Reima Eresmaa, Ulf Andrae, Lars Berggren, John Bjørnar Bremnes, Carl Fortelius, Inger‐Lise Frogner, Erik Gregow, Rafael Grote, Martin Ridal, Ole Vignes, Ivar Ansper, Roohollah Azad, Jevgenijs Begens, Lisbeth Bergholt, Jostein Blyverket, Laila Daniel, Bjørg Jenny Engdahl, Helene Erlandsen, Mehdi Eshagh, Mikael Hasu, Mariken Homleid, Petter Ideström, Karl-Ivar Ivarsson, Alina Lerner-Vilu, Ahto Mets, Sintija Moldengauere, Gunnar Noer, Elmeri Nurmi, Mikko Partio, G. Prieditis, Eerik Saarikalle, David Schönach, Metodija Shapkalijevski, Kertu Sild, Vladislavs Sitčihins, Niko Sokka, Siri Spjelkavik, Andreas Tack, Aleksei Vaštšenko, Anders Wettergren, Kaisa Ylinen, Uldis Zandovskis
Abstract The governmental meteorological offices of Estonia, Finland, Latvia, Norway, and Sweden maintain joint production of regional forecasts based on numerical weather prediction (NWP). The collaboration is organized in a continuing project called Meteorological Cooperation on Operational NWP (MetCoOp). The operational products contribute to weather data for daily use and form the base for official weather warnings in the participating countries. The forecasts are distributed to the public, to specific users such as the national road authorities, and to other governmental institutes. MetCoOp operates two NWP suites: 1) The MetCoOp Ensemble Prediction system (MEPS) is a lagged ensemble of 30 members that is updated hourly by running five members out to the 66-h lead time, whereas 2) the MetCoOp Nowcasting System (MNWC) is a deterministic run out to the lead time of 12 h. The suites share a common modeling domain that covers Scandinavia, Finland, and Baltic countries with 2.5-km horizontal grid spacing. There is an additional postprocessing suite, the MetCoOp Ensemble Calibration System (MECaS), that uses the raw MEPS forecast as input. MECaS produces a statistically calibrated ensemble forecast of near-surface parameters in a 1-km grid. The convection-permitting grids and frequent update cycles create added value on top of global forecasts that are received at no finer than 8-km horizontal grid spacing and no more than two–four times per day.