Omega Blocking pattern

An ongoing weather pattern named Omega Blocking is on stage in Europe.

It happens when there are (at least) 2 cyclonic areas (B) on the flanks of an anticyclone (A) that is "stretched" to shape similar to the omega letter (see the map. The shape is more "defined" than other Omega blocking involving North America).

https://i.redd.it/416doe4ub3nb1.gif

This is associated to temperatures higher than the average in the A area and massive and long lasting rainfalls on the B zone in the eastern flank.

Indeed NW Greece has experience bad rainstorms. While the B zone is moving to the libic sea the rain is going to hit SE Italy.

In northern Italy we 5 degrees above the Sept normal and no wind at all (same thing is expected in central/north Europe).

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https://i.redd.it/37o8umsvb3nb1.gif

I read on some newspapers that this is caused by high altitude winds forced to move in only one direction NW-SE so causing rain on the flank and heat in the center

Any easy (for dummies) explanation on why this happens and why (sorry for being dumb) the A area last and is not washed out/diluted by the nearby B zones (low pressure would imply that it draw winds from A zones)?