Phil Klotzbach and Bill Gray of Colorado State have noticed a connection between tropical activity in the Atlantic and a global weather pattern called the Madden Jullian Oscillation(MJO). The MJO is a wave energy that propagates around the globe every 4-50 days. They have begun issuing two week hurricane forecasts for the Atlantic. Using model predictions, current conditions and the forecasted Madden Julian Oscillation, they have put together a forecast for the next 14 days. It is available on their web site at CSU. Typically if there is a strong MJO signal in the Indian Ocean, tropical activity increases in the Atlantic. This happens because wind shear slackens and upward vertical motion increases. A strong MJO signal in the Pacific can indicate reduced tropical activity here. Currently there is a VERY weak MJO signal as shown by the NOAA Climate Prediction Center(CPC) phase space diagrams. Earlier this month strong phase 4 and 5 signals were indicated, but in the past week that has changed dramatically.
Now the GFS ensemble forecast for the MJO through the next two weeks. The
thick green line is the forecast for the first week, and the thin line is the late
September forecast. These charts are available on the CPC site. A strong phase
3 MJO for next week(strong Indian Ocean could hint
at new storm activity in the tropical Atlantic in the next 7 days, although models do
not hint at anything unusual..
