259 
FXUS61 KCLE 081819
AFDCLE

Area Forecast Discussion
National Weather Service Cleveland OH
219 PM EDT Tue Jun 8 2021

.SYNOPSIS...
Surface ridge across the eastern United States will persist
through Wednesday. An upper level low will drift across the area
through the week, weakening across the area. A weak front will 
dissipate over the area on Thursday and a weak trough will
linger into the weekend.

&&

.NEAR TERM /THROUGH WEDNESDAY/...
For this afternoon, showers and thunderstorms are developing
with the diurnal cycle and with some focus along a lake breeze
boundary across far northern Ohio and NW PA. This activity is
expected to continue through the next several hours. Regarding a
severe threat, a marginal risk for severe weather has been
introduced to the eastern half of the area. Convection is
currently at a minimum in the marginal risk area; however,
instability is increasing and with dry air in the mid-levels and
increasing DCAPE, downburst potential is present across the
region and will need to be monitored for gusty winds over the
next couple of hours. As for a hydrological threat, initial
storms firing along a lake breeze boundary are quickly bursting
and setting off additional boundaries that more storms are
generating off of. This will present some training issues in
some locations and nuisance flooding could develop in some
locations. Flooding would be mostly off initial rainfall rates. 

Convection will diminish with the diurnal cycle tonight,
becoming widely scattered overnight with lingering cloud cover.
Temperatures will remain elevated with the clouds overnight and
have lows similar to last night with lows in the upper 60s/lower
70s. For Wednesday, the forecast area will go through the
motions again with a surface ridge to the southeast, allowing
for heat and moisture to build over the region and another round
of mostly diurnally driven convection. The upper low will be
closer to the region on Wednesday and suspect that thunderstorm
coverage will be higher than today and have maintained
categorical PoPs by late Wednesday afternoon. Highs should be in
the 80s, limited by convection.

&&

.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY NIGHT/...
Two different systems are expected to play a role in the weather 
during the short term period. There is one low that is expected to 
linger over IL/IN which is associated with a weak upper level 
trough. The second system located over New England is expected to 
move a cold front south across Lake Erie on Wednesday night into 
Thursday. After the frontal boundary moves south across the area, 
the aforementioned low pressure west of the area will finally begin 
to move eastward as the upper level flow becomes a bit more 
progressive. Areas of vorticity will rotate around the low pressure 
to the west of the area during the time period, which will aid in 
upper level support for showers and thunderstorms. As ample moisture 
remains over the area with a southern flow, the cold front and then 
low pressure will act as two mechanisms to shower development, with 
the greatest chance of thunderstorms during peak heating on Thursday 
and Friday. Confidence continues to grow in regards to widespread 
precipitation occurring, however there is still a bit less confidence 
in timing and location of convection. High PWAT values near 2 inches 
will be the primary concern as the atmosphere exhibits conditions 
closer to tropical in nature. This means that any showers that do 
develop will exhibit increased precipitation efficiency. With a lack 
of flow across the area, any showers/convection that develops will 
need to be monitor for the potential of flash flooding. High 
temperatures during this period will be in the low to mid 80s and 
are expected to remain humid with RH values in persisting near 80% 
during the daytime hours. This will result in temperatures feeling 
closer to 90. Overnight lows will drop into the mid to upper 60s and 
also remain humid.

&&

.LONG TERM /SATURDAY THROUGH TUESDAY/...
The trough that is expected to impact the area during the short term 
period will move off the East Coast by the beginning of the weekend. 
This will result in the area being influenced by the leading edge of 
a ridge, leaving the area under a northwesterly flow. A shortwave 
trough moving along this edge, coupled with diurnal heating may 
provide enough energy to support scattered showers and thunderstorms 
Saturday afternoon. Near the end of the long term period, models 
suggest a full pattern shift with a trough moving south across the 
area. With this, the upper level jet will also move south as it has 
been location north of the Great Lakes lately. Once this trough 
moves south, cooler temperatures can be expected along with 
precipitation. Exact timing of this is still not in agreement 
amongst models. Before the cooler temperatures reach the area 
though, temperatures are expected to remain in the low to mid 80s 
through the long term period, however there is expected to be a dip 
in dew points, which should make these warm temperatures a bit more 
enjoyable.

&&

.AVIATION /18Z Tuesday THROUGH Sunday/...
Shower and thunderstorm activity across the region will continue
through the evening hours and will be intermittent across most
of the terminals. Convection earlier this afternoon may allow
for KERI to be done with thunder chances for today and have
removed from the TAF. Elsewhere, thunder chances continue and
have vicinity thunder with tempo groups to address current
thunder timing and conditions quickly falling to IFR or lower in
heavier rain and thunderstorms. With convection waning
overnight, have dry TAFs for the middle of the TAF period and
VFR conditions. Wednesday will feature a similar thunderstorm
setup to today but perhaps with more coverage and have vicinity rain
and thunder already mentioned at the end of the TAFs. Winds
through the period will generally be light and southerly outside
of thunderstorms. A lake breeze may allow for more westerly
winds late in the TAF period at KERI and KCLE.

Outlook...Non-VFR possible Wednesday through Thursday in 
showers and thunderstorms.

&&

.MARINE...
Marine conditions are expected to remain calm as light southwesterly 
flow across Lake Erie will result in winds of 5-10 knots and waves 
below 1 foot. The only forecast concern at this point is with a cold 
front that moves south across the lake Wednesday into Thursday. 
Behind this boundary, winds are expected to shift and become 
northeasterly at 10-15 knots by Thursday afternoon and persist into 
Saturday morning. Waves are expected to build to 3-5 feet. With the 
magnitude of winds expected, lakeshore flooding across the western 
basin is not anticipated at this time. This time frame at the end of 
the week will need to be monitored for any potential marine 
headlines.

&&

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

&&

$$
SYNOPSIS...Sefcovic
NEAR TERM...Sefcovic
SHORT TERM...Campbell
LONG TERM...Campbell
AVIATION...Sefcovic
MARINE...