Transcript Air Masses
Fronts Interface (Boundary) between 2 air masses Colder air mass begins to wedge under the warmer air mass Fronts are always a sign of a change in the weather Fronts are always associated with LOW pressure On a weather map, fronts extend from the Center of the Low Low pressure L Warm front cP mT Cold front Cold Front cP air mass mT air mass • Cold air is MORE dense than warm air so cold air displaces warm air • Steep slope • Moves quickly • Showery precipitation (doesn’t last long) Conditions before a cold front • Warm humid • More ______________ southerly • Winds usually from ______________ direction • Pressure ____________ decreases Conditions after the cold front • cold drier • Air is more_____ North west • Winds usually from ______________ direction • Pressure ____________ increases Vertical clouds Cumulonimbus (thunderstorm) Towering Cumulus Cumulus Warm Front mT cP • Warm air is LESS dense than cooler air so warm air rises up and over the cool air • Gentle slope • Extended hours of precipitation Conditions before a warm front • cool easterly • Winds usually from ______________ direction Conditions after a warm front • warm southerly • Winds usually from ______________ direction High level clouds Cirrus Cirrostratus Cirrocumulus Mid-level clouds Altostratus Altocumulus Low-Level Clouds Stratus Nimbostratus Occluded Front • Faster, colder air overtakes slower, warm air • Warm air is forced up off the ground • Extended hours of precipitation Stationary Front • Neither air mass is moving • Cold and warm air • Precipitation similar to warm front cP mT COLD FRONT WARM FRONT