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  • Luke Boxall

Spot on forecast from 14 days out!

Unless you're a client of Met-Set, you would probably strongly disagree with this statement for the very strong wind event we have widely across the Northern half of Europe taking place around Thursday 11th March.


After all, the usual method of predicting weather is to take the ENS mean of the forecast which 14 days ago wanted 20GW of Germany Wind generation with temperatures around 1.5degC below normal - how is this a spot on forecast?!



When having discussions of computer models having skill in the medium range beyond the first 5 days - the variable that is used to describe this skill is the 500hPa Geopotential Height - as this is the variable that describes the over-riding pattern across Europe which has the most skill - below shows the CRPS score for 3 different variables 500hPa Geopot/850hPa temp and finally the surface parameter of 2m Temperature.



It can often be advantageous to use this knowledge to see what patterns are most likely over Europe in the medium-range, and then from that, infer what the surface parameters ought to be to see if it agrees - or disagrees - adding extra value out of the medium range forecast.



What about this current strong wind event - how did the pattern tool handle that?


Below shows the ECMWF 0z run every day between 26th February and 8th March and you can clearly see the clear consistent signal for WZ to occur on Thurs 11th March



Knowing that the pattern is most likely to be WZ (Westerly Cyclonic) - you can then use the Met-Set tool to see what the most likely German Wind generation is likely to be - below shows the forecast for German Wind Generation anomaly (difference from Normal in GWs) from each of the 0z ECMWF ENS runs between 26th February and 8th March and how that compares with the Pattern normal - we can see that with time the forecast merges with the pattern outturn




If that's not useful enough, the great advantage of using a pattern-based system is you get a European-wide view on out-turn not just the risk to Germany wind but also what that means to the wind elsewhere.


This time the graph compares the pattern outturn in the WZ pattern for UK Wind generation against the forecasts – again we can see that with time the forecast merges with the pattern outturn




Finally, an example for a country where the wind ought to be lower during a WZ pattern but models were incorrect with that too - below shows Spain wind generation




Wait, there's more, the other great advantage of using a pattern-based system is not only do you get a European-wide view but it also can be used across all different kind of variables.


This time the graph compares the pattern outturn in the WZ pattern for Germany Temperature against the forecasts – again we can see that with time the forecast merges with the pattern outturn





I suspect the vast majority of people reading this will already be clients that are familiar and like the analysis/work being produced but if by some chance this reaches someone not already a client and wants to have a look from themselves with a trial - please contact us at:


enquiries@met-set.com

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