Heading into winter it's time we start looking at what Mother Nature holds for the UK. 2 Indexes of my preference, but not limited to are the NAO and AO index, Currently the NAO has been pretty negative for the past few months, this is great if it pushes into Winter months. The AO is currently shifting between phases, however there is a sign it's going negative soon.
If both of these couple then it's a great start to Winter. The Arctic remains Blocked, with reoccurring Greenland Blocking( not everyone's favourite block) however I favour this for Northerly especially down the spine of the UK.
A Typical negative NAO patten would favour the above.
above Geopotential heights over the polar cap. I'll not include the chances of a SSW at this point, as it does not always equate to a great winter here in the UKWith. Eurasian snow cover Eurasian Snow cover is doing well as seen from Judah Cohen index.
outlook for Eurasian snow cover going into November looks good with cold uppers across large areas of Northern/Eastern Europe.
Of course as always I include "what's happening in the US", and no need to inform anyone the US/Canada is under the influence of cold Arctic Air currently. The current pattern is not " unusual" however, given its October it is rather a deep trough. An Alaskan Ridge is forcing a kink in the Jet stream allowing Bifurcation and Arctic air influx to the NW.
Picture is not current but gives the pattern here. Where there's a trough there's a Ridge, currently this is in the East, however with the PNA -Pacific North American Pattern due to switch phase to positive this Anomaly will push east in coming weeks, bringing cold to the eastern seaboard.
Given that scenario I would expect positive "Ridging " in the mid Atlantic, which effectively sets up North easterlies for the UK.
Of course the location of positive Geopotential heights here is critical, and dictates which side of the Jet stream we are placed. I would expect the High pressure to stay Northerly in the Atlantic at this point, which would be good for cold air influx down the spine of the UK. Currently we have decadal low sea ice not dissimilar to 2007, again my thinking "less sea ice- more open" warmer water convection. Convective snowfall bands often develop over open water and can carry heavy localised Snowsqualls. A similar set up hit Turkey in November 2004.
To finish, of course this is just my personal outlook with which many may disagree with, and with that I'm totally fine, however don't write winter off at this early stage. November- starts unsettle with Atlantic Influence, wet, however signs trending cooler mid month, a below avg CET.
December- Switching sides of the Jet stream with regular Arctic outbreaks, Omega is my favoured pattern here, heavier Snowfall confined to Northern UK, chance of snow past mid month further south as N/NE airflow brings cold uppers.
January..Blocked Greenland, North westerly influence, cooler than average with heavy frequent Snow fall. February - pattern changes to Scandi blocking with North easterly influence, very cold uppers and frequent Frost/ Snowfall. March - effects of a SSW could see widespread travel disruption via heavy Frosts lasting into mid day, snowfall localised to the East. Many thanks. David.
Looks promising at present