Download NCEP predictor variables for the period 1948 to 2017 from here.
Note: No GCM predictors are needed for SDSM-DC.
Enter either latitude/longitude data; OR a filename - not both.
For latitude - enter either a value for north or south (not both).
Latitude/longitude should be entered as decimal degrees (for example 42.72 or 43) - not degrees and minutes.