61. BoM - Warning Message Warning Message. Please Note the Severe thunderstorms in New South Wales websitehas moved to http//www.bom.gov.au/weather/nsw/sevwx/index.shtml. http://www.bom.gov.au/weather/nsw/inside/sevwx/public/

Weather: National Victoria NSW ACT ... Tasmania Warning Message Please Note: the Severe Thunderstorms in New South Wales website has moved to http://www.bom.gov.au/weather/nsw/sevwx/index.shtml . Please update your links. Note, you will be redirected to the new location in 15 seconds If you have waited more then 15 seconds and you are still seeing this message, please click on the new URL mentioned above!. Home Learn about Meteorology Publications News ... SILO Commonwealth of Australia 2003, Commonwealth Bureau of Meteorology (ABN 92 637 533 532) Users of these web pages are deemed to have read and accepted the conditions described in the Please also note the Acknowledgements notice relating to the use of the information on this site and our site

62. National Weather Service - San Francisco Bay Area - Tornadoes And Thunderstorms Storm Spotters. Tsunami/Quakes. thunderstorms. NOAA Wx Radio. StormReady. FAQ. MoreFAQs. Useful Links. Contact Us. wsfomtr@noaa.gov. ..TORNADOES AND thunderstorms. http://www.wrh.noaa.gov/Monterey/tornado.html

www.nws.noaa.gov Search field for weather information. Press Enter or select the go button to submit request Search by city and state. Press enter or select the go button to submit request Current Hazards Local Warnings Nationwide Outlooks Storm Report Current Conditions Observations Camera Views Buoy Reports Satellite Images ... Rainfall Totals Forecasts Area Forecasts Prototype Digital Forecast Aviation ... Winter Weather Climate Local Data Co-op Program Sun/Moon/Tides Climate Outlook Weather Safety Storm Spotters Tsunami/Quakes Thunderstorms NOAA Wx Radio ... TsunamiReady Miscellaneous Local Projects PACJET 2003 FAQ More FAQs ... Useful Links Contact Us wsfomtr@noaa.gov

63. Follow The Trail To . . . Among the most dramatic weather features in eastern Colorado are thegiant thunderstorms that develop from May through September. http://www.ucar.edu/exhibits/wxtrail/tstorms.html

Among the most dramatic weather features in eastern Colorado are the giant thunderstorms that develop from May through September. On a typical day in late spring or summer, cumulus clouds develop by early afternoon. They are driven by the heating of low-level air and resulting instability. These fleecy clouds can build into towering cumulus and sometimes into powerful cumulonimbus (thunderheads). Often the storms will develop over the mountains near Boulder, then move eastward onto the plains by late afternoon, growing stronger with time. Most storms last from one to two hours, although a few (called supercells) can survive for more than six hours. Tornadoes and large hail sometimes occur with these storms. Large hail is rare in Boulder, but tornadoes east of town can occasionally be seen from the NCAR mesa. Lightning is always a danger, even from the weakest thunderstorm. The best protection from lightning is shelter-inside a building or automobile, but not under a tree. Follow the trail to . . . Brown Cloud Climate Zones Cold Fronts Fire and Drought ... Sunshine and Ultraviolet Light Thunderstorms Wind Weather Trail Home Page NCAR Visual Communications Programs Special Events ... Explore Newsletter

64. Tornadoes & Thunderstorms thunderstorms Tornadoes Hurricanes Blizzards Winter Weather Clouds. Predict the weather! http://www.ucar.edu/educ_outreach/webweather/thunderhome.html

[Hurricanes] [Clouds] [Predict the weather! [Hurricanes] [Clouds] [Predict the weather!

65. In The Clouds Photography - Weather Gallery (supercells) Supercell thunderstorms Supercell thunderstorms refer to thunderstormswhich are rotating. Most, but not all, supercells rotate http://www.inclouds.com/Wx/supercell.html

PREV NEXT Home Gallery Information Search Feedback ... Photo Tips Supercell Thunderstorms: Supercell thunderstorms refer to thunderstorms which are rotating. Most, but not all, supercells rotate cyclonically (counter-clockwise in the northern hemisphere). Rotation is produced by wind shear (a change in wind speed and/or direction with height) and exists for the updraft portion or the entire scale of the storm (usually from a few to tens of kilometers horizontally and five to twelve kilometers vertically). Suggested Reading: Storms . ASTeR Press Inc. Tornado Alley. Monster Storms of the Great Plains . Oxford University Press Weather Gallery (Page 4 of 6): Supercell Thunderstorms PREV: NEXT: Tornadoes

66. Weather.com - Encyclopedia - Thunder Severe thunderstorms thunderstorms that precede a cold front are generally strongerand more likely to reach severe proportions than localized thunderstorms http://www.weather.com/encyclopedia/thunder/svrtstm.html?from=newscenter

67. About - Thunderstorms ABOUT thunderstorms Home. What are thunderstorms? Facts about thunderstorms,thunderstorms have an average lifetime of 20 to 30 minutes. http://www.stormchasing.nl/thunder.html

Team Floris Bijlsma Herman Harperink Calendar ... Contact ABOUT THUNDERSTORMS Home What are thunderstorms? When a Cumulonimbus or stormcloud produces lightning, we speak of a thunderstorm. Thunderstorms are often accompanied by wind gusts, hail and torrential rainfall. In some cases, a severe thunderstorm can also produce a tornado. Later in this document, the different types of thunderstorms are discussed. How does a storm form? A brief introduction: For a storm to develop, a few boundary conditions are needed. The first one is an unstable column of air. There are different types of instability, but in general it means that the air rises spontaneously. Instability can be the result of heating of the surface (or cooling of the upper atmosphere): a thermal instability . Or it can have a dynamic cause, such as in a frontal system. This type of instability is called dynamic instability . These two types of instability can influence each other. The second condition we need for the development of a storm is moisture. There has to be enough available water in the boundary layer for condensation so a cloud can form. Dry layers in the upper atmosphere can cause entrainment.

68. Thunderstorms thunderstorms affect relatively small areas when compared to winter storms. However,despite their small size all thunderstorms are dangerous. http://www.state.il.us/iema/Thunderstorms.htm

Current Illinois Weather Current Road Conditions IEMA Employment Opportunities IEMA 110 East Adams Springfield, Illinois 62701-1109 Laws and Regulations Thunderstorms affect relatively small areas when compared to winter storms. The typical thunderstorm is 15 miles in diameter and lasts an average of 30 minutes. However, despite their small size all thunderstorms are dangerous. They are most likely to happen in the spring and summer months during the afternoon and evening hours but can occur any time of the year and day. All thunderstorms produce lightning which causes extensive damage to property and kills more people each year than tornadoes. Lightning poses a significant threat in Illinois having killed twenty-one people between 1985 and 1997 and injuring dozens more. Most lightning casualties occur in the summer during the afternoon. Most victims are outdoors under a tree, in an open field, near a vehicle or a building. People are also injured indoors when on the telephone, using appliances, or taking a bath/shower. Flash floods and floods produced by thunderstorms are the nation's number one killer, claiming nearly 140 lives each year. Most casualties occur when motorists try to drive through flooded roadways and are swept away by strong currents. Floods are Illinois' most destructive and widespread natural hazard having caused devastating damages to structures, utility services and crops.

69. NCDC: Satellite Events Art Gallery: Thunderstorms NCDC / Products Publications / Satellite Gallery / thunderstorms / SAA / SearchNCDC, Thunderstorm Exhibits. Satellite Images of Other thunderstorms. http://www.ncdc.noaa.gov/oa/satellite/satelliteseye/thunderstorms/thunderstorms.

NCDC Satellite Gallery / Thunderstorms / SAA Search NCDC Thunderstorm Exhibits Location Date Ohio August 17, 1997 Satellite Images of Other Thunderstorms NCDC Satellite Gallery / Thunderstorms / SAA Search NCDC http://www.ncdc.noaa.gov/oa/satellite/satelliteseye/thunderstorms/thunderstorms.html Downloaded Sunday, 23-Mar-2003 01:16:43 EST Last Updated Wednesday, 12-Sep-2001 16:06:48 EDT by Sam.Mccown@noaa.gov Please see the NCDC Contact Page if you have questions or comments.

70. NCDC: Satellite Events Art Gallery: Thunderstorms Ohio thunderstorms. August 17, 1997. Data Type, Sector. Event Discussion. Ohiothunderstorms / August 17, 1997. Figure 1 Visible Image. Figure 2 Infrared Image. http://www.ncdc.noaa.gov/ol/satellite/satelliteseye/thunderstorms/ohio97/ohio97.

NCDC Satellite Gallery Thunderstorms / Ohio, August 1997 / SAA Search NCDC Ohio Thunderstorms August 17, 1997 Visible Image Enlarged Image East Coast Image MPEG Loop (1300-1700 EDT) Image Information Event Discussion Infrared Image Enlarged Image East Coast Image MPEG Loop (1300-1700 EDT) Image Information Event Discussion Water Vapor Image Enlarged Image East Coast Image MPEG Loop (1300-1700 EDT) Image Information Event Discussion Strong thunderstorm complexes developed over Ohio and Kentucky on the afternoon of August 17, 1997 and pushed to the East Coast by midnight. The gallery presents visible, infrared, and water vapor images, all taken at 19:15 UTC (15:15 EDT). Within 15 minutes on either side of the time when the series of satellite images were taken, downbursts from the thunderstorms had caused tree damage and power outages in seven counties. Image Information Satellite System Image Specifics Satellite Name GOES 8 Channel Band No. 1 (Visible) No. 4 (Infrared) No. 3 (Water Vapor) Date August 17, 1997 Resolution 1-km (Visible) 4-km (Infrared) 8-km (Water Vapor) Julian Date Orbit No./Dir

71. Thunderstorms thunderstorms. In the Nordic countries, where the cloud height may be verylow there exists thunderstorms as well in summer as in winter. http://thunder.hvi.uu.se/NCLR/thunderstorms.html

Thunderstorms The properties of lightning discharges depend on the properties of the electrically charged thunderclouds. In the Nordic countries, where the cloud height may be very low there exists thunderstorms as well in summer as in winter. It has been observed that lightning from winter thunderstorms is often of positive polarity with a very high amplitude. The frequency of long-lasting lightning currents which are necessary for ignition of forest fire are also expected to depend on the properties of the thundercloud. Therefore it is important to study the particular properties of the Nordic thunderstorms. This is best done in close cooperation between the meteorologists in the different countries. Back to NCLR

72. Thunderstorms thunderstorms. What causes a thunderstorm? thunderstorm, thunderstorms,severe thunderstorms, lightning thunderstorm, tornados thunderstorms http://www.stormwarn.com/rants/thunderstorm_genesis.html

THUNDERSTORMS What causes a thunderstorm? thunderstorm thunderstorms severe thunderstorms lightning thunderstorm ... convection By the founder of StormWarn! Go to StormWarn!

73. SEVERE WEATHER PREPAREDNESS: Thunderstorms thunderstorms BEFORE Know the terms used to describe severe thunderstormthreats Severe Thunderstorm Watch Severe thunderstorms are possible. http://www.ag.uiuc.edu/~disaster/storm/sw_thunder.html

Severe Weather Preparedness Series THUNDERSTORMS BEFORE Know the terms used to describe severe thunderstorm threats: Severe Thunderstorm Watch Severe thunderstorms are possible. Watch the sky and listen to radio or television for more information. Be prepared to take shelter. Severe Thunderstorm Warning Severe thunderstorms are occurring. Take shelter, turn on a battery-operated radio or television, and wait for the "all clear" announcement by authorities. Purchase a NOAA Weather Radio with battery backup and tone-alert feature which automatically alerts you when a Watch or Warning is issued. Know the county(s) in which you live and work. The NWS uses county names when watches, warnings, and advisories are issued and broadcast. Check the weather forecast before leaving for extended periods outdoors and postpone plans if severe weather is imminent. Keep a list of emergency phone numbers. Teach children how and when to call 911 for emergency assistance. Choose an out of area contact that separated family members can call to report their whereabouts and condition. Keep important documents and records in a safe deposit box or other secure location.

74. Thunderstorms thunderstorms. Words Music by Nick Walker. More About thunderstorms.Listento a music clip MP3 music clip (stereo) Get the http://www.wxdude.com/tstorms.html

Thunderstorms More About Thunderstorms to a music clip MP3 music clip (stereo) Get the whole song and more Don't have Real Audio? Go here to get it Have you ever noticed lightning in the nighttime? Have you heard the thunder in the afternoon? When you see and hear it, you will know it is the right time To get ready, cause a storm is coming soon. Get ready for some threatening clouds, get ready for a shower; You get ready for a gusty blustery wind. But most of all get ready to see nature show its power. And if you find yourself outside, go in! CHORUS: Thunderstorms, thunderstorms, see the lightning flashing. Thunderstorms, thunderstorms, feel the strong winds blow. The rain will soon fall fiercely when those dark clouds start to form; Oh nothing can compare with thunderstorms. You'll find a thunderstorm whenever cold and warm air clashes, And warmer air below is forced to rise. Clouds become so charged up that they spark electric flashes; Then thunder rolls while rain pours from the skies. (Chorus) It's usually just nature's noisy light show

75. Thunderstorms In The Black Hills Region Black Hills Area thunderstorms A line of thunderstorms in Butte County as seenat sunrise from the shore of Belle Fourche Reservoir on June 13, 1998. http://www.blackhillsweather.com/thunderstorm.html

Black Hills Area Thunderstorms A line of thunderstorms in Butte County as seen at sunrise from the shore of Belle Fourche Reservoir on June 13, 1998. Photo taken by Randee Peterson of Black Hills Online using a Casio digital camera. With average precipitation on the plains surrounding the Black Hills only around sixteen and a half inches per year, the climate is classified as semi-arid. Nonetheless, for a semi-arid climate the region has quite a few thunderstorms and Rapid City averages around forty two a year. While most storms pass with periods of heavy rain, some lighting, and perhaps some small hail, there is a tendency for some of them to become severe. For a thunderstorm to be classified as a severe storm, it must contain hailstones greater than three quarters of an inch in diameter and/or winds in excess of 55 miles per hour. The most common component of thunderstorms in the Black Hills region that would cause them to be classified as severe would be large hail. Whereas tornadoes are more common farther south and east, the Black Hills lie on the northern edge of a part of the United States known for having the highest frequency of storms with large hail annually. As illustrated to the right, this area of high hail frequency has a peak in the southeast part of Wyoming, near Cheyenne, where over eight storms with large hail can be expected each year at any given point. The Black Hills can expect four to six such storms a year at any given location. Most of the hail that falls in the Black Hills is small, but it can fall in such quantity as to whiten the landscape and give the appearance of a freak summer snowstorm. Even small hail, however, can be devastating to crops and gardens when it falls in sufficient quantities. Hailstones in western South Dakota can also get quite large. On June 26, 1998 a hailstorm near Howes in northern Meade County produced hailstones four and a half inches in diameter.

76. Thunderstorms ALL the information you need on tornadoes and thunderstorms. Tons of informationand links, plus my own tornado damage photos. thunderstorms. http://www.geocities.com/CapeCanaveral/Lab/2430/thunder.html

Thunderstorms Thunderstorm Ingredients Thunderstorm Life-Cycle Convective Variables Thunderstorm Types ... Books on Thunderstorms Thunderstorm Ingredients To have a thunderstorm you need three things: 1)instability, 2) some sort of uplifting mechanism, and 3) moisture in the mid to lower levels of the atmosphere. An unstable air mass is warm and moist near the ground and relatively cold and dry in the upper atmosphere. If an air mass is unstable, air which is pushed upward will continue upward. Lift is the mechanism which pushes the air upward. Sources of lift can be cold fronts, mountains, converging air (as in Florida), or differential heating. The most common of these is differential heating. Differential heating takes place when portions of the earth's surface warm more readily than other nearby areas. These "warm pockets" are less dense then the surrounding air and will then rise. The last ingredient is moisture. As air rises in a thunderstorm updraft, moisture condenses into small water drops which form clouds. When the moisture condenses, heat is released into the air, making it warmer and less dense than its surroundings. This lets the updraft continue rising. To table of contents Thunderstorm Life-Cycle There are three stages in a thunderstorm's life. They are the cumulus stage, mature stage, and dissipating stage.

77. CJ's Place Of Interests - Thunderstorms find anything from Astronomy to US Weather, New York Ski reports to Hurricanes, HolidayRecipes to Christmas Projects, Recalls to thunderstorms and tornadoes. http://www.midtel.net/~cjworeth/thunder.html

The Thunderstorm Part 1 of 2 Thunderstorm Warnings Weather Glossary Thunderstorms We must obtain a basic understanding of the thunderstorm before we can hope to understand tornadoes, hail, and other phenomena which are produced by the thunderstorm. Sometimes it is convenient to think of a thunderstorm as a solid object floating in the sky. Actually, a thunderstorm should be thought of as a process which takes heat and moisture near the earth's surface and transports it to the upper levels of the atmosphere. The by-products of this process are the clouds, precipitation, and wind that we associate with the thunderstorm. At any given moment, there are roughly 2,000 thunderstorms in progress around the world. Most of these storms are beneficial, bringing needed rainfall to farmlands and reservoirs. Only a small fraction (less than 1 percent) of these storms is classified as severe, producing large hail 3/4 inch in diameter or larger and/or strong downburst wind gusts of 58 miles an hour (50 knots) or greater. A small fraction of the severe storms produce tornadoes. Thus, although any thunderstorm is theoretically capable of producing severe weather, only a very few storms will actually produce large hail, severe downburst winds, or tornadoes. In the United States, the Florida Peninsula and the southeast plains of Colorado have the highest thunderstorm frequency. Relatively small thunderstorms occur about once a year in Alaska and 2-3 times a year in the Pacific Northwest. Although the greatest severe weather threat in the United States extends from Texas to southern Minnesota, it is important to note that no place in the United States is completely immune to the threats of severe weather.

78. WZZM13.com - Thunderstorms However, not all thunderstorms produce rain that reaches the ground. These dry thunderstormsare most common across the western USA and often spawn wildfires. http://www.wzzm13.com/wxthunderstorms.asp

A look inside a thunderstorm Lightning always precedes thunder because lightning causes thunder. A lightning bolt can heat the air it passes through to temperatures as high as 54,000 degrees Fahrenheit. It is the quick and intense heating of the air that generates shockwaves, which propagate rapidly away from the lightning bolt. These shockwaves become soundwaves as they travel through the air. This is how thunder is produced. Sometimes thunder rumbles on long enough that you see another lightning flash, which could lead to a false conclusion that thunder comes before lightning. When this occurs, you are hearing the thunder from a previous lightning flash. A typical thunderstorm produces a brief period of heavy rain and lasts anywhere from 30 minutes to an hour. However, not all thunderstorms produce rain that reaches the ground. These dry thunderstorms are most common across the western USA and often spawn wildfires. These storms often form high above the ground with a large layer of very dry air between the base of the cloud and the ground. As rain falls from the cloud into the dry air, the rain drops evaporate before they reach the ground. Warm, humid conditions are very favorable for thunderstorm development as strong updrafts feed warm, moist air into thunderstorms. If the air is very unstable, severe thunderstorms with damaging winds, large hail, and sometimes tornadoes erupt. Anything from cold fronts and drylines to afternoon heating by the sun can trigger thunderstorm development

79. Severe And Hazardous Weather - Thunderstorms . Views of Supercell thunderstormsExamine photos of supercell thunderstorms from a distance and up close.......thunderstorms. select image to animate, http://severewx.atmos.uiuc.edu/index.17.html

Home Current Weather Forecast Links Archived Data ... Heat Waves Thunderstorms select image to animate Description Squall Line with Straight-Line Winds on 15 April 1994 The sequence of Doppler radar reflectivity images shows the development of a bow echo within a squall line over eastern Missouri/western Illinois. Note the heavy precipitation (red) on the leading edge of the squall line and the development of a bow shape to the line as it approaches St. Louis in the center of the image. Squall Lines Developing from Outflow Along a Gust Front Multiple squall lines developed across Illinois on 25 June 1997, when outflow from an original squall line triggered new convection. This process repeated throughout the day with three distinct squall lines visible on Doppler radar by 2300 UTC. Courtesy of Brian Jewett, University of Illinois Simulation of a Thunderstorm Forming in a Weak-Shear Environment A numerical model shows the development of a thunderstorm in a weak-shear environment. The white area denotes cloud water. Arrows on the surface denote wind direction; speed is denoted by color with faster colors being yellow and red. After 7200 seconds (120 minutes) the thunderstorm has dissipated. Courtesy of Brian Jewett, University of Illinois

80. THUNDERSTORMS thunderstorms. Up (Too) Close and Personal. As we approached the air refuelingtrack some 5 hours later, a large wall of thunderstorms crossed our path. http://safety.kirtland.af.mil/magazine/htdocs/junmag98/tstorms.htm

Menu Past issues of FLYING SAFETY AF SAFETY MAGAZINES AF SAFETY CENTER HOME Thunderstorms Up (Too) Close and Personal LT COL TIMOTHY H. MINER (USAFR) HQ Air Force Weather Agency It was only my third mission as an aircraft commander. There I was, at 4 o'clock in the morning, at the briefing for a higher-headquarters-directed air refueling mission. My crew and I were to be No. 2 in the cell to refuel the Habu (SR-71) on a very visible mission. We were good to go (a phrase unheard of in those days) until the weather briefer placed a chart of the VIP level 4 and level 5 (see attached chart) thunderstorms all around the air refueling track. We knew something was going to make this a day to remember. It wasn't until 10 minutes later, with the conclusion of the last briefing, that the final slide appeared. "Flying Safety Is Paramount" is all it said. As we approached the air refueling track some 5 hours later, a large wall of thunderstorms crossed our path. Tops to 50,000 feet were reported. One controller said there were reports of tornadoes on the ground. With the SR-71 already airborne and descending from its "hot run" high on the other side of the thunderstorms, there was little to do in our craft but stay in formation behind the lead as he probed the squall line for a path through these weather giants. It was clearly too late to change tracks. As the lead headed for a "saddle"the low portion between large cellsin the squall line of storms, he suddenly turned away just after entering the cloud mass. We turned as soon as we could. Unfortunately, we had already penetrated the clouds, too.

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