In Central England, the latest provisional figures for June show that 2017 is the joint third warmest start to a year (1st of January to the 22nd of June) since 1772. It’s very tight at the top but 2007 is still clear at the top, but that will gradually change because the second half of 2007 was much cooler than the first half of that year.
I’ve been watching 2017 climb slowly up the league table since March, but I think that this maybe as high as it gets, at least for a while, in light of the very much cooler conditions forecast for the coming week in the latest run of the GFS model (fig 3).
By this time next week this may current heat wave may be just a distant memory, that’s according to the latest GFS forecast, as the British summer monsoon gets into full gear.
A good degree of consistency between the UKMO and GFS models about how saturday will look at T+120 (figs 1 & 2). How accurate it will be is another thing entirely. Pressure is still forecast to be reasonably high across the south, 1000-500 hPa thicknesses are not far from 564 dm, but there is a fresh to strong westerly flow across the British Isles, with fronts driving in from the west, so things don’t look good for this current hot spell.
According to the latest GFS forecast, next Sunday might be a wet affair at Glastonbury (fig 1), as the current hot spell breaks down, and the weather turns wetter across the country, by next Sunday. Then again, all NWP models at this range are notoriously inconsistent, and with the Met Office never making public any of their NWP model data beyond T+120, it’s impossible to judge.
This really useful T+192 chart from the ECMWF (fig 2) for next Sunday is of little help. I really despair of the ECMWF, why are they so loathed to make public any of the NWP data that they supposedly generate for the people of the European countries that fund them? I ask you, of what value is a chart of MSLP overlaid with 850 hPa wind speeds to anyone? I thought my contouring had problems, have they never heard of smoothing, and please a summer chart with isobar spacing of 5 hPa is not that helpful. What about overlaying accumulated precipitation or precipitation rates, or even total cloud amount rather than 850 hPa wind speeds. Perhaps there is an option that I’ve missed on their website, but I don’t think so.
Figure2 – Courtesy of ECMWF
A little unfair of me perhaps, but this is a comparison of the last weeks sunshine from Kinloss on the Moray Firth in the north (fig 1), and Exeter in deepest darkest Devon in the south (fig 2). I’ll let the graphics do the talking. I’m sure that the balance will be redressed as the summer goes as they usually do. The GFS forecast still looks good, but thundery showers might be a problem for some areas next week.
The next eight days, particularly in the southwest of England look set fair, summer has finally arrived and with 1000-500 hPa thicknesses never falling below 564 dm temperatures will be in the very warm category if not hot. Of course you have to faith in the latest NWP guidance from the GFS model, but let’s throw caution to the wind and believe it will happen. It’s not all plain sailing, there will be some thundery showers scattered across some other parts of the country, and someone has forgotten to invite the north or west of Scotland to the party.
I may be chancing my arm here, but by this time next week (16th June), summer will have recommenced, well, at least across southern parts, that’s according to the latest NWP from the GFS model (fig 1). I should know better, and not be so naïve to trust models at this kind of range, but what the hell. I’m not promising it will last though (because it doesn’t), but high pressure is forecast to establish itself across the southern parts of the country, and maximum daytime temperatures will probably be well into the low eighties. As for the northwest of the country though, things still look windy and changeable, but at least the Atlantic low pressure systems seemed to have retreated to >60° north.
Here are the two solutions to what the analysis should look like at 00 UTC on Tuesday the 6th of June, made 48 hours before by the GFS and UKMO models. How did they compare with reality?
Figure 2 – Courtesy of the UKMO
For the purposes of this comparison I’ll use the Met Office midnight analysis to compare them against (fig 3).
Figure 3 – Courtesy of the UKMO
Positionally, the UKMO are very slightly closer to the centre of the low on the north coast of Wales, but both models are still a fair way SSE of the true centre. The Met Office intensity of 989 hPa is slightly higher than the 987 hPa it was at midnight, the GFS have it spot on. Shape wise, the Met Office edge it, having a slightly more elongated trough feature than the more rounded GFS solution. I adjudge this a draw, with both models providing good guidance at T+48 hours out. The only question that remains, is why, with a northwesterly gradient like that over the southwest, did they dither about with issuing a yellow warning for strong winds?
Quite a week of weather coming up for the British Isle in the next week, if these latest GFS forecast frames are anything to go by. Very mobile till the weekend, with a pulse of very warm air for Saturday and Sunday thrown in for good measure. The gradient over northeast Scotland looks very tight on Wednesday, and there’s plenty of more rain to come for western areas, both on Wednesday and Friday by the look of it.
I was just having a look at just how consistently the GFS handled Monday’s low by comparing the last three midnight model runs from the American (fig 1). And yes, it is quite consistent as regards intensity, but the latest track is now further south than it was in the T+96. Consistent of course doesn’t mean correct, so we’ll see what happens during Monday to see how correct.
What about the Met Office?
They have the low, in their latest T+48 forecast chart for midnight on Tuesday, over Worcester, with a minimum central pressure of 989 hPa (fig 2). The whole feature is much narrower trough like than the more rounded cyclonic GFS solution.
Figure 2 – Courtesy of the Met Office
As regards warnings the Met Office have kept it fairly simple, with no mention (so far) about any anticipated problems with strong winds or gale force gusts. I would have thought that with the tree’s now in full leaf, and especially in the strong west northwesterly behind the low, that this might have produced some impacts. In the yellow warning for rain that they have issued (fig 3), they’ve limited the area to Wales and the Northwest of England south of Ambleside, which is slightly odd, why not just map out the rest of the Lake District and be done with it. I never thought drawing blobs of yellow on a map was a very precise method of delineating an area on a map, and could never inspire much in the way of confidence in people who viewed the warning. Why not allow the forecaster to do it by region, or use forecast rainfall accumulations directly from the underlying NWP? At least the underlying map has been greatly improved.
Figure 3 – Courtesy of the Met Office