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Personally I feel this is being over hyped. For a majority this will be nothing more than a spell of heavy rain and a strong breeze. Obviously some locations may see more in the way of severe weather but these will be the exceptions.

Good morning fellow SE/EA folks. Yesterday was a day that will live in my memory for quite a while. My wife and I had agreed to drive up to Huntingdon yesterday afternoon to meet my son, girlfriend and their little boy after my son left work for the day. We left home at about 14.15 to sunny intervals and a temperature of about 23C according to my car thermometer, although it felt a lot hotter than that, as well as sticky and uncomfortable due no doubt to the high humidity. By the time we were passing by the village of Takeley it had started to drizzle and when we had reached the large roundabout at Stansted it was sheeting it down in biblical proportions. It was so heavy that I considered it to be too dangerous to progress onto the M11 and so we made for the Birchanger Services just off the roundabout along with many other motorists. Having parked there for about 20 minutes until the deluge relented a little I then had to queue up for some time to exit onto the roundabout as everyone else had the same idea! The M11 was very slow from the moment we joined and was at gridlock by the time we reached Cambridge. By this time the rain had intensified again and I decided to leave at Junction 13 as I know a route when one can join the M11/A14 junction near the crematorium later. We stopped in a Cambridge side road for about 10 minutes as it was difficult to see the road ahead as it was raining so heavily. On rejoining the main route the traffic was still heavy for some miles but gradually thinned out after the Biggleswade exit. Water was however pouring off the fields onto the inside lane of the motorway. When we arrived at the first exit for Huntingdon (80's Weather will know where I mean) taking the road to Godmanchester and at the traffic calming measure that narrows the road by the allotments we had to queue for some time as drivers approached what must have been about 2 feet of floodwater. The rest of the journey was fairly straightforward but instead of taking about 75 minutes on a good day it took about 3 hours 20 minutes. Our return journey home was not as bad, although we encountered torrential rain for the vast majority of the journey and the road into Godmanchester had remained flooded. We did note that even at after 10 in the evening there was still a queue of traffic northbound in the vicinity of Cambridge for several miles. Kind regards Dave

As much as I believe many of us here on nw are particularly interested in severe weather, I for one would be happy to see the UK escape the worst of it, coming as it does at the weekend in the peak holiday season. A lot of families will be out and about, many of them on their annual holidays and a fair percentage of them will be down in the West Country. I had the misfortune to be on a camping holiday in that part of the country with my very young family when the Fastnet storm hit in August 1979. It was horrendous and completely wrecked what was our only holiday in years. I wouldn't wish that on anyone.

Well I'm back again It has got busy with over 150 users looking on this topic. This will be a long one but I have the link to it. http://www.weatherscientific.co.uk/2014/08/09/sunday-10th-august-red-warning-for-severe-thunderstorms-20-for-england-wales/ A combination of an extremely warm and moist airmass associated with the tropical remnants of ex-hurricane Bertha, rapidly and intense cooling aloft occurring during the rapid cyclogenesis of the storm, numerous complex vorticity eddies tied in the intense low pressure and a very strong jet-stream will all come together to bring a significant risk of severe or locally extreme weather conditions. There is a few possibilities, one is a forced line of convection/squall type feature that will move readily East during the morning and early afternoon across England and Wales. Due to the tropical airmass very warm and moist air and the dynamic forcing of the cold front will be the focus for some especially intense thunderstorms. CAPE in the region of 750j/KG to 1000j/KG will be possible with very strong DLS in the order of 40/50kts and SRH in the order of 300-400m2/s2 – these values are augmented by a strong jet-streak tied into the left exit region of the jet. These very high values of wind-shear and helicity do appear to overlap with instability and combined with a very volatile environment several intense severe thunderstorm episodes are possible. Current thinking is that a squall line is possible but this is dependant on the phasing of the system, nevertheless convection seems incredibly likely given the overall dynamics and storms that do evolve during Berthas passage will become severe rapidly with the possibility of mesocyclones and the additional threat of one or two strong tornado events. It must be stressed that should a tornado evolve in this environment it could become long track. Perhaps the main threat with storms will be the wind gust potential helped along by an extremely vigorous 850mb flow and backed up by a strong 500mb upper flow and on current tracking some particularly severe wind gusts are possible along the South Coast and across South West England, The Midlands, Dorset, Somerset, and parts of South Wales. There is the potential of damaging wind gusts of 50-60mph or even upwards of 70mph in the most severe convection. A Severe 20% was issued for areas of highest instability and wind-shear, but all parts of England and Wales should be alert to the risk of severe convection that has high potential to bring disruption and dangerous conditions. * Further note should be made that the environment within Bertha will be extremely unstable and there is the very real threat of supercell development and the obvious severe threats these bring. Main threats are large hail, damaging winds, frequent lightning and tornadoes. A tornado watch with potential for a warning has been put in place with the added risk of an isolated long track strong tornado. This is the most extreme case of severe convection we have seen this year and as this is all developing within a tropical airmass it is a situation that needs to be taken seriously. Make no mistake, Sunday Morning is going to be significant for some. To give some insight into the potential severity of this event it could well be classified as a high-end level 2 Estofex or even a low-end level 3.

No disrespect intended to anyone but I'm pretty confident that the full time paid professionals at the Met Office with all data at their fingertips are in a far better position to call this, as opposed to a few of us amateurs on an internet website ?

Yesterdays storms produced what looks like a possible tornado up here in the North. Around 3pm Andrew Cogan caught a possible tornado as it brushed through Haltwhistle, a small town along the A69 between Carlisle and Newcastle.

BB54, have you become bitter in some way? It would be a shame if you are unable to spend less time sniping rather than enjoying the craic. So, big hugy tail thing will arrive here in about 7 hours. 16.5C, still, dark.

Analysis of the met-office or any other organisations should be surely debated after the event, not before Bertha has even arrived. Please keep things civil in here, thankyou

Still no real visible circulation to ex bertha, so the models are still likely to be up in the air. Looking at the current model outputs there are a few things to consider. First set of charts come curtesy of lightning wizard based on GFS output. This shows there is some residual moisture at the surface after the cold front has moved through. NMM suggests a possibility of some postal frontal storms. Notice that the dry air does not really wrap into the system, probably meaning that the energy is not there for a bent back occlusion and a sting jet as the system crosses the UK. This could be a bit of an unstable environment. Looking at satellite pictures I think we are likely to get a significant warm sector shield, but there might be an oppotunity for some line convection on th back edge of the cold front. We should also not ignore the triple point if it crosses the UK as this may have a wind field suitable for the formation of a mesocyclone. One final chart which should be taken with a large pinch of salt. Personally I am not sure the system is going to play ball the way models predict and there is a big risk it will all come to nothing. So its still way to early to predict. Biggest risks are still from heavy rainfall and localised flooding. Depending on how things develop there is potential for a severe thunderstorm although tops look a little low, and cloud cover will play a part. Potential for some more covective activity in western areas late on as well.

Just had to delete a post, Can we please only discuss Model Output in here. There are other threads for "I told you so's" and Weather gambling.. Many Thanks. PM

it's the met (office) police Neil....they're coming to getcha!

The exact track of Bertha seems to look better now than this time yesterday. Below I have made up another quick map that shows the track of it using the GFS, ECM and UKMO. They seem to agree on it passing over the same area and the deepness is expected to be around 990mb which most of the models show although some do have it a bit deeper. Using the latest GFS 06z run here's what it says is meant to happen, Sunday 12am to 6am - Bertha approaches the UK from the South West it makes land fall over the South West of England and Southern Wales. Wind gusts of 35 to 45mph are possible with exposed parts seeing gusts of 55mph or slightly more. Very heavy rain moves in as well over this area. 6am to 12pm - The low is now over the Midlands, gusts inland across England and Wales ranges from 30 to 40mph and exposed parts could see up to 50mph. The rain becomes more widespread covering Northern parts of England and the Eastern parts as well. 12pm to 6pm - The low passes over Northern England which brings strong winds there gusts around 40 to 50mph and on exposed parts along the Eastern coasts 60mph is possible. The rain over Wales and England starts to dry up but Northern England and Scotland see the rain at this time now.

Looks like a feasible run to me. The working week will be much cooler and windier than what we've been used to, conditions best in the S. By Fri it will start to settle down and slowly warm up, next weekend doesn't look too bad, especially for the S, surface temps look to be average. Hopefully not too much infill to ruin things. Think the major difference next week will be nighttime temps...a chill in the air! Should be better for sleeping anyway.

This looks a bit like the Azores high to me?

21 days left of August left, I'd say there is still time for something decent to crop up. What is that low in the Atlantic going to do? It does look like the Azores high could ridge in to bring better weather next weekend. That low needs watching as its movement could swing where we head in week 2. UKMO looks the most positive about a pressure build next weekend with the high in place even by Friday. The others are slower and less effective.

I take it you are talking about Bertha and you haven't just ordered a new family pet? :unknw:The big huggey tail thing looks like it will give London some more much needed rain, could do without the wind though! Hopefully it won't be anything like the storms we saw last winter! I can see the spot light too!

Are the bats eating the dogs?

Here goes! first time using this forum and I must admit to not really knowing all the technical terms for weather so you will have to excuse me when I use very basic common terms to describe things I live on the border of Derbyshire and Nottinghamshire and have for the past hour been watching some very black and heavy clouds roll in, have had a few heavy sharp showers but lasting no more then a minute or two. Just looking at how angry the skies are at the minute and you can tell it is just waiting to unleash its fury. Is the the front to Ex Bertha ?

I was just going to comment on how the GFS seems keen to spread some pretty vicious thunderstorms NE tomorrow but not sure how much reliance can be put on it. Essentially it shows CAPE in the region of 1000j/kg interacting with the jet stream creating deep layer shear, low layer shear, helicity. This and increased lapse rates all look to be developing together in an area from SW England and South Wales through the Midlands and exiting out into the North Sea. This would translate to a fairly good chance of supercell development accompanied by frequent lightning, large hail up to 3cm in diameter, strong wind gusts and maybe the odd tornado report. Timing would bring it into the SW early hours of the morning and then exiting the North Sea late afternoon. I am not very experienced at this kind of scenario so, like you, my brain is hurting. I will await a more experienced view.

On the contrary we get ex hurricane remnants quite often in August, not every year but regularly.

Really? Not sure the wind warrants a warning here, rain perhaps.

Here she comes, courtesy of the MODIS on Terra. http://lance-modis.eosdis.nasa.gov/imagery/subsets/?subset=Europe_2_01.2014221.terra.1km Taken around 12:30 today

Not on about 30c heat just decent 23c plus stuff will be fine Not a hopecast very likely to happen even in September and in any event I shall get as much pleasure from wet and windy as warm and sunny (as a rain nut)!

Unlikely, as sting jets tends to occur with rapid cyclogenesis of lows that are associated with confluent troughs where there are rapid pressure rises causing a tight pressure gradient. RACY rarely occurs this time of year and besides, this low is slow deepener in a diffluent trough. Still going to be rather windy for early Aug though!

After an unsettled spell things slowly calm down from Thursday looking at the ecm ens though it will still be cooler than we've become use to with a northwesterly flow Friday is a similar picture though pressure continues to rise from the south west During next weekend and into the following week the move to higher pressure continues with winds slowly moving round to a westerly allowing warmer air to move back in

GFS and ECMWF operationals still sticking to their guns, UKMO fax still in between. Not often you see such a gap in tracks at t+36 hours out. Just goes to show the difficulties NWP has at simulating lows with ex-tropical storm energy in their make-up and whether or not the low phases favourably with upper trough catching it up from the west and whether or not it falls under the jet left exit on the cold side of the jet to deepen and move NE rather than track east as a shallow feature.

After the GEM op was going against its control and majority ensemble consensus the op has now come in line: JMA is similar with track and intensity as it travels NE: Navgem who has followed ECM blindly now has the GFS route: The hi res models show the potential for strong gusts tracking just south of Bertha centre: Still differences though: And where GFS has the worse rain in the Midlands, ECM has it as the driest: GFS for the next 5-7 days looks like cooler temps with the uppers 3-4c below average for London: The op and control are unsettled with no sustained higher pressure; tentative signs of next weekend settling down for the far south. But the end are in good agreement and the D10 mean reflects this: ECM at D8 looks more promising but bearing in mind they are the only model going for a different track on Bertha anything that follows is debatable: Unless of course they are right. Though ECM did not spot typhoon Rammasun till the morning it hit the Philippines whereas GFS had tracked it for over a week. In fact GFS spotted Bertha on 28th July and its timing was only about a day out even at that range:

LOL! Ruin your carpet!

Probably a soaking wet loon by now

Another update in my blog after digesting the 12z output: http://www.netweather.tv/index.cgi?action=news;storyid=6068;sess= 2100 update 08/08/2014 Still the models disagree less than 48 hours away from when the centre of the depression formed from ex-Bertha makes landfall somewhere across the west of mainland UK on Sunday morning. 12z GFS takes the centre of the low up through the Irish Sea on Sunday morning and makes landfall across Cumbria around lunchtime before exiting over SE Scotland into the North Sea, the centre on land crossing circa 985mb, so fairly deep for the time of year. It shows wind gusts of 40-60mph over coasts and hills of SW England, Wales and northern England - perhaps more on the lee side of the Pennines and mountains of N Wales, plus funnel effect of valleys. 30-40mph gusts further south and east. Rainfall totals of 50mm+ across southern Ireland, 20-30mm max across Wales and N England. ECMWF, on the other hand, takes the low centre, a shallower feature, NE across S England, exiting The Wash into the N Sea around 995mb. Winds and rainfall totals less, but still appreciable to make Sunday a windy wash out across much of England and Wales. Met Office T+48 fax chart for noon Sunday is in between ECM and GFS tracks but closer to the ECM depth with 996mb, so perhaps this maybe the best compromise for the likely track for now. GFS indicates a convective element to this storm system, with instability and strong wind shear in the warm sector just ahead of the cold front sweeping east - so there is a risk of organised embedded storms, perhaps supercells, which could produce their own severe weather in the form of strong convective gusts, large hail and even a tornado or two ... I will look into this scenario in a storm forecast to be issued nearer the time.

Thunder and lightning for pretty much 6 hours. Crazy. Saw one last distant flash as I left Tesco recently.

Some pretty bad quality lightning stills, the last one is from a CG, couldnt manage to get the bolt when pausing the video.

Best guess.

After reading the most recent posts and seeing the latest models, I'm not feeling that great about tomorrow. I could probably reach 35 mph at best which before I thought nearly 50 mph. Anyway, no more looking on the charts now and I'm just going to see what happens. Good luck everyone.

I think this about sums up my thoughts Mapantz. Troublesome given that it's a weekend in the peak holiday season, which is why I think the Met Office warnings to be aware are pretty much spot on so far.

We need to be wary of more typical summer developments, so perhaps embedded thunderstorms or a squall line could develop which could bring torrential rain, hail and strong gusts of wind. This is probably the main issue with this system.

A few snippets of the torrential downpour i chased yesterday in North Nottinghamshire. https://www.youtube.com/watch?v=gJhPf8KSDuA&list=UUQQOWmfgDDRfs90xgDAyN9Q The clouds at the end of the video as the system passed over were rather impressive, the whole sky was filled with it.

Did Nick F not answer the question on the previous page the best that it can be answered considering the uncertainty of the exact track of ex-Bertha?

In terms of appreciable heat, time is fast running out. Only James Madden is continuing to suggest 30C by months end is still on the cards. Those that want to bang the drums of heat based on nothing more than hope - then by all means, enjoy! GEFS temp anom days 0-16 0z

You can get the ECM in 3 hour periods here http://www.yr.no/kart/#lat=54.95086&lon=-2.21135&zoom=6&laga=trykk&proj=900913

Hi Cleeve...you can also use this link http://www.yr.no/satellitt/europa_animasjon.html Nick, Is there a possibility this storm could produce a `sting jet` ?

I must say the models have still not pinned down the track or the power of it yet. I think we know when the storm is near us. And it could be stronger then forecast.

It's nice to see the models flipping around as much in summer as they do in winter. Makes one look forward to the winter! Anyway, IMHO, the ECM is not the right model for looking at forecasts as we come into the 36 hour period. The ECM is strongest from about four days out; glancing at the charts in summer with rather less regularity than in winter, it occurs to me that the ECM did pick up a rapidly deepening low about a week or so ago which was largely written off by most (understandably as such deep systems are fairly rare at this time of year). IIRC, the system was shown to be about 996mb off the coast of Cornwall, whereas the GFS at the same distance showed nothing of the sort. Since then the GFS has gone for the deeper system whereas the ECM operational shows a shallower feature tracking further south. At this range I don't really trust either and pay much more attention to the FAX, being a blend of several models plus hi-res output, and the other available hi-res models. Having said that, the NMM was off target for yesterday, showing heaving rain mainly affecting Kent, Sussex and parts of East Anglia whereas in reality we had something of a deluge in Reading. So, I'm sticking pretty much with met office guidance on this one which is not to say that the models aren't interesting in terms of spot the difference, but the detail is lacking, particularly in the ECM where only 24 hour time periods are shown.

just to give members an idea of the amount of rainfall that's been falling this evening, here's the rainfall accumulations for the past 6 hours.....some parts of the region have already had around an inch of rain with more to come for those to the east of London...

Jake called them!

Goodness me, some quite heavy rain just now and the wind has suddenly increased very noticeably. Still as muggy as all get out though.

We're still bashing the old meto/beeb over here are we? I'd hoped you'd all managed to grow up! wishful thinking eh? Meanwhile... Very wet out there, lots of surface flooding in the way back from Hatfield.

I've just seen the bbc weather and it seems the low looks slightly further south than gfs seems to want to take it. To my poorly sighted eyes it seems to take the low along the channel then out through south east in North Sea then up north....winds didn't seem all that bad, barely any gales really, just very breezy, rain seems to be the main issue....we'll see what tomorrow brings

I emailed the BOM and asked whether the recent Australian coldwave was significant enough for them to release a Special Climate Statement, which is issued whenever a historical significant weather events takes place. The Special Climate Statement page: http://www.bom.gov.au/climate/current/statements/ I got a quick reply which was nice of them: Fair enough.

I detect the beginnings of the ol' north v south argument when it comes to storms. Please don't start that nonsense here.