Oct 01 2012

October Looks To set The Tone for the Upcoming winter…

When looking at the short and long range GFS models we are seeing extended periods of colder than average air temperatures spilling into the eastern half of the United States. While the NAO, AO and PNA remain inconsistent The General theme for the NAO has been to remain negative. I think soon the AO will follow suit. Its actually good that the NAO has been not been dominantly negative, and around the 0-2 range in negative. Why? Well because if it is too negative, yes you will have cold air, but it will end up pushing or suppressing the southern jet stream too far south and will not allow for any winter weather to develop over the eastern half of the United states. So its actually good that the NAO is hovering around where it has been.

And another positive sign is that the GFS model is hinting at a coastal low developing next week. While it is far to warm now to produce snow, if it were December we may be talking about a good 3-6 inches of snow from DC, to Baltimore, To Philadelphia and New York City. Seeing things like this is the type of pattern that you want to see. Notice on the Model there is not hovering Low pressure system hanging over the Great lakes that holds the warm air in place but instead a firm area of cold air that could be wrapped into the storm system, This is what we want to see if you like snow in the Mid-Atlantic and Northeast and I really think that this October will be a sign of things to come this winter.

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About the author

Dante' Brown-Royal

Hello, I am Dante' the CEO/President of Weather Advance. I most of the time specialize in Winter Weather and winter forecasting. I also am pretty decent in predicting severe weather and tracking hurricanes. Howevere usually that's not my forte. I will strive to always give you the most accurate updates possible, and information possible when it comes to the weather!

2 comments

Jason Shaulov

October 1, 2012 at 6:21 pm (UTC -4) Link to this comment

Nice post Dante I noticed that on the GFS as well seems like this winter may be a very good one
Eric

October 1, 2012 at 9:50 pm (UTC -4) Link to this comment

Good job picking up on this Dante, I have been noticing this for several days now, and the reason we are seeing this cold is because there is going to be a lot of blocking high pressure over Alaska and NW Canada in a few days and lasting through at least the 12th or so. Some of the models suggest this blocking may reach well into the arctic, and I wouldn’t be too surprised if it happened, and if this kind of blocking over the arctic persists into the winter what may occur over time is that the higher pressures may begin to disrupt the polar vortex and disruptions in the polar vortex have been known to be a large contributor to setting off stratospheric warming events (SWE’s). When you see a SWE in the winter time, especially when the ENSO index is favored towards el nino and warm neutral, it is a signal for colder weather over the US. SWEs are the types of events that can really produce a lot of cold air, and if there is a blocking pattern in place, like a -NAO for instance, the US will likely feel the effects of it about 10-15 days after its formation, because there is a large amount of lag time between the actual formation of SWEs and the resulting cold air mass that it produces from expanding the lower end of the stratosphere and forcing the troposphere to contract. That contraction of the troposphere leads to cooling, and the colder air takes up less space, and as the troposphere continues to contract, it only helps to further allow for more expansion of the stratosphere and strengthen the SWE. I get real excited when I see SWE’s in the winter because I know someone is about to really get clobbered with cold.
I look at the 10hPA level (hectopascals) or (about 85,000 feet above sea level) for trying to determine when and if an SWE will form. Here’s a few links that might be useful in the future.
http://www.daculaweather.com/stratosphere_temp.php http://www.daculaweather.com/stratosphere_height.php
http://www.daculaweather.com/strat_details.php http://www.daculaweather.com/4_stratosphere_temp_ecmwf.php