Alert archive / Virginia / Mesoscale Discussions in 2017
Mesoscale Discussion 653
The Storm Prediction Center issued this mesoscale discussion at May 5, 2017, 5:56 AM EDT for 18 counties in North Carolina; 30 counties in Virginia. It was in force for 94 min.
The area
The outline as issued.
The facts
- Issued
- May 5, 2017, 5:56 AM EDT (09:56 UTC)
- Expired
- May 5, 2017, 7:30 AM EDT
- In force
- 94 min
- Issued by
- the Storm Prediction Center
All 48 counties
Beaufort County, NC, Bertie County, NC, Camden County, NC, Chowan County, NC, Currituck County, NC, Dare County, NC, Edgecombe County, NC, Gates County, NC, Halifax County, NC, Hertford County, NC, Hyde County, NC, Martin County, NC, Northampton County, NC, Pasquotank County, NC, Perquimans County, NC, Pitt County, NC, Tyrrell County, NC, Washington County, NC, Charles City 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 Suffolk, VA, City of Virginia Beach, VA, City of Williamsburg, VA, Dinwiddie County, VA, Gloucester County, VA, Greensville County, VA, Henrico County, VA, Isle of Wight County, VA, James City County, VA, Mathews County, VA, Middlesex County, VA, New Kent County, VA, Northampton County, VA, Prince George County, VA, Southampton County, VA, Surry County, VA, Sussex County, VA, York County, VA
The radar
The Norfolk radar (KAKQ), 51 km from the middle of the area, began a volume at 09:59 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.
The nearest sounding before it
Wallops Is Stn, VA (KWAL), launched 00:00Z, 9.9 hours before the alert went out and 191 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
- 0 J/kg
- Mixed-layer CIN
- No buoyant parcel
- Mixed-layer LCL
- 876 m above ground
- 0-6 km bulk shear
- 57 kt
- 0-1 km storm-relative helicity
- 219 m²/s²
- 0-3 km storm-relative helicity
- 359 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
267
ACUS11 KWNS 050957
SWOMCD
SPC MCD 050956
NCZ000-VAZ000-051130-
Mesoscale Discussion 0653
NWS Storm Prediction Center Norman OK
0456 AM CDT Fri May 05 2017
Areas affected...Parts of eastern North Carolina and southeastern
Virginia
Concerning...Tornado Watch 195...
Valid 050956Z - 051130Z
The severe weather threat for Tornado Watch 195 continues.
SUMMARY...Some severe weather potential will continue through the
next couple of hours with convection spreading into the coastal
plain of eastern North Carolina and Virginia, and could increase
further after daybreak near coastal areas of southeast Virginia and
northeastern North Carolina. An additional watch is possible within
the next hour or so.
DISCUSSION...A band of convection continues to develop northeastward
at 30-35 kts, across the piedmont toward the coastal plain of
southeastern Virginia and eastern North Carolina. The surface warm
front appears to have advanced north of north central and
northeastern North Carolina, through much of southeastern Virginia.
However, even in the warm sector, a relatively warm mid/upper
environment with weak lapse rates is limiting CAPE and the strength
of the convection. This is evident in the rather low lightning
flash rates associated with the ongoing convection, and virtually no
recent lightning evident to the north of the Virginia/North Carolina
state border. Furthermore, ASOS observations where convection has
passed suggest any wind gusts approaching or exceeding severe
criteria have remain fairly localized.
Still, the combination of heavy rain and gusty winds has been
sufficient to down trees and cause sporadic damage, which may
continue into coastal areas by mid to late morning. Convection
appears generally coincident with a 50 kt southerly 850 mb jet,
which is contributing to strong vertical shear for any boundary
layer based storm development. And the Rapid Refresh has been
suggesting that potential for vigorous boundary layer based storm
development could increase through the 12-15Z time frame, roughly
from the Elizabeth City NC area through the Hampton Roads area.
..Kerr.. 05/05/2017
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...AKQ...MHX...RAH...
LAT...LON 37317761 37727687 37357574 36367557 35537577 35177688
35887788 37317761SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| May 4, 8:49 PM EDT | Tornado Watch | SPC | Bladen, Brunswick, Carteret, Columbus, Craven, Cumberland and 13 more | 6 hr |
| May 4, 11:24 PM EDT | Mesoscale Discussion | SPC | Bladen, Brunswick, Columbus, Duplin, Greene, Jones and 7 more | 66 min |
| May 5, 2:28 AM EDT | Mesoscale Discussion | SPC | Alamance, Beaufort, Bertie, Bladen, Camden, Caswell and 43 more | 92 min |
| May 5, 3:09 AM EDT | Tornado Watch | SPC | Alamance, Anson, Bladen, Brunswick, Carteret, Chatham and 37 more | 6 hr |
| May 5, 6:25 AM EDT | Tornado Watch | SPC | Beaufort, Bertie, Camden, Chowan, Currituck, Dare and 9 more | 5 hr |
| May 5, 8:27 AM EDT | Mesoscale Discussion | SPC | Beaufort, Bertie, Camden, Carteret, Chowan, Craven and 9 more | 93 min |
| May 5, 6:15 PM EDT | Mesoscale Discussion | SPC | Halifax, Hertford, Northampton | 90 min |
Nearby
Mesoscale Discussions in Virginia, 2017Mesoscale Discussions in North Carolina, 2017Every mesoscale discussion in 2017
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.