895
FXUS63 KDTX 011947
AFDDTX

Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
347 PM EDT Thu Oct 1 2026

.KEY MESSAGES...

- Coverage and intensity of showers increase across SE Michigan
  tonight.

- There is a chance for locally heavy rainfall until showers end with
  the passage of a cold front Friday morning.

- Low temperatures are projected to reach the mid to upper 30s north
  of metro Detroit by Saturday morning.

- Cool temperatures continue through the weekend.

- There is a low chance for a short period of light rain Sunday.

&&

.DISCUSSION...

A broad band of showers spans the central Great Lakes and extends
into the central Plains this afternoon. It is on schedule to migrate
across the rest of SE Mi tonight while gaining intensity along and
near the cold front that is already moving into central Lower Mi at
forecast issuance. The rainband is sharpened by frontogenesis in the
low to mid levels as the mid/upper level trough and jet entrance
region move eastward into a more complementary position that is
reflected in model depictions of notable 850-700 mb theta-e gradient
increase across the frontal zone. The same theta-e projections show
the mature moisture axis also still tapping a hybrid tropical
Pacific/Gulf supply and feeding it into the Great Lakes along and
ahead of the frontal zone. At least a brief period of heavier rain
occurs in this setup as the 12Z DTX sounding measured PW near 1.8
inches and as HREF and REFS mean PW touches 2 inches as the system
moves through SE Mi tonight. Otherwise, the steady NW to SE pace of
the frontal passage limits flooding potential until the pattern
exits early Friday morning.

Expansive surface high pressure settling into the northern Plains
today builds aggressively into the Great Lakes during the day
Friday. It brings an air mass that is cool enough to produce
scattered to broken cumulus during the afternoon which becomes dry
enough for a rapid clearing trend Friday evening. Radiational
cooling then wins out over any lingering light north wind and/or
thin cirrus during the night. Guidance low temperatures in the mid
to upper 30s look good north of metro Detroit by Saturday morning.

The larger scale westerlies stay progressive during the weekend with
a model consensus on the next low pressure system arriving in
northern Ontario Sunday. The trailing cold front might be capable of
a stray shower as it sweeps through the Great Lakes while high
pressure traps Gulf moisture near the coast to mid Atlantic. The
front ushers in a new round of high pressure and below normal
temperatures as the weather highlight for early next week.

&&

.MARINE...

Widespread rain associated with a cold front will slowly push
southward across Lake Huron tonight before exiting southeast of Lake
Erie late Friday morning. Post frontal shallow cold air advection
along the lead edge of expansive high pressure over the northern
Plains will result in increasing north-northwest winds during the
night into Friday. Available guidance suggests moderate to high
probability for wind gusts of 25 to 30 knots across the open waters
of Lake Huron. This will also help drive hazardous conditions to
small craft across the Lake Huron nearshore waters tonight and
Friday. The high pressure system will expand across the Great Lakes
region Friday night into Saturday, resulting in light winds. The
rapid eastward departure of this high by Sunday will drive another
frontal system into the region by the end of the weekend. This front
will be moisture starved and generally weak, limiting weather
conditions to just light rain chances. Its passage will be marked by
a veering of the winds from south to west-northwest. Some uptick in
the winds is expected over Lake Huron within the post frontal cold
air advection. Available guidance indicates the winds remaining
below gales.

&&

.HYDROLOGY...

A large band of showers moves across SE Mi while gaining intensity
with the passage of a cold front tonight. The band has access to a
tropical Pacific and Gulf moisture supply that fuels brief periods
of heavy rain within the more persistent band. There is high
confidence in rainfall totals up to 1 inch and medium confidence in
totals of 1 to 2 inches during a 3 to 9 hour period. The low-end
chance for totals to reach or exceed 2 inches requires a frontal
passage that would be slower than projected at this point in the
forecast. This scenario limits potential flooding to minor instances
in low-lying areas with ponding water on roads across the region
until the rain quickly ends post-front Friday morning.

&&

.PREV DISCUSSION...
Issued at 129 PM EDT Thu Oct 1 2026

AVIATION...

Stream of Gulf moisture ahead of a cold front and passage of this
front will maintain widespread rain across KMBS through the evening
and will increase coverage across all other TAF sites tonight. MVFR
to IFR cigs are expected with the onset of rain showers along with
likewise restrictions to visibility under the more moderate rainfall
intensity. There will be a low chance immediately along the front
for acute stronger rain showers within a 1-3 hour window that can
bring very brief periods of LIFR cigs. Otherwise, winds will quickly
back from southwest to northwest after the passage of the front with
rapid dry air advection bringing quick improvements to ceiling
heights in the wake of the front.

D21/DTW Convection...Low potential for thunderstorms through this
forecast period.

DTW THRESHOLD PROBABILITIES...

* High for ceilings below 5000 feet this evening.

* Low for thunderstorms this evening and overnight.


&&

.DTX WATCHES/WARNINGS/ADVISORIES...

MI...None.

Lake Huron...Small Craft Advisory from 10 PM this evening to 10 PM EDT Friday
     for LHZ421-443.

     Small Craft Advisory from 10 PM this evening to 4 AM EDT Saturday
     for LHZ441-442.

Lake St Clair...None.

Michigan waters of Lake Erie...None.

&&

$$

DISCUSSION...BT
MARINE.......SC
HYDROLOGY....BT
AVIATION.....AM


You can obtain your latest National Weather Service forecasts online
at www.weather.gov/detroit.