"Adam Lea" wrote in message
...
Does anyone have any idea of why the jet stream is so far south at the
moment? I've just looked at the GFS forecast for this week and it has the
polar jet south of the UK later in the week, and it doesn't seem to be in
any hurry to move away from that latitude.

What atmospheric processes are capable of shifting the jet stream further
north, closer to where it should be for the time of year?

FWIIW, I do not think it is a direct consequence of global warming, as I
would have expected GW to move the Jet Stream northwards.

I blame the extent of Arctic sea ice which was almost back to normal during
April:
http://nsidc.org/data/seaice_index/i...timeseries.png.

It is just a matter of waiting for the JS to flip back north and then the
Barbaque Summer can begin :-)

OTOH, flpping the Jet Stream might lead to a European Monsoon.

Cheers, Alastair.