textproduct: Detroit/Pontiac

KEY MESSAGES

- Cold overnight. Minimum wind chill early tomorrow morning ranging from 0 to 5 degrees.

- Accumulating snow late Tuesday through Wednesday morning. Snow totals ranging from one half to 2 inches, with highest amounts across the Saginaw valley and northern thumb.

- Seasonable temperatures through the midweek period.

DISCUSSION

Subtle backing of low-level winds to the northwest will retain cold air across Michigan with 850 temperatures down to -15C. This will bring cold overnight temperatures with lows in the single digits across the Thumb and low teens elsewhere. There is a low possibility for development of a snow band just offshore to briefly glance the tip of the Thumb in Huron county as these winds back, which may amount to light accumulations before continued backing pushes any banding features back offshore.

Dry conditions for the bulk of the day as highs return to normal values in the 30s. Attention will turn to a clipper system that will enter SE MI tomorrow night. Initially, some light returns will be possible late tomorrow night favored across the Tri-Cities and northern Thumb along an elevated warm front as subtle isentropic ascent turns more favorable. Continued progression of the clipper system will then drive a cold front across SE MI through early Wednesday morning, which will result in the better snow accumulation potential. The main forcing will be found along the elevated frontal boundary with most intense lift between 800-400 mb with enhancement from the associated mid-level wave. This system will be quick hitting from northwest to southeast between roughly 23Z to 06Z Wed, limiting snow accumulation potential to around an inch or less. There may be a brief 30-60 min of enhanced snowfall rates, given mesoscale banding aligned along the elevated front. This can account for a very quick half-inch to inch of snow accumulation, outside of the broader ascent/lighter snowfall.

A lull in snowfall is expected in the wake of the clipper system, however, the lagged surface caa will increase through the morning hours as a secondary mid-level wave traverses over SE MI. Lake enhanced moisture will move inland given large land/lake delta T while overland thermodynamics turn more favorable noting uptick in surface CAPE and negative 0-2km theta-e lapse rates. This will bring snow shower potential with the possibility for embedded heavier snow showers or convective snow squalls, most favorable M59 north. An additional half-inch to an inch of new accumulation will be possible under any heavier snow showers. This activity leading to snow accumulation ends through the afternoon once mid-level subsidence increases, shrinking convective depths. The continuation of west flow with the subsidence does bring the chance for flurries for the remainder of the day until low-level streamlines upstream turn more southerly by late Wednesday night.

Thursday morning has been a time of interest regarding snowfall potential across southern Michigan but has been contingent on where a baroclinic zone aligns across the Ohio Valley and where precipitation from overrunning will set up. The vast majority of deterministic and ensembles have shifted the precipitation shield south of the state line owing to less amplification of the upstream troughing across the Plains, which in turn holds the better moisture and isentropic ascent to the south. There is still a subset of ensembles (<25%) that clip southern Michigan with snow which is highlighted in the latest NBM PoPs, with retains the chance to see snow. Otherwise, temperatures hold right around the average through the midweek period with highs in the low 30s and lows in the 20s, with increasing temperature trends to end the week with highs in the 40s.

MARINE

Gusty northwest winds subside this evening as high pressure builds in from the west. Sustained winds drop below 10 knots overnight, reducing moisture flux off of Lake Huron and bringing and end to snow showers. High pressure influence will be short-lived as the next clipper system quickly moves toward the Great Lakes Tuesday afternoon, shifting winds to the south. A strong low level jet (50- 55 knots) accompanies this system, although will be anchored to warm advection that leads to stability across the cold/ice covered waters. Guidance keeps winds elevated, especially with the low level jet max coming through after peak diurnal mixing. These factors limit confidence in gusts being able to exceed 30 knots. Much higher confidence in the snow potential with this system, with potential for rates to exceed a half inch per hour Tuesday evening. Winds veer to the west with the passage of a cold front early Wednesday morning, which will subside through the day as high pressure returns Wednesday night. Forecast confidence decreases into the late week period as the next low tracks across the Ohio Valley, but with variability in its exact track and impacts to the Great Lakes region.

PREV DISCUSSION

Issued at 1240 PM EST Mon Feb 23 2026

AVIATION...

High pressure building from the Midwest into the Great Lakes has increasingly dry northerly flow ahead of it across Lower Mi. The dry air is inbound on NW wind gusting in the 20 kt range and is facilitating breaks in the stratocu in between streamers of flurries and MVFR ceiling. The flurries are the first to decrease during the afternoon followed by a greater cloud decrease after peak daytime instability later in the day. The low cloud component remains clear tonight as the surface ridge builds overhead followed by high clouds late tonight. It does appear Lake Michigan stays active with lower clouds and this will be monitored for inland advancement as cloud layer wind backs SW Tuesday morning. VFR is otherwise expected across the SE Mi terminal corridor during the morning and early afternoon.

For DTW... Flurries end first early this afternoon followed by a decreasing cloud trend toward evening. MVFR ceiling grinds up to VFR below 5000 ft late in the day before breaking up in coverage after sunset. NW wind gusting in the 20 kt range also drops off as peak daytime instability decreases toward sunset.

DTW THRESHOLD PROBABILITIES...

* High for ceiling at or below 5000 feet this afternoon.

* High for precipitation type as snow.

DTX WATCHES/WARNINGS/ADVISORIES

MI...None. Lake Huron...Heavy Freezing Spray Warning until 10 PM EST this evening for LHZ361-362.

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