textproduct: Detroit/Pontiac

KEY MESSAGES

- Areas of fog tonight.

- Mild and dry through the week.

DTW THRESHOLD PROBABILITIES

* Low for cigs/vsby to fall below 200ft and/or 1/2SM late tonight.

PREV DISCUSSION

Issued at 338 PM EDT Tue Oct 20 2026

DISCUSSION...

A blocking pattern will result in surface high pressure and ridging being entrenched for most of this week across the Great Lakes yielding quiet weather conditions.

Surface high pressure slides into Quebec with a light east- southeasterly wind component prevailing into tonight. A similar set up tonight compared to last night with favorable radiational cooling conditions. The lingering lake moisture and a little more notable moisture influx off Lake Erie should bring potential again for fog development tonight. It is difficult to pin down where exactly greater coverage of patchy dense fog may develop, but models suggest greater potential exists for a broader area across southeast Michigan to be impacted by some coverage of fog by tomorrow morning.

No major swings in the thermal profiles for the week with persistence of a warmer airmass that brings temperatures that are a few degrees above climatological norms. Afternoon highs will be mainly in the 60s with overnight lows ranging from the mid-upper 30s to mid 40s.

The northern stream across central Canada will send a front into the region that will weaken and stall out as it moves into the Great Lakes tomorrow while longwave ridge amplification ramps back up ensuring. Lack of any deeper moisture will allow dry and around or slightly above normal warmth into the weekend. High pressure centered over eastern Canada will offer potential for slightly cooler temperatures Friday down to around 60 with the northerly flow becoming established for the day. Temperatures quickly recover as thermal ridge builds back into the Great Lakes for the weekend. The next indication of a pattern change is next week as long range ensemble members point toward a stronger Canadian wave that will break down this blocking pattern and open up the door to our next chance a precipitation and cooler temperatures.

MARINE...

High pressure remains over the region through the end of the week resulting in benign marine conditions. The current high slowly shifts east through Wednesday night with a dry cold front then passing southward early Thursday. This front will quickly be followed by another high pressure system that will hold through most of the weekend. Wind gusts will stay below 20 knots through the end of the week. Winds will be southerly through Wednesday before flipping around to the north for Thursday behind the cold front early in the morning.

DTX WATCHES/WARNINGS/ADVISORIES

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