Onekama, Michigan Weather Forecast Discussion

750
FXUS63 KAPX 181016
AFDAPX
Area Forecast Discussion
National Weather Service Gaylord MI
616 AM EDT Thu Sep 18 2025
.KEY MESSAGES...
- Shower chances favoring areas along and south of a Charlevoix
  to Harrisville line. Slight thunder potential as well,
  greatest chances near Saginaw Bay.
- Sharp temperature gradient today (upper 60s north, to low 80s
  south).
- Turning cooler Friday and Saturday with dry conditions.
  Better rain chances filling in through the weekend as warmth
  and humidity returns Sunday.
&&
.SHORT TERM /THROUGH TONIGHT/...
Issued at 229 AM EDT Thu Sep 18 2025
Ridging in the process of being suppressed by a weak trough cresting
the Plains, in turn forcing a "backdoor" front through the region
from the NNE. Low level jet processes driving some subtle convective
responses over the open waters of Lake Michigan ahead of this
boundary. The front will basically be bisecting lower Michigan
today... with a cloudier and cooler regime holding dominant across
the north half of the APX CWA. Ample postfrontal moisture slug
should be permissive of a pretty stubborn stratus deck across the
far north reaches of northern lower and much of the eastern U.P.
Highs in this area generally hold from the mid 60s to near 70.
Farther south, anticipating more breaks in the clouds and more
sunshine to drive temperatures up the farther south one goes...
generally in the upper 70s along and south of M-72, with spots near
Saginaw Bay possibly touching the mid 80s.
That warmth coupled with a slug of better low level moisture may be
just enough to force some convective processes south of a Charlevoix
to Harrisville line... with the best overall chances favoring near
Saginaw Bay where instability nearing 1000 J/kg should be enough to
break through a capping inversion and produce a storm or two (and
eventually where activity becomes concentrated later this
afternoon). This activity will quickly dissipate after sunset with
the loss of diurnal heating. Lingering clouds will be slow to scour
out tonight, which will prevent the incoming cooler airmass from
really driving radiational cooling tonight. Lows generally in the
mid 50s to near 60 across northern lower (some interior locales
might come close to 50)... lows in the eastern Yoop generally 45 to
50 as the influences of surface high pressure scour some clouds out
late from north to south north of the Bridge.
&&
.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
Issued at 229 AM EDT Thu Sep 18 2025
High pressure and northerly flow will lead to a dry, increasingly
sunnier, but cooler Friday. Highs 65 to 75... coolest eastern upper
and northeast lower amid easterly flow... warmest south of Grand
Traverse Bay. Much of the same Saturday though an approaching system
will lead to a warm front lifting into the area, introducing a
shower chance late in the day Saturday across the western half of
the area. Troughing and attendant surface low over the Plains will
generally move through the region with time Saturday night into next
week. This system will draw in warmer and more moist air to the
region, bringing a more humid tinge to the air as highs spike back
into the 70s to near 80 east of I-75 in northern lower. As such,
this increase in forcing will allow for instability to generate a
much more appreciable chance for showers and storms Sunday. This
system looks to be a bit of a slow mover, which will carry shower
and thunder chances into Monday. The cold front will be advancing
through the region with time Monday... so pattern recognition would
suggest that the best chance for additional showers and storm
activity to produce appreciable rainfall favors northeast lower.
Additional shower potential lingers into Tuesday as moisture is slow
to depart, and with increasingly cooler air aloft intruding
overhead, certainly possible for some diurnal instability to
materialize to drive additional shower chances. Long term guidance
suggests a cooler and drier trend builds in the wake of this
disturbance as we progress through the rest of next week.
&&
.AVIATION /12Z TAFS THROUGH 12Z FRIDAY/...
Issued at 540 AM EDT Thu Sep 18 2025
Lingering BR/FG and low CIGs the main concern through the
morning hours. Areas of BR/FG should lift by 13-14Z most areas,
meanwhile, stratus/low CIGs will continue through the 14-17Z
time frame for KCIU, KPLN, and KAPN. Expect IFR to LIFR CIGs to
lift to MVFR and eventually VFR this afternoon. Generally north
to northwest winds expected today, with a few isolated SHRA and
TS south of M-32. Not confident in impacts at terminals thus no
precipitation mentioned at this time.
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...None.
MARINE...None.
&&
$$
SHORT TERM...HAD
LONG TERM...HAD
AVIATION...JLD

NWS APX Office Area Forecast Discussion