Fig. 1-2: The Madden Julian oscillation 2-week forecast and general influences on U.S. climate (left) and international climate (right).
Discussion: Forecast models are in agreement as a progressive MJO shifts from phase_3 (Indian Ocean) to phase_4 and phase_5 (Indonesia/West Pacific) over the next 2 weeks (Fig. 1-2). Forecast intensity is moderate therefore influence on global climate is likely.
The effects on the U.S. climate remains favorable for more excessive rainfall in the Mid-South U.S. in the short-term and confirmed by most models. However, in the medium-range as the MJO shifts east and into the West Pacific support for heavy precipitation events in the U.S. lowers significantly allowing some relief for the vast flood-prone areas in the U.S. especially the Mid-South States.
The influence on U.S. temperature is colder across the northern U.S. with some late season snowfall helping to sustain the chill. South of the cooler regime in the North the MJO influence is warm across the remainder of the U.S.
Internationally, there are also important influences. In the short-term the MJO presence in the Indian Ocean fuels wet weather into western India. The MJO shifts east across Indonesia in the 6-10 day period fueling a wetter trend for both Indonesia and Australia. During the Indian Ocean to Indonesia shift the South American climate is likely drier than normal.
In the extended-range the MJO shifts east toward the Dateline. Associated with this eastern shift is wet weather risk increasing in South America while the previous wet weather regime in Australia and Western Indonesia fades.