013 
FXUS61 KCLE 060243
AFDCLE

Area Forecast Discussion
National Weather Service Cleveland OH
943 PM EST Sat Dec 5 2020

.SYNOPSIS...
A strong storm system and low pressure off the New England Coast
will move northeast into the Canadian Maritime through Sunday. 
An upper level trough will continue over the Great Lakes region
Sunday into Monday. Upper level ridging and high pressure will
build across the Ohio Valley for the middle and end of next week
with milder weather.

&&

.NEAR TERM /THROUGH SUNDAY NIGHT/...
Snow showers are really starting to struggle in Ohio as drier
air encroaches from the west. Have downgraded PoPs to isolated
in NE OH. Some scattered showers remain in NY and PA and will
keep the highest PoP values further east into NW PA. Some
clearing is approaching the Toledo area and will need to watch
for temperatures to drop where clearing persists.

Previous Discussion...
The forecast area will remain in a persistent northwest flow
regime over the next 36 hours. With some marginal cold air
advection and some shallow moisture in the lowest couple
thousand feet, some scattered lake effect snow showers will be
possible but appears largely dependent on help from an upstream
connection with Lake Huron. With that, have changed PoPs to
iso/sct coverage wording and have the area of PoPs pivoting
westward with the mean low-level flow. This pattern will
continue through Sunday and Sunday night and will keep some low
PoPs through the entire near term period. Elsewhere, expansive
cloud cover continues across the region, tapping into this low
level moisture and these clouds will remain across the region
through Sunday night. Temperatures through the period will be
well below normal meandering between the lower 30s and upper
20s.

&&

.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
An upper level trough extending from low pressure over Nova 
Scotia to the southwest will shift off the East Coast by 
Tuesday. An upper level ridge will build east into the Great 
Lakes region Tuesday and dominate the Great Lakes region during 
the latter part of this forecast period. The upper level trough 
will result in cold air advection over the local area Monday as 
cold pool settles in over the region. This air mass will begin 
to retreat to the east Tuesday with the upper level trough axis 
and warm air advection will begin to shift east. A dissipating 
weak wave of low pressure will slide southeast across the 
northern Great Lakes Monday and eventually dissipate. A quick 
shot of moisture associated with the low pressure and cold front
will slip southeast across the local area Monday morning and 
bring a quick shot for some snow shower activity. Expecting snow
accumulations to be barely a dusting in the morning. Surface 
high pressure will build east into the Ohio Valley Monday night 
and push the moisture and cold front to the east. Otherwise, 
fair weather will return for Monday night into Tuesday. 
Northwest flow will be expected after the frontal passage but 
air mass is expected to be very dry aloft so will not expect any
lake effect at this time. Cold air advection will keep 
temperatures in the 30s for highs and lows in the 20s during 
this period.

&&

.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
A large upper level ridge over the eastern United states will begin 
to amplify slightly by the end of the week as a deep digging upper 
level trough dives into the Central Plains states. Surface high 
pressure over the Ohio Valley will settle south and build as it 
moves out to the Atlantic Ocean from the Georgia coast. Warm air 
advection will take place on the west side of the high pressure into 
the forecast area for much of the latter half of the week.  As the 
upper level trough begins to dive into the Plains States toward the 
end of the week, a series of surface low pressure systems will 
develop over the Oklahoma Panhandle. The first will move northeast 
through the central Great Lakes Friday night keeping our area in the 
warm sector.  However, looking further out, the second Panhandle 
Hook appears it will track deeper south and keep the local area on 
the cold side of the low.  Another possible winter storm will need 
to be watched for Sunday as the week progresses. All of the long 
range models agree on colder air and development of this low at this 
time. Otherwise, fair weather will persist through the week until 
Thursday with the next shot of rain by Friday with the first 
Panhandle low pressure system. Temperatures will start out in the 
30s for highs Wednesday and then begin to warm back to the 40s for 
the rest of the week. Lows in the 30s.

&&

.AVIATION /00Z Sunday THROUGH Thursday/...
Ceilings are lowering across the region from VFR to MVFR as the
atmosphere cools this evening and ceilings settle below 3000 ft.
Some lake effect snow showers have developed to the lee of Lake
Erie, mainly impacting KCLE, KCAK, and KYNG. Where showers
persist, ceilings are are finding their way below 2000 ft with
some isolated IFR. Trends through the overnight will be for
ceilings to remain MVFR with ceilings continue falling to below
2000 ft in most areas. Isolated to scattered lake effect snow
showers will continue through Sunday but have no confidence to
put a mention in the TAFs beyond the next several hours. Winds
will remain out of the northwest at generally less than 10
knots.

Outlook...Non-VFR possible through Monday across northeast Ohio
and northwest Pennsylvania with scattered light lake effect 
rain/snow and clouds.

&&

.MARINE...
A small craft advisory remains in effect for northwest winds 15 to 
25 knots through this evening.  Waves have been reported around 4 
feet along the shore. Expecting winds to diminish this evening. 
Otherwise, winds will be 10 knots or less through Tuesday from the 
northwest shifting to the southwest by Wednesday and increasing to 
15 to 25 knots Wednesday night.  Although, winds are expected to 
diminish Thursday as gradient weakens under the influence of a high 
pressure ridge.

&&

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

&&

$$
SYNOPSIS...Griffin
NEAR TERM...Sefcovic
SHORT TERM...Lombardy
LONG TERM...Lombardy
AVIATION...Sefcovic
MARINE...Lombardy