AVIATION SIGNIFICANT WEATHER

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WIND ALOFT AND TEMPERATURES CHARTS

Fnobre / 27May2012

AVIATION SIGNIFICANT WEATHER CHARTS

While weather forecasts are not 100 percent accurate, meteorologists, through careful

scientific study and computer modeling, have the ability to predict the weather patterns,

trends, and characteristics with increasing accuracy. These predictions could be showed as

Aviation significant weather (SIGWX) charts that are issued by many centers around the

world forecast ing the expected weather in the airspace

Aviation SIGWX charts are usually issued to cover three broad 'operating levels' in the

troposphere / lower stratosphere:

• low-level charts (roughly below 10000ft);

• medium / high level charts (roughly 10000ft to 45000ft); and

• high level charts (roughly above 25000ft UP TO 63000ft).

In general, the lower the level, the less area a particular chart will cover; they are

generally issued every 6 hours, with a fixed validity time 00, 06, 12 or 18 UTC, bearing in

mind that the all validity of the chart will be 3hours before and 3 hours before the fixed

validity.

Fnobre / 27May2012

AVIATION SIGNIFICANT WEATHER CHARTS

The following phenomena are shown on the charts:

• Tropical Storms

• Moderate or severe turbulence, including clear air turbulence (CAT)

• Moderate or severe icing

• Surface fronts

• Cumulonimbus (CB) cloud associated with thunderstorms and with any of the above

• Non-convective cloud associated with in-cloud moderate or severe turbulence or icing

• Jet streams (locations, altitude, strength, variations.)• Jet streams (locations, altitude, strength, variations.)

• Volcanic eruptions

• Tropopause heights ,(including 'highs' and 'lows'.)

• Radioactive material

Fnobre / 27May2012

AVIATION SIGNIFICANT WEATHER CHARTS

Tropical storm is a storm system characterized by a low-pressure center and numerous

thunderstorms that produce strong winds and heavy rain

Clear air turbulence (CAT) is the turbulent movement of air masses in the absence of any

visual cues such as clouds, and is caused when bodies of air moving at widely different

speeds meet, these areas are showed as dashed lines enclosing areas of similar

turbulence structure (intensity/height) ... base/top of layer (standard FL notation).

In aviation, Icing conditions are those atmospheric conditions that can lead to the In aviation, Icing conditions are those atmospheric conditions that can lead to the

formation of water ice on the surfaces of an aircraft,

Jet streams are fast flowing, narrow air currents found in the atmosphere they are

showed on these charts as a bold arrow showing wind location, altitude, strength and

variations.

Fnobre / 27May2012

AVIATION SIGNIFICANT WEATHER CHARTS

Troposphere is one of the lowest layers of the Earth's atmosphere, it is located right

above the planetary boundary layer, and is the layer in which most weather phenomena

take place. The troposphere extends upwards from right above the boundary layer, and

ranges in height from an average of 9 km (30,000 ft) at the poles, to 17 km (56,000 ft) at

the Equator, tropopause is the Troposphere bounderies btn estratosphere.

Tropopause is showed as spot numbers in rectangular boxes (standard FL notation) ...

boxes with upward pointing arrow denote tropopause highs ('domes') ... boxes with

downward pointing arrow denote tropopause lows (depression) downward pointing arrow denote tropopause lows (depression)

Fnobre / 27May2012

SIGNIFICANT WEATHER CHART DECODE

Fnobre / 27May2012

SIGNIFICANT WEATHER CHART DECODE

Fnobre / 27May2012

WIND & TEMPERATURE CHARTS

Fnobre / 27May2012