317
FXUS63 KMQT 160531
AFDMQT

Area Forecast Discussion
National Weather Service Marquette MI
131 AM EDT Tue Jul 16 2024

.KEY MESSAGES...

- Marginal risk (category 1 out of 5) of severe thunderstorms today
mainly from 4-10 pm EDT. Main threat is damaging winds and large
hail.

- Cooler and drier for midweek with the arrival of high pressure.

&&

.SHORT TERM /THROUGH TODAY/...
Issued at 1254 PM EDT Mon Jul 15 2024

Early afternoon water vapor imagery shows a midlevel anticyclone
centered around the Four Corners and a cutoff low just southwest of
Hudson Bay. Stronger 500 mb flow between these features is spreading
eastward into the Upper Great Lakes, with a notable shortwave trough
now progressing into northern MN. High convective debris clouds are
spreading into the local area ahead of this feature and also along
the northern periphery of a decaying MCS over southern MN/WI, but
there is some clearing noted over northern WI where some lower cu is
developing. Gradual moistening is taking place over the western UP
where dewpoints are creeping back up into the low to mid-60s.
Surface pattern is a bit messy, but there is a cold front apparent
from roughly Thunder Bay SWWD to about Fergus Falls, MN.

Modest destabilization ahead of the incoming wave/cold front should
continue over roughly the SW half of the UP this afternoon due to
clearing skies and weak advection of better low-level moisture.
Despite midlevel lapse rates decreasing to less than 7 C/km, this
should allow for the development of 1000-1500 J/kg MLCAPE just ahead
of the incoming disturbances. Further north toward the Keweenaw,
Marquette area and points east, destabilization is less certain with
MLCAPE likely remaining less than 1000 J/kg. Deep-layer shear does
look good, increasing to 40-45 kt. Low-level winds are a bit more
modest and may actually decrease a bit ahead of the front, leaving
low-level convergence a question-mark. Still, high confidence in a
rather quick-moving area of showers and thunderstorms moving across
the UP from west to east this afternoon, primarily 4-10 pm EDT.
Marginal risk (category 1/5) for severe weather with a few storms
capable of damaging winds and large hail. Risk appears highest south
of a line from roughly Manistique to Ontonagon.

Cold and dry advection ensues tonight, ushering out the seasonably
warm airmass of the last couple days. Skies clearing with lows in
the mid-50s to near 60.

&&

.LONG TERM /TUESDAY THROUGH MONDAY/...
Issued at 302 PM EDT Mon Jul 15 2024

Upper troughing over far northern Ontario will continue to dig
southward across Lake Superior on Tuesday. While drier air will be
slowly working it`s way into the area behind Monday`s frontal
passage, shortwave energy rotating around the trough may help
initiate a few diurnal showers across the interior west and south
central. Temperatures will be seasonable in the 70s on Tuesday.

Main upper trough axis pushes through the U.P. late Tuesday night
and Wednesday with a reinforcing cold frontal passage. Limited
moisture will limit rain chances but some sprinkles/-shra will be
possible late Tuesday night through Wednesday morning. Expect a
broken stratucu deck to last into the afternoon hours with a
persistent northwesterly breeze.  Nearshore Lake Superior water
temperatures are now in the 60s and that`s where temperatures will
hold for Lake Superior bordering counties given northwest flow and
considerable clouds hanging on into the afternoon. Highs inland
should climb into the lower 70s, especially later in the day as
clouds dissipate.

Ridging over the northern Plains will build into the Upper Lakes
Wednesday night. Clear, calm conditions will allow temperatures to
fall to near 40 for interior cooler location`s...perhaps a few upper
30s. Temperatures will be milder in the 50s near the shorelines.

High pressure and seasonable temperatures under lots of sunshine
will be the theme for Thursday and Friday.

An upper trough dropping southeast into Ontario and Quebec will push
a mainly dry front southward across Lake Superior on Saturday with a
wind shift to the north and slightly cooler day, especially near
Lake Superior. High pressure returns for Sunday into early next week
with near normal temperatures.

&&

.AVIATION /06Z TAFS THROUGH 06Z WEDNESDAY/...
Issued at 131 AM EDT Tue Jul 16 2024

Overnight flight restrictions due to earlier showers and
thunderstorms should be mostly confined to KSAW and KIWD, where IFR
fog/mist will be possible. Expect any to mix out with the sunrise
and all sites to be VFR for Tuesday. Some gusty winds may develop by
afternoon at KSAW and KCMX.

&&

.MARINE...
Issued at 302 PM EDT Mon Jul 15 2024

A cold front crossing the Lake late this afternoon and evening will
trigger some showers and thunderstorms, but they will end by late
evening. Where rain occurs, patchy dense fog will be possible
before being pushed eastward on west northwesterly post frontal
flow. Westerly winds may gust in excess of 20 knots on Tuesday
especially along the west side and tip of the Keweenaw. As upper
trough axis swings across Lake Superior Wednesday morning, winds
will turn more northerly and could gust in excess of 25 knots for a
time, especially over the eastern Lake.  Winds will diminish by
Wednesday evening as ridging builds across the Lake and will remain
below 20 knots into early next week. A front sagging southward from
Ontario will yield a wind shift to the north on Saturday...otherwise
winds will be predominantly from a west and southwest direction.

&&

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

&&

$$

SHORT TERM...Thompson
LONG TERM...MZ
AVIATION...JTP
MARINE...MZ