UK and London Weather 30/01/2012-05/02/2012

We certainly ended the past week on a wintry note across most of the country, but lets take a look back to the 30th of January first. The UK was, and continued to be, under the influence of intense high pressure over eastern Europe, keeping the country in a cold continental airmass that inhibited the warm fronts approaching from the west off the Atlantic. During this time London was mostly cloudy with maximum temperatures around 4C, dropping to around -1C as broken cloud and clear spells developed overnight. On this day at the BT tower, the turbulence levels were fairly low, with the turbulent kinetic energy and vertical velocity variance rarely getting above 1.5m2/s2

On Tuesday the 31st some mist and fog was observed prior to 6am in London eventually giving way to some slightly wintry showers and scattered cloud. With cold winds being variable from the Northeast the temperatures did not get much above 2C. It continued to be cloudy on the Wednesday with temperatures peaking around 3C, and the Met Office’s UM UKV model output for this day was predicting boundary layer heights between 800 and 1200m for most of the IOP sites (deepest at KCL), apart from Dettling where it was predicted to be between 400 and 600m. The signatures of the cold weather can be seen in the radiative measurements from the BT tower, where the sensible heat remained well below 100W/m2  for most of the week and raely grew to more than 200W/m2.

By the Thursday the 2nd, high pressure was still the dominant feature affecting the UK (see figure below), bringing cold Easterlies to most places, however because of this the day was dry and clear with only occasional snow flurries at highr ground in England. London was cold and dry with frost forming in most areas. The mamum temperatures barely reached 2C and dropped to -5C in less urbanised areas on Thursday night, leading to further frost. At this point the Met Office labelled the past few days as “the coldest spell of winter thus far”.

Interestingly, the Met Office’s UKV output was predicting quite deep boundary layer depths of around 4000m at bht Chilbolton and the KCL sites on the Friday, while the day in London was similarly dry, cold and clear as before. But by this point the possibility of more widespread snowfall was starting to crop up in the news, with more “disruption” and “big freezes being anticipated.

Saturday began in London with the weather being partly cloudy and the mercury reading about -2C, hovering around -1C for most of the day. The weather was mostly dull and partly cloudy until, at last, around 7pm some light snowfall began, which continued on and off through the night until 5am on Sunday, leaving between 3 or 5 inches lying across much of the city. Throughout yesterday on Sunday the 5th of February, fog patches were frequently observed across London due to the surface cooling effect of the snow.

The 2nd of February weather forecast from the Met Office, valid at 12UTC

You can follow any responses to this entry through the RSS 2.0 feed. Both comments and pings are currently closed.

Comments are closed.