textproduct: Detroit/Pontiac

KEY MESSAGES

- Warmer today with mostly dry conditions through the bulk of the day.

- Showers and thunderstorms expected mainly after 8pm this evening into tomorrow morning.

- Stretch of below average temperatures latter half of the week.

DTW THRESHOLD PROBABILITIES

* Moderate for thunderstorms tonight.

* Moderate for ceilings aob 5000 feet after midnight, high Tuesday morning.

PREV DISCUSSION

Issued at 332 AM EDT Mon Apr 27 2026

DISCUSSION...

Mid-upper level ridge axis slides east this morning with mostly dry and stable conditions expected to hold through today. Lower level flow will gradually settle out of the east this morning and eventually southeast by this afternoon in response to the upstream low pressure system and the high pressure to the east. This will bring a more notable increase in warm air advection today as 850mb flow turns southerly and draw in 850mb temperatures of 11-12C with 925mb temperatures peaking at around 15C this afternoon. Mixing profiles support daytime high temperatures in the low-mid 70s for inland areas while slightly cooler temperatures will exists along the lakeshores give the onshore flow. The approaching warm front arrival with the increasing mid level moisture noted by the increasing mid-high clouds may allow for isolated showers/sprinkles this afternoon. No need to increasing PoPs due to the dry and stable surface conditions as 15-20% should suffice in western portions of the CWA. Increasing pressure gradient and mixing heights will bring wind gust potential up to 30-35 mph later this afternoon with the higher end of the spectrum mainly across the Saginaw Valley and Thumb.

The low pressure system across the mid Mississippi Valley will eject northeastward throughout today reaching Lake Superior area by early tomorrow morning. Ongoing convection associated with this system will be driven through the Midwest during the evening. Still some differences in the hi-res space in regards to exact arrival of convection depending on how activity evolves through the evening. Activity should arrive to southeast Michigan in the 23-03Z window with likely rain and a chance for thunderstorms along the warm frontal zone into the overnight. Strong instability will be lacking with the bulk of activity moving through at the diurnal minimum, but there may be enough instability to support elevated thunderstorms. Of note, several solutions point towards a generally weakening and waning coverage by the time it arrive locally given the lack of instability. PWATs arriving within the main corridor of higher thetae are up to near 1.25 inches, which supports average rainfall amounts in the 0.20-0.50" range. Latest guidance has lowered QPF amounts across the eastern half of the CWA resulting from that model signal for waning coverage and intensity. Any thunderstorm that can manage to maintain some strength could still produce rainfall amounts greater than a half inch given the available moisture. The systems cold front will push through mid-late morning tomorrow, which will maintain chances for precipitation through the morning.

Cooler and drier air will settle into the region in the wake of the morning cold front tomorrow with afternoon highs dipping slightly into the upper 50s across the north to low-mid 60s across the south. A southern stream wave triggers a low pressure system along the frontal zone that lifts across the Ohio Valley tomorrow night into Wednesday. While drier air will have entered the region, enough favorable forcing with the system may produce scattered light showers across parts of the area, mainly south and east portions of the CWA. Bulk of activity with that system is currently forecast to hold south of the state.

Broad troughing extends out from Central Canada during the remainder of the week that will carry periodic embedded waves over Michigan. The result will be at least occasional low chances for precipitation in the form of isolated to scattered light rain showers during this period. Otherwise, expect most of the area to stay dry for the late week. Troughing and persistent north to northwest flow during this time likely brings slightly below normal temperatures with highs in the 50s and overnight lows in the 30s.

MARINE...

High pressure remains overhead to start the day before gradually departing to the east late this afternoon-evening. As this occurs, southeasterly winds begin to strength as the next low lifts out of the central Plains towards the northern Great Lakes. A 45-60kt LLJ develops over the central Great Lakes tonight however accompanying warm advection promotes a stable overlake thermal profile limiting mixing potential. Local probabilistic guidance only advertises around a 30% chance to reach 34kts. Given the thermal profile, confidence is not high enough that Lake Huron will see 3 consecutive hours of gales to warrant a warning. That said, can't rule out some gusts near 34kts, particularly over the north-central waters where fetch is maximized. Slightly better potential for strong gusts comes with the arrival of showers and storms late night-early Tuesday as rain promotes a shift towards more neutral profiles, however this set-up would warrant short-fused special marine warnings over gales. Small Craft Advisories are in effect for all nearshore waters this evening into Tuesday due to winds/waves. System's cold front crosses daytime Tuesday ending storm chances as well as flipping winds to the northwest. Rapidly weakening pressure gradient on the backedge of the low keeps these winds under 30kts as weak high pressure briefly follows.

DTX WATCHES/WARNINGS/ADVISORIES

MI...None. Lake Huron...Small Craft Advisory from 2 PM this afternoon to 10 PM EDT Tuesday for LHZ421-422.

Small Craft Advisory from 2 PM this afternoon to 4 PM EDT Tuesday for LHZ441>443.

Lake St Clair...Small Craft Advisory from 8 PM this evening to 4 PM EDT Tuesday for LCZ460.

Michigan waters of Lake Erie...Small Craft Advisory from 8 PM this evening to 4 PM EDT Tuesday for LEZ444.