The La Niña weather pattern ended last month as Pacific Ocean temperatures rose and the El Niño Southern Oscillation cycle ...

The easy answer is a deep southward dip in the polar ... the vortex isn’t the only thing that influences the jet stream.

He dubbed this pattern the Southern Oscillation, a phenomenon we know today as the groundwork upon which El Niño and La Niña develop across ... a Canadian winter without hearing about the polar vortex ...