textproduct: Detroit/Pontiac

KEY MESSAGES

- Dry and pleasant weather conditions will persist into Wednesday.

- Areas of dense fog expected again Tuesday morning.

- Rain chances increase during the latter half of the week with cooler temperatures expected.

DISCUSSION

Blocking pattern still in place across the conus with the Great Lakes locked under the stacked ridging. Local weather stays quiet through Tuesday with the ridge in place but the ridge will begin to slowly shift eastward as the blocking low off the east coast releases allowing for a more active mid week stretch.

Center of the surface ridge passes over lower MI tonight leading to another calm and clear night with varying degrees of fog across the area. Any fog will again burn off quickly in the morning as temps once again rise into the 70s. Southwesterly winds return on Tuesday as the center of the high drifts off to the east while the positively tilted mid/upper level trough folds over the region. This will allow for a boost in high temps by a couple degrees into the mid 70s with the added warm advection. 850mb temps should increase from the current upper single digits, into the mid teens. Though high temps mid week will be tempered by the incoming clouds and rain, we will see a boost in low temps Wednesday night with temps holding in the mid 60s.

As for the aforementioned clouds and rain, a frontal boundary will stretch from the broad parent low over central Canada down through the Midwest and southward to a cutoff low and surface reflection over the four corners. The front will stall mid week just to our west before slowly pushing east of the area Thursday night. This will lead to a long duration light rainfall event with periods of moderate rain associated with any mid level waves riding up along the front late Wednesday into Thursday night. The cutoff low will absorb remnants of a Pacific tropical system adding high moisture content to the airmass with a strong southwesterly low level jet ushering some of this moisture into the region. Higher rainfall totals will occur west of SE MI, with the front becoming more progressive once it reaches us which will limit totals somewhat locally. At this point we're still looking for around a half inch to three quarters of an inch of rainfall over the 36-48 hour window. There remains a low chance of some embedded thunder over the area mainly Thursday when a strong 50 knot low level jet pushes a mid level wave just south of the area with a theta e plume surging into SE MI which may be enough forcing to allow some convection.

Friday we could be dealing with some post frontal stratiform light rain depending on how fast the incoming surface high can push into the area. Regardless, we are in for a cool weekend as the thermal trough sets up and sits over the region. High temps will only reach into the 60s with lows down into the low 40s.

MARINE

Sprawling high pressure will slowly track through the central Great Lakes through tomorrow, leading to light and variable winds mainly under 15 knots. South to southwest winds will then increase ahead of the next cold front, which slowly moves through on Thursday. With the warm advection leading to more stable profiles and showers moving through during this timeframe, wind gusts are expected to top out only around 25 knots. A better chance to briefly exceed 25 knots exists behind the front Thursday evening/night with cold advection, as 850 MB temps lower into the mid single digits by Friday morning.

Another large area of high pressure building in on Friday and Saturday will promote light winds for the first half of the weekend. A stronger low tracking through the northern Great Lakes for the second half of the weekend brings another opportunity for winds to reach or exceed 25 knots over lake Huron.

PREV DISCUSSION

Issued at 107 PM EDT Mon Sep 28 2026

AVIATION...

Deep layer stability held within low and mid level ridging will continue to limit cloud production this taf period. The surface high is forecast to drift across the area tonight. Not nearly as favorable of an environment to encourage greater advective fog development off lake Huron as noted last night as prevailing wind turns more variable. With that, the combination of a clear, light wind and sufficient near surface saturation may encourage some areas of radiational fog late tonight. Forecast will continue to highlight prospective IFR to MVFR visibility restrictions for all lcoation, while affording further refinement to below IFR should trends become more definitive on a greater coverage of dense fog.

D21/DTW Convection...No thunderstorms forecast through the TAF period.

DTW THRESHOLD PROBABILITIES...

* Low for ceiling/visibility at/below 200 ft / 1/2 SM early Tuesday morning.

DTX WATCHES/WARNINGS/ADVISORIES

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