Weather Model (HARMONIE) for Netherlands, Europe and Caribbean

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 forecasts. Since 2024, the new version HARMONIE Cy43 has been in use, produced by the United Weather Centres-West (UWC-West) partnership. The weather model produces weather forecasts for such things as temperature, wind, air pressure and precipitation. It calculates the parameters up to 60 hours ahead, with a resolution of 1 hour. HARMONIE is issued generically for the Netherlands, Europe and a Caribbean domain.

Goal HARMONIE

Weather forecasts are calculated by computer models that describe the development of the real atmosphere using 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 competencies 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 scale but can have serious consequences, for example, extreme precipitation such as cloudbursts and rapidly changing low-level thunderstorms.

HARMONIE Cy43 technical documentation

On June 20, 2024, KNMI began operational runs of HARMONIE from Cycle 43 at UWC-West after a one-year test period. We provide datasets for three areas: The Netherlands, Europe and the Caribbean. The Dutch and European domains are cutouts of the DINI domain (Denmark, Ireland, Netherlands, Iceland), which was created from the collaboration within UWC-West. A separate run is made for the Caribbean, which is expanded to include Suriname compared to the previous version. This run also includes the domains for both the Windward and Leeward Islands.

These datasets are only available for the entire domain. We do not, in accordance with our legal framework, offer cutouts for specific locations or parameters.

Data set (on KDP)	Domin	Run	Max. vertical height	Parameters
HARMONIE Cy43 P1	Netherlands	Deterministic	300	Meteorological
HARMONIE Cy43 P2a	Netherlands	Ensemble	10	Meteorological
HARMONIE Cy43 P2b	Netherlands	Ensemble	300	Renewal energie
HARMONIE Cy43 P3	Europe	Deterministic	300	Meteorological
HARMONIE Cy43 P4a	Europe	Ensemble	10	Meteorological
HARMONIE Cy43 P4b	Europe	Ensemble	300	Renewal energie
HARMONIE Cy43 P5	Europe	Deterministic	550	Selection
HARMONIE Cy43 BES	Caribbean	Deterministic	1000	Meteorological
HARMONIE Cy43 L20 (soon available)	Europe	Deterministic	10	North Sea applications

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:

HA43_TTT_yyyymmddhh_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
yyyymmddhh 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

Dutch and European (DINI) domain

The Dutch domain is the green outline on the left figure below. It has the full HARMONIE resolution (~2x2 km). The grid is a regular lat-lon grid with a grid spacing of about 2 km (longitude: 0.01 degrees; latitude: 0.029 degrees).
The European domain is the blue outline on the left figure below and is the full domain of DINI. It is a rotated lat-lon grid with a reduced resolution of 0.05 degrees, with meteorological parameters available at normal altitudes (above the surface) and at pressure levels.

Illustration of UWCW domains of the Netherlands, Europe and Caribbean. — On the left is the DINI domain, with Europe (red) containing the 2.0 km lat-lon cutout around the Netherlands (green) and the 5.5 km rotated lat-lon cutout covering almost the entire area (blue). On the right is the Caribbean domain, with the entire domain (light blue) and the Leeward Islands (brown) and Windward Islands (gray)

Caribbean domain

The files in the Caribbean dataset are divided into BESS, BOV and BEN. BESS covers the entire Caribbean region, BOV is the domain for the Dutch Windward Islands, and the BEN is the domain for the Dutch Leeward Islands. The Caribbean domain now includes Suriname and provides broader coverage for the region, and is the bright green outline on the right figure above. The coordinates of the new domain are from -3 to 24.45 degrees (latitude) and from -79.5 to -42.55 degrees (longitude) in 0.05-degree increments. This results in a grid with 740 points in latitude and 550 points in longitude.

Ensemble data are processed in batches of 5 members (MBR). Each batch uses the latest ECMWF analysis as input.

Member 1 to 5 at hour 1
Member 6 to 10 at hour 2
Member 11 to 15 at hour 3
Member 16 to 20 at hour 4
Member 21 to 25 at hour 5
Member 26 to 30 at hour 6

This setup ensures that 5 ensemble members are generated every hour, each starting at that specific hour. Unlike traditional ensembles where a full set is started at a single time, we now continuously generate subsets, creating a rolling ensemble prediction.

To have a full set of ensemble data like ECMWF, it is necessary to clip 5 to 0 hours at the beginning of the forecast horizon and add 0 to 5 hours at the end of the forecast horizon (See image below).

Explanation ensemblemembers in HARMONIE — Visual presentation ensemble members in HARMONIE. Member 0 is in every run, the other members have an off-set in time when run. To have to have a full ensemble, users could combine them with a delay to a full ensamble of 30 members with a total weather forecast of 54 hours.

Special considerations for accumulated parameters

To avoid overestimates, it is necessary, for accumulated parameters such as precipitation, to subtract precipitation from the first shared hour of the ensemble members. Each batch of ensemble members starts at a different hour. Careful adjustment is thus required to ensure accurate values for the accumulated data. Other parameters, such as temperature and wind, can be used as they are for each ensemble member without further adjustment.

HARMONIE data is stored in the GRIB1 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. An overview of GRIB codes that fit the KNMI data can be found in the tables below.

Here is a summary of the GRIB codes for HARMONIE Cy43 P1. Code is the indicatorOfParameter variable, LevelType is found as indicatorOfTypeOfLevel, and TRI stands for timeRangeIndicator. For LevelType and TRI, at the bottom of the page is an explanation of what their numbers represent.

Table with GRIB codes for data set HARMONIE Cy43 P1
Code	Abbreviation	Parameter description	Unit	Leveltype	Level	TRI
1	PMSL	Pressure altitude above mean sea level	Pa	103	0	0
1	PSRF	Pressure height above ground	Pa	105	0	0
6	GP	Geopotential	m2 s-2	105	0	0
11	TMP	Temperature	K	100	100, 200, 300	0
11	TMP	Temperature	K	105	0, 2, 50, 100, 200, 300	0
11	ISBA	Temperature of nature tile (per 18-11-24)	K	105	800(0cm), 801(-7cm), 802(-50cm)	0
17	DPT	Dew-point temperature	K	105	2	0
20	VIS	Visibility	m	105	0	0
33	UGRD	u-component of wind	m s-1	100	100, 200, 300	0
33	UGRD	u-component of wind	m s-1	105	10, 50, 100, 200, 300	0
34	VGRD	v-component of wind	m s-1	100	100, 200, 300	0
34	VGRD	v-component of wind	m s-1	105	10, 50, 100, 200, 300	0
52	RH	Relative humidity	%	105	2	0
61	APCP	Total precipitation	kg m-2	105	0	4
65	WEASD	Water equivalent of accumulated snow depth	kg m-2	105	0	0
66	SD	Snow depth	m	105	0	0
67	MIXHT	Mixed layer depth	m	105	0	0
71	TCDC	Total cloud cover	%	105	0	0
73	LCDC	Low cloud cover	%	105	0	0
74	MCDC	Medium cloud cover	%	105	0	0
75	HCDC	High cloud cover	%	105	0	0
81	LAND	Landcover	Proportion	105	0	0
111	NSWRS	Net short-wave radiation flux (surface)	W m-2	105	0	4
112	NLWRS	Net long-wave radiation flux (surface)	W m-2	105	0	4
117	GRAD	Global radiation flux	W m-2	105	0	4
122	SHTFL	Sensible heat flux	W m-2	105	0	4
132	LHTFL	Latent heat flux through evaporation	W m-2	105	0	4
162	CSULF	U-momentum of gusts out of the model	m s-1	105	10	2
163	CSDLF	V-momentum of gusts out of the model	m s-1	105	10	2
181	LPSX	(Cumulative sum) Rain	kg m-2	105	0	4
181	LPSX	Rain	kg m-2	105	0	0
184	HGTY	(Cumulative sum) Snow	kg m-2	105	0	4
184	HGTY	Snow	kg m-2	105	0	0
186	ICNG	Cloud base	m	200	0	0
201	ICWAT	(Cumulative sum) Graupel	kg m-2	105	0	4
201	ICWAT	Graupel	kg m-2	105	0	0
201	ICWAT	(Column integrated) Graupel	kg m-2	200	0	0

Here is a summary of the GRIB codes for HARMONIE Cy43 P3. Code is the indicatorOfParameter variable, LevelType is found as indicatorOfTypeOfLevel, and TRI stands for timeRangeIndicator. For LevelType and TRI, at the bottom of the page is an explanation of what their numbers represent.

Table with GRIB codes for data set HARMONIE Cy43 P3
Code	Abbreviation	Parameter description	Unit	Leveltype	Level	TRI
1	PMSL	Pressure altitude above mean sea level	Pa	103	0	0
1	PSRF	Pressure height above ground	Pa	105	0	0
6	GP	Geopotential	m2 s-2	105	0	0
11	TMP	Temperature	K	100	200, 300, 500, 700, 850, 925	0
11	TMP	Temperature	K	105	0, 2, 50, 100, 200, 300	0
17	DPT	Dew-point temperature	K	105	2	0
20	VIS	Visibility	m	105	0	0
33	UGRD	u-component of wind	m s-1	100	200, 300, 500, 700, 850, 925	0
33	UGRD	u-component of wind	m s-1	105	10, 50, 100, 200, 300	0
34	VGRD	v-component of wind	m s-1	100	200, 300, 500, 700, 850, 925	0
34	VGRD	v-component of wind	m s-1	105	10, 50, 100, 200, 300	0
52	RH	Relative humidity	%	100	300, 500, 700, 850, 925	0
52	RH	Relative humidity	%	105	2	0
61	APCP	Total precipitation	kg m-2	105	0	4
65	WEASD	Water equivalent of accumulated snow depth	kg m-2	105	0	0
66	SD	Snow depth	m	105	0	0
67	MIXHT	Mixed layer depth	m	105	0	0
71	TCDC	Total cloud cover	%	105	0	0
73	LCDC	Low cloud cover	%	105	0	0
74	MCDC	Medium cloud cover	%	105	0	0
75	HCDC	High cloud cover	%	105	0	0
81	LAND	Landcover	Proportion	105	0	0
111	NSWRS	Net short-wave radiation flux (surface)	W m-2	105	0	4
112	NLWRS	Net long-wave radiation flux (surface)	W m-2	105	0	4
117	GRAD	Global radiation flux	W m-2	105	0	4
122	SHTFL	Sensible heat flux	W m-2	105	0	4
132	LHTFL	Latent heat flux through evaporation	W m-2	105	0	4
162	CSULF	U-momentum of gusts out of the model	m s-1	105	10	2
163	CSDLF	V-momentum of gusts out of the model	m s-1	105	10	2
181	LPSX	(Cumulative sum) Rain	kg m-2	105	0	0
181	LPSX	Rain	kg m-2	105	0	4
184	HGTY	(Cumulative sum) Snow	kg m-2	105	0	0
184	HGTY	Snow	kg m-2	105	0	4
186	ICNG	Cloud base	m	200	0	0
201	ICWAT	(Cumulative sum) Graupel	kg m-2	200	0	0
201	ICWAT	Graupel	kg m-2	105	0	0
201	ICWAT	Graupel	kg m-2	105	0	4

Here is a summary of the GRIB codes for HARMONIE Cy43 P5. Code is the indicatorOfParameter variable, LevelType is found as indicatorOfTypeOfLevel, and TRI stands for timeRangeIndicator. For LevelType and TRI, at the bottom of the page is an explanation of what their numbers represent.

Table with GRIB codes for data set HARMONIE Cy43 P5
Code	Abbreviation	Parameter description	Unit	Leveltype	Level
1	PSRF	Pressure height above ground	Pa	105	0
6	GP	Geopotential	m2 s-2	105	0
11	TMP	Temperature	K	105	0
11	TMP	Temperature	K	109	1-90
33	UGRD	u-component of wind	m s-1	109	1-90
34	VGRD	v-component of wind	m s-1	109	1-90
51	SPFH	Specified humidity	kg kg-1	109	1-90

HARMONIE Cy43 P2a/P4a

Here is a summary of the GRIB codes for HARMONIE Cy43 P2a/P4a. Both HARMONIE Cy43 P2a and HARMONIE Cy43 P4a contain the same set of variables. The difference is that P2a is for the Dutch domain, and P4a is the entire DINI domain at a lower resolution. Code is the indicatorOfParameter variable, LevelType is found as indicatorOfTypeOfLevel, and TRI stands for timeRangeIndicator. For LevelType and TRI, at the bottom of the page is an explanation of what their numbers represent.

Table with GRIB codes for data set HARMONIE Cy4 P2a/P4a
Code	Abbreviation	Parameter description	Unit	Leveltype	Level	TRI
1	PMSL	Pressure altitude above mean sea level	Pa	103	0	0
11	TMP	Temperature	K	105	2	0
20	VIS	Visibility	m	105	0	0
33	UGRD	u-component of wind	m s-1	105	10, 50	0
34	VGRD	v-component of wind	m s-1	105	10, 50	0
52	RH	Relative humidity	%	105	2	0
65	WEASD	Water equivalent of accumulated snow depth	kg m-2	105	0	0
71	TCDC	Total cloud cover	%	105	0	0
73	LCDC	Low cloud cover	%	105	0	0
74	MCDC	Medium cloud cover	%	105	0	0
75	HCDC	High cloud cover	%	105	0	0
162	CSULF	U-momentum of gusts out of the model	m s-1	105	10	2
163	CSDLF	V-momentum of gusts out of the model	m s-1	105	10	2
181	LPSX	Rain	kg m-2	105	0	4
184	HGTY	(Cumulative sum) Snow	kg m-2	105	0	4
186	ICNG	Cloud base	m	200	0	0
201	ICWAT	(Cumulative sum) Graupel	kg m-2	105	0	4
209	MIXLY	Lightning	-	200	0	0

HARMONIE Cy43 P2b/P4b

Here is a summary of the GRIB codes for HARMONIE Cy43 P2b/P4b. Both HARMONIE Cy43 P2b and HARMONIE Cy43 P4b contain the same set of variables. The difference is that P2b is for the Dutch domain, and P4b is the entire DINI domain at a lower resolution. Code is the indicatorOfParameter variable, LevelType is found as indicatorOfTypeOfLevel, and TRI stands for timeRangeIndicator. For LevelType and TRI, at the bottom of the page is an explanation of what their numbers represent.

Table with GRIB codes for data set HARMONIE Cy43 P2b/P4b
Code	Abbreviation	Parameter description	Unit	Leveltype	Level	TRI
33	UGRD	u-component of wind	m s-1	105	10, 50, 100, 200, 300	0
34	VGRD	v-component of wind	m s-1	105	10, 50, 100, 200, 300	0
71	TCDC	Total cloud cover	%	105	0	0
117	GRAD	Global radiation flux	W m-2	105	0	4

HARMONIE Cy43 BESS

Here is a summary of the GRIB codes for HARMONIE Cy43 BESS. Code is the indicatorOfParameter variable, LevelType is found as indicatorOfTypeOfLevel, and TRI stands for timeRangeIndicator. For LevelType and TRI, at the bottom of the page is an explanation of what their numbers represent.

Table with GRIB codes for data set HARMONIE Cy43 BESS
Code	Abbreviation	Parameter description	Unit	Leveltype	Level	TRI
1	PMSL	Pressure altitude above mean sea level	Pa	103	0	0
6	GP	Geopotential	m2 s-2	100	500	0
11	TMP	Temperature	K	100	500	0
11	TMP	Temperature	K	105	2	0
17	DPT	Dew-point temperature	K	105	2	0
33	UGRD	u-component of wind	m s-1	100	200, 500, 700, 850, 925	0
33	UGRD	u-component of wind	m s-1	105	10	0
34	VGRD	v-component of wind	m s-1	100	200, 500, 700, 850, 925	0
34	VGRD	v-component of wind	m s-1	105	10	0
73	LCDC	Low cloud cover	%	105	0	0
74	MCDC	Medium cloud cover	%	105	0	0
75	HCDC	High cloud cover	%	105	0	0
116	SWAVR	Short-wave radiation flux	W m-2	105	0	0, 4
117	GRAD	Global radiation flux	W m-2	105	0	4
160	CSUSF	CAPE	J kg-1	105	0	0
161	CSDSF	AROME hail diagnostic	%	105	10	0
162	CSULF	U-momentum of gusts out of the model	m s-1	105	10	2
163	CSDLF	V-momentum of gusts out of the model	m s-1	105	10	2
165	CFNLF	Convective inhibition (CIN)	J kg-1	105	0	0
181	LPSX	(Cumulative sum) Rain	kg m-2	105	0	0, 4
184	HGTY	(Cumulative sum) Snow	kg m-2	105	0	0, 4
187	LTNG	Cloud top	m	200	0	0
201	ICWAT	(Cumulative sum) Graupel	kg m-2	105	0	0, 4

HARMONIE Cy43 BOV/BEN

Here is a summary of the GRIB codes for HARMONIE Cy43 BOV/BEN.

Table with GRIB codes for data set HARMONIE Cy43 BOV/BEN
Code	Abbreviation	Parameter description	Unit	Leveltype	Level	TRI
1	PMSL	Pressure altitude above mean sea level	Pa	103	0	0
11	TMP	Temperature	K	105	2	0
17	DPT	Dew-point temperature	K	105	2	0
33	UGRD	u-component of wind	m s-1	105	10	0
34	VGRD	v-component of wind	m s-1	105	10	0
51	SPFH	Specific humidity	kg kg-1	105	2	0
52	RH	Relative humidity	%	105	100, 250, 500, 750, 1000	0
71	TCDC	Total cloud cover	%	105	0	0
73	LCDC	Low cloud cover	%	105	0	0
74	MCDC	Medium cloud cover	%	105	0	0
75	HCDC	High cloud cover	%	105	0	0
76	CWAT	Cloud water	kg m-2	109	65	0
116	SWAVR	Short-wave radiation flux	W m-2	105	0	0, 4
117	GRAD	Global radiation flux	W m-2	105	0	4
161	CSDSF	AROME hail diagnostic	%	105	0	0
162	CSULF	U-momentum of gusts out of the model	m s-1	105	10	2
163	CSDLF	V-momentum of gusts out of the model	m s-1	105	10	2
181	LPSX	(Cumulative sum) Rain	kg m-2	105	0	0, 4
181	LPSX	Rain	kg m-2	109	65	0
184	HGTY	(Cumulative sum) Snow	kg m-2	105	0	0, 4
201	ICWAT	(Cumulative sum) Graupel	kg m-2	105	0	0, 4

Here is a summary of the GRIB codes for HARMONIE Cy43 L20. Code is the indicatorOfParameter variable, LevelType is found as indicatorOfTypeOfLevel, and TRI stands for timeRangeIndicator. For LevelType and TRI, at the bottom of the page is an explanation of what their numbers represent.

Table with GRIB codes for data set HARMONIE Cy43 L20
Code	Abbreviation	Parameter description	Unit	Leveltype	Level	TRI
1	PMSL	Pressure altitude above mean sea level	Pa	103	0	0
11	TMP	Temperature	K	105	2	0
17	DPT	Dew-point temperature	K	105	2	0
33	UGRD	u-component of wind	m s-1	105	10	0
34	VGRD	v-component of wind	m s-1	105	10	0
61	APCP	Total precipitation	kg m-2	105	0	4
71	TCDC	Total cloud cover	%	105	0	0
81	LAND	Landcover	Proportion	105	0	0
115	LWAVR	Long-wave radiation flux	W m-2	105	0	4
117	GRAD	Global radiation flux	W m-2	105	0	4
124	UFLX	Momentum flux, u-component	N m-2	105	760(sea) / 770 (lakes)	0
125	VFLX	Momentum flux, v-component	N m-2	105	760(sea) / 770 (lakes)	0

LevelType

Table with definitions for leveltype
Level type	WMO/HIRLAM type definition	Units
100	Isobaric level	hPa
103	Specified altitude above mean sea level	Altitude in m
105	Specified height above ground	Altitude in m
109	Hybrid level
200	Entire atmosphere (considered as a single layer)

TRI (TimeRangeIndicator)

Table explaining TRI
Time Range Indicator	Range
0	Instant
2	Accumulated over limited period
4	Accumulated over entire forecast period

Weather Model (HARMONIE) for Netherlands, Europe and Caribbean

Goal HARMONIE

HARMONIE Cy43 technical documentation

Overview of available data sets

General technical specifications

Ensemble members

GRIB

HARMONIE Cy43 P1

HARMONIE Cy43 P3

HARMONIE Cy43 P5

HARMONIE Cy43 P2/P4

HARMONIE Cy43 BES (BESS/BEN/BOV)

HARMONIE Cy43 L20

Explanation LevelType and TRI