457
FXUS63 KDTX 022356
AFDDTX

Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
756 PM EDT Sun Jun 2 2024

.KEY MESSAGES...

- Temperatures warm up Monday and Tuesday with highs returning to
the 80s. Chance for showers or storms Tuesday.

- Showers and some thunderstorms likely Wednesday as a major weather
pattern shift begins. After Wednesday, below normal temperatures are
likely through at least the end of the week.

&&

.AVIATION...

Increasing subsidence will continue to scour out lower clouds
heading into tonight bringing a period of VFR skies. Good
radiational cooling will set up with dewpoints in the 50s along with
light winds and clear skies. This bring a relatively high
probability for widespread fog to develop within the light northerly
flow across all TAF sites shortly after 06Z tonight. Expecting
IFR/LIFR restrictions into sunrise with the typical post sunrise
dissipation to VFR towards the late morning. VFR skies will carry
through the late morning and early afternoon with some lingering
scattered cumulus around 4kft.

For DTW/D21 Convection...Thunderstorms are not expected through this
forecast period.

DTW THRESHOLD PROBABILITIES...

* Low for ceiling at or below 5,000 feet from 02Z to 06Z this
  evening.

* Moderate for cigs/vsby falling below 200 ft and/or 1/2 SM
  after 06Z tonight and to around sunrise tomorrow morning.

&&

.PREV DISCUSSION...
Issued at 300 PM EDT Sun Jun 2 2024

DISCUSSION...

A shallow but saturated boundary layer will continue to promote
extensive stratus to strato-cu through the afternoon, where surface
based cape values now reside between 250-500 J/kg, outside of the Tri-
Cities down into Flint. This diurnally fueled instability in
conjunction with multiple weak surface convergence boundaries will
support pockets of drizzle to spotty showers activity through the
evening. This will not be a supportive environment for thunderstorm
development as soundings and water vapor imagery showcase copious
amounts of dry air aloft along with an inversion above the start of
the dry layer. The weak updrafts and shallow cloud tops will reside
well below the freezing level, preventing ice nucleation.

Any lingering showers will quickly wane this evening into late
tonight with the loss of daytime heating coupled with dry air
advection which will scour out low-based cloud cover. Taking into
account the widespread light rainfall that fell last evening into
this morning and the extensive cloud cover which hampered the drying
out of soil moisture, overnight clearing trends will set the stage
for fog potential. Calm to light surface winds and condensation
pressure deficits dropping to 2mb or less within the hi-res suite
will support patchy to areas of fog, dense at times. Visibility
restrictions from fog will improve by the late morning hours once
daytime heating lift and scours out the surface condensation.

SE MI will then reside just east of the Gulf moisture conveyer belt
which extends from Texas up through western Lake Superior. A series
of shortwaves along this belt, some convectively enhanced, will
reinforce shortwave ridging across SE MI tomorrow. The return of
sunshine, outside of translucent cirrus, and warm air advection will
push highs back into the 80s. Upper-level ridging will sustain into
Tuesday once a potent upper-level wave arrives onshore across the
Pacific NW tomorrow, before pushing into the upper plains. This will
advect in h850 temperatures around 17C and will bring the warmest
temperatures of the week with highs in the mid to upper 80s. The
constant flux of warm air advection will also make for warm
overnight lows leading into Wednesday, with temperatures only
dropping into the upper 60s. There will be a couple chances for
showers and storms on Tuesday, the first being the low chance for
decaying activity upstream to make it into the Tri-Cities/Thumb
Tuesday morning. Chances then creep upwards once the Gulf moisture
starts to expand into the eastern portion of the state.

A major pattern shift will then commence Wednesday, lasting through
the end of the weekend and possibly into early next week. The
aforementioned Pacific wave will arrive across the Midwest and will
possibly get pinched off into a closed upper level low over the
Great Lakes Thursday into the end of the week. This pattern has the
potential to turn into a blocking pattern with two dipoles of high
pressure forming along the flanks of the low, across the central
Canadian Provinces and out over Greenland. This will initially
result in the Gulf moisture setting up right over SE MI on
Wednesday, bringing the likely chance for showers and storms. The
meandering influence of the low coupled with an elongated jet stream
that develops and holds over the Ohio Valley will then lock in below
normal temperatures Thursday into at least the weekend, and will
bring the chance for showers and storms every day. This energetic
pattern will also maintain stronger winds aloft, bringing breezy
conditions (30 mph) during daylight hours Wed-Thu-Fri. Overall this
is a high confidence setup, outside of the nuanced details
pertaining to the extent of the geopotential height anomaly strength
and the staying power of this trough next week. More of the variance
surrounds the strength of the trough and extent of cooler air over
the Great Lakes, which will impact how far temperatures can drop
below the normal averages. At this time highs range between the upper
60s to mid 70s.

MARINE...

Low pressure is currently making its way out of the region, with
light showers lingering through the evening. Upper level shortwave
ridge brings a brief period of high pressure tonight into Monday.
Light northeasterly winds will support the development of patchy fog
over the lake early Monday morning, but after sunrise the fog will
dissipate. Approaching warm front brings chances for showers and/or
storms to develop on Tuesday. Winds remain moderate ahead of the
front, but level flow up to 25 knots is expected about 1000 feet
above the surface meaning a stray strong gust mixing to the ground is
possible. The warm front will then be followed by a strong cold
front on Wednesday, sustaining the chances for thunderstorms.

&&

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

$$

AVIATION.....AA
DISCUSSION...AM
MARINE.......BC


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at www.weather.gov/detroit.