Model output discussion 14/04/18

[Mike Poole]

GEM demonstrates the expected evolution, I think, here's the 12z:

[ancientsolar]

16 minutes ago, SizzlingHeat said:

I think the 'red' colours are misleading you. The darker the red does not necessarily translate to hotter temperatures. You need to be looking at the 850s and thickness levels which represent the temperatures likely at ground level. The 850s on this run show widely 10-12c across the UK. With very dry ground and strong sun you would add approximately 16-18c on top of that temperature. Therefore 12 + 18 is going to provide 30c at surface level. 

The difference this week was the uppers were higher that next weekend. In fact, 13-16c widely across the UK last Wednesday and 13-15c across the west widely until Saturday which resulted in temps nudging the low thirties. 

The uppers today scraped 16c across the south resulting in a high of 32c.

Thanks, I am learning new things ~ Just checking those charts 850 charts
It looks like the upper winds have been favouring us resulting in the upper warmer air coming from Central Europe and also NW Europe. 
Seems like this switches to an ENE for next week(end) 
 

Edited July 1, 2018 by ancientsolar

[I remember Atlantic 252]

hopefully not true that GFS underdoes temps?

[Guest]

1 minute ago, I remember Atlantic 252 said:

hopefully not true that GFS underdoes temps?

Why, no warmer than today really even if you add 1-2C.

[Fourty Point Three Degrees]

GFS 12z is like one massive high pressure traffic jam spiralling right out into the Atlantic. Even by next weekend this spell will be 14 days old and theres still a monster sized ridge queuing up to get here. 

[summer blizzard]

47 minutes ago, ancientsolar said:

Thanks, I am learning new things ~ Just checking those charts 850 charts
It looks like the upper winds have been favouring us resulting in the upper warmer air coming from Central Europe and also NW Europe. 
Seems like this switches to an ENE for next week(end) 
 

Although uppers have been higher than average it's also notable that lapse rates at this time of year are about as high as they are going to get (~14C in June on average), this combined with high pressure pretty much over us is allowing a domestic warm pool to form as well (which is why in protracted spells you tend to find maxima edging up each day). Hence, that's how we are extracting the maximum from the current spell. 

17 minutes ago, I remember Atlantic 252 said:

don't mind it Chris, it's a very good summer, but being choosy I prefer days like mon to Sat just gone, 27 degrees ish with hardly any humidity, today way more humid with a SE breeze

Sunday-Tuesday felt quite humid here with Fr-Sat being by far the best. Wind is still gusty here but it feels warmer and more humid today. 

As feared, the Azores High rebuilding at the end of the week also looks to push up minima. 

..

With regards to the models and the second half of the month it's worth noting that for the first time in months (though it may change) trades are forecast to strengthen in the Pacific across the board. 

 

[Frosty.]

Looking at the GEFS 12z mean, although the week ahead looks largely fine, very warm / hot and sunny, bar a few isolated thunderstorms being sparked across parts of the s / sw, from the end of the week into week 2 becomes even hotter further south and we also have a large high building in to reinforce this gorgeous spell which is set to continue through to the middle of july (perhaps even longer) at least across southern uk..stunning summer this is fast becoming..a lot more to come too! 

Edited July 1, 2018 by Frosty.

[mb018538]

ECM looks great again. 

BBC long range forecast tonight showing 30c again in the E/SE next Sunday, so there’s not really any let up in the heat wave. Barely a drop of rain either. Some places are going to go from a 0mm bone dry June until at least the 10th July and possibly beyond now....which is slightly worrying!

[mb018538]

As others have already pointed out, due to high lapse rates/bone dry ground etc we aren’t needing huge uppers to pass 30c. They may only be around the 10-12c Mark next weekend, but it’ll be more than enough.

The state of the summer so far means that if we did get a proper full on southerly plume soon we could be looking at something very high indeed.

[Leo97t]

10 minutes ago, mb018538 said:

As others have already pointed out, due to high lapse rates/bone dry ground etc we aren’t needing huge uppers to pass 30c. They may only be around the 10-12c Mark next weekend, but it’ll be more than enough.

The state of the summer so far means that if we did get a proper full on southerly plume soon we could be looking at something very high indeed.

Suggestions of just that southerly plume suggested around the end of the ECM/GEM

[Frosty.]

Ecm 12z looks beautiful with a big anticyclone building in..staying very warm / hot.

 

 

 

Edited July 1, 2018 by Frosty.

[Nick L]

Folks, please keep general weather chat and posts about today's weather (including storm chances) in relevant threads.

[Man With Beard]

So tonight's ECM gives the likely maximum temps (if you assume its raw temps are 2C down as is usually the case) 

Tomorrow 30C

Tuesday 29C

Wednesday 29C

Thursday 31C

Friday 30C

Saturday 30C

Sunday 32C

Monday 31C

Tuesday 33C

If the 'cool-down' suggested for this week by some of the media is to be true, the ECM is going to be very wrong. 

Edited July 1, 2018 by Man With Beard

[Mike Poole]

ECM T240

Say no more!

[Frosty.]

Hot off the press, a very warm / hot and increasingly anticyclonic Ecm 12z ensemble mean..perfick

[Mike Poole]

ECM ensemble mean!  Last three frames:

Just awesome!  

[Singularity]

Just looking at the trade wind increase SB referred to earlier.

There are increases shown quite widely, but a notable interruption to that along the dateline which is of some note.

Also, I'm skeptical of the outlook from GEFS anyway, as it's predicting strange things for the MJO and Kelvin Wave combination at the moment. Some confusion, it would seem. Does anyone have a plot like the above but using EPS? I'm sure I've seen one out there somewhere but for some reason I don't have a link bookmarked. Thanks in advance.

 

Looking at the weekend into next week, you can really see how the high would retract to our west and stay there if it wasn't for the more Nino-like forcing coming together. Still some uncertainty over how fast it does so though, with GFS the slowest as usual. I think that slowness is behind the loss of strong ridging through the UK past day 10 on many recent runs. 

The N. Atlantic SST pattern will be playing its hand too of course. I have got the impression that the models don't resolve this very well beyond about 6 days range. So it may give us more leeway than usual for the 'poised' tropical situation at hand.

 

Now for what it's worth, here's a brief roundup of the ECM rainfall chances for the week ahead:

Monday - few light showers in SW, isolated ones eastern highlands of Scotland.

Tuesday - light showers move into much of the far south during the afternoon. I have seen other 12z model runs toying with this idea. Previously it just looked to be some high cloud.

Wednesday - scattered light showers across Cornwall, Devon, high ground in Wales, with isolated showers across Central & Southeast England. Few in NE Scotland, plenty in far-N. Scotland.

Thursday - widespread showers by the afternoon across E&W, a few on the heavy side. Some light rain or drizzle crossing much of Scotland before transitioning into heavy showers in the east.

Friday - still showers in E. Scotland, some heavy. Few elsewhere in that country. Some showers E&W but less than Thursday.

Saturday - well-scattered light showers for most. Some longer spells of light rain on high ground in the west - indicating a moisture-heavy tropical maritime airmass arriving.

Sunday-Tuesday - mostly dry apart from some persistent rain in W. Scotland on Monday.

 

So there is some scope for rainfall, but not much of it reaching usable levels. Best chance of that for E&W looks to be Thu-Fri thanks to a shallow low drifting across before being weakened to oblivion by the ridge from the Azores. Enough of a presence may remain to extend that potential through Saturday (as GFS 12z shows).

As far as temperatures go, well MWB has handily summed those up already . One extra detail - even with those showers on Tuesday, the far south still reaches the mid-20s. Also, I imagine the underestimation may be minimal during the more showery period, unless the available moisture and hence showers are being overdone, which is certainly possible given that only about 0.5% of the rain ECM had for me today has materialised (which is about 0.01% of what GFS had for me, ha!).

[damianslaw]

Many weather forecasters are having an easy time of it currently, with the consistent signal for dry warm and sunny weather - they certainly don't have there work cut out at present. It is also for anyone who likes to see variable interesting weather making for a very trying period for weather model enthusiasts in this regard.

I'm going take a week off from model watching - I do it from time to time when the weather is exceptionally benign and calm with little expected change for the foreseeable.

Perhaps as we head into the second week of July we may begin to see the atlantic exert a bit more influence, I can see subtle signal for lower heights to drop out of Greenland and put some forcing on the current high - just as occured in mid June.

[matty007]

1 hour ago, mb018538 said:

As others have already pointed out, due to high lapse rates/bone dry ground etc we aren’t needing huge uppers to pass 30c. They may only be around the 10-12c Mark next weekend, but it’ll be more than enough.

The state of the summer so far means that if we did get a proper full on southerly plume soon we could be looking at something very high indeed.

Very true. I honestly think you’d be pushing 40c with a strong plume. Maybe even surpassing it. The atmosphere and ground temps are so warm now. 

Not saying it will happen, but this summer is by far the best chance we have of achieving 40c if everything drops right. 

While the temps for some time now have been very consistent and very warm, we have yet to get anything truly hot. Think that will change before long 

[Captain Shortwave]

Looking at the end of the week, there probably will be a front sitting somewhere across the north of the UK as the boundary between the very warm air over the south and cooler polar maritme air which will be lurking as the next  ridge builds in from the Azores. This doesn't look like making it all the way south though and if anything by next weekend the front gets shunted away northwards again, but in particular the ECM does get this into northern (possibly central England).

Much cooler in the north for a time.

I only mention this as quite frankly this is likely to be pretty much the only weather feature that will affect the UK in the coming week with more cloud and maybe a few spots of rain. This could correct north or south on the coming suites but one to watch as getting north of that front would bring a brief respite from the warmth if you are that way inclined. There will be a few showers around as heights weaken a little bit but from next weekend it looks fine and settled increasingly warm again.

      

We are still not seeing a full displacement of the Azores high into Europe and as such the warm mostly comes from the tropical maritime air running in from the mid-Atlantic as opposed to the hot conditions over Morocco and Spain. The tropical maritime airmass isn't an issue given the strength of the ridge and solar input being close to its highest levels at the moment so cloud shou;d be too much of an issue.

Still temperatures will at the moment won't exceed the current level unless we get the high east of the UK with a deeper Atlantic trough to allow winds to veer southerly, even so 30C would certainly be possible under the above set up.

Edited July 1, 2018 by Captain Shortwave

[Frosty.]

The models look fantastic, generally very warm / hot and sunny with a small risk of further isolated storms across the south and perhaps a few showers for the far north at times, the outlook for the week ahead from darren bett is fantastic and then, unbelievably, it gets even more fantastic as a large high builds in and becomes centred over the uk..Fantastic!!

Edited July 1, 2018 by Frosty.

[Methuselah]

Aye CS, I noticed that on the Beeb's weekly forecast: a fresher feeling 30C, come next weekend!

[Leo97t]

If heights start to push east then the UK record is being smashed

[Mike Poole]

Couple of other models to look at GFS parallel and FIM9 at T240:

Any which way you look at it, the heat wave goes on, and on, and maybe on as well!  

[matty007]

Absolutely incredible longevity this weather. Was always my ambition to experience a 1976 like Summer. 

Must say it may come true this year. 

Edited July 1, 2018 by matty007