Computing the monthly Palmer Drought Index on a weekly basis: A case study comparing data estimation techniques

[1] A methodology is presented for estimating mean monthly temperature and total monthly precipitation before the month is over. The approach involves combining observed data for the month to date with daily normals for the remainder of the month. It is demonstrated to be superior to two other techniques, a persistence method and a moving window method. This normals technique allows the computation of an operational monthly Palmer Drought Index on a weekly (or even daily) basis which is consistent with historical drought indices of the recent past.