Copper City, Michigan Weather Forecast Discussion

627
FXUS63 KMQT 281140
AFDMQT
Area Forecast Discussion
National Weather Service Marquette MI
740 AM EDT Sun Sep 28 2025
.KEY MESSAGES...
- A mostly dry and low impact weather pattern with near to above
average temperatures holds into next week.
- RH as low as 25-30% is possible this afternoon and again
  Monday afternoon, especially away from the shorelines.
&&
.DISCUSSION...
Issued at 339 AM EDT Sun Sep 28 2025
An upper level low pressure remained over the Hudson bay with upper
level ridging over the central U.S and a more zonal flow over
southern Canada. A weak shortwave was bringing some cloudiness to
the area overnight, mainly over Lake Superior and the eastern U.P.
Temperatures ranged from the upper 30s to the low 40s where the
boundary layer had decoupled over interior sections and the south-
central U.P, along the immediate Lake Superior shoreline it was as
warm as 60 with light onshore flow.
It will remain dry and warm today and Monday as the upper level
ridge continues to build over the central U.S. Highs today and
Monday will reach well into the 70s with areas over the west
approaching 80F on Monday. Dry low and mid levels along with deep
mixing today will help bring RH down to near 25% today away from the
shorelines. Monday will again see deep mixing through we start to
see moisture return into the area so RH will be slightly higher, as
low as 30%. The NBM is struggling with the surface moisture both
days; underforecasting the impact of the mixing on the low levels.
Deviated from the NBM both days (during the daylight hours) to lower
the dewpoints and RH.
The upper level ridge axis shifts east, centered over the Great
Lakes early to midweek. Shortwave energy will round the ridge
Tuesday into Wednesday bringing high levels clouds into the area but
very dry air in the mid levels will prevent any precipitation. While
still above average, temperatures will cool a bit for Tuesday and
Wednesday (especially in the eastern U.P) as high pressure builds
into Quebec and a backdoor cold front pushes into the area from the
northeast. Temperatures will remain warm through the week with
mainly 70s except for Tuesday and Wednesday with mid to upper 60s
over the central and east.
The NBM maintains low PoPs coming back into the picture late this
week as the ridge begins to flatten out and shortwaves skirt through
the region.
&&
.AVIATION /12Z TAFS THROUGH 12Z MONDAY/...
Issued at 739 AM EDT Sun Sep 28 2025
VFR conditions and light winds expected throughout TAF period as an
upper level ridge continues to strengthen over the central U.S. Will
not carry mention of fog, either.
&&
.MARINE...
Issued at 223 PM EDT Sat Sep 27 2025
West-southwest winds of around 25 knots are expected over the lake
between the Keweenaw and Isle Royale the rest of this afternoon into
this evening behind the `cold` front passing through this afternoon.
While we could see westerly gusts above 20 knots for a few hours
late tonight over the open eastern lake, with high pressure building
back in expect winds to dwindle to 20 knots or less again late
tonight/early Sunday morning. As a subtle, non-precipitating
shortwave moves through on Sunday, expect west-southwest winds of 20
to 25 knots to return between the Keweenaw and Isle Royale. While
light winds of 20 knots or less are expected Monday, with sfc
troughing setting up over the Northern Plains from Tuesday onwards,
expect east to southeasterly winds of 20 to 25 knots to develop over
the lake Tuesday and Wednesday, eventually becoming southerly on
Thursday.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
None.
Lake Superior...
None.
Lake Michigan...
None.
&&
$$
DISCUSSION...NL
AVIATION...TDUD
MARINE...TAP

NWS MQT Office Area Forecast Discussion