The endless summer pattern steps out of October and into November, reinforced by a polar vortex split which favours a cold Eurasia but continued warm Lower 48.

For the East, this October, like September and August will go down as one of the warmest and warmest on record for some.

Having 1 of 2 pieces of the polar vortex displaced over Canada, supports low pressure and cold bottled in the north while warm ridging dominates beneath but as you can see from the below 10mb GFS temperature projection, the PV core appears to swing out of Canada into the North Atlantic while warming progresses towards Alaska from NE Asia but the 10mb level remains cold but not as cold. This could lift the Lower 48 high pressure dome NNW enough to allow a trough or negative to side in over the Southeast or Eastern US off the Atlantic. If this materialised, the dominant record warmth would at least ease and a colder pattern would kick in mid November on.

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GFS ensemble 5-day mean 500mb height anomalies show the retrogression of blocking high northward towards Alaska around mid November following the repositioning of the polar vortex into Greenland and North Atlantic and warming from NE Asia to Alaska/western Arctic.

See this morning’s video for more on the above.

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