textproduct: Detroit/Pontiac

KEY MESSAGES

- Additional light showers at times today, mainly north of I-69.

- Snowfall Sunday with around an inch on the ground by Sunday night.

- Highs could struggle to break above the freezing mark Monday, and possibly Tuesday, with morning wind chills in the single digits.

- Additional opportunities for snowfall Tuesday and Wednesday before precipitation changes over to rain with time on Wednesday.

AVIATION

MVFR ceilings associated with a stratus deck will prevail through bulk of the TAF period as the stalled low pressure over lake Huron maintains the moist west to northwest flow across Michigan. Wind speeds this afternoon will be around 10-15 knots with occasional gusts to around 20 knots. Light snow begins to enter the picture tonight across MBS first where nearby snow showers may eventually reach the Tri-Cities. Lower confidence in start time between the 03Z to 10Z time frame. There is greater confidence for greater snowfall intensity to fill in between 10-12Z and into early afternoon. Lower MVFR visibility restrictions are being forecast with the potential for periods of IFR conditions throughout the morning hours tomorrow. Winds turn more out of the northwest by late tomorrow morning.

For DTW...Potential for light snow increases during the early-mid morning hours Sunday with potential for periods of IFR conditions.

DTW THRESHOLD PROBABILITIES...

* High for ceiling aob 5000 feet through tonight.

* High for ptype of snow tonight and Sunday.

PREV DISCUSSION

Issued at 353 AM EST Sat Feb 21 2026

DISCUSSION...

Lots of moving parts to contend with over the next 48-60 hours, starting with an occluded low stalled over Lake Huron. This has functioned to reinforce the existing surface pressure gradient, sustaining blustery zonal winds. It has also provided a link to an elongated axis of inverted troughing, coincident with a narrow (and shrinking) corridor of low-level moisture. The convergence zone extends well into Manitoba where a broader upstream circulation resides. Expect continued light snow production into portions of Lower Michigan, mainly for the Tri-Cities and Thumb areas. In the absence of significant geopotential height adjustments, this periodic light snowfall should linger through most of the day. Accumulation potential appears limited since temperatures rise back above the freezing mark during the mid-morning hours. For the rest of the forecast area, drier conditions are favored until a shortwave trough digging into the subtropical jet reaches the Mid-Mississippi Valley. Coverage of light snowfall broadens in response late tonight and into Sunday morning.

The stationary low eventually exits on Sunday as central pressure fills in to approximately 1015 mb (from 1003 mb at 06Z today). CVA supports a period of sustained ascent over the region which leads to a period of accumulating light snowfall. Snowfall totals will be highly sensitive to surface-layer fluxes. Colder air tries to filter in as flow veers northwesterly, marked by a drop in 850 mb temperatures to the negative double-digits (Celsius). Uncertainty remains regarding the diurnal curve Sunday given a sharp E-W thermal gradient over Lower Michigan. The colder air should remain over the western half of the state since the Huron low traps the milder airmass later into the day. This leads to a prolonged period of temperatures above freezing Sunday leading to some degree of melting that cuts into total accumulations. Assuming a frozen surface, most locations should end up with 0.5 to 1.5 inches of snowfall by Sunday evening. However, any well-traveled surfaces will be subject to melting should highs rise into the mid, if not upper, 30s. Elevated and grassy surfaces, especially those that accumulate a base coating during the morning hours, possess a higher likelihood for optimal accumulation efficiency. The aforementioned low gets absorbed into a nor'easter Sunday night while the gradient constricts and cold advection strengthens. Decreasing lake ice and increasing mixing depths favor a bit of lake effect snow, especially over The Thumb.

Seasonably chilly Monday and Tuesday as thermal troughing centers over the Great Lakes region. Highs could struggle to break above the freezing mark Monday, and possibly Tuesday, with morning wind chills in the single digits. NNW flow lends some lake effect snow potential off Lake Huron Monday, mainly for Huron County. Synoptic snowfall arrives late Tuesday after a brief period of ridging. A rapidly moving embedded northern stream shortwave phases with the southern jet over the Plains Tuesday, leading to quick cyclogenesis atop the Upper Midwest. The low-levels look to saturate early with weak ascent, before the upper-level divergence maximizes and saturates the full column with a jump in UVVs. Most of the snowfall should occur late Tuesday night and Wednesday morning. Potential exists for precipitation to change over to rain with time on Wednesday as temperatures rise above freezing.

MARINE...

Low pressure remains over Lake Huron with central pressure continuing to rise through the morning as the low fills in. Cyclonic flow remains in place, characterized by north-northeast flow across northern Lake Huron that becomes increasingly westerly inland and toward Lake Erie. The resulting convergence axis will direct lake effect snow over Lake Huron through the day, with potential for intense bursts of snow in banded structures. The low pressure center gradually eases eastward to merge with a coastal Atlantic low Sunday, drawing the convergence axis south while an upper level disturbance slides across the Ohio Valley to expand snow chances south into all marine zones. The Great Lakes then reside in a transition zone between the coastal low and building high pressure over the Plains, which boosts sustained northerly winds to 25-30 knots Sunday night into Monday. This will be the next opportunity for marine headlines as winds and waves become elevated. Very brief period of high pressure builds in Tuesday ahead of the next quick moving clipper system that arrives mid-week.

DTX WATCHES/WARNINGS/ADVISORIES

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