Sunday, January 24, 2016

The Big East Coast Snowfall

Global warming paradoxically increases the chances of large snowfalls, at least until the global temperature goes low enough to turn it into giant rainfalls.  As explained here, by Michael Mann
“There is peer-reviewed science that now suggests that climate change will lead to more of these intense, blizzard-producing nor’easters, for precisely the reason we’re seeing this massive storm — unusually warm Atlantic ocean surface temperatures (temperatures are in the 70s off the coast of Virginia).”
When you mix extra moisture with “a cold Arctic outbreak (something we’ll continue to get even as global warming proceeds),” as Mann points out, “you get huge amounts of energy and moisture, and monster snowfalls, like we’re about to see here.”
When I was young living in Spokane, the air was dry and we had frozen-over lakes without snow on them.  Really cold air is dry air.  Warm air is wet, and global warming means wetter air.  There's a "sweet spot" where the air is not to cold nor too warm, and that's when large snowfalls are going to happen.  And they have the last two years in the Northeast, and probably will there for some years to come.  
the fact is that the warming to date is not close to that needed to end below-freezing temperatures during midwinter over parts of the globe like New England, while it is large enough to put measurably more water vapor into the air.
Assessment of the January-February temperature conditions again showed that most of the United States had 71%-80% of their snowstorms in warmer-than-normal years…. a future with wetter and warmer winters, which is one outcome expected, will bring more snowstorms than in 1901-2000. Agee (1991) found that long-term warming trends in the United States were associated with increasing cyclonic activity in North America, further indicating that a warmer future climate will generate more winter storms.
Here in the Pacific Northwest El Nino has brought a lot of snow to the Cascades and further East. But without an El Nino, there isn't much snow.  Last year the Cascades had the worst ski season ever, but a great one this year.  But next year probably won't be very good for skiing and by the time of the next El Nino, the temperatures may be too warm even at that altitude to make is snow instead of rain.

In the meantime, here west of the Cascades, the plants already think it's spring with March-like temperatures.