Updated Winter Forecast For Jan- Mar 2013

Two years in a row we have had to step back and take a look at the winter forecast and see what has gone wrong and revise that forecast. The first year was the 2011-2012 winter forecast and this year is going to be the second time where we have had to re-evaluate what was issued.

In the beginning it seemed pretty crystal clear that this winter was going to be a weak El Nino and we were not alone on this thinking as NOAA had issued an El Nino watch. Instead the warm waters faded and we were left with this...

As you can see region 3.4 is anything but warm and we are now into neutral territory. So, the much anticipated El Nino failed to materialize and we are left with a winter with a neutral enso.

So we need to step back and look at where we have been so far this winter of 2012-2013. 

The above is for the month of December and it has been a warmer then normal month over all across the northeast. This has been the case for the United States as a whole for the most part..

This once again is something that was not anticipated to occur this winter season and the reasons are pretty familiar to us after last winter.
1. A false Enso signal for the winter
2. Lower heights over Alaska 
3. A displaced polar vortex
4. Teleconnections just not where they should be to deliver the colder air ..
5. A lack of sustained blocking (though there has been some blocking)

A look very similar to last year & a pattern very similar to last year ..the only difference is the ENSO status. 
The teleconnections not favorable...

The NAO being positive...

The AO going positive ..

The PNA being mainly negative (now positive) but expected to dip back negative once again..

The EPO being mainly positive..

All these teleconnections are the exact opposite of what you want to see if you want cold and snow across the east in winter. Remember you want a - NAO - AO + PNA and a - EPO. When you have a - PNA with a - NAO and - AO this simply allows the colder air to go into the west coast and you get a west coast trough. 

Of course the wild card is always a SSW or a sudden stratospheric warming event. Of course this was the wildcard that was highly anticipated last winter and never showed itself and it seems that once winters take a turn south that card starts to get played because its the last hope for winter. And remember that a SSW has to propagate to the lower levels of the atmosphere and then it takes 2-3 weeks before you start to see any results of the SSW. So for example lets say one is starting now to occur.. and this would propagate down to the lower levels over the next week ..we would be looking at about Feb 1 or around there to start experiencing and seeing its results. 

So with all the above indicators ..we have re issued the winter outlook and we will continue to expect neutral ENSO conditions along with seasonal to above normal temperatures over vast majority of the country and below normal snowfall. With a - PNA we expect things could be below normal in the Pacific Northwest.  
This does not mean the east will not see any colder weather we just anticipate the shots to be more transient in nature. Of course a SSW could change this and the revised outlook then could go south as well but this seems to be the safest course at this point to take.