King Winter: November 1919 remembered

Introduction

100 years ago in November 1919, the United Kingdom was in the middle of a severe cold spell. This was a cold spell that would be significant enough in the heart of winter, but the fact it took place in mid-November is extraordinary. Across the whole of the British Isles, from Scotland in the North, Ireland in the West to the most Southerly point on the Isle of Wight, there was thick snow.

The month as a whole was on the “well below average” side in terms of temperatures, with it easily being the coldest November on record for the UK temperature series back to 1910, and the joint 7th coldest November on record for the Central England Temperature (CET) series that goes all the way back to January 1659!

Autumn 1919

The autumn of 1919 was a strange and exceptional season in the UK. It wasn’t just November that was unusually cold either.

On the 26th of April 1919, an Arctic airflow plunged southwards over the UK, which was followed by even colder air, driving southwards as a low moved southwards down the North Sea on the 27th. A tremendous wet snowstorm developed as rain turned to snow inland as the precipitation became slow moving across the southeast of England. Depths of snow in the Home Counties to the north of London approached 40cm. As per usual, there was chaos in transport and telecommunications.

By Weather-history

Gatton Bottom, Merstham snow photos

September and October were both cold too although the season didn’t start off that way. The second week of September featured a mini heatwave, including a maximum temperature of 32.2℃ at Raunds on the 11th, which would become one of the latest dates to achieve 90°F in the UK on record, and was also the hottest day of 1919 following a cool summer.

There was a notable shift in wind direction on the 12th September with a 15-20 degree drop in temperature for some from the 11th into the 12th. For example, Nottingham reached 29.4℃ on the 11th but only 13.9℃ on the 12th. However, the weather continued dry and fine, despite the cooler days, before an exceptionally cold (for September) northerly developed over the UK on the 19th/20th. This northerly would bring snow cover to low ground in northern England, on higher ground in Wales, and in southwest England and the Midlands. The snow was up to 2 inches deep at Princetown in Dartmoor and snow cover lasted on Snowdon for a week.

October had a CET of only 7.4℃, which made it the second coldest of the 20th century, and featured a notable prolonged frosty spell, but it was also dry and very sunny. Overall, it was the coldest autumn of the 20th century, just ahead of Autumn 1952. No surprise there, is it?

Running through the month

Continuing the exceptional cold autumn of 1919, November began with an easterly airflow as high pressure centred just to the north of Scotland. Days were relatively chilly in terms of temperature itself, but there would have been quite the windchill added on, especially in easterly gales and on the cloudy side generally.

There was a “gale of exceptional violence” (UK Met Office, 1919) in the Straits of Dover on the night of the 1st/2nd and three vessels were lost on the Goodwin Sands. A sub 980mb low developed over the Azores on the 5th and pushed towards the UK by the 7th but filled as it failed to make progress northwards through the country and was forced southeastward into France. A depression formed over the North Sea on the 8th which resulted in a lot of rain and sleet in Scotland although this would turn readily to snow. Easterly winds got stronger at the same time to the north of the UK.

GOODWIN SANDS DISASTERS
MANY LIVES LOST.
HISTORIC GRAVEYARD OF SHIPS.
LONDON, Sunday, – Four small vessels were wrecked on the Goodwin Sands in a violent gale on Saturday night. The Deal lifeboatmen saw a wave wash away six people who were clinging to rigging. All perished. The lifeboat picked up two sailors, who were clinging to an upturned boat.
The lifeboat was again called out and rescued two men who were clinging to a wreck. They saw another wreck, in which case all the crew perished.
A steamer picked up a boatload of survivors off Deal.

[Goodwin Sands are famous sandbanks stretching 10 miles N.E. and S.W. at an average distance of 5½ miles from the east side of Kent. Large level patches of sand are left dry when the tide recedes, and afford a firm foothold, so that cricket has often been played upon them. When covered the sands are shifting and may be moved by the prevailing tide to such an extent as to considerably change the form of the shoal ; till the general outline has been fairly constant. These sands, which are marked by four light ships, have always been dangerous to vessels passing through the Strait of Dover. They serve as a breakwater to form a secure anchorage in the Downs when E. or S.E. winds are blowing: but when the wind blows strongly offshore, ships are apt to drag their anchors and drift onto the perfidious Goodwins. Many wrecks have taken place there, the most terrible being the loss of an entire fleet of 13 men-of-war during the great storm on the night of November 26, 1703.]

On the 11th, a secondary low passed across Scotland and was accompanied by snow, hail and thunderstorms in the northeast of England.

Winds calmed down which allowed frosts of unusual intensity, but the cold airmass was fairly unstable, so further snow showers continued, even after the widespread snowstorm on the night of the 11th/12th.

After the first Armistice Day commemoration on 11th November which was bitterly cold, snow showers fell over many parts of the country. The next day, snow lay 8 inches deep in Edinburgh, with many villages in Scotland cut off.

Scotland got below -20℃ on both the 14th and 15th, smashing previous November records, and still stand to this day including the record low of -23.3℃ at Braemar. This was the joint lowest temperature in the UK for any month since February 1895 and we would have to wait until February 1955 to see a lower temperature than it for the 20th century. One also has to skip forward to 30th November (1985) for the next -20℃ daily record after the 15th. Just shows what is possible in the UK in mid-November given the right pattern or circulation.

By 14th November, parts of Scotland and North Yorkshire were up to 5 feet deep in snow.

It turned much milder for a time from the 17th to the 20th as the westerly winds became re-established with low pressure developing over Iceland including a sub 970mb low on the 17th. Secondary lows associated with this deep depression passed over the UK and brought much rain. However, this was a temporary milder period.

By the 20th, low pressure dived down the North Sea allowing a northerly tilt to the wind. This brought cold weather again and snow, hail and sleet showers were frequent in most localities until the 23rd before another mild push. The 23rd was generally the mildest day of November.

On the 24th, a deep depression moved eastwards from Iceland and a secondary to this system moved very rapidly east across the UK, increasing the wind to gale force widely with squall lines to the north. During the 26th to 28th, a belt of low pressure covered the UK and showers of sleet or hail, and even sometimes thunderstorms locally, were common.

On the 29th, a low pressure system developed to the south of Ireland which moved eastwards to southern England and increased in intensity, causing snow in the Midlands. After a very cold night, the last day of November 1919 was rainy and mild, appropriately leading into the mild and wet winter of 1919/20.

Synoptic pattern

November was dominated by an unusual pattern of high pressure in the North Atlantic and ridging into Greenland with low pressure centred around the southeast of England and the Low Countries. This meant the mean wind direction was northeasterly drawing cold polar airmasses from Scandinavia. This was an example of the negative phase of the North Atlantic Oscillation (NAO).

In a typical November, low pressure is centred around Iceland with high pressure around the Azores and ridging into mainland Europe driving the zonal flow where the wind direction is westerly. This is what you associate with the positive phase of the NAO.

With many thanks to Sryan Bruen for the article content. You can follow him on Twitter and visit his website below.