Seasonal variability and predictability of monsoon precipitation in
Rainfed agriculture is the mainstay of economies across Southern Africa,
where most precipitation is received during the austral summer monsoon.
Despite that, seasonal precipitation predictability in Southern Africa
is less explored. Here we use three natural climate forcings, El
Niño–Southern Oscillation (ENSO), Indian Ocean Dipole (IOD), and the
Indian Ocean Precipitation Dipole (IOPD) – the dominant precipitation
variability mode – to construct an empirical model that exhibits
significant skill over Southern Africa during monsoon in explaining
precipitation variability and in forecasting it with a five-month lead.
While most explained precipitation variance (50–75%) comes from
contemporaneous IOD and IOPD, preconditioning all three forcings is key
in predicting monsoon precipitation with a zero to five-month lead.
Seasonal forecasting systems accurately represent the interplay of the
three forcings but show varying skills in representing their
teleconnection over Southern Africa. This makes them less effective at
predicting monsoon precipitation than the empirical model.