285
FXUS63 KDTX 241956
AFDDTX

Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
356 PM EDT Sat May 24 2025

.KEY MESSAGES...

- A few sprinkles with perhaps a couple isolated showers over The
Thumb in store for today and Sunday with gradual warming, into the
low 60s.

- Warming and drying trend continues into Memorial Day and early
next week.

- Chance for more widespread rain arrives Tuesday PM into Wednesday.

&&

.DISCUSSION...

Solid cumulus field development this afternoon under the cool
northwest flow today. This has held temperatures this afternoon
generally in the upper 50s to low 60s. A few very light radar
returns been noted on radar around the Port Huron area. Very
isolated light rain showers/sprinkles remain possible through this
afternoon across the Thumb supported in the cloud bearing layer and
increased low level lapse rates. However, it still may fall as virga
given the dry sub-cloud layer. Low clouds clear tonight though
scattered high clouds may remain. Should be able to cool off quite
well tonight. Forecast low are mostly around 40 degrees with areas
around Detroit more in the mid 40s. Model consensus for dewpoints to
bottom out around 40 degrees as well keeping the threat of
widespread frost relatively low.

A secondary trough will dip out of Ontario and shear out as it
swings across the central and eastern Great Lakes throughout the
day. There may be just enough surface instability and weaker lift to
generate a light shower, similar to today. Convective depths remain
shallow though, so thunder potential will be very limited. PoPs of
less than 20% will remain to highlight the low end potential for
some light rain showers, mainly across the Thumb with the favored
north-northwest flow persisting. Very minimal airmass change
tomorrow will keep temperatures below normal tomorrow in the low to
mid 60s with the lakeshore communities again staying slightly
cooler.

High pressure ridge will build across the region during the early
week bringing dry Memorial Day. Lower level flow remains easterly,
which keeps warm advection limited. The incremental increase in
temperatures carries into Monday with highs approaching or achieving
70 degrees in the afternoon, which remains below the average for
late May. Passing surface high pressure keeps conditions quiet into
Tuesday before the next trough moves across the northern plains and
a southern stream system lifts northward. This will increased
overall moisture quality with diffluence aloft while lower left flow
looks to hold out of the east. Will continue to highlight the chance
PoPs in the extended for Tuesday evening though timing of rainfall
into mid-week may still be refined with future forecasts. Forecast
also points toward daily highs into mid-week that hang around 70
degrees.

&&

.MARINE...

High pressure begins to fill in across the Great Lakes through the
weekend, centering over the region by Monday afternoon. This will
bring lighter winds as well as some extended periods of dry weather,
outside of some stray shower potential. Northwest flow will continue
this weekend, but will veer to the northeast as high pressure
directs itself overhead.

&&

.PREV DISCUSSION...
Issued at 1230 PM EDT Sat May 24 2025

AVIATION...

Cool northwest flow persists this weekend, coupled with moisture
flux from the Great Lakes contributing to low VFR clouds during the
bulk of the daylight hours. Diurnal mixing will raise the boundary
layer, with mid clouds (5+ kft) potentially lingering this evening
before skies mostly clear out. A repeat performance with low VFR
clouds developing tomorrow. A cold pool of air aloft does move in
during the day, which generates some modest capes, which could also
touch of isolated showers.

For DTW/D21 Convection... No thunderstorms today or tonight.

THRESHOLD PROBABILITIES...

* Medium for cigs aob 5000 into the evening, then again tomorrow
  afternoon


&&

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

$$

DISCUSSION...AA
MARINE.......AM
AVIATION.....SF


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