Strong El Nino To Drive Warm Start To European Winter, Why Such A Warm November?

Thanks to the abnormally mild, humid, cloudy SW flow through the first 20 days of the month, it looks as though the UK has seen a top 5 warm November. Helped by the fact we experienced both the warmest day (22C) and night (16C) on record.

Warm, moist air with a lot of cloud cover means nights don’t get cold and even with the colder spell between 20-25th, this didn’t dent the warmth of this month.

Credit: Met Office

Credit: Met Office

Credit: Met Office

Credit: Met Office

Europe as a whole has likely experienced a top 5 warm November too.

Michael Ventrice

Michael Ventrice

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The powerful El Nino probably has a lot to do with this month warmth because the extremely warm central and eastern equatorial Pacific feeds an incredible amount of heat into the atmosphere and causes the typically much weaker sub-tropical high to be stronger and further north than it should be by now, hence a much sharper baroclinic gradient which equates to a stronger, further north subtropical jet. This not only pumps moisture but heat north into the mid-latitudes.

Credit: Tropical Tidbits

Credit: Tropical Tidbits

Note the warmer than normal tropical Atlantic with than warmer than normal extending up into the UK while there’s still that prominent cold pool over the north-central Atlantic.

Credit: Tropical Tidbits

Credit: Tropical Tidbits

Where those warmer-colder than normal waters meet, that’s often where the boundary is and where the jet and lows love to run along. So, this explains why we’ve not just seen a warmer than normal, wetter than normal November but also why the flow has been predominantly SW.

The GFS ensemble shows the strengthening of the polar vortex at 10hpa through the next 10 days, this if is correct, looks a milder, strongly Pacific/Atlantic dominated December reflective of a strong El Nino.

gfs_t10_nh_f00

gfs_t10_nh_f240

I’ve no reason to doubt a mild average to above average December but what’s very interesting is how the Canadian shows the big positive over Canada lifting northward in January with much weaker negative over the arctic and then a flip to blocking over top including Greenland come February. It’s worth pointing out that El Nino years are well known for being warm to start and cold during mid and late season. SSTA’s continue to warm north of the UK and Scandinavia as well as around Greenland. Look out Christmas onwards. I expect a more negative NAO/AO to develop.

Credit: Tropical Tidbits

Credit: Tropical Tidbits

Credit: Tropical Tidbits

Credit: Tropical Tidbits

Credit: Tropical Tidbits

Credit: Tropical Tidbits

Credit: Tropical Tidbits

Credit: Tropical Tidbits

Credit: Tropical Tidbits

Credit: Tropical Tidbits

Credit: Tropical Tidbits

Credit: Tropical Tidbits

Don’t write off winter!

See this morning’s video for the discussion.

More on the warm November with the below publication from the Met Office

Warm November on course to equal record in England

27112015

Early provisional statistics* (1- 25 November) show November has been notable for its mild weather.

Overall, temperatures for the UK have been 2.2°C above the November average, with this month on course in England to equal the previous warmest November in 1994 (9.5°C).

The other UK nations have been similarly warm

  • the mean temperature of 9.2°C in Wales currently the second warmest November on record here – behind 1996 (9.4°C)
  • the mean temperature of 6.6°C is currently joint third warmest in Scotland – behind 7.7°C in 2011 and 7.5°C in 1994
  • the mean temperature of 8.0°C in Northern Ireland is currently the fourth warmest on record – behind 8.8°C in 1994, 8.7°C in 2011 and 8.1°C in 2007

Apart from a short but marked cold spell on 21- 23 November there has been an absence of frosts in almost all areas, largely because of a humid, cloudy south-westerly airflow. This has also meant that most areas have seen very little sunshine. Most areas have had typical rainfall amounts for the time of year, but north-west Wales, north-west England and Southern Scotland have had well above average totals. There have also been a number of very windy episodes, including the impact of storms Abigail and Barney.

Of particular note was the temperature of 22.4°C recorded at Trawsgoed in Wales on 1 November and a remarkable overnight temperature of 16.1°C at Murlough in Northern Ireland on 21 November.

1-25 Nov mean temperature anomaly 1981-2010

 

 

 

 

 

 

 

 

Credit: Met Office

Credit: Met Office

Parts of southern and central Scotland, the Lake District, Pennines and Snowdonia have had over 150% of their whole-month rainfall average. North-east Scotland and parts of southern and eastern England have had slightly less than would be expected up to this point in the month. South-west Scotland has already had enough rain to make this the 5th wettest November for that region in a series since 1910.

Sunshine has been well below normal with just 33 hours of sunshine up to the 25th across the UK. This means November 2015 is heading toward being the dullest on records going back to 1929 – the dullest currently being 1962 with 39 hours.

1-25 Nov
2015*
Mean temp (°C ) Sunshine (hrs) Rainfall (mm)
Actual Diff from
81-10 avg
Actual % of
81-10 avg
Actual % of
81-10 avg
UK 8.4 2.2 33 58 136.4 113
England 9.5 2.6 34 53 93.3 106
Wales 9.2 2.4 33 58 197.4 122
Scotland 6.6 1.6 31 68 192.9 116
N Ireland 8 1.5 37 68 127.2 113

You can find out what the rest of the year has been like on our climate pages.

*Data from the Met Office’s UK digitised records dating back to 1910.

Please note that these provisional figures, especially for rainfall and sunshine, are subject to revision. Anomalies are expressed relative to the 1981-2010 averaging period.

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