textproduct: Detroit/Pontiac

KEY MESSAGES

- Numerous to widespread showers with a rumble of thunder are on schedule to move in this afternoon and continue through tonight. A few of the strongest storms will be capable of 40 mph wind gusts and small hail.

- Below normal temperatures return for Wednesday with scattered showers.

- A warming trend is then on schedule to carry temperatures into the upper 70s to lower 80s this weekend.

DTW THRESHOLD PROBABILITIES

* Very low for thunderstorms this evening into tonight. * High for cigs aob 5000 feet tonight into Wednesday.

PREV DISCUSSION

Issued at 357 AM EDT Tue May 12 2026

DISCUSSION...

Temperatures are settling into frosty lower to mid 30s across SE Mi, except for the immediate Detroit area. Legit freezing conditions are also noted toward the interior Thumb leading up to sunrise. From here, readings climb steadily through the 40s during the morning as the cold high pressure air mass is displaced eastward by the next low pressure system moving into the upper Midwest. This system is on schedule to bring the next round of showers and thunderstorms this afternoon and tonight.

Upstream observational data and model analysis fields indicate elevated activation of the warm front over the upper Midwest as moisture transport accelerates into the system. It has a hybrid Pacific/Gulf moisture axis maturing in the 850-700 mb layer judging by model theta-e fields, more than adequate for elevated convection when driven by a 50 kt low level jet. What has developed in model solutions over the last few runs is a more pronounced effect of dry air in the low levels across SE Mi this afternoon. This results in a POP/QPF gradient from just a low chance near the Ohio border up to near categorical toward the Tri Cities. It shows up in the regional deterministic solutions as well as the HREF and REFS mean QPF as the models hone in on the moisture transport maximum into the northern Great Lakes.

Thunderstorm potential transitions from elevated this afternoon to surface based this evening. There is good model agreement in placement of the surface low near the Straits by midnight which pulls the warm front into central Lake Huron and draws the warm sector across southern Lower Mi. Storms are expected to be ongoing along the trailing cold front crossing Lake Mi around 00Z with the forecast focus being on coverage and intensity as storms reach SE Mi toward midnight. The storm environment offers a strong wind profile that ranges from 50 knots of 0-6km bulk shear at 03Z this evening down to a still respectable 35 knots by 09Z. The limiting factor is instability that fails to hold up as HREF mean MUCAPE struggles to hold 500 J/kg as activity moves through SE Mi. A few stronger storms are in play as the pattern reaches the I-75 corridor, however a weakening or disorganizing trend is likely as weakening updrafts struggle to hold up against the strong wind field. This body of evidence supports the general thunder SPC outlook until the cold front sweeps eastward by 12Z Wednesday.

This low pressure system continues moving slowly eastward during Wednesday despite a respectable occlusion still showing up in model projections. The occlusion maintains a mid level moisture axis and 500 mb cold pool capable of supporting scattered afternoon instability showers across SE Mi. Afternoon max temperatures also drop back below normal, into the 50s most areas, especially if rain is a factor against the diurnal trend. At least lingering clouds strongly limit frost potential Wednesday night.

The transition toward a more zonal large scale mid/upper air configuration is on schedule for the late week period. It is preceded by a sharp mid level ridge and broad surface high pressure to ensure dry weather Thursday. Low pressure well north in central Canada then gets the warming trend underway with a pattern of showers in the Great Lakes by Friday. Temperature guidance has trended significantly warmer for Saturday and Sunday with upper 70s and lower 80s being offered each day. Zonal large scale flow is not a stable/long lasting configuration which is shown in extended range guidance solutions that reamplify the pattern early next week, except this time with the trough farther west and warmer for the Great Lakes compared to recent days.

MARINE...

High pressure departs and washes out across New England this morning which will support southeast flow through the day. A low pressure clipper system will then progress from the northern Plains into lower Michigan late tonight into Wednesday. The pressure gradient will strengthen as a result and will increase the magnitude of southeast flow, producing gusts ranging 20 to 25 knots. This will quickly elevated wave heights aoa 4ft across the Lake Huron shoreline and through the Saginaw Bay, where Small Craft Advisories remain in place. Advisories have also been expanded to Lake St Clair and Lake Erie for tonight and Wednesday.

Passage of the low will veer wind direction from southeast to northwest by Wednesday afternoon. A lull in wind speeds and wave heights will be likely as the low progresses directly over the state. However, the northwest flow will accelerate cold air advection, improving mixing depths which brings renewed gust potential towards 25 knots leading into Thursday.

DTX WATCHES/WARNINGS/ADVISORIES

MI...Freeze Warning until 8 AM EDT this morning for MIZ047>049-054-055- 062-063-070.

Frost Advisory until 8 AM EDT this morning for MIZ053-060-061-068- 069-075-076-082-083.

Lake Huron...Small Craft Advisory from 4 PM this afternoon to 10 PM EDT Wednesday for LHZ421-422-441>443.

Lake St Clair...Small Craft Advisory from 10 PM this evening to 10 PM EDT Wednesday for LCZ460.

Michigan waters of Lake Erie...Small Craft Advisory from 10 PM this evening to 10 PM EDT Wednesday for LEZ444.