Alert archive / Virginia / Mesoscale Discussions in 2017
Mesoscale Discussion 243
The Storm Prediction Center issued this mesoscale discussion at Mar 1, 2017, 12:50 PM EST for 6 states. It was in force for 55 min.
The area
The outline as issued.
The facts
- Issued
- Mar 1, 2017, 12:50 PM EST (17:50 UTC)
- Expired
- Mar 1, 2017, 1:45 PM EST
- In force
- 55 min
- Issued by
- the Storm Prediction Center
- Chance of a watch
- 80%
All 81 counties
Kent County, DE, New Castle County, DE, Sussex County, DE, Caroline County, MD, Dorchester County, MD, Saint Mary's County, MD, Somerset County, MD, Wicomico County, MD, Worcester County, MD, Gates County, NC, Granville County, NC, Halifax County, NC, Hertford County, NC, Northampton County, NC, Vance County, NC, Warren County, NC, Atlantic County, NJ, Burlington County, NJ, Camden County, NJ, Cape May County, NJ, Cumberland County, NJ, Gloucester County, NJ, Hunterdon County, NJ, Mercer County, NJ, Middlesex County, NJ, Monmouth County, NJ, Ocean County, NJ, Salem County, NJ, Somerset County, NJ, Bucks County, PA, Chester County, PA, Delaware County, PA, Montgomery County, PA, Philadelphia County, PA, Accomack County, VA, Amelia 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, Hanover 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, Lunenburg County, VA, Mathews County, VA, Mecklenburg County, VA, Middlesex County, VA, New Kent County, VA, Northampton County, VA, Northumberland County, VA, Nottoway County, VA, Powhatan County, VA, Prince George County, VA, Richmond County, VA, Southampton County, VA, Surry County, VA, Sussex County, VA, Westmoreland County, VA, York County, VA
The radar
The Dover AFB radar (KDOX), 54 km from the middle of the area, began a volume at 17:49 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 12:00Z, 5.8 hours before the alert went out and 79 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
- 127 J/kg
- Mixed-layer CIN
- -119 J/kg
- Mixed-layer LCL
- 840 m above ground
- 0-6 km bulk shear
- 60 kt
- 0-1 km storm-relative helicity
- 287 m²/s²
- 0-3 km storm-relative helicity
- 274 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.6
The text
As transmitted.
914
ACUS11 KWNS 011750
SWOMCD
SPC MCD 011750
NJZ000-NYZ000-PAZ000-MDZ000-DEZ000-VAZ000-NCZ000-011845-
Mesoscale Discussion 0243
NWS Storm Prediction Center Norman OK
1150 AM CST Wed Mar 01 2017
Areas affected...Northern NC...eastern VA...the Delmarva
Peninsula...NJ...and southeastern PA
Concerning...Severe potential...Watch likely
Valid 011750Z - 011845Z
Probability of Watch Issuance...80 percent
SUMMARY...A damaging wind and isolated tornado threat will increase
with a line of storms approaching from the west. Watch issuance is
likely.
DISCUSSION...An ongoing line of showers and thunderstorms across
central/western VA is quickly advancing eastward. As it does so,
this line should strengthen as it encounters an increasingly moist
and unstable airmass. Diurnal heating has allowed temperatures to
warm into the upper 60s to upper 70s as of 1745Z, with surface
dewpoints generally in the mid 50s to lower 60s. The instability
should build northward with time across NJ. 15Z sounding from GSO
and 16Z sounding from RNK both reveal steep mid-level lapse rates
around 8 degrees C/km that will support weak to moderate instability
across this area through the afternoon. Widespread damaging winds
appear likely as the convective line restrengthens. In addition, RAP
forecast soundings show enlarged low-level hodographs across the
eastern VA into Delmarva Peninsula and southern/central NJ, as winds
veer from generally southerly to southwesterly with height while
also strengthening. This should support an isolated tornado threat
with embedded circulations within the line.
..Gleason/Hart.. 03/01/2017
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...OKX...PHI...AKQ...LWX...RAH...
LAT...LON 38447628 39527590 40417576 40757495 40457382 39757398
38707477 37517542 36567604 36097735 36237870 37857774
38447628SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Mar 1, 1:13 PM EST | Severe Thunderstorm Watch | SPC | Kent, New Castle, Sussex | 4 hr |
| Mar 1, 2:50 PM EST | Mesoscale Discussion | SPC | Kent, New Castle, Sussex | 55 min |
| Mar 1, 9:44 AM EST | Mesoscale Discussion | SPC | Allegany, Baltimore, Carroll, Charles, Frederick, Garrett and 6 more | 91 min |
| Mar 1, 10:38 AM EST | Severe Thunderstorm Watch | SPC | Allegany, Anne Arundel, Baltimore, Calvert, Carroll, Charles and 8 more | 4 hr |
| Mar 1, 12:25 PM EST | Mesoscale Discussion | SPC | Baltimore, Carroll, Frederick, Howard, Montgomery, Washington and 1 more | 65 min |
| Mar 1, 12:48 PM EST | Tornado Watch | SPC | Cherokee, Clay | 6 hr |
| Mar 1, 2:07 PM EST | Mesoscale Discussion | SPC | Alexander, Buncombe, Burke, Cabarrus, Catawba, Cleveland and 16 more | 113 min |
| Mar 1, 3:02 PM EST | Severe Thunderstorm Watch | SPC | Alamance, Alexander, Anson, Avery, Buncombe, Burke and 43 more | 7 hr |
| Mar 1, 6:21 PM EST | Mesoscale Discussion | SPC | Alamance, Anson, Beaufort, Bertie, Bladen, Cabarrus and 40 more | 114 min |
| Mar 1, 2:19 AM EST | Mesoscale Discussion | SPC | Allegheny, Armstrong, Beaver, Butler, Cambria, Clarion and 13 more | 86 min |
| Mar 1, 3:56 PM EST | Mesoscale Discussion | SPC | Beaver, Butler, Crawford, Lawrence, Mercer, Venango and 1 more | 2 hr |
| Mar 1, 6:28 AM EST | Mesoscale Discussion | SPC | Dickenson, Lee, Wise | 2 hr |
| Mar 1, 7:47 AM EST | Severe Thunderstorm Watch | SPC | Buchanan, Dickenson, Lee, Russell, Scott, Washington and 3 more | 5 hr |
| Mar 1, 8:28 AM EST | Mesoscale Discussion | SPC | Buchanan, Dickenson, Lee, Russell, Scott, Tazewell and 2 more | 92 min |
Nearby
Mesoscale Discussions in Virginia, 2017Mesoscale Discussions in New Jersey, 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.