12-16-14What is weather?

Do Now: 1. How do you define weather?2. How do you describe weather?3. List all possible ways the earth’s atmosphere is

heated. (p.127)

HW – R&H pp. 126-127, A&E #1-7

Weather variables- the details we use to describe weather.Temperature – average kinetic energy of molecules in

air.(thermometer)Air pressure- the weight of air pushing down on

earth’s surface (warm air=low pressure)(barometer)Wind – horizontal movement of air (blows from high to

low pressure (anemometer)Humidity- amt. of water vapor in air (hygrometer)Cloud cover- % of sky covered with clouds (eyes)Precipitation- rain, sleet, hail, or snow (rain guage)Storms- rain, blizzard, tornado, hurricane

12-17-14What causes wind?

Do Now: R&H pp. 128-129.1. What affect does temperature have on air

pressure and why?2. What affect does humidity have on air pressure

and why?3. As altitude increases, what happens to

temperature, air pressure and air density?

HW: R&H pp. 131-132, A&E #8-24

Wind- the horizontal movement of air.

Caused by uneven heating, causing changes in temperature.

Uneven temp. causes changes in air pressure, creating areas of higher and lower pressure.

Air or wind blows from regions of high pressure to regions of low pressure, *always named from where it comes.

* Can happen locally with land and sea breezes or globally with wind belts. The greater the pressure gradient the greater the wind speed. No change in pressure results in no wind.

Land and Sea Breeze animation

www.classzone.com/.webloc

12-18-13What is a wind belt?

Do Now:1. If the barometer is falling what kind of prediction would

you make (temp, humidity, cloud cover, chance of precipitation)?

2. What causes wind?3. Look at p.129. Use the top right Pressure chart and

convert 30.10 inches to millibars.

HW- R&H pp. 133-135, A&E# 25-35.

1-5-15What causes ocean currents?

Do Now: Get out reference tables. Redraw your wind belt diagram neatly and label all. 1. How does weather travel in the United States? 2. What is the jet stream? 3. Why do deserts form at 30 degrees latitude? 4. What instrument is used to measure wind? 5. What is a pressure gradient? 6. What causes ocean currents?

HW- Finish Castle learning, get weather data.

Ocean Currents

1-6-15How do clouds form?

Do Now:1. R&H p.138 and describe all the factors that affect

evaporation.

HW: Get weather readings, Study all weather for quiz tomorrow!

Humidity Temperature and Dew Point1. Humidity – water vapor in the airA. Absolute humidity – actually how much water vapor is

in the air in grams/m3B. Relative Humidity- the amount of water vapor the air is

holding compared to what it could hold at a specific temperature, expressed as a %. Warmer air can hold more water vapor than cool air.

2. Dew Point Temperature- the temp. at which air becomes saturated or full with water vapor, meaning R.H. is 100%. Directions on p.139 for determining dew point.

** If air temp. drops below the dew pt. water vapor will have to condense.

Steps to Cloud Formation

Clouds formWhere moist air Rises Expands and cools.

RAEC- rising air expands and cools.

Steps to Cloud Formation1. Rising humid air expands and cools (RAEC)2. When the air cools to the Dew Point temp. the

R.H. will become 100% meaning air is saturated.3. Condensation will now occur as long as there is

a condensation nuclei available (ex. Dust, smoke, pollution) as a surface for condensation to form on. A cloud is born.

4. Very fine cloud droplets will collide and become larger, eventually becoming too heavy to be supported by the cloud and will fall from the sky as precipitation.

Cloud Types

Cumulus- white, puffy, cotton ball, fair weather clouds.Stratus – long, thin clouds that cover large portions of the sky. Hard to differentiate where one cloud ends and another one starts.Alto- higher up in atmosphereCirro/Cirrus Very high up in atmosphere. Called mare’s tails and they predict rain is coming.Nimbo/Nimbus- thunderstorm version.

1-7-15How does precipitation form?

Do Now:1. What are the steps to cloud formaton?2. What does precipitation do for the atmosphere,

explain?

HW- Get weather readings, finish lab.

1-9-15Aim: What is a Station Model?Do Now: R&H pp. 152-154.1. What is a station model?2. How do you indicate wind direction and wind speed on a

station model?3. As the difference between the temperature and the dew

point increases at the surface, what happens to the altitude of the cloud base?

4. Get weather readings for today.

HW- Finish lab.

1-12-15Aim: How do we make a station model?

Do Now:Log on to weather.com and type in 11978 and

make a station model for this morning’s weather. Use R.T. p.13 and R.B. p.153 as a guide.

Hw. A&E p.142#36-60.

1-13-15What is an air mass and a front?

Do Now: 1. Make a station model of today’s weather.2. What types of conditions favor lightning formation?

HW- A&E p.142#36-60.R&H pp.144-146, A&E #61-69

Air Mass- a large parcel of air with similar conditions of temperature and humidity

throughout.An air mass takes on the qualities of the location

where it comes from called a source region.m-maritime- comes from the water and is humid.c-continental- comes from the land and is dry.T-tropical- comes from the equator and is warm.P-polar- comes from the higher latitudes and is

cold.A-arctic- comes from the poles and is very cold.Pick a lower case and an upper case letter to

describe an air mass based on it’s source region.

Air Mass Source Regions

Front- the leading(front) edge of an air massWarm front – the leading edge of a warm air mass.

Because warm air is low density it will slowly drift over air in front of it causing stratus cloud development

Warm Front characteristicsWarm fronts bring a long period of light

precipitation in front of the front followed by whatever characteristics the new air mass contains. They are slow moving.

Cold Front- the leading edge of a cold air mass.

Because the cold air is high density it moves quickly and pushes air in front of it up causing cumulus cloud development and can form a short period of heavy precipitation on or behind the cold front followed by whatever conditions the new air mass brings.

Stationary FrontWhere a warm air mass and a cold air mass

approach one another and brings rain for as long as the front stays in place. Usually the cold air will push the warm air out of the way eventually moving the front.

1-14-15What is an occluded front?

Do Now:1. What kind precipitation does a warm front bring

and where would I find it in relationship to the frontal surface?

2. What is a front and which air mass will always rise causing possible cloud development and precipitation?

3. How do winds travel in a low pressure cyclone?

HW- R&Hpp.147-150, A&E #70-77

Occluded Front- when a cold front catches up to a warm front in a cyclone and the two

combine. Produces very heavy precipitation.

High and Low Pressure Centersin the Northern Hemisphere

Cyclyones- areas of low pressure that are associated with warmer temperatures, high humidity, and possible storms. Winds circulate in a counterclockwise and inward spiral as a result of earth’s rotation. (Lousy Lows)

Anticyclones- areas of high pressure associated with cooler temperatures, low humidity and generally good weather. Winds circulate in a clockwise and outward spiral. (Happy Highs)

1-16-15What is a mid latitude cyclone?

Do Now- 1. List 3 things you can use from a station model to predict and how you would use them.2.Describe how an occluded front forms and what kind of weather it brings.3. Look at p.141, what is the difference between these different types of precipitation?

HW- Finish lab.

Mid-Latitude CyclonesForm as a result of converging cP air from the north

and mT air from the south. They start as converging air creating low pressure

cyclones.Cold fronts catch up to warm fronts and form

occuluded fronts which produce thunder cells.The low pressure cyclones spin counter clockwise and

inward and generally move to the northeast in the US.These storms can result in thunderstorms, hail storms,

tornadoes, hurricanes or blizzards.

Hurricanes,Tornadoes, BlizzardsHurricanes- low pressure cyclones forming in tropical

waters and growing to a massive size. Suck up tremendous amounts of water and create violent wind (74mph or more), heavy rain bands, and storm surge waves. Can last for a week or more and cause the most damage when making landfall. Go to high ground and under shelter.

Tornadoes- low pressure cyclones forming from a mid-latitude cyclone on land. Winds up to 300 mph are concentrated into a narrow funnel cloud which acts like a vacume cleaner. Last generally from a minute to an hour. Go underground if possible.

Blizzards- a storm with winds of 35 mph or better with tremendous amounts of snowfall.

1-10-12Topic 7 Review

Do Now:1. Why is it hot and humid at the equator,

whereas it is hot and dry at 30 deg. North and south?

2. Use the diagram on the board and make a 1,3, and 5 day prediction for location C.

HW- Study all of T.7 for exam tomorrow.