Alert archive / Ohio / Mesoscale Discussions in 2017
Mesoscale Discussion 615
The Storm Prediction Center issued this mesoscale discussion at Apr 30, 2017, 2:58 PM EDT for 5 states. It was in force for 2 hr.
The area
The outline as issued.
The facts
- Issued
- Apr 30, 2017, 2:58 PM EDT (18:58 UTC)
- Expired
- Apr 30, 2017, 5:00 PM EDT
- In force
- 2 hr
- Issued by
- the Storm Prediction Center
- Chance of a watch
- 5%
All 75 counties
Greenup County, KY, Garrett County, MD, Athens County, OH, Belmont County, OH, Carroll County, OH, Columbiana County, OH, Coshocton County, OH, Fairfield County, OH, Gallia County, OH, Guernsey County, OH, Harrison County, OH, Hocking County, OH, Holmes County, OH, Jackson County, OH, Jefferson County, OH, Lawrence County, OH, Mahoning County, OH, Meigs County, OH, Monroe County, OH, Morgan County, OH, Muskingum County, OH, Noble County, OH, Perry County, OH, Portage County, OH, Scioto 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, Fayette County, PA, Forest County, PA, Greene County, PA, Indiana County, PA, Jefferson County, PA, Lawrence County, PA, Mercer County, PA, Venango County, PA, Washington County, PA, Westmoreland County, PA, Barbour County, WV, Braxton County, WV, Brooke County, WV, Calhoun County, WV, Doddridge County, WV, Gilmer County, WV, Hancock County, WV, Harrison County, WV, Jackson County, WV, Lewis County, WV, Marion County, WV, Marshall County, WV, Mason County, WV, Monongalia County, WV, Ohio County, WV, Pleasants County, WV, Preston County, WV, Randolph County, WV, Ritchie County, WV, Roane County, WV, Taylor County, WV, Tucker County, WV, Tyler County, WV, Upshur County, WV, Wetzel County, WV, Wirt County, WV, Wood County, WV
The radar
The Pittsburgh radar (KPBZ), 68 km from the middle of the area, began a volume at 19:00 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 (KAGC), launched 12:00Z, 7.0 hours before the alert went out and 78 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
- 9 J/kg
- Mixed-layer CIN
- -263 J/kg
- Mixed-layer LCL
- 1041 m above ground
- 0-6 km bulk shear
- 45 kt
- 0-1 km storm-relative helicity
- 209 m²/s²
- 0-3 km storm-relative helicity
- 232 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.1
The text
As transmitted.
560
ACUS11 KWNS 301858
SWOMCD
SPC MCD 301858
PAZ000-MDZ000-WVZ000-OHZ000-KYZ000-302100-
Mesoscale Discussion 0615
NWS Storm Prediction Center Norman OK
0158 PM CDT Sun Apr 30 2017
Areas affected...Central/Eastern OH...Western PA...Central/Northern
WV
Concerning...Severe potential...Watch unlikely
Valid 301858Z - 302100Z
Probability of Watch Issuance...5 percent
SUMMARY...Isolated damaging wind gusts are possible but the limited
severe threat is expected to preclude the need for a watch.
DISCUSSION...Transient updrafts have been noted for several hours
within the warm-air advection regime across the region. Robust
development has been largely absent thus far but recent radar and
satellite imagery better vertical development across OH where the
leading edge of the large-scale height falls are likely impinging on
the region. Despite warm and moist surface conditions (i.e.
temperatures in the 80s and dewpoints in the low 60s), warm
temperatures aloft and poor mid-level lapse rates will limit
instability. Shear is strong enough for a few more organized
updrafts capable of isolated damaging wind gusts. A wet downburst or
two may also occur as a result of storm interactions and the
resultant water-loading. However, the general expectation is for the
majority of storms to remain sub-severe and the overall severe
threat to remain low.
..Mosier/Grams.. 04/30/2017
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...CTP...LWX...PBZ...RLX...CLE...ILN...
LAT...LON 40698214 41468128 41878007 41347876 38687942 38468333
40698214SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Apr 30, 1:54 AM EDT | Mesoscale Discussion | SPC | Ballard, Carlisle, Fulton, Graves, Hickman | 96 min |
| Apr 30, 2:10 AM EDT | Severe Thunderstorm Watch | SPC | Calloway, Carlisle, Fulton, Graves, Hickman | 6 hr |
| Apr 30, 3:58 AM EDT | Mesoscale Discussion | SPC | Ballard, Calloway, Carlisle, Fulton, Graves, Hickman and 3 more | 92 min |
| Apr 30, 2:21 PM EDT | Mesoscale Discussion | SPC | Simpson | 54 min |
| Apr 30, 4:58 PM EDT | Mesoscale Discussion | SPC | Adair, Barren, Boyle, Casey, Clinton, Cumberland and 14 more | 92 min |
| Apr 30, 3:25 PM EDT | Mesoscale Discussion | SPC | Allegany, Anne Arundel, Baltimore, Calvert, Carroll, Charles and 12 more | 95 min |
Nearby
Mesoscale Discussions in Ohio, 2017Mesoscale Discussions in West Virginia, 2017Mesoscale Discussions in Pennsylvania, 2017Every mesoscale discussion in 2017
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.