Tornado Watch 152

Issued

Apr 16, 2011, 4:41 PM EDT (20:41 UTC)

Expired

Apr 16, 2011, 10:35 PM EDT

In force

6 hr

Issued by

the Storm Prediction Center

Largest hail expected

0.5 in

Strongest gust expected

60 kt

Counties Adams County, PA, Bedford County, PA, Berks County, PA, Blair County, PA, Chester County, PA, Cumberland County, PA, Dauphin County, PA, Delaware County, PA, Franklin County, PA, Fulton County, PA, Huntingdon County, PA, Juniata County, PA, Lancaster County, PA, Lebanon County, PA, Mifflin County, PA, Perry County, PA, Schuylkill County, PA, Snyder County, PA, York County, PA

The State College radar (KCCX), 69 km from the middle of the area, began a volume at 20:41 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

30%

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 457Apr 16, 2:05 PM EDT
• Mesoscale Discussion 459Apr 16, 4:29 PM EDT
• Mesoscale Discussion 461Apr 16, 6:38 PM EDT
• Mesoscale Discussion 465Apr 16, 9:58 PM EDT

863 
WWUS20 KWNS 162041
SEL2
SPC WW 162041
DEZ000-MDZ000-NJZ000-PAZ000-CWZ000-170300-

URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 152
NWS STORM PREDICTION CENTER NORMAN OK
440 PM EDT SAT APR 16 2011

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

       DELAWARE
       EASTERN MARYLAND
       SOUTHWEST NEW JERSEY
       SOUTHERN PENNSYLVANIA
       COASTAL WATERS

EFFECTIVE THIS SATURDAY AFTERNOON AND EVENING FROM 440 PM UNTIL
1100 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 35 STATUTE
MILES NORTH AND SOUTH OF A LINE FROM 30 MILES WEST OF ALTOONA
PENNSYLVANIA TO 55 MILES EAST OF HARRISBURG PENNSYLVANIA.  FOR A
COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH OUTLINE
UPDATE (WOUS64 KWNS WOU2).

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...WW 151...

DISCUSSION...STRONG PRESSURE FALLS OCCURRING OVER ERN PA/NJ ARE
INDICATIVE OF INTENSE LOW-LEVEL WAA AND THE NEWD PROGRESSION OF
SURFACE LOW CURRENTLY ANALYZED OVER WRN VA /N OF ROA/.  WHILE
AMBIENT AIR MASS IS EXPECTED TO REMAIN ONLY MARGINALLY
UNSTABLE...THE PRESENCE OF STRONG LARGE-SCALE FORCING FOR ASCENT AND
EXTREME VERTICAL SHEAR INDICATE A RISK FOR BOWING AND/OR SUPERCELL
STRUCTURES CAPABLE OF DAMAGING WIND GUSTS AND A COUPLE TORNADOES.

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
300. MEAN STORM MOTION VECTOR 20045.


...MEAD

Tornado Watches in Pennsylvania, 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.