Prior to the IFS cycle 47r1, the EFI for both CAPE and CAPE-shear has used instantaneous CAPE (ShortName=cape; parameter ID=59) and CAPE-shear (ShortName=capes; parameter ID=228044) in 6-hour steps from which 24-hour maximum values have been computed. For example for T+24-48h EFI forecast, four CAPE values at T+30h, T+36h, T+42h and T+48h have been used to compute the maximum for this forecast period. With the IFS cycle 45r1 two new model output parameters, maximum CAPE in the last 6 hours (ShortName=mxcape6; parameter ID=228035) and maximum CAPE-shear in the last 6 hours (ShortName=mxcapes6; parameter ID=228036), have been introduced (see details here). In the IFS cycle 47r1 mxcape6 and mxcapes6 are replacing cape and capes respectively. This change is aiming for a better sampling in the computation of 24-hour maximum values necessary for the EFI. The impacts of this change are described in detail below.
As a result of taking instantaneous cape and capes at discrete steps the EFI can exhibit a stripy structure in a case of fast moving squall fronts as in the example in Fig ... . Apparently this is an issue because the cold front is not jumping rather it is moving continuously from west to east. Replacing cape and capes with mxcape6 and mxcapes6 removes the stripy behaviour and provides a smoother forecast field due to better sampling.
The EFI for CAPE-shear as well as CAPE-shear high-resolution forecast in a case of a fast moving cold front. Stripy fields of instantaneous CAPE -shear and the EFI is due to taking instantaneous CAPE-shear values at discrete time steps. The EFI forecast looks smoother when using the smoother fields of maximum CAPE-shear in 6-hour periods. The sequence of Air mass RGB imagery shows snapshots of the cold front approaching the south-western parts of the Iberian Peninsular.