Severe Thunderstorm Watch 436

Issued

Aug 13, 2021, 1:11 PM EDT (17:11 UTC)

Expired

Aug 13, 2021, 8:00 PM EDT

In force

7 hr

Issued by

the Storm Prediction Center

Largest hail expected

1 in

Strongest gust expected

60 kt

The Sterling radar (KLWX), 23 km from the middle of the area, began a volume at 17:14 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

40%

One or more gusts of 65 knots or more

20%

Ten or more severe hail reports

5%

One or more hailstones of 2 inches or more

5%

Six or more combined severe hail and wind reports

50%

• Mesoscale Discussion 1510 Severe potential...watch possibleAug 13, 12:33 PM EDT
• Mesoscale Discussion 1515 Severe thunderstorm watch 436Aug 13, 4:48 PM EDT

400 
WWUS20 KWNS 131708
SEL6  
SPC WW 131708
DCZ000-MDZ000-PAZ000-VAZ000-WVZ000-CWZ000-140000-

URGENT - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Watch Number 436
NWS Storm Prediction Center Norman OK
110 PM EDT Fri Aug 13 2021

The NWS Storm Prediction Center has issued a

* Severe Thunderstorm Watch for portions of 
  District Of Columbia
  Maryland
  Southeast Pennsylvania
  Central and Northern Virginia
  Eastern Panhandle of West Virginia
  Coastal Waters

* Effective this Friday afternoon and evening from 110 PM until
  800 PM EDT.

* Primary threats include...
  Scattered damaging wind gusts to 70 mph possible

SUMMARY...Thunderstorms are expected to increase in coverage and
intensity through the afternoon and spread eastward across the watch
area.  While storms will likely be rather disorganized, the
strongest cells will be capable of locally damaging wind gusts.

The severe thunderstorm watch area is approximately along and 55
statute miles east and west of a line from 55 miles northeast of
Harrisburg PA to 55 miles south southwest of Lynchburg VA. For a
complete depiction of the watch see the associated watch outline
update (WOUS64 KWNS WOU6).

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.

&&

AVIATION...A few severe thunderstorms with hail surface and aloft to
1 inch. Extreme turbulence and surface wind gusts to 60 knots. A few
cumulonimbi with maximum tops to 500. Mean storm motion vector
28020.

...Hart

Severe Thunderstorm Watches in Virginia, 2021Severe Thunderstorm Watches in Maryland, 2021Severe Thunderstorm Watches in Pennsylvania, 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.