textproduct: Detroit/Pontiac

KEY MESSAGES

- A Winter Weather Advisory remains in effect until 10am for Huron and Sanilac Counties.

- Frigid conditions Monday through Friday with wind chills occasionally reaching 15 below zero or colder. A Cold Weather Advisory is in effect this evening through Tuesday morning for the first episode of dangerous cold wind chills.

- Snow showers around on Tuesday are expected to produce a dusting to 2 inches of accumulation, with a low chance for isolated snow squalls.

- A chance of snow showers exists on Wednesday.

DISCUSSION

Direct absolute vorticity advection within composite trough axis has resulted in a firming of deformation forcing across Southeast Michigan early this morning. Both KDTX and CASET Z products showed steady increase in returns the past 4-6 hours with measured reports of high liquid to snow ratios of upwards of 20:1 to 30:1. NWP signal suggests its going to take a couple more hours for the deformation axis to pivot and sweep out of the region. Will be interesting to look at storm total snow reports in the Thumb with this latest overnight round on top of the lake enhancement from Sunday. The Winter Weather Advisory remains in effect for Huron and Sanilac counties through 10am. Travel will be impacted this morning and no changes will be made to the headlines. Just very weak isentropic descent is forecasted today with a delayed dry air advection response in the midlevels. Not expecting any synoptic scale support for lift today but some supersaturation with respect to ice within the Dendritic Growth Zone will yield flurries from time to time.

Brief shortwave ridging will build across the state this evening as Southeast Michigan resides on the northern edge of the gradient to the surface high passing through the Southern United States. Good signal for southwesterly winds increasing into the 15 to 25 knot range. Dry lower column should allow for a quick temperature drop allowing windchills to drop into the 10 to 20 degree below zero range by Midnight for most of the forecast area. A Cold Weather Advisory is in effect from 7 PM tonight until 10 AM Tuesday. Amplified Clipper shortwave is then forecasted to dig right through Southeast Michigan during the 9-14Z time window Tuesday morning. Decent warm advection response will support lift for a time, but the real limiting factor will be an extremely narrow corridor of saturation between 800-650mb. Deterministic guidance is really struggling with QPF amounts. Looks to be a high PoP/low QPF setup and will carry snow accumulations early Tuesday of around a half inch. Will likely see windchills rise a few degrees around daybreak with the cloud and snow.

Midlevel arctic intrusion of -25C will push through the area Tuesday afternoon and Tuesday evening. Differential warm advection is then anticipated late Tuesday night. There is question and uncertainty with how much lake effect cloud will make it into Southeast Michigan from Lake Michigan as the models could be overforecasting the saturation. Raw model guidance and the current forecast is calling for windspeeds of around 5 knots Wednesday morning. It will be a real close call for windchills to fall to -15C Wednesday morning. Adjustments to the temperature/windchill forecast will likely occur.

A second and larger, colder arctic intrusion is forecasted to dig straight southward into the Great Lakes Thursday and Friday. Coldest of the airmass, 850mb temperatures of -22 to -25C look to be overhead Friday morning. Current windchill forecast Thursday morning has values dropping to -15F for most of the area and -20F for Friday. Additional Windchill headlines appear likely for the end of the week. Low confidence exists on how the cold anomaly will transition and evolve out of the area. Latest data suggests the arctic air will push into the Southeast United States and Mid Atlantic. This scenario may result in a pattern change with quiet weather and moderating temperatures next weekend, a solution the deterministic ECMWF, GFS, and CMC all agree on.

MARINE

Light snow continues across the southern Great Lakes as an expansive low pressure system progresses through the Appalachia region. Departure of this system will reinforce arctic air across the Great Lakes tomorrow and through the midweek period. This will again boost overlake instability, promoting a steep mixing layer that will bring breezy conditions for the next several days. Wind gusts ranging 20 to 30 knots will be likely through this period, with some of these higher end gusts entering Tuesday morning ahead of a clipper system. Moderate freezing spray will be possible. Lake effect snow banding will be likely across the southern Lake Huron basin tonight into tomorrow morning, with widespread light snow possible with the aforementioned clipper system.

PREV DISCUSSION

Issued at 1159 PM EST Sun Jan 25 2026

AVIATION...

North to northwest winds have ushered in lake moisture bringing a mix of low VFR to MVFR ceilings and visibility with isolated/scattered light snowfall/flurries. Heaviest snowfall with the lake effect plume should be east and north of terminals across the Thumb. This initial push of light lake effect showers/flurries with associated MVFR conditions should last through about 09Z. A period of borderline MVFR ceilings with low confidence in timing of light snow/flurries develops after 09Z and through the mid morning hours. Winds continue to veer northwest and eventually to the west by Monday evening. This will flow will continue to offer lake effect clouds and snow showers with a better chance for snow showers during the afternoon. Ceilings continue to hover around MVFR with any snow showers in the afternoon producing MVFR visibility.

For DTW...Best chance through the early morning hours for a dusting to maybe a tenth or two of snow accumulation from lake effect showers will be through about 09Z. Better chance for possible minor accumulations will be Monday afternoon as snow showers/flurries develop off Lake Michigan.

DTW THRESHOLD PROBABILITIES...

* Moderate for ceilings at or below 5000 feet through the morning hours, high by Monday afternoon.

* High in precipitation type as snow.

DTX WATCHES/WARNINGS/ADVISORIES

MI...Cold Weather Advisory from 7 PM this evening to 10 AM EST Tuesday for MIZ048-049-053>055-060>063-068>070-075-076-082-083.

Winter Weather Advisory until 10 AM EST this morning for MIZ049-055.

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