Weather Part IV Storms Reference: CK-12.org Earth Sciences Chapter 16 By: Robert Smith

Weather Forcasting According to the World Meteorological Organization (WMO), a 5-day weather forecast today is as reliable as a 2-day forecast was 20 years ago

Thermometers Thermometers measure temperature modern thermometers use a coiled strip composed of two kinds of metal, each of which conducts heat differently. Modern thermometers usually produce digital data

Barometers barometers to measure air pressure Modern meters are all digital change in barometric pressure indicates that a change in weather is coming pressure falls, a low pressure cell is coming air pressure rises, a high pressure cell is on the way Barometric pressure data over a larger area can be used to identify pressure systems, fronts, and other weather systems

Weather Station Weather stations contain some type of thermometer and barometer Other instruments measure different characteristics of the atmosphere such as wind speed, wind direction, humidity, and amount of precipitation weather information is collected from 15 satellites, 100 stationary buoys, 600 drifting buoys, 3,000 aircraft, 7,300 ships, and some 10,000 land-based stations

Radiosondes Radiosondes measure atmospheric characteristics, such as temperature, pressure, and humidity as they move through the air dropped from a balloon or airplane to make measurements as they fall.

Radar stands for Radio Detection and Ranging transmitter sends out radio waves that bounce off the nearest object and then return to a receiver Doppler radar can also track how fast the precipitation falls Outline the structure of a storm

Satellites observe all energy from all wavelengths in the electromagnetic spectrum. Visible light images record storms, clouds, fires, and smog Infrared images record clouds, water and land temperatures

Automation most accurate weather forecasts are made by advanced computers have up-to-date mathematical models that can use much more data and make many more calculations than would ever be possible by scientists

Weather Maps depict meteorological conditions in the atmosphere depict information from computer models or from human observations many different symbols as a quick and easy way to display information on the map

Map terms Lines of equal temperature are called isotherms – Can indicate fronts Isobars are lines of equal average air pressure at sea level – Indicate high and low pressure cells Isotachs are lines of constant wind speed – Low values high in the atmosphere indicate cyclone warning – High wind speeds high in the atmosphere indicate the jet stream’s location