Met (See Met Revision Too Multi Eng) Flashcards
Specific heat capacity
Ability of a material to hold thermal/heat energy
3 factors that affect earths surface temp
Latitude, season and time of day
What is Total air temp (TAT)
Product of SAT (which is basically OAT) and ram rise (compression of air on probe)
What is the SALR
Temp change for a saturated air particle when cooled to its dew points, 1.5deg/1000ft
4 main groups of cloud
Curriform, cumiliform, stratiform, nimbus
3 layers of cloud and their bases
Low level = below 6500ft
Alto (med) level = greater than 6500ft
Cirro (high) level = greater than 16500 to 20000ft
How do lenticular clouds form
When orographic uplift causes air to rise and cool adiabatically and once cooled, produces cloud
Different stability of air type effect on lenticular clouds
Stable air = lenticular on hillside
Unstable air = cumulus or CBs
How does radiation fog form and what is needed
When no cloud at night so ground cools air above and it condenses
Need moist air and wind below 8kt
What 2 things does Virga show
Inversion and potential WS
Height of instability needed for thunderstorm
ELR has to be greater than SALR, and over 10000ft
How is turbulence shown on significant weather chart
How is icing shown sig weather chart
Thunderstorm symbol sig weather charts w
What do thunderstorms on sig weather chart imply
Hail, mod or severe turbulence and icing
What does a convergence line look like on surface pressure chart
Effects of windshear
Handling issues, flight path deviations, airspeed loss
What are the only two times wind is measured form magnetic north
ATC/ATIS and upper wind charts
What is the geostrophic wind and what height is it found
Westerly airflow parallel to isobars with LP on left and is proportional to isobar at 2000ft+
Gradient winds
Blow around isobars at low to medium heights approx 2000ft
Where is the 2 common jet streams
Polar front 60lat and inter tropical front (sub tropical meet tropical air)
What air mass is the jetstream in
Warm air mass
Where is most of the CAT in a jetstream
Warm air but on the cold polar side, level or just above the core
What happens to surface wind direction and speed when descending
Backs and slows due to friction layer
Wind variation day and night, land and sea
Trade winds characteristics and direction
15kts at surface up to 10,000ft NE in NH and SE in SH
Sea breeze
Higher Pressure over land due to heating, so moves over sea, and air over sea moves over land
Opposite for night
4 types of depression
-orographic
-frontal
-thermal
-tropcial
Why is warm front slower
As it has to pass over denser cold front- geostrophic forced used vertically and horizontally to overcome (2/3rds)
Shallow on metar
MI
Patches on metar
BC
Low drifting on metar
DR
Blowing on metar
BL
Ice pellets on metar
PL
Small hail metar
GS
Normal hail metar
GR
Unknown precipitation metar
UP
Spray on metar
PY
Dust devils (dust/sand whirls) metar
PO
Funnel cloud metar
FC
Tornado or water spout metar
+FC
Few okta scale
1-2
Scattered okta scale
3-4
Broken okta scale
5-7
Overcast okta scale
8
What is a convergence line
It is the formation of cloud due to wind from two directions meeting and rising
Weather associated with a convergence line
A band of cloud that remains fairly stationary and can produce large amounts of rain across a relatively small area
Dust
DU
Dust storm
DS
Mist
BR
What weather expected with warm occlusion
Winter = rain, sleet, snow
Summer = heavy rain
What weather expected with cold occlusions
Winter = heavy snowfall
Summer =CBs, heavy rain and downpours
ISA deviation and altimeter error
For every 1deg deviation from ISA, the altimeter is 4ft wrong for every 1000ft
What spheres can mountain waves form
Stratosphere and troposphere
Wind speed for mountain waves
Increase with height within a stable layer above the hill (perpendicular to ridge, speed increasing )
CB cell full cycle time length
2-3hrs
When does hoar frost occur
When a/c is in sub zero clear air and suddenly enters warmer moist region
Microburst time length and area
5 min across 5km
Movement of a thunderstorm is associated with what
Wind at 10,000ft
What happens when air from air mass moves to a lower latitude
Surface air warms, humidity falls and instability increases
Large CU, temp of -20, amount the droplet will freeze is
1/4 of the droplet
Polar front position January
Florida to SW England (35deg to 65deg)
What does a secondary depression form alongside
Polar front low
What is a thermal depression
Where the land is heated faster than water, creating instability. Large land masses in summer
