WEATHER MATTERS



(Extracts from EASA GA Safety Team ‘Weather Anticipation’ leaflet)

POINTS OF IMPORTANCE
·    Understand weather patterns and their likely effects on your flying
·    Never fly without an aviation forecast!
·    Look for and consider PROB, TEMPO, OCNL and ISOL
·    Expect conditions to be about 30% worse than forecast!
·    Check actual conditions against the forecast
·    Identify alternative routes and suitable diversion aerodromes
·    Carry enough fuel
·    Scan the sky and horizon for possible problems
·    Avoid suspected or reported thunderstorms by at least 10 nm
·    Note local surface winds
·    Check weather reports whilst flying
·    Be prepared to divert

INFORMATION SOURCES
·    Aerodromes with FIS have a duty to provide pilots on request with METARs, SPECIs and TAFs, so ask for these whenever conditions are less than perfect
·  Check the METARS for your destination and possible diversion airfields every half hour before you depart (and en route if possible)
·   Tune in to airfields nearby which have ATIS to obtain likely conditions at your own field
·   Tune in to VOLMET broadcasts from time to time to get a broader picture
·  Take note of any TREND broadcast at the end of a report which denotes a  deterioration in visibility, cloud base etc.

SOME INDICATORS
·   Lowering pressure suggests possible worsening conditions
·   Surface wind speed or direction change occurring earlier than forecast can denote change of speed in the approach of a front
·   In Summer, wind changes can indicate nearby showers or thunderstorms
·   In Autumn or Winter, temperature and dew point comparison can indicate a likelihood of mist or fog, before visibility noticeably deteriorates
·   In the cruise, cloud below you (particularly in valleys) can indicate a potential fog hazard close to the ground
Tony Birth