038
FXUS63 KDTX 130741
AFDDTX

Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
341 AM EDT Fri Jun 13 2025

.KEY MESSAGES...

- Increasing chances for rain showers this evening and overnight,
mainly for I-94 south.

- Warming trend heading into the weekend with a return back to the
80s through early next week.

&&

.DISCUSSION...

The stationary frontal boundary over the northern Ohio River Valley
will pivot north in southern Michigan later this morning through the
early afternoon in response to the east-northeast progression of the
mid-level wave presently now over Missouri. This boundary will again
stall out in response to dry ENE flow from a Canadian high pressure
system which will oppose moisture advection ahead of the upstream
wave. This setup will establish a sharp moisture gradient over
southeast Michigan, through no physical impacts (e.g. appreciable
rain) are expected through the first half of the day outside of a low
chance for isolated to widely scattered showers given subtle
elevated forcing in place.

Shower chances increase considerably this evening into the overnight
hours along and south of I-94 as the aforementioned wave extends
through the Ohio Valley. In response, appreciable forcing will
likely be observed through the mid-levels with system-relative
isentropic analysis highlighting elevated moist ascent through 850
to 400mb. Otherwise, will preclude thunder mentions given poor mid-
level lapse rates and lack of instability. The one caveat noted in
the latest 00Z guidance -- While the HREF LPMM QPF retains any higher
end rainfall totals holding south of the state line, EPS outlier
solutions highlights ~15-20 percent of the solution space producing
rainfall totals in excess of an inch around and south of I-94, which
is a solution also being reflected in the latest 06Z HRRR. This would
be owing to strong midlevel forcing in which case, the thermodynamic
forcing alone would be enough to produce thunderstorms along with
some extended periods of locally heaver rainfall. This trend will
continue to be monitored through the day. Otherwise, it remains
possible for some light showers to make it north of I-94 through
about M59, however, PoP values ramp up considerably closer to the
MI/OH border, aligning with the deeper moisture and more favorable
ascent.

Lingering rain chances will be possible through late tomorrow
morning until high pressure drops south into the Great Lakes,
dissolving mid-level convergence. Influence of high pressure will
promote dry conditions through Monday, before the combination of
increased moisture transport from return flow of the departing high
in conjunction with a more active pattern brings increasing chances
for rain and thunderstorms through the middle of next week.
Temperatures are expected to get progressively warmer leading into
early next week, peaking in the mid and possibly upper 80s by Monday-
Tuesday, pending any rain and thunderstorm chances.

&&

.MARINE...

A low pressure system over Missouri and the associated frontal
boundary will continue to influence conditions over the Great Lakes
region into the start of the weekend.  This will maintain
northeasterly flow with lighter winds over the region. Northeast
winds on Friday will increase into the 15 to 20 kt range across Lake
Huron, with 25 kt gusts possible across the Saginaw Bay.  Showers
and embedded thunderstorms will spread across the region Friday into
Saturday, with severe weather not anticipated at this time.  High
pressure then builds back in on Sunday, which will bring drier
conditions and light winds.

&&

.PREV DISCUSSION...
Issued at 1140 PM EDT Thu Jun 12 2025

AVIATION...

Southeast Michigan will remain located between an elevated frontal
boundary across the northern Great Lakes and a broad low pressure
system and moisture plume from Missouri across the Ohio Valley
through the day Friday. This will essentially sustain limited large
scale forcing across the southeast terminals. The northern edge of
an elevated instability axis lifted across SW Lower Mi late this
evening, igniting a line of convection. The elevated instability is
forecast to weaken during the overnight, limiting the chances for any
convection at the Se Mi terminals. Light east-northeast winds
associated with high pressure centered north of Lake Huron will
maintain enough dry air in the low levels to sustain VFR conditions
through Friday afternoon.

For DTW/D21 Convection...An isolated thunderstorm remains possible
late tonight through Friday morning, mainly across the western
portions of the airspace.

THRESHOLD PROBABILITIES...

* Low for thunderstorms tonight and Friday.


&&

.DTX WATCHES/WARNINGS/ADVISORIES...
MI...None.
Lake Huron...Small Craft Advisory from 2 PM this afternoon to 4 AM EDT Saturday
     for LHZ421-422.

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

$$

DISCUSSION...AM
MARINE.......SS
AVIATION.....SC


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