Following a very warm, dry summer, autumn flipped wet with the aid of increased tropical activity. Temperature-wise, it marginally held onto the mild theme in September with warm start followed by coldest 2nd half to a September (-NAO) since 2012 according to Gavin Partridge. It was cold in the east.

October saw the return to a neutral to positive AO/NAO which helped produce one of the warmest October’s on record. However, the wet theme continued from September.

Sept 2022 temp anomaly

Had it not been for a very warm opening week, September would have wound up below average for the UK as well as most of Europe. Stark contrast to last September which was the UK’s 2nd warmest.

Oct 2022 temp anomaly

Year-to-date temp anomaly

In the short to even medium range, frequent spells of wind and rain coupled with seasonable temperatures look likely. There’s good cross model agreement on a fairly classic Icelandic trough extending down over the UK and Ireland.

The CFSv2 shows the Iceland low over Azores high setup for November overall but note the strong heights over east Canada lifting up into W Greenland and the Scandinavia high in which the model hooks both up.

This could support more WNW flow, particularly later.

 

The latest run of the GFS ensemble for both AO/NAO backs the warm, wet CFSv2 solution.

Plenty of rain for western Ireland, UK, coastal Scandinavia.

Rain could be enhanced some by warmer-than-normal SST’s.

Colder, less wet 2nd half to November?

While a colder, less wet or stormy scenario for the mid and late portion of November is plausible, I don’t think this comes in relation for anything associated with the stratospheric polar vortex.

Here’s why!

Here’s the ECMWF 10mb zonal wind prediction.

Notice zonal winds according the the ECMWF are currently slightly below average but are about to strengthen. Also note that they could weaken back below average into the 2nd half of the month.

With the ECM suggesting a slight to moderate slow down of the zonal winds in the coming weeks, this suggests warming and the GFS sees this warming coming from Asia…

The warming causes some push and stretch of the circulation.

But that’s about it.

Unless some major weakening occurs within the next 1-2 weeks, any downward effects through the layers wouldn’t reach the 500mb pattern until nearer the end of November, more likely early December.

So, this DOESN’T get me too excited BUT this is worth watching for LATER ON!

Any colder pattern which occurs before the END OF NOVEMBER I BELIEVE comes from the tropics and not the pole. (of course of it’s the tropics which force such events as SSW’s but not just yet!)

In order for high latitude blocking to occur (and this is possible during the 2ND HALF of Nov), is likely to be triggered by the eastward propagation of the MJO pulse from Indian to Pacific Ocean. This too may bring a late flurry of tropical activity also.

-NAO’s caused by tropical cyclones driving heat northwards during September can see a repeat in the pattern down the road and this may be a classic example of this coming up in Nov.

Currently

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