Weather Forecasting

Fronts A boundary between 2 air masses of different density, moisture, or temperature Represented on weather maps by various types of curving lines Cloudiness, precipitation and storms sometimes occur at frontal boundaries

Types of fronts Cold fronts Warm fronts Occluded fronts Stationary fronts

Cold fronts – draw picture Shown on a map as a blue line with triangles Occurs when colder air advances toward warm air Cold air wedges under warm air

Warm fronts – draw picture Shown on a map as a red line with semicircles Occurs when lighter, warmer air advances over heavier, colder air

When cold and warm fronts meet Warm air is lifted, it cools and water vapor condenses, forming clouds When the temperature difference between the cold and warm air is large or the cold front moves in quickly: Thunderstorms and even tornadoes may form

warm & cold fronts – draw pictures

Occluded fronts Involves 3 air masses of different temperatures: Colder air Cool air Warm air May form when a cold air mass moves toward cool air with warm air between the two The colder air forces the warm air upward, closing off the warm air from the surface Shown on maps as purple lines with triangles and semicircles

Occluded fronts- draw picture

Stationary fronts Occurs when a boundary between air masses stops advancing May remain in the same place for several days Producing light wind and precipitation Shown on maps as an alternating red and blue line Red semicircles point toward the cold air Blue triangles point toward the warm air

Stationary fronts – draw picture

Why does weather change? Air masses Air pressure Fronts

Severe Weather

Thunderstorms Heavy rain falls, lightning flashes, thunder roars, and hail might fall Occur in warm, moist air masses and along fronts Occur when warm air is lifted rapidly as cooler air sinks

Tornadoes A violently rotating column of air in contact with the ground Occur along fronts when cold fronts rapidly approach warm fronts

Hurricanes Read pages 610 – 611 Answer questions 3a and 3b

Extra Information A barometer is used to measure barometric pressure Maritime refers to water Continental refers to land The National Weather Service (NWS) is responsible for tracking hurricanes Satellite imagery has significantly improved in the last 20 years to help us have a better understanding of hurricanes The warmest part of a hurricane is the eye of the storm

Classwork 2/25 Complete weather forecasting worksheet Turn in when finished. If you do not finish in class, it is homework. If you finish before the bell rings, read a book or work on something from another class.

Classwork 2/26 You will work with a partner to complete the Coriolis worksheet. If you finish before we start to go over it, read a book or Scholastic magazine.