Weather
a pilot can expect a windshear zone in a temperature inversion whenever the windspeed at 2000-4000 feet abovd the surface is at least 10 15 25
25knots
one of the most easily recognized discontinuities across a front is change in temperature an increase in cloud coverage an increase in relative humidity
a change in temperature
the suffix nimbus used in naming clouds mean a rain cloud a cloud with extensive vertical development a middle cloud containing ice pellets
a rain cloud
Possible mountain wave turbulence could be anticipated when winds of 40 knots or greater blow across a mountain ridge and the air is stable down a mountain valley and the air is unstable parallel to a mountain peak and the air is stable
across a mountain ridge and the air is stable
what types of fog depend upon wind in order to exist? radiation fog and ice fog steam fog and ground fog advection fog and upslope fog
advection fog and upslope fog
in which situation is advection fog most likely to form a warm moist air mass on the windward side of mountains an airmass moving inland from the coast in winter a light breeze blowing colder air out to sea
air mass moving inland front the coast in winter
the amount of water vapor which air can hold depends on the dew point air temp stability of the air
air temp
a temperature inversion would most likely result in which weather conditions? clouds with extensive vertical development above an inversion good visibility in the lower levels of the atmosphere and poor visibility above an inversion aloft an increase in temperature as altitude increased.
an increase in temperature as altitude is increased
where does wind shear occur? only at higher altitudes only at lower alititudes at all altitudes in all directions
at all altitudes in all directions
while operating around buildings the PIC should be aware of the creation of wind gusts that change rapidly in direction and speed causing turbulence increase performance of the aircraft enhance stability and imagery
change rapidly in direction and causing turbulence
If an unstable air mass is forced upward, what type clouds can be expected? stratus clouds with little vertical development stratus clouds with considerable turbulence clouds with considerable vertical development and associated turbulence
clouds with considerable vertical development and associated turbulence
what feature is normally associated with the cumulus stage of a thunder storm? roll cloud continuous updraft frequent lightning
continuous updraft
that are characteristics of a moist, unstable air mass? cumuliform clouds and showery precipitation poor visibility and smooth air stratiform clouds and showery precipitation
cumuliform clouds and showery precipitation
what clouds have the greatest turbulence towering cumulus cumulonimbus nimbostratus
cumulonimbus
during the life cycle of a thunderstorm, which stage is characterized predominately by downdrafts cumulus dissipating mature
dissipating
What are the processes by which moisture is added to unsaturated air? evaporation and sublimation heating and condensation supersaturation and evaporation
evaporation and sublimation
an airmass moving inland from the coast in winter is likely to result in rain fog frost
fog
if the temp/dew spread is small and decreasing and the temp is 62f what type of weather is mot likely to develop freezing precipitation thunderstorms fog or low levels clouds
fog or low level clouds
In which environment is aircraft structural ice most likely to have the highest accumulation rate? cumulus clouds with below freezing temps freezing drizzle freezing rain
freezing rain
the wind at 5000 agl is southwesterly while the surface wind is southerly=. this difference in direction is primarily due tot stronger pressure gradient at higher altitudes friction between the wind and the surface a stronger coriolis force at the surface
friction between the wind and the surface
the boundary between two different air masses is referred to as a frontolysis frontgenesis front
front
every physical process of weather is accompanied by or is the result of a movement of air pressure differential heat exchange
heat exchange
clouds are divided into four families according to their outward shape height range composition
height range
what conditions are necessary for the formation of thunderstorms high humidity, lifting force and unstable conditions high humidity, high temperature and cumulus clouds lifting force, moist air and extensive cloud cover
high humidity, lifting force and unstable conditions
when may hazardous wind shear be expected when stable air crosses a mountain barrier where it tends to flow in layers forming lenticular clouds in areas of low level temperature inversion frontal zone and clear air turbulence following frontal passage when stratocumulus clouds form indicating mechanical mixing
in areas of lowl level temperature inversion frontal zones and clear air turbulence
the presence of ice pellets at the surface is evidence that there are thunderstorms in the area has been cold frontal passage is a temperature inversion with freezing rain at a higher altitude
is a temperature inversion with freezing rain at a higher altitude
what measurement can be used to determine the stability of the atmosphere atmospheric pressure actual lapse rate surface temperature
lapse rate
an almond or lense-shaped cloud which appears stationary, but which may contain winds of 50knots or more is referred to as an inactive frontal cloud funnel cloud a lenticular cloud
lenticular cloud
which weather phenomenon is always associated with a thunder storm? lightning heavy rain hail
lightning
for aviation purposes, ceiling is defined as the height above the earths surface of the lowest reported obstruction and the highest layer of cloud reported as overcast lowest broken or overcast layer or vertical visibility into an obscuration lowest layer of clouds reported as scattered broken or thin
lowest broken or overcast layer or vertical visibility into an obscuration
thunderstorms reach their greatest intensity during the mature stage downdraft stage cumulus stage
mature stage
what are the characteristics of stable air good visibility and steady precipitation poor vis and stead precip poor vis and inter precip
por vis and steady precip
which weather phenomenon signals the beginning of the mature stage of a thunderstorm the appearance of an anvil top precipitation beginning to fall maximum growth rate of the clouds
precipitation beginning to fall
When warm, moist, stable air flows upslope, it produces stratus type clouds causes showers and thunderstorms develops convective turbulence
produces stratus type clouds
a stable air mass is most likely to have which characteristics showery precipitation turbulent air smooth air
smooth air
which weather conditions should be expected beneath a low-level temperature inversion layer when the relative humidity is high smooth air, poor visibility, fog, haze and low clouds light wind shea, poor visibility haze and light rain turbulent air . poor visibility , fog, low stratus type clouds and showery precipitation
smooth air, poor visibility, fog , haze and low clouds
A nonfrontal, narrow band of active thunderstorms that often develop ahead of a cold front is a known as a prefrontal system squall line dry line
squall line
thunderstorms which generally produce the most intense hazard to aircraft are squall line thunderstorms steady state thunderstorms warm front thunderstorms
squall line thunderstorms
what feature is associated with a temperature inversion? a stable layer of air an unstable layer of air chinook winds on mountain slopes
stable layer of air
crests of standing mountain waves may be marked by stationary, lens shaped clouds known as mammatocumulus clouds standing lenticular clouds roll clouds
standing lenticular clouds
low level turbulence can occur and icing can become hazardous in which type of fog? rain induced fog upslope fog steam fog
steam fog
what is a characteristic of stable air? stratiform clouds unlimited visibility cumulus clouds
stratiform clouds
steady precipitation preceding a front is an indication of stratiform clouds with moderate turbulence cumuliform clouds with little or no turbulence stratiform clouds with little or no turbulence
stratiform clouds with little or no turbulence
what is meant by the term dew point the temperature at which condensation and evaporation are equal the temperature at which dew will always form the temperature to which air must be cooled to become saturdated
temp at which air must be cooled to become saturated
the most frequent type of ground or surface based temperature inversion is that which is produced by terrestrial radiation on a clear relatively still night warm air being lifted rapidly aloft in the vicinity of mountainous terrain the movement of colder air under warm air or the movement of warm air over cold air
terrestrial radiation on a clear relatively still night
which condition result in the formation of frost? the temperature of the collecting surface is at or below freezing when small droplets of moisture fall on the surface the temperature of the collecting surface is at or below the dew point of the adjacent air and the dew point is below freezing the temperature of the surrounding air is at or below freezing when small drops of moisture fall on the collecting surface
the temperature of the collecting surface is at or below the dew point of the adjacent air and the dew point is below freezing.
what cloud type would indicate convective turbulence? cirrus clouds nimbo stratus towering cumulus clouds
towering cumulus clouds.
what are the characteristics of unstable air turbulence and good surface visibility turbulence and poor surface visibility nimbostratus clouds and good surface visibility
turbulence and good surface visibility
what are characteristics of a moist unstable air mass turbulence and showery precipitation poor visibility and smooth air haze and smoke
turbulence and showery precipitation
what causes variation in altimeter settings between weather reporting points? unequal heating of the earths surface variation of terrain elevation coriolis force
unequal heating of the earth surface
the conditions necessary for the formation of cumulonimbus clouds are a lifting action and unstable air containing an excess of condensation nuclei unstable, moist air either stable or unstable air
unstable moist air
one in flight condition necessary for structural icing to form is small temperature/dewpoint spread stratiform clouds visible moisture
visible moisture
what situation is most conducive to the formation of radiation fog warm moist air over low flatland areas on clear calm nights moist tropical air moving over cold offshore water the movement of cold air over much warmer water.
warm moist air over low flatland areas on clear calm nights
what would decrease the stability of an airmass? warming from below cooling from below decrease in water vapor
warming from below
cloud, fog or dew will always form when water vapor condenses water vapor is present relative humidity reaches 100%
water vapor condenses
one weather phenomenon which will always occur when flying across a front is a change in the wind direction type of precip stability of air mass
wind direction
if there is thunder storm activity in the vicinity of an anirpor at which you plan to land, which hazardous atmospheric phenomenon might be expected on the landing approach ? precipitation static wind shear turbulence steady rain
wind shear turbulence