ECMWF provides data from different IFS models, with different frequencies according to when the IFS models are run, and with different temporal resolutions in the output data. Output data is in the form of a) instantaneous values, b) averages over a period, c) totals over a period, d) maxima or minima over a period. Commonly output shows absolute values, but sometimes anomalies relative to re-forecast data are provided.
Medium Range forecasts, based on 00UTC and 12UTC data time are available for the following forecast times:
- HRES, HRES-WAM and HRES-SAW: analysis and forecasts - hourly up to T+144, 3-hourly from T+150 to T+240(day10).
- ENS, ENS-WAM based on 00UTC and 12UTC: 3 hourly up to T+144, 6-hourly from T+150 to T+360(day15).
Additional Medium Range forecasts, based on 06UTC and 18UTC data times, available to Members of the Boundary Conditions (BC) optional programme (members using ECMWF IFS model forecast values as boundary conditions for their own local areas models) are available for the following forecast times:
- HRES: analysis and forecast - hourly up to T+144(day6).
Extended Range forecasts, Mondays and Thursdays based on 00UTC data time are available for the following forecast times:
- ENS-extended, ENS-WAM-extended: 6 hourly from T+366 to T+1104 day(46).
- ENS-extended, ENS-WAM-extended means and anomalies (output for corresponding forecast weeks) on:
- Mondays: T+0 to T+168(day7), T+168 to T+336(day14), T+336 to T+504(day21), T+504 to T+672(day28).
- Thursdays: T+96 to T+264 (day11), T+264 to 432(day18), T+432 to T+600(day25), T+600 to T+768(day32).
Seasonal forecasts are made available on the 8th of each month based on 00UTC data time on 1st of each month in the form:
- Monthly means and anomalies.
See available datasets for more detail of the resolution of the data and the parameters available.
Note: Precipitation forecasts are provided as values accumulated from the start of the forecast integration. The range of the daily variation of the forecast 2m temperature and wind gust is best estimated by retrieving the forecast maximum and minimum values. The combination of accumulated and instantaneous forecast information can occasionally lead to inconsistencies as in both cases the valid time is defined as the time at the end of the period (e.g. during the passage of a cold front when significant precipitation amounts might be accumulated by theIFS models over the whole time interval though instantaneous cloud-free conditions will be shown at the end of the interval).