where to find instruction or explanations

Greetings from belgium

I have interest in long term weather forecasting mainly in view of travel
projects and paragliding.

In view of this I would like to be able to better understand what the plots
generated by following site :

http://85.214.49.20/wz/metsonst.html

mean for the weather to be expected at the time and area of the plot.

I studied economics so I have little scientific background - still I did
some gliding and read somewhat about meteorology, many many years ago.

Could somebody direct me to a website where I can find some understandable
(and if possible compact) instruction about this.

As my mother tongue is dutch (flemish actually), it would be great if the
instruction could be in that language.

Still I speak and understand engllish, french and german also.

Thanks on forehand for any hint.






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