523
FXUS63 KAPX 151739
AFDAPX

Area Forecast Discussion
National Weather Service Gaylord MI
139 PM EDT Thu Aug 15 2024

.KEY MESSAGES...

- Shower and thunderstorm chances increase this afternoon and
  tonight.

- Unsettled wx continues thru this weekend.

&&

.UPDATE...
Issued at 942 AM EDT Thu Aug 15 2024

High pressure over central PA will continue to move eastward. An
occluded low is near GFK. Southerly return flow is underway,
though actual moistening is in its very early stages. (12Z APX
observed Pwat 0.78", vs 0.72" 24 hours ago.) Cirrus is expanding
and thickening over northern MI, but actual precip is only
slowly advancing across central/se WI and southern Lake MI.
(Rain has recently begun at MKE.)

Cloud cover will continue to increase and thicken. Initial precip
chances will eventually push into nw lower MI (MBL area in
particular), toward and after 4pm. Best chance for any showers
thru 00Z/8pm will remain west of a TVC-Lake City line (though
better chances for precip will be after that).

Max temps will be warmest out ahead of the thicker cloud cover.
Highs range from near 80f near MBL/CAD...to the mid 80s for
ANJ/PLN/APN.

&&

.SHORT TERM /THROUGH TONIGHT/...
Issued at 247 AM EDT Thu Aug 15 2024

     Increasing chances of showers and storms this afternoon and
tonight...

High Impact Weather Potential...Chances of non-severe thunderstorms
will steadily increase this afternoon into tonight.

Strong high pressure center continues to slowly push eastward away
from Michigan and into the NW US early this morning. Skies remain
clear across our entire CWA attm...but a look upstream at both
observed and model data shows big changes are on the way. Complex
area of low pressure continues to develop to the lee of the Rockies
over the Northern and Central Plains...generating several areas of
convection along and ahead of it.

As we head into today...deepening upper level trough axis will dig
into the Northern Plains...with a closed upper level low developing
over Minnesota tonight as the upper trough slides into the Upper
Mississippi Valley. Leading edge of deepening moisture ahead of this
system will gradually push eastward into Eastern Upper and Northern
Lower Michigan today and tonight...resulting in increasing chances
of showers and storms from SW to NE across our CWA by this afternoon
and thru tonight. Instability will initially be very limited as
precip develops...thus chances of thunder will be small with no
threat of severe storms thru tonight.

Temps will remain warm today with afternoon highs in the low to mid
80s. Low temps tonight will cool into the lower 60s.

&&

.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
Issued at 247 AM EDT Thu Aug 15 2024

Pattern Synopsis and Forecast:

Main weather feature will be an upper low and subsequent sfc low
pressure & frontal systems for the Friday and Saturday time frame.
Nice fetch of moist air will advect into northern Michigan on Friday
with dewpoint values rising well into the 60s fostering minor to
perhaps moderate instability (depending on the mesoscale evolution
of the environment). Generally "weak" winds aloft, and thus wind
shear generally approaching 20-25kts. All this to say certainly a
marginal environment that may be capable of a couple of robust
storms if they can take advantage of the unstable atmosphere (given
enough clearing and energy remains), marginal wind shear, and
dynamic forcing later Friday. Low level and column moisture are well
above the mean for this time of year and thus pockets of heavy
rainfall will be possible as well, Friday afternoon and into the
overnight. Showers and embedded convection will remain into Saturday
as lift from the upper low tracks right through the center of the
state. Would be very efficient rainfall if convection is able to
manifest given the progged column saturation and skinny capes. Could
be a couple of inches of rain in some areas over the course of the
Friday-Saturday time frame. Minor flooding impacts will be reserved
for training thunderstorms and/or susceptible/poor drainage areas.
Perhaps some lingering showers on the back edge of this system as a
moist atmosphere remains on Sunday, but by the overnight hours
things begin to settle down.

Indications are a quieter period early to mid next week as this
system moves east and a much drier airmass finally filters into the
region (dewpoints drop into the low 50s at least). Will be another
piece of energy in the vicinity of the area mid next week, but the
richer moisture remains well to the west, thus right now have meager
POPs in the fcst in the mid next week. High temperatures in the 70s
for a majority of the fcst period.

&&

.AVIATION /18Z TAFS THROUGH 18Z FRIDAY/...
Issued at 139 PM EDT Thu Aug 15 2024

Worsening conditions tonight into Friday.

VFR presently. Precip now in WI will slowly expand eastward into
northern MI as soon as this evening. Vsbys/cigs will gradually
lower after rain arrives. All sites will become low-end MVFR to
high-end IFR by very late tonight and/or Fri morning. Some
embedded TSRA are also possible tonight.

S to se surface winds, a touch gusty at times.

&&

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

&&

$$

UPDATE...JZ
SHORT TERM...MLR
LONG TERM...JLD
AVIATION...JZ