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103
FXUS61 KCLE 150109
AFDCLE

Area Forecast Discussion
National Weather Service Cleveland OH
909 PM EDT Tue May 14 2024

.SYNOPSIS...
A cold front will gradually shift southeast late this evening
into tonight as a low pressure system moves east across the
Ohio River Valley. High pressure returns on Thursday before a
warm front lifts north on Friday, followed by a cold front
Friday night into Saturday. High pressure builds back in on
Sunday and Monday.

&&

.NEAR TERM /THROUGH WEDNESDAY NIGHT/...
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905 PM Update...
Showers with a south to north moving PVA axis continue this
evening over the western CWA. Patchy mid level f-gen will
produce more showers going forward through the overnight,
scattered and slightly disorganized as the surface low pivots
west to east along the Ohio Valley. Lingering surface troughs
will also provide a focus for shower development as well. Minor
temperature adjustments, and increased the POPs in the western
zones accordingly.

Previous Discussion...
An upper-level low located over the mid-Mississippi Valley this
evening gradually moves east tonight and tomorrow across the
Ohio Valley. At the surface, a stationary front lingers from
northern Indiana to southeast Michigan and southern Ontario.
This front extends from a low over southern Illinois. This low
is expected to move east across the Ohio Valley, bringing the
stationary front southeastward as a cold front tonight and
tomorrow.

This will result in isolated to scattered rain showers through
tonight and tomorrow. There is a very low chance for a
thunderstorm or two. This afternoon, it`s most likely in
Northwest Ohio, late tonight it`s more likely in central Ohio. PoPs
are generally in the 20-40% range, except this evening and
tonight along the southern and western fringes of our forecast
area (e.g. I-75 corridor in Northwest Ohio and parts of central
Ohio) where PoPs of 60-70% are forecast. Precipitation chances
increase out east (east of I-77) Wednesday afternoon, with
isolated/scattered thunderstorms possible. High pressure builds
in by Wednesday night.
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&&

.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
Thursday will see briefly drier conditions as the broad, closed off
mid/upper shortwave trough moves into the Mid Atlantic region
allowing mid/upper shortwave ridging to slide across the Ohio Valley
and southern Great Lakes along with weak surface high pressure
ridging down from the north. Most areas will be dry outside of a few
widely scattered showers and thunderstorms in far eastern Ohio and
NW PA where lingering moisture combines with diurnal heating. Again,
coverage will be spotty.

The drier weather will be short lived as another mid/upper shortwave
trough progresses from the Upper Midwest Thursday night through the
central and eastern Great Lakes Friday and Friday night. The
associated surface low over the Upper Midwest Thursday night will
lift up into the vicinity of James Bay by early Saturday, dragging a
cold front through the area Friday night into Saturday morning.
Warm/moist advection and isentropic ascent will drive increasing
chances for showers from west to east Thursday night into Friday
morning as a warm front lifts across the region, and there looks to
be a couple hundred joules of elevated CAPE for some embedded
thunder. However, not all areas will see rain since forcing will be
weak since the mid/upper shortwave will be deamplifying as it
progresses through the Great Lakes leading to the surface low also
weakening. This will limit the strength of the low-level jet to
around 20 knots which therefore limits the strength of the moist,
isentropic ascent. For these reasons, kept PoPs at chance late
Thursday night and Friday morning. The better chances for rain will
come Friday evening and Friday night as the trailing cold front
crosses the region and forcing from the right entrance region of a
60-70 knot H3 jet supports decent frontogenetic forcing. This
combined with weak to moderate instability will bring a broken line
of showers and thunderstorms across the region, so have likely PoPs
Friday evening into Friday night. Wind fields do not look very
impressive since the wave is deamplifying and shifting farther
north, but good low-level moisture advection in the warm sector
Friday afternoon and evening (dew points rising into the low/mid
60s) could support over 1000 joules of SBCAPE if there are enough
breaks in the clouds, so isolated strong to severe thunderstorms are
possible. The main concern would be strong winds and hail. Again,
the threat is conditional. The showers/storms will gradually
progress off to the east and southeast Friday night.

Highs in the low/mid 70s Thursday will warm into the 75 to 80 degree
range Friday. Lows Thursday night will cool into the mid 50s/low 60s
with upper 50s/low 60s Friday night.

&&

.LONG TERM /SATURDAY THROUGH TUESDAY/...
The extended forecast continues to look unsettled. The
aforementioned cold front Saturday morning will become quasi-
stationary then try to press north Sunday before wavering back and
forth early next week, and possibly through the middle of next week.
This is in response to gradually deepening mid/upper troughing over
the western CONUS which builds broad/flat downstream ridging over
the central and eastern CONUS. The polar jet/westerlies look to
retreat to the US/Canadian border and northern Great Lakes by early
next week, with disturbances ejecting out of the western trough and
rippling through this flow and their associated surface waves riding
along the boundary. This pattern points to possible MCS activity
generating over the Midwest and moving into the Great Lakes at
times, as well as general scattered showers and thunderstorms near
the frontal zone, so kept chance PoPs this weekend through early
next week. Uncertainty on where the frontal boundary will be each
day, as well as the degree of forcing with each wave, makes precip
timing and coverage low confidence, so temperatures are also subject
to change, but for now, stayed with the idea of warmer/humid
conditions, but the higher heat will remain south of the CWA. This
yields low/mid 70s Saturday warming into the upper 70s/low 80s
Sunday through Tuesday.

&&

.AVIATION /00Z Wednesday THROUGH Sunday/...
MVFR ceilings will continue to push northward through the
remainder of the evening and into the overnight period. Some
scattered showers around, but only expecting MVFR to prevail
with some reduced visibilities. Places that do not receive
rainfall also could drop to MVFR visibilities as winds drop to
5kts or less. As low pressure passes south of the area west to
east along the Ohio River Valley, lingering forcing to the north
will continue the chances for showers through the remainder of
the TAF. For most terminals and times, prevailing is not
warranted and will leave the mention out for now. Easterly winds
become northerly through the TAF period.

Outlook...Non-VFR possible showers and thunderstorms Thursday
night through Saturday.

&&

.MARINE...
Winds and waves look mostly low impact through the period. NE winds
increase to 10-15 knots tonight, with some pockets of 15-20 knots in
the central and western basins, as low pressure moves through the
Ohio Valley. This will generate 2 to 3 foot waves. At this time,
think winds and waves will stay below Small Craft Advisory criteria.
NE winds will continue to average 10-15 knots Wednesday before
becoming N to NE and decreasing to 5-10 knots Wednesday night and
Thursday. Winds will turn S to SE at 5-10 knots Thursday night and
Friday as a warm front lifts across the lake, with S winds then
continuing at 5-10 knots Friday night and Saturday before turning
more E Saturday night and Sunday. A few thunderstorms could bring
locally higher winds and waves Friday evening and Friday night.

&&

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

&&

$$

SYNOPSIS...Saunders
NEAR TERM...26/Saunders
SHORT TERM...Garuckas
LONG TERM...Garuckas
AVIATION...26
MARINE...Garuckas