Ann Arbor, Michigan 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

484
FXUS63 KDTX 242305
AFDDTX

Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
705 PM EDT Fri Jul 24 2026

.KEY MESSAGES...

- Dry conditions with near normal temperatures through Saturday.

- Heat and humidity build back into the region Sunday-Monday with
  highs around 90 degrees and heat indices in the low to mid 90s.

- Isolated strong to severe thunderstorms are possible Sunday, with a
  more organized strong to severe weather threat looking to arrive
  Monday.

&&

.AVIATION...

The western fringe of Atlantic coast high pressure holds over SE Mi
tonight. Calm to light southerly wind and clear sky are the results
after daytime fair weather cumulus fully dissipate this evening.

The next low pressure system organizing in the Plains states nudges
high pressure farther east during Saturday. There is a slight uptick
in SW wind between the systems across Lower Mi along with another
round of fair weather cumulus in the afternoon. The afternoon cloud
pattern develops into broken coverage above 5000 ft as cloud
moisture increases Saturday evening.

D21/DTW Convection...No thunderstorms forecast.

.DTW THRESHOLD PROBABILITIES...

* None.

&&

.PREV DISCUSSION...
Issued at 310 PM EDT Fri Jul 24 2026

DISCUSSION...

Another pleasant day today as surface high pressure remains centered
over the central Great Lakes with most areas seeing highs around 80.
Skies clear again overnight with the loss of diurnal cu allowing
lows again to fall towards the mid-upper 50s. Surface ridge axis
shifts over southern Ontario Saturday setting up light southwesterly
low level return flow pushing temps back around late July averages
in the mid 80s. This shift also marks the expansion of broad central
CONUS mid-level ridging into the far western Great Lakes setting the
stage for a more active close of the weekend locally as a series of
ridge riding shortwaves drop into the region.

First of these waves sweeps across lower MI Saturday evening with no
fanfare given the resident dry airmass. Its passage however does
begin to fold in a piece of the richer theta-e airmass over the
upper Midwest with gradual advection top-down in the column over the
course of Saturday night. Lower level moisture looks to become
established by early Sunday morning, coinciding with the arrival of
the second wave, supporting scattered shower chances, particularly
over the Saginaw Valley who reside under the left exit region of the
upper Midwestern jet streak. A few embedded thunderstorms not out of
the question as several J/kg of elevated instability accompany this
moisture advection. This activity wanes by midday Sunday as the wave
reaches Lake Erie/northern OH leading more importantly to a window
for afternoon destabilization ahead of the next wave reaching the
area in the evening. While SE MI is only under the edge of SPC`s Day
3 marginal currently, this shortwave shouldn`t be discounted with
current mid-range model solutions all advertising an arrival in the
~21-00Z timeframe (NAM is a touch later towards 03Z). Favorable
timing within the diurnal window would support MLCAPE values between
1000-1300 J/kg with bulk shear around 35-40kts. The main potential
limiting factor, seen best in the 12Z RRFS, is a more robust morning
convective scenario resulting in stronger trailing
subsidence/capping that any evening convection would need to
overcome first.

Some lingering showers/storms are possible to start Monday morning
though the main convective chances come late Monday as the next wave
reaches the western Great Lakes. Timing window is more muddled as
model solutions range from late Monday afternoon (Canadian/NAM) to
Monday night (GFS/ECMWF). That said, this system brings the
strongest kinematics of any in the wave train as a mid-level trough
digs into the upper Great Lakes. As such, even in the overnight
arrival scenarios, organized severe convection would be in play (all
of SE MI is under a SPC Day 4 15% risk outlook).

MARINE...

High pressure remains centered over the central Great Lakes this
evening maintaining light southerly winds outside of some shoreline
effects towards Thunder Bay. Influence of said high wanes over the
course of Saturday as a series of systems are set to drop out of the
upper Midwest into the Great Lakes. First chances for a few
thunderstorms arrive late Saturday night-Sunday morning though
greater potential for scattered storms, including a strong to
severe storm, is expected Sunday night.

The next notable storm system arrives on Monday, as low pressure
tracks across the northern Great Lakes. Strong thunderstorms are
possible as the cold front works through the central Great Lakes
during the evening hours. Northerly winds behind this system late
Monday night into Tuesday have the potential to reach 25 knots over
southern Lake Huron.

&&

.DTX WATCHES/WARNINGS/ADVISORIES...

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

&&

$$

AVIATION.....BT
DISCUSSION...KDK
MARINE.......SF/KDK


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at www.weather.gov/detroit.