Model Output Discussion - 15th April Onwards

[AWD]

GFS this morning isnt a bad run If you want some drier and sunnier weather. After a few wet and unsettled days ahead, by Friday it brings in High Pressure from the west which settles things down nicely for the weekend. One of the first dry and sunny weekends for a long time being protracted.

All 4 models bring in a similar dry and settled weekend.

After the weekend there is some divergence between the big 4. GFS goes unsettled by a weeks time, but only briefly as things settle down again mid next week and remain predominetly settled through FI with quite a large High pressure developing over the UK in deep FI

The ECM also goes Unsettled by a week today but this then remains unsettled through the remainder of its run.

The GEM is similar to the ECM in respect that it turns unsettled again a week today but remains unsettled throughout the rest of its run.

So we have a few wet and cool days ahead first before things look favourable for a dry and sunnier weekend. After the weekend all models agree on it turning unsettled again with a rather deep LP in the Iceland area. The GFS then returns us to a more settled regime again whilst the GEM and ECM keep us locked into a wet and unsettled week next week.

If you want some dry, sunny and usable weather then hope the GFS is right!

Just to add however, the GFS was at the top end of Ensemble runs in terms of Pressure, with most runs supporting somewhat lower pressure around next week.

Edited May 7, 2012 by Active Weather Dude

[Summer Sun]

That's more like it from GFS dry and settled for a good part of its run not before time, we just need it to happen now.................

[Terminal Moraine]

That's more like it from GFS dry and settled for a good part of its run not before time, we just need it to happen now.................

On the other hand there's little support from the ensembles for high pressure to last beyond next Sunday and no support either from the ECM which brings in a deep area of low pressure on Sunday night/Monday morning and keeps it unsettled for the rest of the run.

Edited May 7, 2012 by Terminal Moraine

[Thundery wintry showers]

Not much change through to Friday on this morning's outputs, with sunshine and scattered showers on Tuesday, Thursday and Friday and persistent rain spreading in today and into England and Wales on Wednesday (Scotland remaining brighter with showers).

Looking at this morning's GFS, while the ridge of high pressure should settle things down it is by no means guaranteed to be sunny. Two factors that potentially point towards a dry cloudy weekend are the proximity of fronts to the south, and the shallow convection progged by GFS (which has a tendency to spread out into stratocumulus in anticyclonic conditions). Cloud amounts in these anticyclones are notoriously hard to pin down, even 24-48 hours out, but my feeling is that the further east the high pressure gets, the more likely it is that most places will be sunny and dry.

[Cheese Rice]

That's more like it from GFS dry and settled for a good part of its run not before time, we just need it to happen now.................

It looks like any settled weather will be shortlived with lows crashing in towards the end of the run. I wouldn't be at all surprised to see a northerly come mid-may.

Edited May 7, 2012 by Cheese Rice

[Cloud 10]

Another significant rain event looking likely for thursday as another low pressure tracks across

the UK,with a large temperature contrast between north and south.

The weekend looking pretty decent at the moment with maybe a dry day or two if

we are really lucky!

[AWD]

GFS 12z has done a reversal on its 0z operational run. It has moved towards the evolution the ECM and UKMO runs this morning showed in that after a pleasent and dry weekend, next week is looking again rather unsettled and cool, although this far out, how unsettled and how cool is still undecided.

Into FI and it does try to reinsert High Pressure in control but in this run it is all rather flabby and messy with fronts never really that far away from the UK, ( and making inroads into parts at time ) so a lot of cloud would probably be mixed in.

So to summarise a mixed run from the GFS tonight. Unsettled this week, drier and usable weather for outdoor activities at the weekend, probably the first widely dry weekend for a long time. Then next week increasingly unsettled again with wet and breezy weather at times, slowly becoming less unsettled in FI but by no means completely dry.

For warmth and dry weather, definetly not as good as this mornings 0z run, but that was always likely after observing where the 0z run sat in its Ensembles.

Edited May 7, 2012 by Active Weather Dude

[summer blizzard]

No major change in the outlook in my opinion, bar a few settled days which do not look significantly warm, we see a rather cool and wet outlook.

[Summer Sun]

GFS seems to be in line with with the met offices outlook

Next weekend is likely to bring a respite from the recent unsettled conditions. Saturday and Sunday should be mostly dry and bright with sunny spells and just a scattering of light showers mainly towards northeastern areas. These more unsettled conditions look like becoming established across most of the country by early next week, and persisting into the following week

Edited May 7, 2012 by Gavin D

[Geordiesnow]

Any small chance of warm weather that the models were sort of hinting has gone now, some sort of trend for the Azores high to ridge in from the West which may dry things out but at this stage, you have to favour the jet stream to overridge the high and we'll be influenced by low pressure.

The outlook is mixed and actually strangely enough, the areas with the cooler air is likely to be drier and brighter than the areas that will be under the very mild air in the South where it looks very wet.

[Milhouse]

Wouldnt say the chance of warm weather has gone. Infact tomorrow is looking a much better day on the whole with temperatures perhaps touching 18c in the SE according to the Beeb.

The weekend is looking like the best one in ages with temperatures in the mid teens and a lot of dry weather around. Better than the cloud and single figure maxes of the weekend just gone. The key to how long the settled weather lasts is how far south the low pressure gets next week and, following on from that, how keen it is to pull back northwards.

[Summer Sun]

ECM once more tonight shows high pressure building at the weekend

By Sunday low pressure begins to have its say slowy, England and Wales should get away with another fine day

Which leads to the next LP system to make its way in

Edited May 7, 2012 by Gavin D

[bluearmy]

maybe light at the end of the trough filled tunnel with a sceuro height rise in a couple of weeks. lets hope so, though even if it verifies, no guarantee that the troughing to our west would be far enough away to leave us settled.

[damianslaw]

Looks like we will see a shortlived settled spell over the weekend- good timing, but it isn't set to herald any significant pattern change anytime soon. All models are showing a very unsettled outlook as we head well into the middle of the month, with strong heights to our NW and a southerly tracking jet, only one place for the trough to settle and that is directly over the country...what a cruel blow to what can be and in many years is the best month of the year in my book. The only other month that gives May a running is June - lets hope for a change by the end of the month.

[Snowy Easterly]

dear me 18z is a horrible run, we get a chilly northerly next week which will probably result in more frosts, so crops might have to wait even longer to go outside. cold always seems to upgrade in spring but never in winter, typical

[Alex]

Awful run this morning and I just hope June brings a vast improvement, if we have anything like last year during summer then I think alot of people will be rather depressed! Is there any reason why we aren't getting the pattern change we want?

[Summer Sun]

Awful run this morning and I just hope June brings a vast improvement, if we have anything like last year during summer then I think alot of people will be rather depressed! Is there any reason why we aren't getting the pattern change we want?

We will get a pattern change its just when it will happen, as we have found out previous years this sort of pattern has set up late May / early June and hasn't shifted to September, now thats around 3 month, this unsettled pattern started in April so 3 month would give changes around July, it will be interesting to see what happens this summer.

[PubliusEnigma]

We will get a pattern change its just when it will happen, as we have found out previous years this sort of pattern has set up late May / early June and hasn't shifted to September, now thats around 3 month, this unsettled pattern started in April so 3 month would give changes around July, it will be interesting to see what happens this summer.

Gav pattern changes don't run for a period of three months and then change.. Moreover the pattern which is established in May tends to last thru until the end of August.

And if I were a betting man. The wet April was really not part of the pattern, and more of a bonus, as its topped up our reservoirs and rivers. My bet would be a continuation for for the next four months of this weather, following the absurdly wet April. At last we have a more mobile westerly flow for the foreseeable future. Whilst it will often be dull and wet for most of the time, the raw cold from last week will have gone so at least we should see temps topping out in the mid teens rather than in single digits like last week. The rest of europe will be loving it though as away from the channel and north sea. All other areas should bask in warm summery weather. Its the price we pay here in the UK, for the heat on the continent. At least we should see less in the way of torrential thundery downpours which caused such high rainfall totals in April.

[Frank Trough]

Gav pattern changes don't run for a period of three months and then change.. Moreover the pattern which is established in May tends to last thru until the end of August.

And if I were a betting man. The wet April was really not part of the pattern, and more of a bonus, as its topped up our reservoirs and rivers. My bet would be a continuation for for the next four months of this weather, following the absurdly wet April. At last we have a more mobile westerly flow for the foreseeable future. Whilst it will often be dull and wet for most of the time, the raw cold from last week will have gone so at least we should see temps topping out in the mid teens rather than in single digits like last week. The rest of europe will be loving it though as away from the channel and north sea. All other areas should bask in warm summery weather. Its the price we pay here in the UK, for the heat on the continent. At least we should see less in the way of torrential thundery downpours which caused such high rainfall totals in April.

is that really true? it is more likely than not in any given year that the pattern established in May lasts until the end of August? or do you just mean more likely for certain pattern types?

Anyway, that aside, after a couple of dry days over the weekend the outlook after that continues to look awful. There's no denying that.

[Thundery wintry showers]

This week remains similar to how it was progged a couple of days ago- sunshine and showers today, rain in the southern half of Britain tomorrow, though on Thursday the persistent rain hangs around in northern England instead of clearing to leave sunshine and showers. Sun and showers for all on Friday, the showers heaviest in the north-east (although I imagine my location will somehow contrive to miss all the showers on the showery days again- lol)

The high pressure over the weekend looks set to give a bright and mostly dry day on Saturday, though there will still be a few isolated showers about, and convective cloud spreading into stratocumulus giving a cloudy afternoon is certainly a possibility. Sunday will be a similar story in southern parts of the country but with rain spreading into the northern half late in the day, so just a temporary ridge of high pressure really. GFS, UKMO and ECMWF all show this scenario.

Next week is looking distinctly changeable- the Azores High shows signs of establishing in its traditional position but unless we can get height rises into western Europe the end result of that will tend to be an onslaught from the Atlantic. The nature of next week's changeable weather, though, is prone to considerable change at this time range.

[Alex]

Gav pattern changes don't run for a period of three months and then change.. Moreover the pattern which is established in May tends to last thru until the end of August.

And if I were a betting man. The wet April was really not part of the pattern, and more of a bonus, as its topped up our reservoirs and rivers. My bet would be a continuation for for the next four months of this weather, following the absurdly wet April. At last we have a more mobile westerly flow for the foreseeable future. Whilst it will often be dull and wet for most of the time, the raw cold from last week will have gone so at least we should see temps topping out in the mid teens rather than in single digits like last week. The rest of europe will be loving it though as away from the channel and north sea. All other areas should bask in warm summery weather. Its the price we pay here in the UK, for the heat on the continent. At least we should see less in the way of torrential thundery downpours which caused such high rainfall totals in April.

I agree that pattern changes don't have a set rule of 3months. However I disagree that Mays pattern sets the tone for the summer,

2011 was dry and warm

In the southeast but summer was wetter and cooler than normal, 2010 was cool and dry, summer was mixed with a brilliant July overshadowed by an awful August. 2009 had a very average May and the summer followed as mixed. 2008 was warm and had a wet finish, the summer was pretty awful. 2007 was similar in being wet and at times cool. 2006 though was very different, a wet may was followed by a scorching summer!

So some similarities but also some variances. It really depends on the Synoptics, my point though was that if we do get an awful summer, I think alot or people will be very disappointed ESP with the jubilee and the Olympics this year! It doesn't set a great example to any tourists either or change the opinion of our awful wet climate that people around the world seem to think.

[johnholmes]

A pdf below to show how the models from last Thursday fared in terms of where the surface low and its depth compared to their predictions.

comparing forecast to actual chart 5 days apart.pdf

[Summer Sun]

GFS 06z ends settled with high pressure building to our east until then its more of the same with a few decent days here and there followed by some unsettled ones

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

[johnholmes]

Gav pattern changes don't run for a period of three months and then change.. Moreover the pattern which is established in May tends to last thru until the end of August.

.

1975?

and I'll put in another pdf as soon as I can about a possible pattern change showing on 500mb anomaly charts

Edited May 8, 2012 by johnholmes

[PubliusEnigma]

I agree that pattern changes don't have a set rule of 3months. However I disagree that Mays pattern sets the tone for the summer,

2011 was dry and warm

In the southeast but summer was wetter and cooler than normal, 2010 was cool and dry, summer was mixed with a brilliant July overshadowed by an awful August. 2009 had a very average May and the summer followed as mixed. 2008 was warm and had a wet finish, the summer was pretty awful. 2007 was similar in being wet and at times cool. 2006 though was very different, a wet may was followed by a scorching summer!

So some similarities but also some variances. It really depends on the Synoptics, my point though was that if we do get an awful summer, I think alot or people will be very disappointed ESP with the jubilee and the Olympics this year! It doesn't set a great example to any tourists either or change the opinion of our awful wet climate that people around the world seem to think.

The thing is Alex, our current weather IS the norm, if you look at averages dating back to the year dot. this is what WE should have facing an ocean at 50-55oN. It is the what it is. Crudely speaking since 2007 there has been a definite trend, of notably warm springs, and even more notably warm/mild autumns. 30oC on 1st / 2nd October 2011 !!

And around 28oC over Easter in 2011. OK so this year the warm spell arrived even earlier in March, in fact I got sunburnt in March !!! 23oC was recorded in a number of places. Could March end up being our warmest month of 2012. I have no idea what is causing the British weather to become seasonally slightly more predictable than the total chaos hitherto. One could argue does the May trend reveal the coming trend for the rest of summer OR is it due to the pressure distribution which seems to have a 'preferred set up' ( as bizarre as that may sound) , that we are to endure endless unsettled weather during the summer months, or what seems to be our rainy season.

I fear the attached FAX could well sum up Summer 2012

I can't see us hitting the 20oC mark this month. We've clocked up about 2 hours of sunshine !! here since the end of April. And all the charts are showing another two days of dull weather on top of todays overcast skies. Just as the southern arm of the jet which is coming up to bash us over the next two or three days runs out of steam at the end of the week, the northern arm then takes aim to continue the relentless run of unsettled weather.

On as aside I seem to recall during the Olympics closing ceremony, the British bid team put on a brief display to highlight the games coming to London, which featued

masses of spinning umbrellas in it. I guess everyone coming here will be expecting rain and cloudy days anyway..

Edited May 8, 2012 by PubliusEnigma