Area Forecast Discussion
Issued by NWS Cleveland, OH

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000
FXUS61 KCLE 042037
AFDCLE

Area Forecast Discussion
National Weather Service Cleveland OH
337 PM EST Sun Dec 4 2016

.SYNOPSIS...
An upper disturbance and surface trough will cross the region
tonight. High pressure moves overhead for Monday...but the next
system will be just upstream for Tuesday as an active pattern
continues this week. Colder temperatures are on the horizon for
Thursday through the end of the week as well as lake effect snow.

&&

.NEAR TERM /THROUGH TONIGHT/...
Fairly expansive precipitation shield headed our way as a trough
pivots across the Midwest and Great Lakes tonight. Rain/snow line
will be close to nw OH/se MI this evening. Fortunately
precipitation is only expected to be around for 5 or 6 hours and
the deeper moisture exits to the northeast fairly quickly. Figure
as long as we can keep a southerly component to the flow in the
lowest levels...we should maintain predominately rain/occasional
mix. There is room for us to evaporatively cool...but dewpoints
should be getting real close to freezing. Have maintained the
half inch or so accumulations for the Toledo vicinity. Extreme
eastern Erie/Crawford counties /PA/ may see more snow than
rain...with an inch to an inch and a half type accumulations.
Little or now elsewhere. Flow begins to veer after 10 PM...but by
then drying will be working in from the southwest. Temperatures
will be in the mid 30s through the evening...dropping closer to
freezing overnight.

&&

.SHORT TERM /MONDAY THROUGH WEDNESDAY NIGHT/...
Light precipitation may be lingering across far ne OH/nw PA early
Monday morning...but high pressure moves over the area quickly.
Deeper moisture will have exited so it will be difficult to
support snow at that point. Otherwise weak warm air advection and
surface ridging will provide for a seasonable fair weather day.

Next chance of precip moves into the area Tuesday as southern
stream shortwave/attendant surface low tracks northeast through
the Ohio valley. Although there is a bit better timing consensus
with the guidance...the NAM still remains the fastest. Depending
on the arrival time of the precipitation...we may have some precip
type issues to deal with Tuesday morning across the
south/southwestern counties. Monday night lows will likely be
below freezing...but possibly rise just enough before the precip
to not be a problem. For now just mentioned a generic rain/snow
mix. Transition everyone to rain...but depending on the track and
speed of the low...a slower further east track would bring the
rain/snow line real close to Toledo again. Again this is a
relatively quick shot of precipitation.

The first bit of the cold air begins to arrive Tuesday night and
high pressure noses down across the Ohio Valley. Shortwave energy
will move through the base of the mean trough Wednesday. This will
be enough support to keep the precipitation chances across the
entire area Wednesday night. At this point precip would be all
snow...with lows in the mid/upper 20s.

&&

.LONG TERM /THURSDAY THROUGH SUNDAY/...
The long term begins Thursday with models in agreement showing a
short wave moving through the Ohio valley out of the central plains.
At the surface, a cold front will be to our east and 850mb temps
will be -6 to -10c depending on model. The airmass will be plenty
moist for precip and with flow off the lake, lake enhancement can be
expected across the snowbelt. Will have chance pops for snow showers
everywhere increasing to categorical from eastern Cuyahoga county
east across NWRN PA. Thursday into Friday an upper low swings
southeast across the Great Lakes. Winds will remain northwest which
continue to look favorable for lake effect/enhanced snow with
synoptic moisture, moderate to extreme instability and deep lift
through the snow growth region of the sounding.  Friday night the
upper low moves east as high pressure tries to build in from the
south.  This will back winds to the southwest taking any bands
offshore.  To our west however a rather extensive area of isentropic
lift from southern Indiana to the Dakotas will move northeast
affecting the region Saturday into Sunday. Models differ on the
amount of moisture that gets into the area but did bring in chance
and slight chance pops to the area saturday night to Sunday.  All
precip will be snow. Temps below normal with highs only in the
20s and 30s.

&&

.AVIATION /18Z Sunday THROUGH Friday/...
VFR conditions across the area to start this afternoon. Expect
cigs to lower from the west after 20z dropping to MVFR around 22z
at KTOL and KFDY as precip west of the area moves in. Expect a
drop to IFR lasting 4 to 6 hours in rain or a rain snow mix before
lifting back to a low MVFR CIG after 06-08z as precip ends. This
trend will remain in place further east with KCLE dropping to MVFR
by 02z and KERI by 04z. High pressure and drier air build in
quickly after midnight from the west however looking at forecast
soundings...a sharp inversion is evident which will trap low level
moisture across the area keeping CIGS MVFR through 18z. Cigs will
likely break with conditions turning VFR from the west by late
afternoon and is only contained in the KCLE taf after 22z.

OUTLOOK...Non-VFR conditions Monday afternoon lifting from the
west into the evening. Frequent non-VFR Tuesday afternoon through
Friday.

&&

.MARINE...
An active pattern this week. The most significant for marine
interests will come Thursday into Friday. A small craft headline
is a given and brief northwest gales are possible as the gradient
tightens between high pressure in the central plains and low
pressure in northern New England. In the near term a trough of low
pressure will cross the lake overnight from the west. East-
southeast flow 10 to 15 knots will turn west and increase to 15 to
20 knots after midnight. Winds will slowly taper on Monday. Waves
will increase to near 4 feet for a short time central and east
from late morning through early afternoon. A small craft may be
needed but at this time is borderline. Monday afternoon high
pressure will build over the lake from the south. As it moves east
Monday night winds will back around to the south and eventually
southeast by Tuesday morning. Winds will increase from the west
and northwest 10 to 15 knots Wednesday as low pressure moves
across James Bay. Thursday afternoon northwest winds will increase
to 15 to 20 knots increasing further to 25 to 30 knots Thursday
night and Friday.

&&

.CLE WATCHES/WARNINGS/ADVISORIES...
OH...None.
PA...None.
MARINE...None.

&&

$$
SYNOPSIS...Oudeman
NEAR TERM...Oudeman
SHORT TERM...Oudeman
LONG TERM...TK
AVIATION...TK
MARINE...TK


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