Max Temperature Irrelevance

According to a local station on wunderground, local daytime temps exceeded 28C, reaching a high of just under 35C which would be an all time record if the station was any where near the established standard. On average the wunderground stations are 2-3C above official Met Office weather stations, due to siting issues and massive UHI from an abundance of concrete and asphalt.  As it is, over at Tallbloke’s Talkshop Tim Channon has spent a long time looking at official stations, hardly pristine sites, and found them wanting. The Met Office have made much of this recent spell of high pressure heat, running updates on their site about the “highest temperature this year”.

tchannon on July 25, 2013 at 5:57 pm

Met Office: -Weather report

High temperatures in July.The United Kingdom saw a prolonged period of high temperatures between Saturday 6 July and Thursday 24 July. A maximum temperature of 28 C or more was recorded at one or more location on each of those 19 days. The last time the UK saw such a long period of hot weather was August 1997 which also had a 19 day run of high temperatures. Temperatures are not expected to reach 28 C today. Issued at 1032 on Thu 25 Jul 2013.

So they are using a magical 28C as a marker.

Bit of bother there… they ain’t got no consistent stations nor equipment.How about revealing the raw evidence, all of it?

I concur. Hot yes but within expected parameters for these shores.

This is the past four days of local station data of dubious quality but still useful to see changes. The thick blue line is to show the time above 80F and the ‘amplitude’ change as the heat and clear skies were broken by storms which came 22nd- although it did not rain until here until the early hours of the 25th* although other localised storms have passed passed close enough to see, hear and smell.

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* the system of storms coming from N France appeared, on the radar, to split along the M3 with energy diverted mostly to the West with some East towards North and West London. This picture is looking West. Most of the real action followed a few hours later, this was merely the scouting party.

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There were originally three  building in the area circled which were sheared off. The two almost verticle spears of cloud (left of circle) seem to show the wind shear which may be due to topography or general instability. I’m inclined to the former causing the later based on previous storm systems clipping. The day started with a NNE flow which drifted to SW with the arrival of the weather system pictured.