Area Forecast Discussion
Issued by NWS Gaylord, MI

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FXUS63 KAPX 260743
AFDAPX

Area Forecast Discussion
National Weather Service Gaylord MI
343 AM EDT Mon Sep 26 2016

.SHORT TERM...(Today and tonight)
Issued at 323 AM EDT Mon Sep 26 2016

It had to happen sometime...didn`t it? A true taste of northern
Michigan early fall weather about to make its presence felt behind a
strong cold front currently making steady progress into northwest
lower Michigan. Well organized band of showers running just ahead
of this front within corridor of some impressive late September
moisture (precipitable water values up around one and a half
inches). All the above tied to one rather vigorous shortwave
trough currently digging into the northwest Lakes. This system
will continue to deepen, eventually fully closing off, on its ever
slowing journey across the northern Lakes today and tonight. Deep
moisture pinwheeling around this system, augmented by burgeoning
lake processes with arrival of much colder air, will result in
more showers through the short term period. Throw in increasingly
gusty winds, and its definitely gonna look and feel like early
fall.

Cold front will complete its journey across the area this morning,
with deep mid level troughing following for this afternoon. Main
corridor of rain will exit with the front itself, with mid level dry
slot following quickly behind it. This will put an end to the
widespread showers quickly this morning. Shower coverage expected
to ramp up again by later this afternoon and evening as deep
moisture wraps back overhead. Lake processes will also increase as
h8 temperatures dip into the lower and middle single digits. This
is more than cold enough with Lake Michigan temperatures still
running around 20c. Some rather impressive looking forecast
soundings, with lake induced equilibrium levels in excess of 20k
feet. Given this, some of those lake showers could be briefly
heavy, especially in those favored west southwest flow areas.
A raw, increasingly windy day otherwise, with high temperatures
for a change running a touch below normal (would be one of only a
handful of days since the start of summer).

More of the same tonight, with lake processes expected to become
even more organized as moisture further deepens and waves rotate
around center of parent system. West southwest flow remains,
targeting those tip of the mitt counties. Soundings remain
impressive, with equilibrium levels well over 20k feet and decent
cape through the mid levels...suggesting the potential for heavy
showers, accompanied by perhaps a few claps of thunder. Given near
steady-state wind fields and lake driven instability, could be
looking at some rather impressive rainfall totals by morning in
those favored areas. Scattered showers expected elsewhere across
the area. Gusty winds and cloud-filled skies will keep
temperatures from falling too much, with lows mostly in the mid
and upper 40s.

.LONG TERM...(Tuesday through Sunday)
Issued at 323 AM EDT Mon Sep 26 2016

The main weather player across northern Michigan over the next
several days is the upper level low evident on water vapor imagery
just south of the Arrowhead of Minnesota. This system will continue
to sink southeastward over the next couple of days then stalls out
across the northern Ohio Valley before likely heading back northward
later in the week into next weekend. This could wreak havoc on the
ongoing forecast and ruin what once looked like pleasant early
autumn weather to end the week into next weekend. The main forecast
concerns will continue to revolve around the movement of this system
and the resultant cloud, precipitation and temperature fields.

Numerous rain showers and possibly even a few rumbles of thunder
will continue Tuesday into Tuesday night along with blustery and
cool conditions as the upper low slowly slides down Lake Michigan.
It will be cold enough for lake enhancement as well as 850 mb
temperatures drop into the lower single digits above zero yielding
lake/850 mb delta ts in the middle to upper teens.

Still plenty of lingering moisture and perhaps some leftover showers
Wednesday as the upper low takes its time pushing off to our south.
Could even see showers hang on into Wednesday night across
southeastern zones.

Longer range (Thursday through Sunday)...the ECMWF and UKMET with
support from some the the GFS ensemble members continue to
retrograde upper low back northward over the coming days. In fact,
the ECMWF has the center of the closed circulation just east of
Alpena at 06z Monday morning. This does not bode well for clearing
except for across eastern upper. In good conscience and after
collaborating with neighboring offices had to at least introduce low
chance pops (as a start) from Thursday all the way into next
weekend. The worse case scenario would keep clouds and occasional
showers and cooler temperatures going right on through much of this
time period.

&&

.AVIATION...(For the 06Z TAFS through 06Z Monday night)
Issued at 1143 PM EDT Sun Sep 25 2016

Cigs decreasing to MVFR to IFR levels overnight into Monday
morning.

Cold front will advance east from eastern WI tonight. Showers/few
TSRA will occur, diminishing from w to e very late. After a
relative lull Monday morning, rain coverage will increase again
in nw lower MI in the afternoon as cooler air moves in and lake
effect develops. Cigs will lower overnight, with MVFR to IFR
conditions developing. Improvement to marginal MVFR/VFR conditions
by afternoon.

Se to s surface winds tonight, a bit gusty at times. LLWS ending
overnight. Winds will veer sw to w and become rather gusty on
Monday.

&&

.MARINE...
Issued at 323 AM EDT Mon Sep 26 2016

Just downright unpleasant for the next few days across the big
waters as deep upper level low pressure slowly drops through the
region. Winds will continue to increase in speed today as they veer
to a west southwest direction behind a departing cold front, with
these gusty west southwest winds continuing through tonight. SCA
conditions a given on all waters, and would not be completely
shocked to see isolated gale force wind gusts in the Manitou Passage
where funneling will be maximized. Gusty winds remain right through
Tuesday, with speeds slowly decreasing heading through Tuesday
night, and especially during the day Wednesday.

From a thermodynamic perspective, conditions look rather decent for
waterspouts later today into tonight with increasing over-water
instability resulting in impressively deep convective cloud
depths. Winds, however, continue to look a bit too strong for a
significant waterspout outbreak. Better waterspout conditions look
to arrive later Tuesday through early Wednesday as the upper
level low drops directly overhead, lightening the wind speeds
while maintaining a rather favorable thermodynamic environment.

&&

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

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

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

&&

$$

SHORT TERM...MSB
LONG TERM...Sullivan
AVIATION...JZ
MARINE...MSB



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