I apologize for not having time right now to track down primary sources for you, but if you're interested in learning more about the current research specifical

I apologize for not having time right now to track down primary sources for you, but if you're interested in learning more about the current research specifically on this drought and climate, look up stuff related to the position and strength of the North Pacific High, how it's affected by the Arctic Oscillation (and decoupling of the AO from the North Atlantic Oscillation), and how those are related to extreme jet stream configurations (regarding which there is emerging evidence for a relationship with Arctic sea ice extent). And if you find good stuff, post the links!