953
FXUS63 KDTX 121724
AFDDTX

Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
124 PM EDT Sat Sep 12 2026

.KEY MESSAGES...

- Isolated showers still possible this afternoon, with scattered
  showers developing Sunday late afternoon primarily north of I-69.

- Cool Sunday Night: Low temperatures fall into the 40s Sunday night
  as high pressure and cooler air settles over the area.

- Unsettled Midweek: Warmer and humid conditions return early next
  week, bringing multiple waves of of showers and thunderstorms
  Tuesday through Thursday.

&&

.AVIATION...

Cloud canopy from thunderstorms over Ohio has overspread the Detroit
airspace terminals.  Additional low-level moisture filtering in from
the Lake Erie marine layer is supporting some periodic MVFR clouds,
as well.  A few light showers have come and gone with the. increased
boundary layer moistening. Expecting differential heating along the
cloud edge to support some late afternoon widely scattered
convective activity. The best corridor will be along the highlands
north of Detroit - but may affect parts of the arrival airspace into
DTW. Coverage will be limited and short-lived. Surface winds will
gain a gust component at MBS and FNT as the mixed layer grows better
under meaningful sunshine.

Ribbon of MVFR clouds along an approaching cold front will crawl in
overnight - especially at the northern terminals. As the front
filters through, winds will flip to light north-northeast prior to
daybreak.  Clouds will lift and scatter out Sunday morning as drier
air filters in near the surface.

D21/DTW Convection...A very low chance for an isolated thunderstorm
within D21 will be monitored for potential to affect the DTW
airspace this afternoon and evening.

.DTW THRESHOLD PROBABILITIES...

* Moderate for ceiling 5000 ft or less today and tonight.

* Low for a thunderstorm this afternoon and evening.

&&

.PREV DISCUSSION...
Issued at 256 AM EDT Sat Sep 12 2026

DISCUSSION...

A well-defined shortwave tracking into western Kentucky/Tennessee
will be opening up and absorbed by the northern stream trough
tracking through the western Great Lakes. Just enough moisture
advection and weak forcing will track into the southeastern half of
the CWA today, along with enough destabilization (slightly negative
LI`s and SBcapes of 500-750 J/kg) to support the potential for
isolated showers and possibly a stray thunderstorm. A secondary
moisture axis out ahead of a cold front will also track in from the
western Great Lakes late in the day, passing through during the
evening or washing out altogether. This will provide a secondary
focus for showers, but mostly over Lake Huron.

A deep 500 MB low over Hudson Bay on Sunday will direct a strong
shortwave through the Straights. Timing is now in sync in with the
peak heating of the day, and scattered showers seem likely north of
I-69, closest to the mid level cold pool and moisture enhancement
from Saginaw Bay. 850 MB temps dropping into the mid single numbers
Sunday night will bring mins in the 40s as high pressure builds over
the region. Low level flow looks to be mostly offshore Sunday night
into Monday, but airmass is cold enough to potentially generate some
lake effect showers which could graze the far eastern Huron and
Sanilac counties before the tail of the upper level PV exits east and
good subsidence kicks in.

A strong storm system will track through the northern Plains on
Monday and into northwest Ontario Monday night. The active warm
front is expected to reside over western Great Lakes. Warm and moist
air will eject out of the southern Plains and fold over into Lower
Michigan on Tuesday, as PW value reach around 2 inches. With showers
and embedded thunderstorms likely developing during the day, max
temperatures will likely be hindered and capped in the lower 80s.
There is still some potential for the timing of FROPA to change
slightly, however.

Medium range models continue to hang the front near the southern
Michigan border before returning as a warm front Wednesday night and
Thursday. Euro ensembles offer up a 40-50 percent chance for 24 hour
qpf to reach or exceed half an inch.

MARINE...

High pressure will continue to bring benign marine conditions to the
region through Saturday before unsettled weather comes back in to
finish out the weekend. An active pattern returns late Saturday into
Sunday as a low pressure lifts thought northern Ontario, dragging a
cold front across the area in the morning. Overnight/early day
arrival and detachment from the parent low greatly limit any shower
and storm chances. Moderate trailing northwest flow develops over
northern Lake Huron during the daytime on Sunday with peak gusts
between 25-30kts. This front looks to stall somewhere near southern
Lake Huron offering an isolated shower chance into Monday. A more
dynamic system then lifts out of the Plains and over the northern
Great Lakes Monday night into Tuesday. Preceding warm, humid airmass
will fuel better scattered storm chances during this time.

&&

.DTX WATCHES/WARNINGS/ADVISORIES...
MI...None.
Lake Huron...None.
Lake St Clair...None.
Michigan waters of Lake Erie...None.
&&

$$

AVIATION.....Mann
DISCUSSION...SF
MARINE.......SS/KDK


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