Scripts to help create manageable catchment-scale time series out of Ben Livneh's hydrometeorology data products: http://ciresgroups.colorado.edu/livneh/data:
Livneh, Ben, et al. "A long-term hydrologically based dataset of land surface fluxes and states for the conterminous United States: Update and extensions." Journal of Climate 26.23 (2013): 9384-9392.
Now updated to also work with David Pierce's extended (and slightly different) data product: http://cirrus.ucsd.edu/~pierce/nonsplit_precip/
Pierce, David W., et al. "An Extreme-Preserving Long-Term Gridded Daily Precipitation Dataset for the Conterminous United States." Journal of Hydrometeorology 22.7 (2021): 1883-1895.