Brian Bledsoe

Just as a refresher, the MJO or Madden-Julian Oscillation is an eastward moving
disturbance of clouds, rainfall, winds, and pressure that traverses the planet
in the tropics and returns to its initial starting point in 30 to 60 days, on
average. 

There can be multiple MJO events within a season. So, the MJO is best described
as intraseasonal tropical climate variability (i.e. varies on a week-to-week
basis). It is different from El Niño or La Niña, because those phenomena remain
stationary within the ocean and persist for several months. 

The graphic below is a good representation of what the MJO is all about.

Depending on what phase it is in, it can bring periods of wet or dry weather to
various regions of the globe. Why is this important? Well, right now a very
strong MJO pulse just exited region 8 and is moving through region 1. The green
line on the graphic below is the general forecast of what it should continue to
do.

The farther away from the center of the diagram the lines are, the stronger the
pulse, and the more potential it has to greatly influence different regions of
the globe. Again, that could be with warmer/colder or wetter/drier weather. The
graphics below show (generally speaking) what type of weather is associated with
each phase, during this time of year.

Precipitation

Temperature

The current phase of the MJO is very much responsible for the wet/cold weather
we experienced to finish the weekend and to start this week. It's a good
thing... despite it snowing on May 3rd! 

For Colorado and other parts of the region, this can set us up for periods of
wetter than average and cooler than average weather. Let's see what the model
ensembles say for the next 10-14 days.

Euro Ensemble Mean

Temperatures

Precipitation

GFS Ensemble Mean

Temperature

Precipitation

Generally speaking, the 10-14 day forecast maps are not too far off from what is
normally expected with the MJO in the current and forecast phases. Relatively
wetter/colder than average conditions can be expected for much of the Plains,
with MUCH wetter than average conditions expected in parts of the Mississippi
Valley. 

We'll continue to watch this, but at least for the next couple of weeks (present
storm included) much of the region along and east of the mountains will likely
have some recurrent chances for moisture. Hope this makes sense, and helps you
envision of what potentially lies ahead.

Status of the MJO and potential impacts on our weather