549
FXUS63 KAPX 282300
AFDAPX

Area Forecast Discussion
National Weather Service Gaylord MI
700 PM EDT Fri Jun 28 2024

.KEY MESSAGES...

- Marginally severe storm possible Saturday. Primary hazard is
  gusty winds.

- Drying out Saturday night into Sunday; clear and cool Sunday
  night.

- Various chances of showers and storms at times Monday night
  and into later next week.

&&

.SHORT TERM /THROUGH SATURDAY/...
Issued at 343 PM EDT Fri Jun 28 2024

PATTERN SYNOPSIS/FORECAST:

Surface pressure continue to fall over the Upper Midwest...with warm
frontal trough taking on a more defined look in the last few
hours...stretching from southern MN to SW WI. Surface dewpoints
finally starting to creep up early this afternoon amid continued
warm advection and overspreading of some light rain/sprinkles
sneaking out of the mid-cloud deck overhead. Even starting to see
some lower clouds slip in along the Lake MI coast near MBL and
points south. Winds not terribly gusty today, except where clouds
break just enough to allow for some better mixing, particularly
upstream; otherwise, stronger winds aloft struggling to mix to the
surface...though a few spots are managing to gust up toward
20-25kts, so will hold onto the small craft advisories for now.

Warm front to continue to lift northward into the region
tonight...with increasingly humid conditions on tap for the
overnight into Saturday morning. Warm and wet overnight...with
embedded thunder at times; even potential for a round of storms
along/ahead of an initial front expected to slip through during the
morning hours. Some clearing possible behind this...with a second PV
maxima dragging a secondary cold front in during the
afternoon...which certainly has some potential for activity as it
could coincide with peak heating amid a relatively moist environment.

Primary Forecast Concerns:

Isolated/conditional severe storms possible Saturday... Not entirely
out of the question that the morning round along/ahead of the
initial cold front could have some isolated severe activity with it,
noting guidance soundings still suggest 500-1000 j/kg of MUCAPE are
possible above 850mb warm front...though this idea is conditional on
having enough forcing to tap into this, which is slightly unclear.
Assuming this idea does come to fruition...think hail could be a
threat, given signals for elevated nature of the convection...though
the downside is that the freezing levels may be quite high (above
12kft)...unless any updrafts get better organized. Wind may not be
entirely off the table in this case, though, as it could promote
downbursts...but strong inversion could dampen out any downward
momentum transfer...such that we may not know if any wind is making
it to the ground until we get reports.

Front may be somewhat slow-moving Saturday, which could allow for
better destabilization across our SE, esp along and south/east of a
line from APN to MBL. Noting deep-layer shear should be on the
increase with time...certainly a possibility that any storms that
develop could become better organized during the afternoon. Not even
entirely off the table that the secondary trough/cold front could
set off some additional activity further west than currently
anticipated. Think the primary threat with these would be gusty
winds noting a lot of dry air aloft; hail may not be quite as much
of a threat with freezing levels up around 12kft...unless we manage
to get anything much better organized.

&&

.LONG TERM /SATURDAY NIGHT THROUGH FRIDAY/...
Issued at 343 PM EDT Fri Jun 28 2024

Pattern Synopsis / Forecast:

Following the passage of a trough axis (which will help fire storms
Saturday evening / early overnight), a flattening 500mb wave and
associated surface low pressure will continue trekking eastward
through Ontario Saturday night, as stout area of surface high
pressure moves overhead Sunday night into Monday. Troughing over
central Canada will then induce an area of zonal flow across the
region, bringing about a favorable regime for embedded shortwaves to
move into the region on the backside of the surface high. Moisture
return and the presence of these waves will culminate in a period of
returning unsettled weather late Monday night through Wednesday.

Primary Forecast Concerns:

Saturday - Sunday: Pesky lingering moisture and a trough axis
pivoting the parent shortwave will be traversing the region Saturday
evening into the overnight hours. This may lead to prolonging of
shower and thunder activity Saturday evening into early Saturday
night. Expectation is that the majority of this activity wanes in
coverage and intensity as we lose diurnally driven instability, but
still could see a locally stronger to perhaps marginally severe
storm... primary hazard being gusty winds. As such, SPC maintains a
Day 2 Marginal Risk for severe storms (Level 1/5) across  This will
be relatively short-lived as a subsidence inversion builds overhead
later Saturday night, suppressing any lingering shower activity as
the aforementioned surface high pressure moves in. Clouds are set to
erode from west to east through the morning Sunday as what is left
of the low level moisture is scoured from the profile, resulting in
a pleasant day with temperatures in the 60s and 70s, and lows
ranging from near 40 inland to the lower 50s by the big lakes Sunday
night.

Midweek: The transient nature of the surface high will be rather
short lived, with return flow building through the evening hours
Monday, and thus, the initial return of cloud cover as moisture is
quickly drawn back into the Great Lakes. Convectively charged wave
with origins in the central Plains and western Corn Belt will try to
make its way into the upper Great Lakes via increasing low level jet
influences. Expectation is that a decaying batch and/or line of
showers and thunder will move into the region Monday night, and
given that the core of the deeper moisture remains to our west in
Minnesota and western Wisconsin, would be less than surprised to see
the more robust convection hold tour southwest, while the leftovers
of this potential activity struggles its way into the APX footprint.
Aforementioned area of deeper moisture will eventually settle into
our wheelhouse later Tuesday into Wednesday as the core of the
amplified 850mb flow is forced overhead by an intruding trough over
central Canada. Given support aloft via an approaching cold frontal
boundary, additional shower and thunder development may manifest
Tuesday evening into Wednesday as 500mb height impulses build into
the region. As stated by previous forecaster, still a little too
early to be throwing out exact QPF for this period, but could be a
sneaky setup for multiple rounds of convection as 850mb winds run
parallel to the front, basically slowing its south and eastward
advancement to a crawl... could be one to watch if one has holiday
week plans. As is tradition, still plenty of finer details to iron
out between now and then. Looking toward the holiday, moisture will
be slow to exit the region. Couple this with lingering troughing, it
will be possible for some additional nuisance showers to leak into
the Independence Day holiday on the 4th at this juncture.

&&

.AVIATION /00Z TAFS THROUGH 00Z SUNDAY/...
Issued at 700 PM EDT Fri Jun 28 2024

Complex area of low pressure will continue to push eastward into
and thru the Western Great Lakes region tonight into Saturday
morning. Waves of showers and embedded thunderstorms will
continue to develop along and ahead of this system...impacting
all of Northern Michigan thru Saturday. Conditions will drop to
MVFR/IFR as this convection impacts our TAF sites tonight into
Saturday. We may see a brief break in the action Saturday
afternoon...before additional convection fires along and ahead
of an incoming upper level trough axis pivoting thru Northern
Michigan on the back side of the departing surface low. LLWS
will develop late tonight into Saturday morning ahead of the
approaching low pressure system. Surface winds will remain from
the S/SE at 10 to 15 kts this evening...becoming SW late tonight
and then becoming westerly on Saturday in the wake of the low
center.

&&

.APX WATCHES/WARNINGS/ADVISORIES...
MI...None.
MARINE...Small Craft Advisory until 2 AM EDT Saturday for LHZ346>349.
     Small Craft Advisory until 8 AM EDT Saturday for LMZ323-341-
     342-344>346.
     Small Craft Advisory until midnight EDT tonight for LSZ321.

&&

$$

SHORT TERM...FEF
LONG TERM...HAD
AVIATION...MLR