To gain a clear perspective to the winter of 2009-2010 , I feel its pretty much important to look at what has been occurring over the summer and early part of fall.. Pretty much what has been the dominant pattern? What teleconnections have been essentially controlling the weather? . Basically since May 2009 we have been under a pattern that has been controlled by a Negative NAO (to neutral) a Negative EPO (to neutral) and a Positive PNA (to neutral)..This has been essentially the pattern that we have been being dominated by. This pattern was responsible for a relatively up and down summer and perhaps one could say more down then up? The Year that will be remembered as the Year Without A Summer to many across the Northeast. So what happened during this time period?
The month of May 2009, we ended up pretty much above normal temperature wise across the region. There will always be a small area of exception to this rule.
Then along came June and July 2009 ..that swung the pendulum in the opposite direction, back to below normal temperatures.Now what happened come August of 2009?
Another relaxation period had taken place. The temperatures swung the pendulum once again. The month of August ended up above normal.
Proceeding on this pattern..my calculations had pretty much put September into the below normal category,as well as put October 2009 into the below normal category across the region. Above is October to date.
Following this pattern recognition, this implies that we should have a relaxation period for the month of November..where temperatures will be above normal.The CFS actually shows this occurring.
Then back to December & January Below normal. Wash, rinse and repeat.
The above pattern is what I have referred to as Trough Zonal Trough. Essentially meaning that there will be thru out the month troughs across the east, followed by zonal (relaxation or reloading) followed by troughs again. I have called this pattern the T.Z.T pattern.
Looking at el nino years 1970,1972,1974,1975,1976,1977,1979,1981,1982,1984,
985,1986,1992,1996,1997,2000,2004. Out of the above el nino years..seventeen total, 9 of the 17 winters following a cooler then normal summer..came out colder then average. So this is better then 50% of the winters came out colder then normal.
This brings me back to the month of October 2009. As research by N.W.S Rainshadow (Tony) has showed 16 out of 17 Winters that had an October colder then normal ended up with a winter that was colder then normal.
In addition to the colder then normal month of October we have also had some other records set for the month. Five records alone were set in one single day in State College Pa with a Historic Early Season snowstorm. So, in some sense, the potential for historical cold and snow that I was talking about has already at least partially come true. Places in MD, October 17th received there earliest snowfall in many, many years & would not be surprised if those were also Historical records broken. Also the B.W.I airport had there lowest daily high temperature on record ..which broke the 1871 record on the 16th of October.
As far as the El Nino is concerned.. I still do not think that this El Nino is going to peak past Weak. It would take some pretty major warming to have this El Nino come out with a Tri Monthly average of 1.2 or higher. So i believe we will maintain a weak El Nino ..although Nino Regions 3.4 and 4 could warm some more. The SOI is negative and should pretty much balance itself out between negative to neutral.
The PDO. It is a basic given that the PDO during El Nino falls starts to warm up. So we have a warming PDO. This is a KEY factor to the winter coming up. Essentially every cold El Nino occurred with the PDO warming in the fall months. September PDO value was 0.52..prior months to that were Aug 0.9 and July -0.53. See here<---
With the El Nino maintaining or strengthening and being in the fall months. my calculations show that October PDO should come in slightly more positive then Sept PDO.
West based or east based El nino? Essentially with the warmest waters in regions 3.4 and 4..we are currently dealing with a West based El Nino and I pretty much expect that to continue thru out the winter.
Weather Pattern as stated above has been pretty much controlled by T.Z.T and that is the pattern I expect to maintain itself thru winter. This pattern will be pretty much a -EPO +PNA and -NAO. This pattern will have times thru out the winter months where it will have to relax and reload. Its during these times that we will experience a positive NAO, a neutral to negative PNA and a positive EPO and a +AO. However, during these relaxation times, cold air will build up in Canada and then when the pendulum swings back to the dominating pattern the cold air will release into the USA and the dominating -EPO + PNA -NAO will return.
Storm tracks.
I am anticipating the southern Jet Stream to be quite active. This will lead to a good amount of storms forming in the GOM and then riding up and along the eastern seaboard. Not all them will follow all the way up the coast, as is pretty common with El Ninos, we will also have our fair share of Southern Sliders. The other two storm tracks will be Alberta Clippers that drop down out of the Midwest and then reform off the east coast..And still yet one more track would be what I like to call bowling ball systems. These are essentially storms that at the Latitude they enter, they move west to east and exit off the east coast at essentially the same latitude they entered on the west.
Analogs used were 1904-1905, 1977-1978, 2002-2003, along with past weather history, including recent weather history.
So with that all said here are the revised, updated...final outlook. I do realize that there are some that are not going to agree with the images in this post. That is completely fine. However...this post and out look contains a lot of history in it to support the forecast.
No comments:
Post a Comment