123
FXUS61 KCLE 150616
AFDCLE

Area Forecast Discussion
National Weather Service Cleveland OH
216 AM EDT Mon Jul 15 2024

.SYNOPSIS...
A frontal boundary will settle across the Great Lakes through
Tuesday before pushing southeast across the area as a cold front
Tuesday night into early Wednesday. High pressure will build in
from the west Wednesday night through the end of the week.

&&

.NEAR TERM /THROUGH TODAY/...
2:15 AM Update:
An MCS is approaching from the west early this morning. There is
an MCV over southern Lake Michigan pushing east, driving
stronger convection near Grand Rapids. The southern portion of
the line is diving towards the stronger instability over central
IN. This leaves some uncertainty regarding what state the MCS is
in when it pushes in from the west starting around 5 AM.
However, do think at least some showers and thunder will persist
as moderate elevated instability (1500-2500 J/KG of MUCAPE)
should remain even through the pre-dawn. Starting to see a few
showers develop across western OH ahead of the MCS along an
instability gradient that`s lifting northeast. This gradient is
acting as an effective warm front, with enhanced flow ahead of
the MCS lifting the unstable air over it. By 4 or 5 AM as this
activity ahead of the MCS lifts into Northeast OH the potential
does exist for it to grow into scattered thunderstorms. Overall
the severe risk through early this morning is pretty low. With
steep mid-level lapse rates driving 1500-2500 J/KG of MUCAPE and
a fair amount of DCAPE, can not rule out one or two stronger
cores posing a marginal hail or perhaps wind risk. However, any
severe risk would likely be brief/localized.

Previous discussion...
Scattered showers have developed across NE OH and NW PA and
ahead of an MCS that is approaching the CWA from the west. The
strongest convection associated with the MCS is following the
instability gradient and will miss the local area to the
southwest, but it`s possible that the developing convection to
the north congeals into the line and scrapes southwestern zones
that are currently in a Severe Thunderstorm Watch and a Slight
Risk for severe weather. A boundary is currently lifting
northeast across the watch area, which could serve as a focus
for convergence and convective initiation as the MCS tracks
eastward this afternoon into this evening.

Additional scattered convection may develop through early this
evening, as already evident in Lucas County. The big question
is how widespread the convection will be and how much eastern
locations destabilize over the next few hours - if
destabilization occurs, there`s potential for more widespread
and stronger thunderstorms since there will be boundaries in
place. As of now, however, there is quite a bit of CIN and
destabilization is struggling. Unfortunately, CAMs are not
handling the current situation well, so will need to rely
heavily on mesoanalysis, radar, and satellite trends and adjust
the forecast as necessary.

While the best instability will be in western zones, there will
be sufficient buoyancy and moisture for damaging winds and
heavy downpours within any thunderstorms that develop. Shear is
a bit marginal (20-30 knots) but there is just enough for a
low-end tornado and hail threat.

It`s safe to say that the forecast for overnight and through the
remainder of the near term period also remains uncertain and
will depend on how things shake out this afternoon and evening.
Another MCS will likely approach the area from the northwest
late tonight into early Monday morning with another round of
convection possible Monday night. How much each line holds
together as it crosses into the CWA will depend on instability
and any boundaries left behind from previous storms. Can`t rule
out strong to severe thunderstorms and heavy rainfall with any
storms through Monday night. A Marginal Risk for severe weather
is in place for the entire area Monday with a Slight Risk
clipping the I-75 corridor.

It will be quite warm and humid throughout the period, although
maximum temps Monday will depend on cloud cover and
precipitation. Highs may reach the upper 80s to lower 90s with
dew points in the low to mid 70s expected. Heat indices may very
briefly touch 100 degrees, but not confident enough to do a heat
headline since any cloud cover or showers/storms will result in
cooler temps/heat indices. Overnight lows will be in the lower
70s each night.

&&

.SHORT TERM /TONIGHT THROUGH WEDNESDAY NIGHT/...
Active weather pattern will continue to impact the area through the
short term period as a northwest flow pattern remains established
with areas of shortwave upper level energy advecting along the broad
upper level trough. Initially Tuesday morning, remnants of an
overnight MCS may continue to bring showers and thunderstorms to the
area, although with limited instability at that time, right now only
expecting some gusty winds and heavy rainfall. As stated a plethora
of times in previous discussions, there is a potential for this
forecast to change/evolve and will be highly dependent on how
mesoscale features develop upstream and the strength of the system
when it arrives to northern Ohio.

By Tuesday afternoon, a cold front will approach the area from the
northwest with stronger synoptic forcing arriving as well. A mid-
level shortwave and LLJ of 40-50 knots will act to enhance storm
development. High instability, increasing shear, and a very moist
airmass with dewpoints in the 70s will aid in enhancement from the
mesoscale aspect, especially by mid to late afternoon ahead of the
front. In addition to the potential for storm development, PWAT
values in excess of 2", deep warm cloud layers, and nearly parallel
storm motion to the boundary will create very heavy and efficient
rainfall. This may lead to localized flooding concerns, especially
in urban areas and where training storms develop. Maintained the
heavy rain wording for the forecast on Tuesday and Tuesday night to
account for this threat. To highlight these risks on Tuesday and
into Tuesday night, SPC has issued a Day 3 Marginal Risk for severe
weather with strong, damaging winds the greatest threat. WPC has
issued a Slight Risk ERO for the entire area.

Late Tuesday into Wednesday, models suggest the cold front moving
across the area will begin to slow. Uncertainty in how much it will
slow and overall timing remains, so opted to increase PoPs across
the eastern tier of counties throughout the day on Wednesday. Giving
the weakened environment, not thinking much will remain severe, but
opted to maintain chance thunder at this time. Overnight on
Wednesday, the front should settle to the southeast of the area,
allowing high pressure to build in, breaking the active weather
trend and allowing for dry conditions to return.

Temperatures on Tuesday will be quite warm and muggy with highs
climbing into the upper 80s to low 90s with dewpoints in the 70s.
This will result in heat index values climbing into the mid to upper
90s. As the front slow meanders southeast, overnight temperatures on
Tuesday night will be a bit milder in the northwestern counties,
dropping into the mid 60s, but elsewhere they will likely only fall
into the upper 60s to low 70s again. A cool off is expected
Wednesday when highs only climb into the low 80s during the day and
lows fall into the upper 50s to low 60s overnight.

&&

.LONG TERM /THURSDAY THROUGH SUNDAY/...
For the entire long term period, high pressure will be the dominant
driving force of weather across the region, resulting in another
prolonged period without rainfall with cooler temperatures. Highs on
Thursday and Friday will only climb into the upper 70s to low 80s,
before warming back into the mid to upper 80s for this weekend.

&&

.AVIATION /06Z Monday THROUGH Friday/...
Another TAF cycle with opportunities for showers and
thunderstorms at several terminals but with relatively low
confidence in the details. A cluster of thunderstorms stretches
from western MI to northern IN to central IL. Guidance not
handling the presentation of this well, though there has been a
bit of a weakening trend recently. Still, expect sufficient
lingering instability ahead of this cluster to encourage at
least some shower and thunder activity to spread in from the
west after 9 or 10z with some scattered activity potentially
developing ahead of it, especially from CLE and CAK points
northeast starting 9-11z. This activity may not exit ERI and
YNG until late morning or around midday, with a lull across most
of the area this afternoon and evening. Some re-development may
occur near or south of MFD, CAK and YNG this afternoon, though
odds appear to favor that activity developing a bit
south/southeast of those terminals. Another cluster of
showers/storms has a chance to spread in from the west late
tonight into early Tuesday, largely after the current TAFs.

Southwest winds 6-10 knots continue this evening and overnight.
Winds turn more southwest while increasing to 8-14 knots with
some gusts 20-25 knots this afternoon. Higher winds and gusts
will occur in any thunderstorms.

Outlook...Mainly VFR outside of occasional thunderstorms through
Tuesday evening.

&&

.MARINE...
Southwest flow of 10-15 knots is expected to persist through
Tuesday. Winds may occasionally approach 20 knots on Tuesday as a
cold front approaches from the east. Timing of the onset of these
winds remains uncertain given the overall uncertainty with the
progression of the system the next few days. With that being said,
cannot rule out a potential short fused Small Craft Advisory being
needed for Tuesday. Late Tuesday into Wednesday, a cold front will
move south of the lake, shifting winds to west-northwest at 5-10
knots behind the boundary as high pressure builds east. These winds
will persist through at least Friday before becoming more
northeasterly this weekend.

It is worth noting the potential for multiple rounds of strong to
severe storms today through Tuesday. Where these storms do develop,
strong, damaging wind gusts are the primary threat. In areas
impacted by these storms, winds and waves may locally increase and
briefly cause hazardous marine conditions.

&&

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

&&

$$

SYNOPSIS...Maines
NEAR TERM...Iverson/Maines/Sullivan
SHORT TERM...Campbell
LONG TERM...Campbell
AVIATION...Sullivan
MARINE...Campbell