Transcript Air Law - Blackbushe Aviation

Midweek Seminars
Meteorology – Jet Streams Fronts and Air Masses
Connecting the Weather
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Air Masses
Fronts
Jet Stream
Quiz
Midweek Seminars
Meteorology – Jet Streams Fronts and Air Masses
Air Masses
A mass of air takes on Temperature and Moisture from
where the source of air originates.
Source Region - Land or Sea
Amount of Time over the Source region
Modification as the Air Mass moves away from the source.
Midweek Seminars
Meteorology – Jet Streams Fronts and Air Masses
Air Mass Classification and humidity
Artic – Polar Ice Cap in Winter
Polar – Forms 40’ to 60’, Summer up to 80’
Tropical – Forms from high pressure cells, Summer over
large continents
Equatorial – Region between Sub tropical Highs
Humidity depends on source
Maritime – Forms over Water – more humid
Continental – Originates over Land – less humid
Midweek Seminars
Meteorology – Jet Streams Fronts and Air Masses
Air masses affecting the UK are either Polar or Tropical with Artic air mass in winter
Midweek Seminars
Meteorology – Jet Streams Fronts and Air Masses
What happens as an Air Mass moves from Cold to Warm?
Air becomes heated in the Lower Levels
To pilot this gives you..
Unstable Air
Warmer Air
Low Humidity
What happens as an Air Mass moves from Warm to Cold?
To pilot this gives you..
More stable air
Colder in lower levels
Increased Humidity
Midweek Seminars
Meteorology – Jet Streams Fronts and Air Masses
Air Masses
Polar Maritime
Source – Greenland & Iceland
Conditions at Source
Cold
Stable
High Humidity
As Air Mass moves South East becomes Unstable resulting in
Cu and Cb over Land
Heavy Showers, Rain, Hail
Moderate to severe Icing
Good Visibility
Midweek Seminars
Meteorology – Jet Streams Fronts and Air Masses
Air Masses
Tropical Maritime
Source – Azores
Conditions at Source
Warm
Slight Instability
Moderate Humidity
As Air Mass moves North East Air cools from below
Advection Fog
St & Sc by day
St at night
Poor Visibility
Midweek Seminars
Meteorology – Jet Streams Fronts and Air Masses
Air Masses – Tropical continental
Source – North Africa
Conditions at Source
Warm
Stable
Low Humidity
As Air Mass moves North it cools from below becomes more stable,
Humidity stays low.
Hot & Dry weather
Poor Visibility due to Haze
Midweek Seminars
Meteorology – Jet Streams Fronts and Air Masses
Air masses, Arctic Maritime, Winter only
Source – Artic Circle
Conditions at Source
Cold
Stable
Low Humidity
As Air Mass moves South it is heated from below
becomes VERY unstable,
Cold
Moist - Precipitation
Heavy Snow
Cu & Cb Clouds
Unstable
Possible Thunderstorms
Midweek Seminars
Meteorology – Jet Streams Fronts and Air Masses
Air Masses, Polar continental, Winter only
Source – Siberia & North Europe
Conditions at Source
Cold
Stable
Low Humidity
As Air Mass moves over cold land of Europe it stays cold and stable
Cold
Very Dry
No Precipitation
Possible Thunderstorms along east coast if Air Mass has moved over
North Sea
Midweek Seminars
Meteorology – Jet Streams Fronts and Air Masses
Midweek Seminars
Meteorology – Jet Streams Fronts and Air Masses
Coffee!!!!!
Midweek Seminars
Meteorology – Jet Streams Fronts and Air Masses
When Air Masses meet we call them… Fronts
A front is a zone of transition between two contrasting
air masses
The three types of front are
Cold
Warm
Occluded
The interaction of two air masses at the frontal
surface frequently gives rise to a great deal of frontal
cloud and weather.
Midweek Seminars
Meteorology – Jet Streams Fronts and Air Masses
Fronts
Typical cross section through a frontal system
Midweek Seminars
Meteorology – Jet Streams Fronts and Air Masses
Warm front
Midweek Seminars
Meteorology – Jet Streams Fronts and Air Masses
Warm Front Weather
Wind veers & increases slightly
Temperature / Dewpoint rise.
Pressure steadies
Precipitation changes from RA to DZ or DZRA.
Cloud changes from NS to ST or SC.
Midweek Seminars
Meteorology – Jet Streams Fronts and Air Masses
Cold Front
Midweek Seminars
Meteorology – Jet Streams Fronts and Air Masses
Cold Front Weather
Pressure rises rapidly
Wind veers and decreases slightly
Temp / Dew point fall.
Visibility improves
Intermittent Rain Heavy Showers begin from NS / Embd Cb
Midweek Seminars
Meteorology – Jet Streams Fronts and Air Masses
Midweek Seminars
Meteorology – Jet Streams Fronts and Air Masses
Warm Occlusion
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Air Masses
Fronts
Jet Stream
Quiz
Less cold air over-rides colder air ahead.
Midweek Seminars
Meteorology – Jet Streams Fronts and Air Masses
Cold Occlusion
Colder air under-cuts less cold air ahead
Midweek Seminars
Meteorology – Jet Streams Fronts and Air Masses
Midweek Seminars
Meteorology – Jet Streams Fronts and Air Masses
Jet Streams
A jet stream is an river of high velocity air with velocities of 60 – 250kt, on rare
occasions 300kt flowing generally west to east
It is a wind belt in created by thermal wind in a boundary zone between warm and
cooler air i.e. a frontal zone. It usually separates the colder and warmer air.
Midweek Seminars
Meteorology – Jet Streams Fronts and Air Masses
Jet Streams
Max wind speed in a Jet Stream is found on the warm side of the
frontal zone at an altitude just above than of the cold tropopause and
below that of the warm tropopause and the direction usually agrees
with that of the front.
Midweek Seminars
Meteorology – Jet Streams Fronts and Air Masses
Connecting the Weather
Interpretation of Wx info
Tips for en route Wx interpretation and cross referencing Met charts
Example: F215 shows vis 999 ocnl SHRA 4km vbis cloud 2500 ocnl 1500
METAR 9999 BKN 2500 SHRA ; TAF 9999 BKN 2500 PROB30 TEMPO 5000
+SHRA
AIRMET Says cold front with gusting winds passing early in day, isolated heavy
showers later
Conclusion, flight can go ahead, choose alternate carefully and proceed with
caution.
Midweek Seminars
Meteorology – Jet Streams Fronts and Air Masses
Quiz
Define CAVOK
More than 10k vis, no cloud below 5000ft or MSA, no CuNim in vicinity
SHSNRA VV003
Heavy showers of snow or rain, vertical visibility 300ft
An airmet says Cold Sector. Conditions?
Colder dryer air, good vis, scattered cumulus
METAR : EGLF 031450Z 02012KT 6000 BKN017 04/00 Q1034. Flyable?
Yes
METAR : EGLF 031450Z 02012KT 9000 OVC005 04/04 Q1004. Flyable?
No
TAF says PROB30 TSRA BKN 020 flyable?
Yes with caution
PROB50 Exists?
No, any more than PROB40 is BCMG or TEMPO
Met Office website
Form 214-215
TAFs, METARs, AIRMET
Other sites, XCweather.co.uk, avbrief.co.uk, sky demon
Midweek Seminars
Meteorology – Why it’s a bad idea to bypass proper Met planning