-- Discussion containing changed information from previous version are highlighted. --
050
FXUS61 KCLE 240611
AFDCLE

Area Forecast Discussion
National Weather Service Cleveland OH
211 AM EDT Fri May 24 2024

.SYNOPSIS...
A warm front will lift north across the Ohio Valley on Friday. Low
pressure over the Upper Midwest will swing a cold front east across
the region late Friday into Saturday. Another low pressure system
out of the Great Plains will lift northeast into the Ohio Valley
region for the holiday weekend.

&&

.NEAR TERM /THROUGH TONIGHT/...
930 PM...Still monitoring a sub-severe storm in eastern Knox
County this evening, capable of producing 40-50 mph winds and
half-inch hail. This storm has showed signs of a deviant "left-
mover" and should quickly weaken as it moves north of the
instability gradient over the next hour or so. No additional
storms are expected this evening or overnight.

Previous Discussion...
High pressure gradually builds eastward overnight tonight as a warm
front begins to lift north from the lower Ohio Valley. Hi-res
guidance continues to indicate the potential for a few pop up
showers and storms later this evening across Central Ohio as a
shortwave aloft enters the region. However, dry low levels from high
pressure may inhibit the development of these showers and storms.
For now, have slight chance PoPs through late tonight along and
south of US-30 before a mid-level ridge returns for Friday.

The mid-level ridge should keep us dry through the day Friday as the
warm front continues to progress northward. The parent low pressure
system over the Upper Midwest will occlude Friday night as the warm
front lifts out of our area. The weakening low will drag a cold
front east across the region late Friday night into Saturday
bringing our next round of showers and storms. Given the timing of
the frontal passage, there is low confidence in strong to severe
storms along the front as the system will be weakening as it
reaches our area.

Overnight lows tonight remain above normal as they settle in the
upper 50s to lower 60s. Another warm day in store Friday as highs
rise into the upper 70s to low/mid 80s under a mostly sunny sky.
Warm overnight lows on Friday night in the mid 60s.

&&

.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
A cold front is expected to enter Northwest OH Saturday morning and
work across the area through the afternoon and early evening.
Guidance disagrees on whether or not remnant convection and an
associated weak shortwave will bring shower or thunder potential
Saturday morning. There is potential for this activity to dissipate
or at the least significantly weaken by early Saturday. Otherwise, a
weak shortwave, the front, and some associated jet support will
swing through late morning and into the afternoon from west to east.
Assuming morning clouds and rain aren`t more widespread, scattered
to numerous storms are favored to develop along or just ahead of the
advancing cold front during the midday and afternoon timeframe on
Saturday. There`s enough uncertainty that we have chance POPs in the
30-40% range area-wide Saturday morning, with likely wording (60-
70%) generally along and east of the I-71 corridor during the
afternoon or early evening, exiting east into Saturday night.

We are not currently outlooked for severe weather on Saturday, and a
lack of a more robust elevated mixed layer (EML), uncertainty
regarding morning cloud debris / rain potential, and modest low-mid
level flow argue against any sort of robust severe threat. However,
models that have less in the way of morning clouds or rain suggest
that stronger heating could yield 1000-2000 J/KG of MLCAPE, which
along with 20-30 knots of deep-layer shear and some mid-level dry
air could support at least a marginal severe threat with any
stronger storms that develop in the afternoon, especially along and
southeast of the I-71 corridor. This conditional severe threat will
hinge on if any convective debris is limited enough in the morning
or midday to allow for strong heating. If severe storms appear more
probable, gusty to locally damaging winds and small to marginally
severe hail would be the main concerns.

Weak high pressure will slide through and bring quiet weather
Saturday night into the first half of Sunday. A quickly amplifying
shortwave and intensifying low pressure will lift out of the Plains
and into the Great Lakes Sunday and Sunday night. This will lift a
warm front through the area Sunday afternoon or evening with a cold
front approaching from the west late Sunday night. Strong wind
fields, a large EML plume, and seasonably rich moisture will support
a robust severe threat to our west and southwest Sunday afternoon
into Sunday night. As indicated by both the Storm Prediction Center
Day 4 outlook and Colorado State machine learning severe weather
forecast guidance the greatest severe risk is solidly to our
southwest. However, given the impressive ingredients that appear
likely to be in place towards the Ohio Valley do not want to
entirely write-off the potentially locally, especially if guidance
trends more aggressive in terms of lifting the warm front north on
Sunday. Will need to monitor both the warm front Sunday afternoon
and evening and then activity spreading in from the west overnight
ahead of the cold front for shower / thunder potential, and have
POPs increasing to 60-80% area-wide by some point Sunday night.

Highs on Saturday should reach the low 80s for much of the area,
assuming convective debris is not too widespread. Lows Saturday
night will generally settle into the 50s to near 60. Highs Sunday
should again reach near or a bit better than 80, with lows Sunday
night staying up in the 60s.

&&

.LONG TERM /MONDAY THROUGH THURSDAY/...
A generally unsettled long term period is forecast as an upper
trough drifts from the Great Lakes towards the Northeast, with
various shortwaves rotating around the larger trough and bringing
potential for scattered showers and thunder. POPs are highest Monday
and Tuesday ahead of the trough axis and decrease notably by
Thursday as we finally get behind the upper trough axis and beneath
upper-level confluence. POPs will heavily depend on the timing and
track of the various shortwave, though they do have a diurnal flavor
to them with relatively higher POPs each afternoon with relatively
lower POPs at night. It will certainly not be raining the whole
first half of next week, but given the fast-moving nature of the
northwest flow most periods do require at least some sort of shower
or thunder mention until Wednesday night / Thursday. Temperatures
will be near to a bit warmer than normal on Monday, cooling to a bit
cooler than average for Wednesday and Thursday.

&&

.AVIATION /06Z Friday THROUGH Tuesday/...
-- Changed Discussion --
Primarily mid and high cloud overhead at TAF issuance is
expected to depart to the east through 12Z. As this cloud
clears, some reduced visibilities are possible for a brief
window just before sunrise. Included a couple hour tempo for
MVFR visibilities at MFD/CAK but confidence is only medium in
this occurrence. Skies will be mostly sunny through the daytime
hours with clouds arriving from west to east tonight as moisture
arrives along a pre-frontal trough. It is possible that
scattered showers or even a few thunderstorms could reach
TOL/FDY/CLE before the end of the TAF window but confidence was
not enough to include prevailing conditions.

Winds are generally light and variable through 15Z then out of
the south/southwest. CLE/ERI are expected to have a lake breeze
develop between 15-18Z. A drainage wind returns by 02Z tonight
with southeasterly winds.

Outlook...Scattered showers and storms possible Saturday
afternoon and evening. Chance of thunderstorms returns Sunday
night into Monday with non-VFR possible. Lower chances of
showers and thunderstorms linger into Tuesday.
-- End Changed Discussion --

&&

.MARINE...
Winds will vary in direction at under 15 knots through Sunday. Winds
will increase to 15-25 knots Sunday night into Monday out of the
south, shifting southwest Monday night and west-northwest Tuesday
into Wednesday. Small Craft Advisories may be needed at times Monday
through Wednesday. A few thunderstorms may reach western Lake Erie
Friday evening before dissipating. A few thunderstorms are possible
over the lake on Saturday though greater potential will be inland.
There may be greater thunderstorm potential near or over Lake Erie
late Sunday and Sunday night.

&&

.CLE WATCHES/WARNINGS/ADVISORIES...
OH...None.
PA...None.
NY...None.
MARINE...None.

&&

$$

SYNOPSIS...Iverson
NEAR TERM...Iverson/Kahn
SHORT TERM...Sullivan
LONG TERM...Sullivan
AVIATION...KEC
MARINE...Sullivan