Severe Thunderstorm Watch 425

Issued

Aug 11, 2021, 2:02 PM EDT (18:02 UTC)

Expired

Aug 11, 2021, 8:19 PM EDT

In force

6 hr

Issued by

the Storm Prediction Center

Largest hail expected

1 in

Strongest gust expected

50 kt

The Sterling radar (KLWX), 61 km from the middle of the area, began a volume at 18:02 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.

Two or more tornadoes

5%

One or more EF2 to EF5 tornadoes

2%

Ten or more severe wind reports

50%

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

70%

• Mesoscale Discussion 1479 Severe potential...watch possibleAug 11, 1:01 PM EDT
• Mesoscale Discussion 1484 Severe thunderstorm watch 425Aug 11, 3:47 PM EDT
• Mesoscale Discussion 1490 Severe thunderstorm watch 427Aug 11, 6:44 PM EDT

577 
WWUS20 KWNS 111759
SEL5  
SPC WW 111759
DCZ000-MDZ000-VAZ000-WVZ000-CWZ000-120100-

URGENT - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Watch Number 425
NWS Storm Prediction Center Norman OK
200 PM EDT Wed Aug 11 2021

The NWS Storm Prediction Center has issued a

* Severe Thunderstorm Watch for portions of 
  District Of Columbia
  Maryland
  Much of central and northern Virginia
  The eastern West Virginia Panhandle
  Coastal Waters

* Effective this Wednesday afternoon and evening from 200 PM
  until 900 PM EDT.

* Primary threats include...
  Scattered damaging wind gusts to 60 mph possible
  Isolated large hail events to 1 inch in diameter possible

SUMMARY...Scattered pulse-severe storms will form through the
afternoon in a broken band east of the Blue Ridge, and storms will
drift eastward through this evening.  The strongest updrafts may
produce marginally severe hail, but the main threat will be
occasional wind damage with downbursts.

The severe thunderstorm watch area is approximately along and 65
statute miles east and west of a line from 40 miles north northwest
of Baltimore MD to 5 miles west of Danville VA. For a complete
depiction of the watch see the associated watch outline update
(WOUS64 KWNS WOU5).

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 423...WW 424...

AVIATION...A few severe thunderstorms with hail surface and aloft to
1 inch. Extreme turbulence and surface wind gusts to 50 knots. A few
cumulonimbi with maximum tops to 500. Mean storm motion vector
27010.

...Thompson

Severe Thunderstorm Watches in Virginia, 2021Severe Thunderstorm Watches in Maryland, 2021Severe Thunderstorm Watches in West Virginia, 2021Every severe thunderstorm watch in 2021

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.