Months of snow on way? It’s too early to tell

Sections of the tabloid media have been going into overdrive these past couple of weeks with tales that the UK will soon be in the grip of an Arctic freeze – one headline in the Daily Express boasted that parts of the UK were in for FOUR MONTHS OF SNOW.

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The Daily Express ‘forecast’ was published at the end of September

These stories are nothing new though they seem to be published earlier and earlier in the autumn. By the time we reach November – once the traditional time when winter forecasts started appearing – the tabloids have already turned their attentions to spring. Much of it is just ‘clickbait’ – a means for publishers to prove their stories are being read to keep their advertisers happy, a symptom of an industry in financial dire straits.

There will be snow somewhere in the UK during the next five months but predicting heavy snowfall in a given area, such as London, is impossible. But given the outrageous claims at such a long way from the start of the season on December 1st I decided to have a look to see if there is anything wintry on the horizon.

I started by comparing a range of historic datasets, including quasi-biennial oscillation (QBO) and el niño–southern oscillation (ENSO), against monthly mean temperature and rainfall anomalies. Because ENSO data only goes back to 1950 the findings are obviously far more restricted than my winter forecast method which uses local data going back to 1797.

The results of my data trawl are underwhelming. The best fit years were as follows:

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For anyone who likes snow the above is not encouraging, however, given the past year which has seen several daily and monthly records shattered, including a record warm December, who’s to say that recent warm temperatures will suddenly swing the other way.

The above table would also suggest that the coming winter will be colder and snowier than the previous three – but that gives little away given how mild the past three winters have been.

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October 2016 has seen a strong blocking high become established over Scandinavia, the earliest this has happened since 1881.

A study of mean temperature anomalies in London since 1950 suggest that sudden swings, both positive and negative, are becoming more likely. Last month was the fifth month in a row that I recorded a positive anomaly – the longer this goes on the more likely it is the mean could turn negative – though bear in mind that I have recorded 12 months in a row of positive anomalies, from February 2011 until January 2012.

Current weather also suggests that something maybe afoot with the earliest establishment of a strong anticyclone over Norway (the fabled Scandinavian high) since 1881! This weather pattern gives the south-east its best chance of snow with the feed of cold air often coming all the way from Siberia. Time and again, however, I’ve seen these patterns break down in November just as everyone starts talking about an imminent severe winter. There is more than an element of truth to the saying:

Ice in November to bear a duck, rest of winter will be slush and muck

In conclusion, while the early figures look bleak for snow in the low-lying south-east, it is still far too early to tell if the coming winter will be mild or cold.

 

 

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September 2016: very warm, very dry

Last month was the second warmest September in a local record going back to 1797! The monthly mean finished 17.8C, 2.4C above average. Despite being an ‘autumn’ month September was actually a full degree warmer than June!

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September 2016 was the second warmest in a local record back to 1797, though we’re talking by fewer than tenths of a degree.

The hottest September day since 1959 was recorded on the 13th when 33.1C was reached, the sixth equal hottest in the local daily record back to 1848.

The month also saw the warmest minimum recorded since 1959 when the mercury failed to fall below 18.7C on the 6th.

It was another very dry month, the third much drier than average month in a row: just 27.7mm fell, 24 per cent of average, making it the driest September since since 2007 and the 12th driest in the local record.

Like August, the month only falls down in terms of impressiveness when sunshine hours are considered. Some 119 hours were recorded, that’s 85 per cent of average, making it the dullest September for 15 years.

Air frosts: 0, Ground frosts: 0

So what has September got in store weatherwise? The models on the 1st suggest that a large Scandinavian high will become established to our NE bringing lots of settled weather and showers on coasts. There’s obviously the chance of trough disruption as the month progresses if the anticyclone’s influence declines.

Beyond the grasp of the models my usual long range outlook method falls down this month due to September’s warmth and dryness – there is nothing within  +/- 10% of September’s statistics. I would guess, however, that we are looking at another drier than average month with frost becoming a risk as the month progresses where skies clear. There is also the chance of more pleasant autumn days where skies are clear during the day.

My September outlook for temperature was poor. I predicted a mean of 15.3C (outcome: 17.8C). It was much, much drier than I thought: 300mm (outcome: 27.7mm). Sunshine was poor: 140 hours (outcome: 119 hours).

Here follows the full weather diary for September…Full stats for the month here:http://1drv.ms/1rSfT7Y

1st: Sunny start but cloud gradually increased until it was overcast by 6pm. Clear spells overnight but warmer than previous nights.
2nd: Cloudy though some brighter intervals.
3rd: Sunny start, cloud began to pile in at 12.30pm with rain arriving at 5.30pm, this fell through the evening with some showers in the early hours.
4th: Bright, breezy start but rapidly turning cloudy and dull. Some rain overnight.
5th: Light rain and dull to start – this quickly clearing to cloud by 3pm. Things remained cloudy with a muggy night.
6th: Cloudy, dull and muggy start after warmest September night on record. Another warm night though muggy.screen-shot-2016-10-01-at-12-22-03
7th: Cloudy to 11am though sun breaking through as drier air arrived. Feeling humid.
8th: Sunny start but with plenty of cumulus, this quickly decreasing to leave clear sky.
9th: Cloudy morning though sky seemed to periodically clear of low cumulus before becoming overcast and very breezy in the afternoon. Some rain overnight and just before obs time.
10th: Cloudy start with patchy light rain, this briefly turning  heavy at 1pm  before turning occasionally moderate. Dreadful afternoon after recently. Clearing overnight to leave a sunny start.
11th: A glorious sunny day with only the odd patch of cirrus.
12th: Bright start with some sunshine, clouding over with a few splodges of rain with warm front. Then sunny and very warm.
13th: Sunny start with a few cirrus and castalanus around. Breezy at times with the thermals. The warmest September day since 1959 and 6th equal warmest since 1848.screen-shot-2016-10-01-at-12-13-54
14th: Sunny start with a few cirrus. A few patches of alto-cumulus later. Very warm but not as hot as yesterday. Warm, pleasant evening.
15th: Sunny with a few wispy cumulus, clearing to hot sunshine. Some alto-cumulus developed at 2pm and towering cumulus could be seen in distance. Thunderstorms reporting to NW of London. Cloudy and warm overnight with eight peals of thunder in the early hours and heavy rain.
16th: Light to moderate rain through the morning, petering out at 1.30pm.
17th: Cloudy, cool and breezy all day, at times dull.
18th: Cloudy all day, a bit warmer than the previous two days.
19th: Cloudy start though with sun breaking through briefly at 11am until 1pm then cloudy again. Rain at 1am that didn’t last long enough to register.
20th: Cloudy and fairly calm – a nothing day with odd very light drizzle.
21st: Bright start with cloud breaking to long spells of sunshine before more cloud moved in. Warmer than of late.
22nd: Cloudy but  sun broke through giving pleasant afternoon and cool overnight.
23rd: Sunny, gin clear and cold start. Just a few fair weather cumulus through the day.
24th: Sunny start with cloud decreasing. Very warm in sun but cloud and breeze built through the day. Overnight light rain between 6am and 9am.
25th: Bright start after overnight light rain.
26th: Bright start with a few cloud breaks here and there. Heavy shower at 12.15pm with further threat of rain but stayed dry.
27th: Bright start with signs of a cold front moving in from south then cloudy.
28th: Sunny start with patchy cirrus, this tending to thicken at lunchtime to turn mostly overcast with humidity increasing. Breeze also picked up with reappearance of sun mid afternoon. Cloudy, very mild and breezy rest of the day.
29th: Cold front and brief heavy rain swept in at 10.03am. Then intermittent falls until 11.23am.
30th: Sunny, gin-clear start, patchy cumulus bubbling up at 10.30am. Cloud grew thicker around 12 noon with brief shower at 1pm. Then sunny spells and cloudier periods. Another shower just after nightfall then clear. Cloud moved in after 2am with another shower. Early sunshine  gave way to moderate showers around 9.45am.