Weather Symbols
The Station Model
The weather of an individual weather station is plotted on
a station model.
The value highlighted in yellow
located in the upper left corner is
the temperature in degrees
Fahrenheit.
Temperature: is defined as a measure of the average of the speed
of the molecules in motion in the air.
- fast the molecules = high temperatures
- slow molecules = low temperatues
Weather Symbol
The weather symbol indicates the type of weather occurring at the
time the observation is taken.
Dew Point Temperature
Indicates the amount of moisture in the air
The higher the dew points, the higher the moisture content in the air.
Dew point = the temperature to which the air would have to cool in order to reach
saturation.
Saturation = When the dew point temperature and air temperature are equal. You can
tell if air is saturated by the formation of water droplets (drops on a glass).
Dew point temperature is NEVER GREATER than the air temperature.
What do you think happens when the temperature equals the dew point?
Formation of droplets of water, fog, or precipitation.
Cloud Cover
Air Pressure
The value highlighted in yellow represents the
last three digits of the observed pressure
reading in millibars (mb).
Interpreting Pressure Reports:
If reported value greater than 500:
Initial 9 is missing. Place it on left, then divide by 10 (add
a decimal point in between the last two numbers).
For example: 827 becomes 982.7 mb.
If reported value less than 500:
Initial 10 is missing. Place it on left, then divide by 10 (add a
decimal point in between the last two numbers).
For example (as in above diagram): 027 becomes 1002.7 mb.
Wind barbs point in the
direction "from" which the
wind is blowing. In the case
of the diagram to the right,
the orientation of the wind
barb indicates winds from
the Northeast.
Wind speed is given here in the units of
"knots". A "Knot" is a nautical mile per hour.
1 Knot = 1.15 Miles Per Hour (MPH)
1 Knot = 1.9 Kilometers Per Hour (KM/HR)
Each short barb represents 5 knots, each long barb 10 knots. A long
barb and a short barb is 15 knots, simply by adding the value of each
barb together (10 knots + 5 knots = 15 knots). If only a station circle
is plotted, the winds are calm.