Alert archive / North Carolina / Tornado Watches in 2018

Tornado Watch 371

September 13, 201815 counties in North Carolina

The Storm Prediction Center issued this tornado watch at Sep 13, 2018, 7:08 AM EDT for 15 counties in North Carolina. It was in force for 14 hr.

The area

The outline as issued.

The facts

Issued: Sep 13, 2018, 7:08 AM EDT (11:08 UTC)
Expired: Sep 13, 2018, 9:00 PM EDT
In force: 14 hr
Issued by: the Storm Prediction Center
Largest hail expected: 0.5 in
Strongest gust expected: 60 kt

Counties Beaufort County, NC, Carteret County, NC, Craven County, NC, Dare County, NC, Duplin County, NC, Greene County, NC, Hyde County, NC, Jones County, NC, Lenoir County, NC, Martin County, NC, Onslow County, NC, Pamlico County, NC, Pitt County, NC, Tyrrell County, NC, Washington County, NC

The radar

The Morehead City radar (KMHX), 84 km from the middle of the area, began a volume at 11:12 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: 50%
One or more EF2 to EF5 tornadoes: 10%
Ten or more severe wind reports: 5%
One or more gusts of 65 knots or more: 5%
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: 20%

Warnings issued inside it

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

Issued	Product	Office	Counties	Lasted
Sep 13, 11:00 AM EDT	Tornado Warning	MHX	Hyde	15 min
Sep 13, 11:19 AM EDT	Tornado Warning	MHX	Beaufort, Pamlico	26 min
Sep 13, 4:38 PM EDT	Flash Flood Warning	MHX	Carteret	10 hr
Sep 13, 5:34 PM EDT	Flash Flood Warning	MHX	Dare	8 hr
Sep 13, 6:14 PM EDT	Tornado Warning	MHX	Dare	16 min
Sep 13, 7:41 PM EDT	Flash Flood Warning	MHX	Craven, Jones, Pamlico	7 hr
Sep 13, 7:44 PM EDT	Tornado Warning	MHX	Carteret, Craven	17 min
Sep 13, 8:49 PM EDT	Tornado Warning	MHX	Dare, Hyde	26 min
Sep 13, 8:51 PM EDT	Flash Flood Warning	MHX	Jones, Onslow	31 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

Newport, NC (KMHX), launched 00:00Z, 11.1 hours before the alert went out and 84 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 1114 J/kg
Mixed-layer CIN: -5 J/kg
Mixed-layer LCL: 824 m above ground
0-6 km bulk shear: 10 kt
0-1 km storm-relative helicity: -21 m²/s²
0-3 km storm-relative helicity: 28 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

210 
WWUS20 KWNS 131104
SEL1  
SPC WW 131104
NCZ000-CWZ000-140100-

URGENT - IMMEDIATE BROADCAST REQUESTED
Tornado Watch Number 371
NWS Storm Prediction Center Norman OK
705 AM EDT Thu Sep 13 2018

The NWS Storm Prediction Center has issued a

* Tornado Watch for portions of 
  Eastern North Carolina
  Coastal Waters

* Effective this Thursday morning and evening from 705 AM until
  900 PM EDT.

* Primary threats include...
  A few tornadoes possible

SUMMARY...Outer convective bands with hurricane Florence will
gradually spread inland across the North Carolina coast this
morning, and continue across eastern North Carolina through the
afternoon/evening.  Supercells and a few tornadoes will be possible
with the outer convective bands.

The tornado watch area is approximately along and 50 statute miles
east and west of a line from 85 miles northeast of New Bern NC to 30
miles southeast of Jacksonville NC. For a complete depiction of the
watch see the associated watch outline update (WOUS64 KWNS WOU1).

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.

&&

AVIATION...Tornadoes and a few severe thunderstorms with hail
surface and aloft to 0.5 inches. Extreme turbulence and surface wind
gusts to 60 knots. A few cumulonimbi with maximum tops to 500. Mean
storm motion vector 06055.

...Thompson

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Sep 13, 3:46 AM EDT	Mesoscale Discussion	SPC	Beaufort, Bladen, Brunswick, Carteret, Columbus, Craven and 16 more	2 hr
Sep 13, 3:29 PM EDT	Mesoscale Discussion	SPC	Beaufort, Bertie, Bladen, Camden, Carteret, Chowan and 33 more	2 hr

Nearby

Tornado Watches in North Carolina, 2018 Every 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.