FUN WEATHER WOOOOOOOOO Flashcards
characteristics of low pressure air
movement inwards, upward, and counterclockwise
characteristics of high pressure air
movement outward, downward, and clockwise
what weather can you expect in a low pressure area
rising air which conducts cloudiness, precipitation, and bad weather
what weather can you expect in a high pressure area
descending air which favors dissipation of clouds and good weather
cold front definition
a mass of cold, dense, and stable air replaces a body of warmer air
warm front
a mass of warm air overtakes a body of cold air
occluded front
when a fast moving cold front catches up with a slow-moving warm front
stationery front
forces of 2 air masses are relatively equal, the boundary that separates them remains stationary. weather is a mixture of both a warm and cold front
characteristics of a cold front
cumulus/cumulonimbus clouds, better visibility (when no rain), variable/gusting winds, unstable air, dew/temp point and barometric pressure drop rapidly
characteristics of a warm front
stratiform clouds, poor visibility, stable air
what is a trough
an elongated area of relatively low pressure
how does air flow in a trough
since it cannot go down or out, it must go up, meaning rising air
what is a ridge
an elongated area of relatively high pressure
how does air flow in a ridge
the air moving out depletes the quantity of air, creating areas of descending air
standard temp and pressure values
15 C/59 F and 29.92” Hg or 1013.2 millibars
what are isobars
line on a weather chart that connects areas of equal or constant barometric pressure
what do the spacing of isobars show
how steep or shallow the pressure gradient is
what does it mean when isobars are very spaced out
a shallow pressure gradient and less wind speed
what does it mean when isobars are spaced very closely
a steep pressure gradient and higher wind speed
name of the force of wind that deflects wind to the right in the northern hemisphere and left in the southern
Coriolis force - at a right angle to wind direction and is directly proportional to wind speed
why do surface winds generally flow across the isobars at an angle
surface friction
atmospheric pressure lapse rate
1” Hg per 1000 ft
what is dew point
temp at which a sample of air must be cooled gain a state of saturation
what weather is likely when temperature and dew point are close (within 5 C)
visible moisture like clouds, dew, or fog. Ideal conditions for carb icing
what factor primarily determines type and vertical extent of clouds
the stability of the atmosphere
what is a stable atmosphere
a stable atmosphere makes vertical movement difficult and small vertical disturbances dampen and disappear
what is an unstable atmosphere
small, vertical air movements become larger, resulting in turbulent airflow and convective activity
effects of stable air
clouds - stratiform, turbulence - small/smooth, precipitation - steady, visibility - ok/poor
effects of unstable air
what clouds, turblence, precipitation, and visibility
clouds - cumuliform, turbulence - rough, precipitation - showery, visibility - good
when significant precipitation is occurring at the surface, how thick can you expect the clouds to be
at least 4,000. the heavier the precipitation, the thicker the clouds are likely
important meteorological information to take during preflight planning
location of fronts, cloud layers, freezing levels, and air temp and pressure
definition of freezing level
lowest altitude over a given location at which the air temp reaches 0 C.
how can you determine where freezing level is (10)
current icing products (CIP), forecast icing products (FIP), freezing level graphic chart, as well as GFAs, PIREPs, AIRMETs, SIGMETs, surface analysis charts, low-level significant weather charts, and winds and temp aloft
conditions necessary for structural icing to occur
visible moisture and below freezing temperatures at the point the moisture hits the aircraft
2 main categories of aircraft icing
structural icing and induction icing
what is structural icing
ice that forms on aircraft surfaces and components
what is induction icing
ice that forms in the engines induction system
3 types of structural icing
clear, rime, and mixed ice
what is clear ice
ice that forms after impact when remaining liquid flows over the aircraft surface and freezes as a smooth sheet
what is rime ice
the liquid portion remaining after initial impact freezes rapidly before the drop spreads
what is mixed ice
drops vary in size and ice particles become imbedded in clear ice building rough accumulation
what action is recommended if you encounter icing
leave area of visible moisture either by climbing or turning to a different course
is frost considered hazardous
yes