240
FXUS63 KDTX 260347
AFDDTX

Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
1147 PM EDT Tue Jun 25 2024

.KEY MESSAGES...

- The greater chance for the next round of showers and possibly
  thunderstorms will be Wednesday with severe weather not expected
  at this time.

- Cooler and less humid air moves back into the area by Wednesday
  night and lasts through early Friday.

- Showers and thunderstorms return Friday night into Saturday.

&&

.AVIATION...

Some pockets of lower stratus will exist across the Detroit corridor
early this morning as low level moisture quality improvies, but with
observational evidence suggesting coverage remains at scatterd. A
brief broken coverage remains possible through this corridor,
featuring a lower VFR/marginal MVFR ceiling. This moisture may offer
a window for shallow fog formation during the early morning hours,
although confidence in occurrence remains quite low owing to
substantial high cloud and existing low level southwest gradient. A
moist and weakly unstable environment brings potential for shower
and thunderstorm development during the daylight period Wednesday.
Greater potential with southward extent, highlighted by a main
window from PTK southward for some convective showers and a lower
probability mention of tsra. Prevailing southwest winds lasting
throughout the day, shifting to northwest a frontal boundary sags
through the region late afternoon into the evening.

For DTW/D21 Convection...Low probability for thunderstorms will
exist from late morning into the afternoon on Wednesday.

DTW THRESHOLD PROBABILITIES...

* Low for ceilings aob 5kft overnight and Wednesday.

* Low for thunderstorms Wednesday.

&&

.PREV DISCUSSION...
Issued at 412 PM EDT Tue Jun 25 2024

DISCUSSION...

The early afternoon gusty winds associated with a wake low behind
the morning MCS should slowly begin to fall through the remainder of
the afternoon as conditions stabilize. Deep westerly flow will
continue to draw in slightly better lower level moisture, which will
support increasing daytime instability. However, the arrival of
warmer temperatures aloft are expected to keep a cap on any
additional development through the remainder of the afternoon. The
rain cooled airmass and clouds have tempered daytime highs down
slightly, especially across the south where clouds and back have
lingered into the early afternoon. Though we still have managed to
quickly climb into the lower 80s at some locations.

Some hi-res models want to trigger off some precip along a weak
prefrontal weak trough later this afternoon, mainly north of I-69.
The cap should still in place and should keep any potential activity
in check. Another round of showers and thunderstorms are then
expected to develop downstream with the increasing low level jet and
development of a surface low. The strongest activity is expected to
hold south of Michigan, but could see activity that develops and
moves along the southern border or possibly up to the I-94 corridor
of Lower Michigan during the evening. Confidence is not high with
this activity developing, especially up towards I-94. If it does, a
strong thunderstorm would be possible, but will be losing
instability with time into the tonight. By late morning/early
afternoon tomorrow, the influence of the northern stream shortwave
trough and cold front will increase lift across southeast Michigan
in tandem with inbound low from the southwest and bring greater
coverage of showers and thunderstorms. Meager mid level lapse rates
and weak forcing with the lack of stronger lower level jet winds
will preclude any severe mention at this time. However, MLCAPes of a
few hundred J/kg look possible with good deep layer shear will
support at least a general thunderstorm potential.

Once the cold front sweeps through on Wednesday high pressure
quickly builds across the region resulting in drier weather
conditions for Thursday into Friday. A cooler airmass marked by 850
mb temperatures down to around 6-8C will help temperatures cool down
more into the low/mid 70s outside of the urban heat island of
Detroit that may be more in the upper 70s. Greater moisture
advection returns on Friday as southwest flow increases ahead of the
inbound trough sweeping across the plains. Greater consensus among
models points towards Friday night into Saturday as the arrival time
for showers and thunderstorms ahead of a cold front. High pressure
and ridging aloft brings dry conditions to close out the weekend
into early next week.

MARINE...

Breezy conditions in the wake of the morning line of thunderstorms
gradually diminish over the course of the evening. There remains a
low chance ( ~20-30%) for a few showers or non-severe storms to
develop late this evening/tonight as a weak front sags through the
region- potential generally favored for waters south of Port Austin.
An upper level trough settles over the Great Lakes Wednesday as
upper Midwest surface high pressure begins to builds toward the
central lakes. Result is seasonably cooler, modest northerly flow
for Wednesday and Thursday with the only chances for storms confined
to the Ohio Valley, perhaps just clipping the far southern Great
Lakes. Otherwise, the surface high drifts over the region through
Friday before the next low arrives Friday night-Saturday.

&&

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

$$

AVIATION.....MR
DISCUSSION...AA
MARINE.......KDK

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