Alert archive / Ohio / Mesoscale Discussions in 2021
Mesoscale Discussion 1045
The Storm Prediction Center issued this mesoscale discussion at Jun 21, 2021, 11:59 AM EDT for 4 states. It was in force for 91 min.
The area
The outline as issued.
The facts
- Issued
- Jun 21, 2021, 11:59 AM EDT (15:59 UTC)
- Expired
- Jun 21, 2021, 1:30 PM EDT
- In force
- 91 min
- Issued by
- the Storm Prediction Center
- Concerning
- Severe potential...watch likely
- Chance of a watch
- 80%
All 63 counties
Cattaraugus County, NY, Chautauqua County, NY, Ashland County, OH, Ashtabula County, OH, Athens County, OH, Belmont County, OH, Carroll County, OH, Columbiana County, OH, Coshocton County, OH, Cuyahoga County, OH, Delaware County, OH, Fairfield County, OH, Franklin County, OH, Geauga County, OH, Guernsey County, OH, Harrison County, OH, Hocking County, OH, Holmes County, OH, Jefferson County, OH, Knox County, OH, Lake County, OH, Licking County, OH, Mahoning County, OH, Medina County, OH, Monroe County, OH, Morgan County, OH, Morrow County, OH, Muskingum County, OH, Noble County, OH, Perry County, OH, Portage County, OH, Richland County, OH, Stark County, OH, Summit County, OH, Trumbull County, OH, Tuscarawas County, OH, Vinton County, OH, Washington County, OH, Wayne County, OH, Allegheny County, PA, Armstrong County, PA, Beaver County, PA, Butler County, PA, Clarion County, PA, Crawford County, PA, Elk County, PA, Erie County, PA, Forest County, PA, Greene County, PA, Jefferson County, PA, Lawrence County, PA, McKean County, PA, Mercer County, PA, Venango County, PA, Warren County, PA, Washington County, PA, Westmoreland County, PA, Brooke County, WV, Hancock County, WV, Marshall County, WV, Ohio County, WV, Pleasants County, WV, Wetzel County, WV
The radar
The Pittsburgh radar (KPBZ), 62 km from the middle of the area, began a volume at 15:59 UTC, the scan nearest the moment this went out.
Open the radar archive at this moment
The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.
The watches that followed
Watches SPC issued over any of the same counties within four hours of this discussion.
The nearest sounding before it
Pittsburgh, PA (KPIT), launched 12:00Z, 4.0 hours before the alert went out and 79 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.
- Mixed-layer CAPE
- 931 J/kg
- Mixed-layer CIN
- -41 J/kg
- Mixed-layer LCL
- 988 m above ground
- 0-6 km bulk shear
- 37 kt
- 0-1 km storm-relative helicity
- 260 m²/s²
- 0-3 km storm-relative helicity
- 277 m²/s²
- Significant tornado parameter
- 1.0
- Supercell composite
- 5.1
The text
As transmitted.
196
ACUS11 KWNS 211600
SWOMCD
SPC MCD 211559
NYZ000-PAZ000-WVZ000-OHZ000-211730-
Mesoscale Discussion 1045
NWS Storm Prediction Center Norman OK
1059 AM CDT Mon Jun 21 2021
Areas affected...Eastern Ohio...Western Pennsylvania...southwest New
York...and portions of West Virginia
Concerning...Severe potential...Watch likely
Valid 211559Z - 211730Z
Probability of Watch Issuance...80 percent
SUMMARY...A severe storm threat is expected to increase over the
next 1 to 2 hours. A watch is likely.
DISCUSSION...Showers have developed along the cold front in
east-central Ohio. Expect these showers to develop into
thunderstorms and strengthen as the boundary layer warms and
destabilizes ahead of this activity. Dewpoints are in the upper 60s
to low 70s across much of the Upper Ohio Valley and into the
Northeast. 12Z RAOBs show deep moisture near the surface which
suggests dewpoints likely won't decrease much, even as the boundary
layer mixing deepens. Therefore, an unstable airmass is forecast
with MLCAPE in excess of 2000 J/kg. The 1530Z VWP from KCLE observed
the vertical wind profile well which, as expected, is similar to the
PIT 12Z RAOB. Winds as high as 35 to 40 knots extend as low as 1 km
with mid-level flow around 50 knots. This shear profile will be
supportive of organized convection including supercells and bowing
line segments. In addition, the strong flow within 1km of the
surface should aid downward transport of strong winds. Therefore,
damaging winds are expected to be the primary hazard. Large hail may
also occur, especially with any supercells which may develop. In
addition, strong speed shear in the low-levels could support the
threat of a tornado or two, but veered surface flow will likely
preclude a greater tornado threat.
..Bentley/Hart.. 06/21/2021
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...BUF...CTP...PBZ...RLX...CLE...ILN...
LAT...LON 39938303 40318319 40728285 41398214 41948091 42327996
42387957 42677901 42717854 42137827 41957848 41397858
40647913 39737980 39638050 39268135 39228253 39648283
39938303SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jun 21, 12:31 PM EDT | Mesoscale Discussion | SPC | Clinton, Essex, Franklin, Fulton, Hamilton, Herkimer and 12 more | 89 min |
| Jun 21, 12:31 PM EDT | Severe Thunderstorm Watch | SPC | Allegany, Cattaraugus, Cayuga, Chautauqua, Erie, Genesee and 14 more | 7 hr |
| Jun 21, 1:11 PM EDT | Severe Thunderstorm Watch | SPC | Broome, Chemung, Chenango, Clinton, Cortland, Essex and 14 more | 10 hr |
| Jun 21, 3:35 PM EDT | Mesoscale Discussion | SPC | Clinton, Essex, Franklin, Fulton, Hamilton, Herkimer and 7 more | 85 min |
| Jun 21, 3:45 PM EDT | Severe Thunderstorm Watch | SPC | Albany, Columbia, Delaware, Dutchess, Greene, Otsego and 5 more | 7 hr |
| Jun 21, 3:47 PM EDT | Mesoscale Discussion | SPC | Allegany, Livingston, Ontario, Steuben, Wayne, Yates | 58 min |
| Jun 21, 4:33 PM EDT | Severe Thunderstorm Watch | SPC | Orange | 6 hr |
| Jun 21, 6:50 PM EDT | Mesoscale Discussion | SPC | Albany, Broome, Chenango, Columbia, Cortland, Delaware and 23 more | 55 min |
| Jun 20, 8:14 PM EDT | Mesoscale Discussion | SPC | Allen, Auglaize, Defiance, Erie, Fulton, Hancock and 15 more | 61 min |
| Jun 20, 11:51 PM EDT | Mesoscale Discussion | SPC | Defiance, Fulton, Hancock, Henry, Lucas, Ottawa and 7 more | 54 min |
| Jun 21, 1:00 AM EDT | Severe Thunderstorm Watch | SPC | Ashtabula, Cuyahoga, Defiance, Erie, Fulton, Geauga and 11 more | 7 hr |
| Jun 21, 2:14 AM EDT | Mesoscale Discussion | SPC | Defiance, Fulton, Henry, Lucas, Ottawa, Paulding and 3 more | 2 hr |
| Jun 21, 1:51 PM EDT | Mesoscale Discussion | SPC | Adams, Bedford, Berks, Blair, Bradford, Bucks and 37 more | 114 min |
| Jun 21, 2:20 PM EDT | Severe Thunderstorm Watch | SPC | Adams, Bedford, Blair, Centre, Clinton, Columbia and 19 more | 6 hr |
| Jun 21, 6:15 PM EDT | Mesoscale Discussion | SPC | Bucks, Chester, Delaware, Lancaster, Montgomery, Philadelphia | 60 min |
Nearby
Mesoscale Discussions in Ohio, 2021Mesoscale Discussions in Pennsylvania, 2021Mesoscale Discussions in West Virginia, 2021Every mesoscale discussion in 2021
Sources
The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.