|Posted by Delaware Valley Weather on November 3, 2012 at 8:00 PM|
Well folks it's been almost 3 months now and you've all waited patiently for it! Our winter forecast is finally here! It took us a very long time to put together our thoughts on what each month will be like this winter. Several analogs and scientific investigation occurs during research like this. To make it easier for our viewers to understand, we will not go over many of the signals but for the most important ones. Some of you may have heard of the NAO, AO, and PNA (North Atlantic Oscillation, Arctic Oscillation, Pacific/North American). Now, these three teleconnections are vital for determining the track, intensity and type of storm that affects our area. For snow in our area, you would want a negative NAO and AO and a positive PNA. Although, the forecasts for these factors go out to about 2 weeks. Therefore, it is difficult to determine what and how these signals will play into our winter storms. Fortunately, there are other signals that can tell us how the NAO, AO, and PNA are looking. Right now, the NAO and AO look to stay relatively negative throughout the winter, but this does not mean they will be positive at times. A few other signals that have a major role in our winter weather are SOI values and the PDO. SOI values tell us where the El Nino is (weak or strong) in comparison to water temperatures in the Pacific. The PDO are the actual temperatures of the Pacific Ocean and the sea pressure. As of now, temperatures in the Pacific are rising signaling an El Nino has started to form. So, how does this all help us forecast the winter ahead? Well, meteorologists like us look at years previous to see if there are any similarities between historic years and now. The closest this year comes in comparison to other winters is 2002-2003 where there was above average snowfall for the whole area. We might also ask ourselves "In 1980 was the PDO around this level?" or something along those lines. Throughout our time analyzing models, teleconnections, and patterns, we have finally come to the conclusion that this winter will be a Weak El Nino. Take a look at this quick graphic for the past ten years of snowfall in the city of Philadelphia. After each below average year, we bounce back to an above average year. Sense a trend? It may continue this winter!
How many storms will we receive (between December & March)?
- 4 Major Nor'easters
- 3 Alberta Clippers
- 2 Apps Runners
- 2 Suppressed Storms
- 1 Great Lakes Cutter
So....what does that mean? Well folks that means an ABOVE AVERAGE winter in terms of snowfall and BELOW AVERAGE temperatures. Below you can find our thoughts month by month. In our second to last image, we give our predicted snowfall amounts for selected cities. Hope you all enjoyed reading!
December Temperatures & Snowfall
January Temperatures & Snowfall
February Snowfall & Temperatures
March Temperatures & Snowfall
Overall Temperatures & Snowfall
Categories: Winter Weather