Expert Forecast Opinion

970
FXUS63 KDTX 112348
AFDDTX

Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
748 PM EDT Fri Jul 11 2025

.KEY MESSAGES...

- Chance of thunderstorms remains this evening as a warm front lifts
through the region.

- Increasing potential for showers and thunderstorms Saturday which could
produce isolated severe storms and localized heavy rainfall.

- Warmer summertime pattern underway which will continue into next
week today, continuing through midweek as humidity rises and heat
indices hover around 90.

- Drier weather expected Sunday through midweek as high pressure
moves over the area.

&&

.AVIATION...

Shower and thunderstorm activity will push east of most terminals by
00Z, so have removed TSRA TEMPO groups with this issuance with the
exception of PTK. Bulk of hi-res models will keep southeast Michigan
dry through tonight. There does remain a chance for a few scattered
showers to develop along the warm front tonight, but probability
looks too low to keep mention in TAFs. VFR skies should then hold
through bulk of the tonight period with southeast Michigan in the
warm sector. Wind holds generally out of the south below 10 knots.
Tomorrow will see increasing southwest flow with gusts to around 20
knots by the afternoon. Advancing cold front will produce increasing
coverage of showers and strong to severe thunderstorm, possibly by
early afternoon.

For DTW/D21 Convection... Bulk of thunderstorm activity as held
north of DTW toward PTK and look to stay north. Thus, better
thunderstorm chance has mostly ended. Best chance for strong to
severe thunderstorms will be tomorrow afternoon as a cold front
approaches from the west. Current timing starts around 20Z, but
adjustments will certainly be possible.

THRESHOLD PROBABILITIES...

* Low for ceiling 5000 ft or less outside of thunderstorms.

* Medium for thunderstorms tomorrow afternoon.

&&

.PREV DISCUSSION...
Issued at 346 PM EDT Fri Jul 11 2025

DISCUSSION...

Remnants of last nights elevated MCV still working through SE MI
this afternoon with a bit of an uptick in convection as the surface
warm front lifts up through the region. There is still a chance to
build some instability once this moves through this evening but
chances decrease as subsidence in the wake of the MCV should help
minimize coverage of new development. We`ll keep the current chance
pop going as the clearing upstream is already allowing a bubble of
SBCAPE in excess of 2000 J/kg to build and the nose of the 850mb low
level starts pushing into SW lower. Shear will remain fairly weak,
around 20 knots, so storms should struggle to get too organized but
an isolated storm or two may become strong to severe. Damaging
downbursts winds would be the biggest threat with heavy downpours
also a concern as dewpoints are rising into the 70s behind the
lifting warm front and PWATs are up around 1.75 inches. We remain in
a Marginal Risk for severe weather today.

Better chance for strong to severe storms comes Saturday as a
northern stream trough moves into the Midwest and pulls the stalled
shortwave over IA rapidly northeastward tonight through the northern
Great Lakes with the trailing cold front draped just west of Lake
MI. This puts us solidly in the warm sector tonight into Saturday
with southwesterly flow through that time. There will be a chance of
isolated showers/storms tonight with highest chance up across Mid MI
with a leading edge of the theta e gradient. Rest of SE MI should be
fairly quiet.

On Saturday there is a Slight Risk of severe weather per SPCDY2. The
main trough axis approaches toward morning with the increasing low
level jet pushing a weak shortwave up through SW MI which in turn
pulls up a secondary warm front/theta e surge. Strong WAA will bring
temps to near 90 with dewpoints into the 70s ahead of the cold front
which looks to sweep through the area during peak heating in the
evening. Most CAMs suggest initiation around 18Z with the frontal
line of convection pushing through by about 00Z. SBCAPE will rise to
around 2500 J/kg with shear remaining on the lower side around 25
knots but could reach up to around 30, sufficient to help storms
organize. Wind still looks to be the main threat with these storms,
with hail and heavy rain additional threats. Still cannot rule out a
tornadic threat with the warm fronts in the area.

Quieter weather to end the weekend Sunday as mid level trough lies
over the region and high pressure starts building in. Cold front
could get hung up over far eastern lower MI which could spark a few
showers Sunday, but most of SE MI will remain dry. Nearly zonal flow
with a slight broad mid level ridge builds over the region to start
the week with the next chance of storms targeting the area on
Wednesday as the next trough arrives.

MARINE...

A weak area of high pressure will continue to promote lighter winds
through the remainder of the day. Scattered to numerous showers with
some embedded thunderstorms remain possible through the afternoon
and evening, which brings the chance to see some embedded stronger
wind gusts. Additional chances for showers and thunderstorms will re-
enter Saturday into Sunday ahead of and along a cold front, which
brings additional chances for strong to severe thunderstorm
development capable of producing wind gusts aoa 35 knots. Winds veer
from southeast to southwest through tonight into tomorrow, with
continued veering to the west after the passage of the front. Dry
conditions return in the wake of the front.

&&

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

$$

AVIATION.....AA
DISCUSSION...DRK
MARINE.......AM


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