123
FXUS63 KDTX 140752
AFDDTX

Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
352 AM EDT Tue Oct 14 2025

.KEY MESSAGES...

- A dry cold front exits SE Michigan this morning and cooler air is
  slow to arrive until later tonight.

- A low probability (30%) of light rain remains in the forecast late
  tonight and early Wednesday.

- Dry weather and normal mid October temperatures resume Thursday.

- Warmer air but a more active rain pattern is expected Friday
  through this weekend.

&&

.DISCUSSION...

A rain-free cold front slides the rest of the way through SE Mi this
morning ushering in broad surface high pressure from central Canada
this afternoon and tonight. Clear sky and mild air out ahead of the
frontal cloud band set up favorable conditions for fog and stratus
as temperatures radiate down into surface Td ranging from the upper
40s to lower 50s most locations. The northerly wind shift post front
scours out the fog and stratus while model fields show just neutral
to shallow/weak cold advection. The slow advance of cooler air is
balanced by waning mid October daytime heating as clouds clear north
to south across Lower Mi. High temperatures are then able to return
a few degrees above normal, especially toward the Ohio border.

The large area of surface high pressure slides to a position
centered on Lake Superior tonight, close enough to promote stronger
cold advection as post sunset northerly wind continues through the
low levels, but not close enough or deep enough to displace the mid
level frontal zone. The lingering frontal zone keeps a low
probability of light rain in the forecast as a shallowness in the
structure maintains the surface boundary well down in the Ohio
valley while the 850-700 mb theta-e gradient remains west to east
across southern Lower Mi. A subtle mid level short wave and strong
upper jet combination backs the 850-700 mb wind just enough to
produce some destabilizing moisture transport for rain shower
potential late tonight into Wednesday morning. Also notable is a
pronounced dry layer shown in model soundings below 850 mb which the
inbound moisture will struggle to overcome. The model soundings and
plan view QPF support the entry level chance POPs in the going
forecast with no increases planned in this early morning update.
Pockets of saturation produce enough rain to result in wet ground in
scattered locations until the mid level frontal zone is finally
driven south of the area by afternoon. Lingering clouds and
continued low level cold advection then hold afternoon temperatures
in the upper 50s to lower 60s which sets up chilly/frosty conditions
as sky clears Wednesday night. Guidance low temperatures are solidly
in the mid 30s by sunrise Thursday.

Amplifying larger scale split flow in the mid to upper levels
continues during the late week and into the weekend. The closed low
moving into the Pacific coast today helps build a southern stream
500 mb ridge over the central States and surface high pressure
across the central Great Lakes by Thursday. Consensus of
deterministic model solutions maintains dry weather for SE Mi
Thursday and Thursday night leading into a transition day Friday.
The southern stream Rockies closed low opens up into the Plains and
central Canada while producing a large and well-organized surface
low pressure system projected to move through northern Ontario and
the Great Lakes. The system brings a pronounced warming trend and an
active precipitation pattern to SE Mi this weekend.

&&

.MARINE...

Northwest winds will gradually increase today as colder air slowly
filters into the region. The coldest air will arrive early Wednesday
morning, as 850 MB temps drop into the low to mid single numbers.
Winds will be out of the northeast at this time as large high
pressure builds through the northern Great Lakes. With northerly
sustained winds around 20 knots Tuesday night, the prolonged long
fetch will likely be enough to build waves at or above 4 feet over
the southern Lake Huron Basin. Winds to then become light and
variable to end the work week as the high pressure system becomes
fully entrenched.

&&

.PREV DISCUSSION...
Issued at 1140 PM EDT Mon Oct 13 2025

AVIATION...

Sufficient window of open late tonight outside of MBS will again
bring potential for some areas of fog and/or very low stratus during
the pre-dawn hours. Less favorable conditions than recent nights as
low level flow no longer carries an added boost off the lakes, so
confidence in occurrence at any one location remains quite low.
Forecast will continue to highlight a window between 09z and 13z for
some reduction of visibility. A cold front on pace to sag across the
region Tuesday. Narrow axis of moisture will accompany this
boundary, bringing increasing potential for some thicker higher
based VFR at times. Light/variable winds overnight emerging from the
north with modest speed Tuesday.

For DTW/D21 Convection...No thunderstorms through the taf period.

DTW THRESHOLD PROBABILITIES...

*  Low for visibilities aob 1/2 sm or ceilings aob 200 ft early
   Tuesday morning.

*  Low for cigs at or below 5000 ft Tuesday afternoon.


&&

.DTX WATCHES/WARNINGS/ADVISORIES...

MI...None.

Lake Huron...Small Craft Advisory from 2 PM this afternoon to 5 PM EDT Wednesday
     for LHZ421-441.

     Small Craft Advisory from 5 PM this afternoon to 5 PM EDT Wednesday
     for LHZ442-443.

Lake St Clair...None.

Michigan waters of Lake Erie...None.

&&

$$

DISCUSSION...BT
MARINE.......SF
AVIATION.....MR


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