550
FXUS63 KDTX 120923
AFDDTX

Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
523 AM EDT Mon May 12 2025

.KEY MESSAGES...

- Above average temperatures persist through the week.

- Scattered showers/thunderstorm chances on Tuesday and Wednesday.

- Greater thunderstorm potential Thursday evening.

&&

.AVIATION...

Surface high pressure gradually vacates in favor of a southern
stream upper low that will slowly dislodge into the Ohio Valley
tonight into Tuesday. Today begins with mostly sunny skies and light
northeast flow, but a gradual increase in high cloud is anticipated
by early evening. Winds remain light and veer toward the southeast
this morning through the end of the TAF period. Ceilings lower
steadily tonight and Tuesday morning amidst shower activity,
comfortably falling below 1000 feet and possibly to or below 500 ft
for a brief period around 12z Tuesday morning. That said, dry low
levels may inhibit the more pessimistic stratus build down scenarios
or at least delay onset. Thus will carry the inherited IFR cigs for
all TAF sites Tuesday morning.

For DTW/D21 Convection... No thunderstorms are expected through the
forecast period.

THRESHOLD PROBABILITIES...

* High in ceilings aob 5000 feet Monday night.

* Low for cigs/vsby to fall below 200 ft and/or 1/2 SM Tuesday
  morning.

&&

.PREV DISCUSSION...
Issued at 402 AM EDT Mon May 12 2025

DISCUSSION...

A dry airmass remains in place today with high degree of dry air
noted at 850mb on the 00Z DTX RAOB, which brings clear skies to
start the day. Quiet weather conditions will hold through the
remainder of the day has upper ridging builds further east over the
region and the main surface high slides off the Atlantic Coast. There
will be a noticeable increase in lower level thermal and moisture
profiles throughout today, which will help drive afternoon
temperatures upward to around 80 degrees for inland areas while the
east-southeasterly flow will keep lakeshore areas cooler.

Tonight will see increasing rain chances as a closed mid level low
begins to drift northward from the gulf states. Vorticity advection
around the northern end of the low with improving theta-e will help
support this initial round of elevated scattered activity late this
evening/tonight. Very limited instability should keep thunder at bay.
Heading into Tuesday and Wednesday, continued waves of vorticity
advection with better moisture quality will support daily rainfall
chances. Greatest coverage each day will more than likely focus
around the diurnal maximum when instability is at its peak. There
will be a chance for isolated to scattered thunderstorms each day,
but the weak lapse rates and weak low-mid level flow that tops out
around 20 knots will be limiting factors preventing a more intense
convective response. Overall cloud cover and scattered rain will keep
daytime high temperatures mostly in the 70s.

The mid-week trough will give way to a much more potent trough
swinging across the Northern Plains and Midwest on Thursday. The
increase in southwest flow will bring temperatures back into the low
80s while dewpoints climb into the 60s. Brief downstream ridging
will also bring keep weather dry for the majority of the day
Thursday. Focus will be on the upstream convective response with
favorable dynamics during the afternoon into the evening. Expect
rain and thunderstorms focused along a line or broken line to drive
across Lake Michigan and western portions of the state before
arriving to southeast Michigan after 8 pm. The overall environment
would be supportive of organized convection upon arrival given the
increased shear with the typical question of available instability
given the late timing. Strong to possibly severe thunderstorms will
be possible should enough instability hold into the night.

A series of front forecast to sweep through Michigan Friday and over
the weekend. Broad brush of PoPs during this period marks the
general uncertainty in exact timing of features that may result in
showers and thunderstorms, which are focused mainly on Friday night
and Saturday. Cooler air will eventually arrives across southeast
Michigan bringing temperatures back to around the average (upper 60s
and lower 70s) for the weekend.

MARINE...

Modest return flow/southeast winds today drawing moisture northward.
Periods of showers and isolated thunderstorms expected to develop
this evening through Wednesday, as a large low pressure system lifts
out of the southern Mississippi River Valley. With the mild nature
of the airmass however, winds outside of any convection will remain
light through the mid week period. A stronger storm system slowly
tracking through the northern Plains to end the work week will
likely trigger additional showers and thunderstorms, some of which
could be strong.

&&

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

$$

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


You can obtain your latest National Weather Service forecasts online
at www.weather.gov/detroit.