Alert archive / North Carolina / Mesoscale Discussions in 2015

Mesoscale Discussion 396

April 20, 201513 counties in Georgia; 26 counties in North Carolina; 19 counties in South Carolina

The Storm Prediction Center issued this mesoscale discussion at Apr 20, 2015, 1:03 PM EDT for 13 counties in Georgia; 26 counties in North Carolina; 19 counties in South Carolina. It was in force for 57 min.

The area

The outline as issued.

The facts

Issued
Apr 20, 2015, 1:03 PM EDT (17:03 UTC)
Expired
Apr 20, 2015, 2:00 PM EDT
In force
57 min
Issued by
the Storm Prediction Center
Chance of a watch
95%
All 58 counties

Banks County, GA, Clarke County, GA, Elbert County, GA, Franklin County, GA, Habersham County, GA, Hall County, GA, Hart County, GA, Jackson County, GA, Madison County, GA, Oglethorpe County, GA, Rabun County, GA, Stephens County, GA, White County, GA, Alexander County, NC, Anson County, NC, Buncombe County, NC, Burke County, NC, Cabarrus County, NC, Caldwell County, NC, Catawba County, NC, Cleveland County, NC, Davidson County, NC, Davie County, NC, Gaston County, NC, Henderson County, NC, Iredell County, NC, Jackson County, NC, Lincoln County, NC, McDowell County, NC, Mecklenburg County, NC, Montgomery County, NC, Moore County, NC, Polk County, NC, Richmond County, NC, Rowan County, NC, Rutherford County, NC, Stanly County, NC, Transylvania County, NC, Union County, NC, Abbeville County, SC, Anderson County, SC, Cherokee County, SC, Chester County, SC, Chesterfield County, SC, Fairfield County, SC, Greenville County, SC, Greenwood County, SC, Kershaw County, SC, Lancaster County, SC, Laurens County, SC, McCormick County, SC, Newberry County, SC, Oconee County, SC, Pickens County, SC, Saluda County, SC, Spartanburg County, SC, Union County, SC, York County, SC

The radar

The Greer radar (KGSP), 49 km from the middle of the area, began a volume at 17:03 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 watches that followed

Watches SPC issued over any of the same counties within four hours of this discussion.

The nearest sounding before it

Greensboro/Hi Pt, NC (KGSO), launched 12:00Z, 5.1 hours before the alert went out and 221 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, Greensboro/Hi Pt, NC at 12:00Z on 2015-04-20Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 17 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, Greensboro/Hi Pt, NC at 12:00Z on 2015-04-20The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 59 square meters per square second.19395878Sfc1 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
17 J/kg
Mixed-layer CIN
-48 J/kg
Mixed-layer LCL
654 m above ground
0-6 km bulk shear
39 kt
0-1 km storm-relative helicity
59 m²/s²
0-3 km storm-relative helicity
77 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.4

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
Apr 20, 2:09 AM EDTSevere Thunderstorm WatchSPCCatoosa, Chattooga, Dade, Floyd, Gordon, Walker and 1 more4 hr
Apr 20, 3:36 AM EDTMesoscale DiscussionSPCCatoosa, Chattooga, Dade, Floyd, Gordon, Murray and 2 more84 min
Apr 20, 11:04 AM EDTSevere Thunderstorm WatchSPCAppling, Atkinson, Bacon, Baker, Ben Hill, Berrien and 25 more8 hr
Apr 20, 1:23 PM EDTTornado WatchSPCBanks, Barrow, Clarke, Clayton, Cobb, Coweta and 22 more7 hr
Apr 20, 4:18 PM EDTMesoscale DiscussionSPCBanks, Barrow, Clarke, Elbert, Franklin, Habersham and 9 more57 min
Apr 20, 4:36 PM EDTTornado WatchSPCLincoln5 hr
Apr 20, 6:45 PM EDTMesoscale DiscussionSPCBanks, Barrow, Clarke, DeKalb, Elbert, Forsyth and 17 more60 min
Apr 19, 9:06 PM EDTMesoscale DiscussionSPCBladen, Brunswick, Duplin, Durham, Edgecombe, Franklin and 13 more54 min
Apr 20, 2:25 AM EDTMesoscale DiscussionSPCBeaufort, Bertie, Camden, Chowan, Craven, Currituck and 16 more95 min
Apr 20, 1:54 PM EDTMesoscale DiscussionSPCAlleghany, Stokes, Surry3 hr
Apr 20, 2:55 PM EDTSevere Thunderstorm WatchSPCAlamance, Alleghany, Anson, Ashe, Bertie, Caswell and 33 more7 hr
Apr 20, 6:27 PM EDTMesoscale DiscussionSPCAlamance, Alleghany, Caswell, Chatham, Durham, Forsyth and 16 more93 min

Nearby

Mesoscale Discussions in North Carolina, 2015Mesoscale Discussions in South Carolina, 2015Mesoscale Discussions in Georgia, 2015Every mesoscale discussion in 2015

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.