Category: Commentary

The thick cloud persisted all day on Wednesday giving us another mild day and night with the misty conditions lifting mid-morning but returning overnight. The high of 9.7C was 1.6C above average whereas the low of 6.2C that occurred at 06.56 early Boxing Day was, which was 3.8C above average.

Thursday after first light revealed the misty conditions again to start the new day with light drizzle falling.

The anticyclone has extended eastwards but still maintains a very high pressure over the UK, hence the lack of breeze to move the humid and stagnant air. The pressure reading at 08.00 was 1035.0mb, the highest since 13th November.

HAPPY CHRISTSMAS

Both the maximum and minimum on Tuesday were well above average thanks to the flow of Tropical Maritime Air brought to us on a light westerly breeze. The maximum of 11.2C at 14.03 was 3.2C above average and the minimum 8.4C easy Christmas Day was a significant 6.0C above average.

Christmas Day revealed misty conditions with the high pressure close by continuing the calm conditions and the flow of warm, moist air brought on a west-southwest light air stream. The barometric pressure at 07.45 was 1032.4mb, and still risingas the centre is over Brittany, being the second highest pressure this month.

Once again it was warmer overnight than the previous day. That was thanks to the Tropical Maritime Air stream replacing the Arctic Maritime air that had brought the cold. The thermometer rose to 6.8C at 14.14 on Monday then dropped away to a low 5.5C at 17.45. At that time the effects of the arrival of the warmer air stream were observed as the thermometer began to slowly recover and rise to a maximum of 9.7C at 08.00 on Tuesday. Drizzle was conserved at 16.00, ahead of the warm front from increased cloud cover that produced 0.6mm of precipitation.

At first light on Tuesday, in addition to the warmer air, it was very humid with 100% humidity logged at 08.00 that had produced foggy conditions limiting visibility in Marlborough to 200m.

The centre of the anticyclone is now over the Bay of Biscay with the air circulating clockwise feeding the warm, moist air, now on a very light westerly.

The Polar Maritime Air that covered the country on Sunday, it originated near Iceland and Greenland, was very cool with the thermometer struggling to reach a maximum of 6.2C at 14.42 being 1.8C below the average. Not surprisingly, a cool night followed that saw the thermometer sink to 3.2C at 07.50 early Monday being 0.8C above the average. It was a dry day with just minimal UV light to trigger the sensor at 0.5.

Monday after dawn revealed a sky covered with thin cloud allowing minimal brightness, better than the recent gloomy days, but no sunshine. Thankfully the recent very strong winds have subsided so minimal wind chill, although feeling cold outside.

As the day progresses, the cloud will thicken as a warm weather front approaches and crosses the UK late Monday. This will result in the temperature rising during the late evening and overnight with some possible precipitation, but not white.

The barometric pressure has risen a significant 20mb over the past twenty-four hours as a very high pressure system mid-Atlantic begins to influence our weather allowing much milder weather to arrive on Tuesday for a few days over Christmas. This will allow a wedge of Tropical Maritime air to flood the country.

The drizzle and light rain coming from the thick low cloud on Saturday was a gloomy period for much of the daylight hours. The modest wind from the west allowed the thermometer to rise to a maximum of 11.6C at 14.05 being 3.5C above the average. However, just after 14.30 brief breaks in the lcd appeared and Hirt bursts of thin sunshine redeemed the day. The minimum of 3.3C overnight occurred at 06.35 early Sunday being 0.9C above average. The drizzle and light rain amounted to 2.8mm taking the monthly total to 55.2mm when the long-term average is 94.0mm.

Thin cloud greeted the new day on Sunday that brought a bright start with the hope of some weak sunshine when the sun rises above the horizon for a few hours and a dry day. The air today is less moist coming from the west-northwest air stream with humidity at 08.00 reading 83%, the second lowest this month after 82% on the 8th, when the wind was very strong and from a northerly quarter.

The wind today has been increasing after a strong gust of 29mph at 02.08 early Sunday. The average ten minute wind speed has increased by 4mph during the past hour, currently averaging 9mph. Once again we are being squeezed between a deep low pressure, now heading between Scandinavia and the Low Countries, and an intense high pressure just north of the Azores. This will see the wind coming from the west-northwest and probably more northwesterly this evening and gusting strongly.