Expert Forecast Opinion

115
FXUS63 KDTX 100905
AFDDTX

Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
505 AM EDT Tue Jun 10 2025

.KEY MESSAGES...

- A chance for a light shower with slightly below normal
temperatures.

- Much warmer weather is expected on Wednesday with highs well
into the 80s.

- A frontal boundary hanging around the area will lead to periodic
chance of showers and thunderstorms Wednesday night through
Saturday.

&&

.AVIATION...

Clear or mostly clear skies start the forecast period before remnant
strato-cu currently over northern WI invigorates diurnal cu
development across the region late morning into the afternoon.
Coverage varies between SCT to BKN through the afternoon-evening
with ceilings holding around 5kft. Despite increasing cloud cover,
diurnal mixing will support westerly wind gusts near or slightly
over 20kts throughout the bulk of the daylight hours. Winds then
weaken tonight with the loss of daytime heating in addition to
dissipating the lingering cu field.

For DTW/D21 Convection...No thunderstorms expected through the
period.

THRESHOLD PROBABILITIES...

* Medium in ceilings at or below 5000 feet late this morning
through early evening. Low by late evening.

&&

.PREV DISCUSSION...
Issued at 332 AM EDT Tue Jun 10 2025

DISCUSSION...

Large wavelength low pressure now centered over portions of Lake
Superior and the eastern U.P. will steadily fill today as the system
transitions into an open wave. Phasing of the upper level trough
with southern stream jet energy over the mid Atlantic will also
cause it to accelerate as it pushes into Quebec late this morning.
The wavelength is great enough to keep the heart of the midlevel
cold air, 775mb temperatures of approximately 2-3C, in place
throughout much of the daylight hours. Models have been consistent
in enough lower tropospheric moisture to allow for some modest
instability, 250 J/kg, centered at 5.0-6.0 kft agl this afternoon.
Some conflicting model signal on whether or not free convection will
be possible but the cumulus response should be fairly robust. The
chance for iso-scattered showers exist after 20Z and will maintain
the potential for a rumble of thunder in the Thumb. The main
narrative for today may be the breezy west winds of 15 to 25 mph.
This flow will aid deep mechanical mixing that should help
temperatures overachieve slightly into the low-mid 70s.

The exiting upper level trough will allow geopotential heights to
rise over Lower Michigan differentially. Increased thickness will
allow for a surge in temperatures Wednesday with the latest guidance
suggesting solid low to mid 80s. A notable increase in humidity is
also anticipated with surface dewpoints in the upper 50s to around
60 degrees. Despite the moisture forecast soundings support active
subsidence and associated capping/CIN in the 3.5 to 8.0 kft agl
layer. It remains difficult to envision a scenario with
precipitation Wednesday.

Models remain steadfast in suggesting that a strongly stable surface
anticyclone will build into portions of northwestern and northern
Ontario Thursday before slowing and putting on the brakes. In fact,
the models suggest it may take until Sunday for the center of the
surface high to push through Quebec. The positioning of this is
favorable for the development of easterly flow over the central
Great Lakes with a lake modification component allowing a quasi-
stationary baroclinic zone settling and sharpening over Lower
Michigan. Widely varying heat and humidity is anticipated across
this boundary. High uncertainty and low confidence exists in both
where activity will develop along this boundary and whether or not
any larger scale MCS systems will track along it. Alot of boom or
bust potential exists with this boundary. Still a long ways away to
provide much commentary and will refrain from any dry periods.

MARINE...

Outside of some elevated winds and gust around 20 to 25 knots
through the Saginaw Bay this morning with the favorable southwest
fetch, lighter winds will prevail for the remaining locations across
the Great Lakes as the pressure gradient eases in the wake of a cold
front. Outside of an isolated light pop up shower, dry conditions
prevail today. A warm front will then bring the chance for elevated
showers mainly for northern Lake Huron tomorrow and will again
produce some favorable southwest fetch for the Saginaw Bay which
bring additional chances to see winds aoa 20 knots. The frontal
boundary will then stall across the central Great Lakes which will
be the focal point for repeated shower and thunderstorm activity
through the midweek period.

&&

.DTX WATCHES/WARNINGS/ADVISORIES...
MI...None.
Lake Huron...Small Craft Advisory until 10 AM EDT this morning for LHZ421-422.

Lake St Clair...None.
Michigan waters of Lake Erie...None.
&&

$$

AVIATION.....KDK
DISCUSSION...CB
MARINE.......AM


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