Some of you eagle-eyed skywatchers will have noticed a ghostly glow in the sky on the way back from the pub in recent days. Was it real? Was it just an illusion caused by too much Gin? No, what you saw was real and is called ‘Noctilucence’. It is a spectacular display of very high clouds.
Noctilucence is exhibited by clouds that shine at night (Noctilucent means ‘night shining’ in Latin). Noctilucent Cloudsexist in the upper atmosphere (Mesosphere), at a height of around 50 miles. They are composed of ice crystals and can only be seen in astronomical twilight. That means they are best seen in the summer months, but they are too faint to be seen in daylight. They require moisture, dust and very cold temperatures (less than -120 degC) to form. The Mesosphere is at it’s coldest in the summer months, so favours their formation.
The clouds shine on summer nights when the sun is below the horizon at ground level, whilst up at 50 miles the noctilucent clouds are still in the sunlight. The whispy clouds seem to glow in this ghostly manner. They are a comparatively recent discovery and are not fully understood, but they seem to be occurring more often and with increasing brightness.
There have been some fantastic photos posted on the internet in the last week or so, but the best I have seen relevant to us is from Mike Ridley who took this superb composite photo over Durham City from Whinney Hill on 17th/18th June 2019.
The report above appeared in the Northern Echo newspaper on 29th May 2019.
The axis of funnel clouds may be vertical, inclined (as seen here), or sometimes long and sinuous. In the UK it is usually tens of metres in diamater (not huge). It is much rarer for funnel clouds to touch the ground and that is when they become tornadoes, but it does happen occasionally. Most UK tornado reports come from The Midlands, Central, Southern and South East England and East Anglia. Our very own Tornado Alley!
If you see a funnel cloud or suspected tornado, you should report it to TORRO (Tornado and Storm Research Organisation). They catalog such stuff and produce stats and mapping.
There are 40 tornadoes per year recorded on average in the UK. England has the highest reported incidence of tornadoes per square mile in the World. That usually surprises a few people, but it’s true!
The longest ground track by a tornado in the UK was in May 1950, when a tornado traveled 107km from Buckinghamshire to Cambridgeshire.
“Southern Ireland was battered by gales, but the strange weather that hit the british mainland was unlike anything i’ve ever experienced. At 2pm in the afternoon, the sky had a strange orange hue, and it was dark – REALLY dark. The streetlights were on and cars were driving with full headlights. It was almost completely still, but a smoky smell hung in the air. This was afterwards attributed to a combination of forest fires over the Iberian Peninsula and Saharan dust, all dragged North on the Eastern side of the depression centre. Within 90 minutes the sun was out and it was a different world.” – Dave O’Hara
A bright red sun glows in the sky over Durham, October 16 2017. It was the 30th anniversary of the Great Storm of 1987. The sun had an eerie red cast because southerly winds ahead of an ex-hurricane Ophelia had drawn air all the way from the Iberian peninsula, where forest fires had been raging.
The photo above was taken in Gilesgate in mid-afternoon, but it was so dark that street lights came on automatically and drivers had to use their headlights to see. There was a strong smell of burning in the air. All birds had fallen silent, believing night was upon them.
A satellite picture clearly shows the red dust and smoke embedded into the weather front approaching the UK.
The month had 3 new daily records in the Central England Temperature record. 17.2, 16.4 and 14.9C on the 14th, 16th and 25th respectively. The maximum temperature at Gilesgate was 19.8 degC on the 13th of the month, with the minimum of 2.8 degC on the morning of 30th resulting in the first ‘car windscreen scrape’ of the Autumn.
A fantastic display of nacreous (mother of pearl) clouds occured across NE England in February 2016. These photos were taken above Durham Cathedral and Castle at about 7:15am.
Nacreous Clouds are quite rare. They can glow very brightly due to iridescence and are much higher than other tropospheric clouds, a height of 15-30km above the ground is typical. They are caused by wave-like motion of air, normally due to the proximity of mountain ranges. Best viewing is just before dawn and just after sunset.
This incredible Shelf Cloud, looking like an alien spacecraft from the film “Independence Day” came in over Durham in July 2015. Although it looked very threatening, on this occasion not much rain fell from it. It’s the best example I’ve seen of a Shelf Cloud in the UK.
On 1st July 2015, the temperature hit 30 degC in Durham, being only the 30th such occasion since 1850 to reach the mark. The actual max was 30.2 degC. It was a very hot sultry day, which quickly degenerated into thunderstorms with rain and hail.
A shelf cloud is a low, horizontal wedge-shaped cloud, associated with a thunderstorm gust front (or occasionally with a cold front, even in the absence of thunderstorms). A rising cloud motion often can be seen in the leading part of the shelf cloud, while the underside often appears turbulent, boiling, and wind-torn.
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