Montrose, Michigan Weather Forecast Discussion

524
FXUS63 KDTX 140357
AFDDTX
Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
1157 PM EDT Sat Sep 13 2025
.KEY MESSAGES...
- Patchy to areas of fog in the morning, especially near the
  shoreline of Lake Erie and Lake St. Clair.
- Much above normal highs with continuing dry weather next week.
&&
.AVIATION...
Sky has cleared along the terminal corridor and over all of SE Mi
outside of a few pockets of mid level clouds toward the Ohio border
and toward Saginaw Bay leading up to midnight. Diffuse surface
pressure and light/variable to calm wind accompany the clear sky to
promote narrowing T/Td spread favorable for fog development. The
scenario has standard onset, density, and duration challenges
leading into MVFR and approaching IFR at times toward sunrise. The
DTW corridor appears most susceptible to lower visibility depending
on late developing surface or boundary layer wind having a SE
component off Lake Erie. Patches of mid level clouds near MBS aside,
full sun brings quick improvement early in the morning. High pressure
is then reinforced from Ontario and Lake Huron during the day
signaled by light easterly wind picking up slightly from the NE into
Sunday evening.
For DTW/D21 Convection... Weather conditions do not support
thunderstorms for the next several days.
THRESHOLD PROBABILITIES...
* None.
&&
.PREV DISCUSSION...
Issued at 326 PM EDT Sat Sep 13 2025
DISCUSSION...
SE Michigan resides at the inflection point of low pressure near
Hudson Bay and high pressure building over the Plains. The influence
of the trough was noted in the 12z KDTX RAOB as a 500mb height of
583 dam was sampled at KDTX and 580 dam at KAPX. Showers that were
generated by this system have since departed southeast, although
remnant cloud cover remains as a pocket of mid-level moisture and
isentropic ascent glance across the area. Cloud cover should slowly
erode this evening in favor of clear skies and radiative cooling
overnight under the stable subsidence inversion. Dewpoints this
afternoon have been notably higher than most of the hi-res guidance,
suggesting patchy fog may be more aggressive than what models are
currently predicting. While current grids reflect fog near the
shoreline, this may need to be expanded inland depending on
moisture/cloud trends through the evening.
Heights build Sunday through Tuesday as a seasonably strong ridge
axis slides into SE Michigan and surface high pressure fills in from
Ontario. 90-100% of LREF members predict 500mb heights above 588
dam, which is in the 90th percentile per SPC climatology. The
building ridge transitions to a rex block as an upper low deepens
over SE CONUS, with the overhead ridge effectively stalling multiple
upstream waves west of the Mississippi River to ensure dry weather
through mid-week. This will also support seasonably warm conditions
with daytime highs comfortably climbing into the 80s under plenty of
solar insolation.
By mid-week, the ridge begins to break down as a cluster of
shortwaves organize into an upper low over the Dakotas and central
Canada. Predictability in the synoptic pattern lessens through the
rest of the week as these waves interact, with the complicated
phasing of these features offering many possible scenarios. In
general, expect a period of height falls and increased moisture by
late week-next weekend. Ensemble member statistics show a marked
increase in variance by the weekend, favoring a cool down and
chances for rain.
MARINE...
A ridge of high pressure will build in through Sunday and will hold
through the the middle of the week, bringing an extended period of
dry weather along with light winds. Winds direction will turn more
uniform through the day tomorrow from the northeast, bringing some
localized elevated gusts nearing 20 knots into the Saginaw Bay.
These localized higher winds will subside through Monday morning.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...None.
Lake Huron...None.
Lake St Clair...None.
Michigan waters of Lake Erie...None.
&&
$$
AVIATION.....BT
DISCUSSION...MV
MARINE.......AM
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NWS DTX Office Area Forecast Discussion