Marine Weather and Tide Forecast for Manchester, MI

DISCUSSION

Southeast Michigan holding position late this afternoon immediately downstream of a closed mid level pivoting across Wisconsin. A warm but drier profile now entrenched, with a brief window of deeper stability in residence now evident by a simply a limited coverage of diurnal cu. Dry and stable conditions to hold through at least 00z, with attention tonight shifting to a mid level perturbation shearing out ahead of the main height fall center. Noted increase in forced ascent attendant to this feature set to sweep across the local area 01z-07z. Renewed boundary layer moistening will commence at the same time, offering at least a weakly unstable low level environment.
Mixed signal yet across the model solution space on possible degree of destabilization, with variability noted in dewpoint recovery by as much as 8-10 degrees. This will impact both prospective coverage and vigor of any convective development within this window. Assuming the upward vertical motion field can overcome residual capping issues, then potential exists for cells to attain greater updraft depth given very steep mid level lapse rates. Background wind field more than sufficient to offer organization to any vigorous updrafts.
This conditional setup carries enough potential should greater instability materialize to warrant an upgrade in the Day 1 SPC outlook to a slight risk for southern portions of the area, highlighting a damaging wind gust and hail threat. A secondary window exists for sub-severe convective development with the actual cold frontal passage late tonight.

Mid level low offers greater influence on conditions to start the weekend, with the circulation center passing thru northern lower MI during the daylight hours Saturday. Cold front exits to the east Saturday morning, with ensuing cold air advection battling daytime heating throughout the day. Minimal thermal recovery expected off morning lows. Temperatures parked in the upper 50s to lower 60s.
Notably breezy conditions as mixing capitalizes on a firm west- southwest gradient. Gusts in excess of 30 mph Saturday afternoon.
Moist cyclonic flow engaging daytime heating will maintain a chance of showers. Seasonably cool conditions persist Sunday under deeper layer northwest flow. Aside from a broad, thicker diurnal stratocu field, generally benign weather conditions to finish the weekend as general subsidence takes control.

Cooler and drier profile maintains residence Monday as low level northeast flow governs conditions under building high pressure from the north. A high amplitude, slowly evolving large scale pattern emerges for the midweek period. Southeast Michigan likely holds position between the high to the north and organizing low pressure to the west. Potentially unsettled conditions at times this period, depending the pace and trajectory of the closed low. Maintenance of east flow with prospective cloud/shower potential on the rise will keep temperatures on the cooler side of average through the rest of the week.

MARINE

Low pressure tracks over Lake Superior this evening sweeping a respectable cold front late this evening. A broken line of showers and storms likely develops in advance with isolated embedded strong to severe thunderstorms possible. Moderate west-southwest winds follow Saturday with the strongest winds (20-30kts) expected over the southern half of the region where the gradient is strongest.
Small craft advisories have been issued for all nearshore waters daytime Saturday as a result. Low fully departs Sunday shifting winds to the northwest. Gusts peak near 20kts during the day before weakening overnight as weak high pressure slides overhead.

PREV DISCUSSION
Issued at 149 PM EDT Fri May 16 2025

AVIATION...

Ample dry air noted through most of the column per 16.12Z KDTX RAOB has held onto VFR SKC conditions into the afternoon hours. Coverage of FEW to SCT cumulus now showing up on satellite as the afternoon progresses, along with deepening mixed-layer to around 6 or 7 kft AGL.
Expect some occasional gusts of 15-20 knots to mix down during peak heating, otherwise, sub-10 knot surface winds steadily back toward the southeast with time. Monitoring potential for another round (or two) of storms late this evening and overnight with a potent shortwave moving through. In addition to lightning, these storms could produce a brief period of gusty wind, including a microburst or two. Time of arrival and intensity differences still exist from north to south with this convective activity.

For DTW/D21 Convection...Potential exists for convection tonight, mainly from 04Z to 07Z. Low chance also exists earlier for the three Metro-area terminals from 02Z to 04Z, prior to the arrival of the main. Dry air aloft lends a gusty wind threat and a non-zero chance for a microburst.

THRESHOLD PROBABILITIES...

* Medium for ceiling at or below 5000 feet tonight, then high Saturday morning and midday.

* Moderate in thunderstorms after 02Z tonight.



DTX WATCHES/WARNINGS/ADVISORIES
MI...None.
Lake Huron...Small Craft Advisory from 8 AM to 10 PM EDT Saturday for LHZ421-422- 441>443.

Lake St Clair...Small Craft Advisory from 8 AM to 10 PM EDT Saturday for LCZ460.

Michigan waters of Lake Erie...Small Craft Advisory from 8 AM to 10 PM EDT Saturday for LEZ444.