Downscaling of sub-seasonal forecasts (using ECMWF's ecPoint tool)

SUB-SEA forecast from day 15 to 30 over Italy. The sub-seasonal ecPoint (Sub-SEA) are post-processed products delivering (global) probabilistic forecasts at point-scale (instead of at grid-box scale) of 24-hour precipitation, and minimum, maximum and mean 2m temperatures in 24h periods, for weeks three and four (days 16-30) of ECMWF's sub-seasonal forecasts that currently run twice per week. They are real-time products based on the ECMWF ensemble (ENS) forecast system, which has 51 ensemble members run at ≃0.35° horizontal resolution (≃36km), with the final outputs for ecPoint precipitation and temperature provided in percentiles for each grid box. EcPoint is a new and innovative statistical post-processing technique developed by ECMWF that is used to downscale relatively low-resolution (global) numerical model output to point scale. ecPoint products explicitly incorporate the expected sub-grib variability, as well as bias correction for gridbox means (which both vary according to the grid-box weather type).

SUB-SEA ecPoint forecast from day 16 to 30 over Italy (percentiles and bias-corrected ensemble members):

1. Maximum temperature at 2 metres in 24 hours (K)

2. Minimum temperature at 2 metres in 24 hours (K)

3. Total precipitation in 24 hours (kg m**-2)

4. Mean temperature at 2 meters in 24h (k)