textproduct: Detroit/Pontiac

KEY MESSAGES

- Rain returns tomorrow morning. Locally heavy rainfall around an inch or greater is possible from Monroe to Port Huron.

- Warming trend next week with temperatures back to normal values.

DTW THRESHOLD PROBABILITIES

* High for ceilings at or below 5000ft tonight and Saturday.

* Low for ceilings and visibilities to fall to 200ft or 1/2SM Saturday.

PREV DISCUSSION

Issued at 308 PM EDT Fri May 22 2026

DISCUSSION...

Upper ridging and western extension of the Canadian surface high pressure will maintain dry conditions through remainder of the today period. Soundings showing some mixing into 25-30 knots within the easterly low level flow through the afternoon, which should keep gust potential to around 25 knots. Increasing gradient flow into this evening will allow for winds to remain elevated into tonight.

Increasing gradient will be associated with a southern stream wave and low pressure system lifting towards the Ohio River Valley out of the Ark-La-Tex. This system is expected to bring the next round of likely rainfall to southeast Michigan ramping up towards midnight and beyond with increasing isentropic ascent ahead of the surface low. Lack of instability and steep lapse rates will preclude mention of thunderstorms for most of the area aside from the Port Huron to Monroe corridor. A favorable zone of 850-700mb fgen lifts across the area tonight through tomorrow morning with PWATs climbing to near or around 1.50 inches. This will support a swath of higher localized rainfall amounts exceeding an inch by the end of tomorrow, which is also tied to the area of low thunder potential. There remains some solutions with this higher swath holding just to the east in Canada. Still a high chance for average amounts of 0.25 to 0.75 inches across the CWA. The general track of the low targets still targets the Port Huron to Monroe corridor with higher end potential.

The surface low passes right through southeast Michigan tomorrow afternoon and evening. Rainfall chances will gradually decrease with its progression later in the day as best forcing is drawn northward. Winds will remain elevated through tomorrow afternoon until weaker winds prevail and flow flips westerly in the wake of the low by tomorrow night. There will a brief break in precipitation Sunday morning before rain chances increase again Sunday afternoon as a secondary wave and front move through. NBM temps on Sunday likely too high and probably more towards more normal values around 70 degrees given the rain chances, cloud cover, and weaker thermal advection.

High pressure spreads across the region bringing a period of drier weather early to mid week with a better signal for above normal temperatures with upper 70s to low-mid 80s. Troughing across eastern Canada during this time does offer some glancing shortwaves that could produce some chances for rain. At this time, chances will be low until there is higher confidence in timing and occurrence.

MARINE...

Strong high pressure is building over Eastern Canada this evening as low pressure lifts up from the Ohio Valley tonight. This will further increase the easterly pressure gradient, allowing winds to gust to 25 to 30 knots into Saturday. Small Craft Advisories are in effect for all nearshore waters.

The low pressure system will also bring widespread rain showers and a chance of thunderstorms to the Central Great Lakes tonight and Saturday. The low will weaken and dissipate late Saturday into Saturday night over Lake Huron, leading to lighter winds for the second half of the weekend. However, another upper-level disturbance will bring a good chance of showers and isolated thunderstorms over Lake Erie and Lake St. Clair on Sunday.

High pressure returns Monday and slips east into the Mid-Atlantic States on Tuesday, maintaining generally light winds.

HYDROLOGY...

A round of steady soaking rainfall is forecast to spread across southeast MI from south to north tomorrow morning as low pressure lifts across the Ohio Valley and eventually through southeast Michigan. Forecast rainfall totals range generally between a quarter inch and three quarter inch during this event. Locally higher rainfall totals of an inch or greater are possible from Monroe to Port Huron. Hourly rainfall rates on the order of a tenth to one quarter of an inch per hour are expected. Overall dry conditions for much of the area over the past 30 days suggests the potential for flooding is low, aside from typical isolated flood prone locations in the urban areas.

DTX WATCHES/WARNINGS/ADVISORIES

MI...Beach Hazards Statement through Saturday evening for MIZ048-049-055- 063.

Beach Hazards Statement until 10 AM EDT Saturday for MIZ083.

Lake Huron...Small Craft Advisory until 10 PM EDT Saturday for LHZ422.

Small Craft Advisory until 4 AM EDT Sunday for LHZ421-441>443.

Lake St Clair...Small Craft Advisory until 10 PM EDT Saturday for LCZ460.

Michigan waters of Lake Erie...Small Craft Advisory until 10 AM EDT Saturday for LEZ444.