textproduct: Detroit/Pontiac

KEY MESSAGES

- Breezy conditions Monday as a cold front crosses the region in the late morning. Peak gusts are expected to fall in the 30 to 40 MPH range.

- Chances for rain favored towards northern half of the region Monday morning.

AVIATION

Steady 5 to 10 knot southwest wind will carry through bulk of this evening and tonight. VFR skies will start the TAF period as increasing high clouds move in ahead of an approaching cold front. A strong low level jet will bring LLWS concerns tonight before the cold front arrives. An area of showers will then move into MBS toward 09-10Z and then work through southeast Michigan through about 14-15Z. Highest confidence for showers will be across FNT and MBS with less confidence towards the southern metro terminals, so will go with TEMPO groups to the north and maintain PROB30 groups for rain showers to the south. MVFR ceilings will quickly fill in around 12-13Z for a relatively short period of time with the frontal passage before clouds decrease in post frontal conditions into the early afternoon. Gusty west winds will then develop Monday afternoon with cold advection and a tight pressure gradient supporting gusts of 30 knot. Gusts then ease during the evening under clear skies.

For DTW/D21 Convection...No thunderstorms today through Monday.

DTW THRESHOLD PROBABILITIES...

* High for ceiling 5000 feet by 10-12Z Sunday morning. Low for Monday afternoon.

* Low to moderate for crosswind thresholds Monday afternoon.

PREV DISCUSSION

Issued at 348 PM EST Sun Nov 2 2025

DISCUSSION...

The exit region of a strong 160 knot jet racing along the US/Canada border this afternoon will reach the Great Lakes tonight bringing the next chance of precipitation Monday morning and gusty winds into the afternoon. Models have deviated little in the previous few runs having a stacked low over northern Ontario drawing some lead energy from the jet northward before the nose of the jet barrels into lower MI. This will push the southern extension of the cold front through SE MI late Monday morning with a very narrow warm sector just preceding it. This setup will offer a brief window of rain over the area mainly between 09-15Z. Main update with this package was to extend slight chance pops southward to the border giving credit to a ribbon of strong fgen, upper level support, and strong low level jet. We've seen it too many times where the lead edge of the theta e gradient and fgen is able to generate light showers even under the backdrop of drier air under the ridge.

A strong, but weakening, 40 knot low level jet will pass over the area in advance of the system tonight but will have difficulties mixing to the surface overnight. Behind the cold front, mixing depths increase which will tap into some of the increase westerly flow with 850mb winds around 35 knots. Local probabilistic graphics show a low chance for surface gusts to exceed 35 mph and national hires probs mostly stay below 35 mph as well. Could see a situation where the initial pop of wind could see some higher gusts around 35- 40 mph before settling more around 30-35 mph through the afternoon hours. Best potential for higher gusts remains across the northern Thumb with the increased winds off Saginaw Bay coming ashore.

Longwave pattern flattens out locally mid week with a shortwave ridge sliding over the region bringing quiet weather on Tuesday. The low amplitude and progressive longwave pattern continues through the remainder of the forecast though with the next trough coming early Wednesday. Outside of a weaker jet around 130 knots driving the system, the overall look to the pattern is similar to tonight/Monday with the low passing to the north and weaker trough/cold front sweeping through lower MI presenting a chance for rain. It does appear to be shifted a little south of tonight's system offering a better chance for precipitation. After another ridge on Thursday a pair of systems will look to target the area Friday and Sunday.

MARINE...

A diffuse high pressure system will continue to hold across the Great Lakes through the afternoon and early evening hours which will maintain lighter winds for most of the region. Unsettled conditions will quickly move in tonight and will last through most of the day tomorrow in association with an approaching cold front. Southwest flow will ramp up tonight, initially across northern Lake Huron, before increasing through the Saginaw Bay and central Lake Huron into the early morning hours. Sustained wind speeds around 25 to 30 knots are expected with gust potential to 35 knot gales. Wind direction will veer west-northwest tomorrow morning and afternoon in the wake of the front, where improved mixing depths will sustain gale potential through the day. The favorable fetch across north and north-central Lake Huron brings higher chances for gusts to peak around 40 knots after the passage of the cold front. Widespread showers are expected with the front through the morning. A Gale Warning and Small Craft Advisories are in effect.

A ridge of high pressure will build in Tuesday, bringing respite from unsettled conditions. A second low pressure system is expected to move across northern lower Michigan by Wednesday , bringing back elevated winds and gusts through the midweek period. Gusts to 30 knots will be possible with this system.

DTX WATCHES/WARNINGS/ADVISORIES

MI...None. Lake Huron...Small Craft Advisory from 10 PM this evening to 10 PM EST Monday for LHZ442-443.

Gale Warning until 10 PM EST Monday for LHZ361>363-421-441-462>464.

Gale Warning until 10 AM EST Monday for LHZ422.

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

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

Low Water Advisory from 7 AM to 10 PM EST Monday for LEZ444.