textproduct: Detroit/Pontiac

KEY MESSAGES

- Areas of morning fog lift for mostly sunny skies and high temperatures near 90 this afternoon.

- There is a chance of showers and ordinary thunderstorms toward the Tri Cities and northern Thumb tonight.

- Thunderstorms spread southward while increasing coverage and intensity Thursday and Thursday night. An isolated damaging wind gust and locally heavy rainfall are the primary hazards in thunderstorms.

- Dry weather with near normal temperatures settle in Friday through the weekend.

- A heat wave is possible next week (3 consecutive days of 90+ degrees).

DTW THRESHOLD PROBABILITIES

* Low for visibility 1/2SM or less and ceilings 200 feet or less early this morning.

PREV DISCUSSION

Issued at 353 AM EDT Wed Jul 8 2026

DISCUSSION...

Weak high pressure maintains control of conditions in SE Mi while shifting toward the Atlantic coast and SE States today. After areas of fog, morning sun allows full daytime heating into pockets of cumulus for the afternoon. Light SW wind then helps temperatures finish near 90, a few degrees above normal for early July.

Not far to the NW is the next cold front focusing showers/storms along and ahead of it into the northern Great Lakes. Consensus of the new 00Z regional/global deterministic models and hi-res ensembles shows activity still north of MBS early this evening. This assumes the ongoing upper Midwest convection fades on schedule by early afternoon, before the next round of surface based storms develop farther west again during peak heating. The front and low level moisture axis extend roughly from the Straits into the central Plains late this afternoon ahead of the surface wave also on schedule to ripple along the frontal zone tonight. The low amplitude short wave and surface reflection delay the southward progress of the front which is already subject to a mostly zonal large scale mid/upper level configuration on the south fringe of the northern stream westerlies. This timing limits shower/storm potential to the Tri Cities and northern Thumb later tonight and Thursday morning, a trend represented adequately in the NBM data.

Slow southward progress of the front is also a consistent theme in the latest model solutions for Thursday and Thursday night as the boundary remains on the southern fringe of the northern stream westerlies across Canada. Very slow progression of the long wave pattern nudges the front southward into a favorable position to focus convection across southern Lower Mi, especially during peak heating in the afternoon and evening. Predictability is low on individual low amplitude short waves and/or MCVs, however the front and leading moisture axis with moderate zonal flow aloft still provide a favorable storm environment. HREF and REFS mean surface based CAPE are in good agreement with forecasts in the 1000-1500 J/kg range and with 0-6 km westerly bulk shear near 30 knots adequate for low end multicell clusters capable of an isolated damaging wind gust in line with the SPC Day2 Marginal Risk. However, locally heavy rainfall may end up being the primary hazard as the storm environment carries PW in the 1.5 to 2 inch range and considering the slow pace of frontal passage.

The northern stream westerlies amplify just enough to build high pressure over northern Ontario into the northern Great Lakes early Friday. This pushes the front south of the Ohio border after some lingering showers during the morning. Slightly cooler and less humid air gains ground in the afternoon and especially Friday night when temperature guidance offers lows in the upper 50s to lower 60s. A lengthy period of dry weather follows for the weekend as the northern Ontario surface high builds into Lower Mi with temperatures near or slightly above normal through Sunday. A new round of heat is then on track to increase over the Great Lakes as the mid/upper level ridge builds over the central States. It is trending toward a better position to block Gulf/Atlantic humidity, however a warming trend appears solid for high temperatures returning into the lower and mid 90s during the early to middle part of next week.

MARINE...

The high pressure system that was over the Great Lakes the last several days will wash out across the Appalachia region today which veer wind direction to the south and southwest. A weak pressure gradient will maintain light winds while conditions remain dry for most locations, outside of some rain shower chances across the northern Great Lakes today and tonight. A cold front will then move through the region Thursday which will bring scattered to numerous rain showers along with some embedded thunderstorms. Lingering rain and thunderstorm chances will be possible on Friday across the southern Great Lakes before high pressure builds back in, providing dry weather and light winds through the weekend.

HYDROLOGY...

A slow moving cold front settles through southern Lower Michigan Thursday and Thursday night serving as the focus for numerous showers and thunderstorms, mainly Thursday afternoon and evening, with a chance of locally heavy rain across the area. Rainfall totals averaging around 0.5 inch are most likely with a chance of near 1 inch in scenarios with greater thunderstorm coverage. The slow movement of the front could also produce more than one round of thunderstorms leading to localized totals greater than 1 inch within a few hours time. Flooding potential in this scenario is still limited to ponding of water on roads and minor flooding of urban and other prone areas. Showers and a chance of thunderstorms lingers into Friday morning and then comes to an end Friday afternoon.

DTX WATCHES/WARNINGS/ADVISORIES

MI...None. Lake Huron...None. Lake St Clair...None. Michigan waters of Lake Erie...None.