761
FXUS63 KAPX 010759
AFDAPX

Area Forecast Discussion
National Weather Service Gaylord MI
359 AM EDT Tue Sep 1 2026

.KEY MESSAGES...

- Rain/storms in play the next few days. Heavy rain and strong
storms possible tonight through at least Thursday or Friday.

&&

.DISCUSSION...
Issued at 358 AM EDT Tue Sep 1 2026

PATTERN SYNOPSIS/FORECAST:

Broad pattern has ridging over the CONUS/North America, particular,
the eastern half...with +2 standard deviations from the mean upper
ridge over Hudson Bay...and similarly anomalous southern stream
ridge centered over the Mid MS Valley. A 554dm 500mb low is plowing
its way through the ridge axis attm, currently spinning over central
Manitoba, with a strong height rise/fall couplet across southern
Canada associated with this...and very occluded 1000mb surface low
smack dab beneath the upper low, with a surface cold front
stretching down into the central Plains. Very warm and sticky ahead
of this front, with dewpoints largely in the 70s across WI and much
of northern Lower south of a stagnant stationary front stretching
from western Lake Superior through the Straits and toward New York
and the Mid-Atlantic; pwat on our 0z sounding was 1.66in. Lots of
fog/low-clouds continue to hang out near and north of the stationary
boundary across the Yoop and parts of the Straits/Tip of the Mitt.
Very warm airmass in place, characterized by 700mb temps around +10-
12C, and freezing levels of 15kft on our 0z/01 sounding. Attm, low-
level jet is stronger to our northwest nearer to the upper low, and
to our southeast across SE MI. Approximately 2000J/kg CAPE on our
evening sounding, with some minor CINH, which is generally
representative of the region attm...the bulk of which is going
untapped as of 4z, with little in the way of forcing in the region
attm.

Upper low looks to track just to our north through Wednesday,
weakening to some extent as it does so, dragging a boundary into the
area and leaving it for a while. Upstream, broad upper low digs into
the PacNW, resulting in ridge axis generally strengthening over the
Central Plains/Upper Midwest later this week, which should bring
warm advection and some potential convection to the Upper MS Valley
through the end of the week. We should remain largely in the
vicinity of aforementioned lingering baroclinic zone through the
remainder of the week, and thus, hold onto the threat of periodic
unsettled weather into the start of the holiday weekend -- much of
which may be dependent on how early/late day convection evolves
(i.e., higher uncertainty than usual). Some uncertainty in the
evolution of the northern stream pattern across central Canada this
weekend, depending on a lobe of energy crossing the top of the
ridge, and whether or not the ridge is able to block northern
Canadian energy from sinking southward into eastern Canada for early
next week. This could mean the difference between a slightly warmer
end to the Labor Day weekend...or a warmer and slightly more active
one.

FORECAST DETAILS...

Rain/storm potential the next few days...With signals for the
boundary to drape in today, and that PV max to slide by just to our
north...not impossible there could be enough forcing around to pop
something today. Relatively light low-level flow also suggests lake
breezes will come into play, particularly across northern Lower MI,
which could play a role in boosting pop-up showers/storms,
especially this afternoon. If we end up clearing out today,
certainly possible the cap could be broken as well, with potential
for 1500-3000J/kg CAPE here, given weak stability aloft. Think this
idea will depend on what happens yet this morning, and there is some
potential for activity to develop prior to 12z, though forcing will
not be super great. Deep layer shear should pick up early this
morning as the nose of the 500mb jet enters the region, and will
remain at or above 40kts through the day...suggesting that anything
that gets going will have support for organization. With the
potential for that boundary to turn zonal this
afternoon/evening...think upscale growth could be a concern. Deepest
moisture may end up well to our south, across southern Lower today,
and we may well tap into some drier air aloft that could limit
shower/storm activity... but will still be close enough to warrant
some beefier rainfall totals.

Better rainfall chances should come tonight into Wednesday as the
low-level jet strengthens closer to our area, allowing for better
support of nocturnal convection and moist advection off the zonal
boundary likely to stall just to our south tonight and slowly drift
back northward/northeastward Wednesday. Better instability
parameters may remain near and south of M-72...which could result in
most, if not all, the stronger storms staying south. However,
appears we should still have around 40kts deep layer shear to work
with...and another afternoon of upscale growth potential, with shear
vectors parallel to the boundary; weak low-level flow again should
support the idea of lake breezes and potential for localized
convergence to enhance any storms. Other concern is that pwats
should be on the rise again Wednesday, supportive of another
increased risk of heavy rainfall/localized flooding potential across
the area.

Boundary looks to wiggle back and forth across the area the next few
days...and think this will keep the threat of heavy rain in play
into at least Thursday, if not longer. Thunderstorms will also
remain in play, with the warm/unstable air mass in the vicinity and
some better deep-layer shear at times to support a threat for
stronger, more organized activity from time to time...but will
depend on how far north/south that boundary fluctuates through the
next couple days...perhaps into Friday/Saturday as well, pending the
evolution of energy riding the ridge later this week. This latter
idea is again supportive of activity developing along the upstream
perimeter of the ridge axis and could track into the Upper Great
Lakes...so will need to keep an eye on it as well. Fluctuating
boundary will also keep some portions, particularly near and south
of M-72/M-55, more likely to stay warmer and more muggy through the
period, with lesser dewpoints likely across the EUP going forward.

&&

.AVIATION /06Z TAFS THROUGH 06Z WEDNESDAY/...
Issued at 1049 PM EDT Mon Aug 31 2026

Still expecting an expanding stratus field and fog/mist to
return early this morning across much of the area. Improvement
area- wide to VFR expected heading through this morning, with
skies trending mostly sunny through the afternoon. Some
increasing high and mid level clouds expected this evening. Light
winds expected through the period.

&&

.APX WATCHES/WARNINGS/ADVISORIES...
MI...Dense Fog Advisory until 9 AM EDT this morning for MIZ086>088-
     095>098.
MARINE...Dense Fog Advisory until 4 AM EDT early this morning for
     LHZ345>347.
     Dense Fog Advisory from 9 AM this morning to 2 PM EDT this
     afternoon for LHZ345>347.
     Dense Fog Advisory until 4 AM EDT early this morning for
     LMZ341-342.
     Dense Fog Advisory from 9 AM this morning to 2 PM EDT this
     afternoon for LMZ341-342.
     Dense Fog Advisory until 4 AM EDT early this morning for
     LSZ321-322.
     Dense Fog Advisory from 9 AM this morning to 2 PM EDT this
     afternoon for LSZ321-322.

&&

$$

DISCUSSION...FEF
AVIATION...MSB