textproduct: Detroit/Pontiac

KEY MESSAGES

- A Cold Weather Advisory remains in effect through Saturday morning with wind chill values dropping to between -15F and -25F.

- Coverage and intensity of lake effect snow showers will decrease during the morning hours with new snow accumulations of less than a quarter inch.

- Confidence continues to rise in widespread accumulating snowfall for Sunday, including the potential for 3+ inches focused south of M- 59.

AVIATION

Moisture along and ahead of a cold front will bring the potential for snow showers at the Detroit terminals the first hour of the taf period. Very dry air associated with surface high pressure will lead to low sky fraction this morning before diurnal heating contributes to stratocumulus development this afternoon. A lowering inversion will then dry the lower column out and lead to SKC tonight.

For DTW...Snow showers will be possible the first hour of the taf period. MVFR development appears likely by the early afternoon.

DTW THRESHOLD PROBABILITIES...

* Medium for ceilings aob 5000 feet this afternoon.

* High for precip type as snow through the TAF period.

PREV DISCUSSION

Issued at 414 AM EST Fri Jan 23 2026

DISCUSSION...

An airmass of Arctic origin spilled across the Great Lakes region overnight, resulting in anomalously cold temperatures and wind chills this morning. 08Z readings were generally in the low to mid single digits (F), but with post-frontal gradient winds holding in the 10-15 knot range, actual wind chill values will drop into the -15F to -20F range as cold air continues to filter in. Based on expected temperature/wind trends through the remaining morning hours, the likelihood to reach Extreme Cold Warning criteria (-25F) in widespread fashion appears low, especially south of I-69. No headline adjustments were made with this morning's forecast, but a few isolated/outlying areas could briefly experience wind chills below the -25F mark. A Cold Weather Advisory remains in effect through Saturday morning, as similar conditions are still expected to repeat tonight into Saturday morning.

For the rest of today, the closed low featuring a sampled 495 dam geopotential height at 500 mb (23.00Z CWPL RAOB), broadens as it ejects ENE across Quebec. This reinforces adjacent positioning of the polar jet for most of today with the 150 knot core residing over southern Lower Michigan. Meanwhile, differential cold advection helps steepen low-level lapse rates while mixing depths hold near the 850 mb level (4 kft AGL). In spite of observed upstream 850 mb temperatures of -37C and -33C at KINL and KMPX, respectively, low- level flow trajectories over Lake Michigan will have a minor moderating effect upon arrival to Southeast Michigan. 850 mb temperatures minimize within the -25C to -30C range locally between 15Z and 21Z, per model data. This translates to high temperatures struggling to get much more than a few degrees above 0F during the daylight hours today. Gradient winds hold from the WNW AOB 15 knots, therefore daytime wind chills should linger in the minus teens for most of the day. Snowfall should become more transient with time and minimal accumulations. SLRs decline with decreasing dendrite quality given the lack of DGZ overlap, therefore wind-blown snow should tend to be more impactful than new accumulations. Tonight will be the coldest night of the week with lows of -10F or colder possible. Fortunately, winds weaken and trend toward calm late tonight as diffuse surface high pressure sets up over southern Lower. Still expect wind chill values to fit squarely within Cold Weather Advisory criteria.

Weak low-level wind field Saturday minimizes opportunities for another round of lake effect snow. Not much in the way of relief from the cold, but the difference between air temperatures and wind chills will be limited as high pressure crosses over Southeast Michigan, eventually flipping light winds easterly.

The next precipitating synoptic system lifts out of the southern Plains early Sunday preceded by an extended ramp of isentropic upglide through the Ohio Valley and Lower Peninsula. This facilitates column moistening and the development of light snowfall, well downstream of the northern and southern stream wave phasing that unfolds over south-central CONUS. The lag in dynamic support until later in the day Sunday suggests less than an inch of snow on the ground heading into Sunday morning, before the better rates arrive during the day with the strongest dynamic influence and deep- layer DGZ intersection. The QPF footprint with this system is relatively narrow where the highest confidence in 3+ inches is focused south of M-59. Further north, and even moreso west, QPF drops off sharply with less than an inch of total accumulation anticipated north of M-46.

MARINE...

The expansion of arctic air in the wake of a cold front will maintain strong overlake instability and a deep mixing layer which will retain breezy conditions. Wind gusts around 25 to 30 knots are expected through the day. Some isolated gust to gales cannot be ruled out across northern Lake Huron this morning, but the gradual expansion of a strong high pressure system will limit gale potential through the day. Gale Warnings have expired, but a Heavy Freezing Spray Warning remains in effect for all of Lake Huron. Additionally, snow squalls remain likely favored through north and north central Lake Huron where low-level convergence is maximized. Rapid reductions in visibilities are likely under any snow squall.

Arctic air holds over the weekend but lighter winds are expected as the aforementioned high pressure system settles over the area. An expansive low pressure system over the eastern US will then clip the southern Great Lakes Sunday, bringing widespread light snow through the day for portions of the southern Great Lakes.

CLIMATE...

The record low max temps for today, January 23rd.

Detroit: 6 Degrees (Set in 1883) Flint: 6 Degrees (Set in 1959) Saginaw: 3 Degrees (Set in 1963)

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)

DTX WATCHES/WARNINGS/ADVISORIES

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

Lake Huron...Heavy Freezing Spray Warning until 6 AM EST Saturday for LHZ361>363- 462>464.

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