Interpreting Weather Station Data
Name_____________________
Hour______
Background:
What is the weather now? What is the weather going to be in the next few hours?
Weather is the state of the atmosphere at a particular time and place, mainly with
respect to its impact on life and human activity. It is defined by the various weather
elements including air temperature, humidity, cloudiness, precipitation, visibility, air
pressure and wind speed/direction. The surface weather map is a useful tool for
depicting weather conditions at many locations over a broad area.
After completing this activity, you should be able to:
Decode the symbols appearing on a surface weather map and describe weather
conditions at various locations on the map.
Describe general relationships between weather conditions at neighboring locations
within regions shown on weather maps.
Activity:
1. Some weather maps display weather conditions at individual weather stations by the
use of a station model. In the model, weather is plotted in, on, and around a circle
representing the station. The following plotted station model shows where and how
various weather elements are reported. Use your textbook, page 722 to decode the
model and record the values for each aspect of weather listed below.
air temperature: ___________°F
dewpoint:___________°F
wind direction: ___________
wind speed: ____________knots
cloudiness: ____________%
precipitation/current
weather:____________________
air pressure: ___________mb
(To find the air pressure: first place a decimal between the second and third numbers
from the left. Then add a “9” or a “10” to the left so that the resulting number falls
between 960mb and 1050mb. For example, a plotted value of 126 represents 1012.6mb
and 863 means the pressure is 986.3mb. The SI unit for air pressure is the millibar,
abbreviated “mb”.)
2. Look at the Plot of Surface Station data for September 19, 1996. The map shows
weather conditions for a particular time on the 19th. A midlatitude storm system was
centered in the United States with fair weather conditions across the eastern third of the
US and mostly fair weather in the southwestern US.
At map time the conditions in DesMoines, Iowa (the model in central IA) were:
air temperature: ___________°F
wind direction: ___________
cloudiness: ____________%
weather:____________________
air pressure: ____________mb
dewpoint:___________°F
wind speed: ____________knots
precipitation/current
3. The reported air pressure at Grand Island, Nebraska (east central Nebraska where
winds were from the
west) was ___ than the stations immediately
surrounding it.
a. lower
b. higher
(circle one)
Although the cloud coverage at Grand Island was reported as clear, cloud conditions
at stations from South Dakota to Arkansas were generally ____. (note: an M within a
station model indicates the observation was missing.)
a. clear
b. cloudy
(circle one)
4. The wind pattern covering the several state area centering on eastern Nebraska was
generally __∆_
and _�__: This low pressure center of circulation was the
storm system mentioned in item #2.
∆
�
a. clockwise
a. inward
b. counterclockwise (circle one)
b. outward
(circle one)
5. Weather systems in the United States generally move from west to east. Comparing
the weather conditions from central Iowa to eastern Wyoming, DesMoines could expect
to experience __∆__ temperatures and _�__ weather as the system moves eastward.
∆
�
a. warmer
a. fair
b. cooler
b. stormy
(circle one)
(circle one)