464
FXUS63 KMQT 140910
AFDMQT

Area Forecast Discussion
National Weather Service Marquette MI
510 AM EDT Sun Jul 14 2024

.KEY MESSAGES...

- Seasonably warm again this afternoon with a 20-30% chance of
  showers/thunderstorms in lake-breeze convergence zones.

- Marginal risk (category 1 out of 5) of severe thunderstorms on
  Monday, main threat is damaging winds.

- Cooling and drying trend into the midweek portion of next week
  with the arrival of high pressure.

&&

.SHORT TERM /THROUGH THIS AFTERNOON/...
Issued at 509 AM EDT Sun Jul 14 2024

Radar mosaic is quiet early this morning across Upper Michigan with
all reflectivity returns concentrated over Wisconsin and far eastern
Upper Michigan.  And, will continue with this trend through Sun 12Z
under a rather stable environment.  At that point, have ~20% chance
Pop mention over the eastern portions of the forecast area through
the morning, but this is low confidence as CAMs continue to struggle
with consistency in the short term.  As a result, highly likely that
even those Pops will be removed with future updates.  For now,
highest confidence for any convective development is within the lake-
breeze convergence zones later this afternoon, which would have just
enough instability to initiate some pop-up thunderstorm activity in
the hot and muggy environment.  With daytime highs progged to top
off in the mid to upper 80s once again and widespread dew
points in the 60s, SBCAPE values will climb into the 1000-2000
J/kg range. So, any weak perturbations/lake-breezes that do form
will have a chance at convective development.

&&

.LONG TERM /TONIGHT THROUGH SATURDAY/...
Issued at 456 AM EDT Sun Jul 14 2024

Starting tonight, lingering showers and storms over the east from
the lake breeze will drift southeast over Lake Michigan leaving dry
weather for the UP through Monday morning behind a cold front. Lows
fall into the upper 50s to mid 60s with light winds and mostly
clear skies.

Moving onto Monday, our next shortwave trough over MN and Manitoba
swings through the region. A sfc low develops off the Rockies into
the northern Plains Sunday night. This low moves east toward Upper
MI and Lake Superior for late in the day monday, continuing into
Quebec by Tuesday afternoon. This brings another round of showers
and storms across the UP ahead of a cold front. Bulk shear
significantly increases to 40-45 kts (7/14 0Z LREF mean) with the
passing shortwave supporting organized convection. Monday will be
another warm day as well with highs in the upper 70s to mid 80s and
ample moisture as dew points hang around the mid 60s and PWATs
increase to around 1.5"(~90th percentile of the GRB sounding
climatology). This should allow for some instability, yielding weakly
capped SBCAPE ~500-1000 J/kg; mid level lapse rates struggle to
reach 6C/km. Although the instability is not impressive, the forcing
is good, so thunderstorms are expected with a few being potentially
strong to severe, consistent with the SPC Marginal Risk (category 1
of 5). Given the orientation of the shear with the cold front, a
more linear mode is expected leaving the main threat with any severe
storms to be damaging winds.

A drier airmass moves in Monday night into Tuesday behind the cold
front, diminishing precip and cloud cover. Lows are expected in the
mid 50s to low 60s.

Tuesday and Wednesday, the positively tilted mid level trough over
northern Ontario becomes more vertically oriented as it pivots over
the UP before swinging east toward Quebec and New England for late
next week. This should support some light northwest winds gusting up
to 20 mph, increased cloud cover accompanied by some light showers
and maybe a rumble of thunder on Wednesday, and cooler temps. Highs
on Tuesday stay in the 70s while Wednesday cools off even more with
highs only in the mid 60s to low 70s. Lows Tuesday and Wednesday
night dip into the 40s in the interior with 50s near the lakeshores.

High pressure then builds in from the west Wednesday, continuing to
shift over the Great Lakes through the rest of the week and next
weekend. This results in a gradual warming pattern late next week
into the weekend with dry weather. Model guidance begins to diverge
next weekend, specifically regarding when precip returns. Likely,
any precip will be supported by a shortwave dropping southeast
through the region. However, deterministic solutions of the
Canadian/ECMWF/GFS all show additional high pressures shifting back
into the region again next week with mid level ridging finally
moving east toward the midwest. So, the dry pattern may only be
briefly interrupted as it continues into the following week.

&&

.AVIATION /06Z TAFS THROUGH 06Z MONDAY/...
Issued at 124 AM EDT Sun Jul 14 2024

Upstream convection has been observed in Minnesota and Ontario on
DLH radar. As of this writing, convection has mostly been scattered
in nature and continues to grow upscale into a line as it presses
southeast across Lake Superior and northern Wisconsin. Terminals
that are most likely to see showers and maybe a thunderstorm are
KIWD and KCMX. At KSAW, early period vicinity showers will continue,
but thunderstorms aren`t expected. As the upstream wave moves
through Upper Michigan, its unclear if it will hold together enough
to impact KSAW. If it does, timing currently looks like early-mid
morning. Outside of convection, VFR conditions are expected in this
TAF period.

&&

.MARINE...
Issued at 456 AM EDT Sun Jul 14 2024

Very light southerly winds below 15 kts this morning become west to
southwest by the afternoon as a cold front progresses across the
lake. Winds are generally expected to remain below 20 kts during
this period, however the strongest winds up to 20 kts are expected
between Isle Royale and the Keweenaw. Winds turn very light again
tonight through Monday morning. A round of storms is expected Monday
into Monday night as a low pressure system moves through the area.
Patchy dense fog is a possibility in the wake of any precipitation.
Following the low pressure system`s cold front, northwest to west
winds increase to around 15-20 kts across much of the lake Monday
night and Tuesday. After another period of 15-20 kt northwest winds
on Wednesday, high pressure begins to build in from the west
resulting in winds to remain below 20 kts through the remainder of
the forecast period.

&&

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

&&

$$

UPDATE...
SHORT TERM...TDUD
LONG TERM...Jablonski
AVIATION...JTP
MARINE...Jablonski