textproduct: Detroit/Pontiac

KEY MESSAGES

- Showers move in this afternoon with some scattered redevelopment overnight; thunder potential is low during the day, and slightly higher tonight.

- Thunderstorms are possible Thursday afternoon, with a low-end chance for isolated damaging wind gusts.

- Turning drier on Friday, although locations near the Ohio border could get clipped by a couple showers.

- Warming temperatures arrive this weekend, followed by much warmer and more humid conditions through at least the first half of next week with periods of storms.

DTW THRESHOLD PROBABILITIES

* Moderate for ceiling at or below 5000 ft this afternoon, high tonight.

PREV DISCUSSION

Issued at 358 AM EDT Wed Jun 24 2026

DISCUSSION...

The synoptic pattern unlocks today as a vertically stacked low dislodges from southeast Manitoba once a speed max aloft moves from the High Plains into the Upper Midwest. Some showers and thunderstorms are still on-going along these features, supported by respective surface reflections and an advancing Gulf feed of higher ThetaE. High-based clouds are beginning to spill downstream into Southeast Michigan early this morning, well ahead of precipitation potential as 24.00Z KDTX RAOB sampled a mid-level environment lacking saturation. Forecast soundings indicate top-down moistening accelerates between 14Z and 18Z today as column winds back zonally in response to preceding height falls. PWATs are projected to double, from about 0.50 inches to over 1.00 inches, by 18Z, aided by low-level flow eventually orienting southwesterly prior to the arrival of expected rainfall. Standard variance exists in CAMs regarding the intensity of the initial round of showers which could arrive as early as 17Z for the Tri-Cities region. Latest PoPs reasonably phase-in higher confidence wording north of I-69 along the leading lobe of CVA, before convective showers/storms fill in further south. Scope of electrification should be limited due to the combination of capping near 10 kft and delayed boundary-layer moistening, which suppresses mean SBCAPE values to less than 100 J/kg.

Showers wane/exit rather quickly between 01Z and 04Z Thursday as drier mid-level air filters in, but questions remain regarding rainfall potential the rest of the night. The occluded low drifts into Lower Michigan and should spur additional shower activity, but coverage ought to become more scattered with this secondary response. Model agreement in placement remains poor, even at this time horizon. Surface dewpoints rise overnight beneath a southwesterly low-level jet, promoting an upward trend in instability. The chance for thunder will be on the rise as the airmass moistens through the night and into Thursday.

The weak aforementioned low gradually crosses central Lower on Thursday as instability continues to build in the presence of sustained moisture transport. Parcel paths could overcome weak sub-5 kft capping early Thursday afternoon. Tall/skinny SBCAPE profiles are then advertised by several Hi-Res solutions, and HREF mean MUCAPE indicates widespread 1+ kJ/kg across the region. Higher 0-6 km shear may be focused south of M-59, which lends low-end potential for convective enhancement and an isolated marginally severe wind threat, should the cap erode as predicted. Thursday also marks the first day where highs could break 80F, primarily for Metro Detroit and points south, which would be the first time since June 13. High pressure then fills in behind the departing low during the first half of the night Thursday with drying and stabilization concluding activity.

Low amplitude shortwave trough stemming from a deep-layer anticyclone over northwestern Mexico will travel across the Four Corners and southern Plains Thursday, reaching the Ohio Valley by Friday. Ridging over the Great Lakes and ENE lower tropospheric flow should prevent the northward creep of most shower/thunderstorm activity from the Ohio Valley system, but the possibility exists for parts of Lenawee and Monroe Counties to get clipped at some point Friday. Dry conditions are forecast for the rest of the area, with readings a couple degrees cooler given the weak flow trajectories tracing northward into Ontario.

Heights begin building overhead Saturday as central CONUS transitions to a longwave ridging pattern over the weekend and into next week. Gradient winds maintain an easterly component Saturday and into Sunday, helping to cap temperatures in the low 80s. Mainly dry conditions expected with a gradual creep in surface dewpoints.

This becomes much more pronounced during the first half of next week as 500 mb geopotential heights spike and approach 600 dam near the confluence of the Mississippi and Ohio Rivers. This leads to an amplified composite ridge axis occupying much of North America, and could significantly dampen the impact of a positively tilted progressive closed low descending across the Pacific Northwest. Latest medium-range deterministic, ensemble, and AI GFS/ECMWF solutions imply confidence in the staying power of this ridge through most of next week, before it begins to retrograde toward the end of next week. Highs in the 90s with dewpoints climbing in the 70s may eventually warrant heat-related headlines. Additionally, convective potential exists as upstream waves traverse the periphery of the ridge.

MARINE...

A low pressure system will gradually advance across the region today and Thursday. This will bring intermittent potential for showers and thunderstorms through this period. Limited wind and wave action expected overall given a weak gradient, but with any stronger storms being capable of producing locally higher gusts.

DTX WATCHES/WARNINGS/ADVISORIES

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