Last fall I
predicted a cold and snowy winter for western Canada
and then promptly left for Palm
Springs Edmonton , Alberta Edmonton has had
no real winter, and most of Canada
It was, and
still is a La Nina winter. It should be cold and snowy and has been anything
but. That cold air that builds up over the arctic has to go somewhere. Like a
dam bursting it often floods southward over Siberia or northwestern Canada
A recent
study by a US/China team of researchers determined that it was the result of
diminishing ice coverage in the arctic. Open water in the arctic during fall
and early winter means that the surface temperature from the Arctic to the
north Atlantic differs much less than normal – a weak thermal gradient. That
results in a weak jet stream across the north Atlantic .
A strong
jet stream across the north Atlantic is
believed to help keep the arctic air from flooding southward into eastern
Europe except briefly and occasionally. This winter they have been devastated
with dreadfully cold and snowy conditions. There was even snow in the Sahara last month.
I suspect
that the flooding of arctic air over Europe actually reduces the pressure to
flood southward over Siberia or western Canada Canada
As it is
now late winter and the Arctic is freezing
again, we may be seeing a strengthening of the north Atlantic jet and a return
to normal La Nina conditions. That would mean a cold and snowy end to winter
and probably a late spring. However, La Nina is now expected to fade to neutral
conditions by early spring and so we can hope for normal weather patterns to
return for the first time in a few years.
No comments:
Post a Comment