textproduct: Detroit/Pontiac

KEY MESSAGES

- 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 Sunday evening.

* Low for ceilings aob 5000ft through Sunday.

PREV DISCUSSION

Issued at 408 PM EDT Sat May 16 2026

DISCUSSION...

Quiet weather expected the rest of today and through most, if not all, of the overnight as we fall in between mid level waves with a brief period of zonal flow aloft. There is a very limited amount of support for some isolated nocturnal showers to develop along a former cold front stalling across southern lower MI. Instability is weak and elevated, lapse rates are poor, and moisture quality is poor with PWATs around 0.75 inch. Warming low levels will also create a cap which will add to challenges. This time of year though, with this pattern, all it would take is some weak small scale impulse to spark something.

Warm advection ramps up Sunday as the stalled front gets pushed back north as a warm front tied to a developing low pressure system over the Plains. Strong low level jet surging north along the Mississippi River tonight will force the front northward Sunday afternoon with the eastern tail of it lifting through SE MI. There is a narrow axis of vorticity aloft pivoting through the area as well but only a weak axis of 700mb theta e over the region. Warm advection will lead to pretty deep cap from 850 to 750 mb with surface temps rising into the low 80s. SPC Day 2 has expanded the region of Marginal Risk across the northern half of the CWA to account for the warm front, modest shear aloft around 30 knots, and skinny elevated instability around 500-1000 J/kg. Elevated hailers would be the primary threat with wind a far second owning to the deep layer of capping the wind would have to punch through. Timing would be between 1 and 9 pm. Models are hinting at a shortwave or convective cluster riding east along the front through Mid MI after about 22Z so something else to watch for.

Sunday night into Monday looks to be quiet as we are solidly in the warm sector with 850mb temps rising into the mid to upper teens C. Mondays high temps will be in the mid to upper 80s and depending on cloud cover, some guidance has been leaning toward 90. This may be hard to achieve though as models are also showing upstream convection on the prefrontal trough pushing east through the day which may bring some showers or thunderstorms to the area during the afternoon. The cloud debris at a minimum should temper max t potential. SPC Day 2 has SE MI in Moderate to Slight Risk of severe storms for late Monday and Monday night. Continued warm air advection with a surge of theta e after 21Z will increase CAPE values to around 1500 J/kg with strong lapse rates in the mid levels and in the BL with only a small cap around 800mb to contend with. Convective chances will continue on Tuesday, as well as the heat, as the cold front won't pass through til Tuesday night. SPC Day 4 continues the Slight Risk over the region. The passage of the cold front and high pressure building into the region out of the northern Plains with very broad troughing over the Great Lakes will lead to cooler conditions for the middle to end of the week with highs back down hovering around 70.

MARINE...

Breezy southwest flow is ongoing with drying conditions as a surface trough exits into Ontario. Gusts briefly peak around 25 knots along the Lake Huron shoreline this afternoon, but subside this evening with the loss of daytime heating. A cold front then settles south across the Great Lakes tonight, stalling over southern Lake Huron Sunday and flipping winds to the northwest for the majority of the open waters. The stalled front will be the focus for additional thunderstorm chances beginning Sunday afternoon, some of which may produce wind gusts in excess of 35 knots and hail to one inch. The front then lifts back north as a warm front Sunday night, pushing thunderstorms into northern Lake Huron by Monday morning. Unsettled conditions continue Monday-Tuesday as a warm and unstable airmass takes hold, with thunderstorm chances existing both days. Breezy southerly flow is also expected early in the week, especially near the shoreline where gusts may exceed 30 knots at times. Small Craft Advisories will likely be needed. A cold front then tracks through the area mid-week, followed by high pressure.

DTX WATCHES/WARNINGS/ADVISORIES

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