textproduct: Detroit/Pontiac

KEY MESSAGES

- Dry weather expected tonight and Tuesday.

- Slightly cooler than normal temperatures continue through mid to late week.

- The next chance of rain arrives Wednesday evening and lingers into Thursday.

- Warming temperatures this weekend with additional rain chances.

DISCUSSION

Low pressure peels away from the Ohio Valley toward the east coast this evening, drawing the deeper column moisture along with it. This has led to a gradual decrease in cloud cover from north to south, although northeast flow off of Lake Huron maintains a healthy cover of diurnal cumulus through the early evening. Waning cyclonic influence and inbound surface high pressure cause winds to back northerly tonight, which helps shut off the lake influence in favor of mostly clear skies overnight.

Pair of PV anomalies over Canada and ridging over SW CONUS govern the height field through most of the week, maintaining a broad longwave troughing pattern and seasonably cool conditions with daytime highs in the mid-upper 70s. Highest confidence in dry weather is Tuesday as PWAT values drop to 0.6" with a deep layer of static stability in the lowest 15.0 kft. Main item of uncertainty for Tuesday is cloud cover, which may come in the form of high cloud advecting in from the Dakotas and/or a scattered boundary layer cu field. Mixture of sun and filtered sunshine thus expected for Tuesday.

Trailing PV anomaly currently over Saskatchewan reaches the international border Wednesday morning, leading to top-down theta-e advection into Lower Michigan during the day. Cloud cover thus expected to increase, especially in the afternoon and evening. Remnant anticyclonic influence keeps much of the Detroit area dry through the daylight hours Wednesday, with the best shot at earlier rain chances for the Saginaw Valley/Thumb on the nose of the upper level jet streak. Forecast soundings depict disjointed column moisture through most of Wednesday night, as moisture transport will likely be disrupted to some degree by widespread convection over southern CONUS. Highest PoPs are thus anchored to the passage of the cold front itself between 00z and 12z Thursday. Thunderstorms are in play with this activity, although soundings are not particularly impressive from a convective standpoint as lapse rates only briefly peak around 6.5 C/km which caps MUCAPE ~500 J/kg. In general most areas see up to a couple tenths of an inch of QPF, although some higher outliers exist mainly in solutions that bring the occluding low directly overhead. Lingering showers/a few thunderstorms possible into Thursday afternoon as the boundary layer destabilizes and the low stalls over Lake Huron.

Drier conditions return for Friday as surface high pressure and mid- level ridging briefly build into the Great Lakes. Still several upstream shortwaves on deck, forming the next opportunities for showers and thunderstorms this weekend. Meanwhile, an anomalous low arrives onshore the Pacific Northwest this weekend with decent agreement in its timing between ensemble members and cluster analysis. There are some differences in how deep it carves across western CONUS, which will then impact downstream ridge amplification over the eastern half of the country. While this generally signals a warm up early next week, the magnitude of the warm up is uncertain.

MARINE

As the Upper Ohio Valley system continues to move east, the wind really isn't up enough to keep the SCA for Lake Erie and will cancel that early. The northeast wind will increase more than it is going at 18z, specifically around 03z to 07z overnight, but not enough to keep the SCA. Wind direction will continue to back north to northwest in the wake of the low through the early week period as high pressure builds in. Lighter winds are expected tomorrow and Wednesday. Winds will then increase to around 10 knots from the south and southwest late Wednesday and into Thursday ahead of the next low pressure and frontal system.

PREV DISCUSSION

Issued at 1250 PM EDT Mon Jun 22 2026

AVIATION...

Remnant MVFR clouds continue across the Detroit airspace. Farther north, drying near the surface has resulted in a reduced coverage VFR cumulus field. Continued drying across the airspace will occur as the boundary layer continues to grow and more aggressive mixing takes shape. Northerly winds will increase as a result - and contain a modest gust component - while the clouds continue to thin and fade. Very quiet conditions will establish tonight into Tuesday.

D21/DTW Convection...No thunderstorms expected tonight and Tuesday.

DTW THRESHOLD PROBABILITIES...

* High for ceiling at or below 5000 ft early this afternoon.

DTX WATCHES/WARNINGS/ADVISORIES

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