000
FXUS63 KAPX 250709
AFDAPX

Area Forecast Discussion
National Weather Service Gaylord MI
309 AM EDT Sun Sep 25 2022

.NEAR TERM...(Today through Tonight)
Issued at 305 AM EDT Sun Sep 25 2022

...Damp and Cool...

High Impact Weather Potential: Minimal. May see a few non-severe
thunderstorms later today into tonight near and south of Grand
Traverse Bay.

Pattern Synopsis/Forecast:

Classic fall-looking pattern out their early this morning, with deep
(and deepening) troughing centered right across the Great
Lakes...downstream of stout west coast centered ridge axis. Weak
surface reflection tucking right under trough axis...pushing east
into northern Lake Huron. Attendant broad large scale forcing and
plentiful moisture through the vertical kicking off widespread low
clouds and pockets of light showers/drizzle across the Northwoods.
All those clouds have really helped flatline the typical nocturnal
temperature response, with current readings (lower and middle 50s)
just a few degrees cooler than high temperatures observed yesterday.

Troughing will continue to dominate our weather through the
beginning of this week, bringing with it seasonally chilly
temperatures and periodic shower chances...the latter of which will
definitely take on a more lake component with time.

Primary Forecast Concerns/Challenges:

Main focus on shower evolution and temperature trends through
tonight.

Details:

Troughing will only deepen with time today and tonight, with closed
mid/upper level circulation expected to set up shop across the
northeast Great Lakes. Surface low will slowly deepen as it reaches
vicinity southwest Quebec by Monday morning. Broad cyclonic flow on
north side of northern stream jet will encompass the entire Great
Lakes region through tonight. Various mid level perturbations and
passing surface troughs within a deep moist layer will continue to
drum up occasional showers through tonight (and beyond). Should get
an increasingly organized lake component to showers later today and
tonight with development of decent low level lapse rates given
cooling low levels atop Lake Michigan surface water temperatures in
the upper teens Celsius. Northwest flow through the deepening lake-
induced convective layer will target the traditional lake belts of
northwest lower Michgian...especially downwind of Grand Traverse
Bay. Expect showers to become fairly widespread in this area
tonight, with some brief locally heavier rainfall rates expected.
Lift through the ice production layer of the clouds looks just
substantial enough too produce decent charge separation...supporting
at least isolated non-severe thunderstorm potential. Otherwise,
plenty of clouds and cool conditions expected...with highs today
again only topping out in the 50s for most areas. Look for lows
tonight back down into the mid and upper 40s.

&&

.SHORT TERM...(Monday through Tuesday)
Issued at 305 AM EDT Sun Sep 25 2022

...Rain continues...

High Impact Weather Potential: Minimal for now. Monitoring low end
chance of heavy/steady rain potential.

Synopsis/Forecast: Broad longwave troughing dominates the eastern
half of the CONUS while ridging remains over the west. Heading
through the rest of the weekend into the early workweek energy
digging down through western Ontario only reinforces the troughing
over the Great Lakes...while shortwaves pushing into the Pac NW work
to dampen the western ridging. Lower than normal 500mb heights
remain overhead through Tuesday, with abnormally cool and damp
conditions through mid week.

Details: A stacked low across southeastern Ontario will continue to
drag more cool air over us on gusty northwesterly winds. Plenty of
synoptic moisture will remain across the region (PWAT`s just a
smidge above average at 0.8"). We`ll have some dynamic support from
a wave rotating across the area, as well as surface convergence in
the cyclonic flow regime. This combined with deltaT`s anywhere from
13 to 17C will help the lakes contribute to lake enhanced showers.
Rain totals should be around an inch Monday through Monday night...
with possibly two convergence bands setting up early in the day off
the lakes, one specifically targeting areas around Grand Traverse
Bay. Localized flooding the next couple days isn`t zero, but the
probability isn`t very high, and will simply need to monitored over
the next 24 to 36 hours.

Winds will be quite gusty with the tight pressure gradient,
especially along the shorelines...as momentum could be easily mixed
down in the CAA regime. As with the past couple days, temperatures
won`t rebound very well through the daytime, leading to high`s a
good 5 to 10 degrees below normal.

Monday night into Tuesday we`ll experience much of the same, with
some dry time possible along and south of M-55 before better
moisture rotates down from the north midday Tuesday. For Tuesday
rain totals look to be less than half an inch.

With the cold pocket over us and impressive lake cloud depths some
waterspouts are possible on both days.

&&

.LONG TERM...(Tuesday night through Saturday)
Issued at 305 AM EDT Sun Sep 25 2022

...Turning colder with more frost/freeze before late week warm up...

High Impact Weather Potential: Widespread frost Wed night.

A brisk Wednesday will turn into a downright frigid night with a
surface high directly overhead. Kept close to inherited Wed night
lows (besides tweaking higher terrain valleys a tad colder) as the
Extreme Forecast Index (EFI) shows a good chance of abnormally cold
temperatures...possibly meeting or maybe even breaking records, with
record lows in the mid 20`s. Troughing finally moves out of the
Great Lakes Thursday followed by briefly zonal flow late week into
the weekend. We get into some return flow with milder air bumping up
temperatures closer to normal late week.

Meanwhile Ian will move through the Gulf midweek, bringing a surge
of moisture for the east coast late week.

&&

.AVIATION...(For the 06Z TAFS through 06Z Sunday night)
Issued at 1149 PM EDT Sat Sep 24 2022

Grungy thru the forecast.

Lots of moisture out there, as an upper level low crosses upper
MI. Areas of showers and drizzle will persist thru the forecast,
as will low cigs. Cigs will tend to lower during the night, then
rise up again a bit on Sunday. PLN/CIU/APN will see IFR cigs at
times late tonight, while MBL/TVC will drop to low-end MVFR.

Light se winds tonight. Nw winds become a bit breezy on Sunday.

&&

.MARINE...
Issued at 305 AM EDT Sun Sep 25 2022

Northwest winds will gradually be on the increase today and tonight
as slowly deepening low pressure pushes east of the region. Expect
widespread small craft advisory conditions to first develop tonight
across northern Lake Michigan...spreading across the remainder of
our nearshore waters on Monday. May even see a few gale force gusts
develop on Monday across portions of northern Lake Michigan. Winds
will gradually subside Monday night into Tuesday. Definitely a wet
period of weather the next several days, with periods of showers
right through Tuesday. Will need to also be on the lookout for
waterspouts and isolated thunderstorm potential.

&&

.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...NONE.
LM...Small Craft Advisory from 8 PM this evening to 8 AM EDT Monday
     for LMZ344>346.
LS...NONE.
&&

$$

NEAR TERM...MSB
SHORT TERM...STJ
LONG TERM...STJ
AVIATION...JZ
MARINE...MSB

NWS APX Office Area Forecast Discussion