2 Weather is....Weather is the day-to-day state of the atmosphere, and its short-term (minutes to weeks) variationWeather includes sunshine, rain, cloud cover, winds, hail, snow, sleet, freezing rain, flooding, blizzards, ice storms, thunderstorms, steady rains from a cold front or warm front, excessive heat, heat waves and more
3 Climate is....statistical weather information that describes the variation of weather at a given place for a specified intervalClimate may include precipitation, temperature, humidity, sunshine, wind velocity, phenomena such as fog, frost, and hail storms over a long period of time.
4 Weather vs. Climate in NC Monday morning:Sunny in the morning...Then becoming partly sunny. Highs in the lower 70s. East winds around 5 mphMonday evening:Partly cloudy. Lows in the upper 40s. Light and variable winds...Becoming east around 5 mph after midnight.ClimateNorth Carolina has a humid, subtropical climate. Winters are short and mild, while summers are usually very sultry; spring and fall are distinct and refreshing periods of transition. In most of North Carolina, temperatures rarely go above 100°F (38°C) or fall below 10°F (–12°C)
5 Main points to remember as we learn about weather: The sun warms the earth’s surface and therefore all the air above the surfaceThe earth is warmed most at the equator and least at the poles---why?The air above land is warmed more quickly than air above water.Warm air expands and rises, creating an area of low pressure; cold air is dense and sinks, creating an area of high pressure
6 Air Masslarge body of air that has similar temperature and humidity properties throughoutProperties of air masses, however are modified as they move over areas outside where they originateSource regions = regions where air masses develop their characteristics– need large areas with similar characteristic
7 Air Mass Classification Air masses have 4 major classificationsPolar (P)Tropical (T)continental (c) or maritime (m)Arctic (A) - extremely cold air masses
8 Air Mass Classification Air masses are classified according to their source regions:Warm and dry continental tropicalWarm and humid maritime tropicalCold and dry continental polarCold and humid maritime polarArcticAll five of these can be found in North America
9 Air MassesAir masses are masses of air that have the same characteristics of the surface over which it develops
10 Wind SystemsAir flows from areas of HIGH pressure to areas of LOW pressure; this creates windWinds are named for the direction from which they flow.Easterlies flow from the East to the West
11 Jet StreamA high altitude, narrow, westerly wind band that occurs above large temperature contrasts and can flow as fast as 185 km/h.
12 Coriolis Effect Caused by the Earth’s rotation Pulls the wind to the right in the northern hemispherePulls the wind to the left in the southern hemisphereStrongest at the PolesNone at the Equator
14 Air PressureWarm air= expanding or rising air= leaves behind L pressureCold Air=sinking air= leaves an area of H pressureAir Pressure/Atmospheric Pressure is measured with a barometer
15 Wind MovementUneven heating of the earth’s surface causes some areas to be warmer than others.As we know, warm always follows cold to share it’s warmth- when this happens in the atmosphere, wind happens!
16 What causes winds?A wind is a horizontal movement of air from a area of high pressure to an area of low pressureIt is this difference in pressure that makes the air move=windWinds are measured by direction and speedThe anemometer is the tool we use to measure thisWind chill=↑ cooling the wind causes
17 Local WindsThe land cools and heats faster than the ocean. Water holds heat longer than land, and takes longer to heat or cool.SEA BREEZEDuring the day, the land gets hotter faster than the water. The heated air rises, leaving behind an area of low pressure. Wind from the cooler sea blows in to take the place of that warmer air. These happen during the day!
18 Land BreezesAt night the lands cools off faster than the sea. Cool air sinks creating an area of high pressure. Wind blows from the land to the sea.