textproduct: Detroit/Pontiac

KEY MESSAGES

- Frigid wind chills tonight falling in the negative single digits. Low teens wind chills Friday afternoon.

- Below normal temperatures persist this weekend and into next week.

- The next chances for light snow will be Friday night and Sunday. Sunday holds a 50% chance to exceed 1 inch.

AVIATION

High pressure extending from Texas to The Northeast reinforces a drier airmass over the terminals this morning. A cold front slowly approaches the area later in the day and into the overnight hours which brings about top-down moistening. Ceilings remain VFR or all sites, with the one exception being MBS which lies on the edge of lake stratocumulus. Southwesterly gradient winds strengthen today, becoming slightly gusty, up to around 20 knots. Ceilings descend to MVFR late tonight or early Saturday morning. A few flurries are possible, but potential will be greater further north. Did TEMPO in light snow at FNT and MBS for the end of the TAF period.

DTW THRESHOLD PROBABILITIES...

* Low for ceiling at or below 5000 ft before 06Z Saturday.

PREV DISCUSSION

Issued at 351 AM EST Fri Dec 5 2025

DISCUSSION...

The 00Z DTX RAOB recorded a PW value of .10", a daily record, which has maintained virtually clear skies overnight under calm to very light winds. This idealistic setup for efficient radiational cooling under snow covered grounds have lead to an anomalously cold start to the morning with temperatures ranging in the single digits across SE MI. Very modest warm air advection this afternoon under southerly flow will have temperatures only warming up into the mid 20s. Winds gusting around 15 mph will maintain wind chills in the teens through the daylight hours. The advent of upper-level clouds will hold overnight temperatures in the upper teens to low 20s overnight.

A weak prefrontal trough and passage of a cold front does bring the chance for some wintry precipitation overnight through Saturday morning, but the weaker forcing within the dry environment precludes any meaningful accumulation. A dusting of snow accumulation will be possible across SE MI, most favorable over the northern third of the cwa (north of M59) where slightly better moisture resides. Given moisture quality issues, the shallow moisture depths will likely reside just shy of the dgz, nearing - 10C. While ice nucleation is still likely with these cooler temperatures, there will be low chance for some periodic freezing drizzle. Forcing along the cold front, projected to move through in the mid morning hours into the early afternoon, can briefly elevate moisture heights back into the dgz and will be capable of producing a quick dusting of snow.

Dry air filters in the wake of the front as the brunt of the polar airmass holds north of the state, allowing temperatures to rise into the low 30s for a high Saturday. Attention will then turn to the next potential accumulating snow event which will derive from a clipper system which is projected to arrive across the Plains into the Midwest late Saturday night before spreading across the Great Lakes region by Sunday morning. System relative isentropic ascent will be maximized through the mid-levels between 700 to 500 mb which will allow for light snow development to overspread across the Ohio Valley into Michigan. A dusting, up to two inches of new accumulation will be possible pending how well the system sustains intensity as it travels into the region.

One possible scenario leading to lesser snow amounts will be the speed at which an arctic high pressure drops down from the plains which will have the ability to hold the better moisture south of the state line as dry air filters in. The latest EPS solution favors this scenario, bringing probabilities to see an inch of snowfall to 15% or less. NBM probabilities which encapsulates a larger set of ensembles holds chances around 30%, a decreasing trend from 12 hours ago. Outside of the northern Thumb which will hold onto lake effect snow chances in the wake of the low pressure, the arctic high will set up over the Great Lakes bringing dry conditions late Sunday into Monday. This also brings well below normal temperatures to start the next week with highs in the 20s and lows in the single digits to lower teens.

MARINE...

Pressure gradient is beginning to tighten early this morning as the next low pressure system starts moving into Ontario with a cold front draped through the Midwest. The cold front will not sweep through until early Saturday which will lead to another round of increased southwesterly winds early this morning through early Saturday. Another round of Small Craft Advisories for Saginaw Bay have been issued as southwesterly winds again increase to around 30 knots. Could see a few gusts to 35 knot gales over central Lake Huron Friday, but should be isolated enough to avoid mentioning gales in the forecast at this point. Guidance did pretty well with the winds the last couple days with both southwest and northwest flow, which lends to increased confidence with this next event.

DTX WATCHES/WARNINGS/ADVISORIES

MI...None. Lake Huron...Small Craft Advisory until 4 AM EST Saturday for LHZ421-422-441.

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