Bellwork 4/18 What is El Nino/La Nina? What are some effects of El Nino/La Nina? Could be weather related, biological, economical, health related, ect…

“A cold front will be passing through our area over the next couple of days” A phrase that you’ve probably heard on a weather report (or something similar).

Air masses Characteristics 1600 km (1000 mi.) or more across Large body of air 1600 km (1000 mi.) or more across Perhaps several kilometers thick Similar temperature at any given altitude Similar moisture at any given altitude Move and affect a large portion of a continent

A cold Canadian air mass

Source region – the area where an air mass acquires its properties Classification of an air mass Two criteria are used to classify air masses By the latitude of the source region Polar (P) Tropical (T) By the surface type at the source region Continental (c) Maritime (m)

Air masses are classified on the basis of their source region

Air masses Four basic types of air masses Continental polar (cP) Continental tropical (cT) Maritime polar (mP) Maritime tropical (mT)

Which air masses affect the U.S? cP and mT air masses are the most important air masses in North America Continental polar (cP) From northern Canada and interior of Alaska Winter – brings cold, dry air Summer – brings cool relief

Fronts Boundary that separates air masses of different densities Warmer, less dense air forced aloft Cooler, denser air acts as wedge

Types of Fronts Warm front Warm air replaces cooler air Shown on a map by a line with semicircles Slow rate of advance & small slope Light-to-moderate precipitation

Cold front Cold air replaces warm air Shown on a map by a line with triangles Advances faster than a warm front & has a steep slope Associated weather is more violent than a warm front Intensity of precipitation is greater Duration of precipitation is shorter

Stationary front Flow of air on both sides of the front is almost parallel to the line of the front Surface position of the front does not move

Occluded front Active cold front overtakes a warm front Cold air wedges the warm air upward Precipitation is associated with warm air being forced aloft

Remember… This is an “Idealized” explanation This is weather typical of various front types Weather may or may not conform to these descriptions/pictures

Whiteboard Questions

Describe the Pressure Gradient Force.

Predict where is the air near Utah going to move.

Which direction do cyclones rotate in the Northern Hemisphere?

Which direction do anticyclones rotate in the Northern Hemisphere?

Are cyclones associated with a High or Low pressure system?

Which direction is wind coming from at the weather station in Minnesota?

Draw an “L” on your whiteboard Draw an “L” on your whiteboard. Draw in arrows around the “L” to indicate where winds would be coming from.

Coriolis Effect deflects air the _____________ in the Northern Hemisphere.

Air is moving from Florida away from the equator Air is moving from Florida away from the equator. Which direction will it be deflected?

How does a change in global wind patterns create El Nino conditions?

Describe an effect that El Nino has on an area’s Economy, Public Health, or Ecology