Although rainfall deficit is technically meteorological drought, and drought could be of several other types (such as hydrological, agricultural, etc.), the attempt here is to demonstrate the use of R in the analysis of high resolution rainfall data. Using 4-km rainfall data from the PRISM Climate Group for 1895-2013, the total for 2013 is compared with the long-term and near-term historical averages.
Spatial patterns compare well with those from the Drought Monitor from the University of Nebraska.
The entire code and all the graphics are available on GitHub - https://github.com/RationShop/rain_prism
This effort is part of The Rain Project.
Any comments or help appreciated.