UK and London Weather 23/01/2012-29/01/2012

We kicked off the past week under a flat ridge of high pressure over most of the UK, which brought dry and sunny spells to London on Monday the 23rd. There was a light breeze with the temperature remaining around average for this time of year, maxing out at 9C and dropping to -1C at night, bringing a widespread frost to much of the southeast. The BT tower station recorded calm conditions with very little variation during this time.

An interesting feature was that in the early hours of the morning on the 24th, the Met Office UKV output was forecasting a boundary layer depth well below 500m for all of the IOP sites, likely due to the cold, frosty temperatures. This could potentially have kept a greater concentration of overnight pollutants at the surface.

But by the 24th and 25th, precipitation a cloudier weather began to spread eastwards and two warm fronts advanced across the UK from Ireland. This brought milder overnight temperatures of around 6C and occasional light rain and drizzle. On these days the BT tower recorded morning rush hour CO2 peaks between 8 and 10 as would be expected, but also of note on the 24th was an increase in sensible heat and turbulent kinetic energy from the surface between 2pm and 6pm, perhaps caused by a clearing of cloud cover increasing the shortwave radiation reaching the urban surface.

These milder warm-sector conditions persisted into the early morning of Thursday the 26th, when a passing cold front then brought some locally heavy showers to England but London itself remained relatively fair with only some cloud and maximum temperatures of around 8C.

The 27th saw a complex region of low pressure with numerous organised showers to the North of the UK, but London remained quite dry with only some showers developing in the afternoon, and mistier conditions overnight.

Another noteworthy event was the early fog observed in London on the 29th until sunrise, when it cleared, but the Sunday remained cold at around 4C, with a brief shower observed at 5pm.

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

Comments are closed.