Alert archive / South Carolina / Mesoscale Discussions in 2021

Mesoscale Discussion 1194

July 8, 20217 counties in South Carolina

The Storm Prediction Center issued this mesoscale discussion at Jul 8, 2021, 5:25 AM EDT for 7 counties in South Carolina. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued
Jul 8, 2021, 5:25 AM EDT (09:25 UTC)
Expired
Jul 8, 2021, 7:30 AM EDT
In force
2 hr
Issued by
the Storm Prediction Center
Concerning
Tornado watch 348

Counties Berkeley County, SC, Dillon County, SC, Florence County, SC, Georgetown County, SC, Horry County, SC, Marion County, SC, Williamsburg County, SC

The radar

The Wilmington radar (KLTX), 110 km from the middle of the area, began a volume at 09:28 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, 9.4 hours before the alert went out and 83 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 2021-07-08Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1185 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 2021-07-08The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 41 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
1185 J/kg
Mixed-layer CIN
-3 J/kg
Mixed-layer LCL
801 m above ground
0-6 km bulk shear
6 kt
0-1 km storm-relative helicity
41 m²/s²
0-3 km storm-relative helicity
63 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

065 
ACUS11 KWNS 080926
SWOMCD
SPC MCD 080925 
NCZ000-SCZ000-081130-

Mesoscale Discussion 1194
NWS Storm Prediction Center Norman OK
0425 AM CDT Thu Jul 08 2021

Areas affected...east-central and northeastern South Carolina/far
southeastern North Carolina

Concerning...Tornado Watch 348...

Valid 080925Z - 081130Z

The severe weather threat for Tornado Watch 348 continues.

SUMMARY...Risk for brief tornadoes continues to the east and
northeast of the center of Tropical Storm Elsa.

DISCUSSION...Latest radar loops shows a couple of stronger
convective bands east and northeast of Elsa's center.  Cells in and
near the more eastern of these convective bands -- stretching inland
across Georgetown County and northwestward across Florence County
South Carolina at this time -- continue to be those exhibiting most
of the indicated low-level rotation that has been observed by
WSR-88D storm-relative velocity data over the past couple of hours.

As Elsa -- and the associated convective bands -- continue shifting
steadily north/northeastward, risk for brief tornadoes will
gradually impinge on some of the southeastern-most counties in North
Carolina, over the next couple of hours.

..Goss.. 07/08/2021

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

ATTN...WFO...ILM...CHS...CAE...

LAT...LON   32787969 33208003 33598012 33948020 34287987 34557916
            34047850 33087847 32677880 32787969

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jul 7, 10:00 PM EDTMesoscale DiscussionSPCBeaufort, Hampton, Jasper2 hr
Jul 8, 1:38 AM EDTMesoscale DiscussionSPCBeaufort, Berkeley, Charleston, Colleton, Dillon, Dorchester and 5 more2 hr
Jul 8, 2:01 AM EDTTornado WatchSPCFlorence, Georgetown, Horry, Marion, Williamsburg7 hr
Jul 8, 7:09 AM EDTMesoscale DiscussionSPCGeorgetown, Horry, Marion2 hr

Nearby

Mesoscale Discussions in South Carolina, 2021Every mesoscale discussion in 2021

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.