textproduct: Detroit/Pontiac

KEY MESSAGES

- Cold weather will persist through the weekend. Wind chills are forecast to fluctuate between the single digits and teens above zero.

- The next chance of light snow up to around an inch will come Saturday afternoon and evening, with highest chances across the Saginaw Valley and northern Thumb.

- The potential exists for accumulating snowfall over 1 inch Sunday night into Monday morning. The highest likelihood for impacts to the Monday morning commute is currently located north of M-59.

AVIATION

Stretch of dry low level conditions entrenched tonight and Saturday morning, as weak surface ridging maintains control. This ensures VFR conditions as high cloud gradually thickens and lowers with time. Winds remain modest from a west-northwest direction during this time. Weak clipper system lifting across the northern great lakes will bring a chance of light snow Saturday afternoon and evening. This will lead to a period of lower VFR to MVFR ceiling height, while offering a window for possible MVFR/brief IFR visibility in falling snow.

For DTW...Brief window for possible light snow shower development Saturday afternoon and early evening.

DTW THRESHOLD PROBABILITIES...

* High for ceiling aob 5000 feet through mid afternoon, then low late today.

PREV DISCUSSION

Issued at 332 PM EST Fri Jan 2 2026

DISCUSSION...

Surge of low level dry air earlier this afternoon has been successful in scattering out the lake effect stratus plume, leading to sunny skies for most that will persist through the remaining daylight hours. Temperatures currently in the low 20s will fall back into the teens overnight, with most of the cooling occurring before midnight as thickening mid-level cloud slows radiative cooling.

Active stretch of weather continues this weekend-first half of next week as the Great Lakes remain in the favored storm track of the shortwave train. The first of these clippers glances across northern lower Michigan latter half of Saturday, but struggles on the QPF front as there is quite a bit of low level dry air to contend with. Disjointed forcing, including a broad footprint of moist isentropic ascent and a more concentrated region of left exit dynamics to the north, support a period of light snow Saturday afternoon-evening. Overall QPF is lean, aob 0.05", but models have trended a few degrees cooler to sustain a deeper saturated DGZ (roughly 5.0-7.0 kft) layer. We have seen over the past few days just how efficient snow production can be with a saturated -12 to -18 C layer, so not ruling out an inch or so of dry/fluffy snow (generally north of I- 69). Areas to the south see closer to a dusting by late Saturday night.

850mb temperatures between now and Saturday night fluctuate by about 5 degrees in either direction as these disturbances briefly perturb the existing baroclinic zone. Limited residence time of any single thermal pattern limits influence to surface temperatures, with highs Saturday and Sunday a few degrees warmer than today: in the mid- upper 20s and overnight lows in the teens.

By Sunday, the upstream height field begins to flatten as the next wave traverses across CONUS. This wave will reach SE Michigan early Monday morning, creating another glancing opportunity for accumulating snow. Pacific origins of this wave afford a deeper layer of column moisture than the Saturday night wave, although there is still a signal for a low level dry layer (e.g. 12z NAM). Whatever moisture does exist will act to engage the elevated warm front as it tracks from Minnesota into SE Michigan early Monday morning. Steepening mid level lapse rates with this system could produce a narrow FGEN band of higher intensity snowfall rates during the Monday morning commute, as depicted in the 12z ECMWF. Accumulations above an inch are favored north of M-59, as the track of the height fall center is right across northern Michigan.

Deamplification of the height field dislodges the prolonged northwest flow regime to the west and eventually southwest, leading to a substantial period of warm advection through the early half of next week. A warming trend ensues with temperatures climbing into the 30s Monday and 40s Tuesday onward. The height field remains open to additional perturbations through the week, but the warming temperatures introduce uncertainty in precipitation type.

MARINE...

Winds begin to slowly decrease tonight as surface high pressure over the Plains attempts to build into the Great Lakes. Its full expansion overhead is delayed by a weaker clipper riding over the top of it into the northern/central Great Lakes Saturday. Aside from widespread light snow, gradient remains fairly diffuse keeping trailing NW winds aob 25kts late Saturday. Aforementioned high then drifts east over the Great Lakes/Ohio Valley Sunday supporting light (<15kt) winds and dry weather to close out the weekend. Another weak low coming out of the central Plains quickly follows for Monday. Similar to Saturday, it brings widespread light snow but doesn't significantly tighten the local pressure gradient supporting only 25kt or less (SSW) winds.

DTX WATCHES/WARNINGS/ADVISORIES

MI...None. Lake Huron...Small Craft Advisory until 10 PM EST this evening for LHZ421-441.

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