Thursday, September 13, 2012

New Fall Pattern Setting Up; New LRC Pattern Evolving?

The latest model and ensemble forecasts for North America are showing a new fall pattern appears to be setting up.

As you can see above, this is the latest GFS forecast of 500mb height anomalies from the University at Albany. We can see two sets of high pressure ridging setting up across the area to the south of Greenland, as well as a strong ridge over eastern Alaska and western Canada. This ridging enables a strong low pressure system to sit in place and strengthen over the northern Plains and Midwest. We have not seen a pattern like this in the past 2 months. The lack of such a pattern's recognizance may suggest that the Lezak Recurring Cycle is changing. Here's a few pointers on the LRC.

*An annual pattern that starts in Fall and dissipates in summer.
*The pattern runs in cycles that vary between 40 and 60 days for each cycle.

Looking back 40 days, we are not seeing anything close to what is being projected here, indicating that the new LRC pattern for 2012-2013 could be setting up for the nation. That said, this same storm system and ridging may happen again in the next 40-60 days.

Also, the North Atlantic Oscillation (NAO) and Arctic Oscillation (AO) look to be heading negative in the future, indicating cold weather is on the horizon for the nation.



mike paulocsak said...

Hello Andrew and all the other followers on here.This could be the start of something big,if you know what i'm talking about.A winter full of snow/cold!

WinterStorm said...

Hi Mike! I know what you're talking about! Andrew, you're well on track to making 1,000,000 page views pretty soon! Congratulations! You've come so far since two years ago, and thank you for your hard work.

mike paulocsak said...

Hi WinterStorm.I'm thinking it will be a very interesting winter for many of us.

Anonymous said...

Looks good for Colorado for once :)
Bring on the cold and snow!

Josh Herman said...

Andrew, I am not convinced that this particular comparison can be used as a determining factor of a new pattern. If you follow this particular pattern back through the cycle you will notice a pattern that has seasonal troughs within it.

What I can agree on is, the patterns are transitioning and new energy is either being introduced or taken away and the 2011-12 LRC is nearing an end.

Check out the calender ( and a few entries on the AccuWx LRC forum. What do you see?!

Andrew said...

Mike: This is proving interesting.

WinterStorm: It has not been as long as I thought it would be, which is good, because I love doing this.

Josh: It's great to see you stop by! I agree that new things are being seen and features are being tweaked and fixed. This will certainly be interesting to see evolve as we head on into winter- the LRC is such an invaluable resource, I can't wait to see the new cycle!