Ok just wow! Humid here in the Sydney basin Penrith dew points 17C but Blackheath dew points -8.7C with a westerly wind! That spells trouble for bushfires in the western parts of the mountains - it remains to be seen just how close the boundary will advance during the day. This will in turn impact fires in those areas ie westerly winds. Incidentally, it will be interesting to see how shallow and how deviant the soundings will be.