Weather Station Models Isobars & Isotherms

1. Weather Station ModelsIsobars & Isotherms

2. What do Weather Map Symbols look like?

3. What does a weather station tell us? • The sky around the weather observation station including the amount of cloud cover • The present weather conditions including precipitation type and amount. • The visibility (measured in miles) • The air temperature and dew point (both in degrees Fahrenheit • The wind speed and direction • The barometric pressure (measured in millibars) and the pressure trend.

4. Cloud Cover • Cloud cover is represented by a pie graph. The amount of the circle that is dark is used to indicate the portion of the sky covered by clouds. It can be empty (0%), shaded by 25%, 50%, 75% or 100%.

5. Temperature • Temperature, also known as dry bulb temperature, will always be the first number written on the upper left hand side of the model.

6. Dew Point • Dew point is the temperature at which the air would be saturated with water vapor. Although dew point is a temperature it is an indicator of the absolute humidity.

7. Wind Direction • A line connected to the circle indicates wind direction. Remember wind is always named according to the direction it is coming from.

8. Barometric Pressure • Barometric (air) pressure is recorded as a three digit number. It helps to realize that the normal barometric pressure at Earth’s surface is generally 1000 millibars (mb).

9. How to Interpret Barometric (Air) Pressure • Study This!!!!!! • If the three digit code is less than 500 (499 or less) add a 10 at the beginning and a decimal point before the last number. • If the three digit code is greater than 500 (500+) add a 9 before the number and a decimal before the last digit.

10. Practicing Interpreting Barometric Pressure Decode these coded pressures: 002 = _______ 993 = _______ 280 = _______ 000 = _______ 480 = _______