CTZ001-013-MAZ001-025-NYZ032-033-038>043-047>054-058>061-063>066-
082>084-VTZ013>015-271200-

PUBLIC INFORMATION STATEMENT
NATIONAL WEATHER SERVICE ALBANY NY
800 AM EDT TUE JUN 26 2012

...LIGHTNING SAFETY AWARENESS WEEK CONTINUES...

TODAY WE REVIEW THE SCIENCE OF LIGHTNING. 

AT ANY GIVEN MOMENT...THERE ARE 1,800 THUNDERSTORMS IN PROGRESS 
SOMEWHERE ON THE EARTH. THIS AMOUNTS TO 16 MILLION STORMS EACH 
YEAR. BE A FORCE OF NATURE AND IDENTIFY YOUR SAFE PLACE, A 
SUBSTANTIAL BUILDING OR HARD TOPPED VEHICLE, BEFORE A 
THUNDERSTORM STRIKES. 

A THUNDERSTORM FORMS IN AIR THAT HAS THREE COMPONENTS. 
MOISTURE...INSTABILITY AND SOMETHING SUCH AS A COLD FRONT TO 
CAUSE THE AIR TO RISE. CONTINUED RISING MOTIONS WITHIN THE STORM 
MAY BUILD THE CLOUD TO A HEIGHT OF 35000 TO 60000 FEET. 
TEMPERATURES HIGHER IN THE ATMOSPHERE ARE COLDER. ICE FORMS IN 
THE HIGHER PARTS OF THE CLOUD. 

ICE IN A CLOUD SEEMS TO BE A KEY ELEMENT IN THE DEVELOPMENT OF 
LIGHTNING. IN A STORM...THE ICE PARTICLES VARY IN SIZE FROM 
SMALL ICE CRYSTALS TO LARGER HAILSTONES...BUT IN THE RISING 
AND SINKING MOTIONS WITHIN THE STORM THERE ARE MANY COLLISIONS 
BETWEEN THE PARTICLES. THIS CAUSES A SEPARATION OF 
ELECTRICAL CHARGES. POSITIVELY CHARGED ICE CRYSTALS RISE TO THE 
TOP OF THE THUNDERSTORM...AND NEGATIVELY CHARGED ICE PARTICLES 
AND HAILSTONES DROP TO THE MIDDLE AND LOWER PARTS OF THE STORM.

A MOVING THUNDERSTORM GATHERS ANOTHER POOL OF POSITIVELY CHARGED 
PARTICLES ALONG THE GROUND THAT TRAVEL WITH THE STORM. AS THE 
DIFFERENCES IN CHARGES CONTINUE TO INCREASE...POSITIVELY CHARGED 
PARTICLES RISE UP TALLER OBJECTS SUCH AS TREES...HOUSES...AND 
TELEPHONE POLES. HAVE YOU EVER BEEN UNDER A STORM AND HAD YOUR 
HAIR STAND UP. YES...THE PARTICLES ALSO CAN MOVE UP YOU. THIS IS 
ONE OF NATURES WARNING SIGNS THAT SAYS YOU ARE IN THE WRONG 
PLACE...AND YOU MAY BE A LIGHTNING TARGET. 

THE NEGATIVELY CHARGED AREA IN THE STORM WILL SEND OUT A CHARGE 
TOWARD THE GROUND CALLED A STEPPED LEADER. IT IS INVISIBLE TO THE 
HUMAN EYE...AND MOVES IN STEPS IN LESS THAN A SECOND TOWARD THE 
GROUND. WHEN IT GETS CLOSE TO THE GROUND...IT IS ATTRACTED BY ALL 
THESE POSITIVELY CHARGED OBJECTS...AND A CHANNEL DEVELOPS. YOU 
SEE THE ELECTRICAL TRANSFER IN THIS CHANNEL AS LIGHTNING. THERE 
MAY BE SEVERAL RETURN STROKES OF ELECTRICITY WITHIN THE 
ESTABLISHED CHANNEL THAT YOU WILL SEE AS FLICKERING LIGHTNING. 

EACH SPARK OF LIGHTNING CAN REACH OVER FIVE MILES IN LENGTH... 
SOAR TO TEMPERATURES OF APPROXIMATELY 50,000 DEGREES 
FAHRENHEIT...AND CONTAIN 100 MILLION ELECTRICAL VOLTS. THE RAPID 
EXPANSION OF HEATED AIR CAUSES THE THUNDER. SINCE LIGHT TRAVELS 
FASTER THAN SOUND IN THE ATMOSPHERE...THE SOUND WILL BE HEARD 
AFTER THE LIGHTNING. IF YOU SEE LIGHTNING AND HEAR THUNDER AT THE 
SAME TIME...THAT LIGHTNING IS IN YOUR NEIGHBORHOOD. 

REMEMBER...IF YOU CAN HEAR THUNDER...YOU CAN BE STRUCK BY 
LIGHTNING. IF THE THUNDER ROARS...GO INDOORS.

TOMMORROW WE TURN OUR ATTENTION TO OUTDOOR LIGHTNING SAFETY.  

FOR MORE INFORMATION ON LIGHTNING SAFETY AWARENESS WEEK...GO TO 
OUR WEB SITE. WWW.WEATHER.GOV AND THEN CLICK ON EASTERN NEW YORK 
OR WESTERN NEW ENGLAND. FINALLY...SELECT OUR LIGHTNING SAFETY 
AWARENESS WEEK LINK.

$$
DIRIENZO