textproduct: Detroit/Pontiac

KEY MESSAGES

- Winter Weather Advisory remains in effect through 10am to account for dangerously cold wind chills of -5 to -15F.

- Another round of accumulating snow will impact the area late tonight through Wednesday early afternoon, impacting the AM commute.

- Arctic air returns Friday and remains across the area through the weekend. Potential for minimum wind chill to fall below -15F Saturday and Sunday mornings.

AVIATION

High pressure builds into the Ohio Valley and southern Great Lakes today with increasing SW wind eventually disrupting the lake effect snow band that has been persistent near PTK overnight. As daytime heating commences, lake moisture is expected to contribute to development of stratocumulus over much of the area through the day. This may scatter out of the Detroit sites this afternoon or evening as the SW flow gains traction and directs the moisture farther north. Flurries will be possible today but accumulating snow is not anticipated. VFR remains favored into this evening before the next clipper arrives from the Midwest overnight. MVFR ceilings and IFR visibility are expected as widespread light snow ensues through Wednesday morning.

For DTW...Observational trends continue to hold the lake effect band north of DTW this morning. Light snow is expected to move in shortly after midnight tonight, with steadiest rates forecast between 09Z and 15Z Wednesday.

DTW THRESHOLD PROBABILITIES...

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

* High for precip type as snow tonight.

PREV DISCUSSION

Issued at 347 AM EST Tue Jan 20 2026

DISCUSSION...

The Winter Weather Advisory will continue as scheduled through 10am this morning to account for the wind chills that have fallen to -10 to -15F across most of the region. There will be some improvement through the day but 850mb thermal trough remains overhead and only improves slightly to the negative upper teens so highs will remain in the mid teens above zero with wind chills rising only to around 0F this afternoon. The corridor of lake effect snow showers has held fairly firm around M59 over night but will drift northward this morning as height rises to the south build northward in between a couple long wave troughs. RH fields show the moisture plume from Lake MI continuing to advect under the strengthening subsidence inversion so expect clouds to flair back up today and can't rule out some flurries with saturation in the 2-4kft layer.

Next chance of accumulating snow arrives tonight and persists through Wednesday morning. A low pressure system will reach southern Lake MI around 12Z Wednesday before curling up to northern Lake Huron by the afternoon. The leading arc of isentropic ascent starts nosing into SE MI after 06Z tonight with best forcing between 09-15Z as a stout low level jet crosses the height field nearly perpendicular before the cold front surges through pushing the lift north and east out of the area. Local probabilistic guidance shows a fairly uniform QPF field across the area, with lower amounts through the Saginaw Valley (due to shorter duration) and near the Ohio border (which catches the first few hours before bulk of forcing lifts north). Higher amounts target 0.1 inch of QPF. National guidance and NBM supports this but does lean a little higher toward 0.15 inches, especially between I94 and I69 with the longest duration of forcing. This all leads to a general 1-3 inch snowfall with higher confidence in 2-3 inches occuring in the aforementioned corridor. Isolated 4 inch totals are not out of the question but at this point don't have alot of support. One thing to watch will be a northern shift which would drop our southern counties totals to possibly under an inch. Some lingering light snow may go on into the evening but little to no accumulation is expected. The cold front will increase mixing depths in its wake and although the strongest jet core will get pushed east, there will still be 35 knots aloft which could get mixed down leading to a period of stronger winds gusts into the 30-40 knot range. Weak shortwave ridge will slide through Wednesday evening into the overnight which should make for a quiet night and abundant cloud cover will keep min temps elevated in the teens thus will give a reprieve from the single digit or negative wind chills.

Train of shortwaves will continue through the trough Thursday and Friday but better forcing gets pushed north so as of now models are lean on any precip/snow Thursday morning but wouldn't be surprised to get some minor accumulations. Thursday will also be the last day before the next arctic outbreak. Highs will reach into the 20s but a an arctic front dropping through overnight will usher in the coldest airmass of the season where 850mb temps fall to around -30C vs the - 22 to -24C we experienced with the last airmass. Highs will only reach the single digits Friday and Saturday with lows currently forecast to be -5 to -10F Friday night and around -5F again Saturday. This would result in wind chill values of -10 to -20F Friday night and around -10F Saturday night. Temperatures then slowly moderate heading into next week but remain below average.

MARINE...

The region remains locked into a large-scale troughing pattern throughout the week maintaining very cold conditions, elevated winds/waves, freezing spray, and periods of snowfall. The Heavy Freezing Spray Warning across the open waters of Lake Huron was extended until 4 PM given the resident arctic airmass and prevailing winds holding near 25 knots with favorable air/water temperatures. Lake effect snow showers wind down later today as broad high pressure builds out of the Tennessee Valley. The next low pressure system swings in on Wednesday followed by a period of possible gales on Thursday. This results from another arctic airmass, which will also require some combination of Small Craft Advisories for portions of the nearshore waters and potential Heavy Freezing Spray Warnings for Lake Huron.

DTX WATCHES/WARNINGS/ADVISORIES

MI...Winter Weather Advisory until 10 AM EST this morning for MIZ047>049- 053>055-060>063-068>070-075-076-082-083.

Lake Huron...Heavy Freezing Spray Warning until 4 PM EST this afternoon for LHZ361>363-462>464.

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