textproduct: Detroit/Pontiac

KEY MESSAGES

- A good chance of rain Tuesday.

- Accumulating snow Wednesday and Wednesday night as arctic air moves into the region.

- Much colder late this week and into next weekend. Minimum morning wind chill around zero degrees.

- Periodic chances for snow will exist Friday through the weekend.

AVIATION

Aggressive surge of dry air this morning has dislodged much of the stratus deck that lingered across the airspace overnight. Lead edge of the dry air has yet to reach MBS, but is on track to reach the terminal around 12z. Observations have been more aggressive with the clearing than models, so do think MBS will see some scattering through the morning. Diurnal mixing then restablishes the cloud deck by late morning. Outside of MBS, VFR conditions persist through the TAF period. High pressure over SE CONUS ensures prevailing southwest flow. Breezy conditions are expected with gusts around 25 knots until this evening. Thickening mid and high cloud fill in this evening in advance of the next clipper system which tracks toward northern Lower Michigan Tuesday.

DTW THRESHOLD PROBABILITIES...

* Low for cigs aob 5000 feet through the TAF period.

PREV DISCUSSION

Issued at 401 AM EST Mon Jan 12 2026

DISCUSSION...

Weak clipper system glancing across the state early this morning within the background of modest low-mid level warm air advection. This brief window of ascent encountering a very dry profile overall, lending to a high coverage of virga as associated mid level cloud increases coverage. A few flurries or brief light snow showers still plausible yet this morning across mainly the thumb. Otherwise, weakly confluent mid level northwest flow atop a warming thermal profile sustains a high degree of stability and ensures benign conditions over the next 24 hours. Moderating thermal profile boosted by a firm southwest gradient, with some gustiness up to 30 mph. Late day highs arriving in the mid to upper 30s. Sustained waa as high cloud thickens will maintain milder conditions overnight.

Southern extension of a more dynamic mid level wave of north pacific origin arrives Tuesday. Improvement in moisture quality and depth as isentropic ascent peaks along the lead edge of the inbound height fall gradient will provide the greatest potential for precipitation production starting early in the day north and expanding southeast into the afternoon. Assessment of sounding data and projection of low level thermal trends point to mainly rain as the precipitation type, with limited potential for some melting snow to mix in should precip onset arrive early enough in the day across the north. Mildest conditions of the forecast period as daylight 850 mb temps peak at 4-5C, translating into highs of upper 30s to mid 40s. Once again, some gustiness of sustained southwest wind up to 30 mph. An initial weaker phase of cold air advection emerges Tuesday night as mid level northwest flow deepens with time. Lingering lower end shower potential overnight, as additional pva works to capitalize on a moistening cyclonic flow and steeper lapse rates.

A more sizable pattern shift will develop for the late week period and continue through next weekend, as high amplitude longwave troughing takes residence across much of the conus downstream of an anomalously strong west coast upper ridge. The net result will be an extended stretch of below average temperatures, with periodic snowfall chances within a very active pattern. Southward propagating arctic lobe to lead this transition Wednesday and Wed night. Notable 24 hour drop in temperature of around 20 degrees during this time under pronounced cold air advection. High probability of snow as a focused area of upward vertical motion tied to the frontal zone and trailing mid level vort max engage a deeper layer of supersaturation with respect to ice inside the dgz. Deep northerly flow within the immediate wake will then provide a lake response off lake Huron overnight. Magnitude and duration of any lake effect uncertain at this stage, as the drying mid level influence by the inbound arctic environment may place a lower ceiling on prospective overlake equilibrium heights.

Arctic air entrenched to finish the week. Minimum wind chill both Thu and Fri mornings around zero degrees. Additional shortwave energy projected to dive southeast into the mean trough Friday into the weekend. Some consolidation of pv as the height falls gradually spill into the great lakes will bring unsettled conditions at times, but with a high degree of uncertainty as to timing and magnitude of possible snowfall episodes. Forecast will continue to highlight a broad chance for snow throughout this period at this stage.

MARINE...

A somewhat active pattern continues for the next several days as a weak trough moves through northern Lake Huron. This has led to a slight uptick in gradient winds (near 25 knots) early this morning, backing southwesterly by sunrise. Waves remain elevated for the nearshore waters along the tip of The Thumb, thus Small Craft Advisories remain in effect until this evening. Modest flow persists Tuesday and turns southerly ahead of the next clipper system. This could lead to extensions and/or expansions of Small Craft Advisories for portions of the southern Lake Huron nearshores, but gusts should hold below gales across the waterways. The low then slowly pivots through the region Tuesday night into Wednesday, eventually forcing a cold frontal passage. Potential exists for a period of post- frontal gales late Wednesday.

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.