Look at that cover picture and you can see just how busy the Pacific continues to be this year! And the GFS model suggests that it will stay that way through at least the middle of the month:
The Atlantic, on the other hand, has been quiet since the beginning of July. Our last named storm was Hurricane Elsa, so we’ve gotten to five storms -- not that anyone is complaining. The same GFS model from this morning keeps the Atlantic basin quiet through August 18th. Disclaimer though -- these models are much less accurate after about day 8.
One factor that I’ve discussed several times is the Saharan dust and, as of today, there is still plenty of it:
Another factor is what’s known as the Madden-Julian Oscillation, or MJO.
What’s the MJO?
Back in the early 1970′s, Dr. Roland Madden and Dr. Paul Julian were studying tropical wind and pressure patterns when they discovered a pattern of winds that oscillated around the globe correlating with increased rainfall when that pattern showed up. The winds, humidity and water temperatures, along with rising or falling air either increased or suppressed rainfall. So when the MJO is present, the chance for tropical weather is enhanced because more thunderstorms over tropical waters are the seeds for hurricanes. You don’t HAVE to have the MJO present, but it helps fire things up.
When the MJO is not around, there tends to be less rainfall and fewer tropical storms. So how often it shows up becomes an important question as it travels all the way around the globe in about 48 days (sometimes faster or slower). So the enhancement for the tropics to get active in any one spot is usually 1-2 weeks. Where is the MJO now and where is it going? Don’t let this graphic blow your mind:
The MJO moves EASTWARD and while last week it was over the western Pacific (remember those typhoons threatening China and Japan), the European Forecast (ECMWF) indicates increased tropical activity in the Eastern Pacific. As if that area hasn’t been busy enough.
The MJO will move continue to move eastward around the globe and the middle to end of August will be over the Atlantic and that is when I expect we’ll see the tropics in our part of the world really rev up.