Thursday, November 3, 2011

NAO Ensembles Head for Negative Territory around Mid-November

Pre-reading notes: The NAO is a variating index which takes into account a semi-permanent high pressure system over the Azores (Azores High) and a semi-permanent low pressure system over Iceland (Icelandic Low). The higher the pressure differences are between this high and low means a +NAO index, while a low difference is a -NAO. -NAO typically gives cool air to the North US and areas around the region.

NAO tracking ensemble models are now in a consensus to head into negative territory beginning mid November. While that is not the official start of Meteorological Winter, it is around the time the Midwest, Plains begin to see their chances for snow significantly rise.
We will carefully watch the NAO and all other variables as we track this potential.


Mike Paulocsak said...

Hello Andrew.When the NAO goes negative,does that mean the chances for snowstorms rise?I'm just learning this type of thing with winter weather,so don't think i'm crazy please.

Andrew said...

Mike- I don't think you're crazy: it took me a while to learn and i'm STILL learning about all the ins and outs of the NAO.
When the NAO goes negative, yes, storm chances for the East Coast/Ohio Valley increase.