154
FXUS63 KAPX 151919
AFDAPX

Area Forecast Discussion
National Weather Service Gaylord MI
319 PM EDT Mon Jul 15 2024

.KEY MESSAGES...

- Front passage late this evening will bring chances for showers
  and thunderstorms into tonight

- Isolated/scattered showers and storms Tuesday night and
  Wednesday with cooler weather through the end of the week.

&&

.SHORT TERM /THROUGH TUESDAY/...
Issued at 317 PM EDT Mon Jul 15 2024

Pattern Synopsis and Forecast: The center of the upper level ridge
that has been dominating the western US for some time now is
shifting slightly southward. An upper closed low over over Manitoba
CA is starting to dip south towards the northern Plains. Generally
west winds aloft over the Great Lakes region will persist, however a
cold front will make its way over the state later this evening and
into tonight ahead of the larger system. The airmass ahead of the
boundary will be warm and moist, leading to high instability over
our neighbors to the east. Current satellite and radar depict
convection starting to fire along the boundary in MN. It will likely
mature into an MCS as it moves southeast. Northern MI will likely be
too far north for the MCS to track through, however the surface low
will be to our north meaning a cold front will still move through
late this evening. Isolated to scattered showers and thunderstorms
will likely form along the boundary as it moves through (8PM on the
western shores and gone by 6 AM for most areas). Most storms will be
capable of producing heavy rain, small hail, and gusty winds up to
45 mph. A few storms could be capable of producing severe wind gusts
within their outflows and/or down drafts. Isolated storm chances
linger over northern lower through early Tuesday morning. Skies
should clear by Tuesday midday, with little chances for rain or
storms. Temperatuers will be cooler Tuesday with drier air settling
in. Breezy northwest winds Tuesday afternoon.


Primary Forecast Concerns/Key Messages: Decent uncertainty still
exists for how late evening will look, however guidance seems to be
keying in on a solution. CAMs generally show scattered storms along
the boundary as it moves through starting around 8 PM tonight.
Instability (even MUCAPE) will diminish later this evening as the
front moves through, which is the possible wrench. This drop in
instability is believable due to drier mid level air moving over
(proof seen in surface few points mixing down to the mid 60s for
some sites this afternoon). Around 30 to 40kts of 0-6km shear exists
and will help keep storms organized and sustained as they move
across the penisula. All of this points to a likely scenario of
isolated to scattered storms along the boundary as it moves through
after 8 PM tonight. Most storms will produce heavy rain, wind gusts
up to 45 mph, and small hail. A storm or two will have the chance to
strengthen and could produce severe wind gusts. Model soundings show
around 15kts of LL shear, and paired with higher LCL heights(~4-5
kft) due to slightly drier air, very little to no chance for
tornados exist with tonights storms.

Wind gusts of even 40 mph can take down trees when paired with heavy
rains. Make sure to keep up with the latest forecasts and warnings.

&&

.LONG TERM /TUESDAY NIGHT THROUGH MONDAY/...
Issued at 317 PM EDT Mon Jul 15 2024

Pattern Synopsis:

Amplified troughing sagged across much of south-central Canada and
the north-central CONUS will continue to pivot over the Great Lakes
through the middle of the week. Said troughing looks to depart east
of the region Thursday into Friday as ridging temporarily folds
overhead. Subsidence aloft provided at the ridge/trough inflection
point is expected to build surface high pressure across the Great
Lakes for the second half of the work week into the beginning of the
upcoming weekend.

Forecast Details:

Showers/storms Tuesday night into Wednesday, cooler ahead -- As
height falls overspread the Great Lakes Tuesday night, rain chances
will gradually increase into Wednesday. Forcing aloft combined with
relatively steep lapse rates/meager buoyancy will support isolated
to scattered showers and thunderstorms through Wednesday. More
specific details regarding timing/location of best rain chances will
become more clear as Wednesday draws near. Precip chances will wane
Wednesday night into Thursday as aforementioned high pressure builds
into the region, keeping shower/storm chances low through the
remainder of the period. Meanwhile, northwest low-level flow will
advect cooler, drier air into the region through the middle of the
week. This looks to drop high temperatures into the upper 60s and
70s through Thursday, which would be around 10-15 degrees cooler
than average for the middle of July. Chilly overnight lows are also
anticipated, likely dipping well into the 40s across interior areas
Thursday night with calm winds and clear skies allowing for
efficient radiational cooling. Temperatures look to warm back up
close to average (upper 70s/low 80s highs, mid 50s/low 60s lows)
heading into this weekend.

&&

.AVIATION /18Z TAFS THROUGH 18Z TUESDAY/...
Issued at 204 PM EDT Mon Jul 15 2024
Currently VFR conditions with skies mostly SKC to FEW080 as CU
continues to form this afternoon. Lk breeze currently over
eastern upper is producing towering CU and ISO TSRA. Chances for
ISO-SCT VCTS this afternoon along Lk breezy is highest near
eastern upper and northeast lower terminals from 19Z through
00Z. After 00Z a FROPA will bring chances for TSRA/VCTS to most
terminals moving from NW to SE which leads to chances for
MVFR/IFR cigs and vis. ISO VCSH chances will linger for most
terminals through 10Z. Patchy BR/FG could form from 10Z through
13Z for some terminals impacted by RA. Conditions will improve
to VFR for most terminals by 16Z.

&&

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

&&

$$

SHORT TERM...ELD
LONG TERM...DJC
AVIATION...ELD