textproduct: Detroit/Pontiac

KEY MESSAGES

- A Cold Weather Advisory is in effect for areas north of I-96 where winds chills of 15 to 20 degrees below zero are possible.

- Intervals of flurries or light snow showers possible at times through Saturday with minor accumulations possible.

- Warming trend early next week with highs climbing into the 20s Sunday onward.

DISCUSSION

A sharp gradient in cloud cover is observed across SE Michigan this afternoon, with the moisture delineation currently extending from roughly Traverse City-Pontiac-Detroit. North of this boundary, clearing skies set the stage for prime radiative cooling overnight for the Saginaw Valley and Thumb with partial clearing into the northern suburbs. A Cold Weather Advisory has been issued for these locations as wind chills as low as -15 to -20 degrees are expected, with the coldest winds chills in the Thumb region due to clear skies, slightly elevated winds (around 10 knots), and closest proximity to the arctic airmass. Opted to exclude Washtenaw-Wayne- Lenawee-Monroe from the advisory with this update due to a persistent stream of stratocu off of Lake Michigan that will limit radiative cooling overnight. Should clearing shift further south, the headline may need to be expanded.

Low level convergence along the boundary has started to emerge this afternoon, with models generating a weak low in its vicinity over western Michigan. This occurs as a mid level deformation axis and shearing vorticity advection sag across the Great Lakes tonight and Friday. The result is scattered snow shower potential overnight, mainly south of the gradient where low level moisture is still prevalent. Light accumulations of a dusting to half inch are possible by Friday morning, generally staying south of M-59.

Waning moisture quality expected through the day Friday in the post- deformation regime as wind direction shifts to the north and dry arctic air spills into SE Michigan. Even with clearing skies and light winds, highs will only be in the upper single digits to low teens. This keeps sub-zero wind chills in play for most of the daylight hours. Cloud cover once again complicates the wind chill forecast for Friday night, with winds veering to the northeast and activating Lake Huron moisture flux. Cloud-bearing layer looks to fall within or slightly cooler than the dendritic growth zone, so scattered snow showers expected with greatest chances near the shoreline. Interior locations (west of I-75) are likely to see clearer skies and thus the coldest temperatures Saturday morning, with wind chills once again flirting with -15 degrees.

The aforementioned mid-level deformation axis defines a sharp, positively tilted trough axis that eventually phases and tilts with the broader geopotential height field through the weekend. Compact PV anomaly anchored to this trough remains west of the Great Lakes as it carves into southern CONUS before lifting along the Atlantic Coast. This supports rapid cyclogenesis along the east coast, but keeps SE Michigan on the eastern flank of strong high pressure (1050mb). Thus not expecting any synoptic systems to impact SE Michigan until the next clipper arrives early next week, bringing our next opportunity for light snow accumulations. Otherwise, the main story will be a modest climb in daytime highs into the low 20s Sunday-early next week with h8 temperatures climbing about 10 C. This will end an extended stretch of over a week where temperatures did not rise above 20 degrees.

MARINE

The Great Lakes remain under broad upper troughing allowing arctic air to hold across the waters. Winds hold from the northwest at 10- 20kts with gusts up to 25kts through Friday. Trough influence keeps lake effect snow showers active though directed at the Canadian waters and southern Ontario. Some areas of freezing spray are possible through this timeframe in the ice-free waters however lack of strong winds prevent any widespread heavy freezing spray from developing. Slowly moderating airmass and the northern edge of Plains high pressure allows for gradually weakening winds falling at or below 20kts for the weekend. A weak clipper arrives late Monday but aside for scattered light snow showers, brings minimal marine impacts. Another high dropping out of the upper Midwest then follows for midweek.

PREV DISCUSSION

Issued at 1243 PM EST Thu Jan 29 2026

AVIATION...

A weak front settles slowly southward across Lower Mi while an equally weak ripple of low pressure slides west to east along it this afternoon and evening. Together they support a minor increase in light snow that becomes capable of MVFR visibility pockets primarily in the 21Z to 03Z timeframe. Ceiling has lower predictability but generally hovers around the MVFR/VFR threshold in and near the frontal zone as it lingers overhead late tonight and until it moves south of the Ohio border Friday morning. Southward passage of the front reduces potential for snow but reinforces arctic air across the region. A weak ridge of surface high pressure follows with a continued disorganized cloud pattern into Friday afternoon.

DTW THRESHOLD PROBABILITIES...

* High for ceiling 5000 feet or less this afternoon and tonight.

DTX WATCHES/WARNINGS/ADVISORIES

MI...Cold Weather Advisory from midnight tonight to 10 AM EST Friday for MIZ047>049-053>055-060>063-068>070.

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