Severe Weather

How to Read a Weather MapUnit 11 – Day 2

Warm and Cold Fronts

• Blue lines are cold fronts and red lines are warm fronts.

• High and Low Pressure Systems–A _________ means a center of high

pressure (usually calm, sunny weather). –A red "L" means low pressure (which can

mean storminess). Most fronts extend from low-pressure centers.

How would you read the cold

and warm fronts on this map?

In which directions are they going?

Weather Station SymbolsCloud CoverEach circle represents a weather

station. The circle at each station

isempty if skies are clear. The circle

iswhite if it’s cloudy. A line within

thecircle 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. Each

short barb is half that amount.

Weather Station Symbols Air Temperature The number to the upper left of each station is the air temperature in degrees F (for U.S. maps) or degrees C (for other countries).

Dew Point

The number to the lower left of each station is the dew point temperature in degrees F (for U.S. maps) or degrees C (for 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.

Weather Station Symbols

Barometric Pressure• The number to the upper right of

each station is the barometric pressure.

• Standard air pressure is 1013mb. (14.7lb/sq. in.)

http://eo.ucar.edu/webweather/