1.I used regions, stations types, DEM, GlobCover, soil map and month averaged MODIS. Also take into account the last 5 SNOTEL/CDEC measurements.
2.My solution is optimal interpolation based on neural network gaussian process.
In this approach the parameters of the gaussian process calculation using the neural network. The correlation function is homogeneous in virtual multi - dimensional (5-7d) space. The mapping on this virtual space is a 2-layer perceptrons takes into account all predictors.
Hey FBykov, would you mind sharing a little more information in my post here: Care to share general methodologies? ? It would be awesome to hear more about what you did, it sounds like you took a really interesting approach!