Alert archive / West Virginia / Mesoscale Discussions in 2011
Mesoscale Discussion 486
The Storm Prediction Center issued this mesoscale discussion at Apr 20, 2011, 3:20 AM EDT for 6 states. It was in force for 85 min.
The area
The outline as issued.
The facts
- Issued
- Apr 20, 2011, 3:20 AM EDT (07:20 UTC)
- Expired
- Apr 20, 2011, 4:45 AM EDT
- In force
- 85 min
- Issued by
- the Storm Prediction Center
All 142 counties
Bell County, KY, Boyd County, KY, Breathitt County, KY, Clay County, KY, Clinton County, KY, Cumberland County, KY, Elliott County, KY, Floyd County, KY, Harlan County, KY, Jackson County, KY, Johnson County, KY, Knott County, KY, Knox County, KY, Laurel County, KY, Lawrence County, KY, Lee County, KY, Leslie County, KY, Letcher County, KY, Magoffin County, KY, Martin County, KY, McCreary County, KY, Morgan County, KY, Owsley County, KY, Perry County, KY, Pike County, KY, Pulaski County, KY, Wayne County, KY, Whitley County, KY, Wolfe County, KY, Athens County, OH, Belmont County, OH, Carroll County, OH, Columbiana County, OH, Gallia County, OH, Guernsey County, OH, Harrison County, OH, Jefferson County, OH, Lawrence County, OH, Mahoning County, OH, Meigs County, OH, Monroe County, OH, Morgan County, OH, Noble County, OH, Trumbull County, OH, Washington 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, Lawrence County, PA, Mercer County, PA, Venango County, PA, Warren County, PA, Washington County, PA, Westmoreland County, PA, Anderson County, TN, Bledsoe County, TN, Campbell County, TN, Claiborne County, TN, Clay County, TN, Cumberland County, TN, Fentress County, TN, Grainger County, TN, Hamblen County, TN, Hancock County, TN, Hawkins County, TN, Jackson County, TN, Jefferson County, TN, Knox County, TN, Loudon County, TN, Meigs County, TN, Morgan County, TN, Overton County, TN, Pickett County, TN, Putnam County, TN, Rhea County, TN, Roane County, TN, Scott County, TN, Sequatchie County, TN, Sullivan County, TN, Union County, TN, Van Buren County, TN, Warren County, TN, White County, TN, Buchanan County, VA, City of Bristol, VA, City of Norton, VA, Dickenson County, VA, Lee County, VA, Russell County, VA, Scott County, VA, Tazewell County, VA, Washington County, VA, Wise County, VA, Barbour County, WV, Boone County, WV, Braxton County, WV, Brooke County, WV, Cabell County, WV, Calhoun County, WV, Clay County, WV, Doddridge County, WV, Fayette County, WV, Gilmer County, WV, Hancock County, WV, Harrison County, WV, Jackson County, WV, Kanawha County, WV, Lewis County, WV, Lincoln County, WV, Logan County, WV, Marion County, WV, Marshall County, WV, Mason County, WV, McDowell County, WV, Mercer County, WV, Mingo County, WV, Monongalia County, WV, Nicholas County, WV, Ohio County, WV, Pleasants County, WV, Preston County, WV, Putnam County, WV, Raleigh County, WV, Ritchie County, WV, Roane County, WV, Summers County, WV, Taylor County, WV, Tyler County, WV, Upshur County, WV, Wayne County, WV, Webster County, WV, Wetzel County, WV, Wirt County, WV, Wood County, WV, Wyoming County, WV
The radar
The Jackson,KY radar (KJKL), 50 km from the middle of the area, began a volume at 07:20 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
Cncnati-Daytn, OH (KILN), launched 00:00Z, 7.3 hours before the alert went out and 170 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
- 1686 J/kg
- Mixed-layer CIN
- -39 J/kg
- Mixed-layer LCL
- 1003 m above ground
- 0-6 km bulk shear
- 51 kt
- 0-1 km storm-relative helicity
- 387 m²/s²
- 0-3 km storm-relative helicity
- 474 m²/s²
- Significant tornado parameter
- 4.3
- Supercell composite
- 18.7
The text
As transmitted, in the capitals the NWS used until 2016.
468
ACUS11 KWNS 200720
SWOMCD
SPC MCD 200720
PAZ000-NYZ000-WVZ000-OHZ000-VAZ000-TNZ000-KYZ000-200845-
MESOSCALE DISCUSSION 0486
NWS STORM PREDICTION CENTER NORMAN OK
0220 AM CDT WED APR 20 2011
AREAS AFFECTED...ERN OH...WRN PA...WV...ERN KY...MIDDLE AND ERN TN
CONCERNING...TORNADO WATCH 163...165...
VALID 200720Z - 200845Z
THE SEVERE WEATHER THREAT FOR TORNADO WATCH 163...165...CONTINUES.
SEVERE THREAT ALSO CONTINUES FOR SEVERE THUNDERSTORM WATCH 164.
EXTENSIVE PRE-FRONTAL SQUALL LINE IS PROBABLY PAST PEAK CONVECTIVE
INTENSITY...AND EASTERLY SYSTEM-RELATIVE LOW-LEVEL INFLOW EMANATING
FROM A DRIER ENVIRONMENT ALONG THE WESTERN SLOPES OF THE
APPALACHIANS SHOULD RESULT IN CONTINUED WEAKENING TRENDS...EVEN WITH
SOME MOISTENING OF THIS AIR MASS STILL POSSIBLE. HOWEVER...THE
CONGLOMERATE SURFACE COLD POOL GENERATED BY THE CONVECTIVE SYSTEM IS
LIKELY TO BE SLOWER TO WEAKEN...AND WILL PROBABLY CONTINUE TO BE
ACCOMPANIED BY AT LEAST THE RISK FOR POTENTIALLY DAMAGING WIND GUSTS
INTO THE CREST OF THE APPALACHIANS BETWEEN NOW AND 10-11Z. STRONGER
EMBEDDED COLD POOLS ARE STILL SURGING EAST AT UP TO 60 KTS...SO
SWATHS OF LOCALLY VERY STRONG WINDS ALONG THE GUST FRONTS WILL
REMAIN POSSIBLE AT LEAST ANOTHER COUPLE OF HOURS.
..KERR.. 04/20/2011
...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
ATTN...WFO...BUF...CTP...RNK...PBZ...RLX...CLE...MRX...JKL...
ILN...LMK...OHX...
LAT...LON 35498597 36018580 36618565 36738556 37378425 37988329
39678194 40628128 41928070 42067928 40617895 37878051
36398236 35268504 35498597SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Apr 19, 9:07 PM EDT | Mesoscale Discussion | SPC | Ballard, Carlisle, Crittenden, Fulton, Graves, Henderson and 5 more | 83 min |
| Apr 19, 9:47 PM EDT | Mesoscale Discussion | SPC | Adair, Anderson, Barren, Boone, Boyle, Bracken and 35 more | 88 min |
| Apr 19, 10:13 PM EDT | Tornado Watch | SPC | Adair, Allen, Anderson, Barren, Boone, Bourbon and 55 more | 6 hr |
| Apr 20, 12:56 AM EDT | Mesoscale Discussion | SPC | Adair, Allen, Anderson, Barren, Bath, Boone and 83 more | 94 min |
| Apr 20, 1:59 AM EDT | Tornado Watch | SPC | Bath, Bell, Boyd, Breathitt, Carter, Clay and 31 more | 5 hr |
| Apr 19, 9:37 PM EDT | Severe Thunderstorm Watch | SPC | Allen, Defiance, Fulton, Henry, Paulding, Putnam and 2 more | 3 hr |
| Apr 19, 11:47 PM EDT | Mesoscale Discussion | SPC | Ashland, Carroll, Crawford, Fulton, Hancock, Henry and 14 more | 58 min |
| Apr 20, 12:18 AM EDT | Severe Thunderstorm Watch | SPC | Ashland, Ashtabula, Crawford, Erie, Geauga, Hancock and 21 more | 4 hr |
| Apr 20, 2:22 AM EDT | Severe Thunderstorm Watch | SPC | Belmont, Carroll, Columbiana, Coshocton, Guernsey, Harrison and 5 more | 3 hr |
| Apr 20, 3:45 PM EDT | Mesoscale Discussion | SPC | Adams, Bedford, Berks, Blair, Bradford, Cambria and 30 more | 30 min |
| Apr 20, 4:03 PM EDT | Severe Thunderstorm Watch | SPC | Adams, Bedford, Berks, Blair, Bradford, Carbon and 29 more | 4 hr |
| Apr 19, 10:39 PM EDT | Mesoscale Discussion | SPC | Bedford, Benton, Cannon, Carroll, Cheatham, Chester and 23 more | 66 min |
| Apr 19, 11:14 PM EDT | Tornado Watch | SPC | Bedford, Benton, Carroll, Cheatham, Chester, Clay and 31 more | 7 hr |
| Apr 20, 2:42 AM EDT | Tornado Watch | SPC | Anderson, Bledsoe, Blount, Bradley, Campbell, Cannon and 42 more | 5 hr |
Nearby
Mesoscale Discussions in West Virginia, 2011Mesoscale Discussions in Kentucky, 2011Mesoscale Discussions in Tennessee, 2011Every mesoscale discussion in 2011
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.