Key messages
- The potential exists for dense fog development each of the
Key Messages
daybreak periods Friday through Monday. Any fog that will develop is expected to dissipate or lift by 10 am.
- Mild and dry through the middle of next week.
Aviation
High pressure will maintain residence throughout the region this period as it settles into Quebec. Associated veering of wind toward the northeast and then east with time through Friday morning will set the stage for some degree of low level moisture advection off the upstream lakes tonight. Evidence of this already underway across Sagainw Bay in the form of lower stratus, suggesting a high likelihood for fog/low stratus expansion into portions of central and southeast Michigan throughout the night. Forecast will continue to highlight a window for IFR to LIFR conditions to emerge during the early morning hours. Potential does exist for a period of dense fog to develop, with visibility below 1/4 mile. A gradual improvement in conditions late morning as daytime heating works to lift and clear any lingering low stratus and fog. VFR conditions with a limited diurnal cu production for the remainder of Friday.
D21/DTW Convection... Thunderstorms are not forecast through the TAF period.
Dtw Threshold Probabilities
* Low for cigs/vsby to fall below 200 ft and/or 1/2SM.
Prev Discussion
Issued at 244 PM EDT Thu Oct 22 2026
DISCUSSION...
An anomalous upper level ridge advancing into central sections of far northern Canada will open the door to the rapid amplification of an Omega Block over the central Contiguous United States for the end of the work week. Upper level high pressure will then stall out and impact the forecast area through Monday of next week. Quite the structure with H3 heights reaching 588 dam over portions of the Lower Peninsula this weekend and +13C 850mb temperatures advecting well into Hudson Bay. Ideal mid Autumn conditions with high temperatures reaching the middle to upper 60s, 5 to 10 degrees above normal, and lows falling into the 40s.
The only weather of significance the next few days will be br and fog chances during the daybreak periods. A better setup for fog will be Friday morning with onshore flow advecting a marine airmass inland. The relatively warm lakes will offer higher dewpoints that combined with weak flow will provide for saturation potential. Surface condensation pressure deficits support fog beginning in the tip of the Thumb tonight before expanding southeastward through all of the area. The fog potential for Saturday morning looks to be the greatest near Lake Erie before expanding westward. Could see a scenario where the Detroit urban heat islands remain just warm enough to dissuade the fog formation. Persistent light easterly wind should bring more fog chances Sunday morning. Will likely add areas of fog in the forecast for tonight/Friday morning and maintain the patchy mention this weekend.
Models suggest the amplitude of the omega will shear off or flatten by Monday. Indications are that a weak cold front could push southward invof Southeast Michigan, however, current data suggests a dominance of anticyclonic flow trajectories that will not favor large scale synoptic ascent. Preference is for a dry forecast through next Wednesday.
MARINE...
High pressure influence persists over the central Great Lakes today as a surface ridge begins to build and center over Quebec. Northerly winds veer easterly tonight with speeds generally AOB 10 knots, becoming southeasterly by Friday afternoon/evening. Winds turn southerly into the weekend with a slight uptick in speeds as the stretch of tranquil and mainly dry conditions continue into next week.
Dtx Watches/Warnings/Advisories
MI...None. Lake Huron...None. Lake St Clair...None. Michigan waters of Lake Erie...None.
AVIATION.....MR DISCUSSION...CB MARINE.......KGK
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