Tornado Watch 151

Issued

Apr 16, 2011, 1:29 PM EDT (17:29 UTC)

Expired

Apr 16, 2011, 9:00 PM EDT

In force

8 hr

Issued by

the Storm Prediction Center

Largest hail expected

0.5 in

Strongest gust expected

60 kt

The Sterling radar (KLWX), 44 km from the middle of the area, began a volume at 17:31 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

40%

One or more gusts of 65 knots or more

30%

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

70%

• Mesoscale Discussion 455Apr 16, 12:52 PM EDT
• Mesoscale Discussion 459Apr 16, 4:29 PM EDT
• Mesoscale Discussion 461Apr 16, 6:38 PM EDT
• Mesoscale Discussion 463Apr 16, 8:12 PM EDT

039 
WWUS20 KWNS 161729
SEL1
SPC WW 161729
DCZ000-MDZ000-VAZ000-WVZ000-CWZ000-170100-

URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 151
NWS STORM PREDICTION CENTER NORMAN OK
130 PM EDT SAT APR 16 2011

THE NWS STORM PREDICTION CENTER HAS ISSUED A
TORNADO WATCH FOR PORTIONS OF

       DISTRICT OF COLUMBIA
       MARYLAND
       NORTHERN VIRGINIA
       EASTERN WEST VIRGINIA
       COASTAL WATERS

EFFECTIVE THIS SATURDAY AFTERNOON AND EVENING FROM 130 PM UNTIL
900 PM EDT.

TORNADOES...HAIL TO 0.5 INCH IN DIAMETER...THUNDERSTORM WIND
GUSTS TO 70 MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE
AREAS.

THE TORNADO WATCH AREA IS APPROXIMATELY ALONG AND 80 STATUTE
MILES EAST AND WEST OF A LINE FROM 30 MILES NORTHEAST OF
MARTINSBURG WEST VIRGINIA TO 25 MILES WEST OF RICHMOND VIRGINIA.
FOR A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH
OUTLINE UPDATE (WOUS64 KWNS WOU1).

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 150...

DISCUSSION...A STRONGLY FORCED BAND OF TSTMS DEVELOPING ALONG
SYNOPTIC COLD FRONT IS EXPECTED TO PROGRESS EWD ACROSS THE WW AREA
THIS AFTERNOON INTO EVENING.  INTENSE PRESSURE FALLS OVER THE MID
ATLANTIC STATES ARE RESULTING IN THE NWD FLUX OF AN INCREASINGLY
WARM AND MOIST BOUNDARY LAYER INTO THE AREA WHICH WILL ALLOW FOR
STORMS TO BECOME PROGRESSIVELY SURFACE-BASED.  GIVEN THE VERY STRONG
WIND FIELD IN PLACE...THE POTENTIAL WILL EXIST FOR EMBEDDED BOWING
AND SUPERCELL STRUCTURES WITH A RISK FOR TORNADOES AND DAMAGING WIND
GUSTS.

AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL
SURFACE AND ALOFT TO 0.5 INCH. EXTREME TURBULENCE AND SURFACE
WIND GUSTS TO 60 KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO
350. MEAN STORM MOTION VECTOR 21050.


...MEAD

Tornado Watches in Virginia, 2011Tornado Watches in Maryland, 2011Tornado Watches in West Virginia, 2011Every tornado watch in 2011

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.