Updated Winter 2008-09 Thoughts

Winter 2008-2009

Everyones favorite time of the year. Winter. Winter 2007-08 has left a bitter taste in the mouth of many as that winter will be remembered as the winter with less then normal snowfall in the mid atlantic and warmer then normal temperatures as well. The exception to this was New England where areas recieved record snowfall. This created somewhat of a rivalry that winter season between those that lived in the New England Area and those that lived in the mid atlantic.
Last winter we were looking at a few factors that made the winter play out the way it did...
1. Above normal temperatures were attributed to two things.
A. The North Atlantic Oscillation which last winter season ended up being remotely positive (+)
B. We were under the influence of a strong La Nina.
We were depending on a stratospheric warming in the higher levels of the atmosphere to make it to the lower atmosphere in order to bring in colder temperatures. This proccess happened but never propagated down to the lower levels of the atmosphere, until a little too late...the winter season had passed. We also, could not really obtain any "true blocking" over Greenland and this was also attributed to the NAO remaining positive during 2008-09.
So the lessons that we can learn from the above are when you have a strong La nina and absolutely no help from the North Atlantic Oscillation...you are going to have a winter with less snow and milder temperatures if you are in the mid atlantic. The northeast made out better because of the location being closer to the cold high pressure areas and the fact that they never dropped south but more slid off to the east and off the northern new england coast.
Historically speaking, a Strong La Nina winter is almost always followed by a Neutral Enso or a weak La Nina. So this winter I am expecting a Neutral Enso with fall back effects from a La Nina.
Looking at the summer pattern is an important step when forecasting your winter. The blocking that we could not obtain winter of 2007-08 we have obtained during the summer of 2008. June we started off with extremely warm departures for the first half and ended the 2nd half with negative to seasonal departures. The month of July can be summed up in seasonal to below ...and august can be summed up as below normal in pretty much all locations. This is largely attributed to two things...
1. The North Atlantic Oscillation has been Negative since April of 2008
2. The PNA has been positive.
Whenever, you have these two factors in tandem of negative and positive...the result is a ridge on the west coast and a trough on the east coast. Hence keeping temperatures cooler then normal and locations inside the trough wetter then normal. There have been times of relaxation and that is what is referred to as a reloading pattern. This occurred in the first half of September of 2008. However, as these two weeks passed...temperatures have gone back to seasonal if not below seasonal normals..with the exception being the 21st of the month.
This is what i refer to as the wash, rinse and repeat cycle. Looking at the patterns now and the teleconnector signals..I see nothing to remotely suggest a change to this pattern. So heading into winter season of 2008-09...I am looking at a better then average winter. It can not get anyworse then last year , correct?
The NAO should continue to be predominately negative while the PNA should continue to be predominately positive. The AO should also be on the negative side as this is what relays cold air from Canada southward via the northern Jet Stream. The northern Jet stream should be more active this winter season. Not only in allowing colder air from Canada to penetrate the USA but also in sending waves of low pressure known as Alberta Clippers south and southeastward thru the Northern USA states.
While the Northern Jet Stream will be active..I also am expecting the southern Jet stream to be active as well...sending waves of low pressure in from the california coast and dropping down into the G.O.M and riding up the coast either off the SE Coast or up the Eastern Sea board.
Temperatures across the Northeast for the months of November, December and January could be as low as 2-5 degrees below seasonal norms. So a colder winter is on tap for the Northeast. Possibly record setting cold for december and January. However..while this appears to be what a winter lover wants...it does have its downside. This intrusion of cold air...if you want to use the phrase "record cold" will cause suppression of the storm track. This does NOT mean the Northeast will not get snow..what it means is that, unlike last year where every storm brought snow, this year it will be more a case of will it make it far enough North?? The answer in my opinion is that the areas that made out last year will be lacking this year compared to normal. In other words the Northeast should obtain about 75% of there normal snow fall. February will see average temperatures and average precipitation.
Temperatures across the upper mid atlantic are going to range as much as 1-4 degrees below normal. Temperatures across the lower mid atlantic will range anywhere from 2 below normal to seasonal levels. The suppression of the storm track that is going to keep the northeast from obtaining as much snow is going to cause the upper mid atlantic and the lower mid atlantic to be on the "brunt" end of the storms that do occur. The upper mid atlantic should obtain 100-125% of there normal snowfall. While the lower mid atlantic should recieve 100-150% of there normal snowfall for the season.
As i stated there will be times when the seasonal pattern relaxes and it is during these times that all areas could be on the recieving end of ice storms. It will be during these times that the temperatures will get to more of a seasonal level ...and any storms that arrive during those times would result in ICE because of the ground being so cold, despite possible air temperatures of 32-33 degrees.