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In the end the following factors will increase the prognosed forecasted lightning density:

• Higher CAPE
• More condensate in the convective updraught (between levels at 0ºC and -25ºC)
  • More snow in the said convective updraught
  • More graupel in the said convective updraught
• A higher convective cloud base (if less than 1.8km)

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• are displayed as units per 100km² (i.e. per 10km x 10km square, or ~0.1^ox0.1^o) surrounding the relevant grid point.  So HRES does not indicate lightning strikes precisely at a given location. Recall also that HRES gridboxes grid boxes measure about 9km by 9km, so greater detail than in raw model output is not possible.  Note also that strikes more than 10km away may be visible (or audible) to an observer.
• verify better when considered over larger areas and/or over longer time scales.
• often show peak activity about an hour earlier than observed.
• often show activity decaying away too early in the afternoon while in reality thunderstorms continue through the afternoon and often linger well into the night.
• often show lightning activity to be too intense, particularly during periods of higher activity.
• when considered over several years, tend to underestimate activity when compared with a 10 year climatology of satellite data, particularly over central Africa but also over parts of eastern Europe and central Asia.  Conversely, it is possible there is too much activity forecast over parts of the tropical Pacific.
• can exhibit systematic errors in the European area during the autumn in particular; at times there will be much more activity over the Mediterranean (sea area) than predicted (this may relate to the assumptions about graupel distributions over land and sea).

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