Madden Julian Oscillation on the Move; Warms U.S.

Fig. 1: The latest 2-week forecast of the Madden Julian oscillation indicates moderate intensity shifting east from phase_4 to phase_6.

Discussion: The convection phase of the Madden Julian oscillation (MJO) is forecast to shift eastward (Fig. 1) from Maritime Continent in early February (phase_4) toward the Dateline as middle third of February arrives (phase_6). The MJO projection across the locations identified favor a warming (Pacific maritime) influence on U.S. climate (Fig. 2). In the tropics, the eastward MJO shift supports a wet climate shifting across Australia while the climate bias in Brazil is drier than normal (Fig. 3). The eastward shift of the MJO toward the Dateline usually inspires above normal wind speeds in the middle latitude jet stream across the Pacific Ocean generally associated with positive phase of the global atmospheric angular momentum (+GLAAM). Interestingly, the recent very negative GLAAM, well-correlated with the deep upper trough causing the U.S. arctic outbreak in January, is forecast to continue although weaker (Fig. 4). Forecast models are predicting steady positive phase southern oscillation index (+SOI) through the next 2 weeks which should turn negative given the MJO forecast. If SOI flips negative, positive GLAAM should emerge increasing the risk of a warmer U.S. pattern ahead.

Fig. 2-3: The MJO forecast of phase_4 to phase_6 favors a warmer U.S. pattern and convective rains (blue) shifting across Australia.

Fig. 4: The 14-day global atmospheric angular momentum forecast remains in weak negative phase.