Alert archive / North Carolina / Tornado Watches in 2018

Tornado Watch 377

September 15, 201810 counties in North Carolina

The Storm Prediction Center issued this tornado watch at Sep 15, 2018, 4:38 PM EDT for 10 counties in North Carolina. It was in force for 6 hr.

The area

The outline as issued.

The facts

Issued
Sep 15, 2018, 4:38 PM EDT (20:38 UTC)
Expired
Sep 15, 2018, 11:00 PM EDT
In force
6 hr
Issued by
the Storm Prediction Center
Largest hail expected
0.5 in
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), 59 km from the middle of the area, began a volume at 20:39 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
20%
Ten or more severe wind reports
20%
One or more gusts of 65 knots or more
10%
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
30%

Warnings issued inside it

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

IssuedProductOfficeCountiesLasted
Sep 15, 6:01 PM EDTTornado WarningILMNew Hanover, Pender14 min
Sep 15, 7:12 PM EDTTornado WarningILMNew Hanover, Pender33 min
Sep 15, 8:06 PM EDTTornado WarningILMNew Hanover9 min
Sep 15, 8:28 PM EDTTornado WarningILMNew Hanover17 min
Sep 15, 8:48 PM EDTTornado WarningILMNew Hanover12 min
Sep 15, 9:23 PM EDTTornado WarningILMNew Hanover, Pender22 min
Sep 15, 9:49 PM EDTTornado WarningILMPender11 min
Sep 15, 9:55 PM EDTFlash Flood WarningILMBladen, Brunswick, Columbus, New Hanover, Pender, Robeson8 hr
Sep 15, 10:27 PM EDTTornado WarningILMPender18 min
Sep 15, 10:31 PM EDTTornado WarningILMPender14 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 12:00Z, 8.6 hours before the alert went out and 146 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 12:00Z on 2018-09-15Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 711 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 12:00Z on 2018-09-15The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 192 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
711 J/kg
Mixed-layer CIN
-4 J/kg
Mixed-layer LCL
721 m above ground
0-6 km bulk shear
24 kt
0-1 km storm-relative helicity
192 m²/s²
0-3 km storm-relative helicity
172 m²/s²
Significant tornado parameter
0.0
Supercell composite
2.2

Open this sounding in Storm Lab

The text

As transmitted.

263 
WWUS20 KWNS 152034
SEL7  
SPC WW 152034
NCZ000-CWZ000-160300-

URGENT - IMMEDIATE BROADCAST REQUESTED
Tornado Watch Number 377
NWS Storm Prediction Center Norman OK
435 PM EDT Sat Sep 15 2018

The NWS Storm Prediction Center has issued a

* Tornado Watch for portions of 
  Southeastern North Carolina
  Coastal Waters

* Effective this Saturday afternoon and evening from 435 PM until
  1100 PM EDT.

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

SUMMARY...Bands of convection pivoting inland across coastal areas
into southeastern North Carolina, on the outer periphery of
Florence, may continue to pose a risk for a couple of tornadoes, as
well as potentially damaging surface gusts, through this evening.

The tornado watch area is approximately along and 35 statute miles
either side of a line from 15 miles west of Fayetteville NC to 45
miles south southeast of Wilmington NC. For a complete depiction of
the watch see the associated watch outline update (WOUS64 KWNS
WOU7).

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...This tornado watch replaces tornado
watch number 376. Watch number 376 will not be in effect after
435 PM EDT. 

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 300. Mean
storm motion vector 14035.

...Kerr

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Sep 14, 8:01 PM EDTMesoscale DiscussionSPCBeaufort, Carteret, Craven, Cumberland, Dare, Duplin and 18 more119 min
Sep 14, 10:25 PM EDTMesoscale DiscussionSPCBladen, Brunswick, Carteret, Columbus, Craven, Cumberland and 11 more95 min
Sep 14, 11:03 PM EDTTornado WatchSPCBladen, Brunswick, Carteret, Columbus, Craven, Cumberland and 12 more8 hr
Sep 15, 2:59 AM EDTMesoscale DiscussionSPCBladen, Brunswick, Carteret, Columbus, Craven, Cumberland and 12 more91 min
Sep 15, 6:15 AM EDTMesoscale DiscussionSPCBeaufort, Bladen, Brunswick, Carteret, Columbus, Craven and 16 more90 min
Sep 15, 6:59 AM EDTTornado WatchSPCBladen, Brunswick, Columbus, Cumberland, Duplin, Greene and 14 more10 hr
Sep 15, 12:01 PM EDTMesoscale DiscussionSPCBladen, Brunswick, Columbus, Craven, Cumberland, Duplin and 9 more119 min
Sep 15, 3:26 PM EDTMesoscale DiscussionSPCPender64 min

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.