Forecasting Weather Notes
Conditions measured for forecast
1. Air pressure
- if rises, air mass moves over. (improving weather)
-if falls, a front or low pressure is approaching, often precipitation.
(a change in weather)
2. Wind direction
-winds shift from southwest to northwest a cold front is located.
-winds shift from east to southeast a warm front is located.
3. Clouds
-cirrus to cirrostratus and altostratus is a warm front and
rain for a long time.
-cirrus to dark cumulonimbus is a cold front and a violent storm
but not for a long time.
4. Wind speed
5. Temperature
-dropping temperature is a clue to a cold front.
-rising temperature is a clue to a warm front.
Weather Maps – overall picture of weather across the earth.
-local conditions to national weather service 8 times a day.
-Station Model- group of symbols, shows weather.
- measures the following from ground to make surface map.
Temperature
Air pressure
Wind speed
Wind direction
Dew point
Visibility
Cloud cover
Cloud type
Precipitation
Steps to produce a surface map.
1. station models printed on map
2. isobars are drawn
a. circled areas that represent lowest pressure and labeled lows
b. smaller circled areas that represent highest pressure and labeled highs
3. isotherms are drawn in occasionally.
4. meteorologist analyze map, mark the line for fronts and shade
precipitation.
Movement of weather systems- are in straight lines unless acted upon by
another air mass.
1. pattern of movement shows both direction and speed of system.
2. forecast based on prediction of position of system.
-forecast only accurate for about 12 hours.
-long-range forecasts- very general
based on seasonal averages of temperature and pressure and winds
in upper troposphere.
How can we find information on weather patterns?
1. ground readings
2. buoys take radio readings
3. ships report conditions
4. satellites
5. Radar
6. Doppler radar