Physical Geography Weather Exam 2 Study Terms Adiabatic effect Rising air expands and cools it holds less moisture as it cools which leads to condensation Cloud types note anything that begins with nimbo means rain Altocumulus Nimbostratus Normal stratus are the same just not filled with rain Fog Cirrus Cumulus Cumulonimbus Relative humidity The amount of moisture in the air compared to what the air can hold at that temperature Dew point the temperature below which the water vapor in a volume of humid air at a constant barometric pressure will condense into liquid water Condensation nuclei Neutral particles in the atmosphere that can absorb water and grow Basically begins condensation Most condensation nuclei come from the soil the ocean sea salt and the burning of vegetation and fossil fuels Lifting of air Frontal aka cold front Can create very bad weather including tornadoes Big pressure difference causes strong winds Also bigger storms if moving faster Convectional convergence thermal Orographic Cyclonic anticyclonic movement cyclonic high pressure anticyclonic low pressure Air masses c m T P A mP maritime polar cool humid unstable all year mT maritime tropical warm humid cT continental tropical hot low relative humidity dry A arctic super cold Frontal systems Cold front blue triangles Warm front red circles Occluded front when a cold front overcomes a warm front red circles and blue triangles on the same line sometimes shown purple Stationary front red circles and blue triangles on opposite sides of the line Reading WX maps The symbols will all be on the exam to know what the current weather wind speed and cloud cover are Tornadoes hurricanes Hurricanes An eye in the middle with spiral rain bands circling counterclockwise surface convergence and high altitude winds above Note Most hurricanes that start in the Atlantic are deflected by the Westerlies Tornadoes are extremely low pressure and come from cumulonimbus clouds and sometimes rarely cumulus Remember everything moves from high to low pressure when forecasting weather