Alert archive / Virginia / Tornado Watches in 2020
Tornado Watch 485
The Storm Prediction Center issued this tornado watch at Sep 3, 2020, 3:42 PM EDT for 6 states. It was in force for 6 hr.
The area
The outline as issued.
The facts
- Issued
- Sep 3, 2020, 3:42 PM EDT (19:42 UTC)
- Expired
- Sep 3, 2020, 9:40 PM EDT
- In force
- 6 hr
- Issued by
- the Storm Prediction Center
- Largest hail expected
- 1 in
- Strongest gust expected
- 65 kt
All 74 counties
Kent County, DE, New Castle County, DE, Sussex County, DE, 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, Ocean County, NJ, Salem County, NJ, Adams County, PA, Berks County, PA, Bucks County, PA, Chester County, PA, Cumberland County, PA, Dauphin County, PA, Delaware County, PA, Franklin County, PA, Lancaster County, PA, Lebanon County, PA, Lehigh County, PA, Montgomery County, PA, Philadelphia County, PA, York County, PA, Albemarle County, VA, Arlington 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 Manassas, VA, City of Manassas Park, VA, City of Winchester, VA, Clarke County, VA, Culpeper County, VA, Fairfax County, VA, Fauquier County, VA, Frederick County, VA, Greene County, VA, King George County, VA, Loudoun County, VA, Madison County, VA, Orange County, VA, Prince William County, VA, Rappahannock County, VA, Spotsylvania County, VA, Stafford County, VA, Warren County, VA, Berkeley County, WV, Jefferson County, WV
The radar
The Dover AFB radar (KDOX), 80 km from the middle of the area, began a volume at 19:46 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
- 60%
- One or more EF2 to EF5 tornadoes
- 20%
- Ten or more severe wind reports
- 70%
- One or more gusts of 65 knots or more
- 30%
- Ten or more severe hail reports
- 10%
- One or more hailstones of 2 inches or more
- 5%
- Six or more combined severe hail and wind reports
- 80%
Warnings issued inside it
17 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Sep 3, 3:43 PM EDT | Tornado Warning | LWX | Carroll, Frederick, Howard | 19 min |
| Sep 3, 4:07 PM EDT | Severe Thunderstorm Warning | LWX | Montgomery | 38 min |
| Sep 3, 4:31 PM EDT | Severe Thunderstorm Warning | LWX | Baltimore, Carroll, Howard, City of Baltimore | 44 min |
| Sep 3, 4:36 PM EDT | Severe Thunderstorm Warning | LWX | Howard, Montgomery, Prince George's | 54 min |
| Sep 3, 4:36 PM EDT | Tornado Warning | LWX | Baltimore, Carroll, Howard, City of Baltimore | 24 min |
| Sep 3, 4:43 PM EDT | Tornado Warning | LWX | Howard, Montgomery, Prince George's | 32 min |
| Sep 3, 5:05 PM EDT | Tornado Warning | LWX | Baltimore, Harford, City of Baltimore | 40 min |
| Sep 3, 5:10 PM EDT | Tornado Warning | LWX | Montgomery, Prince George's | 35 min |
| Sep 3, 5:16 PM EDT | Severe Thunderstorm Warning | LWX | Anne Arundel, Prince George's | 59 min |
| Sep 3, 5:27 PM EDT | Severe Thunderstorm Warning | LWX | Anne Arundel, Calvert, Montgomery, Prince George's | 63 min |
| Sep 3, 5:29 PM EDT | Flash Flood Warning | LWX | Montgomery, Prince George's | 3 hr |
| Sep 3, 5:30 PM EDT | Severe Thunderstorm Warning | CTP | Lancaster, York | 30 min |
| Sep 3, 5:47 PM EDT | Severe Thunderstorm Warning | PHI | Caroline, Kent, Queen Anne's, Talbot | 73 min |
| Sep 3, 5:55 PM EDT | Tornado Warning | LWX | Anne Arundel | 14 min |
| Sep 3, 6:25 PM EDT | Severe Thunderstorm Warning | LWX | Fairfax, Prince William, City of Manassas, City of Manassas Park | 50 min |
| Sep 3, 6:48 PM EDT | Severe Thunderstorm Warning | PHI | Kent, Sussex | 57 min |
| Sep 3, 7:40 PM EDT | Severe Thunderstorm Warning | PHI | Sussex | 65 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, 7.7 hours before the alert went out and 131 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
- 12 J/kg
- Mixed-layer CIN
- -77 J/kg
- Mixed-layer LCL
- 1011 m above ground
- 0-6 km bulk shear
- 26 kt
- 0-1 km storm-relative helicity
- 2 m²/s²
- 0-3 km storm-relative helicity
- 73 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Sep 2, 8:20 PM EDT | Mesoscale Discussion | SPC | Kent, New Castle | 115 min |
| Sep 3, 3:06 PM EDT | Mesoscale Discussion | SPC | Kent, New Castle, Sussex | 114 min |
| Sep 3, 6:18 PM EDT | Mesoscale Discussion | SPC | Kent, Sussex | 117 min |
Nearby
Tornado Watches in Virginia, 2020Tornado Watches in Maryland, 2020Tornado Watches in Pennsylvania, 2020Every tornado 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.