Alert archive / Virginia / Mesoscale Discussions in 2004
Mesoscale Discussion 2149
The Storm Prediction Center issued this mesoscale discussion at Aug 30, 2004, 12:07 PM EDT for Saint Mary's County, Maryland; 9 counties in North Carolina; 55 counties in Virginia. It was in force for 113 min.
The area
The outline as issued.
The facts
- Issued
- Aug 30, 2004, 12:07 PM EDT (16:07 UTC)
- Expired
- Aug 30, 2004, 2:00 PM EDT
- In force
- 113 min
- Issued by
- the Storm Prediction Center
All 65 counties
Saint Mary's County, MD, Camden County, NC, Chowan County, NC, Currituck County, NC, Gates County, NC, Hertford County, NC, Pasquotank County, NC, Perquimans County, NC, Tyrrell County, NC, Washington County, NC, Amelia County, VA, Brunswick County, VA, Caroline 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 Fredericksburg, 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, Cumberland County, VA, Dinwiddie County, VA, Essex County, VA, Fluvanna County, VA, Gloucester County, VA, Goochland 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 George County, VA, King William County, VA, Lancaster County, VA, Louisa County, VA, Lunenburg County, VA, Mathews County, VA, Middlesex County, VA, New Kent County, VA, Northampton County, VA, Northumberland County, VA, Nottoway County, VA, Powhatan County, VA, Prince Edward County, VA, Prince George County, VA, Richmond County, VA, Southampton County, VA, Spotsylvania County, VA, Stafford County, VA, Surry County, VA, Sussex County, VA, Westmoreland County, VA, York County, VA
The radar
The Norfolk radar (KAKQ), 24 km from the middle of the area, began a volume at 16:10 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, 4.1 hours before the alert went out and 192 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
- 2008 J/kg
- Mixed-layer CIN
- 0 J/kg
- Mixed-layer LCL
- 468 m above ground
- 0-6 km bulk shear
- 25 kt
- 0-1 km storm-relative helicity
- 45 m²/s²
- 0-3 km storm-relative helicity
- 61 m²/s²
- Significant tornado parameter
- 0.4
- Supercell composite
- 2.5
The text
As transmitted, in the capitals the NWS used until 2016.
919 ACUS11 KWNS 301610 SWOMCD SPC MCD 301607 NCZ000-VAZ000-MDZ000-301800- MESOSCALE DISCUSSION 2149 NWS STORM PREDICTION CENTER NORMAN OK 1107 AM CDT MON AUG 30 2004 AREAS AFFECTED...SRN/ERN VA...NERN NC...SRN MD CONCERNING...SEVERE THUNDERSTORM POTENTIAL VALID 301607Z - 301800Z CONVECTION IS BEGINNING TO INCREASE OVER SRN VA IN ADVANCE OF TD GASTON. 1630Z OUTLOOK WILL BE UPGRADED TO SLIGHT RISK...AND AREA WILL BE MONITORED FOR POSSIBLE WW. VISIBLE IMAGERY SHOWS CONVECTIVE CELLS WITH CG LIGHTNING DEVELOPING OVER SRN VA TO THE NORTH OF THE CIRCULATION ASSOCIATED WITH TD GASTON...WITHIN BAND OF ENHANCED LOW LEVEL CONVERGENCE EXTENDING FROM SOUTH CENTRAL VA INTO THE TIDEWATER AREA. STRONGER DIURNAL HEATING HAS OCCURRED ALONG THE PERIPHERY OF THE DENSE CLOUDS ATTENDING THE CIRCULATION CENTER...RESULTING IN SUBSTANTIAL DESTABILIZATION WITH SBCAPE AROUND 3000 J/KG. LATEST VAD WIND PROFILE FROM AKQ SHOW STRONG WINDS IN THE LOWEST 3-4 KM AGL THAT VEER WITH HEIGHT...PROVIDING A VERTICAL SHEAR/HELICITY SUPPORTIVE OF SMALL SUPERCELLS. CELLS ARE EXPECTED TO CONTINUE TO DEVELOP INTO THE AFTERNOON HOURS...POSSIBLY EXTENDING SWD INTO NERN NC...WITH POTENTIAL FOR BRIEF TORNADOES TO DEVELOP. ..WEISS.. 08/30/2004 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...AKQ...MHX...LWX...RNK... 35567681 36347696 36727767 36727826 37187862 37847835 38437769 38417639 37557594 36557576 35817551 35367630
SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 30, 6:40 PM EDT | Mesoscale Discussion | SPC | Saint Mary's, Somerset, Wicomico, Worcester | 2 hr |
| Aug 29, 9:13 PM EDT | Mesoscale Discussion | SPC | Bladen, Brunswick, Columbus, Craven, Cumberland, Duplin and 18 more | 92 min |
| Aug 30, 12:50 PM EDT | Tornado Watch | SPC | Currituck | 7 hr |
| Aug 30, 3:06 PM EDT | Mesoscale Discussion | SPC | Accomack, Amelia, Brunswick, Caroline, Charles City, Chesterfield and 45 more | 114 min |
Nearby
Mesoscale Discussions in Virginia, 2004Mesoscale Discussions in North Carolina, 2004Mesoscale Discussions in Maryland, 2004Every mesoscale discussion in 2004
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.