Hi Scott, 

Thanks for your questions. Regarding the "warm blobs" you mention, most studies suggest that extratropical sea surface temperature anomalies generally do not have a major impact on the large-scale atmospheric circulation, so I suspect that the two warm blobs you mention did not have a major impact on Southwest U.S. precipitation. However, I would not rule out that there could be a minor influence, especially with NEP22A, since those anomalies are in a region that did seem to provide a minor enhancement to Southwest precipitation in the simulations I analyzed. 

The MJO certainly can interfere with ENSO, particularly during development of ENSO through the MJO influence on tropical westerly wind bursts. Perhaps more relevant for this discussion, the teleconnections forced by the MJO also can interfere with those of ENSO. From my experience, the superposition of the ENSO and MJO teleconnections can be treated as linearly additive, so the MJO influence (like what's shown here) can constructively or destructively interfere with the expected ENSO influence. 

Finally, the persistently positive SOI and MEI is an interesting observation. I also have noted that the tropical atmosphere has been more persistently La Nina-like than the Nino region sea surface temperatures in recent months. I don't have an explanation except to speculate that the multidecadal enhancement of the zonal sea surface temperature gradient (like what was described in this post) is helping to keep the tropical atmosphere more La Nina-like even when the typical ENSO sea surface temperature indexes are deviating from typical La Nina values.