textproduct: Detroit/Pontiac

KEY MESSAGES

- An extended period of dry weather with seasonable temperatures lasts through the weekend and early next week.

- The next chance of rain arrives with a low pressure system and cold front projected to reach the Great Lakes Wednesday.

DTW THRESHOLD PROBABILITIES

* Low in ceilings aob 5000 feet through the TAF period.

PREV DISCUSSION

Issued at 352 PM EDT Thu Sep 24 2026

DISCUSSION...

Surface high pressure is locked in from southern Quebec across the Great Lakes which has dry and stable conditions entrenched across Lower Mi today. A classic early fall day is the result with temperatures near normal and wind speed down a notch compared to Wednesday. Early day shallow cumulus is long gone by mid afternoon allowing full sun to lift temperatures to highs around 70. Clear sky and light wind follow tonight which set up favorable radiational cooling conditions as high pressure is centered more overhead compared to recent days. This supports guidance offering lows in the lower 40s over a large area of SE Mi outside of metro Detroit. One or two upper 30s reports are also in reach from the typically cooler locations around SE Mi by sunrise Friday.

Double checking upstream conditions today shows a band of showers extending from the upper Midwest into the central Plains associated with a weak mid level wave and surface trough. Model projections show this system quickly overwhelmed by larger scale ridge development as the long wave blocking pattern shifts configuration tonight and Friday. The moisture axis is reduced to a band of mixed high clouds tracking across the central Great Lakes Friday afternoon and evening. Dry and stable conditions are then solidified during the weekend as the mid/upper level ridge and surface high pressure strengthen over the Great Lakes while the nor'easter matures on the mid Atlantic coast.

Consensus of extended time range models indicates changes beginning Monday as the nor'easter moves slowly up the coast Monday night and Tuesday. This promotes deamplification of the trailing mid/upper level ridge over the Great Lakes in a transition toward greater influence of the westerlies that carry multiple short waves across Canada during the mid week period. It takes until Wednesday for the lead wave and surface system to reach the Great Lakes and bring the next chance of rain to Lower Mi. Models also produce a cut-off low around the 4 Corners to southern Plains which is positioned to intercept much of the tropical moisture from "Polo" remnants mid to late next week.

MARINE...

The expansion of a strong Canadian high pressure system derived from Quebec and Ontario into the Great Lakes will provide an extended period of light winds and dry weather through early next week. Some periodic wind gust potential around 20 knots will be possible across southern Lake Huron through this extended time frame, but otherwise, wind gust potential at or below 15 knots is expected. Wind direction will mainly hold from the northeast as high pressure fills in across Michigan.

DTX WATCHES/WARNINGS/ADVISORIES

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