Alert archive / North Carolina / Mesoscale Discussions in 2021

Mesoscale Discussion 301

March 28, 202119 counties in North Carolina; 5 counties in Virginia

The Storm Prediction Center issued this mesoscale discussion at Mar 28, 2021, 4:53 PM EDT for 19 counties in North Carolina; 5 counties in Virginia. It was in force for 67 min.

The area

The outline as issued.

The facts

Issued
Mar 28, 2021, 4:53 PM EDT (20:53 UTC)
Expired
Mar 28, 2021, 6:00 PM EDT
In force
67 min
Issued by
the Storm Prediction Center
Concerning
Severe thunderstorm watch 68
All 24 counties

Beaufort County, NC, Bertie County, NC, Camden County, NC, Chowan County, NC, Craven County, NC, Currituck County, NC, Gates County, NC, Greene County, NC, Hertford County, NC, Hyde County, NC, Jones County, NC, Lenoir County, NC, Martin County, NC, Pamlico County, NC, Pasquotank County, NC, Perquimans County, NC, Pitt County, NC, Tyrrell County, NC, Washington County, NC, City of Chesapeake, VA, City of Norfolk, VA, City of Portsmouth, VA, City of Suffolk, VA, City of Virginia Beach, VA

The radar

The Morehead City radar (KMHX), 109 km from the middle of the area, began a volume at 20:55 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, 8.9 hours before the alert went out and 108 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 2021-03-28Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 184 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 2021-03-28The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 171 square meters per square second.1939587897Sfc1 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
184 J/kg
Mixed-layer CIN
-190 J/kg
Mixed-layer LCL
936 m above ground
0-6 km bulk shear
60 kt
0-1 km storm-relative helicity
171 m²/s²
0-3 km storm-relative helicity
79 m²/s²
Significant tornado parameter
0.0
Supercell composite
3.8

Open this sounding in Storm Lab

The text

As transmitted.

881 
ACUS11 KWNS 282054
SWOMCD
SPC MCD 282053 
NCZ000-VAZ000-282200-

Mesoscale Discussion 0301
NWS Storm Prediction Center Norman OK
0353 PM CDT Sun Mar 28 2021

Areas affected...Southeast Virginia and eastern North Carolina

Concerning...Severe Thunderstorm Watch 68...

Valid 282053Z - 282200Z

The severe weather threat for Severe Thunderstorm Watch 68
continues.

SUMMARY...Threat for damaging wind gusts across WW68 should continue
into early evening.

DISCUSSION...A broken band of storms roughly along the I-95 corridor
from Virginia southward will continue to move east over the next few
hours. A few wind gusts to 50kts have been noted with these storms
suggesting a damaging wind risk remains. SPC mesoanalysis indicates
sufficient buoyancy of 1000-1500 J/kg of MLCAPE exists east of the
ongoing storms. This should continue to support strong updraft
development and a subsequent severe weather risk into the early
evening. Storm longevity is a bit more questionable farther east
toward the coast where a modified airmass exists behind an inland
seabreaze front. Cooler temperatures should eventually weaken storms
near the coast and barrier islands this evening.

..Lyons.. 03/28/2021

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

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

LAT...LON   34957702 34977839 35377793 35867746 36257715 36547691
            36997664 37007593 36327566 35737573 35377597 35167633
            35027671 34957702

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Mar 28, 2:25 AM EDTMesoscale DiscussionSPCAvery, Buncombe, Cherokee, Clay, Graham, Haywood and 7 more2 hr
Mar 28, 3:07 AM EDTSevere Thunderstorm WatchSPCCherokee, Clay, Graham, Macon, Swain6 hr
Mar 28, 12:38 PM EDTMesoscale DiscussionSPCAlamance, Anson, Cabarrus, Caswell, Chatham, Cumberland and 19 more3 hr
Mar 28, 3:24 PM EDTSevere Thunderstorm WatchSPCBeaufort, Bertie, Camden, Chowan, Craven, Cumberland and 26 more4 hr
Mar 28, 1:24 PM EDTMesoscale DiscussionSPCAccomack, Amelia, Appomattox, Arlington, Brunswick, Buckingham and 66 more2 hr
Mar 28, 5:05 PM EDTSevere Thunderstorm WatchSPCArlington, Fairfax, Fauquier, Prince William, Stafford, City of Alexandria and 3 more4 hr

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.