568
FXUS63 KMQT 110953
AFDMQT

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

.KEY MESSAGES...

- A couple rounds of showers and thunderstorms expected this
  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 /TONIGHT THROUGH MONDAY/...
Issued at 541 AM EDT Tue Jun 11 2024

Convective activity will return for the first half of the extended
period as temperatures return to more of a summer pattern.
Immediately, ongoing showers will be possible this evening as a
cold/occluded front continues its progression across Upper Michigan.
And, with a little burst of instability, some rumbles of thunder can
be expected into tonight, mainly west and central. But, with
guidance suggesting MUCAPES struggling to get above 250 J/kg, storms
will struggle to maintain much if any intensity after Wed 06Z.  By
Wed 09Z, almost all of the forecast area will be rain and
thunderstorm free with a brief lull in activity before the next
shortwaves enter the area.

The first of two shortwaves is progged to enter Upper Michigan on
Wednesday, advecting dewpoints in the mid to upper 50s and warm air
(temps in the low to mid 80s) ahead of it.  Despite the best
instability being south and west of the UP, MLCAPE values could
still reach the 500-1000j/kg range over the southwest UP.  And,
forcing in the exit region of a 50-70 kt mid-level jet combined with
a surface cold front could be sufficient enough to generate some
strong to severe thunderstorms mid to late afternoon (west) and over
the remainder of the UP through the evening hours.  Again, best 0-3
km storm-relative helicity will remain south and west of Upper
Michigan.  But, mid-level lapse rates in excess of 6 C/km over
portions of Upper Michigan suggest that large hail could be a threat
from any storms that do become severe.

Thursday, the second of the two shortwaves will combine with a
surface low propagating through the region to generate additional
thunderstorm chances.  Once again though, the best instability will
remain out of Upper Michigan, but a few strong thunderstorms cannot
be ruled out during the afternoon and evening hours with fropa of
cold front.  In the wake of the front though, wnw winds will become
strong with gusts up to 25 to 30 kts.

Further out, brief ridging will bring a break from the active
pattern by Thursday night, continuing into the weekend.  After a
slightly cooler day Friday with highs in the 60s/70s, the warming
trend will commence again for the second half of the extended period
as highs reach the 80s again by Sunday and some of the warmest
temperatures of the season by Monday with models hinting at upper
80s.  A break down in that upper ridge, though, will be indicative
of thunderstorm activity once again by late Saturday with additional
chances through the end of the extended period with multiple waves.

&&

.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 553 AM EDT Tue Jun 11 2024

Winds mainly 20kts and lower will persist across Lake Superior
through tonight.  But, as the high pressure is replaced by a series
of disturbances, an uptick in southerly winds of 20 to 25 knots can
be expected by Wednesday afternoon along with the potential for
strong to severe thunderstorms through the evening hours of
Wednesday.  Southwesterly winds will continue at 20 to 25 knots with
isolated gusts up to 30 knots through Thursday before finally
relaxing on Friday with the return of high pressure. Additional
shower and thunderstorm chances are expected Thursday, but strong to
severe thunderstorms are not expected.

&&

.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...TDUD
AVIATION...
MARINE...TDUD