More about Early Estimates

CHC Early Estimates: Recent Rainfall and Seasonal Rainfall Monitors

 
The CHC Early Estimates provide a tool for monitoring rainfall conditions using combinations of CHIRPS, preliminary CHIRPS, and the CHIRPS-GEFS 15-day forecast.  The Recent Rainfall Monitor provides near-real-time estimates of rainfall accumulations for the most recent pentad (5-6 days) to the most recent 18 pentads (3 months), as well as combining these intervals with an outlook of how forecast rainfall would affect these accumulations. The Seasonal Rainfall Monitor provides near-real-time estimates of rainfall accumulations for region-specific agricultural rainfall seasons ranging from 3 to 6 months. Multiple variables, from rainfall totals to historical rank, are provided to support agro-climatological assessments. To-date rainfall values are based on preliminary CHIRPS data for the most recent pentads, and CHIRPS final data, when available. The outlook combines these to-date accumulations with a rainfall forecast for the next three pentads (15-16 days) using CHIRPS-GEFS. CHC Early Estimates have the same latency as CHIRPS preliminary data and are updated on the 2nd, 7th, 12th, 17th, 22nd, and 27th of each month, with the Seasonal Rainfall Monitor only being updated during the seasons of interest. 
 
Access to regional maps and near-global data is provided here for the Recent Rainfall Monitor version of the CHC Early Estimates. Correspondingly, access to the regional maps and data for the Seasonal Rainfall Monitor can be found here.
 
The CHC Early Estimates products include rainfall totals (Total), difference from the 1981-2018/19 average (Anomaly), percent of average (% Average), standardized anomalies (SPI), and historical rank for the 1st to 3rd wettest or driest (Rank). Early Estimates include preliminary and forecast data, thus the information is subject to change. All products are back-processed when CHIRPS Final is made available in order to ensure the most accurate estimates. The latest year of Recent Rainfall Monitor graphics and products are available from the data portal, and only the most recent season of the Seasonal Rainfall Monitor graphics are available.
 
Recent Rainfall Data Access
 
Geotiffs of these products are available for download for the full CHIRPS extent (50N-50S, 180W-180E, 0.05° resolution). The geotiffs are not subset by region.  
 
The Recent Rainfall Monitor regional maps (pngs) can be accessed here for Africa, East Africa, West Africa, Southern Africa, Central America and the Caribbean, South America, and Central Asia. The left-side links lead to pngs showing to-date rainfall values. The “+Forecast” section links to the outlook, which includes the 3-pentad CHIRPS-GEFS forecast. The usage of preliminary or forecast data sources, and corresponding dates, are documented on the maps. 
Archived maps and data can also be retrieved from the links below.
 
For to-date accumulations: 1-pentad2-pentad6-pentad12-pentad18-pentad
For the outlook:                                  5-pentad9-pentad15-pentad, 21-pentad
 
Seasonal Rainfall Data Access
 
The latest regional maps for each season can be viewed on the CHC Early Estimates Seasonal Monitor page. Regions include East Africa, West Africa, and Southern Africa. Archived maps (pngs) and data (geotiffs) can be retrieved using the links below. The “with_forecast” subdirectories within the “png” and “tif” directories contain outlook maps and data, including forecast information.
 
East Africa             Mar - Sep     Apr - Jun     Jun - Sep     Sep - Dec     Oct - Dec
 
West Africa            May - Sep    Jun - Sep
 
Southern Africa     Oct - Apr      Dec - Feb
 
 
Please send comments and inquiries to Will Turner and Laura Harrison (will.turner@geog.ucsb.edu ; harrison@geog.ucsb.edu)