textproduct: Detroit/Pontiac

KEY MESSAGES

- Showers and thunderstorms develop this evening and taper off late tonight. There is a Slight Risk of severe storms along and south of the I-94 corridor. All hazards possible (wind, hail, and tornadoes), but hail will be favored.

- Sharply colder air arrives tonight and Friday, followed by a steady warming trend through early next week.

AVIATION

Widespread MVFR restrictions in a combination of lower cigs and visiblity this evening as showers persist along an elevated frontal zone. Observational and radar trends suggest rapidly declining thunderstorm potential across the Detroit airspace as stability takes a greater hold with time after 00z. Prevailing wind from the north will remain modest gusty at times tonight. Lower stratus will linger as showers decline in coverage and colder air surges southward. Potential for clearing of lower cloud will increase from north to south during the morning period Friday. Period of drier conditions will support VFR with mostly clear skies Friday afternoon.

For DTW...Radar trends indicate the potential for thunderstorms will remain south of the airport after 00z this evening.

DTW THRESHOLD PROBABILITIES...

* High for cigs below 5000 ft tonight. Low Friday morning.

PREV DISCUSSION

Issued at 347 PM EDT Thu Mar 26 2026

DISCUSSION...

For this evening... Widespread showers and embedded thunderstorms to expand along and in the wake of an advancing cold front as stronger large- scale ascent increases in conjunction with an approaching 700mb jet. The greater severe weather threat remains conditional and partially tied to a narrow and limited time window within the warm sector, focused mainly south of I-94.

Forecast soundings highlight impressive bulk shear values ranging between 70-80 knots through the afternoon and evening, which is readily apparent within storm relative hodographs, noting the elongated extension from 1km through 6km, with a significant streamwise component. That said, the conditionality of strong to severe storms will be tied to the rapid cold frontal progression and associated cold air intrusion which will undercut any late afternoon activity and favor a transition from surface-based storms to elevated convection. This creates a setup where any storm able to briefly remain rooted within the warm sector just ahead of the front could organize quickly and produce a window for severe weather. All storm modes would be possible in this scenario, which includes an isolated tornado, damaging wind gusts (60+ mph) and/or large hail (2+ inches). However, the current response relative to the latest 12Z cams has been relatively muted under copious cloud cover and under some scattered early afternoon rain showers.

Thus the more favorable evolution for today trends toward elevated convection after the surface cold front moves through, which is now just north of I-94. The primary hazard with this setup would be large hail with any severe thunderstorm development. The aforementioned strong kinematics in the 1-6km layer and mid-level lapse rates 7-8C/km with modest MUCAPE does bring the potential to see 2+ inch hailstones in a higher-end scenario through the evening, again favored around I-94 and south. Some low end chances for hail to an inch will be possible north through M59 where mid-level lapse rates are weaker. Rain and thunderstorm chances end from north to south between 8PM to around Midnight. Strong cold air advection in the wake of the cold front drops overnight lows into the 20s.

Continued caa tomorrow with 850mb temperatures ranging from -5 to - 10C by 18Z will hold temperatures in the low 40s through the Metro region down to the MI/OH border and into the low 30s to upper 20s within the Thumb under the cooler northeast flow. Passage of a shortwave late Friday through Saturday morning brings low chances (20%) for snow showers. High pressure fills in across the Ohio Valley on Saturday supporting dry weather with return flow from the departing high then bringing in warmer air through the early week period.

MARINE...

A cold front moves through the central Great Lakes today with showers and thunderstorms developing ahead of the boundary. Locally higher winds/waves are possible in some storms, and a few could intensify to meet thresholds for Marine Weather Statements and/or Special Marine Warnings. Should storms intensify, strong wind gusts of 34+ knots are possible, particularly during the evening hours for the southern waterways (Lake St. Clair and western Erie). Post- frontal cooling will be stark, but a decrease in low-level northerly flow should limit nocturnal mixed-layer gustiness to 30 knots or less. Modest on-shore post-frontal gradient winds still support Small Craft Advisory level waves through Friday. Winds and waves expected to remain in-check over the weekend with mainly dry conditions into Monday.

HYDROLOGY...

Showers and scattered thunderstorms are expected through the evening hours as a cold front sweeps through Lower Michigan. Consensus model guidance QPF totals generally between 0.25 and 0.75 inches through Thursday evening, with the higher totals near the southern Michigan border. Highly localized totals nearing an inch or more cannot be ruled out with any stronger thunderstorms. Highly localized flooding in urban small streams and/or ponding of water in poor drainage areas will be possible with any thunderstorms.

DTX WATCHES/WARNINGS/ADVISORIES

MI...None. Lake Huron...Small Craft Advisory until 4 PM EDT Friday for LHZ421-441>443.

Small Craft Advisory until 10 AM EDT Friday for LHZ422.

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