Wednesday Weather Discussion: Looking at The Madden Julian Oscillation

Good morning. Quick post today as I do not want to bore everyone and get too technical. I want to touch on a weather pattern called the Madden Julian Oscillation (MJO). In simple terms this involves an area of thunderstorm activity that moves along the equator to into different regions. These thunderstorms have been shown to influence the placement of the jet stream. The  MJO has different phases and each phase relates to the area along the equator the thunderstorms are in. By tracking this, we can get a clue on what the weather pattern might be over North America.

Here is what a MJO diagram looks like...

Looks busy but its fairly simple. Each number is the region along the equator the thunderstorms are in and the line shows where the thunderstorms are heading. If the line is more on the outer bounds of the region its a stronger signal. Looking above you can see the European model says that these thunderstorms can move into a weak phase 4 as seen by following the green line.

Phase 4 means thunderstorms in this region...

This is not a cold phase for the east in the short term. Here is what the thunderstorms in this area tend to result in for North America...

Notice the cooler conditions in the southwest and mild conditions in the east. 

The models consequently are showing this for the 8-10 day period...

Looks similar eh? Doesn't mean it verifies as the model can be miscalculating where those thunderstorms go. Regardless its a factor that needs to be looked at. 

This does not mean we are having a warm December! It just means some mild air can come into the pattern for a week or so. I have absolutely no changes to my overall December idea of cold and stormy. If anything the factors I discussed yesterday will be the major drivers in the long term. I just wanted to point out that I look at everything and will acknowledge a warmer pattern coming when I see one, even if it is short lived. 


Thats all for now.