The Effect of the MJO on the North American Monsoon*

David J. Lorenz, Dennis L. Hartmann
2006 Journal of Climate  
The effect of the MJO in the eastern Pacific on the North American monsoon is documented using NCEP Reanalysis and daily-mean precipitation data from 1958-2003. It is found that westerly zonal wind anomalies in the eastern tropical Pacific lead to above normal precipitation in northwest Mexico and Arizona several days to over a week later. This connection between the tropical Pacific and monsoon precipitation appears to be limited to regions influenced by moisture surges from the Gulf of
more » ... the Gulf of California as a similar connection does not exist for New Mexico precipitation. The evidence suggests that the MJO affects monsoon precipitation by modulating the strength of easterly waves off the coast of Mexico, which in turn trigger the development of a gulf surge.
doi:10.1175/jcli3684.1 fatcat:kzwt7garajgzjfsqmj24c4csh4