Alert archive / North Carolina / Mesoscale Discussions in 2021

Mesoscale Discussion 580

May 10, 202152 counties in North Carolina; City of Chesapeake, City of Franklin, City of Suffolk, Virginia

The Storm Prediction Center issued this mesoscale discussion at May 10, 2021, 12:51 PM EDT for 52 counties in North Carolina; City of Chesapeake, City of Franklin, City of Suffolk, Virginia. It was in force for 114 min.

The area

The outline as issued.

The facts

Issued: May 10, 2021, 12:51 PM EDT (16:51 UTC)
Expired: May 10, 2021, 2:45 PM EDT
In force: 114 min
Issued by: the Storm Prediction Center
Concerning: Severe potential...watch possible
Chance of a watch: 40%

All 55 counties

Alamance County, NC, Beaufort County, NC, Bertie County, NC, Bladen County, NC, Camden County, NC, Carteret County, NC, Caswell County, NC, Chatham County, NC, Chowan County, NC, Craven County, NC, Cumberland County, NC, Currituck County, NC, Dare County, NC, Duplin County, NC, Durham County, NC, Edgecombe County, NC, Franklin County, NC, Gates County, NC, Granville County, NC, Greene County, NC, Guilford County, NC, Halifax County, NC, Harnett County, NC, Hertford County, NC, Hoke County, NC, Hyde County, NC, Johnston County, NC, Jones County, NC, Lee County, NC, Lenoir County, NC, Martin County, NC, Moore County, NC, Nash County, NC, New Hanover County, NC, Northampton County, NC, Onslow County, NC, Orange County, NC, Pamlico County, NC, Pasquotank County, NC, Pender County, NC, Perquimans County, NC, Person County, NC, Pitt County, NC, Randolph County, NC, Sampson County, NC, Tyrrell County, NC, Vance County, NC, Wake County, NC, Warren County, NC, Washington County, NC, Wayne County, NC, Wilson County, NC, City of Chesapeake, VA, City of Franklin, VA, City of Suffolk, VA

The radar

The Morehead City radar (KMHX), 84 km from the middle of the area, began a volume at 16:50 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 watches that followed

Watches SPC issued over any of the same counties within four hours of this discussion.

Severe Thunderstorm Watch 163May 10, 4:00 PM EDT

The nearest sounding before it

Newport, NC (KMHX), launched 12:00Z, 4.9 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-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: 1414 J/kg
Mixed-layer CIN: -27 J/kg
Mixed-layer LCL: 607 m above ground
0-6 km bulk shear: 45 kt
0-1 km storm-relative helicity: 235 m²/s²
0-3 km storm-relative helicity: 235 m²/s²
Significant tornado parameter: 1.6
Supercell composite: 7.9

Open this sounding in Storm Lab

The text

As transmitted.

331 
ACUS11 KWNS 101651
SWOMCD
SPC MCD 101651 
NCZ000-VAZ000-101845-

Mesoscale Discussion 0580
NWS Storm Prediction Center Norman OK
1151 AM CDT Mon May 10 2021

Areas affected...Eastern North Carolina

Concerning...Severe potential...Watch possible 

Valid 101651Z - 101845Z

Probability of Watch Issuance...40 percent

SUMMARY...Thunderstorm development may continue well into the
afternoon hours across eastern North Carolina as temperatures
continue to warm. A few strong to severe storms are possible and may
pose a hail/wind risk.

DISCUSSION...A couple of thunderstorms have developed over the past
30 minutes in the pre-frontal environment across eastern NC where
surface temperatures are warming into the upper 70s and low 80s.
These temperatures are approaching low-level parcel convective
temperatures per the 12 UTC MHX sounding, which also exhibited weak
MLCIN and nearly 1500 J/kg MLCAPE. A weak mid-level impulse
propagating across the Mid-Atlantic region (noted in region VWP obs
and low-level water-vapor imagery) may also be aiding in regional
ascent. GOES visible imagery shows growing cumulus across eastern
NC, suggesting that additional thunderstorm development is possible
in the next 1-2 hours. The Mid-Atlantic is on the periphery of the
stronger upper-level jet streak to the north, which is supporting
35-45 knots of effective bulk shear over the region. Organized
storms will likely pose a hail and wind threat, especially across
east-central and southeast NC where low-level lapse rates are
steepening to near 8 C/km. It is unclear how long this threat will
last before storms move offshore, but additional convection is
possible later this afternoon as the cold front progresses eastward
through the state. Trends will continue to be monitored, and a watch
is possible.

..Moore/Thompson.. 05/10/2021

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

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

LAT...LON   34037783 34317853 34927930 35507997 36047986 36427949
            36567865 36747634 36617552 36127538 35427533 35007563
            34717627 34447673 34487722 34037783

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
May 10, 3:57 PM EDT	Severe Thunderstorm Watch	SPC	Alamance, Beaufort, Chatham, Craven, Cumberland, Davidson and 25 more	6 hr
May 10, 6:07 PM EDT	Mesoscale Discussion	SPC	Edgecombe, Franklin, Greene, Johnston, Lenoir, Martin and 5 more	53 min

Nearby

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