Europe Winter 2017-18: ‘Relatively mild’ Dec-Jan, Potentially ‘very cold’ late Feb, March!

Written by on February 19, 2018 in Rest of Europe, United Kingdom & Ireland, Winter 2017/18 with 0 Comments

December and January turned out average to warmer than normal across Europe and the UK ‘overall’ but certainly this big picture doesn’t tell the whole story as there have been frequent colder periods ‘locally’.

January anomaly

Credit: Mike Ventrice

However, the large-scale trend shifted firmly to colder in February.

Credit: Mike Ventrice

Despite a warmer than normal Dec-Jan period, there have been spells of significant winter weather but the mild in between allowed the month’s to average out normal to above normal.

For Scotland it was a slightly milder than normal December but following a 2nd cold November in a row, December’s 1st half was coldest since 2010 but a 10 day stretch between 15-25 Dec of mild followed by cold Christmas to New Year week meant the month ‘averaged normal to slightly above’.

January was mild for the UK overall. A warmer than normal England and Wales but colder than normal Scotland meant mild outweighed the cold and so again, like December, despite some significant cold, January was still mild when taking the whole UK into account.

A frequently negative Arctic oscillation but positive North Atlantic oscillation meant a constant ‘westerly’ but with plenty of cold air entrainment. The cold focused mainly over Scotland where precip often fell as snow even at low levels but slightly milder air for England and Wales, hence a normal to slightly above normal January for England and Wales but colder than normal Scotland.

The first half of Feb has seen much colder influence across a larger area despite the continuation of a positive North Atlantic oscillation and dominant Icelandic low. The negative Arctic oscillation has been why it’s been a pretty cool winter despite the westerlies dominating.

Now that we’ve seen a major sudden stratospheric warming, I recon we’ve a wild end game to winter. Pretty much all the modelling now agree on a dominant easterly flow late Feb through a good chunk of March. Snow and persistent frosts are expected along with a biting easterly. The question is how severe?

The last occurrence of an SSW was January 2013 and this led to a cold February and even colder March. March 2013 turned out to be the UK’s coldest in 50 years. We may well see a repeat next month.

When all’s said and done… like the cold or hate it, we should all be ready for spring warmth.

AO, NAO is tanking!

When that happens is the Arctic dramatically warms up. Remember we saw a near 70C rise in temperature within 3 days at 10hpa over the Arctic and now that response is reaching the troposphere now 6-10 days after the initial up in the stratosphere. We here in the middle latitudes wait another 5 days and eventually all this cold rushes here.

CFSv2 weeklies show the build-up of positive heights over the arctic and Greenland as the upper winds reverse.

Credit: Tropical Tidbits

Credit: Tropical Tidbits

Credit: Tropical Tidbits

2m temp anomaly

Credit: Tropical Tidbits

Credit: Tropical Tidbits

Credit: Tropical Tidbits

Some of the latest tweets regarding the recent SSW.


Tags: , , ,

Follow us

Connect with Mark Vogan on social media to get notified about new posts and for the latest weather updates.

Subscribe via RSS Feed Connect on YouTube

Leave a Reply