Grosse Pointe Farms, Michigan Weather Forecast Discussion

328
FXUS63 KDTX 170733
AFDDTX
Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
333 AM EDT Wed Sep 17 2025
.KEY MESSAGES...
- Above average high temperatures continue through this weekend
aside from a brief return to near near normal temperatures Friday.
- Weak cold front Thursday brings a low chance (15%) to see an
isolated late day light shower. Otherwise, dry pattern persists
through this weekend.
&&
.DISCUSSION...
Extended dry, seasonably warm pattern continues as high pressure
remains centered over the central Great Lakes. As has been the case
the past several mornings, patchy fog developed late last night,
focused mostly in the Thumb, which will lingers into the morning
commute. Fog quickly dissipates by mid-morning setting up another
mostly sunny day with highs topping out in the low to mid 80s. While
skies clear out around sunset this evening, rex block over the
eastern CONUS fully breaks down allowing a weak northern shortwave
to drift out of the western Great Lakes into southern Ontario. High
cloud associated with this wave arrive late tonight preventing the
same level of radiational cooling as prior nights as lows hold in
the mid 50s which also should limit, if not prevent, another round
of early morning fog development.
A weak backdoor cold front follows the wave`s passage, dropping
through SE MI latter half of the day Thursday. In advance of the
front, lower level flow turns more westerly drawing in a piece of
richer theta-e airmass from the upper Mississippi into southern
lower MI pushing surface Td`s into the lower 60s. Overall forcing is
weak given the nature of the front and upper support focused over
southern Ontario by this point, however, increasing moisture
partially overlapping with peak heating looks to generate at least
of a few hundred J/kg of MLCAPE. With the bulk of model guidance
keying in on this setup and attempting to generate a few late day
showers, opted to add in slight chance mentions (15-20%) for the
afternoon thru late evening period. `Best` chances to see a light
shower currently look to occur north of M-59.
Modestly cooler Friday as the front settles south of the state
setting up northeasterly flow into SE MI. Given the winds off lake
Huron, the Thumb will be the coolest area with highs ranging from
near 60 on the lakeshore to upper 60s-near 70 inland. Areas south of
M-59 stand the see the warmest temps with highs still in the mid-
upper 70s to near 80 possible towards the Ohio border. Mid-upper
ridging then is re-established Friday night through the weekend
maintaining the dry pattern and above normal temps in the upper 70s
and 80s. Next chances to see wider spread rainfall won`t arrive
until Sunday night-Monday thru early next week.
&&
.MARINE...
A ridge of high pressure continues to bring an extended period of
dry weather and lighter winds to the Great Lakes through most of the
week. Winds continue to favor a light easterly component, with some
gradual backing to the south and then north tonight into Thursday. A
secondary high pressure system is expected to drop from the central
Canadian provinces into Ontario and Quebec late this week, which
will strengthen the pressure gradient over the Great Lakes region.
This will veer winds east to northeast and will bring some elevated
wind speeds across Lake Huron. Sustained winds 15 to 20 knots with
gust potential near 25 knots will be possible through the Saginaw
Bay and portions of southern Lake Huron to end the week.
&&
.PREV DISCUSSION...
Issued at 1157 PM EDT Tue Sep 16 2025
AVIATION...
High pressure will maintain VFR conditions through the early portion
of the night. The light to clam winds plus clear skies will likely
lead to fog development during the early morning hours that may bring
periods of MVFR to IFR VSBY as well as some IFR stratus off off the
lakes. MBS and FNT appear to be the more favored location for lower
VSBY restrictions. Confidence is low on exactly where denser fog sets
up. Conditions improve by around 13Z with high pressure continuing
to bring dry conditions and VFR skies. Flow turns north to northeast
tomorrow with potential for light easterly flow across the southern
metro terminals during the afternoon.
For DTW/D21 Convection...No thunderstorms expected through the TAF
period.
THRESHOLD PROBABILITIES...
* Low for ceilings at or below 200 feet between 09Z and 13Z
  this morning.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...None.
Lake Huron...None.
Lake St Clair...None.
Michigan waters of Lake Erie...None.
&&
$$
DISCUSSION...KDK
MARINE.......AM
AVIATION.....AA
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NWS DTX Office Area Forecast Discussion