-- Discussion containing changed information from previous version are highlighted. --
309
FXUS61 KCLE 121357
AFDCLE

Area Forecast Discussion
National Weather Service Cleveland OH
957 AM EDT Sun May 12 2024

.SYNOPSIS...
High pressure briefly builds northward across the region today
but moves quickly eastward tonight. Low pressure approaches the
region from the Southern Plains late Monday as a cold front
sags southward stalling over the southern Great Lakes.

&&

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

The forecast remains on track this morning with no changes
needed. The clouds over NE Ohio and NW PA will gradually erode
late this morning and this afternoon as high pressure and drier
air builds eastward. This will lead to all areas seeing sunshine
by late afternoon, although high cirrus will start to spread
back in this evening as a weak cold front sags in from the NW.

Previous Discussion...

Minimal changes made to the forecast. Only change was to use
coverage terms across NW PA for the morning showers. The zones
will say isolated to scattered showers through the morning.

Previous Discussion...
The lake will contribute some additional moisture and low level
lift with steeper low level lapse rates this morning. Water
surface temperatures to 850 mb temperatures are running 10+
degrees so expect the lake enhanced showers to persist into at
least late morning across NE OH into NW PA.

Beyond the morning hours we should see high pressure ridge into
the area from the south with dry conditions expected everywhere
through midnight. After midnight a cold front will be sagging
toward the north shore of Lake Erie with increased chances of
showers along and ahead of it. Most of these showers initially
remain over the lake but will attempt to move onshore across
extreme NE OH into NW PA by sunrise Monday.

Cloud cover will be slow to erode across NE OH into NW PA
today, which will impact high temperatures. Expect to see a
range of highs from around 60 across NW PA to the mid 70`s
across NW OH. A bit warmer tonight with an increasing southerly
wind and clouds increasing over the lake into NW PA. Lows should
range from the mid 40`s to mid 50`s.

A weakening cold front attempts to move onto Lake Erie by late
in the day. There may be a few showers across the east end of
the lake into maybe NW PA. The best chances likely occur across
NW OH during the evening with low chances for thunder as well.
A warm front will be north of the entire region on Monday with
highs ranging from the mid 70`s to lower 80`s.
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&&

.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY NIGHT/...
During the short term period, 2 separate low pressure system will
impact the area, resulting in multiple rounds of precipitation.
Initially, a cold front associated with a low pressure system over
Quebec will move east across the area Monday night, increasing the
chances of precipitation from northwest to southeast. A few rumbles
of thunder cannot be ruled out. On Tuesday, an upper level trough
and associated low pressure over the central US will begin to move
east across the Ohio River Valley. This system will have better
synoptic forcing with it, but with the area remaining on the cold
side of the low expecting primarily rain. The caveat may be Tuesday
afternoon where diurnal instability may result in thunder across the
area. Throughout the day on Wednesday, showers will taper from west
to east and eventually dry out Wednesday night as the aforementioned
low pushes off the Mid-Atlantic Coast and high pressure begins to
build into the area. Highs on Tuesday and Wednesday will be a bit
cooler behind the front with temperatures only rising into the mid
to upper 60s, possibly touching 70 across the southern counties.
Overnight lows will gradually cool through the period with lows
Monday night falling into the upper 50s but cooling to be in the
upper 40s to low 50s by Wednesday night.

&&

.LONG TERM /THURSDAY THROUGH SATURDAY/...
High pressure and an associated upper level ridge will allow for the
start of the long term period to remain dry and warm with temperatures
on Thursday climbing into the low to mid 70s. After Thursday, models
suggest a negative trough pushing east over the region as another
surface low develops over the Midwest. Models are fairly consistent
with that surface low tracking northeast through Ohio which likely
brings widespread showers and probably a few thunderstorms to the
area for the end of the week/beginning of the weekend, but with
divergence in model agreement on timing opted to maintain chance
PoPs for the end of the week with the greatest chance of thunder
on Friday and Saturday in the afternoon. With the area expected
to be in the warm sector of the aforementioned low at some point,
temperatures on Friday and Saturday are expected to be above normal
for this time of year with overnight lows lingering in the 50s.

&&

.AVIATION /12Z Sunday THROUGH Thursday/...
Isolated/scattered showers will remain across NW PA through the
morning. MVFR ceilings across NE OH into NW PA will gradually
decrease and lift through mid afternoon, lingering longest
across inland NW PA. Elsewhere, away from the showers, expect to
see VFR conditions continue.

We will need to monitor a cold front that sags southward to
southern Ontario tonight. Showers and lower ceilings may impact
NW PA after 08Z MON.

West to northwest winds gradually decrease through mid morning
with the highest speeds near the lakeshore. Speeds of 6-15 knots
are anticipated with gusts around 25 knots near the lake. Winds
shift to the south through the afternoon but should be under 6
knots. The southerly winds increase after 03Z MON with 6-12
knots expected.

Outlook...Non-VFR possible in showers Monday through Wednesday.

&&

.MARINE...
A surface trough lingers over the eastern Great Lakes as a low
pressure system continues to shift east this morning. As a result,
winds remain at 15-20 knots from the northwest which has allowed
waves to climb to 3-5 feet across the central and eastern basins. As
a result, the Small Craft Advisory remains in effect. As high
pressure builds in today, winds will weaken and become variable at 5-
10 knots before a warm front lifts north tonight and shifts winds to
become south-southwesterly at 15-20 knots. With predominately offshore
flow, the largest waves will remain across the northern lakeshore,
but will need to monitor wind speeds for any additional marine headlines.
Late Monday into Tuesday, a low pressure system will begin to move
east across the Ohio River Valley gradually shifting winds counterclockwise
before becoming sustained from the northeast at 5-10 knots Tuesday
night which will persist through Wednesday. High pressure returns
to the area Wednesday night into Thursday.

&&

.CLE WATCHES/WARNINGS/ADVISORIES...
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OH...None.
PA...None.
NY...None.
MARINE...Small Craft Advisory until 10 AM EDT this morning for
     LEZ145>148.
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&&

$$

SYNOPSIS...MM
NEAR TERM...Garuckas/MM
SHORT TERM...Campbell
LONG TERM...Campbell
AVIATION...MM
MARINE...Campbell