A wet and murky end to February

With no measurable sunshine and 8.2mm of rainfall the last day of February was in direct contrast to the previous three sunny days. However the thermometer did rise a little higher to 10.6C being 2.8C above the average.

At 23.15 there was a dramatic change in wind direction from south-southeast to north then northeast. As a result of this colder air arriving, a rapid drop in temperature was recorded of over 2.5C.

Tuesday arrived with a brisk northeasterly, not seen since January, and an air temperature of 6.5C. The northeasterly breeze is gusting quite strong due to the anticyclone now over eastern Europe rotating anticlockwise as they do and a depression in the eastern Atlantic rotating clockwise.

February 2022 Review

The first two weeks brought variable, mild weather. Every day saw the thermometer rise above the average with 13.2C on the 1st, which was 5.4C above the February average. However, there were several very cool nights with an air frost in the early hours of the 11th when the thermometer dropped to -1.2C

A very wide rain band, that at times stretched from the tip of Cornwall to Kent, produced 12.6mm of precipitation on the 13th with rain falling almost continuously from just before 10.00 till midnight. That was the wettest day since 30th October.

Storm Dudley arrived on the 16th driven by a powerful Jet Stream travelling at 200mph, hustling the depression across the Atlantic. The westerly wind gusted to 43mph with modest rainfall.

Much airtime on the 17th was given to advance notice of Storm Eunice that arrived on the 18th. This depression was flagged a ‘Red’ warning by the Metrological Office due to its intensity and extreme forecast wind gusts. A ‘Red’ warning is a rare event; the last was in November 2021 with Storm Arwen before that the ‘Beast from the East’ in March 2018. A strong Polar Vortex was created on the 17th as extremely cold air from Canada came up against moist air from around the Azores creating Storm Eunice that produced an exceptional temperature gradient. The Jet Stream, then running at 230 mph, whisked this depression across the Atlantic to the UK. Two meteorological phenomenon were created by this extreme storm. The first was a rapid deepening of barometric pressure, called ‘Explosive Cyclogenesis’, that saw the barometric pressure drop 22mb in just 12 hours. The second was a very unusual event called a ‘Sting Jet’, first identified by scientists in the UK after the Great Storm of 1987. A Sting Jet is a narrow band of very intense winds, difficult to predict, that can form in powerful weather systems. Such an event was identified on the 18th but fortunately developed over the sea area and not the UK.

Storm Eunice saw the wind rise rapidly in strength in Marlborough. Between 09.30 and 12.15 the wind gusted between 40 and 50 mph, producing a maximum gust of 56mph at 10.58 on the 18th. Very fortunately we were in the ‘Amber’ warning area, so did not suffer the full force of the storm or the exceptional rainfall seen further north. During a brief squall at 17.00, a heavy shower of ‘small’ hail was observed that temporarily gave a complete white covering that when melted produced 1.3mm of precipitation.

On the 21st Storm Franklin arrived making it the first time the Meteorological Office named three storms within a week. Storms only receive an official name when they are likely to cause a great deal of impact. They are determined by the National Severe Warnings Service, if for example they meet the Amber or Red warning storm category criteria. Storms are not named with letters starting with Q U X Y or Z as they are not common letters with which names begin. However, for safety reasons, storm names must be easily recognisable.

In the UK, The Met Office invites the public to send suggestions for future names through an online form. The Met Office received thousands of suggestions earlier this year, working with Met Eireann and the KNMMI, to choose some popular names and names that “reflect the diversity of Britain, Ireland and the Netherlands”. The Met Office issues a new list of names every September, a practice it started in 2015 with the launch of “Name Our Storms”.

During brief showers on the 24th, small hail, defined as being less than 5mm in size, was spotted briefly giving a covering before promptly melting.

The last week began to slowly calm down with winds moderating and minimal daily rainfall. Under high pressure sunshine hours increased to 5.8 hours on the 25th followed by the first air frost since the 11th with a low of -1.9C under clear night skies.

February was an unusually mild month with the mean temperature of 6.46C being 2.3C above the 38-year average. The February of 2002 was just a little warmer, but only by 0.09C! Analysing day and night extremes the figures show that the daytime average maximum was 2.9C above the average and the mean night-time minimum 1.6C above the average.

The coldest night of the month saw the thermometer drop to -1.9C in the early hours of the 26th. By contrast, the warmest day occurred on the 16th with a maximum of 13.4C being 5.6C above the 38-year average. There were only 5 nights when a frost occurred against the long-term average of 11.

In contrast to the very dry January the total rainfall for February amounted to 78.2mm being 117% of the 38-year average of +11.3mm. There were only 8 dry days during the month with 15 days classed as wet by the Meteorological Office being equal to a daily rainfall of 1mm or above when the long-term average is 11.

Brief hail showers were observed on the 18th at 17.00 and twice on the 24th at 11.47 and 12.28

Many reports of global warming refer to atmospheric temperature increases over a time period. However, very rarely is reference made to sea temperatures. Below are comments from a recent interesting report that I read.

The world’s oceans are hotter than ever recorded and their heat has increased each decade since the 1960s. This relentless increase is a primary indicator of human induced climate change

As oceans warm, their heat supercharges weather systems, creating more powerful storms and hurricanes also more intense rainfall. That threatens human lives and human livelihoods as well as marine life.

The oceans take up about 93% of the extra energy trapped by the increasing greenhouse gasses from human activities. Because water holds more heat than land does and the volumes involved are immense, the upper oceans are a primary memory of global warming.

The global mean surface temperature was the fifth or sixth warmest on record in 2021 (the record depends on the data set used).

There is a lot more natural variability in surface air temperatures than in ocean temperatures because of El Nino/La Nina and weather events. That natural variability on top of a warming ocean creates hot spots, sometimes called “marine heat waves,” that vary from year to year. Those hot spots have a profound influence on marine life, from tiny plankton to fish, marine animals and birds. Other hot spots are responsible for more activity in the atmosphere, such as hurricanes.

The scientists found that all oceans are warming, with the largest amounts of warming in the Atlantic Ocean and in the Southern Ocean surrounding Antarctica, which is a concern for the Antarctic ice as heat can creep under the ice shelves.

The warmer oceans also supply atmospheric rivers of moisture to land areas, increasing the risk of flooding.