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Model Output Discussions 12z 08/03/17


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All thoughts on the weekend - indeed a bank holiday one, and the best of the bunch in my book. Last year we managed a wonderful May bank holiday weekend- whit, very warm on the Sunday here, one of the warmest days of last summer. I suspect if you look back at weather records, whit may bank holiday on average far more often settled and pleasant than the late August one..

There are lots of uncertainties what may happen over the weekend, where will the shallow low pressure forecast to move up from Iberia decide to position itself. How warm will it become? Speaking of temps, remember a maximum temp is a max, might only hit the figure for a few minutes, whilst significant part of the day is 2-4 degrees lower. Max of 30 degrees shown by BBC in a favoured localised spot only as well. 

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Much as previously intimated, I'm no longer inclined to posting much at all on these threads, winter or summer, but admittedly the perspectives offered sometimes prove too much to resist responding to

Do they?  Oh ok, right you are then. You could of course have quoted said "way of the pear" musings by way of illustration - but I accept that would conflict with the real purpose of the post and

So, the steadily improving picture emerges, from a sea of apparent doubt, and as suggested is timed quite nicely for the approach of summer That background ENSO neutral > weak Nino signal impr

Posted Images

4 minutes ago, Man With Beard said:

The ECM run has got me thinking about the all-time record of 32.8C. A 20% chance of going on Sunday or Monday if the ECM scenario sticks, imo.

Doubt if 30 will be breached if I'm honest. 

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1 hour ago, Ross Andrew Hemphill said:

What is this caveat you speak of? :cc_confused: And if those charts came off, it wouldn't only be this forum in meltdown! Lots of positive signs for really great weather in the next few weeks, everything just has to fall into place for us for once. :D

Standard for long range models e.g. still an experimental science, sometimes well wide of the mark, not to be taken too seriously therefore.

CFSv2 has historically been particularly unreliable, but it seems to have improved since the turn of the year.

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1 hour ago, SizzlingHeat said:

Doubt if 30 will be breached if I'm honest. 

Any evidence or just a hunch? Even the BBC and Met Office forecasters are predicting the strong possibility of 30C anytime between Thurs and Sat.

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1 hour ago, SizzlingHeat said:

Doubt if 30 will be breached if I'm honest. 

1 hour ago, SizzlingHeat said:

Doubt if 30 will be breached if I'm honest. 

Maybe not on a Dorset beach but my.location most probably will! Or Heathrow if SE flow

 

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30C looks doubtful to me, very doubtful but if it's going to be achieved it'll be Thursday- why?- because Thursday sees the UK under the influence of HP with little wind to speak of

h500slp.png

Just a light breeze for most- so with still air and strong insolation (and warm uppers) a hot day in built up areas especially.

Fast forward a day or two and the winds freshen from the SE

h500slp.png

Still warm but gusty

ukgust.png

Even more so on Saturday

ukgust.png

Hence GFS has temperatures nowhere near 30C

ukmaxtemp.png

Not even N France is shown to breach 30C. People can say the GFS undercooks temperatures but I doubt it's undercooking widely by 5-6C

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5 minutes ago, CreweCold said:

30C looks doubtful to me, very doubtful but if it's going to be achieved it'll be Thursday- why?- because Thursday sees the UK under the influence of HP with little wind to speak of

 

ukmaxtemp.png

Not even N France is shown to breach 30C. People can say the GFS undercooks temperatures but I doubt it's undercooking widely by 5-6C

Is that a 28ºc just East of Loch Eriboll on the North Coast? Fohn effect of the SE wind in the NW Highlands could certainly help inflate the temperature there.

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4 minutes ago, skifreak said:

Is that a 28ºc just East of Loch Eriboll on the North Coast? Fohn effect of the SE wind in the NW Highlands could certainly help inflate the temperature there.

Checking the hi-res it's a 23C. 

114-778UK.GIF?23-18

Obviously the ECM would be different but its evolution around the weekend looks iffy to me- nothing scientific but all looks too slack for Saturday. I would imagine its 0z run will look different.

Edited by CreweCold
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5 hours ago, CreweCold said:

30C looks doubtful to me, very doubtful but if it's going to be achieved it'll be Thursday- why?- because Thursday sees the UK under the influence of HP with little wind to speak of

h500slp.png

Just a light breeze for most- so with still air and strong insolation (and warm uppers) a hot day in built up areas especially.

Fast forward a day or two and the winds freshen from the SE

h500slp.png

Still warm but gusty

ukgust.png

Even more so on Saturday

ukgust.png

Hence GFS has temperatures nowhere near 30C

ukmaxtemp.png

Not even N France is shown to breach 30C. People can say the GFS undercooks temperatures but I doubt it's undercooking widely by 5-6C

The GFS actually doesn't show a single day where we get into the mid-twenties, let alone closing in on the 30C, for example Thursday

   84-778UK.GIF?23-0   arpegeuk-41-62-0.png?23-06

GFS just 21-23C with just NW Wales getting to 25C. Arpege calling for 25-27C widely 

Friday similar

108-778UK.GIF?23-0   arpegeuk-41-86-0.png?23-06

To me the GFS does look to be undercooking the temperatures by a good few degrees, add to that it is really washing out the warmer 850s which may or may not be correct, arpege last summer was a lot closer to the general temperature range.

Still no real agreement on the evolution over the weekend, complicated by an area of low pressure running along the jetstream towards Iberia and how this interacts with the ridge over Europe. As such no agreement on timing of any breakdown and hence when cooler air from the west makes it across the whole of the UK.

 

Just as an aside, can we try to keep things on topic in here, I know that might be difficult due to the horrific events of last night, but there is a thread open to collect our thoughts and emotions on the event. Thank you.

 

Edited by Captain Shortwave
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Latest runs water down the weekends warmth yet again. Saturday showing maxes of between 23-25c with increasing cloud, a freshening breeze and a chance of some showers. Sunday shows the majority of the plume has been pushed east of the UK, leaving a legacy of high cloud and temps between 21-23c whilst Monday between 19-21c with sun and clouds. 

 

It is such a shame but the ukmo is showing similar and ecm really on its own for prolonging or intensifying the warmth. BBC certainly going to re think the 30c for Saturday because they are going to be significantly off the mark imo.

 

Still.... Time for changes being 3 days away but the general evolution is there now. Still warm overall but the phrase 'hot' will be used less frequently by meto by end of today.

 

The weekend looks to be warm/very warm to begin with and becoming increasingly unsettled with showers, but some sun will remain, especially in the south East.

 

Regards

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The Ecm 00z is fantastic if you love heat..no downgrade..it shows a very summery spell which continues well into next week.:)

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Edited by Knockers
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The ECM continues to model the weekend differently with it again rebuilding the Euro ridge with very warm to hot conditions persisting until the middle of next week when we finally see fresher conditions push east. 

ECM1-96.GIF?23-12  ECM1-120.GIF?23-12   ECM1-144.GIF?23-12

An increasing risk of thunderstorms breaking out and heights lower but again temperatures close to 30C again.

It will be interesting to see whether the ECM has got the handle of that southerly tracking low correct and hence is right about extending the warmth through into the following week.

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I think we are still on for 30-32c during the weekend as our high drifts east into the north sea and we import increasingly hot and humid continental air up and across the uk with scorching sunshine and a growing risk of T-Storms breaking out..and it's not even summer yet!:D

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27 minutes ago, Knockers said:

I think we are still on for 30-32c during the weekend as our high drifts east into the north sea and we import increasingly hot and humid continental air up and across the uk with scorching sunshine and a growing risk of T-Storms breaking out..and it's not even summer yet!:D

I think you will find it's unlikely the temps will get much past 27 perhaps 28c. Likely for Saturday only as growing agreement for Sunday to be cooler and cloudier. It's nice to try and hold out hope from the ecm but even if the uppers are correct, I feel too much cloud with scattered showers will reduce the chance of 30 degrees even more. Ukmo and gfs say no after Saturday even then only up to 25 or 26. I think Thursday and Friday will be the best days of the week. It's down hill from then :(

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A breakdown of ecm temps which illustrates once again a large geographical variation

Friday - generally quite warm over the whole of Britain with temps generally around 24C, perhaps 26C in places.

Saturday - the main heat area SE of a line Humber to Dorset where temps are around 26C, perhaps the odd 28C. North west of that line progressively cooler and only 12C in NW Scotland.

Sunday - Generally the hottest day but again the highest temps south east of a line Bristol to the Wash with temps in some places 28C, perhaps 30C in some places. In the north a marked contrast with temps 12C -20C.

Monday - the SE hanging on to some high temps 26C, possible 28C with the rest of the country slipping back to 22C - 12C

 

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Further to the above the main convective outbreak crosses the north of England and Scotland late Sunday early Monday and during Monday further smaller outbreaks filter north from Iberia and by Tuesday these outbreaks are pretty general over England  This channel north for the instability is encouraged further by the HP building to the W/SW blocking inroads from the Atlantic trough. This is very much at odds with the previous run so the jury is still out on developments next week.

ecm_mslp_uv850_eur_10.thumb.png.e90ccbc00db0411a06e90480f75ad4a9.png

The EPS mean is more in favour of the previous run.

Edited by knocker
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1 hour ago, Frosty. said:

I think we are still on for 30-32c during the weekend as our high drifts east into the north sea and we import increasingly hot and humid continental air up and across the uk with scorching sunshine and a growing risk of T-Storms breaking out..and it's not even summer yet!:D

better name! still feel though it's too early in year for 30°, 25° will do though, decent warm temps, Thurs/Fri look warmest here 24°, Sat at 23°

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I think its still far too early to say exactly how warm/hot and how long it will last. The MetO forecast this morning still saying highly uncertain to exact details on this weekend - if the GFS/UKMO/ECM runs are all showing slightly different outcomes, then that seems fair to me. Either way it's going to be warm! ECM is a belter today, but perhaps a slightly warmer solution.

gefsens850london0.png

In the short to mid term the GFS 00z op was a bit of a colder outlier, there are plenty there supporting ECMs take on things. Just wait and hold tight folks! :)

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I don't get why the GFS is so massively underplaying the temps on Saturday:

Rhgfs1054.gif

21-23c in the SE with 850s at 13c, no cloud and no rain? Erm, yeah ok then....even parts of france under 16c 850s are shown as 25c. So, so wrong it's unreal.

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