After doing some quick analyzing of the current SST's, model data, and more specifically the overall N Hemisphere pattern, I am finding reasons that Autumn '19 is coming in fast and possibly hard this season. Firstly, I want to compare our current ENSO state, to the year 2017, to which, both years resembled ENSO neutral conditions.
Back in September 2017, the central PAC looks sorta similar to where we are now...
Our current SST's...while we are only in very late July, forecast models suggest cooling to continue across the central PAC as we approach Sept.
The big difference and what I believe will be the driver to our Autumn pattern in Sept, is the "warm blob" in the NE PAC. Back in Sep '17, one can argue the N PAC is quite opposite to the current state of affairs. If you look closely, the waters NW of Hawaii/South of Aleutians are cold presently and they were very warm in 2017. Forecast models continue this SST pattern from August into Sept and pretty much throughout the entire cold season. Why am I pointing this out? Back in Sept '17, the nation east of the Rockies was relatively very warm. In fact, I remember we had days in the 90's around here. Reason being, those cooler waters in the NE PAC produced favorable conditions to keep troughs coming into NW NAMER which flooded the nation across the eastern CONUS with warmth.
However, this year, I expect an entirely different pattern due to the SST's being quite opposite across the N PAC. In fact, recent guidance is now suggesting a big trough to inundate the eastern 2/3 rd's of the nation. Nearly all the variables one could imagine are pointing towards a short growing season, early frosts, active pattern, and possible first flakes up north??? The waters in the NE PAC are going to promote the NW NAMER ridge early and often this Autumn.
My senses are being heightened and I foresee a fast start to Autumn, one we really have not seen since maybe 2014. If the clues that I'm seeing continue, the new developing LRC in Oct/Nov will include blocking and an active northern stream along with some southern stream action later in November. I think the blocking wanes in November, as the Vortex strengthens significantly across N Canada and the Arctic/Greenland regions. This fits with the idea of the climatic changes I'm seeing evolving across the Arctic regions during the cold seasons of late and into the future. There will be a period later in Autumn where I anticipate Indian Summer and it may very well be in November when I think the high lat blocking fades. I really believe another spectacular weather pattern will be evolving across the central CONUS. While we gear up for our last month of Summer, signals for Autumn starting early way up north across the Archipelago are already showing up in the extended. A tell-tale sign that mother nature has something up her sleeves.