The WMO WIPPS Weather Forecast Data Supporting Early Warnings For ALL

Many parts of the world are covered by advanced weather forecast systems and communication infrastructures which allow National Meteorological and Hydrological Services (NMHSs) to issue sophisticated warnings to civil protection agencies and the public in their countries, to protect people and assets from the impacts of severe weather. However, many other areas, particularly in developing and least developed countries, do not have ready access to such systems, so that NMHSs with limited resources have very limited capabilities to provide such warning services. People in the same countries are often particularly vulnerable to the impacts of severe weather, made worse by climate change altering the nature of weather-related hazards, and also issues like displaced populations. The WMO Integrated Processing and Prediction System (WIPPS) aims to support the United Nations Early Warnings for All (EW4All) initiative by making weather forecast data from advanced countries’ forecast systems, many of which have global or regional coverage, readily available to every NMHS to help enable them to provide effective warnings.

WIPPS operates as a network of designated centres, most of which are hosted voluntarily by the more advanced and better resourced NMHSs, which make defined minimum amounts of data essential for operational services freely available for free and unrestricted use by any WMO Member’s NMHS. The minimum data required to be provided by WIPPS Designated Centres for global Numerical Weather Prediction (NWP) has been greatly increased in 2024, particularly with EW4All in mind. The spatial and temporal resolution of data to be shared has been substantially increased to provide better detail on the severity of predicted local weather, enabling better estimation of the potential impacts of that weather. Also, the range of weather variables to be provided has been greatly enhanced with a focus on surface weather elements, reflecting the much-enhanced capability of modern global NWP systems to represent local weather realistically, again to support the issue of impact-based early warnings. Recognising that the most impactful weather is often the most challenging to predict in detail, WIPPS (including under its former name of GDPFS) has always been at the forefront of promoting the use of ensemble prediction systems to better estimate the uncertainties and risks of high-impact weather. For effective EW4All it is vital to understand not only the most likely weather outcome, but also the risk of so-called HILL (High-Impact Low Likelihood) events. In order to support the issue of HILL event risk-based warnings, the recent enhancement to WIPPS minimum data requirements has changed the ensemble data provision from a simple “mean and spread” presentation to a requirement to provide a set of quantile values describing the full probability distribution for most weather elements. A few are provided as probabilities where more appropriate.