Weather Part IVStorms

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