Alert archive / Virginia / Severe Thunderstorm Watches in 2020
Severe Thunderstorm Watch 451
The Storm Prediction Center issued this severe thunderstorm watch at Aug 25, 2020, 3:34 PM EDT for 5 states. It was in force for 7 hr.
The area
The outline as issued.
The facts
- Issued
- Aug 25, 2020, 3:34 PM EDT (19:34 UTC)
- Expired
- Aug 25, 2020, 11:00 PM EDT
- In force
- 7 hr
- Issued by
- the Storm Prediction Center
- Largest hail expected
- 1.5 in
- Strongest gust expected
- 60 kt
All 151 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, 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, Morris County, NJ, Ocean County, NJ, Salem County, NJ, Somerset County, NJ, Sussex County, NJ, Warren County, NJ, Accomack County, VA, Albemarle County, VA, Alleghany County, VA, Amherst County, VA, Appomattox County, VA, Arlington County, VA, Augusta County, VA, Bath County, VA, Bedford County, VA, Bland County, VA, Botetourt County, VA, Buchanan County, VA, Buckingham County, VA, Campbell County, VA, Caroline County, VA, City of Alexandria, VA, City of Buena Vista, VA, City of Charlottesville, VA, City of Covington, VA, City of Fairfax, VA, City of Falls Church, VA, City of Fredericksburg, VA, City of Harrisonburg, VA, City of Lexington, VA, City of Lynchburg, VA, City of Manassas, VA, City of Manassas Park, VA, City of Radford, VA, City of Roanoke, VA, City of Salem, VA, City of Staunton, VA, City of Waynesboro, VA, City of Winchester, VA, Clarke County, VA, Craig County, VA, Culpeper County, VA, Cumberland County, VA, Essex County, VA, Fairfax County, VA, Fauquier County, VA, Fluvanna County, VA, Frederick County, VA, Giles County, VA, Goochland 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, Middlesex County, VA, Montgomery County, VA, Nelson County, VA, Northumberland County, VA, Orange County, VA, Page County, VA, Prince William County, VA, Pulaski County, VA, Rappahannock County, VA, Richmond County, VA, Roanoke County, VA, Rockbridge County, VA, Rockingham County, VA, Shenandoah County, VA, Spotsylvania County, VA, Stafford County, VA, Tazewell County, VA, Warren County, VA, Westmoreland County, VA, Barbour County, WV, Berkeley County, WV, Boone County, WV, Braxton County, WV, Cabell County, WV, Calhoun County, WV, Clay County, WV, Fayette County, WV, Gilmer County, WV, Grant County, WV, Greenbrier County, WV, Hampshire County, WV, Hardy County, WV, Jefferson County, WV, Kanawha County, WV, Lewis County, WV, Lincoln County, WV, Logan County, WV, McDowell County, WV, Mercer County, WV, Mineral County, WV, Mingo County, WV, Monroe County, WV, Morgan County, WV, Nicholas County, WV, Pendleton County, WV, Pocahontas County, WV, Putnam County, WV, Raleigh County, WV, Randolph County, WV, Roane County, WV, Summers County, WV, Upshur County, WV, Wayne County, WV, Webster County, WV, Wyoming County, WV
The radar
The Sterling radar (KLWX), 133 km from the middle of the area, began a volume at 19:36 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
- 5%
- One or more EF2 to EF5 tornadoes
- 2%
- Ten or more severe wind reports
- 60%
- One or more gusts of 65 knots or more
- 20%
- Ten or more severe hail reports
- 20%
- One or more hailstones of 2 inches or more
- 10%
- Six or more combined severe hail and wind reports
- 80%
Warnings issued inside it
39 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 25, 4:12 PM EDT | Severe Thunderstorm Warning | LWX | Allegany, Washington | 48 min |
| Aug 25, 4:40 PM EDT | Flash Flood Warning | RLX | Upshur | 5 hr |
| Aug 25, 4:49 PM EDT | Severe Thunderstorm Warning | PHI | Sussex | 26 min |
| Aug 25, 4:50 PM EDT | Severe Thunderstorm Warning | LWX | Allegany, Washington | 40 min |
| Aug 25, 4:52 PM EDT | Severe Thunderstorm Warning | LWX | Allegany | 38 min |
| Aug 25, 4:54 PM EDT | Severe Thunderstorm Warning | RLX | Barbour, Harrison, Randolph, Taylor | 36 min |
| Aug 25, 5:19 PM EDT | Severe Thunderstorm Warning | LWX | Hampshire | 41 min |
| Aug 25, 5:24 PM EDT | Severe Thunderstorm Warning | LWX | Clarke, Frederick | 51 min |
| Aug 25, 5:24 PM EDT | Severe Thunderstorm Warning | RLX | Calhoun, Jackson, Ritchie, Roane, Wirt | 51 min |
| Aug 25, 5:26 PM EDT | Severe Thunderstorm Warning | LWX | Grant | 33 min |
| Aug 25, 5:27 PM EDT | Severe Thunderstorm Warning | LWX | Mineral | 18 min |
| Aug 25, 5:35 PM EDT | Severe Thunderstorm Warning | PHI | New Castle | 40 min |
| Aug 25, 5:41 PM EDT | Severe Thunderstorm Warning | LWX | Frederick, Shenandoah, City of Winchester | 49 min |
| Aug 25, 5:44 PM EDT | Severe Thunderstorm Warning | RLX | Jackson, Mason, Putnam | 46 min |
| Aug 25, 5:50 PM EDT | Severe Thunderstorm Warning | PHI | New Castle | 40 min |
| Aug 25, 5:57 PM EDT | Severe Thunderstorm Warning | PHI | Warren | 18 min |
| Aug 25, 6:06 PM EDT | Severe Thunderstorm Warning | LWX | Clarke, Fauquier, Frederick, Loudoun, Warren, City of Winchester | 39 min |
| Aug 25, 6:10 PM EDT | Severe Thunderstorm Warning | PHI | Cumberland, Salem | 50 min |
| Aug 25, 6:15 PM EDT | Severe Thunderstorm Warning | RLX | Clay, Kanawha, Putnam, Roane | 45 min |
| Aug 25, 6:27 PM EDT | Severe Thunderstorm Warning | LWX | Fairfax, Fauquier, Loudoun, Prince William, City of Manassas, City of Manassas Park | 48 min |
| Aug 25, 6:31 PM EDT | Severe Thunderstorm Warning | PHI | Kent, New Castle | 19 min |
| Aug 25, 6:42 PM EDT | Severe Thunderstorm Warning | LWX | Fauquier, Loudoun, Rappahannock, Warren | 48 min |
| Aug 25, 6:56 PM EDT | Severe Thunderstorm Warning | PHI | Cape May, Cumberland | 43 min |
| Aug 25, 6:57 PM EDT | Severe Thunderstorm Warning | LWX | Arlington, Fairfax, City of Alexandria, City of Fairfax, City of Falls Church | 48 min |
| Aug 25, 7:00 PM EDT | Severe Thunderstorm Warning | RLX | Fayette, Kanawha | 45 min |
| Aug 25, 7:02 PM EDT | Severe Thunderstorm Warning | RNK | Greenbrier | 73 min |
| Aug 25, 7:08 PM EDT | Severe Thunderstorm Warning | LWX | Culpeper, Fauquier, Prince William, Stafford, City of Manassas, City of Manassas Park | 52 min |
| Aug 25, 7:11 PM EDT | Severe Thunderstorm Warning | LWX | Prince George's | 49 min |
| Aug 25, 7:28 PM EDT | Flash Flood Warning | RLX | Kanawha | 3 hr |
| Aug 25, 7:36 PM EDT | Severe Thunderstorm Warning | LWX | Charles | 39 min |
| Aug 25, 7:51 PM EDT | Severe Thunderstorm Warning | LWX | Anne Arundel, Calvert, Prince George's | 39 min |
| Aug 25, 8:09 PM EDT | Severe Thunderstorm Warning | RLX | Boone, Kanawha, Logan, Raleigh, Wyoming | 51 min |
| Aug 25, 8:28 PM EDT | Severe Thunderstorm Warning | PHI | Caroline, Queen Anne's, Talbot | 47 min |
| Aug 25, 8:29 PM EDT | Severe Thunderstorm Warning | AKQ | Dorchester | 46 min |
| Aug 25, 8:33 PM EDT | Severe Thunderstorm Warning | PHI | Mercer, Middlesex, Monmouth, Ocean, Somerset | 27 min |
| Aug 25, 8:51 PM EDT | Severe Thunderstorm Warning | RLX | Raleigh, Wyoming | 24 min |
| Aug 25, 9:08 PM EDT | Severe Thunderstorm Warning | AKQ | Dorchester, Somerset, Wicomico | 52 min |
| Aug 25, 9:12 PM EDT | Severe Thunderstorm Warning | PHI | Kent, Sussex | 48 min |
| Aug 25, 9:47 PM EDT | Severe Thunderstorm Warning | AKQ | Somerset, Wicomico, Worcester | 43 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, 7.6 hours before the alert went out and 138 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
- 573 J/kg
- Mixed-layer CIN
- -96 J/kg
- Mixed-layer LCL
- 1117 m above ground
- 0-6 km bulk shear
- 38 kt
- 0-1 km storm-relative helicity
- 176 m²/s²
- 0-3 km storm-relative helicity
- 176 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.8
SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 25, 3:10 PM EDT | Mesoscale Discussion | SPC | Kent, New Castle | 95 min |
| Aug 25, 7:07 PM EDT | Mesoscale Discussion | SPC | Kent, New Castle, Sussex | 113 min |
| Aug 25, 1:21 PM EDT | Severe Thunderstorm Watch | SPC | Garrett | 6 hr |
| Aug 25, 4:35 PM EDT | Mesoscale Discussion | SPC | Allegany, Garrett | 85 min |
| Aug 25, 3:12 PM EDT | Severe Thunderstorm Watch | SPC | Bergen, Essex, Hudson, Passaic, Union | 5 hr |
| Aug 25, 6:11 PM EDT | Mesoscale Discussion | SPC | Bergen, Essex, Hudson, Hunterdon, Middlesex, Monmouth and 6 more | 2 hr |
| Aug 25, 12:02 PM EDT | Mesoscale Discussion | SPC | Hancock | 118 min |
Nearby
Severe Thunderstorm Watches in Virginia, 2020Severe Thunderstorm Watches in West Virginia, 2020Severe Thunderstorm Watches in Maryland, 2020Every severe thunderstorm watch in 2020
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.