The 12z GFS and NMM seemed to have a lot of trouble with initiating the overnight convection in an organised fashion - a messy result with a lack of intense cores to the cells.

A different story for tomorrow evening from NMM, with some intense rain crossing CS England. One of countless possible outcomes... EURO4 runs a similar feature across CS in the afternoon and then follows it up with another such feature that runs up the eastern side of the UK from south to north - caught up in the flow around the Scandi High as opposed to the low coming up from France.

Euro4 is among the closest models to what the radar currently shows... it's just 2 or 3 hours behind on the schedule!

Certainly some signs that the storms may arrange themselves such as to bring a succession of downpours to some parts while others escape with a lot less: http://www.metoffice.gov.uk/public/weather/observation/rainfall-radar#?map=Rainfall&fcTime=1439371800&zoom=7&lon=-2.89&lat=50.00

That area SW of the IOW was a bit to keen to get here - it's run ahead of the moisture plume and found itself in a drier, more stable environment. In theory, the storms just leaving France won't encounter such a fate until they've tracked up into The Midlands.

Based on Euro4, the area of little precipitation between the western and eastern clusters ought to fill in with some similarly intense storms, while the activity as a whole takes on more of a NW movement by around 6am tomorrow. The model does then show the early morning storms decaying rapidly once beyond the South Coast, but this is often done too rapidly, which is reflected by the fact that the BBC/Met Office forecasts this evening have shown them remaining very intense until as far inland as Oxford.

As usual, the phrase 'hit and miss' has to be emphasised, along with the general uncertainty regarding storm timing and intensity.

Will the storms stay in the channel or move inland, bets on a post card

http://prntscr.com/83yhg0 

Pity http://www.estofex.org/ are sleeping be good to see their take on the situation.   

25 mm rain so far here since about 3am  thunder and lightning for about 3 hours

It's either a dreadful forecast or there is another batch on it's way? 

GFS0z 5 day accumulated precip chart:

Its totally wrong so far. We were supposed to be deluged from the early hours. Ferguson on Twitter admitting high res models have been "OTT" on this so far. 

Still looks nasty toward the south coast, and as others have already stated, these are a nightmare to forecast

Dutton mentioned issues with high res models earlier this year on Twitter. Makes you wonder whether the focus on finer and finer grids shouldn't be given priority over more comprehensive initiation data.

It seem the models had been very wrong as well as look how high the temps over the channel and how it can reach with the rain all around?

http://www.wetterzentrale.de/pics/Rhgfs184.gif

Also cannot see it coming off on those high 20's here today as there no sun- no warmth.

Bit of a dry squib here 

Interesting although I guess it doesn't/cannot pin down details of convective precipitation. Looks stupidly wet here tomorrow though - hopefully that is wrong too (or models will change before then)

Looking at the radar and satellite imagery and animation if I was in the south I would be keeping a close eye on what may be coming up from the south in the coming hours. 

http://www.sat24.com

It may be hit and miss but I suspect a few locations may be "hit".

It tries to but I agree it doesn't do it very well. 

The ridge is putting up more of a fight than expected... in fact the low seems to have ended up drifting a bit further east than anticipated as well.

The plume of very high moisture is only now starting to creep into the SE. Even there, it's only the northern edge that possesses any particularly impressive rainfall rates. Make no mistake - the moisture aloft is sufficient for 60-80mm in places today, but without the convection, it may as well be dry up there!

In the short term, it appears that proper thunderstorm type conditions will be restricted to areas east of Brighton or thereabouts, while The Solent and areas a little way NW of there may experience 'thundery rain' which looks heavy but generally falling short of torrential. It could turn out to be quite prolonged though, if the low and plume keep up this sluggish behaviour.

Through the afternoon, I suppose a few embedded cells are possible more generally across S. England, based on that mass just leaving France (east of the peninsula), but with so much change in steering over the past 6 hours, I'm not feeling bold enough to predict where exactly that will end up going!

Any notable breaks in the cloud are on the far side of that thing so probably out of reach for Southern England I'm afraid. A few breaks between the masses in The Channel could allow temps to reach into the low 20's though. Still an outside chance of 25*C or more based on GFS (which has 27*C IMBY... dream on!).

true thundery rain over Portsmouth this morning, heavy rain with occasional thunder. 

Moderately heavy rain here at this time, occasional thunder.

Radio Sussex reporting minor flooding in places between Brighton and Eastbourne

The 10.30 radar frame is looking quite impressive, if it makes landfall. It is heading NNW at present.

Brighton webcams.

http://www.theargus.co.uk/news/i360_brighton/

http://www.drakesofbrighton.com/live-beach-cam.html

Looking fairly moist.

Going by net radar I think SE England is going to cop it later on.

The Euro4 model looking interesting for tonight and tomorrow to if its to be believed.