Weather ©Mark Place, 2009-2010 www.LearnEarthScience.com

weather basics the uneven heating of the Earth’s surface Where does the energy for weather originate? the uneven heating of the Earth’s surface

In the US, the general direction that weather systems weather basics In the US, the general direction that weather systems move is toward the northeast

dewpoint are measured in Station Models Please go to page 13 of the ESRTs Temperature and dewpoint are measured in degrees _______ F

.. Cloud Cover Temperature 76 138 Wind Direction & Speed -30\ Current Weather 55 Dewpoint Barometric Trend Barometric Pressure

Station Model Practice

Evaporation Rates Relative Humidity Temperature Surface Area

What natural process cleans the atmosphere? Rain precipitation Snow Hail

Cloud Formation

Cools to the dewpoint Expands Warm Air Rises

Clouds are likely to form when: The air is saturated and rising The temperature is at the dewpoint Condensation nuclei are available

As air temperature increases the air can hold more water

lower due to evaporation Sling Psychrometer Dry bulb measures air temperature Wet bulb temp is lower due to evaporation

Using the charts on page 12 of the ESRTs, calculate the relative humidity and dew point using the following information. Dry Bulb Wet Bulb Difference Dew Point Relative Humidity (%) 14 10 4 20 5 30 19 18 56 6 60 15 12 58 23 7 55 13 5 9 Dewpoint Chart RH Chart

Relative Humidity vs Air Temperature Indirect Relationship as temp increases RH decreases

As dew point increases, the amount of moisture in the air

dewpoint get closer together, the probability of precipitation As temperature and dewpoint get closer together, the probability of precipitation INCREASES

probability of precipitation? Which has the greatest probability of precipitation?

Pressure and Wind ©Mark Place, 2009-2010 www.LearnEarthScience.com

What instrument is used to measure: wind speed air pressure anemometer barometer [ORIGIN from Greek anemos ‘wind’] [ORIGIN from Greek baros ‘weight’]

How are winds named? The direction from which they come

What causes wind? diferences in pressure

Which pressure gradient would result in greater wind velocity?

measurements using the chart Convert the following measurements using the chart on page 13 of the ESRTs. 29.73 997 30.18 994

Wind blows from areas of to areas of high pressure low pressure

Draw the relationship between air pressure and air density.

This is because the air is Therefore, clouds CANNOT form. In a high pressure area, air will (rise, sink) because the air is (less, more) dense. This is because the air is (cold, warm) and (rises, sinks). Therefore, clouds CANNOT form.

This is because the air is In a low pressure area, air will (rise, sink) because the air is (less, more) dense. This is because the air is (cold, warm) and (rises, sinks). Therefore, clouds are LIKELY to form.

Correctly draw the direction of wind flow around both a high and a low pressure area in the NORTHERN HEMISPHERE.

counterclockwise wind direction low pressure high pressure warm or cold air air rising or sinking clouds or no clouds clockwise or counterclockwise wind direction winds toward or away from the center warm cold rising sinking clouds no clouds counter clockwise clockwise toward away

On the diagrams below, label which one represents a land breeze and which represents a sea breeze. Correctly label on each diagram where the high and low pressure areas would be found.

Sea Breeze (daytime) H L On the diagrams below, label which one represents a land breeze and which represents a sea breeze. Correctly label on each diagram where the high and low pressure areas would be found. Sea Breeze (daytime) H L

Land Breeze (night time) L H On the diagrams below, label which one represents a land breeze and which represents a sea breeze. Correctly label on each diagram where the high and low pressure areas would be found. Land Breeze (night time) L H

What’s the relationship between wind and waves? direct (the stronger the wind, the bigger the waves)

45°N 45°S 75°N 20°N southwest northwest northeast northeast Using the chart on page 14, state the prevailing wind direction for each latitude below: 45°N 45°S 75°N 20°N southwest northwest northeast northeast

Is air rising or sinking at the equator?

Is air rising or sinking at 30°N?

©Mark Place, 2009-2010 www.LearnEarthScience.com Air Masses

AIR MASS What's the definition? A large body of air with similar characteristics throughout

Air masses are classified based on their and amount of temperature moisture

Air masses get their characteristics based on where they form

continental dry maritime moist Tropical warm Polar cold Arctic The abbreviations used to classify air masses use the following letters: c, m, T, P, and A. For each letter, describe its property: Word Means c m T P A continental dry maritime moist Tropical warm Polar cold Arctic very cold

What would their characteristics be? mT cP warm and moist cold and dry

High or Low Pressure? mT cP H L

What type of air mass would form over each area? Please label. cA mP mP cP cT mT mT mT

World Air Mass Source Regions

Animation #1 http://www.classzone.com/books/earth_science/terc/content/visualizations/es2001/es2001page01.cfm?chapter_no=20

cP air mass dry, cool air High Pressure Area mT air mass warm, moist air Low Pressure Center

cP air mass dry, cool air High Pressure Area mT air mass warm, moist air Low Pressure Center

cP air mass dry, cool air High Pressure Area mT air mass warm, moist air Low Pressure Center

cP air mass dry, cool air High Pressure Area mT air mass warm, moist air Low Pressure Center

cP air mass dry, cool air High Pressure Area mT air mass warm, moist air Low Pressure Center

Fronts ©Mark Place, 2009-2010 www.LearnEarthScience.com

a boundary (interface) FRONTS Please Go To Page 14 a boundary (interface) between air masses

The Rule: triangles and bumps always point in the direction the front is moving

a cold front moving south an occluded front a stationary front with cold air on the south side a warm front moving north a stationary front with warm air on the south side

Cold Fronts Animation #1 Images

Warm Fronts Animation #1 Images

PAGE 12

PAGE 13 COLD FRONTS: Using the Words below, complete the paragraph. 15 degrees, cold, cold, colder, colder, cooler, clouds, drier, hail, rain, thunderstroms, tornadoes, towering clouds form, warm, warmer Passage of a cold front: Cold fronts occur when a .............. air mass replaces a ................ air mass.  In a cold front the .............. air follows the warm air, and, because .................. air is denser, pushes ................ air out of its way, forcing the warm air to rise. The lifting warm air mass becomes ................, and ................. start to form. Precipitation at cold fronts are usually heavier although less extensive (50-70 km) and less prolonged. The reason for this is that the uplift of warm air there is stronger due to the undercutting of cold air, so......................................., and .........., ......................................, ................ and ............................ can occur. The air behind a cold front is noticeably .......................... and ................... than the air ahead of it. When the cold front passes through, temperatures can drop more than ........................... within the first hour.

PAGE 13 WARM FRONTS: Using the Words below, complete the paragraph air, cirrus clouds, cold, colder air mass, in front of them, lifts up, move slowly, settling over the cold front, warm, warmer, warmer and more humid Warm fronts: Warm fronts occur, when a ......................air mass approaches a ............................... The warmer air ....................... and over the colder air. .................fronts are usually more gentle than ..............fronts, ................................, gently ..................................................and moving it out of the way. Precipitation at warm fronts are usually less heavy although more extensive (300- 400 km), than at the cold fronts. The .................behind a warm front is warmer and more moist than the air ahead of it. Warm fronts bring more steady, lighter rain or snow ………………………, which can last from a few hours to several days. When a warm front passes through, the air becomes noticeably ...................................than it was before. The first signs of the warm front are the ..........................., followed by the cirrostratus, altostratus, nimbocumulus and stratocumulus types of clouds.

Animation PAGE 12

Hurricanes Lightning Tornadoes ©Mark Place, 2009-2010 www.LearnEarthScience.com

Footage

Tornado Footage http://www.stormstock.com/storm_cloud_footage.html http://www.ultimatechase.com/Tornado_Video.htm

Lightning Footage http://www.stormstock.com/lightning_footage.html http://www.ultimatechase.com/Lightning_Video.htm