Alternative weather models

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 the meteorological services, all countries included. Applications like XyGrib, LuckGrib, SailGrib, Weather4D and other, offer a selection of atmospheric and oceanic models, up to 25 weather models and 15 wave and current models for Weather4D, nearly fifty models with LuckGrib, for example. But there are always others that can usefully complement the standard offerings of these applications..

Just for Western Europe, several dozen high-resolution models are available for download, freely accessible, and in a format compatible with the majority of applications. There are now two formats used by weather services : GRIB1 and GRIB2 (¹). This last, enriched, is still only compatible with professional software or displays. It is sometimes necessary that the GRIB2 format be converted to GRIB1 in order to be recognized by applications (²).

Although Europe is already well covered by the best-known high-resolution models, as ARPEGE and AROME from Météo-France and ICON EU from Deutscher Wetterdienst, here are some examples of commonly used and easily accessible models (³).

NORTH EUROPE

  • HARMONY

(HIRLAM ALADIN Research on Mesoscale Operational NWP in Euromed), is produced by the Royal Netherlands Meteorological Institute (KNMI). This model is part of the European HIRLAM program (High Resolution Limited Area Model), managed by several European meteorological institutes. The HARMONIE model covers Europe with a resolution of 0.045 ° (5 km), up to 48 hours, updated twice a day (00,12UTC).

The HARMONIE-AROME Cy40 model covers localized areas within 48 hours at high resolution of 0.025 ° (2,5km) in one hour steps, updated 4 times a day (00, 06, 12, 18UTC) available approximately 5 hours later in GRIB format. The KNMI makes the GRIB files of the Harmony model available free of charge on its data platform in GRIB2 format. GRIB2 files are converted to GRIB1 format and uploaded to the website Euros Sailing of the University of Twente Sailing Club (Netherlands).

In total 8 areas are covered from Dover Strait to eastern Denmark. The data provided are : wind at 10m, gusts, atmospheric pressure at sea level, temperature at 2m, relative humidity, precipitation.

  • Yr – NMI

The’Norwegian Meteorological Institute (Meteorological Institute) offers on its dissemination websiteYr.no a list of GRIB files covering the Norwegian coast in GRIB1 format : wind, currents and waves. The wind files have a variable resolution depending on the area, by 1 updated four times a day (03, 09, 15, 21 UTC). Waves have a variable resolution depending on the area, by 1 hour updated twice a day (06, 18 UTC), the currents have a variable resolution depending on the area 1 hour updated once a day (00 UTC) . All forecasts have a range up to 66 hours.

The GRIBs are unfortunately quite poor. The wind files provide only the average wind data at 10m, waves the significant height, currents speed and direction

  • ICON-D2

ICON-D2 is a high resolution model produced by the Deutscher Wetterdienst (DWD) in Germany. This model replaced COSMO-D2 in February 2021. Very high resolution of 0.02 ° (2,2 km) on an icosahedral grid, by 1 hour steps up to 48 hours. Updates every 3 hours start around 2:40 a.m., 5H40, 8H40, 11H40, 14H40, 17H40, 20h40 and 23:40. 8 areas are offered from Dover Strait to Baltic entrance.

The GRIBs are posted online and available on the dedicated page of the website OpenSkiron (). The data provided are : wind at 10m, gusts, atmospheric pressure at sea level, temperature at 2m, cloud coverage, relative humidity, precipitation, air temperature, CAPE. To this are added forecasts of swell and waves due to the wind (height, period and direction). Warning : these files are GRIB2 format, incompatible with Weather4D.

SOUTHERN EUROPE – MEDITERRANEAN

  • OpenWRF

OpenSkiron () offers 10 areas covering Western Europe and the Mediterranean. Each zone is associated with a WRF model at 0.01 ° (± 12 km) by 3 hours step up to 5 days, updated 2 times a day (00, 12UTC) available around 5 hours and a half later.
Each of these areas contains one or more high resolution 0.036 ° WRF models (4 km) by 1 hour steps up to 24 hours, updated 1 time a day and available at variable times specified on dedicated page. Not less than 32 areas are proposed with this resolution.

Data provided are GRIB1 format : wind at 10m, gusts, atmospheric pressure at sea level, temperature at 2m, cloud coverage, relative humidity, precipitation, snow depth, air temperature, CAPE. To this are added forecasts of swell and waves due to the wind (height, period and direction), and current forecasts (speed and direction).

OpenWRF Gribs are produced using the EMS-WRF model, from NOAA, with the last kernel of the non-hydrostatic mesoscale model ARW. The advantage of these forecasts is that they are produced by a high resolution non-hydrostatic regional model which models local weather phenomena well, while global models such as the GFS are hydrostatic models which, by definition, model the synoptic time scale better than regional and local meteorological phenomena. Wave data are from the model WAM (WAve Model) coupled with ECMWF atmospheric model and currents from Mercator Ocean.

In conclusion, these complementary models can help refine forecasts in certain areas where high-resolution models may be lacking. This short presentation is of course not exhaustive, and there are many other models specific to various regions of the globe.

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(¹) See Glossary
(²) Files with .grb extensions / .grb.bz / .grb.bz2 are generally compatible.
(³) It should be remembered that the leading European model IFS from CEPMMT (ECMWF) is still only accessible at prices incompatible with the wallet of individuals (see Related Articles below). 
() OpenSkiron is an Israel-based website administered voluntarily and generously by David Gal.
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Related Articles :
ECMWF weather data soon open to the public [1st part]
ECMWF weather data soon open to the public [2rd part]
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2 Replies to “Alternative weather models”

  1. Being able to read and use (not just charge) OpenSkiron files in Weather4D Routing and Navigation do you need to have subscribed / renewed the weather subscription ? Thank you

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