Marine Weather and Tide Forecast for Monroe, MI

AVIATION

A warm front lifts across the area sparking scattered showers and possible thunderstorms. Scattered showers and possible thunderstorms will last through the morning until around 11-12Z and focused from FNT south to the southern metro terminals. Will still see predominately VFR skies through tonight, but occasional MVFR conditions will be possible with any activity that passes over terminals. It's possible showers linger after 11-12Z, but the greater chances for more showers and thunderstorms is expected early this afternoon associated with the cold front. Have maintained PROB30 groups for this potential. VFR conditions follow thunderstorm chances this evening into tonight.

For DTW/D21 Convection... There will be a low chance for thunderstorms with shower activity through the morning hours.
Greater thunderstorm threat comes by around 16Z and through the afternoon. Isolated severe weather will be possible.

THRESHOLD PROBABILITIES...

* Low for thunderstorms through this morning and again this afternoon.

PREV DISCUSSION
Issued at 338 PM EDT Tue Jul 8 2025

DISCUSSION...

Tranquil conditions persist through the afternoon and evening with seasonal temperatures. Elevated instability increases overnight as a plume of theta-e rich air spreads into the region, with MUCAPE values gradually increasing. While low-level WAA remains limited, low-amplitude mid-level troughing pivots over the Great Lakes and coupled with subtle convergence within the theta-e plume, will bring increasing chances for elevated showers and thunderstorms late tonight through tomorrow morning. By tomorrow afternoon and evening, showers and thunderstorms will turn surface based as instability rises aoa 1000 j/kg, fueled by diurnal heating. Some better forcing will be found along a cold front that will pivot through the Tri- Cities, Thumb and Flint region through the afternoon and early evening hours. Additional weak convergence along lake boundary and intrusion of southwest flow near the border will also be potential areas for shower and thunderstorm development through the day.
Scattered to numerous showers with embedded storm development is expected given the above.

Shear values are modest with 1-6km values of 20 knots, bringing the potential for organized convection of isolated to multicellular variety. The main threats will be stronger gust potential of 45-55 mph and small hail. Slow storm motions will bring the chance for highly localized flooding potential. Please see the hydrology section for additional details. The moisture-rich low-levels will likely be an inhibiting factor for any stronger mentions of gusts reaching severe criteria. Instability wanes while the front clears late tomorrow night, ending all precipitation chances.

Upper-level confluence will reinforce high pressure across the state Thursday with its influence extending into Friday as high pressure washes out across New England and the western Atlantic. This will bring dry conditions through the end of the week with seasonal temperatures. The next chance for showers and thunderstorms will enter in the Saturday-Sunday timeframe. An upper-level disturbance will come onshore across northern California into the Four Corners before shearing out across the Midwest and Great Lakes. An upper- level trough will trail the wave over the northern Plains, with this prefrontal trough/cold front combination bringing the chance for showers and thunderstorms. There still remains questions on phasing of the aforementioned features, but the boost in warm air advection ahead of any troughing feature does bring the chance for some slightly above normal temperatures by Saturday, potentially challenging the 90s through the Metro region.

MARINE...

Light and variable winds remain in place this afternoon and evening as diffuse surface pressure field lingers over the central Great Lakes a bit longer. A weak surface low/trough drifts across northern Lower Michigan tonight and out over Lake Huron Wednesday while gentle winds organize out of the SE. This draws more humid and increasingly unstable air into the region while the governing upper low tracks across eastern Ontario into western Quebec. The combination of forcing and instability ensure periodic thunderstorms Wednesday afternoon and evening, with later rounds tied to the passage of the system's cold front. Ambient dynamics are rather weak which should keep prevailing conditions below Small Craft Advisory criteria, but locally higher winds/waves are possible with some stronger storms that might develop. Shortwave ridging slides east Thursday allowing surface high pressure to build in from the Upper Midwest which facilitates mainly dry conditions across the waterways. A more robust low moves in late Friday into Saturday with renewed potential for showers and storms.

HYDROLOGY...

Scattered to numerous showers and thunderstorms are forecast tomorrow. Storms will be relatively disorganized, but with humid conditions and slow storm movement, storms will be capable of producing torrential downpours. Localized areas may receive over 1 inch per hour, with extremely localized rainfall totals ranging from 1-3+ inches, pending any thunderstorms training or repeated thunderstorm activity. Highly localized flooding of urban areas, small streams, and otherwise poorly drained areas will be possible.
The main threat for flooding will be between 1pm and 9pm.

DTX WATCHES/WARNINGS/ADVISORIES
MI...None.
Lake Huron...None.
Lake St Clair...None.
Michigan waters of Lake Erie...None.