791
FXUS63 KDTX 301937
AFDDTX

Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
337 PM EDT Mon Jun 30 2025

.KEY MESSAGES...

- Showers and thunderstorms are likely to continue through the late
afternoon. There remains a Marginal Risk (1 out of 5) for severe
weather until around 7pm across all of Southeast Michigan. The most
likely threats will be damaging wind gusts to 60 mph and flooding
due to torrential rainfall rates.

- Classic summer weather pattern during the middle to end of the
week with daytime temperatures hovering in the low to mid into the
80s.

&&

.DISCUSSION...

Another day featuring high CAPE (pushing 3000 J/kg per SPC
mesoanalysis) and low shear (generally around 20 knots) in a very
moist environment with surface dewpoints into the low 70s and PWATs
exceeding 1.7 inches. Early day clouds helped prevent some
destabilization locally, but clearer skies over SW lower lead to
rapid destabilization in the vicinity of a prefrontal trough which
quickly lead to a line of showers and thunderstorms developing. A
mid level pocket of dry air sliding over is also to steepen mid
level lapse rates helping some storms to get a little better
organized. As we move through the late afternoon and evening, the
current line of convection will continue eastward with
isolated/scattered storms developing ahead of it. Isolated cells may
become strong to severe with pulse type storms producing wet
microbursts. So far majority of the storms have struggled to produce
winds over 30 knots. These storms are also slow moving tracking
eastward around 20 mph so heavy rain and localized flooding will
also be a concern. Bulk of the activity will come to an end between
5-7pm today with a few isolated showers/storms possibly lingering
until the surface cold front pushes through after 8pm.

Longwave trough axis swing through tonight into Tuesday morning.
Models try to keep some POPs going through the night along the lead
edge of the trough but there isn`t much support for additional
activity with instability trending toward zero and synoptic forcing
lacking. Will trend POPs down to slight chance for now to give a
chance to see the trough upstream and whether its carrying any
showers with it.

Rest of the week gets quieter as the ridge starts building back
through the Plains and sliding eastward through the Mid MS Valley.
We`ll largely be in northwesterly flow through the week with a few
waves tracking through Canada trying to send some fronts into the
region. So can`t rule out a few showers through the week but will
take a more notable system like on Sunday to bring more widespread
POPs to the region.

&&

.MARINE...

A cold front brings scattered showers and thunderstorms through the
afternoon with activity gradually winding down tonight as the front
clears the area. Light south wind shifts to westerly behind the
front, peaking at 15 to 20 kt on Tuesday afternoon. High pressure
over the Midwest maintains prevailing westerly wind over the Great
Lakes through mid-week. A weak cold front sinks across the area late
Wednesday into Thursday with post-frontal northwest wind likely to
remain light. High pressure builds across the region on Friday to
provide light wind and waves.

&&

.PREV DISCUSSION...
Issued at 1205 PM EDT Mon Jun 30 2025

AVIATION...

An influx of low and mid level moisture this morning has led to a
wide array in ceilings heights across Se Mi, with the metro Detroit
terminals experiencing periods of MVFR based ceilings. The gradual
departure of the higher cloud deck is opening the door to rapid
destabilization across Se Mi. This within a moist and uncapped
environment has led to numerous thunderstorms across wrn Lower Mi,
which will slowly develop and advance across Se Mi during the early
portion of the afternoon. Given the ongoing early convective
release, the probabilities of thunderstorms beyond 21Z is less
probable and will be left out of the TAFs. Given the potential
afternoon convection and abundant low level moisture, some degree of
low clouds may linger into the early evening hours before a little
bit of low level dry air advection clears them out.

For DTW/D21 Convection...The departure of the thicker morning cloud
cover is now driving the region of better instability into the metro
airspace. The combination of convective development and upstream
convection moving into the airspace will likely support scattered to
numerous thunderstorms through at least 20 or 21Z. The afternoon
convective release will make convection after 21-22Z less probable.

THRESHOLD PROBABILITIES...

* Moderate in thunderstorms this afternoon.

* Moderate in ceilings aob 5000 feet this afternoon.


&&

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

$$

DISCUSSION...DRK
MARINE.......TF
AVIATION.....SC


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