469
FXUS63 KMQT 020748
AFDMQT

Area Forecast Discussion
National Weather Service Marquette MI
348 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.

&&

.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 ~02z. 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 /06Z TAFS THROUGH 06Z THURSDAY/...
Issued at 110 AM EDT Wed Jul 2 2025

VFR conditions are expected to continue the rest of today into this
evening, although there is a small (15% or less) chance that we
could see degradations below VFR due to showers and storms
developing over the U.P. during the daytime today, namely over IWD
and SAW. There is also a small (20% or less) chance that we could
see FG begin to form at CMX and SAW at the end of the TAF period
late tonight. Generally, mostly light W to NW flow dominates today,
but we could see the lake breeze influence the winds over SAW late
this afternoon behind the convection.

&&

.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.

&&

$$

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