Model Output Discussions 12z 01/06/2017

[Frosty.]

I would bank the Gfs 00z operational run, it's showing a return of summery weather later this week as the azores ridge builds in across the south..The north has to wait a little longer but it's worth it as  a new anticyclone builds in from the west next week. At last the north of britain would  have something to smile about with warm anticyclonic conditions nationwide..prolonged fine spell but with a risk of thundery showers developing in the south for a time next week but overall very summery !  

Edited July 11, 2017 by Frosty.

[Yarmy]

On 7/10/2017 at 08:35, mushymanrob said:

interesting developments on the noaa's overnight, suggesting a pressure rise across the uk and possibly suggesting the beginings of the expected long hot settled spell?.. of course more runs are needed but theres room for optimism if you want hot weather.... theres at least a lot of mainly dry, sunny, warm weather on offer with the possibility of some real heat too. potentially great charts IF they firm up with subsequent runs.

 

I'm slightly wary of the anomaly charts produced over the weekend as they are generated automatically without further tweaking from the pros. Yesterday's update was less bullish, but despite that a comparison of the 6-10 with the 8-14 shows an improving picture.

 

[Man With Beard]

GEFS this morning quite an upgrade for settled weather in the D8-D15 period: 

the mean being fairly representative, with just 3 out of 22 runs keeping the Atlantic trough as a major influence over northern parts.

ECM mean is not as impressive, though, keeping Atlantic activity close to northern areas. However, this picture would still be a big improvement on the current situation. I would still expect the trough to lift out further in the days that follow.

The GEM op, GFS op and GFS control at D10 reflect realistic possibilities within the ensemble sets. The control run (middle) has the Scandi heights lift that some of us have been looking for, and presents the possibility of a rather extended period of dry, settled, and potentially hot weather. The ECM op is the most pessimistic run, but even this shows a very lonely trough, likely to lift out soon after. 

      

The GEFS ensemble set for Glasgow is very good for that location, and shows the potential for a mid-term warm-up well. From D10 and D16, the main cluster is between 8C and 11C at 850Hpa, which would represent the low to mid twenties *in good weather!

 

 

Edited July 11, 2017 by Man With Beard

[Frosty.]

Wow an impressive upgrade from the Gefs 00z mean with heights extending from the azores to scandinavia after this short cooler / changeable blip..looking good for a return of summer and an arrival of summer across northern uk!

Edited July 11, 2017 by Frosty.

[knocker]

The EPS not fully into boost the Azores mode but quietly revving at the moment. Note that the influence on the upper flow is not height rises over Scandinavia per se but the influence of the orientation of the trough and the extended ridging in eastern Europe. But the EC46 is very positive this morning not that that will be of interest as it's considered by most to be a load of tosh.

 

 

Edited July 11, 2017 by knocker

[Man With Beard]

5 minutes ago, knocker said:

But the EC46 is very positive this morning not that that will be of interest as it's considered by most to be a load of tosh.

I did notice that - personally I find its reliability quite good for week 2, mixed for week 3 and not too useful after that. Week 2 and Week 3 below:

  

[mushymanrob]

2 hours ago, Yarmy said:

I'm slightly wary of the anomaly charts produced over the weekend as they are generated automatically without further tweaking from the pros. Yesterday's update was less bullish, but despite that a comparison of the 6-10 with the 8-14 shows an improving picture.

 

fair comment, but im still encouraged by these current charts , and the ops are heading that way too . ok, things arent black and white and height pressure domination (we look like being stuck between the azh and euro h) doesnt automatically equate to heatwave. we could end up dry but overcast, most of august 79, 91, and 94 was like that here - even in 76 we had overcast but dry days. as i see it, we are heading for at least average but likely above average and the dry theme continues - for england and wales at least. and theres always a chance of some hotter spells - id be extremely surprised if we didnt get any, especially with the way the charts are going.

[Glacier Point]

Indeed Rob.

With the broadscale drivers all well set, next week's little low cutting SE will be all important in determining how much heat gets into Europe (after all, this isn't without precedent having occurred twice already this season). This will become increasingly difficult to shift over the next 6 to 8 weeks (note how 06z GFS retains heat over a large swath of Continental Europe). The tantalising prospect of low heights over Greenland engaging with Atlantic troughs to sweep up wave after wave of warm air across Europe. A hybrid 1995/2003 pattern ?

[knocker]

Apropos nothing at all really but a good example of a frontal inversion on Cambprne's 00z ascent and two airmasses. And the rain duly arrived around 0900.

 

[Man With Beard]

Latest GFS is the most bullish to date on a general height rise just after mid-month. Continues warm and sunny to the end, apart from a one day blip for the north in the middle

Latest GEFS coming out is 90% an board from D8 onwards, with a few proper heatwaves options thrown in.

Getting closer.

[Singularity]

Quite a range of scenarios with respect to that low passing S of Greenland early next week:

A) The very progressive 00z ECM which moves it quickly NE and intensifies it into a fairly deep system which is able to push close enough to the NW to provide a quick exit route for a shallow low that forms on the periphery of the heat plume.

B) The less progressive 00z GFS and (given similarities at +144) UKMO runs which still take the low NE but as a weaker and slower feature, allowing more of a ridge to build across the UK with the low on the plume periphery unable to find an exit route (despite a couple of days of trying in the case of the 00z GFS).

C) The 00z GEM and 06z GFS which take the low E then SE, dropping it down well-west of the UK on Wednesday. At this point GEM displayed it's usual strong enthusiasm for advecting the plume and associated peripheral low northward, leaving us waiting for a reload of high pressure from the SW on Friday following a warm (very warm in south) but thundery Wed-Thu. GFS is a different story, with little in the way of northward plume and low movement. This is due to a much stronger ridge of high pressure through the UK which is in place thanks to the Atlantic jet stream being orientated more SW-NE than W-E. 

 

Personally I feel the balance of probability is toward heights more high than low just NE of the UK so a more SW-NE jet orientation, but if that low heads NE instead of SE then there will be enough of a kink in that jet toward the UK to cause some trouble (opening the door at least briefly for lows drifting N/NE from Europe) anyway.

So there's a lot that has to go right to get a lengthy fine spell out of this. It just so happens the background signals favour just that, but as usual this cannot rule out the smaller-scale details that can interrupt the adjustment of the pattern toward what the signals are encouraging so we do need the usual dose of luck if we are to experience a nice smooth ride .

[Frosty.]

I know we keep talking about this being a cooler changeable week and today there is a lot of rain spreading from west to east across England and Wales but actually the coming few days indicate plenty of sunshine and pleasantly warm temperatures...and that's even before the azores high ridges in across the south in time for the weekend and the potentially increasingly anticyclonic and warm spell next week..it's not looking bad 

[Summerstorm]

Pretty good video here talking about the general pattern contrasts between the ECM and GFS but with the emphasis on some WAA next week  

 

[Fourty Point Three Degrees]

9 minutes ago, Summerstorm said:

Pretty good video here talking about the general pattern contrasts between the ECM and GFS but with the emphasis on some WAA next week  

 

Is that person a member on here?  

[Summerstorm]

Not sure to be honest @40*C but he has a youtube channel here though - https://www.youtube.com/user/GavsWeatherVids

Edited July 11, 2017 by Summerstorm

[northwestsnow]

Well nothing has happened yet but wow , GFS 12z is nothing short of spectacular as we move through the next week as the azores/ euro high dispatches the jet north and sets up the UK for a warm settled spell of weather.

You really got to take your hat off to Exeter they have been gunning for this for quite a while and it *looks* like they might well have been onto something! Kudos to Tamara GP and others who have also been suggesting improvements are on the horizon..

Oh me of little faith!!

Edited July 11, 2017 by northwestsnow

[Frosty.]

Watching the Gfs 12z blossoming into a beautiful run as high pressure takes over, next week looks very nice nationwide with the north warming up too..could this be the first nationwide summery spell?..it's looking like it!

Edited July 11, 2017 by Frosty.

[TJS1998Tom]

WOW! The 12z today though looks incredible, this is looking very good for the final week of July. Hinting temperatures in the high 20s from 26 - 29 degrees lasting up to 7 days over most of the country with hints of a thundery breakdown in the West (even though its still far away) but does look promising, and if you add two or three degrees on top it wouldnt surprise me if a lot of us saw 35 degrees at one point

Edited July 11, 2017 by TJS1998Tom

[Fourty Point Three Degrees]

Hmmmm GFS 12z says a repeat of July 2013 all over again.....

[Frosty.]

And it goes on..and on..and on, another great spell for southern uk and signs of a reboot from the azores at the end. 

[knocker]

Quite an interesting gfs

It develops a little breakaway upper trough post the weekend which develops into this during the week

Thus a very slack pressure area develops on the surface with a light southerly drift and some warm temperatures at the end of the week. It will be no surprise if the ecm does not go along with this

Edited July 11, 2017 by knocker

[mushymanrob]

1 hour ago, 40*C said:

Is that person a member on here?  

i believe so, but its not up to me to say (and i might be wrong).

[mushymanrob]

stunning gfs 12z.... absolutely stunning, and its not totally impossible either , ok its probably over estimating but its consistency is there, all we need now is a slight shift in the anomaly charts to support this and itll be game on!
 

[Singularity]

The major models so far this evening, from least to most desirable (if you like very fine summer weather):

  

It's curious that GFS keeps on making a lot more of the second push of high pressure from the southwest Sun-Mon, and GEM a lot less, while UKMO is happy to sit in the middle ground.

When it comes to the behaviour of that low S of Greenland, it's not clear whether UKMO would take it NE to pass by the UK with little direct impact such as GFS goes with this evening. It does seem though that the idea of it cutting S/SE has lost favour with the det. runs. GEM is now almost as aggressive as the ECM 00z was with the feature so that makes one wonder. 

If we do take the halfway house that is UKMO then prospects look reasonable enough in the south and then - at last - in the north by around Tuesday evening (though this second part is another case of extrapolation!).

 

GFS remains the best fit for the background signals but there is a risk that it's being too clean/simplistic with the Azores-Scandinavia ridge setup - this relating to the usual overly smooth jet bias (not enough kinks). Something to bear in mind, although it doesn't explain the enthusiasm for the ridge being so strong to start with; this comes from the Azores High itself simply being 3-4 mb stronger (but why is that, I wonder? Different handling of tropical forcing on the Hadley cell?).

[Mark wheeler]

Ecm doesn't look to shabby to me .