140
FXUS61 KCLE 231331
AFDCLE

Area Forecast Discussion
National Weather Service Cleveland OH
931 AM EDT Mon Sep 23 2024

.SYNOPSIS...
A low pressure system and associated cold front will move across
the area today. Another low pressure system will move northeast
into the area for Tuesday into Wednesday. High pressure will
build from the north for Thursday.

&&

.NEAR TERM /THROUGH TUESDAY/...
9:30 AM Update...

Increased PoPs through the day today to account for wraparound
moisture across Lake Erie as the low stalls over the eastern
basin of the lake until this evening. This appears to be in
respone to increasing height over eastern Canada, so expect
scattered showers and drizzle to be around most of the day from
north central Ohio through NE Ohio and NW PA.

Previous Discussion...

Rain has departed most of the forecast period with just a patch
of rain in NW PA and then some residual showers closer to the
front in Northeast Ohio. Rain will remain possible in this
region through the day with the cold front and the approaching
surface low.

Previous Discussion...
Rain moves east across Northeast Ohio and Northwest PA this
morning ahead of a cold front. Additional rain amounts of a
tenth or two will be possible through the main frontal passage,
or about Noon. The parent surface low of the cold front spins
over southeast Lower Michigan this morning and will continue
southeast across Lake Erie and into NE OH and NW PA. Some
additional shower activity will be expected as this feature
provides some localized lift across the eastern portion of the
forecast area. Outside of the immediate vicinity of the low
today, the trend in the forecast is dry through much of tonight
as a touch of ridging will enter from the northwest and bring a
slug of slightly drier air to the area. Expecting overcast
conditions through today and tonight and temperatures are
unlikely to do much behind the cold front. Suspect that
temperatures will warm a touch with the diurnal cycle into the
low to mid 70s but it will be a clear turn to fall with
temperatures today.

All attention then turns to the next system that will approach
the region late tonight but bring the next substantial rain
chance on Tuesday. The main synoptic picture is that larger
upper trough over the Upper Midwest will catch a shortwave over
the western Great Lakes on Tuesday. This will consolidate the
energy with the main trough to support the development of a low
pressure system that will target the region. A warm front ahead
of this low will lift toward the forecast area around daybreak
on Tuesday with the surface low across southern Lower Michigan
by Tuesday evening with a cold front extending southwest. With
the warm front, expect a band of showers and perhaps some
rumbles of thunder to move through the region and have PoPs
increasing back to categorical.

The main question will then be how quickly will convection
refill in the warm sector of the system on Tuesday afternoon.
There is no question that there will be additional shower and
storm activity with the lift of the main low and upper trough
passing to the northwest on Tuesday. However, if there is a
substantial break in convection and some temperature recovery,
there could be some concern about stronger or even some severe
convection on Tuesday afternoon and evening, as there could be
an opportunity for instability to build into the region. There
will be a supportive dynamic environment for convection with
30-40 kt of 0-6 km bulk shear entering the southern portion of
the forecast area Tuesday afternoon. However, if there is
continuous rainfall across the forecast area on Tuesday,
temperatures will remain in the upper 60s to near 70 and
instability will be non-existent and there will just be more
rain and some more benign rumbles of thunder. However, if a
break materializes and mid-to-upper 70s enter the area, will be
concerned for some gusty thunderstorms. This period will need to
be monitored and some of the southern counties of the forecast
area are in Day 2 Marginal Risk of severe weather from SPC.
Total rainfall through Tuesday evening should be up to one inch.
Not expecting much in the way of flooding and the one inch is
unlikely to be a substantial drought buster, but will at least
somewhat curb the drought from enhancing across the region.

&&

.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY NIGHT/...
Shower and thunderstorm chances continue across the eastern two-
thirds of the CWA Tuesday night into Wednesday as a cold front
tracks east across the region. Any severe weather chances will
dwindle with the loss of daytime heating Tuesday night. As mentioned
in previous discussions, there will probably be a bit of a lull in
shower and thunderstorm activity Tuesday night into the first half
of Wednesday before coverage potentially increases with peak diurnal
heating/instability Wednesday afternoon. The NAM is hinting at a
surface low developing somewhere over the Ohio Valley or possibly
even the local area Wednesday. If this occurs, there could be higher
shower/thunderstorm coverage and higher PoPs for Wednesday and
Wednesday night. If this scenario does not pan out, the cold front
and showers will exit to the east by Wednesday night.

A ridge will briefly build over the area for Thursday as the mid-
week system departs to the northeast and a cutoff low drifts into
the southeastern CONUS. Dry weather is favored for the end of the
short term period.

Highs will be in the 70s Wednesday before temperatures return to the
mid 70s to lower 80s Thursday. Overnight lows will generally be in
the upper 50s to lower 60s during the period.

&&

.LONG TERM /FRIDAY THROUGH SUNDAY/...
Uncertainty still exists with the long term period as low pressure
drifts into the Tennessee Valley. Some moisture with this system may
sneak into the local area at some point late this week into the
weekend, but as of now the highest precipitation chances may remain
to the west of the area. Maintained chance PoPs in western zones
with slight chance PoPs elsewhere Friday through the weekend. The
pressure gradient may tighten north of the low Friday and northeast
winds may gust to 25 to 30 mph downwind from Lake Erie Friday
afternoon into early Friday evening.

High temperatures will be in the mid 70s to lower 80s Friday through
Sunday with lows in the upper 50s to lower 60s likely each
night.

&&

.AVIATION /12Z Monday THROUGH Friday/...
Ceilings across the region are a mix of MVFR and IFR with MVFR
largely along and west of the main front and IFR occurring
ahead of the front where rain is most recent. There will remain
this mix of non-VFR across the airspace today. Some recovery to
VFR is expected in Northwest and North Central Ohio where some
drier air will intrude along with staying away from the main low
and cold front. Areas further east should stay MVFR today with
perhaps some isolated rain showers remaining in the region. The
next system will start to approach at the end of the TAF period.
Winds will become south to southeast and rain and non-VFR will
return with likely IFR once widespread rain settles in, but that
may be after the TAF period.

Outlook...Non-VFR likely Tuesday in showers and thunderstorms
and low ceilings. Non-VFR conditions may linger through
Wednesday with residual rain and low ceilings in the region.

&&

.MARINE...
630 AM EDT Update...
Frontal passage winds are a bit higher than previously
anticipated with northwest winds of 15 to 20 knots occurring in
portions of the western basin. Have issued a Small Craft
Advisory/Beach Hazards Statement from Reno Beach to Willowick
until 18Z/2 PM EDT today. The western half of the headlines may
be allowed to drop earlier than 18Z, but it may take a couple of
hours for higher waves to subside after winds diminish.

Previous Discussion...
A cold front will cross the area today, allowing winds over the
lake to shift to the northwest and increase to 10 to 15 knots.
Flow briefly becomes light and variable tonight into early
Tuesday before southeast winds increase to 10 to 15 knots ahead
of an approaching warm front Tuesday. By Tuesday night,
southeast winds could approach 20 knots in the eastern basin of
the lake, although the highest waves will be focused into the
open/Canadian waters. Can`t rule out a brief Small Craft
Advisory from Conneaut OH to Ripley, NY if winds trend higher
due to downsloping effects. Winds diminish to 6 to 12 knots and
gradually become westerly as yet another cold front crosses the
lake Wednesday into Thursday. Winds gradually veer to the
northeast Thursday before flow deepens in response to a
tightening pressure gradient as low pressure lifts north into
the Tennessee Valley Thursday night into Friday. Depending on
the track of the low, northeast winds may approach or even
exceed 20 knots in the central basin which could result in Small
Craft Advisories in at least the central and especially western
basins.

&&

.CLE WATCHES/WARNINGS/ADVISORIES...
OH...Beach Hazards Statement until 2 PM EDT this afternoon for
     OHZ007-009>011.
PA...None.
MARINE...Small Craft Advisory until 2 PM EDT this afternoon for
     LEZ143>146.

&&

$$

SYNOPSIS...Sefcovic
NEAR TERM...Garuckas/Sefcovic
SHORT TERM...Maines
LONG TERM...Maines
AVIATION...Sefcovic
MARINE...Maines