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000
FXUS63 KAPX 271437
AFDAPX

Area Forecast Discussion
National Weather Service Gaylord MI
1037 AM EDT Tue Sep 27 2016

.UPDATE...
Issued at 1020 AM EDT Tue Sep 27 2016

Pretty steady state weather across the region with an upper and
sfc low over Lake superior dropping slowly due south. Deep
moisture is wrapped around the low pressure with several
individual shortwaves/vorticity maxima. One is working across nrn
Michigan attm, with stronger forcing driving around the SW flank
of the upper low later tonight. Regardless, WSW cold low level air
flow over the warmer waters continues to result in lake effect
rain showers. Winds go more variable tonight with the core of the
sfc low and best low level convergence dropping through Lake
Michigan. This low level convergence will bring the best chances
of showers along that sfc low path. Thermally, we will remain cold
enough for lake processes, but wildly backing low level winds will
disrupt the ability for lake bands to set up out of a more
easterly direction. Will treat this scenario with definite
showers while the low level wind fields remain fairly steady out
of the WSW today, then go more scattered through tonight.

Still seeing at least a slight chance for a clap of thunder with
a few hundred j/kg of CAPE. Lake induced convective cloud
depths/delta t scenario still looking to provide low to moderate
chances for waterspouts, especially over Lake Superior and nrn
Lake Michigan.

SW/WSW wind gusts to slowly weaken through the day, and especially
tonight.

&&

.SHORT TERM...(Today and tonight)
Issued at 345 AM EDT Tue Sep 27 2016

Deep vertically-stacked low remains centered along the northern
shore of Lake Superior early this morning...with deep cyclonic flow
and plenty of moisture wrapping around this low across the northern
Great Lakes region. Lake-enhanced rain showers continue to stream
into the Straits area and far Northern and NW Lower Michigan
directed by W/SW low level flow off of Northern Lake Michigan.
Ongoing CAA has increased surface to 850 mb delta T`s to the mid
teens...and combined with deep cyclonic flow and ample moisture...
widespread rain showers continue to impact the above outlined areas.

Little will change as we head thru today and into tonight.
Vertically-stacked low center will drop directly south thru
Wisconsin and Michigan over the next 24 hours...reaching Southern
Lake Michigan by 12Z Wednesday. Persistent deep cyclonic flow will
maintain strong convergence over our area. Delta t`s will remain in
the mid teens as 850 mb temps hold around +4 C with lake temps
holding between +18 C and +20 C. Low level winds will remain from
the W/SW thru this evening...but will begin to disorganize overnight
as the low center passes to our SW. This will likely reorient the
focus of lake-enhanced rain showers...but this process will take
some time to reorganized to a more NE orientation...and should not
really take hold until after 12Z Wednesday. Thunder has been hard to
come by overnight...but still cannot rule out a slight chance of
some embedded thunder development as 500 mb temps hold around -20 C.
Will keep a slight chance of thunder in the forecast for areas
targeted for highest POPs thru tonight (in agreement with latest SPC
Day 1 outlook of general thunder).

Expect another cool and breezy day across the Northwoods (but not
quite as breezy as yesterday). Temps will not warm very much from
current obs...with high temps generally in the mid 50s to around 60
degrees. Low temps tonight will cool back into the mid 40s to around
50.

.LONG TERM...(Wednesday through Monday)
Issued at 345 AM EDT Tue Sep 27 2016

The main weather player to affect northern Michigan over the next
several days still looks like it will be the upper level low evident
on water vapor imagery spinning across south central Ontario. This
system will sink slowly southward over the next couple of days then
stall out across the northern Ohio Valley before likely heading back
northward later in the week into this weekend. Models have come into
better agreement on the details but differences remain over the
exact movement and timing. The main forecast concerns will continue
to revolve around pops and temperatures.

Wednesday...scattered to numerous rain showers will continue as the
upper low slides by to our south. Still cold enough for some lake
enhancement with lake/850 mb delta ts in the middle teens. The most
persistent rain shower activity looks to be across eastern zones as
the mean flow is out of the east off of Lake Huron. Highs generally
in the lower 60s.

Wednesday night...still plenty of lingering moisture and perhaps
some leftover showers Wednesday night across eastern zones as the
upper low takes its time pushing off to our south. Lows in the upper
40s and lower 50s.

Thursday into Thursday night...kind of a lull in the action as drier
air works its way south as the upper low stalls out. Just a chance
for lingering rain showers across southeast counties Thursday with
pops expanding a bit northwestward overnight Thursday as the upper
low begins to edge to the north. Highs in the lower and middle 60s
and lows in the upper 40s and lower 50s.

Longer range (Friday through Monday)...So as stated above, models
are finally converging on the solution of bringing the upper low
back to the north (at least closer). The ECMWF remains the most
bullish over this idea with the GFS still farther south and east but
much closer to the ECMWF solution than any of the previous runs.
Either way, scattered to numerous showers are expected to expand
northward Friday and remain across the region through much of the
weekend. The upper low finally lifts away from the region Monday
yielding decreasing clouds and milder temperatures.

&&

.AVIATION...(For the 12Z TAFS through 12Z Wednesday morning)
Issued at 645 AM EDT Tue Sep 27 2016

Overall conditions will remain low VFR/high MVFR thru Wednesday
morning despite continued production of lake-enhanced rain showers
as deep low pressure drops south thru Lake Michigan. Best chance
for rain will remain over the Straits area and far Northern/NW
Lower Michigan (PLN) under the direction of low level SW flow.
Winds will begin to reorient to the NE late tonight as low
pressure passes to our SW. Winds will remain from the SW at 15 to
25 kts into this afternoon...but will diminish late in the day and
thru tonight as the low center passes just to our west.


&&

.MARINE...
Issued at 345 AM EDT Tue Sep 27 2016

Winds will very slowly diminish today and tonight as low pressure
drops south thru Lake Superior...reaching Southern Lake Michigan by
12Z Wednesday. Wind speeds have generally dropped below gale force
early this morning...but will remain at SCA criteria thru tonight.
Conditions should diminish further tonight...falling below SCA
criteria during the evening. Lake-enhanced rain showers will
continue to impact portions of our nearshore areas...targeting the
Straits and Lake Michigan nearshore areas for best chances of rain
thanks to W/SW low level flow. Winds will shift to the NE by
Wednesday...refocusing highest POPs into NE Lower Michigan.


&&

.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...SMALL CRAFT ADVISORY until 6 PM EDT this evening for LHZ345>349.

LM...SMALL CRAFT ADVISORY until 6 PM EDT this evening for LMZ323-341-
     342-344>346.

LS...SMALL CRAFT ADVISORY until 6 PM EDT this evening for LSZ321-322.

&&

$$

UPDATE...Dickson
SHORT TERM...MLR
LONG TERM...Sullivan
AVIATION...MLR
MARINE...MLR