730
FXUS63 KMQT 112335
AFDMQT

Area Forecast Discussion
National Weather Service Marquette MI
735 PM EDT Tue Jun 11 2024

.KEY MESSAGES...

- Two rounds of showers move through Upper Michigan this
 afternoon and late this evening.

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

- Gusty winds expected Thursday along with lingering showers
  and thunderstorms.

- Dry Friday and early Saturday before the return of showers
  and thunderstorms later in the weekend.

- Warmer than normal temperatures frequent the forecast, with
  some areas approaching 90 for highs by next week.

&&

.UPDATE...
Issued at 734 PM EDT Tue Jun 11 2024

Stray light showers continue to move through the central and eastern
UP this evening, with mainly trace accumulations expected. Skies are
already clearing out across the western UP, and this trend should
continue eastward the rest of the night. Still, will not rule out
some additional shower activity later tonight with another boundary
moving through the Arrowhead of MN already. That said, guidance is
keeping this next batch of spotty shower activity mostly out over
Superior.

&&

.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 /WEDNESDAY THROUGH TUESDAY/...
Issued at 421 PM EDT Tue Jun 11 2024

The active weather pattern across the CONUS continues through the
long-term forecast. The main features of note at 500mb are a trough
over southern Saskatchewan and a deep cutoff low off the coast of
the Baja California, which will be the cause of active weather
Wednesday night and over the weekend. Despite high pressures that
generally follow both troughing features, the overall weather
pattern through the long term is wetter than normal and warmer than
normal, with some of the hottest temperatures of the year thus far
forecast for Monday.

Beginning Wednesday, as 500mb troughing still remains over the
southern portions of the Canadian Prairie, a 110+kt jet streak at
250mb will move over ND and into MN. With mainly southwesterly flow,
temperatures look to climb into the upper 70s and low 80s in the
afternoon over the UP. Some cu development is expected late in the
afternoon as not much capping is expected, through with synoptic
lift far to the west and dry air at the surface, storms will
struggle to initiate over the UP in the afternoon. A few of the CAMs
do show some isolated high-base thunderstorms kicking off in the
afternoon, but the primary threat for severe weather will come in
the form of storms that fire off upstream in the MN Arrowhead. CAMs
vary significantly on timing and intensity, but most show some
showers crossing Lake Superior from the WNW and arriving over the
western shores of the UP sometime in the 00Z-06Z timeframe.
Northwesterly storms do tend to overperform over the UP
climatologically, and these storms will have some decent shear to
maintain themselves with as 0-6km shear values are around 50 kt
Wednesday evening with 200+ 0-3km SRH. However, by the time the
storms arrive, the MUCAPE will have diminished to 500 j/kg or below,
so the intensity of the storms may struggle to reach severe
criteria. Lots of variables still in play, but a few strong to
severe storms are still expected Wednesday evening as a result.

Once the showers move over the east half Thursday, winds veer
westerly and northwesterly and 850mb cold advection will allow for
some gusty winds to mix down to the surface. EFI shift of tails does
indicate an unusually gusty day for Thursday, and the Euro ensemble
gusts show potential for up to 35+ mph over the western, central,
and interior eastern UP. A few lingering thunderstorms will be over
the east, but with CAPE around 500 J/kg, storms will once again
struggle to be particularly strong.

Once showers move out of the UP entirely Thursday evening, dry
weather will be over the UP through at least Saturday morning as
ridging aloft builds in and supports a near-1020mb high pressure
over the Upper Great Lakes. High temperatures slowly climb back into
the upper 70s and lower 80s. RHs look to fall into the 40s and 30s,
but with very light winds, weather should be benign to end the work
week and begin the weekend.

Meanwhile, the deep cutoff low over the Pacific will deamplify and
shift northeast through the Rockies. The GEFS shows a low pressure
will develop in the Canadian Prairie, with the GEFS suggesting a
central pressure potentially below 990mb into the weekend. With high
pressure shifting to the east, predominantly southerly low level
flow will allow Gulf moisture to surge north, as shown in the NAEFS
vapor transport being at the 90th percentile of climatology. As the
weakening trough approaches the Upper Great Lakes and the cold front
of the Canadian Low approaches, multiple lifting mechanisms for
showers and thunderstorms will be present for the weekend. As the
pattern is complex, details on the strength and timing of storms is
tough to narrow down, so look for future forecast packages to gain
clarity there, but with the available moisture to work with,
ensembles do show about a 20% chance of daily precip totals to
exceed an inch by Sunday, so some downpours could ruin some weekend
outdoor plans.

The gradual warmup continues into next week, with high 80s in the
forecast for Monday, with widespread low to mid 90s in the 75th to
90th NBM percentiles. PoPs remain in the rest of the long term
forecast as ensembles show a continued chaotic pattern through
mid- June. Overall, the CPC outlooks the 8-14 day period as
being more likely to be warmer than normal and wetter than
normal.

&&

.AVIATION /00Z TAFS THROUGH 00Z THURSDAY/...
Issued at 734 PM EDT Tue Jun 11 2024

VFR conditions will prevail at all terminals for the remainder of
the TAF period. An occluded front is steadily passing through the
central UP where some lingering showers will pass by SAW around 00z,
however clearing skies are expected the rest of the night. South-
southwest winds will remain light but begin to uptick tomorrow
afternoon, particularly in the west near IWD. Showers and
thunderstorms are possible tomorrow evening near IWD and CMX ,
however, timing is still a bit uncertain and have left any mention
in the TAFs for now.

&&

.MARINE...
Issued at 421 PM EDT Tue Jun 11 2024

Winds mainly 20 kts and lower will persist across Lake Superior
into the late evening hours. However, accompanying chances of
rain showers tonight in the east-central portions of Lake
Superior are chances of southerly wind gusts in the 20-25 kt
range. Wednesday, multiple chances of showers and thunderstorms
are possible over the lake in the afternoon and evening hours.
The strongest storms are expected to be over the western half of
the lake late Wednesday as storms come off of the MN Arrowhead
and reach the western UP. Behind a cold front driving through
Thursday, cold advection will drive gusty winds aloft to the
surface, with westerly to northwesterly wind gusts of around 25
knots expected on Thursday with a 10% chance of a few gale force
gusts. High pressure building over the Upper Great Lakes into
the weekend will keep wind gusts below 20 kt Friday through
Sunday morning, when a cold front will bring a return of
thunderstorm chances.

&&

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

&&

$$

UPDATE...LC
SHORT TERM...JTP
LONG TERM...GS
AVIATION...BW
MARINE...GS