textproduct: Detroit/Pontiac

KEY MESSAGES

- Gusty west-northwest winds to 30-40mph throughout the daylight hours today. Strongest winds occur this afternoon when a few lower 40mph gusts will be possible.

- Scattered-numerous light snow showers this morning-afternoon, with isolated embedded snow squalls possible into the afternoon. Snowfall accumulations of a dusting to half inch for most areas though amounts near an inch possible in the heaviest activity.

AVIATION

This morning and afternoon featured sporadic pockets of some moderate to heavier snow showers that are either now leaving the vicinity of the airspace or are weakening. Snow showers will continue through the later afternoon hours but should mostly remain flurries or light snow showers are dry air begins advecting in from the west. West flow with gusts 30 to 35 knots will remain possible through daylight hours with ceiling heights ranging from high-end mvfr to low vfr (2.5kft to 4kft). Advent of dry air should gradually increase ceiling heights tonight before backing to the southwest, which will advect low stratus cloud cover north of all terminals.

For DTW...Light snow showers will be possible through the remaining afternoon hours, waning into the evening. Otherwise, west flow prevails, gusting up to around 30 knots during daylight hours.

DTW THRESHOLD PROBABILITIES...

* High in ceilings aob 5000 feet today.

* Medium in crosswinds thresholds being exceeded through 4 pm today.

PREV DISCUSSION

Issued at 301 AM EST Fri Dec 19 2025

DISCUSSION...

Secondary arctic cold front is pushing east of the area early this morning ushering in significantly colder air with all of SE MI seeing temps fall into the mid 20s by mid-morning. This rapid cool down will lead to any untreated surfaces with lingering water from yesterday's melt/rain quickly becoming slick/icy. With the core of the airmass not arriving over lower MI until late morning-afternoon, combination of remnant synoptic moisture and lake flux supports scattered to numerous lake effect snow showers through the first half of the day. Overall accumulations stay light, from a dusting to around a half inch for most areas. There remains signal in a subset of high res runs (like the HRRR) for the trailing trough axis over central lower MI to afford some degree of a lower level convergence axis as it pushes into the Saginaw Valley/Thumb. While this would lead to an enhancement of local snow rates, its transient nature due to reliance on the trough still keeps amounts light (aob 1 inch). Worth noting however the overall confidence in this feature manifesting is still fairly low. Snow shower activity begins winding down late afternoon as drier air is fully advected into the lower MI gradually tapering of the lake response.

Main story for today is the return of below normal temps and winds. As mentioned above, core of this colder airmass (850mb temps -15C) is advected in over the course of the morning and afternoon resulting in essentially no thermal recovery through the day. Instead temperatures creep down towards the lower 20s by early afternoon and stay there through tonight. This also leads to increasing winds with afternoon gusts reach the mid/upper 30kt range. Model solutions that push 40kts (or 45mph Wind Advisory criteria) remain very much a minority so running forecast will continue to highlight peak gusts of 35-40mph with only a few isolated pushing lower 40mph. Resultant wind chills hold in the lower teens to single digits throughout the day and tonight.

A moderation in temperatures occurs Saturday as mid-level ridging quickly slides over the Ohio Valley/southern Great Lakes setting up modest southerly WAA. 850mb temps climb back around 0-2C supporting high temps in the mid to upper 30s (near 40s towards the Ohio border). Warm-up is short-lived however as low pressure tracking over northern Ontario drives another arctic cold front across the Great Lakes Saturday night. Some snow/rain-snow showers are possible along the front though the detachment from the parent shortwave keeps any activity very light with minimal QPF. Sunday looks to be the coldest day of the week as -15 to -17C 850mb temps slide directly over lower MI leading to high temps struggling to get into the mid 20s.

Longer range models are in pretty good agreement for a pattern shift next work week as amplifying upper level ridging builds across the central CONUS. This would support above normal (potentially much above normal) temperatures for the mid/late week period.

MARINE...

Gale Warnings are in effect for all of Lake Huron this morning as post-frontal west/northwest flow draws a much colder airmass into the region. Well-mixed boundary layer conditions result in efficient momentum transfer that supports another period of 35-40 knot gusts for both the nearshore zones and open waters. The colder air has also activated the lake effect response, which raises concern for snow squalls throughout the day. High pressure eases the wind field and lake response tonight, leading to a quieter period that extends through daytime Saturday. Another low pressure system, however, fills in quickly behind it to bring a cold front and elevated wind potential to the Great Lakes Saturday night-Sunday. Given the complex nature of today's headlines, will forego adding another headline to the mix for Saturday night even though confidence generally meets criteria for a watch.

DTX WATCHES/WARNINGS/ADVISORIES

MI...None. Lake Huron...Gale Warning until 7 PM EST this evening for LHZ361>363-421-422- 441>443-462>464.

Low Water Advisory until 7 PM EST this evening for LHZ422.

Lake St Clair...Small Craft Advisory until 7 PM EST this evening for LCZ460.

Michigan waters of Lake Erie...Small Craft Advisory until 7 PM EST this evening for LEZ444.

Low Water Advisory until 10 PM EST this evening for LEZ444.