Catalog > ECMWF IFS ENS forecast, 15 day, 0.25 degree > Validation report

ECMWF IFS ENS forecast, 15 day, 0.25 degree validation report

This dataset validation report plots a sample of values from the ECMWF IFS ENS forecast, 15 day, 0.25 degree dataset over time and across space, comparing where possible to a previously validated reference dataset. It also reports the quantity of unavailable values and their associated timestamps. These analyses are one layer of a multi-layered dataset validation process we perform at dynamical.org and also provide users a preview of the dataset contents.

Report generation start time: 2026-06-03T02:20:46 UTC

Summary

This dataset has been reviewed and is ready for use. The one thing a user should know is that three variables start later than the rest of the archive (ECMWF added them to its open-data feed on later dates).

What looks good

Map geometry and coordinates are correct for every variable: global −180°→+180° longitude with east on the right, north at the top, and coastlines/topography landing at the expected locations (Antarctica, the Andes, the Himalayas, Greenland all appear where they should). The spatial snapshot for this run (init 2026-01-15, 24 h lead) is after every variable's start date, so the combined spatial figure shows real data for all 19 variables.
Value ranges and distributions are physically plausible and overlap the GEFS reference histograms for shared variables (temperature in °C, pressures in Pa, geopotential heights in m, winds in m/s, precipitation rate ~10⁻⁵ kg m⁻² s⁻¹). The MARS-sourced geopotential→geopotential-height conversion and the cloud-cover fraction→percent scaling both produce correct ranges.
Time series track the reference at short lead times and diverge at long lead times, which is the expected loss of forecast skill (this is a 15-day forecast compared against an analysis), not a data problem. Diurnal cycles of shortwave radiation and 2 m temperature are in phase with the reference, and surface pressure tracks GEFS closely at both sample points.
Accumulated variables deaccumulate cleanly (precipitation and the two radiation fluxes) — smooth diurnal radiation shapes, no negative spikes, no stuck values.
No quantization banding or sentinel values; high-precision fields (geopotential heights, pressures) are smooth.
Null fractions are zero everywhere except the documented coverage gaps in the notes below.

Review notes

Three variables begin later than the 2024-04-01 archive start, because ECMWF added them to its open-data feed on those dates. Forecasts initialized before these dates have these variables as unavailable (NaN): precipitation type (categorical_precipitation_type_surface) and 10 m wind gust (wind_gust_10m) start 2024-11-13; total cloud cover (total_cloud_cover_atmosphere) starts 2025-11-21. The null plots show a clean step at each start date (see nulls_total_cloud_cover_atmosphere.png). This run's randomly chosen time-series window (init 2025-06-27) predates the cloud-cover start, so cloud cover's temporal_* panel shows only the reference series — it is fully exercised in the spatial panel instead, and its availability step is confirmed in the null plot.
Very rare isolated NaNs in precipitation rate at later lead times. The source's cumulative precipitation should only increase, but GRIB2 packing precision occasionally makes it dip slightly between steps, producing a small negative deaccumulated rate. The deaccumulation step handles this with a threshold of −7×10⁻⁵ kg m⁻² s⁻¹: a negative rate above the threshold (a tiny non-physical decrease) is clamped to 0, while a rate more negative than the threshold is treated as genuinely invalid and written as NaN for that single grid cell / ensemble member / lead time. The isolated NaNs you see are therefore the cells whose decrease was larger than −7×10⁻⁵ kg m⁻² s⁻¹. In this run the sampled instance is at lead 78 h of the 2025-06-04 forecast, affecting a few ensemble members at both sample points (e.g. members 12, 22, 49 at 65.75°N/132°W); surrounding lead times are valid. It is a designed property of the deaccumulation, not a missing source file.

Datasets

Role	Name	ID	Version	URL
Validation	ECMWF IFS ENS forecast, 15 day, 0.25 degree	`ecmwf-ifs-ens-forecast-15-day-0-25-degree`	`v0.1.0`	`s3://us-west-2.opendata.source.coop/dynamical/ecmwf-ifs-ens-forecast-15-day-0-25-degree/v0.1.0.zarr`
Reference	NOAA GEFS analysis	`noaa-gefs-analysis`	`0.1.2`	`s3://dynamical-noaa-gefs/noaa-gefs-analysis/v0.1.2.icechunk/`

Run parameters

Parameter	Value
Validation dataset type	forecast
Validation time range	init_time 2024-04-01T00:00 → 2026-06-02T00:00
Reference time range	time 2000-01-01T00:00 → 2026-06-02T18:00
Time scope	full dataset
Point 1	lat=65.7500, lon=-132.0000
Point 2	lat=-49.5000, lon=133.2500
Ensemble member	1
Spatial comparison time	init=2026-01-15T00:00, lead=24h (reference at 2026-01-16T00:00)
Timeseries period	Forecast init_time: 2025-06-27T00:00

Combined plots

Unavailable values: combined_nulls.png
Spatial and distributions: combined_spatial.png
Time series: combined_temporal.png

Unavailable timestamps

Full list: unavailable_timestamps.txt

Variable	Point	Unavailable count	Total count	Unavailable %	Earliest unavailable	Latest unavailable
`categorical_precipitation_type_surface`	P1	226	3437655	0.01%	2024-04-01T00:00:00	2024-11-12T00:00:00
`categorical_precipitation_type_surface`	P2	226	3437655	0.01%	2024-04-01T00:00:00	2024-11-12T00:00:00
`precipitation_surface`	P1	1	3397212	0.00%	2025-06-04T00:00:00	2025-06-04T00:00:00
`precipitation_surface`	P2	1	3397212	0.00%	2025-06-04T00:00:00	2025-06-04T00:00:00
`total_cloud_cover_atmosphere`	P1	599	3437655	0.02%	2024-04-01T00:00:00	2025-11-20T00:00:00
`total_cloud_cover_atmosphere`	P2	599	3437655	0.02%	2024-04-01T00:00:00	2025-11-20T00:00:00
`wind_gust_10m`	P1	226	3397212	0.01%	2024-04-01T00:00:00	2024-11-12T00:00:00
`wind_gust_10m`	P2	226	3397212	0.01%	2024-04-01T00:00:00	2024-11-12T00:00:00

Per-variable details

`categorical_precipitation_type_surface`

Metadata

Field	Value
units	`1`
long_name	Precipitation type
short_name	ptype
standard_name	n/a
step_type	instant

Spatial — snapshot at init=2026-01-15T00:00, lead=24h (reference not available)

Source	min	mean	max
Validation	0	1.905	12

Temporal — period Forecast init_time: 2025-06-27T00:00

Source	min	mean	max
P1 Validation	0	0.2353	1
P2 Validation	0	0.9176	7

Nulls — P1: 979710/3437655 (226 unavailable (first: 2024-04-01T00:00:00, 2024-04-02T00:00:00, 2024-04-03T00:00:00 … last: 2024-11-10T00:00:00, 2024-11-11T00:00:00, 2024-11-12T00:00:00)); P2: 979710/3437655 (226 unavailable (first: 2024-04-01T00:00:00, 2024-04-02T00:00:00, 2024-04-03T00:00:00 … last: 2024-11-10T00:00:00, 2024-11-11T00:00:00, 2024-11-12T00:00:00))

$categorical_precipitation_type_surface — null fraction$

categorical_precipitation_type_surface — spatial comparison

categorical_precipitation_type_surface — time series comparison

`dew_point_temperature_2m`

Metadata

Field	Value
units	`degree_Celsius`
long_name	2 metre dewpoint temperature
short_name	2d
standard_name	dew_point_temperature
step_type	instant

Spatial — snapshot at init=2026-01-15T00:00, lead=24h (reference not available)

Source	min	mean	max
Validation	-54.5	0.0788	26.75

Temporal — period Forecast init_time: 2025-06-27T00:00

Source	min	mean	max
P1 Validation	3.375	10.38	15.94
P2 Validation	-2.188	4.047	7.75

Nulls — P1: 0/3437655 (none); P2: 0/3437655 (none)

$dew_point_temperature_2m — null fraction$

dew_point_temperature_2m — spatial comparison

dew_point_temperature_2m — time series comparison

`downward_long_wave_radiation_flux_surface`

Metadata

Field	Value
units	`W m-2`
long_name	Surface downward long-wave radiation flux
short_name	sdlwrf
standard_name	surface_downwelling_longwave_flux_in_air
step_type	avg

Spatial — snapshot at init=2026-01-15T00:00, lead=24h (reference at 2026-01-16T00:00)

Source	min	mean	max
Validation	95.5	296.3	456
Reference	97.5	288.4	486

Temporal — period Forecast init_time: 2025-06-27T00:00

Source	min	mean	max
P1 Validation	294	328	368
P1 Reference	268	313.9	362
P2 Validation	237	314.4	350
P2 Reference	238	296.7	350

Nulls — P1: 0/3397212 (none); P2: 0/3397212 (none)

$downward_long_wave_radiation_flux_surface — null fraction$

downward_long_wave_radiation_flux_surface — spatial comparison

downward_long_wave_radiation_flux_surface — time series comparison

`downward_short_wave_radiation_flux_surface`

Metadata

Field	Value
units	`W m-2`
long_name	Surface downward short-wave radiation flux
short_name	sdswrf
standard_name	surface_downwelling_shortwave_flux_in_air
step_type	avg

Spatial — snapshot at init=2026-01-15T00:00, lead=24h (reference at 2026-01-16T00:00)

Source	min	mean	max
Validation	0	178.5	1056
Reference	0	193.2	996

Temporal — period Forecast init_time: 2025-06-27T00:00

Source	min	mean	max
P1 Validation	3.406	233.5	632
P1 Reference	0	262.3	712
P2 Validation	0	24.8	168
P2 Reference	0	31.6	202

Nulls — P1: 0/3397212 (none); P2: 0/3397212 (none)

$downward_short_wave_radiation_flux_surface — null fraction$

downward_short_wave_radiation_flux_surface — spatial comparison

downward_short_wave_radiation_flux_surface — time series comparison

`geopotential_height_500hpa`

Metadata

Field	Value
units	`m`
long_name	Geopotential height
short_name	gh
standard_name	geopotential_height
step_type	instant

Spatial — snapshot at init=2026-01-15T00:00, lead=24h (reference at 2026-01-16T00:00)

Source	min	mean	max
Validation	4882	5505	5948
Reference	0	5497	5944

Temporal — period Forecast init_time: 2025-06-27T00:00

Source	min	mean	max
P1 Validation	5578	5650	5730
P1 Reference	5512	5613	5714
P2 Validation	5156	5455	5598
P2 Reference	5124	5384	5592

Nulls — P1: 0/3437655 (none); P2: 0/3437655 (none)

$geopotential_height_500hpa — null fraction$

geopotential_height_500hpa — spatial comparison

geopotential_height_500hpa — time series comparison

`geopotential_height_850hpa`

Metadata

Field	Value
units	`m`
long_name	Geopotential height
short_name	gh
standard_name	geopotential_height
step_type	instant

Spatial — snapshot at init=2026-01-15T00:00, lead=24h (reference not available)

Source	min	mean	max
Validation	1037	1395	1630

Temporal — period Forecast init_time: 2025-06-27T00:00

Source	min	mean	max
P1 Validation	1380	1451	1500
P2 Validation	1180	1391	1506

Nulls — P1: 0/3437655 (none); P2: 0/3437655 (none)

$geopotential_height_850hpa — null fraction$

geopotential_height_850hpa — spatial comparison

geopotential_height_850hpa — time series comparison

`geopotential_height_925hpa`

Metadata

Field	Value
units	`m`
long_name	Geopotential height
short_name	gh
standard_name	geopotential_height
step_type	instant

Spatial — snapshot at init=2026-01-15T00:00, lead=24h (reference not available)

Source	min	mean	max
Validation	362.4	710.5	973

Temporal — period Forecast init_time: 2025-06-27T00:00

Source	min	mean	max
P1 Validation	658	737.2	791
P2 Validation	495.8	714.2	827.5

Nulls — P1: 0/3437655 (none); P2: 0/3437655 (none)

$geopotential_height_925hpa — null fraction$

geopotential_height_925hpa — spatial comparison

geopotential_height_925hpa — time series comparison

`precipitation_surface`

Metadata

Field	Value
units	`kg m-2 s-1`
long_name	Precipitation rate
short_name	prate
standard_name	precipitation_flux
step_type	avg

Spatial — snapshot at init=2026-01-15T00:00, lead=24h (reference at 2026-01-16T00:00)

Source	min	mean	max
Validation	0	2.836e-05	0.009338
Reference	0	2.623e-05	0.005859

Temporal — period Forecast init_time: 2025-06-27T00:00

Source	mean	max
P1 Validation	3.378e-05	0.0004635
P1 Reference	2.041e-05	0.0003815
P2 Validation	2.115e-05	0.0002861
P2 Reference	2.88e-05	0.0003624

Nulls — P1: 3/3397212 (1 unavailable: 2025-06-04T00:00:00); P2: 1/3397212 (1 unavailable: 2025-06-04T00:00:00)

$precipitation_surface — null fraction$

precipitation_surface — spatial comparison

precipitation_surface — time series comparison

`pressure_reduced_to_mean_sea_level`

Metadata

Field	Value
units	`Pa`
long_name	Pressure reduced to MSL
short_name	prmsl
standard_name	air_pressure_at_mean_sea_level
step_type	instant

Spatial — snapshot at init=2026-01-15T00:00, lead=24h (reference at 2026-01-16T00:00)

Source	min	mean	max
Validation	9.677e+04	1.009e+05	1.056e+05
Reference	9.69e+04	1.01e+05	1.056e+05

Temporal — period Forecast init_time: 2025-06-27T00:00

Source	min	mean	max
P1 Validation	9.99e+04	1.009e+05	1.016e+05
P1 Reference	9.958e+04	1.008e+05	1.02e+05
P2 Validation	9.827e+04	1.01e+05	1.025e+05
P2 Reference	9.792e+04	1.004e+05	1.022e+05

Nulls — P1: 0/3437655 (none); P2: 0/3437655 (none)

$pressure_reduced_to_mean_sea_level — null fraction$

pressure_reduced_to_mean_sea_level — spatial comparison

pressure_reduced_to_mean_sea_level — time series comparison

`pressure_surface`

Metadata

Field	Value
units	`Pa`
long_name	Surface pressure
short_name	sp
standard_name	surface_air_pressure
step_type	instant

Spatial — snapshot at init=2026-01-15T00:00, lead=24h (reference at 2026-01-16T00:00)

Source	min	mean	max
Validation	4.827e+04	9.668e+04	1.07e+05
Reference	4.957e+04	9.667e+04	1.049e+05

Temporal — period Forecast init_time: 2025-06-27T00:00

Source	min	mean	max
P1 Validation	9.318e+04	9.408e+04	9.469e+04
P1 Reference	9.312e+04	9.426e+04	9.523e+04
P2 Validation	9.827e+04	1.01e+05	1.025e+05
P2 Reference	9.786e+04	1.004e+05	1.022e+05

Nulls — P1: 0/3437655 (none); P2: 0/3437655 (none)

$pressure_surface — null fraction$

pressure_surface — time series comparison

`temperature_2m`

Metadata

Field	Value
units	`degree_Celsius`
long_name	2 metre temperature
short_name	2t
standard_name	air_temperature
step_type	instant

Spatial — snapshot at init=2026-01-15T00:00, lead=24h (reference at 2026-01-16T00:00)

Source	min	mean	max
Validation	-50.75	4.12	40
Reference	-49.5	3.881	39.75

Temporal — period Forecast init_time: 2025-06-27T00:00

Source	min	mean	max
P1 Validation	9.312	16.33	24.5
P1 Reference	2.203	14.01	23.75
P2 Validation	3.625	6.783	9
P2 Reference	3.625	6.557	8.438

Nulls — P1: 0/3437655 (none); P2: 0/3437655 (none)

$temperature_2m — null fraction$

`temperature_850hpa`

Metadata

Field	Value
units	`degree_Celsius`
long_name	Temperature
short_name	t
standard_name	air_temperature
step_type	instant

Spatial — snapshot at init=2026-01-15T00:00, lead=24h (reference not available)

Source	min	mean	max
Validation	-37.5	1.088	30.25

Temporal — period Forecast init_time: 2025-06-27T00:00

Source	min	mean	max
P1 Validation	5.875	11.07	16.88
P2 Validation	-8.75	-1.738	3.625

Nulls — P1: 0/3437655 (none); P2: 0/3437655 (none)

$temperature_850hpa — null fraction$

temperature_850hpa — time series comparison

`temperature_925hpa`

Metadata

Field	Value
units	`degree_Celsius`
long_name	Temperature
short_name	t
standard_name	air_temperature
step_type	instant

Spatial — snapshot at init=2026-01-15T00:00, lead=24h (reference not available)

Source	min	mean	max
Validation	-39.25	3.711	34.75

Temporal — period Forecast init_time: 2025-06-27T00:00

Source	min	mean	max
P1 Validation	10.38	16.46	23.38
P2 Validation	-4.312	1.493	6.719

Nulls — P1: 0/3437655 (none); P2: 0/3437655 (none)

$temperature_925hpa — null fraction$

temperature_925hpa — time series comparison

`total_cloud_cover_atmosphere`

Metadata

Field	Value
units	`percent`
long_name	Total cloud cover
short_name	tcc
standard_name	cloud_area_fraction
step_type	instant

Spatial — snapshot at init=2026-01-15T00:00, lead=24h (reference at 2026-01-16T00:00)

Source	min	mean	max
Validation	0	67.71	100
Reference	0	61.3	100

Temporal — period Forecast init_time: 2025-06-27T00:00

Source	min	mean	max
P1 Validation	n/a	n/a	n/a
P1 Reference	0	60.3	100
P2 Validation	n/a	n/a	n/a
P2 Reference	0	85.52	100

Nulls — P1: 2596665/3437655 (599 unavailable (first: 2024-04-01T00:00:00, 2024-04-02T00:00:00, 2024-04-03T00:00:00 … last: 2025-11-18T00:00:00, 2025-11-19T00:00:00, 2025-11-20T00:00:00)); P2: 2596665/3437655 (599 unavailable (first: 2024-04-01T00:00:00, 2024-04-02T00:00:00, 2024-04-03T00:00:00 … last: 2025-11-18T00:00:00, 2025-11-19T00:00:00, 2025-11-20T00:00:00))

$total_cloud_cover_atmosphere — null fraction$

total_cloud_cover_atmosphere — spatial comparison

total_cloud_cover_atmosphere — time series comparison

`wind_gust_10m`

Metadata

Field	Value
units	`m s-1`
long_name	Maximum 10 metre wind gust since previous post-processing
short_name	10fg
standard_name	wind_speed_of_gust
step_type	max

Spatial — snapshot at init=2026-01-15T00:00, lead=24h (reference not available)

Source	min	mean	max
Validation	0.1348	8.638	50

Temporal — period Forecast init_time: 2025-06-27T00:00

Source	min	mean	max
P1 Validation	1.688	5.914	12.25
P2 Validation	4.188	16.7	28.75

Nulls — P1: 968184/3397212 (226 unavailable (first: 2024-04-01T00:00:00, 2024-04-02T00:00:00, 2024-04-03T00:00:00 … last: 2024-11-10T00:00:00, 2024-11-11T00:00:00, 2024-11-12T00:00:00)); P2: 968184/3397212 (226 unavailable (first: 2024-04-01T00:00:00, 2024-04-02T00:00:00, 2024-04-03T00:00:00 … last: 2024-11-10T00:00:00, 2024-11-11T00:00:00, 2024-11-12T00:00:00))

$wind_gust_10m — null fraction$

`wind_u_100m`

Metadata

Field	Value
units	`m s-1`
long_name	100 metre U wind component
short_name	100u
standard_name	eastward_wind
step_type	instant

Spatial — snapshot at init=2026-01-15T00:00, lead=24h (reference at 2026-01-16T00:00)

Source	min	mean	max
Validation	-36.5	0.4885	30.75
Reference	-50.5	0.3969	43.5

Temporal — period Forecast init_time: 2025-06-27T00:00

Source	min	mean	max
P1 Validation	-6.688	0.8112	9.875
P1 Reference	-5.688	-0.3288	5.125
P2 Validation	-1.594	10.07	18.5
P2 Reference	-2.812	9.155	20

Nulls — P1: 0/3437655 (none); P2: 0/3437655 (none)

$wind_u_100m — null fraction$

`wind_u_10m`

Metadata

Field	Value
units	`m s-1`
long_name	10 metre U wind component
short_name	10u
standard_name	eastward_wind
step_type	instant

Spatial — snapshot at init=2026-01-15T00:00, lead=24h (reference at 2026-01-16T00:00)

Source	min	mean	max
Validation	-29	0.236	25.25
Reference	-48.5	0.1875	43

Temporal — period Forecast init_time: 2025-06-27T00:00

Source	min	mean	max
P1 Validation	-4.062	0.5183	5.312
P1 Reference	-6.5	-0.2775	4.5
P2 Validation	-1.734	8.706	17.25
P2 Reference	-3.062	7.231	16.75

Nulls — P1: 0/3437655 (none); P2: 0/3437655 (none)

$wind_u_10m — null fraction$

`wind_v_100m`

Metadata

Field	Value
units	`m s-1`
long_name	100 metre V wind component
short_name	100v
standard_name	northward_wind
step_type	instant

Spatial — snapshot at init=2026-01-15T00:00, lead=24h (reference at 2026-01-16T00:00)

Source	min	mean	max
Validation	-28.75	-0.1865	31.25
Reference	-42.5	-0.1692	61.5

Temporal — period Forecast init_time: 2025-06-27T00:00

Source	min	mean	max
P1 Validation	-2.469	0.5739	6.938
P1 Reference	-7.438	-1.132	3.812
P2 Validation	-23	-3.082	14.12
P2 Reference	-27	-4.78	9.25

Nulls — P1: 0/3437655 (none); P2: 0/3437655 (none)

$wind_v_100m — null fraction$

`wind_v_10m`

Metadata

Field	Value
units	`m s-1`
long_name	10 metre V wind component
short_name	10v
standard_name	northward_wind
step_type	instant

Spatial — snapshot at init=2026-01-15T00:00, lead=24h (reference at 2026-01-16T00:00)

Source	min	mean	max
Validation	-24.25	-0.08725	24.25
Reference	-38	-0.1266	58.5

Temporal — period Forecast init_time: 2025-06-27T00:00

Source	min	mean	max
P1 Validation	-1.938	0.521	3.25
P1 Reference	-5.938	-1.125	3.156
P2 Validation	-18.5	-2.418	13
P2 Reference	-21	-3.803	8.5

Nulls — P1: 0/3437655 (none); P2: 0/3437655 (none)

$wind_v_10m — null fraction$