Forecasts

Unit 7 Day 5

Science Starter!1) How do air masses interact at a warm front

and what type of weather results?

2) How do air masses interact at a cold front and what type of weather results?

3) Hurricanes and tornadoes are what type of pressure system?

Agenda

• Warm Up & Objective• Wind & Station Model Basics• Forecast essentials: Interpreting symbols• Paired Weather Stations Activity• Weather Forecast Mapping Project• Exit Ticket• HW: Forecast Write-up

Objective

• SWBAT Explain and apply knowledge of weather symbols and data provided in maps and diagrams to predict the weather.

Wind

• Solar Energy = energy source for wind (unequal heating of Earth’s surface generates pressure differences)

• The Coriolis effect only influences the direction of the wind, not the speed.

Local vs. Global Winds

• Local: Influenced by topography (shape of land)

• Global Winds: large currents of winds that transfer heat from the poles and the equator (just like ocean currents!)

Winds

• Jet streams are fast moving “rivers” of air that flow at high altitudes

• Centers of low pressure=cyclones

• Centers of high pressure=anticyclones

Types of Global Winds• Trade Winds- Two belts of winds that blow

from the east.• Westerlies- Belts of wind blowing from the

west.**All weather in the US travels west to east**• Polar Easterlies- Winds that blow from the

polar high toward the subpolar low.

Weather Stations• Symbols used to determine several factors

including:1. Temperature2. Cloud Cover3. Dew Point4. Pressure5. Wind Speed (measured in knots/1 knot=1.15

mph) and Direction

HUMIDITYHumidity is the amount of water vapor in the air.

Measured in percentage of total water vapor the air

can hold.EX: 75% humidity means the air has

75% of the amount of water vapor it can hold

Wind Speed“Feathers” off the main line represent

wind speedHalf Feather = 5 mphFull Feather = 10 mph

EX: What is the wind speed in Utica, New

York? _______5 knots

10 knots

ATMOSPHERIC PRESSUREThis number is rounded to the

nearest 10th, with the leading 9 or

10 omitted.

1) Add a decimal2) Add a 9 or 10 in front of the

number3) Determine which is closest to

1000

ATMOSPHERIC PRESSURE

13813.8913.8 or

1013.81013.8

O

Baton Rouge, LAIn Baton Rouge, there was no cloud cover. The temperature was 70 degrees, with wind blowing from the south at 5 knots. There was 75 percent humidity with an atmospheric pressure of 998.4 mb. There was no previous weather.

Cloud cover: _____________________ Wind direction: ___________________Wind speed: _____________________ Temperature: ____________________Humidity: _______________________ Atmospheric Pressure: _____________Previous Weather: _______________

H and L 1) locate the observation station with the lowest

atmospheric pressure and write the word “Low” just above it.

2) The cold front comes out of the high-pressure center3) The warm front comes out of the low-pressure center

What weather is this location experiencing?

Cloud cover: _____________Wind direction: ___________________Wind speed: _____________________Temperature: ____________________Humidity: _______________________Atmospheric Pressure: _____________Previous Weather: _______________

Weather Station Wind Speed (mph)

Wind Direction Atmospheric Pressure (mb)

Temperature (oF)

Type of Weather Cloud Coverage (%)

Seattle 7 260o 1020.8 42 0Phoenix 11 50o 1021.1 45 0San Francisco 8 135o 1020.0 48 Fog 25Boston 12 100o 1018.1 52 Fog 25Colorado 24 225o 980 30o Snow 75Dallas 29 315o 1007.8 60 Hail 100Oklahoma City 45 315o 1007.8 57 Thunderstorms 100

Atlanta 20 120o 1032.3 56 Drizzle 50

Homework

• Find a weather map in the newspaper or on the internet. Use your knowledge to write a 1-paragragh description about the weather forecast and the influencing factors (e.g. air fronts, temperature, pressure systems, and wind).

Exit Ticket