textproduct: Detroit/Pontiac

KEY MESSAGES

- A warming trend begins as highs return to the 50s Wednesday and 60s Thursday, except cooler near Lake Huron.

- A slow moving cold front brings the next chance of rain late Wednesday night and Thursday, and remains the focus for additional rainfall Thursday night and Friday.

- Cooler but still near normal temperatures occur behind the front Friday and Saturday.

DTW THRESHOLD PROBABILITIES

* None

PREV DISCUSSION

Issued at 347 PM EDT Tue Apr 7 2026

DISCUSSION...

High pressure covers the entire Great Lakes this afternoon with an impressively cold and dry air mass limiting high temperatures to the 30s, despite full early April sun. These readings are well below normals in the lower to mid 50s and set the stage for another cold night across the region. The afternoon decreasing cloud trend leaves clear sky in place with light north wind shifting eastward this evening for a favorable radiational cooling setup. Temperatures drop into the 20s not long after sunset, but then become steady mainly due to wind increasing from the SE after midnight. There is also some high cloud increase and possibly a few pockets of stratocu from Lake Erie late tonight and Wednesday morning.

High pressure reaches the Atlantic coast as the next low pressure system moves into the upper Midwest by Wednesday afternoon. Lower Mi is between these systems and within a textbook warm advection pattern. Associated isentropic ascent is pronounced on the leading edge of the theta-e ridge but not quite able to overcome low level dry air still feeding in on streamlines off the Atlantic coast high pressure. We end up with high clouds thickening and lowering during the morning along with a virga footprint on radar until shifting northward toward mid afternoon. SE Mi is not fully in the warm sector of the low pressure system with a lingering SE component on the surface wind, however guidance temperatures in the lower to mid 50s are reachable for afternoon highs. The slight onshore wind direction holds readings well down in the 40s toward Lake Huron.

Conditions remain dry and mild Wednesday night until late night arrival of the moisture axis along/ahead of the inbound cold front. Today's 12Z models indicate good agreement on solutions that show the upper Midwest low occluding into northern Ontario while drawing a band of showers into central Lower Mi by Thursday morning. The moisture axis is mature but the boundary leans frontolytic under the southern fringe of the upper level system. Timing is also not great during the morning diurnal instability minimum which limits maintenance of much more than clusters of showers as the band progresses across SE Mi. Blended POP guidance offers a reasonable reflection of these trends from borderline widespread coverage over the Saginaw valley late Wednesday night down to higher end scattered coverage with low QPF across the rest of SE Mi as the front moves through Thursday. Shower potential then peaks Thursday night as the front stalls in the Ohio valley and reactivates aloft over Lower Mi. Timing and intensity of the upper wave again look good among the 12Z model runs as the wave moves in from the central Plains. Nocturnal timing in this case is favorable for low level jet intensification downstream and along the 850-700 mb frontal zone supporting a flare- up of showers and scattered thunderstorms late Thursday night and Friday morning. Consensus of model QPF among the deterministic runs shows a larger footprint of 0.5 inch totals over about a 12 hour event with localized totals up to 1 inch before ending early Friday afternoon.

The surface front stalls across IN/OH Thursday night and never really makes a northward move during the Thursday night/Friday rain event. It is then driven well south into the Ohio valley as precipitation exits Lower Mi Friday. The upper level wave exits eastward leaving subsidence and high pressure to build over the Great Lakes and drive the front southward. Model guidance indicates this inbound high pressure air mass brings dry weather and only drops temperatures down into the 50s (compared to 30s today) for Friday and Saturday.

MARINE...

High pressure centers over the Great Lakes today, leading to drier and less windy conditions. Northwest flow weakens this evening and flips southerly overnight as the center of the ridge translates into the eastern Great Lakes, while low pressure over the central US/Canada border tracks toward Ontario. Pressure gradient constriction occurs as the low approaches, with southerly flow increasing to 25 knots late Wednesday evening. A 60 knot low level jet moves overhead Wednesday night, but low-level stability should prevent comparable gusts from mixing to the surface. Most areas should see gusts capped below 35 knots, with elevated wave heights being the main marine concern. A few gusts to gales cannot be ruled out, but should be infrequent enough to preclude an gale headlines. The low will also slowly draw a cold front across the region late this week, resulting in several rounds of showers with potential for a few rounds of thunderstorms. High pressure then returns to start the weekend with weaker winds and lower wave heights.

DTX WATCHES/WARNINGS/ADVISORIES

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