Alert archive / North Carolina / Tornado Watches in 2013

Tornado Watch 103

April 12, 201331 counties in North Carolina

The Storm Prediction Center issued this tornado watch at Apr 12, 2013, 2:57 AM EDT for 31 counties in North Carolina. It was in force for 6 hr.

The area

The outline as issued.

The facts

Issued: Apr 12, 2013, 2:57 AM EDT (06:57 UTC)
Expired: Apr 12, 2013, 8:36 AM EDT
In force: 6 hr
Issued by: the Storm Prediction Center
Largest hail expected: 0.5 in
Strongest gust expected: 60 kt

All 31 counties

Alamance County, NC, Anson County, NC, Chatham County, NC, Cumberland County, NC, Davidson County, NC, Durham County, NC, Edgecombe County, NC, Forsyth County, NC, Franklin County, NC, Granville County, NC, Guilford County, NC, Halifax County, NC, Harnett County, NC, Hoke County, NC, Johnston County, NC, Lee County, NC, Montgomery County, NC, Moore County, NC, Nash County, NC, Orange County, NC, Person County, NC, Randolph County, NC, Richmond County, NC, Sampson County, NC, Scotland County, NC, Stanly County, NC, Vance County, NC, Wake County, NC, Warren County, NC, Wayne County, NC, Wilson County, NC

The radar

The Raleigh/Durham radar (KRAX), 81 km from the middle of the area, began a volume at 06:59 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: 30%
One or more gusts of 65 knots or more: 30%
Ten or more severe hail reports: 10%
One or more hailstones of 2 inches or more: 5%
Six or more combined severe hail and wind reports: 60%

Warnings issued inside it

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

Issued	Product	Office	Counties	Lasted
Apr 12, 3:55 AM EDT	Severe Thunderstorm Warning	RAH	Davidson, Forsyth	50 min
Apr 12, 5:20 AM EDT	Severe Thunderstorm Warning	RAH	Chatham, Montgomery, Moore, Randolph	40 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

Greensboro/Hi Pt, NC (KGSO), launched 00:00Z, 7.0 hours before the alert went out and 56 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: 29 J/kg
Mixed-layer CIN: -31 J/kg
Mixed-layer LCL: 1610 m above ground
0-6 km bulk shear: 26 kt
0-1 km storm-relative helicity: 56 m²/s²
0-3 km storm-relative helicity: 100 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

595 
WWUS20 KWNS 120654
SEL3  
SPC WW 120654
NCZ000-121300-

URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 103
NWS STORM PREDICTION CENTER NORMAN OK
255 AM EDT FRI APR 12 2013

THE NWS STORM PREDICTION CENTER HAS ISSUED A
TORNADO WATCH FOR PORTIONS OF 

       CENTRAL NORTH CAROLINA

EFFECTIVE THIS FRIDAY MORNING FROM 255 AM UNTIL 900 AM EDT.

TORNADOES...HAIL TO 0.5 INCH IN DIAMETER...THUNDERSTORM WIND
GUSTS TO 70 MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE
AREAS.

THE TORNADO WATCH AREA IS APPROXIMATELY ALONG AND 65 STATUTE
MILES NORTH AND SOUTH OF A LINE FROM 45 MILES SOUTHWEST OF
GREENSBORO NORTH CAROLINA TO 20 MILES SOUTHEAST OF ROCKY MOUNT
NORTH CAROLINA.  FOR A COMPLETE DEPICTION OF THE WATCH SEE THE
ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU3).

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 101...WW 102...

DISCUSSION...SCATTERED THUNDERSTORMS ARE MOVING ACROSS WESTERN
NC...AND WILL TRAVERSE THE WATCH AREA DURING THE NEXT SEVERAL HOURS.
 SUFFICIENT AND INCREASING LOW/MID WIND SHEAR COMBINED WITH 500-1000
J/KG OF CAPE WILL PROVIDE A CONDITIONAL RISK OF SEVERE STORMS
OVERNIGHT.  LOCALLY DAMAGING WINDS OR A TORNADO ARE THE PRIMARY
RISKS.

AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL
SURFACE AND ALOFT TO 0.5 INCH. EXTREME TURBULENCE AND SURFACE
WIND GUSTS TO 60 KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO
450. MEAN STORM MOTION VECTOR 24035.


...HART

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Apr 11, 8:24 PM EDT	Tornado Watch	SPC	Alexander, Burke, Cabarrus, Caldwell, Catawba, Cleveland and 10 more	8 hr
Apr 11, 9:19 PM EDT	Mesoscale Discussion	SPC	Cherokee, Graham, Haywood, Jackson, Macon, Madison and 1 more	86 min
Apr 11, 10:52 PM EDT	Mesoscale Discussion	SPC	Cleveland, Henderson, Polk, Rutherford, Transylvania	83 min
Apr 12, 12:46 AM EDT	Mesoscale Discussion	SPC	Columbus	89 min
Apr 12, 1:06 AM EDT	Tornado Watch	SPC	Bladen, Brunswick, Columbus, New Hanover, Pender, Robeson	6 hr
Apr 12, 1:58 AM EDT	Mesoscale Discussion	SPC	Alamance, Bertie, Caswell, Chatham, Cumberland, Davidson and 34 more	92 min
Apr 12, 4:00 AM EDT	Mesoscale Discussion	SPC	Bladen, Brunswick, Columbus, New Hanover, Pender, Robeson and 1 more	90 min
Apr 12, 5:21 AM EDT	Tornado Watch	SPC	Northampton	3 hr
Apr 12, 7:25 AM EDT	Mesoscale Discussion	SPC	Edgecombe, Franklin, Greene, Halifax, Johnston, Nash and 6 more	65 min
Apr 12, 2:34 PM EDT	Mesoscale Discussion	SPC	Beaufort, Bertie, Bladen, Camden, Chowan, Columbus and 15 more	116 min

Nearby

Tornado Watches in North Carolina, 2013 Every tornado watch in 2013

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.