In summer 2015 ECMWF introduced, in test mode, two new EFI parameters for forecasting severe convection - the EFI for CAPE and the EFI for CAPESHEAR - that are described below. The test period is now over: , and accordingly the parameters are now included in the ECMWF real-time catalogue (see here) , and accordingly are available in dissemination. In the catalogue the EFIs for CAPE and CAPESHEAR have the short names of "capeiCAPEI" and "capesiCAPESI" respectively. Charts based on the parameters continue to be available on the ECMWF web-site (here).
...
While a global NWP model cannot be expected to forecast individual convective cells, such a model can tell the user whether the broadscale environment is favourable for development of deep moist convection (DMC). Based on this premise, and following user requests and extensive testing, two the new EFI parameters have been were added to assist with the forecasting of severe convection: the EFI for CAPE and the EFI for CAPESHEAR (=CSP, for "CAPESHEAR Parameter").
...
- The EFI fields for both CAPE and CSP show where severe convection is likely if it initiates. This means that in general high EFI values include also areas where DMC does not develop, for example because a capping inversion, as denoted by convective inhibition (CIN), is too strong. To help determine whether DMC will initiate or not one can employ also the probability forecast for precipitation (for example), in conjunction with the EFI EFIs for CAPE and CSP (Figure 1).
- The EFI shows the extremity of a given parameter compared to the model climate. Hence high values of the EFI may appear in areas where no severe convection develops because even the more extreme values of the convective parameters in the model climate are too low. For example this can happen over the continents in winter. Conversely a large CSP EFI would be particularly concerning if seen in an area and at a time where organised DMC was relatively common.
...
Figure 1. EFI forecasts for A) CSP; B) CAPE; C) CSP where probability of precipitation above 1mm/24h is greater than 5%; D) CAPE where probability of precipitation above 1mm/24h is greater than 5%. The EFI signal disappears over a large part of Germany except the northern areas after filtering out EFI values where probability of precipitation above 1 mm/24h is less than 5%. Severe convection developed only over the northern parts of Germany, whilst oevr over the rest of the country it stayed dry and sunny.