Area Forecast Discussion
Issued by NWS Cleveland, OH

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FXUS61 KCLE 031747
AFDCLE

Area Forecast Discussion
National Weather Service Cleveland OH
147 PM EDT Mon Oct 3 2022

.SYNOPSIS...
Our region will be impacted by a ridge through Wednesday as the
ridge`s parent high pressure center drifts from the central Great
Lakes toward the southern Appalachians. A strong cold front should
sweep southeast across our area Thursday through Thursday night.
Behind the front, another ridge influences our region through this
weekend as the parent high pressure center moves from the northern
Great Plains toward the Tennessee Valley. However, a trough should
linger over and near the Great Lakes on Friday.

&&

.NEAR TERM /THROUGH TUESDAY/...
Main question for coverage of frost tonight will be thickness of
cirrus. Will be evaluating cloud cover and which areas may need
to have a Frost Advisory tonight.

Previous discussion...Aloft, a ridge builds slowly from the
central U.S. and western Great Lakes region as Ian`s remnant low
meanders in vicinity of VA. At the surface, a ridge continues
to affect our CWA as the core of the ridge drifts from the
central Great Lakes toward the Lower Great Lakes and vicinity.
As the ridge builds over our area, a relaxing synoptic-scale
MSLP gradient will allow mainly NE`erly surface winds to ease
today and give way to light and variable or calm surface winds
this evening through Tuesday. Upper-level frontogenetical
convergence amidst sufficient moisture between the remnant low
and building ridge should generate isolated to scattered
cirriform cloud cover over and upstream of our CWA. Of note,
isolated lake-effect stratocumuli over and generally southwest
of Lake Erie should dissipate by midday today as lake-induced
CAPE wanes further via a lowering subsidence inversion, low-
level dry air advection, and diurnal heating of surrounding land
and overlying air.

Abundant sunshine and diurnal warming of the boundary layer should
allow late afternoon highs to reach the 60`s today and the lower
60`s to lower 70`s Tuesday. As for low temperatures, those should
briefly reach the mid to upper 30`s inland from Lake Erie around
daybreak this morning, while readings in the 40`s are expected along
and very near the lakeshore due to a NE`erly onshore surface flow
from the ~63F lake. Brief and patchy frost formation remains
possible around daybreak this morning across interior portions of
north-central/northeast OH and northwest PA. The Frost Advisory
remains in effect until 9 AM EDT this morning. Mainly clear sky and
lighter or calm surface winds will likely promote greater nocturnal
cooling this evening through daybreak Tuesday morning, when lows
should easily reach the mid to upper 30`s in many locations inland
from Lake Erie. Lower 30`s are possible in the valleys of interior
northwest PA. Patchy formation of frost, radiation fog, and river
valley steam fog should occur in these areas. Another Frost Advisory
will probably be needed, especially for interior northeast OH and
northwest PA. Warmer low temperatures in the 40`s are expected along
and very near the Lake Erie shore once again.

&&

.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/...
Finally getting out of the upper level influences of the closed low
that was Ian a few days ago as it drifts southeastward to the coast
and ridging finally works in from the west. This is a main reason why
we have not been able to get into any appreciable warm air
advection, along with the lack of favorable return flows due to the
location of the surface high that will be centered over the region.
But with some continuing insolation even through we are in shorter
days, air mass modification is gradually taking place, and high
temperatures near 70 or slightly above will become more common.

The synoptic scale pattern in the short term will become more
progressive, and the ridging aloft will be replaced fairly quickly
with an open wave/trough axis Wednesday night into Thursday. This
feature will be filling/decaying and likely starved for moisture. No
appreciable POPs with this. The more significant feature is the
sharply digging trough dropping into the northern plains region from
the central portion of Canada that will deepen into a closed low
late Thursday as it moves in over the northern Great Lakes. A
strengthening surface low in response will drop a cold front rapidly
in from the northwest, which will be knocking on the door of the
northwestern zones by the end of the Thursday period.

&&

.LONG TERM /THURSDAY NIGHT THROUGH SUNDAY/...
Cold front barrels through the region late Thursday/Thursday night
with a profound change in airmass that has 850mb temperatures
dropping from around 10C ahead of the system to the minus mid
single digits over the next 24 hours. Canadian high pressure quickly
fills in behind the front back to the northwest, and while this
feature will be weakening a bit, the airmass it brings with cold air
advection will be mid fall-like. Temperatures from Thursday to
Friday max values will drop around 15-20F from the lower 70s to the
lower/mid 50s, and even some upper 40s for NW PA. With the frontal
passage, again, all indications are a moisture poor airmass, and
rain chances and amounts are going to be on the lower side.
Unidirectional low levels flows should be expected with good delta T
over the lake, and lake effect precipitation over the northeastern
CWA is a god bet for a period of time behind the front. Temperatures
probably get cold enough during the Friday night period for a few
wet snowflakes in interior NW PA. Frost is possible into the weekend
overnights, and even near freezing overnight lows are possible as
well.

&&

.AVIATION /18Z Monday THROUGH Saturday/...
High pressure with VFR conditions expected for the majority of
terminals through the TAF cycle. Some passing mid and high
cloud tonight should limit potential for fog. Did include a
TEMPO at YNG towards 12Z and may need to add to other terminals
but confidence was not sufficient at this time.

Outlook...Scattered showers with periodic non-VFR are possible
Thursday afternoon through Friday.

&&

.MARINE...
Northeasterly winds that have been persistent over the lake finally
ease Monday, becoming light and variable Tuesday under the influence
of high pressure resulting in wave heights following suit finally
coming below 1ft on Tuesday. Winds then turn southwesterly into
Wednesday ahead of a strong cold front with southwesterly/offshore
flows on the increase. Behind the cold front Thursday through the
end of the week, northwest winds 15-25kts expected along with wave
height increases as well. These winds turns to the west southwest
Saturday, gradually easing into the end of the weekend.

&&

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

&&

$$
SYNOPSIS...Jaszka
NEAR TERM...KEC/Jaszka
SHORT TERM...26
LONG TERM...26
AVIATION...KEC
MARINE...26


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