Alert archive / North Carolina / Tornado Watches in 2018

Tornado Watch 378

September 15, 201810 counties in North Carolina

The Storm Prediction Center issued this tornado watch at Sep 15, 2018, 11:01 PM EDT for 10 counties in North Carolina. It was in force for 8 hr.

The area

The outline as issued.

The facts

Issued
Sep 15, 2018, 11:01 PM EDT (03:01 UTC)
Expired
Sep 16, 2018, 6:57 AM EDT
In force
8 hr
Issued by
the Storm Prediction Center
Strongest gust expected
60 kt

Counties Bladen County, NC, Brunswick County, NC, Columbus County, NC, Cumberland County, NC, Hoke County, NC, New Hanover County, NC, Pender County, NC, Robeson County, NC, Sampson County, NC, Scotland County, NC

The radar

The Wilmington radar (KLTX), 73 km from the middle of the area, began a volume at 03:02 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
30%
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

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

IssuedProductOfficeCountiesLasted
Sep 15, 11:53 PM EDTTornado WarningILMNew Hanover15 min
Sep 16, 12:23 AM EDTTornado WarningILMNew Hanover8 min
Sep 16, 12:26 AM EDTTornado WarningILMBrunswick, New Hanover34 min
Sep 16, 12:55 AM EDTTornado WarningILMBrunswick, New Hanover20 min
Sep 16, 1:51 AM EDTTornado WarningILMBrunswick, New Hanover24 min
Sep 16, 3:40 AM EDTFlash Flood Warning EmergencyRAHSampson6 hr
Sep 16, 5:23 AM EDTFlash Flood WarningILMBladen, Brunswick, Columbus, New Hanover, Pender, Robeson8 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, 3.0 hours before the alert went out and 133 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 2018-09-16Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 733 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 2018-09-16The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 182 square meters per square second.193958Sfc1 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
733 J/kg
Mixed-layer CIN
-4 J/kg
Mixed-layer LCL
609 m above ground
0-6 km bulk shear
31 kt
0-1 km storm-relative helicity
182 m²/s²
0-3 km storm-relative helicity
186 m²/s²
Significant tornado parameter
0.4
Supercell composite
4.2

Open this sounding in Storm Lab

The text

As transmitted.

623 
WWUS20 KWNS 160258
SEL8  
SPC WW 160258
NCZ000-CWZ000-161100-

URGENT - IMMEDIATE BROADCAST REQUESTED
Tornado Watch Number 378
NWS Storm Prediction Center Norman OK
1100 PM EDT Sat Sep 15 2018

The NWS Storm Prediction Center has issued a

* Tornado Watch for portions of 
  Southeast North Carolina
  Coastal Waters

* Effective this Saturday night and Sunday morning from 1100 PM
  until 700 AM EDT.

* Primary threats include...
  A couple tornadoes possible

SUMMARY...The winds above the surface remain relatively strong in
association with Tropical Storm Florence. This, in conjunction with
a very moist air mass, will continue to support inland-spreading
supercells capable of brief tornadoes.

The tornado watch area is approximately along and 45 statute miles
east and west of a line from 15 miles north of Fayetteville NC to 30
miles south of Wilmington NC. For a complete depiction of the watch
see the associated watch outline update (WOUS64 KWNS WOU8).

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 377...

AVIATION...Tornadoes and a few severe thunderstorms with hail
surface and aloft to 0 inches. Extreme turbulence and surface wind
gusts to 60 knots. A few cumulonimbi with maximum tops to 500. Mean
storm motion vector 13050.

...Guyer

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Sep 15, 9:14 PM EDTMesoscale DiscussionSPCBladen, Brunswick, Columbus, Cumberland, Hoke, New Hanover and 4 more2 hr
Sep 15, 11:59 PM EDTMesoscale DiscussionSPCBladen, Brunswick, Columbus, New Hanover, Pender, Robeson3 hr
Sep 16, 3:23 AM EDTMesoscale DiscussionSPCBladen, Brunswick, Columbus, Cumberland, Duplin, Hoke and 6 more2 hr
Sep 16, 6:32 AM EDTMesoscale DiscussionSPCBladen, Brunswick, Columbus, Cumberland, Duplin, Hoke and 6 more88 min
Sep 16, 6:55 AM EDTTornado WatchSPCAnson, Bladen, Brunswick, Columbus, Cumberland, Hoke and 6 more16 hr
Sep 16, 11:22 AM EDTMesoscale DiscussionSPCBladen, Brunswick, Columbus, Hoke, Richmond, Robeson and 1 more113 min
Sep 16, 3:42 PM EDTMesoscale DiscussionSPCAnson, Hoke, Richmond, Robeson, Scotland93 min
Sep 16, 4:14 PM EDTTornado WatchSPCAnson, Cumberland, Harnett, Hoke, Lee, Montgomery and 4 more7 hr

Nearby

Tornado Watches in North Carolina, 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.