Alert archive / Virginia / Mesoscale Discussions in 2021
Mesoscale Discussion 1902
The Storm Prediction Center issued this mesoscale discussion at Oct 25, 2021, 8:13 PM EDT for Saint Mary's County, Maryland; 10 counties in North Carolina; 35 counties in Virginia. It was in force for 92 min.
The area
The outline as issued.
The facts
- Issued
- Oct 25, 2021, 8:13 PM EDT (00:13 UTC)
- Expired
- Oct 25, 2021, 9:45 PM EDT
- In force
- 92 min
- Issued by
- the Storm Prediction Center
- Concerning
- Severe thunderstorm watch 535
All 46 counties
Saint Mary's County, MD, Alamance County, NC, Caswell County, NC, Durham County, NC, Forsyth County, NC, Granville County, NC, Guilford County, NC, Orange County, NC, Person County, NC, Rockingham County, NC, Vance County, NC, Amelia County, VA, Appomattox County, VA, Brunswick County, VA, Buckingham County, VA, Caroline County, VA, Charlotte County, VA, Chesterfield County, VA, City of Colonial Heights, VA, City of Danville, VA, City of Fredericksburg, VA, City of Hopewell, VA, City of Petersburg, VA, City of Richmond, VA, Cumberland County, VA, Dinwiddie County, VA, Essex County, VA, Fluvanna County, VA, Goochland County, VA, Halifax County, VA, Hanover County, VA, Henrico County, VA, King and Queen County, VA, King George County, VA, King William County, VA, Louisa County, VA, Lunenburg County, VA, Mecklenburg County, VA, New Kent County, VA, Nottoway County, VA, Pittsylvania County, VA, Powhatan County, VA, Prince Edward County, VA, Richmond County, VA, Spotsylvania County, VA, Westmoreland County, VA
The radar
The Raleigh/Durham radar (KRAX), 144 km from the middle of the area, began a volume at 00:17 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 00:00Z, 0.2 hours before the alert went out and 81 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
- 857 m above ground
- 0-6 km bulk shear
- 57 kt
- 0-1 km storm-relative helicity
- -105 m²/s²
- 0-3 km storm-relative helicity
- -66 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
619 ACUS11 KWNS 260013 SWOMCD SPC MCD 260013 MDZ000-VAZ000-NCZ000-260145- Mesoscale Discussion 1902 NWS Storm Prediction Center Norman OK 0713 PM CDT Mon Oct 25 2021 Areas affected...Middle Atlantic Concerning...Severe Thunderstorm Watch 535... Valid 260013Z - 260145Z The severe weather threat for Severe Thunderstorm Watch 535 continues. SUMMARY...Squall line will propagate across ww535 this evening. Damaging winds remain the primary threat. DISCUSSION...Exit region of mid-level speed max appears to be partly responsible for maturation of squall line that extends from northern VA into central NC. Although the linear MCS is not moving that fast, individual bow-type structures (Buckingham County VA) are surging east-northeast around 35kt. This activity is currently propagating across the maximum instability gradient so updraft intensity will likely be most efficient over the next few hours. Locally damaging winds remain the primary threat. ..Darrow.. 10/26/2021 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...AKQ...LWX...RAH...RNK...GSP... LAT...LON 36008050 38397768 38397584 35997868 36008050
Nearby
Mesoscale Discussions in Virginia, 2021Mesoscale Discussions in North Carolina, 2021Mesoscale Discussions in Maryland, 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.