JERI

media type="file" key="Ilene and Josangel 613 Puerto Rico.wmv" width="300" height="300"IS.347 JERI RODRIGUEZ .CLASS 613 3/6/12

When the clouds change into cumulonimbus clouds, the water droplets start to merge with one another, the clouds become heavier, and water begins to freeze. As the ice falls, it melts and turns to rain which produces a downdraft. This turbulence between updrafts and downdrafts creates wind, positive and negative charges make lightning, and tornadoes may possibly form.
 * Thunderstorms start when hot air rises from the ground (thermals) and causes clouds to rise. As the air cools with the higher elevation, water condenses and forms droplets. The water condenses and heat is produced, heating the air and causing an updraft of air. This updraft causes a low pressure area beneath the thunderstorm.
 * Thunderstorms start when hot air rises from the ground (thermals) and causes clouds to rise. As the air cools with the higher elevation, water condenses and forms droplets. The water condenses and heat is produced, heating the air and causing an updraft of air. This updraft causes a low pressure area beneath the thunderstorm.
 * Thunderstorms start when hot air rises from the ground (thermals) and causes clouds to rise. As the air cools with the higher elevation, water condenses and forms droplets. The water condenses and heat is produced, heating the air and causing an updraft of air. This updraft causes a low pressure area beneath the thunderstorm.
 * Thunderstorms start when hot air rises from the ground (thermals) and causes clouds to rise. As the air cools with the higher elevation, water condenses and forms droplets. The water condenses and heat is produced, heating the air and causing an updraft of air. This updraft causes a low pressure area beneath the thunderstorm.
 * Thunderstorms start when hot air rises from the ground (thermals) and causes clouds to rise. As the air cools with the higher elevation, water condenses and forms droplets. The water condenses and heat is produced, heating the air and causing an updraft of air. This updraft causes a low pressure area beneath the thunderstorm.

Lightning and thunder are a big part of a thunderstorm. As the turbulence increases inside the storm, the water droplets and ice crystals break up and become electrically charged. The upper part of the cumulonimbus clouds is positively charged, and the middle and bottom portion of the cloud is negatively charged. Lightning happens when a discharge occurs between the cloud and the earth’s surface. When the lightning heats the air, it expands quickly, and the rumbling of thunder is created.

Tornado Formation
Before a thunderstorm forms, there is an area in the lower atmosphere of horizontal, spinning air caused by a change in wind direction and an increase in the wind’s speed along with an increase in height. When the thunderstorm starts to develop, the updraft lifts this area of spinning air, changing its pitch from horizontal to vertical. At this point, there is a large area of rotation, from two to six miles in diameter, where the tornado typically forms. A wall cloud will form, a low mass of clouds which rotates. A tornado forms, which is accompanied by high winds and damaging hail. These dark green clouds that indicate a possibly tornadic storm occur often in Tornado Alley. This is an area where many tornadoes are formed, and includes parts of Nebraska, Kansas, Oklahoma, and Texas. One thing that contributes to tornadoes is unstable air. When warm air rises, the atmosphere is considered unstable. When the air is cooler than the surrounding air, it will sink and the atmosphere is said to be stable. A thunderstorm cannot develop in stable conditions.

Supercells
Supercells are very large, rotating thunderstorms. They can live a very long time and spawn several tornadoes. Tornadoes formed from supercell thunderstorms are more damaging partly because of their duration. One kind of supercell creates huge amounts of precipitation and large, damaging hail. The other kind produces less precipitation and large hail but makes tornadoes. Squall lines form from the border between warm and cold fronts or from a storm that has split. Most of the precipitation in the United States comes from a squall line. One kind of squall line that can develop is a line of supercell storms. Sometimes a squall liner can reach over 600 miles in length. So a further answer to, “How do tornadoes form?” is they can form in a squall line of supercells, and each supercell can form several tornadoes.

Watches and Warnings
A tornado watch means that conditions are favorable for the formation of a tornado. It implies a severe thunderstorm warning, as any thunderstorm capable of producing a tornado will be severe. Usually, there will also be a threat for large hail and high winds. When a watch is issued, stay alert to changing weather conditions, especially looking for dark green clouds or orange-gray skies, hail, rotating clouds or funnels, and listen for a loud roar. Also, stay tuned to local weather updates and be ready to take action quickly. A tornado warning means that either storm spotters have seen a funnel, or radar is indicating a possible funnel. Tornado sirens may sound in your area. You will need to take shelter immediately and listen for updates. If you are outside, go to a low-lying area, like a ravine or ditch and cover your head with your hands. Do not take shelter under an overpass. If you are in a trailer or car, seek shelter in a building immediately. If you are in a building, go to the basement or lowest floor and go to the center of an interior room, like a closet, bathroom, or hallway that is away from windows, doors, corners, and outside walls. || A tornado near [|Anadarko, Oklahoma]. The funnel itself is the thin tube reaching from the __cloud__ to the ground. The lower part of this tornado is surrounded by a [|translucent] dust cloud, kicked up by the tornado's strong winds at the surface. Note that the actual wind of the tornado has a much wider radius than the funnel. A **tornado** is a violent, dangerous, rotating column of air that is in contact with both the surface of the earth and a [|cumulonimbus cloud] or, in rare cases, the base of a [|cumulus cloud]. They are often referred to as a **twister** or a **cyclone**,[|[][|1][|]] although the word [|cyclone] is used in meteorology in a wider sense, to name any closed [|low pressure] circulation. Tornadoes come in many shapes and sizes, but are typically in the form of a visible [|condensation funnel], whose narrow end touches the earth and is often encircled by a cloud of [|debris] and [|dust]. Most tornadoes have wind speeds less than 110 miles per hour (177 km/h), are approximately 250 feet (76 m) across, and travel a few miles (several kilometers) before dissipating. The [|most extreme] tornadoes can attain wind speeds of more than 300 mph (480 km/h), stretch more than two miles (3.2 km) across, and stay on the ground for dozens of miles (more than 100 km).[|[][|2][|]][|[][|3][|]][|[][|4][|]] Various types of tornadoes include the [|landspout], [|multiple vortex tornado], and [|waterspout]. Waterspouts are characterized by a spiraling funnel-shaped wind current, connecting to a large cumulus or cumulonimbus cloud. They are generally classified as non-[|supercellular] tornadoes that develop over bodies of water.[|[][|5][|]] These spiraling columns of air frequently develop in tropical areas close to the [|equator], and are less common at [|high latitudes].[|[][|6][|]] Other tornado-like phenomena that exist in nature include the [|gustnado], [|dust devil], [|fire whirls], and [|steam devil]. Tornadoes have been observed on every continent except Antarctica. However, the vast majority of tornadoes in the world occur in the [|Tornado Alley] region of the [|United States], although they can occur nearly anywhere in North America.[|[][|7][|]] They also occasionally occur in south-central and eastern Asia, the [|Philippines], south east Asia, like [|Malaysia],[|[][|8][|]] northern and east-central South America, [|Southern Africa], northwestern and southeast Europe, western and southeastern Australia, and New Zealand.[|[][|9][|]] Tornadoes can be detected before or as they occur through the use of [|Pulse-Doppler radar] by recognizing patterns in velocity and reflectivity data, such as [|hook echoes], as well as by the efforts of [|storm spotters]. There are several different scales for rating the strength of tornadoes. The [|Fujita scale] rates tornadoes by damage caused, and has been replaced in some countries by the updated [|Enhanced Fujita Scale]. An F0 or EF0 tornado, the weakest category, damages trees, but not substantial structures. An F5 or EF5 tornado, the strongest category, rips buildings off their foundations and can deform large [|skyscrapers]. The similar [|TORRO scale] ranges from a T0 for extremely weak tornadoes to T11 for the most powerful known tornadoes.[|[][|10][|]] Doppler [|radar] data, [|photogrammetry], and ground swirl patterns ([|cycloidal] marks) may also be analyzed to determine intensity and assign a rating.[|[][|11][| a near tornado was near anaddarko/oklahoma . tornado is a thin tube reaching down to ground from the cloud .the low part of the tornado is surrounded by a cloud dust.a tornado perform by hot air n cold air goes in to each other.the fast the tornado can go is 300mph.and the tornado height 250 feet away from the ground.tornado can damage any thing that's in front of it.