Alert archive / Virginia / Mesoscale Discussions in 2021

Mesoscale Discussion 1201

July 8, 20218 counties in North Carolina; 17 counties in Virginia

The Storm Prediction Center issued this mesoscale discussion at Jul 8, 2021, 4:08 PM EDT for 8 counties in North Carolina; 17 counties in Virginia. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued
Jul 8, 2021, 4:08 PM EDT (20:08 UTC)
Expired
Jul 8, 2021, 6:15 PM EDT
In force
2 hr
Issued by
the Storm Prediction Center
Concerning
Tornado watch 350
All 25 counties

Camden County, NC, Chowan County, NC, Currituck County, NC, Gates County, NC, Hertford County, NC, Pasquotank County, NC, Perquimans County, NC, Tyrrell County, NC, City of Chesapeake, VA, City of Franklin, VA, City of Hampton, VA, City of Newport News, VA, City of Norfolk, VA, City of Poquoson, VA, City of Portsmouth, VA, City of Suffolk, VA, City of Virginia Beach, VA, City of Williamsburg, VA, Isle of Wight County, VA, James City County, VA, Prince George County, VA, Southampton County, VA, Surry County, VA, Sussex County, VA, York County, VA

The radar

The Norfolk radar (KAKQ), 79 km from the middle of the area, began a volume at 20:09 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

Wallops Is Stn, VA (KWAL), launched 12:00Z, 8.1 hours before the alert went out and 187 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, Wallops Is Stn, VA at 12:00Z on 2021-07-08Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 654 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, Wallops Is Stn, VA at 12:00Z on 2021-07-08The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 29 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
654 J/kg
Mixed-layer CIN
-102 J/kg
Mixed-layer LCL
1222 m above ground
0-6 km bulk shear
20 kt
0-1 km storm-relative helicity
29 m²/s²
0-3 km storm-relative helicity
37 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.3

Open this sounding in Storm Lab

The text

As transmitted.

026 
ACUS11 KWNS 082009
SWOMCD
SPC MCD 082008 
NCZ000-VAZ000-082215-

Mesoscale Discussion 1201
NWS Storm Prediction Center Norman OK
0308 PM CDT Thu Jul 08 2021

Areas affected...northeast North Carolina into southeast Virginia

Concerning...Tornado Watch 350...

Valid 082008Z - 082215Z

The severe weather threat for Tornado Watch 350 continues.

SUMMARY...A tornado threat continues over northeast North Carolina,
and into southeast Virginia shortly.

DISCUSSION...Surface analysis shows a theta-e axis over eastern NC,
with backed easterly surface winds and slightly cooler temperatures
into VA. SRH continues to increase ahead of Elsa, with 0-1 km values
in excess of 200 m2/s2. While the air mass over VA is a bit cooler
than farther south, warm advection into this region may allow the
favorable tornado zone to translate slowly northeastward over the
next few hours.

..Jewell.. 07/08/2021

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

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

LAT...LON   36077562 35757565 35677596 35757617 36067664 36287718
            36557751 36797739 37277721 37377673 37317635 37077606
            36337566 36077562

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jul 8, 1:38 AM EDTMesoscale DiscussionSPCBladen, Brunswick, Columbus, New Hanover, Pender, Robeson2 hr
Jul 8, 2:01 AM EDTTornado WatchSPCBladen, Brunswick, Columbus, New Hanover, Pender7 hr
Jul 8, 7:09 AM EDTMesoscale DiscussionSPCBladen, Brunswick, Carteret, Columbus, Craven, Duplin and 11 more2 hr
Jul 8, 8:35 AM EDTTornado WatchSPCBeaufort, Bladen, Brunswick, Carteret, Columbus, Craven and 23 more6 hr
Jul 8, 12:11 PM EDTMesoscale DiscussionSPCBeaufort, Bertie, Camden, Carteret, Chowan, Craven and 23 more2 hr
Jul 8, 1:50 PM EDTTornado WatchSPCBeaufort, Bertie, Camden, Chowan, Currituck, Dare and 11 more11 hr
Jul 8, 6:48 PM EDTMesoscale DiscussionSPCBeaufort, Bertie, Camden, Chowan, Currituck, Dare and 8 more117 min

Nearby

Mesoscale Discussions in Virginia, 2021Mesoscale Discussions in North 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.