A new
map was introduced today to CFN.
Precipitable Water represents the water content in the (column above) atmosphere.
Imagine if all the available moisture above you actually precipitated to the ground, then the (precipitable water) value would represent the amount of rainfal.
Higher precipitable water = Lower transparency.
This new
map in conjunction with the Water Vapour
satellite image should give you a good indication of your transparency conditions.
Precipitable Water is available for both GFS and ACCESS-R/ACCESS-G on all regions.