280
FXUS63 KMQT 021501
AFDMQT

Area Forecast Discussion
National Weather Service Marquette MI
1101 AM EDT Wed Jul 2 2025

.KEY MESSAGES...

- Near to above normal temperatures persist through the work
  week and into the weekend. Humid conditions are likely to kick
  off the 4th of July weekend.

- Isolated to scattered thunderstorms are possible this
  afternoon and evening, mainly across the west and central UP.
  Some strong storms may produce gusty winds and small hail.

- Thunderstorms are possible in the afternoon and evening of
  Friday, the Fourth of July, as well as Saturday.

&&

.UPDATE...
Issued at 1100 AM EDT Wed Jul 2 2025

Quiet weather persists so far this morning, though smoke/haze from
Canadian wildfires has been able to reach the area and mix down to
the surface - at least across the northern UP. So, this has been
added to the forecast for the rest of today. Meanwhile, a weak
shortwave rippling through the Great Lakes has touched off
convection across northern MN. If this batch can hold together, it
may skirt the WI/UP border into the afternoon. Apart from that, some
additional spotty convection is still expected to develop in the
central and eastern UP as the wave moves through during the heat of
the day. Latest guidance still shows favorable conditions for some
stronger wind gusts and perhaps some small hail in the strongest of
storms. We`ll be watching.

&&

.SHORT TERM /THROUGH THURSDAY/...
Issued at 347 AM EDT Wed Jul 2 2025

Early morning RAP analysis/GOES satellite imagery reveal weak
ridging across the Upper Great Lakes and mostly clear skies
overhead. Upstream, a closed upper low is meandering through far
northern Ontario and pushing a diffuse cold front across western
ON/central Manitoba. A low-amplitude embedded shortwave is currently
kicking off a complex of showers and thunderstorms in far NW
Minnesota, and while guidance is not particularly optimistic on this
complex trekking into the UP, the incoming shortwave and weak
frontal boundary will be the focal point for showers and
thunderstorms development this afternoon.

As the embedded shortwave dives southeast into the northern Great
Lakes this afternoon, daytime heating will allow modest
destabilization upwards of 500-1000 j/kg MUCAPE. A belt of stronger
W/NW aloft will aid in effective shear values reaching 25-35 kts,
not overly strong but sufficient enough for storm organization.
Model soundings ahead of developing convection reveal very steep low-
level lapse rates associated with an inverted-V up to nearly 700mb,
pointing to potentially gusty downdrafts should organized storms
develop. Storm coverage is expected to be isolated to scattered at
best given weak synoptic support, with the current suite of CAMs
varying quite a bit on development across the western UP. Many of
the 00z CAMs (NAMNest, HRWs, and NSSL) spread scattered convection
from the western Lake Superior shores to northern Lake Michigan from
~16-22z, meanwhile the latest 06z HRRR/RAP runs suggest scattered t-
storms popping off in the western half as late as 21z then trekking
eastward through ~04z. Given the uncertainly, opted to throw
low chance PoPs across much of the west and central CWA through
most of the afternoon and evening. Otherwise, expect
temperatures to climb into the upper 70s and low 80s today.

As storms and showers clear behind the weak fropa/shortwave, another
calm night is in store with clearing skies and temps falling back
into the 50s. A building ridge across the central CONUS will
introduce high pressure atop the Great Lakes region Thursday,
keeping sunny skies and tranquil weather in the forecast.
Temperatures peak in the upper 70s and lower 80s across much of the
area, but light northerly flow may keep areas closer to Lake
Superior in the lower 70s for afternoon highs.

&&

.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
Issued at 347 AM EDT Wed Jul 2 2025

Friday, the 4th of July, mid-upper level ridge axis moves through
the Great Lakes, with the UP situated in strengthening
lower/midlevel southerly flow on the backside of the exiting ridge.
This will help to pump in a warmer airmass, and with a connection to
the Gulf, higher PWATs will be working into the region as well.
Meanwhile, deterministic and ensemble guidance continue to show
multiple shortwaves developing over the Plains and heading towards
the area during the day Friday through Friday evening. Will note
that differences in strength and timing persist among various model
guidance. Any earlier waves may bring showers and storms to the
region Friday afternoon and evening, but with the latest guidance
holding onto the ridge a little longer, confidence in this earlier
arrival time is decreasing. Still, with warm, moist, unstable
conditions (MUCAPE potentially in excess of 2000j/kg per LREF) and
an inverted-v shape to model soundings, any storms that can develop
during the afternoon and evening - whether forced  by passing waves
or simply diurnally-driven - could be on the stronger side.
Confidence in (potentially strong) convection increases Friday
evening and into the night as a more energetic shortwave heads
towards the area, while we end up near the exit region of a
strengthening LLJ. Afterwards, timing and spatial differences become
more pronounced, but eventually a cold front moves through the area
sometime Saturday through Saturday evening. This brings with it more
chances for convection, again potentially on the stronger side with
healthy daytime instability potentially around/in excess of
1000j/kg. Dry weather returns into early next week behind the front.

Otherwise, expect hot and muggy conditions through the holiday with
temperatures Friday and Saturday peaking well into the 80s for much
of the UP. Dewpoints ranging in the 60s and even to near 70F will
lead to heat indices near 90F both days. Temperatures turn more or
less seasonal behind the cold front.

&&

.AVIATION /12Z TAFS THROUGH 12Z THURSDAY/...
Issued at 732 AM EDT Wed Jul 2 2025

VFR conditions will be the rule today (save for for a brief period
of MVFR vis being reported at IWD at the time of writing this, which
should clear out early this morning). The main aviation concern will
be the development of scattered showers and storms this afternoon
ahead of a weak cold front. Guidance is rather inconsistent on the
timing and placement of -shra/tsra with some depicting the main ESE
moving line skirting past all terminals between ~19-21z, however, a
few hourly CAM runs are holding back on convective development until
later this evening, thus opting for a longer prob30 group for -tsra
at IWD and SAW. Confidence in anything reaching CMX is low enough
<20%) to leave out of the TAF. Additionally, a few gusty W to NW
winds >15 kts may be observed.

&&

.MARINE...
Issued at 341 PM EDT Tue Jul 1 2025

Gusty SW winds to 15-25 kts with waves up to 4 ft this evening will
subside tonight with winds below 20 kts and waves less than 4 ft
expected after midnight. W to SW winds rise to ~15-20 kts again over
the W half of the lake on Wednesday before becoming light (mainly 15
kts or less) and variable for Thursday. Southerly winds gradually
increase to 20 kts on Friday, remaining elevated into the weekend.

&&

.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
None.
Lake Superior...
None.
Lake Michigan...
None.

&&

$$

UPDATE...LC
SHORT TERM...BW
LONG TERM...LC
AVIATION...BW
MARINE...Jablonski/PK