Model output discussion - hot spell beckons but then what?

[mushymanrob]

10 minutes ago, Mattwolves said:

Its foolish though to make predictions beyond a week in the uk regarding what the models currently show... You say every model shows unsettled!! The ensembles do not show any one weather pattern dominating. I mentioned the EC46 because it shows a month of 2 halves... Mixed at first, and improving mid month and beyond!! Especially away from the usual suspects. This may change tonight, on the other hand it may improve. Your entitled to your opinion, and I won't discredit you for it.. Let's just wait and see to how it pans out! 

indeed, it was just your suggestion that next week isnt nailed that i was questioning, because it does look unsettled with low pressure domination.  august might well be a month of 2 halves, but the first half doesnt look very inspiring IMHO, because the noaa charts , which are supposed to be the most accurate for their time period when consistent, retain pressure lower then average with a strong upper westerly flow.
we have had a run of below par/bad augusts since 2003 (although the southeast hasnt fared badly it must be noted) , every year the old mantra of 'there plenty of time left yet' has been touted on august 1st... ever since i joined in 2005.. but every year august has failed to deliver a proper summers spell.
im not writing august off... im just suggesting that given the current outlook and taking into account modern augusts, the future doesnt look too rosey, if its dry sunny warm/hot conditions youre after.

[mountain shadow]

12 minutes ago, Jon Snow said:

I'm bemused too, the models don't show autumnal or unsettled, they show changeable with alternating ridges and troughs, some warm weather, some cooler..normal summer weather!

You must be looking at different models to me then, as the output is most assuredly unsettled with an early Autumn feel for us in the North West. The latest 6z GFS has rain almost every day from Saturday through to the end of the run,

[mushymanrob]

12 minutes ago, Jon Snow said:

I'm bemused too, the models don't show autumnal or unsettled, they show changeable with alternating ridges and troughs, some warm weather, some cooler..normal summer weather!

bib... surely thats the very definition of unsettled!

[MATTWOLVES 3]

12 minutes ago, mountain shadow said:

You must be looking at different models to me then, as the output is most assuredly unsettled with an early Autumn feel for us in the North West. The latest 6z GFS has rain almost every day from Saturday through to the end of the run,

This is a common problem on this forum though. If it remains unsettled in the NW but much better in the South, we can't assume the conditions are bad countrywide! Karl is painting the picture has an whole, and he very often will reference the fact that conditions are most favourable in the SE, but not so good further NW. With low pressure to the W/NW yes, it's safe to say conditions won't be very good in your back yard, but further SE they should be quite a bit better. And let's not forget the skill factor of these models significantly drops after 5 days. 

[knocker]

1 hour ago, mushymanrob said:

well i do see the autumn comparisons. just look at these predicted charts and see where the air is sourced.... northern canada! so whilst it might not be 'autumnal' for a week or so, as the mean upper trough drifts eastward as expected on all models this next 7 days, it looks to me like theres a case to be made for it getting cooler and fresher... assuming these charts are accurate. (note - early signs of autumn, not full blown october like).

as for writing off the whole of august, mentioned above somewhere, again, these charts suggest the next two weeks will be unsettled with periods of wet weather with low pressure in charge. blocked patterns like this dont tend to disappear very quickly, so suggesting august will be a wet month (id liken it to august 2013 actually) is i suspect a fairly safe and reasonable thought.

You wont get any argument from this morning's EPS mean anomalies

[knocker]

Nice hres Modis

[danm]

1 hour ago, mushymanrob said:

well i do see the autumn comparisons. just look at these predicted charts and see where the air is sourced.... northern canada! so whilst it might not be 'autumnal' for a week or so, as the mean upper trough drifts eastward as expected on all models this next 7 days, it looks to me like theres a case to be made for it getting cooler and fresher... assuming these charts are accurate. (note - early signs of autumn, not full blown october like).

as for writing off the whole of august, mentioned above somewhere, again, these charts suggest the next two weeks will be unsettled with periods of wet weather with low pressure in charge. blocked patterns like this dont tend to disappear very quickly, so suggesting august will be a wet month (id liken it to august 2013 actually) is i suspect a fairly safe and reasonable thought.

Depends what you define as “autumnal” and which part of the UK you’re referring to. To me, autumnal usually means low after low barrelling into the UK, powered by a raging jet stream with heavy rain, strong winds and cool temperatures.

Yes, on the model output, next week looks increasingly unsettled, however the pattern is sluggish, blocked and we are already seeing a slow down of the progression of the low in the eastern Atlantic next week which leaves us with more of a NW/SE split - at least initially. In fact, it’s quite common in August for us to see low pressure anchored to the NW of the UK with the weather starting to go downhill across Scotland compared to the May-July period. 

It is also likely to be quite warm at times, particularly in the E/SE. Granted, it may feel autumnal at times further north, however what we are witnessing - whilst not glorious summer weather - is fairly common for late summer in the UK. Perhaps not the northern blocking, but the actual weather on the ground. 

Edited August 1, 2019 by danm

[Frosty.]

Looking at the GEFS 6z mean I can't see anything unseasonably cool / autumnal..indeed it looks warm and humid at times, especially further s / se... Deeper into low res theres the usual ebb and flow between the azores high / ridge and lower heights to the northwest which is preety normal, essentially a north / south / northwest / southeast split..unless I'm looking at a different model it's a predominantly changeable outlook with alternating troughs and ridges, the troughs affecting the northwest most of all where it would also be cooler at times and the ridges more effective for the s / se!!!!

Edited August 1, 2019 by Jon Snow

[mushymanrob]

re autumnal..... i was making reference to the anomaly charts for 6-14 days time, in which the air flow is expected to be sourced from canada. in a northwesterly behind any exiting low pressure system it will probably feel cool like early autumn. i did say "not full blown autumn like october" , just the first hints of things to come...and my reference to autumnal was in support of another member who had posted such.
this is not uncommon in august. and indeed it might not even happen, it is though reasonable to expect it with this synoptic pattern. yes, this is a cherry picked chart to prove a point, but its no worse then such cherry picked charts showing heat.

Edited August 1, 2019 by mushymanrob

[Scorcher]

16 minutes ago, mushymanrob said:

re autumnal..... i was making reference to the anomaly charts for 6-14 days time, in which the air flow is expected to be sourced from canada. in a northwesterly behind any exiting low pressure system it will probably feel cool like early autumn. i did say "not full blown autumn like october" , just the first hints of things to come...and my reference to autumnal was in support of another member who had posted such.
this is not uncommon in august. and indeed it might not even happen, it is though reasonable to expect it with this synoptic pattern. yes, this is a cherry picked chart to prove a point, but its no worse then such cherry picked charts showing heat.

I just think so much warm air has been stored up to our north that it's going to take quite a while for that cooler air to properly make inroads. This is demonstrated on the GFS 06Z for me- the cool air doesn't really make it properly to our shores before another low forms to our west and brings in more tropical air. Our supply of cool air has been cut off for some time now, which has sent it a long way north.

The August CET after the first 7 days isn't going to look autumnal that's for sure.

[Methuselah]

It's a worrying thought but, with a continuation of both warm SSTs and warm 850s looking likely, I can't really see much sign of any long-term respite from anomalous rainfall...At least, not until something changes. And changes drastically?

  

 

[mushymanrob]

20 minutes ago, Ed Stone said:

It's a worrying thought but, with a continuation of both warm SSTs and warm 850s looking likely, I can't really see much sign of any long-term respite from anomalous rainfall...At least, not until something changes. And changes drastically?

  

 

sadly i think you are right if the gfs predicted rainfall is... 3 pm tues-fri

[Frosty.]

The Gfs 12z operational shows plenty of warmth and sunshine between now and next midweek, at least across southern uk with temps into the low to mid 20's celsius daily despite often being at risk of heavy showers with thunder but the next few days look drier and sunnier thanks to a ridge so some welcome respite for the flooded areas!!..later next week further s / se stays on the warm side but it's cooler further n / nw.

[MATTWOLVES 3]

I'm not going to admit defeat here, but the 12z paints a poor picture out to mid month!! It's one of a few operationals painting the same picture..... Van goff it's not! Low pressure looks anchored over us, meaning unsettled at times with even some much cooler air being brought down from the North!! I've already stated a few times the month could be a tale of 2 halves.... Perhaps high pressure having more influence beyond mid month, especially towards the SW.. which would also coincide with exeters thoughts and the EC46 thoughts... Much water to flow under the bridge though just yet... A further plume can't be ruled out on the back of a dodgy 7-14 days anyway.. The first 2 plumes have already occurred at the end of both summer months so far.. Namely.. June and July.. So it has to be a possibility that a further warm  up would be possible later this month. I think in 2016 we received a hot spell in the final 3rd of August and again in the middle part of September... So i remain optimistic in that sense. But yes as it stands the outlook out to day 10 and a tad beyond does look very ropey!! But still plenty to play for just yet.... Like a September heatwave just in time for the kids to go back to school.... Now that would be typical... You kids get back to school while dad sips margaretas by the pool....

Edited August 1, 2019 by Mattwolves

[Frosty.]

Hey I found an autumnal chart..but it's after next week so plenty of time for that to improve!!!!!!!!!!!!!!!!!

[danm]

UKMO 12z pushes the low across us much more quickly than the 0z and earlier runs. 

[knocker]

Little change from the gfs in the 5-10 outlook this evening with the jet and trough corridor N. Canada > Atlantic > UK > European trough running south of the Greenland block, although the upper wind flow is so far south there is little eastward momentum across the UK. This portends changeable weather of sunshine and showers and the odd front traversing the country,  with temps around average

Spot charts

Edited August 1, 2019 by knocker

[Frosty.]

The Gem 12z becomes unsettled and cooler next week but then temperatures recover as the uppers (850's) warm up again as winds switch from the northeast back more towards southwesterly.

Edited August 1, 2019 by Jon Snow

[Methuselah]

For a while there, I was beginning to fear a Close Encounter of The Autumnal Kind...but, I am now pleased to see that, at the critical point, the GEFS 12Z Operational is in fact verging on being an outlier!

   

   

[Frosty.]

Hmmmmmmmmm this is a difficult choice but I think I prefer P7!!!!

 

[MATTWOLVES 3]

Ecm highlights... Low pressure looks to have the main influence next week with showers and rain at times, more especially to the W/NW.. Some signs of winds becoming more S/SWtly towards next weekend, this would bring much warmer perhaps humid conditions, and with low pressure close to the W/SW, thundery downpours couldn't be ruled out... Something for everyone, especially ducks....

[Singularity]

 

Somehow it's only ECM among operational models that really has a good go at keeping the trough west of the UK (after the earlier one's cleared off east).

This is the closest to the retrograded mean trough position, relative to what was common in July, that the El Nino standing wave coupled with seasonal wavelength adjustments and possibly a bit of help from the MJO (remains to be seen - much uncertainty thee) all suggest we could see manifest by mid-month.

At the moment, FV3 keeps on outputting runs that follow a whole different story; one fitting of a La Nina standing wave.

Possibly this has something to do with the model projecting a strange retrograde-amplification of tropical forcing across Indonesia (interference perhaps?). ECM/EPS shows no such inclination.

 

[knocker]

The general theme of this evening's EPS mean 5-10 pretty much as expected except perhaps the trough in the eastern Atlantic is a tad more defined. This has the effect of backing and weakening the upper flow which will probably result in less eastward momentum across the UK. Having said that it does not stop completely so we are looking at a changeable few days but rainfall could well be concentrated in western and northern regions

[damianslaw]

Not the best output today for high summer - slow moving trough feature, jetstream to our south, high pressure locked in hold to the NW - no sign of any sustained settled conditions for the foreseeable and temps apart from briefly in the SE around average, a bit below in the north next week. Not terrible, but has to be said not great for early august.

 

[summer blizzard]

GFS out towards day 10 is forecasting a strong trade surge near the dateline, that is likely a factor in its later outputs even if it usually applies the signal too quickly.