015
FXUS63 KAPX 171801
AFDAPX

Area Forecast Discussion
National Weather Service Gaylord MI
201 PM EDT Sun Aug 17 2025

.KEY MESSAGES...

- Dry and a bit cool tonight.

- Shower and thunderstorm chances return Monday night into Tuesday

- Mainly dry with seasonable temperatures through the remainder
  of the work week.

&&

.SHORT TERM /THROUGH TONIGHT/...
Issued at 159 PM EDT Sun Aug 17 2025

Definitely some changes taking place out there today...courtesy of
Canada originated high pressure building south into the area. This
has sent active baroclinic axis well to our south and west, with
cool northeast flow and increasing drying through the vertical
spreading overhead. Early morning stratus is finally starting to
succumbed to this aggressive drying, with increasing thinning of the
overcast. Despite this increasing sun, that direct northeast flow
out of Canada has kept temperatures largely in the 60s and
70s...with the warmest readings found in favored downslope areas
near and south of Grand Traverse Bay.

High pressure will slowly move off to the east...replaced by its
upper level parent tonight into at least the first half of Monday.
Low amplitude shortwave still slated to cross the area Monday night
and Tuesday...eventually bringing the next chances for rain along
with it.

Primary Forecast Concerns:

Limited, with primary focus on temperature and cloud trends. Late
Monday rain chances will also need to be addressed.

Details:

Time to open up those windows tonight as clear skies and overhead
Canadian airmass allows temperatures to drop into the upper 40s to
middle 50s...with even some of our traditional colder ice-box
locations perhaps making a run into the middle 40s. Refreshing
indeed after our warm and muggy weather the last few days.

Mainly sunny skies to start Monday will give way to some increasing
high and mid level clouds as upper level moisture kicks in ahead of
that approaching shortwave trough mentioned earlier. May see some
afternoon light showers impact eastern upper as well as coastal
counties of northwest lower Michigan. However...departing airmass is
a dry one and better forcing will remain detached well upstream...
suggesting the more aggressive rain-producing guidance is a touch
too fast. Could easily see any rain holding off until Monday night.
A bit milder on Monday...but still comfortable...with highs in the
70s to middle 80s. Again, expect those warmer readings to center in
favored downslope areas near and south of Grand Traverse Bay.

&&

.LONG TERM /MONDAY THROUGH SATURDAY/...
Issued at 159 PM EDT Sun Aug 17 2025

Pattern Synopsis/Forecast:

Still expecting shortwave trough to work slowly east across the
area Monday night and Tuesday...drumming up shower chances as it
does so. Growing support for slow pattern retrogression heading
further out into the extended...eventually placing northern Michigan
in more direct northwest flow aloft....especially by next weekend.

Primary Forecast Concerns:

Main focus in the long term is addressing rain potential Monday
night into Tuesday. Secondary focus centered on temperature trends
through the period.

Details:

Still looking at some decent rain chances working into the area
Monday night and Tuesday with increased forcing and deeper moisture
advection. As mentioned in this paragraph yesterday...still some
details to work out that will ultimately drive shower/storm
organization and propagation of better rain coverage (most
importantly how does expected upstream convection drive enhanced
convergence corridors and development of enhanced mid level
perturbations). Despite this, do feel most places stand a decent
chance of seeing some much need rain given direct overhead drift of
main mid level wave, decent pre-wave moisture advection, and at
least weak low level jet support (the latter especially Monday
night). While some embedded thunderstorms are possible, any severe
threat will be greatly limited by definite lack of instability and
weak mid level lapse rates. That same set-up does at least support
some locally heavier showers with "skinny" cape through the moisture
rich low and mid levels. Definitely not seeing any evidence of
widespread heavy rain, but wouldn`t be surprised to see some local
areas receive up and over an inch of rain by later Tuesday. Rain
gradually ends during the day Tuesday as best moisture advection and
dynamics slide off to the southeast.

Not a whole lot to talk about for the remainder of the extended.
Trends support deep layer ridging building in Wednesday through
Friday, bringing with it dry conditions and temperatures that will
fall well within the range of normal (although wouldn`t be surprised
to see some rather chilly temperatures back into the 40s both
Wednesday night and Thursday night given expected clear skies and
light/calm winds). Troughing and attendant northwest flow looks to
become established heading into next weekend as pattern
retrogression matures...perhaps bringing a relatively moisture
starved cold front across the region sometime Saturday.

&&

.AVIATION /18Z TAFS THROUGH 18Z MONDAY/...
Issued at 130 PM EDT Sun Aug 17 2025

High confidence in VFR through the period. Winds generally 10kts
with G15-20kts for coastal NE lower terminals (KAPN). Skies of
SCT-BKN at 2.5kft are clearing from north to south and
lifting/scattering (more aggressively over NW lower). Mostly
SKC after 03Z with winds becoming AOB 8kts and VRB. Gusty E/SE
winds build near the end of the period.

&&

.APX WATCHES/WARNINGS/ADVISORIES...
MI...Beach Hazards Statement until 11 PM EDT this evening for
     MIZ018-024-030-036-042.
MARINE...Small Craft Advisory until 11 PM EDT this evening for
     LHZ347>349.

&&

$$

SHORT TERM...MSB
LONG TERM...MSB
AVIATION...ELD