Reading a weather map and weather instruments
Predicting Weather Vocabulary
 meteorologist
 air pressure
 humidity
 wind
 relative humidity
 barometer
 anemometer
 psychrometer
 rain gauge
 thermometer
Summary of Instruments used to collect
information:
 barometer: measures air pressure
 thermometer: measures temperature
 anemometer: measure wind speed
 wind vane: measure wind direction (all
winds must be in the same direction for
a hurricane to form)
 hygrometer: measures relative humidity
 pshychrometer: measures relative humidity
 rain gauge: measures precipitation
Precipitation
Rain Gauge
The rain gauge, measuring in
centimeters, collects ten times
the actual depth of rain that
falls.
Instruments to measure Humidity
Hygrometer
 Consists of a scale
with a strand of fiber
connected to a
pointer.
 This allows you to
read the relative
humidity inside
Sling Psychrometer
 Contains 2
thermometers: a wet
bulb and a dry bulb
 You use both bulb
temperatures to
figure out the relative
humidity
Relative Humidity
Relative Humidity
This chart shows how relative humidity changes with temperature.
Relative Humidity
Relative Humidity
Relative humidity is affected by temperature.
Air Pressure
Air Column
The weight of the column of air
above you puts pressure on you.
How does pressure from air
molecules keep you from being
crushed?
Air Pressure
Reading a Mercury Barometer
What would a low air pressure reading look like?
Air Pressure
Inside an Aneroid Barometer
An aneroid barometer has an
airtight metal chamber, shown
in red. Which diagram shows
the aneroid barometer under
high pressure and which shows
it under low pressure?
Air Pressure
Effect of Altitude on Pressure and Density
How densely packed would the molecules be at the different altitudes?
Air Pressure
 Air pressure is an air
flow, or wind around
a system that always
spirals around the
center of that area.
 High air pressure is
usually clockwise
flow of air in the NH
and counter
clockwise in the SH.
 Low air pressure is
always compensating
for the loss of mass
and goes counter
clockwise in the NH
and clockwise in the
SH
Reading Isobars for Measuring Air Pressure
 On a weather map, a
line connecting
points of equal air
pressure is called an
isobar.
 Remember, isobars
go in increments of 4.
Air Masses and Their Movements
Which circles are low-pressure centers and which are high-pressure
centers?
Winds
Wind Direction
and Speed
Based on the direction of
the wind vane, which
direction would the kite be
flying?
CAN YOU LABEL THIS MAP?
Predicting the Weather
Weather Map Symbols
The tables below show what various weather symbols represent.
Predicting the Weather
Newspaper
Weather Map
The symbols on this map
show fronts, highand low-pressure areas,
the
high and low
temperature readings for
different cities, and
precipitation. The color
bands indicate different
temperature ranges.
Predicting the Weather
Weather Map