Thunder and lightning during a rain event. Heavy wind and rain and hail. Cloud type- cumulonimbus Warm humid air gets uplifted. Occur in midwest 60 days out of the year and south east 100 days.
What are the topologic feature that effect Thunderstorms?
Gulf of mexico-provide warm moist air.
Rockie Mountain-Block warm humid air from moving west.
Air Mass Thunderstorms
mT
Most common
Front pulls up mT air
Instability creates uplift
Seasonal-Land warmer>water summer and spring
Daily-Afternoon
Stages of a Air Mass Thunderstorm
1-Cumulus Clouds-Air rising (warm and humid air) Updraft-heated at surface due to land being warmer than waters where it originated.
2-Mature Stage-Updraft, precipitation forms and begins to fall creating downdrafts.
*Entrainment-creates void and surrounding air moves into cloud and with down drafts
*Once rain starts updrafts cut off, force down drafts to get stronger.
3-Dissipating Stage (End) Downdrafts
What is a sever thunderstorms?
58 mph wind
Hail-3/4 inches
Posisibility of tornados
Rapid Cooling
1) Air is not rising straight up: instead of sideways
2) Not all rain (downdrafts) cut off updrafts due to the angle of the updrafts.
3)Gust Fronts-downdrafts moving to the front of the storm front; build it outward; cold and windy
4)Forces updrafts to rise sooner and creates a developing cell.
5) Downdrafts lead to further development
What is a Squall Line?
Dry lines where strong thunderstorms occur 100-200 miles infront of the cold fronts.
What is supercell thunderstorm?
multiple storms combined; with air joining in, in different directions.
What is lightning?
First ice pellets
Second updrafts occur and downdrafts
Third movement of break ice pellets up and chargers moves to the top and a negitive charge to the bottom.
Fourth mini charge gets sent to charged grounds and then electricity travels downward.
What is thunder?
Lighning super heats air in a short period of time, creates thunder by creation of a sound wave.
What is a surface flow?
warm humid air
What is upper layer air?
Colder heavier air
What is unstable air?
Traps warm moist air on the surface.
What is a cold front?
Destroys capping layer, warm air burst up?
What is a tornado?
Uncertainty regarding development
Rotating column of air extending down from a cumulonimbus cloud.
Funnel vs. Tornado
Funnel-doesnt touch the ground
Tornado-Touches the ground
Rapid drop in pressure
Condensation and dark clouds
Invisible vs. dust and debris
Avg Diameter-500-2000ft
Avg Speed-30mph
Avg Wind Speed-72-300+mph
NE track
Can occur anytime of the year-more frequent during the spring and early summer.
Further north later in the seasons tornados occur
Tornado Classification
The Fujita Scale-Japanese scientist based on damage assement.
Intrainment
Heavy colder air that becomes part of the down drafts
Tornado related deaths
Decreasing in tornado related deaths
Increase in tornados being reported
This occurs because the increase in technology and warning systems.
Where is Tornado alley?
Texas, Oklahoma and Nebraska
Highest Wind Speeds ever recorded
318 mph highest wind speed-instraments was destroyed after recording.
Oklahoma City- only 3-5 people died
Tri-State Tornado
695 people killed
On the ground 219 miles
1925
Occured at night
What is a Tropical Cyclones?
Develop near equator(center of low pressure)
Power source warm water
80 F prime temp
Seasonality-late summer to fall
Most destructive natural disaster
Storm surge
High winds
Tornados
Lightning
Hurricane Formation
Need warm water
Do not form right on equator 5-20 N or S
Do not cross equator
No hurricanes on west coast
Hurricane Development
1-Tropical distrubances
T-Storms
Little pressure gradience
no rotation
2- Tropical or Easterly Wave
Ripple in the tradewinds
Piling up off warm, moist air-->low pressure
Pressure applied -->curved air flow
3-Low Wind Shear
Low level atmospheric winds or it will get destroyed
4-Divergence at the top
Allows pressure to lower
5-Many tropical disturbances: few develop further
Tropical depression 37>
Characteristics of a Hurricane
74< winds
Towering cumulonimbus clouds
Matual Hurricane= 350 miles in diameter
Significant pressure drop
Convergence at the surface and divergence at top
Strongest wind speeds on the right side
What is a steering wind?
Trade winds that determine where the hurricane goes
Right side- Hurricane winds and steering winds are in the same direction/combine, strongest winds and storm surge.
Left side- opposite direction
What is the anatomy of a hurricane?
Eye center- air is decending- cloud free, calm area
Eye wall- most intense rain, wind and most sever weather