Howell, Michigan Weather Forecast Discussion

611
FXUS63 KDTX 250647
AFDDTX
Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
247 AM EDT Thu Sep 25 2025
.KEY MESSAGES...
- Chance (20-40%) for isolated to scattered showers for all of SE MI
today.
- Slight chance (20%) for an isolated to scattered showers across
  the Tri-Cities and Thumb tomorrow evening.
- Extended period of dry weather and sunshine this weekend into at
least early next week.
&&
.DISCUSSION...
A closed low system over the Great Lakes will depart open up and
depart eastward through the afternoon and evening hours. The weaker
surface low over Lake Erie will maintain cyclonic flow across SE MI
through the day. This pattern supports isolated to widely scattered
showers favored in the late afternoon the evening hours as low-level
lapse rates steepen with diurnal heating. Weak capping through 10-
12kft will limit convective potential, precluding any organized or
robust convective development. Likewise, this setup favors the
ongoing maintenance of an extensive low stratus deck through the
first half of the day until better boundary layer mixing can work to
erode some cloud cover. Increasing subsidence and loss of daytime
heating will continue to degrade cloud cover tonight into early
tomorrow morning. Any extended period of clear skies will bring
potential for fog development, but confidence is low regarding
materializing and extent at this time. Have included patchy fog
wording in the forecast package.
A pattern shift will then commence tomorrow that will bring an
extended period of mostly dry weather and some extended periods of
sunshine that will hold through at least the midweek period. A
pseudo omega block pattern will amplify ridging across the Plains
this weekend. One of the lows near the four corners region will
weaken through early next week but longwave amplification of the
trough across the Pacific in conjunction with tropical activity over
the western Atlantic will strengthen this ridge well into the
Canadian Provinces and eventually into the Midwest/Great Lakes
region. EPS guidance shows a 95-100 percent probability of heights
reaching or exceeding the 90th percentile showcasing the very strong
convergence within ensemble guidance. Prior to the enhanced ridging,
the one day that will be susceptible to some rain showers outside of
today will be tomorrow evening into early Saturday morning focused
across the Tri-Cities and Thumb, along an elevated frontal boundary.
Temperature highs gradually increase day-to-day with highs in the low
80s expected by the weekend. Overnight lows hold in the low to mid
50s.
&&
.MARINE...
Upper low that has lingered over the region this week begins to
gradually shift east over the course of today. Shower and embedded
thunderstorm coverage are spottier today relative to prior days with
drier conditions developing by late evening as the low fully peels
away. Winds generally remain on the lighter side, aob 15kts, out of
the north today before further weakening overnight as weak high
pressure begins to expand into the Great Lakes. A weak cold front on
the preceding the edge of the high offers a low chance to see a few
spotty showers Friday morning-afternoon, otherwise quiet marine
weather takes holds for the weekend.
&&
.PREV DISCUSSION...
Issued at 1132 PM EDT Wed Sep 24 2025
AVIATION...
Departure of mid/high clouds appear to be opening the door to
stratus development per recent observations. Low level moisture
trapped under a developing shallow inversion will continue to allow
expansion of low end MVFR and IFR based clouds during the pre dawn
hours. With sfc dewpoints still holding in the low 60s, some stratus
build down processes may lead to areas of fog, possibly dense.
There continues to be indication in both NAM and RAP soundings that
the development of a light northerly wind field in the boundary
layer toward 12Z Thurs will support some improvement in conditions
to VFR. Some additional improvement will persist into early
afternoon. The passage of an upper level wave will support a chance
of showers, isolated thunderstorms Thurs afternoon. Convective
coverage will be limited by weak instability and dry air in the mid
levels.
For DTW/D21 Convection...Any convection across the airspace Thurs
afternoon will be isolated.
DTW THRESHOLD PROBABILITIES...
* High in ceilings aob 5000 feet tonight and Thursday.
* Low for cigs/vsby to fall below 200 ft and/or 1/2SM Thursday morning.
* Low in thunderstorms Thursday afternoon.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...None.
Lake Huron...None.
Lake St Clair...None.
Michigan waters of Lake Erie...None.
&&
$$
DISCUSSION...AM
MARINE.......KDK
AVIATION.....SC
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at www.weather.gov/detroit.

NWS DTX Office Area Forecast Discussion