CLE issues Area Forecast Discussion (AFD) at Jan 11, 4:06 PM EST
407
FXUS61 KCLE 112106
AFDCLE
Area Forecast Discussion
National Weather Service Cleveland OH
406 PM EST Sat Jan 11 2025
.SYNOPSIS...
Brief high pressure tonight and Sunday is followed by a cold
front Sunday night. Cold Canadian high pressure drops
temperatures again for early next week.
&&
.NEAR TERM /THROUGH SUNDAY NIGHT/...
Expecting a little bit of lingering lake enhanced snow showers for
the northeastern zones rough the evening hours. Expected to be off
and on in nature, and modest accumulations, generally around an inch
and a half or so. High pressure influences from the south push into
the CWA, changing the wind directions to southwesterly tonight ahead
of an organizing Alberta Clipper over the northern plains region. A
touch of warm air advection into Sunday with the brief southerly
flow and 850mb temperatures up to -4C ahead of a cold front. The
surface low for the clipper system will not make it down into the
southern Great Lakes, staying around the northern sections. This
will cause some frontolytic action for the cold front portion that
would be set to come through the CWA Sunday night. With this
issuance, going with some chance to likely POPs, low QPF overall,
and expecting only light coatings of snow generally an inch or less.
Looking at the forecast soundings, the depth of saturation is not
going to get into the prime dendritic growth zone, and may even have
some trouble getting into the -8C range. Not going to plaster the
grids with chances of freezing drizzle with the snow, but if the
depth shrinks in upcoming model runs along with the temperatures in
the saturated portion of the column getting any warmer, it is going
to need to be a strong consideration.
Temperatures could creep above freezing in a few locations Sunday by
a degree or two, the first time this has happened in quite a while
except for the Toledo area which is pushing the mid 30s today. The
cold front Sunday night will begin the reinforcements of colder air
for the short term forecast period.
&&
.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
Cyclonic W'erly to NW'erly flow aloft and embedded shortwave troughs
are expected to impact the Great Lakes and Upper OH Valley through
this period. The strongest of the shortwave disturbances is expected
to sweep SE'ward through our region on Tuesday. At the surface, a
strong cold front is expected to essentially bisect our CWA from
west to east at daybreak Monday morning. The E'ward-moving front is
expected to exit the rest of our region by the early afternoon.
Behind the front, a trough lingers over the Great Lakes and
vicinity, including our CWA, through Tuesday night. A chilly air
mass ahead of Monday's cold front passage will be followed by a much
colder air mass advancing from the Upper Midwest and vicinity
through Tuesday night. Daytime highs are expected to reach the lower
20's to lower 30's on Monday and be followed by overnight lows in
the 5F to 15F range around daybreak Tuesday morning, when minimum
wind chills near -5F to -10F are forecast. On Tuesday, afternoon
highs are expected to reach the lower teens to lower 20's and be
followed by overnight lows in the roughly 5F to 15F range around
daybreak Wednesday morning, when minimum wind chills are expected to
be near 5F to -5F in NW PA and mainly 0F to -10F in northern OH.
Outside of expected lake-effect snow (see discussion below for
details), scattered snow showers are expected along the cold front
on Monday as low-level convergence/moist ascent along the front
release at least weak potential instability in the lowest 1 km AGL.
Based on model sounding analysis, expect these snow showers to be
heavy at times as moderate to strong ascent is maximized at a cloud
temperature of ~-6C, below cloud top temperatures of -10C or
slightly colder. Additional general snow showers are expected
overnight Monday night through Tuesday evening courtesy of moist
isentropic ascent preceding the strongest shortwave trough axis and
the potential for low-level convergence/moist ascent along the
attendant surface trough axis to release weak potential instability
in the lowest 1 km AGL. As for LES, expect LES to develop over and
generally east-northeast of Lake Erie by early Monday afternoon and
continue through Monday night as cyclonic W'erly to WSW'erly mean
low-level flow remains sufficiently-moist and CAA behind the cold
front allows 850 mb temperatures to cool to near -12C over ~1C Lake
Erie by midday Monday and then to near -20C by daybreak Tuesday. The
bulk of LES is expected to target portions of WNY, but frictional
surface convergence should allow periods of LES to impact the
lakeshore and vicinity from far-northeastern Cuyahoga County to Erie
County, PA. The LES will likely be steady to heavy at times as
moderate to strong ascent is maximized in a cloudy DGZ at least 0.5
km thick. LES is expected to shift gradually S'ward and SW'ward into
the primary snowbelt and eventually the secondary snowbelt as well
on Tuesday through Tuesday night as mean low-level flow moistens
while veering gradually to W'erly and then to NW'erly.
Simultaneously, a more singular LES band is expected to evolve into
multiple bands due, in part to a decrease in fetch. The LES will
likely be steady to heavy at times as 850 mb temperatures hover near
-15C to -20C and moderate to strong ascent will likely remain
maximized in a cloudy DGZ at least 0.5 km thick.
During Monday through Tuesday night, the latest forecast calls for
fresh snow accumulations to total 6-12" in the most-persistent LES
in far-northern Ashtabula County and Erie County, PA. Lesser snow
accumulations are forecast elsewhere (e.g. 3-6" in the rest of the
primary snowbelt of NE OH and NW PA). Considered issuing a Winter
Storm Watch for parts of the snowbelt, but forecast confidence in
LES placement and amounts remains not particularly high.
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
Primarily cyclonic and mainly W'erly to NW'erly flow aloft is
expected to impact our region on Wednesday through Thursday evening.
Simultaneously, net surface troughing is expected to persist
over/near the Great Lakes, including our CWA. On Friday, a ridge at
the surface and aloft is expected to build from the west. This
pattern will be accompanied by net low-level WAA, albeit weak.
Accordingly, daytime highs are expected to moderate from near 15F to
25F on Wednesday to mainly the lower to mid 30's on Friday.
Overnight lows are expected to be near 5F to 15F around daybreak
Thursday and the mid teens to lower 20's around daybreak Friday.
Periodic snow showers are possible Wednesday through Thursday
evening in association with the aforementioned shortwave
disturbance. LES is expected to persist over/downwind of Lake Erie
and weaken gradually as lake-induced CAPE wanes via net low-level
dry air advection and eventual lowering of the subsidence inversion
that will accompany the aforementioned ridge. The LES is expected to
stream generally SE'ward from Lake Erie on Wednesday and then stream
generally E'ward and then ENE'ward from the Lake on Wednesday night
into Thursday as mean low-level flow of sufficiently-cold air backs
gradually from NW'erly to WSW'erly. The LES is expected to finally
end Thursday evening as lake-induced CAPE wanes further due to the
aforementioned processes. Additional/impactful LES accumulations are
possible. Fair weather is forecast region-wide the rest of Thursday
night through Friday as stabilizing subsidence accompanies the
aforementioned ridge.
The ridge at the surface and aloft is expected to exit E'ward Friday
night through Saturday as a trough at the surface and aloft
overspreads our region from the west. Scattered showers, in the form
of snow or a rain/snow mix, are expected as moist isentropic ascent
precedes the trough axis aloft and low-level convergence/moist
ascent accompany a cold front poised to sweep E'ward through our
area on Saturday. Overnight lows are expected to reach mainly the
20's around daybreak Saturday. Daytime highs are expected to reach
mainly the lower to mid 30's, ahead of Saturday's cold front
passage.
&&
.AVIATION /18Z Saturday THROUGH Thursday/...
Overall improving conditions, albeit slowly for the eastern
terminals where some IFR ceilings are still holding on with
light snow as well. Snow should exit over the next couple of
hours concurrent with ceilings lifting to MVFR, then IFR into
the tonight period as high pressure influences build into the
region. Expecting mainly VFR for the second half of the TAFs,
except for CAK/YNG. Models bringing in low ceilings/fog late
tonight, with CAK possibly LIFR at FL003 and 1/2SM in fog for a
few hours. YNG only slated for IFR ceilings for now. Southerly
winds on the increase for the western terminals after 15Z
Sunday.
Outlook... Non-VFR may return in snow from a clipper system on
Monday into Tuesday and persist in lake effect snow through
Wednesday.
&&
.MARINE...
A trough lingers over Lake Erie before a ridge builds from the
western Great Lakes tonight. Accordingly, W'erly winds around 5 to
15 knots back gradually to SW'erly to S'erly as waves remain 3 feet
or less. However, occasional 4 footers are possible in ice-free
waters of the central basin through this early evening. These
conditions preclude the need for a Small Craft Advisory.
On Sunday, the ridge begins to exit E'ward and is followed by a west-
to-east cold front passage on Monday as a low moves from the Upper
Midwest toward southwestern QC. S'erly to SW'erly winds as strong as
15 to 25 knots, strongest over open waters, will veer to W'erly on
Monday in response to the cold front passage. Ahead of the front,
waves trend 3 feet or less in nearshore U.S. waters and 3 to 6 feet
in open U.S. waters. Behind the front, waves as large as 3 to 6
feet, accompanied by occasional 7 to 8 footers, are expected in the
central and eastern basins. A Small Craft Advisory will be needed.
Behind the cold front, winds are expected to vary between SW'erly
and WNW'erly as a trough lingers over Lake Erie Monday night through
Wednesday. These winds are expected to be around 15 to 25 knots
Monday night through Tuesday night, when waves as large as 4 to 9
feet are expected in the central and eastern basins. On Wednesday,
winds are forecast to ease to 10 to 20 knots and allow waves to
subside slowly to 3 to 5 feet. Another ridge is expected to build
from the western Great Lakes this Wednesday night and continue to
impact Lake Erie through Thursday. Accordingly, winds are expected
to vary between SW'erly and W'erly around 15 to 25 knots. Waves are
expected to rebuild to around 5 to 9 feet in ice-free waters of the
central and eastern basins. The western basin will likely remain
primarily ice-covered through this Thursday.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...None.
PA...None.
MARINE...None.
&&
$$
SYNOPSIS...26
NEAR TERM...26
SHORT TERM...Jaszka
LONG TERM...Jaszka
AVIATION...26
MARINE...Jaszka
Source: CLE issues Area Forecast Discussion (AFD) at Jan 11, 4:06 PM EST (https://mesonet.agron.iastate.edu/p.php?pid=202501112106-KCLE-FXUS61-AFDCLE)
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