29.0C at Jersey Maison St Louis @1033BST

How odd.

I would have thought the sort of conditions required to produce these ridiculous temperatures in Jersey would be a very warm airmass. I'd expect uppers in the low twenties necessary.

That has 'always' been the forecast for today though.

Always been quite skeptical of it. Not so much now.

I just don't get how a relatively mediocre airmass can produce these exceptional temperatures. Temperatures arn't even that exceptional across France so even low level WAA doesn't quite explain it.

Must have something to do with soil moisture and the dry spring. Must do, otherwise this kind of thing would be alot more common.

Here are the current soil moisture levels - quite low in parts of the south-east. A wide range across the country.

http://wxmaps.org/pix/soil4

What's strange is that the models seem to have moderated the airmass even more. We barely get to 18C at 850mb through the afternoon now.

Nick - I can see the same line of cloud out to the west. It's visible on the Blackbushe webcam, which looks in the same direction as my window does, from only a mile or so away. https://www.blackbusheairport.co.uk/weather/

Looking at the radar those must be the showers that are around Bristol. I know from looking at plane trackers that I can see planes (or at least their sunlit contrails!) at 35,000ft up to 200 miles away out of my window (over mid Wales) so would be easy to see tall shower clouds there.

There are some hefty showers forming and moving NE in the SW channel. This could cap the late afternoon max temperatures.

My station reading 29.6 right now.

A very large cloud mass there which will probably head into central southern England this afternoon (as forecast). Highest temperatures will definitely be further east. Already that cloud is impacting the Channel Isles. Jersey on the eastern fringes of it.

https://meteoradar.co.uk/clouds-sun-UK-Ireland

I've just looked at the Satellite. Looks like a large mass of cloud heading towards the Channel Islands. Could it central southern England later.

Its never simple is it.  

I thought we were forecast pretty much uninterrupted sunshine until the evening. Certainly not looking that way on the satellite image. I can't see how we will get close to a record with that lot heading our way.

Its full of rain as well 

If you watched the BBC forecasts on TV last night there was a lot of cloud forecast across central southern England this afternoon with a few embedded showers. It was absolutely forecast.

I have worked out what is happening with the hourly Heathrow temperatures on the Weathercast site. Initially they are showing the XX50 METAR reading and then once the XX00 Met Office station reading becomes available they replace the METAR reading. The METARs are always shown to the nearest whole degree. So the 29.0C showing for 1100 will be updated shortly (unless the Met Office site also happened to be reading 29.0C at 1100).

Kenley 29.7C @1100

EDIT  - Heathrow figure now updated to 29.4C

I'd like us to be on 31C by at least midday.

I feel things are fraught with danger today

These hot temperatures suck... you really don't want them if you're at work or in a house without a/c!

Meanwhile as of 11 AM we have Heathrow and Gatwick reporting 29, with Calais on 32.

It's a combination of the dry soil (even drier in Spain and France) and the interaction of the wind flow with topography. Just look how the highest temps will be south/southwest of the Downs this weekend when the low level flow changes.

30.4C Jersey Maison St Louis @1105

Working in the garden all morning and it's absolutely beautiful. I think I'll have a cocktail instead of lunch.

LOL - My fruit ciders in the fridge are getting more tempting by the minute.