Expert Forecast Opinion

563
FXUS63 KDTX 051917
AFDDTX

Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
317 PM EDT Fri Jun 5 2026

.KEY MESSAGES...

- Periods of showers with potential for a few embedded thunderstorms
until late tonight.

- Additional showers and storms possible Saturday with isolated
strong to severe storms possible, capable of producing marginally
damaging wind and large hail.

- Heat builds next week with reoccurring periods of thunderstorms.

&&

.DISCUSSION...

After an 8+ day stretch of rain-free weather, showers are lifting
across Southeast Michigan. Confluent low-level winds have
transported Gulf moisture up through The Plains and into Lower
Michigan, while ThetaE advection has been even more aggressive
within the mid-levels. This has raised PWATs from less than 0.50
inches this morning to over an inch, and PWATs should exceed 1.50
inches by this evening. Expectation for convective evolution is that
showers should largely be void of thunder through the rest of today
given lackluster instability. Latest SPC Mesoanalysis Viewer shows
an axis of +500 J/kg SBCAPE extending across central Lower, but the
ongoing convective showers are rooted eastward, along the gradient.
Some uncertainty remains as to how quickly this activity moves east
through the rest of the forecast area this evening, before losing a
surface-based mixing connection. Should evening convection deepen to
produce thunder, the severe threat would be low. Inverted-V
soundings with DCAPE in excess of 750 J/kg support an isolated gusty
wind threat along the unmodified lead edge, limited by displacement
from the instability reservoir. Weak mid-level cooling after dark
should offer a bit of elevated nocturnal instability for a few
rumbles of thunder prior to midnight. Rising dewpoints lead to a
warmer night, with lows only cooling into the mid-upper 60s.

Showers should generally be dissipating early Saturday morning as
the lead shortwave moves east of the area, but the lull gives way to
another opportunity for convection late Saturday morning and midday.
Coverage of thunder carries a high degree of uncertainty, even as
the track of a secondary mid-level trough digs cleanly through Lower
Michigan. Distinct increase in instability is probable Saturday as
dewpoints rise into the upper 60s with positive buoyancy lifting
above 1000 J/kg, paired with EBS of 25-35 knots. Ascent will be
boosted by an inbound could front draped across the Great Lakes.
Main convective threats should be water-loaded microbursts/winds and
possibly some stray larger hailstones. Convection dissipates quickly
in the wake of the front Saturday evening as stabilization settles
in. Surface high pressure over the northern Great Lakes leads to
veering northerly flow and minor surface-layer cooling/drying on
Sunday. Geopotential heights rise overhead Sunday while a cut-off
low lifts northward from the eastern Plains, into the Upper Midwest.
Precipitation with this wave should remain just west of the region,
ensuring a dry Sunday forecast, locally.

The main two concerns for next week week will be Tuesday convection
and then heat the rest of the week. A Pacific longwave trough nudges
the orphaned cyclonic wave into Lower Michigan while anomalous
moisture transport spills in from the southwest. This supports a
high-CAPE low-shear convective environment. With dewpoints
approaching 70F, strong to severe storms may arise Tuesday. By mid-
week, a 590+ dam 500 mb ridge will extend from Baja California to
Ontario which would allow for highs in the 90s. Given persistent
humidity, potential exists for heat indices to approach 100F, which
would raise concern for heat headlines.

&&

.MARINE...

Warm southerly winds topping out around 20 knots this afternoon are
advecting moisture, with showers moving through the central Great
Lakes. A surface low tracking through the central Great Lakes this
evening will bring a renewed round of numerous showers and a few
thunderstorms to the region, persisting into the night. Light,
mostly westerly winds on Saturday. A weak cold front will sink
southward late in the day, serving as the focal point for scattered,
potentially marginally severe thunderstorms, with the highest
probability over Lake St. Clair and Lake Erie. Very light northeast
flow and dry conditions will follow for Saturday night and Sunday.
Warm and humid weather returns early next week, bringing showers and
thunderstorms on Tuesday. An upper level ridge will become
reestablished for the mid week period, resulting in mainly light
winds and and hot temperatures through the end of the work week.

&&

.PREV DISCUSSION...
Issued at 139 PM EDT Fri Jun 5 2026

AVIATION...

A series of upper air disturbances will work across Lower MI this
evening into tonight, with a core of 35-40 kt southwest winds aloft
providing focused moisture transport. Scattered to numerous showers
with embedded thunderstorms will continue to spread into the area at
the nose of this moisture transport, first across Mid MI and the
Thumb this afternoon then expanding south and east toward Metro
Detroit this evening. Isolated stronger storms may produce gusts in
excess of 40 kt. Ceilings will lower toward MVFR mid to late evening
and persist into Saturday morning. The highest coverage of
convection is generally anticipated between 6PM and 2AM, though
elevated instability brings potential for another round of showers
and storms into early Saturday morning - opted to add a TEMPO group
after midnight to include this. Convective trends from late Saturday
morning into the afternoon carry higher uncertainty, but lingering
instability will bring the potential for scattered convection as a
weak cold front sinks south.

D21/DTW Convection...Showers are forecast to reach the vicinity by
23 to 00z this evening. Confidence in thunder is low to moderate
through midnight. A second window for convection appears centered
between 06 and 09z overnight with slightly higher probability for
thunder.

DTW THRESHOLD PROBABILITIES...

* Moderate for thunderstorms tonight, mainly after midnight.

* Moderate for ceiling 5000 ft or less this afternoon and tonight.


&&

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

$$

DISCUSSION...KGK
MARINE.......SF
AVIATION.....TF


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at www.weather.gov/detroit.