Tag Archives: wanstead

London’s March extremes since 1959

February 28, 2018 wansteadmeteo 5 Comments

I’ve put together a few top 10s of stats for Wanstead, St James’s Park and Heathrow for the month of March.

The month, the first of the meteorological spring can offer really contrasting weather; perishing cold and very pleasant warmth are both very possible, as the values show.

Probably most notable in the list is the cold March of 1962 which was the coldest of the 20th century and 11th coldest in a local list going back to 1797. March 2013 was also very cold. Strong winds from deep depressions often feature as does the odd blizzard.

Marches in the 1960s also appear to often start very cold and end very warm; the term ‘In like a lion, out like a lamb’ being very appropriate.
•Though this blog only covers extremes back to 1959, thanks to Met Office digitised data, I’ve unearthed records prior to this. Both W.A.L Marshall’s A Century of London Weather (covering 1841 to 1941) and J. H. Brazell’s London Weather (covering 1841 to 1964) confirm the coldest March day as the 13th in 1845 when 25F (-3.9C) was recorded at Greenwich.

The coldest March minimum was 4/5 in 1909 with 9F (-12.8C) at Epsom. Greenwich and Hampstead recorded 14F (-10C)

Some national UK March values according to TORRO

Hottest: 25C Wakefield, West Yorks – 29th 1929
Coldest: -22.8C Logie Coldstone, Grampian – 14th 1958
Wettest: 164.3mm Glen Etive, Highland – 26th 1968

Blizzards, cold spell, London snowfall, London weather, UK snowfall, Weather, weather pattern

The most potent cold spells since 1960

February 21, 2018 wansteadmeteo 4 Comments

‘This cold spell is rubbish compared to what we used to get!’
Every winter when weather model hype builds expectation for many, often days in advance, the outcome never seems to quite match the hype.

This expectation among weather nerds is inflated even further when the tabloids cotton on and build anticipation further only for it all to end in a ‘damp squib’.

I’ve lost count of the number of times when excited enthusiasts proclaim that an incoming cold spell is going to last at least three weeks; the reality being that the intensity of the cold has gone after four or five days. Cold spells since 2008 often arrive as a ‘blob of cold air’ from the continent that eventually gets ‘warmed out’; it’s been a very long time since we had a cold spell that’s been fuelled by a continual feed of air off the continent.

Screen Shot 2018-02-22 at 09.02.23 — In 2018 the really cold air aloft had warmed after 5 days

To illustrate my point I had a look back at every cold spell in this area of suburban east London since 1960. I weeded out the feeble efforts of the last few years by only considering spells where the maximum didn’t exceed 2.8C. The results spanned from the most recent very localised cold spell of December 2022 to the mammoth 31-day Siberian blast that began on Boxing Day 1962.

In another blog I remarked how similar the 2018 pattern was to February 1962. This cold spell began on the 26th and lasted 9 days. Some 7cm of snow fell, this drifting in the wind, possibly making it seem worse with only 4 hours of sunshine which would have maintained any snow cover.

One of the snowiest cold spells happened in February 2009, eight days after an SSW event that lead to a polar vortex split. This four day spell saw a total of 26cm of snow fall.

February 1991 was even snowier, the intense cold lasting some 11 days.

Looking at other February cold spells a 7-day spell occurred in 1985 about a month after an SSW event.

Overall the median length was 5 days with an average of 6cm of snow and 8hrs of sunshine.

*A survey of winters ranked for temperature and snow can be found here.

London snowfall, London weather, Sudden stratospheric warming, UK snowfall, Weather, weather pattern

The cold spell of February / March 1962

February 16, 2018 wansteadmeteo 3 Comments

The last week or so has been agony for model watching coldies wishing for a snowy end to winter.

27021962 — The Synoptic chart for February 27th which saw 4 inches of snow in Stratford, east London

Solutions have often flip-flopped between a mild and cold outlook. Even this morning at 6 days out the GFS and ECM model temperature outcomes differed by some 20C, a choice between spring and deepest winter!

Sometimes you have to try and second guess what is going to happen by looking at previous patterns from years past.

Yesterday at Philip Eden‘s funeral I spoke to Woodford Green resident Ron Button. He pointed out how much this February reminded him of February 1962, a month that was non-descript for the first three weeks before turning very cold and snowy. Ron, who has kept a meticulous record of the weather ever since his interest was prompted by the severe winter of 1947, produced diaries of 1962 when he was living in Stratford. The entry for 26th / 27th read: “4 inches of snow with drifting”!

The March that followed was the coldest of the 20th century, ranking 10th in my list back to 1797, and 0.3C colder than March 2013. The fact that the monthly sunshine in 1962 was only slightly below average is testament to how cold the source of the air must have been. March 2013 was very dull by comparison!

An entry in London-weather.eu reads that March was colder than any of the previous 3 winter months: “The first three weeks were mostly mild and dry. It was often breezy which resulted in fewer than average night frosts. Frontal systems off the Atlantic passed through the London area, most of them weak though on the 12th, nearly 8mm of rain fell with southwesterly winds gusting to 57 knots. During the last week of the month, it became much colder, and on the 26th snow fell with the temperature not rising above -0.3C all day.”

There was no stratospheric sudden warming that winter and ENSO was neutral.

The winter of 1961/62 ranks only 14th in my list of worst winters, mostly because the core of the cold happened in March which is considered spring in meteorological circles

The Snow Survey of Great Britain also makes interesting reading with these entries for February and March.

Wanstead Park history, Weather

A new weather station for Wanstead

February 13, 2018 wansteadmeteo Leave a comment

Wanstead has a new automatic weather station to complement the one set up in November 2012.

The new AWS, situated in the grounds of Wanstead Golf Club, comes thanks to Friends of Wanstead Parklands. Data from the unit, which is sited very close to where Wanstead House once stood, will be used to help monitor the levels of the park’s lakes.

The sensor unit, 750m NNE of the weather station wansteadweather.co.uk on the Aldersbrook estate, is much better exposed and will hopefully offer more accurate wind and sunshine readings. It will also provide a chance to further investigate the area’s microclimate.

The station has already shown that the golf course is warmer on a radiative cooling night than the Aldersbrook Estate.

The AWS can be found at WeatherCloud https://app.weathercloud.net/d0507444306#profile

Also at Weather Online
https://www.wunderground.com/personal-weather-station/dashboard?ID=ILONDON737

It also tweets hourly and provides an automatic 24hr daily summary. You can follow it @WansteadParkWX

Hourly tweets and all things weather continue as normal at @wanstead_meteo

London weather, Weather

London’s February extremes since 1959

February 4, 2018 wansteadmeteo 5 Comments

I’ve put together a few top 10s of stats for Wanstead, St James’s Park and Heathrow for the month of February.

Probably most notable is the cold February of 1991 which saw the deepest snowfall I can remember – days of snow saw the level depth past my knee in suburban London. February 1986 was also very cold but also very dry with little snow.

Februaries in the 1990s were also often warm with 19.7C being reached in Wanstead on 13th in 1998.

It is a shame that the Met Office only publishes easy to access daily data in Excel format back to 1959 as this obviously omits the classic snowy February of 1947 which is worth a blog on its own.

My winter forecast for the London area can be found here.

Some national UK February values according to TORRO

Hottest: 21.2C Kew Gardens – 26th 2019
Coldest: -27.2C Braemar – 11th 1895
Wettest: 196.6mm Ben Nevis, Highland – 6th 1894

Forecast, UK snowfall, Weather, weather pattern

A 100% guaranteed snow risk for rest of winter

January 14, 2018 wansteadmeteo Leave a comment

This weekend marks the halfway point through winter. Though December brought some snow January has been broadly average – really cold air has been absent with only one air frost recorded this month.

The cloudy, anticyclonic type weather is about to be replaced, however, with cold, polar maritime air this week set to flood down from the north-west.

Since December 1st, Wanstead has recorded 12 air frosts – about average. The coldest night was just -3.7C. The current mean temperature this winter to January 14th is 5.7C with rainfall 111mm – statistics that are remarkably similar to the winters of 2012/13 and 1990/91. Both those seasons were followed by cold late winters, February 1991 saw some of the deepest snow that I’ve ever seen in the south-east; the mean temp for that February finished 1.6C, the 14th coldest in the local series going back to 1797.

Using my method for finding patterns stretching back over 50 years to forecast this winter I picked out years that were +/- 10% of the 2017/18 total rainfall. From these I then weeded out the seasons where the average temperature was +/- 10% of the 2017/18 mean.

This gave a list of just two other winters with similar temperature and rainfall. Both winters had above average ‘snow lying’ days, the long terms average for this area being six.

Before any readers accuse me of going all Daily Express with the title of this blog I would emphasise that this piece doesn’t echo the latest long-term output from the models, which are in a state of flux, caused mostly by the evolution of the explosive cyclogenesis expected midweek. It is simply a reflection of what the local data is telling me.

A 100% guarantee of snow isn’t such a fantastical claim as, during the past 10 years, there is only one winter when no snow fell or was lying at 9am!

In terms of the rest of the winter, outside of the models, I would expect a couple more snowfall episodes, similar to the ones we had in January and February 2013. A repeat of February 1991, while not impossible, looks unlikely – there seems to be far too much energy coming from the Atlantic to allow the all important Scandinavian / Russian high to form and exert its influence far enough west for long-lasting cold and snow.

Annual review of weather, Lido, London weather, Weather

Wanstead Weather: 2017 review

January 5, 2018 wansteadmeteo Leave a comment

This year finished as the 10th warmest on record – some 0.7C warmer than the 1981-2010 average.

Only three months of 2017 were roughly average – the means being within +/-0.7 every month, bringing the mean temperature to 11.9C.

Rainfall was less remarkable with the year finishing roughly average. The total of 607mm (101% of 1981-2010 average) puts it as the 119th wettest since 1797, just over 40mm wetter than 2016.

It was also a slightly duller than average year with 1,391.2 hours of sunshine recorded. That’s 94 per cent of average, the 91st sunniest since 1881.

For a review of each month, click January, February, March, April, May, June, July, August, September, October, November, December

To view full stats follow this link:http://1drv.ms/1kiTuzv

You can read the national review of weather events at the Met Office blog here.

London weather, Weather

London’s January extremes since 1959

January 4, 2018 wansteadmeteo 3 Comments

I’ve put together a few top 10s of stats for Wanstead, St James’s Park and Heathrow for the month of January.

Probably most notable is just how impressive the depth of cold was during the cold spell of 1987. When considering St James’s Park the temperature on the 12th never rose above -6C: nearly 4C colder than any January day in 1963, the coldest winter in modern times.

My winter forecast for the London area can be found here.

Some national UK January values according to TORRO

Hottest: 18.3C Aber, Gwynedd – 27th 1958
Coldest: -27.2C Braemar, Grampian – 10th 1982
Wettest: 238.4mm Loch Sloy main adit Strathclyde – 17th 1974

Climatology

Here’s a couple of graphs showing the maxima, minima and rainfall. Notice the spike which reflects the singularity which has an 84 per cent probability.

London weather, Monthly Review, monthly summary, Weather

December 2017: average temps, wet

January 3, 2018 wansteadmeteo 3 Comments

December 2017 was a wet month. Just over 83mm of rain was recorded, 157 per cent of average, the wettest December since 2012 and the 38th wettest since 1797.

Screen Shot 2018-01-03 at 19.30.21 — The snow depth on December 10th reached 5cm at its maximum

The monthly mean finished 5.6C, precisely average and the coolest December for five years.

Some 48 hours of sunshine were recorded, 120 per cent of average, slightly less than last year.

The most notable event was the on December 10th which produced the best snowfall in 5 years

Air frosts: 10. Ground frosts: 14. Snow falling: 2. Snow lying: 1.

January (on the 3rd) is looking like it may produce more snowfall events similar to December though, with models suggesting a build in heights to the north. A look at the output, including GFS and ECM, suggests the UK will be in a battleground between a cold airmass to the east and warm Atlantic air to the west.

It would seem to back up my winter forecast and also the December analogues with nothing warmer than average.

Average: 33%
Rather cold: 17%
Cold: 17%
Very cold: 0%
Severe: 33%

Full stats for December here:http://1drv.ms/1rSfT7Y

Summary for December 2017

Temperature (°C):

Mean (1 minute) 5.8

Mean (min+max) 5.5

Mean Minimum 2.8

Mean Maximum 8.3

Minimum -3.7 day 11

Maximum 14.2 day 30

Highest Minimum 9.8 day 21

Lowest Maximum 2.4 day 10

Air frosts 10

Rainfall (mm):

Total for month 83.7

Wettest day 14.6 day 10

High rain rate 12.1 day 31

Rain days 21

Dry days 10

Wind (mph):

Highest Gust 25.1 day 30

Average Speed 3.5

Wind Run 2570.0 miles

Gale days 0

Pressure (mb):

Maximum 1036.4 day 22

Minimum 970.3 day 10

Days with snow falling 3

Days with snow lying at 0900 1

Total hours of sunshine 48.3 (120%)

UK snowfall, Weather

Hyperlocal forecasting of snow

December 27, 2017 wansteadmeteo 4 Comments

The knife-edge situation for snowfall across England today set me off wondering if there was a way to forecast snow locally to a given location.

Temperature, dew point and altitude are all crucial to forecasting snow, as is precipitation intensity that can lower the wet bulb temperature, the ‘rain turning to snow’ scenario. Less well known is the role air pressure plays in these events, such as the one on December 10th which caught many forecasters by surprise by its intensity.

While various models continually improve in their skill at warning us of impending rain / snow events that often cause chaos, their resolution can still struggle and especially when the event more or less becomes a nowcast.

In the International Standard Atmosphere (ISA) there is a 1 hPa difference for each 30 feet vertical change in height in the lower levels.

If we take a forecast pressure as 970 hPa, the difference between standard conditions (1000 hPa) and 970 hPa is thus: 30 hPa

30 hPa * 30 = 900ft height variation.

You then consider local altitude: in my case 18m (59ft)

So 59ft – 900ft = 841ft (256m)

A simple table, therefore, to consider air pressure is thus.

1000 hPa = 0m
995 hPa = 27.6m
990 hPa = 73.3m
985 hPa = 119.1m
980 hPa = 164.8m
975 hPa = 210.5m
970 hPa = 256.2m
965 hPa = 301.9m
960 hPa = 347.7m
955 hPa = 393.4m
950 hPa = 439.1m

Looking at the system today the pressure rose quickly after the centre passed, leading to a 1hr (at best) window of snow falling. As the pressure rose, and the temperature picked up only slightly the snow turned back to sleet and then rain.