Friday 21st August
There were numerous showers drifting across the country on Thursday but as usual, they were averse to dropping any significant precipitation on Marlborough. There were a couple of times when for a minute a few drops dampened the ground mid-afternoon and early evening that amounted to 0.6mm. However, as soon as the sun reappeared the ground dried up rapidly. The high of 22.2C was logged at 14.30 being 0.6C above average whilst the low of 9.4C was 2.4C below average, recorded at 06.37.
Friday at first light revealed that a bank of fog had formed in the early hours due to the recent moisture in the air condensing as the temperature dropped, that included thicker radiation fog in the River Og valley. By 06.15 the visibility across the River Og valley was restricted to about 400m whilst less dense towards Savernake Forest. By 06.30 the sun had begun to creep above the fog bank and visibility slowly improved. By 08.00 the thermometer had risen to 12.9C making it the coolest start to a new day at that time all month.
The breeze today will be less strong and come from a northerly direction, circulating around the top of the high pressure, that will produce a cool day and probably the first day this month with a maximum below average. The forecast charts indicate that a large area of cloud will drift down across the country from the Northwest today, probably from around mid-day, from the back edge of the departing low pressure system. This will limit the sunshine and thus the rise in temperature.
The anticyclone has been slowly building over the past twenty-four hours, as the low pressure moves away eastwards towards Scandinavia, which will continue over the weekend. The centre of the high pressure tomorrow will be over the UK that will give us a fine, dry and slightly warmer couple of days, back to around the average for late August.
The soil temperature over recent days, positioned at a depth of 5cm and read daily at 08.00, has been a good indicator of how warmth has been leaving the ground. The last four mornings have read 21.6C, 19.2C, 17.5C and 15.7C respectively, after a high of 24.2C on the 13th. This was principally due to lower night temperatures combined with the minimal rainfall moisture evaporating into the atmosphere and in doing so taking a little warmth with it.
There have been comments over the past month or so of the El Niño weather phenomenon building in the Pacific. This item was published recently.
Ben Rich, Lead Weather Presenter and Mark Poynting, Climate Journalist
5 hours ago
The El Niño event that is developing over the Pacific Ocean is likely to be the strongest in living memory, the Met Office has warned.
The powerful natural climate phenomenon pushes up global temperatures and can increase the risks of extreme weather.
Added to the effects of human-induced climate change, the Met Office is warning that it is “very likely” to mean 2027 is the hottest year on record.
There is growing evidence that weather patterns around the world are already being affected, with below-average monsoon rains in India and suppressed hurricane activity in the Atlantic Ocean.
El Niño could put the UK at greater risk of a wet, stormy autumn.
“We should be clear that this is an unprecedented event”, said Prof Adam Scaife, head of long-range forecasting at the UK Met Office.
“I have never seen an El Niño signal this intense in our forecasts.”