Southeast, Michigan Weather Forecast Discussion

823
FXUS63 KDTX 252003
AFDDTX
Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
403 PM EDT Thu Sep 25 2025
.KEY MESSAGES...
- Isolated showers move through this evening with a rumble of thunder
  or two still possible.
- Mainly dry tonight and most of the weekend, although areas north of
  I-69 could see a few showers Friday evening.
- Warmer temperatures are expected into early next week with highs
  breaking 80F at times.
&&
.DISCUSSION...
Primary mid-level circulation noted in afternoon GOES vapor imagery
continues to dislodge across southern Lower Michigan today. The
passage aloft provides a tendency for ascent prior to 02Z,
triggering isolated shower activity. Latest forecast soundings lack
deep-layer saturation, and mid-level lapse rates are mediocre (around
6 C/km). As a result (and per latest radar trends), not expecting
any broadening of convective coverage through the rest of the day
with generally low cloud tops. Still cannot completely rule out a
rumble or two of thunder given skinny MLCAPE profiles up to 350 J/kg
and equilibrium levels above 20 kft AGL. Pervasive subsidence layer
in the 5-10 kft AGL layer atop weak capping inversion has thus far
won out in suppressing more robust updrafts. Still, narrow diameter
storm-scale circulations will percolate from west to east the rest of
the evening with minimal impact, aside from some brief rainfall. Did
cut PoPs to low-end Chance (25 percent). Dry conditions fill in
between 00Z and 02Z as mid-upper level winds flip 180 degrees, from
southwesterly to northeasterly for the rest of the overnight hours
and into Friday.
The upper low exits into the eastern Great Lakes Friday morning,
guided by a southern stream speed max ejecting northeastward into an
amplified longwave trough over eastern Canada. This draws in local
geopotential height rises downstream of western CONUS ridging
throughout the first half of the day. Expect a dry start with
increasing subsidence through most of the column and decreasing
cloud fraction through the diurnal cycle. Main point of
consideration will be the potential for light showers to develop
along an approach cold front. Latest deterministic models suggest
this boundary extends beyond Mid-Michigan and could spill into
communities north of M-46 (perhaps even closer to I-69).
Perturbation in the mid-level flow is expected to elicit a weak
surface low along the front by 18Z. Made some revisions to PoPs such
that Slight Chance wording will be featured for the 18-00Z time
range before the front becomes stationary. Several degrees warmer
Friday with highs in the mid to upper 70s.
The front gets hung up somewhere over the northern portion of the
CWA Friday night into Saturday morning with low confidence in any
additional precipitation. The boundary then retreats as a warm front
with time Saturday as warm advection moves in amidst strengthening
southwesterly LLJ. This arrives with a progressive Pacific shortwave
trough moving east along the US/Canada border. The stronger flow
field better aligns with the UP and northern Lower, therefore dry
weather is expected downstate into Sunday. The warm sector will
still be in-place Sunday with 850 mb temperatures of 14-15C, thus
highs in the low 80s are favored. The 590 dam 500 mb ridge centers
over the Mid-Mississippi Valley Sunday, and lingers across The
Midwest Monday and Tuesday. This limits rain chances while
preserving above normal temperatures. Additionally, this anticyclone
should help shield the Great Lakes from any Mid-Atlantic tropical
system(s) that the latest model runs have shown could make landfall
and persist over portions of eastern CONUS.
&&
.MARINE...
Upper low fully vacates the region by early tonight as weak high
pressure from the northern Plains begins to expand into the Great
Lakes. Aside from a few spotty showers Friday along a weak cold
front marking the lead edge of the high, drier pattern returns to
the area through the weekend. With high pressure in control through
Monday, winds remain light (

NWS DTX Office Area Forecast Discussion