The ‘Avoid TS/FG’ in the suggested alternates section seems to be hiding airfields that don’t have either ‘TS’ or ‘FG’ in their METER or TAF. What other factors does this option take into account?
This morning EGCC was not suggested as a viable alternate, but when I select ‘Allow TS/FG’ it appears in the list. There’s no mention of FG/TS/BR/CB in the METAR/TAF?
Hi, possible heavy precipitation (+RA, +SN) is why EGCC was being avoided this morning:
TAF EGCC 170504Z 1706/1812 17011KT 9999 SCT025
BECMG 1706/1709 18015G30KT
TEMPO 1707/1801 7000 RA BKN014
PROB40 TEMPO 1708/1801 3000 +RA RADZ BKN009
BECMG 1722/1801 23008KT
PROB30 TEMPO 1803/1810 BKN009
BECMG 1809/1812 12010KT
TEMPO 1810/1812 7000 RA BKN009
PROB30 TEMPO 1810/1812 4000 +RA BKN004=
Heavy rain has the potential to cause standing water or flooding, which while unlikely, could close an airport. Heavy snow can also close an airport for obvious reasons.
Other weather phenomena that are avoided are hail (GR), volcanic ash (VA), and funnel clouds/tornados (FC).
I will update the documentation to mention these in the next update.
Best regards,