Model Output Discussion

[Nick B]

A damn good analysis as always by GP. In other words, if I read correctly, strong possibilty of a general warm-up going from 7-10 days onward, drawing warmer air from the south (possibly may mean some imported plumes given recent occurences?).

[johnholmes]

At T+240 on the 00z runs from GFS and ECMWF both have an upper trough over the country but with quite different orientations.

GFS is largely west-east with an upper ridge and its surface high beneath it in the Svalbard area.

ECMWF has its upper ridge, less marked, further north west with a marked upper trough and surface feature from just east of Svalbard down into SW Eire.

I’m not one to keep or be able to remember what either showed on the previous 12z outputs but the 00z would lead to rather different temperature levels for the whole country, especially the further NW one lives. Equally the weather would look to be more unsettled on the ECMWF version.

At the 6 day interval using the NOAA checks, the furthest out they do them for the overall 500mb northern hemisphere pattern GFS has improved dramatically and is level with ECMWF. Just how this may reflect at 10 days or indeed on how either will have shown to perform at 10 days from now is anyone’s’ guess in my view. The long term form horse would support ECMWF as being consistently better at 6 days than GFS, but as the link below shows the models do chop and change at times in their accuracy. Nor do I have any idea which synoptic pattern they are better at. Any ideas folks?

http://www.emc.ncep..../html/acz6.html

So what weather we are receiving come 10 days time is uncertain in my view other than fairly unsettled and no heat wave around even for the far south east.

based on the 2 charts I've quoted.

Edited June 30, 2011 by johnholmes

[Weather Boy]

Regarding the possibility of a return of the heat, Rob McElwee makes some interesting comments in his long-range forecast for the BBC.

http://news.bbc.co.uk/weather/forecast/10209

In particular: "It isn't possible to forecast a heatwave more than seven days in advance. But the pressure pattern conducive to summer heatwaves is forecastable much further in advance. Bearing that in mind, over the next four weeks we see such a pressure pattern more than once, so it's fair to say that another heatwave is possible."

I'm obviously not qualified to contradict Sir Rob, but it seems to me that I can see the logic in what he says. The models have a general rule of thumb of not being particularly accurate beyond trends of c. 7 days. Only in that time frame would it be possible to predict air masses' situation so accurately, that you could say with any confidence that there was going to be a heatwave. After all, a relatively small shift could scupper it quite easily, so hard to see how you could predict beyond 7 days.

On the other hand, it may well be possible to virtually rule out a heatwave much further ahead, if the trends and synoptics don't support that as a possibility. I say 'virtually' because of course the models could simply be completely wrong at that range. It sounds that both what Rob and GP are saying is that the trends indicate that further heat is possible, but of course that is only one of a range of possibles.

We know that there won't be a heatwave in the coming 7 days. Beyond that, it's possible and could well happen, but it's too early to say.

[Downpour]

Regarding the possibility of a return of the heat, Rob McElwee makes some interesting comments in his long-range forecast for the BBC.

http://news.bbc.co.u.../forecast/10209

In particular: "It isn't possible to forecast a heatwave more than seven days in advance. But the pressure pattern conducive to summer heatwaves is forecastable much further in advance. Bearing that in mind, over the next four weeks we see such a pressure pattern more than once, so it's fair to say that another heatwave is possible."

I'm obviously not qualified to contradict Sir Rob, but it seems to me that I can see the logic in what he says. The models have a general rule of thumb of not being particularly accurate beyond trends of c. 7 days. Only in that time frame would it be possible to predict air masses' situation so accurately, that you could say with any confidence that there was going to be a heatwave. After all, a relatively small shift could scupper it quite easily, so hard to see how you could predict beyond 7 days.

On the other hand, it may well be possible to virtually rule out a heatwave much further ahead, if the trends and synoptics don't support that as a possibility. I say 'virtually' because of course the models could simply be completely wrong at that range. It sounds that both what Rob and GP are saying is that the trends indicate that further heat is possible, but of course that is only one of a range of possibles.

We know that there won't be a heatwave in the coming 7 days. Beyond that, it's possible and could well happen, but it's too early to say.

INteresting update from Sir Rob. Pretty bullish for the SE again. Is our two nations summer set to continue? Lovely day in London again today.

Monday 4 July 2011 to Sunday 10 July 2011

Westerlies prevail

Although the south of the UK will have a tendency to bask in warm and settled weather, for most, it will be back to the familiar scenario of a westerly breeze with "sunshine and showers or longer spells of rain". No significant departures from the July averages are likely.

Monday 11 July 2011 to Sunday 24 July 2011

Northwest southeast difference

In summer the jetstream should encourage high pressure over us rather than low pressure and it appears that it will try just that during these two weeks. This might set up a heatwave but even if it doesn't it looks like the southeast of the UK will enjoy warm and often sunny weather, and the northwest cloudier, cooler and wetter conditions.

[shedhead]

Mr Mc was also pretty bullish about very cold weather extending into January this year as I recall, but he was quite wide of the mark there in reality. Looking at the 500mb pattern at T+240hrs I still don't see any signs

of the ingredients required to give heatwave conditions in the UK, indeed the longer range GFS tends to suggest few if any major changes to the June pattern, but there will no doubt be some decent spells

similar to the up coming one to look forward to as we pass through July.

[SP1986]

It seems to me in many cases, the northwest south east split, means on the southeast side; England and Wales, and on the north west side; Scotland and Northern Ireland. This is a very normal pattern though, and don't think it needs the term as such.

A west/east split would be far more newsworthy.

[Downpour]

Mr Mc was also pretty bullish about very cold weather extending into January this year as I recall, but he was quite wide of the mark there in reality. Looking at the 500mb pattern at T+240hrs I still don't see any signs

of the ingredients required to give heatwave conditions in the UK, indeed the longer range GFS tends to suggest few if any major changes to the June pattern, but there will no doubt be some decent spells

similar to the up coming one to look forward to as we pass through July.

He isn't actually forecasting a heatwave though – and nor do I understand why people crave them. They are pretty unpleasant unless you happen to be off work and close to a swimming pool.

[95 Degrees]

He isn't actually forecasting a heatwave though – and nor do I understand why people crave them. They are pretty unpleasant unless you happen to be off work and close to a swimming pool.

Some like the heat and are good with dealing with it , and some don't and can't bear it, not that hard to understand really.

[mushymanrob]

thanks for the in depth analysis, it helps us with less knowlege to learn more

obviously im looking towards a possible proper hot spell, its been 5 years now and the models arent a million miles away from a possible hotter evolution sometime in the next 6-8 weeks. i feel that we are closer this year then we have been for some time, so the info posted by jh, gp, etc is of great use as it keeps us (me...lol) from getting up false hopes.

[Mark Burton]

thanks for the in depth analysis, it helps us with less knowlege to learn more

obviously im looking towards a possible proper hot spell, its been 5 years now and the models arent a million miles away from a possible hotter evolution sometime in the next 6-8 weeks. i feel that we are closer this year then we have been for some time, so the info posted by jh, gp, etc is of great use as it keeps us (me...lol) from getting up false hopes.

With the right airmass over us, it very quickly got up into the low 30's C on Monday - so it could happen again with the right set up.

For me, I like the scenario that we are expecting for the weekend, Monday was too hot to work in - this summer could be SO much worse as many older members will testify to. I remember some complete washout holidays in the early 1970's, in the South - totally miserable.

Edited June 30, 2011 by Mark Burton

[95 Degrees]

Agree with whats been said above by other members, like Mushy said there may not be many sign of Hot weather in the short term, but we should enjoy the upcoming pattern suggested by the three main models, with average/slightly above average temperatures and sunshine for all, so although some more naive members may go it's not Hot enough, wheres our 'shades of 76' summer etc, this is a pleasant pattern at the moment which we can't complain about and we should enjoy it because it could be much worse.

[Iceni]

Hi GP

As a new and relatively inexperienced member, could I please ask that when you do an update such as the one above, can you simply conclude in lay mans terms what your thoughts mean for this part of the world.

Something along the lines of...... the above should result in drier, warmer conditions, with LP to the west meaning more of a southerly flow.

I'm sure to many on here drawing a conclusion from what you post is obvious/easy, but there must be others like me that would welcome a greater degree of clarification via a simple one liner.

Cheers

Tony

But which part of the world? Get your location into your avatar and we'll be able to help.

Agree with whats been said above by other members, like Mushy said there may not be many sign of Hot weather in the short term, but we should enjoy the upcoming pattern suggested by the three main models, with average/slightly above average temperatures and sunshine for all, so although some more naive members may go it's not Hot enough, wheres our 'shades of 76' summer etc, this is a pleasant pattern at the moment which we can't complain about and we should enjoy it because it could be much worse.

Just over on the Strat watch thread, there's major warming taking place — a thing of joy and beauty in the winter for snow and cold lovers, but not really what you want for summer heat.

[conor123]

In the shorter term an increasingly warm weekend and then 24-26c for many by Monday is seeming likely with a potential for thundery/convective showers as it breaks down Tuesday onwards.

[mushymanrob]

In the shorter term an increasingly warm weekend and then 24-26c for many by Monday is seeming likely with a potential for thundery/convective showers as it breaks down Tuesday onwards.

...thats assuming theres not much cloud cover, i say this because our regional outlook did (last night) suggest a rather cloudy weekend...

im hoping the pressure builds and the atlantic trough doesnt get here... but thats hopecasting!

[Swave Snow]

But which part of the world? Get your location into your avatar and we'll be able to help.

Just over on the Strat watch thread, there's major warming taking place — a thing of joy and beauty in the winter for snow and cold lovers, but not really what you want for summer heat.

Just been there, its only Mr Data commenting, it doesn't say a major warming taking place. In fact there is very little activity in that thread since the winter

[Evening thunder]

Just over on the Strat watch thread, there's major warming taking place — a thing of joy and beauty in the winter for snow and cold lovers, but not really what you want for summer heat.

Is there? looks like just slightly above average to me. http://ds.data.jma.go.jp/tcc/tcc/products/clisys/STRAT/html_e/pole30_n.html

looks like about 2C above normal to me..

I'm not as knowledgeable as some like chionomaniac for example, but surely a 2C above normal temperature will not have much of an effect. I might be wrong but I thought major warmings only really happened in winter?

On a different point I've noticed runs like the GFS seem to have gradually upgraded 850hpa and surface temps for this weekend/early next week. the 10C 850hpa line comes across the south briefly now.

[Thundery wintry showers]

I don't think this will be a "cloudy" high by any means, but it will be weak enough to allow some convection to sprout up, leading to broken cloud and sunny intervals, and a wide scattering of showers (most places staying dry though). Some areas of the country might end up with relatively cloudy afternoons due to the old issue of convective cloud encountering a cap and spreading into stratocumulus, but I'll be surprised if any lowland areas (bar perhaps Shropshire, which sounds like it's particularly prone) have three cloudy afternoons out of three. So, don't expect wall-to-wall sunshine, but don't expect anything approaching anticyclonic gloom either.

Edited June 30, 2011 by Thundery wintry showers

[Stormyking]

Not a bad looking GFS for the up coming weekend, looks as though high pressure is pushing in and looks to be warm and settled for much of England, Wales and parts of scotland

Temperatures look to be in the range between 22- 26c for a good majority of britain apart from the far North west of Scotland by the looks of it.

Into next week looks quite interesting as low pressure pushes in over us and looks to show potential of Heavy and potentially thundery showers for much of the country by the of it.

I dont really know what to make of FI to be honest apart from it looks quite average but with a lot of low pressure over us or close by but thats FI and will likel keep changing

Lots of Summer still to go so here is hoping to more spells like we just had

[Alex]

Upto until Tuesday we are pretty much guaranteed at least some decent spells of sunshine however you can't rule out a shower anywhere particularly towards the far northwest. From then on the trough unfortunately looks like taking control however it doesnt look particularly mean so I would say a more showery spell is likely with probably some brighter spells the more southeast you are. Something to point out is that if the Azores ridge pushes north east enough it would limit the showers in southern and particularly southeastern areas. Looking at the models from next week I see a bit of June just gone and also a bit of May where the trough isn't strong enough to influence southern areas significantly. Into FI and it's all to play for, I'm not sure you can make a broad forecast where the teleconnections are changing and the detail is slightly changing from each run however on the 12z I would say continuing rather unsettled but changeable in the south.

[snowingman]

Statistics for Northern Ireland

Summer month 1 - JUNE 2011

Dry days 0 /30 - Yes it has rained here every day!!

Rain days 30/30

Days with temp >20C 1/30 - 3rd June

Days with sunshine >5 hrs 1/30

Days with night temp <10C 15/30

Basing this on past 5 years - this ranks the WORST JUNE in 5 years. The GFS outlook is ok for this weekend then more of JUNE weather AFTER 5 days. Absolutely nothing in forecast for any dry or temperatures above normal.

It does annoy me continually when this forum is full of people who live south of Reading. You guys have it real good - so stop whining please.

[Eugene]

Looks very slack to me, if those lows move in i only expect scattered showers and warm sunshine given i missed out on the last setup that looked similar in June i think i`'ll escape with temps around 20C again and hardly any showers.

There is a real lack of proper cool wet windy days this summer with strong winds and wet overcast days with temps down to 14C, cant see any weather on the horizon offering any of that.

The 546 dam line is now retreating northwards for its usual July hiatus, warmer airmasses starting to take over just to our northwest so even cool looking setups just wont have the cool airmasses to tap into anymore, cool looking setups dont deliver the coolness that the same setups deliver in June especially the first half when the 546 dam line is nearer our shores.

[ANYWEATHER]

Looks very slack to me, if those lows move in i only expect scattered showers and warm sunshine given i missed out on the last setup that looked similar in June i think i`'ll escape with temps around 20C again and hardly any showers.

There is a real lack of proper cool wet windy days this summer with strong winds and wet overcast days with temps down to 14C, cant see any weather on the horizon offering any of that.

The 546 dam line is now retreating northwards for its usual July hiatus, warmer airmasses starting to take over just to our northwest so even cool looking setups just wont have the cool airmasses to tap into anymore, cool looking setups dont deliver the coolness that the same setups deliver in June especially the first half when the 546 dam line is nearer our shores.

Well if you look at the projected temperatures over the coming nights it looks pretty cold away from towns and Cities, and if youre going camping like I am Im going to need my Duvet!

[Summer Sun]

Well I am now back from Great Yarmouth tanned and burnt, am I right in thinking we have a nice weekend coming up followed by a breakdown by Tuesday.

[Gibby]

UKMO tonight shows the next 4 or 5 days as mostly dry and fine as High pressure hangs on over the UK once arriving tomorrow. Never very warm but pleasant conditions with a lot of cloud at times. By the end of the run Atlantic Low pressure has reached our shores bringing a spell of rain followed by showers in the south by 144hrs.

GFS also shows a dry weekend but as we go into next week Low pressure moves in from the west and anchors itself over Northern Britain for the rest of the run keeping unsettled conditions with rain and heavy, thundery showers for all areas from next Tuesday on.

ECM follows a similar path with dry, benign weather from now till Tuesday with large amounts of cloud, dry weather apart from a few light afternoon showers as weak High pressure covers the UK. Through next week pressure is shown to fall with rain spreading NE on Tuesday night to be followed by sunny intervals and heavy showers on Wednesday as Atlantic Low pressure becomes slow moving over NW Britain. Thereafter, Low pressure remains anchored over the UK with widespread heavy and thundery showers and relatively cool conditions right to the end of the run.

After the next 4 or 5 days of relatively high pressure holding over the UK all three models are indicative of a shift to Low pressure based weather from Tuesday of next week. GFS and ECM show an unseasonable and potent Low pressure becoming slow moving near the UK giving many days of sunny intervals and heavy showers with hail and thunder on most days locally. Coastal regions in the west and south may not fair too bad at times where winds blow directly off the sea. Temperatures would be near normal but cool in any persistantly showery zones.

[damianslaw]

A fairly settled picture in the main for the next few days- with a weak ridge of high pressure building over the country but eventually becoming squeezed both from the west and the east. By Tuesday all models in agreement that the trough will move into the west of the country bringing wet weather and windier cooler conditions. However, it does look like a rather slack low pressure - so showery conditions rather than wet for many- but these showers could be very slow moving. Temps average at best.

Nothing to really grumble about- indeed a pleasant outlook for many, preety standard british summer fare. I'm off to London this weekend and then sw/w wales for 10 days - hoping to see some lengthy settled conditions. Will have to wait and see.