Label : weather

Alternative weather models [Update]

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[Update 29 July 2022]

For several years, forecast files in GRIB format have been widely used in meteorological applications.. The majority of forecast models have been made freely available by meteorological services, all countries included. Apps like XyGrib, LuckGrib, SailGrib, Weather4D and others, offer a selection of atmospheric and oceanic models, up to 60 Weather Models, Waves and currents for Weather4D, more than thirty models with LuckGrib, in example. But there are always others that can usefully complement the standard offerings of these applications. Read more …

Predict storms with Weather4D

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

Convective Available Potential Energy, in French : Energie potentielle de convection disponible. Behind this obscure acronym hides a powerful storm forecasting tool. CAPE is measured in Joules per kilogram of air (J/Kg) and defines the vertical buoyancy 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 …

Reading : “Clouds and other meteors” Météo-France

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In an article updated in August 2020 (¹), I described nautical works in digital format that can be usefully saved on iPad in the Apple Books application. Among them, I mentioned the Météo-France books available in PDF format for free download from their documentary portal.

In the "Courses and Manuals" section of this site, a new book can be downloaded, Published in 2020, entitled " Meteorological Observations and Measurements – Volume 1 / Clouds and other meteors ”, A wealth of information about clouds, and all associated weather phenomena, which are called "meteors" (²). Read more …

You said « Medicane » ?

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Many sailors who cross the "Big Blue" have known for ages that, if the navigation is relatively easy, the weather represents a particularly difficult constraint to deal. Indeed, if the coasts are mostly clean and the dangers very localized, if the tides are almost insignificant, if the currents are to be considered only in well defined areas, the major difficulty comes from a capricious meteorology, difficult to forecast, which can represent a real danger by its changing moods, sudden, even rough. Read more …

New major evolution of the GFS model

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

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

Sea state : interpret wave patterns

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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 FNMOC (Fleet Numerical Meteorology and Oceanography Center) of the US Navy, with a global model due to 7 days and resolution 1° (60NM), and a Europe model to 3 days and resolution 0.2° (12NM). Météo-France publish the models MFAUM (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)

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Friday 13 November will not be a lucky day for the Vendée Globe skippers 2020 (¹). They will have to negotiate the encounter with tropical storm "Theta" which crosses their course with average winds that can reach the 40 nodes and powerful bursts. Above all, the sea will be to be feared because, strongly crossed as they passed the centre of the low pressure system, Waves may exceed 6 meters and break in a chaotic way. Read more …

Routing : from game to reality

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On the second day of racing of this Vendée Globe 2020, we can say that the weather conditions that the skippers will experience on the descent towards the Doldrums will be particularly tough. After a departure in a damned weather, A first weak cold front passed without incident, The Solitaires will cross a second, much more violent front during the night and morning from Tuesday to Wednesday, for the group that went to the West, and in the evening for the group passed between the DST (¹) and Gallicia.

But these upcoming conditions are very different for Virtual Regatta players and For sailors… Read more …

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

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Source : The Parliament Mag par Umberto Modigliani, ECMWF Deputy Director of Forecasts, responsible, with the department director, continuous production of forecasts and relations with users.

Early October, the European Centre for Medium-Range Weather Forecasts (ECMWF) will take a big step forward by making hundreds of its forecast maps available to everyone free of charge.
The changes are part of a broader European initiative to make public sector data free and open, encourage innovation and support a thriving data-driven digital economy.

Thus far, full access to these forecast maps was restricted to the national meteorological and hydrological services of the Member States and the ECMWF Cooperating States, to members of the World Meteorological Organization and commercial customers. Access was subject to a series of customized licenses and high royalties.

Read more …