Are GRIB files consistently optimistic ?

This question has been asked regularly, but until now I had never wanted to publicly give my opinion on the subject so as not to offend anyone and especially not to create unnecessary controversy. But by dint of doing it during my training, why not express it openly ?

My opinion, forged by observation and a long professional experience in pleasure boating (¹), is that this assertion of the systematic optimism of the GRIB forecasts regarding wind force, which unfortunately continues, no longer has a reason to be, and has not been verified in fact for some time. Read more …

Predict thunderstorms with Weather4D


In Weather4D (all versions) most weather models provide a data calledCAPE.

Convective Available Potential Energy, in French : Energie potentielle de convection disponible. Behind this abstruse acronym hides a powerful tool for forecasting thunderstorms. The CAPE is measured in joules per kilogram of air (J / Kg) and defines the vertical thrust energy of a hot air particle in a colder atmosphere. In other words, vertical acceleration of the air particle will be directly related to this energy measurement. Read more …

New major evolution of the GFS model

NOAA (¹) annouced on 22 March a major upgrade to its weather forecast model GFS.

For the first time, charts portfolio on Global Forecasting System (GFS), NOAA's flagship weather forecast model (¹) will be coupled to the global wave model Wave Watch III (WW3), produced by the FNMOC (Fleet Numerical Meteorology and Oceanography Center), which will extend the current forecast of waves from 7 up to 16 days and improve forecasting of atmospheric-forced ocean waves. Read more …

Sea state : interpret wave patterns

In Weather4D, as generally in other applications, sea ​​state forecasts are described by ocean models. The most used is the model WW3 (Wave Watch III), published by the FNMOC (Fleet Numerical Meteorology and Oceanography Center) of the US Navy, with a Global model due 7 days and resolution 1 ° (60NM), and a European model at 3 days and resolution 0.2 ° (12NM). Meteo France publish modelsMFWAM (Wave Assimilated Model) coupled with the ARPEGE and AROME weather models with three resolutions : Global at 0.5 ° (30NM), Europe at 0.1 ° (6NM), France at 0.025 ° (1,5NM) with variable deadlines (¹). Read more …

Routing : from game to reality (continue)

Friday 13 November will not be a lucky day for the Vendée Globe skippers 2020 (¹). They will have to negotiate the meeting with the tropical storm "Theta" which crosses their course with average winds which can reach the 40 knots and strong gusts. Especially the sea will be to fear because, strongly crossed when passing the low pressure center, the waves may exceed the 6 meters and surge chaotically. Read more …

Routing : from game to reality

On the second day of racing in this Vendée Globe 2020, we can say that the weather conditions that the skippers will experience on the descent to the Doldrums will be particularly tough. After a departure by a young lady, a first not very active cold front which passed without a hitch, the loners will cross a second much more violent front in the night and morning from Tuesday to Wednesday, for the group going to the West, and in the evening for the group spent between the DST (¹) la France.

But these conditions to come are quite different for Virtual Regatta players andfor sailors… Read more …

ECMWF weather data soon open to the public [2part]

Source : The Parliament Mag by Umberto Modigliani, deputy director of forecasts of ECMWF, responsible, with the department director, continuous production of forecasts and user relations.

Beginning of October, the European Center for Medium-Range Weather Forecasts (CEPMMT) will take a big step forward by making hundreds of its forecast maps freely available to all.
These changes are part of a large European initiative to make public sector data free and open, to encourage innovation and support a thriving data-driven digital economy.

Until now, full access to these forecast charts was restricted to national meteorological and hydrological services of ECMWF Member States and Cooperating States, to members of the World Meteorological Organization and to business customers. Access was subject to a series of custom licenses and high fees.

Read more …

ECMWF weather data soon open to the public [11st part]

Created in 1975 at the initiative of members of the European Union, the European Center for Medium-Term Meteorological Forecasting is an independent intergovernmental organization with, to date, is located in Reading, England. ECMWF is funded by 22 member states and 12 associated states. It employs nearly 350 people, and its supercomputer equipment is one of the largest in Europe. For about fifteen years, ECMWF forecasts tend to be among the most accurate in the world, according to verification data from the World Meteorological Organization (WMO). ECMWF is currently headed by French meteorologist Florence Rabier, who worked at the local Meteorological Office of Météo-France.

But, since the advent of Brexit, the situation has changed. UK no longer part of the EU, CEPMMET must move to a European country, and this could generate, for weather data users, rather consequences… positives ! Read more …

Share GRIB files with Air Share

You are more likely to have adopted the Iridium GO! for its easy way to request GRIB files, directly from Weather4D and some other applications. But some also want to transfer these files to PC to import them into Windows software (as you know, nobody is perfect !). An easy solution is available : the messaging app Air Share, supported by either iOS and Android (¹). Read more …