SIGMET These messages are intended to provide short term warnings of certain potentially hazardous weather phenomena. These messages are intended to provide short term warnings of certain potentially hazardous weather phenomena. Warnings are issued for: Warnings are issued for: –active thunderstorm areas, –lines of thunderstorms, –heavy hail, –severe turbulence or icing, –marked mountain waves, –hurricanes, –widespread sand or dust storms, –volcanic ash, –and low level windshear.

SIGMET Sigmets are meant especially to warn pilots who are already flying about severe weather Sigmets are meant especially to warn pilots who are already flying about severe weather Sigmets are broadcast by VFR and IFR air traffic control units, FSS, and are available on the Navcanada weather website. Sigmets are broadcast by VFR and IFR air traffic control units, FSS, and are available on the Navcanada weather website.

SIGMET WSCN31 CWTO SIGMET A1 VALID / LN TSTMS 30NM WIDE MAX TOPS 400 OBSRVD AT 0400Z FROM LONDON-TORONTO-PETERBOROUGH. LN MOVG SWD ABT 20 KTS AND INTSFYG. TSTMS MOVG OUT OF AREA BY 0730Z. Significant Meteorological Report Severe Icing or Turbulence not associated with convective clouds Large area for dust storm or sandstorm (most likely in the Prairies) Possible volcanic ash clouds, hurricanes and tropical storms (uncommon in Canada)

SIGMET Line of thunderstorms or active area of thunderstorms Severe Squall Line Mountain Waves (mostly Rockies) Heavy hail (rarely) Tornado or Water Spout Low level wind shear

PIREPs (PIlot REPorts) PIREPs are reports of weather conditions encountered by aircraft during flight. PIREPs are reports of weather conditions encountered by aircraft during flight. Pilots are encouraged to file brief reports of weather conditions especially reports of any significant atmospheric phenomena that differ from forecast. Pilots are encouraged to file brief reports of weather conditions especially reports of any significant atmospheric phenomena that differ from forecast. PIREPs are usually reported to Flight Service Stations but can be passed along to Air Traffic Control as well. PIREPs are usually reported to Flight Service Stations but can be passed along to Air Traffic Control as well.

PIREP (AIM MET 2-0) UACN10 CYXU YZ UA /OV YXU /TM 2120 /FL080 /TP PA31 /SK 020BKN OVC /TA 12 /WV /TB MDT BLO 040 /IC LGT RIME /RM NIL TURB CYYZ CYHM TRY TO DECIPHER THIS FOR YOURSELF Go to: /tp14371/met/3-0.htm# /tp14371/met/3-0.htm#3-17 to see how you did!

PIREPS Significant weather that can be reported by PIREP includes, but is not limited to: Significant weather that can be reported by PIREP includes, but is not limited to: –Clear Air Turbulence –Wind Shear –Airframe Icing –Volcanic Ash –Pilot Estimation of Surface Wind

Levels of Turbulence (AIM-MET 3.7) INTENSITYAIRCRAFT REACTIONREACTION INSIDE AIRCRAFT LIGHT Turbulence that momentarily causes slight, erratic changes in altitude and/or attitude (pitch, roll, yaw). Report as “Light Turbulence”. OR Turbulence that causes slight, rapid and somewhat rhythmic bumpiness without appreciable changes in altitude or attitude. Report as “Light Chop”. Occupants may feel a slight strain against seat belts or shoulder straps. Unsecured objects may be displaced slightly. Food service may be conducted and little or no difficulty is encountered in walking.

Levels of Turbulence (AIM-MET 3.7) INTENSITYAIRCRAFT REACTIONREACTION INSIDE AIRCRAFT MODERATE Turbulence that is similar to Light Turbulence but of greater intensity. Changes in altitude and/or attitude occur but the aircraft remains in positive control at all times. It usually causes variations in indicated airspeed. Report as “Moderate Turbulence”. OR Turbulence that is similar to Light Chop but of greater intensity. It causes rapid bumps or jolts without appreciable changes in aircraft altitude or attitude. Report as “Moderate Chop”. Occupants may feel a slight strain against seat belts or shoulder straps. Unsecured objects may be displaced slightly. Food service may be conducted and little or no difficulty is encountered in walking.

Levels of Turbulence (AIM-MET 3.7) INTENSITYAIRCRAFT REACTIONREACTION INSIDE AIRCRAFT SEVERE Turbulence that causes large, abrupt changes in altitude and/or attitude. It usually causes large variations in indicated airspeed. Aircraft may be momentarily out of control. Report as “Severe Turbulence”. Occupants are forced violently against seat belts or shoulder straps. Unsecured objects are tossed about. Food service and walking impossible. NOTES 1: Occasional: Less than 1/3 of the time. Intermittent: 1/3 to 2/3. Continuous: More than 2/3.

Icing Types and Intensities INTENSITYICE ACCUMULATION Trace Ice becomes perceptible. The rate of accumulation is slightly greater than the rate of sublimation. It is not hazardous, even though de- icing or anti-icing equipment is not used, unless encountered for an extended period of time (over 1 hour). Light The rate of accumulation may create a problem if flight is prolonged in this environment (over 1 hour). Moderate The rate of accumulation is such that even short encounters become potentially hazardous, and use of de-icing or anti-icing equipment or diversion is necessary. Severe The rate of accumulation is such that de-icing or anti-icing equipment fails to reduce or control the hazard. Immediate diversion is necessary. *Rime ice: Rough, milky, opaque ice formed by the instantaneous freezing of small supercooled water droplets. *Clear ice: Glossy, clear, or translucent ice formed by the relatively slow freezing of large supercooled water droplets.

Icing types Clear Ice (there is a bit of mixed here too) Rime Ice

PIREP report Mixed Icing