Download Notes: Weather Maps How do you read weather symbols? This

Notes: Weather Maps
How do you read weather symbols?
This funny looking thing is a WEATHER SYMBOL. It represents data recorded from a _WEATHER
STATION.
The _CIRCLE is _CLOUD COVER.
The _ “TAIL” is the wind _DIRECTION. It shows where the wind comes FROM.
The _FEATHERS_ are the wind __SPEED_in knots. (1 knot = 1.15 miles)
½ feather = 5 knots
1 feather = 10 knots
1 triangle = 50 knots
What is the percent cloud cover at the station?
0%
What is the wind speed in knots?
15 knots
What direction is the wind coming FROM?
NNE or NE
What direction is it going to?
SSW or SW
•1) Draw a weather symbol with
–½ cloud cover
–wind at 5 knots out of the northeast.
•2) Draw a weather symbol with
–60% cloud cover
–wind out of the west at 55 knots.
What is a weather system?
•Remember the rule of thumb.
•Wind flows from areas of _HIGH_to __LOW__pressure!
•Air _PRESSURE__is equal to the _ WEIGHT of a column of _AIR_at a particular location. It is measured in
millibars (mb)
•_HIGH PRESSURE systems are regions of relatively _ high_pressure.
–**They are associated with _DRY _weather and _CLEAR__skies. Why?
- Air flows from high to low pressure. Air _SINKS_ and flows _AWAY from a
high pressure system. Therefore, few or no clouds form.
•_LOW pressure systems are areas of relatively _LOW______pressure.
****They are associated with clouds and precipitation. Why?
Air flows from high to low pressure. Air flows _TOWARD a low pressure system
and __RISES_________ Therefore, many clouds form.
What are fronts?
•An _AIR MASS is a large body of air with SIMILAR temperature, pressure, and humidity throughout.
•A _FRONT is a _BOUNDARY between air masses.
•We talk about “warm fronts” and “cold fronts.” These both happen with _LOW PRESSURE systems. Why
can’t they occur in high pressure systems?
Air flows from high to low pressure. Air __sinks and flows away from a high pressure system.
Therefore, few or no clouds form.
Cold Fronts
–A _cold_front is a boundary between an advancing _cold air mass and a warm air
mass that is already present.
–It is represented by triangles that point the direction the front is moving.
–Precipitation/clouds occur _BEHIND the front.
–Why?
•Cold air is __MORE dense and “pushes” the less dense warm air up.
Clouds form and precipitation occurs _BEHIND _the cold front. (I.e. it
gets cold before it rains).
Warm Fronts
A _WARM front is a boundary between an advancing _ WARM air mass and a cold air
mass that is already present.
It is represented by __SEMI-CIRCLES that point the direction the front is moving.
Precipitation/clouds occur _AHEAD OF the front.
Why?
•Warm air is _LESS DENSE and rises above the cold air. It condenses and
forms clouds _AHEAD OF THE front.
Warm Front
Cold Front
Brings cold air
Clouds and
precipitation behind
the front
Occurs during
a low
pressure system.
Brings
a
weathe
Brings warm air
Clouds and precipitation
ahead of the front