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SIGMETs and Icing Forecasts

WMO/ICAO SIGMET WORKSHOP TOKYO 2016

James LannanAviation Trainer

Aviation Weather Services, Bureau of Meteorology, Australia.

Aeronautical Forecasters Handbook

Aeronautical Forecasters Quick Guide

WMO Aviation Hazards Manual

http://www.caem.wmo.int/moodle/file.php?file=/1/AVIATION_HAZARDS.pdf

Icing Basics

6

Airframe IcingForecast Process

Identify synoptic weather systems favourable for icing

Analyse the cloud types and phases (Water/Supercooled Liquid/Ice)

Analyse wind & temperature profile of cloud

Identify any mesoscale factors that may influence icing severity

Estimate icing type and severity based on temperature and cloud type

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The Detailed Icing Forecast

Icing Case Study – Southern Australia11th August (Winter) 2300UTC – 0600UTC

Radiosondeobservation.

11th Augustat 2300Z

Red is current.

Blue is 12HRprevious.

NWP Data: ACCESS R - 0700UTC

The Icing SIGMET

WSAU21 ASRF 120520 YMMM SIGMET M02 VALID 120600/121000 YSRF -YMMM MELBOURNE FIR SEV ICE FCST WI S3430 E14430 – S3200E14900 – S3500 E15200 – S3700 E14530 - S3430 E14430 FL050/120 STNR NCRMK: MM EXTD M01 120200/120600=

Graphical SIGMETs - 0641UTC