049
FXUS63 KDTX 141720
AFDDTX

Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
120 PM EDT Tue Jul 14 2026

.KEY MESSAGES...

- Peak heat expected today with highs in the upper 90s and heat
indices near or above 100 degrees. A Heat Advisory is in effect for
all of Southeast Michigan between Noon and 8pm.

- Hot conditions will exist again on Wednesday with heat indices
approaching 100 degrees. The warmest of conditions is expected south
of I 69. A Heat Advisory may again be needed for portions of the
area Wednesday.

- Potential for showers and thunderstorms exists late in the week
into next weekend.

&&

.AVIATION...

High pressure remains in place today confining cloud cover to
passing cirrus. Modest westerly winds this afternoon with peak gusts
between 15-20kts. Wildfire smoke over northern MI is forecast to
start expanding south into SE MI at the very end of the current
period so haven`t included mention in this TAF update.

D21/DTW Convection... There is a low chance for an isolated
thunderstorm Wednesday evening after roughly 22Z.

.DTW THRESHOLD PROBABILITIES...

* Low for thunderstorms Wednesday evening.

&&

.PREV DISCUSSION...
Issued at 258 AM EDT Tue Jul 14 2026

DISCUSSION...

Clean mid to upper level ridging in place across all of the Great
Lakes region with nary a reflectivity return from surrounding
radars. The combination of high static stability in the lowest 10.0
kft agl and relative humidity at less than 10% at the base of the
steeper lapse rates aloft has resulted in little cloud outside of
some patches of cirrus. Modeled vorticity fields and height charts
show the centroid of the ridge elongating and pivoting directly
through Southeast Michigan today. Outstanding absolute anticyclonic
vorticity dipole set to move through indicative of strong active
subsidence. Model soundings show significant additional warming
between 3.0 to 9.0 kft agl this morning with a lowering of the
capping inversion this afternoon. All dynamical processes support the
hottest day this week with highs today making a run at 100 degrees.
Humidity in a relative sense will be lower, but it is important to
stress that surface dewpoints will still be in the 60s. A Heat
Advisory is in effect today between noon and 8pm and any duration of
heat indices reaching 105 degrees is expected to be at less than 3
hours.

Forecast data supports temperatures settling into the lower to
middle 70s tonight. As a result will allow the Heat Advisory to fall
off this evening and make additional decisions on a day to day
basis. Broad long wavelength troughing is expected to evolve over
northeastern North America by the daylight hours on Wednesday with
some semblances that upper level jet axis will push into northern
portions of the Lake Huron basin. This change in curvature in
trajectories is usually adequate in inducing a backdoor front off
the Great Lakes. Thetae fields show the sharp low column baroclinic
zone pushing in and stalling over northern portions of the forecast
area between 15-18z. Notable item for Wednesday is that with the
frontal zone in proximity, NBM guidance has surface dewpoints rising
into the lower 70s for the southern cwa, the same areas that are
still eclipsed by the compressed heat dome/ava signal. Anticipating
additional heat headlines south of I 69 Wednesday. Nocturnal release
of the marine layer should help usher in lower dewpoints for areas
south of Detroit Wednesday night.

Very warm conditions are expected to persist through the end of the
week with daytime temperatures ranging in the 80s in the Thumb to
the lower 90s across the southwest forecast area. Current thought is
that heat indices for the warmest locations should hold below 100
degrees Thursday and Friday.

Upper level northwest flow will carve out a deeper atmospheric
frontal axis in vicinity of Southeast Michigan and the Great Lakes
this weekend. Jet entrance region dynamics sliding into the upper
Great Lakes should lead to synoptic scale lift and precipitation
chances beginning this weekend. Difficult to time onset and duration
of precipitation periods with details highly dependent on thunderstorm
complex tracking.

MARINE...

A hot airmass (850 mb temps in the mid-twenties) will be in place
today over the Central Great Lakes, leading to stable low level
profiles. This should hold the max westerly winds in the 20 to 25
knot range, with the highest winds across northern third of Lake
Huron due to the channeling through the straits. A mainly dry
backdoor cold front dropping south Tuesday night into Wednesday will
allow winds to veer to the northwest behind the front, but still
only topping out around 20 knots Wednesday evening over the north
half of Lake Huron. Northwest winds at or below 20 knots holds on
Thursday. The forecast on Friday and Saturday unravels due to
conflicting model guidance regarding the location and magnitude of a
surface low moving through the Great Lakes region. This has
significant impact not only on wind speeds, but also on wind
direction, along with bringing chances of showers and thunderstorms.

&&

.DTX WATCHES/WARNINGS/ADVISORIES...
MI...Heat Advisory until 8 PM EDT Wednesday for MIZ047>049-053>055-
     060>063-068>070-075-076-082-083.

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

$$

AVIATION.....KDK
DISCUSSION...CB
MARINE.......SF


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