Final_AAA

• •A
• storm containing lightning and thunder; convective storms
• •Ordinary
• Cell Thunderstorms
• –Air-mass
• thunderstorms: limited wind sheer
• –Stages:
• cumulus, mature, dissipating
• –Entrainment,
• downdraft, gust front
• •Severe
• thunderstorms (about 10% of thunderstorms):
• 1.hail
• 1 inch in diameter,
• 2.wind
• gusts greater than or equal to 50kts (58 mph), or
• 3.tornado
• 4.lightning
• not a criterion

Alot of them are near the equator.

Everywhere just not that frequently as in Florida

short life phenomeno nabouth 1 hour or so

• •Multi-cell
• Thunderstorms can develop:
• –Squall-line thunderstorms
• •line
• of multi-cell thunderstorms,
• •squall-line
• ahead of cold front
• •can
• create a derecho

• –Meso-scale
• Convective Complex:
• •a
• number of individual multi-cell thunderstorms grow in size and organize into a
• large circular convective weather system; summer, nearly 4,000 mi2 (red circle), or larger.

• 1.A
• number of convection cells,
• 2.Moderate
• to strong wind shear;
• 3.Tilt,
• over shooting top
• 4.Gust
• Front: leading edge of the cold air out-flowing air; shelf cloud, roll cloud,
• outflow boundary
• 5.Micro-bursts:
• localized downdraft that hits the ground and spreads horizontally in a radial
• burst of wind

• A gust front is the leading edge of cool air rushing down and out from a thunderstorm. There are two main
• reasons why the air flows out of some thunderstoms so rapidly. The primary
• reason is the presence of relatively dry (low humidity) air in the lower
• atmosphere. This dry air causes some of the rain falling through it to
• evaporate, which cools the air. Since cool air sinks (just as warm air rises),
• this causes a down-rush of air that spreads out at the ground. The edge of this
• rapidly spreading cool pool of air is the gust front. The second reason is that
• the falling precipitation produces a drag on the air, forcing it downward. If
• the wind following the gust front is intense and damaging, the windstorm is
• known as a downburst.

• • Downbursts:
  • 1.At
  • least 2.5 miles in size
  • 2.Can
  • exceed 100 mph
  • 3.Can
  • occur with or without a thunderstorm.
  • 4.Peak
  • winds can last 5 to 20 minutes
  • 5.Can
  • cause EF-3 damage – overturn trains.
  
  
• • A downburst is a strong downdraft which causes damaging winds on or near the
  • ground.
  • The term "microburst" describes the size of the downburst.
• A comparison of a microburst and the larger macro burst shows that both can
• cause extreme winds.

• Derecho:
• Straight-line winds, that can be high speed; similar to tornado
• •
• produced by a cluster of severe thunderstorms acting together
• •75
• to 300 miles across
• •
• wind damage must extend at least 250 miles along the storm's path

• •Multi-cell Thunderstorms
• •Thunderstorms
• that contain:
• 1.a
• number of convection cells, each in a different stage of development,
• 2.moderate
• to strong wind shear;
• 3.tilt,
• overshooting top
• 4.Gust
• Front: leading edge of the cold air out-flowing air; shelf cloud, roll cloud,
• outflow boundary
• 5.Micro-bursts:
• localized downdraft that hits the ground and spreads horizontally in a radial
• burst of wind

• •Supercell
• thunderstorms:

• –Large, long-lasting thunderstorm with a
• single

rotating updraft

• –Strong vertical wind shear; outflow never
• undercuts updraft

–Cap and convective instability

–Rain free base, low-level jet

• –2,000
• to 3,000 per year

• –They
• are the most intense thunderstorms anywhere

• –Tops
• – 65,000 feet (about 20 km)

• –Cloud
• diameters 12 to 30 miles (20 to 50 km)

• –They
• account for most tornadoes, and nearly
• all severe tornadoes

• –Updrafts
• can range from 45 to 90 mph!

• –They
• create most of the large hail, even to grapefruit size

• TOTAL
• TOTALS INDEX TT = T850
• + Td850
• - 2T500
• It’s
• is a measure of how buoyant the air parcel is due to less dense, moist air in
• the lower levels and how also buoyant the air parcel is due to warm air at
• lower levels.

• SWEAT
• (Severe
• WEAther
• Threat)
• INDEX :
• 1.low
• level moisture
• 2.convective
• environment (via TT)
• 3.changes
• in wind speed and direction with height (low level and middle level jet).

• •Floods
• and Flash Floods
• –Flash
• floods rise rapidly with little or no advance warning; many times caused by
• stalled or slow thunderstorm
• –Large
• floods can be created by training of storm systems,
• –Great
• Flood of 1993

• Lightning
• occurs:

• 1.80%
• in-cloud (within) or cloud-to-cloud (between)

• 2.20%
• cloud-to-ground

• 3.31,000
• miles per sec (50,000 km per sec)

• 4.temperature
• of the stroke channel = 54,000 deg
• F (about 5 times hotter than the surface of the Sun.

• 5.a
• typical lightning stroke is about 3 miles long and about 1 inch in diameter

• 6.both
• electrical and heat energy

• 7.you
• don’t need to be directly underneath a thunderstorm to get hit by lightning
• (bolt from the blue)

• 1.1,100
• ft
• per sec (330 meters per sec)

• 2.5
• sec per mile (3 sec per kilometer)

• 3.temperature
• differences in atmosphere bend higher frequencies away from the surface leaves
• lower frequencies.

• 30
• – 30 rule: if you can hear thunder before counting to 30 sec, then go indoors
• for 30 minutes

• •Rapidly rotating column of air that blows
• around a small area of intense low pressure with a circulation that reaches the ground
• It has to touch the ground

• Oklahoma
• Colorado
• Texas

• Tornado Alley" is a region with the most common tornadoes, just east of the
• Rockies. The city with the most recorded tornadoes is Oklahoma City, Oklahoma,
• which also had the strongest winds ever measured
• Dixie Alley is a nickname sometimes given to areas of the southern United States that are particularly vulnerable to strong or violent tornadoes. This is distinct from the better known Tornado Alley.

• April
• May (Most in this month)
• June
• JUly

• 3-8 pm
• Most 5 pm

between 1-8 am

• •Tornado
• winds
• –Measurement
• based upon damage after storm or Doppler radar
• –For
• northeast approaching storms, winds strongest in the southeast of the storm,
• 220 kts
• maximum
• –Multi-vortex
• tornados

A multiple-vortex tornado is a tornado that contains several vortices rotating around, inside of, and as part of the main vortex. These multiple vortices are somewhat similar to eyewall mesovortices found in intense tropical cyclones. The only times multiple vortices may be visible are when the tornado is first forming or when condensation and debris is balanced enough so that subvortices are apparent without being obscured. They are responsible for most (if not all) cases where narrow arcs of extreme destruction lie right next to weak damage within tornado paths.

• •The
• Fujita Scale
• –Based
• upon the damage created by a storm
• –F0
• weakest, F5 strongest
• –Enhanced
• Fujita Scale

• Weak
• Tornadoes:
• (EF0 & EF1)

• -
• 62.9% of all tornadoes

• -
• < 5% of tornado deaths

• -
• Lifetime 1-10+ minutes

• -
• Winds < = 110 mph
• Strong
• Tornadoes:
• (EF2 & EF3)

• -
• 34.8% of all tornadoes

• -
• ~ 30% of tornado deaths

• -
• Lifetime 20+ minutes

• -
• Winds > 110 - 165 mph
• Violent
• Tornadoes:
• (EF4 & EF5)

• -
• 2.3% of all tornadoes

• -
• 70% of tornado deaths

• -
• Lifetime 60+ minutes

• -
• Winds > 166 mph

• This
• mobile home had rested unanchored on cinder blocks before a tornado completely
• destroyed the structure and killed its
• occupant with little damage elsewhere.

A tornado family is a series of tornadoes spawned by the same supercell.^[1] These families form a line of successive or parallel tornado paths and can cover a short span or a vast distance. Tornado families are sometimes mistaken as a single continuous tornado, especially prior to the 1970s. Sometimes the tornado tracks can overlap and expert analysis is necessary to determine whether or not damage was created by a family or a single tornado. In some cases, different tornadoes of a tornado family merge, making discerning whether an event was continuous or not even more difficult.

The tornadoes usually occur within the same day, or continue into the early morning hours of the succeeding day, and within the same region. Most definitions allow for a break in tornado activity (time elapsed from the end of last tornado to beginning of next tornado) of six hours. If tornado activity indeed resumes after such a lull, many definitions consider the event to be a new outbreak. A series of continuous or nearly continuous tornado outbreak days is a tornado outbreak sequence. Tornado outbreaks usually occur from March through June in the Great Plains of the United States and Canada, Midwestern United States, and Southeastern United States. Tornado outbreaks do occur during other times of the year and in other parts of the world, however.

• •Basic
• requirements are:
• 1.an
• intense thunderstorm,
• 2.conditional
• instability, and
• 3.strong
• vertical wind shear

A landspout, or dust-tube tornado, is a tornado not associated with a mesocyclone. The name stems from their characterization as a "fair weather waterspout on land". Waterspouts and landspouts share many defining characteristics, including relative weakness, short lifespan, and a small, smooth condensation funnel which often does not reach the surface. Landspouts also create a distinctively laminar cloud of dust when they make contact with the ground, due to their differing mechanics from true mesoform tornadoes. Though usually weaker than classic tornadoes, they can produce strong winds which could cause serious damage.

• ^•Rotating
• column of air that is connected to a cumuliform cloud over a large body of
• water
• ^•Tornadic
• waterspout

• •
• A storm that originates in the tropics.
• •
• Classified by its wind speed:

• Classification of Tropical Weather
• Systems
• 0 mph £wind < 23 mph Tropical disturbance
• 23mph £wind < 39 mph Tropical depression
• 39mph £wind < 74 mph Tropical storm (NAME)
• 74mph £wind Hurricane

• NOAA 2011 Atlantic Season May 19, 2011 Begins June 1 and ends November 30

  1. 12 - 18 Named Storms (18) 2. 6 - 10 Hurricanes (6) 3. 3 - 6 Category 3+ Storms - winds at least 111 mph (3)

North or South of the Equator

The Saffir–Simpson Hurricane Scale (SSHS), or the Saffir–Simpson Hurricane Wind Scale (SSHWS), classifies hurricanes — Western Hemisphere tropical cyclones that exceed the intensities of tropical depressions and tropical storms — into five categories distinguished by the intensities of their sustained winds. To be classified as a hurricane, a tropical cyclone must have maximum sustained winds of at least 74 mph (33 m/s; 64 kn; 119 km/h) (Category 1). The highest classification in the scale, Category 5, is reserved for storms with winds exceeding 155 mph (69 m/s; 135 kn; 249 km/h).

• Saffir–Simpson Hurricane Scale
  Category	Wind speed	Storm surge
  	mph (km/h) (kn)	ft (m)
  Five	≥ 156 (≥ 250) (≥ 136)	> 18 (> 5.5)
  Four	131–155 (210–249) (114–135)	13–18 (4.0–5.5)
  Three	111–130 (178–209) (96–113)	9–12 (2.7–3.7)
  Two	96–110 (154–177) (83–95)	6–8 (1.8–2.4)
  One	74–95 (119–153) (64–82)	4–5 (1.2–1.5)
  Additional classifications
  Tropical storm	39–73 (63–117) (35–63)	0–3 (0–0.9)
  Tropical depression	0–38 (0–62) (0–34)	0 (0)

A dropsonde is a weather reconnaissance device created by the National Center for Atmospheric Research (NCAR), designed to be dropped from an aircraft at altitude to more accurately measure (and therefore track) tropical storm conditions as the device falls to the surface. The dropsonde contains a GPS receiver, along with pressure, temperature, and humidity (PTH) sensors to capture atmospheric profiles and thermodynamic data. It typically relays these data to a computer in the aircraft by radio transmission. The device's descent is usually slowed by a parachute, allowing for more readings to be taken before it reaches the water beneath.

• 1.ITCZ
• generated thunderstorms

• 2.Easterly
• waves

3.Extratropically

• 1.
• Start with a trigger mechanism such as a cluster of thunderstorms

• a)Streamline
• analysis is used because of small pressure differences

• b)Waves
• develop in the NE tradewinds
• (windshear)

• c)Waves
• create areas of surface convergence

• d)Surface
• convergence leads to thunderstorms.

• a)extratropical
• systems in autumn
• b)cold
• fronts extend into tropics, resulting in….?

• 1. Sea-Surface Temperatures >=80^oF
• a) Fuel fro the fire
• b) The warmer the warte, the more energy fro the sun
• c) Temps<80^oF, not enogh moisture and heat for hurricanes
• 2. Depht of warm water 200ft or more deep
• a) Hurricane circulation causes upwelling
• b)Cold water can weaken the hurricane
• 3.Weak vertical wind shear
• a)Strong vertical wind shear can "rip" developing hurricane apart
• 4. Location must be at leat 5 or more degrees north or south of equator (because of the corriolis effect)

• 1.Large
• number of thunderstorms; not just one convective cell

• 2.Systems
• spiral inward toward low pressure, creating rainbands

• 3.Wind
• speeds and precipitation intensity increase toward center (eye), creating a
• ring of deep convective clouds called the eyewall.

• Strom Surge
• Heavy Rain
• High Winds

• 1.Storm
• Surge: two causes,
• three enhancements
• A.Onshore
• Wind Different for each side and center
• B.Barometric Effect
• C. Wave Height

Strong winds in the storm increase wave height

D. Tides

• New or full moon (moon is in line with the
• Earth and the Sun) create high tides allowing for widespread flooding

E. Coastline Shape

• Confinement
• can focus surge

• A.On
• order of 10 inches per day

• B.Hurricane
• Mitch (1998) killed nearly 20,000, mostly by flooding caused by rain

• C.Tropical
• Storm Allison (2001) delivered heavy rainfall (40 in), flooded 46,000 homes and
• business

• Conservation
• of Angular Momentum – must be the same at all points
• Angular
• Momentum = mass x radius x rotational velocity
• Per
• unit mass:
• Angular
• Momentum = radius x rotational velocity
• 1
• knot = 1 nautical mile (nm) per hour

• The
• stronger the wind, the more evaporation
• takes place from the ocean, the more energy is introduced into the hurricane.

• WISHE
• – Wind
• Induced
• Surface
• Heat
• Exchange

• 1)Cold
• air above thunderstorms creates unstable air aloft and large, Cb
• clouds (a).

• 2)Latent
• heat warms air at troposphere, higher pressure causes air to move outward.

• 3)Pressure
• at surface drops

• 4)Surface
• convergence