Tuesday 20th January
Monday was another of the dark and gloomy days under the thick cloud cover, but it was mild for January. The thermometer eventually rose to a maximum of 9.4C at 13.42 being 2.3C above average. The past night was also a repeat of recent days as there was little change in temperature with a minimum of 7.1C at 07.52 early Tuesday, being 5.9C above average. The diurnal range of temperature was just 2.3C. There was a slight fall in temperature during the early evening but an increased drop between 21.00 and midnight with a minimum of 7.1C at 07.52.
The month so far has brought us a cold spell at the beginning and recently a mild spell. The average maximum at this stage in the month is 0.5C below my long-term average and the minimum is 0.8C below.
Tuesday began with some brightness from gaps in the cloud with the cloud cover 7/8th at 08.00, but much thicker cloud is closing in.
A vigorous deep depression is heading our way, my instruments indicate that there has been a rise in wind strength since around 02.00, with a blustery day ahead. This afternoon will see a weather front, associated with the depression, arrive bringing substantial rainfall, probably arriving late afternoon. All the while the wind will increase from the southeast. The second half of the attack will be on Wednesday morning with a repeat of strong winds and several hours of rainfall. The forecast barometric pressure at the centre of the depression is forecast to be 977mb, which if correct, will be the lowest pressure this month, hence the increase in wind strength due to the increased pressure gradient as the air rushes from the high in the east and low to the west.
The forecast track of the jet steam seems to indicate that by Sunday it will become less fragmented and move a little further south, probably allowing a stream of cold air to arrive from the east. The first indication will see the wind back from the southeast, as over the past four days, to east on Saturday, from where it is likely to remain for a week, bringing much cooler, if not much colder weather. There is growing confidence that next week we will see a distinct change from our recent mild days and nights with below average maxima and possible air frosts at night.
Although it is going to get colder there are the first signs that nature is responding to the lighter days and the recent few milder days.