High Pressure vs. Low Pressure

H is for “HIGH PRESSURE” H is for HEAVY BLUE = COOLER Cool air contracts Cool air sinks because COOL air is HEAVIER Sunny but slightly cooler weather Heavy shoves clouds out of the way CLEAR SKIES Dry air Pressure increases which makes it heavier

L is for “LOW PRESSURE” L is for LIGHTER RED = WARMER Light air/low pressure expands Warm air rises because warm air is LIGHTER Often brings rainy/snowy weather Humid, moist air Pressure decreases which makes it lighter

Cold Front vs. Warm Front

COLD FRONT Looks like icicles Has air that is HEAVY A cold front has COLD(cooler), dry air behind it as it moves forward When a cold front meets a warm front, it shoves the warm front up higher Brings THUNDERSTORMS Pp. 600

WARM FRONT Looks like half suns A warm front has warmer, moist air behind it. When it moves over a cold front, it will rain near the frontal line where the rising air condenses. Pp. 600

HIGH PRESSURE Spins Clockwise No cloud cover Page 602 Pulls air down Cooler, Dry air Page 602

LOW PRESSURE Spins Counterclockwise Forms clouds Brings possible: Rise UP Forms clouds Warmer, moist air HUMID Brings possible: Tornadoes Hurricanes Page 602

COLD FRONT (pg 600)

WARM FRONT (pg 600)

Weather Forecasting Sample Forecast: Weather Channel: http://www.teachertube.com/viewVideo.php?video_id=164203 Weather Channel: http://www.weather.com/maps/maptype/currentweatherusnational/uscurrentweather_large.html