The forecasters who create these long-range models are still basing the short term summer/early fall warmth on a number of extended forecast models that concur with the heat.
As for late fall and winter, the orange/brown warm/dry blobs are based on the idea that a weak-to-borderline-moderate El Nino will develop this fall. The latest indications there are for a bit more uncertainty now about the El Nino's strength than in recent months, but trends are still pointing toward weak-to-moderate event.
The forecasters warm there is still a chance the event could end up stronger than predicted -- or revert back to neutral conditions like we saw in our last El Nino event, but say highest likelihood is still the weak to borderline-moderate scenario. They did say the slimmer chances of the strong event are even a little slimmer now than they have been.
El Nino's tend to make for dry and warm autumns...and especially winters around the Pacific Northwest, and that's where the forecast maps are leaning. Here it is in table format, and you can see the best odds for warm weather come in the mid-late winter months:
The models show El Nino should weaken and fizzle out by spring and thus no real signal is signified yet for next spring and beyond yet.
Remember these forecasts represent weighted odds for being cooler/warmer-drier/wetter than normal. Sort of how you can give higher odds the Mariners will win a baseball game if Felix Hernandez is pitching, but -gasp!- the Mariners do occasionally lose one. So put another way, let's just say El Nino is like having Felix on the mound for a warmer/drier winter!