Area Forecast Discussion
Issued by NWS Cleveland, OH

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096
FXUS61 KCLE 191505
AFDCLE

Area Forecast Discussion
National Weather Service Cleveland OH
1005 AM EST Sun Jan 19 2025

.SYNOPSIS...
A low pressure system will move northeast along a cold front up
the East Coast today. This low will help pull an Arctic cold
front across the area by tonight. Arctic high pressure will
slowly build into the region by Tuesday.

&&

.NEAR TERM /THROUGH MONDAY/...
10:00 AM Update:
A broad area of light lake effect snow is ongoing across the
Cleveland metro and surrounding areas. Radar returns are
gradually beginning to increase with this activity, with webcams
and ASOS sites suggesting some visibility drops to 2-3 miles at
times along with some very light accumulations of no more than
0.5", primarily on untreated surfaces to this point. The
immediate forecast is on track and only made a couple of minor
tweaks to match to current obs/radar.

Looking ahead, am not planning on making any changes to the cold
headlines on this shift as the advisory issued early this
morning should hold for both tonight and Monday night. As
alluded to below, Tuesday night into Wednesday morning will be
the coldest and most impactful night (with the duration adding
to infrastructure impacts by then).

Regarding the snow, the relatively most organized band at this
point stretches across parts of Cuyahoga and into Medina County.
Flow will start slowly backing soon, so should see activity
focus from Cuyahoga into Summit by midday and then gradually
pivot east across Northeast OH through the afternoon. As
synoptic moisture increases and the airmass cools this lake
effect will gradually intensity. Will need to closely evaluate
secondary snowbelt counties, as there are increasing indications
that a burst of snow with origins to Lake Michigan and decent
synoptic support from a shortwave will move near the western
lakeshore and into the Cleveland metro, northern secondary
snowbelt counties, and then the primary northeast OH snowbelt
this evening. Event total accumulations could squeak over 4"
over a 12-18 hour period in some secondary snowbelt counties,
and could squeak over 6" in an 18-24 hour period in places such
as Geauga County. No headline changes with this package, though
did make modest changes to QPF and snow ratios this evening to
bump snow up a bit in the Cleveland metro, along with places
such as Lorain County, northern Medina/Summit/Portage Counties,
and Trumbull County.

Satellite also depicts broad synoptic lift over much of the
region, with radar suggesting light snow is falling aloft but
not reaching the ground. Should see some light synoptic snow
reach the ground across the area this afternoon with modest
accumulations and impact. Greater concern will be the potential
for a fairly widespread batch of snow showers, with potential
for a few heavier snow showers or squalls, along the leading
edge of the incoming arctic air moving into much of northern
Ohio from the west later this afternoon and this evening. With
increasingly cold temperatures, these snow showers can easily
stick to roads, which along with visibility drops may lead to
travel impacts. Am planning on doing some messaging for that
potential this shift.

Previous Discussion:
The plunge into a mid-January deep freeze starts today. The
opening act will be a multifaceted snow event across the area
with a mix of traditional lake effect snow with additional snow
thanks to some synoptic features. Some light returns are already
starting to appear on the radar this morning as 850 mb
temperatures continue to crash across Lake Erie with a light
northerly flow. Right now, the bulk of the instability and
moisture is very shallow across the region within the first 4-5
kft of the atmosphere. However, as additional low level moisture
and instability off Lake Huron enter and some mid-level lift and
moisture from the southeast United States low also arrive, the
setup for lake effect snow will become better throughout the
day. This event will be intriguing from the start with the mean
flow being close to due north. This will allow for the best snow
to be around the Cleveland metro to start, especially the
eastern suburbs and will go with about an inch by Noon and
another 1-3" just after sunset. As the day progresses, some of
the synoptic features will also take aim into the region. The
southeast low will be halfway up the East Coast and the back
edge of the precipitation shield may skirt some of the southeast
portions of the forecast area. This system will also pull an
Arctic cold front across the area and there should be some snow
that develops upstream in Indiana and Michigan (with some Lake
Michigan enhancement) that will push across the entire forecast
area and could be the culprit for an inch or so of snow in the
Mansfield/Mid-Ohio region.

As this Arctic front crosses the area this evening and tonight,
winds will back to the northwest and then west, allowing for the
lake effect snow to start to pivot into far NE OH and eventually
NW PA. The most potent lake effect snow will remain tied to
wherever the Lake Huron connection sets up and that should
cascade from the eastern Cleveland suburbs up I-90 and into Erie
County, PA. However, the pivot will be quick through the night
and suspect that this connection will be into western New York
quickly on Monday morning. With that, have cropped back snow
totals just a touch and have upgraded Erie County PA from the
Winter Storm Watch to a Winter Weather Advisory. Some scattered
snow showers could continue to impact Erie County PA through
Monday, but the main focus will likely be offshore. Elsewhere,
high pressure will start building into the region and conditions
will be on a dry and clearing trend tonight into Monday.

Outside of the snow, the widely announced cold outbreak will
start tonight behind the Arctic cold front. Temperatures will
struggle today and many locations may have even already seen
their daily high in the 20s. Temperatures will fall into the
single digits or even near zero tonight, as 850 mb temperatures
continue their crash beyond the -20C value. Strong west winds
will allow for wind chill values in the double digits below
zero. High temperatures on Monday will struggle to do much with
most areas remaining in the single digits and wind chills will
remain frigid well below zero. Since wind chill values will stay
above -25F for tonight into Monday, have upgraded the Extreme
Cold Watch to a Cold Weather Advisory for the onset of this
event and through the previous watch period through Wednesday
morning. More details on the cold for Monday night through
Wednesday night is in the short term section below.

&&

.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY NIGHT/...
The coldest weather in several years is still on track to impact the
region through mid week, and that remains the main story since the
actual temperatures, wind chills, and duration will create
infrastructure and public safety concerns.

Expansive mid/upper longwave troughing covering much of the CONUS to
start the week will gradually lose amplification through Wednesday
night as the associated mid-level closed low (Polar Vortex) near
Hudson Bay slowly lifts farther northeastward. As this happens, a
broad surface high over the Tennessee and Lower Ohio Valleys Monday
night will build north into the southern Great Lakes/northern Ohio
Valley Tuesday night and Wednesday before shifting across the Mid
Atlantic region Wednesday night. This all leads to the cold weather
peaking Monday night through Tuesday night before starting to
moderate.

The 00Z NBM guidance has trended back slightly colder for the Monday
night and Tuesday timeframe after a few runs of "warming." This
makes sense given a southwesterly boundary layer flow causing the
arctic air to wrap in from the southwest, which is typical during
the strongest arctic outbreaks in our region. Did a blend of the NBM
with 5-10% of the RGEM for temperatures Monday night through
Tuesday, which gives lows of 0 to -5 F Monday night and highs of
about 3 to 8 F Tuesday. These temperatures combined with west-
southwest winds of 5-15 knots will lead to wind chills of -15 to -20
F Monday night and -10 to -15 F Tuesday. As the surface high builds
north Tuesday night and Wednesday, the clearing skies and lighter
winds still looks to support the coldest night. Continued with
actual lows of -8 to -15 F Tuesday night followed by a rebound into
the 8 to 15 F range for highs Wednesday. This will lead to wind
chills approaching -25 F early Wednesday morning, which is Extreme
Cold Warning criteria. As described in the Near Term section, the
decision was made to issue a Cold Weather Advisory for the entire
Sunday night through Wednesday morning period for the wind chills
staying closer to -15 F most of the time, but the cumulative effects
of several days of this combined with colder wind chills Tuesday
night/early Wednesday morning may necessitate a later upgrade to a
warning for Tuesday night/Wednesday morning. This will be monitored
over the next 48 hours. Subzero lows will continue Wednesday night
in far eastern Ohio and NW PA, but the airmass will be slowly
retreating at that time. See the Cold Weather Advisory for
information on impacts to infrastructure and public safety.

Other than the cold, lake-effect snows will continue Monday night
through Tuesday night before the high gradually shuts down the
activity Wednesday and Wednesday night, but the west-southwesterly
boundary layer flow will keep the main band offshore over western
NY. Only a half inch or so of snow is expected near the lakeshore of
Lake, northern Ashtabula, and Erie Counties in any 12 hour period as
occasional snow showers brush the region combined with weak
shortwave perturbations and daytime instability supporting
occasional light snow over land. Any snow will be very dry and
"dusty" given the deep arctic air mass and a DGZ near the ground,
below the best moisture and lift.

&&

.LONG TERM /THURSDAY THROUGH SATURDAY/...
As mentioned above, the worst of the arctic air will retreat by
Thursday, but northwesterly mid/upper flow will continue downstream
of very persistent mid/upper ridging near the West Coast. This will
keep the Great Lakes and Northeast U.S. in a cold and active winter
pattern. Another shortwave will drop from the northern Plains
through the Mississippi Valley Thursday. Timing of this feature and
its associated cold front remain uncertain, so held off on any light
snow until Thursday night and Friday as the trough axis passes
overhead. Behind this shortwave, there could finally be a stronger
warming trend as heights briefly rise ahead of the next trough and
blast of cold air, so have slowly warming temperatures through next
weekend.

Highs will moderate into the low/mid 20s Thursday and Friday, with
upper 20s/low 30s Saturday.

&&

.AVIATION /12Z Sunday THROUGH Thursday/...
Conditions across the region continue to be a mix of VFR and
MVFR. Conditions will be remain similar over the next several
hours until snow starts to blossom across the region. While
there will be several mechanisms helping with snow potential at
all terminals, the lake effect snow will be the most impactful
with the potential for IFR. The IFR with the lake effect should
stay east of KCLE, but all of KCAK, KYNG, and KERI are all in
play with any IFR starting toward KCAK and pivoting east to KYNG
and then KERI this afternoon and evening. Elsewhere, snow should
be limited to just MVFR impacts and the snow potential at KTOL
and KFDY remains very conditional and will maintain a PROB30
window for MVFR snow. An Arctic front will cross the area and
winds will shift from the north to northwest and then west
through the period. Winds behind the front will have gusts in
the 20-25 kt range.

Outlook...Non-VFR ceilings and visibility in snow will linger
across far NE OH and NW PA into Monday with some potential for
non-VFR to redevelop for Monday night into Tuesday.

&&

.MARINE...
N winds of 5-10 knots on the lake today will become W and increase
to 15-25 knots tonight behind an arctic cold front. Winds will then
back to WSW and increase to 20-30 knots Monday into Monday night
before decreasing to 15-25 knots Tuesday. These winds combined with
deep arctic air and water temperatures of 32 to 33 F will lead to
heavy freezing spray where water remains open in the open waters
from Avon Point to Ripley. However, expect ice to rapidly increase
through midweek, and by the time the SW winds diminish to 10-15
knots Tuesday night through Thursday, these open waters may be
mostly ice covered. The Heavy Freezing Spray Watch was upgraded to a
warning from 06Z Monday through 06Z Wednesday to account for the
coldest temperatures and strongest winds where water remains open in
the open waters from Avon Point to Ripley.

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 will arrive early Monday morning 1/20, and persist
through Wednesday 1/22. The coldest period is expected to be
late Tuesday night into early Wednesday morning with current
forecast temperatures approaching record lows for 1/22. Below
are the current record low temperatures for 1/20-22.

Date    Toledo      Mansfield    Cleveland    Akron        Youngstown    Erie
01-20   -17(1985)   -22(1985)    -18(1985)    -24(1985)    -20(1985)     -15(1985)
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 from 1 AM Monday to 10 AM EST Wednesday
     for OHZ003-006>014-017>023-027>033-036>038-047-089.
     Winter Weather Advisory until 10 AM EST Monday for OHZ011>014-
     089.
PA...Cold Weather Advisory from 1 AM Monday to 10 AM EST Wednesday
     for PAZ001>003.
     Winter Weather Advisory from 4 PM this afternoon to 4 PM EST
     Monday for PAZ001-002.
     Winter Weather Advisory from 4 PM this afternoon to 10 AM EST
     Monday for PAZ003.
MARINE...Heavy Freezing Spray Warning from 1 AM Monday to 1 AM EST
     Wednesday for LEZ166>169.

&&

$$

SYNOPSIS...Sefcovic
NEAR TERM...Sefcovic/Sullivan
SHORT TERM...Garuckas
LONG TERM...Garuckas
AVIATION...Sefcovic
MARINE...Garuckas
CLIMATE...