253
FXUS63 KDTX 300342
AFDDTX

Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
1142 PM EDT Mon Apr 29 2024

.KEY MESSAGES...

- Potential exists for showers and thunderstorms to develop through
  the evening. There is a marginal risk for storms to become severe
  during this time. Damaging wind gusts will be the main threat,
  although a brief tornado cannot be ruled out across the thumb.

- Dry and slightly cooler Tuesday.

- Well above normal temperatures remain through the week.

&&

.AVIATION...

The back edge of the light showers will be east of metro Detroit
around TAF issuance. Some thinning of the mid/high cloud deck
overhead may open the door to some low clouds and/or fog development.
This will be most probable at the metro Detroit TAFs where evening
rainfall has contributed to increased boundary layer moisture. A
weak cold front will then move across Se Mi in the 06Z to 09Z time
frame. A gradual wind shift to the west will occur with the passage
of this front. Subtle post frontal dry air advection should erode
any low clouds/fog toward daybreak. DIurnal heating and some remnant
low level moisture will contribute to a scattered to broken diurnal
cu field Tues afternoon.

For DTW/D21 Convection...The risk of lingering convection has ended
across the airspace. No thunderstorms are expected through the TAF
period.

DTW THRESHOLD PROBABILITIES...

* Moderate in ceilings aob 5000 feet tonight. Low on Tuesday.

&&

.PREV DISCUSSION...
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.

&&

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

$$

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


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