Alert archive / West Virginia / Mesoscale Discussions in 2021
Mesoscale Discussion 959
The Storm Prediction Center issued this mesoscale discussion at Jun 13, 2021, 7:05 PM EDT for Martin County, Kentucky; 9 counties in Virginia; 12 counties in West Virginia. It was in force for 85 min.
The area
The outline as issued.
The facts
- Issued
- Jun 13, 2021, 7:05 PM EDT (23:05 UTC)
- Expired
- Jun 13, 2021, 8:30 PM EDT
- In force
- 85 min
- Issued by
- the Storm Prediction Center
- Concerning
- Severe thunderstorm watch 267
All 22 counties
Martin County, KY, Alleghany County, VA, Bath County, VA, Botetourt County, VA, City of Covington, VA, City of Roanoke, VA, City of Salem, VA, Craig County, VA, Giles County, VA, Roanoke County, VA, Boone County, WV, Fayette County, WV, Greenbrier County, WV, Logan County, WV, McDowell County, WV, Mercer County, WV, Mingo County, WV, Monroe County, WV, Nicholas County, WV, Raleigh County, WV, Summers County, WV, Wyoming County, WV
The radar
The Charleston,WV radar (KRLX), 87 km from the middle of the area, began a volume at 23:07 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
Roanoke, VA (KRNK), launched 12:00Z, 11.1 hours before the alert went out and 148 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
- 60 J/kg
- Mixed-layer CIN
- -22 J/kg
- Mixed-layer LCL
- 614 m above ground
- 0-6 km bulk shear
- 11 kt
- 0-1 km storm-relative helicity
- 22 m²/s²
- 0-3 km storm-relative helicity
- 58 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
715
ACUS11 KWNS 132306
SWOMCD
SPC MCD 132305
VAZ000-WVZ000-KYZ000-140030-
Mesoscale Discussion 0959
NWS Storm Prediction Center Norman OK
0605 PM CDT Sun Jun 13 2021
Areas affected...Central Appalachians
Concerning...Severe Thunderstorm Watch 267...
Valid 132305Z - 140030Z
The severe weather threat for Severe Thunderstorm Watch 267
continues.
SUMMARY...Thunderstorms will propagate from north to south across
ww267. Locally damaging winds remain possible.
DISCUSSION...Northwesterly high-level diffluent flow remains
favorable for southward-propagating convection this evening. Latest
diagnostic data suggests a weak mid-level short-wave trough may be
embedded within this flow and is likely contributing to an extensive
corridor of convection that stretches from central PA-KY. Over the
last few hours, a slow-moving MCS has evolved across central WV,
extending into western VA. This activity is moving south at roughly
20kt into a region of yet-to-be overturned air where low-level lapse
rates remain steep and instability sufficient for robust updrafts.
The primary concern is locally damaging winds as this convection
spreads toward the southern portions of ww267. At the current
speed/movement, leading edge of the MCS should exit the watch around
expiration.
..Darrow.. 06/13/2021
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...RNK...RLX...JKL...
LAT...LON 37758279 38558077 38247980 37447925 37188024 37288161
37758279SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jun 13, 12:50 PM EDT | Severe Thunderstorm Watch | SPC | Boyd, Greenup | 7 hr |
| Jun 13, 2:04 PM EDT | Mesoscale Discussion | SPC | Anderson, Bath, Boone, Bourbon, Boyle, Bracken and 48 more | 56 min |
| Jun 13, 3:26 PM EDT | Mesoscale Discussion | SPC | Boyd, Greenup | 94 min |
| Jun 13, 4:31 PM EDT | Mesoscale Discussion | SPC | Bath, Boyd, Carter, Elliott, Fleming, Floyd and 11 more | 89 min |
| Jun 13, 4:56 PM EDT | Severe Thunderstorm Watch | SPC | Carter, Elliott, Floyd, Johnson, Lawrence, Martin and 1 more | 5 hr |
| Jun 13, 12:13 PM EDT | Mesoscale Discussion | SPC | Frederick, Rockingham, Shenandoah, City of Winchester | 2 hr |
| Jun 13, 12:32 PM EDT | Mesoscale Discussion | SPC | Arlington, Clarke, Culpeper, Fairfax, Fauquier, Frederick and 13 more | 118 min |
Nearby
Mesoscale Discussions in West Virginia, 2021Mesoscale Discussions in Virginia, 2021Mesoscale Discussions in Kentucky, 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.