093 
FXUS61 KCLE 210410
AFDCLE

Area Forecast Discussion
National Weather Service Cleveland OH
1110 PM EST Mon Jan 20 2025

.SYNOPSIS...
High pressure builds through the Ohio Valley tonight. A re-
enforcing cold front crosses from west to east on Tuesday. High
pressure builds back in Tuesday night into Wednesday.

&&

.NEAR TERM /THROUGH TUESDAY NIGHT/...
1100 PM EST Update...
The band of lake effect snow over Lake Erie has shifted south a
bit more than expected which has allowed moderate snow to move 
onshore. High res guidance doesn't have the wind shifting much 
through the overnight so several inches of snow accumulation is 
possible in northern Erie County, PA, primarily from roughly 
Presque Isle State Park to North East. Moderate to periodically 
heavy snowfall in addition to blowing/drifting snow will result 
in slick travel and reduced visibilities. A Winter Weather 
Advisory has been issued through 7AM/12Z, but can't rule out 
needing to extend the advisory if the band is slow to shift 
north Tuesday morning. There may be some light snow 
accumulations from northeastern Lake County into northern 
Ashtabula County, but expect impacts to be limited.

915 PM EST Update... 
Overall, the forecast remains on track and no major changes 
were needed with this update. Temperatures across most of the 
area are in the single digits and a few spots are approaching 
zero degrees. The band of lake effect snow that is impacting 
western NY will generally stay offshore tonight, but can't rule 
out light snow periodically grazing northern Lake, Ashtabula, 
and Erie (PA) counties. 

Previous Discussion...
Lake effect snow has just about lifted offshore of Erie County,
PA and should be able to let the Winter Weather Advisory expire
at 4 PM. This snow band will sit just offshore tonight into 
early Tuesday and could graze the Erie County shoreline at 
times. Otherwise, we should be done with LES for the time being.

High pressure and the cold, dry arctic airmass will lead to a
cold but quiet and clear evening and night. Interestingly 
enough, some cumulus have developed this afternoon but will 
quickly dissipate with sunset. Lows tonight are still expected 
to generally fall to a -5 to 5 above range. It likely will be 
hard for winds to decouple tonight, though a narrow surface 
ridge axis will extend out of the Ohio Valley and towards 
central and east-central Ohio. With at least some fresh snow in 
that area, it's possible some lower-lying areas decouple and see
temperatures tank locally more than expected. Wind chills will 
generally bottom out in the -14 to -22 range tonight, which is 
solidly within the "advisory" realm. 

A shortwave and surface cold front will move across the region
from west to east on Tuesday, bringing a modest increase in
synoptic moisture and some lift to the region. Some mid-level
clouds should spread in late tonight into Tuesday morning as
PVA/height falls ahead of the shortwave and modest low to mid- 
level warm air advection/isentropic lift arrive. Some very light
snow could break out ahead of the cold front Tuesday due to the
isentropic lift. The more interesting feature will be the cold 
front itself. Decent low-level convergence, along with 
sufficient low-level moisture and steep low-level lapse rates, 
will yield potential for snow showers along and just ahead of 
the front. This forecaster was a bit amused to see forecast 
soundings depicting just a little bit of CAPE ahead of the front
on Tuesday in such a cold airmass. In response, hit most of the
area with chance (30-50%) POPs for a rather brief window from 
west to east on Tuesday. Have lower POPs (10-20%) in the Toledo 
area and actually increase to likely (60-70%) from our eastern 
couple tiers of Ohio counties into Northwest PA. Snow amounts 
will generally be less than 0.5" west of I-77, with locally up 
to an inch possible farther east. There could be a brief period 
of travel annoyances on Tuesday with any snow. While amounts are
light, it will be quite cold and any measurable snow will stick
to roads. Also, there could be a convective component along the
front, leading to brief intensity with some snow showers. Given
the cold and dry arctic airmass, most or all of the clouds and 
snow growth will take place above the preferred dendritic growth
zone on Tuesday. This will likely mean smaller flakes which 
won't have an exceptionally high snow to liquid ratio, but could
effectively reduce visibility. Highs on Tuesday will generally 
warm to a 5 to 12 degree range, with a bit of a non-diurnal 
trend possible in Northwest OH with cold air advection kicking 
in during the afternoon behind the frontal passage. Wind chills
recover a few degrees Tuesday afternoon, though will struggle to
warm above -5 to -15.

The front exits east Tuesday night with high pressure building
quickly out of the Ohio Valley, leading to a dry and mainly
clear night. Lake effect will try to briefly come back onshore 
into Erie County, PA right behind the front before lifting back
over the lake. Don't want to entirely rule out a quick inch or 
so of "dusty" snow if that happens. Otherwise, the big story 
will be the cold. Clearing skies, rather fresh snow pack across 
the eastern two-thirds of our area, a "refreshed" cold airmass 
right behind the front, and slackening pressure gradient will 
set the stage for surface temperatures to plummet Tuesday night.
Have air temperatures falling to -5 to -15 in general, slightly
warmer near the eastern lakeshore. Lighter winds will work 
against extremely cold wind chills, though it may be hard for 
winds to go completely calm. Wind chills will bottom out -20 to 25
across most of the area, and still can't rule out a potential 
need to eventually upgrade parts of the area to an Extreme Cold 
Warning (criteria is -25F). With dew points expected to drop to 
the -15 to -20 range, room is there for low-lying and less- 
urban areas to drop to near or below -20 degrees if they're able
to decouple. Hard to get this in the forecast grids, though did
lower temperatures from the prior forecast a bit, especially in
lower-lying areas where we have relatively lighter winds in the
forecast. Infrastructure issues caused by the cold will peak 
Tuesday night-early Wednesday.

&&

.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
Slowly will be coming out of the coldest air of the season for the 
area, with teens Wednesday and a significant jump Thursday back into 
the 20s with some brief low level warm air advection. 850mb 
temperatures climb into the -10C range Wednesday as the Canadian 
high pressure system that brought the cold airmass shifts east of 
the CWA and a clipper system tracks into the northern Great Lakes. 
Expecting a cold front shortly thereafter from the surface low over 
the northern lakes on Thursday bringing a few snow showers with it 
along with a weak reinforcement to the chilly air that has plagued 
the region for the month of January. The pattern is very progressive 
with that cold front off to the east very quickly and high pressure 
back into play for Thursday night. Some questions in the forecast at 
this point with the potential for lake effect behind the cold front. 
Favorable lake effect snow wind directions are not a slam dunk and 
might be a little more variable during the Thursday night period, so 
only carrying low POPs/snow amounts at this time, but will be 
something to watch going forward.

&&

.LONG TERM /FRIDAY THROUGH MONDAY/...
Pattern aloft becomes more zonal, which will allow temperatures to 
push towards the freezing mark heading into the weekend as more 
moderate air that has been pinned well to the south is allowed to 
creep back northward. No major systems on the horizon, but could see 
a couple weak troughs aloft push through in the long term period, 
largely benign. Still going to be largely below normal for 
temperatures as we head into the last week of January.

&&

.AVIATION /06Z Tuesday THROUGH Saturday/...
VFR with some mid-level clouds will persist through tonight with
ceilings lowering to low-end VFR or MVFR as a cold front moves
east across the area Tuesday. A band of lake effect snow should
remain to the north of KERI through tonight, but can't rule out
light snow periodically clipping the terminal. Snow showers 
associated with the cold front should generally remain east of a
line from KTOL/KFDY and will be relatively fast-moving. A brief
period of IFR visibilities is possible at eastern terminals, 
but confidence in snow coverage is too low to include prevailing
sub-MVFR conditions. Opted for PROB30 for reduced visibilities 
for the time being. Ceilings should improve relatively quickly 
once precipitation ends.

Winds will be out of the southwest around 6 to 12 knots tonight
with winds becoming more westerly and increasing to 10 to 15
knots with gusts to 20 to 25 knots Tuesday afternoon.

Outlook...Mainly VFR expected Tuesday night through early
Thursday. Non-VFR possible in scattered snow showers Thursday.

&&

.MARINE...
Freezing Spray in the open waters east of Avon Point continues to be 
a potential hazard through Tuesday night with southwest wind gusts 
reaching 25-35kts. The Heavy Freezing Spray Warning remains in 
effect during this period. As the lake becomes less turbulent 
through mid week and into the end of the week, continued ice 
coverage is favorable with the coldest airmass of the season 
currently in place. Mainly iced over from Vermilion west, although 
lots of ice shifting still taking place with wind direction changes. 
Winds do not come down below 15kts until Thursday.

Small Craft Advisory issuance has been suspended until further 
notice for nearshore waters from Maumee Bay to Ripley due to 
extensive ice cover.

&&

.CLIMATE...
Arctic air persists through Wednesday. The coldest temperatures
are expected late Tuesday night into early Wednesday morning 
with forecast temperatures approaching record lows for 1/22. 
Below are the current record low temperatures for 1/21-22.

Date    Toledo      Mansfield    Cleveland    Akron        Youngstown    Erie                 
01-21   -20(1984)   -19(1985)    -17(1985)    -24(1985)    -20(1985)     -16(1985)      
01-22   -12(1936)   -10(1936)    -10(1936)    -13(1936)     -9(2022)      -7(1970)

&&

.CLE WATCHES/WARNINGS/ADVISORIES...
OH...Cold Weather Advisory until 10 AM EST Wednesday for OHZ003-
     006>014-017>023-027>033-036>038-047-089.
PA...Cold Weather Advisory until 10 AM EST Wednesday for PAZ001>003.
     Winter Weather Advisory until 7 AM EST Tuesday for PAZ001.
MARINE...Heavy Freezing Spray Warning until 1 AM EST Wednesday for 
     LEZ166>169.

&&

$$

SYNOPSIS...Sullivan
NEAR TERM...Maines/Sullivan
SHORT TERM...26
LONG TERM...26
AVIATION...Maines
MARINE...26
CLIMATE...