Alert archive / North Carolina / Severe Thunderstorm Watches in 2012

Severe Thunderstorm Watch 585

August 19, 20124 states

The Storm Prediction Center issued this severe thunderstorm watch at Aug 19, 2012, 10:33 AM EDT for 4 states. It was in force for 7 hr.

The area

The outline as issued.

The facts

Issued
Aug 19, 2012, 10:33 AM EDT (14:33 UTC)
Expired
Aug 19, 2012, 5:06 PM EDT
In force
7 hr
Issued by
the Storm Prediction Center
Largest hail expected
1 in
Strongest gust expected
60 kt
All 59 counties

Bryan County, GA, Chatham County, GA, Effingham County, GA, Liberty County, GA, Long County, GA, McIntosh County, GA, Beaufort County, NC, Bertie County, NC, Bladen County, NC, Brunswick County, NC, Camden County, NC, Carteret County, NC, Chowan County, NC, Columbus County, NC, Craven County, NC, Cumberland County, NC, Currituck County, NC, Dare County, NC, Duplin County, NC, Edgecombe County, NC, Gates County, NC, Greene County, NC, Hertford County, NC, Hyde County, NC, Johnston County, NC, Jones County, NC, Lenoir County, NC, Martin County, NC, New Hanover County, NC, Onslow County, NC, Pamlico County, NC, Pasquotank County, NC, Pender County, NC, Perquimans County, NC, Pitt County, NC, Robeson County, NC, Sampson County, NC, Tyrrell County, NC, Washington County, NC, Wayne County, NC, Wilson County, NC, Beaufort County, SC, Berkeley County, SC, Charleston County, SC, Colleton County, SC, Dillon County, SC, Dorchester County, SC, Florence County, SC, Georgetown County, SC, Hampton County, SC, Horry County, SC, Jasper County, SC, Marion County, SC, Williamsburg County, SC, City of Chesapeake, VA, City of Norfolk, VA, City of Portsmouth, VA, City of Suffolk, VA, City of Virginia Beach, VA

The radar

The Wilmington radar (KLTX), 75 km from the middle of the area, began a volume at 14:34 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
20%
One or more EF2 to EF5 tornadoes
5%
Ten or more severe wind reports
30%
One or more gusts of 65 knots or more
30%
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
70%

Warnings issued inside it

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

IssuedProductOfficeCountiesLasted
Aug 19, 10:34 AM EDTSevere Thunderstorm WarningAKQBertie, Hertford, Northampton41 min
Aug 19, 11:14 AM EDTSevere Thunderstorm WarningCHSBulloch, Effingham46 min
Aug 19, 11:35 AM EDTSevere Thunderstorm WarningAKQChowan, Gates, Hertford, Perquimans40 min
Aug 19, 2:11 PM EDTTornado WarningMHXDare34 min
Aug 19, 2:20 PM EDTTornado WarningMHXDare25 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, 2.6 hours before the alert went out and 120 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 2012-08-19Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1089 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 2012-08-19The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 38 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
1089 J/kg
Mixed-layer CIN
-28 J/kg
Mixed-layer LCL
821 m above ground
0-6 km bulk shear
39 kt
0-1 km storm-relative helicity
38 m²/s²
0-3 km storm-relative helicity
75 m²/s²
Significant tornado parameter
0.2
Supercell composite
1.7

Open this sounding in Storm Lab

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Aug 19, 9:53 AM EDTMesoscale DiscussionSPCBeaufort, Bertie, Bladen, Brunswick, Camden, Carteret and 25 more97 min
Aug 19, 1:38 PM EDTMesoscale DiscussionSPCBeaufort, Brunswick, Camden, Carteret, Craven, Currituck and 10 more97 min

Nearby

Severe Thunderstorm Watches in North Carolina, 2012Severe Thunderstorm Watches in South Carolina, 2012Severe Thunderstorm Watches in Georgia, 2012Every severe thunderstorm watch in 2012

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.