textproduct: Detroit/Pontiac

KEY MESSAGES

- A narrow corridor of lake effect rain showers (briefly mixed with melting snow) persists today and tonight, mainly along the southern Lake Huron shoreline.

- Mostly cloudy skies expected elsewhere through the weekend.

- Brisk morning winds drop wind chills into the 20s (isolated upper teens), followed by similar conditions Sunday morning.

- Dry weather expected area-wide Monday through Thursday with a steady warming trend.

DTW THRESHOLD PROBABILITIES

* High for ceilings at or below 5,000 feet today and tonight.

PREV DISCUSSION

Issued at 232 AM EST Sat Nov 14 2026

DISCUSSION...

The synoptic environment continues to evolve as expected given the highly amplified omega block draped across CONUS. Southeast Michigan remains positioned near the eastern longwave trough axis which will undergo a restructuring during the course of the day. The primary upper low is expected to become absorbed by a retrograding 528 dam 500 mb low tracking southwestward along the St. Lawrence River, which then settles over the Northeast this evening. Meanwhile, upstream longwave ridging drifts eastward, easing into the Upper Midwest/Minnesota. This results in the local area becoming positioned between the complementary waves while an embedded speed max transits due south over the central Great Lakes. The CVA induces subtle forcing aloft to maintain localized areas of lake effect precipitation for most of the day. However, coverage will be limited to the eastern Thumb and locations along the immediate southern Lake Huron shoreline, after northerly flow backs north-northwesterly later today.

Thermodynamically, deterministic solutions indicate slight degradation of the existing thermal trough as weak warm advection slips in from the encroaching ridge. 850 mb temperatures should lift by 2 or 3 C today, but still anomalously cold, resulting in highs only in the mid 40s. Regarding precipitation type within the narrow corridor of lake effect showers, forecast soundings reveal eventual drying through the DGZ as flow backs between 5 and 7 kft AGL. This limits the likelihood for ice nuclei, therefore, rain is the preferred hydrometeor form as the day progresses. Note that some snowflakes could still mix in during the morning hours today given deeper saturation depths. Not as chilly overnight thanks to insulating lake stratocumulus, but still colder than normal.

The lower tropospheric anticyclone builds northeastward out of the Mid-Mississippi Valley Sunday, weakening boundary layer flow. Lower column winds now look to retain a northwesterly, if not north- northwesterly trajectory well into the afternoon hours, but the lack of shear should suffice in concluding residual lake effect precipitation by mid afternoon. Likewise, lake induced clouds will linger into Sunday evening, and likely into the overnight hours. Significant column drying and subsidence ensue Sunday night as the longwave ridge crosses overhead. 1030 mb surface high pressure gradually builds into the Ohio Valley with time which flips weak gradient flow southwesterly.

Temperatures moderate throughout next week as the ridge flattens but lingers from southern Appalachia into the Southeast. This preserves an increasingly confluent stream of milder Gulf-modified air from the southwest. A progressive Pacific wave unblocks the pattern and is what causes the ridge to de-amplify, but mid-range guidance continues to delay the arrival of embedded shorter wavelength cyclonic features until Thursday or Friday. Still, most of the QPF associated with the passing surface reflection tracking across the UP/Lake Superior also holds farther north. Solutions also differ in the passage of the attendant cold front, with warm advection possibly hanging on as the next wave's deeper core preserves southwesterly flow into the weekend. Global models suggests 850 mb temperatures could make a run at 10C late next week, suggesting 2m temperatures above 60F may be achievable. Some ensembles families support this case, in addition to the lack of measurable precipitation before the weekend.

MARINE...

Northwest flow holds today which will sustain breezy conditions across Lake Huron. Gusts ranging between 20 to 25 knots are expected. Ongoing lake effect rain bands will also continue across the southern Lake Huron basin through the day. The Small Craft Advisories remain in effect from the outer Saginaw Bay to Port Huron, aligned where elevated wave heights reside. An isolated waterspout cannot be ruled out with any stronger rain shower. High pressure to then build in over the Great Lakes starting tomorrow. This will end lake effect precipitation across southern Lake Huron by the afternoon as wind speeds decrease. The influence of high pressure will bring an extended period of dry weather through the midweek period along with lighter winds.

DTX WATCHES/WARNINGS/ADVISORIES

MI...None. Lake Huron...Small Craft Advisory until 10 AM EST Sunday for LHZ421-441>443.

Small Craft Advisory until 7 AM EST this morning for LHZ422.

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