CariCOF Climate Outlooks

The CariCOF Climate Outlooks for the Caribbean are prepared by the Caribbean Institute for Meteorology and Hydrology with contributions from some regional Meteorological Services.

The outlooks are produced by combining objective input (climate model output) and subjective input (experience). Precipitation forecasts from the Climate Prediction Tool (CPT – a statistical model) in the form of probabilities of above-, near-, or below normal rainfall, are balanced with similar output from dynamical climate models – i.e. general circulation models. Both model types predict seasonal rainfall based on the latest observed climate state (e.g. tropical sea surface temperatures). Currently output from climate models from the International Research Institute for Climate Prediction (IRI, including CPT), the United Kingdom meteorological Office (UKMO), and the European Centre for Medium-Range Weather Forecasts (ECMWF) are examined.

Precipitation and temperature probabilities are estimated for a number of sub-regions based on the model forecasts, the level of agreement between the different models, and a subjective confidence in the different predictions based on current conditions and a knowledge of the local climatic conditions. In addition, the probabilities provided by the various contributors are consulted to present a consistent forecast.

The precipitation and temperature outlooks are issued in the form of a map detailing tercile probabilities showing regions having homogeneous forecast probabilities for below, near, and above normal precipitation. The terciles separate the possible outcomes into three categories (terciles) based on the historical precipitation record. The probabilities add up to 100.

Tercile probabilities separate the possible outcomes into three categories/ terciles (thirds) – based on the historical precipitation record. The three categories are:

  • Above Normal – Wettest Third of the Record
  • Near Normal   – Middle Third of the Record
  • Below Normal – Driest Third of the Record

The tercile probabilities are presented in the form:

20 Percentage likelihood of above normal rainfall/temperature
45 Percentage likelihood of normal rainfall/temperature
35 Percentage likelihood of below normal rainfall/temperature