Severe Thunderstorm Watch 478

Issued

Jul 7, 2012, 2:16 PM EDT (18:16 UTC)

Expired

Jul 7, 2012, 7:00 PM EDT

In force

5 hr

Issued by

the Storm Prediction Center

Largest hail expected

2 in

Strongest gust expected

60 kt

Two or more tornadoes

10%

One or more EF2 to EF5 tornadoes

2%

Ten or more severe wind reports

70%

One or more gusts of 65 knots or more

10%

Ten or more severe hail reports

30%

One or more hailstones of 2 inches or more

10%

Six or more combined severe hail and wind reports

80%

• Mesoscale Discussion 1424Jul 7, 11:19 AM EDT
• Mesoscale Discussion 1426Jul 7, 1:48 PM EDT
• Mesoscale Discussion 1430Jul 7, 3:57 PM EDT
• Mesoscale Discussion 1431Jul 7, 5:43 PM EDT

195 
WWUS20 KWNS 071816
SEL8
SPC WW 071816
OHZ000-PAZ000-WVZ000-072300-

URGENT - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WATCH NUMBER 478
NWS STORM PREDICTION CENTER NORMAN OK
215 PM EDT SAT JUL 7 2012

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

       CENTRAL AND EASTERN OHIO
       WESTERN AND CENTRAL PENNSYLVANIA
       NORTHERN WEST VIRGINIA PANHANDLE

EFFECTIVE THIS SATURDAY AFTERNOON AND EVENING FROM 215 PM UNTIL
700 PM EDT.

HAIL TO 2 INCHES IN DIAMETER...THUNDERSTORM WIND GUSTS TO 70
MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE AREAS.

THE SEVERE THUNDERSTORM WATCH AREA IS APPROXIMATELY ALONG AND 55
STATUTE MILES NORTH AND SOUTH OF A LINE FROM 45 MILES NORTH
NORTHWEST OF ZANESVILLE OHIO TO 40 MILES NORTH NORTHEAST OF STATE
COLLEGE PENNSYLVANIA.  FOR A COMPLETE DEPICTION OF THE WATCH SEE
THE ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU8).

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 477...

DISCUSSION...NEW STORMS HAVE DEVELOPED OVER EXTREME SWRN NY AND NERN
OH IN ADVANCE OF A COLD FRONT MOVING SEWD ACROSS THE LOWER GREAT
LAKES.  THE AIR MASS IS HOT/MOIST AND VERY UNSTABLE WITH MLCAPE OF
2500-3500 J/KG.  AREA IS ALONG THE SRN EDGE OF STRONGER WNWLY FLOW
ALOFT...PROVIDING SUFFICIENT DEEP LAYER SHEAR FOR ORGANIZED
MULTICELL STORMS TO DEVELOP.  DAMAGING WIND GUSTS AND LARGE HAIL
WILL BE POSSIBLE WITH STRONGER STORMS.

AVIATION...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 550. MEAN STORM
MOTION VECTOR 28025.


...WEISS

Severe Thunderstorm Watches in Pennsylvania, 2012Severe Thunderstorm Watches in Ohio, 2012Severe Thunderstorm Watches in West Virginia, 2012Every severe thunderstorm watch in 2012

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.