Model Output Discussion 18z 28/07/13

[Methuselah]

All I can add Frosty is: let us pray! Plenty of potential in today's runs...

[Bristawl Si]

Great stuff if it comes off.

And to think some on here were writing off the rest of Summer - why oh why do people continue to write off summers and winters based on dodgy computer model output?

[bluearmy]

Those of you wondering where ecm op gets its trough position from for next weekend would do well to look at the spreads on the 00z run ( will edit this post to add a thumbnail in a while).

Basically, the 12z op places the depression track where the ens most preferred position was. No certainty that this will be the correct solution but its common for the op to follow the spreads from the previous suite.

[draztik]

Thing is, saying that we are heading towards a hot spell seems to be nothing more than hopecasting at this stage. The models don't show this "hot" weather! HP, even in August, doesn't always correlate with hot weather! If you look at the gfs 12z op, it doesn't show temps in the mid 20s until the 25th!!

if anything we are heading for a very pleasant spell. But hot? Where is the support for that? Even the ensembles don't show it. Above average is all that is shown tonight.

[Captain Shortwave]

Those of you wondering where ecm op gets its trough position from for next weekend would do well to look at the spreads on the 00z run ( will edit this post to add a thumbnail in a while).

Basically, the 12z op places the depression track where the ens most preferred position was. No certainty that this will be the correct solution but its common for the op to follow the spreads from the previous suite.

I'm surprised by that given the mean chart for the weekend showed the main trough over Iceland and the jet passing through northern England

 

I would be interested to see the individual members here though, I'm struggling to see how it could be the case but hey I'm here to learn 

Edit - ECM mean is now further south

Edited August 11, 2013 by Captain shortwave

[Bristawl Si]

Thing is, saying that we are heading towards a hot spell seems to be nothing more than hopecasting at this stage. The models don't show this "hot" weather! HP, even in August, doesn't always correlate with hot weather! If you look at the gfs 12z op, it doesn't show temps in the mid 20s until the 25th!! if anything we are heading for a very pleasant spell. But hot? Where is the support for that? Even the ensembles don't show it. Above average is all that is shown tonight.

Has anyone actually used the term "hot" though?

[Summer Sun]

Has anyone actually used the term "hot" though?

 

Frosty did

 

I really think we are in for a fantastic spell of settled and very warm/hot weather for the last 10 days of August and lasting well into the first half of september.

[MP-R]

Best not to get carried away either way - only a week ago, this weekend was supposed to be warm and sunny with a high of 1025mb gracing the south of the UK. Well, we all know how that turned out. I can't help think that if another warm spell begins around the 20th, it will have nearly been a month since the last spell of high pressure - pretty rubbish for peak summer, and a real kick in the teeth if it lasts well into September as precious time has been wasted since the 1st August and looks like it will continue to be throughout this week. 

 

Moaning aside, while all models show a rather cloudy week to come, it is far from wet and at least temperatures scrape average after a decidely autumnal day to come tomorrow with scattered showers from the Midlands northwards.

[Summer Sun]

ECM ensemble at day 10 looks promising

 

 

GFS ENS for the same time

 

[East_England_Stormchaser91]

Thing is, saying that we are heading towards a hot spell seems to be nothing more than hopecasting at this stage. The models don't show this "hot" weather! HP, even in August, doesn't always correlate with hot weather! If you look at the gfs 12z op, it doesn't show temps in the mid 20s until the 25th!!if anything we are heading for a very pleasant spell. But hot? Where is the support for that? Even the ensembles don't show it. Above average is all that is shown tonight.

From what I am seeing, the weather would certainly be close to, if not 'hot' if they came off. We're seeing 24c now under no more than 10c uppers. 

If them Southerlies came in, it would feel hot, that's for sure.

[Captain Shortwave]

ECM ens have pretty much backed it's operational too a tee. A little disappointed but I still feel the troughs are being dug too far south again, based on how things have gone over previous weeks.

[Frosty.]

Has anyone actually used the term "hot" though?

Yep and I stick by what I said because those mean charts and especially the gefs 12z mean would deliver a very warm or hot and anticyclonic late august spell.

[damianslaw]

Reliable timeframe - position of the jet stream will put pay to the chances of any signficant warm up. It is set to remain on a quite a southerly position, the azores high will influence conditions in the south from time to time, but weakly. Mid 20's maximums best we can expect in sheltered southern parts. Northern part low 20's by end of next week.

 

The outlook is very standard August fayre - can't get more average for time of year.

[J10]

Im sure john could better articulate the anomaly charts, but the HP the models are showing seems to now have anomaly support!

http://www.cpc.ncep.noaa.gov/products/predictions/814day/500mb.php

As nice as these charts are, weekend ones are raw charts and not modified by forecasters. Here's hoping though that tomorrow's charts show similar.

Edited August 11, 2013 by J10

[William of Walworth]

Loving some of these further FI charts that have been posted for the week after next, and my birthday's on Sunday 25th. Then, it looks perfectly capable of being very HP-controlled in FI.

 

But pretty much all I short-termly care about, right now, is low to no rainfall levels from Thursday to Sunday (next weekend) in the SW  -- Exeter area.

 

I am very far from optimitic about that on the most recent projections, with troughs/lows for that next-weekend period looking like they want to dig well South on some (most?) models.

Edited August 11, 2013 by William of Walworth

[J10]

Best not to get carried away either way - only a week ago, this weekend was supposed to be warm and sunny with a high of 1025mb gracing the south of the UK. Well, we all know how that turned out. I can't help think that if another warm spell begins around the 20th, it will have nearly been a month since the last spell of high pressure - pretty rubbish for peak summer, and a real kick in the teeth if it lasts well into September as precious time has been wasted since the 1st August and looks like it will continue to be throughout this week. 

 

Moaning aside, while all models show a rather cloudy week to come, it is far from wet and at least temperatures scrape average after a decidely autumnal day to come tomorrow with scattered showers from the Midlands northwards.

But locally it was a lovely weekend. A lot of sun early Saturday, and more Sunday especially.

 

I know that not all parts did as well, but this was far better here than last weekend's disappointing Saturday, and very Wet Sunday.

[johnholmes]

Julian, its an old chestnut about no forecast input. In my view of watching these over 3 years I am hard pushed to give any credence to changes into or out of the weekend.

In terms of the time scale to what they are showing they go no further, with NOAA, than 15 days; with ECMWF-GFS 10 days. Anyone using them beyond that time scale must be even more careful than during the time scale. They, to me, all of the main 3, I do not use NAEFS simply because I have no first hand knowledge, unlike with the other 3, of how well or not they perform. Those 3 have consistently shown an upper trough for days on end now, they predicted this change well, and I see nothing in any of the 3 to be able to say they are changing yet. They may do, but I do not tend to suggest any change until all 3 have got the same or very similar change showing after at least 2 and usually 3 days. So far there is nothing to show any marked change. The anomaly part of the charts shows nothing of any substance near the UK, 30DM is neither here nor there, particularly in the middle of a sizeable upper trough with a strong 500mb flow across the Atlantic. Beyond 15 days then I do not pretend to have a great deal of knowledge at that distance.

 

ps 

the only slight change is in the direction of the upper flow into the UK, that is a bit further back, almost south of west which may (note the word) may be the start of a shift in the wavelength.

Edited August 11, 2013 by johnholmes

[MP-R]

But locally it was a lovely weekend. A lot of sun early Saturday, and more Sunday especially.

 

I know that not all parts did as well, but this was far better here than last weekend's disappointing Saturday, and very Wet Sunday.

 

I hear ya. I'm sure many will wonder what I'm on about. We have had some lovely sunshine here too, but normally before 11am and after 4.30-5pm. Funnily enough, last Saturday 7.5 hours of sunshine is higher than any day this week. 

 

This is the closest chart from the reliable of the GFS 18Z that says to me possible sunshine: http://www.wetterzentrale.de/pics/Rtavn661.png Other than that, a pretty boring week to come. I apologise for my despondent attitude but I just can't see anything inspiring within the reliable.

[summer blizzard]

I do feel that people are being baselessly bullish. Out to day 8 and the pattern is pretty mobile with a transient ridge for the south. After day 8 and the enembles show riding centered south west, hardly a heat wave.

[Captain Shortwave]

I find it ironic that the people who are using the term "heat wave" are those who don't want that to happen.

Where are the models this morning then.

UKMO has a nasty trough just north of Scotland at T144, but then again it showed something worse at T144 yesterday so the UKMO has delayed that low by a full 24 hours showing how reliable that model is beyond day 5.

GFS has pressure rising from the south next Monday. This is also ensemble backed. You can't be too specific apart from the jet moving just north of the UK suggesting high pressure in control and centred somewhere near the UK.

I find it really odd how people can say that any pressure rise is completely baseless given model output and a strong trend shown from the GFS in particular even at 15 days from verification. Again it's the people who clearly want unsettled and cool weather who cherry pick charts from a single op run (usually GFS past 240h where you are better off blindly throwing a dart at a dartboard with weather types written on them)

Yes it may all go the way of the pear, but I don't see the need for such negativity given the output recently. No model is showing relentless Atlantic activity and it's been proven time and time again that the worst the models throw at us is watered down a lot come T0. 

Feel free to have your own opinion is there is some meat to your argument, not any phrase like "the Atlantic always wins", also if we do get a more settled spell developing towards the end of the month, the one phrase I don't want to hear is "that was not expected" like the July spell because that is a very baseless statement 

[The Northern Ramper]

I find it ironic that the people who are using the term "heat wave" are those who don't want that to happen.

Where are the models this morning then.

UKMO has a nasty trough just north of Scotland at T144, but then again it showed something worse at T144 yesterday so the UKMO has delayed that low by a full 24 hours showing how reliable that model is beyond day 5.

GFS has pressure rising from the south next Monday. This is also ensemble backed. You can't be too specific apart from the jet moving just north of the UK suggesting high pressure in control and centred somewhere near the UK.

I find it really odd how people can say that any pressure rise is completely baseless given model output and a strong trend shown from the GFS in particular even at 15 days from verification. Again it's the people who clearly want unsettled and cool weather who cherry pick charts from a single op run (usually GFS past 240h where you are better off blindly throwing a dart at a dartboard with weather types written on them)

Yes it may all go the way of the pear, but I don't see the need for such negativity given the output recently. No model is showing relentless Atlantic activity and it's been proven time and time again that the worst the models throw at us is watered down a lot come T0.

Feel free to have your own opinion is there is some meat to your argument, not any phrase like "the Atlantic always wins", also if we do get a more settled spell developing towards the end of the month, the one phrase I don't want to hear is "that was not expected" like the July spell because that is a very baseless statement

Agreed

There is one member in particular who posts the most unsettled or cool chart he can find,usually every six hours.

[mushymanrob]

well, within the reliable nothings changed... after a couple of cooler showery days temps are expected to rise as muggier west/southwesterlies return. i feel cloud will be a spoiler though, but it should be very nice in any sun.

 

then , after a windy, wet at times, weekend as a deep atlantic trough skirts by, all eyes are on the expected pressure rise. the chances of a pressure rise is i think quite high, but what it delivers us , the detail, is in considerable doubt. we simply dont know as to the nature of the expected high.. its position, the uppers, and its that detail that will make all the difference between us getting something sunny/warm or sunny/hot.

 

take note of what john says about the anomaly charts, hes done the groundwork, the rest of us (most of us i suspect) are playing 'catch up'. im using them because they are moving towards a settled spell developing, but as yet do not confirm an all out high pressure dominance.

 

the pick of the bunch , but its out quite a way, but supports this mornings gfs for around the same period..

 

maybe this chart is heading that way too

 

but these

 

appear to support the ecm (00z) (i expect with subsequent runs the ecm will also show something similar to the gfs as t240 comes into the predicted charts)

 

so there are sound grounds for optimism for something sunnier/warmer and more settled next week... but what the nature of this spell will be is far from certain.

Edited August 12, 2013 by mushymanrob

[The Northern Ramper]

It looks like the models are delaying the weekend poor weather until Sunday and then a pressure rise thereafter.

[Frosty.]

The GEFS 00z mean continues to trend towards a warm and anticyclonic outlook next week and beyond, temperatures would easily reach the mid 20's celsius and probably high 20's c for the south/se. This week also shows pressure rising to the southeast with a fine and warmer spell by midweek towards the southeast, temperatures into the low to mid 20's celsius with the fine spell lasting longest in the far south/se, the northwest of the uk looks pretty unsettled with average temperatures throughout this week with just the occasional fine day and all areas eventually becoming less settled and cooler for a time by the end of this week into the early part of next week as low pressure pushes eastwards across the far north of the uk, but once that low has gone we should be into calmer waters and the azores/atlantic anticyclone looks like building northeastwards across the whole of the uk and strengthening it's grip as time goes on, we are currently on track for a perfect end to summer 2013, a generally exceptionally good summer.

[Frosty.]

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