Post on 24-Feb-2016
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Thunderstorms Form along low-pressure fronts Lightning - discharge of electricity from a
thundercloud Positive charge on top and bottom, negative in
the middle
THUNDERSTORMS AND LIGHTNING
They appear at the back of a thunderstorm For a tornado to form there must be a
rotating updraft called a mesocyclone. Mesocyclone is an updraft that occurs
when low winds are blowing at a different speed/direction than the winds higher up.
http://www.youtube.com/watch?v=I7MXHw_R4ps
TORNADOES
extends from Texas northward to North Dakota
Warm, moist air blows in from the Gulf of Mexico while cool, dry air blows in from the west higher up in the atmosphere, setting conditions for tornadoes to form.
Tornado Alley
STORM WATCHES AND WARNINGS
Storm Watch: If conditions are favorable for a severe storm or tornado to form a WATCH is issued.
Storm Warning: If a severe storm or tornado has been seen and is approaching a WARNING is issued.
HURRICANES Hundreds of kilometers wide. Have at least 119 km/h wind
Extreme low pressure center, gets energy from warm water between 5o and 20o of latitude
usually June through November. The strongest winds and rain occur in the
eye wall.
Hurricanes weaken as soon as they make land fall or move over cold ocean water.
Hurricanes that occur in the Atlantic Ocean north of the equator initially move to the west/northwest
Hurricanes
Hurricanes can cause tremendous amount of damage along the coast and inland. Storm surge results from the strong winds
of the eye wall which blows water into a broad dome.
Storm surge is what cause the massive destruction and deaths in New Orleans from Hurricane Katrina.
Hurricanes
Hurricanes Hurricanes are classified using the Saffir-Simpson
Hurricane Scale. All hurricanes start as tropical depression then become
tropical storms and eventually can become a hurricane. A hurricane can change categories many times during its
lifecycle depending on wind speeds. Hurricane Watches and Warnings
Watches are issued to communities that could see the hurricane arrive in the next 24-36 hours.
Warnings are issued to communities that could see the hurricane in less than 24 hours.