Note: HRES and Ensemble Control Forecast are scientifically, structurally and computationally identical.  With effect from Cy49r1, Ensemble Control Forecast output is equivalent to HRES output where shown in the diagrams.  

ECMWF Web Charts

Open Access Charts

ECMWF Web Charts (Open Access) give easy access to forecast output from ECMWF Integrated Forecast System (IFS) and Artificial Intelligence Forecast System (AIFS).

A range of ECMWF output is available in chart form and can be found through the Open Access Charts Catalogue of the ECMWF website.  

Most charts show a pre-formed combination of forecast products (e.g. MSLP and precipitation, relative humidity and wind at 850hPa, etc, but some have the flexibility to change parameter values (e.g. change to relative humidity and winds at 700hPa).  

Charts are generally at 24hr intervals, but some are at 12hr or 6hr intervals, and the user can select the interval required on a few.  Most chart options allow the user to select from a list of pre-defined geographical areas.

Forecast charts on open access charts pages fall into three forecast ranges: Medium Range (15 day forecast period), Sub-seasonal Range (16-46 day forecast period), and Seasonal Range (7 to 13 months forecast period).

Note: The icon of four small squares at the top of the selection list is to show side-by-side display of many forecasts.  These may be for the same verifying time from recent forecast runs, or for a sequence of results from the selected forecast run.  This allows ready comparison of forecasts.

Medium Range (15 day forecast period)

IFS Medium Range Ensemble Control output

Ensemble Control Forecast output gives "deterministic" snapshots of the forecast evolution for various combinations of parameters.  It is important not to be beguiled into treating Ensemble Control Forecast charts as definitive, despite the apparent detail.  The Ensemble Control Forecast should only be considered as one member of the medium range ensemble.

There is a wide range of forecast charts which show:

• surface and upper air data (e.g. pressure, temperature, wind). (Example chart).
• derived atmospheric parameters (e.g. CAPE, shear, vorticity). (Example chart).
• derived totals and types of precipitation (e.g. broad scale, convective, rain, snow). (Example chart).
• sea waves and swell (e.g. period and height of mean and significant waves and directions). (Example chart).
• derived parameters (e.g. cloud cover, sunshine). (Example chart). 
• simulated imagery (e.g. visible, infra-red, water vapour). (Example chart).

Simulated infra-red and water-vapour imagery charts are derived from the structure of the IFS model atmosphere.  They provide a useful comparison with observed satellite imagery, and analysed and forecast upper air flow patterns.  They may be particularly useful for seeing whether the model is replicating small scale features in the flow. (Example Vis chart, Example IR chart, Example WV chart).

Model diagnostic output is shown to allow the user to assess the impact of the latest observations or the modelled state of the underlying surface of the earth.
Charts available:

• Analysis increment charts - to allow identification of sources of potential problems in the forecast evolution.  (Example chart).
• Surface parameter charts - to indicate the surface conditions used by ensemble control runs that govern radiation and other exchanges with the atmosphere.  These allow the user to assess any shortcomings (e.g. insufficient snow cover, soil moisture, leaf area index etc). (Example chart).

IFS Medium Range Ensemble output

IFS Medium range ensemble output gives information from the ensemble forecast evolution for various combinations of parameters.  In general ensemble forecasts show individual and combined parameters presented in a probabilistic or multi-valued format.  A few charts show forecast parameters of individual ensemble members to show the variability.

There is a wide range of forecast charts which show:

• Mean and Spread charts (including clickable multi-parameter charts) of surface and upper air data (e.g. pressure, temperature, wind). (Example chart).
• Mean and Spread charts - to place the uncertainty measured by the standard deviation of the members of the latest ensemble into the context of recent uncertainty in the ensemble forecasts.  (Example chart).
• Probability charts - to show probabilities of events exceeding a given threshold (e.g. rainfall > 5mm/day).  (Example chart).
• Extreme Forecast Index charts (including clickable multi-parameter charts) - to highlight areas where forecast values depart significantly from M-climate. (Example chart).
• Plumes, Meteograms, EFI-CDF, Vertical Profiles - to give probabilistic interpretation of the ensemble for specific locations with optional M-climate data to emphasize departure from the re-forecast climatology.   
• Cluster charts - to distil ensemble member output into groups exhibiting similar large-scale patterns enabling assessment of most likely results (i.e. possible 'weather scenarios').  (Example chart).
• Tropical cyclone activity charts (including genesis) - to indicate tropical cyclone threats worldwide. (Example chart).
• Postage stamp charts - to show the output of all ensemble members for a few parameters at several forecast lead-times. (Example chart).

Mouse click over any location on the "clickable"  ensemble charts will produce probability information in diagrammatic form on several parameters at that location.

Parameter diagrams available:

• • 10 day Meteogram.
  • 15 day meteogram.
  • 15 day meteogram with M-climate.
  • 15 day wavegram.
  • Plume.
  • EFI-CDF.
  • Vertical profile.

AIFS Single output

AIFS Single output gives "deterministic" snapshots of the forecast evolution for various combinations of parameters.  It is important not to be beguiled into treating Ensemble Control Forecast charts as definitive, despite the apparent detail.  AIFS Single should only be considered as another solution to be compared with output from AIFS Ensemble.  AIFS Ensemble Control forecast is part of the AIFS Ensemble and is separate from AIFS Single.  

There is a wide range of forecast charts which show:

• surface and upper air data (e.g. pressure, temperature, wind). (Example chart).
• derived totals and types of precipitation (e.g. broad scale, convective, rain, snow). (Example chart).
• sea waves and swell (e.g. period and height of mean and significant waves and directions). (Example chart).
• derived parameters (e.g. cloud cover).  (Example chart).

AIFS Ensemble Control output

• surface and upper air data (e.g. pressure, temperature, wind). (Example chart).
• derived totals and types of precipitation (e.g. rain, snow). (Example chart).
• sea waves and swell (e.g. period and height of mean and significant waves and directions). (Example chart).
• derived parameters (e.g. cloud cover). (Example chart).

AIFS Medium Range Ensemble output

AIFS Medium Range Ensemble output gives information from the ensemble forecast evolution for various combinations of parameters.  In general ensemble forecasts show individual and combined parameters presented in a probabilistic format. 

• Mean and Spread charts of surface and upper air data (e.g. pressure, temperature, wind). (Example chart).
• Probability charts - to show probabilities of events exceeding a given threshold (e.g. rainfall > 5mm/day).  (Example chart).
• Meteograms. (Example diagram).

Sub-seasonal Range (16-46 day forecast period)

IFS Sub-seasonal Range Ensemble

Sub-seasonal range ensemble products are derived from an extension of the normal 15 day ensemble daily.   They act as a bridge in time between medium range ensemble forecasts and seasonal forecasts.  The charts available cover week-long periods (i.e. 7-day periods after the data time of the forecast run, going up to date46).   The sub-seasonal range ensemble consists of 100 members plus one control member.
Charts available:

• Weekly mean anomaly charts - to highlight areas where mean forecast values depart significantly from the SUBS-M-climate for each location within the chart area. (Example chart).
• Quantile-based weekly guidance maps. (Example chart).
• Weekly probability anomaly charts - to highlight the probability of being above the SUBS-M-climate mean for each location within the chart area. (Example chart).
• Weekly probability charts - to show the probability the weekly mean anomalies will be in lower and upper quantiles of the SUBS-M-climate for each location within the chart area. (Example chart).
• Weekly averages of the monthly forecast ensemble for several variables on a single chart. (Example chart).
• Tropical cyclone probability charts (including genesis) - to indicate tropical cyclone threat and intensity worldwide and compare with tropical cyclone frequency and intensity in the SUBS-M-climate. (Example chart).
• Time-longitude (Hovmoeller) diagram of the observed and forecast ensemble mean anomaly of 500hPa or 1000hPa geopotential (in dam) in the extra-tropics - to show persistence and progression of disturbances and potential interaction between upper and lower features. (Example diagram).
• Madden-Julian Oscillation (MJO) index metrics and Wheeler-Hendon MJO diagram - to show recent and forecast evolution and uncertainty of MJO features. (Example MJO index metrics Hovmoeller diagram, example Wheeler-Hendon MJO diagram).
• Sub-seasonal meteogram (Example diagram).
• EFI for sub-seasonal range. (Example chart).
• Weather regimes probabilities. (Example chart).
• Mean zonal wind anomaly 10hPa. (Example chart).
• Two dimentional PDFs of flow patterns over North Atlantic and Europe. (Example chart).
• Forecast anomalies evaluation. (Example chart).

Seasonal Range (7 to 13 months forecast period)

Seasonal ensemble

Seasonal forecast charts are derived from an ensemble (separate from the sub-seasonal range ensemble) run on the 1st of each month out to 7 months, extended to 13 months each quarter (i.e. every 3 months).   The charts available mostly cover 3-month periods, with the first valid period typically beginning 1 month after data time.
Charts available:

• Monthly mean probability of anomaly charts - to highlight areas where ensemble forecast values depart significantly from the S-M-climate for each location within the chart area. (Example chart).
• Climagrams - box and whisker diagrams comparing the distributions of parameter averages within pre-defined regions:
  • as forecast by the seasonal ensemble,
  • as represented in the S-M-climate re-forecasts,
  • and as represented in re-analyses.
    (Example climagram).
• Tropical storm probabilities and anomalies against S-M-climate. (Example chart).
• Niño plumes - show the range of seasonal forecasts of sea-surface temperature over pre-defined regions of equatorial Pacific. (Example plume).

Verification Metrics for Sub-seasonal and Seasonal forecasts

Provided alongside the forecasts are measures of the skill (Relative Operating Characteristics (ROC) and reliability that were "achieved" within the respective re-forecast periods.  Forecasters should always consider forecasts at these longer lead times in the context of these verification scores.  Using verification metrics to aid assessment of the predictability.  (Example ROC diagram, example reliability diagram).

(FUG associated with Cy50r1)