Alert archive / Virginia / Mesoscale Discussions in 2008
Mesoscale Discussion 669
The Storm Prediction Center issued this mesoscale discussion at Apr 20, 2008, 11:20 AM EDT for 9 counties in Virginia. It was in force for 2 hr.
The area
The outline as issued.
The facts
- Issued
- Apr 20, 2008, 11:20 AM EDT (15:20 UTC)
- Expired
- Apr 20, 2008, 1:45 PM EDT
- In force
- 2 hr
- Issued by
- the Storm Prediction Center
Counties Chesterfield County, VA, City of Colonial Heights, VA, City of Emporia, VA, City of Hopewell, VA, City of Petersburg, VA, City of Richmond, VA, Dinwiddie County, VA, Greensville County, VA, Hanover County, VA
The radar
The Norfolk radar (KAKQ), 53 km from the middle of the area, began a volume at 15:19 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
Roanoke, VA (KRNK), launched 12:00Z, 3.3 hours before the alert went out and 178 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
- 671 m above ground
- 0-6 km bulk shear
- 56 kt
- 0-1 km storm-relative helicity
- -28 m²/s²
- 0-3 km storm-relative helicity
- -4 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted, in the capitals the NWS used until 2016.
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</html>SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Apr 19, 9:00 PM EDT | Mesoscale Discussion | SPC | Alleghany, Amherst, Bath, Bedford, Botetourt, Campbell and 23 more | 60 min |
| Apr 20, 1:14 PM EDT | Mesoscale Discussion | SPC | Amelia, Appomattox, Bedford, Brunswick, Campbell, Charlotte and 21 more | 2 hr |
| Apr 20, 1:47 PM EDT | Severe Thunderstorm Watch | SPC | Brunswick, Caroline, Charles City, Charlotte, Chesterfield, Dinwiddie and 43 more | 8 hr |
| Apr 20, 4:20 PM EDT | Mesoscale Discussion | SPC | Brunswick, Dinwiddie, Greensville, Halifax, Isle of Wight, Lunenburg and 19 more | 85 min |
| Apr 20, 6:44 PM EDT | Mesoscale Discussion | SPC | Caroline, Charles City, Essex, Hanover, Henrico, James City and 15 more | 61 min |
| Apr 20, 7:14 PM EDT | Mesoscale Discussion | SPC | Amelia, Brunswick, Caroline, Charles City, Charlotte, Chesterfield and 42 more | 61 min |
Nearby
Mesoscale Discussions in Virginia, 2008Every mesoscale discussion in 2008
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.