textproduct: Detroit/Pontiac

KEY MESSAGES

- Accumulating snow expected through the afternoon and again tonight. Snowfall amounts mostly in the 1 to 2 inch range across the Saginaw Valley and Thumb decreasing to a dusting near the Ohio border.

- Snow squalls will be possible Sunday morning with additional minor accumulations possible.

- Northwest winds of 30 to 35 mph will be possible Sunday.

- Below normal temperatures developing for the middle to end of next week.

DISCUSSION

Low pressure can be easily seen on satellite spinning across the western Great Lakes this afternoon with precipitation underway across much of southeast Michigan. Isentropic ascent and presence of left exit region dynamics with the 500mb jet will lead to continued precipitation this afternoon. As expected, surface temperatures are hovering in the 33 to 37 degree range. Snow remains the main p-type across the Tri-Cities where lower wet bulb zero heights exist with surface temperatures at 33-34 degrees. Morning guidance has trended slightly to a greater rain-melting snow mix p-type slightly north to Pontiac and towards Flint for much of this afternoon. This trend brings greater potential for snow accumulation holding below an inch up to the I-69 corridor through 7 pm this evening and around a half inch or less up to the M-59. At press time, highest rates focused along the Irish Hills where a snow/melting snow will be favored given the locally cooler profiles at the higher elevation and lower wet bulb zero heights. Have maintained accumulation in this area even as guidance wants to remove it. Thus, up to around half inch will still be possible mostly on grassy/elevated surfaces across these higher terrain areas and cannot rule out achieving an inch through this afternoon either. Morning guidance also pointed towards lower potential for 0.25"/hr rates during a 2-3 hour period this afternoon. Portions of Midland and Bay County still may see upwards of 1.0-2.0 inches of snowfall through 7 pm, though accumulation may be limited here too by the warmer surface temperatures and weaker snow rate potential. Precipitation axis pivots northward after 00Z with a dry slot taking hold of most, if not all of southeast Michigan, for a period of time tonight providing a brief break in precipitation.

Center of the surface low pressure slides across northern lower Michigan and the straights this evening and east of Lake Huron by 7 am tomorrow. A progressive trough will then swing through Michigan on the behind surface low departure. Moisture depths improves from both wrap around moisture and lake moisture boost. Cooling thermal profiles help put better saturation through the DGZ as lift with the trough is able to generate a second round of snowfall. Activity should get started across Midland and Bay County around 3-4 am tonight and will sweep through southeast Michigan through the morning with bulk of more organized snowfall easing by around 10 am tomorrow morning after main trough axis passes east. Progressive nature of this activity should keep accumulations to an inch or less. Accumulations up toward 1 inch will be associated with the potential for more organized snow squall like banding along the trough aided by better mid-level lapse rates. I-69 and points north will be most likely to experience these better snow rates. Intensity may be enough to create variable driving conditions with snow accumulating on roadways as temperatures will have fallen into the mid 20s.

Northwest flow will bring some potential to see isolated to scattered snow showers, mostly towards the Thumb bringing potential for minor additional accumulations through the afternoon. Daytime highs hold around freezing with increasing heights bringing an end to any lingering light snow Sunday evening. Milder air begins to push into the region Monday into Tuesday. Pattern remains active with the next chance for precipitation arriving Tuesday. P-type Tuesday would see a rain/melting snow favored given the milder airmass. A cool down towards more seasonal temperatures or below will arrive by the late week period.

MARINE

A strengthening low pressure system will continue to move over the Great Lakes through the evening before departing into Ontario and QUebec late tonight through early tomorrow morning. This will maintain widespread snow through the area. Departure of the low will usher in a cold front tonight, boosting over lake instability as cold air advection ramps up. Given the degree of instability, confidence to see gust to low-end gales has increased and a Gale Warning is now in place. Small Craft Advisories remain in effect for the outer Saginaw Bay to Port Huron, initially for gusts around 30 knots. As wind direction veers from east to northwest, wave heights quickly increase along the shoreline. A brief ridge of high pressure builds in late tomorrow night to Monday morning, ending gale chances. Breezy conditions below gales to continue into Monday morning.

PREV DISCUSSION

Issued at 1152 AM EST Sat Jan 10 2026

AVIATION...

MVFR cigs this afternoon, trending into IFR late in the day with heavier precipitation. Temperatures above freezing and even dew pts rising to around freezing will make for mostly melting snow. Higher precip rates across the northern sites of FNT and especially MBS will allow for light snow accumulation of an inch or less by early evening. Dry slot attempts to scour out the low clouds this evening. Westerly winds increase tonight, allowing for a return of MVFR clouds late tonight. A period of light snow showers is then expected (8-14z), spreading northwest to southeast as surface cold front tracks through. Accumulations mostly half an inch or less. Northwest winds behind the front tomorrow expected to gust around 30 knots.

For DTW...Mix of rain and melting snow 19-00z. Accumulation not expected on pavement as temps hold above freezing.

Greatest potential for snow showers with minor accumulation will exist Sunday morning. West-northwest winds late Sunday morning and afternoon likely gust around 30 knots.

DTW THRESHOLD PROBABILITIES...

* High for ceiling at or below 5000 through 00z. Low 00z-08z, then high.

* High for rain/snow mix this afternoon and evening. High for snow overnight into Sunday morning.

* Moderate for westerly crosswind threshold being met tomorrow.

DTX WATCHES/WARNINGS/ADVISORIES

MI...None. Lake Huron...Gale Warning from 10 PM this evening to 4 PM EST Sunday for LHZ363- 462>464.

Small Craft Advisory from 10 PM this evening to 10 PM EST Monday for LHZ421-441.

Small Craft Advisory from 10 PM this evening to 10 PM EST Sunday for LHZ442-443.

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