Arctic Sea Ice or Siberian Snow best for winter forecasts?
At the AGU went looking for leading sea ice extent researcher Jen Francis at Rutgers, who has become known for arguing that the extent of sea ice/Arctic Amplification alters the jetstream (making it "wavier") and leads to extreme weather in places like the Northeast and northern Europe.
Or, as she told the NYTimes this spring, during a heat wave:
“This means that whatever weather you have today — be it wet, hot, dry or snowy — is more likely to last longer than it used to,” said Dr. Francis, who published a major paper on her theory a few weeks ago.
“If conditions hang around long enough, the chances increase for an extreme heat wave, drought or cold spell to occur,” she said, but the weather can change rapidly once the kink in the jet stream moves along.
Then along comes Superstorm Sandy, and she thinks that's related too:
Blocking happens naturally, of course, but it’s very possible that this block may have been boosted in intensity and/or duration by the record-breaking ice loss this summer. Late-season hurricanes are not unheard of either, but Sandy just happened to come along during this anomalous jet-stream pattern, as well as during an autumn with record-breaking warm sea-surface temperatures off the US east coast.
As the story by Justin Gillis mentions, not everyone in the field agrees. While visiting with Francis, and trying to understand what she might know about warming on the West Coast, I happened to see her being asked questions by another highly-respected winter forecaster Judah Cohen.
These two agree that the warming of the Arctic impacts weather in the Northeast and Europe, but Francis is more focused on Arctic Amplification, Rossby waves, and sea ice extent, and Cohen is more focused on snow cover in Siberia.