957
FXUS61 KCLE 061022
AFDCLE

Area Forecast Discussion
National Weather Service Cleveland OH
622 AM EDT Mon May 6 2024

.SYNOPSIS...
High pressure builds in from the north for today. A warm front
comes through Tuesday, followed by a cold front Tuesday night,
and then another low pressure system Wednesday night.

&&

.NEAR TERM /THROUGH TUESDAY/...
620 AM Update...
No major changes to the forecast this morning. Some fog in NE OH
and low stratus as well, should clear out a few hours after
sunrise. Cooler day today with high pressure building in from
the north with more 60s than 70s. Minor temperature edits in the
forecast.

Previous Discussion...
Cold front is now through the CWA and will be settling to the south
of the CWA across the Ohio Valley through much of the near term
forecast period. Surface based high pressure that has been building
over the Great Lakes will slowly drift eastward into eastern Ontario
by Tuesday morning. This will be a dry period for much of the CWA as
it does so despite upper level PVA moving in from the southwest. The
column will be too dry without much in the way of layer humidity
except in the far southern zones. POPs will creep in from the south
later today into the chance category before retreating back to the
south tonight. Meanwhile, an upper level low will eject out of the
intermountain west into the northern plains region with an
associated surface frontal system that will be occluding. This will
still be enough to push the aforementioned stalled frontal boundary
back northeastward heading into the Tuesday time frame. Back into
the warm sector and a more unstable environment, bringing a solid
potential for severe thunderstorms for Tuesday. Forecast soundings
show deep layer CAPE above the mixing layer in higher low/mid level
RH. Despite the modest flows, a wind threat arises from dry air
intrusions around 600mb and an inverted V signature in the lowest 50-
75mb of the profile. Also looking at jet entrance aloft with winds
increasing to 60-70kts above 400mb. Back to the low levels once
again, also have around 90 degrees of veering of the low level winds
that could aid in rotation. These features are more pronounced in
the western half of the CWA. The lakeshore areas will be influenced
by ENE winds off the lake which will could keep the warm front from
moving further north over the lake. Anything that fires north over
the lake will be reliant on reaching the unstable layer off the
strong surface inversion from the cold lake. Cooler readings for
forecast high temperatures today, but warmer by roughly 10-12
degrees going into Tuesday back in the warm sector with widespread
70s in the forecast.

&&

.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/...
High pressure at the surface and aloft should exit E`ward Tuesday
night as a mid/upper-level trough lingers over the north-central
U.S. and a shortwave disturbance ejects from the trough and toward
the Upper Great Lakes. This weather pattern evolution and
dissipation of a Lake Erie lake breeze early Tuesday evening will
allow the synoptic warm front to begin to sweep NE`ward from near
the southern shore of Lake Erie early Tuesday evening and exit the
rest of our CWA during the predawn hours of Wednesday morning.
Additional scattered showers and thunderstorms are expected due to
the following: Moist isentropic ascent along the upper-reaches of
the warm front and ahead of the shortwave trough axis releasing weak
to moderate elevated instability and convergence/moist ascent along
the surface warm front releasing weak to moderate boundary layer
CAPE. Organized strong to severe thunderstorms are possible given
the expected thermodynamics and moderate to strong effective bulk
shear. Overnight lows should reach the mid 50`s to lower 60`s around
daybreak Wednesday and fair weather is expected region-wide by then
as a weak surface ridge builds from the Middle MS Valley area and is
accompanied by stabilizing subsidence.

Odds favor fair weather on Wednesday as the shortwave trough drifts
E`ward across the Upper Great Lakes and the weak ridge at the
surface and aloft continues to build from the Middle MS Valley area.
Late afternoon highs should reach mainly the mid 70`s to lower 80`s
amidst a net low-level WAA regime on the synoptic scale, but
sufficient daytime heating of land surrounding ~54F Lake Erie and a
weak synoptic MSLP gradient should allow a lake breeze to develop
during the late morning through early evening. Highs are forecast to
reach the mid 60`s to lower 70`s within several miles of the lake
due to the lake breeze.

The ridge at the surface and aloft exits E`ward Wednesday night and
is followed by the mid/upper-level trough amplifying and advancing
from the north-central U.S. toward the eastern Great Lakes/Upper OH
Valley through Thursday night. At the surface, a low should move
generally E`ward across the southern Great Lakes on Thursday through
Thursday night and be followed by a lingering trough over the Great
Lakes due to expansion of relatively-warm lake-modified air as a
much colder air mass overspreads the lakes. The low track should
allow the trailing cold front to sweep E`ward across our CWA on
Thursday. Overnight lows should reach the 50`s to lower 60`s around
daybreak Thursday as net low-level WAA persists ahead of the surface
low. Eventual and net low-level CAA behind the cold front should
contribute to daytime highs reaching the 60`s to lower 70`s on
Thursday and overnight lows reaching the mid 40`s to lower 50`s by
daybreak Friday. Scattered and periodic showers and thunderstorms
are expected on Wednesday night through Thursday night due to moist
isentropic ascent ahead of the axes of shortwave disturbances and
convergence/moist ascent along the cold front releasing instability,
including elevated instability. In addition, the seeder-feeder
process and a sufficiently-cold/moist low/mid-level atmospheric
column may allow precip to become lake-enhanced over and generally
southeast of Lake Erie overnight Thursday night.

&&

.LONG TERM /THURSDAY NIGHT THROUGH SUNDAY/...
Scattered rain showers and isolated thunderstorms are possible on
Friday through Friday evening due to the combination of additional
shortwave trough axes advancing generally E`ward across our region,
the aforementioned potential for lake-enhancement of precip over and
generally southeast of Lake Erie, and the potential for self-
destructive sunshine Friday afternoon through early evening. Daytime
highs should reach only the mid 50`s to lower 60`s amidst the
unusually-cold air mass for early to mid-May. Fair weather is then
expected Saturday morning as the longwave trough aloft and embedded
shortwave disturbances exit E`ward from the eastern Great Lakes
region, as does the attendant surface trough, and a ridge and the
surface and aloft presses E`ward across our CWA and vicinity.
Overnight lows should reach the 40`s to lower 50`s around daybreak
Saturday. The ridge at the surface and aloft should exit E`ward
later Saturday through Sunday as another trough at the surface and
aloft overspreads our region from the western Great Lakes and
vicinity. Favorable forcing for ascent and thermodynamics should
support development of additional showers and thunderstorms later
Saturday through Sunday. Daily afternoon highs should reach mainly
the lower to mid 60`s this weekend. Lows should once again reach the
40`s to lower 50`s around daybreak Sunday.

&&

.AVIATION /12Z Monday THROUGH Friday/...
Overnight LIFR fog and IFR/MVFR ceilings will dissipate in the
morning hours as high pressure builds into the region leaving
the area in VFR BKN sky cover 3-5kft, coming back down to MVFR
ceilings again tonight with the approach of a warm front from
the southwest. Winds generally easterly in this environment out
ahead of the warm front less than 10kts.

Outlook...Non-VFR likely with periodic showers and thunderstorms
Tuesday.

&&

.MARINE...
Winds of about 5 to 15 knots and waves of 3 feet or less are
expected through Wednesday. Winds trend primarily NE`erly to E`erly
as a ridge builds E`ward across the eastern Great Lakes region
through tonight and then begins to exit E`ward on Tuesday as a warm
front approaches Lake Erie from the Lower and Middle OH Valley.
Winds will trend onshore during the late morning through early
evening hours of today and especially Tuesday due to the development
of a lake breeze circulation. The warm front is expected to sweep
NE`ward across Lake Erie Tuesday night and cause NE`erly to SE`erly
winds to veer to SW`erly. SW`erly winds are expected to become
variable in direction on Wednesday as a weak ridge builds from the
Middle MS Valley and another lake breeze circulation likely develops
during the late morning through early evening.

Primarily NE`erly to E`erly winds around 10 to 20 knots develop
Wednesday night and then back gradually toward NW`erly to W`erly on
Thursday through Friday as a low moves generally E`ward across the
southern Great Lakes toward southern New England and is followed by
a residual trough lingering over the Great Lakes. Waves are forecast
to mainly be 3 feet or less, but occasional 4 footers are expected,
especially on Thursday night into Friday, when a Small Craft
Advisory may be needed.

&&

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

&&

$$

SYNOPSIS...26
NEAR TERM...26
SHORT TERM...Jaszka
LONG TERM...Jaszka
AVIATION...26
MARINE...Jaszka