Overview of Weather Flashcards
What creates pressure? How do we map pressure? What is the relationship btw. pressure and weather? What causes low pressure/cyclones? What are fronts? What is the influence on mid latitude cyclones?
What creates weather?
Pressure
Define “PRESSURE”
- force exerted on an area of surface
- pressure is not the same everywhere-air moves from HIGH–>LOW
Define “ATMOSPHERIC PRESSURE”
- forces exerted by atmos. on Earth’s surface
- froce=due to weight of atoms.
What is the avg. sea level pressure?
101, 325 Pascals
How do you map pressure?
Isobars
- lines connecting points of equal pressure
- increase/decrease in increments of 4
What are the characteristics associated with HIGH PRESSURE?
- clear ski + dry
- anticyclone
- extreme temps
- air rises=Divergence
What are the characteristics associated with LOW PRESSURE?
- cloudy + wet
- Cyclone (storm)
- moderate temps
- aire rises=Convergence
What causes low pressure/cyclones?
-cold air from the polar region meeting warm air from the equator in the mid. latitudes
What is a “Tropical Cyclone”
- source of energy=warmth
- extreme weather
ex. hurricane
What is “Mid-Latitude Cyclone”
source of energy=warm air meeting cold air
=front
What is a “Mid-Latitude Cyclone” and what type of weather is it associated with?
- low pressure systems that form along fronts in the mid-latitudes (30^-60^)
- major weather producers of the mid. lats
- move West–>East
- clouds and moderate precip.–>storms with heavy precip.
What are FRONTS?
-narrow zone of transition (change) btw. air of different properties (usually temp)
Describe WARM Fronts
- warm air advances and replaces cold air
- gentle slope
- stratiform (layered) type clouds
Describe COLD Fronts
- cold air advances + replaces warm air
- steep slope
- cumuliform (puffy) clouds
- thunder storms
What is a “POLAR FRONT JET STREAM”?
-a narrow band of very fast westerly winds about 8-10km above earth’s surface in the mid-latitudes
