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103
FXUS63 KDTX 292255
AFDDTX

Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
655 PM EDT Mon Apr 29 2024

.KEY MESSAGES...

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- Dry and slightly cooler Tuesday.

- Well above normal temperatures remain through the week.
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&&

.AVIATION...

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A region of rain extending from KFNT and points east is occurring
within a deep layer moisture plume ahead of a slow moving upper
level trough axis. The back edge of the rain is expected to move
east of Detroit by late evening and will be followed by a weak cold
front, forecast to move across the Se Mi terminals between 06Z and
09Z. There are areas of MVFR based clouds just ahead of this front
which supports model soundings suggestive of increased low cloud
potential during the night. This will be more probable at the
Detroit terminals where the ongoing rain is adding moisture to the
low levels. The passage of the front will usher in a drier airmass
by Tuesday under west winds of 8 to 14 knots.

For DTW/D21 Convection...Very limited instability within the ongoing
region of showers across the airspace will limit the potential for
any thunderstorm. The better chances for TSRA will generally be
across the eastern portions of the airspace (east of Detroit). These
showers will exit east of the airspace between 03Z and 04.

DTW THRESHOLD PROBABILITIES...

* Low in thunderstorms this evening.

* High in ceilings aob 5000 feet tonight. Low on Tuesday.
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.PREV DISCUSSION...
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Issued at 255 PM EDT Mon Apr 29 2024

DISCUSSION...

A brief infusion of deeper moisture affording a modestly unstable
ambient profile late this afternoon. Inbound pre-frontal trough and
850 mb flow greater than 40 knots will continue to capitalize on
this weak buoyancy to produce clusters of showers, with isolated
thunderstorms, over the next several hours. Overall convective vigor
maintains dependence on overcoming generally limited mid level lapse
rates, but potential remains for isolated cells to attain some
updraft depth given the steeper low level lapse rates. As noted in
the AM update, background wind field more than sufficient to offer
organization to any vigorous updrafts. Existing marginal Risk will
continue to highlight stronger wind gust potential, while locally
backed flow across the thumb maintains at least lower potential for
storms to attain rotation and brings a non-zero threat of a brief
tornado within this corridor over the next couple of hours. A
secondary window for sub-severe convection arrives overnight with the
actual cold frontal passage.

Southeast Michigan falls within the immediate post-cold frontal
environment early Tuesday, as height fall emanating south of the
parent circulation exiting into western Ontario expand across lower
Michigan. Ongoing dry air advection affords a steady clearing trend
of early day cloud, maintaining a respectable bounce for the diurnal
temperature curve as improving insolation potential offsets fading
cold air advection during the latter half of the day. This maintains
an airmass characterized by above average temperatures - highs mid
60s to lower 70s. Dry and stable conditions maintained through
Tuesday night under transient low-mid level ridging. Lows in the
40s.

Shortwave energy shearing across the northern great lakes will push
a weak frontal boundary through lower Michigan Wednesday. Brief
window of pre-frontal warm air advection offers a noteworthy uptick
in projected highs Wednesday /well into the 70s/. Pitiful moisture
quality associated with this frontal passage, supporting dry
conditions with simply some increase in cloud. A warm and dry
profile entrenched through Thursday as large scale ridging takes
control. Next round of height falls arrive Friday, as another mid
level circulation pivots from the north-central conus into western
Ontario. Forced ascent featured along the inbound height fall
gradient and attendant cold frontal boundary timed favorably during
peak heating portends a good opportunity for convective development
late Friday.

MARINE...

Weak surface low and associated surface cold front tracking through
the Central Great Lakes late this afternoon. Scattered strong
thunderstorms look to be around for another couple of hours. Will
allow small craft advisories near the tip of the Thumb to expire.
Winds in and around thunderstorms will have potential to produce
wind gusts in the excess of 35 knots however.

Southwest-west winds behind the front tonight into Tuesday morning
will usher in modestly colder air into the region, and wind gusts
should reside mainly below 20 knots, with light and variable winds
then taking over for Tuesday evening as a surface ridge arrives.

Another low pressure system looks to be tracking through Minnesota
and then into Lake Superior on Wednesday, with the cold front
swinging through the Central Great Lakes. Moisture looks lagging,
and the front appears to be weakening in the process. Thus, showers
and moderate winds will be hard to come by, with another surface
ridge then arriving Thursday morning.
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.DTX WATCHES/WARNINGS/ADVISORIES...
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MI...None.
Lake Huron...None.
Lake St Clair...None.
Michigan waters of Lake Erie...None.
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$$

AVIATION.....SC
DISCUSSION...MR
MARINE.......MR


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