontal passage develops early next week, with lower potential to reach marine headline criteria.

DTX WATCHES/WARNINGS/ADVISORIES
MI...None.
Lake Huron...Gale Warning from 4 PM this afternoon to 4 AM EST Monday for LHZ361- 362.

Small Craft Advisory until 4 AM EST Monday for LHZ421-422.

Small Craft Advisory from 10 AM this morning to 4 AM EST Monday for LHZ441>443.

Lake St Clair...Small Craft Advisory until 10 PM EST this evening for LCZ460.

Michigan waters of Lake Erie...Small Craft Advisory until 10 PM EST this evening for LEZ444.