Saturday, November 19, 2011

Anticipated Mid-December Pattern Change May Come Sooner Than Thought

The ECMWF is showing a massive trough of low pressure entering the Upper Midwest area, indicated by a minimum of heights. The GFS is also showing a similar idea, but not as substantial as this. It is very possible that, should this verify, areas may receive blizzard-like conditions in the hardest hit areas. However, since this is 10 days out, let's not get ahead of ourselves.


-EPO will be turning positive. While that is not good for the area in question (Upper midwest), the EPO will be turning more neutral at the time period in question (Nov. 29).

-PNA will, after a VERY VERY prolonged and VERY VERY strong negative spell, be turning possibly positive. Should this happen, it would be very good news for the winter weather lovers in the East. Signs of this occurring are present in the above ECMWF image, as a ridge sets up in the West with a trough in the East- a major signal of a +PNA.

-NAO will be variating between positive and negative in this time frame. At this point, forecasts indicate that the NAO may be heading into weak negative territory, which wouldn't be of much help to the US for this system.


Mike Paulocsak said...

Hi Andrew.I just read this post.Does this mean winter will start to get into gear?Also,is there a chance that some storms could ride up through the Ohio valley and produce some heavy snowfalls over Ohio?

Andrew said...

Yes the winter will be getting in gear sooner or later. The Ohio valley will have their share of storms.

Shannon said...

You are seeing what a number of us are seeing, the beginning of the change into the Winter pattern. I have been maintaining for over a month now on my site, that I expect the Winter pattern to take hold between 12/4 - 12/10. In the Midwest area, we will see another strong warming, before the temperatures move to normal early December values. This is normal during a pattern change and is being verified by current forecast trends. Keep up the nice work Andrew, it is always informative.

Anonymous said...

Shannon, what is your website?

Shannon said...

Sorry for the delay in responding with my site anonymous, but I am not sure if Andrew would want me spamming my site name on his. I personally wouldn't care, as weather information is weather information, but I am not sure about Andrew's opinion. Maybe he can weigh in with his opinion.