Tornado Watch 90

Issued

Apr 20, 2015, 3:08 PM EDT (19:08 UTC)

Expired

Apr 20, 2015, 11:57 PM EDT

In force

9 hr

Issued by

the Storm Prediction Center

Largest hail expected

2 in

Strongest gust expected

60 kt

The Sterling radar (KLWX), 30 km from the middle of the area, began a volume at 19:10 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

40%

One or more EF2 to EF5 tornadoes

20%

Ten or more severe wind reports

50%

One or more gusts of 65 knots or more

10%

Ten or more severe hail reports

50%

One or more hailstones of 2 inches or more

30%

Six or more combined severe hail and wind reports

70%

• Mesoscale Discussion 397Apr 20, 1:54 PM EDT
• Mesoscale Discussion 399Apr 20, 3:23 PM EDT
• Mesoscale Discussion 402Apr 20, 5:01 PM EDT
• Mesoscale Discussion 404Apr 20, 5:57 PM EDT
• Mesoscale Discussion 408Apr 20, 9:17 PM EDT

655 
WWUS20 KWNS 201904
SEL0  
SPC WW 201904
DCZ000-DEZ000-MDZ000-NJZ000-PAZ000-VAZ000-WVZ000-CWZ000-210200-

URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 90
NWS STORM PREDICTION CENTER NORMAN OK
305 PM EDT MON APR 20 2015

THE NWS STORM PREDICTION CENTER HAS ISSUED A

* TORNADO WATCH FOR PORTIONS OF 
  DISTRICT OF COLUMBIA
  DELAWARE
  MARYLAND
  SOUTHWEST NEW JERSEY
  SOUTHERN PENNSYLVANIA
  NORTHERN VIRGINIA
  EASTERN PANHANDLE OF WEST VIRGINIA
  COASTAL WATERS

* EFFECTIVE THIS MONDAY AFTERNOON AND EVENING FROM 305 PM UNTIL
  1000 PM EDT.

* PRIMARY THREATS INCLUDE...
  A COUPLE TORNADOES POSSIBLE
  SCATTERED LARGE HAIL AND ISOLATED VERY LARGE HAIL EVENTS TO 2
    INCHES IN DIAMETER POSSIBLE
  SCATTERED DAMAGING WIND GUSTS TO 70 MPH POSSIBLE

SUMMARY...THUNDERSTORMS ARE EXPECTED TO DEVELOP OVER NORTHERN VA AND
WESTERN MD THIS AFTERNOON...TRACKING ACROSS THE WATCH AREA. 
DAMAGING WINDS AND HAIL ARE THE MAIN THREATS.  HOWEVER...BACKED LOW
LEVEL WINDS NEAR A WARM FRONT MAY BE SUFFICIENT TO ENHANCE THE RISK
OF ISOLATED TORNADOES OVER NORTHERN PARTS OF THE WATCH.

THE TORNADO WATCH AREA IS APPROXIMATELY ALONG AND 90 STATUTE
MILES EAST AND WEST OF A LINE FROM 30 MILES EAST SOUTHEAST OF
CHARLOTTESVILLE VIRGINIA TO 25 MILES NORTH OF HARRISBURG
PENNSYLVANIA.  FOR A COMPLETE DEPICTION OF THE WATCH SEE THE
ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU0).

PRECAUTIONARY/PREPAREDNESS ACTIONS...

REMEMBER...A TORNADO WATCH MEANS CONDITIONS ARE FAVORABLE FOR
TORNADOES AND 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.

&&

OTHER WATCH INFORMATION...CONTINUE...WW 86...WW 87...WW 88...WW
89...

AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL
SURFACE AND ALOFT TO 2 INCHES. EXTREME TURBULENCE AND SURFACE
WIND GUSTS TO 60 KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO
500. MEAN STORM MOTION VECTOR 25030.


...HART

Tornado Watches in Pennsylvania, 2015Tornado Watches in Virginia, 2015Tornado Watches in Maryland, 2015Every tornado watch in 2015

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.