Tornadoes

Question 1

What does a tornado need to form?

Answer 1

instability from mT air and wind shear

Question 2

Vortex

Answer 2

a region in a fluid in which the wind rotates around an axis line

-vortex of tornado does not need a straight line axis

Question 3

How and why does a vortex become more intense?

Answer 3

When the vortex gets stretched in the vertical direction (decreasing its horizontal extent) by wind because its vorticity increase to conserve angular momentum

Question 4

Torando Definition

Answer 4

a rapidly rotating column of air that is in contact both with the surface of the Earth and a cumulonimbus cloud

Question 5

Where do the most violent tornados come from?

Answer 5

Supercells

Question 6

Enhanced Fujita Scale

Answer 6

rates magnitude of tornadoes on a scale of 1-5 based on damage after tornado

Question 7

Pressure in a tornado

Answer 7

very low pressure at center and extreme pressure difference over a very short distance (huge PGF)

Question 8

Where do most tornadoes occur?

Answer 8

in the US east of the rockies

Question 9

Lifecycle of a supercell tornado

Answer 9

1. Mesocyclone- rotating updraft
2. Wall cloud forms by stretching of mesocyclone
3. Funnel cloud
4. Tornado
5. Rope like spinning around a curved axis, can lead to dissipation but can also cause tornado intensity to increase
6. mature stage, peak intensity, nearly vertical axis

Question 10

Tornadogenesis

Answer 10

the process by which a tornado forms

Question 11

Tornado Outbreak defintion

Answer 11

multiple tornadoes spawned by the same synoptic scale weather system

Question 12

When are there more tornadoes?

Answer 12

In the summer with warm mT air
-typically in southeastern states

Question 13

What feature on radar indicates that a tornado may form

Answer 13

a hook echo - indicates mature mesocyclone

Question 14

Waterspouts

Answer 14

intense forties that occur over warm water bodies

Question 15

What direction do tornadoes rotate in North America?

Answer 15

can rotate in both directions

Question 16

What clouds to tornadoes form from?

Answer 16

Cumulonimbus clouds

Question 17

What direction do tornadoes usually travel?

Answer 17

Northeastward

Question 18

Wall cloud

Answer 18

descent of mesocyclone below the LCL

Question 19

Where does a wall cloud form?

Answer 19

Where cool, humid air forms zones of precipitation is drawn into the updraft that feeds the main cloud

Question 20

Funnel Cloud

Answer 20

form when a narrow, rapid rotating vortex emerges from the base of a wall cloud, has not yet reached the ground

Question 21

Where do non-supercell tornadoes develop?

Answer 21

Where the outflow from septette storm downdrafts causes convergence

Question 22

Why do most tornados occur in North America

Answer 22

1. The continent covers a wide range of latitudes
2. The central portion is relatively flat & no major mountain ranges extends in the east-west direction allows for strong collision of air
3. cP and mT encounter each other frequently - also cT which plays a role in dry lines

Question 23

When do most tornadoes occur?

Answer 23

Spring- strong air mass contrasts
Afternoon and early evening

Question 24

What is most structural damage caused by?

Answer 24

Wind strength

Question 25

What are most fatalities caused by

Answer 25

flying debris

Question 26

Why does there appear to be an increase in tornado outbreaks?

Answer 26

1. Greater chance of tornadoes being observed
2. Population increase
3. Improved detection from Doppler radio

Question 27

What has the number of fatalities dropped?

Answer 27

1. Better construction
2. Better broadcasting networks
3. Better tech for predicting and tracking

Question 28

National Weather Service

Answer 28

responsible for issuing tornado warnings and watches

Question 29

Storm Prediction Center

Answer 29

responsible for monitoring weather across the nation and advising local offices where there is potential for sever weather

Question 30

What forces are on balance in a tornado?

Answer 30

PGF in balance with the centripetal force

Question 31

Downdraft created in the real flank

Answer 31

-has its own horizontal vorticity
-allows the vortex from the surface to connect with the mesocyclone
-strong suction pulling in air to the downdraft region (warm downdraft associated with strong suction, cold downdraft associated with weak suction and no tornado will form)

Question 32

What are the two ways to track tornadoes?

Answer 32

1. Simulations
2. Radar observations
   a. precipitation intensity
   b. radial velocity of precipitating meteors (the speed raindrops and hailstones are moving along the line of sight); this uses Doppler radar: by looking at the wavelength and the frequency of the light you can tell the speed - can confirm rotation if air that coming towards you is neighboring air that is moving away from you (red is moving away from you, green is moving towards you, blue is very low level surface winds)
   -when we make these observations, they are not looking at the tornado but the supercell; the tornado is out of the line of sight of the radar because of the curvature of the earth

Question 33

What direction does the storm move?

Answer 33

In the longest direction of the supercell

Question 34

Ways to take measurements

Answer 34

1. Vehicles with stations connected
2. Weather balloons
3. Doppler on wheels (radar dish connected to flatbed truck)

Question 35

What type of thunderstorms do waterspouts usually form

Answer 35

single cell thunderstorms

Question 36

How do dust devils form?

Answer 36

formed from the bottom up through convection in a temp field that has some variation