Alert archive / North Carolina / Mesoscale Discussions in 2018

Mesoscale Discussion 270

April 15, 20189 counties in North Carolina; 6 counties in South Carolina

The Storm Prediction Center issued this mesoscale discussion at Apr 15, 2018, 3:17 PM EDT for 9 counties in North Carolina; 6 counties in South Carolina. It was in force for 88 min.

The area

The outline as issued.

The facts

Issued: Apr 15, 2018, 3:17 PM EDT (19:17 UTC)
Expired: Apr 15, 2018, 4:45 PM EDT
In force: 88 min
Issued by: the Storm Prediction Center

Counties Anson County, NC, Cabarrus County, NC, Davidson County, NC, Davie County, NC, Forsyth County, NC, Rowan County, NC, Stanly County, NC, Stokes County, NC, Union County, NC, Berkeley County, SC, Chesterfield County, SC, Clarendon County, SC, Dorchester County, SC, Lee County, SC, Sumter County, SC

The radar

The Columbia radar (KCAE), 87 km from the middle of the area, began a volume at 19:18 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

Charleston AFB, SC (KCHS), launched 12:00Z, 7.3 hours before the alert went out and 170 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: 844 J/kg
Mixed-layer CIN: -13 J/kg
Mixed-layer LCL: 587 m above ground
0-6 km bulk shear: 39 kt
0-1 km storm-relative helicity: 148 m²/s²
0-3 km storm-relative helicity: 129 m²/s²
Significant tornado parameter: 0.6
Supercell composite: 4.5

Open this sounding in Storm Lab

The text

As transmitted.

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SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Apr 15, 11:15 AM EDT	Mesoscale Discussion	SPC	Alexander, Anson, Cabarrus, Catawba, Davidson, Davie and 11 more	2 hr
Apr 15, 12:13 PM EDT	Tornado Watch	SPC	Alexander, Alleghany, Ashe, Burke, Cabarrus, Caldwell and 16 more	9 hr
Apr 15, 2:29 PM EDT	Mesoscale Discussion	SPC	Alamance, Anson, Caswell, Chatham, Cumberland, Davidson and 20 more	91 min
Apr 15, 3:02 PM EDT	Tornado Watch	SPC	Alamance, Anson, Bladen, Brunswick, Caswell, Chatham and 34 more	8 hr
Apr 15, 5:45 PM EDT	Mesoscale Discussion	SPC	Alamance, Anson, Cabarrus, Caswell, Chatham, Cumberland and 24 more	90 min
Apr 15, 6:28 PM EDT	Mesoscale Discussion	SPC	Cumberland, Franklin, Granville, Halifax, Johnston, Nash and 4 more	62 min

Nearby

Mesoscale Discussions in North Carolina, 2018 Mesoscale Discussions in South Carolina, 2018 Every mesoscale discussion 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.