The anticyclone developed further yesterday with a maximum pressure of 1039.4mb, the highest reading since March 2015. This produced an exceptionally still day with extended periods that produced just the briefest movement of air and a maximum of only 7mph. The temperatures have fallen a little for the fourth day with a maximum of 7.9C, close to the mean for December and a minimum of 4.4C that occurred just after 10am yesterday. This had risen to 5.9C at 08.00 today.
The thick fog of yesterday took until after 1pm to slowly lift into mist from the low clouds and has thinned a little more this morning. The little breeze in evidence this morning would indicate that it has changed direction from a south-easterly, that has dominated for the past week, to come from a north-westerly direction.
Author: Eric Gilbert
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Exceptionally still conditions
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Intense high pressure
If your wall barometer is almost off the scale (high) it is indicating correctly. For the past twenty-four hours the barometric pressure has been rising rapidly, to the highest since April 2015, with a reading of 1037.0 at 08.00. With little wind, maximum gust overnight was 10mph, daytime 7mph, the stagnant air is trapped below the anticyclone. For long periods the air has been still. As a result thick fog has formed with visibility down to 100m this morning.
Both maximum (9.4C) and minimum (5.3C) in the past twenty-four hours are down again but both still well above the mean for December. -
Early mist and drifting fog
Today has dawned with another overcast but mild day. There was a brief interlude at daybreak when the sky cleared and the temperature dropped, which temporarily caused mist and drifting fog to form. However by 08.00 the sky was again cloudy as the fog thinned.
Yesterday the temperature was down on previous days with a maximum of 9.9C, still well above the mean for December. The overnight minimum occurred at 07.37 this morning with a low of 5.7C, also well above the mean minimum.
It is still a relatively dry month as half way through December the total rainfall is 14.9mm with the 32-year average standing at 91.5mm. -
Dark, Damp, Dismal morning – again!
It was a treat to have a day with almost continuous sunshine yesterday amounting to 5.13 hours, if a little hazy at times. The sunshine pushed the thermometer to 12.0C, almost 4.5C above the mean due to the mild south-easterly breeze peaking at 18mph. The large area of high pressure over the continent is reluctant to give way with a barometric pressure of 1017.8mb at 08.00 hours. This is allowing the mild and moist air from around the Azores to drift across the country.
The minimum temperature occurred at 22.22 hours with a reading of 6.1C when increasing cloud raised this to 9.1C at 08.00 hours. This morning has dawned with low cloud over the hills and dampness in the air but not raining – dark, damp and dismal. -
Minimum higher than mean maximum for December
Yesterday was another dull, overcast day with no sunshine and occasional showers that amounted to 1.2mm. However, the mild and moist air from the Azores meant another warm day with a maximum of 12.1C that is almost 5C above the mean. The temperature very slowly fell during the afternoon but by midnight was still above 10C. By 08.00 the thermometer read 8.1C, the lowest for the last twenty-four hours, which is 6C above the mean minimum for December and 0.5C above the mean maximum for December.
The barometer now reads 1017.5mb, the lowest pressure this month as the anticyclone that dominated the early part of the month, very slowly declines allowing weather fronts to slowly cross the country.