Marine Weather and Tide Forecast for River Rouge, MI

DISCUSSION

Evening/Early Tonight Severe Storm Potential- Enhanced risk south of I-69, Slight Risk north of I-69:

Remnant MCV over northern Indiana that generated a few light showers near the state border is pushing east of the region this afternoon and most importantly, its associated cloud shield is likewise peeling away. Increasing insolation supports destabilization through the late afternoon-early evening period with CAMs advertising a southwesterly gradient from Grand Rapids to Detroit where 1000-2000 J/kg of SBCAPE to develops along/south. Additionally stalled frontal boundary is lingering near the northern portions of the Saginaw Valley this evening. These two features are the first to watch before the arrival of then ongoing upstream convection from WI/IA late evening. For the southern CAPE gradient, the fairly weak cap looks to effectively erode between 00-02Z supporting isolated to perhaps scattered convective initiation over areas south of M-59.
For the stalled Tri-Cities frontal boundary, its associated initiation depends on enough instability lifting that north which favors a window more 01-03Z. Discrete storms that do manage to fire in either region occur early enough to be fully surface based and be working with at least 1000 J/kg of SBCAPE (likely more for the southern storms) and very steep mid-level lapse rates between 7.5- 8C/km. Additionally wind profiles/hodographs show healthy curvature in the lowest 1-2kft leading to between 100-200 m2/s2 of SRH and 0- 1km bulk shear values nearing 25kts. All together, near-sunset environment is favorable for surface-based storms with all hazards in play, though exactly how much initiation actually occurs is unclear. While the above is (potentially) occuring, upstream convection undergoes upscale growth while crossing from WI into west MI feed by a 45-55kt southwesterly LLJ congealing into a line of storms (wind feed isn't particularly strong true MCS development).
Line motion is favored to trend southerly given the CAPE gradient and southwesterly inflow. Worth noting there is a subset of CAMs like the 06Z HRDPS and 12Z ARW that favor more robust development along the southerly flank resulting in the main line push dropping southeast over northern IL/IN instead of SE MI. That said, current forecast remains with the main line dropping NW-SE across the local area late evening-early tonight, 03-07Z. Overnight arrival lends concern for the ability for the line to maintain itself both in strength and a surface layer root due to decreasing available nocturnal instability and only modest inflow winds. Should anything maintain a surface connection, damaging wind gusts and an isolated QLCS tornado would be the main hazards as low level winds maintain favorable curvature in advance of the line.

Wednesday- Marginal Risk of Severe:

Exactly how Wednesday morning plays out depends on the behavior of this evening's convection and where the line eventually peters out- either over far southern SE MI or over OH. The line pushing fully into OH keeps the first half of the morning drier. Regardless, the local area remains entrenched in this mild/moist airmass with continuing deep layer southwesterly flow. No strong forcing mechanism to speak of Wednesday with embedded PV anomalies instead lifting into the state and spurring clusters of showers and thunderstorms. Airmass is conducive for instability to rebound back near 1000 J/kg by afternoon with bulk shear remaining near 30-40kts offering a shot an isolated storm borderline severe storm. Damaging wind gusts are main hazard, hail threat is hampered by anemic mid- level lapse rates near or below 6C/km.

Thursday- Marginal Risk south of M-59:

Central Plains mid-level trough eventually lifts into the central Great Lakes providing stronger synoptic support for increasing shower coverage late Wednesday night-Thursday morning. Wave provides stronger wind profiles pushing shear values towards 40-45kts.
Inhibiting factor for storms is overnight arrival of the wave with showers ongoing through the day reducing diurnal destabilization potential. Peak CAPE generally favored to hold in the 500-1000 J/kg range and focused towards the state border where 'best' chances for an isolated strong storm will reside. Shortwave eventually kicks east Thursday night tapering off lingering showers.

Flooding Concerns- Flood Watch for all SE MI till Thursday night:

Spring thus far has already been quite wet for much of the area with all 3 climate sites sitting above normal since March 1st: Saginaw +4.30", Flint +3.78", Detroit +0.88". In the past 10 days, all but the southern portions of Lenawee/Monroe have seen between 1.5-4.5", highest values north of M-59 where areal/river flooding occurred last week. Humid airmass maintains PWAT values around 1.3" tonight through the day Wednesday before nudging higher towards 1.5-1.6" Wednesday night-Thursday. With multiple additional rounds of showers and storms this evening through Thursday evening, QPF forecasts within that timeframe are between 1-3" though higher amounts around 4" are possible depending on thunderstorm coverage and tracks. Given the antecedent conditions with this forecast, a Flood Watch has been issued for all of SE MI through Thursday evening.

Late Week:

Mid-level ridging works across the central Great Lakes daytime Friday finally provides a reprieve from rainy weather. This however is shortlived as a broad mid-upper trough digs out of the northern Rockies into the upper Midwest/northern Great Lakes. Attendant surface low sends a respectable cold front through the local area Saturday-Saturday night. Additional showers and thunderstorms are likely in advance with afternoon arrival currently favored. Region is outlooked in a Day 5 15% risk due to the strong wind profile and modest diurnal destabilization potential. Much cooler air follows as 850mb temps fall from +14C Saturday to -8C by Sunday morning and eventually -10 Sunday night as the core of thermal troughing crosses. This results in overnight lows Sunday night below freezing in the upper 20s to around 30F. Given the warm stretch this week, growing season is likely to have started for most of the area which would warrant frost/freeze headlines.

MARINE

Surface warm front has lifted back toward Saginaw Bay, with southwest flow to the south of the front and east flow for points north. Patchy fog persists over portions of Lake Huron north of the front, but overall dry weather is in place. The next round of thunderstorms is expected to develop over northern IL/WI late this afternoon and track east-southeast into the local waterways overnight as a line. Strong to severe storms are expected mainly after 04z (midnight local time), with potential for damaging wind gusts over 50 knots, large hail over 1 inch, and isolated waterspouts. This line of storms exits east around sunrise Wednesday, but unsettled conditions are expected to continue into the weekend. Each round of thunderstorm activity brings potential for localized erratic waves and gusty winds. Widespread headlines are not expected.

HYDROLOGY

Multiple rounds of showers and thunderstorms start this evening and continue off-on through Thursday evening. Each episode brings the possibility for locally heavy rainfall, particularly where focused areas of thunderstorms develop, which offers flooding concerns given the already wet spring and saturated soils. Forecast rainfall totals from tonight to Thursday night range 1-3" across SE MI with potential for 4" dependent on coverage/track of thunderstorms each episode. A Flood Watch is in effect for the entirety of the region into late Thursday night as a result. Widespread flooding chances are tied if areas see repeated thunderstorms and carry low confidence in occurrence, however flooding of low-lying, poor drainage, and urban areas are likely as is creek and river flooding.

PREV DISCUSSION
Issued at 1255 PM EDT Tue Apr 14 2026

AVIATION...

Broad region of subsidence entrenched within a thicker high based cloud will maintain VFR conditions with limited convective potential through early this evening. Late day winds holding from the west to southwest, with some intervals of gustiness into the 25 knot range.
Thunderstorm initiation and expansion expected upstream again early tonight. This activity will shift into lower Michigan overnight, most likely within the 03z to 08z window for an arrival locally.
Overall scale and magnitude still carries some uncertainty, but enough confidence in tsra occurrence to highlight at all locations.
Forecast will allow for dry conditions to emerge within the immediate wake for the latter half of the morning, but some renewed expansion in showers and thunderstorms will be possible depending on convective evolves tonight.

DTW/D21 Convection...Dry conditions favored into the evening hours.
Highest likelihood for thunderstorms will exist between 04z and 09z tonight.

DTW THRESHOLD PROBABILITIES...

* Low for ceilings aob 5000 ft through this evening. High tonight.
Low again Wednesday morning.

* Medium for thunderstorms tonight between 04z and 09z.



DTX WATCHES/WARNINGS/ADVISORIES
MI...Flood Watch from 8 PM EDT this evening through late Thursday night for MIZ047>049-053>055-060>063-068>070-075-076-082-083.

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