All thunderstorms require three main ingredients:
Typical sources of moisture are large bodies of water such as the Atlantic and Pacific oceans, as well as the Gulf of Mexico. Water temperature also plays a large role in how much moisture is in the atmosphere. Evaporation is higher in warm ocean currents and therefore they put more moisture into the atmosphere than with cold ocean currents at the same latitude.
Air is considered unstable if it continues to rise when given a nudge upward (or continues to sink if given a nudge downward). An unstable air mass is characterized by warm moist air near the surface and cold dry air aloft.
In these situations, if a bubble or parcel of air is forced upward it will continue to rise on its own. As this parcel rises it cools and some of the water vapor will condense forming the familiar tall cumulonimbus cloud that is the thunderstorm.
3. A Lifting Mechanism
Typically, for a thunderstorm to develop, there needs to be a mechanism which initiates the upward motion, something that will give the air a nudge upward. This upward nudge is a direct result of air density.
Some of the sun's heating of the earth's surface is transferred to the air which, in turn, creates different air densities. The propensity for air to rise increases with decreasing density. This is difference in air density is the main source for lift and is accomplished by several methods (differential heating, terrain, fronts, dry lines and outflow boundaries)
Why can different types of precipitation be seen on Earth while temperatures remain constant?
Dangerous flash flooding is captured as an arroyo becomes filled with water in Carson Valley, Nevada.
The RealFeel Temperature uses an equation to determine how it actually feels outside.
Knowing what the different advisories, watches, and warnings mean will lead to more informed decision making when a winter storm threatens a particular area.
How can you determine if and when the ice is thick enough for safely going out on?
Seeking shelter in the event of a tornado could save your life, but is there really any safe place to hide?
Driving on a 90-degree angle away from the tornado is a good strategy to follow in order to distance yourself from the tornado.
Supercell thunderstorms have been responsible for major tornadoes that have demolished parts of the U.S.
After a cold, clear winter night without much wind, the ground and nearby tree branches may be covered by tiny, white ice crystals.
A major cause of post-snow flooding are ice jams in waterways.
Los Angeles, CA (1955)
110 degrees, hottest day ever in September. This mark was tied September 4, 1988.
Milwaukee, WI (1988)
Hottest summer on record. Six days of 100 degrees or greater and 36 days of 90 or above. Average temperature of 73.8 beat the old record of 72.8 set in 1921 and 1955. The normal average tempera- ture for a summer in Milwaukee is 68.3 degrees.
Washington Co., IA (1897)
Hail fell and drifted in piles 6 feet deep in Washington County.