892
FXUS63 KMQT 170933
AFDMQT

Area Forecast Discussion
National Weather Service Marquette MI
533 AM EDT Mon Jun 17 2024

.KEY MESSAGES...

-Possible strong to severe thunderstorms late today/this
 evening. In addition, heavy rainfall will be a threat today
 with the south- central counties possibly receiving 1-2 inches.

- Strong to severe storms possible Tuesday night into Wednesday.

- Very warm to start the work week, then temperatures trend towards
normal from midweek onward.

- Frequent chances for rainfall continue the rest of the week.

&&

.SHORT TERM /THROUGH TONIGHT/...
Issued at 530 AM EDT Mon Jun 17 2024

The cap has just been too much for showers and thunderstorms to
develop tonight with current showers even quickly diminishing as
they enter Upper Michigan. It has, though, been a warm and muggy
night so far with temperatures holding steady in the 60s across much
of the forecast area.

After this lull in activity, the HRRR does become more active from
the west/southwest after Mon 12Z as a cool front drops into the
area.  It will be tough for this first round of thunderstorms to
become strong to severe, however, with cloud cover still lingering
over the area.  Better chances will come later today as a surface
low continues its track from northeast Nebraska toward southeast
North Dakota.  Meanwhile, its associated warm front will push
northward across the Upper Midwest providing an area for additional
convective development along and north of it through the peak
heating of the day.  The best chances for any warm sector storms
will remain behind the front, concentrated over southern MN/central
WI.  Nonetheless, sufficient bulk shear could be enough to support
isolated strong to severe thunderstorms crossing into the UP
late today into tonight. The higher threat tonight, though,
could be the heavy rainfall with western and central portions of
the forecast area under a Slight Risk for excessive rainfall
and WPC guidance pinpointing 1-2 inches across the south-
central counties.

As far as temperatures, trended a bit higher across the far southern
counties due to the surge of WAA, putting that quadrant in the low
80s. Elsewhere across the UP, widespread mid to upper 70s are
expected except across the far west and along the spine of the
Keweenaw. Those areas will trend more toward low 70s. Tonight,
another warm and muggy night is expected as overnight lows hold
steady in the 60s across the interior with 50s near the
lakeshores.


&&

.LONG TERM /TUESDAY THROUGH SUNDAY/...
Issued at 418 AM EDT Mon Jun 17 2024

The active weather pattern doesn`t look like it will relent over the
rest of this week as troughing deepens over the western U.S. and
ridging amplifies over the Eastern Seaboard early this week. This
keeps us on tap for very warm and moist conditions Monday through
Tuesday, before the troughing pattern moves east and brings cooler
temperatures across our area Wednesday into Thursday; be careful if
working outside Tuesday, as the hot and humid weather could cause
heat exhaustion and heat stroke! Meanwhile, expect showers and
thunderstorms chances to continue across Upper Michigan throughout
the rest of this week into next weekend, with a few strong to severe
storms being possible Monday and Tuesday night/Wednesday. The severe
weather threat, should any occur, would be hail, winds, and repeated
heavy rainfall causing ponding. Additional details follow below.


The frontal boundary lifts north of the area Tuesday, and should
stall out across northern Lake Superior and northern MN. Skies turn
sunny, then expect muggy and even warmer weather Tuesday as we sit
directly underneath the warm sector of a low lifting through the
Lake Winnipeg area. A tight pressure gradient and a 30-40kt LLJ over
the area all point to a potential for a breezy day (will also note
the EFI continuing to highlighting unusually strong winds for Tuesday).
However, with a low-level cap in place, it may be difficult to get
the winds to gust much more than 30 mph, save for the downslope
areas near Lake Superior where mixing could be locally enhanced.
Expect temperatures to get into the high 80s to low 90s during the
afternoon hours, with dewpoints reaching up into the low 70s. This
will cause the heat index to get into the 90s across much of the
area, with a spot or two possibly flirting with the 100 degree mark.
Breezy conditions may help to keep things from feeling so
oppressive, but be mindful of the heat and take precautions
regardless. Stay hydrated!

Moving into Tuesday night, the aforementioned low near Lake Winnipeg
will continue to move through Ontario while weakening, then the cold
front off to our west slowly swings through overnight into
Wednesday. Showers and storms begin to move back into the western UP
as early as Tuesday evening along the front, which would be
favorable timing for strong to severe convection. MUCAPE across the
western UP could exceed 1000 J/kg and 0-6 km bulk shears approach 40
to 50 knots. Our main threat would be hail, with damaging wind a
secondary concern. In addition, expect heavy rainfall, with
ensembles showing PWATs near the max of climatology/around 2 inches!
With storms possibly training ahead of the frontal boundary, ponding
of water in poor drainage would be a concern. However, as episodes
of rain in the preceding days have chipped away at hourly flash
flood guidance, some flash flooding is not out of the question
(around 5% chance) in smaller streams and even in somewhat better-
draining areas. The central and eastern UP may miss out on severe
convection Tuesday night as we`ll have long since run out of
daylight by the time the front moves in.

Meanwhile, nighttime won`t do much to alleviate heat concerns as
temperatures only fall back as far as the mid/upper 60s for a large
portion of the area.

Wednesday, the front finally begins to settle just to our south.
Weak waves rippling through will provide some additional lift to
keep chances for convection to fire along the boundary Wednesday
through Friday. Will note that PoPs are concentrated mainly across
the southern half of the UP given the potential for weak high
pressure over Ontario to further suppress the frontal boundary
southward. Going into next weekend, a low pressure lifting off of
the Colorado Rockies and an upper level Clipper low look to phase
with each other over the Upper Midwest. This will bring additional
showers and thunderstorms across our area via warm frontogenesis
through at least the first half of next weekend, then the cold front
moves through late in the weekend with lingering PoPs. Ensembles
continue to favor PWATs as high as 2in, well above normal,
highlighting another couple of days worth monitoring for the heavy
rainfall potential.

&&

.AVIATION /06Z TAFS THROUGH 06Z TUESDAY/...
Issued at 122 AM EDT Mon Jun 17 2024

Expect maybe some isolated showers across the area tonight with
showers affecting mainly IWD and CMX. The moist conditions could
still lead to MVFR conditions overnight in patchy fog or stratus.
Around round of convection is expected to move in from the west
after sunrise as ceilings will likely go to MVFR during the day on
Monday. Showers will be most prevalent at IWD and SAW with SAW
having the best chance of getting a thunderstorm. A break in the
showers in the afternoon could be followed by more scattered showers
Monday evening. Look for MVFR ceilings to lower to IFR Mon evening
and fog formation possible again.

&&

.MARINE...
Issued at 418 AM EDT Mon Jun 17 2024

Light winds around 5-10kts start off mainly from the west this
morning, but shift over to the east this afternoon. The light winds
continue through tonight before increasing from the south to 20 to
25 knots over the eastern half of the lake Tuesday. In addition,
expect some downsloping winds near the southern shoreline to gust up
to 20 to 30 knots, with a few gale force gusts up to 35 knots
possible (10% chance or lower), particularly in the nearshores from
Marquette to just west of Whitefish Point. The winds fall back down
to 20 knots or less again by early Wednesday morning as the frontal
boundary just west of the area finally begins moving across the
lake. Winds stay light through the rest of the week as weak high
pressure ridging settles over northern Ontario.

Several rounds of showers and storms are expected across the lake
from this afternoon through Wednesday. Some strong to severe storms
are possible during this time, with hail and wind being the main
threats. Areas of fog, dense at times, are possible following rounds
of rainfall.

&&

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

&&

$$

SHORT TERM...TDUD
LONG TERM...LC
AVIATION...Voss
MARINE...LC