Reading a Station Model

from a Weather map

Cold Fronts & Warm Fronts

High and Low Pressure Systems

• Blue "H" = High pressure

HAPPY weather - Usually calm, sunny

• Red "L" = Low pressure

LOUSY weather - Can mean storminess

Air Temperature:

The number to the upper left of each station is the air temperature in degrees.

Fahrenheit (U.S. maps) or Celsius (Other countries)

Cloud Cover

- Each circle represents a weather station

- The circle at each station is empty if skies are clear

- The circle is white if it’s cloudy

- A line within the circle or a half-filled circle means "partly cloudy."

Wind and Wind Direction

• The little arrows attached to each weather station point in the direction the wind is blowing from

• The more barbs at the end of each arrow, and the longer they are, the harder the wind is blowing

• Each long barb is 10 knots (about 11.5 miles per hour or 18 kilometers per hour) • Each short barb is half that amount

• A barb that looks like a triangle is blowing at 50 knots (about 58 mph or 80 kph)

Dew Point The number to the lower left of each station is the dew point temperature in degrees.

Fahrenheit (U.S. maps) or Celsius (Other countries).

The dew point is a measure of moisture.

It shows how much you'd have to cool the air to get a relative humidity of 100 percent.

The higher the dew point, the more water vapor there is for producing rain or snow.

Barometric PressureThe number to the upper right of each station is the barometric pressure.

Since the pressure goes down with altitude, this reading has been adjusted toshow the pressure as if the station were at sea level.

The typical sea-level pressure is a little bit more than 1000 millibars.

How to Read & Write the Barometric Pressure

The number has been compressed to fit the map by lopping off the first one or two digits (which are always a "10" or a "9") and omitting the decimal point before the last digit.

For example:

• The code "085" would mean 1008.5 millibars.

• The code “954” would mean 995.4 millibars.

Steps:

1.Add the decimal point

2. Decide if you need to add a “10” or a “9”

• If the code starts with a 0, 1, 2, 3, 4, 5 then add “10”

• If the code starts with a 7, 8, 9 then add a “9”

The symbol highlighted in yellow indicates the type of weather occurring at the time the observation is taken.

In this case, fog was reported.

If there were thunderstorms occurring when the observation was taken, then the symbol for thunderstorms would have appeared instead.