ECMWF offers three file-naming convention templates for real-time product delivery via the ECMWF Production Data Store (ECPDS). These templates can be selected using the Product Requirements Editor (PRED) if you have access, otherwise requests of template change can be made through the ECMWF Support Portal.

Template IFS (class=od) AIFS (class=ai) IFS-COMPO (CAMS) (class=mc) Status / Lifecycle
LEGACY Supported Not supported Not supported Phasing out Q1 2027 (with IFS Cycle 50r2)
ECMWF

Supported (Default)

 Supported (Default) Supported (Default) Active
WMO

Supported

Supported

Supported

 Active

1. LEGACY

Feed Stream

BasedDate
(MMDDHHmm)

ValidDate
(MMDDHHmm)

 Experiment
A1 D 07 25 00 00 08 08 18 00 1
A1D07250000080818001
  • Feed: The feed name, as defined in the PREd
  • Stream: The stream indicator (see table below)
  • Based Date: The month, day, hour and minute on which the products are based (in MMDDHHmm format)
  • Valid Date: The month, day, hour and minute at which the products are valid (in MMDDHHmm format)
    • MMDDHHmm is set to "MM______" for seasonal forecast products, where MM indicates the valid month
    • mm is set to "01" for high resolution forecast (type=fc, step=0)
  • Experiment: The version number (as EXPVER keyword in MARS, operational files use 1). 

1.1. Stream indicator

S

Stream,
Type

Description

Forecast Range

Runs
Frequency
A stream=oper,
type=wp		 IFS Medium-range Control Forecast - Weather Parameter 15-day 00z/12z
daily
B stream=enfo,
type=wp		 IFS Medium-range Ensemble Forecast - Weather Parameter 15-day 00z/12z
daily
C stream=oper, 
type=tf		 IFS Medium-range Control Forecast - Tropical Cyclone trajectory 15-day 00z/06z/12z/18z
daily
D stream=oper IFS Medium-range Control Forecast - Atmospheric model
IFS High Resolution Data Assimilation 
 15-day 00z/06z/12z/18z
daily
E stream=enfo IFS Medium-range Ensemble Forecast - Atmospheric model 15-day 00z/06z/12z/18z
daily
F stream=eefo IFS Sub-seasonal Forecast - Atmospheric model 46-day 00z
daily
G stream=waef  IFS Medium-range Ensemble Forecast - Wave model 15-day 00z/06z/12z/18z
daily
H stream=eefh/eehs IFS Sub-seasonal Reforecast - Atmospheric model 46-day 00z
every other day (1/3/5...)
I

stream=enfh/efhs

IFS Medium-range Reforecast - Atmospheric model

15-day

00z
every four days (1/5/9...)
J stream=enwh/wehs IFS Medium-range Reforecast - Wave model 15-day 00z
every four days (1/5/9...)
L stream=mmsm/mmsf/mmsa IFS Seasonal Forecast - Atmospheric model 7-months 00z
monthly (5th of a month)
M stream=oper,
type=fc		 IFS Medium-range Control Forecast - Thermofeel 15-day 00z/06z/12z/18z
daily
N stream=wasf IFS Seasonal Forecast - Wave model 7-months 00z 
monthly
O stream=enfo,
type=pf/cf 		 IFS Medium-range Control Forecast - Thermofeel 15-day 00z/06z/12z/18z
daily
P stream=wave IFS Medium-range Control Forecast - Wave model
IFS High Resolution Data Assimilation 
 15-day 00z/12z
daily
Q stream=scwv IFS Medium-range Control Forecast - Wave model 15-day 06z/18z
daily
T stream=enfo,
type=tf		 IFS Medium-range Ensemble Forecast - Tropical Cyclone trajectory products 15-day 00z/06z/12z/18z
daily
U stream=waef,
type=em/efi/sot/ep		 IFS Medium-range Ensemble Forecast - Wave model - Post-processed products 15-day  00z/06z/12z/18z
daily
V stream=weef IFS Sub-seasonal Forecast - Wave model 46-day

00z
daily
W stream=waef  IFS Medium-range Control Forecast - Wave model - Probabilistic 15-day 00z/06z/12z/18z
daily
Y stream=enfo,
type=em/efi/sot/ep		 IFS Medium-range Ensemble Forecast - Wave model -  Post-processed 15-day 00z/06z/12z/18z
daily 
Z stream=weeh/wees IFS Sub-seasonal Reforecast - Wave model  46-day 00z
daily  
(*) 2 metre relative humidity (2r), Apparent temperature (aptmp), Globe temperature (gt), Heat index (heatx), Humidex (hmdx), Mean radiant temperature (mrt), Normal effective temperature (nefft), Universal thermal climate index (utci), Wet-bulb globe temperature (wbgt), Wet-bulb temperature (wbt), Wind chill factor (wcf)
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2. ECMWF

2.1. Medium-Range

Destination Feed ModelName Class Stream Type BasedDate
(YearMonthDayTHourMinuteSecondsZ)		 ValidDate
(YearMonthDayTHourMinuteSecondsZ)		 Step
(Hourh)		 Experiment
(Optional)
abc a1 aifs-ens ai enfo pf  20250725T000000Z  20250808T180000Z  354  
abc_a1_aifs-ens_ai_enfo_pf_20250725T000000Z_20250808T180000Z_354h
  • Destination: The destination name used in ECPDS. The file-naming convention will always use the name of the primary destination where the data are installed, even if you receive the files via an alias destination.
  • Feed: The feed name, as defined in the PREd
  • ModelName: The model identifier
  • Class: The class of forecast data
  • Stream: The stream name
  • Type: The type of forecast
  • BasedDate: The base date and time of the product, in the format YYYYMMDDTHHMMSSZ (ISO 8601 format) (This marks when the forecast was initiated)
  • ValidDate: The date and time for which the product is valid, in the format YYYYMMDDTHHMMSSZ (ISO 8601 format) (This marks the time the forecast is intended to represent)
  • Step: The forecast step in hours
  • Experiment: The experiment version number (as EXPVER keyword in MARS, operational files use 1) (Not shown when operational)

2.2. Sub-seasonal

Destination Feed ModelName Class Stream Type BasedDate
(YearMonthDayTHourMinuteSecondsZ)		 ValidDate
(YearMonthDay)		 Step
(dDay)		 Experiment
(Optional)
abc a1 ifs-subs od eefo cf  20260419T000000Z 20260604  47  
abc_a1_ifs-subs_od_eefo_cf_20260419T000000Z_20260604_d47
  • ValidDate: The date which the product is valid, in the format YYYYMMDD (This marks the time the forecast is intended to represent)
  • Step: The forecast step in days

2.3. Seasonal

Destination Feed ModelName Class Stream Type BasedDate
(YearMonthDayTHourMinuteSecondsZ)		 ValidDate
(YearMonth)		 Step
(MMonth)		 Experiment
(Optional)
abc a1 ifs-seas od mmsf fc  20260401T000000Z 202610  07  

abc_a1_ifs-seas_od_mmsf_fc_20260401T000000Z_202610_M07
  • ValidDate: The date which the product is valid, in the format YYYYMM (This marks the time the forecast is intended to represent)
  • Step: The forecast step in months


3. WMO

PFlag ProductIdentifier
(locationIndicator,modelName,destination+
feed+class+stream+type +expver)		 OFlag Originator ProductionDate
(YearMonthDayTHourMinuteSeconds)		 FreeFormat
(ValidDate_Step_FileFormat)
(YearMonthDayTHourMinuteSecondsZ_Step_FileFormat)		 Extension
W xx-ecmwf-reading,aifs+single,egs+e5+ai+oper+fc+0001 C ECMF 20250725T000000 20250808T180000Z_354h_grib bin

W_xx-ecmwf-reading,aifs+single,abc+a1+ai+enfo+pf+0001_C_ECMF_20250725T000000_20250808T180000Z_354h_grib.bin
  • PFlag: Indicating how to decode the product identifier field
  • ProductIdentifier: Comma-separated values indicating the location, model name, and product metadatalocationIndicator
    • Location: The WMO location indicator of the production centre
    • ModelName: The model identifier
    • Destination: The destination name used in ECPDS. The file-naming convention will always use the name of the primary destination where the data are installed, even if you receive the files via an alias destination.
    • Feed: The feed name, as defined in the PREd
    • Class: The class of forecast data
    • Stream: The stream name
    • Type: The type of forecast
    • Expver: The experiment version number (as EXPVER keyword in MARS, operational files use 1) (Not shown when operational)
  • OFlag: Indicating how to decode the originator field
  • Originator: WMO originator code
  • ProductionDate: Based date and time of the product, in the format YYYYMMDDTHHMMSS (This marks when the forecast was initiated)
  • FreeFormat: A free-format field containing valid date, step and file format
    • ValidDate: The date and time for which the product is valid, in the format YYYYMMDDTHHMMSSZ (ISO 8601 format) (This marks the time the forecast is intended to represent)
    • Step: The forecast step in hours or days
    • FileFormat: The format of the data file
  • Extension: The file extension


File Format

About half of ECMWF products are encoded in WMO FM-92 GRIB edition 1, and the other half in GRIB edition 2, unless otherwise specified in our Catalogue of Real-time products. For more details, see the Migration to GRIB edition 2 Information page.

However, some product subsets use different encoding formats:

  • IFS model level parameters are encoded in WMO FM-92 GRIB edition 2.

  • AIFS products are encoded in WMO FM-92 GRIB edition 2.

  • Time Series of Weather Parameters and Tropical Cyclone tracks types are encoded in WMO FM-94 BUFR format.


Possible ModelName, Class and Streams for ECMWF and WMO templates

Full Name ModelName Class Stream Type

IFS High Resolution Data Assimilation 

ifs-da

od

oper/wave

an

IFS Medium-range Ensemble Forecast 

 ifs-ens od enfo/waef cm/cr/efi/efic/em/ep/es/gbf/gwt/pf/pfc/pproc/sot/tf/wp

IFS Medium-range Control Forecast

 ifs-ens-cf od oper/wave fc/gbf/gwt/pproc/ssd/tf/wp

IFS Medium-range Reforecast

 ifs-ens-refc od enfh cf/pf
IFS Sub-seasonal Forecast  ifs-subs od eefo/weef cf/efi/ep/fcmean/pb/pd/pf/sot/taem
IFS Sub-seasonal Reforecast  ifs-subs-refc od eefh cf/fcmean/pf

IFS Seasonal Forecast 

 ifs-seas od mmsa/mmsf/msmm/wasf em/fc/fcmean

AIFS Single Forecast 

 aifs-single ai oper/wave fc/tf

AIFS Ensemble Forecast 

 aifs-ens ai enfo/waef cf/em/ep/es/pf/tf

IFS Atmospheric Composition Forecast

 ifs-compo mc oper fc

IFS Atmospheric Composition Data Assimilation

 ifs-compo-da mc oper an
  • Type pproc has been introduced for derived products, including thermofeel parameters.