093
FXUS63 KDTX 142344
AFDDTX

Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
744 PM EDT Mon Jul 14 2025

.KEY MESSAGES...

- Filtered sunshine this evening as Canadian wildfire smoke lingers
  overhead.

- Sunny and warm Tuesday with temperatures around 90 degrees and
  heat indices in the low 90s.

- Shower and thunderstorm chances Wednesday and Thursday with
  potential for heavy rainfall.

- A cold front sweeps through the area early Friday followed by
  cooler and less humid air next weekend.

&&

.AVIATION...

Predominately VFR conditions are expected through this TAF period
with minimal clouds and light winds. West winds this evening become
variable tonight as high pressure moves directly over southeast
Michigan before turning southerly tomorrow. Main item of note
remains the presence of wild fire smoke in the air that is bringing
occasional periods of MVFR haze. Some models want to develop areas
of fog or patchy fog across parts of southeast Michigan tonight.
Current thoughts favor a lower probability given the high dewpoint
depression forecast. Will leave out for now, but will monitor trends
overnight.

For DTW/D21 Convection...No thunderstorms expected this TAF period.

THRESHOLD PROBABILITIES...

* None.

&&

.PREV DISCUSSION...
Issued at 326 PM EDT Mon Jul 14 2025

DISCUSSION...

Dry and stable conditions have become established over SE Michigan
today, with the 14.12z KDTX RAOB sampling PWAT values of 0.59" and
dewpoint depressions of over 40 C in the 700-600mb layer. Clear
skies continue through the evening, albeit with filtered sunshine as
a thin layer of Canadian wildfire smoke remains trapped in the sub-
inversion layer. This has muted the diurnal temperature response,
capping daytime highs in the mid-80s which falls short a few degrees
of nearly all model guidance. Varying degrees of surface visibility
reductions have been observed throughout the day as well, with this
transient nature expected through the rest of the evening.

Persistence of the surface high and ridging aloft ensure similar
conditions on Tuesday, while the subsidence inversion caps chances
of convection during the daytime hours. Modest thickness advection
tonight and Tuesday morning along with departing wildfire smoke
afford a few degree temperature boost to bring daytime highs toward
90 degrees under plenty of solar insolation. The surface high is
projected to track right overhead on Tuesday, with divergent surface
flow keeping Gulf moisture (70+ degree dewpoints) well south in the
Ohio Valley. Thus humidity is not expected to raise heat indices
beyond the low 90s.

Pattern shift then begins early Wednesday morning as a vort max/cut
off low lifts into the Ohio Valley along the left exit region of a
25-30 knot 500mb speed max. This lifts a warm front north of the
state line Wed morning which quickly brings dewpoints into the low
70s, MLCAPE values toward 1500 J/kg, and PWAT values near 2.0
inches. Multiple synoptic scale forcing mechanisms will be in play
Wednesday and Thursday to engage the moisture-rich/unstable airmass,
beginning with the southern stream shortwave that shears east into
western Lake Erie early Wednesday morning. Moisture with this
feature is expected to shear east quickly during the morning, and
should allow for at least pockets of sunshine during the first half
of the day Wednesday. Pending this clearing, forecast soundings show
no issue with surface temperatures reaching convective temps by mid-
day to support increasing coverage of pop up showers and
thunderstorms during the peak heating cycle Wednesday. Low
confidence in organized storm potential during the afternoon due to
lack of column flow, but this will be supportive for slow-moving
storms (< 20 mph) that will be conducive for heavy rainfall
especially considering the thermodynamic profiles in place.

Mid-level flow and synoptic forcing then increase Wednesday night
and Thursday as a series of low amplitude shortwaves ripple ahead of
the incoming cold front. This provides a more focused window for
organized thunderstorm potential, but with low confidence as these
types of setups are usually heavily influenced by diabatic heating
and storm/mesoscale boundaries. A cold front eventually sweeps
through the region early Friday, which brings temperatures back
into the mid 80s for the weekend.

MARINE...

Light, mostly southerly winds, the through mid week period will
support warm temperatures and increasing moisture. The next chance
for showers and thunderstorms will enter Wednesday through early
Friday as a series of upper-level disturbances and cold front pass
over the Great Lakes. This brings the chance for some localized
stronger wind gusts with any thunderstorm development, but otherwise
winds remain light given the weaker pressure gradient in place.

&&

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

$$

AVIATION.....AA
DISCUSSION...MV
MARINE.......SF


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