Gao et al. in a study this week in GRL modelling precipitation in Europe under increased greenhouse gases:
Changes in extreme precipitation events and dry spells suggest not only shifts, but also a broadening, of the precipitation distribution, with an increased probability of occurrence of events conducive to both floods and droughts.
Looking at this they’re talking about some major floods in the southwest US during the Holocene (as well as a bunch of other very interesting info). In your drought studies, have you run across the actual years of those major floods?
They also talk about a south to north migration of the Holocene maximum, which it seems to me would follow slower warming up north due to melting of the ice sheets.
The last sentence about the Holocene is most profound, as they say.