Special Weather Statement, NWS Cleveland, OH

Area Forecast Discussion
National Weather Service Cleveland OH
223 PM EDT Tue Jun 29 2021

.SYNOPSIS...
A front will remain stalled to the north of Lake Erie today and
Wednesday before a cold front moves southeast across the area
Thursday into Friday. A trough may linger over the region into
Saturday, but high pressure could begin to build in from the
north by the end of the weekend.

&&

.NEAR TERM /THROUGH WEDNESDAY/...
Cumulus field is increasing across the region early this
afternoon and the first hints of convective initiation are
occurring along the lake breeze in Lake County and another area
area is developing over Marion County, as central Ohio begins
reaching their convective temperatures in the upper 80s. Shower
and thunderstorm coverage will continue to increase this
afternoon and evening and have maintained PoPs up to likely
across the area. Severe potential still exists with primarily a
damaging wind threat with strong low level lapse rates, high
DCAPE values, and forecast soundings across the region showing
an inverted-V signature typical of downbursts. The only question
is if convection can become strong enough before bursting as
minimal wind shear across the region will prohibit an organized
severe threat and therefore just a marginal risk from SPC.
Flooding remains a concern today as well with slow moving and
efficient thunderstorms expected across the region. Precipitable
water values to 2 inches remain across the region, supporting
heavy rainfall. Flooding is probably limited to heavy intensity
combined with urban issues and the cities of the region will be
the main concern through the evening.

Previous Discussion...
The first half of the near term period will be characterized by
a frontal boundary to the north and northwest of Lake Erie and
a broad area of high pressure across the Northeast and Mid-
Atlantic. Diurnal forcing will trigger scattered showers and
thunderstorms across the entire area this afternoon into this
evening. MLCAPE values will climb to 2000-2500 J/kg during peak
heating, although deep shear values will be quite weak at 15 to
20 knots across the majority of the area so expect storms to be
rather disorganized. Despite the lack of organization, isolated
to widely scattered strong to severe wet downbursts will be
possible given the increased instability and low to mid-level
moisture. SPC placed NW OH in a marginal risk for severe weather
today, which seems reasonable since the wind field may be a bit
more favorable in that area due to the closer proximity to the
aforementioned front. In addition to gusty winds, lack of
steering flow may produce a threat for heavy rain and localized
flooding. Scattered showers and thunderstorms may linger into
the overnight hours, but overall coverage and intensity should
wane after sunset.

The stagnant synoptic setup will finally come to an end
Wednesday as an upper-level trough begins to dig south into the
Upper Great Lakes and pushes a cold front southeast towards the
CWA. Although the airmass will remain largely unchanged (MLCAPE
values of 1500-2000 J/kg and unusually high PWAT values of
1.5-2.0 inches), the trough will provide stronger forcing and
more upper-level support with deep shear values increasing to 30
to 35 knots. This will lead to a chance of more organized
convection late Wednesday morning into Wednesday afternoon with
damaging wind gusts being the primary threat. The best chance of
strong storms will be along and east of I-71, which is
highlighted an a Day 2 marginal risk for severe weather.
Southwesterly flow parallel to the front may introduce a threat
for training storms and localized flooding.

Hot and humid weather will continue over the next couple of
days, with highs in the upper 80s to lower 90s today and
somewhat cooler low to mid 80s on Wednesday. Heat indices will
creep into the mid to upper 90s this afternoon and could very
briefly touch 100 degrees if temperatures manage to over-perform,
but don't expect Heat Advisory criteria to be met at this time.
There won't be too much relief from the heat overnight tonight,
with lows falling into the low to mid 70s and dew points
refusing to budge from the upper 60s to lower 70s.

&&

.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY NIGHT/...
An upper level trough will be digging across the Great Lakes region.
A stationary frontal boundary will be located across the region mid
week which will continue to be the focus area for scattered showers
and isolated thunderstorms. The mid level support and trough digging
across the Great Lakes region on Thursday will help give the frontal
boundary a pushing southward through the region. We will see another
good chance of scattered showers and isolated thunderstorms on
Thursday. We will see a gradual decrease in rain chances from north
to south Thursday night as the main focus area shifts southward with
the frontal boundary. By Friday,the model guidance has come into
better agreement of a mid level trough becoming into a cut off low
over the eastern Great Lakes region. This weather pattern setup
would bring scattered rain shower chances and more cloudy
conditions. Temperatures will also be cooler in the 70s for the end
of the week.

&&

.LONG TERM /SATURDAY THROUGH TUESDAY/...
The model guidance show a cut off low pressure system between the
Upper Ohio River Valley and the Chesapeake Bay region on Saturday.
This is a slight change from previous guidance. We will keep
scattered showers possible on Saturday with the better chances over
the eastern CWA. The guidance does show this low pressure system
moving slowly towards the East Coast or New England region by
Sunday. We will scattered showers moving east of the area by Sunday
and little more sunshine than clouds. Temperatures will still be
comfortable in the 70s to near 80 this weekend. Upper level ridging
will be building to our West across the Midwest by early next week
which means temperatures will be slowly climbing back upward by
Monday and sunnier conditions.

&&

.AVIATION /18Z Tuesday THROUGH Sunday/...
Cumulus field and shower and thunderstorm activity is expanding
across the region this afternoon as convection is beginning to
tap into the warm, moist air mass. The most troublesome area in
the near term will be along the lake breeze as convection
develops in NE OH and NW PA. Have TS in the TAFs for KERI and
KCLE at TAF issuance and will continue these over the next
several hours with vsby in moderate rain being the main concern
but some MVFR ceilings could briefly enter. Elsewhere, TS
chances are a bit more of a wild card but have at least a
vicinity mention for now. With current coverage trends, believe
that KTOL, KFDY, and KMFD could have a thunderstorm at the
terminal. Storms should diminish with the loss of diurnal
heating and have trends improving later this evening. Storms
over lower Michigan this evening will progress east across the
lake and could retain as some showers overnight at KERI have a
vicinity shower mention there. The warm moist air mass will
continue into Wednesday and another round of showers and
thunderstorms in the afternoon will exist and have more vicinity
thunder mentioned late in the TAF period. Winds will be
generally south across the region with west to northwest winds
behind the lake breeze this afternoon.

Outlook...Periods of non-VFR possible with several rounds of
scattered showers and thunderstorms Wednesday through Friday.

&&

.MARINE...
Light south to southwesterly winds around 5 to 10 knots will persist
through Thursday morning. Some increased flow near 15 knots may be
possible Wednesday afternoon before decreasing back around 10 knots
by Wednesday night into Thursday. On Thursday, a cold front will
move across the lake. The frontal passage will eventually bring
northerly flow 10 to 15 knots by Thursday night. Wave heights should
be limited or on the lower side do the off shore flow of winds.
Brief higher and erratic winds can be possible around any stronger
storms over the lake this week. Slightly higher waves will be
possible by the end of the week with a northerly flow off the
lake.

&&

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

&&

SYNOPSIS...Maines
NEAR TERM...Maines/Sefcovic
SHORT TERM...Griffin
LONG TERM...Griffin
AVIATION...Sefcovic
MARINE...Griffin

Hazardous Weather Outlook
National Weather Service Cleveland OH
350 AM EDT Tue Jun 29 2021

LEZ061-142>149-162>169-300800-
Ripley to Buffalo NY extending from 5NM off shoreline to US-
Canadian border-Maumee Bay to Reno Beach OH-
Reno Beach to The Islands OH-The Islands to Vermilion OH-
Vermilion to Avon Point OH-Avon Point to Willowick OH-
Willowick to Geneva-on-the Lake OH-Geneva-on-the-Lake to Conneaut OH-
Conneaut OH to Ripley NY-
Detroit River Lt. to Maumee Bay OH to Reno Beach OH beyond 5NM
offshoreline to US-Canadian border-
Reno Beach to The Islands OH beyond 5NM off shoreline to US-
Canadian border-
The Islands to Vermilion OH beyond 5 nm off shoreline to US-
Canadian border-
Vermilion to Avon Point OH beyond 5 nm off shoreline to US-
Canadian border-
Avon Point to Willowick OH beyond 5 nm off shoreline to US-
Canadian border-Willowick to Geneva-on-the-
Lake OH beyond 5NM off shoreline to US-Canadian border-Geneva-on-the-
Lake to Conneaut OH beyond 5 nm off shoreline to US-Canadian border-
Conneaut OH to Ripley NY beyond 5 nm off shoreline to US-
Canadian border-
350 AM EDT Tue Jun 29 2021

This Hazardous Weather Outlook is for Lake Erie.

.DAY ONE...Today and tonight.

No hazardous weather is expected at this time.

.DAYS TWO THROUGH SEVEN...Wednesday through Monday.

No hazardous weather is expected at this time.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is not expected at this time.

OHZ003-006>014-017>023-027>033-036>038-047-089-PAZ001>003-300800-
Lucas-Wood-Ottawa-Sandusky-Erie-Lorain-Cuyahoga-Lake-Geauga-
Ashtabula Inland-Hancock-Seneca-Huron-Medina-Summit-Portage-Trumbull-
Wyandot-Crawford-Richland-Ashland-Wayne-Stark-Mahoning-Marion-Morrow-
Holmes-Knox-Ashtabula Lakeshore-Northern Erie-Southern Erie-
350 AM EDT Tue Jun 29 2021

This Hazardous Weather Outlook is for north central Ohio, northeast
Ohio, northwest Ohio and northwest Pennsylvania.

.DAY ONE...Today and tonight.

There is a marginal risk for isolated to widely scattered strong to
severe thunderstorms today, with the best chance west of I-71. The
primary threat will be damaging winds. Heavy rain and localized
flooding will be possible within any thunderstorms that develop
today.

High temperatures will be in the upper 80s to lower 90s today. The
warm temperatures combined with a humid airmass will lead to heat
indices in the mid to upper 90s this afternoon.

.DAYS TWO THROUGH SEVEN...Wednesday through Monday.

There is a marginal risk for isolated to widely scattered strong to
severe thunderstorms on Wednesday, with the best chance along and
east of I-71. The primary threat will be damaging winds. Heavy rain and localized
localized flooding will be possible within any thunderstorms that
develop.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is not expected at this time.

Special Weather Statement
National Weather Service Cleveland OH
230 PM EDT Tue Jun 29 2021

OHZ012>014-089-291915-
Geauga-Lake-Ashtabula Lakeshore-Ashtabula Inland-
230 PM EDT Tue Jun 29 2021

...A STRONG THUNDERSTORM WILL AFFECT NORTHEASTERN GEAUGA...
SOUTHEASTERN LAKE AND WESTERN ASHTABULA COUNTIES...

At 230 PM EDT, a strong thunderstorm was located near Perry, or 8
miles northeast of Chardon, moving east at 20 mph.

Winds in excess of 40 mph are possible with this storm.

Locations impacted include...
Painesville, Ashtabula, Chardon, Mentor, Geneva, Madison, Perry,
Kirtland, Austinburg, Montville, Hartsgrove, Roaming Shores,
Thompson, Kirtland Hills, Rock Creek and Aquilla.

Torrential rainfall is also occurring with this storm, and may cause
localized flooding. Do not drive your vehicle through flooded
roadways.

LAT...LON 4154 8125 4161 8136 4174 8122 4190 8080
      4158 8066
TIME...MOT...LOC 1830Z 261DEG 18KT 4167 8111

Kahn

Special Weather Statement
National Weather Service Cleveland OH
247 PM EDT Tue Jun 29 2021

OHZ009-019-291930-
Huron-Erie-
247 PM EDT Tue Jun 29 2021

...A STRONG THUNDERSTORM WILL AFFECT NORTHWESTERN HURON AND ERIE
COUNTIES...

At 247 PM EDT, a strong thunderstorm was located near Norwalk, moving
northeast at 20 mph.

Winds in excess of 40 mph and pea size hail are possible with this
storm.

Locations impacted include...
Sandusky, Norwalk, Western Vermilion, Milan, Northern Milan,
Monroeville, Berlin Heights, Bloomingville, Sandusky South and
Fairview Lanes.

LAT...LON 4147 8266 4148 8269 4146 8270 4145 8266
      4144 8266 4138 8250 4143 8236 4111 8264
      4119 8284 4121 8284 4149 8269
TIME...MOT...LOC 1847Z 206DEG 18KT 4122 8271

Kahn

Special Weather Statement
National Weather Service Cleveland OH
251 PM EDT Tue Jun 29 2021

OHZ027-028-291915-
Crawford-Wyandot-
251 PM EDT Tue Jun 29 2021

...A STRONG THUNDERSTORM WILL AFFECT EAST CENTRAL WYANDOT AND
NORTHWESTERN CRAWFORD COUNTIES...

At 251 PM EDT, a strong thunderstorm was located near Sycamore, or 8
miles northwest of Bucyrus, moving northeast at 10 mph.

Wind gusts up to 50 mph and pea size hail are possible with this
storm.

Locations impacted include...
Benton, Nevada and Oceola.

Torrential rainfall is also occurring with this storm, and may cause
localized flooding. Do not drive your vehicle through flooded
roadways.

Frequent cloud to ground lightning is occurring with this storm.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.

LAT...LON 4079 8315 4086 8321 4098 8305 4086 8289
TIME...MOT...LOC 1851Z 236DEG 11KT 4086 8311

Jaszka

Special Weather Statement
National Weather Service Cleveland OH
308 PM EDT Tue Jun 29 2021

OHZ011-013-021-022-292000-
Summit-Geauga-Portage-Cuyahoga-
308 PM EDT Tue Jun 29 2021

...A STRONG THUNDERSTORM WILL AFFECT NORTHWESTERN PORTAGE...
SOUTHWESTERN GEAUGA...SOUTHEASTERN CUYAHOGA AND NORTHERN SUMMIT
COUNTIES...

At 308 PM EDT, a strong thunderstorm was located near Parma, or 9
miles south of Cleveland, moving east at 15 mph.

Winds in excess of 40 mph are possible with this storm.

Locations impacted include...
Cleveland, Parma, North Royalton, Solon, Hudson, Twinsburg,
Streetsboro, Warrensville Heights, Macedonia, South Russell, Highland
Hills, Garfield Heights, Maple Heights, Broadview Heights, Aurora,
Brecksville, Bedford, Beachwood, Seven Hills and Bedford Heights.

Torrential rainfall is also occurring with this storm, and may cause
localized flooding. Do not drive your vehicle through flooded
roadways.

LAT...LON 4151 8125 4121 8125 4126 8169 4128 8169
      4128 8173 4142 8170
TIME...MOT...LOC 1908Z 270DEG 15KT 4135 8162

Kahn

Special Weather Statement
National Weather Service Cleveland OH
322 PM EDT Tue Jun 29 2021

OHZ010-011-020-292015-
Medina-Lorain-Cuyahoga-
322 PM EDT Tue Jun 29 2021

...A STRONG THUNDERSTORM WILL AFFECT SOUTHWESTERN CUYAHOGA...
NORTHWESTERN MEDINA AND CENTRAL LORAIN COUNTIES...

At 322 PM EDT, a strong thunderstorm was located near Grafton, or 7
miles south of Elyria, moving northeast at 10 mph.

Wind gusts up to 50 mph and pea size hail are possible with this
storm.

Locations impacted include...
Elyria, Strongsville, Brunswick, Westlake, North Ridgeville, Grafton,
North Olmsted, Avon, Berea, Olmsted Falls, Eaton, Oberlin, Lagrange,
Penfield, South Amherst, Pittsfield, Valley City and Eaton Estates.

Torrential rainfall is also occurring with this storm, and may cause
localized flooding. Do not drive your vehicle through flooded
roadways.

LAT...LON 4115 8218 4131 8229 4148 8195 4124 8180
TIME...MOT...LOC 1922Z 244DEG 10KT 4127 8215

Kahn

Special Weather Statement
National Weather Service Cleveland OH
327 PM EDT Tue Jun 29 2021

OHZ018-019-027-028-292015-
Crawford-Seneca-Huron-Wyandot-
327 PM EDT Tue Jun 29 2021

...A STRONG THUNDERSTORM WILL AFFECT SOUTHWESTERN HURON...
SOUTHEASTERN SENECA...SOUTHEASTERN WYANDOT AND NORTHWESTERN CRAWFORD
COUNTIES...

At 327 PM EDT, a strong thunderstorm was located near Bucyrus, moving
northeast at 25 mph.

Winds in excess of 40 mph and pea size hail are possible with this
storm.

Locations impacted include...
Bucyrus, Upper Sandusky, Willard, Plymouth, New Washington,
Bloomville, Chatfield, Attica, Benton, Nevada, Oceola and Sulpher
Springs.

Torrential rainfall is also occurring with this storm, and may cause
localized flooding. Do not drive your vehicle through flooded
roadways.

LAT...LON 4074 8319 4083 8323 4122 8290 4106 8262
      4099 8270 4099 8273 4098 8272 4072 8304
TIME...MOT...LOC 1927Z 217DEG 23KT 4084 8308

Kahn