Model Output Discussion 18Z 18/6/13 onwards

[Mark Parsons]

Not to forget the SST 's are below average still which increases the risk of fog on windward coasts, as today so far here in south Dorset, so it may not be nice for everyone if and when any more spells of warm weather arrive on our shores this summer!

[Summer Sun]

Another stunner from ECM this morning

 

 

Ensemble mean is a case of as you were

 

 

10 day precipitation forecast

 

[Methuselah]

Now all we need is a visit from the 25C isotherm...Has that ever occurred before?

[Tamara]

Just about emphatic support from the EPS individual maps for warm High pressure as depicted by the ECM operational this morning. And it has come into a range we can trust with this sort of synoptic at this time of year.

 

I think for most, a range of temperatures from the low to upper 20's C is plenty warm enough, combined with strong sunshine and night time temperatures at quite a warm level. For me it looks ideal as the pattern looks fairly stable and not liable to a quick breakdown within a day or so

 

Very little to complain about I would think. And today is some good practice to enjoy as well

 

[nitro_deluxe]

Now all we need is a visit from the 25C isotherm...Has that ever occurred before?

 38 BC!?

 

Joking aside - any slight pattern shift, could well make for some interesting synoptics, should keep heat lovers more than pre occupied. 

[Mark Parsons]

Another stunner from ECM this morning

 

 

Ensemble mean is a case of as you were

 

 

10 day precipitation forecast

 

Good old fashion British weather then which is just the job, it will be interesting to see if the high orientates in to a southerly flow at some point to bring that heat some crave!

[Frosty.]

Now all we need is a visit from the 25C isotherm...Has that ever occurred before?

would that mean 40 celsius plus ....that's too hot for me but in the usa it's a cool breeze

[Summer Sun]

GFS still shows a low pressure system moving down the country within the t240 range

 

t228 is the last day for warmth in the south

 

 

Cooler air sweeps across the country

 

I've just looked at cloud amounts for this high pressure system it looks quite cloudy for some areas

[Mark Parsons]

GFS still shows a low pressure system moving down the country within the t240 range

 

t228 is the last day for warmth in the south

 

 

Cooler air sweeps across the country

 

I've just looked at cloud amounts for this high pressure system it looks quite cloudy for some areas

on a positive note it is 10 days out though plus we haven't even had the event yet !!

Edited June 30, 2013 by Mark Parsons

[Frosty.]

 we haven't even had the event yet !!

what are you on about? it's a very warm sunny day today and tomorrow will be 22-23c again in the south & east!!

[WheresTheSnow]

GFS showing it becoming warm again by Friday, after a brief cool down at the beginning of this week.

 

24C at 129 hours, happy with that!

Lovely stuff, 26C!

Even better, 27C - might get burnt IF it comes off!

 

Lets hope these come off, and I will not be dancing until Wednesday comes around as that is a much closer/reliable timeframe. Still - promising signs that next weekend will be similar to temps seen today.

[Captain Shortwave]

Much stronger building of pressure over the UK on this run

 

Compared to

[bluearmy]

a spanking ecm op but in a period of inconsistant fi's, operationals post day 6 are worthless. What did catch my eye on the NH ecm day 10 mean output, is the way the axis of hemispheric troughing has shifted from the eastern atlantic to the eastern side of canada. Take a look back a few weeks at the NH profile and you'll see nw europe stuck under that mean lw trough.

Latter stages of ecm ens run also shows the west russian ridge sinking and retrogressing towards the azores ridge. Will we see a mean scandi/n w russian trough? If so, thats unexpected given so many lrf's had high heights to our ne for july.. There are some signals on the fi ops of this evolution with the cooler less settled conditions easing closer to the uk as our ridge returns back west.

[Frosty.]

The Ecm 00z ensemble mean is nothing short of superb, it really is that good, high pressure becomes dominant with temperatures between 25-30c across most of the uk, nearer low 20's celsius for the northern half of scotland and there would also be a risk of a few thundery showers breaking out in the heat of the day but it looks generally fine, sunny and very warm from the end of the coming week onwards.

[Tamara]

a spanking ecm op but in a period of inconsistant fi's, operationals post day 6 are worthless. What did catch my eye on the NH ecm day 10 mean output, is the way the axis of hemispheric troughing has shifted from the eastern atlantic to the eastern side of canada. Take a look back a few weeks at the NH profile and you'll see nw europe stuck under that mean lw trough.

Latter stages of ecm ens run also shows the west russian ridge sinking and retrogressing towards the azores ridge. Will we see a mean scandi/n w russian trough? If so, thats unexpected given so many lrf's had high heights to our ne for july.. There are some signals on the fi ops of this evolution with the cooler less settled conditions easing closer to the uk as our ridge returns back west.

That may be possible I agree eventually. But a good time I think for enjoying the prospect of some fine weather to come first of all. There is excellent cross model support for a fine spell to last several days at least before the type of evolution suggested here

[Mark Parsons]

what are you on about? it's a very warm sunny day today and tomorrow will be 22-23c again in the south & east!!

Obviously i'm on about the latter part of this week when pressure rises again not this blip we are having now and besides that some of us are under murky/ fog off and on at the moment, however I always admire your optimism with the country as a whole...................

[Frosty.]

Obviously i'm on about the latter part of this week when pressure rises again not this blip we are having now and besides that some of us are under murky/ fog off and on at the moment, however I always admire your optimism with the country as a whole...................

Thanks mark, for some areas it's possibly going to be the warmest day of the year so far, maybe 27c, the cooler changeable spell looks very brief thankfully, our first nationwide anticyclonic spell is only a matter of days away and nothing will stop it now.

[Summer Sun]

All is looking very good from the latest met office update

 

UK Outlook for Friday 5 Jul 2013 to Sunday 14 Jul 2013:

 

There is reasonable confidence that high pressure will build, giving fine and dry weather across most parts of the UK from Friday onwards, with a mixture of variable cloud and sunshine. Some glancing blows from Atlantic weather fronts are still possible across far northwestern parts at times, these fronts bringing some cloud and rain with cooler and breezier conditions, mainly western Scotland and perhaps Northern Ireland. Lighter winds elsewhere with temperatures around or just above normal at first, but a good chance of increasingly warm temperatures during the course of the following week, especially inland, becoming locally very warm in sunny conditions. There is a chance that isolated late afternoon showers may develop inland with this warmth. These drier and warmer conditions should continue into the following weekend.

 

GFS 06z is another high pressure dominated run with any break downs right out in deepest FI (end of week 2 in July)

 

http://www.null/ds/gfs.htm

[draztik]

it looks generally fine, sunny and very warm from the end of the coming week onwards.

in your opinion, and by looking at the models as they are currently, are we looking at a prolonged spell? Or a matter of days? Edited June 30, 2013 by draztik

[Summer Sun]

in your opinion, and by looking at the models as they are currently, are we looking at a prolonged spell? Or a matter of days?

 

Looks fairly prolonged for once

 

[Tamara]

Thanks mark, for some areas it's possibly going to be the warmest day of the year so far, maybe 27c, the cooler changeable spell looks very brief thankfully, our first nationwide anticyclonic spell is only a matter of days away and nothing will stop it now.

Yes I think there is no reason to hold back much caution now, and optimism is fully justified for summer (proper) to be just around the corner - on a more nationwide basis and not an IMBY one.  A change of seasonal wavelengths I think will make a crucial difference now as to how patterns will evolve from here - especially with a totally different polar pressure profile to last year.

[Frosty.]

Yes I think there is no reason to hold back much caution now, and optimism is fully justified for summer (proper) to be just around the corner - on a more nationwide basis and not an IMBY one.  A change of seasonal wavelengths I think will make a crucial difference now as to how patterns will evolve from here - especially with a totally different polar pressure profile to last year.

Spot on Tamara, I can understand why you have been so cautious because we have had our fingers burned many times when believing something that more often than not looks too good to be true, as it often is, but this time, as you say, the optimism is fully justified with all the background signals supporting the pattern change and most crucially, the met office too.

[Frosty.]

in your opinion

Not just my opinion

 

It's impossible for anyone to say how long it will last but I would think the generally very warm and settled spell will last at least a few weeks, there will probably be some disruption along the way but a good chance of a full recovery subsequently, this really could be the major pattern change most of us have been craving.

[chris55]

Haven't posted on here for a while. But ECM caught my eye this morning,

 

Beauty

 

http://www.wetterzentrale.de/pics/Recm1441.gif

[DTHFCJ]

Might be a good idea just to do a quick illustration to clear this one up (I do understand it is confusing with the difference between heights and SLP - getting your head around the different pressure layers of the troposphere is one of the most tricky things to do, but its essential for more expansive forecasting)

 

So, heres a couple of basics, the sort of things that I used to take a look at when I only had a chance to glance quickly at the models. I have made some markings on the below image - the latest height anomaly projection from the ECMWF

 

Height-Anomalies.gif

 

As John has said, ignore the colours for now - follow the lines! (Again its tricky to get your head around, but don't automatically assume that the higher heights (reds) will always lead to high pressure, and vice versa with blues). By the lines, we are talking about the "horizontal" black lines, which are indicated by the green arrows drawn.

 

If anyone can think back to GCSE Maths (or possibly even physics), think of these in terms of a Sine wave. When they point up, they are a peak (or in meteorological terms, a ridge) and when they point down, they are a trough.

 

You might have heard that term trough used a fair bit on here - ridges and troughs are what make up the Longwave Pattern across the Northern (and Southern - though we rarely focus on this) hemisphere. By this, we mean that the weather all around the globe follows a series of ridges (areas of high pressure) and troughs (areas of low pressure).

 

We can identify such areas on the annotated chart above. I have shown a ridge (in the blue box) forecast across the UK - taken in current context, in around 8-10 days time, the current ECMWF suggestion is of ridging across the UK. How can we tell it is a ridge? Because those black bars are pointing towards the north pole.

 

I have also identified a trough (in the yellow box), which would indicate an area of 'troughing' - essentially, an area (or collection) of low pressure. We can tell its a trough because the black lines are facing towards the equator.

 

So, its a case of looking for ridges (black lines facing poleward) for the chance of more settled conditions, and troughs (black lines facing equator-ward) for unsettled conditions. 

 

It gets a lot more complex than that - we can start looking for closed ridges/troughs, and in the winter, we also look at certain colours of the black lines indicating where the 528DAM line (considered a good measure of the 'snow line' under most circumstances) is. But we'll worry about that another day.

 

In the meantime, when looking at height anomaly charts, look for ridges for potential settled spells, and troughs for potential unsettled spells, in the vicinity of the UK

 

SK

Thankyou very much Snowking ...