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fxus61 kcle 070626 
afdcle

Area forecast discussion
National Weather Service Cleveland Ohio
126 am EST Sat Dec 7 2019

Synopsis...
high pressure will build east over the local area by Saturday
morning and move east of the area by Saturday night. A warm front
will move northeast across the region Saturday. A cold front
will move southeast to just north of the local area by Monday
morning and become nearly stationary. Low pressure will move
northeast along the stationary front through the central Great
Lakes region. A trailing cold front will move east across the
local area Monday night. Meanwhile, a weak low pressure system
will develop over the central Great Lakes and move northeast
Wednesday. High pressure will build east into the Ohio Valley by
Wednesday night.

&&

Near term /through tonight/...
most of our near-term forecast remains valid. However, adjusted
Saturday morning low temperatures downward slightly across
essentially the western-third of our County Warning Area. Here, mainly clear to
partly cloudy skies and light surface winds should promote
efficient radiational cooling and perhaps patchy fog development
through daybreak Saturday. This change to low temperatures also
required an adjustment to hourly temperatures and dew points through
Saturday morning. Any fog that manages to form should disappear by
late morning.

A northwesterly low-level flow of cold air is continuing to
direct multiple bands of lake effect precip across much of the
snowbelt in our County Warning Area. Adjusted pops to have at least a slight
chance mention of lake effect precip across much of the
northeast Ohio snowbelt and all of the northwest PA snowbelt
through this evening. Any lingering lake effect precip should
then be focused across the northwest PA snowbelt early Saturday
morning. This lingering precip is still expected to end by
daybreak Saturday due to a building high pressure ridge causing
already limited lake-induced cape to wane.

Light lake effect snow may change to light freezing rain in
northwest PA after midnight tonight and before lake effect precip
ends altogether. This is due to the potential for the lake effect
cloud layer to become too shallow and warm to support ice
nucleation. Any snow accumulations are forecast to be less than an
inch, while any ice accumulations should be no more than a hundredth
of an inch. Road temperatures are above 32f and may remain above
that value through most or all of this lake effect event. Thus, have
refrained from issuing a Winter Weather Advisory since there is much
uncertainty as to whether any icing will occur along roadways in
northwest PA. This is something that will continue to be watched
closely.

Previous discussion...an upper level trough will dig into the
eastern United States tonight and Saturday as a ridge of high
pressure moves east toward the area. The ridge will move quickly
east to the eastern Seaboard Saturday night. Surface high
pressure will move east into the Ohio Valley by Saturday morning
and keep a northwest flow of cold air advection into the local
area overnight. The combination of the cold air advection and
flow will result in some lake effect rain/snow showers overnight
that will gradually diminish as flow weakens and becomes
variable. 850 mb temperatures will drop to between -6 c and -8 c
overnight. Lake to 850 mb temperatures produce conditional
instability overnight. Precipitation threat will be limited as
inversion hovers between 4000 and 5000 feet overnight. Center of
the high pressure will move east of the area tomorrow and this
will bring a return southerly flow to the region and cut-off any
lingering lake effect threat.

A large swath of clearing continues to push south across the area at
this time. Fewer clouds were present over the western half of the
forecast area due to lack of lake influence. East half still seeing
lingering lake induced cloud cover. As the night progresses, cloud
cover should gradually diminish overnight. Fair weather will
prevail across the entire forecast area tomorrow and tomorrow night
under the high pressure.

Temperatures will drop into the lower to middle 20s across the area
tonight in the cold air advection with highs recovering to the
middle 30s tomorrow. Slightly warmer temperatures expected Saturday
night in the return southerly flow.

&&

Short term /Sunday through Monday night/...
the short term begins Sunday with high pressure from the mid
Atlantic to New England. Low pressure will be moving east across
James Bay. A cold front will extend southwest into the northern
plains. This cold front will be the main weather maker towards the
end of the short term. The front will hang up in the Central Lakes
Monday as a wave of low pressure develops along the front in the mid
Mississippi Valley. By Monday afternoon the low will be moving
northeast across the Central Lakes. The cold front will track east
across the east early Tuesday. Expect rain to develop ahead of the
low Sunday night with rain continuing Monday and Monday night.
Tuesday, colder air will sweep east into the area behind the front
likely resulting in steady or falling temps through the afternoon.
Also expect rain to change to snow from the west during the day
although any snowfall amounts will be light as the colder air will
also be drier. The only exception of course will be developing lake
effect snow during the late afternoon. Highs Sunday mid and upper
40s. Highs Monday lower 50s. Highs Tuesday mid 30s west to lower
40s east...possibly before dawn.

&&

Long term /Tuesday through Friday/...
the long term begins Tuesday night with developing lake effect
across across northeast Ohio and nwrn PA. This far out, there is
some question as to how much of the area will be affected as Tuesday
night winds back taking any bands offshore. Wednesday winds veer
northwest as instability to the lake becomes extreme. At this time,
synoptic moisture appears sufficient so early Wednesday into
afternoon would be favored. Wednesday evening and night drier air
moves in from the west as high pressure builds backing winds and
ending the event. The remainder of the area will not have much
weather however temperatures will be sharply lower for all with
highs Wednesday in the low to mid 20s and Thursday in the mid to
upper 20s. Friday will have highs bounce into the upper 30s.

&&

Aviation /06z Saturday through Wednesday/...
fairly quiet taf period as high pressure builds in from the west
tonight into the daytime hours on Saturday. Northerly flow over
the lake ahead of the high is allowing for some Lower Lake
effect clouds over NE Ohio and northwest PA. Ceilings will remain VFR
across the region but clouds will be low VFR under 5000 ft
overnight, especially around Keri, kyng, and kcle. High pressure
moves overhead during the day on Saturday and will scatter out
these Lower Lake clouds. Winds will back around to the south
during the day with just some nuisance high clouds over the
region. VFR will persist well into Sunday.

Outlook...non-VFR likely late Sunday through Monday night with
rain. Non-VFR expected across the snowbelt on Tuesday into
Wednesday with lake effect precipitation. Most of this precip
should fall as snow.

&&

Marine...
will continue with the Small Craft Advisory as is. Winds are just
under criteria but as expected, the northwest fetch has build waves
to 4 to 6 feet in the nearshore waters. Winds will be diminishing
slowly this evening allowing waves to drop back under 4 feet
overnight. Otherwise winds will turn light Saturday as high
pressure crosses the area. Saturday night winds will turn southerly
and increase to 10 to 15 knots as the high moves east. Sunday, and
Sunday night, expect 15 to 20 knots from the south as the high moves
east as a cold front moves through the Central Lakes. Low pressure
will develop on the front Monday and reach the Central Lakes Monday
night keeping winds out of the south to southwest. A cold front
associated with the low will sweep east across the lake late Monday
night and early Tuesday bringing in sharply colder air and west
winds around 20 knots. West flow will continue Tuesday night and
Wednesday at 20 to 25 knots.

&&

Cle watches/warnings/advisories...
Ohio...none.
PA...none.
Marine...Small Craft Advisory until 4 am EST early this morning for
lez146>149.

&&

$$
Synopsis...Lombardy
near term...jaszka/Lombardy

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