textproduct: Detroit/Pontiac

KEY MESSAGES

- Mild tonight and Friday. Widespread rain showers tonight.

- Windy Friday, gusts 35 to 45 MPH possible.

- Rain and wet snow Saturday transitions to snow showers Saturday night and Sunday. Snow squalls are possible Sunday.

DISCUSSION

The mid level short wave feature now over the central US will lift across the northern Great Lakes Friday, while the associated sfc low tracks across the straits region early Fri morning. There will be an impressive wind field through a deep layer in advance of this wave, with a 60-70 knot 925mb low level wind maximum forecast to lift across Se Mi overnight. This will make for efficient moisture transport into Lower Mi ahead of the associated sfc cold front. Ongoing Gulf moisture influx is already underway across the southern and mid Mississippi Valley, with the 12z model suite in good general agreement of precipitable water values rising to 1.1 to 1.3 inches across Se Mi overnight. The initial surge in mid level theta e advection will occur this evening, resulting in a region of light rain progressing northward across the area. Persistent isentropic ascent and weak elevated instability within the moist axis will sustain occasional showers through the night, with some isolated thunderstorms possible. A line of shallow convection is also forecast to accompany the sfc cold front across Se Mi in the 15Z to 18Z time frame Friday.

The suite of ensemble members indicate some variance on potential surface gusts tonight into Friday morning, which results in the difference between advisory criteria gusts (45M PH) or sub advisory winds. This uncertainty is related to boundary layer stability concerns. Southerly flow will drive temperatures well into the 50s tonight. Given current temps across the Ohio Vally, the potential for a few locals to break 60 Fri morning prior to fropa can not be ruled out. Even with this degree of warming in the boundary layer, mixing depths within the prefrontal warm sector will be quite limited, supportive of holding wind gusts below 45 MPH. There will be shallow frontogenetical forcing along the sfc front Friday, which leads to an increased risk of a second period of stronger gusts within the immediate post frontal subsidence region as low level lapse quickly steepening with the onset of cold air advection. This is the period of concern for potential advisory level wind gusts. The potential brevity of the ideal mixing profile corresponding with the axis of strong winds argues holding off on the issuance of a wind advisory for Friday this forecast cycle.

Amplification of an upper wave in the lee of the Canadian Rockies Friday is forecast to evolved into a deep closed upper low over the western Great Lakes Saturday. Associated surface cyclogenesis is forecast across the eastern Great Lakes. A deep layer moist plume continues to be shown by model solutions to be shunted east of the region, with a continued trend toward non phasing with a southern stream wave. An initial influx of positive mid level vorticity advection across Se Mi Saturday will support a good chance for precipitation. The thermal profile across the forecast area gives higher chances for rain across the eastern half of the forecast area, with wet snow favored across the west. The upper low will move across Lower Mi and Lake Huron Saturday night and Sunday. The combination of wrap around moisture, a mid level cold pool and lake enhancement will set the stage for occasional snow showers, some of which may be briefly intense.

MARINE

A strong low pressure system remains on track to traverse from the Central Plains into the northern Great Lakes through tomorrow morning. The pressure gradient will quickly strengthen with the arrival of the low, which will result in sustained wind speeds of 20 to 30 knots late tonight through tomorrow morning. Despite the very stable low level profiles, the strength of the pressure gradient will likely afford a window for some low-end gales favored across southern and central Lake Huron, where Gale Warnings remain in place.

A strong cold front will then move across the Great Lakes as the low pressure system departs, which will veer wind direction from south to northwest. Cold air behind the front will rapidly decrease over lake stability and will boost mixing depths, bringing higher confidence for gust to gales leading into the evening hours. Immediately along and behind the front, a quick pop of an isolated gust to high-end gales around 45 knots will be likely in the afternoon across Lake Huron. A change to note for this afternoon forecast is the addition of a Gale Warning for northern Lake Huron as confidence regarding gust to gales has increased behind the cold front.

Small Craft Advisories remain in place for all ice free nearshore zones, where gusts around 30 knots will be likely through tomorrow. The exception will be along and immediately behind the aforementioned cold front, where a quick pop to gust to gales wil be likely. Last, widespread rain will accompany the low pressure system tonight and tomorrow. High pressure rapidly builds in behind the cold front, diminishing stronger winds leading into Saturday.

HYDROLOGY

Occasional rain showers will affect the entire region tonight into Friday morning. There is moderate to high probabilities for a quarter inch of rain, with lower probabilities for a half inch to inch. The Saginaw Valley region has a little higher total QPF probabilities, with low chances for total rain to exceed one inch. The rainfall amounts are not expected to be enough to produce flooding.

CLIMATE

The record high temps for Friday, January 9th.

Detroit: 55 Degrees (Set in 1949) Flint: 54 Degrees (Set in 1939) Saginaw: 54 Degrees (Set in 1939)

PREV DISCUSSION

Issued at 1232 PM EST Thu Jan 8 2026

AVIATION...

Strong warm advection precedes the arrival of low pressure tracking into the western Great Lakes late this evening, with a powerful low- level wind field passing through tonight into Friday. A degree of stability will be maintained below the low-level inversion at 2 to 3 kft, keeping the higher magnitude of wind aloft. However, southerly wind atop this layer increases from 40-45 kt this afternoon to 50-60 kt overnight. Despite some gustiness reaching the boundary layer, elected to include LLWS mention in the TAF overnight. Showers associated with the low arrive from the SW late this evening and overnight ahead of the cold front. There will be a chance for thunder with the initial showers around midnight but left TS out of TAF for now. MVFR conditions will gradually spread eastward during this period with some pockets of IFR possible overnight. The cold front then passes through the region midday Friday, accompanied by a line of showers and a wind shift from S to SW to NW. Gusts are likely to near or exceed 30 kt through the early afternoon, especially along the front.

For DTW... Arrival of rain showers is anticipated between 03Z and 05Z tonight with MVFR working in during the early morning hours. Relatively low confidence exists for IFR Friday morning. Core of 50+ kt wind aloft will be centered between 03Z and 12Z Friday. Shift to SW (220 deg) wind direction around 15Z then W (260 deg) around 18Z brings potential to exceed crosswind thresholds.

DTW THRESHOLD PROBABILITIES...

* High for ceiling at or below 5000 feet after 03Z tonight.

* Low for thunderstorms late this evening.

* Moderate for exceeding crosswind threshold between 15Z and 20Z Friday.

DTX WATCHES/WARNINGS/ADVISORIES

MI...None. Lake Huron...Gale Warning from noon to 7 PM EST Friday for LHZ361.

Gale Warning from midnight tonight to 7 PM EST Friday for LHZ362- 363-462-463.

Small Craft Advisory from 8 PM this evening to 7 PM EST Friday for LHZ421-441>443.

Lake St Clair...Small Craft Advisory from 10 PM this evening to 7 PM EST Friday for LCZ460.

Michigan waters of Lake Erie...Small Craft Advisory from 10 PM this evening to 7 PM EST Friday for LEZ444.