092
FXUS63 KMQT 110820
AFDMQT

Area Forecast Discussion
National Weather Service Marquette MI
420 AM EDT Tue Jun 11 2024

.KEY MESSAGES...

- Chilly and dry again tonight with high pressure overhead.
  Frost is possible.

- A couple rounds of showers and thunderstorms expected Tuesday
  afternoon through Thursday night. This will be accompanied by
  generally warmer than normal temperatures that continue into
  the weekend.

- Strong and potentially severe storms look possible Wednesday
  afternoon and evening across the west half of Upper Michigan.

&&

.SHORT TERM /THROUGH THIS AFTERNOON/...
Issued at 420 AM EDT Tue Jun 11 2024

Currently it`s cool and quiet outside as mid level ridging moves
over the Upper Great Lakes and high pressure settles southeast
through the area. With only a few high clouds passing east over the
UP ahead of the next system and a dry and chilly airmass overhead,
radiative cooling has allowed for temps for much of the UP to drop
into the 30s with low to mid 40s near the lakeshores. Temps will
continue to settle a few more degrees yet before sunrise, letting
more spots approach low to mid 30s. With the calm conditions,
widespread frost is still expected away from the lakeshores.

Moving on to the rest of today, the broad trough currently analyzed
over Saskatchewan and Manitoba shifts east toward Ontario. The
southern shortwave embedded in this trough rotates northeast from
southern Manitoba to far northwestern Ontario through this period,
supporting a similar northeastern track for the associated sfc low.
This results in some weak PVA and isentropic ascent late morning
into the afternoon over the west as the mid level ridge breaks down.
The antecedent dry airmass from the high pressure likely will hold
of showers until around noon in the far west, with showers
progressing east across the UP through the afternoon ahead of the
sfc low`s occluded front. Given the weak forcing and lack of
instability/shear during the daytime hours (bulk shear peaking at
~30kts with MUCAPE below 250 J/kg), thunder should hold off until
the evening hours. Mixing will result in some breezy southerly winds
today with gusts up to 20-25 mph, strongest in the far west. Highs
for the day are expected in the upper 60s to low 70s.

&&

.LONG TERM /TUESDAY THROUGH MONDAY/...
Issued at 319 PM EDT Mon Jun 10 2024

Overnight ridging will breakdown Tuesday as a shortwave and surface
low press through Manitoba and into Ontario. By evening, an
associated weakening cold/occluded front will press into the western
UP. Ahead of the boundary by mid-late afternoon, showers with some
embedded thunderstorms will press into western Upper Michigan, then
continue east through the U.P. overnight as activity wanes. Guidance
suggests instability will be limited (MLCAPE of 500 j/kg or less),
so strong to severe storms are not expected. Daytime highs Tuesday
should climb to near 70F while overnight lows Tuesday night only dip
into the low 50s.

Near-zonal flow with a couple embedded shortwaves will follow across
the northern Tier into the Great Lakes. While these shortwaves
progress close or through the Great Lakes, prevailing southerly low-
level flow and warm air advection will support increased warming
Wednesday and Thursday. This warm and moist airmass could support a
couple rounds of showers and thunderstorms as these shortwaves press
into the region Wednesday and Thursday. Beginning with a breakdown
of Wednesday, a weak shortwave/PVA stream will move west to east
through Lake Superior and Upper Michigan through the day. A 850mb
LLJ to near 30-35kts alongside a jet exit region by afternoon may
support large scale ascent and deep layer shear of 50-60kts. While
the NAM is certainly an outlier with its 2-3k j/kg MLCAPE, the
general consensus of 500-1000j/kg MLCAPE across the west half with
the wind profile may support some strong or severe thunderstorms. It
should be noted that the better forcing is expected to be south and
west of the region, but steep mid-level lapse rates present in NAM,
NAM3k, and GFS soundings suggest that if something does develop in
our area, hail and stronger winds will be possible. Initial timing
among the various deterministic systems suggest earliest onset would
be in the afternoon in the west, but there`s a better signal for mid-
late afternoon in the west, then increasing coverage in the evening
U.P.-wide.

By Thursday morning, another shortwave looks to press southeast
through Lake Superior while a surface low lifts north through
Ontario. There`s timing differences among the models as to when the
trailing cold front will press through Upper Michigan, but the
general consensus is that the front should clear the region by
afternoon. Similarly to Wednesday, the strongest instability is out
of our forecast area, but strong deep layer shear would be enough to
support strong storms if they materialize ahead of the boundary.
Post frontal dinural mixing may also support a gusty day on
Thursday. Steeping low level lapse rates may be able to mix up into
strong winds a loft. At the moment, current forecast is for 20-25
kts, but this may trend up in future forecasts. Another shortwave
may follow Thursday night into early Friday, but confidence is low
(<25%) at this point.

Both Wednesday and Thursday, daytime highs may climb to the upper
70s or low 80s with overnight lows mostly in the 50s. Cooler airmass
builds in for Friday which will support highs in the upper 60s to
mid 70s. This is expected to be brief given guidance`s suggestion of
a warming trend going for the weekend and into next week.

&&

.AVIATION /06Z TAFS THROUGH 06Z WEDNESDAY/...
Issued at 125 AM EDT Tue Jun 11 2024

VFR prevails at all terminals for most of the forecast period. Apart
from some stray high cirrus spilling into the area, skies are mostly
clear across the UP. However, clouds thicken and lower into Tuesday
with an approaching disturbance. This should bring in some scattered
showers, and perhaps a rumble of thunder, from west to east during
the afternoon and evening Tuesday. Some MVFR restrictions are
possible. Otherwise, expect shifting winds this evening to turn to
the south into Tuesday, with some gusts around 20kts possible
especially at IWD.

&&

.MARINE...
Issued at 319 PM EDT Mon Jun 10 2024

High pressure over the region has supported winds mainly 20kts or
lower across Lake Superior. A series of fronts will move through the
lake Tuesday - late Thursday. Ahead of these fronts, southerly winds
may support 20-25kt winds and showers and thunderstorms. Strongest
storm potential will be Wednesday afternoon and evening across
western Lake Superior. High pressure builds in on Friday, returning
dry and calmer conditions with winds below 20kts to start of the
weekend.

&&

.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
  Frost Advisory until 8 AM EDT /7 AM CDT/ this morning for
     MIZ002>007-009>014-084-085.

Lake Superior...
None.
Lake Michigan...
None.

&&

$$

SHORT TERM...Jablonski
LONG TERM...JTP
AVIATION...LC
MARINE...JTP