textproduct: Detroit/Pontiac

KEY MESSAGES

- Winter Weather Advisory in effect through Tuesday morning for a combination of winter hazards.

- Potential for lake effect snow showers through tonight, particularly between M 59 and I 94. Accumulation from a dusting to locally up to 2 inches possible.

- Dangerously cold wind chills of -5 to -15F tonight into Tuesday morning.

- Another round of accumulating snow arrives late Tuesday night and Wednesday, 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.

DISCUSSION

High magnitude cold air advection well underway late this afternoon. The ongoing advective process within a firm west-northwest gradient contributing to cratering wind chill in blustery conditions as improving convective depth captures a 30-35 knot wind field just off the surface. Gusts peaking into the 40 to 50 mph at times. Lake Michigan moisture flux in west-northwest flow yielding a solid downstream lake effect response within the background of mid level cyclonic flow, as focused areas of convergence continue to direct scattered to numerous bursts of snow showers into the typically prone belt between I-69 and I-94. Perpetuation of this activity expected through tonight in some form, but with some nocturnal contraction and possible strengthening of convergence supporting a transition toward one or more dominant linear bands. Inherent variability in accumulation potential with expectation for some fluctuation in trajectory, duration and magnitude. Less ideal microphysics with snow growth above the dgz may favor a drier and more powdery/granular snow carrying less accumulation efficiency. Dusting to less than an inch most locations, but with locally higher amounts plausible within heavier bursts within the M-59 to I-94 corridor. Minimum in wind chill Thursday morning arrives in the vicinity of -10 to -15 most locations. The thumb region and areas south of I-94 are most vulnerable to a dip below this mark. All told, combination of lingering gustiness this evening, continued lake effect potential and the notable drop in wind chill into tonight best highlighted with the ongoing Winter Weather Advisory to maintain a consistent message.

Modest 24 hour recovery in the upper height field noted Tuesday and Tuesday night, as the governing lower height anomaly temporarily retreats northward. Prevailing low level westerly flow with arctic air entrenched will maintain some degree of downstream lake moisture flux through the daylight period. The existing lake cloud maintains the possibility for some very light snow/flurry production, but with limited accumulation potential given unsupportive microphysics inherent within the resident arctic profile. Daylight wind chill holding below zero degrees. The arctic cold will moderate slightly into Tuesday night as warm air advection briefly takes hold, with coldest conditions likely during the evening before slowly rising.

Shortwave noted on water vapor late this afternoon ejecting southeast across British Columbia projected to accelerate through the base of the broader central Canadian longwave trough over the next 36 hours, reaching the great lakes Wednesday morning. Associated ascent tied to ongoing warm air advection arrives locally early Wednesday morning. Supportive moisture quality and depth to generate a period of accumulating snow. Probabilistic data points to a general accumulation residing mainly within the 1 to 2 inch range. The advective process will bring temps back into upper 20s/lower 30s, offering a brief reprieve before the trailing cold front arrives late in the day. Increase in wind magnitude within the immediate post-frontal environment may bring some gustiness to 40 mph Wed afternoon. Yet another wave embedded within the northwest flow could present a quick shot for accumulating snow Thursday morning.

Polar low set to take residence just north of lake Superior to finish the work week. Attendant arctic front marking the coldest air of the season /850 mb temps below -30C/ currently projected to arrive Friday. The frontal feature, possibly in conjunction with still less-defined shortwave energy, may offer another round of light accumulating snow. More noteworthy will be the extended stretch of high magnitude cold expected to persist through the remainder of the forecast period and likely right through the end of the month. Multiple days of sub-zero wind chill with the likelihood of headline worthy readings at times.

MARINE

A low pressure system producing strong gusts and freezing spray for much of the central Great Lakes exits into Quebec tonight. This allows the pressure gradient to slowly relax this evening which causes gusts to drop below gales, as expected. The Heavy Freezing Spray Warning remains in effect tonight and into Tuesday given the resident arctic airmass and prevailing winds holding near 25 knots across the open waters of Lake Huron. Another extension in time may be needed for the Heavy Freezing Spray Warning for the rest of Tuesday given the latest sustained wind trends and expected unmodified air/water temperatures. The region remains locked into a large-scale troughing pattern throughout the week maintaining very cold conditions, elevated winds/waves, areas of heavy freezing spray, and periods of snowfall. The next period for potential gales arrives Thursday amidst another arctic boundary with some combination of Small Craft Advisories possible for portions of the nearshore waters.

PREV DISCUSSION

Issued at 1220 PM EST Mon Jan 19 2026

AVIATION...

Westerly winds sustained aoa 20 knots with gusts aoa 35+ knots continue this afternoon, leading to some blowing snow and visibility reduction at times. Otherwise, chaotic ceilings and big breaks in the clouds with still a risk of a snow squall hitting the airports during the daytime hours, in addition to some light snow showers. Wind and coverage of activity diminishes this evening and tonight, but concern for a narrow lake band(s) to set up between the M-59 and I-94 corridors, which could put down an inch or more of fluffy snow. PTK seems to have the best chance and longest duration for snow shower activity tonight into tomorrow morning. Still, there is a low risk the band sets up around KYIP/KDTW. Either way, airmass is so cold, going to be easy to get very light snow showers from time to time into Tuesday morning. MBS has the best chance of being ceiling free through much of the night.

For DTW...VFR cigs outside of any periods of snow showers/blowing snow reducing cigs and visibilities. With winds still gusting around 35 knots, can still expected short lived IFR/LIFR visibilities in snow showers and blowing snow in line with upstream obs for several more hours. This evening and tonight remains a challenge determining if terminal will be downwind of the Lake Michigan plume or just south, and will leave in the prob30 mention for snow under 1 mile until confidence increases one way or the other.

DTW THRESHOLD PROBABILITIES...

* Medium in ceilings aob 5000 feet through tomorrow.

* High to exceed crosswind threshold this afternoon.

* Low in visibility below 1/2SM in blowing snow through 22Z today.

* High for precip type being snow.

DTX WATCHES/WARNINGS/ADVISORIES

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

Lake Huron...Heavy Freezing Spray Warning until 10 AM EST Tuesday for LHZ361>363- 462>464.

Gale Warning until 10 PM EST this evening for LHZ362-363-421-422- 441>443-462>464.

Lake St Clair...Gale Warning until 7 PM EST this evening for LCZ460.

Michigan waters of Lake Erie...Gale Warning until 7 PM EST this evening for LEZ444.

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