602
FXUS63 KDTX 061029
AFDDTX

Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
629 AM EDT Sat Jul 6 2024

.KEY MESSAGES...

- Isolated to widely scattered showers will be possible this
afternoon and evening, generally north of I-94. Some rumbles of
thunder cannot be ruled out.

- The holiday weekend closes out with dry weather Sunday under
partly sunny sky.

- Hot Monday with highs in the upper 80s. Shower and thunderstorm
chances return Monday and Tuesday.

&&

.AVIATION...

LIFR/IFR stratus with some patchy dense fog will settle into the I-
69 corridor and gradually mix to a higher base with time. Another
distinct area of stratus of IFR/lower MVFR cigs is also surging east
into the remainder of the area. This will impact KPTK most, but will
also reach the I-94 corridor with at least MVFR/lower VFR ceilings
at times from mid morning into the afternoon. Will continue to leave
mention of isolated showers out of the forecast, but expect sparse
coverage activity by mid/late afternoon, especially KFNT north. Some
clearing into evening and the overnight should allow for some more
fog development late tonight as winds become calm to light/variable.

For DTW/D21 Convection...Widely scattered showers and a thunderstorm
or two will be possible this afternoon/evening, but best chance will
hold north of KPTK.

DTW THRESHOLD PROBABILITIES...

* Low for thunderstorms this afternoon.

* Medium for ceilings at or below 5000 ft from mid morning into
  the afternoon today.

&&

.PREV DISCUSSION...
Issued at 336 AM EDT Sat Jul 6 2024

DISCUSSION...

A cold front has cleared the state as of early this morning, where
dry weather now prevails in the wake of the front with temperatures
presently in the mid-60s. Residual moisture and humidity will hold
on today across SE MI, which will aid in the production of isolated
to widely scattered shower activity. The inherited forecast looks
reasonable, holding PoP chances north of I-94, with highest PoP
chances (30-35%) located along and north of I-69, tied to the
greater moisture and subsequently better instability.

Instability and bulk shear are not favorable for sustainable
activity today, holding at 500 J/kg and around 15-20 knots
respectively. Additionally, a cap just under h600 will limit
convective depth and coverage. However, steep low level lapse rates
with the passage of multiple upper-level waves do justify the PoP
potential. Cannot rule out some embedded thunderstorms, but LI
values of 0 to 1 and very poor mid-level lapse rates favor rain
showers. Shower and storm potential will wane with the loss of
daytime heating, with lingering potential lasting through 10PM-
Midnight. Highs hold in the upper 70s in the wake of the front.

A weak shortwave ridge will fill in behind the departing shortwave
and will bring a day of dry weather tomorrow with temperatures
returning into the mid 80s for a high. The return of warmer weather
is a result of multiple upper-level waves that fill in over the
Plains with trough amplification taking place across the greater
Plains through the early week period. Initially, this directs heat
and moisture from central US downstream into the Great Lakes noted by
h850 temperatures increasing from 16C Sunday evening to 18C by
Monday evening. This brings daytime highs in the upper 80s, possibly
reaching 90 across urban areas on Monday. Rain and thunderstorm
chances are also possible Monday with the improved moisture and
support from glancing shortwaves ahead of the main trough axis. The
better chances for numerous to widespread showers with embedded
thunderstorms will enter late Monday into Tuesday tied to the better
connection with the trough, with the axis swinging over Michigan late
Tuesday night.

Medium range models are more muddled through the midweek period
given subtleties with shortwave passages and interactions. One major
consideration that models are struggling with this far out will be
the upstream impacts of Tropical Storm Beryl. The latest ECMWF is
much less progressive relative to the 12Z model run and pushes the
system into the Ohio Valley, clipping portions of SE MI. Even less
progressive is the ICON (and ICON-EPS), which pushes the center of
the low right over Michigan. Regardless, not much credence is given
into any one particular model solution at this time factoring in
limited sampling from the upper-air network, but it is worth noting
as several deterministic runs display a much less progressive
solution for the 00 cycle. Closer attention will be given to the path
of the system as it makes landfall somewhere over southeast TX by
early Monday.

MARINE...

Low pressure departs to the eastern Great Lakes this morning but
leaves a trailing trough that lingers over the local area much of
the day. This feature and enough moisture wrapping around the
departing system will keep scattered showers in the forecast with
potential for a few thunderstorms as well. Light northwest winds
develop today at generally 10 knots or below. The trough exits
tonight with weak high pressure moving back in through Sunday
bringing continued light winds. Southerly wind of 10 to 15 knots
then develops on Monday ahead of the next frontal system moving in
from the Midwest. This system will bring showers and storms late
Monday into Tuesday as it tracks through. Slightly cooler northerly
flow follows for the mid-week.

&&

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

$$

AVIATION.....DG
DISCUSSION...AM
MARINE.......TF


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