textproduct: Detroit/Pontiac

KEY MESSAGES

- Scattered to numerous showers with embedded thunderstorms this morning with lingering showers and thunderstorms possible this afternoon across the south.

- Increasing temperature trends this weekend into early next week. High confidence for temperatures in the mid-upper 80s Monday and Tuesday.

- Multiple opportunities for thunderstorms into early next week. Greatest thunderstorm risk will be Monday afternoon/evening with a Marginal to Slight Risk for severe weather in place for all of southeast Michigan.

DTW THRESHOLD PROBABILITIES

* Low for thunderstorms early Saturday afternoon.

* Low for ceilings aob 5000ft Saturday.

PREV DISCUSSION

Issued at 358 AM EDT Sat May 16 2026

DISCUSSION...

The convective complex that developed across Iowa last evening will continue its march eastward into Michigan this morning. This system will be riding the low level jet with a healthy moisture transport and a mid level wave. Relatively high PoPs (50% or greater) remains in the forecast this morning with convection expected to move through locally during the 10Z to 15Z time frame. Though, nearly all of the hi-res models showing significant weakening of these showers and thunderstorms as they move off of Lake Michigan and arrive with very limited surface instability, if any, in place. This will keep the severe weather potential very low through the morning. A chance for general thunderstorms will remain given the steep mid level lapse rates and elevated instability noted with the 500+ j/kg of MUCAPE. The weakening trend also leads to a weak rainfall signal with QPF on the order of around a tenth of an inch or less across southeast Michigan through the morning hours.

A low end chance for precipitation will exist into the early afternoon tomorrow, but soundings point towards a weak cap at or slightly above 5kft. This should help limit any convective response that would try to take advantage of the better daytime instability that will be present as dewpoints rise into the 60s. Any activity would more than likely be towards the southern border with higher coverage holding south of the state. Greater warm air advection will arrive as well and help daytime temperatures reach upper 70s to low 80s.

A mid-upper ridge will amplify over the Great Sunday into Monday as a result of a PacNW trough organizing over the Rockies. A warm frontal feature is set to lift northward on Sunday as an embedded shortwave lifts out of the plains through the ridging. This will at least offer a chance for showers and thunderstorms during the day with added ascent along the warm front and supporting mid level wave. Hi-res model signal does not seem that excited about the prospects of thunderstorms on Sunday along the warm front across southeast Michigan. Will be something to monitor given the favorable diurnal timing with increasing instability noted with the warm and moist advection, increasing shear profiles and steepening lapse rates. Southeast Michigan remains in general thunder for the Day 2 Convective Outlook as of now, but seems plausible that isolated strong thunderstorms could be in play during the day Sunday. Will continue to monitor the hi-res trends.

Passing of the warm front Sunday will continue the warming trend through Tuesday as deep south to southwest flow sets up and ushers in 850mb temperatures on the order of 15-17C and 925mb temperatures to around 20C for Monday and Tuesday. The result will be summer-like temperatures each afternoon in the mid to upper 80s with 90s possible depending on the cloud and precipitation trends. Greatest chance for 90s will be across the Detroit metro areas. Mid 60s dewpoints will also accompany the heat while supporting additional chances for thunderstorms Monday afternoon into Tuesday. Monday afternoon/evening activity will be supported by the strong thetae surge. The moisture will have gulf ties and PWATs will climb towards 1.75 inches bringing potential for heavy rainfall. The environment will be increasingly supportive of strong to severe thunderstorms across parts of southeast Michigan with favorable shear and instability. A Day 3 Marginal to Slight Risk is now in place across all of southeast Michigan. Thunderstorm threat continues on Tuesday ahead of a cold front. Still a few days to refine details on the severe weather potential early week. Cold front eventually sweep through, bringing temperatures back toward more normal values by Wednesday. High pressure will also build into the region resulting in a period of dry weather mid to late week.

MARINE...

A line of thunderstorms tracks across Lower Michigan over the next several hours, reaching the local marine zones around daybreak. Most storms remain elevated, although a few storms will be capable of gusty winds in excess of 30 knots. The leading line clears out by mid-morning, with a weaker signal for additional storms to fire early this afternoon along the lingering surface trough. Drier conditions emerge late afternoon-evening while high pressure sends a cold front south across the Great Lakes tonight. This front clashes with the warmer airmass/ridge over SE CONUS, with the southern stream eventually winning out for Sunday through early next week. Split flow Sunday flips fully to the southwest Monday and Tuesday ushering in a seasonably warm and unstable airmass. The main marine concern will be potential for several rounds of showers and thunderstorms, although breezy southerly winds are expected to develop along the nearshores (gusting 20 to 30 knots).

DTX WATCHES/WARNINGS/ADVISORIES

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