Tuesday 13th October
Monday was best forgotten as the very wide weather front meant light rain and drizzle persisted almost all day that resulted in a maximum of 17.8C at 15.50. This high was 2.9C above average thanks to the flow of warm air from the southeast that contained a little warmth from the Continent. The many hours of very light precipitation amounted to just 1.4mm.
Unusually overnight the thermometer stopped dropping at 23.59 with a minimum of 15.0C, which was a significant 7.5C above average. The thermometer then made an about turn and began to slowly rise again as the warmer air arrived, reaching 17.2C by 08.00, which was already 2.1C above the average October maximum.
Tuesday arrived dull under a very low cloud base thanks to another weather front that will likely clear by mid-morning.The first light rain arrived at 08.02. The weather front is quite narrow and fragmented that produced a gust of 20mph at 05.07 ahead of the front arriving. The wind dropped down again as the weather front passed over and will back into the west as the day progresses.
The weather will clear behind the weather front with some warm, autumn sunshine reappearing. The down side will be a clear night that will produce a cold night with the minimum back into single figures. This will be followed by a dry and sunny day.
We are now beginning to feel the effect of very warm air that has been arriving from mid-Atlantic where the remains of ex-hurricane Isaias is moving steadily northwest, being absorbed into a depression coming out of Canada, that will arrive close to Iceland by Wednesday. A high pressure has built to the southwest and over the Continent that will continue the drift of warm air across the UK until Friday.
The weather system is being “fuelled” by a temperature contrast either side of the jet stream close to North America, with cold air to the north and warm air to the south.
Crucially, some of the warm conditions on the south side are coming from where Hurricane Isaias is making landfall in the US. Hence, Isaias is powering the weather system towards the UK.
The forecast pressure charts indicate that by Friday the centre of the high pressure will have withdrawn to the west of the country, mid-Atlantic, that will result in a much cooler air stream coming around its northern flank, originating near Iceland, that will result in maximum temperatures dropping significantly from those of this week, to be close to the October average again.