464
FXUS63 KAPX 031049
AFDAPX

Area Forecast Discussion
National Weather Service Gaylord MI
649 AM EDT Wed Sep 3 2025

.KEY MESSAGES...

- Cold and unsettled weather into the weekend

- Gusty winds/gales possible Friday?

&&

.SHORT TERM /THROUGH TONIGHT/...
Issued at 359 AM EDT Wed Sep 3 2025

PATTERN SYNOPSIS/FORECAST:

Ridging over the western US, with broad troughing holding fast over
the eastern US...as lingering upper low hangs out over the Lower
Great Lakes. The arctic is open for business, with N-NNW flow
crashing into the northern Plains on a 100+kt upper jet...and 850mb
temps dropping below zero across the Canadian Prairies in the wake
of a bowling ball of PV spiraling southeastward from Manitoba; temps
at 7z in the 40s behind this, while holding onto the 50s/60s ahead
of it. Nice inflection point PV noted over the Arrowhead of MN,
ahead of the primary bowling ball as of 7z, generally attendant to
surface low pressure over Lake Superior. Cold front drapes from this
back into Nebraska...and loops back up toward the Canadian Rockies,
with a cold high pressure in its wake. While better moisture remains
locked near the Lower MS Valley and Gulf Coast...a plume of higher
pwats stretches up through the MS Valley into the Midwest and into
southeast Canada, generally along aforementioned cold front.
Scattered convective activity along/ahead of the front across the
Upper Great Lakes early this morning with a little warm advection
ahead of the primary cold front.

Expect cold front to plow into the region this afternoon from west
to east, with showers and thunderstorms likely along/ahead of it. A
dry slot comes through aloft late in the afternoon as the primary PV
niblet swings through, which could keep the threat of convective
activity going a bit longer into the evening. With temperatures
plummeting below 5C at 850mb late this afternoon, expect overlake
instability to ramp up, leading to some lake-effect rain showers
going into tonight.

Primary Forecast Concerns through Tonight:

Rain/storms today... Looking like a decent shot at thunder today,
actually, with guidance soundings showing a few hundred joules of
CAPE, some of which starts out as elevated instability this
morning...but given increasing synoptic forcing (along with some
potential for diurnal heating on the Sunrise Side), it should become
uncapped prior to fropa. Not that there will be a lot of CAPE,
necessarily, but enough to keep things a little interesting
today...particularly as wind fields should start to get a little
better as the LLJ picks up ahead of the cold front. Better deep-
layer shear looks to be post-frontal, which is something to keep in
mind with dry slotting aloft punching in this afternoon (which could
boost convective instability). Overall...think showers/storms will
generally move in from west to east (perhaps with a bit of a
northward component along the front) this morning, though there is
potential for some development/redevelopment across NE Lower MI
toward late morning/midday, likely associated with the initial punch
of warm advection activity crossing the central Yoop as of 5z.
Primary threats with any stronger storms would be small hail,
especially as freezing levels should start to come down today...and
potentially some gusty winds, with those 30-40kt winds up through
700-850mb.

Locally heavy rainfall will remain a threat today...as we will be
faced with excellent forcing in the presence of a climatologically
moist atmosphere (pwats around 1.3 inches would be up around the
90th percentile for us for early September). Narrow/skinny cape
profiles, and warm cloud layers up through 2.5-3km ahead of the
front, also lend credence to the idea of somewhat more efficient
rainfall processes... and not surprised to note probabilistic
guidance strongly suggesting 1-in/6-hr rainfall rates are possible
today, especially this morning through mid-afternoon across the EUP
and Tip of the Mitt (hi-res probs are around 60-80 percent). Less
confidence in better rainfall rates/totals across NE Lower, though
worth noting there are some non-zero chances of localized 2-inch
totals there by Thursday morning. Potential sticky wicket for heavy
rain concerns is that the front should be fairly progressive, with
the deepest moisture getting swept out by 0z Thu, as this could
limit how long the heavy rainfall stays over an area...but still
worth keeping an eye on, in case things slow down a bit (which is
possible).

&&

.LONG TERM /THURSDAY THROUGH TUESDAY/...
Issued at 359 AM EDT Wed Sep 3 2025

Days 2-3 (Thursday-Friday)...

A slight break in the action Thursday as we sit between
systems...though temperatures, as mentioned above, will be cold
enough to support overlake instability and subsequent lake effect
rain showers for parts of the area. Next niblet of PV dives into the
Midwest Thursday night into Friday morning, driving surface low
development across the region and reinforcing cold air over the
region. Highs look to remain in the 50s through the end of the
week...about 15-20 degrees cooler than this time of year. Lows could
be problematic for frost/freeze concerns, but potential cloud cover
with the parade of systems could keep temps up above concerns for
now.

Brisk Winds Friday....Next system to spin up appears to tighten up
over us halfway early in the day Friday...and expect strengthening
winds in the area...though exact details will be tied to where the
center of the low ends up. Attm...strong signals for brisk SW winds
across SE MI into Lake Huron ahead of the front...and will expect
strong N/NW winds as it passes by. Winds aloft are better with this
system, too, suggesting we could have stronger wind gusts, too,
along with plain old sustained winds. Think there is a reasonable
shot at the first widespread gales of the fall season over the
lakes, with 40kt winds possible at 850mb.

Days 4-7 (Saturday-Tuesday)...

Expecting another couple shots of PV this weekend...the first of
which slips in Saturday, followed closely by another potential
niblet later Saturday evening into Saturday night...both of which
will keep the cool, unsettled, fall-like idea in play...with highs
likely topping out in the 50s to near 60 at best. Looking like
ridging will try to build in at some point Sunday into
Monday...though some uncertainty attm in how quickly this occurs,
which could impact how quickly frost/freeze concerns slip back into
the picture (Saturday night at fastest...but more likely Sunday
night, overlake instability and lake effect clouds notwithstanding).
Another system looks to drop in for Monday night and Tuesday, which
could bring southwest flow and a little warmth back to the picture.

&&

.AVIATION /12Z TAFS THROUGH 12Z THURSDAY/...
Issued at 644 AM EDT Wed Sep 3 2025

Worsening conditions today. Showers and a few TSRA will
expand into the area from the west, as a cold front makes steady
progress into northern MI. The most likely sites to see TSRA are
CIU this morning, and APN this afternoon. Cigs/vsbys will
lower; all sites become MVFR by early afternoon. At least brief
IFR conditions are possible. IFR cigs are likely for part of the
afternoon at CIU/PLN. Conditions improve to VFR late tonight.

Sw winds become gusty after sunrise, eventually becoming nw
this evening.

&&

.APX WATCHES/WARNINGS/ADVISORIES...
MI...Beach Hazards Statement through this evening for MIZ016-025-
     031-098.
MARINE...Small Craft Advisory until 11 PM EDT this evening for LHZ345.
     Small Craft Advisory until 11 PM EDT this evening for
     LHZ346>349.
     Small Craft Advisory until 11 PM EDT this evening for LMZ323-
     341-342-344>346.
     Small Craft Advisory from 1 PM this afternoon to 5 AM EDT
     Thursday for LSZ321.

&&

$$

SHORT TERM...FEF
LONG TERM...FEF
AVIATION...JZ