textproduct: Detroit/Pontiac

KEY MESSAGES

- Dry and warm today and Tuesday.

- Showers with a chance of thunderstorms Tuesday night and Wednesday.

DTW THRESHOLD PROBABILITIES

* None.

PREV DISCUSSION

Issued at 311 AM EDT Mon Sep 7 2026

DISCUSSION...

The continued dominance of low to mid level anticyclonic flow across Lower Michigan will provide another dry day across the forecast area. After a relatively cool morning, daytime heating will again boost afternoon highs into the upper 70s/near 80. Aside from a few cu, some cirrus may continue to stream into the area from the west. Otherwise, ample sunshine will prevail within the dry ambient airmass. The mid level anticyclone and associated surface high will be driven across the eastern Great Lakes Tuesday as an expansive region of mid level height falls encompass the northern Plains and upper Midwest. Southerly return flow will advect a slightly warmer and more humid airmass into southern Michigan. Model guidance is strongly supportive of highs into the low 80s Tuesday. The moisture advection may allow some increase in cloud cover during the day while a strong capping inversion inhibits convection.

The aforementioned height falls will be associated with a progressive mid level low moving from the Canadian high plains Tuesday into northern Ontario Wednesday. This system will send a cold front into Lower Mi Wednesday and will flatten the large ridge across the Conus. This will place the Great Lakes region within stronger mid/upper level westerlies.

Of note within the last few runs of the model suite has been a plume of deep layer moisture circulating around the large ridge and advecting into Lower Mi Tues night/Wednesday in advance of the cold front. ECMWF ensemble members indicate precipitable water values ranging anywhere from 1.8 to 2.2 inches within this moist axis, quite high for anytime of the year in the Michigan. The advection of the deep layer moisture plume into Lower Mi Tuesday night will warrant a chance of convection, especially across the northern portions of the forecast area. Conditions will be favorable for upscale convective growth to the west/southwest of Lower Mi Tuesday night. Downstream propagation of any remnant convection/MCV(s) into Lower Mi Wednesday will warrant a chance of showers/thunderstorms. Residual cloud cover and precip leads to some uncertainty as to the advection of instability into Se Mi Wednesday. While the operational NAM is quite bullish on instability, the majority of model solutions and their ensemble members continue to hint at overall weak instability across Se Mi, with the axis of higher daytime instability remaining south of the state. With the low level frontal boundary and moist axis aligning more parallel to the mean flow Wednesday, even weak convection may support some prolonged rain and thus locally high rain totals. More notable short wave energy forecast to traverse the northern lakes late Wed/Wed night is forecast to drive the frontal system into the Ohio Valley, bringing a little cooler and drier airmass to forecast area for the later portion of the work week.

MARINE...

Benign marine conditions continue through most of Tuesday due to surface high pressure moving from the central to eastern Great Lakes. The next chance for increasing winds and waves arrives Tuesday afternoon, ahead of a seasonably strong low pressure system tracking across southern Canada into Hudson Bay. Robust Gulf- modified southwesterly low-level flow and the associated warm then cold fronts should lead to rising shower and thunderstorm chances midweek. Pre-frontal winds/waves should peak Wednesday afternoon with the possibility of borderline gusts to gales for portions of Lake Huron. Drier and cooler conditions are expected for the rest of the workweek as winds turn northwesterly within a modest pressure gradient. Small Craft Advisories will likely be needed on Wednesday for at least the Lake Huron nearshores.

DTX WATCHES/WARNINGS/ADVISORIES

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