585
FXUS63 KMQT 020510
AFDMQT

Area Forecast Discussion
National Weather Service Marquette MI
110 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 and scattered thunderstorm activity is possible
Wednesday. Thunderstorms are also possible in the afternoon and
evening of Friday, the Fourth of July as well as on Saturday.

&&

.SHORT TERM /THROUGH WEDNESDAY NIGHT/...
Issued at 341 PM EDT Tue Jul 1 2025

Afternoon RAP analysis shows the UP on the eastern periphery of a
midlevel ridge building over the Plains, with low-amplitude
troughing extending into the Great Lakes as low pressure remains
centered near James Bay. A subtle shortwave tracking through
northern Ontario has kick off convection just north of the MN border
and in northern Lake Superior. This may be able to reach into our
waters and even graze the northern UP later today, though confidence
is low. Otherwise, closer to home, patchy, low-topped, fair-weather
cumulus across much of the interior UP betrays decent afternoon
destabilization. This is helping to mix down some ~20mph gusts at
times, otherwise quiet weather persists across the area today with
highs ranging in the lower 80s. Nearer to Superior, onshore flow is
keeping temperatures slightly cooler, in the 70s. Quiet weather
continues tonight, with temperatures falling back into the mid/upper
50s under mostly clear skies.

Wednesday, we remain on the eastern edge of the ridge while a deeper
trough/midlevel low drops through Ontario. As an initial associated
shortwave drops through Wednesday afternoon ahead of the main trough
axis Wednesday evening into the night. The initial shortwave, as well
as any lake breeze interactions, will support a window for scattered
convection to sweep through during the afternoon and evening.
Several hundred to 1000j/kg of CAPE is indicated in soundings, as
well as deeply mixed, inverted-V soundings that show us tapping into
stronger ~30kt winds aloft. With an unstable environment and
sufficient shear present to sustain thunderstorm updrafts, some
marginally-severe storms with hail and gusty winds will be possible.

Thunderstorms wrap up Wednesday evening, then expect a quiet night
while temperatures fall back into the mid/upper 50s under clear
skies.

&&

.LONG TERM /THURSDAY THROUGH TUESDAY/...
Issued at 341 PM EDT Tue Jul 1 2025

The long term period starts off with quiet weather for Thursday with
steep mid/upper level ridging centered over the Plains. This
supports surface high pressure downstream over the Great Lakes.
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.

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