Harrison Township, Michigan Weather Forecast Discussion

543
FXUS63 KDTX 232241
AFDDTX
Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
641 PM EDT Tue Sep 23 2025
.KEY MESSAGES...
- Potential exists for scattered to numerous showers and
thunderstorms to develop throughout the mid week period. Localized
heavy rainfall may be possible.
- Temperatures in the 70s through the remainder of the week, which
will generally be at to slightly above normal.
&&
.AVIATION...
The cluster of showers/thunderstorms extending southwest of KMBS to
the KGRR area has a definite diurnal component and will likely
decrease with the loss of daytime heating this evening. The area of
light rain extending across the KAZO and KBTL areas may attempt to
rotate into the metro Detroit terminals this evening, although
current trends are weakening. The presence of the upper low over the
Great Lakes and weak instability through the night may allow some
lingering showers into the night, the chances of which are low
enough as to not include the mention in the TAFs. VFR conditions
this evening are expected to give way to low clouds and fog
overnight given ample low level moisture and light winds. IFR and
LIFR conditions are highly probable. There is a dense fog potential,
which will rely to some degree on the extent of mid/high clouds
during the overnight. Low clouds and fog will linger well into the
morning as rain chances increase.
For DTW/D21 Convection...The better convective chances this evening
will generally be south of KTOL. There is only a slight chance for
additional thunderstorm development tonight.
DTW THRESHOLD PROBABILITIES...
* High in ceilings aob 5000 feet overnight and Wednesday.
* Medium for cigs/vsby to 200ft and/or 1/2sm late tonight/early
  Wednesday morning.
* Low for thunderstorms tonight and Wednesday.
&&
.PREV DISCUSSION...
Issued at 401 PM EDT Tue Sep 23 2025
DISCUSSION...
Ambient conditions remain marked by high quality low level moisture
late this afternoon, as the resident environment changes little
within the grip of mid level troughing south of a closed low still
stationed near the Straits. Poorly resolved corridor of convection
featured along mid level impulse and associated upper level jet core
chugging eastward at press time. Strongest cores with this activity
have proven worthy of small hail, with a risk for wind gusts to 50
mph and locally heavy downpours going forward this afternoon. Within
the immediate wake of ths activity, additional dcva  n pace to
streak across the area late this evening. This will offer another
opportunity for organized forced ascent to emerge across a portion
of the forecast area. Given a weakly unstable underlying profile,
expectation remains for some additional shower and thunderstorm
development. Given the moisture quality and depth and somewhat
limited deep layer shear, any better convective cores will again
carry potential for some efficient rainfall rates. Environment will
remain supportive of additional pockets of convection into the
overnight period, particularly across the south as a weak frontal
boundary sags into the region. Conducive near surface conditions
once again will support a high coverage of low stratus and/or fog
late tonight.
Attention Wednesday and Wed night focued on behavior of a mid level
wave and associated surface low set to eject northeast across the
Ohio valley. Some model differences remain in handling the
interaction or consolidation of height falls as this wave engages
the cyclonic periphery of the great lakes low. This brings
corresponding latitudinal variability in trajectory, leaving
southeast Michigan positioned tenously close to the pronounced axis
of deformation forcing and greater rainfall potential held on the
north/northwest flank of this system. There remains a smaller subset
of the solution space that allows for a more northerly trajectory,
which brings a higher probability to witness a focused axis of qpf
in excess of 1 inch. Lower confidence on this outcome, with a
majority of the guidance simply offering a high probability for
scattered to numerous showers and thunderstorms to develop at times,
as the mid level frontal boundary pivots into the region and engages
continued very moist and weakly unstable conditions. This still
maintains the possibility for locally heavy rainfall with dependence
on storm motion as cells track to the north and west.
Upper low finally releases eastward Thursday, the passage of the mid
level trough extension offering one final round of showers and
thunderstorms during the daylight period. Dry conditions return
Friday under shortwave upper ridging, with a brief period of warm
air advection affording above average temperatures. Thermal ridge
entrenched Saturday ensuring the warmest conditions this forecast
period. Milder weather persists into the latter half of the weekend,
with dry conditions expected.
MARINE...
Upper level trough continues to reside over the Great Lakes region
while a frontal boundary slowly sags down through the area. A
surface low will track up along the front tonight through Wednesday
which will keep chances of showers and thunderstorms in the forecast
through Thursday. Wind field continues to be weak with little wind
being generated from any of the current storms, but could see an
isolated gust to 35 knots from stronger storms. Winds will become
northeasterly today behind the front and remain northeasterly
through midweek. High pressure then builds in for the end of the
week bringing quieter weather to the region again.
HYDROLOGY...
Very moist and weakly unstable conditions will maintain potential
for scattered to numerous showers and thunderstorms throughout the
midweek period. A storm system lifting northeast across the Ohio
valley may also result in a more widespread, significant rainfall
lifting north into the region Wednesday into Wednesday night.
However, confidence in this occurrence remains low at this time.
Forecast currently calls for a larger spread in basin average
rainfall totals through Thursday given the variability in coverage,
with generally one half to one inch expected. Localized higher
amounts ranging of up to 2 inches will be possible where repeated
activity occurs or should the storm track shift north and bring a
more focused region of rainfall. Localized flooding of urban, low-
lying and poor drainage areas along with rises in area rivers will
be possible.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...None.
Lake Huron...None.
Lake St Clair...None.
Michigan waters of Lake Erie...None.
&&
$$
AVIATION.....SC
DISCUSSION...MR
MARINE.......DRK
HYDROLOGY....MR
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NWS DTX Office Area Forecast Discussion