Alert archive / Virginia / Mesoscale Discussions in 2021
Mesoscale Discussion 1350
The Storm Prediction Center issued this mesoscale discussion at Jul 26, 2021, 12:58 PM EDT for 23 counties in North Carolina; 38 counties in Virginia. It was in force for 2 hr.
The area
The outline as issued.
The facts
- Issued
- Jul 26, 2021, 12:58 PM EDT (16:58 UTC)
- Expired
- Jul 26, 2021, 3:00 PM EDT
- In force
- 2 hr
- Issued by
- the Storm Prediction Center
- Concerning
- Severe potential...watch likely
- Chance of a watch
- 80%
All 61 counties
Alamance County, NC, Cabarrus County, NC, Caswell County, NC, Chatham County, NC, Davidson County, NC, Davie County, NC, Durham County, NC, Forsyth County, NC, Franklin County, NC, Granville County, NC, Guilford County, NC, Iredell County, NC, Montgomery County, NC, Orange County, NC, Person County, NC, Randolph County, NC, Rockingham County, NC, Rowan County, NC, Stanly County, NC, Stokes County, NC, Vance County, NC, Warren County, NC, Yadkin County, NC, Amelia County, VA, Appomattox County, VA, Brunswick County, VA, Buckingham County, VA, Campbell County, VA, Caroline County, VA, Charles City County, VA, Charlotte County, VA, Chesterfield County, VA, City of Colonial Heights, VA, City of Danville, VA, City of Emporia, VA, City of Hopewell, VA, City of Lynchburg, VA, City of Martinsville, VA, City of Petersburg, VA, City of Richmond, VA, Cumberland County, VA, Dinwiddie County, VA, Fluvanna County, VA, Goochland County, VA, Greensville County, VA, Halifax County, VA, Hanover County, VA, Henrico County, VA, Henry County, VA, King William County, VA, Louisa County, VA, Lunenburg County, VA, Mecklenburg County, VA, New Kent County, VA, Nottoway County, VA, Patrick County, VA, Pittsylvania County, VA, Powhatan County, VA, Prince Edward County, VA, Prince George County, VA, Sussex County, VA
The radar
The Roanoke radar (KFCX), 110 km from the middle of the area, began a volume at 17:00 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 watches that followed
Watches SPC issued over any of the same counties within four hours of this discussion.
The nearest sounding before it
Greensboro/Hi Pt, NC (KGSO), launched 12:00Z, 5.0 hours before the alert went out and 76 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
- 401 J/kg
- Mixed-layer CIN
- -82 J/kg
- Mixed-layer LCL
- 925 m above ground
- 0-6 km bulk shear
- 18 kt
- 0-1 km storm-relative helicity
- 92 m²/s²
- 0-3 km storm-relative helicity
- 62 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
592
ACUS11 KWNS 261658
SWOMCD
SPC MCD 261658
VAZ000-NCZ000-261900-
Mesoscale Discussion 1350
NWS Storm Prediction Center Norman OK
1158 AM CDT Mon Jul 26 2021
Areas affected...Central/eastern Virginia...central North Carolina
Concerning...Severe potential...Watch likely
Valid 261658Z - 261900Z
Probability of Watch Issuance...80 percent
SUMMARY...Scattered storms are developing along the Blue Ridge and
will pose a threat for damaging winds as they move
east/southeastward this afternoon. The threat will be maximized with
any clusters that can develop. A severe thunderstorm watch is likely
for parts of Virginia/North Carolina.
DISCUSSION...Scattered thunderstorms are in the process of forming
along the Blue Ridge. With temperatures in the mid/upper 80s F and
dewpoints in the low/mid 70s, 1500-2000 J/kg MLCAPE has already
developed. Continued heating this afternoon will probably bring
temperatures near to just above 90 F in spots. Given the depth of
the moist layer on 12Z observed regional soundings, dewpoints should
generally hold steady as well. Despite weak deep-layer shear, storm
coverage and congealing cold pools seem likely to lead to a few
semi-organized clusters capable of damaging wind gusts. Slightly
cooler temperatures aloft in Virginia give slightly higher
confidence to more intense/organized activity than farther to the
south. A severe thunderstorm watch will likely be needed this
afternoon as activity continues to slowly intensify over the next
few hours.
..Wendt/Wendt.. 07/26/2021
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...AKQ...LWX...RAH...RNK...GSP...
LAT...LON 35548126 36168100 37517918 38037794 38107725 37387693
36367749 35357965 34998028 35548126SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jul 26, 1:39 PM EDT | Severe Thunderstorm Watch | SPC | Alamance, Caswell, Davidson, Forsyth, Guilford, Orange and 4 more | 6 hr |
| Jul 26, 3:29 PM EDT | Mesoscale Discussion | SPC | Alamance, Caswell, Davidson, Durham, Forsyth, Granville and 10 more | 2 hr |
| Jul 26, 5:43 PM EDT | Mesoscale Discussion | SPC | Camden, Chowan, Currituck, Gates, Hertford, Pasquotank and 3 more | 92 min |
Nearby
Mesoscale Discussions in Virginia, 2021Mesoscale Discussions in North Carolina, 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.