Frontal Weather By Diana L. Duckworth Rustburg High School Campbell County, VA

Fronts are the boundaries between air masses. Cold Front – cold, dense air pushes out warm air; polar air mass moves south. Warm Front – warm, low density air drags cold air out; tropical air mass moves north. Stationary Front – air masses stop moving Occluded Front – cold front overtakes a warm front and scoops warm air up – front is present only in upper atmosphere.

Cold Air Warm Air Sharp drop in air pressure, followed by clearing. Short, violent storms – Thunder & Lightning Tornadoes High winds, hail Heavy downpours Cold Front Weather Vertical development clouds – cumulus & cumulonimbus

Warm Air Cold Air Pressure gradually decreases then rises. Slow moving, covers 100’s of miles. Clouds gradually decrease in altitude; horizontal development. Rain or snow are steady; weather is not violent. cirrus Cirrocumulus, cirrostratus Altocumulus Altostratus Stratus; nimbostratus Warm Front Weather

Cold Front 2.Warm Front 3.Stationary Front 4.Occluded Front Front Symbols Triangles or hemispheres point in the direction its moving. Figure from Project Datastreme

Weather in Pressure Systems High Pressure (Anticyclone) –Clear Sky; Light Wind –Clockwise circulation, –Sinking air Low Pressure (Cyclones) - STORMS –Overcast; Precipitation –Counterclockwise circulation –rising air