### weather | wind:

Summer wind
* are variable, with extended calm periods.
* can be a danger for small boats.
* help to cool off the hot, humid days and nights.

### weather | wind:

Thermal
* Most thermals span the boundary layer vertically.
* also tilt if the wind is stronger at higher altitude, the usual case.
* are a common source of low level turbulence for aircraft
  - bands of warmer air raising
* are columns of heated air rising above certain ground areas
  - spontaneously rising dry air
  - gas stations in the sky
  - most noticeable in mountains, but they waft around anywhere the terrain rolls and dips
  - parcels of continuously rising air
  - quite small near the ground but fan out and become larger as they rise
  - updrafts of air that hawks use to gain altitude
  - vertical convective currents that result from local heating
* can carry hawks and eagles very high in the sky.
* evolve over time, are influenced by terrain, and are shaped by and move with the wind.
* form as the sun heats the earth, and the air near the surface warms and expands
  - surface air is cooled due to a sea breeze, forcing the warm air aloft
  - downwind of a lake
  - due to a convergence of cool air and warm air
* is wind

### weather | wind | thermal:

Thermal biofeedback
* allows a patient to consciously raise hand temperature.
* provides information about skin temperatures.

### weather | wind:

Trade wind
* are semi-offshore in the main surf area of the north shore
  - very consistent westward winds near the equator
* blow hurricanes westward.
* drive the north and south equatorial currents.
* ensure year-round subtropical weather.
* force the moist ocean air up and over the islands' mass.
* help to cool the island and reduce humidity.
* is located in sea
* keep humidity low and Caribbean currents keep waters warm.
* make even the hottest days of the year tolerable.
* pick up great amounts of water vapor as they blow across the Pacific Ocean.
* prevail from the east and the monsoons come from the north-west.
* pushes surface water.
* pushes warm surface water
* reduce seasonal high temperatures.
* relax, sea level and sea-surface temperatures rise and the thermocline depth increases.

### weather | wind:

Updraft
* Most updrafts cause thunderstorms
  - occur at time
* Some updrafts are generated by heat.
* Some updrafts come from heat surfaces
  - land surfaces
  - occur in thunderstorms
* are drafts
  - found when a wind blowing at a hill or mountain has to rise to climb over the hill
* can recycle the droplets through the cloud, increasing droplet size.
* cause the cloud tops to grow higher and higher, sometimes as high as ten miles
* continue to feed warm humid air into the maturing storm cloud.
* dominate the circulation patterns within the cloud.
* indicate conditions.
* lead to convection.

### weather | wind | updraft:

Strong updraft
* Most strong updrafts occur at time.
* Some strong updrafts occur in thunderstorms.

Violent wind
* More violent winds are members of the hurricane family.
* Most violent wind carries fine particles
  - is accompanied by rain

### weather | wind:

Whistle
* Many whistles have the head glued or securely jammed into the barrel.
* Some whistles have a small ball bounces around inside the cavity.
* are devices
  - located in swimming pools
  - signals
  - sound
  - tonal in quality, like a high musical note or a dog whistle
  - very old instruments
  - wind instruments
* travel well at ground level due to their frequency and structure.
+ Recorder, History: Flutes
  * Whistles are very old instruments. People have found some whistles that were made in the Iron Age. A recorder is a type of whistle. It has holes for seven fingers and one thumb. It also has one end bigger than the other. The first recorders were made in the 1500s.