81. Met Office: Education - Thunderstorms Leaflet thunderstorms. Cumulonimbus clouds. Most thunderstorms are associatedwith towering clouds known as cumulonimbus. These clouds http://www.met-office.gov.uk/education/curriculum/leaflets/thunderstorms.html

Home Education CLC Thunderstorms leaflet Weather data CLC TTC Education resources ... Webcams Thunderstorms Cumulonimbus clouds Most thunderstorms are associated with towering clouds known as cumulonimbus. These clouds normally form on warm, sunny days, although they are sometimes found on a cold front if conditions are right for their formation. Moist air near the Earth's surface is warmed by the sun, and as the air becomes warmer it starts to rise. As it rises it cools, and, if cooled sufficiently, cumulus clouds form at the condensation level. These small, white puffy clouds grow larger and larger as more warm air rises from the ground. If the cloud gets large enough, the top may penetrate the stratosphere, where the air is cooler. Strong winds in the stratosphere blow the top of the cloud downwind, and this gives the top of the cloud an anvil shape. How cumulonimbus clouds form Not all cumulonimbus clouds bring thunderstorms; some just bring heavy showers or hail. On average, an individual cumulonimbus cloud takes only one hour to take shape, grow and dissipate. It produces less than 30 minutes of thunder and lightning. If a thunderstorm lasts longer than this, it is probably because there is more than one cumulonimbus present.

82. Thunderstorms thunderstorms. This page contains information reguarding thunderstormsand the hidden dangers involved in them. thunderstorms, which http://www.geo.mtu.edu/department/classes/ge406/jmedward/tstorms/

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.

83. Science Fair Project Idea - Thunderstorms thunderstorms. thunderstorms can occur anywhere in the world and at anytime of the day. All thunderstorms produce lightning and thunder. http://parentingteens.about.com/library/sp/blscpro27.htm

zfp=-1 About Parenting of Adolescents Search in this topic on About on the Web in Products Web Hosting Parenting of Adolescents with Denise Witmer Your Guide to one of hundreds of sites Home Articles Forums ... Help zmhp('style="color:#fff"') Subjects ESSENTIALS A-Z Site Index First Time Here? College Information ... All articles on this topic Stay up-to-date! Subscribe to our newsletter. Advertising Free Credit Report Free Psychics Advertisement Science Fair Project Ideas The Five Types of Science Fair Projects Top 4 Science Fair Project Books Thunderstorms Thunderstorms can occur anywhere in the world and at any time of the day. All thunderstorms produce lightning and thunder. Some have the potential to produce damaging straight-line winds, large hail, heavy rain, flooding and tornadoes. Ideas: Explain how thunderstorms form. How does atmospheric pressure change in and around thunderstorms? Study pictures. Show differences in different storms. Explain how thunderstorms are tracked. Links: All About Thunderstorms Doppler Radar Storm Prediction Center What is a Thunderstorm? ... Email this page! Sponsored Links The Answer for Acne! - Proactiv® Solution

84. ScienceDaily News Release: Summer Thunderstorms May Become More Predictable Meteorologists have long known that summer thunderstorms and heavy rains are difficultto predict. 200206-27. Summer thunderstorms May Become More Predictable. http://www.sciencedaily.com/releases/2002/06/020627002855.htm

Search Our Archives Keywords: Order by: date relevance More options Get ad-free access with email updates sign up or log in Text size: A A A Welcome Home page About this site Awards, reviews News Summaries Headlines Topics Shop Our stuff Browse books Magazines Software Contribute Register free Post release Edit profile Review hits Advertise Media kit Traffic stats Contact us Previous Story ... Related Stories Next Story Source: National Center For Atmospheric Research (NCAR) Date: Summer Thunderstorms May Become More Predictable BOULDER Meteorologists have long known that summer thunderstorms and heavy rains are difficult to predict. They pop up quickly and disappear within a few short hours. But after looking at large numbers of radar images over four years, scientists at the National Center for Atmospheric Research (NCAR) have discovered a systematic pattern of rainfall across the continent, day after day. That knowledge should make the rainiest summer thunderstorms more predictable. The analysis of 50,000 summertime radar images showed that the movement of blocks of enhanced rainfall from west to east, from the Rockies toward the Appalachians, is an identifiable pattern, even when traditional weather maps show none of the typical weather patterns, such as fronts or low pressure systems. These eastward-moving blocks of enhanced thunderstorm activity still have individual storms popping up quickly and disappearing in a few hours, but it appears that the older storms give birth to new storms as the activity moves across the country. Thus, there is a much greater chance that a particular location will feel the effects of a thunderstorm when one of the activity areas is passing by, rather than either before or after it.

85. A.P.P., Thunderstorms - Don't Flirt ...Skirt'Em thunderstorms Don't Flirt Skirt'Em. To refresh and update the pilot's knowledgeof thunderstorms and associated weather hazards, we offer the following http://www.cyberair.com/tower/faa/app/p8740-12/0978-12.html

Accident Prevention Program Thunderstorms - Don't Flirt ...Skirt'Em Thunderstorm Pilot's Beware! Within the route you intend to fly may lie a summer hazard in wait for the unwarythe Thunderstorm. The thunderstorm, nature's uncontrolled "heat engine"often encompasses some of the worst weather hazards known to flight. To refresh and update the pilot's knowledge of thunderstorms and associated weather hazards, we offer the following: The basic requirements for formation of a thunderstorm are: Unstable air An initial updraft High moisture content of the air Why, you may ask, with these same conditions present, do we have fair weather cumulus clouds one day and thunderstorms rampant the next? There is no simple answer, however, it is known that latent heat released by condensation of existing water vapor may increase the buoyancy of a rising air column until that rising air column becomes self-sustaining. The Updraft then becomes the "burner chamber," drawing fuel from below until its fuel source is exhausted or an intermediate layer of dry stable air is encountered. The by-products of this uncontrolled "heat engine" are clouds and precipitation and sometimes vertical currents strong enough to literally disintegrate the ordinary light aircraft. The general aviation pilot must contend with thunderstorms of varying intensities in virtually all parts of the country and should be aware that all thunderstorm cells progress through three distinct stages which are more commonly called the lifecycle. These stages are:

86. Earth Observatory Glossary The scattered thunderstorms that develop in the summer are called airmass thunderstormsbecause they form in warm, maritime tropical air masses away from http://earthobservatory.nasa.gov:81/Library/glossary.php3?xref=thunderstorm

87. Thunderstorms Biometeorology 2000 thunderstorms, thunderstorms. When vertical motion islarge Where thunderstorms Occur. The greatest frequency of thunderstorms http://psb.usu.edu/psbdept/faculty/lh/bmet2000/tstorms.html

Biometeorology 2000 Thunderstorms Thunderstorms When vertical motion is large and adequate moisture is present, cumulonimbus clouds can produce lightning and thunder, and are called thunderstorms. There are several conditions that are associated with thunderstorm formation. Generally speaking we can divide these into two types of conditions. When there is a moist and unstable air mass, surface heating will produce regions of strong convection and vertical motions. These can result in isolated thunderstorm development, and are called air mass thunderstorms When fronts cause rising motion due to the collision of differing air masses, this can also create conditions for thunderstorms. These are called frontal thunderstorms , and are generally organized in structure. Lightning In order to address lightning, we must first consider the electrical charges that can be produced in clouds. Lightning is simply the flow of electrical current. It can occur within clouds, from cloud to cloud, or from cloud to ground. The latter is the least common, though it is generally what concerns us the most. First we consider charges and their separation in clouds. There is still a good deal of mystery about this subject. Here we will briefly discuss the most popular theory explaining the formation of electrical charges in clouds. Note that when supercooled water droplets collide, they freeze to form soft ice. This is called graupel. When ice crystals collide with graupel, the interaction induces the formation of electrical charges on each. The ice crystals come away from the encounter with a positive charge, while the graupel acquires a negative charge.

88. Arctic Thunderstorms, Alaska Science Forum August 11, 1979. Arctic thunderstorms Article 325. He suggested that thunderstormswould never be observed out in the icepack area more than 100 km from shore. http://www.gi.alaska.edu/ScienceForum/ASF3/325.html

Alaska Science Forum August 11, 1979 Arctic Thunderstorms Article #325 by T. Neil Davis This column is provided as a public service by the Geophysical Institute, University of Alaska Fairbanks, in cooperation with the UAF research community. T. Neil Davis is a seismologist at the institute. The history of thunderstorms observed in the high arctic reads like that of great auroras at low latitudeit dates back many years, but the number of events is not large. Part of the historical sparseness of observed thunderstorms in the Arctic Ocean and on surrounding shores is due simply to the lack of people to observe the thunderstorms. But mainly, thunderstorms are rare in arctic regions because the conditions necessary for formation of the tall clouds are lacking. A warm earth surface, irregular terrain and plenty of moisture in the middle atmosphere contribute to the formation of strong updrafts and the associated condensation of moisture at high altitudes involved in the development of thunderstorms. Looking into thunderstorm history, Mr. Arne Hanson of the Naval Arctic Research Laboratory at Barrow, Alaska, has uncovered an observation of an arctic thunderstorm made in 1580. A manuscript Hanson has prepared contains a quotation written aboard a ship sailing the Kara Sea, north of Siberia: "... the wince with a showre and thunder came to the Southwest and then wee ranne East Northeast."

89. Formation Of Thunderstorms thunderstorms In its earliest stages, tornadoes are said to stem fromthunderstorms. thunderstorms are formed within three distinct http://www2.sunysuffolk.edu/mandias/honors/student/tornado/thunderstorms.htm

Thunderstorms In its earliest stages, tornadoes are said to stem from thunderstorms . Thunderstorms are formed within three distinct stages, the first being the cumulus-stage . Certain atmospheric conditions which are present during the thunderstorm, such as moisture in the unstable air and some sort of lifting force, creates atmospheric instability. Unstable air, which is warm and moist, rises when a lifting mechanism is present. Surface heating, which acts as the primary lifting force, heats the air near the ground. The air, in turn, becomes buoyant and begins to rise, otherwise known as an updraft . These updrafts, warm, moist swells of rising air, eventually begin to cool. As this occurs the air begins to condense into a cumulus cloud . The interactions between the rising and cooling air result in the development of a positive feedback mechanism. As the warm air within the cloud continues to rise, it eventually cools and condenses. The condensation releases heat into the cloud, warming the air. This, in turn, causes it to rise adiabatically. The process continues and works to form a towering cumulus cloud. During the mature-stage , the second stage in thunderstorm development, the condensed solid and liquid water, within the upper-levels of the cloud, begins to fall, causing a downdraft . The velocity of the downdraft is strengthened by further evaporational cooling and frictional drag. Frictional drag occurs when the rain or snow drags down the surrounding colder air, which in turn increases the velocity of the downdraft. As the mature-stage thunderstorm develops, the cumulus cloud continues to increase in size, height and width. The resulting

90. Weather Variety - Annual Days With Thunderstorms Days With thunderstorms are days where a thunderstorm is close enoughfor thunder to be heard. Top 50 Cities RANK 1 2 3 4 5 6 6 http://www.weatherpages.com/variety/thunderstorms.html

Days With Thunderstorms are days where a thunderstorm is close enough for thunder to be heard. Top 50 Cities RANK CITY Fort Myers, FL Tampa, FL Tallahassee, FL Gainesville, FL Orlando, FL Mobile, AL W. Palm Beach, FL Lake Charles, LA Daytona Beach, FL Vero Beach, FL Miami, FL Baton Rouge, LA Apalachicola, FL New Orleans, LA Port Arthur, TX Pensacola, FL Jackson, MS Jacksonville, FL Key West, FL Savannah, GA Houston, TX Paducah, KY Montgomery, AL Meridian, MS Charleston AP, SC Charleston, SC Birmingham, AL Fort Smith, AR Little Rock, AR N. Little Rock, AR Shreveport, LA Augusta, GA Columbus, GA Macon, GA Springfield, MO Chattanooga, TN Huntsville, AL Topeka, KS Wichita, KS Tupelo, MS Nashville, TN Columbia, SC Memphis, TN Columbia, MO Flagstaff, AZ Athens, GA Kansas City, MO Colorado Springs, CO Peoria, IL 6 Others Tied DAYS SCORE Introduction Data Diurnal Temp. Variation Annual Temp. Variation Precipitation Thunderstorms Wind Snow Lowest Score Results Most Variety Least Variety Total Scores Complete Alphabetical List: Where does your city rank?

91. Little Bill Productions but yes, I wrote this No matter how much it thunderstorms for you, You're alwaysa rainbow to someone else. Bill Bright. Dedicated to my sweet friend Marin. http://www.littlebill.net/?rant_id=43

92. Severe Thunderstorms - City Of Fort Collins, Colorado Severe thunderstorms. Definitions. Introduction. thunderstorms affect relativelysmall areas when compared with hurricanes and winter storms. http://fcgov.com/oem/thunderstorms.php

text version services council city code ... office of emergency management search Severe Thunderstorms Definitions thunderstorm n. a transient storm of lightning and thunder, usually with rain and gusty winds, sometimes with hail or snow, produced by cumulonimbus clouds. Also called electrical storm -Webster's New Universal Unabridged Dictionary, 1994 severe thunderstorm -National Weather Service Introduction Thunderstorms affect relatively small areas when compared with hurricanes and winter storms. The typical thunderstorm is 15 miles in diameter and lasts an average of 30 minutes. Nearly 1,800 thunderstorms are occurring at any moment around the world. That's 16 million a year! Despite their small size, all thunderstorms are dangerous. Every thunderstorm produces lightning, which kills more people each year than tornadoes. Heavy rain from thunderstorms can lead to flash flooding. Strong winds, hail, and tornadoes are also dangers associated with some thunderstorms. Of the estimated 100,000 thunderstorms that occur each year in the United States, only about 10 percent are classified as

93. NBC5.com - Weather - Thunderstorms thunderstorms. Many Chicagoans look and dissipates. You probably noticethat thunderstorms seem to last longer than 20 minutes. That's http://www.nbc5.com/weather/1202192/detail.html

Search Help You Need Automotive Travel Education ... Weather Email This Story Print This Story Thunderstorms Many Chicagoans look forward to the end of winter and the start of warmer weather. However, our warm season brings the threat of violent weather from powerful thunderstorms which includes deadly lightning, flash flooding, high winds and tornadoes. You feel the winds picking up and sense the moisture in the air. You can see the lightning in the distance and hear the thunder. But what is a thunderstorm? The answer is in the sky. Rising air, called an updraft, lifts moisture into the air to form clouds. When the clouds bubble upward and build in one area, water droplets begin to grow within the cloud. These types of clouds are cumulus because the water 'accumulates' in one spot. Water droplets rising in the updraft freeze and combine with ice crystals far above the ground. When these particles get heavy they fall and melt on the way down. The updraft then carries them back up to repeat the process over and over until the particles become so heavy that they fall to the ground as rain. When the rain starts the thunderstorm is considered to be mature. In the mature stage the storm produces lightning and thunder and the cloud is a "cumulonimbus." The process to get to this point takes about 10 minutes. As the rain falls it drags cold air out of the bottom of the thunderstorm which is called a downdraft. After 10 to 20 minutes the single thunderstorm weakens and dissipates.

94. Nashville Area Red Cross - Disaster Tips - Thunderstorm thunderstorms. Are You Ready for a Thunderstorm? Table of Contents. See also Indepth Information about thunderstorms from the National Weather Service. http://www.nashvilleredcross.org/disastertips/thunder.shtml

95. Hazardous Weather - Thunderstorms Severe thunderstorms produce hail the size of dime (3/4 inches) or larger. Severethunderstorms produce straight wind called downbursts of 58 mph or greater. http://www.floridadisaster.org/hwa03/thunderstorms.htm

HOME LIGHTNING HURRICANES FLOODS ... PRINTER FRIENDLY Severe thunderstorms produce hail the size of dime (3/4 inches) or larger. Dime-sized hail or larger can cause significant damage to the exterior surface of your vehicle, break windows and damage roofs of homes and businesses. Dime-sized hail or larger can cause significant bodily injuries such as broken bones and even blindness if wind blown. Softball-sized hail was reported in Lake Wales, Florida on March 30, 1996. Hailstones the size of softballs can fall at speeds faster than 100 mph. Haildrifts, up to four feet deep of dime- to nickel-sized hail, occurred in low-lying areas near Zephyrhills, Florida on January 29, 1997. Severe thunderstorms produce straight wind called downbursts of 58 mph or greater. Downbursts have been measured in excess of 100 mph. Downbursts can cause significant damage even to well-constructed homes, topple or snap large trees, blow down road and commercial signs, and remove roofs from structures. Downbursts can cause damage similar to that of a strong tornado, and cause loss of life or significant bodily injury from wind blown debris and toppled structures.

96. Thunderstorms And Lightning thunderstorms AND LIGHTNING thunderstorms affect relatively small areas when comparedwith hurricanes and winter storms. thunderstorms AND LIGHTNING SAFETY. http://www.pascocountyfl.net/oem/thunders.asp

Pasco County Office of Emergency Management Emergency Information Personal Preparedness Business Preparedness CERT ... Important Telephone Numbers THUNDERSTORMS AND LIGHTNING Every thunderstorm produces lightning, which kills more people each year than tornadoes. Heavy rain can lead to flooding. Strong winds and tornadoes are also dangers associated with some thunderstorms. Along the Gulf Coast, most thunderstorms occur during the afternoon. Lightning causes an average of 93 deaths and 300 injuries annually and causes several hundred million dollars in damage. Florida leads the nation in the number of lightning death and injuries. Flash Floods/Floods cause 140 fatalities each year. Most flash flood deaths occur when people become trapped in their automobiles. Tornadoes Straight line winds are responsible for most thunderstorm wind damage. A small area of rapidly descending air beneath a thunderstorm can cause damaging winds in excess of 100 mph. The strong winds usually approach from one direction and may be known as "straight line" winds. One type of straight line winds, the downburst (above), can cause as much damage as a strong tornado. 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

97. ABCNEWS.com : Arctic Thunderstorms: New Signs Of Warming visit hp.com. GO TO Select a Topic. http://abcnews.go.com/sections/science/DailyNews/arctic_thunder001115.html

Good Morning America World News Tonight Downtown Primetime ... ABCNEWS.com var flash = 0; var ShockMode = 0; var Flash_File_Path = "http://akaads-abc.starwave.com/ad/sponsors/compaq/comp-log0302/comp-log0302.swf"; var default_image = "http://akaads-abc.starwave.com/ad/sponsors/compaq/comp-log0302/comp-log0302.gif"; var default_alttext = "visit hp.com"; var ad_width = "95"; var ad_height = "30"; on error resume next FlashInstalled = (IsObject(CreateObject("ShockwaveFlash.ShockwaveFlash.4"))) If FlashInstalled = "True" then flash = 1 End If GO TO: Select a Topic Sci/Tech Index HOMEPAGE SCIENCE FEATURE Arctic Changes Thunder Storms Are Latest Evidence of Climate Change The Associated Press O T T A W A, Nov. 15 Electric storms in the upper Arctic are among the evidence of climate change being reported in a new study by the International Institute for Sustainable Development, based in Winnipeg, Manitoba. The release of the study this week coincides with a U.N. conference on global warming being held in The Hague, Netherlands. The study focuses on knowledge among Inuits of changes in the Arctic environment. Researchers spent a year visiting Sachs Harbour on Banks Island in the Northwest Territories, accompanying Inuit people on their hunting and fishing trips and recording their observations.

98. Heavy Thunderstorms Pound Country ­ With More To Follow Lebanese news. Heavy thunderstorms pound country ­ with more to follow BeirutAirport warns of rain, snow and high winds continuing till Friday night http://www.dailystar.com.lb/14_02_03/art5.asp

99. AHG: Thunderstorms And Lightning thunderstorms affect relatively small areas when compared with hurricanesand winter storms. strike. thunderstorms AND LIGHTNING SAFETY. http://www.co.hernando.fl.us/em/thunder.htm

Click Here to find out current emergency information. About Emergency Management Emergency Phone Numbers ... Community Emergency Response Team (CERT) Emergency Notification System Request Information FEMA For Kids ... Storage Tanks Program Hernando County Emergency Management 20 North Main Street Room 362 Brooksville, FL 34601 Fax (352) 754-4090 Danny Roberts Interim Emergency Management Director DanielR@co.hernando.fl.us

100. American Red Cross Of Greater Chicago Thunderstorm Safety Tips. Before Lightning Strikes • Keep an eye on thesky. Look for darkening skies, flashes of light, or increasing wind. http://www.chicagoredcross.org/getprepared/thunderstorms.htm

Get Prepared Make a Disaster Plan Build an Emergency Supply Kit Get Trained Understanding Threat Levels Safety Products First Aid Kits AEDs Emergency Supply Starter Kits Lifeline ... Masters of Disaster Safety Tips Fire Safety Floods Heat Waves Thunderstorms ... Workplace Safety Thunderstorm Safety Tips Before Lightning Strikes When a Storm Approaches If Caught Outside After the Storm Passes If Someone is Struck by Lightning

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