aviation weather test 4

what is turbulence

irregular motion of an aircraft caused by convective currents (convective turbulence)

what are the three types of turbulence

convective, mechanical, and wind shear

convective turbulence is caused by

the rising and falling of air due to uneven heating

convective currents are most active on

warm afternoons when winds are light

to avoid turbulence, it is better to be

above clouds

mechanical turbulence

caused by obstructions of wind flow, such as trees, mountains, and buildings

winds increase as you go up in the

atmosphere

wind shear

sudden drastic change in wind speed or direction over a small area

temp inversion

strong wind shears often occur across temp inversion layers, which can generate turbulence

mountain waves

occurs when wind blows over a mountain and is forced to rise over a peak

after winds cross over a mountain it

oscillates or creates a series of waves on the downside (like waves in water)

main ingredients for a mountain wave to form

strong winds, stable air, wind direction

most severe winds events occur when

large scale winds are strongest (late autumn to early spring)

gravity waves

waves that form when air is distributed and gravity tires to pull the air back into its original position causing it to wave

kelvin Helmholtz waves

vertical waves in the atmosphere generated by wind shear

kelvin Helmholtz clouds are an indicator of

wind shear and can be associated with moderate turbulence

wave breaking

high above the ridge there is a region of updraft

trapped lee waves

form on the downwind (lee) side of a mountain when stable air flows over it

rotor

horizontal vortex that swirls beneath a larger airflow pattern

cap cloud

forms along the top of a mountain due to orographic lift

lenticular cloud

lens shaped cloud

what is the most common clue mountain waves are present

lenticular cloud

rodor clouds

MUST AVOID AT ALL TIMES

subtropical high-pressure belts

regions of persistent high atmospheric pressure found around 30 degrees in both hemispheres

northern hemisphere summer

lows form over land because land is warmer than water during the summer

northern hemisphere winter

lows form over water because water is warmer than land in winter

high pressure system rotates which direction in northern hemisphere

clockwise north counter south

monsoon

wind pattern that brings dynamic changes in weather, typically affecting tropical and subtropical regions

wet monsoon weather

low pressure in asia draws in moist unstable air

In the northern hemisphere high pressure moves

clockwise, low pressure moves counterclockwise

In the southern hemisphere

high pressure counterclockwise, low pressure clockwise

during the winter flying conditions are generally excellent over

dry interior regions

during the winter over water there are normally a lot of

showers and thunderstorms due to moisture

during the summer, showers and thunderstorms will be frequent over

land

transitory systems

transition zones btwn two different air masses

troughs and ridges are

elongated areas for high and low pressure

troughs and ridges are closely tied to

jet streams

tropical wave

elongated area of low pressure also known as inverted trough, that moves across the tropics

tropical cyclones are classified according to there

wind speed intensity

In order for a tropical cyclone to form you need

warm sea surface temp, minimal vertical winder shear, and a tropical wave

a hurricane is nothing but a

low-pressure system(no fronts attached)

the eye wall of a hurricane is

the strongest part or rain and winds

fog

a visible aggregate of minute water droplets that are based at the earth’s surface

fog differs from clouds because fog bases at

the surface

radiation fog

produced when the ground cools overnight after a clear calm day

in order for fog form you need

little to no cloud cover, light winds, sufficient moisture

advection/sea fog

forms primarily over sea

upslope fog appears on

the western side

frontal fog

occurs when warm air meets cold air at a front

steam fog

cold air lies over a much warmer water surface

freezing fog

temp is blw freezing and fog is present

what is more of a visibility problem fog or mist?

fog

haze

sunlight interacting with tiny little pollution particles

precipation is dependent on

temp

dust storm

severe weather condition characterized by strong winds and dust filled air 3000ft-6000ft normally

sandstorm

sand particles that are larger and heavier than dust particles

haboob

dust or sandstorm that forms as cold downdrafts from a thunderstorm turbulently lifts dust and sand into the air (NEED A THUNDERSTORM FOR THIS TO FORM)

volcanic ash

fine particles of rock powder that originate from a volcano

rime icing

rough, milky and opaque ice, forms at temps colder than -15c

clear icing

glossy, clear ice froms at temps warmer than -10c

mixed icing

rime and clear icing

super cooled liquid water content

how much water is available for icing