APPENDIX - AIRMET DECODING

Question 1

AIRMET

Code: Report Type

Answer 1

WA = AIRMET

Question 2

AIRMET

CODE: Airspace

Answer 2

This refers to the airspace designation

CN = Canadian Airspace

Question 3

AIRMET

CODE: GFA REGION

Answer 3

Indicates the GFA region the AIRMET is for

eg. 31 = Pacific Region

Question 4

AIRMET

CODE: WMO HEADING

Answer 4

All AIRMETs issued in Canada have the same WMO heading: CWAO (Canadian Meteorological Centre/Network Operations)

CWAO

Canadian AIRMET

Question 5

AIRMET

CODE: Day/Time

Answer 5

first two digits are the day of the month
last four digits are the time in UTC/zulu

Question 6

AIRMET

CODE: BULLETIN NUMBER

Answer 6

• each AIRMET is issued a bulletin number
• new AIRMETs supersede the ones before them

Question 7

AIRMET

CODE: VALIDITY PERIOD AND ISSUING OFFICE

Answer 7

*** AIRMETS HAVE A VALIDITY PERIOD, WHICH CANNOT EXCEED 4 HOURS

They include a location indicator of the centre originating or compiling the bulletin

EG. “VALID 311355/311755 CWEG”
valid from 1355 to 1755 on 31st day of the month and was issued by CMAC-W in Edmonton (CWEG)

Question 8

AIRMET

CODE: Location indicator and name of the FIR

Answer 8

This indicates the location of the observed phenomenon and the name of the FIR

“CZEG EDMONTON FIR”

Edmonton FIR

Question 9

AIRMET

CODE: Description

Answer 9

This describes the observed phenomenon using common abbreviations

ISOLD TS OBS AT 1356Z

Isolated thunderstorm observed at 1356Z

Question 10

AIRMET

CODE: LOCATION OF THE PHENOMENON

Answer 10

This describes where the phenomena is occurring or is forecast to occur

Question 11

AIRMET

CODE: FLIGHT LEVEL AND EXTENT

Answer 11

Like SIGMETs, AIRMETs may contain the top altitude of a phenomenon or a rage of altitudes

“TOP FL260”

Tops of the thunderstorm extend to FL260

Question 12

AIRMET

CODE: MOVEMENT

Answer 12

Question 13

AIRMET

CODE: CHANGE IN INTENSITY

Answer 13

Question 14

AIRMET

CODE: REMARKS

Answer 14