...PENNSYLVANIA WEATHER EMERGENCY PREPAREDNESS WEEK...

THIS IS THE SECOND OF A FIVE PART SERIES ON SEVERE WEATHER SAFETY 
WHICH WILL RUN EACH DAY DURING PENNSYLVANIA/S WEATHER EMERGENCY 
PREPAREDNESS WEEK.

...SEVERE THUNDERSTORMS...

WHEN SOMEONE SAYS THUNDERSTORM, THE MOST COMMON THOUGHTS ARE OF 
LIGHTNING AND THUNDER. THE SOUND OF THUNDER IS CAUSED BY 
LIGHTNING...THUS IT IS IMPOSSIBLE TO HAVE ONE WITHOUT THE OTHER. THE 
CHANNEL OF AIR THROUGH WHICH LIGHTNING TRAVELS IS HEATED TO A 
TEMPERATURE OF AROUND 50,000 DEGREES FAHRENHEIT...CAUSING THE AIR TO 
EXPAND RAPIDLY. THIS RAPID EXPANSION OF AIR IS WHAT PRODUCES THE 
SOUND OF THUNDER. IF YOU SEE LIGHTNING...YOU WILL HEAR THUNDER AS 
LONG AS YOU ARE NOT TOO FAR AWAY. HENCE...THERE IS NO SUCH THING AS 
HEAT LIGHTNING...THAT IS, LIGHTNING WHICH PRODUCES NO THUNDER. YOU 
ARE JUST TOO FAR AWAY TO HEAR THE SOUND. SINCE LIGHT TRAVELS FASTER 
THAN SOUND...YOU WILL OFTEN SEE LIGHTNING FIRST...THEN HEAR THUNDER 
A FEW SECONDS LATER.

A SEVERE THUNDERSTORM IS ANY THUNDERSTORM WHICH PRODUCES WIND GUSTS 
OF 58 MPH OR HIGHER...AND / OR HAIL THREE-QUARTERS OF AN INCH IN 
DIAMETER OR GREATER (THE SIZE OF A PENNY). WIND SPEEDS OF 58 MPH OR 
HIGHER CAN PRODUCE TREMENDOUS DAMAGE WHICH CAN BE MISINTERPRETED AS 
TORNADIC IN NATURE. THE NATIONAL WEATHER SERVICE DOES NOT USE 
LIGHTNING TO QUALIFY THE SEVERITY OF A THUNDERSTORM.

WHEN ATMOSPHERIC CONDITIONS APPEAR CONDUCIVE FOR THE FORMATION OF 
SEVERE THUNDERSTORMS...THE NATIONAL WEATHER SERVICE WILL ISSUE A 
SEVERE THUNDERSTORM WATCH. SUCH A WATCH CAN COVER A DOZEN OR MORE 
COUNTIES...AND CAN BE IN EFFECT FOR SEVERAL HOURS AT A TIME. A 
SEVERE THUNDERSTORM WATCH MEANS CONDITIONS ARE FAVORABLE FOR THE 
DEVELOPMENT OF STRONG WINDS AND / OR LARGE HAIL. A SEVERE 
THUNDERSTORM WATCH MEANS SEVERE THUNDERSTORMS COULD DEVELOP, BUT 
THEY ARE NOT A CERTAINTY.

IF A SEVERE THUNDERSTORM WATCH IS ISSUED...GO ABOUT YOUR NORMAL 
ACTIVITIES...BUT WATCH THE SKY AROUND YOU FOR DEVELOPING STORMS. 
PERIODICALLY CHECK NOAA WEATHER RADIO...OR TV AND RADIO STATIONS FOR 
UPDATES AND POSSIBLE WARNINGS. KNOW WHICH COUNTY YOU LIVE IN AND 
WHICH ONES SURROUND YOUR COMMUNITY. IF YOU ARE ON VACATION...OR 
DRIVING THROUGH AN UNFAMILIAR AREA...ATTEMPT TO LOCATE THE NAME OF 
THE COUNTY YOU ARE IN. FIND OUT WHERE YOU ARE IN RELATION TO OTHER 
TOWNS OR CITIES. PLAN HOW TO GET TO A SAFE PLACE QUICKLY IF A 
WARNING IS ISSUED FOR YOUR AREA...OR IF SEVERE WEATHER IS OBSERVED.

THE NATIONAL WEATHER SERVICE ISSUES A SEVERE THUNDERSTORM WARNING 
WHEN DOPPLER RADAR...OR REAL-TIME OBSERVATIONS FROM EMERGENCY 
MANAGEMENT OFFICIALS OR SKYWARN SEVERE WEATHER SPOTTERS...INDICATE A 
SEVERE THUNDERSTORM IS IN PROGRESS OR ABOUT TO OCCUR. WARNINGS ARE 
STORM-BASED...WHICH MEANS THE WARNED AREA IS ESSENTIALLY A OUTLINE 
DRAWN ON A MAP THAT DELINEATES THE MAJOR THREAT REGION REGARDLESS OF 
GEOPOLITICAL BOUNDARIES. THIS MEANS THAT AREAS OF SEVERAL DIFFERENT 
COUNTIES CAN BE CONTAINED IN ONE WARNING. THE TYPICAL SEVERE 
THUNDERSTORM WARNING IS USUALLY VALID FOR ONE HOUR OR LESS. A 
SEVERE THUNDERSTORM WARNING MEANS A SEVERE THUNDERSTORM IS ABOUT TO 
MOVE THROUGH YOUR COUNTY. TAKE QUICK ACTION TO PROTECT LIVES AND 
PROPERTY.

WHEN A SEVERE THUNDERSTORM WARNING IS ISSUED...GET INSIDE YOUR 
HOME...A STRONG BUILDING...OR IN YOUR CAR. IF THERE IS NO BUILDING 
NEARBY...YOUR BEST PROTECTION IS A DITCH...BUT BE CAREFUL OF RISING 
WATER. BOATERS SHOULD HEAD TO SHORE IMMEDIATELY...AND GOLFERS SHOULD 
GET OFF THE COURSE IMMEDIATELY. STAY AWAY FROM WINDOWS AND DOORS. DO 
NOT USE ELECTRICAL APPLIANCES AND MAKE SURE SENSITIVE ELECTRONIC 
EQUIPMENT IS SURGE PROTECTED. DO NOT USE CORDED TELEPHONES. IF YOU 
ARE DRIVING...PULL OVER TO THE SIDE OF THE ROAD UNTIL THE STORM 
PASSES. HEAVY RAIN WITH ANY THUNDERSTORM CAN FLOOD ROADS 
QUICKLY...SO NEVER TRY TO DRIVE THROUGH AN AREA WHERE WATER COVERS 
THE ROAD.

DESPITE THE FACT THAT THE NATIONAL WEATHER SERVICE DOES NOT USE 
LIGHTNING TO JUDGE THE SEVERITY OF A STORM...IT IS ONE OF THE MANY 
DANGERS ASSOCIATED WITH THUNDERSTORMS. ON AUGUST 17TH 
2003...LIGHTNING STRUCK THE STEEPLE OF SAINT MARY'S CHURCH IN PERTH 
AMBOY AND TOPPLED A LARGE CHUNK OF THE PILLAR THROUGH THE ROOF AND 
DESTROYED PEWS AND THE CHURCH'S PIPE ORGAN. THE LIGHTNING BOLT 
TRAVELED FROM THE STEEPLE THROUGH THE ROOF AND EXITED A STAINED GLASS 
WINDOW WHICH MELTED. A FIVE FOOT LONG 1200 POUND CONCRETE PIECE OF 
THE STEEPLE CRASHED THROUGH THE ROOF AND LANDED ON THE CHOIR LOFT 
AND SMASHED A 40-YEAR-OLD ORGAN. A SECOND CHUNK PLUNGED THROUGH THE 
ROOF...THE GROUND FLOOR...AND INTO THE BASEMENT WHERE IT DAMAGED 
SEVERAL PEWS. 

FOR ADDITIONAL INFORMATION ON SEVERE THUNDERSTORMS...OR WEATHER IN 
GENERAL...PLEASE VISIT THE NWS MOUNT HOLLY NJ WEBSITE AT:
WEATHER.GOV/PHILADELPHIA  (ALL IN LOWER CASE).

 
$$