IN p 133 Explain the difference between the vocabulary words in each of the following sets: 1.air mass, front 2.Humidity, relative humidity 3.Relative humidity, dew point 4.Dew point, precipitation 5.Hurricane, tornado 6.Meteorologist, station model 7.Isobar, isotherm 8.Isobar, front

P1&4 Tues 5/10 p3&6 Wed 5/11 Return borrowed textbooks! Vocab quiz Fri 5/13 Any missing work from Ch 15 must be completed by Fri May 13! That’s me!

Cornell notes Thru pg 134 Weather notes

Weather is what is happening in the atmosphere over a few hours or days. Climate is the overall weather of an area. – Tropical, desert, Mediterranean, semi- arid, etc Weather vs climate

Who studies weather? Meteorologist-scientist who studies the weather.

What controls the weather? Short answer – The SUN! The sun heats up air masses at different rates. Air Mass - Body of air that is characterized by similar temperatures and amounts of moisture at any given altitude.

CLASSIFIED BY: WET or DRY (moisture) – Maritime – Wet (forms over bodies of water) – Continental - Dry (forms over land) WARM or COLD (temperatures) – Tropical - Warm (forms near equator) – Polar - Cold (forms near poles) Written with: maritime (m) or continental (c) – lower case- first and Tropical (T) or Polar (P) -upper case- second mT mP cT cP

WHAT ARE THE AIR MASSES FOR THE UNITED STATES?

High Pressure Vs Low Pressure High pressure areas=sinking air – As air sinks, it warms up. – Difficult for clouds to form-fair weather. Low pressure areas=rising air. – As air rises, it cools and the water vapor in it condenses. – Creates clouds and precipitation.

COLLISIONS OF AIR MASSES When two air masses collide, that boundary is called a FRONT. FOUR TYPES – Warm Front – Cold Front – Stationary Front – Occluded Front

The triangles or half circles show the direction the front is moving. The color shows the temperature

How do they name FRONTS? The type of front depends on both the direction in which the air mass is moving and the temperature of the air mass.

COLD FRONT Cold air and warm air are moving towards one another. The cold air mass forces up the warm air mass.

WARM FRONT A cold air mass is receding. Warm air slides over top of the cold air mass.

STATIONARY FRONT A front that is not moving. Cold air and warm air meet head to head. Stationary fronts can also produce significant weather and are often tied to flooding events

OCCLUDED FRONT Two cold air masses meet, forcing warmer air that is trapped between them up and away from the Earth’s surface.

Jet streams A jet stream is a narrow band of high-speed winds that blow in the upper troposphere. Forms at the boundary between a cold air mass and a warm air mass. Flow along the boundary. Push storms and other weather around.

What is severe weather? Most weather that occurs doesn’t change daily routines: school, work, sports, activities Some weather conditions stop normal routines and can cause severe amounts of damage to people, structures and animals.

Formation of a Thunderstorm Warm air is forced up over cold air. It cools, forming cumulonimbus clouds. Rain falls, and cools the air. Cool air drops/warm air is forced up suddenly creating winds.

Anatomy of a thunderstorm

Thunderstorm damage Heavy rainfall over a long period of time. Flash flooding Strong winds, hail

Lightning Lightning is a electrical current that flows between areas of opposite charge(either cloud to cloud or cloud to ground.

Lightning Lightning can reach temps of 30,000⁰C – more than 5 times the temperature of the surface of the sun!

Thunder Lightning superheats air as it passes through it. The air expands and rapidly cools and contracts. The collapsing air creates a sound we call thunder.

Tornados Some of the most violent thunderstorms produce tornados Wind at different heights blows in different directions at different speeds This creates a rotating column parallel to the ground Updraft from the storm tilts the column upward into the storm called a funnel cloud. If the funnel cloud comes into contact with the earth’s surface, it’s called a tornado.

Tornado formation

Tornados cause millions of dollars in structural damage every year

Hurricanes/typhoons The most powerful of all storms A large, swirling, low pressure system that forms over the warm waters of the ocean Called hurricanes when formed over the Atlantic, typhoons over the Pacific, and cyclones over the Indian ocean. Over the water, the storm gets energy from the warm, moist air rising from the waters Over land, the energy dissipates and the storm loses it’s power

Hurricane damage High winds, tornados, heavy rains can cause a severe amount of damage The biggest threat is to islands where there isn’t enough land for the storm to lose energy. Islands and coastlines sustain the most damage

Blizzards Severe storms that happen in winter The National weather Service classifies a winter storm as a blizzard in the winds are 56 km/hr, the temps are low and visibility is less than 400 m in falling or blowing snow and if it persists for more than 3 hrs.

1.What is the abbreviation for each type of air mass? a)Maritime polar b)Maritime tropical c)Continental polar d)Continental tropical 2. What type of air mass is usually over Las Vegas? out