Friday, September 14, 2012

A Winter Outlook Update

Hi it’s Rebecca again, I thought I would give a quick update on how the oscillation’s and Teleconnections are shaping up.

As I pointed out in my preliminary 2012-2013 winter outlook, it looks like this will be an El Nino winter. The data coming in for September is still showing that a weak to moderate El Nino is quite likely.The El Nino would kick in during the October – January timeframe.

As you can see in the Graphic on the left. there is warming going on in the equatorial Pacific. There are indications that warming is starting to occur in the central and western Pacific. If the El Nino does indeed become west based, it would have major implications for our winter weather in the Northeast.

East based vs.. West based:

Believe it or not, a west or east based El Nino makes a huge difference in weather on the East Coast. During an east based El Nino the wintertime temps are normally warmer. Whereas, a west based El Nino normally has much colder temperatures, especially in the Northeast.

Here are a few years that we had an east based El Nino

1951-52, 1972-73,  1991-92, 1997-98, and 1986-87

Here are a few years that we had an west based El Nino

1957-58, 1965-66, 1982-83, and 2002-03

The Strength:

The strength of an El Nino makes a world of difference. Weak to moderate El Nino’s pose a greater threat for a heavier winter, in the Northeast; this is because the setup allows storms to dive into the Southeast, where they pickup a lot of moisture, then move into the Northeast drawing in cold air as they move north….However, normally a strong El Nino will cause the temps to be warmer.
A weak El Nino generally means a snowy winter for the East Coast.
A moderate El Nino leans toward a average wither on the East Coast.
A strong El Nino typically brings less snow to the East Coast.

Years that featured weak to moderate El Nino conditions

1977-78, 1992-93, 2002-2003, and 2009-10

Of course the NAO and AO would have to play along. The vast majority of the models are showing a negative NAO. However, as I said in my preliminary outlook….this might not be the case…..But I’m starting to lean in the negative NAO direction.

The PDO will be positive this year. During the positive phase of the PDO, the Northeast sees a decent winter.

Here is a look at the current sea ice conditions. There has been a large increase in the amount of ice over what we saw last month. I will have a better Idea what the snow and ice looks like as we get closer to winter.

Right now, I think we will see slightly cooler than average temperatures with at least an average snowfall. The setup does favor more Nor’ Easters. Therefore southeast NYS and southern New England could do well. I still have a few things I’m trying to get a handle on. But, I’m confident we won’t see a snowless winter like we had last season.

If you want to see a cold and snowy winter; hope for a negative NAO to go along with the positive PDO, and west based weak El Nino.

I should have my final 2012-2013 winter outlook posted in three or four weeks.


1 comment:

Thank you for taking the time to comment, I will answer as soon as I can.