textproduct: Detroit/Pontiac

KEY MESSAGES

- Mild temperatures continue into Thursday with highs in the 70s. These high temperatures are 10 to 15 degrees above normal.

- There is a chance of showers and an isolated thundestorms Thursday afternoon and Thursday night.

- Dry and continued mild this weekend.

DISCUSSION

A jet exit region and upper level confluent flow will migrate towards the Canadian Maritimes during the next 36 hours. The 1000- 500mb ridge will amplify over Lower Michigan, dampening the effects of a deep shortwave trough lifting out of the Northern Plains to James Bay. Precipitation free conditions can be expected for the remainder of today ahead of the cold front along with temperatures some 15 degrees above normal. A relatively dry cold front draped from the shortwave will push across the forecast area between 18z Thu - 01z Fri.

Relative humidity progs in the plan view show an extremely narrow moisture starved boundary as it pushes across the area, limited to only a few tens of miles across. The current forecast has likely pops of 50-60% percent between 18-00z which is adequate. The overall ageostrophic circulation is expected to be very weak with lean 850- 700mb frontogenesis. Forecast soundings show static stability lingering between 4.0 -7.0 kft agl limiting coverage of activity with MUCAPES of a few hundred J/kg. Latest Swody2 has now introduced General Thunderstorm designation for Southeast Michigan. Warm temperatures are anticipated Thursday ahead of the front with readings pushing into the lower 70s.

Anticyclonic curvature to the zonal jet streak in portions of central Canada will lead to strongly anticyclonic flow curvature over the Great Lakes Friday and Saturday. High confidence exists in strong static stability between 3.0 and 17.0 kft agl. Southeast Michigan will reside in the gradient to the 1000-500mb thickness tempering high temperatures both Friday and Saturday in the lower 60s.

Longwave ridge is forecasted to build across the region this weekend and then continue into the beginning of next week. Current high temperature forecasts suggest temperatures reaching the middle 60s some 7 to 10 degrees above normal. Any pattern change with the arrival of Pacific energy appears to hold off until after Day 7, Tuesday.

MARINE

Southwest winds will be on the increase tonight ahead of a cold front. However, the warm advection pattern will help limit mixing depths. Nonetheless, the strength of the low level jet and magnitude of the pressure gradient do look to support gusts at or above 25 knots, most prevalent over Central Lake Huron extending back into Saginaw Bay. A Small Craft Advisory has been issued from late tonight through Thursday morning for these wind gusts. Offshore flow, however, should keep waves mostly in the 2 to 4 foot range however.

Behind the cold front, wind speeds look to be maximized over northern Lake Huron where cold advection is most robust. 850 MB temps progged to fall below zero Thursday night, promoting deeper mixing and northwest gusts of 25 to 30 knots. Confidence is high in a period of 25 to 30 knot gusts over northern Lake Huron. High pressure quickly builds into the central Great Lakes Friday afternoon, setting up lighter winds and dry conditions over the weekend.

PREV DISCUSSION

Issued at 153 PM EDT Wed Oct 28 2026

AVIATION...

Controlling area of high pressure exits further into the Atlantic today as a wave of low pressure lifts across the arrowhead of Minnesota. This leads to an uptick in south-southwesterly winds tonight into Thursday as the pressure field responds to the upstream system. Shortwave ridging aloft still lingers nearby overnight, delaying an advancing cloud layer associated with the low's attendant cold front. Ceilings should gradually fill in early Thursday morning from west to east, but likely remain VFR for most of the day. Models continue to advertise marginally sufficient saturation depths to allow a few rain showers to develop along the frontal slope. However, forcing is rather benign through the shallow mixed-layer, prior to 18Z, and rainfall is unlikely to have much impact on visibilities. Added a VFR -SHRA mention for FNT and MBS for the last hour of the TAF cycle, while timing for the remaining TAF sites occurs after the synoptic hour. Not enough confidence for a DTW mention, prior to 00Z, as the front decays across an increasingly dry environment. Post-frontal winds veer westerly.

D21/DTW Convection...No thunderstorms forecast through the TAF period.

DTW THRESHOLD PROBABILITIES...

* Medium for ceiling at or below 5000 feet Thursday afternoon and evening.

DTX WATCHES/WARNINGS/ADVISORIES

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