337
FXUS63 KDTX 012303
AFDDTX

Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
703 PM EDT Wed May 1 2024

.KEY MESSAGES...

- Above normal temperatures continue through the rest of the week
  and into the weekend.

- Showers and thunderstorms (70-80% chance) return on Friday.

&&

.AVIATION...

Clear sky across SE Mi is the result of slightly cooler but much
drier air trailing the cold front that is now east of the region.
Westerly wind gusting in the 25-35 kt range during the afternoon
quickly decouples with sunset and settles into a light NW direction
as weak high pressure builds in from the upper Midwest. The high also
supports VFR under clear sky with a few patches of cirrus tonight
and much of Thursday. It`s not until late in the day when a more
notable increase in mid and high clouds occurs accompanied by light
wind becoming a lake breeze enhanced SE direction into Thursday
evening.

For DTW/D21 Convection...Thunderstorms are not expected through the
TAF period.

DTW THRESHOLD PROBABILITIES...

* None.

&&

.PREV DISCUSSION...
Issued at 318 PM EDT Wed May 1 2024

DISCUSSION...

The ongoing passage of a cold front, which coincides with peak
diurnal heating, have allowed daytime highs to push into the mid to
upper 70s. The capped and dry environment along the front will
inhibit showers production and at best has been met with cumulus
congestus along and ahead of the front. Deep mid to upper level
subsidence in the wake of the front coupled with mixing will prevent
cloud cover from redeveloping. This brings sunny skies for the
remainder of the afternoon and evening. Ongoing breezy conditions
with gusts 25 to 35 mph will cease after sunset as the stable layer
settles in. For tonight, very subtle cold air advection coupled with
generally clear skies (outside of periodic cirrus), will drop
temperatures into the 40s for a low.

Diffuse surface high pressure alongside shortwave ridging aloft will
bring another round of dry conditions tomorrow. The possible
exception will be the shallow corridor of weak system relative
isentropic ascent centered around h800 that will bring the low-end
chance to see sprinkles or a stray shower through the afternoon and
evening, but confidence is too low for measurable precipitation to
constitute any PoP values above 15%. Otherwise, temperature highs
return into the 70s, outside of the Tri-Cities and bordering
shoreline, as northeast flow ushers cooler air inland. A stark
difference along the shoreline will be felt with highs in the mid
50s.

An upper-level wave stemming from a meandering upper-low across the
Central Plains will pinch off into the upper Great lakes Friday,
which will amplifying the aforementioned ridge downstream across the
southern Great Lakes. This will usher in temperatures that will
rival today, characterized by h850 temperatures up to 15C by Friday
morning. With the warmer air will come the amplified Gulf stream
moisture, pushing PW values aoa 1.20 inches. A shortwave trough will
capitalize on the enhanced moisture and will likely bring periods of
rain showers with embedded thunderstorms, with the best chances
centered Friday afternoon and evening. Thunderstorm potential and
characteristics of thunderstorms are still under question as this
period falls outside the hi-res window (outside of 3km NAM). The
GFS/3KM NAM showcase low-level capping and inhibit CAPE potential,
while the NAM affords a period of free convection with a marginal
wind threat. Modeled analogs do not highlight strong or severe storm
potential which is the ongoing message at this time.

Additional shower and thunderstorm chances exist both Saturday and
Sunday under the warm airmass with shallow moisture, but again
capping with resident dry air in the mid-level uncertainty is high
regarding upscale growth potential. The potential for unsettled
weather will continue into next week with long-range models
projecting the development of low pressure across the northern Plains
to western portions of the midwest, which will reinforce warm and
unstable conditions across the Great Lakes.

MARINE...

Gusty southwest to westerly flow within the immediate wake of cold
frontal passage will persist through the evening hours, before
gradually diminishing with loss of daytime heating. This will
maintain small craft conditions from Saginaw Bay to the lake Huron
nearshore waters along the tip of the thumb. Modest wind speed from
the northwest expected overnight and early Thursday as high pressure
builds into the region. Winds establish an easterly component late
Thursday as the high exits the region. A low pressure system is
forecast to track across the northern great lakes Friday. This will
draw a cold front through lower Michigan, bringing increasing
potential for showers and thunderstorms particularly during the
afternoon and evening hours. Winds holding from the southeast at
less than 20 knots in advance of this front Friday.

&&

.DTX WATCHES/WARNINGS/ADVISORIES...

MI...None.

Lake Huron...Small Craft Advisory until 9 PM EDT this evening for LHZ421-422-441.

Lake St Clair...None.

Michigan waters of Lake Erie...None.

&&

$$

AVIATION.....BT
DISCUSSION...AM
MARINE.......MR


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