Tag Archives: monthly stats

May 2015: average temps and dry

After a sunny and dry April last month was disappointing for anyone looking for prolonged heat and sunshine. Indeed the month saw nearly two dozen less hours of sunshine than April.

During a very thundery day nationwide on 19th it was bright and sunny looking west on Southwark Bridge at 3.40pm...
During a very thundery day nationwide on 19th it was bright and sunny looking west on Southwark Bridge at 3.40pm…

Maximum temperatures were low for May – the highest being just 23.3C on 11th, 2C colder than the highest temperature in April.

Mean temperature for the month was 13.4C, 0.3C above the 1981-2010 mean. Rainfall of 38.9mm was 76% of average – six of the last seven Mays have been notably dry.

There were 178.5 hours of sunshine recorded in this area which is 98% of what we can expect to see during an average May. The wettest day occurred on the 4th with 8.2mm.

So what has June got in store weatherwise? The models this morning (June 1st) suggest a very unsettled start to the month before the Azores high builds a ridge to quieten things down for a couple of days. Beyond that is uncertain – the ensembles point to a very mixed picture with no clear trend shown to where we might be in a fortnight’s time.

Looking east was a different story which revealed a distant thunderstorm
Looking east was a different story which revealed a distant thunderstorm

Looking at the month as a whole my long range method suggests June will be average in terms of temperature: 54% probability. The next highest chance is for rather cool at 15% probability. If you add the probabilities together the chance of average to below average temperature is 85% – which would seem to rule out a ‘very warm’ month…

Rainfall is looking average to slightly above average, though at only 62% probability. It looks like another broadly average month in terms of sunshine.

So with a slightly changeable start to the month we can look forward to another average month without prolonged heatwaves?

My May outlook was good in that it saw the high chance (80%) of average temperatures. I was, however, out with the low rainfall – the signal was for something greater than average. Sunshine, as already mentioned, was also out – my forecast was for something 1.2 above average.

May 19th was a very thundery day across eastern England. This picture was taken looking east from Southwark
May 19th was a very thundery day across eastern England. This picture was taken looking east from Southwark

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

Here follows the full weather diary for May…

1st: Sunny start but cloud quickly filled in. Though cloudy it remained bright. Cold wind.
2nd: Cloudy start but becoming brighter. Turned to hazy sun at 3.30pm but then turned cloudier. Rain by early hours, 5am and then again at 8.30am.
3rd: Cloudy after early rain then growing warm and muggy with sunshine at 2pm. It stayed bright and muggy into the evening.
4th: Sunny start then haze and cumulus soon thickened before clearing to sunny spells early lunchtime. Cloud built up again at 2pm. Rain spread in early evening with heavy bursts from 11pm to 1.30am – heaviest at midnight.
5th Cloudy start but becoming brighter albeit very windy through the morning and past lunchtime. Occasional showers with very heavy shower at 6am.
6th: Cloudy start with brighter interludes but turning very blustery with occasional light showers. These turned heavier through the day with a notable one at 2pm. Thunder heard at 5pm with more showers.
7th: Sunny start but with lots of cloud bubbling up

Wanstead was hit head-on by a thunderstorm at 2pm on 19th, clearly shown on this radar picture. Because the storms were fast moving rainfall accumulation was not remarkable
Wanstead was hit head-on by a thunderstorm at 2pm on 19th, clearly shown on this radar picture. Because the storms were fast moving rainfall accumulation was not remarkable

8th: Bright start after early light shower. Spots of rain during bright afternoon – these turned heavier at 3.30pm. Cloudy and mild overnight.
9th: Bright, slightly breezy start. Spells of very warm sunshine though also odd spots of rain during showers.
10th: Bright start with sunny spells through the day
11th: Bright start with altocumulus. Cloud broke to sunny spells though sky was very hazy at times. Feeling humid. Warm overnight but short, sharp shower moved in 10 minutes before obs time.
12th: Light rain to start from a frontal feature. This clearing to sunny spells and pleasant afternoon
13th: Sunny with few cirrus to start. More cloud bubbling up later. Clear at first overnight before cloud and light rain moved in before 9am.
14th: Cloudy but spits and spots of rain spread in, before more steady light rain at 10.30. This eased at noon before becoming heavier again at 3.30pm and rained into evening, easing up at midnight.
15th: Sunny start though cloud tended to fill in. Some rain around midnight
16th: Cloudy start though got progressively sunnier as cold front cleared, humidity fell and cloud melted away. Very pleasant. Cool overnight.
17th: Sunny, clear start with a few cirrus. Cloudier at times but still sunny spells. VERY breezy with f4/5 headwinds on ride to station. Rapidly changing skies with wind shear.
18th: Some light rain to start, this intermittent through the morning.
19th: Bright and breezy start. T-storm developed at 2.30pm but moved through quickly. Was two more, at 5pm and 7pm – notable rises in pressure as troughs moved through.
20th: Bright start. Light shower bubbled up late afternoon.
21st: Sunny start, cloud gradually filled in though.
22nd: Bright start with sunny spells. Warm.
23rd: Cloudy with a very thick layer of strato-cumulus making it dull. Two hours of light rain and drizzle followed but cleared to leave it bright with a couple of sunny intervals in the evening. It felt humid at first but turned much fresher once the drizzle cleared.
24th: Sunny start though cloud filling in to make it bright. Frontal light rain between 3 and 5pm.
25th: Cloudy most of the day, a few bright intervals though spits and spots of drizzle early evening.
26th: Sunny start with fluffy cumulus. Pleasant.
27th: Dry, warm and sunny all day. Heavy rain in York from 3pm to 8pm. Felt chilly in the wind.
28th: Dry, lots of cloud around
29th: Dry start though rain moved in between 11am and 1pm. Then sunny spells and breezy.
30th: Sunny though soon clouded over before clearing again to sunny spells. Mackerel sky observed at 8.30pm. Rain between 2.15am and 6.30am.
31st: Light rain to start with outbreaks throughout the morning. Some brightness mid to late afternoon.

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August 2014 – cool, wet and dull

Anyone hoping for a continuation of June and July’s hot weather would have been left sorely disappointed by last month which was characterised by frequent rain and the coldest August night for over 20 years.

A stunning example of sunlight illuminating the underside of cloud at sunset was seen mid-month
A stunning example of sunlight illuminating the underside of cloud at sunset was seen mid-month

August 2014 was the first month this year to be cooler than average; the mean temperature of 17.2C was 1C below average, making it the 89th warmest August since 1797: 1.6C cooler than last August, the coolest for 7 years.

The month was marked with thunderstorms and heavy downpours, contributing to what was a much wetter than average month – some 76mm fell which is 152% of the monthly average and the wettest for 4 years.

The hottest day occurred on the 7th with 27.3C recorded – nothing special for August and a date that heralded the end of the hot spell during June and July.

A couple of nights were notably cool for August: 5C was recorded during the early hours of the 23rd – the coldest August night since 1993.

Sunshine was below average with 161 hours recorded – that’s 83 per cent of mean. The sunniest day was on the 3rd when 12 hours of sunshine were recorded. Throughout the month there were just 2 days with 10 hours or more of sunshine. There were 4 days with thunder recorded – the average for August is 3.

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

Looking further afield there were many thunderstorms around the UK though many places missed out on the big downpours. It was yet another month where rainfall totals could vary greatly in the space of just a few miles.

On the 9th a station in Woodford Green recorded 24.4mm, double what fell in Wanstead. The legacy of TS Bertha coincided with the end of our extended hot spell – an excellent analysis of this storm can be found here.

There were some spectacular cloud formations not far from here. A particularly good one was seen in Witham. 

Squally storm line approaching Witham, panoramic shot!

Prolonged heavy rain on the 11th caused extensive flooding in Scotland.

On the 14th ‘Biblical’ flooding affected Lewisham in south east London.

On 25th a perfect curl could be seen on a depression centred off the west coast of Irleland. The rain associated with this low pressure brought the month's highest daily rainfall total: 23.4mm (the system bringing 27.5mm) - a thoroughly miserable Bank Holiday Monday where it rained ALL day, from 6am until 9.30pm. It was yet another example of how much even frontal rainfall can vary over a small area.
On 25th a perfect curl could be seen on a depression centred off the west coast of Irleland. The rain associated with this low pressure brought the month’s highest daily rainfall total: 23.4mm (the system bringing 27.5mm) – a thoroughly miserable Bank Holiday Monday where it rained ALL day, from 6am until 9.30pm. It was yet another example of how much even frontal rainfall can vary over a small area.

On 25th a perfect curl could be seen on a depression centred off the west coast of Irleland. The rain associated with this low pressure brought the month’s highest daily rainfall total: 23.4mm (the system bringing 27.5mm) – a thoroughly miserable Bank Holiday Monday where it rained ALL day, from 6am until 9.30pm. It was yet another example of how much even frontal rainfall can vary over a small area with St James Park recording 38.2mm. The top 30 totals for that day can be seen here.

sunset overlooking Wanstead Flats 2nd August
sunset overlooking Wanstead Flats 2nd August

Looking even further afield four people were killed in a flash flood at an Italian festival early on in the month.

 

Wanstead Weather – December 2013

Trees in fog by WansteadMeteo
The beginning of the month started with lots of calm, quiet weather with fog and night frosts. A high pressure inversion so not a proper ‘cold spell’

December was warmer than average with a mean temperature of 6.5C (0.9C above the 30-year average) – ranking it 33rd in the series since 1881. Rainfall of 81.9mm was 154% of average – ranking it 22nd in the series.

The month was 1C warmer than last December – with 84% of the rain that fell in December 2012.

Despite it ‘feeling’ like it has been the stormiest December for some years this month was not as windy as December 2012. To illustrate this the ‘wind run’ for this month (the number of revolutions of the anemometer) was 2408.7 miles. Last December was 2654.5 miles, in other words last December was 10% more windy.

Air frosts: 4

Ground frosts: 11

Thunder: 1

Small hail: 1

MetDesk rain radar for 23rd
The rain on the evening of the 23rd was heaviest to the south and west of us – with 75mm in the Warlingham area of Surrey. Flooding and high winds caused hundreds of thousands of power outs in Sussex and Kent