textproduct: Detroit/Pontiac

KEY MESSAGES

- Line of showers and thunderstorms early this morning will be capable of wind gusts to 40 mph before exiting into Ontario by daybreak.

- Isolated thunderstorm redevelopment possible early this afternoon. There is a marginal risk for damaging winds and large hail.

- Dry Sunday and Monday followed by building heat with reoccurring periods of thunderstorms Tuesday onward.

DTW THRESHOLD PROBABILITIES

* Low in thunderstorms this afternoon.

* Moderate for ceiling 5000 ft or less today.

PREV DISCUSSION

Issued at 400 AM EDT Sat Jun 6 2026

DISCUSSION...

Ongoing line of convection stretches from Lapeer to Coldwater, marching steadily eastward at 45 mph. This line continues to decay as it encounters a more stable environment over SE Michigan. Nonetheless, most locations see measurable rain before the line departs into Ontario by 10z (6am). Drier air then filters in for the morning hours, with pockets of clearing possible especially across the north given trends over northern lower Michigan/Wisconsin.

Weak cold front slowly drops across southern Michigan through the day, noted by a subtle veering trend in wind direction and lowering dewpoints. Not much of an impact on temperature prospects, as most areas are forecast to reach the low to mid 80s this afternoon. The front reaches the I-94 corridor around the time that boundary layer destabilization begins early this afternoon, coincident with a renewed region of large scale ascent as a second embedded wave ripples along the Ohio border. This wave should help isolated cells break through the remnant subsidence bubble from this morning's convection. The strongest updrafts will be able to take advantage of mid-level dry air (DCAPE over 1000 J/kg) and lapse rates ~6.5 C/km, capable of producing isolated damaging winds and large hail. Outside of isolated thunderstorm activity along/south of I-94, most of SE Michigan stays dry after this morning round of convection exits.

Post-frontal anticyclonic flow develops this evening, clearing out moisture with PWAT values dropping to roughly 0.7" by Sunday morning. This establishes a sharp moisture gradient upstream that will stall on the periphery of the high through at least Monday morning. Locally, a dry and stable column affords plenty of sunshine Sunday and early Monday while 500mb heights approach an anomalous 590 dam overhead (99th percentile climatologically). Daytime highs in the low to mid 80s will be the coolest we see through the rest of the forecast period.

Ridge amplification will quickly be disrupted by the slow migration of a Pacific wave toward the Great Lakes, releasing the moisture gradient into SE Michigan Monday afternoon. Modest height falls then peak Tuesday while moisture transport ramps up to bring the next opportunity for widespread showers and thunderstorms to the area. Main concern for Tuesday is a heavy rainfall threat as a very moisture-rich environment develops (low 70s dewpoints and PWAT of 2.0 inches) alongside tall/skinny CAPE profiles and weak cloud layer winds. WPC maintains a Marginal Risk for excessive rainfall across Lower Michigan. The severe threat will be much more isolated and mainly the result of any precipitation-loaded downbursts given weak column winds.

Return flow becomes well established Wednesday onward as 850mb temperatures climb toward 20 C. This leads to a warming trend in which highs are forecast to be in the upper 80s to low 90s and heat indices nearing 100 degrees given the humid antecedent airmass. Destabilization is expected each day leading to daily afternoon- evening thunderstorm chances, which introduces uncertainty to the high temperature forecast. Nonetheless, next week brings several flavors of impactful weather to watch: heat, heavy rain, and thunderstorm potential.

MARINE...

Weak surface low tracking through northern Lake Huron early this morning taking the bulk of the showers with it. Bulk of the day today looks dry, with light, mostly westerly winds today. However, a weak cold front will sink southward late in the day, serving as the focal point for scattered, potentially marginally severe thunderstorms, with the highest probability over Lake St. Clair and Lake Erie. Very light northeast flow and dry conditions will follow for Saturday night and Sunday. Warm and humid weather returns early next week, bringing showers and thunderstorms on Tuesday. An upper level ridge will become reestablished for the mid week period, resulting in mainly light winds and and hot temperatures through the end of the work week.

HYDROLOGY...

A line of decaying showers and thunderstorms impacts SE Michigan early this morning with rainfall totals of 0.25 to 0.75" possible. Isolated thunderstorms may then redevelop early this afternoon (primarily south of I-94), bringing localized daily rainfall amounts over an inch. The extended period of dry conditions recently suggests the potential for flooding is low, but isolated flooding will be possible if any of the higher amounts affect the typical flood prone locations in urban areas. Additional showers and thunderstorms are expected next week as an extended stretch of warm and unstable conditions develop. Heavy rain will be possible Tuesday onward.

DTX WATCHES/WARNINGS/ADVISORIES

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