Alert archive / Virginia / Severe Thunderstorm Watches in 2021
Severe Thunderstorm Watch 78
The Storm Prediction Center issued this severe thunderstorm watch at Apr 9, 2021, 3:38 PM EDT for 20 counties in North Carolina; 28 counties in Virginia. It was in force for 7 hr.
The area
The outline as issued.
The facts
- Issued
- Apr 9, 2021, 3:38 PM EDT (19:38 UTC)
- Expired
- Apr 9, 2021, 10:50 PM EDT
- In force
- 7 hr
- Issued by
- the Storm Prediction Center
- Largest hail expected
- 1.5 in
- Strongest gust expected
- 60 kt
All 48 counties
Bertie County, NC, Camden County, NC, Caswell County, NC, Chowan County, NC, Edgecombe County, NC, Franklin County, NC, Gates County, NC, Granville County, NC, Halifax County, NC, Hertford County, NC, Nash County, NC, Northampton County, NC, Pasquotank County, NC, Perquimans County, NC, Person County, NC, Rockingham County, NC, Stokes County, NC, Surry County, NC, Vance County, NC, Warren County, NC, Brunswick County, VA, Carroll County, VA, Charlotte County, VA, City of Chesapeake, VA, City of Colonial Heights, VA, City of Danville, VA, City of Emporia, VA, City of Franklin, VA, City of Galax, VA, City of Hopewell, VA, City of Martinsville, VA, City of Petersburg, VA, City of Suffolk, VA, Dinwiddie County, VA, Floyd County, VA, Franklin County, VA, Greensville County, VA, Halifax County, VA, Henry County, VA, Isle of Wight County, VA, Lunenburg County, VA, Mecklenburg County, VA, Patrick County, VA, Pittsylvania County, VA, Prince George County, VA, Southampton County, VA, Surry County, VA, Sussex County, VA
The radar
The Raleigh/Durham radar (KRAX), 107 km from the middle of the area, began a volume at 19:40 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.
What SPC expected
The probabilities SPC published with the watch, for the watch area over its life.
- Two or more tornadoes
- 20%
- One or more EF2 to EF5 tornadoes
- 5%
- Ten or more severe wind reports
- 40%
- One or more gusts of 65 knots or more
- 20%
- Ten or more severe hail reports
- 40%
- One or more hailstones of 2 inches or more
- 20%
- Six or more combined severe hail and wind reports
- 70%
Warnings issued inside it
45 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Apr 9, 3:50 PM EDT | Severe Thunderstorm Warning | AKQ | City of Chesapeake | 40 min |
| Apr 9, 3:56 PM EDT | Severe Thunderstorm Warning | RNK | Franklin | 49 min |
| Apr 9, 4:07 PM EDT | Severe Thunderstorm Warning | RNK | Halifax | 23 min |
| Apr 9, 4:10 PM EDT | Severe Thunderstorm Warning | RAH | Granville, Person | 50 min |
| Apr 9, 4:11 PM EDT | Severe Thunderstorm Warning | RNK | Surry | 49 min |
| Apr 9, 4:14 PM EDT | Severe Thunderstorm Warning | AKQ | Mecklenburg | 46 min |
| Apr 9, 4:19 PM EDT | Severe Thunderstorm Warning | RNK | Franklin, Henry, Pittsylvania | 41 min |
| Apr 9, 4:20 PM EDT | Tornado Warning | RNK | Surry | 25 min |
| Apr 9, 4:28 PM EDT | Severe Thunderstorm Warning | AKQ | City of Suffolk | 28 min |
| Apr 9, 4:31 PM EDT | Severe Thunderstorm Warning | RNK | Halifax | 44 min |
| Apr 9, 4:34 PM EDT | Severe Thunderstorm Warning | AKQ | City of Chesapeake | 41 min |
| Apr 9, 4:35 PM EDT | Severe Thunderstorm Warning | RNK | Stokes | 55 min |
| Apr 9, 4:35 PM EDT | Severe Thunderstorm Warning | RNK | Floyd, Franklin, Patrick | 40 min |
| Apr 9, 4:40 PM EDT | Severe Thunderstorm Warning | RNK | Henry, Pittsylvania | 50 min |
| Apr 9, 4:44 PM EDT | Severe Thunderstorm Warning | RAH | Granville | 46 min |
| Apr 9, 4:45 PM EDT | Severe Thunderstorm Warning | AKQ | Isle of Wight, Surry, City of Hampton, City of Newport News | 45 min |
| Apr 9, 4:57 PM EDT | Severe Thunderstorm Warning | AKQ | Mecklenburg | 48 min |
| Apr 9, 5:06 PM EDT | Severe Thunderstorm Warning | AKQ | Bertie, Chowan, Perquimans | 39 min |
| Apr 9, 5:07 PM EDT | Severe Thunderstorm Warning | AKQ | Isle of Wight, City of Hampton, City of Newport News, City of Portsmouth, City of Suffolk | 53 min |
| Apr 9, 5:10 PM EDT | Severe Thunderstorm Warning | RNK | Pittsylvania | 36 min |
| Apr 9, 5:12 PM EDT | Severe Thunderstorm Warning | RAH | Granville, Vance, Warren | 63 min |
| Apr 9, 5:13 PM EDT | Severe Thunderstorm Warning | AKQ | City of Chesapeake, City of Virginia Beach | 47 min |
| Apr 9, 5:13 PM EDT | Severe Thunderstorm Warning | AKQ | Brunswick, Mecklenburg | 47 min |
| Apr 9, 5:13 PM EDT | Tornado Warning | RNK | Pittsylvania | 33 min |
| Apr 9, 5:27 PM EDT | Tornado Warning | RNK | Halifax, Pittsylvania | 48 min |
| Apr 9, 5:39 PM EDT | Severe Thunderstorm Warning | AKQ | City of Chesapeake, City of Portsmouth, City of Suffolk | 51 min |
| Apr 9, 5:42 PM EDT | Severe Thunderstorm Warning | AKQ | Bertie, Chowan, Perquimans | 48 min |
| Apr 9, 5:42 PM EDT | Tornado Warning | RAH | Person | 35 min |
| Apr 9, 5:55 PM EDT | Tornado Warning | RNK | Halifax | 50 min |
| Apr 9, 5:57 PM EDT | Severe Thunderstorm Warning | AKQ | Northampton | 48 min |
| Apr 9, 5:58 PM EDT | Severe Thunderstorm Warning | AKQ | City of Chesapeake, City of Virginia Beach | 47 min |
| Apr 9, 5:59 PM EDT | Severe Thunderstorm Warning | RAH | Warren | 46 min |
| Apr 9, 6:24 PM EDT | Severe Thunderstorm Warning | AKQ | Chowan, Perquimans | 51 min |
| Apr 9, 6:29 PM EDT | Severe Thunderstorm Warning | AKQ | Northampton | 46 min |
| Apr 9, 6:30 PM EDT | Severe Thunderstorm Warning | AKQ | Camden, Currituck | 45 min |
| Apr 9, 6:35 PM EDT | Severe Thunderstorm Warning | RAH | Halifax | 40 min |
| Apr 9, 6:39 PM EDT | Severe Thunderstorm Warning | AKQ | Mecklenburg | 51 min |
| Apr 9, 6:58 PM EDT | Severe Thunderstorm Warning | AKQ | Chowan | 24 min |
| Apr 9, 7:03 PM EDT | Severe Thunderstorm Warning | AKQ | Northampton | 42 min |
| Apr 9, 7:09 PM EDT | Severe Thunderstorm Warning | AKQ | Camden, Currituck | 51 min |
| Apr 9, 7:17 PM EDT | Severe Thunderstorm Warning | AKQ | Lunenburg, Mecklenburg | 43 min |
| Apr 9, 7:23 PM EDT | Severe Thunderstorm Warning | AKQ | Charles City, Prince George | 52 min |
| Apr 9, 7:34 PM EDT | Flash Flood Warning | AKQ | City of Chesapeake, City of Virginia Beach | 4 hr |
| Apr 9, 7:39 PM EDT | Severe Thunderstorm Warning | AKQ | Bertie, Hertford, Northampton | 51 min |
| Apr 9, 8:55 PM EDT | Flash Flood Warning | AKQ | City of Chesapeake | 3 hr |
Discussions around it
SPC mesoscale discussions over the same counties from four hours before the watch to its end.
The nearest sounding before it
Roanoke, VA (KRNK), launched 12:00Z, 7.6 hours before the alert went out and 92 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
- 132 J/kg
- Mixed-layer CIN
- -77 J/kg
- Mixed-layer LCL
- 654 m above ground
- 0-6 km bulk shear
- 47 kt
- 0-1 km storm-relative helicity
- 182 m²/s²
- 0-3 km storm-relative helicity
- 199 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.2
The text
As transmitted.
369 WWUS20 KWNS 091935 SEL8 SPC WW 091935 NCZ000-VAZ000-100400- URGENT - IMMEDIATE BROADCAST REQUESTED Severe Thunderstorm Watch Number 78 NWS Storm Prediction Center Norman OK 335 PM EDT Fri Apr 9 2021 The NWS Storm Prediction Center has issued a * Severe Thunderstorm Watch for portions of Northern North Carolina Southern Virginia * Effective this Friday afternoon from 335 PM until Midnight EDT. * Primary threats include... Scattered damaging wind gusts to 70 mph possible Scattered large hail events to 1.5 inches in diameter possible A tornado or two possible SUMMARY...Scattered thunderstorms are forming and beginning to move east of the higher terrain in southwestern Virginia, and additional storm development is expected this afternoon along a stalled front farther east across northern North Carolina and southern Virginia. The storm environment will favor a mix of multicell clusters and supercells, with the attendant threats for large hail and damaging winds. An isolated tornado cannot be ruled out with supercells moving along the front. The severe thunderstorm watch area is approximately along and 30 statute miles north and south of a line from 60 miles west of Danville VA to 75 miles east of Roanoke Rapids NC. For a complete depiction of the watch see the associated watch outline update (WOUS64 KWNS WOU8). PRECAUTIONARY/PREPAREDNESS ACTIONS... REMEMBER...A Severe Thunderstorm Watch means conditions are favorable for severe thunderstorms in and close to the watch area. Persons in these areas should be on the lookout for threatening weather conditions and listen for later statements and possible warnings. Severe thunderstorms can and occasionally do produce tornadoes. && OTHER WATCH INFORMATION...CONTINUE...WW 76...WW 77... AVIATION...A few severe thunderstorms with hail surface and aloft to 1.5 inches. Extreme turbulence and surface wind gusts to 60 knots. A few cumulonimbi with maximum tops to 450. Mean storm motion vector 27020. ...Thompson
SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Apr 9, 1:37 PM EDT | Mesoscale Discussion | SPC | Alleghany, Ashe, Stokes, Surry, Warren, Wilkes | 113 min |
| Apr 9, 6:23 PM EDT | Mesoscale Discussion | SPC | Bertie, Camden, Caswell, Chowan, Currituck, Edgecombe and 14 more | 97 min |
Nearby
Severe Thunderstorm Watches in Virginia, 2021Severe Thunderstorm Watches in North Carolina, 2021Every severe thunderstorm watch 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.