Alert archive / North Carolina / Tornado Watches in 2018

Tornado Watch 55

April 15, 201823 counties in North Carolina; 13 counties in Virginia

The Storm Prediction Center issued this tornado watch at Apr 15, 2018, 9:32 PM EDT for 23 counties in North Carolina; 13 counties in Virginia. It was in force for 4 hr.

The area

The outline as issued.

The facts

Issued
Apr 15, 2018, 9:32 PM EDT (01:32 UTC)
Expired
Apr 16, 2018, 1:48 AM EDT
In force
4 hr
Issued by
the Storm Prediction Center
Largest hail expected
1 in
Strongest gust expected
60 kt
All 36 counties

Beaufort County, NC, Bertie County, NC, Carteret County, NC, Chowan County, NC, Craven County, NC, Duplin County, NC, Edgecombe County, NC, Gates County, NC, Greene County, NC, Halifax County, NC, Hertford County, NC, Jones County, NC, Lenoir County, NC, Martin County, NC, Nash County, NC, Northampton County, NC, Onslow County, NC, Pamlico County, NC, Perquimans County, NC, Pitt County, NC, Washington County, NC, Wayne County, NC, Wilson County, NC, Charles City County, VA, City of Colonial Heights, VA, City of Emporia, VA, City of Franklin, VA, City of Hopewell, VA, City of Petersburg, VA, City of Suffolk, VA, Greensville County, VA, Isle of Wight County, VA, Prince George County, VA, Southampton County, VA, Surry County, VA, Sussex County, VA

The radar

The Norfolk radar (KAKQ), 101 km from the middle of the area, began a volume at 01:35 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
20%
Ten or more severe wind reports
40%
One or more gusts of 65 knots or more
20%
Ten or more severe hail reports
5%
One or more hailstones of 2 inches or more
5%
Six or more combined severe hail and wind reports
50%

Warnings issued inside it

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

IssuedProductOfficeCountiesLasted
Apr 15, 9:46 PM EDTSevere Thunderstorm WarningRAHCumberland, Harnett, Johnston, Sampson, Wake, Wayne44 min
Apr 15, 10:22 PM EDTSevere Thunderstorm WarningRAHFranklin, Granville, Nash, Vance, Wake, Warren53 min
Apr 15, 10:26 PM EDTSevere Thunderstorm WarningRAHJohnston, Nash, Sampson, Wake, Wayne, Wilson64 min
Apr 15, 10:30 PM EDTSevere Thunderstorm WarningMHXDuplin60 min
Apr 15, 11:23 PM EDTSevere Thunderstorm WarningRAHEdgecombe, Franklin, Halifax, Nash, Warren52 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

Newport, NC (KMHX), launched 00:00Z, 1.5 hours before the alert went out and 145 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, Newport, NC at 00:00Z on 2018-04-16Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 584 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Newport, NC at 00:00Z on 2018-04-16The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 269 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
584 J/kg
Mixed-layer CIN
-6 J/kg
Mixed-layer LCL
610 m above ground
0-6 km bulk shear
48 kt
0-1 km storm-relative helicity
269 m²/s²
0-3 km storm-relative helicity
298 m²/s²
Significant tornado parameter
0.8
Supercell composite
5.0

Open this sounding in Storm Lab

The text

As transmitted.

095 
WWUS20 KWNS 160130
SEL5  
SPC WW 160130
NCZ000-VAZ000-CWZ000-160700-

URGENT - IMMEDIATE BROADCAST REQUESTED
Tornado Watch Number 55
NWS Storm Prediction Center Norman OK
935 PM EDT Sun Apr 15 2018

The NWS Storm Prediction Center has issued a

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

* Effective this Sunday night and Monday morning from 935 PM
  until 300 AM EDT.

* Primary threats include...
  A couple tornadoes possible
  Scattered damaging wind gusts to 70 mph possible

SUMMARY...A line of strong/severe thunderstorms over central NC will
track northeastward across the watch area.  Very strong winds just
above the surface will promote a risk of damaging wind gusts or
brief tornadoes along the leading edge of the squall line.

The tornado watch area is approximately along and 35 statute miles
east and west of a line from 60 miles northeast of Roanoke Rapids NC
to 15 miles south southeast of Jacksonville NC. For a complete
depiction of the watch see the associated watch outline update
(WOUS64 KWNS WOU5).

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 53...WW 54...

AVIATION...Tornadoes and a few severe thunderstorms with hail
surface and aloft to 1 inch. Extreme turbulence and surface wind
gusts to 60 knots. A few cumulonimbi with maximum tops to 450. Mean
storm motion vector 21040.

...Hart

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Apr 15, 8:31 PM EDTMesoscale DiscussionSPCAlamance, Bladen, Brunswick, Chatham, Columbus, Cumberland and 29 more89 min
Apr 15, 9:07 PM EDTMesoscale DiscussionSPCBeaufort, Bertie, Camden, Chowan, Craven, Edgecombe and 14 more83 min
Apr 15, 11:19 PM EDTMesoscale DiscussionSPCBeaufort, Bertie, Camden, Carteret, Chowan, Craven and 27 more86 min

Nearby

Tornado Watches in North Carolina, 2018Tornado Watches in Virginia, 2018Every tornado watch in 2018

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.