THE STORM OF MARCH 4, 1818

Early March often brings stormy weather, a singularity that has a probability of 88 per cent!

An example of just how long this singularity has been around can be found in the early 19th century

In his book The Climate of London Luke Howard mentions that the air pressure on March 4th was the lowest measured for some 37 years. The lowest point of 28.35 inches (960mb) is remarkable in that the lowest I’ve measured in Wanstead since 2012 was 969.8mb last December!

The storm brought devastation across a wide swath of southern England with loss of life on both land and sea.
Howard’s account of the storm mentions the barometer falling an inch in 15 hours with rain after dark with the wind “raging in violent gusts from SE and SW till past midnight when it abated after much thunder and lightning”.

His friend in Manchester, Dr William Henry, wrote a storm SW caused considerable damage, delaying the London mail in Macclesfield from 8pm until 3am on the 5th, the storm raging until 3am. The barometer fell to 28.2in (955mb) at Manchester.

Character of the period for the most part tempestuous with frequent rains the barometer running through a series of sharp depressions till near the close when it suddenly assumed the elevation of fair weather Almost all the showers from the first were more or less mingled with hail

Elsewhere in Britain public ledgers also reported the storm.

Yarmouth A most tremendous gale of wind from the S to the SE with rain came on about 8pm which continued with increasing violence all night and has done considerable damage to the shipping on this part of our coast.

Deal Last night it came on to blow a most tremendous gale from the south and continued nearly the whole of the night with unabated violence at midnight it blew a complete hurricane accompanied with thunder and lightning during which several vessels in docks suffered.

Portsmouth It blew a tremendous hurricane last night from S and SSE accompanied with the highest spring rides ever remembered.

Ryde One of the severest gales of wind that has been felt here for the last 37 years was experienced last night. It commenced about 4.30pm and continued with increased violence until past 11pm during which time the greater part of the pier and several houses were demolished. The supposed damage is estimated at between £4,000 and £5,000. No lives were lost nor any damage done to the shipping.

Dartmouth We experienced a perfect hurricane last night at SSE from 6pm to 10pm

Exmouth On the 4th instant between 7pm and 8pm we had a most tremendous gale of wind about SSE with dreadful rain thunder and lightning.

Falmouth At day light this morning the wind was from the WSW moderate. About 11am it strengthened to the S and from that to SSE and since that time until 10pm it has blown a hurricane with a heavy sea.

Penzance We had a very heavy gale here on Wednesday the 4th.

Milford On the 4th it blew a very heavy storm from SW to WNW.

Leicester Wednesday night was one of the most boisterous recollected for years past. Much damage has been sustained in this town and many parts of the county.

Hull At high water about 4.30pm the wind then blowing from the SW with moderate weather the tide flowed at the Old Dock Gates 18ft 6in. After the tide had fallen from 1 to 2in the dock gates closed as usual with the ebbing of the tide which then began again to flow to the height as near as can be calculated of four or five inches thereby opening the gates again and continued flowing. The tempestuous night of Wednesday ensued the wind blew a heavy gale still from the SW and at high water at 5am Thursday morning the tide was 14ft 1in being 4 feet 5 inches less than on the preceding evening although from the spring tides having put in the water ought according to the usual state of things to have flowed higher than on the Wednesday evening

Plymouth At the commencement of the winter a few large stones were placed by themselves on the top or finished part of the Breakwater to see if they would stand the winter gales they stood all but this last and this morning I found them washed from the top and lying on the North Slope There were three of them one of nine tons and the other two of five tons each they will be replaced as soon as possible for further trial Plymouth The effects of the late thunder storm of the 4th March on a fir tree belonging to W Langmead Esq at Elfordleigh in the neighbourhood of Plymouth are too singular to be omitted and perhaps the most extraordinary ones that ever occurred in this county on such an occasion The tree in question has been long admired for its size and noble proportions being more than 100 feet high and nearly 14 feet in girth but it exists no longer having been literally shivered to pieces by the electric fluid Some of the fragments lie 260 feet from the spot and others bestrew the ground in every direction presenting altogether a scene of desolated vegetation easier to be conceived than described.

The cold spell of February 2021

Valentines Day 2021 saw the cold spell come to an end in the London area. Maxima over the past 7 days never exceeded 2.3C on any day, the yardstick I use for a spell of cold weather to qualify.

Though some places did get a decent amount of snow precipitation in this area was very low ; lying snow at 9am at this station never exceeded 3cm. Very cold, dry air however was enough to preserve cover out of the sun.

As cold spells go it was two days longer than the median of 5 days, so slighter colder and drier but with double the amount of sunshine.

A couple of years ago I tried to rank cold spells in this area since 1960, with mixed results. I’ve since revisited the method and have achieved better results using the following algorithm.
(Number of days * total precipitation)*(mean temperature of spell)-(total sun hours). This gave the following list.

And the next 26 cold spells

A comparison of the upper air at the start of two cold spells

There’s been many images that define this spell but this post probably nails it in that I’ve never seen the ice thick enough on the marshes to tempt someone to ice skate.

The GFS Scottish Christmas Day blizzard of 2020

With the midnight run of this model bringing the start of the 25th into range the prognosis for the big day is a rare white one – for those north of the border.

The rest of the country is messy mix of sleet and, in London’s case, cold rain with a high of 7C. It looks fairly average for this locality!

The GFS operational chart for 0000 on the 25th

But followers of this blog and elsewhere will know that any model output beyond 72 hours should be taken with a very large pinch of salt.

But while conditions out to 15 days are often very different they can give a general guide to how the atmosphere is evolving in the medium range. The last few winters I’ve been doing this Christmas day model blog have revealed that conditions are sometimes not wildly different from what was hinted at 372 hours before.

Over the last few days the GFS, and other models, has been flip-flopping between cold and mild, a symptom of the current atmospheric situation which suggests that the polar vortex may undergo displacement as we progress further into winter. This could signal colder weather for NW Europe – but exactly where this colder weather will be as we progress to the end of the month is very uncertain – any colder than average weather could remain closer toward Central Europe, as happened in 2008.

Below are charts for each day from the midnight operational run of the GFS model.

London winter forecast 2020/21

The best chance for lying snow this winter looks like being at the end of the second week of January.

A combination of local analogues and global atmospheric factors including the El Niño-Southern Oscillation suggest that the coming season will be colder than recent years. Though that’s not saying much considering just how mild winters of the past decade have been.

Meteorological autumn was the warmest for 5 years and slightly drier than last year’s wet autumn. Though it shares some similarities with 2015 the external influences are thankfully different to that season which produced the warmest December on record. Considering data back to 1797 I was able to make the following suggestions on how the next 90 days may unfold.

December is most likely to be around average temperature-wise with rainfall also about average. Possibly stormy at the end of the first week. Any snowfall events are likely to be marginal – bad news for anywhere below 70m above sea level. In terms of Christmas a white one in London looks unlikely. There may be interest in the week running up to the big day but I wouldn’t be surprised to see that inexplicable warm up that often happens just as the 25th arrives.
Mean: 5.8°C (5.6°C 1981-2010 average)
Rainfall: 57.1mm (53.2mm 1981-2010 average)

January is the month most likely to see any lying snowfall, particularly during the first half of the month, with the mean temperature about 1C colder than average. Rainfall is likely to be above average.
Mean: 4.1°C (5.2°C 1981-2010 average)
Rainfall: 63.8mm (53.2mm 1981-2010 average)

February looks wet and mild overall.
Mean: 6°C (5.3°C 1981-2010 average)
Rainfall: 55.6mm (39.2mm 1981-2010 average)

Overall the mean for winter: 5.3°C, a little below average.
And rainfall about 120 per cent higher than average.

Looking in closer detail reveals that the coldest period is most likely to be between 13th and 19th January, with anomalies sufficiently low enough for lasting lying snow.

The extremes that no-one can forecast

As well as the extreme December 2015 the analogues also revealed the severe season of 1822-23 which saw ice on the Thames by late December. February 8th saw a great snowstorm in northern England where people had to tunnel through the snow.

Another was 1950-51 which was very snowy at high levels. There were 102 days of lying snow at Dalwhinnie (1000ft), exceeding the 83 days set in 1946-47. December 15th saw 15in of snow in Shanklin, Isle of Wight in 3.5 hours.

Hours of frost

Frost is a rare beast this year, even in the Wanstead Park frost hollow.

So far this year I’ve recorded just 82.5 hours where temperatures at 4ft (1.2m) were -0.1C or below. That’s just 37 per cent of what is recorded in an average year. And would suggest that frosts in December will be above average.

The lack of frost this year is even more remarkable given that the past seven years, especially the winters, have been so mild.

A closer look at the data shows that winter months are no guarantee of seeing temperatures fall below freezing. The record mild December 2015 and February 2014 are testament to that.

The fact that January 2017 looks the most remarkable month for frost reveals just how mild recent years have been.

Cathedrals of snow

Snow is ever present in the UK in most years though you have to look hard to find it in high summer.

A dedicated group of enthusiasts, led by Iain Cameron, chart and catalogue these snow patches – many of which are hidden or only seen as distant white dots during Scottish Highland walks.

Responding to an appeal in September I met up with Iain and other volunteers to chart the patches in Observatory Gully on Ben Nevis, the UK’s tallest mountain.

Our route up in the shadow of the magnificent north face of the Ben was a warm one; to our left a procession of ant-like figures were tracking the CMD arrete route to the summit, walkers making the most of the amazing weather.

The North Face path up to the Ben was easy to follow under clear blue skies. My previous visits to the fogged-in summit required map and compass.

Out of the sunshine it was noticeably colder in Observatory Gully; being north facing it sees very little of the sun even in mid June, slowing down the rate of melt of the snow which can be tens of feet thick by the end of the snowfall season. Being encased in snow for so long obviously has a chilling effect on the rock.

The walk up on the scree was hard work and I was surprised to see so many debris including parts of large parts of old galvanised chimney cowls, the legacy of the observatory that once sat proudly on top of the Ben. Not many people trek this way, being a bit of a cul-de-sac. To reach the 1,345m summit from here requires a 200m climb at the end.

As we edged higher the dot of snow grew ever larger and is surprisingly big by the time we reached it, Iain was surprised how hard the snow was. From Iain’s reports, published in the Royal Meteorological Society’s Weather magazine, I’d been fascinated by the images of the patches with naturally carved tunnels underneath them; the light inside the ‘cave’ has a gorgeous blue hue to it.

The light inside the snow patch has a gorgeous blue hue to it. It is understandable why so many are drawn to these ‘cathedrals of snow’.

It was at this moment that I realised that this was a large part of the draw of tracking these patches; a fascination with snow in an area where the odds of it existing all year round seem to be forever diminishing.

At the start of Observatory Gully the snow patch is a tiny dot.
On closer inspection the snow patch is a few dozen feet across and is far bigger than it looks from the valley.

Seasons of melt and snowfall

Snow has only vanished entirely in Scotland six times. Three of these occasions were in 2003, 2006 and 2017.

Mean temperature statistics from Cairngorm Summit show just how much the seasons can vary. Of course mean temperature is just one variable that affects snow survival rates. For example the Western Highlands saw huge amounts of snow fall in February and March above 300m, a factor that would have helped snow survive. Though the most recent melt season was 0.4C cooler than 2019 there was probably a far greater volume of snow.

* Because of the unreliable nature of mountain-top records the Met Office data for Cairngorm Summit has some large gaps, it is only the last 5 years that have complete records . I discounted any years that were missing more than 5% of data.

Record rainfall in October 2020

The wettest October since at least 1797 was recorded last month with some 159.2mm collected, 238 per cent of average.

The month started wet with the daily October rainfall record also broken with 49.1mm on the 2nd, the wettest day ever recorded in the UK.

With all that rain sunshine was at a premium; the 51.6hrs recorded was the second lowest October total since 1881. Only 1894 was duller.

The monthly mean was 11.7C, 0.1C below average.

Does any of the above have any bearing on what we can expect this winter? Possibly, but there are so many variables to consider.

Looking at rainfall patterns alone would suggest mean temperatures in November being a degree cooler than average and December broadly average.

Rainfall in November average while December is slightly below.

Make your own grass minimum thermometer

Traditional grass minimum thermometers are expensive. And delicate. Over the years I’ve lost a few of these spirit-filled devices thanks to curious foxes and other wildlife.

But using a £20 datalogger off eBay – units that are used for cold chain supply – and junk found in the garden I’ve found a solution.

As well as the logger and probe you’ll need:
Access to a PC
An old pickle jar with lid, preferably with a wide neck.
1.6m garden cane, cut into 8x 20cm lengths.
Thin garden wire.

list

Once you decide where to place the device (a part of lawn with limited traffic) dig a hole deep enough so just the very top is exposed.

Drill a small hole (big enough for the wire to pass through and the probe to fit snugly) into the top 2cm of each cane before carefully hammering each length into the surrounding turf, leaving 10cm exposed. The last length- that will host the probe – should go in the centre.

Drill a small hole in the lid that is just big enough for the probe to pass through.

You are now ready to place the datalogger into the jar to start recording.

done

First you’ll need to set up the device on your PC. Programs to do this are available to download.

The devices can hold up to 16,000 records. I set mine to 1 minute intervals, allowing for a continuous 11 days of records.

The enclosure is more to stop any foot traffic kicking over and damaging the probe. If wildlife proves to be a problem there is an option of running a very-wide gauge grill over the top.

Two warm April days 128 years apart

The synoptic pattern on Sunday, April 5th, was very similar to the pattern on Tuesday, April 5th 1892.

With so few planes in the sky because of the coronavirus lockdown it offered an ideal opportunity to compare temperatures and sunshine totals between now and then.

Sunday dawned sunny and clear and stayed that way until dusk, some 11 hours of sunshine recorded, exactly the same as 1892!

The temperature in Wanstead reached 22.3C, 0.9C cooler than what was recorded at the Royal Observatory, Greenwich, in 1892. This maximum was reached after an overnight minima of 5.3C, the same as the 41.5F recorded at Greenwich all those years ago.

Looking further afield, and at the spell over 3 days… markmpcc

4th

5thww

6th

 

 

 

 

London’s colder than average months

Last November was on the cold side prompting me to investigate whether we were about to record a third month in a row below average. December turned out to be mild and wet, the lack of snow especially stark in Scotland.

The findings of that study showed that any sustained period of colder than average months was more likely to happen during months of March, April and May, nothing unusual there, especially considering H.H Lamb’s weather types.

I decided to scrutinise further all the colder than average months in this area, considering the 1981-2010 average, back to 1981. This gave the below results.

neg anoms

The dataset covers 399 months, of which 200 were colder than average.

The overall picture shows that negative anomalies are becoming more and more rare, though with notable exceptions being March 2013, December 2010 and January 2010.

The only month that has showed any sort of consistent general decrease in negative anomaly is November.

*For good snowfall at this station needs a negative anomaly of 2C during the months of November, December, January and February.

Meteorology-based musings about east London and beyond

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