Aviation Decision Support InFlight and Ground Icing: what do I need to know? Marcia Politovich, NCAR Flight Planning: –Where is it? Along my planned route of flight? What altitude? Do I need to de-ice prior to takeoff? Is there freezing precipitation at my destination? –When is it? How long will the inflight or ground icing condition continue? Should I delay my flight until the weather improves? –How bad will it be? What’s the forecast severity? How does that affect my airplane? During Flight: –Have conditions changed? –Do I need to request change of flight route, altitude? –Do I need to divert to an alternate airport?

How Do We Find This Info? What are we looking for? Clouds or precipitation -40C<T<0C Supercooled liquid water Narrower T range Glaciation LWC Drop size Information sources Satellite – horizontal extent of clouds, cloud top temperature, what type of cloud PIREPs – where icing is and is not METARs – precipitation type and amount, cloud cover, ceiling height, cloud layers Radar – extent of precipitation Soundings – temperature and moisture profiles at a point Models – full temperature field, humidity, condensate less more

Products That Can Help InFlight icing: – AIRMETs and SIGMETS National Weather Service forecasts of expected moderate or greater icing over large areas for 6-h periods – SIGMETS National Weather Service forecasts of severe icing – short term, small area, usually triggered by a pilot reporting severe icing conditions – CIP and FIP Automated diagnoses and forecasts of icing including probability, expected severity, and potential for large-drop icing Hourly out to 12 h, with 20-km/1000-ft resolution – TAFs Show forecast conditions at airports – Various vendor products These supplement the products above with different displays and content, and can be free to the public or available via a subscription service

Your Web Resources NCAR Research Application Lab, Aviation Applications Program Aviation Digital Data System – ADDS Your one-stop-shopping place for AIRMETS, SIGMETS, surface conditions, TAFS, and automated CIP/FIP guidance over the CONUS – Operational: – Experimental: Aviation Weather Center: Additional products generated by NWS Alaska Aviation Weather Unit: Provides AIRMETS and SIGMETS for Alaska