Alert archive / Virginia / Severe Thunderstorm Watches in 2017
Severe Thunderstorm Watch 186
The Storm Prediction Center issued this severe thunderstorm watch at May 1, 2017, 5:54 PM EDT for 4 states. It was in force for 5 hr.
The area
The outline as issued.
The facts
- Issued
- May 1, 2017, 5:54 PM EDT (21:54 UTC)
- Expired
- May 1, 2017, 10:58 PM EDT
- In force
- 5 hr
- Issued by
- the Storm Prediction Center
- Largest hail expected
- 1 in
- Strongest gust expected
- 60 kt
All 111 counties
Allegany County, MD, Baltimore County, MD, Carroll County, MD, Charles County, MD, City of Baltimore, MD, Frederick County, MD, Harford County, MD, Howard County, MD, Montgomery County, MD, Prince George's County, MD, Washington County, MD, Alamance County, NC, Anson County, NC, Caswell County, NC, Chatham County, NC, Davidson County, NC, Durham County, NC, Forsyth County, NC, Franklin County, NC, Granville County, NC, Guilford County, NC, Harnett County, NC, Hoke County, NC, Lee County, NC, Montgomery County, NC, Moore County, NC, Orange County, NC, Person County, NC, Randolph County, NC, Richmond County, NC, Rockingham County, NC, Scotland County, NC, Stanly County, NC, Vance County, NC, Wake County, NC, Warren County, NC, Albemarle County, VA, Amelia County, VA, Amherst County, VA, Appomattox County, VA, Arlington County, VA, Augusta County, VA, Bedford County, VA, Brunswick County, VA, Buckingham County, VA, Campbell County, VA, Caroline County, VA, Charlotte County, VA, Chesterfield County, VA, City of Alexandria, VA, City of Buena Vista, VA, City of Charlottesville, VA, City of Danville, 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 Martinsville, VA, City of Richmond, VA, City of Staunton, VA, City of Waynesboro, VA, City of Winchester, VA, Clarke County, VA, Culpeper County, VA, Cumberland County, VA, Dinwiddie County, VA, Fairfax County, VA, Fauquier County, VA, Fluvanna County, VA, Franklin County, VA, Frederick County, VA, Goochland County, VA, Greene County, VA, Halifax County, VA, Hanover County, VA, Henrico County, VA, Henry County, VA, Highland County, VA, King George County, VA, Loudoun County, VA, Louisa County, VA, Lunenburg County, VA, Madison County, VA, Mecklenburg County, VA, Nelson County, VA, Nottoway County, VA, Orange County, VA, Page County, VA, Pittsylvania County, VA, Powhatan County, VA, Prince Edward County, VA, Prince William County, VA, Rappahannock County, VA, Rockbridge County, VA, Rockingham County, VA, Shenandoah County, VA, Spotsylvania County, VA, Stafford County, VA, Warren 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), 164 km from the middle of the area, began a volume at 21:57 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
- 10%
- One or more EF2 to EF5 tornadoes
- 2%
- Ten or more severe wind reports
- 40%
- One or more gusts of 65 knots or more
- 10%
- 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
- 70%
Warnings issued inside it
6 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| May 1, 6:06 PM EDT | Severe Thunderstorm Warning | RAH | Davidson, Montgomery, Randolph, Stanly | 39 min |
| May 1, 6:19 PM EDT | Severe Thunderstorm Warning | RAH | Davidson, Randolph | 41 min |
| May 1, 6:25 PM EDT | Severe Thunderstorm Warning | RNK | Caswell, Rockingham | 65 min |
| May 1, 6:43 PM EDT | Severe Thunderstorm Warning | RAH | Anson, Montgomery, Richmond | 62 min |
| May 1, 6:57 PM EDT | Severe Thunderstorm Warning | RAH | Alamance, Chatham, Orange, Randolph | 51 min |
| May 1, 6:58 PM EDT | Severe Thunderstorm Warning | RNK | Caswell | 77 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
Roanoke, VA (KRNK), launched 12:00Z, 9.9 hours before the alert went out and 101 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
- 25 J/kg
- Mixed-layer CIN
- -10 J/kg
- Mixed-layer LCL
- 706 m above ground
- 0-6 km bulk shear
- 42 kt
- 0-1 km storm-relative helicity
- 255 m²/s²
- 0-3 km storm-relative helicity
- 277 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.5
SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| May 1, 11:59 AM EDT | Mesoscale Discussion | SPC | Garrett | 2 hr |
| May 1, 12:32 PM EDT | Tornado Watch | SPC | Garrett | 4 hr |
| May 1, 4:36 PM EDT | Mesoscale Discussion | SPC | Allegany | 84 min |
| May 1, 1:13 PM EDT | Mesoscale Discussion | SPC | Cleveland, Henderson, Polk, Rutherford, Transylvania | 92 min |
| May 1, 4:02 PM EDT | Mesoscale Discussion | SPC | Alexander, Anson, Cabarrus, Catawba, Davidson, Davie and 13 more | 118 min |
| May 1, 2:29 PM EDT | Mesoscale Discussion | SPC | Alleghany, Amherst, Appomattox, Augusta, Bath, Bedford and 30 more | 2 hr |
Nearby
Severe Thunderstorm Watches in Virginia, 2017Severe Thunderstorm Watches in North Carolina, 2017Severe Thunderstorm Watches in Maryland, 2017Every severe thunderstorm watch in 2017
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.