Alert archive / North Carolina / Mesoscale Discussions in 2021

Mesoscale Discussion 1216

July 9, 202120 counties in North Carolina; 5 counties in South Carolina

The Storm Prediction Center issued this mesoscale discussion at Jul 9, 2021, 5:40 PM EDT for 20 counties in North Carolina; 5 counties in South Carolina. It was in force for 95 min.

The area

The outline as issued.

The facts

Issued
Jul 9, 2021, 5:40 PM EDT (21:40 UTC)
Expired
Jul 9, 2021, 7:15 PM EDT
In force
95 min
Issued by
the Storm Prediction Center
Concerning
Severe potential...watch unlikely
Chance of a watch
5%
All 25 counties

Beaufort County, NC, Bertie County, NC, Bladen County, NC, Brunswick County, NC, Chowan County, NC, Columbus County, NC, Duplin County, NC, Edgecombe County, NC, Greene County, NC, Jones County, NC, Lenoir County, NC, Martin County, NC, Onslow County, NC, Pender County, NC, Pitt County, NC, Robeson County, NC, Sampson County, NC, Washington County, NC, Wayne County, NC, Wilson County, NC, Berkeley County, SC, Georgetown County, SC, Horry County, SC, Marion County, SC, Williamsburg County, SC

The radar

The Wilmington radar (KLTX), 50 km from the middle of the area, began a volume at 21:41 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, 9.7 hours before the alert went out and 165 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 2021-07-09Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 871 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 2021-07-09The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 41 square meters per square second.1939Sfc1 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
871 J/kg
Mixed-layer CIN
-40 J/kg
Mixed-layer LCL
929 m above ground
0-6 km bulk shear
11 kt
0-1 km storm-relative helicity
41 m²/s²
0-3 km storm-relative helicity
71 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

510 
ACUS11 KWNS 092141
SWOMCD
SPC MCD 092140 
NCZ000-SCZ000-092315-

Mesoscale Discussion 1216
NWS Storm Prediction Center Norman OK
0440 PM CDT Fri Jul 09 2021

Areas affected...Carolina coastal plain

Concerning...Severe potential...Watch unlikely 

Valid 092140Z - 092315Z

Probability of Watch Issuance...5 percent

SUMMARY...Several strong to locally severe thunderstorms (capable of
45-60 mph gusts) are possible through early this evening (8pm EDT). 
The risk for wind damage will likely diminish thereafter.

DISCUSSION...Radar mosaic shows a couple of broken linear clusters
of storms extending from central GA northeastward across the
Carolinas to far southeast VA.  A surface trough was analyzed from
the Savannah River Valley northeast to 20 mi southeast the Research
Triangle.  The airmass ahead of the thunderstorms is considered very
moist and unstable with temperatures around 90 deg in inland areas
away from the beaches, and dewpoints ranging the mid-upper 70s. 
Area 88D VAD data shows flow at or below 20 kt from the west.  Most
of the thunderstorm activity will likely remain tempered in overall
intensity (due to the limited shear) but a few stronger cores could
lead to water-loaded wet microbursts.  The stronger downdrafts will
be capable of wind damage (45-55 mph) but locally up to near 60 mph.

..Smith/Thompson.. 07/09/2021

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

ATTN...WFO...AKQ...MHX...RAH...ILM...CHS...CAE...

LAT...LON   33218055 34187955 35627821 36377671 35857641 34567761
            33817841 32897963 33218055

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jul 9, 2:15 PM EDTMesoscale DiscussionSPCGranville, Northampton, Vance, Warren2 hr

Nearby

Mesoscale Discussions in North Carolina, 2021Mesoscale 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.