Pontiac, Michigan 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

547
FXUS63 KDTX 170713
AFDDTX

Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
313 AM EDT Thu Apr 17 2025

.KEY MESSAGES...

- Showers and possible thunderstorms developing late tonight,
particularly north of I-69.

- Warm and windy on Friday with high temperatures well into the 70s
to near 80 degrees. Southerly wind gusts of 30-40 mph expected in
the afternoon.

- There is a slight risk of severe thunderstorms Friday evening into
early Friday night.

&&

.DISCUSSION...

A cold and frosty morning to start the day, as temperatures rise out
of the mid 20s to lower 30s.

Water vapor imagery shows a potent upper level wave dropping south
through the Pacific Northwest, which will drop into the Four Corners
region by Friday evening. This feature will help direct subtropical
moisture/energy into the western Great Lakes by Friday morning.
Thus, still looking at an active warm front, but the 850-700 MB jet
core (60+ knots) is forecasted to track through northern Lower
Michigan (6-10z), thus confidence in showers and even possible
thunderstorms (as negative showalter indices arrive) does drop off
as one heads southeast. With that said, still think majority of
southeast Michigan will see showers Thursday night after looking at
various hi-res solutions, and knowing the models typically struggle
with the elevated high based activity/warm advection wing. Locations
north of M-46 overwhelmingly stand the best chance to exceed rainfall
of a quarter of an inch through 15z Friday. 00z HRRR is even developing
an aggressive MCV moving through, which would bring a small hail
threat with very steep mid level lapse rates. Tough to latch onto
this solution fully just yet.

Surface warm front should make it to Saginaw Bay during the day,
placing the bulk of southeast Michigan in the warm sector. The
question is how clean will the warm sector be, as the NAM is
exceptional moist in the low levels, keeping low clouds in locked
in, with even some drizzle/very light rain possible. Preference is
with a drier, warmer, and subsequently windier solution with the
increased mixed depths, as suggested by regional gem. Our local
probabilistic guidance suggests wind gusts of 35-40 MPH as
temperatures have potential to reach 80 degrees with 850 MB temps
reaching at or above 13 C. Extreme capping, mid level warmth and dry
air indicated after the early morning activity exits, thus not
expecting any thunderstorm activity in the afternoon, as MUcapes
reach 750-1500 J/kg. Cooling mid levels and large scale ascent
attempts to spread in during the evening, but low levels will be
stabilizing, with capes cut in half by midnight. SPC Day 2 outlook
continues to advertise a slight risk of severe thunderstorms. The
steep mid level lapse rates and wind shear certainly needs to be
respected, and our severe chances (hail/wind/very low risk of
tornado) hinge on the timing of the activity/cold front moving in
earlier in the evening. However, preference is toward the muted
solutions such as the 00Z Euro/NAM, suggesting the front will be
arriving just a bit too late to support much in the way of severe
thunderstorms, as the cap is just too strong and takes too long to be
eroded.

The front is actually losing its forward speed Friday night, and the
boundary may hang around the southern Michigan border Saturday
morning, as an upper level shortwave tracks northeast through the
Ohio Valley. If this shortwave is stronger and a surface reflection
develops, could see rain showers impact southern areas on Saturday
(see Canadian solution), but confidence is not high in this scenario
as high pressure builds east through the northern Great Lakes. This
high will give way to another strong low pressure system tracking
through the western Great Lakes Sunday night, bringing another round
of showers and possible thunderstorms to end the weekend into
Monday. Once again, the bulk of the activity and heavy rain looks to
reside northwest of the CWA.

&&

.MARINE...

Quiet marine conditions expected today under light southeast flow.
Gradient wind increases throughout the day as low pressure organizes
over the Plains. Elevated portions of the warm front move toward the
Great Lakes early Friday morning, triggering elevated showers and
thunderstorms along with an uptick in winds and wave action that may
require Small Craft Advisories. Once morning convection subsides,
warm conditions develop across the Great Lakes ahead of the system
cold front which will slowly track across the area late Friday night-
Saturday morning. This front will be the focus for additional
thunderstorm activity, in which some storms could become strong to
severe depending on how unstable the atmosphere gets. The front
slowly settles into the Ohio Valley, but may trigger additional
rounds of precipitation through the weekend.

&&

.PREV DISCUSSION...
Issued at 1203 AM EDT Thu Apr 17 2025

AVIATION...

VFR conditions will prevail through the TAF period with southeast
Michigan currently under the influence high pressure and dry air.
Light and variable winds expected through the early morning hours
under clear skies. High clouds increase throughout the day tomorrow
ahead of the next low pressure system as winds become southerly.
There will be an increasing chance for rain showers near the end or
shortly after the end of this TAF period. Highest chances focused
toward FNT and MBS.

DTW THRESHOLD PROBABILITIES...

* None


&&

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

$$

DISCUSSION...SF
MARINE.......MV
AVIATION.....AA


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