textproduct: Detroit/Pontiac

KEY MESSAGES

- Chance of light rain and drizzle through tonight. Additional minor chances for light rain each afternoon both Thursday and Friday.

- A stretch of well below average temperatures will exist thru this weekend. This will bring potential for frost/freeze conditions each morning Friday through Sunday.

DISCUSSION

A notably cooler environment firmly entrenched today, as an initial period of meaningful large scale height falls occur atop prevailing low level northeast flow. Associated broad, weak ascent within the moist cyclonic flow will maintain some pockets of light rain or drizzle into the early evening hours. Potential for an uptick in coverage early tonight, as greater height falls tied to an inbound higher amplitude wave shifts an inverted surface trough toward the area. Overall moisture quality and depth supportive of a chaotic coverage and will continue to highlight potential thru the early morning hours. The likelihood for a higher coverage of cloud cover to linger well into the night, combined with a persistent light gradient, will provide a higher prospective floor for low Thursday morning. Forecast will continue to highlight readings ranging from mid 30s to lower 40s. Some patchy frost plausible in this environment, but widespread coverage appears unlikely.

Upper low forecast to anchor north of lake Superior over the next 24 hours, effectively maintaining a stretch of cooler and potentially unsettled conditions to finish the work week. Brief bouts of pva as weak shortwave energy transit the existing mid level cyclonic periphery may combine with steepening diurnally enhanced lapse rates to offer a lower probability for shower production both Thursday and Friday. Slightly greater signal exists Friday, as highlighted by latest blended model guidance. Coldest conditions this period likely noted Friday, as a secondary window of cold air advection drags 850 mb temperatures below -5c. Highs ranging from mid 40s to lower 50s. Frost/Freeze considerations will exist, particularly Fri night as overnight temperatures more definitely push below freezing early Saturday morning.

Higher magnitude cold for early May standards will exist through Saturday within deep layer northwest flow. Daylight temperatures again struggling to eclipse 50 degrees. Resident polar thermal profile will steadily vacate starting Sunday within the backdrop of modest height rises and brief warm air advection as low level flow emerges from the southwest within the immediate wake of exiting surface ridging. A more seasonable airmass then entrenched heading into early next week. Large scale pattern maintains some level of general troughiness with a favorable trajectory for additional mid level impulses to pivot through, suggesting a potentially wet pattern may emerge at times during the early week period.

MARINE

Upper troughing holds across the Great Lakes through the remainder of the work week maintaining cooler, unsettled weather though little to no thunderstorm chances as a result. Low pressure lifting out of the Ohio Valley into the eastern Great Lakes shifts winds from the northeast to northwest tonight with this flow direction largely holding through Friday. Speeds stay on the modest side owing to a fairly diffuse gradient with gusts holding at or below 20kts. Period of high pressure favored to emerge this weekend before the unsettled pattern returns to start next work week.

PREV DISCUSSION

Issued at 110 PM EDT Wed Apr 29 2026

AVIATION...

Trough influence firmly in place this afternoon supporting lower VFR with pockets of MVFR cloud and scattered showers/drizzle. Ongoing conditions largely persist as is through the rest of the afternoon before the driving wave swings over the area this evening. Based on upstream obs and model guidance, expectation is for wider spread light shower coverage as well as lowering ceilings toward MVFR more being predominant. How long these showers last overnight carries high uncertainty with solutions ranging from fizzling out late evening to lingering into early Thursday morning. For now have opted for a middle ground in the current forecast. Some improvement in ceiling heights back to lower VFR favored Thursday morning.

D21/DTW Convection...No thunderstorms expected through this TAF period.

DTW THRESHOLD PROBABILITIES...

* High for ceilings at or below 5,000 feet through tonight.

DTX WATCHES/WARNINGS/ADVISORIES

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