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June 13, 2011

If you hear thunder, you can be struck by lightning

Terrible to read this morning about the Pasadena man who was struck by lightning just before 6 p.m. Sunday on the fishing pier at Fort Smallwood Park. Elmer Coreas, 29, was listed in critical condition today the at Maryland Shock-Trauma Center in Baltimore. First responders found him in Lightningcardiac arrest.

We hope for his recovery, and that his experience will awaken others to the dangers of staying out in the open when thunderstorms threaten.

An average of 58 people are killed each year by lightning in the U.S. Hundreds more suffer permanent injuries. The National Weather Service says these can include "a variety of long-term, debilitating symptoms, including memory loss, attention deficits, sleep disorders, chronic pain, numbness, dizziness, stiffness in joints, irritability, fatigue, weakness, muscle spasms, depression, and more."

The most important thing to remember about lightning is this: The 50,000-degree Fahrenheit lightning bolt that triggers the thunderclap can travel 10 miles. And the sound of that thunder can be heard 10 miles away from the strike. So if you can hear thunder, you can be struck by lightning from that storm. Take shelter. 

Substantial buildings and hard-topped cars will work. Standing under a tree just makes you a target, along with the tree. And standing out on a pier, the tallest thing out there, is not a good plan, either.

(SUN PHOTO: Gene Sweeney, Jr., June 9, 2011)

Posted by Frank Roylance at 11:41 AM | | Comments (1)
Categories: Lightning
        

July 15, 2010

Weather cripples local NOAA Weather Radio

Violent weather has muted the robotic voices of NOAA's Weather Radio in the Baltimore area.

NOAA Weather RadioThe Pikesville antenna that broadcasts the weather forecasts, and the all-important weather watches and warnings for the region was struck by lightning during the storm late Monday or early Tuesday.

The bolt knocked out full-power broadcasts at 162.4 Megahertz, reducing the signal to a poor-quality 500 watts. The broadcasts are punctuated by a series of beeps and little or no content from the synthetic announcers: sweet and sultry Donna, next-door neighbor Tom, and the older, and vaguely Scandanavian Paul.

The transmitter's range during repairs will be limited to no more than 5 or 10 miles. I can hear nothing in our downtown Baltimore office. Repairs are expected to take as long as two weeks, the National Weather Service said.

The good news is that the same products are available as MP3 files and RSS feeds here: http://www.erh.noaa.gov/lwx/podcasts/

(SUN PHOTO: Frank Roylance)

Posted by Frank Roylance at 10:12 AM | | Comments (3)
Categories: Lightning
        

June 23, 2009

Lightning lore, and a warning

lightning Baltimore

Although we seem to have passed through the biggest barrage of thunderstorms of this spring storm season, with notably sunnier weather ahead, there are always risks of thunder and lightning in Maryland in the summertime. So, here are some lightning facts to know and use, courtesy of the National Weather Service in observance of Lightning Safety Awareness Week:

What are thunder and lightning, and how are they produced? 

BY DEFINITION, ALL THUNDERSTORMS CONTAIN LIGHTNING.  LIGHTNING IS A
GIANT SPARK OF ELECTRICITY THAT OCCURS WITHIN THE ATMOSPHERE OR
BETWEEN THE ATMOSPHERE AND THE GROUND.  AS LIGHTNING PASSES THROUGH
THE AIR, IT HEATS THE AIR RAPIDLY TO A TEMPERATURE OF ABOUT 50,000
DEGREES FAHRENHEIT, ABOUT 5 TIMES HOTTER THAN THE SURFACE OF THE
SUN. DURING A LIGHTNING DISCHARGE, THE SUDDEN HEATING OF THE AIR
CAUSES IT TO EXPAND RAPIDLY.  AFTER THE DISCHARGE, THE AIR CONTRACTS
QUICKLY AS IT COOLS BACK TO A NORMAL TEMPERATURE.  THIS RAPID
EXPANSION AND CONTRACTION OF THE AIR CAUSES A SHOCK WAVE THAT WE
HEAR AS THUNDER (THIS SHOCK WAVE CAN DAMAGE WALLS AND BREAK GLASS).

So how is that giant electrical spark created?

AS A THUNDERSTORM CLOUD GROWS, PRECIPITATION FORMS WITHIN THE CLOUD
WITH MOSTLY SMALL ICE CRYSTALS IN THE UPPER LEVELS OF THE CLOUD, A
MIXTURE OF SMALL ICE CRYSTALS AND SMALL HAIL (GRAUPEL) IN THE MIDDLE
LEVELS OF THE CLOUD, AND A MIXTURE OF RAIN AND MELTING HAIL IN THE
LOWER LEVELS OF THE CLOUD.  DUE TO AIR MOVEMENTS AND COLLISIONS
BETWEEN THE PRECIPITATION PARTICLES NEAR THE MIDDLE OF THE CLOUD,
THE VARIOUS PRECIPITATION PARTICLES BECOME CHARGED.  THE LIGHTER ICE
CRYSTALS BECOME POSITIVELY CHARGED AND ARE CARRIED UPWARD INTO THE
UPPER PART OF THE STORM BY THE UPDRAFT.  THE HEAVIER HAIL BECOMES
NEGATIVELY CHARGED IS SUSPENDED BY THE UPDRAFT OR FALLS TOWARD THE
LOWER PART OF THE STORM.  THE END RESULT IS THAT THE TOP OF THE
CLOUD BECOMES POSITIVELY CHARGED AND THE MIDDLE AND LOWER PART OF
lightning BaltimoreTHE STORM BECOMES NEGATIVELY CHARGED.

NORMALLY, THE EARTH`S SURFACE HAS A SLIGHT NEGATIVE CHARGE;
HOWEVER, AS THE NEGATIVE CHARGES BUILD UP IN THE LOWER AND MIDDLE
PART OF THE STORM, THE GROUND BENEATH THE BASE OF THE CLOUD AND
IN THE AREA IMMEDIATELY SURROUNDING THE CLOUD BECOMES POSITIVELY
CHARGED.  AS THE CLOUD MOVES, THESE INDUCED POSITIVE CHARGES ON
THE GROUND FOLLOW THE CLOUD LIKE A SHADOW.  FARTHER AWAY FROM THE
CLOUD BASE, BUT UNDER THE POSITIVELY CHARGED ANVIL, THE NEGATIVE
CHARGE MAY BE FURTHER INDUCED.

IN THE INITIAL STAGES OF DEVELOPMENT, AIR ACTS AS AN INSULATOR
BETWEEN THE POSITIVE AND NEGATIVE CHARGES.  HOWEVER, WHEN THE
ELECTRICAL POTENTIAL BETWEEN THE POSITIVE AND NEGATIVE CHARGES
BECOMES TOO GREAT, THE INSULATING CAPACITY OF THE AIR BREAKS DOWN
AND THERE IS A DISCHARGE
OF ELECTRICITY THAT WE KNOW AS
LIGHTNING.

(SUN PHOTOS by Karl Merton Ferron 2004)

Continue reading "Lightning lore, and a warning" »

Posted by Frank Roylance at 2:31 PM | | Comments (1)
Categories: Lightning
        

July 1, 2005

A good thing

A reader from Owings Mills asks if her lightning rods are "a good thing."
The Maryland State House has used them for over two hundred years.
There have been many reports of vibrations from lightning strikes, which may explain the "ping" you hear from your chandelier.
- Jean Packard, filling in today for the vacationing Weather Blog editor

Posted by Admin at 2:36 PM | | Comments (0)
Categories: Lightning
        
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This site is the Maryland Weather archive. The current Maryland Weather blog can be found here.
Frank Roylance is a reporter for The Baltimore Sun. He came to Baltimore from New Bedford, Mass. in 1980 to join the old Evening Sun. He moved to the morning Sun when the papers merged in 1992, and has spent most of his time since covering science, including astronomy and the weather. One of The Baltimore Sun's first online Web logs, the Weather Blog debuted in October 2004. In June 2006 Frank also began writing comments on local weather and stargazing for The Baltimore Sun's print Weather Page. Frank also answers readers’ weather queries for the newspaper and the blog. Frank Roylance retired in October 2011. Maryland Weather is now being updated by members of The Baltimore Sun staff
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