862
FXUS63 KMQT 160804
AFDMQT

Area Forecast Discussion
National Weather Service Marquette MI
404 AM EDT Mon Jun 16 2025

.KEY MESSAGES...

- Strong or severe storms are possible (5-15% chance) this
afternoon/evening across the west half of Upper Michigan. Damaging
winds and large hail are the primary risks.

- Greatest chances for rain and thunderstorms Tuesday night through
Wednesday night are south and east. Scattered showers/storms
possible Thursday across Upper Michigan.

- Near normal temperatures this week trend above normal by late this
coming weekend.

&&

.SHORT TERM /THROUGH TONIGHT/...
Issued at 403 AM EDT Mon Jun 16 2025

Early this morning, KMQT radar returns show light rain shower
activity over western Lake Superior and the Keweenaw Peninsula with
GOES-East Nighttime Microphysics RGB imagery showing a variety of
cloud decks over the UP. METARs show some of these cloud decks as
low as 2kft AGL (such as over the Keweenaw) though out east, cloud
decks to around 5 and 6 kft are observed while high cirrus is also
observed on satellite. RAP 500mb analysis shows these clouds and
showers to be associated with the first in a pair of shortwaves
upstream of the UP. This first shortwave is situated over the MN/WI
line at 07Z and while SPC mesoanalysis shows these showers in a
region of around 250 J/kg of MUCAPE, ample MUCIN is also present and
is helping keep shower coverage and intensity limited this morning.
CAMs generally show scattered to isolated light rain shower
coverage/intensity this morning, so will continue to carry previous
forecast`s 15-30 percent PoPs. This ample cloud coverage is helping
keep this morning`s low temps elevated as well, with 07Z METARs
still showing many locations in the 60s. Not expecting temperatures
to fall much below the mid 50s for most as a result.

00Z HREF suite is unfortunately still spread in regards to the
outlook of thunderstorms for the afternoon time period associated
with the second upstream shortwave. Shortwave that is currently the
cause of ongoing severe thunderstorms in the Dakotas will progress
into Minnesota by the early afternoon hours. Ahead of the
shortwave`s arrival, CAMs do show some isolated convection as HREF
mean SBCAPE grows to 400-800 J/kg and the cap eroding to virtually
nothing. With rather nebulous forcing and sub-100 0-3km SRH that is
just "ok", severe potential with any early afternoon storms is
limited. The main potential for strong to severe convection will
come with the shortwave-forced storms arriving from the west
sometime after 00Z. The timing of the storms` arrival will come as
diurnal instability is waning (though SRH climbs to 125-150),
plus each of the CAMs has a different interpretation of how the
MCS/line of storms evolves, when (if?) it arrives at the UP, and
at what strength. Given the unknown upstream evolution of
storms, the potential for early storm activity to convectively
contaminate the atmosphere, and the timing relative to available
instability, the SPC outlook remains Marginal (1 of 5) for the
interior west with damaging wind and hail being the primary
threats. The most likely solution may be one shared by the HRRR,
NAM Nest, and climatology, that being a strong complex of
storms tracking through northern WI and narrowly avoiding the
UP. However, enough strong storm potential exists (especially
over western Lake Superior) that we can`t take our eye off the
ball just yet. With any luck, the 12Z HREF will finally give the
clarity that the previous two runs have not.

&&

.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
Issued at 230 PM EDT Sun Jun 15 2025

Weak, quasi-zonal flow Monday breaks down with the passage of Monday
night`s shortwave, resulting in weak ridging on both ends of the
country and troughing across the Central Plains Tuesday. Various
shortwaves are noted within this broad area of troughing as it
slowly migrates eastward into and through the Great Lakes region to
round out the end of the coming work week. Upper level ridging
builds into the Central Plains Friday, which stretches into the
Upper Great Lakes Friday night. This ridge looks to gradually result
in an amplified trough/ridge pattern across CONUS through the
weekend. This evolution provides almost daily chances of rain or
thunderstorms for our forecast area this week and coming weekend.

Beginning Tuesday, surface low and associated cold front tied to
Monday evening`s thunderstorm chances will continue to press
northeast and east/southeast respectively, resulting in the slow end
to precip across our forecast area through the day. How slowly looks
dependent on how far the cold front makes it Monday night. A broad
look at various CAMs suggests the front should make it into the west
by early Tuesday morning, then exit to our east by early evening.
Precip should follow this same pattern, with precip ending in the
west by early afternoon and the east by early evening. Instability
ahead of the front across the central and eastern third of the
forecast area may be enough for some thunderstorms, but severe
weather is not expected. Highs across the region span the 70s and
low 80s, with the coolest conditions expected near Lake Superior.
Dry conditions follow Tuesday night for most, although a stray
shower or two can`t be completely ruled out, mainly central and
east. Overnight lows dip into the 50s to low 60s south-central.

While the cold front presses eastward through the Great Lakes and
midwest thereafter, multiple shortwaves within the eastward
migrating trough will help to support various waves of precip along
the boundary through Thursday night. For us, the best chances for
showers or thunderstorms associated with these features will be the
central and eastern portions of the forecast area. Similarly to
Tuesday, severe weather isn`t expected. Thursday afternoon and
evening, daytime instability along with the last wave within the
trough looks to swing through the Great Lakes. This may support more
widespread showers and thunderstorms before conditions diminish with
the setting sun. Daytime highs are expected to climb mostly into the
70s or low 80s while overnight lows settle into the high 40s to 50s.

Friday and into the weekend, ridging presses into our forecast area.
Guidance suggests another wave of showers/storms Friday
night/Saturday. On Sunday, board area of low pressure across the
Northern Plains may result in a warm front lifting through the
region and widespread mid to upper 80s for daytime temperatures.

&&

.AVIATION /06Z TAFS THROUGH 06Z TUESDAY/...
Issued at 130 AM EDT Mon Jun 16 2025

Low stratus has been able to spread across the UP earlier than
previously expected; though satellite shows some breaks in the cloud
cover, this should keep primarily MVFR ceilings in through the rest
of the night and into Monday morning. Improvement to VFR is expected
into the afternoon; however, chances for scattered thunderstorms
return Monday afternoon and evening ahead of an approaching cold
front. Thunderstorms become more likely at IWD and CMX from around
00-06Z, then at SAW after 06Z as the front moves through.

&&

.MARINE...
Issued at 320 PM EDT Sun Jun 15 2025

Light northerly winds of 15 kts or less this afternoon veer east
across the lake this evening then south over the east half of the
lake for Monday. Southerly winds Monday afternoon and evening
increase to around 20 kts ahead of a passing cold front into
Tuesday. This brings potential for some thunderstorms as early as
Monday afternoon, but best shot for storms holds off until Monday
night. There is a marginal risk for severe wind gusts to 34 kts and
hail up to 1" over the far western waters (5% chance) Monday
evening/night. In the wake of showers and storms Monday and Monday
night, some fog development is likely with patchy dense fog <1mi
possible over the west half of the lake 40-50% chance.

West winds up to around 20 kts behind the cold front settle below 20
kts Tuesday night, remaining light and variable through Thursday.
The next potential for 20-25 kts winds returns over the weekend.

&&

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

&&

$$

SHORT TERM...GS
LONG TERM...JTP
AVIATION...LC
MARINE...Jablonski