899 
FXUS61 KCLE 162021
AFDCLE

Area Forecast Discussion
National Weather Service Cleveland OH
421 PM EDT Sun Oct 16 2022

.SYNOPSIS...
A cold front will move through the area tonight as low pressure
develops over the Lake Huron region. This low pressure system
will deepen over eastern Ontario on Monday and remain over the
region through the middle of the week.

&&

.NEAR TERM /THROUGH MONDAY NIGHT/...
A cold front approaches the region from the northwest this
afternoon and will sweep across the area tonight. This front
will start with bringing a shift in winds to the west and
allowing for some wind gusts to 25 mph to start. Clouds will
begin to fill in in earnest with the front and while the front
will cool temperatures from our 60s this afternoon, clouds will
limit the initial fall with a mix of mid 30s to lower 40s across
the area. As previously stated, winds will remain elevated with
the frontal passage and do not expect frost to develop tonight.

For Monday and Monday night, an upper trough deepens
considerably across the Great Lakes region as a surface low
meanders near Lake Huron. This trough will allow for widespread
lift to allow for rain to develop across the region. The best
rain will be nearest to Lake Erie as moisture off the lake and
overhead 850 mb temperatures around minus 4 C will allow for
ample lake induced instability to allow for some robust rain
showers across the region. In addition, with the instability,
there is a good bet for some embedded thunder with the rain.
However, the main question for the rain on Monday is the exact
location and timing, which will largely depend on the speed of
the trough. The trough seems to be slowing enough to have the
initial rain to be favored over Lake Erie with southwest flow
across the lake. The trough will move through later in the
evening and finally push much of the rain on shore and have the
categorical PoPs timed across the region as appropriate. With
cooling temperatures, have some snow mixed in across the area on
Monday night. Temperatures aren't the greatest for widespread 
snow with a min of -5 C at 850 mb, but there should be a flake
or two mixing in and with some of the more intense rain off Lake
Erie, there could be some accumulating graupel. Temperatures on
Monday will struggle with cold air advection fighting the 
diurnal cycle and highs in the 40s are expected. For Monday 
night, temperatures will remain cold and much of the area will 
be in the 30s. Have a Freeze Watch for areas possible 32 and 
colder. With winds staying up, not expecting too much frost but 
it will be a freeze for several spots.

&&

.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
The deep mid/upper closed low will remain centered near Georgian Bay 
Tuesday night through Wednesday with reinforcing shortwaves dropping 
through the broad, moist, cyclonic flow around the low. This will 
continue the pattern of well below normal temps, scattered showers, 
and lake-effect rain (some snow at night).

Starting off Tuesday morning, a mid-level shortwave and associated 
surface trough will be crossing the region. Lake-effect rain and 
snow will be ongoing given strong cold air advection, 850 mb temps 
of -4 to -6 C, deep moisture, and a deeply mixed boundary layer with 
equilibrium levels up to 12,000 feet and extreme lake induced CAPE 
values over 1300 J/Kg. These factors combined with a long 240-250 
degree fetch will lead to a strong band of lake-effect precip over 
the lake. There are differences between the NAM and CMC regarding 
how fast the aforementioned shortwave/surface trough crosses the 
region, and models tend to have a south bias with moving long lake 
axis bands southward too quickly. With this in mind, feel that the 
band will be slower to move onshore across NE OH and NW PA, so 
adjusted PoPs to have the categoricals moving inland east of 
Cleveland slower Tuesday morning into the afternoon. In terms of 
precip type, all lower elevations and areas near Lake Erie should 
mainly be rain, perhaps mixing with a few wet flakes or graupel in 
the morning, but as the burst of heavier precip moves inland from 
the lake, could see some wet snow over the higher terrain areas of 
the primary snowbelt, especially in interior NW PA in the morning. 
Thunder is likely with this band given the extreme instability, so 
locally heavy rainfall is possible too from east of Cleveland across 
the primary snowbelt through NW PA. This threat of locally heavy 
rain could linger through the afternoon if the band gets hung up and 
struggles to push fully inland, which is possible given a strong 
lake aggregate thermal trough. 

Later Tuesday afternoon and Tuesday night, another shortwave and 
associated surface trough should finally veer boundary layer winds 
to 300-310 degrees allowing for more of a multi banded lake-effect 
set-up. This will end the heaviest lake-effect precip, but periods 
of showers will continue across the primary snowbelt of NE OH and NW 
PA, and even getting into parts of the secondary snowbelt, Tuesday 
evening into Wednesday morning. Wet snow will again mix in 
overnight, but little to no accumulations are expected. By Wednesday 
afternoon, the big upper low will finally begin lifting toward 
Hudson Bay with the boundary layer flow also backing ahead of 
another shortwave trough. Drier air will gradually be working in 
with inversion heights starting to lower too, but the increasing 
fetch and south shore convergence as the band lifts northward could 
bring some steadier lake-effect showers again to far NE OH and NW 
PA, so held onto likely/categorical PoPs in those areas Wednesday 
afternoon and evening. The flow will further back Wednesday night, 
so most lingering lake-effect will lift toward western NY. 

It will be a cold, raw early to mid week period with highs in the 
low/mid 40s Tuesday and mid/upper 40s Wednesday. Lows Tuesday night 
will fall into the low/upper 30s with upper 20s to low 30s 
Wednesday night.


&&

.LONG TERM /THURSDAY THROUGH SUNDAY/...
The mid/upper longwave trough over the eastern CONUS will linger 
Thursday keeping the region in chilly NW flow, but strong surface 
ridging building in from the west should end any lingering lake-
effect outside of a few stray showers in NW PA. A big pattern change 
then looks to start Friday and really take hold over the weekend as 
the trough axis lifts out allowing broad ridging from the Plains to 
build east Friday, with the mid/upper ridging then amplifying 
over the eastern CONUS Saturday and Sunday ahead of a deep, 
digging trough in the Rockies. This will support a big warm up 
and dry conditions. Highs in the upper 40s/low 50s Thursday will
warm into the upper 50s/low 60s Friday and upper 60s/low 70s 
next weekend.


&&

.AVIATION /18Z Sunday THROUGH Friday/...
A cold front approaching from the northwest this afternoon will
return clouds to the area this evening and shift winds from the
southwest to the west with its passage. Ceilings with this first
batch of clouds will fall to lower VFR range under 5 kft. As low
pressure deepens to the north, winds will increase through the 
night and into Monday and wind gusts up to 30 kts are possible 
after daybreak on Monday. As colder air settles across the
region, ceilings will begin to fall closer to MVFR levels and as
lake effect processes begin on the Great Lakes with the cold
air, ceilings will fall to MVFR and rain will begin to develop
across the region. Have begun early vicinity shower mentions at
KCLE and KERI but these will need to be refined further as rain
is expected for much of the next several days with the
meandering low pressure to the north and lake effect.

Outlook...Non-VFR with lake effect rain/snow showers across NE
OH into NW PA through Wednesday. Elsewhere scattered showers 
and low clouds could allow for some non-VFR conditions.

&&

.MARINE...
It will be a very active week on the lake as a strong cold front 
crosses tonight followed by a series of troughs through mid week. W 
to SW winds will increase to 15-25 knots late tonight, starting on 
the western basin then working into the eastern basin Monday 
morning. This will build waves to 6 to 10 feet on the central and 
eastern basins by Monday afternoon, with 3 to 6 feet in the western 
basin. These winds and waves will have staying power with WSW to W 
winds staying at 15-25 knots through Wednesday, with even over 30 
knots possible at times Monday afternoon into Monday night. Did not 
go with gales at this time, but this will be a high end small craft 
advisory Monday and Monday night, with the small craft headlines 
lingering through 12Z Wednesday morning west of Vermilion, 06Z 
Thursday from Vermilion to Geneva, and 00Z Friday from Geneva to 
Ripley. The waves will take the longest to come down on the eastern 
basin which is why the headlines goes so long there. Lighter winds 
are expected for the end of the week as high pressure builds in.

Occasional waterspouts are also possible Monday through Wednesday 
night as strong cold air advection moves across the warm lake 
waters, but stronger winds should reduce the coverage of these.


&&

.CLE WATCHES/WARNINGS/ADVISORIES...
OH...Freeze Watch from Monday evening through Tuesday morning for 
     OHZ013-014-020>023-027>033-036>038-047.
PA...Freeze Watch from Monday evening through Tuesday morning for 
     PAZ002-003.
MARINE...Small Craft Advisory from 2 AM Monday to 8 AM EDT Wednesday 
     for LEZ142>144.
     Small Craft Advisory from 4 AM Monday to 2 AM EDT Thursday for 
     LEZ145>147.
     Small Craft Advisory from 6 AM Monday to 8 PM EDT Thursday for 
     LEZ148-149.

&&

$$
SYNOPSIS...Sefcovic
NEAR TERM...Sefcovic
SHORT TERM...Garuckas
LONG TERM...Garuckas
AVIATION...Sefcovic
MARINE...Garuckas