Alert archive / Virginia / Tornado Watches in 2021

Tornado Watch 43

March 18, 20219 counties in North Carolina; 17 counties in Virginia

The Storm Prediction Center issued this tornado watch at Mar 18, 2021, 5:09 PM EDT for 9 counties in North Carolina; 17 counties in Virginia. It was in force for 6 hr.

The area

The outline as issued.

The facts

Issued
Mar 18, 2021, 5:09 PM EDT (21:09 UTC)
Expired
Mar 18, 2021, 11:00 PM EDT
In force
6 hr
Issued by
the Storm Prediction Center
Largest hail expected
1 in
Strongest gust expected
55 kt
All 26 counties

Bertie County, NC, Camden County, NC, Chowan County, NC, Currituck County, NC, Gates County, NC, Hertford County, NC, Northampton County, NC, Pasquotank County, NC, Perquimans County, NC, Brunswick County, VA, City of Chesapeake, VA, City of Emporia, VA, City of Franklin, VA, City of Hampton, VA, City of Newport News, VA, City of Norfolk, VA, City of Portsmouth, VA, City of Suffolk, VA, City of Virginia Beach, VA, Greensville County, VA, Isle of Wight County, VA, Lunenburg County, VA, Mecklenburg County, VA, Southampton County, VA, Surry County, VA, Sussex County, VA

The radar

The Norfolk radar (KAKQ), 34 km from the middle of the area, began a volume at 21:09 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
40%
One or more EF2 to EF5 tornadoes
30%
Ten or more severe wind reports
20%
One or more gusts of 65 knots or more
10%
Ten or more severe hail reports
10%
One or more hailstones of 2 inches or more
10%
Six or more combined severe hail and wind reports
40%

Warnings issued inside it

14 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.

IssuedProductOfficeCountiesLasted
Mar 18, 5:11 PM EDTSevere Thunderstorm WarningAKQSouthampton, Sussex34 min
Mar 18, 5:18 PM EDTTornado WarningAKQNorthampton27 min
Mar 18, 5:31 PM EDTTornado WarningAKQGreensville, Southampton, Sussex29 min
Mar 18, 5:37 PM EDTSevere Thunderstorm WarningAKQIsle of Wight, Southampton, Surry38 min
Mar 18, 5:48 PM EDTSevere Thunderstorm WarningAKQSouthampton, Sussex27 min
Mar 18, 6:00 PM EDTSevere Thunderstorm WarningAKQIsle of Wight, York, City of Hampton, City of Newport News, City of Poquoson45 min
Mar 18, 6:17 PM EDTSevere Thunderstorm WarningAKQIsle of Wight, Southampton28 min
Mar 18, 7:28 PM EDTSevere Thunderstorm WarningAKQPrince George, Surry, Sussex47 min
Mar 18, 7:45 PM EDTSevere Thunderstorm WarningAKQBrunswick, Dinwiddie, Greensville, Lunenburg, Mecklenburg, City of Emporia30 min
Mar 18, 7:59 PM EDTTornado WarningAKQBrunswick, Greensville, Mecklenburg31 min
Mar 18, 8:03 PM EDTSevere Thunderstorm WarningAKQCharles City, James City, Prince George, Surry, City of Williamsburg42 min
Mar 18, 8:15 PM EDTSevere Thunderstorm WarningAKQNorthampton30 min
Mar 18, 8:28 PM EDTSevere Thunderstorm WarningAKQGreensville, Southampton, Sussex, City of Emporia32 min
Mar 18, 10:05 PM EDTSevere Thunderstorm WarningAKQCity of Norfolk, City of Portsmouth, City of Virginia Beach25 min

Discussions around it

SPC mesoscale discussions over the same counties from four hours before the watch to its end.

The nearest sounding before it

Wallops Is Stn, VA (KWAL), launched 12:00Z, 9.2 hours before the alert went out and 208 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.

Skew-T log-pSkew-T log-p diagram, Wallops Is Stn, VA at 12:00Z on 2021-03-18Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Wallops Is Stn, VA at 12:00Z on 2021-03-18The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 207 square meters per square second.19395878Sfc1 km3 km6 km9 kmRMLM
The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.
Mixed-layer CAPE
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
535 m above ground
0-6 km bulk shear
45 kt
0-1 km storm-relative helicity
207 m²/s²
0-3 km storm-relative helicity
300 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

614 
WWUS20 KWNS 182103
SEL3  
SPC WW 182103
NCZ000-VAZ000-CWZ000-190100-

URGENT - IMMEDIATE BROADCAST REQUESTED
Tornado Watch Number 43
NWS Storm Prediction Center Norman OK
505 PM EDT Thu Mar 18 2021

The NWS Storm Prediction Center has issued a

* Tornado Watch for portions of 
  Northeast North Carolina
  Southeast Virginia
  Coastal Waters

* Effective this Thursday afternoon and evening from 505 PM until
  900 PM EDT.

* Primary threats include...
  A couple intense tornadoes possible
  Isolated damaging wind gusts to 65 mph possible

SUMMARY...A supercell or two may develop along the North Carolina
and Virginia border within a favorable tornado environment.

The tornado watch area is approximately along and 40 statute miles
north and south of a line from 20 miles northwest of Roanoke Rapids
NC to 20 miles north northeast of Elizabeth City NC. For a complete
depiction of the watch see the associated watch outline update
(WOUS64 KWNS WOU3).

PRECAUTIONARY/PREPAREDNESS ACTIONS...

REMEMBER...A Tornado Watch means conditions are favorable for
tornadoes and 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.

&&

OTHER WATCH INFORMATION...CONTINUE...WW 40...WW 41...WW 42...

AVIATION...Tornadoes and a few severe thunderstorms with hail
surface and aloft to 1 inch. Extreme turbulence and surface wind
gusts to 55 knots. A few cumulonimbi with maximum tops to 450. Mean
storm motion vector 24035.

...Grams

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Mar 18, 10:34 AM EDTMesoscale DiscussionSPCCabarrus, Cleveland, Gaston, Lincoln, Mecklenburg, Rowan and 1 more2 hr
Mar 18, 2:08 PM EDTTornado WatchSPCCabarrus, Cleveland, Gaston, Lincoln, Mecklenburg, Union4 hr
Mar 18, 3:10 PM EDTMesoscale DiscussionSPCCabarrus, Cleveland, Gaston, Lincoln, Mecklenburg, Rutherford and 2 more3 hr
Mar 18, 4:45 PM EDTTornado WatchSPCAlamance, Anson, Chatham, Cumberland, Davidson, Durham and 20 more4 hr
Mar 18, 5:57 PM EDTMesoscale DiscussionSPCAlamance, Anson, Beaufort, Bertie, Cabarrus, Camden and 45 more63 min
Mar 18, 7:49 PM EDTMesoscale DiscussionSPCAlamance, Anson, Chatham, Cumberland, Durham, Edgecombe and 21 more56 min
Mar 18, 2:25 PM EDTMesoscale DiscussionSPCBland, Buchanan, Dickenson, Russell, Tazewell, Washington and 2 more3 hr

Nearby

Tornado Watches in Virginia, 2021Tornado Watches in North Carolina, 2021Every tornado 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.