Thundery wintry showers

I admit that, for the first time since moving to Lincoln, I'm feeling a bit down about the weather outlook for the coming week. (For me, the dull wet May was redeemed to some extent by frequent convective activity, so I could at least focus on the positives). It looks cloudy with rain at times and the thunder potential has largely gone. My birthday (22nd) looks like being overcast, cool by day and drizzly, with north to north-easterly winds and fronts around a low pressure system out in the North Sea. Hoping for some kind of pattern change during the last third of June.

Watching out for my birthday (next Tuesday) now. I have to admit I'd quite fancy a slack showery cyclonic westerly as long as there aren't many fronts embedded in the flow - it would be a good setup for getting a thunderstorm or two on the big day here in Lincoln. (This is what is currently showing on the GFS + ECMWF operational runs). I didn't fancy the cool cloudy northerly type that had been showing a couple of days ago. Still a lot of uncertainty at this range of course. In the shorter term it looks like thunderstorm potential for Wednesday/Thursday has reduced with greater chance of the storms heading further east.

Lincoln has been near the boundary of the NW-SE divide over the last few days, it was very sunny on 12 June, but 10,11 and 13 June had a fair amount of cloud at times. The 10th was the cloudiest day, though the cloud did conveniently break up during the eclipse. Overall though sunshine amounts have felt quite decent, and it's certainly been warm.

Yes, the current model outputs remind me a bit of the setup of late July/early August 1994, though shifted a bit further east which could limit the overall amount of thundery activity, especially away from the SE. The GFS shows plenty of precipitation moving up off the continent but it's not clear if it will be primarily thundery in nature or more a case of "thundery rain" with frontal rain and maybe the odd rumble. July 1994 was certainly a thundery month at nearby RAF Waddington with thunder on 8 days. I recall reading that the south-west largely missed out, but the majority of central, northern and eastern England had somewhat more thunder than usual, a pattern which started around 24 June and persisted until 4 August. I also remember hail and thunder from showery north-westerlies on 3 and 8 June 1994, though this was more localised.

I got lucky in Lincoln today, it's been cloudy with just the odd brighter interval, but one of these brighter intervals coincided with the eclipse.

To me, the most amusing outcome would be if we get an official highest max for 13 June 2021 in the range of 29.7 to 29.9C, such that the quirky stat survives but only by the slenderest of margins. It's a possibility.

I might have been one of those who enjoyed the early part of that June 2019 spell due to location - I was in Exeter at the time and I remember getting a couple of rare thunder-days out of it, including quite a potent thunderstorm on 10 June, just to the west of the main rain area, with some fork lightning to the west. (I didn't get many notable thunderstorms while I was in Exeter - occasionally I got big ones coming in off continental Europe if the surface winds were easterly and the upper winds southerly, but mostly it was just one or two rumbles). If I remember rightly it turned generally dull and wet in Exeter for a while from the 11th though. In my current area of the UK (Lincoln) it was a rather different story, exceptionally wet with flooding on the 10th-12th, caused by frontal rain.

It's looking "touch and go" as to whether it survives this year. The last few ECMWF operational runs have been building a pool of hot air over south-eastern Britain, which is evident at the 500hPa level as well as 850hPa: 850hPa temperatures are forecast to be 13-14C over the south on 13 June, so we could sneak a 30 or 31C out of that I reckon. This is also supported by the latest GFS run which has 850hPa temps rather less high (11-12C) and predicts max 2m temps of 28C in the south-east.

Yes, I've been noticing a lot of conflicting posts regarding sunshine, but I think a lot of it is down to location. On average the south coast of England is the sunniest part of the UK, but during this June so far many parts of central and northern England have had more sunshine than the south coast - hence sunshine being a little below normal in some southern coastal areas, but well above in many central and northern areas. (I'm not so sure about Wales or Scotland sunshine wise). I agree that it looks like flipping around as we move into an anticyclonic/south-westerly type. I look set to be just on the right side of the NW-SE divide over the coming week, but it could be a frustrating spell of weather for many of those over much of Scotland, Wales and the north and west of England.

The University of Lincoln's weather station is giving 24C with 65% humidity. A couple of thunderstorms have passed nearby, one to the west which gave a few distant rumbles, and one just to the east which gave some quite loud thunder and I saw one flash of cloud-to-cloud lightning. It was mostly dull here yesterday apart from a couple of sunny intervals mixed with showers in the evening, but today has been mainly sunny so far.

Thunder over Lincoln, I heard a couple of distant rumbles from a cell to the west at around 12:30, and another cell has come much closer in the past 15 minutes giving some quite loud rumbles. I haven't seen any lightning yet, though, it must be mainly cloud to cloud lightning.

Showers developed over Lincoln yesterday, a couple of which were heavy, but I didn't hear any thunder. There were some more showers around 7am, when I woke up with intense cramp in my right calf. It's been sunny since 9am but there's more convection going up now, so I'll be keeping an ear out for thunder this afternoon.

I note that the longer-term outlook from the models has the Atlantic trough weakening, resulting in more of an Azores High ridging pattern rather than the Euro high/Atlantic trough scenario. This would be consistent with the high pressure eventually retreating to the west and/or south, but probably not until around midmonth.

The ECMWF ensemble mean at T+240 has a 1025mb high over much of the UK, which agrees strongly with NOAA's 8-14 day anomaly charts and shows a remarkably high amount of agreement at that range. The GFS 06Z is an outlier regarding sea level pressure, though as Singularity mentioned, not entirely without support. The GFS ensemble mean, though less strong than the ECMWF ensemble mean, also has high pressure persisting out to T+240: Thus a continuation of the anticyclonic theme looks probable out to 12 June at least. There are hints of the high drifting westwards but it's worth noting that many model runs had eastern Britain under northerlies into early June about a week ago, and it didn't happen.

I don't have any objections to the outdoor weather which is just moderately warm, I can see why some would struggle indoors with lack of air conditioning and the house becoming a heat trap though. I remember a few days last summer when it got too hot indoors for me. Today it's 25.6C in my living room, which is acceptable, but I tend to struggle to work productively in it if it approaches 30C. The bottom line though is that you can never please everybody! That said, I imagine that the current weather is pleasing a pretty high percentage of the population.

I would like to mention that April wasn't generally cloudy or drizzly though, averaged nationally it was about as sunny as last year's April and it was also very dry. There is a tendency to refer to all cold weather after an arbitrary date in March as grey and damp, probably because it isn't wanted. I can't deny that May was a dull wet month for most though, with a few autumnal depressions thrown in, notably on the first Bank Holiday Monday. It does feel as if the weather has flicked a switch into summer following nothing summer-like after the brief warm spell at the end of March (April was sunny and dry as noted earlier, but for the most part too chilly to resemble summer). It's happened before - early June 1975's switch-around following a very cold spring was a particularly famous example.

Yes, there's evidence that our hot weather sources, particularly in north Africa, have warmed faster than the global average in the summer months (by 2 to 3C since the 1961-1990 period). If I was still living in Exeter I'd agree with that, but here in Lincolnshire those setups have a habit of bringing low cloud a fair way inland off the North Sea (early June 2013 was a good example).

I guess that one issue with the warming climate is that it is set to become increasingly difficult to get a dry sunny summer without prolonged heat that is uncomfortable for many, particularly in the SE. Since the 1990s, my "ideal" summer has had a frequent Atlantic trough/Euro high type setup with sunshine and low-mid 20s when the high is over the UK, some hot thundery outbreaks (typically mid-high 20s, occasionally low 30s) when the trough comes closer to the west giving southerlies, and some cooler (high teens/low 20s) interludes when breakaway lows move from west to east bringing sunshine and showers with thunder. However, it's become increasingly apparent to me in recent years that it's getting harder to have a summer like that without getting excessive sustained heat, or brief spells of record breaking heat. It didn't seem to take much to generate the record-breaking heat of 1 July 2015 or 23 July 2019 for example. Earlier heatwaves like those in the summers of 1975, 1976, 1990 and 1995 tended to require several days of high pressure and/or hot air coming up from the south to generate the heat, while 1989 was a good example of a dry sunny summer that rarely got particularly hot. However, the first half of June 2021 could well manage it because we do have this Euro high/Atlantic trough setup and we've just come out of an unusually cool spring for recent years, meaning that SSTs are relatively low, and also the first half of June is usually cooler on average than the rest of the summer. I do feel for those on the east coast who are feeling the wrath of those low SSTs though. I used to live in South Shields and they're currently struggling to exceed 13C, even when it's sunny.

June 2017 was an odd month, very warm but also dull and wet, apart from the SE which had near or slightly above average sunshine. The warmth came mainly from a very hot and sunny spell in the third week, which at the time was the hottest June spell since 1976, though roughly equalled in late June 2018. I remember my birthday (22nd) being depressingly overcast in Exeter following a week of sunshine and temperatures of 25-30C. It wasn't just global warming either - had the same synoptics been repeated 50 years earlier it would still have been on the warm side. There was a historical parallel in June 1966, which was statistically similar (warm but generally very wet, fairly sunny in parts of eastern England but exceptionally dull in Scotland and Northern Ireland). But even there, the specifics of the month were rather different - June 1966 had an unusually high frequency of thunderstorms in most parts of the UK, as far north as the Scottish Lowlands, whereas June 2017's rain was mainly frontal, via strong Atlantic lows in the first and last weeks. June 1982 was another warm but dull and wet June, but again, over England and Wales much of the rain was associated with thunderstorms. Yes June 2010 was dry and sunny. In Norwich I remember a dry sunny first week, then a couple of thunderstorms, then a fair amount of cool cloudy weather around midmonth, but plenty of warm sunshine from the 22nd onwards. In East Anglia and the SE this warm/hot dry sunny weather also continued for a large part of July 2010 with temperatures regularly in the mid to high 20s Celsius and occasionally into the low 30s, but it turned dull and wet in the north and west from early July.

We seem to have drifted into the Euro High/Atlantic trough pattern for early June. The Azores High is often cited as the main thing to watch, but in the setup that's currently forecast, rather than having a stronger than average Azores High ridging up to the UK, we have a flattened Azores High and low pressure out in the Atlantic, but the jet stream is being deflected northwards as it approaches the British Isles, with a dominant anticyclone over north-western Europe. This pattern was a recurring feature of June/July 1976, July/August 1995, summer 2003, and in the Julys of 2006 and 2018. The UKMO shows the Atlantic breaking through at T+144 but I expect that if there was a T+168 it would show a reload of the current pattern with another ridge of high pressure heading up from the south-west. The ECMWF ensemble mean also has this NW Euro high/Atlantic trough pattern going out to T+240, with a >1020mb high centred over the British Isles. That's pretty significant, as I've noticed a tendency for the ECMWF ensemble mean at days 8-10 to be overly hasty in bringing the Atlantic in. A potential "fly in the ointment" (as the saying goes) with this pattern at this time of year is that at some point during June we often get the "Return of the Westerlies", with the Azores High strengthening and the jet stream powering up to the north of the high. This could result in the Atlantic trough heading east towards Britain later in the month, and my feeling is that this is most likely around 15-20 June. However, that's a long way off, and there's no guarantee that any such breakdown to westerly-dominated weather would last particularly long. At one end of the spectrum you have the likes of 1992 and 1993, where westerlies set in during late June or early July and then persisted for much of the rest of the summer, but at the other, you have the Junes of 1976, 1995 and 2018, when the westerlies arrived around 15 June, but proved to be very short-lived, and high pressure built over the UK starting around 21 June.

A warm first half of June, cooler in the second half but not enough to offset the warm first half. 15.4C and 46.3mm please.

I was up in the Vale of York that summer, June was warm and quite dry but rather cloudy, I remember getting a couple of thunderstorms when I had a trip to Norwich around 8-10 June. July 2014 was pretty similar to July 2013 in that area of the country with spells of warm/hot dry sunny weather and some thunderstorms late on in the month. I also remember some quite big ones coming up from the south late on 19 July. August 2014 was cool and wet as others mentioned, but I wouldn't put it in the same class as the likes of August 2008, as sunshine amounts were well up to the average. I remember a thundery washout on the 8th and an autumnal depression on the 10th sandwiching a sunny day on the 9th. September 2014 was warm and dry but, like June, surprisingly cloudy. Thus, personally I tend to remember the summer half-year of 2014 as having a particularly good July, ratherthan summer.

Recent years saw an early melt-out over the Eurasian side of the Arctic - I remember that last year saw record breaking warmth over that side. Following a relatively cold winter and spring the ice north of Eurasia has been holding up somewhat more so far this season, but I can see the coming week reducing the chances of this situation persisting later in the season, with large temperature anomalies and southerlies pushing the ice towards the pole. I'm not actually expecting too much obvious damage in the next week or so but I expect that this week will make the ice more prone to melting out when we get warmer southerlies from Eurasia later in the melt season.

Yes I was thinking that, the University of Lincoln weather station had it at 12C min last night and 21C so far today, which suggests an outcome of around 17C (and Lincoln tends to be quite similar to the CET zone in the summer half-year). The GFS in particular often underestimates the temperatures. I wouldn't be surprised to see a final provisional result of 10.3-10.4C, falling to 10.1-10.2C after corrections.

I spent summer 2003 in Tyneside and remember June 2003 being quite unusual in that it was changeable but very warm and sunshine was generally above average except in western Scotland. It particularly stood out warmth and sunshine wise after a run of rather cool cloudy Junes. I remember it not feeling like a particularly wet month either because although rainfall was above normal, a lot of it fell in a few thundery downpours (8th, 17th and 22nd - 2003 was the one year when I had thunderstorms on my birthday on 22 June). In contrast to the warmth of August 2003, the warmth of June 2003 was consistent rather than outstanding. July 2003 had rather less sunshine, near to slightly above average in the east and below in the west. After the heatwave early in the month, August 2003 had a SW-NE split with the NE continuing sunny and dry, but cloudier towards the SW, I recall Shropshire in particular being relatively cloudy. It didn't compare to the Augusts of 1947, 1976 and 1995 sunshine wise, but due to the lack of other outstandingly sunny Augusts, it just beat 1975, 1933, 1989 and 1983 as the 4th sunniest August on record for the UK as a whole. There was considerable regional variation here, but in Tyneside the summer also sticks out for some spectacular thunderstorms, particularly on 17 and 22 June and on 10 August (the day that the SE had record breaking temperatures).