CHAPTER 20WEATHER

20.2 Fronts and Lows

12/4 DAILY QUIZ

• 1. What is an air mass? • 2. Give the characteristics of each air mass

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20.2 Fronts and LowsSection 20.2 - Agenda

• What is a Front?• Types of Fronts

- Warm- Cold- Stationary- Occluded

• Life cycle of a Mid-Latitude Low

What is a Front?• The boundary that separates different air masses.

• Usually bring:1.Changes in Temperature2.Changes in Wind Direction

3.Changes in Humidity4.Precipitation

FRONT

•Advancing Cold Air•Forces Warm air up at a Steep slope•Usually a narrow band of precipitation•Cumulonimbus Clouds

1. Cold Front

Cold

Warm

Air

COLD FRONT

•Advancing Warm Air•Warm air rides over cold air at a low slope•Usually a wide band of precipitation•Brings thinner, layered clouds

2. Warm Front

Warm Air

Cold AirVis 2002

WARM FRONT

3. Occluded Front

•Cold Front catches up to Warm Front since cold fronts move twice as fast.

•Warm air is squeezed up, forming clouds.

4. Stationary Front

•Front is not moving.

•Warm air still rises above cold air, bringing clouds and precipitation.

•Can lead to flooding.

Life Cycle of a

Mid-Latitude Low

•Fronts are usually connected to Low Pressure systems.

•As the Low spins, the fronts move and the Cold front catches up to Warm.

•Takes 12 to 24 hours to get to stage 3.

Upper Air FlowUpper Air Flow steers the Low along

Weather associated with Pressure Systems

As a Low moves near, the weather will change. A

BC

EARTH SCIE

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SATURDAY STUDY G

ROUP

9am to

12noon

LAST PORTFOLIO

DECEMBER 17, 2012

TITLE: Name:

BIG IDEA

OTHER THINGS I COULD ALSO

KNOW

THINGS I HAVE TO KNOW TO UNDERSTAND THE BIG IDEA

Stamp Homework

Tonight’s Homework

FINISH WORK STARTED IN CLASS

Read Section 19-1, 19-2

Answer Section Assessment 19-2 & 19-2

Answer Worksheets 19-1 & 19-2

Complete Chapter 19.1.19.2 Powerpoint Notes

Daily Quiz

Worksheet 19-4 and 19-4

11/16 TODAY…