589
FXUS61 KCLE 010203
AFDCLE

Area Forecast Discussion
National Weather Service Cleveland OH
1003 PM EDT Sun Jun 30 2024

.SYNOPSIS...
A high pressure system coming down from southern Canada will
build over the Great Lakes and Ohio Valley tonight through
Monday. A warm front will lift north across the area Tuesday as
high pressure moves east of the region. A cold front will
approach the area for Wednesday afternoon and move through
Wednesday night. This front will likely stall out over the Ohio
Valley on Thursday.

&&

.NEAR TERM /THROUGH TUESDAY/...
Clouds have been making good progress clearing from the north
with some residual lake effect clouds filling in behind it. The
trend should be for clouds to eventually clear overnight with
increasing subsidence and drier air overspreading Lake Erie.
The forecast remains on track with a much cooler night in the
50s.

Previous discussion...
Our weather will be very nice and quiet this evening through
Monday night. If you have been outside today, you likely noticed
the big change in airmass compared to just 24 hours ago. A large
high pressure system is coming down from southern Canada and
slowly building over the Great Lakes and Ohio Valley this
evening. This high pressure will bring a refreshing break from
the summer heat and humidity this evening through Monday night.

Because of the cooler airmass at the surface and aloft, we are
seeing lake effect clouds coming off of Lake Erie and have been
more concentrated in our Snowbelt region of NEOH and NWPA.
Outside of the area, there is sunshine with a few fair weather
clouds over NWOH and down along the Highway 30 corridor into
central Ohio. Under the cloud cover this afternoon, it has felt
a little fall-like with temperatures stuck in the low to mid
60s. Areas that saw more sunshine today, have recovered back to
the lower and mid 70s.

The gusty northerly flow this afternoon will gradually relax as
wind speeds will taper off to 10 mph or less later this evening
and overnight. The lake effect cloud cover will also slowly
decrease and scattered out late this evening into the overnight.
Eventually all locations will have mostly clear skies by sunrise
Monday morning. Tonight`s weather will be perfect to give the
air conditioning a break and open up the windows for some fresh
air. Overnight temperatures will be rather cool with low to mid
50s expected. There could be a few spots that drop down to the
upper 40s if the skies clear out quicker and the winds can calm
down sooner.

Monday and the first day of July looks absolutely fantastic.
The center of high pressure will be just just north of Lake Erie
as it slowly moves eastward through the Great Lakes region. We
will all see plenty of sunshine and blue skies on Monday. Winds
will become northeaster 5 to 10 mph. After a cool start in the
50s, temperatures will max out in the lower to middle 70s. We
will have one more cool and comfortable night Monday night with
temperatures dropping back down in to the lower and mid 50s.
Enjoy this lower humidity and nicer weather while you can
because the warmer temps and mugginess will start coming back
on Tuesday.

&&

.SHORT TERM /TUESDAY NIGHT THROUGH WEDNESDAY NIGHT/...
Surface high pressure will be departing to the east Tuesday and
Tuesday night as upper level heights rise, allowing for
temperatures and dew points to begin creeping back up. Expect
highs to warm well into the 80s for Tuesday with lows struggling
to dip much below the mid 60s to lower 70s Tuesday night amid
continued warm air advection. Dry weather is expected for
Tuesday and Tuesday night with some mid and high-level clouds
drifting through at times.

A shortwave will slide through the northern Great Lakes on the
periphery of upper-level ridging Wednesday into Wednesday evening,
pushing a cold front and the next rain chance in from the northwest
Wednesday afternoon and evening. This cold front will attempt to sag
through Wednesday night, though with the shortwave only glancing our
region as ridging remains over the southern U.S. there is
uncertainty regarding how quickly the front can push through.

Regarding rain/thunderstorm potential, forcing with the sagging
front will not be all that strong as the better jet support will
stay to our north. However, the front is expected to begin pushing
in near peak heating on Wednesday. With dew points warming to near
or over 70 and high temperatures on either side of 90, moderate and
uncapped instability will develop Wednesday afternoon despite the
relatively poor mid-level lapse rates expected to be in place. This
should allow scattered convection to develop, with well-mixed low-
levels and moderate (30-40 knots) of deep-layer shear supporting
organized convection with decent cold pools. Despite the weak
forcing, have chance POPs near Toledo increasing to likely (60-70%)
across the rest of our area Wednesday afternoon and evening as it
seems likely that more of the area sees measurable rain than not.
However, with the relatively weak forcing expect rain amounts to be
highly variable with parts of the area continuing to miss out,
meaning any drought relief will be hit or miss. The very moist
environment, sagging/slow-moving nature of the front, and deep-layer
flow nearly paralleling the front will support a localized training
convection and heavy rain risk, though again am not expecting a
particularly widespread coverage of heavy rain amounts. At least
some potential for severe weather (mainly in the form of strong to
damaging winds) will also likely exist, though details on that will
be honed much better as we get closer. Drier weather will try
returning from the north/northwest Wednesday night, though the front
may not entirely clear our southern counties.

It will be unpleasantly hot and humid on Wednesday as strong heating
of a very moist air mass leads to highs in the upper 80s/lower 90s
with dew points reaching or exceeding 70. Heat index values are
currently forecast to remain just shy of advisory criteria (100F)
though mid to upper 90s seem like a solid bet, especially along and
west of the I-77 corridor. Lows will struggle to fall much below the
upper 60s or lower 70s Wednesday night.

&&

.LONG TERM /THURSDAY THROUGH SUNDAY/...
A somewhat unsettled pattern is expected through the long term as we
settle into westerly flow aloft on the northern edge of a flattening
ridge over the southeastern US. Confidence in timing and coverage of
showers and thunderstorms is relatively low this far out. We should
see a relative lull to start Thursday assuming the prior front
pushes far enough south. However, the front will return north as a
warm front later Thursday or Thursday night, quickly bringing a
humid and more unstable airmass back into the local area. Because of
this, much of the area has at least a slight chance or chance of
rain mentioned Thursday, with chance POPs expanding north Thursday
night. A larger trough will approach on Friday and move into the
region on Saturday, pushing a cold front through late Friday night
or Saturday from west to east. Expect a period of higher shower and
storm chances ahead of this cold front Friday afternoon and evening,
and perhaps again on Saturday from eastern OH into PA depending on
if the front is able to clear or not. If the front doesn`t yet clear
by Saturday there`s greater confidence it`ll clear out by Sunday,
allowing drier and somewhat cooler weather to move in.

&&

.AVIATION /00Z Monday THROUGH Friday/...
MVFR clouds continue across NE Ohio and NW Pennsylvania
terminals within a cool northwest flow and with enhancement off
Lake Erie. The back edge of the cloud deck will approach
Cleveland towards 01Z but will take a few hours to reach CAK/YNG
and ERI. Once clouds scatter out, VFR conditions are expected
for the rest of the TAF period. North winds remain breezy with
gusts 20 knots at 00Z but gusts should drop off quickly except
downwind of Lake Erie where it may take a couple hours.
Otherwise winds will remain out of the north to northeast
through the period. Winds will increase some again after 14Z
Monday into the 8-14 knot range.

Outlook...Non-VFR possible in showers and thunderstorms
Wednesday and Thursday.

&&

.MARINE...
Northwest winds this afternoon will shift north-northeast this
evening, with speeds of 15 to 20 knots (briefly over 20 knots this
evening) common. This will build waves sufficiently to warrant Small
Craft Advisory conditions along with an accompanying high risk for
rip currents from Lorain County points northeast through tonight.
Also added Erie County and the adjacent nearshore waters to the
headline, as the winds are expected to gain enough easterly
component this evening to build higher waves that far west. As high
pressure builds in late tonight into Monday morning winds and waves
will gradually improve, allowing the headlines to come down by 12z/8
AM Monday. Generally tranquil conditions are then expected through
Tuesday night. Southerly winds will become brisk ahead of an
approaching cold front late Tuesday night into Wednesday, with
speeds potentially reaching 20 knots for a time. The offshore nature
of the flow makes the need for a Small Craft Advisory uncertain,
though if the wind forecast trends stronger it is possible one will
be needed for a relatively brief window. Conditions are expected to
be relatively tranquil Wednesday night through the end of the week.

Thunderstorms are possible over the lake Wednesday afternoon and
evening. Additional occasional thunderstorm chances are possible
over the waters Thursday night through Saturday.

&&

.CLE WATCHES/WARNINGS/ADVISORIES...
OH...Beach Hazards Statement until 8 AM EDT Monday for OHZ009>012-
     089.
PA...Beach Hazards Statement until 8 AM EDT Monday for PAZ001.
NY...None.
MARINE...Small Craft Advisory until 8 AM EDT Monday for LEZ144>149.

&&

$$

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