391
FXUS61 KCLE 071102
AFDCLE

Area Forecast Discussion
National Weather Service Cleveland OH
702 AM EDT Sun Jul 7 2024

.SYNOPSIS...
High pressure will be over the Ohio Valley today then shift towards
New England on Monday. Moisture from the remnants of Beryl will
approach the area towards the middle of the week.

&&

.NEAR TERM /THROUGH MONDAY/...
A quiet forecast remains on track for today. Any patchy fog that
developed overnight will dissipate through 8-9 AM.

Previous discussion...
Surface high pressure will be overhead today then shift towards New
England on Monday. The airmass is sufficiently dry for only
scattered cumulus clouds to develop with no precipitation in the
forecast through Monday. Temperatures will trend 2 to 4 degrees
warmer today except for locations in NE Ohio and NW
Pennsylvania where lake breezes will keep areas from Cleveland
to Erie PA with similar temperatures to Saturday. Upper level
heights trend upward on Monday in response to the trough
deepening across the Upper Midwest. With surface winds out of
the south, temperatures will continue to trend warmer with highs
in the upper 80s to low 90s. Dewpoints will tend to be near or
just above 60 degrees which is typical of summer and will not
contribute to noticeable increases to the heat index.

&&

.SHORT TERM /MONDAY NIGHT THROUGH TUESDAY NIGHT/...
The middle part of the week is starting to look more interesting,
with increasing odds that the remnants of Beryl will impact the
region. Of course, details are uncertain at this point given
differences with how Beryl will interact with a longwave trough
across the central CONUS, but trends point toward tropical moisture
at least bringing greater coverage of showers and thunderstorms.

Now for a little more detail, surface high pressure over the eastern
Great Lakes Monday night will exit offshore Tuesday as a northern
stream mid/upper shortwave progresses from the Upper Midwest into
eastern Canada. This will drag a cold front into the southern Great
Lakes Tuesday, but guidance is coming into agreement that the
boundary will stall somewhere near Lake Erie as the dynamics pass
mostly north of the region. This will result in less in the way of
forcing, therefore reducing the coverage of showers and
thunderstorms compared to previous forecasts. There will be some
synoptic scale lift on the southern fringe of an 80-90 knot upper
level jet streak, and this combined with at least moderate MLCAPE of
1000-1500 J/Kg will allow scattered convection to develop in the
afternoon and evening, but not all areas will see rain. An isolated
severe storm or two is possible in this pattern, mainly in the form
of damaging downburst winds and locally heavy rainfall, since weak
mid-level lapse rates will limit hail production, but the severe
threat is not looking widespread.

Things become more interesting starting Tuesday night. As the
aforementioned shortwave moves out across eastern Canada, broad
mid/upper troughing over the central CONUS will pick up Tropical
Cyclone Beryl and lift it from the lower Mississippi Valley into the
southern or western Great Lakes by Wednesday evening. This could
spread deeper tropical moisture and anomalously high PWATs over 2
inches northeastward into the region Tuesday night and Wednesday,
but the track of the remnant circulation differs in the guidance.
The latest NAM and deterministic Canadian runs take the circulation
up through Ohio while the ECMWF takes it up through Indiana, and the
GFS takes it just east of Chicago. These differences are the result
of uncertainty regarding the amplitude of the central CONUS trough
which range from an open trough to somewhat of a closed low. The
latest QPF forecast from WPC utilizes an ensemble blend which puts
the steadiest swath of rainfall across Indiana and Michigan, but
there is still room for this to shift farther west or east in time.
Regardless, increasing moisture Tuesday night and Wednesday will
lead to greater coverage of showers and thunderstorms, so have
increasing PoPs during that period. Coverage should be greatest
during the day Wednesday as the tropical moisture interacts with
diurnal heating. It is worth noting that if the track goes across
Indiana and Michigan, enhanced low-level shear in the eastern
quadrant could result in low-topped supercells with rotation, so we
could see a marginal severe threat Wednesday in addition to locally
heavy rainfall. Coverage of precip should gradually lessen Wednesday
night as the circulation lifts away from the region.

Highs Tuesday will reach the mid/upper 80s, cooling into the low/mid
80s Wednesday, but still humid. Lows Monday night and Tuesday night
will stay in the upper 60s/low 70s, with mid/upper 60s Wednesday
night.

&&

.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
There remains some uncertainty with how the upper level pattern will
evolve late in the week into next weekend behind the remnants of
Beryl. This is due to a quasi Omega block starting to break down
allowing the broad longwave trough over the central CONUS to shift
east, but the speed in which that happens is uncertain. The
deterministic GFS is the slowest since it has more of a closed low
over the Upper Midwest compared to a more open trough axis in the
other guidance. At this time, stayed with NBM PoPs and temperatures
which has seasonably warm and humid conditions and daily chances for
scattered showers and thunderstorms as daytime heating interacts
with the old frontal boundary in the region. Once the trough lifts
out, higher heat over the Rockies and Plains could attempt to spread
east later next weekend into the following week, but some form of NW
mid/upper flow looks to persist keeping the warmest conditions west
of the region.

Highs in the upper 70s/low 80s Thursday will warm into the low/mid
80s Friday and mid/upper 80s Saturday.

&&

.AVIATION /12Z Sunday THROUGH Thursday/...
High pressure will maintain mostly clear skies today and winds
of 10 knots or less through the period. We are seeing a few
sites with MVFR visibilities at TAF issuance but these will
improve through about 1230Z. Otherwise scattered cumulus clouds
are possible this afternoon with mostly clear skies tonight.
Westerly winds today will veer to northwesterly at CLE/ERI/YNG
this afternoon with a lake breeze, then east to southeast
overnight.

Outlook...Non-VFR possible in isolated to scattered showers and
thunderstorms Tuesday through Thursday.

&&

.MARINE...
Mainly quiet conditions will continue on the lake through the
period. Light and variable winds today and Monday thanks to high
pressure over the southern Great Lakes will turn S to SW Monday
night and eventually W late Tuesday with speeds increasing to 10-15
knots as the high shifts east and a cold front sags into the region.
Winds will then oscillate between E and NE at 10-15 knots Tuesday
night and Wednesday as the remnants of Beryl approaching from the
southwest before turning W to NW by Thursday as the system exits to
the northeast.

Locally higher winds and waves could occur in and near scattered
thunderstorms Tuesday and Wednesday.

&&

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

&&

$$

SYNOPSIS...KEC
NEAR TERM...KEC
SHORT TERM...Garuckas
LONG TERM...Garuckas
AVIATION...KEC
MARINE...Garuckas