Weather Notes Fronts Part 5

FRONTS Cold Front Warm Front Stationary Front Occluded Front

What is a COLD Front? The area where a COLD air mass is replacing a warmer air mass. Symbolically, a cold front is represented by a solid line with triangles pointing the direction the front is moving.

Describe conditions associated with a cold front. Winds ahead of the cold front are generally from south-southwest, while behind the front, winds shift around and blow out of the west. As the colder air mass moves in the temperature drops Intense rain and thunderstorms may occur

Why do cold fronts cause intense storms? The cold air mass plows under and quickly lifts the warmer, less dense air There are strong upward motions that causes vertical (tall) clouds The slope of the cold front is very steep

Why does the temperature drop as a cold front passes? The cold air is replacing the warm air

What is a WARM Front? The area where a warm air mass is replacing a cold air mass. Symbolically, a warm front is represented by a solid line with half-circles pointing the direction the front is moving.

Describe conditions associated with a WARM front. As the front approaches wide spread clouds and light rain occur Winds ahead of the warm front are generally from the east, while behind the front, winds shift around and blow out of the south. The temperatures and the humidity rise

Why does the temperature increase as a warm front passes? The WARM air is replacing the COLD air.

What is an Occluded Front? When the air in the warm sector of a storm is lifted off the ground. Symbolically, an occluded front is represented by a solid line with alternating triangles and circles pointing the direction the front is moving.

Describe conditions associated with an occluded front. As the cold air mass pushes the warm, moist air up, light, moderate or heavy continuous precipitation or showers occur. The temperature falls.

Why does an occluded front cause light, moderate, or heavy precipitation? It is dependant on the relative temperatures of the air masses. The greater the difference the more intense the storms

Why does the temperature drop as an occluded front passes? The cold air is replacing the warm air.

What is a Stationary Front? When a warm or cold front stops moving, it becomes a stationary front. A stationary front is represented by alternating blue and red lines with blue triangles pointing towards the warmer air and red semicircles pointing towards the colder air.

Describe conditions associated with a stationary front. The weather is similar to that produced by a warm front except since the front doesn’t move or moves slowly there can be long periods of precipitation.

Describe conditions associated with a stationary front. cont A noticeable temperature change and/or shift in wind direction is commonly observed when crossing from one side of a stationary front to the other.