Alert archive / South Carolina / Mesoscale Discussions in 2020

Mesoscale Discussion 101

February 6, 2020Brunswick County, Carteret County, New Hanover County, North Carolina; 4 counties in South Carolina

The Storm Prediction Center issued this mesoscale discussion at Feb 6, 2020, 11:32 PM EST for Brunswick County, Carteret County, New Hanover County, North Carolina; 4 counties in South Carolina. It was in force for 118 min.

The area

The outline as issued.

The facts

Issued
Feb 6, 2020, 11:32 PM EST (04:32 UTC)
Expired
Feb 7, 2020, 1:30 AM EST
In force
118 min
Issued by
the Storm Prediction Center

Counties Brunswick County, NC, Carteret County, NC, New Hanover County, NC, Berkeley County, SC, Charleston County, SC, Georgetown County, SC, Horry County, SC

The radar

The Wilmington radar (KLTX), 52 km from the middle of the area, began a volume at 04:32 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 00:00Z, 4.5 hours before the alert went out and 147 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, Charleston AFB, SC at 00:00Z on 2020-02-07Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 251 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, Charleston AFB, SC at 00:00Z on 2020-02-07The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 412 square meters per square second.1939587897117Sfc1 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
251 J/kg
Mixed-layer CIN
-50 J/kg
Mixed-layer LCL
718 m above ground
0-6 km bulk shear
75 kt
0-1 km storm-relative helicity
412 m²/s²
0-3 km storm-relative helicity
427 m²/s²
Significant tornado parameter
0.7
Supercell composite
5.5

Open this sounding in Storm Lab

The text

As transmitted.

523 
ACUS11 KWNS 070433
SWOMCD
SPC MCD 070432 
NCZ000-SCZ000-070630-

Mesoscale Discussion 0101
NWS Storm Prediction Center Norman OK
1032 PM CST Thu Feb 06 2020

Areas affected...the central South Carolina coast into coastal North
Carolina

Concerning...Tornado Watch 31...

Valid 070432Z - 070630Z

The severe weather threat for Tornado Watch 31 continues.

SUMMARY...A small area of the coastal Carolinas may experience
locally strong to severe wind gusts. Tornado threat more
conditional.

DISCUSSION...A severe QLCS that produced wind damage over the JAX
area and southeast GA continues to move rapidly offshore. Recently,
northern portions of this line have shown organization into coastal
SC, though low-level velocities have not indicated severe over land.

Downstream of this system, an outflow boundary has pushed south
along the NC coast, and now through MYR SC. Pressure falls continue
across this region due to very strong south winds off the surface.
Should the boundary reverse northward over the next few hours, there
could be a narrow ribbon of land with severe wind potential. Surface
obs will be monitored closely for any indication of a returning
front. Shear will remain exceptionally strong, with little
surface-based instability required for a localized severe threat.

..Jewell/Grams.. 02/07/2020

...Please see www.spc.noaa.gov for graphic product...

ATTN...WFO...MHX...ILM...CHS...

LAT...LON   32528007 32438034 32948029 33398021 33827922 34317811
            34807704 34907645 34687618 34337638 33927741 33677813
            33127899 32857940 32657975 32528007

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Feb 6, 8:09 PM ESTMesoscale DiscussionSPCBeaufort, Bladen, Brunswick, Carteret, Columbus, Craven and 11 more96 min
Feb 6, 7:32 PM ESTMesoscale DiscussionSPCBeaufort, Charleston, Colleton, Dorchester, Hampton, Jasper118 min

Nearby

Mesoscale Discussions in South Carolina, 2020Mesoscale Discussions in North Carolina, 2020Every mesoscale discussion in 2020

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.