Alert archive / Virginia / Mesoscale Discussions in 2021
Mesoscale Discussion 1060
The Storm Prediction Center issued this mesoscale discussion at Jun 22, 2021, 12:13 PM EDT for 29 counties in North Carolina; 40 counties in Virginia. It was in force for 2 hr.
The area
The outline as issued.
The facts
- Issued
- Jun 22, 2021, 12:13 PM EDT (16:13 UTC)
- Expired
- Jun 22, 2021, 2:15 PM EDT
- In force
- 2 hr
- Issued by
- the Storm Prediction Center
- Concerning
- Severe potential...watch unlikely
- Chance of a watch
- 20%
All 69 counties
Bertie County, NC, Chatham County, NC, Chowan County, NC, Cumberland County, NC, Duplin County, NC, Durham County, NC, Edgecombe County, NC, Franklin County, NC, Gates County, NC, Granville County, NC, Greene County, NC, Halifax County, NC, Harnett County, NC, Hertford County, NC, Johnston County, NC, Jones County, NC, Lee County, NC, Lenoir County, NC, Martin County, NC, Nash County, NC, Northampton County, NC, Perquimans County, NC, Pitt County, NC, Sampson County, NC, Vance County, NC, Wake County, NC, Warren County, NC, Wayne County, NC, Wilson County, NC, Accomack County, VA, Brunswick County, VA, Charles City County, VA, Chesterfield County, VA, City of Chesapeake, VA, City of Colonial Heights, VA, City of Emporia, VA, City of Franklin, VA, City of Hampton, VA, City of Hopewell, VA, City of Newport News, VA, City of Norfolk, VA, City of Petersburg, VA, City of Poquoson, VA, City of Portsmouth, VA, City of Richmond, VA, City of Suffolk, VA, City of Virginia Beach, VA, City of Williamsburg, VA, Dinwiddie County, VA, Essex County, VA, Gloucester County, VA, Greensville County, VA, Henrico County, VA, Isle of Wight County, VA, James City County, VA, King and Queen County, VA, King William County, VA, Lancaster County, VA, Mathews County, VA, Middlesex County, VA, New Kent County, VA, Northampton County, VA, Northumberland County, VA, Prince George County, VA, Richmond County, VA, Southampton County, VA, Surry County, VA, Sussex County, VA, York County, VA
The radar
The Norfolk radar (KAKQ), 53 km from the middle of the area, began a volume at 16:14 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
Roanoke, VA (KRNK), launched 12:00Z, 4.2 hours before the alert went out and 202 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.
- Mixed-layer CAPE
- 98 J/kg
- Mixed-layer CIN
- -27 J/kg
- Mixed-layer LCL
- 631 m above ground
- 0-6 km bulk shear
- 45 kt
- 0-1 km storm-relative helicity
- 21 m²/s²
- 0-3 km storm-relative helicity
- 47 m²/s²
- Significant tornado parameter
- -0.0
- Supercell composite
- -0.2
The text
As transmitted.
273
ACUS11 KWNS 221613
SWOMCD
SPC MCD 221613
VAZ000-MDZ000-NCZ000-221815-
Mesoscale Discussion 1060
NWS Storm Prediction Center Norman OK
1113 AM CDT Tue Jun 22 2021
Areas affected...VA Tidewater...Eastern NC
Concerning...Severe potential...Watch unlikely
Valid 221613Z - 221815Z
Probability of Watch Issuance...20 percent
SUMMARY...Increasing thunderstorm coverage is expected over the next
few hours. A few of these storms may become strong enough to produce
damaging wind gusts.
DISCUSSION...Thunderstorm coverage is gradually expected to increase
over the next few hours from the VA Tidewater southward through much
of the eastern NC. In this region, large-scale forcing for ascent
attendant to the broad upper trough moving across the eastern CONUS
is expected to increase. This forcing for ascent will be augmented
by low-level convergence along a eastward-progressing cold front as
well as confluence within the warm sector. Overall buoyancy has been
tempered by widespread cloud cover, moderated diurnal heating, and
poor mid-level lapse rates. Even so, the moist low-level environment
will still support enough buoyancy for a few strong storms,
especially across the VA Tidewater where vertical shear and buoyancy
are a bit stronger.
A predominantly multicellular storm mode is anticipated, with
relatively fast storm motions (i.e. cloud layer mean wind is around
35 kt) likely resulting in bowing line segments. Downdrafts within a
few of these storms could produce damaging wind gusts. Limited
severe coverage is currently anticipated, but overall convective
trends will be monitored closely.
..Mosier/Hart.. 06/22/2021
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...AKQ...MHX...LWX...RAH...ILM...
LAT...LON 37707742 37997695 38057630 37887574 37477560 36837590
35707668 34677771 34777853 35047926 35537954 36457858
37707742Nearby
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.