Alert archive / West Virginia / Mesoscale Discussions in 2021
Mesoscale Discussion 1239
The Storm Prediction Center issued this mesoscale discussion at Jul 10, 2021, 2:32 PM EDT for 16 counties in West Virginia. It was in force for 118 min.
The area
The outline as issued.
The facts
- Issued
- Jul 10, 2021, 2:32 PM EDT (18:32 UTC)
- Expired
- Jul 10, 2021, 4:30 PM EDT
- In force
- 118 min
- Issued by
- the Storm Prediction Center
- Concerning
- Severe potential...watch unlikely
- Chance of a watch
- 20%
Counties Boone County, WV, Braxton County, WV, Clay County, WV, Fayette County, WV, Greenbrier County, WV, Kanawha County, WV, Logan County, WV, McDowell County, WV, Mercer County, WV, Nicholas County, WV, Pocahontas County, WV, Raleigh County, WV, Randolph County, WV, Summers County, WV, Webster County, WV, Wyoming County, WV
The radar
The Charleston,WV radar (KRLX), 77 km from the middle of the area, began a volume at 18:34 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, 6.5 hours before the alert went out and 156 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
- 1182 m above ground
- 0-6 km bulk shear
- 21 kt
- 0-1 km storm-relative helicity
- -38 m²/s²
- 0-3 km storm-relative helicity
- 6 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- -0.0
The text
As transmitted.
345
ACUS11 KWNS 101833
SWOMCD
SPC MCD 101832
WVZ000-VAZ000-KYZ000-102030-
Mesoscale Discussion 1239
NWS Storm Prediction Center Norman OK
0132 PM CDT Sat Jul 10 2021
Areas affected...portions of central into eastern West Virginia
Concerning...Severe potential...Watch unlikely
Valid 101832Z - 102030Z
Probability of Watch Issuance...20 percent
SUMMARY...At least a few damaging gusts remain possible over the
next few hours. However, the spatial coverage of severe winds is
expected to be relatively low overall and a Severe Thunderstorm
Watch issuance is not currently anticipated.
DISCUSSION...MRMS mosaic and KRLX radar data depict a small but
highly organized MCS propagating across central WV, with
semi-discrete storms exhibiting occasional transient supercell
structures to the south of the bowing complex (some with a history
of tree damage).
30-35 kts of effective bulk shear is evident across the Ohio
Valley/Mid-Atlantic regions based on 18Z mesoanalysis, with the
shear vectors orthogonal to the MCS. The bowing-structure MCS and
nearby transient supercells are expected to remain organized through
the mid afternoon hours. Nonetheless, buoyancy is marginal, with
generally less than 500 J/kg MLCAPE noted (fueled primarily by 7-8
C/km low-level lapse rates). The KRLX showed mainly 30-40 kts of
leading-line flow about 200-500 ft AGL, and significant
intensification is not expected. As such, gusty winds may accompany
the stronger storms/bowing segments, and while a few severe gusts
cannot be ruled out, the lack of more widespread damaging wind
potential suggests a Severe Thunderstorm Watch is not needed.
..Squitieri/Bunting.. 07/10/2021
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...LWX...RNK...RLX...JKL...
LAT...LON 37428203 38218197 38628178 38818112 38808029 38787975
38727964 38527962 38087986 37628046 37368109 37198153
37198155 37428203Nearby
Mesoscale 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.