117
FXUS63 KMQT 111726
AFDMQT

Area Forecast Discussion
National Weather Service Marquette MI
126 PM 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 TODAY/...
Issued at 126 PM EDT Tue Jun 11 2024

A line of showers has progressed west to east through Minnesota and
into western Lake Superior today. Dry air, apparent on GOES Water
Vapor imagery, has resulted in a gradual diminishing trend to this
line as its moved closer. Cloud cover has also expanded across
western and central Upper Michigan, resulting in highs only in the
low 60s interior west. Elsewhere, enough sunshine was observed to
allow warming into the mid-upper 60s, except near Lake Michigan,
which has been moderated by southerly flow off the bay and lake.
These spots have barely climbed into the low 60s.

As we progress through the remainder of the afternoon and overnight
tonight, a weakening occluded front will continue pressing eastward,
spreading cloud cover and light rain east across Upper Michigan.
Only light accumulations are expected given the antecedent dry air. A
rumble of thunder or two can`t be ruled out. Further upstream in
northwestern Minnesota, increasing instability this afternoon may
result in showers and thunderstorms developing and pressing
east/southeast ahead of another shortwave rotating around a mid-
level low in Manitoba. This may support another round of brief
showers, perhaps a thunderstorm, late this evening in the
Keweenaw/west and after midnight in the east before clearing skies
spread overhead. Significant additional heating isn`t expected
today, so expect highs mostly in the 60s to near 70F in some spots.
Overnight lows should dip into the 50s, maybe high 40s in the
interior west if we`re able to clear out earlier then expected.

&&

.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 /18Z TAFS THROUGH 18Z WEDNESDAY/...
Issued at 126 PM EDT Tue Jun 11 2024

Cloud bases will gradually lower this afternoon as a weakening
occluded front brings showers west to east through the evening
hours. Some thunderstorms will be possible, mainly at KIWD, but
confidence is low (<25%). MVFR ceilings may be achieved as well,
particularly at KIWD this afternoon and KCMX this evening. Expect
clearing skies overnight. Winds will prevail out of the south then
southwest tonight. Guidance is still keen gusty conditions at KIWD
this afternoon. However, no gusts have been observed there or
upstream. While still possible, I`ve removed it from this TAF given
the probability appears to be low (<25%). Mist/fog may develop
overnight at KCMX and KSAW before lifting after sunrise.

&&

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

&&

$$

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