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After a remarkably warm/hot few days it looks like the first proper thundery spell of the season is upon some of us for tomorrow. As low pressure moves in from the west it combines with a plume of warm, humid air from the south to bring the risk of thunderstorms. It is still too early to get a true grasp on exactly where the storms will be as models are not in total agreement but Saturday will start dry and sunny. Temperatures are likely to rise into the high teens or low 20's across most of England and Wales with dew points also increasing and so it will start to feel more humid. Most models are showing the general idea of the first showers and thunderstorms developing across the SW at some point tomorrow morning before pushing them NNE through Wales, the Midlands and up into the North of England through the afternoon and evening. CAPE values in the region of 500-1000j/kg (dependent on which model you look at) would indicate that storms have the potential to produce frequent lightning and 1-2cm hail. Some are then picking up on a second round of storms moving into the south coast through the evening and across the south-east quadrant of the UK overnight. ECM seem very keen on this idea. There is doubt as to how much of the UK these will affect, with areas to the south-east most at risk I would say. These are likely to be elevated in nature but with some exceptional CAPE values for this time of year they would again bring the risk of frequent lightning and hail of 2-3cm. GFS storm risk for 6pm and then midnight NMM CAPE values for 6pm and midnight (this is MUCAPE and so combines both surface based and elevated CAPE) On the downside, deep layer shear is not great tomorrow, but with high levels of CAPE it is still possible there could be some more organised storms that develop and push NE through the course of tomorrow afternoon, evening and night. Regardless, any storms that do occur will produce torrential rainfall with a risk of localised flooding and possibly also gusty winds. So it seems there is some consensus on there being two main rounds of thunderstorms. Round one will start of in the SW and move NNE to affect parts of Wales and the Midlands and then N England through the afternoon and evening. Round two will move into the south coast during the evening and move NE to affect SE parts. The question is where these storms will track, as some places will inevitably miss out where others get a very decent storm. It is also feasible that storms develop more widely as some of the models have storm activity exploding into life tomorrow evening and night as low pressure and associated cool air from the west moves over the top of the warm plume that will be in place across England and Wales by this point. All in all a very exciting 36-48 hours (or more as a further risk of storms looks likely across East Anglia and the far SE on Sunday afternoon/evening). NMM extent of convective precipitation by midnight and NMM precipitation rates at 4pm, 9pm and then midnight. All subject to changes of course, it is very difficult to pinpoint the exact location of storms even at 3-6 hours ahead but a general idea can at least be attained. I am going to be interested to hear the thoughts of the experts/storm forecasting sites this evening

Morning all First, kudos to those who called the heat correctly. I didn't think it would get past 25c in London let alone to near 29c and for all this we can think the SSW and the Beast from the East. A moment - northern blocking and, more importantly, the trough to the south of the British Isles or over Europe meant warm air funnelled from Africa up over Eastern Europe so the Balkans got an early spring with 22c in Belgrade as early as March 12th. When the set up returned over Easter another warm plume moved up over south eastern and eastern Europe (24c in Belgrade on March 30th). That meant when the synoptics enabled sir to be sourced from the SE said air was unusually warm and with the minimum fetch over the cool North Sea and aided by the strengthening sunshine, we got the record temperatures we have seen. Without the modification of the Atlantic, more continental-type climactic events are possible and in many of these the transition from winter to spring can, in temperature terms, be rapid. Look at what happens in North America and Siberia as winter eases - huge contrasts in temperature can be experienced even on a daily basis. Worth thinking about IF the Atlantic becomes less influential in our weather and climate. Back then to the models and some thoughts on where we will be at the end of the month based on the morning output so it's Monday April 30th and starting with ECM 00Z at T+240: Back to a more normal pattern from next week with our weather coming off the Atlantic. LP to the NW and HP to the SW and by T+240 a broad ridge from the (slightly displaced) Azores HP hints at decent conditions for most while LP is gathering to the west of Iceland and may become more influential as May starts. GEM 00Z at the same time: A more unsettled evolution. GEM re-orients the Azores HP more to the west and north and that allows the trough to drop SE over the British isles so we end up in a very unsettled pattern with slow-moving LP bringing plenty of rain or showers. GFS 00Z OP at T+240: Once again GFS teases with an E'ly but it wouldn't take much for the GEM evolution to reach a similar point or even the ECM evolution. GFS has LP to the south west and heights build to the NW from the Azores using the "up and over" approach with the ridge inclining toward Scandinavia. A warm pattern given the air source with showers or perhaps storms for the south but fine further north. Further into FI the easterly pattern continues for southern and eastern parts but then shifts to a NE'ly and introduces a brief much colder air flow. GFS 00Z Control at the same time: A chilly northerly as the trough edges east and heights try to build in from the west. A more progressive version of the GEM evolution in my view. Further into FI, however, things turn much drier and warmer as a large HP builds over Scandinavia and ridges back SW across southern parts. The GEFS for 00Z at T+240: http://www.meteociel.fr/cartes_obs/gens_panel.php?modele=0&mode=1&ech=240 A really mixed bag. Fans of heat can go straight to P10 which would rival if not surpass the current warm spell while fans of cold can go to P11 for their daily fix and while there doesn't appear to be a lot of spread the truth is for our tiny island slight changes in position and orientation of large weather systems can have huge impacts. The only trend I see is no trend. Mean puts LP close by and that's well supported and you can't go far wrong with that as a forecast but I'm struggling to see a clear message even at this range. In summary, the fine spell is a memory by Monday and next week looks to be more "normal" with a westerly pattern off the Atlantic. From there, the evolutions are varied - both GEM and GFS push LP close to the British Isles, the former has it over us and the latter to the south pulling in a prolonged spell of easterly winds. ECM keeps heights closer but you wonder if the trough at T+240 might not swing SE from its position west of Iceland.

Storm & Convective Forecast Issued 2018-04-20 22:07:48 Valid: 21/04/2018 6am TO 22/04/2018 6am THUNDERSTORM OUTLOOK - DAY 1 (SATURDAY 21ST APRIL) Synopsis An upper trough moving across the Atlantic will arrive across the far west of the British Isles on Saturday, as upper level high on near continent retreats. A surface low will drift NE to the south of Iceland beneath the upper trough arriving to the west. Backing of the flow to a Sly direction across England and Wales on Saturday will draw in an increasingly warm and moist but unstable airmass out of France, with an increasing risk of thunderstorms developing northeastwards across England and Wales during the forecast period. … ENGLAND and WALES … * Risk of ... hail (isolated large) strong wind gusts flash-flooding frequent cloud-to-ground lightning Plume of warm moist air, characterised by high wet bulb potential temps (WBPT), will advance across S England and Wales Saturday morning, a shortwave trough moving up from NW France looks to destabilise this plume and support the development of thundery showers and increasingly a risk of elevated thunderstorms moving N/NE, initially isolated across SW and S central England in the morning, then more widely across Wales, Midlands and parts of N England into the afternoon, as mid-level temperatures continue to cool aloft from the west, steepening lapse rates. These elevated storms may bring some hail, frequent lightning and localised flooding. Although there will be some capping of the surface airmass by the Elevated Mixed Layer of the plume, surface heating combined with orographic forcing and/or breeze convergence may allow the cap to be overcome to allow some surface-based thunderstorms to develop where skies clear – particularly over north Wales, north Midlands and northern England. Any surface based storm that develops could tap into 500-900 j/kg CAPE – which could allow some isolated large hail, torrential rain leading to flash-flooding, frequent CG lightning and strong winds gusts … the weak vertical shear (20-30knts between 0-6km) will limit severe potential, so will abstain from delineating a severe risk area. During the evening, increasing large scale ascent and cooling aloft from approaching Atlantic trough from the west interacting with WBPT plume advecting north is forecast by a number of models to form a wave of elevated storms developing over the English Channel / N France initially before spreading northeast across parts of S and SE England along with E Anglia in the evening and overnight. Also ongoing storms further north over the Midlands and N England for a time, before clearing NE in the night. These elevated storms may produce hail, strong wind gusts, localised flooding and frequent cloud-to-ground lightning. Issued by: Nick Finnis https://www.netweather.tv/weather-forecasts/uk/convective

Quite astonishing and something I rarely see on hi-res models. The Netweather NMM model 12z, caught my eye as a small area of Wales witness significantly lower temperatures than the near surrounding area of which this area moves north over time. Check this chart out for tomorrow at 3pm. This really could only mean one thing... SOMETHING must be causing this; some extremely heavy precipitation. After looking at the following CAPE chart, it was obvious a large area of violent thunderstorms must have formed. If this is to happen, then I would expect some extremely violent and well structured multi-cell/squall like feature to form and move northeastwards tomorrow. Interesting times!

Looking forward to the chance of storms tomorrow evening. Already warned the husband if I become unbearable lol! I’ll spending the day at the brooklands museum in the sunny weather, an evening storm to top it off would be perfect. Better manage expectations though.

Great to see ECM going for another spell of settled weather to develop later next week

Hmmm methinks it’s another case of a long build up to a non-event with lots of teasing along the way. Too many times the high pressure is just too dominant and there isn’t enough surface warming once the morning cloud (and potential fog?!) clears. Will keep an eye toward wales and the west just in case but it’s looking like it’s all being downgraded to nothing. First disappointing plume setup of the year? ...Perhaps! But wait! My eye is drawn to the overnight potential in the SE regions which looks more possible given the synoptics currently being offered. We will see tomorrow! The wait continues...

Aye to quote Damis favourite band ,it's a CIN ........

We broke a temp record, did anyone break the record for most burnt sausages at a single bbq

what the flog although i've just sowed all my seeds and i am now seedless as i thought winter was over

Foul! We’ve had plenty of cold, any cold now just causes damage to fruit and vegetables, hopefully it won’t be as bad as shown ?

Things could go bang during tomorrow as some thunderstorms move up the country

My neck of the woods 2018 has been a memorable year for weather so far recent few years nothing really stands out. What we need now is prolonged warm summer although I’m doubtful, MCS not grazing the far SE when was the last time we were all hit! A terrific gale by bonfire night & snow by Christmas. Dear Santa, ahem..

Exactly frosty....the mean just indicates average temps. 850s of 0-5c are easily double digits this time of year. You’d need sub -10 air now to get something cold and wintry....let’s leave it for 6 months and try again.

It’s lovely ! Sitting in garden ( solar lights on) coffee ... stars , moon ...and music in my ears ! Have a wonderful summer everyone xx just to clarify the stars and moon are not in my ear

Here’s Convective Weather’s risk map for tomorrow. They got the last few storm risks correct.

Indeed it was more humid. I don't know if anyone else has commented on this but yesterday the humidity was only around 35% according to the Heathrow METAR yesterday. Thats quite unusual as far as a can see from my very amateur observations. I shall be glued to the radar from about 3 pm onwards tomorrow. To reduce the stress i have made some changes for myself this summer. 1. I wont be looking at every single GFS run leading up to a possible event. I realise i don't have enough knowledge to be able to discern anything myself anyway and I'll leave it up to those with more expertise. 2. Im going to unfollow twitter and facebook pages that hype up events and promise supercells in every damn forecast!

HP laptops

Is data glitch the new name for HP supercells mumspantz ??

I think places further east were indeed warmer today, maybe there was less of an easterly blowing, it was quite windy here late afternoon yesterday but hardly a breeze tonight. Some coastal areas have stayed cool though just like yesterday.

With the consensus next week for a zonal westerly flow, it's interesting to look a little further ahead. GFS, GEM and ECM at T240: These show quite different weather, but a more amplified jet stream is in evidence across the models. Increases the possibility in my opinion of the weather blowing hot and cold during late April and early May. Maybe something for everyone.

Currently a very pleasant 20.1c here in St Leonards-on-Sea at 19:30 bst. Down at the beach earlier this afternoon it felt even warmer than yesterday and interesting to note that nearby Herstmonceux recorded 22.4c yesterday and 25.1c today.

If it’s going to be that hot not extremely unusual, think it reached that in 2015 and 2016 here, then for the thing of it I want to see 40C attempted at not happened but it’s not impossible. I do not enjoy them particularly high temperatures I can be fairly OK with the low 30s permitting humidity isn’t high, the only appeal to me is statistical significance. Another wonderful summery day I like early season ‘heat’ more fresh shame it’s not going to last too good to.

Lol roll on much more sunshine and storms so lassie can get his burgers and baps going on the bbq! Hoping to see at least 1 36c day this summer!

I been in Greenwich, lovely day out but I kept seeing sausages everywhere I looked, thought I was going completely potty, anyway took some pics just to prove I ain't seeing things.

Will be interesting to see UKMO t168 - t144 isn't far away for a window of settled weather later next week

So... has anyone seen Convective Weather's forecast for tomorrow?

Well just look at what 06z is showing for next weeks Mayday bank holiday. Frost and even Snow in places mainly in the north but you never know....

You'd be hard pushed to call 12c "winter".

Like it or not, that is the normal UK climate. Funny you mention miami though; I have holidayed in florida in the peak of their "summer" (theme parks were worth it) and the level of humidity is excruciating. Any "warmth" we get is usually sourced from Iberia and laced with humidity also. simply serves to rub salt in the wound, nothing more.

I live in a city that has one of the highest air pollution levels in Western Europe, and one of the top 3 in the UK. Dangerous air quality isn't unique to London. And it was 27C today, only 2C cooler than London, and I thought it was absolutely lovely. No complaints from me at all. And air quality has little to do with heat - on clear, calm, frosty winter mornings, you will often see a brown haze sitting over Leeds. Some people on here don't half talk rubbish sometimes. We get it - you don't like heat. No need to witter on about it like a broken record. The rest of us have had to put up with months of cool, wet weather so forgive me if I have no sympathy for your plight. In fact, if you hate heat then few countries in the world are better than the UK. By global standards, London's summers are cool and cloudy. Even by European standards they are very lacklustre - yet the way some people on here go on about them you'd think London was the new Miami or something.

Had one just like that in may last year here, never seen anything like it. Had a couple of decent storms before it arrived too. In fact went down stairs for a cupper, was think about going to sleep after the second one, as couldn't see anything else approaching. When I went back upstairs, all I could see was constant strobe flashing, think it was still in France then, started to see anvil crawlers about half hour later, and that a huge gust of wind, which broke my back gate, and the thunder just didn't stop, just one constant roar for about to hours, that got slightly louder during close strikes.

Lol been watching french storm s all last summer, gonner miss that.

Day 2 Convective Outlook VALID 06:00 UTC Fri 20 Apr 2018 - 05:59 UTC Sat 21 Apr 2018 ISSUED 21:42 UTC Thu 19 Apr 2018 ISSUED BY: Dan Increased boundary layer moisture, with surface dewpoints of 14-16C likely, combined with breeze convergence / urban heat island may allow an isolated heavy shower or two to develop late Friday afternoon and into the evening - with particular focus on London, Essex and Kent. However, forecast profiles are very dry, and so any convection that attempts to develop will struggle to gain much height - hence a very low risk of lightning. On Friday night, the approaching subtle upper trough from Biscay will begin to destabilise a high ThetaW airmass advecting from France across the English Channel into S / SW England. There is some uncertainty at this range as to the degree of overlap between upper forcing and plume coming out of France, and this will affect how quickly elevated thunderstorms can develop. For now, have issued a SLGT for the Channel Islands and adjacent English Channel for early hours of Saturday given lightning will likely be fairly frequent with any thunderstorms that do develop, but this may need extending northwards into Devon east to the IoW, depending on how quickly destabilisation occurs in this forecast period (up to 06z Saturday). http://www.convectiveweather.co.uk/forecast.php?date=2018-04-20

Warmest day of the year so far here today as well, but a more modest maximum of 16.1C. Glorious evening sunshine as well. Flora and fauna all starting to spring into action. This doughty lass was on top of the hedge in the wee hoose's garden this evening. Cheeky...

Oooooo lovely more toasted baps time ... may throw a few snags on the bbq too

1 month ago: Today: Weird what a month can do!

I'm going to give my overview of the thunderstorm potential for the next few days up until Sunday. The main thing to note during this period is the dominance of high pressure which significantly reduces the risk of storms, along with lack of moisture and high CAPE values for majority of period. A few definitions for those who are learning I'll quickly go through them. CAPE: Convective Available Potential Energy - Measure of amount of energy for convection, therefore higher CAPE = quicker storm formation and more frequent lightning. DLS: Deep Layer Shear - A measure of wind shear between the mid levels of the atmosphere and surface. High DLS values means storms will become more organised and persistent bringing a greater chance of severe characteristics. SRH: Storm Relative Helicity - Measure of potential for cyclonic updraft rotation. Therefore higher SRH, greater potential of supercelluar characteristics. PW: Precipitable Water - Indicates the amount of moisture within the air. Higher PW greater chance of storm formation but too high and atmosphere becomes saturated. Tomorrow (Thursday): As you see from the graphs below, we are seeing SB CAPE values of 1000J/kg, this is as a result of strong diurnal heating. As a result we see a few storms form across CS England into East Midlands. The Netweather NMM model shows the formation of a convergence zone which set off these storms. It must be noted that whilst the NMM model produces storms, the lack of available moisture (precipitable water) and under the influence of high pressure, I cannot see much potential tomorrow. However if a storm does form, the low PW values along with 30-40knts of DLS, means that any storm may last a long time from its sustained updraft. Lighting amounts will be fairly infrequent. Friday: Friday warrants a similar risk to Thursday. CAPE values are fairly higher stretching towards 1500J/kg, but must be noted this isn't important if there isn't any available moisture. Again the NMM model are very generous with the breakout of storms, however precipitable water values are a little higher so I'd favour Friday over Tomorrow. We also see values of 30-40knts of DLS therefore any storm that does form will see more frequent lightning activity as the updraft will be long-lived. I must stress that even with these favourable parameters given high pressure is in control, we are more likely to see nothing rather than something. My best bet is just north of M4/Bristol Channel across SW Midlands. Saturday: A much greater risk lies on Saturday, at this point high pressure tends to move back away to the east. As you see CAPE values are even higher approaching 1800J/kg, showing the potential for some very frequent lightning. The reason there is a much greater risk of Saturday is because of the much higher precipitable water values, lower pressure (whilst still high) and a well-defined convergence zone. DLS amounts are rather slim for Saturday however, storm relative helicity values which represent the potential for cyclonic motion within an updraft, are pushing towards 150-200m^2s^-2. Therefore any storms on Saturday I expect to form along a line from North Wales towards East Anglia and the London Area, a few storms just North of M4, but lower risk. These storms will exhibit the potential for supercelluar characteristics but these will be relatively short given lack of DLS and may only occur within a tight time frame. All storms will have a relatively short duration but will result in some very frequent lightning. Sunday's potential remains to be seen as charts don't quite reach that time frame but interesting times nevertheless. I hope this have given you an insight on what we could expect this upcoming week. I'm still learning myself all the time so apologies for any errors.

No went to my south / east as per main thrust in the damn dover straits no doubt. Had a look at radar archive rings a bell initially it looked I was right in the pathway of fun time, sort of crumbled apart for me as it trundled north retained oomph to east, with you in Essex a recipient to a light show. Think I had some heavy rain a flash and a bang and that was about it. ? 2017 was woeful for storms here much better success to my southeast however. Saturday night looks interesting possibly elevated French imports? 0000-0215 (19/07/17)

Yep. Not too shabby for April, is it? I managed 26.7°C here, perfect set up for it too. That's the highest April temp I have recorded in 8 years worth of data.

Official high today is 29.1c as in met office stations the record is 29.4c No doubt some local stations will have touched 30c but they won't be protected from the sunshine so false data will display

London over time will break all heat records, the continuation of build build build , more concrete and tarmac , more traffic and pollution, a further reduction of green areas, will cause this. That's lovely for those that enjoy heat, humidity, and above all dangerously poisonous air quality. Or course those looking from Darlington or west Yorkshire will say how great it is ...... Is it all about 'likes' ? ............

1965 A month with some very interesting extremes. In contrast to the high maxima at the end of the month, a very low temperature of -21.7C was recorded in the same month at Corwen (Clwyd) on the 3rd, during a cold and snowy beginning to the month. This was the coldest day of the year - and an interestingly late date for this. We had to wait until 2001 for a lower temperature in March. The month began with cold NE winds, with some snow. It cleard on the night of the 2-3rd to give the low minima. There was then a notable blizzard in southern England on the 3-4th. It snowed for almost 24 hours at Heathrow, and there were over 20 cm of level snow on the Hampshire Downs and Salisbury Plain, and 35 cm in central Wales. There was deep snow and traffic disruption in north Wales and on Anglesey. There was even 10 cm on the Hampshire coast, although I don't remember this at all. There were 60 cm drifts in the centre of Birmingham. There was widespread traffic disruption. Then close to the equal highest maximum for a March day was set on the 29th: 25.0C at Wakefield and Whitby (although this record is more suspect than the 1968 one). At Whitby it was the hottest day of the whole year - this is the earliest date for the hottest day of the year at any location in the country. Wakefield is obviously the place to be in March. Strachan (Kincardinshire) saw the equal hottest March day (until 2012) of 22.2C. There were also some interesting extremes within 24 hours during this "heatwave": in East Anglia there was a range of 28C between frost at daybreak and the afternoon maximum. The possibility of such range in such a short time is one of the things that makes this time of year so interesting. The strength of the March sun played an important role in this heatwave, rather than the source of the air (hence the large diurnal variation.) The month had a sunny first half, but it was very dull from the 15th to the 21st, with only 2 hours of sunshine at Bracknell. It cleared on the 27th as pressure built, giving a sunny end to the month, with those very high maxima Not quite what you are looking for but this is a transcript from Britweather for March 1965

move over 2, 3 and 4 ... 26 max today and 10 min would be good for 18.0. Earliest on record. (18th provisionally 16.7 new 6th on above list. Note current 5th place 30-4-1827 hiding behind daily record 2nd place 30-4-1775.

The south-easterly sea breeze has kicked in now so it looks like 26.1C is our maximum for the day. It's smashed the April record by a whole 2.1C and is a mere 14.7C above the 1981-2010 average for the 19th April. For some idea of how warm that is for this location at this time of the year. In the last 38 years there have only been 9 days warmer than this before 15th June!

9.1 to the 18th 1.8 above the 61 to 90 average 1.3 above the 81 to 10 average ______________________________________ Current high this month 9.1 to the 18th

Lovely pleasant spring evening even at this time of night

As we embark along this impressive April warm spell, a couple of record may come under threat. 1: Most number of days with a CET of at least 15C - the previous record was 4 from 2011. The current forecast has us achieving a run of 5 consecutive days of at least 15C, starting today. Over the CET record, 15C+ days occur on average just once every 5 years. The longest stretch without was 24 years, from 1902 to 1925. 2: Most number of days with a CET of at least 16C - the previous record was 3 from 1795. The current forecast has us achieving 5 days of at least 16C. Over the CET record, 16C+ days occur on average just once every 18 years. The longest stretch without was 53 years, from 1950 to 2002. 3: Most number of days with a CET of at least 17C - the previous record was 2 from 1795. The current forecast has us achieving 3 days of at least 17C. Over the CET record, 17C+ days occur on average just once every 82 years. The longest stretch without was 169 years, from 1776 to 1944. 4: The warmest April week on record was the final 7 days of 1795, which averaged 15.1C. The current forecast has the week of the 16th to the 22nd average 15.6C I'll add some more as I find the time!

Disastrous outlook for Central Europe. Dry winter followed by dry spring. Daily averages already at summer levels on some days and dry as hell. Half the country heading to extreme drought and it's only April. Fun!