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687
FXUS61 KCLE 061738
AFDCLE

Area Forecast Discussion
National Weather Service Cleveland OH
138 PM EDT Thu Jun 6 2024

.SYNOPSIS...
A cold front will push through our region this afternoon. A
cooler weather pattern will develop across the Ohio Valley and
Great Lakes region for the end of this week through the weekend.
A upper level trough will develop over the Great Lakes this
weekend with temperatures below average for several days along
with some scattered lake enhanced rain showers downwind of Lake
Erie.

&&

.NEAR TERM /THROUGH FRIDAY/...
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130 PM...Diurnal cu is beginning to develop along the I-71
corridor and points east early this afternoon, lining up nicely
with a narrow corridor of deeper moisture visualized on the
split- window satellite imagery along a secondary cold front.
Could see a few isolated showers/thunderstorms along this line
of agitated cu over the next several hours before much drier air
arrives from the west, with dew points already around 50 in the
Toledo area.

Previous discussion...
We have some noticeable changes coming this way with our
weather during the next 24 to 36 hours. The weak low pressure
system and surface trough that brought us showers and storms
last night is almost our of our local area. There are some
lingering scattered showers still over far NEOH and NWPA early
this morning. Rain chances and POPs for our eastern CWA will
decrease after sunrise this morning as this system exits towards New
England later today.

Where we had rainfall overnight and wet ground, there is some
patchy fog across northern Ohio this morning. Any fog and low
stratus from overnight should burn off and mix out after sunrise
later this morning. There will be mostly sunny to partly cloudy
skies later this morning into the afternoon.

The next weather system is quickly approaching our area from
the west. There is a vigorous shortwave trough that is swirling
through the Upper Great Lakes this morning. A modest cold front
is also pushing through the central Great Lakes region early
this morning. This front will track through our area around
midday to mid afternoon. Ahead of this frontal passage, we will
see our temperatures rise back into the upper 70s to around 80
degrees. We have included a 20 to 30 percent POPs for the
potential for a few widely scattered showers and isolated
thunderstorms to possibly develop along the cold front this
afternoon. Most of the CAMs and high res near term forecast
models indicate this potential for some spotty convection trying
to develop along the front this afternoon as it moves through
NEOH and NWPA. High and mid level cloudiness will return by mid
to late this afternoon associated with this upper level system
and cold front. Gusty westerly winds will also follow behind the
frontal passage later today with gusts up to the 25 to 30 mph
possible. Any rain chances will come to and end by early to mid
evening as the front moves east of the area. A cooler and drier
airmass will start to move in behind the front and continue for
several days.

An upper level trough will dig and carve out over the Great
Lakes region starting tonight and staying around for a while
through the weekend. Most folks will notice the changes in our
weather, especially the cooler temperatures and lower humidity
by tonight and more so on Friday. With a cyclonic flow over the
Great Lakes and associated colder air aloft with this trough, we
will take a break from the summer heat and enjoy more
comfortable temperatures for several days. We will actually see
temperatures slightly below average through this weekend.

We will start in the middle to upper 50s early Friday morning
with a mix of clouds and some sunshine. Colder air aloft will
drop 850mb temperatures to around 3C or 4C on Friday which is
rather chilly for early summer. We will may start out with a
more sunshine Friday morning before we see instablilty from the
cold air aloft develop more cloud cover and a few scattered
rain showers. With Lake Erie water temps now up to 20C over the
western basin and the 850 mb forecast to be around 4C, that will
result in a lake induce CAPE or energy of around 200 J/KG by
Friday afternoon. We will likely see more lake effect clouds
downwind of Lake Erie and less clouds over towards NWOH. We will
see scattered lake effect or enhances rain showers developing
Friday, mainly impacting the Snowbelt region of NEOH and NWPA.
With the added lake induced energy and cold air instability, we
may also have a couple thunderstorms coming off the lake as
well. Winds will be breezy and at times gusty on Friday from the
west again up to 25 mph. Temperatures will only make it to the
middle 60s to up to 70 degrees.
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&&

.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY NIGHT/...
An unseasonably deep and closed-off upper low/trough will be
centered over the Great Lakes Friday evening and will gradually
drift east across Ontario, Quebec, and northern New England
through the weekend. This will keep cooler than average and
somewhat unsettled weather going through the weekend.

Friday night and a good portion of Saturday actually appear mainly
dry between embedded shortwaves working through the larger upper
trough. An exception will be far Northeast OH and Northwest PA,
where some lake effect/enhanced rain showers are expected Friday
night into early Saturday. However, guidance has trended towards
stripping away the deeper synoptic moisture a bit quicker than prior
runs so am not expecting a particularly heavy amount of lake effect
rain. A potent shortwave works through late Saturday evening into
Saturday night, bringing more widespread potential for rain showers
followed by some lake effect east-southeast of Lake Erie into Sunday
morning. Have likely POPs downwind of the lake and chance POPs
elsewhere for Saturday night...already am above blended guidance for
POPs but could see a later need for more widespread likely POPs
Saturday night as the shortwave looks potent. We`ll be back under
the core of the upper trough Sunday and there are hints at another
weak shortwave working through. Expect lake effect showers to
dwindle on Sunday as surface heating on land disrupts the lake
effect, though expect to see isolated to scattered pop-up showers
develop away from the lake. Outside of a few lake effect showers we
should dry out Sunday night. Not expecting much thunder and QPF
amounts are rather light, especially outside of the snowbelt. Could
see the combination of the synoptically forced showers with the
shortwave and following lake effect Saturday night into early Sunday
adding up to a bit more of a soaking rain in the snowbelt.

Temperatures will be on the cooler side of average through the
period, with highs generally in the 70s and lows in the 50s.
Saturday will be a bit warmer than Sunday with mid to upper 70s
expected west of the I-77 corridor, while Sunday may not quite reach
70 in far Northeast OH and Northwest PA.

&&

.LONG TERM /MONDAY THROUGH WEDNESDAY/...
The large and persistent trough over the Northeast US will gradually
lift out through the first half of next week, allowing heights to
rise substantially Monday night into Tuesday. The next shortwave
trough and an accompanying cold front begin digging into the Great
Lakes on Wednesday. Could see a few pop-up showers again on Monday
beneath the lingering upper troughing. Tuesday looks dry. Wednesday
should start dry, though low POPs begin creeping in from the west.
Temperatures will still be a bit cooler than normal for Monday but
will warm to near or a bit above normal for Tuesday and
Wednesday.

&&

.AVIATION /18Z Thursday THROUGH Tuesday/...
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VFR across the TAF sites early this afternoon with primarily VFR
to persist through the TAF period. Could see a few showers and
perhaps an isolated lightning strike over the next few hours
this afternoon at CAK/YNG, though confidence is low. Widespread
~4kft ceilings are expected to arrive later tonight into Friday
as a chilly air mass arrives across the Great Lakes, resulting
in some lake-effect clouds and perhaps scattered lake-effect
rain showers. Went with vcsh across the eastern TAF sites at
this time for Friday as confidence remains spatially low on
non- VFR TAF impacts.

Winds are generally out of the west early this afternoon, 10 to
15 knots with periodic gusts up to 20 knots possible. Winds will
slightly decrease tonight to around 10 knots before increasing
to 15 to 20 knots by Friday morning and early afternoon with
gusts of 25 to perhaps 30 knots possible at times.

Outlook...Non-VFR possible in periodic rain showers/isolated
thunderstorms on Friday. Non-VFR possible again in scattered
rain/isolated thunderstorms late Saturday into Sunday.
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&&

.MARINE...
West-southwest winds of 10-15 knots are expected behind a cold front
much of today. A secondary cold front, with a stronger push of cold
advection and flow aloft, pushes across the lake late this afternoon
into this evening. This will shift winds around to more of a due
westerly direction and increase them to 15-25 knots, especially
across the western and central basins. Winds may lull slightly in
the middle of the night tonight before coming around to the west or
slightly north of due west at 15-25 knots late tonight through
Friday evening. Winds will gradually back to a west and eventually
southwesterly direction Saturday into Saturday night and should
diminish to more of a 10-18 knot range. Winds shift northwesterly
behind a trough late Saturday night through Monday, though right now
most guidance holds winds below 20 knots for that period. Winds
should subside further Monday night into Tuesday as high pressure
slides through the region. Waves will build to 2-4 feet in the
central and eastern basins this afternoon and come up to 3-6 feet
tonight through early Saturday. Waves will likely remain in a 2-4
range late Saturday through Monday in the central and eastern
basins, with lower potential to increase to 3-5 feet if winds trend
a bit stronger than expected behind the trough Sunday-Monday. Waves
should diminish more substantially by Tuesday.

Went ahead with a Small Craft Advisory beginning late this afternoon
or evening for all of the Ohio waters. These expire from west to
east late Friday night through Saturday afternoon. The PA nearshore
waters will need an advisory as well, but with conditions likely
remaining shy of criteria through this evening didn`t want to get
the headline out there this early. Also issued a Beach Hazards
Statement in Ohio east of Vermilion, where waves should increase
enough tonight to yield a high swim risk. The expectation is that
Erie County, OH and Erie County, PA will need to be added to this
statement by later shifts as a high swim risk is likely Friday, but
with a low to moderate risk through tonight the product was not
needed yet. Ottawa County may also need consideration for
Friday.

&&

.CLE WATCHES/WARNINGS/ADVISORIES...
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OH...Beach Hazards Statement from 8 PM EDT this evening through
     Saturday morning for OHZ010-011.
     Beach Hazards Statement from 8 PM EDT this evening through
     Saturday afternoon for OHZ012-089.
PA...None.
NY...None.
MARINE...Small Craft Advisory until 4 AM EDT Saturday for LEZ142>144.
     Small Craft Advisory from 8 PM this evening to 10 AM EDT
     Saturday for LEZ145-146.
     Small Craft Advisory from 8 PM this evening to 4 PM EDT
     Saturday for LEZ147-148.
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&&

$$

SYNOPSIS...Griffin
NEAR TERM...Griffin/Kahn
SHORT TERM...Sullivan
LONG TERM...Sullivan
AVIATION...Kahn
MARINE...Sullivan