U.S. Aviation Weather Maps & Symbols

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U.S. Aviation Weather Maps & Symbols

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Those working in aviation must possess a special knowledge of weather and how certain weather conditions impact their operations. Because of this, a special set of weather maps exists solely for aviation purposes.

Of course, these weather maps look nothing like the ones we're used to seeing for our daily surface weather--explore them in the following slides!

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Icing

NOAA NWS

Icing maps depict icing severity from a height of 1,000 feet up to 30,000 feet above mean sea level. Locations of confirmed icing reports are also shown.

Symbol Key

Solid fill colors = Areas where icing conditions are predicted to occur.
Blue shading = Levels of icing severity ranging from trace (lightest blue) to heavy (dark blue).
Red shading/SLD threat = Areas where supercooled large drops are detected. Special warning should be taken in these regions, as SLDs are an indication of severe icing potential.
Ψ = Icing severity symbol. It marks locations where a PIREP icing report has been received. Symbols with no lines represent a trace of icing; one line, light icing; two lines, moderate icing; and three lines, severe icing.

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Freezing Levels

NOAA NWS

Freezing level maps show areas where air temperatures aloft are at or below freezing (32°F/0°C).

Symbol Key

Solid fill colors = The lowest height at which freezing temperatures over an area exist. Freezing levels range from the surface (purples and blues) up to 17,000+ feet (oranges, reds, hot pinks). Levels are measured in hundreds of feet above mean sea level and are drawn at intervals of 2000 feet.

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Turbulence

NOAA NWS

Graphical turbulence guidance maps show turbulence intensity from a height of 10,000 to 45,000 feet (flight level 450).

Symbol Key

Solid fill colors = Areas of turbulence ranging from light (light green) to moderate or greater (dark yellow).
Λ = Locations where PIREP turbulence reports have been received. Symbols with a single peak represent moderate turbulence; two peaks, severe turbulence.

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AIRMETs

NOAA NWS

Graphical AIRMETs, or G-AIRMETs, show areas having terrain (Sierra), turbulence (Tango), and icing (Zulu) hazards.

Symbol key

An orange boundary (turbulence symbol) indicates high turbulence. The altitude range is included in an orange details box. The top number gives the height of the top of the turbulence layer; and the bottom number gives the altitude of the bottom of the turbulence layer. Altitudes are labeled in hundreds of feet.
A red boundary (turbulence symbol) indicates low turbulence. The altitude range is included in a red details box. The top number gives the height of the top of the turbulence layer; and the bottom number gives the altitude of the bottom of the turbulence layer. Altitudes are labeled in hundreds of feet.
A pink boundary (dashed) indicates mountain obscurity. The cause for obscuration of mountain peaks is listed at the bottom of a pink details box. Codes are as follows: CLDS clouds; PCPN precipitation; BR mist; FG fog; HZ haze; FU smoke.
A purple boundary (solid line) indicates areas where Instrument Flight Rules are required. The cause for low ceiling or reduced visibility is listed at the bottom of a purple details box. Codes are as follows: PCPN precipitation; BR mist; FG fog; HZ haze; FU smoke; BLSN blowing snow.
A dark blue boundary (circle, line dashed) indicates icing conditions. The altitude range is included in a blue details box. The top number gives the height of the top icing layer; and the bottom left number gives the height of the lowest icing layer. If a bottom right number is listed, it means the bottom of the icing layer varies between these altitudes over the specific area. Altitudes are labeled in hundreds of feet.
A blue boundary (zig-zag and tick marks) indicates freezing levels. Freezing level altitude can either be listed as a single number or a range if freezing occurs at multiple heights.

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Convective SIGMETs

NOAA NWS

These highlight areas where there is a current active threat of thunderstorms, or the growing potential for them. (Note: Non-convective SIGMETs, which cover severe or extreme turbulence or icing conditions follow the for AIRMETS.)

http://aviationweather.gov/adds/phputils/wrap_image.php

A red boundary (solid line) with a matching thunderstorm symbol indicates current active convective SIGMETs.
An orange boundary (shaded) with a matching thunderstorm symbol indicates convective SIGMET outlooks.