Wednesday, October 12, 2016

My updated and final winter 2016-2017 outlook:

I issued my early winter outlook quite some time ago.
I've never issued a winter outlook that early before.  My outlook for winter 2015-2016 was just about dead-on. One issue last winter was the near record El Nino overriding most of the teleconnections.  Many of the factors from last year are still with us...but one major one is gone, El Nino. Winter 2016-2017 will feature a  El Nino-Southern Oscillation (ENSO) neutral , to weak La Nina. Therefore the other teleconnections and indicators won't be washed out.

The PDO is going to be warm. So this will allow for the western ridge and the eastern trough This was the same type of setup we saw in 2013 and 2014. For the first 10 days of October we saw a rapid expansion of Eurasia snow cover. If this rate continues for the last half of October, this would be a sign for a cold Northeast winter.

Snow cover in Eurasia and Canada is a little above average for this point in October. What I look for is the expansion rate below the 60 degree mark. comparing 2015 and 2016 you can see there is a lot more snow south of the 60 degree than last year at this time. The faster the expansion the colder the winter should be in the Northeast.   I expect to see snow cover in Eurasia, Russia, and Canada to increase a lot over the next four weeks.

Here is the Euro Ensemble showing what it thinks snowfall will look like by Thanksgiving.  it does show quite a bit for northern New York and northern New England....but remember the chart shows total snow falling by that date.... not snow depth on the ground....snow will come and go....but to see this much snow falling in November is above average.  So we could see a couple of storms in November.


Over the last 10 years, the Northeast and Mid Atlantic has seen a large uptick from the impacts of major snowstorms. Here is a chart that shows how the snowstorm frequency is increasing. There is also a chart by Joe D'aleo that shows almost half of the major storms to impact the Northeast and Mid Atlantic have occurred during the last 10 years.

                                              Joe D'aleo

Weak La'nina winters tend to see above average upstream blocking, So the storm tracks shift south placing the Northeast into the Mid Atlantic in the cross-hairs for big snowstorms. 

There hasn't been any change in my thinking from the early 2016-2017 outlook I posted.

Analog years: are still 1958-1959,1959,1960, 1960-1961, 1977-1978,1981-1982,1993-1994,1995-1995,1996-1997,2000-2001,2013-2014, 2014-2015.

The top five are.....1960-1961, 1995-1996, 2000-2001, 2013-2014,2014-2015.

This upcoming winter should be quite cold. My winter analogs are colder than my forecast, this is due to the warm Atlantic. This winter should shape up like the cold winters of 2013-2014 and 2014 and 2015.

The warm waters off the Northwest Coast into the Gulf of Alaska will be the major driver for this winter season

That warm Atlantic will hold winter at bay for the first part of winter. As I've been saying for a long time, October is going to be well above average in temperatures....November will be above average as well, I do expect to see a few snow events in November, but nothing lasting.  One thing seems evident to me, we're going to see an abrupt change to winter this season. I'm not sure when this will happen. For this reason December is tricky. Those warm Atlantic SST could allow for the last part of December into the first half of January quite warm.....I think December will end up with overall temperatures being average. With the real cold building in for January, February, and March.

As we've seen this Summer (which was exactly like I said it would and dry) The warm Atlantic helps promote a eastern ridge in the Summer. This same thing will be the case for October and November. But after awhile the warm Atlantic becomes our winter friend.....the warm Atlantic should help lend moisture and warmth to promote quite a few storms.  With the cold in the Midwest into the Northeast....we should be ground zero for the battleground between the two. So if we can get some decent blocking from time to time.....we could see a few severe Nor'easters.  Often during a weak La Nina, the Southeast U.S. sees a warmer winter, due to some ridging. So I don't think the eastern trough will be as deep as we saw in 2014-2015. So while cold, we most likely won't be quite as cold overall, as we were in 2014 and 2015. The blocking this year most likely won't be locked in; so location of the block will determine when we see warm ups and cool downs.   

This is going to be a big lake effect winter...I expect well above average lake snows this season...Of course, lake effect is dependent on wind direction, so not all areas in the lake snow belts will see well above average snow amounts....but the lake snow regions will see heavy snow on average.  We most likely will see some big lake events earlier in the season.
There are no changes to the charts I posted in the earlier outlook.........