1. Thunderstorm - Wikipedia, The Free Encyclopedia Brief overview of thunderstorms and their life cycle. http://en.wikipedia.org/wiki/Thunderstorm

Thunderstorm From Wikipedia, the free encyclopedia Jump to: navigation search A shelf cloud associated with a heavy or severe thunderstorm over Enschede The Netherlands Look up thunderstorm in Wiktionary , the free dictionary. A thunderstorm , also called an electrical storm or lightning storm , is a form of weather characterized by the presence of lightning and its attendant thunder Contents Life cycle Cumulus stage Mature stage Dissipating stage ... edit Life cycle Airflow diagrams showing three stages of a thunderstorm life cycle. As the air begins to lift, it eventually starts to cool and condensation takes place. When the moisture condenses, heat is released which further aids in the lifting process. If enough instability is present in the atmosphere, this process will continue long enough for cumulonimbus clouds to form, which supports lightning and thunder. All thunderstorms, regardless of type, go through three stages: the cumulus stage , the mature stage , and the dissipation stage . Depending on the conditions present in the atmosphere, these three stages can take anywhere from 20 minutes to several hours to occur. edit Cumulus stage The first stage of thunderstorm is the cumulus stage, or developing stage. In this stage, masses of moisture are lifted upwards into the atmosphere. The trigger for this lift can be

2. FEMA: Thunderstorms And Lightning Contains background information and a thunderstorm factsheet. http://www.fema.gov/hazard/thunderstorm/index.shtm

Contact Us Site Map Frequently Asked Questions Search Advanced Search Home Disaster Information Plan Ahead ... After a Thunderstorm Thunderstorms and Lightning Facts About Thunderstorms Facts About Lightning How Can I Protect Myself From a Thunderstorm or Lightning? Dry thunderstorms that do not produce rain that reaches the ground are most prevalent in the western United States. Falling raindrops evaporate, but lightning can still reach the ground and can start wildfires. Facts About Thunderstorms They may occur singly, in clusters, or in lines. Some of the most severe occur when a single thunderstorm affects one location for an extended time. Thunderstorms typically produce heavy rain for a brief period, anywhere from 3 minutes to an hour. Warm, humid conditions are highly favorable for thunderstorm development. Back To Top Facts About Lightning Lightning often strikes outside of heavy rain and may occur as far as 10 miles away from any rainfall. "Heat lightning" is actually lightning from a thunderstorm too far away for thunder to be heard. However, the storm may be moving in your direction! Most lightning deaths and injuries occur when people are caught outdoors in the summer months during the afternoon and evening.

3. USAToday.com Thunderstorms Contains information on types of thunderstorms, lightning, and precipitation. http://www.usatoday.com/weather/wtsm0.htm

4. Thunderstorms Contains information on the formation of a thunderstorm, types of thunderstorms, and lightning and thunder. http://www.windows.ucar.edu/tour/link=/earth/Atmosphere/tstorm.html

A note to our users: The site will be temporarily down for server maintenance on January 26, from 6am to 6pm MDT ( 12:00 - 24:00 UTC ) Use the Time Zone Converter to find out when this will happen in your time zone. Thunderstorms Click on image for full size version ( 353K JPG Courtesy of Angie J Venturato It is late afternoon. The white puffy clouds that have been growing all day are replaced by a greenish sky. A distant rumble is heard...then another. It starts to rain . A flash of light streaks the sky, followed by a huge BOOM. Welcome to a thunderstorm. Thunderstorms are one of the most thrilling and dangerous of weather phenomena . Over 40,000 thunderstorms occur throughout the world each day Thunderstorms have several distinguishing characteristics that can cause large amounts of damage to humans and their property. Straight-line winds and tornadoes can uproot trees and demolish buildings. Hail can damage cars and crops. Heavy rains can create flash floods. Lightning can spark a forest fire or hurt you. Safety during a thunderstorm is really important.

5. Thunderstorms Lightning can occur not only in thunderstorms, but also in snowstorms, sand storms, above erupting volcanoes and from nuclear explosions. http://www.wxdude.com/page5.html

Thunderstorms Thunder and Lightning Hear a Music Clip Lyrics to Song Get the most out of these pages with the Weather Dude ... Qustions and Answers about Thunderstorms and Severe Weather Flash Facts: An estimated two thousand thunderstorms are going on in the world at any one time. The diameter of a lightning bolt is about a half-inch to an inch wide, but can be up to five inches wide. The average length of a lightning bolt from a cloud to the ground is three to four miles long. When lightning strikes a sandy beach, the intense heat turns a small portion of the sand into glass. These icicle-shaped pieces are called "fulgurites ." A flash of lightning appears to flicker because there are usually several bolts of lightning striking at almost the same time. Lightning can occur not only in thunderstorms, but also in snowstorms, sand storms, above erupting volcanoes and from nuclear explosions. Word Up: Anvil: This is what the top of a cumulonimbus cloud is called because it resembles an anvil that blacksmiths and metal workers use to hammer and bend metal. Have you ever seen tall, dark puffy clouds forming on a hot humid afternoon? These are called cumulonimbus clouds, sometimes nicknamed "thunderheads."

6. Questions And Answers About Thunderstorms: Basics Answers questions such as how thunderstorms are formed, how they re detected, and what type of damage they can do. http://www.nssl.noaa.gov/primer/tstorm/tst_basics.html

To view the answers to the Frequently Asked Questions and the vocabulary definitions you need to have Javascript enable in your browser. A SEVERE WEATHER PRIMER: Questions and Answers about THUNDERSTORMS home education severe weather primer THUNDERSTORM FAQs What is a supercell? Why are there thunderstorms? Are there winter thunderstorms? A supercell is an often dangerous convective storm with a very organized internal structure including a rotating updraft that allows it to keep going for up to several hours. Supercells are capabile of producing severe weather including high winds, large hail, and strong tornadoes. They are most frequently isolated and often develop in the warm air ahead of a squall line. A supercell also usually forms in an environment with strong vertical wind shear that causes the updraft to begin rotating. Winter thunderstorms are rare because the air is more stable – strong updrafts cannot form because the surface temperatures during the winter are colder. Thunderstorms Climatology Detecting Forecasting ... GLOSSARY Thunderstorm Basics What is a thunderstorm?

7. American Red Cross thunderstorms and Lightning the Underrated Killers, If you would like permission to use the information about thunderstorms on this page in a http://www.redcross.org/services/prepare/0,1082,0_247_,00.html

For News, Safety Tips and Disaster Updates Blackouts Chemical Emergencies Drought Earthquakes ... Winter Storms Find Your Local Red Cross Enter Zip Code Here: Or Browse Through A List of Chapters! Circle of Humanitarians Look Who's Helping ... Get Prepared Severe Thunderstorm Versión en Español (PDF File) Table of Contents Before Lightning Strikes When a Storm Approaches What To Do if Caught Outside Protecting Yourself Outside ... More Information Links Take our Lightning Quiz Thunderstorms and Lightning...the Underrated Killers , in-depth Information about thunderstorms from the National Weather Service Before Lightning Strikes... Keep an eye on the sky. Look for darkening skies, flashes of light, or increasing wind. Listen for the sound of thunder. If you can hear thunder, you are close enough to the storm to be struck by lightning. Go to safe shelter immediately. Listen to NOAA Weather Radio, commercial radio, or television for the latest weather forecasts. When a Storm Approaches... Find shelter in a building or car. Keep car windows closed and avoid convertibles. Telephone lines and metal pipes can conduct electricity. Unplug appliances. Avoid using the telephone or any electrical appliances. (Leaving electric lights on, however, does not increase the chances of your home being struck by lightning.)

8. Thunderstorms thunderstorms, which exist in cumulonimbus clouds, deserve special treatment from pilots for several reasons. Often, you may hear pilots on the radio http://www.geo.mtu.edu/department/classes/ge406/jmedward/tstorms/index.html

Thunderstorms This page contains information reguarding thunderstorms and the hidden dangers involved in them. Thunderstorms, which exist in cumulonimbus clouds, deserve special treatment from pilots for several reasons. Often, you may hear pilots on the radio referring to "towering cues to the south" or "several CBs to the west". They are talking about clouds which indicate severe weather. Three elements must be present for thunderstorm development: Warm air Moisture Unstable air mass If all three of these elements are present, it takes very little to begin the processmerely some form of uplifting. Uplifting may be caused by several sources such as a frontal passage , the sun heating the ground and causing the warm air by the ground to rise, or even wind blowing up the side of a mountain. Once this uplifting has begun, the warm moist air is carried upwards until the temperature surrounding the parcel of air drops below the dew point for that parcel of air. At that time, the moisture inside of the parcel of air will begin to condense out and form the fluffy cumulous clouds we're all familiar with seeing forming on sunny afternoons. As this moisture condenses, it releases latent heat and warms the air parcel more, causing more uplifting. Thus, the thunderstorm, which began as a typical cumulous cloud, continues to become larger and more buoyant. This stage of formation is known as the cumulous stage and is illustrated in the following picture. The cumulous stage of thunderstorm formation.

9. Ready.gov: Thunderstorms All thunderstorms produce lightning and all have the potential for danger. Those dangers can include tornadoes, strong winds, hail, wildfires and flash http://www.ready.gov/america/beinformed/thunderstorms.html

Skip to navigation Skip to content Ready America Ready Business ... Ready Kids Search: Thunderstorms Downloading and Ordering All Ready Publications Overview ... State and Local Information Here's Something To Think About... Always participate in workplace evacuation drills and consider keeping a smaller version of your emergency supply kit in your desk. Thunderstorms and Lightning In the United States lightning kills 300 people and injures 80 on average, each year. All thunderstorms produce lightning and all have the potential for danger. Those dangers can include tornadoes, strong winds, hail, wildfires and flash flooding, which is responsible for more fatalities than any other thunderstorm-related hazard. Lightning's risk to individuals and property is increased because of its unpredictability. It often strikes outside of heavy rain and may occur as far as 10 miles away from any rainfall. Most lightning deaths and injuries occur when people are caught outdoors in the summer months during the afternoon and evening. Preparing for a Thunderstorm and Lightning Familiarize yourself with the terms that are used to identify a thunderstorm hazard, including understanding the difference between a severe thunderstorm watch and a severe thunderstorm warning.

10. Thunderstorm Although every thunderstorm in Florida has the potential to cause death, injury or damage, about 10 % produce dangerous winds or hail that will likely http://www.floridadisaster.org/bpr/EMTOOLS/Severe/thunderstorms.htm

Contact Site Index FL Hazard Lookup NATURAL - Hurricane - Earthquakes - Lightning - Tornado - Rain - Flood - Cold - Drought - El Nino - Heat Wave - Wildfire - Animal - Marine - Space TECH. - Computer - Foundation - HazMat - Nuclear CIVIL - Politics - Bombs - Info. Warfare - Terrorism - Aircraft Public Business EM Community Organization ... Kids Prepare and Stay Aware! Search Home Hazards Page / Thunderstorms Florida Hazards Watch Thunderstorms What Makes a Severe Thunderstorm? Although every thunderstorm in Florida has the potential to cause death, injury or damage, about 10 % produce dangerous winds or hail that will likely exceed thresholds known to cause significant damage to well-built structures or cause bodily harm. These are known as severe thunderstorms. Severe thunderstorms produce hail the size of a dime or larger and/or winds of 58 miles per hour or greater Where Are Severe Thunderstorms Likely to Occur? On average, the interior sections of central Florida receive the most thunderstorms with nearly 100 plus days per year. However, thunderstorms are also frequent along coastal areas which average 80 to 90 days per year. Although Florida thunderstorms are generally less than 15 miles in diameter, they can grow vertically to great heights in excess of 10 miles high into the atmosphere. This stacking effect of concentrated moisture can explain why a Florida thunderstorm directly overhead could produce four or more inches of rain in less than an hour while a location a few miles away may see only a trace. Where Can You Go For Up-To-Date Info?

11. Thunderstorms Explains the difference between four different types of thunderstorms, with pictures and graphics. http://weather.cod.edu/sirvatka/ts.html

THUNDERSTORMS There are three types of thunderstorms: single-cell (or air mass) multicell cluster multicell (or squall line) supercell Photos of the Single Cell, Multi-Cell Cluster and Multi-Cell Squall Line were taken by NSSL The photo of the Supercell was taken by Howie Bluestein The photos were taken from the storm spotters guide at the University of Illinois' Daily Planet web page. Although the natural environment does not fall into three distinct categories, we break them down to help illustrate significant differences. The differences arise because of varying atmospheric profiles, especially those concerned with vertical shear, defined as the change in wind velocity (speed or direction) with height, or The air mass thunderstorm is a common and usually non-severe phenomenon that forms away from frontal systems or other synoptic-scale disturbances. They form where moist and unstable conditions exist in the atmosphere. Air mass thunderstorms are usually produced in areas of very little vertical shear. As a result, the threat for severe is small. When they do reach severe limits, the thunderstorms may produce brief high winds or hail which develop because of high instability. These storms are know as pulse severe storms. Although several storm cells can develop, each individual cell lasts about 30-60 minutes and has three stages.

12. Thunderstorms The key ingredient that defines a thunderstorm is lightning. Since lightning creates thunder, a storm with lightning is called a thunderstorm. http://www.ussartf.org/thunderstorms.htm

United States Search and Rescue Task Force Thunderstorms The key ingredient that defines a thunderstorm is lightning. Since lightning creates thunder, a storm with lightning is called a thunderstorm. Thunderstorms occur when large air masses rise quickly into the atmosphere, forming huge cumulonimbus clouds. Severe air currents inside the clouds cause water droplets and ice crystals to crash into one another continually, and the friction between these particles creates static electricity in the cloud. Over time, opposite charges build between the top and bottom of the cloud, and the bottom of the cloud and the earth. When these opposing charges become intense, a gigantic spark occurs (lightning) which jumps the gap between the cloud and the earth. The thunder accompanying lightning is the noise produced by the discharge. What is Lightning? The action of rising and descending air within a thunderstorm separates positive and negative charges. Water and ice particles also affect the distribution of electrical charge. Lightning results from the buildup and discharge of electrical energy between positively and negatively charged areas.

13. Natural Hazards.org: Investigate: Thunderstorms thunderstorms are usually small, organized parcels of warm and moist air that produce lightning and thunder. They are one of Nature s frequent ways of http://www.naturalhazards.org/investigate/tstorms/

Mammatus clouds billow beneath a supercell thunderstorm at sunset in southern Wisconsin. This page is available for sponsorship! (more information here) WHAT are thunderstorms? Thunderstorms are usually small, organized parcels of warm and moist air that produce lightning and thunder. They are one of Nature's frequent ways of balancing the amount of energy in the atmosphere - it is estimated that over 40,000 thunderstorms occur each day around the world. Although most last only 30 minutes, thunderstorms can create several dangerous phenomena: Torrential rain: rain produced by thunderstorms is usually intense, but short in duration - flash flooding is often associated with this type of precipitation. In fact, flooding is the greatest threat from thunderstorms, killing more people in the United States in an average year than tornadoes or lightning. Torrential rain can cause flooding many miles downstream of a thunderstorm's location, catching people off guard. Slope failures can also be triggered by the intense precipitation from thunderstorms in hilly and mountainous regions. Reduced visibility is common in the downdrafts of thunderstorms, where rainfall rates are the highest.

14. VAEmergency.com > Threats & Emergencies > Thunderstorms thunderstorms can occur any time of day year round, but are most common in the summer afternoons and evenings. The National Weather Service considers a http://www.vaemergency.com/threats/thunderstorm/

Skip to Content Online Services Commonwealth Sites Help ... Governor Search Virginia.gov: Home Threats Wireless VDEM Home ... Training Calendar VA Business Toolkit Citizen Corps Emergency Management Community Home Grant Information Library How can we make this site better? Let us know ... Thunderstorms Thunderstorm Basics Responding to Thunderstorms Thunderstorms can occur any time of day year round, but are most common in the summer afternoons and evenings. The National Weather Service considers a thunderstorm severe if it produces hail at least three-quarters of an inch in diameter, has winds of 58 miles per hour or higher or produces a tornado. All thunderstorms produce lightning, which can be deadly. Virginia averages 35 to 45 thunderstorm days per year. Home Jobs EM Update Contact Us ... Online VEOC Login www.VAEmergency.com: Virginia's Emergency Web site WAI Level A Compliant Choose a threat Blackouts Chemical Drought Floods Geologic Events Hazmat Incidents Heat-related Hurricanes Lightning Public Health Threats Radiological Events Terrorism Thunderstorms Tornadoes Wildfires Winter Weather Blackouts Chemical Drought Floods ... Winter Weather Subscribe to VDEM news EM Update Training News Flash News Releases Grants E-mail Alerts ... VDEM RSS Feed Related Info 2005 Lightning Safety campaign Lightning

15. What Causes Thunderstorms? thunderstorms form when an air mass becomes so unstable that it overturns (convects) violently. Unstable means that the air in the lowest layers is http://www.weatherquestions.com/What_causes_thunderstorms.htm

HOME CLOUD/PRECIP FCST MOVIE TEMPERATURE FCST MOVIE 2005 HURRICANES ... 2007 HURRICANES What causes thunderstorms? Thunderstorms form when an air mass becomes so unstable that it overturns ( convects ) violently. "Unstable" means that the air in the lowest layers is unusually warm and humid, or that the upper layers are unusually cool, or oftentimes, both . Rising near-surface air in an unstable air mass expands and cools, and finds itself still warmer than it's environment, which causes it to rise even farther. If enough water vapor is present, some of this vapor condenses into a cloud, releasing heat, which makes the air parcel even warmer, forcing it to rise yet again. In thunderstorms, this process continues to feed on water vapor in the lower atmosphere, pumping air warmed by condensation as high as 40,000 to 60,000 feet (8 to 12 miles). Thunderstorms are more common in the afternoon over land, when daytime heating of the land by the sun causes the lower part of the troposphere to become unstable. Or, some thunderstorms can form from the upper atmosphere becoming unusually cool, due to the approach of an upper air disturbance. In this case storms can form at any time of day, even when there hasn't been daytime heating of the land. One absolute requirement, however, is there has to be sufficient water vapor to feed the storm. This is the fuel for the thunderstorm. As the storm uses up this fuel, it is converted to rainfall. Eventually, the storm stabilizes the atmosphere, through using up the excess water vapor, cooling the lower troposphere, and warming the upper troposphere. A discussion of what causes lightning can be found

16. FLASH: Federal Alliance For Safe Home thunderstorms may occur singly, in clusters or in lines. Some of the most severe weather occurs when a single thunderstorm affects one location for an http://www.flash.org/activity.cfm?currentPeril=11

17. Thunderstorms & Lightning Some thunderstorms can be seen approaching, while others hit without warning. It is important to learn and recognize the danger signs and to plan ahead. http://www.pp.okstate.edu/ehs/chapters/Thunder.htm

Some thunderstorms can be seen approaching, while others hit without warning. It is important to learn and recognize the danger signs and to plan ahead. What you should do... ... a thunderstorm. BEFORE Learn the thunderstorm danger signs. Dark, towering, or threatening clouds. Distant lightning and thunder. Estimating the Distance from a Thunderstorm Because light travels much faster than sound, lightning flashes can be seen long before the resulting thunder is heard. Estimate the number of miles you are from a thunderstorm by counting the number of seconds between a flash of lightning and the next clap of thunder. Divide this number by five. Important: You are in danger from lightning if you can hear thundereven if the storm is not overhead. Have disaster supplies on hand... Flashlight with extra batteries Portable, battery-operated radio and extra batteries First aid kit and manual Emergency food and water Non-electric can opener Essential medicines Cash and credit cards Sturdy shoes Check for hazards in the yard.

18. Thunderstorms - Environment Canada This page describes thunder and precautions to take in the event of a thunder storm. http://www.mb.ec.gc.ca/air/summersevere/ae00s20.en.html

Français Contact Us Help Search ... Weatheradio Extreme Events Alberta Saskatchewan Manitoba J u s t F o r K i d s Summer Tips Weather Words Thunderstorms Summer thunderstorms are a fairly common occurrence in most areas of Canada, providing much-needed precipitation for gardens, crops, and other purposes. Unfortunately, a small percentage of summer thunderstorms intensify to the extent that they become "severe", causing damage to property and threatening lives. Environment Canada will issue a severe thunderstorm or tornado warning if heavy rain, high winds, tornadoes, hail or intense lightning are present or expected. The storm's expected motion and developments are also provided in the weather warning. If you hear a weather warning and are in the area specified, take appropriate precautions. General Precautions The following general precautions offer advice on how you can plan in advance to cope more safely with a severe thunderstorm. Choose a shelter in advance. Good places to be during severe storms are basements, storm cellars, and fall-out shelters, or underneath stairs or sturdy furniture in the centre of the house. See

19. Thunderstorms A thunderstorm is a storm with lightning and thunder. Its produced by a cumulonimbus cloud, usually producing gusty winds, heavy rain and sometimes hail. http://www.weatherwizkids.com/thunderstorm.htm

Home Hurricanes Tornadoes Winter Storms ... Site Advertising Get Your Forecast! Enter Your "City, St" or "Zipcode" What is a thunderstorm? A thunderstorm is a storm with lightning and thunder. Its produced by a cumulonimbus cloud, usually producing gusty winds, heavy rain and sometimes hail. What causes a thunderstorm? The basic ingredients used to make a thunderstorm are moisture, unstable air and lift. You need moisture to form clouds and rain. You need unstable air that is relatively warm and can rise rapidly. Finally, you need lift. This can form from fronts, sea breezes or mountains. When are thunderstorms most likely to occur? Thunderstorms can occur year-round and at all hours. But they are most likely to happen in the spring and summer months and during the afternoon and evening hours. How many thunderstorms are there every day? It is estimated that there are around 1,800 thunderstorms that occur across our planet every day. Are thunderstorms dangerous? Yes, despite their small size, all thunderstorms are dangerous. Every thunderstorm produces lightning, which kills more people each year than tornadoes.

20. Thunderstorm We have all experienced the darkening skies and sheets of rain that accompany thunderstorms. Flashes of lightning and blinding rain are cliché in horror http://cimss.ssec.wisc.edu/wxwise/class/thndstr.html

Thunderstorms thunderstorm hazards include lightning, hail, tornadoes, downbursts, torrential rains and flooding. Weather associated with thunderstorms may have a significant impact on the environment: flooding may result in severe soil erosion and lightning strikes may start large fires. A thunderstorm, which consists of a cumulonimbus cloud, form in an unstable envirnoment that has moisture at low levels. In addition, upper level divergence must exist to support the converging air at the surface. Upper level divergence acts to suck the air up from the surface. There are two basic types of thunderstorms airmass thunderstorm and the severe thunderstorm. The satellite view of a thunderstorm is demonstrated in a GOES-8 satellite 1 minute loop of a storm over Oklahoma. This loop is from the home page of Dr. Chesters at NASA Goddard. Air Mass Thunderstorm The air mass thunderstorm is common in Florida. As with all thunderstorms, it contains thunder and therefore has lightning. The air mass thunderstorm lasts approximately one hour and has a very distinctive life cycle. Cumulus Stage : Rising air, or updraft, cools and forms the cloud. The rising air is occurring in an environment that is favorable for convection. Lifting mechanism include solar heating or convergence from a sea breeze. It is not raining during this stage of the thunderstorm.

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