865
FXUS63 KAPX 181829
AFDAPX

Area Forecast Discussion
National Weather Service Gaylord MI
229 PM EDT Sat Oct 18 2025

.KEY MESSAGES...

- Widespread rain, some heavy, returns tonight and Sunday as strong
Fall storm visits the region.

- Gusty northwest winds, producing widespread gale conditions
across the big waters, will also accompany this system.

- Another strong system set to arrive Tuesday, bringing more
wind-driven showers.

- Much more normal late October temperatures heading through
  this upcoming week.

&&

.SHORT TERM /THROUGH TONIGHT/...
Issued at 220 PM EDT Sat Oct 18 2025

Pattern Synopsis/Forecast:

Weak cold front continues to make ever slow progress east into the
western Great Lakes early this afternoon as deep layer flow become
increasingly parallel to it. Deep moisture advection within remnants
of low level jet and development of marginal low level instability
well ahead of this front still helping kick off a broken band of
showers across parts of northern lower Michigan. Another mild day
for October...with current temperatures punching well up into the
60s.

Main emphasis through the near term centers on vigorous upper level
wave currently digging east into the northern and central Plains.
Classic dual upper jet core maxes associated with this
troughing...all of which will work in tandem to entice cyclogenesis
along earlier mentioned cold front tonight across the northern Ohio
Valley. Expect this low to steadily deepen as it races northeast
along the front into lower Michigan and Lake Huron on Sunday.

Primary Forecast Concerns:

Addressing wide range of impacts with the Sunday system...with
emphasis centered on rain evolution/amounts and gusty winds.

Details:

Likely to see a few additional showers continue to percolate across
parts of northern lower Michigan this afternoon, with trends
supporting a dry evening as initial remnants of deeper moisture
convergence pivot off to our east (although will likely see some
patchy fog with a still moist low level environment). Strong
dynamics within deep sub-tropical moisture plume set to drive rapid
shower expansion across the northern Ohio Valley and southern Lakes
this evening, with this precipitation expanding rapidly northeast
into our area later tonight through Sunday as deepen low pressure
pivots up across Lake Huron. Classic widespread deformation and
embedded frontogenetical driven rains northwest of this system
across the Northwoods on Sunday. Pattern recognition per expected
low propagation still supports focus for greatest deep layer
moisture convergence with enhanced deeper convective elements will
be centered near Saginaw Bay and points southeast. Could easily see
rain totals by later Sunday in excess of 2 inches in this region.
Definitely enough to support some ponding on roadways, especially as
we are in the leaf blocking drain season. Expect fairly widespread
half inch to inch+ plus amounts elsewhere, with those inch plus
amounts centered in corridors of greater fgen responses. As for any
severe thunderstorm potential...that threat looks to remain well to
our south and southeast within the warm sector.

Gusty winds will be another concern with this system given
tightening pressure gradient (fall/rise pressure couplet) within
favorable backside system cold air advection regime. Downward
momentum transfer properties per Bufkit guidance sounding analysis
show frequent northwest gusts in excess of 30 mph Sunday...with even
higher gusts near the Lake Michigan coast. Speaking of those big
waters...gale force wind gusts are expected, probably
nearing/exceeding 40 knots at times...especially across Lake Huron
where coastal convergence will be maximized. Appropriate gale
warnings have already been issued.

&&

.LONG TERM /SUNDAY THROUGH FRIDAY/...
Issued at 220 PM EDT Sat Oct 18 2025

Pattern Synopsis/Forecast:

Low pressure will continue to race northeast Sunday night...quickly
taking the main impacts along with it. Next dynamic wave set to
arrive Tuesday with digging shortwave and renewed upper level jet
energy digging into the Lakes. Pattern tries to relax some
thereafter, with core of troughing rotating to our northeast as
ridging builds across central NOAM.

Primary Forecast Concerns:

Addressing impacts with that Tuesday wave.

Details:

Expect rather steady improvement Sunday night as rain departs and
winds subside. Break continues into Monday before that next vigorous
wave digs into the area Monday night and Tuesday. Unlike its
predecessor, this system will not have a direct connection to deep
subtropical moisture. However, simple dynamics will compensate
aplenty, likely driving bands of showers across the area Monday
night through at least Tuesday night, with those showers
increasingly augmented by what should be increasing lake moisture
contribution within the cooling low level environment. Gusty winds
again look likely...especially focused on those big waters where
gale force winds gusts are a definite possibility. Will also have to
be on the lookout for some waterspouts along any axis of enhanced
lower level convergence as closed mid level circulation passes
directly overhead.

As previously mentioned, pattern attempts to relax the second half
of the week as core of troughing begins to pull off to our
northeast. Still some shower possibilities at times with weak lake
processes and with any passing weak waves within departing troughing.

High temperatures through the week definitely will feel much more
like typical late October, with highs mostly in the 50s through
Friday (may even see some locations not even break 50 Tuesday and
Wednesday). While cool, overnight lows do not look too
extreme...with clouds, wind, and occasional showers keeping readings
mostly in the 30s and 40s.

&&

.AVIATION /18Z TAFS THROUGH 18Z SUNDAY/...
Issued at 141 PM EDT Sat Oct 18 2025

IFR/MVFR conditions slowly fade through the afternoon for most
terminals, with a few -SHRA hanging around. Bulk of the
precipitation comes later tonight, ~ arriving by 06-10Z. CIGs
thus lower to IFR again and at times LIFR Sunday morning and
midday with RA, some cases +RA (most likely KAPN). Prior to the
precipitation arrival, CIGs & VIS may lower due to abundant low
level moisture during the evening and early overnight hours,
especially PLN and CIU. Northwest winds begin to pick up during
the midday and then especially Sunday afternoon, 15G30KTs
possible.

&&

.APX WATCHES/WARNINGS/ADVISORIES...
MI...None.
MARINE...Gale Warning from noon Sunday to 5 AM EDT Monday for
     LHZ345>349.
     Gale Warning from 8 AM to 11 PM EDT Sunday for LMZ323-341-342-
     344>346.
     Small Craft Advisory from noon Sunday to 5 AM EDT Monday for
     LSZ321-322.

&&

$$

SHORT TERM...MSB
LONG TERM...MSB
AVIATION...JLD