MJO Rolls Across Pacific Toward Atlantic To Ignite Mid-south/Brazil Heavy Rains

Fig. 1: The Madden Julian oscillation 14-day forecast reveals a surge of equatorial convection from near the Dateline the next few days into the Atlantic tropics in early December.

Discussion: Forecast models reveal presence of MJO convection concentrated near the Dateline through the weekend surging eastward toward and into the equatorial Atlantic in early December (Fig. 1). The influence on climate is heavy rainfall across the Mid-south (and vicinity) in the 10-day U.S. precipitation outlook (Fig. 2), enhanced rains across Brazil (Fig. 3), and a rare drying trend in Australia (Fig. 4). The Mid-south U.S. rains should benefit low water levels in the Mississippi River Valley. In Brazil, any drought risk is squashed by the MJO-driven rains and already wet soils in Southwest Brazil and eastward trend wetter. The east-shifting MJO allows Australia to turn drier which is a rare event in the La Nina-driven wet climate of the past several years.

Fig. 2: GFS 10-day precipitation amount forecast across the East U.S.  

Fig. 3: GFS 10-day precipitation amount forecast across Argentina/Brazil.  

Fig. 4: The 8-14-day percent of normal rainfall forecast across Australia.