textproduct: Detroit/Pontiac

KEY MESSAGES

- Sunshine today with temperatures climbing into the upper 50s to lower 60s.

- Rain chances increase late Wednesday into Thursday, with an unsettled pattern continuing into the first half of the weekend.

- A much colder airmass arrives Thursday, triggering lake effect rain and snow showers late Thursday through Saturday.

DTW THRESHOLD PROBABILITIES

* None.

PREV DISCUSSION

Issued at 408 AM EST Tue Nov 10 2026

DISCUSSION...

Mild and dry conditions define the start of the forecast period today with temperature readings currently in the mid 40s across SE Michigan. Light southwest flow this morning will veer to the west- northwest by mid day as a surface trough glances across the region. Not much of an impact to sensible weather aside from the wind shift, although very strong isentropic downglide will reinforce static stability aloft and dry weather. Boundary layer growth gradually erodes the inversion to bring high temperatures into the low 60s.

A more active pattern emerges for the second half of the week, beginning with a Pacific wave which was just sampled over the Pacific Northwest. The pattern amplifies substantially Wednesday as a ~100 knot jet streak digs south and sends the PV anomaly into the southern OH/TN Valleys by 00z Thursday. This drags the main height fall center south of the state line, but does position SE Michigan within a prolonged period of moist isentropic ascent Wednesday afternoon-early Thursday morning. With cold air and a second wave crashing in from the north, there is potential for FGEN banding to develop within the broader rain shield. If this occurs, a narrow swath could see over a quarter inch of rain before lake effect kicks in. The added cloud cover and beginnings of cold advection hold highs Wednesday in the low-mid 50s.

The low deepens and matures as it moves into the mid-Atlantic Thursday morning, in part due to the trailing wave phasing into it. The first implication of this is an increase in the northerly gradient wind, which will become breezy (gusts of 25-30 mph). Second is the development of an inverted trough axis that will be one of the focused opportunities for lake enhanced showers. Thursday is where precipitation type uncertainty first comes into play. Forcing along the surface trough may become very concentrated, producing strong upward vertical motion that corresponds to intense precipitation rates and diabatic cooling potential. On the other hand, there are still differences in the timing and magnitude of the trough along with the role of a warmer marine layer. For now, will advertise potential for melting snowflakes to mix in as early as Thursday.

Once this trough sweeps through, a more aggressive surge of cold advection follows with h8 temperatures quickly dropping into the negative single digits and fully activating the lake effect response for Friday. Wet bulb zero heights gradually lower through the day below 2.0 kft agl as post-low winds back to the northwest and advect drier dewpoints into SE Michigan, increasing potential melting snowflakes to reach the ground. Forecast soundings show impressive moisture depths above 10.0 kft agl for Friday with steepening low level lapse rates to support a convective/lake enhanced shower environment. Certainly some diabatic cooling potential here as well, which allows for the snowflake potential despite highs reaching the low 40s. A more localized detail is the Lake Huron convergence band that appears in the bulk of model guidance. Marine layer influence will again struggle to get cold enough for snow, although diabatic cooling can be sneaky in these early season events. Moisture depths gradually decrease through the day Saturday while winds shift more to the northwest, which generally shuts down precipitation chances. The cooler airmass however sticks around through the weekend, with highs Thursday through the weekend in the 40s.

MARINE...

Low pressure swings from Ontario into Quebec during the morning hours as its attendant dry cold front crosses the central Great Lakes. This leads to a west-northwesterly wind shift with an uptick in speeds. Improvements to mixing depths due to cold air advection and mild water temperatures could lead to an occasional post-frontal gale-force gust over portions of the northern Huron basin, but coverage and frequency appear too limited to warrant any gale- related headlines. A Small Craft Advisory remains in effect for The Thumb nearshores given a brief wave response, maximizing around 6 feet. The progressive pattern continues tonight into Wednesday as high pressure tries to build in, but gets displaced by surface low pressure digging into the Ohio Valley Wednesday night. Gusts to gales are possible Thursday and/or Friday with strong on-shore northeasterly gradient flow stemming from the vicinity low. Some potential exists for a waterspout or two during this time-frame as shower activity arises.

DTX WATCHES/WARNINGS/ADVISORIES

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