textproduct: Detroit/Pontiac

KEY MESSAGES

- Scattered showers with a few rumbles of thunder return this evening as a cold front works through Southeast Michigan.

- Warm and breezy again Sunday and Monday, but drier.

- Widespread precipitation likely late Tuesday through Wednesday with showers, thunderstorms, and snow possible.

AVIATION

Thin line of showers associated with the cold front is moving through southeast Michigan, though will be mostly clear of the southern terminals to start the TAF period. Predominately MVFR ceilings accompany this front while southwest winds remain gusty to around 25-30 knots. Wind will shift out of the west with time this evening behind the front while gradually declining in strength. Expect MFR stratus to hold through the night before clearing looks to occur in the 12-15Z window tomorrow. VFR will then prevail under mostly clear skies. Mixing potential will offer gusts to around 25 knots by late tomorrow morning through the afternoon as wind direction returns out of the southwest.

For DTW...MVFR ceilings likely to hold through bulk of tonight with clearing skies towards 14Z tomorrow morning.

DTW THRESHOLD PROBABILITIES...

* High for ceiling at or below 5000 ft through tonight. Low Sunday morning.

PREV DISCUSSION

Issued at 344 PM EST Sat Mar 7 2026

DISCUSSION...

Warm sector, marked by temperatures in the mid 60s (dewpoints in the upper 50s), is becoming less favorable for late afternoon and evening thunderstorms. Midday CAPE (250-500 J/kg) has already peaked, and will continue to trend lower as a cold front and its associated frontal circulations pass through. Based on the location of a Lower Michigan surface obs wind shift, the boundary is now approaching the western CWA border with weak shower activity noted in KDTX/KGRR reflectivity data. Drier air has already filled into the mid-levels while slight warming of the 800-700 mb layer has led to weak stabilization and capping. Additional scattered showers with a few rumbles of thunder are still possible this evening, but convective intensity has trended lower suggesting minimal severe risk. Late morning SPC SWODY1 update removed the Marginal Risk overlap for Southeast Michigan, and even the mention of General Thunder. Flow turns zonal in the wake of the front tonight with high confidence in dry conditions tonight, after 03Z. 850 mb temperatures crash below 0C late overnight with the airmass transition, capable of producing lows in the 30s.

The active pattern persists Sunday with 980 mb low pressure crossing central Ontario. Prognostics indicate constriction of the pressure gradient on Sunday as winds back southwesterly. Prevailing speeds should broadly rise in the 20 mph range by midday as low-level winds increase further. Mixing depths will remain fairly shallow, even during the diurnal maximum. 40-50 knot flow should stay trapped above 875 mb (3 kft AGL), but 35 knot flow could mix down and produce a period of gusts ranging from 30-40 mph. The nocturnal inversion settles in quickly Sunday evening ending the higher-end gusts. Seasonably mild conditions extend into Sunday as the latest forecast indicates highs in the upper 50s. Suppressing high pressure over The Southeast washes out as a split-flow configuration begins to emerge within the broader vicinity of the Great Lakes region. No precipitation concerns Monday with temperatures being the main story. Warm and breezy southwest flow helps lift 850 mb temperatures into positive double digit (Celsius) territory supporting daytime highs in the upper 60s.

An amplified pattern evolves upstream mid-week as a cut-off upper low over the Four Corners region dislodges, quickly phasing with the northern stream jet. Rapid deepening of an embedded shortwave feature leads to aggressive height falls across the Midwest and a sharp uptick in confluent southwest flow. This leads to an influx of low-level ThetaE convergence and elevated nocturnal stability, late Tuesday into Wednesday. Potential exists for thunderstorms during this time, but lapse rates are unimpressive and timing of low-level saturation is in question. Wrap-around moisture and a much colder airmass fills in as the surface low exits into southern Ontario Wednesday evening, which favors some post-frontal snowfall into Thursday. If current 2m temperature trends hold, accumulations will be possible once ground temperatures drop.

MARINE...

Cold frontal passage this evening clears out persistent fog as moderate, cooler west-northwest flow develops in its wake. As is typical in this wind direction, strongest winds occur over the northern third of Lake Huron where gusts peak around 30kts. Potential to reach 34kts over these waters continues to be too low to warrant any headlines. Winds over the remainder of the region instead hold at or below 25kts. Departing low pressure allows winds to weaken overnight before another stronger low tracks over northern Ontario Sunday. Locally, the passage of this Ontario low shifts winds back to the southwest Sunday morning as 50-60kt flow develops aloft. Thermal profiles however hold on the neutral to slightly stable side inhibiting the degree momentum is able to mix down to the surface. While a couple gusts to entry-level gales are possible over the central waters of Lake Huron (including the Saginaw Bay), confidence is low given the thermal profile. Instead, peak gusts around 30kts are most likely. A diffuse pressure gradient sets up across the central Great Lakes by late Monday as the Ontario low reaches northern Quebec allowing winds to turn lighter through Tuesday. Active pattern and stronger flow return by midweek as deepening Plains low pressure tracks over the central/southern Great Lakes.

DTX WATCHES/WARNINGS/ADVISORIES

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