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Meteorology
This event emphasizes understanding of basic meteorological principles with
emphasis on interpretation and analysis of meteorological data.
Read the Rules
• Team of up to 2• One 81/2” by 11” two sided page of notes
containing information in any form from any source.
• Read the Rules• READ THE RULES!!!!!
Watch the weather on the news
• News programs show current weather maps, trends, radar
• Watch the news
Go to NOAA.gov
The Modern Atmosphere
Composition
Seasons
Solar Radiation
meteogram
Aurora Borealis – taken by a NWS employee
Symbols
Weather Maps
Conceptual Model of Lightning Charge Distribution Within a Thunderstorm For many years, scientists have thought thunderstorms contain three charges, called a tripole. A new conceptual model of electrical charge distribution inside deep convection (thunderstorms), developed by NSSL and university scientists, could change that thinking. In the main updraft (in
and above the red arrow), there are four main charge regions. In the convective region but outside the outdraft (in and above the blue arrow), there are more than four charge regions.
• Lightning types • GROUND FLASHES
There are two categories of ground flashes: natural (those that occur because of normal electrification in the environment), and artificially initiated or triggered. Artificially initiated lightning includes strikes to very tall structures, airplanes, rockets and towers on mountains. Triggered lightning goes from ground to cloud, while "natural" lightning is cloud to ground.
• Terms used to describe ground flashes include forked lightning, which shows branching to the ground from a nearly vertical channel; ribbon lightning, when the horizontal displacement of the channel by the wind appears as a series of ribbons; and bead lightning, when the decaying channel of a ground flash will sometimes break into a series of bright and dark spots. Ball lightning is a luminous sphere whose physics is not well understood.
Natural
Triggered
Winter• Winter Weather Basics• How do winter storms form? • Just like any other storm at other times of the year, just the right
combination of ingredients is necessary for a winter storm to develop.• Three basic ingredients are necessary to make a winter storm. • Cold air – below freezing temperatures in the clouds and near the ground
are necessary to make snow and/or ice. • Lift – something to raise the moist air to form the clouds and cause
precipitation. An example of lift is warm air colliding with cold air and being forced to rise over the cold dome. The boundary between the warm and cold air masses is called a front. Another example of lift is air flowing up a mountainside.
• Moisture – to form clouds and precipitation. Air blowing across a body of water, such as a large lake or the ocean, is an excellent source of moisture.
Winds• Types of damaging winds• Straight-line winds – a term used to define any thunderstorm wind that
is not associated with rotation, and is used mainly to differentiate from tornadic winds.
• Downdrafts – A small-scale column of air that rapidly sinks toward the ground. A downburst is a result of a strong downdraft.
• Downbursts – A strong downdraft with horizontal dimensions larger than 4 km (2.5 mi) resulting in an outward burst or damaging winds on or near the ground. (Imagine the way water comes out of a faucet and hits the bottom of the sink.) Downburst winds may begin as a microburst and spread out over a wider area, sometimes producing damage similar to a strong tornado. Although usually associated with thunderstorms, downbursts can occur with showers too weak to produce thunder.
Doppler Radar
• Derecho – A derecho is a widespread thunderstorm wind event caused when new thunderstorms form along the leading edge of an outflow boundary (a surface boundary formed by the horizontal spreading of thunderstorm-cooled air). The thunderstorms feed on this boundary and continue to reproduce themselves. Derechos typically occur in the summer months when complexes of thunderstorms form over the plains and northern plains states. Usually these thunderstorms produce heavy rain and severe wind reports as they rumble across several states during the night. The word "derecho" is of Spanish origin and means "straight ahead". They are particularly dangerous because the damaging winds can last a long time and can cover such a large area.
• Bow Echo – A radar echo which is linear but bent outward in a bow shape. Damaging straight-line winds often occur near the "crest" or center of a bow echo. Bow echoes can be over 300km in length, last for several hours, and produce extensive swaths of wind damage at the ground.
• ..\SO workshop\2005_illinois_regional_exam.pdf
