830
FXUS63 KMQT 250901
AFDMQT

Area Forecast Discussion
National Weather Service Marquette MI
501 AM EDT Tue Jun 25 2024

.KEY MESSAGES...

-Non-severe thunderstorms push east through this morning.

-Today will be a warm and windy day, with highs around 80 and
 wind gusts up to 30-40 mph in the west.

-Pattern remains active, especially from late week into early
 next week, with yet more rounds of showers and storms

&&

.SHORT TERM /THROUGH TONIGHT/...
Issued at 500 AM EDT Tue Jun 25 2024

Thunderstorms are ongoing this morning throughout western and
central Upper Michigan. A few of these storms have been producing
hail, though the largest report thus far has been pea sized hail in
Ironwood. Perhaps more perplexing has been the wind gusts, with
storms on Isle Royale and the Keweenaw Peninsula gusting above 50
mph, though the wind threat has fallen significantly since the time
storms initially passed through that area. These showers and
thunderstorms are forecast to continue pushing east through the rest
of the morning, with 00Z HREF hourly PoPs falling below 30% UP-wide
by 14Z.

As winds veer westerly behind the front, soundings show a 30+ kt jet
at 850mb that can be mixed into, leading to a gusty day expected,
especially over the west and particularly the Keweenaw. By 21Z, the
HREF shows 70-100% chances of wind gusts over 30 mph over the west
half and along Lake Superior in the east, with the Keweenaw showing
40-90% probabilities of gusts over 40 mph. It will also be a warm
day, with MOS guidance showing wide swaths of the south-central UP
reaching into the mid 80s for highs today, with the NBM showing
about a 25% chance that the M-35 corridor from Escanaba to Menominee
could touch 90 today.

Overnight, clear skies will begin to cloud up some, though enough
radiational cooling should occur to allow low temperatures to fall
below 50 away from the Great Lakes. A very subtle 500mb shortwave
will be pushing southeast from northwest Ontario, reaching the
western UP by 12Z Wednesday. Just enough forcing and moisture will
be present for slight-chance (15-30%) PoPs over the west half,
though precipitation will be struggling against the near-1015
surface high pressure present at the time, so impacts of any showers
will be light, if any.

&&

.LONG TERM /WEDNESDAY THROUGH MONDAY/...
Issued at 408 AM EDT Tue Jun 25 2024

Starting Wednesday, a northwest flow shortwave and associated cold
front moves from the Northern Plains across the Upper Great Lakes.
Most of the models show an inverted sfc trough inflection associated
with the shortwave from northern WI along the U.P. border.
Instability is limited at 200 j/kg or less so expect isolated to
scattered showers Wednesday, probably focused mainly west and along
the WI border where the inverted sfc trough axis is situated. Expect
drying and clearing skies from the west and north behind the
shortwave trough and cold front in the afternoon into early evening
as highs peak mainly in the 60s. However, those near the eastern
Lake Superior shores may stay in the 50s throughout the day.

Weak high pressure ridging persists across the region from Wed night
into at least Thu evening, dry weather prevails. Under clear skies
and near calm winds, radiative cooling will drop Wed night lows into
the 40s, coolest over the interior. Expect highs Thu generally
in the lower to mid 70s.

Meanwhile, a trough just east of the Pacific northwest will move
onshore Wednesday night. This trough progresses east along the
international border toward the Upper Great Lakes by Saturday
morning with at least a couple of shortwaves embedded in it. This
will support cyclogenesis in the northern Rockies Thursday night
with the low ejecting east into northern Ontario Friday
night/Saturday. WAA/isentropic ascent and theta-e advection ahead of
the low will support showers and thunderstorms spreading into Upper
Mi on Friday. The first of the shortwaves within the mid-level
trough moves through Sat which pushes a cold front through the area
Fri night into Sat. Increased instability noted along the cold front
should increase chances for thunder as it moves through the area at
this time. The second shortwave in the trough will send a secondary
cold front and another round of showers across the area late Sat
into early Sun along with a burst of gustier nw-n winds and colder
temps.

High pressure building in quickly behind the front will result in
drier, albeit cooler conditions Sunday afternoon into Monday. Models
advertise another shortwave and associated sfc low lifting off the
Northern Rockies and tracking e across the Northern Plains and
Canadian Prairies into the Upper Great Lakes for early next week.
This feature will bring another round of showers/t-storms into the
area for next Mon night into Tuesday.

&&

.AVIATION /06Z TAFS THROUGH 06Z WEDNESDAY/...
Issued at 129 AM EDT Tue Jun 25 2024

VFR conditions will prevail early this period, followed by a rapid
deterioration as a line of thunderstorms moves into Upper Michigan.
Expecting most activity between 06Z and 11Z, with the greatest
potential for severe winds, maybe some large hail, at KIWD early on
in the event. Expect ceilings to fall to MVFR/IFR after the line
moves through with some brief fog/mist developing before the
sunrise. Tuesday, gusty winds are expected to develop as ceilings
improve. Initial thoughts are KCMX could gust near 30kts from the
west. LLWS will occur overnight at IWD and SAW.

&&

.MARINE...
Issued at 408 AM EDT Tue Jun 25 2024

Thunderstorms tracking across eastern Lake Superior along a cold
frontal passage will bring somewhat gusty winds and lightning to
mariners over the eastern lake early this morning. Winds will shift
from southerly to westerly winds behind the cold front later this
morning while gusting as high as 30 kts. Strongest winds are
expected over the central portion of the lake as fcst soundings and
model guidance suggest a (20-30%) potential for west gale gusts to
35 knots, especially at higher platform locations like Stannard
Rock. This period of longer fetch and stronger winds will help waves
build up to 4-6 feet this afternoon and evening north of the
Keweenaw. Winds around 20-25 kts veer north tonight behind an
additional cold front that drops south across the lake before
tapering off below 20 kts Wednesday morning. With high pressure over
the lake through Thursday, winds are expected to mainly remain below
20 kts. A weakening low pressure tracking through the Upper Great
Lakes early this weekend will allow for s-se gusts near 20 kt Friday
and 20-25 kt nw gusts behind a cold frontal passage Saturday before
building high pressure returns Sunday and ushers in lighter winds.

&&

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

&&

$$

SHORT TERM...GS
LONG TERM...Voss
AVIATION...07
MARINE...Voss