Seasonal Monitoring and Probability Generator Tool (SMPG)

The SMPG is a powerful analytical tool designed to monitor the progression of the rainfall season by blending rapidly updated station observations, gridded rainfall data, and forecast information. To ensure seamless integration into existing workflows, the SMPG is designed as a plugin for QGIS. It utilizes time series data extracted for each polygon, making it an intuitive addition to GIS-based monitoring and analysis systems. The SMPG tool is designed to work with the outputs of the GeoCLIM, which is also available as a QGIS plugin. The GeoCLIM can be used to generate Improved Rainfall Estimates (IRE) by blending satellite-based gridded datasets with meteorological station observations. Users can also input time series data into SMPG from their custom workflows.

The SMPG Objective

Crop performance is often sensitive to variations in seasonal rainfall totals, as well as to the distribution of rainfall during the season. At the same time, reporting from weather stations to global data pipelines has declined, reducing access to high-quality in situ observations. The SMPG enables National Meteorology and Hydrological Services to leverage the best available rainfall information—combining local station data with gridded products—to deliver reliable, high-quality climate information to users.
 

How the SMPG Works

The SMPG tool ingests IRE time series that have been spatially averaged over user-defined polygons (e.g., districts, livelihood zones, or agricultural regions). These polygon-level time series are then used to compare rainfall data from the Start of the Season to the current period with long-term averages (LTA) and historical records from user-selected analog years. The analog years are selected based on the climatology for the area of concern and current climate modes.
 
The SMPG also features an Outlook Module that simulates and calculates probabilities for the End of Season by completing the season with rainfall forecast and historical data from the analog years. 
 
Below are some examples of SMPG outputs: 
  • Current Dekad/LTA Pct.: the percent of average of the long-term average (LTA) for the accumulated precipitation from the Start of Season (SOS) up to the current period (e.g. current dekad).
  • Ensemble Med./LTA Pct.: the percent of average for the EOS median value of all possible outcomes compared against the long-term average (LTA).
  • Probability Below Normal: the probability of the season ending below normal (<33rd percentile).
  • Probability Normal: the probability of the season ending normal (between the 33rd and 67th percentiles).
  • Probability Above Normal: the probability of the season ending above normal (>67th percentile).
  • Ensemble Med. Pctl.: the percentile rank of the median value of all possible outcomes at the End of Season (EOS).
  • Current Season Pctl.: the percentile ranking of the seasonal accumulation of rainfall from the SOS up to the current period, based on historical data.
  • C.Dk. + Forecast/LTA Pct.: the percent of average of the accumulated rainfall from the SOS up to the current period, including the forecast.

Example

Below is an example of SMPG plots routinely produced for the East African region alongside Agroclimatology monitoring reports.
The map on the left shows the probability of the 2025 October-December rainfall season ending below normal, derived using the SMPG tool and based on Improved Rainfall Estimate (IRE) data using CHIRPS and additional station data from the Kenya Meteorological Department (KMD), Ethiopia Meteorological Institute (EMI), the Somalia Department of Meteorology and FAO SWALIM. The region in white is currently off season. The plot on the right shows the seasonal rainfall accumulation from the start of the season to the current dekad. 
 
 

Fig. 1. A map of East Africa showing the probability of the 2025 October-December rainfall season ending below normal (left) and IRE seasonal rainfall accumulation in Isiolo North (Kenya) from the start of the season to the November dekad 3 plus forecast (right). The blue bars show the dekadal rainfall accumulation, the red line shows the long term average (LTA) and the purple bar shows the rainfall forecast for the next dekad.

The QGIS SMPG tool plugin and installation guide can be found here.

Video Tutorial: Youtube