textproduct: Detroit/Pontiac

KEY MESSAGES

- A Cold Weather Advisory remains in effect until 10 AM this morning for wind chill values between -15F and -25F.

- Dry conditions today give way to accumulating snowfall late tonight and into Sunday.

- Highly variable snowfall totals expected by Sunday night with 5-6 inches possible for Monroe and Wayne counties, 2-4 inches for the rest of Metro Detroit, and less than an inch north of M-46.

- Very cold conditions continue next week with addition Cold Weather Advisories possible.

DISCUSSION

Very cold start today across Southeast Michigan, and for much of CONUS, as clear overnight skies lie atop a bona fide arctic airmass. This has led to initial readings well below 0F, but since gradient winds are weak (predominantly AOB 5 knots) the difference between air temperatures and wind chill values has mostly been minimal. The Cold Weather Advisory should be allowed to expire by 10 AM as wind chills increase above -15F for the rest of the day. Gradual thermal moderation is already underway within the column, marked by 850 mb temperatures warming from -27C (per 24.00Z KDTX RAOB), to the minus teens (Celsius) by this afternoon. This translates to a marginally warmer day, with daytime highs in the upper single digits, in spite of increasing cloud cover. Mesoscale 1043 mb surface ridge dislodges from southwest Lower Michigan later today and migrates eastward, eventually flipping light winds easterly by this evening.

Continuing to monitor the next opportunity for accumulating snowfall late tonight into Sunday as highly amplified northern and southern stream troughing phase over the southern Plains, before the composite wave ejects into The Northeast by Monday. Local isentropic surfaces steepen and moisten with time as the ThetaE ridge lifts out of the Ohio Valley and into the Lower Peninsula tonight. Light snow begins to spread north of the Michigan/Ohio border sometime between 03Z and 06Z Sunday, well downstream of the actual wave features. The more substantial CVA should still be west of the Mississippi by 12Z Sunday. Given the lack of more meaningful dynamics, initial overnight accumulations (south of I-94) should hold below an inch. The moderate to briefly heavy snowfall rates are not expected until Sunday afternoon, after the lead VortMax clips the southeast edge of the CWA.

As expected with a narrowing time horizon, consensus model data has sharpened wrt the QPF gradient. Latest deterministic, ensemble, and ML guidance show agreement in the expected range of QPF. Areas south of I-94 will likely get between 0.20 and 0.40 inches of liquid equivalent, while the sharp gradient with northwest extent keeps total QPF to around a few hundredths across the Tri-Cities. Regarding snow-related headlines, opted to hold off on an advisory (or watch/warning for Monroe or Wayne Counties) tonight to allow an additional cycle of model data. At the very least, an Advisory will likely be needed for most counties across the southern half of the forecast area where forecast soundings maintain deep saturation through the DGZ. The main limiting factor will be the lack of stronger ascent which keeps average totals in the 2-4 inch range, but decreases sharply north of I-69. The exceptions will be over Monroe and Wayne counties where vertical velocities could produce rates on the order of a half inch per hour. This leads to non-zero potential in approaching Warning criteria, but the latest SLR trends closer to 15-1 and few 7+ inch solutions preclude a Watch. Some uncertainty exists with how long snowfall continues Sunday night, and the extent to which post-event lake effect impinges on the forecast area. Another quarter to half inch is possible late Sunday into Monday.

Daily lake effect snowfall chances in-play for much of next week as colder than normal conditions persist. Several reinforcing shots of arctic air and supporting disturbances aloft offer additional opportunities for wind chills dropping below -15F, therefore future Cold Weather Advisories may be warranted. Daytime highs are capped in the teens during the next 7 days.

MARINE

The maintenance of a heavy lake effect snow band will persist across north to north central Lake Huron through the afternoon as low-level convergence persists within a corridor of unstable conditions. A strong high pressure system to then settle in across the Great Lakes though the day. This will bring a period of lighter winds through the weekend.

Across the southern Great Lakes, light snow will begin to expand across the region through Sunday as an expansive low pressure system arrives across the Appalachia region. The departure of this low pressure system into the western Atlantic will reinforce arctic air across the Great Lakes, which will increase wind speeds through the early and midweek period.

CLIMATE

The record low min temps for Saturday, January 24th.

Detroit: -13 Degrees (Set in 1963) Flint: -13 Degrees (Set in 1963) Saginaw: -13 Degrees (Set in 1963)

The record low max temps for Saturday, January 24th.

Detroit: 4 Degrees (Set in 1963) Flint: 5 Degrees (Set in 1963) Saginaw: 8 Degrees (Set in 1961)

PREV DISCUSSION

Issued at 1112 PM EST Fri Jan 23 2026

AVIATION...

VFR conditions prevail under mostly clear skies as dry air dominates the local environment. Winds out of the northwest at 5-10 knots will carry through the Saturday morning hours. Main item for Saturday will be the increasing coverage of high clouds expanding northward associated with the next winter system. Snowfall expected to start shortly after 06Z Sunday across Lower Michigan.

DTW THRESHOLD PROBABILITIES...

* Medium for ceilings aob 5,000 feet early Sunday morning.

DTX WATCHES/WARNINGS/ADVISORIES

MI...Cold Weather Advisory until 10 AM EST this morning for MIZ047>049- 053>055-060>063-068>070-075-076-082-083.

Lake Huron...Heavy Freezing Spray Warning until 5 AM EST early this morning for LHZ361>363-462>464.

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