901
FXUS63 KAPX 091059
AFDAPX

Area Forecast Discussion
National Weather Service Gaylord MI
659 AM EDT Wed Jul 9 2025

.KEY MESSAGES...

-Isolated showers and thunderstorms possible across northeast
 lower this afternoon, particularly in the Saginaw Bay area.
 Torrential rainfall over a short period of time is possible.

-Dry weather thursday and Friday.

-Turning humid with more appreciable rain chances over the
 course of the weekend.

&&

.SHORT TERM /THROUGH TONIGHT/...
Issued at 342 AM EDT Wed Jul 9 2025

Current Overview / Pattern Synopsis:

Broad troughing slowly making its way across the Great Lakes
tonight, slowly advancing out of the region by this evening. Broad
1014mb surface low pressure over Lake Michigan will slowly drift
east, riding a stationary boundary that will be drawn northward into
the CWA as the surface low traverses northern lower later today.
Moisture pooling evident across the region as surface dewpoints have
ballooned into the 60s across the board (save for parts of the
eastern Yoop), which will set the stage for diurnal instability to
materialize this afternoon as an inverted surface trough (reinforced
by the Lake Huron marine layer) builds into the region, becoming the
focus for showers and storms later today.

Forecast Details:

Ongoing showers in the vicinity of the Sault will go by the leeway
by daybreak, leaving much of the region dry aside from a rogue
shower across northern lower. Definitely a much more juiced feel
to the air today as dewpoints spike well into the 60s, and highs
peak anywhere from 73 to 83 degrees (warmest south / east). As
far as rainfall goes during the day today, anticipating most of
northwest lower and eastern upper will likely remain dry, aside
from where showers initiate this afternoon, which should occur
along / east of a Lake City to Rogers City line in northern lower.


Anemic flow aloft will lead to slow progression of thunderstorms.
Minimal bulk shear usually wouldn`t suggest a severe threat, though
with a pulse dominant single cell to weakly organized multicell
mode, suppose a stronger to  marginally severe gust is possible with
stronger downdrafts in collapsing storms. As such, SPC convective
outlook has areas south of an Alpena to Houghton Lake line in a
Marginal Risk, driven by a damaging wind threat, and maybe some hail
too with some streamwise vorticity noted in a linear hodograph
shape.

With PWATs spiking over 1.3 (perhaps as high as 1.6), this will set
the stage for torrential rainfall in any isolated showers / storms
this afternoon across northeast lower, with 1 to 2"+ of rainfall
certainly on the table in a short period of time. Deeper moisture
will remain downstate, but with steep lapse rates aloft, we will
still be able to destabilize quite a bit this afternoon across
northeast lower. Even with ample instability (MLCAPE of 1500+ J/kg
across NE lower, particularly Saginaw Bay), CAMs seem to want to
keep coverage of storms isolated across Saginaw Bay, with the focus
of storms maximized by surface convergence across Saginaw Bay,
perhaps as far north as Alpena, in conjunction with a marine layer
enhanced inverted trough. Toyed with the idea of a Flash Flood
Watch in Gladwin, Arenac, Ogemaw, Iosco, and Arenac (which saw
torrential rain Sunday, and thus would be most vulnerable to
hydrologic impacts)... but decided against this owing to
uncertainty in storm coverage and lack of confidence in
impactful hydrological impacts at this juncture. Latest CAMs are
struggling to initiate north of the Saginaw River... so there
is potential that minimal to no storm coverage is realized.
Obviously, this is a trend that will need to be monitored
through the morning, as ongoing convection downstate may
influence how things evolve into the afternoon.

So after all that, expecting this disturbance to finally clear the
region, with less humid air building behind the system. Perhaps some
fog builds later tonight in areas that see rainfall today, but
otherwise an uneventful night in the weather department. Lows 53 to
62.

&&

.LONG TERM /THURSDAY THROUGH TUESDAY/...
Issued at 342 AM EDT Wed Jul 9 2025

Surface high pressure builds for Thursday and Friday, with
convection being confined to the western Corn Belt amid a favorable
MCS setup in that region. Expecting another area of troughing with
numerous embedded waves (possibly convectively charged) to intrude
into the region Saturday into Sunday, which will likely return a
more appreciable rainfall chance in the form of rounds of showers
and storms to the region... pending the timing of this feature`s
passage. Not a glaring signal regarding severe weather with this
pattern, but cannot be ruled out at this time. In the wake of this
troughing`s passage, ridging will quickly build into the region for
next week, which looks to bring warmer high temperatures, albeit,
with somewhat lower humidity. Highs Thursday generally in the lower
80s, warming into the mid and upper 80s Friday, low-to-mid 80s for
the weekend, before warming into the upper 80s again next week. Lows
remain on the mild side... generally in the 60s to near 70 Friday
night and beyond.

&&

.AVIATION /12Z TAFS THROUGH 12Z THURSDAY/...
Issued at 654 AM EDT Wed Jul 9 2025

Pesky low CIGs and VIS hanging around terminals this morning,
which should slowly diminish or lift to VFR over the next couple
of hours. Potential for ISO -SHRA/-TSRA in the vicinity of KAPN
this afternoon, other locations remain dry and VFR. Another
round of FG will be possible later tonight. Winds northwest for
most, easterly near lake huron due to the lake breeze.

&&

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

&&

$$

SHORT TERM...HAD
LONG TERM...HAD
AVIATION...JLD