Tag Archives: monthly review

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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June 2014: warm and dry

June 2014 continued this year’s theme of being milder than normal; the mean temperature of 17.1C was 1C above average, making it the 22nd warmest June since 1797.

little fluffy clouds
June was marked by some spectacular cloudscapes and sunsets. This was the view across Wanstead Flats from Centre Road looking toward Ilford on the 21st

June, like  March and April, was dryer than average with just 15.2mm of rain, that’s just under 30 per cent of average.

The driest June since 2000 started off unsettled with frequent rain – 6mm falling on the 3rd. The following day was cool with the temperature reaching just 16.2C.

Though there were nine days when over 10 hours of sunshine was recorded the magic 80F was surpassed just once: on the 9th when 27.5C was reached under 6 hours of sunshine. This sunniest day was the 10th when 14 hours of sunshine nudged the thermometer to 24.5C. Overall there were 214.1 hours of sunshine – that’s 120% of average, the sunniest since 2011.

On many days during June, including the 30th shown here, the sky turned dark but just spits and spots of rain were often produced
On many days during June, including the 30th shown here, the sky turned dark but just spits and spots of rain were often produced

Despite plenty of potential no incidents of thunder were recorded – the much-hyped weekend of the 7th / 8th saw less than 2mm of rain – all of the action staying well to our east in the France, Germany and the Low Countries. Further thundery potential on the 13th failed to produce anything in this area though a disturbance over Berkshire saw thunderstorms develop in the Oxford, Reading, Basingstoke and Wokingham region, with up to 38mm of rain falling over a wide area.

It is a typical feature of summer that rainfall can vary a great deal across a small area. The nearest official station to Wanstead, St James’s Park 8.4 miles to our south-west, recorded 33.8mm – more than double what fell here.

Some nights were chilly when the sky cleared but there was no air frost or ground frost.

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

Yet another occasion of impressive cloud formation during June included this example of late evening cirrus. The formation, seen at ground level, seemed similar to a display of the Aurora
Yet another occasion of impressive cloud formation during June included this example of late evening cirrus. The formation, seen at ground level, seemed similar to a display of the Aurora
Circumhorizontal arc over Aldersbrook
Circumhorizontal arc over Aldersbrook

April 2014: Another mild and dry month

April 2014 continued this year’s theme of being milder than normal; the mean temperature of 12C was 2.2C above average, making it the third warmest April since 1797.

Though many days were stunningly sunny the breeze made it feel chilly
Though many days were stunningly sunny the breeze made it feel chilly

April continued the dry theme of March and was indeed dryer on average. Just 19.6mm on rain fell over the 30 days – that’s 46 per cent of average.

The month saw some stunningly sunny days during the second week into the third week, though these were tempered by chilly east to north-easterly winds. The warmest day was the 21st when 21.5C was reached – the first ^70F temperature of the year.

Though it ‘felt’ quite a sunny month the 150 hours recorded was only 94 per cent of average.

Some nights were chilly when the sky cleared but there was no air frost and only two ground frosts, on the 15th and 16th

To view full stats follow this link:http://1drv.ms/1cBRoH3