Alert archive / Ohio / Mesoscale Discussions in 2021
Mesoscale Discussion 1881
The Storm Prediction Center issued this mesoscale discussion at Oct 21, 2021, 5:25 PM EDT for 11 counties in Ohio; Lawrence County, Mercer County, Pennsylvania. It was in force for 2 hr.
The area
The outline as issued.
The facts
- Issued
- Oct 21, 2021, 5:25 PM EDT (21:25 UTC)
- Expired
- Oct 21, 2021, 7:30 PM EDT
- In force
- 2 hr
- Issued by
- the Storm Prediction Center
- Concerning
- Severe potential...watch unlikely
- Chance of a watch
- 20%
Counties Carroll County, OH, Columbiana County, OH, Coshocton County, OH, Geauga County, OH, Harrison County, OH, Jefferson County, OH, Mahoning County, OH, Portage County, OH, Stark County, OH, Trumbull County, OH, Tuscarawas County, OH, Lawrence County, PA, Mercer County, PA
The radar
The Pittsburgh radar (KPBZ), 84 km from the middle of the area, began a volume at 21:25 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 nearest sounding before it
Pittsburgh, PA (KPIT), launched 12:00Z, 9.4 hours before the alert went out and 100 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
- 0 J/kg
- Mixed-layer CIN
- No buoyant parcel
- Mixed-layer LCL
- 1175 m above ground
- 0-6 km bulk shear
- 48 kt
- 0-1 km storm-relative helicity
- 105 m²/s²
- 0-3 km storm-relative helicity
- 188 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
758
ACUS11 KWNS 212126
SWOMCD
SPC MCD 212125
PAZ000-WVZ000-OHZ000-212330-
Mesoscale Discussion 1881
NWS Storm Prediction Center Norman OK
0425 PM CDT Thu Oct 21 2021
Areas affected...northeast OH...far western PA
Concerning...Severe potential...Watch unlikely
Valid 212125Z - 212330Z
Probability of Watch Issuance...20 percent
SUMMARY...The tornado risk will likely continue for another hour or
so (thru 600-630 pm EDT) and decrease towards sunset and likely be
very limited after sunset.
DISCUSSION...Radar imagery from Cleveland's 88D shows a broken band
of supercells immediately ahead of a strong mid-level vorticity
maximum moving east across the southern Great Lakes. Surface
temperatures have warmed into the low-mid 60s with dewpoints near 60
F. RAP forecast soundings indicate 100-250 J/kg MLCAPE with a
relatively straight hodograph yielding 150-225 m2/s2 0-1 km SRH.
The current expectation is for a continuation of the tornado risk
for the next hour or so given the sufficient buoyancy in place
across northeast OH. However, as the boundary layer begins to cool
this evening towards sunset and temperatures fall into the 60-62 deg
range, storm-scale rotation will gradually become more intermittent
and less intense. The tornado risk will correspondingly lessen as
supercell rotation weakens. The tornado risk will further diminish
after sunset as cooling further increases convective inhibition and
supercell rotation becomes more marginalized.
..Smith/Dial.. 10/21/2021
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...PBZ...CLE...
LAT...LON 40878149 41618112 41758020 41168008 40248090 40088214
40878149SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Oct 21, 2:39 PM EDT | Mesoscale Discussion | SPC | Adams, Ashland, Ashtabula, Athens, Belmont, Carroll and 36 more | 3 hr |
| Oct 21, 7:56 PM EDT | Mesoscale Discussion | SPC | Allegheny, Armstrong, Butler, Cambria, Clarion, Clearfield and 6 more | 2 hr |
Nearby
Mesoscale Discussions in Ohio, 2021Mesoscale Discussions in Pennsylvania, 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.