Extreme Forecast Indices (EFI) and Shift of Tails (SOT) now available

In general, weather forecasts differ regarding their quality. This variability can be displayed by the usage of so-called model ensembles. If several forecasts exhibit similar weather conditions, conclusions concerning unusual and extreme conditions can be drawn. This additional value is now offered in the Meteomatics API in the form of two indices:

  • EFI - extreme forecast indices, say how likely an unusual condition is to occur

  • SOT - shift of tails of the cumulative model ensemble distribution, says how extreme these unusual condition would be, should they occur.

EFI and SOT indices are available for a whole set of weather parameters and several time periods (see documentation of extreme weather):

  • wind speed
  • temperature
  • precipitation
  • snow fall
  • significant wave height
  • water vapor flux
  • CAPE


The EFI for accumulated precipitation over 3 days from August 2 until August 3, 2020. During this period heavy rainfall events occurred in central Europe.


The EFI for wind speed at 10 m over 3 days from August 2 until August 3, 2020. During this period tropical storm Isaias moved along the US East Coast.


The EFI for significant wave height highlights regions that are likely to deviate from a smooth median climate.