Alert archive / North Carolina / Mesoscale Discussions in 2021

Mesoscale Discussion 1375

July 28, 202129 counties in North Carolina; City of Franklin, Virginia

The Storm Prediction Center issued this mesoscale discussion at Jul 28, 2021, 4:16 PM EDT for 29 counties in North Carolina; City of Franklin, Virginia. It was in force for 119 min.

The area

The outline as issued.

The facts

Issued
Jul 28, 2021, 4:16 PM EDT (20:16 UTC)
Expired
Jul 28, 2021, 6:15 PM EDT
In force
119 min
Issued by
the Storm Prediction Center
Concerning
Severe thunderstorm watch 398
All 30 counties

Beaufort County, NC, Bertie County, NC, Camden County, NC, Chowan County, NC, Craven County, NC, Cumberland County, NC, Duplin County, NC, Edgecombe County, NC, Gates County, NC, Greene County, NC, Halifax County, NC, Harnett County, NC, Hertford County, NC, Hoke County, NC, Johnston County, NC, Jones County, NC, Lenoir County, NC, Martin County, NC, Nash County, NC, Northampton County, NC, Pasquotank County, NC, Perquimans County, NC, Pitt County, NC, Sampson County, NC, Tyrrell County, NC, Wake County, NC, Washington County, NC, Wayne County, NC, Wilson County, NC, City of Franklin, VA

The radar

The Raleigh/Durham radar (KRAX), 62 km from the middle of the area, began a volume at 20:16 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, 8.3 hours before the alert went out and 124 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 2021-07-28Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 2446 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, Newport, NC at 12:00Z on 2021-07-28The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 61 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
2446 J/kg
Mixed-layer CIN
-4 J/kg
Mixed-layer LCL
613 m above ground
0-6 km bulk shear
21 kt
0-1 km storm-relative helicity
61 m²/s²
0-3 km storm-relative helicity
44 m²/s²
Significant tornado parameter
0.0
Supercell composite
1.0

Open this sounding in Storm Lab

The text

As transmitted.

191 
ACUS11 KWNS 282016
SWOMCD
SPC MCD 282016 
NCZ000-VAZ000-282215-

Mesoscale Discussion 1375
NWS Storm Prediction Center Norman OK
0316 PM CDT Wed Jul 28 2021

Areas affected...Southeastern Virginia and eastern North Carolina

Concerning...Severe Thunderstorm Watch 398...

Valid 282016Z - 282215Z

The severe weather threat for Severe Thunderstorm Watch 398
continues.

SUMMARY...Wind gusts potential will continue within WW 398 as a
cluster of storms in northeast North Carolina moves southwest. The
greatest threat will likely be where cold pool interactions with the
sea breeze and storms moving out of the Piedmont occur.

DISCUSSION...The most prominent cluster of convection has recently
moved out of southeastern Virginia into northeastern North Carolina.
The most intense portion of this cluster has generally been on the
southeastern flank where its outflow has interacted with the sea
breeze front within the Coast Plain. To the west, convection
continues to increase within the surface trough in the Piedmont. As
the primary cluster moves southwestward into the greatest buoyancy
(2500 J/kg MLCAPE) along with slow progression of storms
southeastward away from the Piedmont may lead to additional cold
pool mergers and a subsequent threat for damaging wind gusts.

..Wendt.. 07/28/2021

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

ATTN...WFO...AKQ...MHX...RAH...ILM...

LAT...LON   35467909 36447781 36717706 36547619 36157571 35337625
            34767772 34787846 34857917 35097929 35467909

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jul 28, 12:36 PM EDTMesoscale DiscussionSPCBeaufort, Bertie, Bladen, Camden, Chowan, Craven and 28 more114 min
Jul 28, 2:19 PM EDTSevere Thunderstorm WatchSPCBeaufort, Bertie, Camden, Carteret, Chowan, Craven and 29 more6 hr
Jul 28, 6:07 PM EDTMesoscale DiscussionSPCAnson, Bladen, Brunswick, Columbus, Cumberland, Duplin and 8 more83 min

Nearby

Mesoscale Discussions in North Carolina, 2021Mesoscale Discussions in Virginia, 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.