Forecasting Ice

Obviously, warm temps, too much sun, and rain can wreck ice for climbing, but what are the more subtle elements of building quality ice? I'm thinking of things like depth of existing snowpack, recent rains vs. locked-in groundwater, freeze/thaw cycles, solar aspects, gullies/slabs/faces/columns, etc. 

What less-obvious signs do you look for when evaluating an uncertain forecast and guessing which climbs are likely to be in? 

All the things you listed have an affect on the ice quality and quantity. After 30 year of ice climbing I have found it easier to predict the stock market than ice conditions.

I've seen years where seldom seen climbs come in big and reliable climbs are out.