Alert archive / North Carolina / Mesoscale Discussions in 2012

Mesoscale Discussion 1969

September 18, 201246 counties in North Carolina

The Storm Prediction Center issued this mesoscale discussion at Sep 18, 2012, 4:11 PM EDT for 46 counties in North Carolina. It was in force for 94 min.

The area

The outline as issued.

The facts

Issued
Sep 18, 2012, 4:11 PM EDT (20:11 UTC)
Expired
Sep 18, 2012, 5:45 PM EDT
In force
94 min
Issued by
the Storm Prediction Center
All 46 counties

Alamance County, NC, Anson County, NC, Beaufort County, NC, Carteret County, NC, Chatham County, NC, Craven County, NC, Cumberland County, NC, Dare County, NC, Davidson County, NC, Duplin County, NC, Durham County, NC, Edgecombe County, NC, Forsyth County, NC, Franklin County, NC, Granville County, NC, Greene County, NC, Guilford County, NC, Halifax County, NC, Harnett County, NC, Hoke County, NC, Hyde County, NC, Johnston County, NC, Jones County, NC, Lee County, NC, Lenoir County, NC, Martin County, NC, Montgomery County, NC, Moore County, NC, Nash County, NC, Onslow County, NC, Orange County, NC, Pamlico County, NC, Person County, NC, Pitt County, NC, Randolph County, NC, Richmond County, NC, Sampson County, NC, Scotland County, NC, Stanly County, NC, Tyrrell County, NC, Vance County, NC, Wake County, NC, Warren County, NC, Washington County, NC, Wayne County, NC, Wilson County, NC

The radar

The Raleigh/Durham radar (KRAX), 86 km from the middle of the area, began a volume at 20:13 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.

The nearest sounding before it

Newport, NC (KMHX), launched 12:00Z, 8.2 hours before the alert went out and 109 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 2012-09-18Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1124 joules per kilogram.LCLEL10008507005003002001001 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 2012-09-18The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 176 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
1124 J/kg
Mixed-layer CIN
0 J/kg
Mixed-layer LCL
683 m above ground
0-6 km bulk shear
32 kt
0-1 km storm-relative helicity
176 m²/s²
0-3 km storm-relative helicity
215 m²/s²
Significant tornado parameter
0.7
Supercell composite
6.1

Open this sounding in Storm Lab

The text

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

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SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Sep 17, 8:14 PM EDTMesoscale DiscussionSPCCherokee, Clay, Graham, Haywood, Henderson, Jackson and 4 more2 hr
Sep 18, 12:23 AM EDTMesoscale DiscussionSPCAlexander, Buncombe, Burke, Cabarrus, Caldwell, Catawba and 14 more97 min
Sep 18, 8:49 AM EDTMesoscale DiscussionSPCAlamance, Anson, Caswell, Chatham, Cumberland, Davidson and 31 more116 min
Sep 18, 9:45 AM EDTTornado WatchSPCAlamance, Anson, Chatham, Cumberland, Davidson, Durham and 25 more8 hr
Sep 18, 10:54 AM EDTTornado WatchSPCBertie, Camden, Caswell, Chowan, Currituck, Gates and 4 more9 hr
Sep 18, 11:19 AM EDTMesoscale DiscussionSPCAlamance, Caswell, Chatham, Cumberland, Durham, Edgecombe and 27 more86 min
Sep 18, 11:35 AM EDTMesoscale DiscussionSPCUnion85 min
Sep 18, 1:00 PM EDTTornado WatchSPCBeaufort, Carteret, Craven, Dare, Duplin, Greene and 9 more5 hr
Sep 18, 1:21 PM EDTMesoscale DiscussionSPCAlamance, Anson, Chatham, Cumberland, Davidson, Durham and 25 more84 min
Sep 18, 1:27 PM EDTMesoscale DiscussionSPCCamden, Chowan, Currituck, Gates, Hertford, Northampton and 2 more63 min
Sep 18, 3:52 PM EDTMesoscale DiscussionSPCBertie, Camden, Chowan, Gates, Hertford, Northampton and 2 more113 min
Sep 18, 6:15 PM EDTMesoscale DiscussionSPCCamden, Carteret, Chowan, Currituck, Dare, Gates and 5 more30 min

Nearby

Mesoscale Discussions in North Carolina, 2012Every mesoscale discussion 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.