Marine Weather and Tide Forecast for Detroit, MI

AVIATION

Height falls in advance of sharp, digging shortwave maximum is leading to synoptic scale ascent over Southeast Michigan this afternoon. Instability is sufficient for scattered to numerous thunderstorm activity this afternoon between 18-21z. Decided to go with TEMPO for TSRA at KFNT southward through the Detroit terminals.
A period of midcloud at/around 050-060 is expected in the wake of the thunderstorm activity this evening with VFR overnight. Strong midlevel subsidence amidst a cool and dry air mass will support quiet VFR conditions Sunday.

D21/DTW Convection...Numerous thunderstorm activity is expected in the airspace between 19-21z. Included a TEMPO at DTW. Low potential for severe at any one particular location this afternoon.

DTW THRESHOLD PROBABILITIES

* Moderate for ceiling 5000 ft or less this afternoon, and low tonight, Sunday.

* Moderate to high for thunderstorms between 19Z and 21Z today.

PREV DISCUSSION
Issued at 1144 AM EDT Sat May 9 2026

UPDATE...

Focus for this afternoon and early evening will be thunderstorm development ahead of a cold front that will bring the potential for embedded isolated to scattered severe thunderstorm development. Have trended PoP values higher for this update noting the very well- defined mid-level wave on water vapor imagery along with the potential for late afternoon upper-level support within the left exit region of the approaching jet streak.

Convective mode favors scattered to numerous rain showers with embedded thunderstorms developing along the boundary with a quick evolution to a broken line or line segments. While a brief semi- discrete mode cannot be ruled out initially, the dominate mode will trend towards this broken line/QLCS setup. Most favorable locations for thunderstorms and stronger development will be roughly along a line and south/southeast from Port Sanilac to Hillsdale from 1PM-6PM. Any storm development will move southeast, so locations downstream have increasing chances for rain showers/thunderstorms through the afternoon.

Kinematic fields will be supportive of organized convection with 0-6 km bulk shear values around 40-45 knots, noting the slightly curved and elongated 0-6km segments within the SR-hodographs. Stretched 6-9km segments will bring good storm-top ventilation and will help support updrafts. Buoyancy remains limited but sufficient with modeled SBCAPE/MUCAPE values ranging between 500-1000J/kg, but the stronger low and mid-level lapse rates aid with the buoyancy equation. The primary hazard with any strong to severe thunderstorm development will be damaging wind gusts with any organized line segments/bowing structures. A conditional tornado threat is also possible given any localized enhanced low-level stretching. Large hail (1") will be more conditional. Caveats to the above thinking will be the upstream shower activity across the west half of the state which will usher in high-based clouds, but this overall setup warrants attention through the afternoon.

PREV DISCUSSION...
Issued at 245 AM EDT Sat May 9 2026

DISCUSSION...

Strong shortwave/500 mb height fall center to track through the northern Great Lakes today. Although the height falls struggle to get much farther south than Saginaw Bay, the optimal timing of the cold front/low level convergence during the afternoon hours should be sufficient for numerous showers and scattered thunderstorms.
Surface dew pts aoa 50 degrees already noted along/near the southern border. With high temperature reaching around 70 degrees, Sbcape around 1000 J/kg seems likely. With steep mid level lapse rates (700- 500 mb) of 7 C/km and rather strong wind fields (45 knots at 850 mb), isolated severe storms are possible with both wind and hail.
Just enough 0-1 KM helicity/bulk shear to suggest a tornado is not totally out of the question before unidirectional low level flow takes over. Far eastern areas, along a Monroe-Detroit-Port Huron line stand the best chance for severe storms, with actually good timing agreement amongst hires solutions (RRFS/ARW/NAM/HRRR) mainly in the 1-5 PM window.

Deep cyclonic flow then develops for the second half of the weekend into early next week, with 850 mb temps progged to bottom out in the -2 to -4 C range Monday morning. Min temps drop into the 30s Sunday night and Monday night; however, there may be just enough wind to help prevent widespread frost/freeze conditions.

The next strong shortwave and associated low pressure system looks to be arriving on Tuesday. Warm front should be active, producing showers as moisture advection is stellar. PW Values start the day on Tuesday around 0.2 inches and surge to 1 inch by early evening.
Showalter index stays positive through the day on Tuesday, and just approaches zero Tuesday night, thus not looking for much in the way of thunderstorm activity.

MARINE...

Southwest winds quickly ramping up this morning as a cold front tracks into the Central Great Lakes region. Wind gusts at or above 25 knots are expected near the shorelines this afternoon, along with scattered strong thunderstorms. Thus, small craft advisories have been issued for most of the nearshore waters. The cold front will pass through around 21-00Z early this evening, allowing for winds to shift to the northwest tonight, but under 25 knots over southern Lake Huron and points south.

Another weaker cold front may clip northern Lake Huron Sunday, otherwise a bit quieter as high pressure builds back in with westerly or northwesterly flow persisting into early next week.

DTX WATCHES/WARNINGS/ADVISORIES
MI...None.
Lake Huron...Small Craft Advisory until 8 PM EDT this evening for LHZ421-422- 441>443.

Lake St Clair...Small Craft Advisory until 8 PM EDT this evening for LCZ460.

Michigan waters of Lake Erie...None.