The cold spell of February 1991 saw unusually deep snowfall in central London. The 20cm recorded at St James’s Park on the 8th was the greatest cover recorded at the site since the severe winter of 1962/63.
Courtesy of the Met Office
My own memory of the event was that the synoptics evolved fairly quickly. I was away at university at the time and had to be back for a family event that weekend. After seeing a forecast predicting that a foot of snow was on the way I jumped on a train a day earlier than planned and returned to London. The following morning all hell had broken loose as deep snow paralysed public transport.
Snow fell on the following 6 days with no thawing as the temperature remained below zero until the 10th. The maximum of the 7th was -3C. By the 9th there was widely 20cm of level powdery snow lying. Getting around was difficult – I remember some drifts during walks into town were thigh high.
The models are showing another knife-edge situation for snow – similar to the ‘rain turning to snow’ event earlier this month. But there are a number of factors working against it this time round, at least for most of us who live between sea level and 30 metres.
The low level supply of air off the continent is much milder this time round. Hamburg and northern Germany on the 9th was some 5C colder than currently.
The air pressure, crucial to bringing that snow line down lower, is forecast to be around 10mb higher this time.
And even if we see settling the soil temps, after the recent mild spell, are still 5C – 10C down to 10cm…
Since the early hours of Sunday I’ve been tracking official sites around London to see how Wanstead fairs in terms of retaining cold temperatures and snow.
The results, comparing hourly obs over 62 hours, show that Wanstead was a degree cooler than St James’s Park, half a degree cooler than Heathrow and marginally cooler than Northholt. Only Kenley, with its whopping 170m of altitude, was cooler.
While half a degree doesn’t sound much it can make all the difference, as we saw at the weekend when some areas recorded inches of snow while others barely a centimetre.
Though the snow has pretty much vanished now it was evident yesterday that the area was far more wintry neighbouring Forest Gate, Leyton and Stratford which had pretty much lost all their cover.
* For anyone who has a fascination for the weather and whether their back garden in the Counties Estate is colder than their mate’s in the Warren Estate I notice that weather stations are now even cheaper and you don’t need to connect to the net via a dedicated PC. A unit from Ventus (the W830) allows you to connect to the amateur weather network Wunderground. The internet dealer Weatherspares has them on offer. (NB. I am not on commission but would be happy to offer anyone advice who wants to buy and set one up.)