Technical documentation

General documentation Harmonie

KNMI uses and co-develops HARMONIE. This weather model is used by European meteorological services such as KNMI, for high-resolution short-range numerical weather prediction. Since april 2026 the testing phase started for the new Harmonie 46 model. The weather model produces weather forecasts for parameters like temperature, wind, air pressure and precipitation. It calculates the parameters up to 60 hours ahead, with a resolution of 1 hour for many parameters and 15 minutes for a few selected parameters. HARMONIE is issued for the Netherlands, Europe (postprocessed products from the one model run) and a Caribbean domain (different model run).

Goal Harmonie

Weather forecasts are calculated by numerical models that describe the development of the real atmosphere using physical and mathematical equations. HARMONIE is mainly developed by a European consortium for short-term weather forecasts. Within this consortium, each national weather service has its own national responsibilities and corresponding competences in safety, including warnings, preparedness and defense. KNMI's HARMONIE weather model is therefore also available in three different versions covering the geographical area of the Netherlands, Europe and the Caribbean. The model focuses on events that occur on a small scales that can have serious consequences, for example, extreme precipitation such as cloudbursts and thunderstorms that can bring rapidly changing weather and local extremes.

Filename and times

A new weather forecast is available every hour. The files are compressed into .tar. Extracted, the file names follow the following convention:

HA46_TTT_YYYMMDDhhmm_lllll_GB

  • TTT is for file type: N20 is the Dutch domain, N55 is the DINI/EU domain, L20 is the original resolution DINI/EU domain
  • YYYYMMDDhhmm is the date and time of the forecast
  • lllll is the current time span in hours within the prediction of time intervals of +00h (+1h) +60h
GRIB data format

HARMONIE data is stored in the GRIB format, a standard from the World Meterological Organization (WMO). Therefore, we recommend using a grib decoder that fits the grib code table associated with the corresponding grib files. A decoder that fits the KNMI HARMONIE files is an open source package ecCODES which can be downloaded from the ECMWF. This package can decode GRIB1 and GRIB2 data. An overview of GRIB codes that fit the KNMI data can be found in the table under "What variables are in this dataset", the full GRIB2 definitions can be found here.

Contents of P1

The P1 package contains the meteorological parameters for the Netherlands and its direct surroundings, at approximately the resolution of the original grid, but reprojected to a regular lat-lon grid of 0.018° in the North-South direction and 0.029° in the West-East direction. All parameters are on height levels at or close to the surface or in the bottom 300 metres of the atmosphere.

Differences with Harmonie 43

These are the changes compared to Harmonie 43. HARMONIE 43 is available in GRIB1 format, HARMONIE 46 is delivered in GRIB2 format. Note that all parameters of HARMONIE 43 are also available for HARMONIE 46, with the exception of the nature tile soil temperature parameters. A verification report detailing the differences and improvements of Harmonie 46 compared to Harmonie 43 can be found here.

What variables are in this dataset

Here is a summary of the GRIB codes for HARMONIE Cy43 P1 and HARMONIE CY46 P1. The codes that are used are the indicatorOfParameter variable, LevelType is found as indicatorOfTypeOfLevel, and TRI stands for timeRangeIndicator.

The GRIB2 codes that can be used for decoding HARMONIE Cy46 P1 are dis (discipline), pCt (parameterCategory), pNb (parameterNumber), pDTN (productDefinitionTemplateNumber) and tOSP (typeOfStatisticalProcessing). If there is no specific processing tOSP will show a "X", if there is processing being done, then there will be a pDTB number higher than 0. A tOSP of 1 means the parameter is accumulated over the entire forecast, a tOSP of 2 means the accumulation or maximum is determined over the past hour.

Table with GRIB codes for data set HARMONIE Cy43 P1, HARMONIE Cy46 codes behind it.

Code Abbreviation Parameter description Unit Leveltype Level TRI GRIB2 dis pCt pNb typeOfLevel pDTN tOSP
1 PMSL Pressure altitude above mean sea level Pa 103 0 0 0 3 0 meanSea 0 X
1 PSRF Pressure height above ground Pa 105 0 0 0 3 0 surface 0 X
6 GP Geopotential m2 s-2 105 0 0 0 3 4 surface 0 X
11 TMP Temperature K 105 0 0 0 0 0 surface 0 X
11 TMP Temperature K 105 2, 50, 100, 200, 300 0 0 0 0 heightAboveGround 0 X
11 ISBA Temperature of nature tile (per 18-11-24) K 105 800(0cm), 801(-7cm), 802(-50cm) 0 X X X X X X
17 DPT Dew-point temperature K 105 2 0 0 0 6 heightAboveGround 0 X
20 VIS Visibility m 105 0 0 0 19 0 heightAboveGround 0 X
33 UGRD u-component of wind m s-1 105 10, 50, 100, 200, 300 0 0 2 2 heightAboveGround 0 X
34 VGRD v-component of wind m s-1 105 10, 50, 100, 200, 300 0 0 2 3 heightAboveGround 0 X
52 RH Relative humidity % 105 2 0 0 1 1 heightAboveGround 0 X
61 APCP Total precipitation kg m-2 105 0 4 0 1 52 surface 8 1
65 WEASD Water equivalent of accumulated snow depth kg m-2 105 0 0 0 1 60 surface 0 X
66 SD Snow depth m 105 0 0 0 1 11 surface 0 X
67 MIXHT Mixed layer depth m 105 0 0 0 3 18 surface 0 X
71 TCDC Total cloud cover % 105 0 0 0 6 1 entireAtmosphere 0 X
73 LCDC Low cloud cover % 105 0 0 0 6 3 lowCloudLayer 0 X
74 MCDC Medium cloud cover % 105 0 0 0 6 4 mediumCloudLayer 0 X
75 HCDC High cloud cover % 105 0 0 0 6 5 highCloudLayer 0 X
81 LAND Landcover Proportion 105 0 0 2 0 0 surface 0 X
111 NSWRS Net short-wave radiation flux (surface) J m-2 105 0 4 0 4 9 surface 8 1
112 NLWRS Net long-wave radiation flux (surface) J m-2 105 0 4 0 5 5 surface 8 1
117 GRAD Global radiation flux J m-2 105 0 4 0 4 7 surface 8 1
122 SHTFL Sensible heat net flux J m-2 105 0 4 0 0 11 surface 8 1
132 LHTFL Latent heat net flux J m-2 105 0 4 0 0 10 surface 8 1
162 CSULF U-momentum of gusts out of the model m s-1 105 10 2 0 2 23 heightAboveGround 8 2
163 CSDLF V-momentum of gusts out of the model m s-1 105 10 2 0 2 24 heightAboveGround 8 2
181 LPSX (Cumulative sum) Rain kg m-2 105 0 4 0 1 65 surface 8 1
181 LPSX Rain kg m-2 105 0 0 0 1 65 surface 0 X
184 HGTY (Cumulative sum) Snow kg m-2 105 0 4 0 1 66 surface 8 1
184 HGTY Snow kg m-2 105 0 0 0 1 66 surface 0 X
186 ICNG Cloud base m 200 0 0 0 6 11 cloudBase 0 X
201 ICWAT (Cumulative sum) Graupel kg m-2 105 0 4 0 1 75 surface 8 1
201 ICWAT Graupel kg m-2 105 0 0 0 1 75 surface 0 X
201 ICWAT (Column integrated) Graupel kg m-2 200 0 0 0 1 74 entireAtmosphere 8 2