Alert archive / West Virginia / Severe Thunderstorm Watches in 2021
Severe Thunderstorm Watch 271
The Storm Prediction Center issued this severe thunderstorm watch at Jun 14, 2021, 3:59 PM EDT for Allegany County, Garrett County, Washington County, Maryland; 6 counties in Virginia; 8 counties in West Virginia. It was in force for 6 hr.
The area
The outline as issued.
The facts
- Issued
- Jun 14, 2021, 3:59 PM EDT (19:59 UTC)
- Expired
- Jun 14, 2021, 10:11 PM EDT
- In force
- 6 hr
- Issued by
- the Storm Prediction Center
- Largest hail expected
- 1.5 in
- Strongest gust expected
- 55 kt
Counties Allegany County, MD, Garrett County, MD, Washington County, MD, City of Winchester, VA, Clarke County, VA, Frederick County, VA, Page County, VA, Shenandoah 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), 120 km from the middle of the area, began a volume at 20:02 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
- 60%
Warnings issued inside it
1 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jun 14, 5:53 PM EDT | Severe Thunderstorm Warning | LWX | Garrett | 38 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, 8.0 hours before the alert went out and 128 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
- 2 J/kg
- Mixed-layer CIN
- -447 J/kg
- Mixed-layer LCL
- 1007 m above ground
- 0-6 km bulk shear
- 33 kt
- 0-1 km storm-relative helicity
- 31 m²/s²
- 0-3 km storm-relative helicity
- 87 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
409 WWUS20 KWNS 141956 SEL1 SPC WW 141956 MDZ000-VAZ000-WVZ000-150100- URGENT - IMMEDIATE BROADCAST REQUESTED Severe Thunderstorm Watch Number 271 NWS Storm Prediction Center Norman OK 400 PM EDT Mon Jun 14 2021 The NWS Storm Prediction Center has issued a * Severe Thunderstorm Watch for portions of Maryland Panhandle Northern Virginia Eastern West Virginia Panhandle * Effective this Monday afternoon and evening from 400 PM until 900 PM EDT. * Primary threats include... Scattered damaging wind gusts to 65 mph possible Isolated large hail events to 1.5 inches in diameter possible SUMMARY...Discrete cells should spread east-southeast from southwest Pennsylvania and may develop south across the eastern West Virginia Panhandle. The severe thunderstorm watch area is approximately along and 45 statute miles north and south of a line from 75 miles west of Martinsburg WV to 20 miles south southeast of Martinsburg WV. For a complete depiction of the watch see the associated watch outline update (WOUS64 KWNS WOU1). PRECAUTIONARY/PREPAREDNESS ACTIONS... REMEMBER...A Severe Thunderstorm Watch means conditions are favorable for severe thunderstorms in and close to the watch area. Persons in these areas should be on the lookout for threatening weather conditions and listen for later statements and possible warnings. Severe thunderstorms can and occasionally do produce tornadoes. && OTHER WATCH INFORMATION...CONTINUE...WW 269...WW 270... AVIATION...A few severe thunderstorms with hail surface and aloft to 1.5 inches. Extreme turbulence and surface wind gusts to 55 knots. A few cumulonimbi with maximum tops to 500. Mean storm motion vector 30030. ...Grams
SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jun 14, 11:31 AM EDT | Mesoscale Discussion | SPC | Allegany, Garrett | 89 min |
| Jun 14, 3:55 PM EDT | Mesoscale Discussion | SPC | Allegany, Garrett, Washington | 65 min |
| Jun 14, 6:41 PM EDT | Mesoscale Discussion | SPC | Anne Arundel, Baltimore, Calvert, Caroline, Carroll, Cecil and 13 more | 2 hr |
| Jun 14, 7:29 PM EDT | Severe Thunderstorm Watch | SPC | Anne Arundel, Baltimore, Calvert, Caroline, Carroll, Cecil and 15 more | 6 hr |
| Jun 14, 7:37 PM EDT | Mesoscale Discussion | SPC | Allegany, Garrett | 113 min |
| Jun 14, 11:46 AM EDT | Severe Thunderstorm Watch | SPC | Allegheny, Armstrong, Beaver, Bedford, Blair, Butler and 20 more | 6 hr |
| Jun 14, 1:40 PM EDT | Mesoscale Discussion | SPC | Adams, Berks, Bucks, Carbon, Chester, Columbia and 15 more | 3 hr |
| Jun 14, 2:06 PM EDT | Severe Thunderstorm Watch | SPC | Adams, Berks, Bucks, Carbon, Chester, Columbia and 22 more | 9 hr |
| Jun 14, 2:48 PM EDT | Mesoscale Discussion | SPC | Susquehanna | 2 hr |
| Jun 14, 3:25 PM EDT | Mesoscale Discussion | SPC | Fayette, Greene, Somerset, Washington, Westmoreland | 95 min |
| Jun 14, 6:18 PM EDT | Mesoscale Discussion | SPC | Berks, Bucks, Chester, Delaware, Lancaster, Lehigh and 3 more | 117 min |
| Jun 14, 4:52 PM EDT | Severe Thunderstorm Watch | SPC | Barbour, Doddridge, Harrison, Lewis, Marion, Marshall and 11 more | 6 hr |
Nearby
Severe Thunderstorm Watches in West Virginia, 2021Severe Thunderstorm Watches in Virginia, 2021Severe Thunderstorm Watches in Maryland, 2021Every severe thunderstorm watch in 2021
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.