Area Forecast Discussion
Issued by NWS Cleveland, OH
FXUS61 KCLE 042332
Area Forecast Discussion
National Weather Service Cleveland OH
632 PM EST Sun Dec 4 2016
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 /UNTIL 6 AM MONDAY MORNING/...
A lot more snow is falling than forecast and have gone ahead and
made some changes to the forecast. The northern portion of the
area could see a quick inch of snow tonight with the mixed precip
or rain confined to the south. Model low level thicknesses support
this scenario. Other minor changes as well.
Previous...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 /6 AM MONDAY MORNING 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 /00Z Monday THROUGH Friday/...
Surface trough axis rotating through will bring gradually lowering
ceilings and visibilities along with some rain and snow. Low
conditions are expected to continue through the night into
tomorrow morning with gradual improvement back to VFR in the
afternoon. Winds will be 10 to 15 knots from the southeast
shifting to southwest overnight.
OUTLOOK...Non-VFR Tuesday afternoon through Friday.
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.