240
FXUS63 KAPX 250349
AFDAPX

Area Forecast Discussion
National Weather Service Gaylord MI
1149 PM EDT Mon Jun 24 2024

.KEY MESSAGES...

- Watching the potential for some strong thunderstorms later
  tonight into Tuesday.

- Additional chances of active weather return this weekend.

&&

.UPDATE...
Issued at 938 PM EDT Mon Jun 24 2024

Quiet wx here at the moment, as surface high pressure pushes
east across Lake Erie and Georgian Bay. But in the wake of this
ridge, warm advection is getting underway. A mid-cloud band and
some weak radar returns are noted near ISQ-Munising. Spotty deep
convection is over southern WI, and in far northern MN. We await
additional convective development between these two areas, with
impressive instability/shear but with a cap that is still
hindering initiation. Most CAMs are insistent on deep convection
triggering in parts of central MN into western WI, then growing
upscale into an MCS that targets Lake MI and lower MI. This
occurs as warm advection upstream further strengthens, enough so
to overcome the cap and sustain convection.

CAM guidance remains wet for us very late tonight into Tue
morning, and the going forecast has been tweaked but still
reflects that. A particularly popular solution is to bring a
warm advection wing of SHRA/TSRA into western areas after 2 am,
followed closely by a bow echo heading into nw lower MI after 4
am. The latter should be in a weakening state in this scenario;
we will not be as unstable as further west. But we are
eventually on the nose of the low-level jet by about 09Z/5am,
which supports MuCape values somewhat in excess of 1k j/kg
working into our far sw areas.

The above scenario poses a severe wind threat to our area, in
particular in nw lower MI. SPC was enough of a believer to
expand the Day 1 Slight risk into more of nw lower MI, including
TVC and CAD. This is all dependent on convection developing, and
fast, upstream. Though this forecast absolutely has bust
potential, the threat of svr wx (damaging winds in particular)
overnight has increased.

&&

.SHORT TERM /THROUGH TUESDAY/...
Issued at 307 PM EDT Mon Jun 24 2024

Pattern Synopsis/Pattern Forecast:

Mid/upper level ridge in the process of building east across the
area early this afternoon as its surface reflection pushes off into
the northern Ohio Valley. Attendant dry air and deep layer
subsidence resulting in one downright pleasant early summer day
across the Northwoods, with sun-filled skies and temperatures
recovering up to near normal levels in the 70s and lower 80s.

Rather rapid changes set to take place overnight into Tuesday as
shortwave trough, currently racing east across the southern lands of
Canada and northern Montana, pushes into the western Great Lakes by
morning. Surge of pre-system warm, moist advection and eventual
passage of cold front set to bring a round of showers and
thunderstorms into the region later tonight.

Primary Forecast Concerns/Challenges:

Late night into Tuesday shower/storm evolution and severe weather
potential.

Details:

Pleasant evening expected with just some increasing clouds with
time. Unfortunately, uncertainty ramps up significantly as we head
into the overnight. Strong moisture advection on nose of organizing
and intensifying low level jet and attendant rapidly increasing
upstream instability axis will drive the organization and
intensification of showers and thunderstorms to our west. What
happens thereafter remains the unanswered question. If convective
allowing guidance`s placement/evolution of low level jet and folding
instability gradient is realized, then shower/storm evolution should
trend southeast, with most organized and intense activity sliding
into southwest lower Michigan later tonight...leaving more "generic"
and more scattered activity to impact our area. Pattern recognition
of these type of systems strongly supports this idea. However, if
forced convergence on nose of low level jet is displaced just a bit
further north, then upstream more organized and intense activity has
a much better chance to impact at least parts of our area later
tonight into early Tuesday. Will definitely need to monitor, as
increasing deep layer shear through the depth of the convective
layer would support a least a low end severe wind threat...as well
as some marginal severe size hail. Latest SPC convective outlook
continues to highlight this potential, placing nearly all of
northern Michigan into a marginal risk for severe weather.

What happens tonight/early Tuesday morning will significantly dictate
what transpires later Tuesday. Actual cold front set to cut west to
east across our area during the morning and early afternoon, with
that timing at least theoretically supporting the potential for
additional destabilization...especially across northeast lower
Michigan (if skies can at least partially clear). However, primary
instability axis will remain well south of us, and any pre-frontal
convergence axis (from morning showers/storms) may drive best
convergence south and east of our area before actual front arrives.
Very possible late Tuesday morning and afternoon are completely
devoid of any activity, with showers and storms remaining east and
south of our area. Again...if storms can develop, isolated severe
potential will continue given brisk wind fields through the
vertical.

&&

.LONG TERM /TUESDAY NIGHT THROUGH MONDAY/...
Issued at 307 PM EDT Mon Jun 24 2024

PATTERN SYNOPSIS/FORECAST:

Longwave troughing will continue chances of active weather before a
ridge of high pressure builds overhead promoting quieter weather by
mid-week. Low pressure tracks along the northern U.S and Canadian
border, and eventually to Lake Superior for Friday/Saturday,
bringing back the next chances for showers/ thunderstorms.
Temperatures will increase throughout the week then decrease for the
weekend as active weather is expected to return.

PRIMARY FORECAST CONCERNS:

- Precipitation Chances: A shortwave trough will slide across the
Great Lakes Region Wednesday bringing increasing cloud cover through
the day. Some guidance hints that some light showers could be
possible later in the day Wednesday, but confidence is low.
Attention then turns to a longwave trough and its associated low
pressure will track towards the Great Lakes Region Friday/Saturday
bringing active weather back to the forecast area. It`s still too
early to message specific impacts, but guidance suggests that it`s
likely active weather will return for this weekend- Stay tuned!

&&

.AVIATION /06Z TAFS THROUGH 06Z WEDNESDAY/...
Issued at 1148 PM EDT Mon Jun 24 2024

A round of thunderstorms is expected to impact the area after
09Z, pushing quickly e and se across the area. Brief but
significant restrictions along with gusty winds will be
possible, with the best chance at MBL and TVC. Some lower cigs
will linger for several hours after precip ends, with gradual
improvement on Tuesday.

&&

.APX WATCHES/WARNINGS/ADVISORIES...
MI...None.
MARINE...None.

&&

$$

UPDATE...JZ
SHORT TERM...MSB
LONG TERM...NSC
AVIATION...JZ