Expert Forecast Opinion

750
FXUS63 KDTX 252232
AFDDTX

Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
632 PM EDT Tue Mar 25 2025

.KEY MESSAGES...

* Some light lake-effect snow showers or flurries are possible for
the Tri-Cites and Thumb areas this evening into early tonight.

* Chilly start to Wednesday morning with wind chills near 20F.

* Gradual moderation in temperatures through the rest of the week
with 50s returning by Thursday and 60s by Friday-Saturday. Rain
chances also return by Friday through this weekend.

&&

.AVIATION...

The loss in diurnal mixing will result in some decrease in the cloud
coverage across the Detroit terminals this evening. A short wave
trough will however sustain some degree of clouds across the north
well into the evening hours. There is also some indication in the
latest model suite that some additional moisture now resulting in
the strato cu field across NE Wisconsin will track across Se Mi
during the overnight. These factors will result in varying degrees
of cloud coverage through the night. Per upstream observations and
considering the degree of low level dry air, cloud bases will remain
in the 3500 to 6000 foot range. Large scale subsidence and weak sfc
high pressure will support clear skies by 10 to 13Z Wed morning. The
loss in diurnal mixing this evening will support some drop in sfc
wind speeds/gusts. A shallow mixed layer is shown in model soundings
which may hold sfc winds around or just above 10 knots for several
hours past sunset.

.DTW THRESHOLD PROBABILITIES...

* Medium for ceilings at or below 5000 feet tonight.

&&

.PREV DISCUSSION...
Issued at 252 PM EDT Tue Mar 25 2025

DISCUSSION...

Embedded shortwave trough dropping over northern lower MI will
support lingering scattered lake effect light snow showers/flurries
through the evening for the Tri-Cities/Thumb. With additional
moisture flux of the Saginaw Bay, Huron county stands the best shot
at seeing accumulations, though only up to a couple tenths of an
inch at most. Snow tapers off overnight as the shortwave peels away
into eastern Ontario though with backedge winds turning more
northerly, a few light snow showers could clip the eastern Thumb
early Wednesday morning. Surface high pressure then expands over the
central Great Lakes for Wednesday and Thursday keeping precip
chances to the north and south of our area and leading to a
moderation trend in temps to close out the work week.

Active pattern redevelops by Friday as a warm front is lifts through
the state bringing numerous showers as well as ushering in much
warmer air with 850mb temps climbing to around 10C. Deterministic
and ensemble average trends have continued to favor this front
stalling between northern lower and the Straits keeping the axis
heavy rainfall (2+ inches) just north of our CWA. With this still 3
days out, some deviation in the expected location of the stationary
frontal boundary is possible and warrants monitoring. Periods of
moderate to heavy rainfall are still possible this weekend even in
this northern stationary front scenario as a southern stream
shortwave phases with this northern stream trough reaching the
southern Great Lakes/Ohio Valley daytime Sunday. Exactly how far
north this wave tracks is still unclear with some solutions like the
12Z GFS keeping it over central Ohio vs other solutions like the
00/12Z ECMWF draw it into northern Ohio/southeastern Michigan.
Several hundred J/kg of MUCAPE accompany the northern flank of this
wave so a more northerly outcome like the ECWMF would also support
scattered thunderstorms latter part of the day Sunday. A few could
be strong to severe as bulk shear resides around 35-40kts.

Surface low is progged to eventually track over lower MI late Sunday-
Monday generating additional widespread rainfall with a backside
transition to rain-snow or all snow before vacating Monday evening.
Upper troughing holds over the Great Lakes following this wave
favoring a return to cooler, below normal temperatures to start out
next week.

MARINE...

A cold front drops across Lake Huron tonight bringing a brief
increase in north to northwest wind to around 20 to 25 knots as well
as additional snow showers. High pressure builds directly into the
central Great Lakes on Wednesday leading to decreasing winds through
the day. Flow then reorients out of the southwest on Thursday in
advance of the next cold front moving into Lake Superior. This looks
to peak in the 20 to 25 knot range, but there will be a 40% chance
for a brief period of 30 to 35 knot gusts across northern Lake Huron
on Thursday afternoon as the front moves in and shifts wind to the
west/northwest. At this time confidence remains too low on
occurrence and duration, so will hold off on a Gale Watch. A warm
front stalls across the region Friday into Saturday bringing
widespread precipitation and increasing likelihood for stronger
easterly winds.

&&

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

$$

AVIATION.....SC
DISCUSSION...KDK
MARINE.......TF


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