Transcript 27. Weather Part 8 – Fronts and Weather Maps

Fronts and Weather Maps
Consider This:
 Uneven heating of the Earth and Earth’s rotation
(Coriolis) help create:
 Winds
 Jet Stream
 Currents
 All are connected to high and low pressure systems.
Remember:
 High Pressure System:
 Air cools and falls
 More pressure from above
 At surface, air tries to move outward
towards low pressure
 Coriolis causes a clockwise wind flow
 Fair weather because relative
humidity is low.
Remember:
 Low Pressure System:
 Air warms and rises
 Less pressure
 High pressure tries to flow towards it
 Coriolis causes a counter-clockwise
wind flow
 Stormy weather because relative
humidity is high
High and Low Pressure
 Pressure Systems Explained
Air Masses
 A large portion of air that is nearly uniform in
temperature and humidity.
 Cold air masses will move towards warm air masses.
 Just like high pressure systems move towards low
pressure system.
Fronts
 Boundaries between air masses.
 Warm front
 Cold front
 Stationary front
 Storms typically develop at fronts.
Fronts
 Warm Air Front:
 Warm air is pushing cold air.
 But warm air is forced over top.
 Mild precipitation.
 But brings warmer temperatures.
Fronts
 Cold Fronts:
 Cold air pushes underneath warm air.
 So warm air rises.
 Severe precipitation.
 And brings cooler temperatures.
Fronts
 Fronts Explained
Isobars
 Lines of equal atmospheric pressure drawn on a
meteorological map.
Weather Maps
 High pressure – H
 Low pressure – L
 Warm fronts
 Cold fronts
 Stationary
Weather Maps
Weather Maps
 How to Read a Weather Map