730
FXUS63 KAPX 070658
AFDAPX

Area Forecast Discussion
National Weather Service Gaylord MI
258 AM EDT Tue May 7 2024

.KEY MESSAGES...

- Rain showers/thunder this afternoon into tonight.

- Rain/showers Wednesday and again Thursday.

- Patchy frost at times, particularly Thursday night?


&&

.SHORT TERM /THROUGH TONIGHT/...
Issued at 257 AM EDT Tue May 7 2024

Pattern Synopsis/Forecast: Upper-level ridging currently over the
western Great Lakes will steadily push east today in advance of
vertically stacked low pressure pinwheeling across the northern
Plains. As a result, height falls are expected locally through the
day ahead with increased shower/storm chances later this afternoon
into tonight as mid-level energy pinwheels around upstream parent
low pressure aiding to drive an occluded front toward the western
Great Lakes.

Forecast Details:

Another cool start this morning, especially across interior areas.
Lots of sun this morning gradually gives way to more filtered
sunshine through the midday and early afternoon hours as high clouds
gradually increase and thicken from southwest to northeast.
Warm/moist advection on the heels of increasing southeast winds
expected through the day with initial shower chances arriving across
southwest portions of the forecast area between 18-21z. This shower
activity is expected to work northeast over the remainder of the
area through the late afternoon and evening hours. Embedded
thunderstorms possible through the duration this afternoon/evening
with primarily elevated instability progged up to 250-500 J/kg. Not
anticipating a severe weather threat locally given our proximity to
the warm front and associated warm sector, with those severe weather
chances higher downstate into the Ohio Valley.

Most numerous showers expected to shift into eastern upper overnight
with a relative lull across much of northern lower, although
coverage may expand again over the tip of the mitt and northwest
lower for the second half of the night into Wednesday morning.
Generally mild lows in the upper 40s to mid-50s.

&&

.LONG TERM /WEDNESDAY THROUGH MONDAY/...
Issued at 257 AM EDT Tue May 7 2024

PATTERN SYNOPSIS/FORECAST:

Strong northwesterly flow into the back of broad troughing over the
central Plains, with primary upper low focused over SE MT; ridge
continues to build through the Upper Midwest. Strong southerly LLJ
up through the Plains ahead of strong BCZ along perimeter of the
troughing aloft (981mb surface low over western SD, with boundary
stretching down into TX as of 2-3z/07)...where the bulk of the
convective activity has been occurring. Surface warm front at this
same time stretches from Nebraska into the OH Valley...with abundant
moisture (pwats approaching or exceeding 1.5in) south of this. E/SE
flow becoming more evident along and north of this across the Upper
Midwest, though surface high is still near enough to us (loosely
over N. Lake Huron, though made more nebulous with a zonal-ish
stationary boundary across southern Canada) that some land breezes
developing over the Lake Huron coast.

Expecting lobe of energy to swing up into the region today with
attendant warm front and convective activity through tonight. Looks
like the boundary will stall out over northern MI tonight into
Wednesday, as upstream upper low reluctantly meanders eastward
across the northern Plains into the Upper Midwest. Think some
deformation axis rain should hang on across the UP/Straits region
for much of Wednesday, though it may not be entirely quiet across
northern Lower during the day, with some signals for daytime showers
to develop...as the boundary attempts to slowly seep southward
Wednesday evening with a weak niblet passing through Ontario.
Meanwhile...reluctant Plains energy finally ejecting Wednesday night
into Thursday should result in another wave slipping into the OH
Valley. This should keep the threat of a chilly/dreary rain around
Michigan for Thursday, though some uncertainty in the position of
the surface low lends some uncertainty in how far north this
dreariness will end up. A chilly night possible Thursday, especially
if the surface low ends up trending further south of the area. Brief
improvements Friday should be followed quickly by a clipper system
digging into the Upper Midwest for the weekend, keeping things on
the cool and unsettled side. Decreasing certainty in how the pattern
evolves for early next week, though it appears troughing still tries
to settle into the central US somewhere...which could keep the
cooler idea going into the middle of the month.


Primary Forecast Concerns:

Rain/showers Wednesday and again Thursday...
Precip threat Wednesday will be a bit of a two-fold event. Think the
primary focus for more of a stratiform-type/widespread rain will be
across the Yoop/Straits, along and north of the boundary where
deeper moisture should hold on longest (pwats still toward the high
end of climo), amid a potential deformation axis over that region
that could enhance localized forcing. Not expecting a ton of
additional rain after 12z Wednesday, as moisture appears to start
stripping out aloft. Meanwhile...south of the Bridge, and south of
the stalled boundary...have a suspicion we may not be totally done
with shower activity, maybe even a rumble of thunder, particularly
as the boundary attempts to weakly sink southward through the area
during the afternoon, during best diurnal heating...though this idea
is much less clear.

Moisture plume with the next system begins to lift into the region
as early as Wednesday evening from the southwest...though there is
still some uncertainty in timing/position of how far north this
gets...depending on how sharp the track of the shortwave trough ends
up as some northern stream energy wraps up into it Thursday to help
kick it out. Sharper, more well-defined system would try to wrap
things further north, affecting more of our CWA...keeping things
cooler and drearier overall. Less well-defined/more zonal idea would
be a little more progressive/a little further south, and could
result in less dreariness...as we`d have a better shot at being
north of the sharp cutoff with the precip shield. Either way...this
should be a bit more of a standard synoptic rain for us on the north
side of the surface system...with some potential mesoscale banding
within the broader rain plume that could bring locally higher
totals.

Patchy frost at times, particularly Thursday night?...think patchy
frost could be possible at least Thursday night, with less certainty
through the remainder of the week/weekend. If the system Thursday
does end up further south, with a greater chance for high pressure
settling in Thursday night, will have to keep an eye out for low
temps to fall into the mid 30s again, similar to earlier this week.
However...it could be a bit of a catch-22, as I do have to wonder if
the expected rain will keep the boundary layer a little more moist
than what we saw earlier this week, which could keep things from
bottoming out quite as much as it otherwise could. Still think we
will be fairly seasonable on temps even so, with highs around 60 and
lows in the upper 30s to around 40...which, compared to recently,
will feel a little on the cool side.


&&

.AVIATION /00Z TAFS THROUGH 00Z WEDNESDAY/...
Issued at 1036 PM EDT Mon May 6 2024

VFR conditions under just some passing high clouds through at
least the first half of today. Expect lowering cigs and
increasing shower chances to spread in from west to east later
today into this evening, eventually bringing MVFR conditions to
the taf locations. Light winds expected to become a bit gusty
out of the southeast today.

&&

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

&&

$$

SHORT TERM...MJG
LONG TERM...FEF
AVIATION...MSB