textproduct: Detroit/Pontiac

KEY MESSAGES

- Breezy and mild today with a slight chance of wintry mix in the morning followed by scattered light rain showers.

- Snow showers Wednesday and Wednesday night as arctic air moves into the region. Accumulations between a dusting and 1 inch for most locations, with 3 to 4 inches possible along the Lake Huron shoreline of Huron county.

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

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

AVIATION

A clipper system tracks across Ontario today, drawing moisture into the airspace that equates to a blanket of mid cloud and scattered shower activity between roughly 18-22z this afternoon. Prob30 groups were added to all terminals to account for these showers, although restrictions look to be minimal. The tighter pressure gradient around the low establishes gusty southwest flow, with potential for gusts to reach 30 knots this afternoon. Eastward progression of the low then supports a veering trend to the wind field tonight as winds become westerly. More impactful conditions arrive early Wednesday morning and carry beyond the TAF period as a strong cold front dives south across the airspace. A sharp wind shift to the northwest, gusty winds, and snow showers all accompany this fropa Wednesday morning. Drier nature of this arctic front leaves questions about snow shower coverage and intensity to be worked out in later updates, but did include general fropa timing with this update.

For DTW... a strong cold front reaches DTW between 10z-13z Wednesday morning, marked by snow shower activity and an abrupt shift to northwest flow. Snow will be greatest in intensity and coverage along the front, although light snow showers may continue through the morning. Breezy northwest winds develop behind the front, with gusts generally holding below 30 knots to limit crosswind concerns at this time.

DTW THRESHOLD PROBABILITIES...

* Low for cigs aob 5000 feet today, medium tonight.

* High for precipitation type of rain this afternoon. High for snow after 06Z Wednesday morning.

PREV DISCUSSION

Issued at 357 AM EST Tue Jan 13 2026

DISCUSSION...

Firm southwest low level gradient evident immediately downstream of an inbound clipper system will remain the catalyst for ongoing warm air advection this morning. The inbound thermal ridge /+4C 850 mb temps/ will mark the warmest conditions noted this entire forecast period, effectively leading to a daylight peak in temperatures of around 40 degrees many locations. Narrow wing of heightened moist isentropic ascent flanking an initial weak period of height falls will maintain a chance of light precipitation production today. Marginal wet bulb temps may initially afford a few melting snowflakes with any activity across the north this morning, but otherwise ptype remains rain with a higher probability existing with northward extent. Shallow mixed layer within this environment, but sufficient to engage the elevated wind field just off the surface and support some gustiness into the 30 to 35 mph range. Some spotty shower activity plausible early tonight, as moisture depth improves within an initial period of weak cold air advection tied the eastward ejecting clipper.

Focus shifts to the inbound arctic front set to track across the area between 09z and 15z Wednesday morning. Increasing snow shower potential from north to south during this time, with a peak in forcing along the advancing convergence axis drawing upon steepening lapse rates and supportive moisture depth. Secondary window for snow shower development Wednesday afternoon tied to the southward ejecting mid level circulation. Moisture quality lacks overall given the arctic origin, but favorable microphysics will exist for a time as the moist layer takes residence at a deeper layer within the dgz and the magnitude of the advective process removes stability concerns. Forecast maintains general accumulation potential from a dusting to around an inch most locations through the afternoon. Steady column drying as the arctic plume takes greater influence will favor drier conditions by evening. Eastern thumb the exception, as cold north-northwest flow over the long lake Huron fetch elicits a lake response with a concerted focus along the lake aggregate trough. The overall scale, vigor and longevity of activity carries greater uncertainty owing to sensitivity to proper projection of wind trajectory and influence of the drying arctic profile with time. Eastern Huron county most susceptible to persistent, potentially higher intensity lake bands, yielding a smaller footprint of variable accumulation amounts perhaps in excess of 3 inches near the shoreline by early Thursday morning. The downward spiral in temperatures means sub-zero wind chill most locations by Thursday morning.

Arctic cold with dry conditions in deep northwest flow Thursday. Temperatures briefly moderate Friday as the first in series of clipper systems lifts through the region. Combination of warm air advection and dcva with the passing wave brings a high likelihood of snow with some accumulation throughout the Friday period. Trailing shortwave energy will work to carve out a broader mid level trough for the upcoming weekend. This pattern will remain conducive to periodic snowfall chances. Another intrusion of arctic air fortifies a longer stretch of well below average temperatures lasting into early next week.

MARINE...

South-southwesterly gradient winds increase again today with the approach of the next low pressure system into Ontario. A new set of Small Craft Advisories were issued though the evening hours. 35-50 knot flow moves into the lowest 3 kft, but gusts should be held in- check by marginally sufficient lower column stability. Still, cannot rule out a few isolated gale-force gusts this afternoon, mainly over the southern half of Lake Huron. The low ejects into Quebec by Wednesday morning which forces a rather potent cold front across the central Great Lakes. Potential exists for brief marginal post- frontal gales on Wednesday with the ensuing cold advection, but since the low-level wind field should be weakened and displaced further south, no Gale Watch was issued. Extensions and/or additional Small Craft Advisories will likely be required Wednesday. Winds speeds steadily decrease Thursday with a passing surface ridge axis, then flip southerly by Friday ahead of the next clipper system.

DTX WATCHES/WARNINGS/ADVISORIES

MI...None. Lake Huron...Small Craft Advisory from 10 AM this morning to 10 PM EST this evening for LHZ442-443.

Small Craft Advisory from 10 AM this morning to 5 AM EST Wednesday for LHZ421-441.

Lake St Clair...Small Craft Advisory from 10 AM this morning to 10 PM EST this evening for LCZ460.

Michigan waters of Lake Erie...Small Craft Advisory from 10 AM this morning to 10 PM EST this evening for LEZ444.