textproduct: Detroit/Pontiac

KEY MESSAGES

- Winter Weather Advisory in effect from 3 AM to 1 PM Wednesday. Total snow accumulations of 1 to 3 inches, with highest amounts between I-94 and I-69.

- Chance of snow showers Wednesday night and Thursday, with some minor accumulation possible.

- Dangerously cold wind chill expected again Friday into the weekend. Minimum wind chill below -10F expected each morning.

AVIATION

Winds turning southwest to southerly tonight will direct lower level lake clouds currently across MBS/FNT further to the north. It looks like MBS will likely holding onto lower VFR ceilings, possibly MVFR at times, with VFR skies for terminals to the south. Low pressure will then move into the region tonight bringing widespread light snow to southeast Michigan. Snow spreads into the area between 07Z-10z with a peak in snowfall focused between 11Z-15Z tomorrow morning. There still remains a chance for a pocket of dry air to reach the southern metro terminals, which may cut into terminals and shorten timing of peak snowfall rates. Snowfall accumulations across terminals will be between 1 to 3 inches with the higher end of these totals most likely favored across PTK and FNT. Expect predominately MVFR to IFR conditions as snowfall moves through. Following the system snowfall will be lake effect snow that kicks in around 16Z and likely last through the afternoon while winds increase out of the southwest. VSBY likely improves with the period of lake effect, but ceilings still likely hold at MVFR.

For DTW...Light snow is expected to move in after 07z tonight, with steadiest rates forecast between 10Z and 15Z Wednesday.

DTW THRESHOLD PROBABILITIES...

* High for ceilings aob 5000 feet tonight and Wednesday morning.

* High for precip type as snow tonight.

PREV DISCUSSION

Issued at 349 PM EST Tue Jan 20 2026

DISCUSSION...

High amplitude longwave wave troughing of arctic origin will briefly retreat northward over the next 36 hours, affording a window of meaningful northwest flow to yield yet another clipper system for late tonight and Wednesday. Arctic air entrenched late this afternoon maintaining a wind chill invof zero degrees. Coldest conditions noted this evening, as a brief window of favorable radiational cooling provides a dip in temps before a pattern of warm air advection emerges overnight. Minimum in wind chill around -5c before rising through the night.

Strengthening advective process with time nets a period of stronger moist isentropic ascent immediately downstream of the inbound wave during the morning hours Wednesday. This leads to widespread accumulating snowfall for the Wednesday morning commute. Cross section analysis suggests a window of productive snow growth as maximum upward vertical motion insects a favorable thermal profile. Onset expected within the 07z-10z window from west to east, with a peak in snowfall rate in the mid-late morning hours before tapering off by early afternoon. Projected qpf arrives within the .10-.20" range most locations, yielding a general swath of accumulation of 1 to 3 inches - highest amounts between I-94 and I-69. Worthy advisory level setup given the timing. Prolonged warm air advection will lift temperatures toward the freezing mark by afternoon. South to southwest wind gusting 25 mph thru the day.

Additional shortwave energy working through broader cyclonic flow lifts across the region Wednesday night and Thursday. This will occur as an initial weaker period of cold air advection develops. Ill-defined environment to offer a greater signal for snow potential, but overall conditions will be conducive to some degree of snow shower development with augmentation from ongoing lake moisture flux. Forecast will continue to highlight broad, minor accumulation potential of a dusting to half an inch at this stage. Little diurnal temperature recovery Thursday as the advective process gains traction. This will park readings mainly in the teens to lower 20s, with daylight wind chill back in the single digits.

Organized southward penetration of the polar low to near lake Superior Thursday night and Friday sets the stage for the strongest arctic intrusion this winter. Pronounced nocturnal cold air advection will aggressively send wind chill spiraling downward Thursday night, landing a minimum in apparent temperature Friday morning to around/below -10F. Moisture quality remains lean, but the arctic frontal passage and trailing height falls may offer a limited opportunity for snow shower development during this time.

High magnitude cold will mark conditions Friday into next weekend. Minimum in 850 mb temperatures around -30c entrenched on Friday means high temperatures of single digits - or near record territory for a record low maximum for the day. Coldest conditions likely Friday night-Saturday morning with a headline worthy wind chill bottoming out below -15F. A very dry and stable profile through the first half of the weekend with sprawling high pressure in control. Eye on the potential winter storm brewing for the southern conus for the latter half of the weekend, as the far northern expanse of associated mid level level dynamics and accompanying deeper moisture may pivot nearby just to the south.

MARINE...

Broad high pressure out of the Tennessee Valley has provided a period of drier conditions today with modest westerly gradient winds persisting. Large-scale troughing takes over again tomorrow with an embedded system bringing slightly milder conditions and additional snowfall. Gales are possible Thursday, mainly for portions of southern Lake Huron, as the next arctic airmass moves in. This may also require some combination of Small Craft Advisories for portions of the nearshore waters, and renewed Heavy Freezing Spray Warnings for the open waters of Lake Huron. Much colder conditions settle in for the weekend with additional periods of snowfall, northwest flow, and freezing spray.

DTX WATCHES/WARNINGS/ADVISORIES

MI...Winter Weather Advisory from 3 AM to 1 PM EST Wednesday for MIZ047>049-053>055-060>063-068>070-075-076-082-083.

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