Alert archive / Virginia / Severe Thunderstorm Watches in 2011
Severe Thunderstorm Watch 412
The Storm Prediction Center issued this severe thunderstorm watch at Jun 1, 2011, 2:24 PM EDT for 5 states. It was in force for 7 hr.
The area
The outline as issued.
The facts
- Issued
- Jun 1, 2011, 2:24 PM EDT (18:24 UTC)
- Expired
- Jun 1, 2011, 8:59 PM EDT
- In force
- 7 hr
- Issued by
- the Storm Prediction Center
- Largest hail expected
- 2 in
- Strongest gust expected
- 60 kt
All 83 counties
Kent County, DE, New Castle County, DE, Sussex County, DE, Allegany County, MD, Anne Arundel County, MD, Baltimore County, MD, Calvert County, MD, Caroline County, MD, Carroll County, MD, Cecil County, MD, Charles County, MD, City of Baltimore, MD, Dorchester County, MD, Frederick County, MD, Harford County, MD, Howard County, MD, Kent County, MD, Montgomery County, MD, Prince George's County, MD, Queen Anne's County, MD, Saint Mary's County, MD, Somerset County, MD, Talbot County, MD, Washington County, MD, Wicomico County, MD, Worcester County, MD, Atlantic County, NJ, Cape May County, NJ, Cumberland County, NJ, Salem County, NJ, Albemarle County, VA, Arlington County, VA, Augusta County, VA, Caroline County, VA, City of Alexandria, VA, City of Charlottesville, VA, City of Fairfax, VA, City of Falls Church, VA, City of Fredericksburg, VA, City of Harrisonburg, VA, City of Manassas, VA, City of Manassas Park, VA, City of Staunton, VA, City of Waynesboro, VA, City of Winchester, VA, Clarke County, VA, Culpeper County, VA, Essex County, VA, Fairfax County, VA, Fauquier County, VA, Fluvanna County, VA, Frederick County, VA, Greene County, VA, Hanover County, VA, Highland County, VA, King and Queen County, VA, King George County, VA, King William County, VA, Lancaster County, VA, Loudoun County, VA, Louisa County, VA, Madison County, VA, Nelson County, VA, Northumberland County, VA, Orange County, VA, Page County, VA, Prince William County, VA, Rappahannock County, VA, Richmond County, VA, Rockingham County, VA, Shenandoah County, VA, Spotsylvania County, VA, Stafford County, VA, Warren County, VA, Westmoreland County, VA, Berkeley County, WV, Grant County, WV, Hampshire County, WV, Hardy County, WV, Jefferson County, WV, Mineral County, WV, Morgan County, WV, Pendleton County, WV
The radar
The Sterling radar (KLWX), 8 km from the middle of the area, began a volume at 18:27 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.
What SPC expected
The probabilities SPC published with the watch, for the watch area over its life.
- Two or more tornadoes
- 20%
- One or more EF2 to EF5 tornadoes
- 5%
- Ten or more severe wind reports
- 50%
- One or more gusts of 65 knots or more
- 30%
- Ten or more severe hail reports
- 70%
- One or more hailstones of 2 inches or more
- 20%
- Six or more combined severe hail and wind reports
- 90%
Warnings issued inside it
16 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jun 1, 3:06 PM EDT | Severe Thunderstorm Warning | PHI | Talbot | 54 min |
| Jun 1, 3:07 PM EDT | Severe Thunderstorm Warning | LWX | Washington | 38 min |
| Jun 1, 4:41 PM EDT | Severe Thunderstorm Warning | LWX | Greene, Madison, Page, Rockingham | 49 min |
| Jun 1, 4:47 PM EDT | Severe Thunderstorm Warning | LWX | Harford | 22 min |
| Jun 1, 4:53 PM EDT | Severe Thunderstorm Warning | LWX | Culpeper, Madison, Orange | 67 min |
| Jun 1, 4:55 PM EDT | Severe Thunderstorm Warning | PHI | New Castle | 26 min |
| Jun 1, 5:32 PM EDT | Severe Thunderstorm Warning | LWX | Charles, Prince George's | 42 min |
| Jun 1, 5:39 PM EDT | Severe Thunderstorm Warning | LWX | Anne Arundel, Prince George's | 66 min |
| Jun 1, 6:22 PM EDT | Severe Thunderstorm Warning | LWX | Prince George's | 38 min |
| Jun 1, 6:34 PM EDT | Severe Thunderstorm Warning | LWX | Orange, Spotsylvania | 41 min |
| Jun 1, 6:39 PM EDT | Severe Thunderstorm Warning | LWX | Prince George's | 51 min |
| Jun 1, 6:54 PM EDT | Severe Thunderstorm Warning | LWX | Anne Arundel, Prince George's | 46 min |
| Jun 1, 7:06 PM EDT | Severe Thunderstorm Warning | LWX | Spotsylvania | 39 min |
| Jun 1, 7:16 PM EDT | Severe Thunderstorm Warning | LWX | Orange, Spotsylvania, Stafford, City of Fredericksburg | 35 min |
| Jun 1, 7:28 PM EDT | Severe Thunderstorm Warning | LWX | Anne Arundel, Calvert, Prince George's | 22 min |
| Jun 1, 7:33 PM EDT | Severe Thunderstorm Warning | AKQ | Caroline, Hanover, Louisa | 26 min |
Discussions around it
SPC mesoscale discussions over the same counties from four hours before the watch to its end.
The nearest sounding before it
Washington/Dulle, VA (KIAD), launched 12:00Z, 6.4 hours before the alert went out and 2 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
- 3637 J/kg
- Mixed-layer CIN
- -50 J/kg
- Mixed-layer LCL
- 975 m above ground
- 0-6 km bulk shear
- 20 kt
- 0-1 km storm-relative helicity
- 54 m²/s²
- 0-3 km storm-relative helicity
- 67 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 2.1
SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jun 1, 1:37 PM EDT | Mesoscale Discussion | SPC | Kent, New Castle | 83 min |
| Jun 1, 6:27 PM EDT | Mesoscale Discussion | SPC | Kent, New Castle, Sussex | 93 min |
| Jun 1, 12:26 PM EDT | Mesoscale Discussion | SPC | Bergen, Essex, Hudson, Hunterdon, Middlesex, Morris and 5 more | 64 min |
| Jun 1, 12:58 PM EDT | Tornado Watch | SPC | Bergen, Burlington, Camden, Essex, Gloucester, Hudson and 11 more | 7 hr |
| Jun 1, 7:09 PM EDT | Mesoscale Discussion | SPC | Bergen, Essex, Hudson, Mercer, Middlesex, Monmouth and 5 more | 96 min |
| Jun 1, 4:35 PM EDT | Mesoscale Discussion | SPC | Alleghany, Bland, Botetourt, Buchanan, Carroll, Craig and 26 more | 85 min |
Nearby
Severe Thunderstorm Watches in Virginia, 2011Severe Thunderstorm Watches in Maryland, 2011Severe Thunderstorm Watches in West Virginia, 2011Every severe thunderstorm watch in 2011
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.