textproduct: Detroit/Pontiac

KEY MESSAGES

- Dry weather and near-normal temperatures settle in for the weekend.

- High confidence for above normal temperatures (90+) next week.

DTW THRESHOLD PROBABILITIES

* Medium for ceilings at or below 5,000 feet by mid-morning. Low in the afternoon.

PREV DISCUSSION

Issued at 334 PM EDT Fri Jul 10 2026

DISCUSSION...

Scattered convective activity is ongoing this afternoon, focused along/south of a convergence axis which is situated from roughly Lansing-Ann Arbor-Grosse Ile. Similar to yesterday, these storms are struggling to gain much height due to the mid-level subsidence bubble which has limited their intensity and lightning activity. Still, enough uncapped instability in the lowest 15.0 kft agl exists to keep convective showers and a few thunderstorms going in this same corridor through the evening. A few of the stronger cells have exhibited weak rotation as they encounter backed flow near the Lake Erie shoreline while mean storm motion is west to east. There is thus a very low chance of a brief spin up tornado if any constructive storm interactions can connect with this mid-level rotation. This is a very low confidence scenario as sub-1 km flow is weak (aob 5 knots) and storms are struggling to maintain longevity. As instability wanes and the front continues to sag south, convection comes to an end by late evening.

High pressure then takes residence this weekend, fully dislodging the stalled convergence zone south of the state line. This allows a drier, subsident airmass to expand south into the Great Lakes. Thermal trough will be centered over Quebec/New England, placing SE Michigan within a region of neutral/weak cold advection (weak backing trend in column winds) allowing temperatures to remain seasonable (mid-80s) through the weekend. Northeast flow off of the warm lakes may lead to some patchy fog or low stratus that mixes into diurnal cu for the afternoon hours each day.

Pattern shift back toward July heat is expected early next week. This comes as 500mb heights build toward 600 dam over the northern Plains, with the ridge and its associated theta-e axis folding into the Great Lakes Monday. Global models vary in how compact the ridge is, but agree that it will deflect gulf moisture south of the Ohio Valley. Dewpoints thus forecast to hold at or below 70 degrees which combines with highs in the low-mid 90s to push heat indices into the upper 90s Tuesday and possibly Wednesday. Synoptic pattern points toward a capped environment early in the week as synoptic systems are steered around the ridge and away from SE Michigan. Caveat to this is the less predictable convective influence, which could break down the ridge at a faster pace or add moisture to the environment that is not well handled on these larger model scales.

Shower and thunderstorm chances then increase mid-late week as the northern stream low carves into New England. General consensus is for a more active pattern as the ridge breaks down and mean cloud- layer winds flip from northeast to northwest. This could put SE Michigan in the track of any upstream convection, but will largely depend on how instability evolves across the Midwest/Great Lakes and how aggressive the front is. Temperatures will still be above normal as well with highs in the upper 80s-low 90s through the end of the forecast period.

MARINE...

The frontal boundary that was stalled near Lake St. Clair and western Lake Erie today will slowly sink southward through the evening. Scattered showers and thunderstorms will still be possible through the early evening before conditions dry out. Any isolated storms that do develop may be capable of producing wind gusts in excess of 34 kts. High pressure will build across the northern Great Lakes this afternoon which will maintain north to northeast winds of 10 to 15 kts for much of the area. Gusts may briefly reach near 20 kt this afternoon across southern Lake Huron and Saginaw Bay due to favorable fetch orientation. The high pressure will sink further south on Saturday and Sunday, maintaining benign marine conditions with light winds that becomes variable as the high passes overhead.

HYDROLOGY...

Scattered showers and thunderstorms are ongoing across SE Michigan this afternoon and will linger through late this evening. Isolated cells have produced rainfall rates of a half inch to inch per hour rates, with continued potential for isolated 1" per hour rates through the evening. With the majority of activity expected to stay over Lenawee and Monroe Counties, flooding is not expected although ponding on roadways will be possible.

DTX WATCHES/WARNINGS/ADVISORIES

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