Model Output Discussion 12z 10/05/13

[Frosty.]

And I cannot understand why you and Gavin keep posting dreamy like summer weather when we are altumately

I think it's because this spring has been so poor and some of us want fine and warm weather for a change, whether the gefs is right or wrong, this god awful pattern will end pretty soon as the pool of cold air to the north shrinks away and the arctic summer arrives, and the azores high is probably going to have a lot more influence than last summer.

[Frosty.]

It's not a case of wanting the cool unsettled pattern to continue, it is simply giving an appraisal and reading between the lines as to what might be the right solution .  We have seen attempts for the Azores/atlantic High to move in with a less amplified jet stream before and whilst it may eventually happen (and afterall no pattern lasts forever) it has proved very stubborn for a long long time now.

 

It could well be that the GEFS ensembles are simply being too quick to try to change the pattern. A lot can happen anyway from a weeks time which still leaves us in the last few days of May. At this time I would trust the ECM to have a better handle, at the very least, in terms of the timing of any improvement (if/as/when it comes).

 

I think most of would welcome some pleasant sunshine at long last, but we still have to give a balanced and realistic view as to when that might arrive

I agree Tamara but if there are models showing fine and warm weather, I will keep posting them. I try to bring a balanced view on here and am trying to shine a bit of light in the darkness which has summed up spring so far, we could be looking at a much better June overall.

[weather_it_will]

whether the gefs is right or wrong, this god awful pattern will end pretty soon as the pool of cold air to the north shrinks away and the arctic summer arrives, and the azores high is probably going to have a lot more influence than last summer.

Keep dreaming.

[Milhouse]

And I cannot understand why you and Gavin keep posting dreamy like summer weather when we are  left with the opposite! With respect to your posts, everytime I come on here we are constantly looking at high pressure charts! Its all fantasy island im afraid and as I said last night I don't see any prolonged settled spell, anyway excuse the rant!!

If we had an easterly popping up for the last few frames of the ECM in December would you expect people to be talking about the mild stuff to come before it.

 

ECM once again throws in a lovely finish with a strong ridge of high pressure to the southwest of the UK. The mean will no doubt support a pressure rise in FI but i await positive developments closer to the reliable timeframe.

Edited May 21, 2013 by Milhouse

[ANYWEATHER]

I think it's because this spring has been so poor and some of us want fine and warm weather for a change, whether the gefs is right or wrong, this god awful pattern will end pretty soon as the pool of cold air to the north shrinks away and the arctic summer arrives, and the azores high is probably going to have a lot more influence than last summer.

Yes, but the models, looking at the trends are not showing anything resembling summer. Of course there will be variations and localized events and summerlike weather will be had for some even during this period!  

[Frosty.]

Keep dreaming.

At least I bring some balance rather than relishing cool and unsettled weather as you seem to do.

[ANYWEATHER]

If we had an easterly popping up for the last few frames of the ECM in December would you expect people to be talking about the mild stuff to come before it.

 

ECM once again throws in a lovely finish with a strong ridge of high pressure. The mean will no doubt support a pressure rise in FI but i await positive developments closer to the reliable timeframe.

Of course, but ecm along with other models show high pressure at the end of there runs!!  

At least I bring some balance rather than relishing cool and unsettled weather as you seem to do.

Ummghh. Just talking reality!  

[Methuselah]

I think it's because this spring has been so poor and some of us want fine and warm weather for a change, whether the gefs is right or wrong, this god awful pattern will end pretty soon as the pool of cold air to the north shrinks away and the arctic summer arrives, and the azores high is probably going to have a lot more influence than last summer.

I agree with that, Frosty...Although it's none-too-warm just now, there have been many fine summers that have been preceded by similar Aprils/Mays...If any of us could reliably predict June's, July's and August's weather, from this early in the season, they'd be millionaires ten-times-over!

[Tamara]

I agree Tamara but if there are models showing fine and warm weather, I will keep posting them. I try to bring a balanced view on here and am trying to shine a bit of light in the darkness which has summed up spring so far, we could be looking at a much better June overall.

I know you do, and that is welcomed by most I would think   We all have our own interpretations and that is a good thing in many ways. June is still the best part of 10 days or so away, so every chance that some better weather may be around the corner hopefully. However, I do wonder about changes to the jet patterns that are seemingly more and more predominantly meridional, and are pulling energy and upper cold pools south eastwards these days rather than to the north east away from us as we were so used to seeing.

[Thundery wintry showers]

The GEFS ensemble mean is indeed remarkably consistent with this morning's set, with the high pressure ridging up towards north-western Scotland and keeping the weather dry and settled.  June 1988 had a very similar setup:

http://www.wetterzentrale.de/pics/archive/ra/1988/Rrea00119880610.gif

http://www.wetterzentrale.de/pics/archive/ra/1988/Rrea00119880614.gif

http://www.wetterzentrale.de/pics/archive/ra/1988/Rrea00119880622.gif

The stats for June 1988 illustrate the main issues with it, though.  It was a dry month (taking the UK as a whole, June 1995 was the only significantly drier June since then) and many parts of Scotland were sunny and warm, albeit not remarkably so.  However, many eastern and central parts of England had a marked shortage of sunshine and below-average daytime maxima, and in East Anglia the shortage of sunshine was comparable to that during June 2012.  These stats reflect the stratus that often comes well inland off the North Sea when the high ridges up to the NW and pulls in north-easterly winds.

 

I can understand the desire to latch onto any hope of a warm dry sunny spell but the problem is that some posts have hyped up the GEFS ensemble mean as a setup that would bring warm sunny weather, when for a significant slice of the country it would probably be neither warm nor sunny.

 

Meanwhile the ECMWF supports the low pressure area sliding across the country at T+144-168 although it makes rather less of the feature than the GFS, and it gets out of the way rather sooner- I think the ECMWF, with its middle-ground solution, is likely to be nearest to the mark (as is often the case).  As for the FI outputs, to me it looks like the HP would not be close enough to prevent weak fronts from influencing the British Isles around its NE flank, although rainfall amounts would almost certainly be small.

 

I am not trying to completely dismiss the potential for something dry, sunny and warm, because when we have the Azores High ridging this close to the British Isles, it only takes a small north-eastward correction of the pattern to bring an extended fine spell of weather, as happened for instance around the 21st June 1995 leading into that summer scorcher.  However as it stands, the only model outputs that look likely to bring widespread conditions that are both sunny and dry this side of T+192 are those from the UKMO operational run and there is nothing particularly warm for the eastern half of the country in particular.

Edited May 21, 2013 by Thundery wintry showers

[Milhouse]

Point taken TWS but the GEFS ensembles look decent with the op on the cool side of the mean for much of the run. Admittedly it looks like a NE flow is favoured but with warm uppers it will feel warm the further you go from the north sea.

 

June 1988 was actually above average temperature wise. 0.9c warmer than last June.

 

[Frosty.]

 

I am not trying to completely dismiss the potential for something dry, sunny and warm, because when we have the Azores High ridging this close to the British Isles, it only takes a small north-eastward correction of the pattern to bring an extended fine spell of weather, as happened for instance around the 21st June 1995 leading into that summer scorcher.  However as it stands, the only model outputs that look likely to bring widespread conditions that are both sunny and dry this side of T+192 are those from the UKMO operational run and there is nothing particularly warm for the eastern half of the country in particular.

Summer 1995 was epic, actually it was too good because a lot of reservoirs nearly dried up, a long hot summer would be just the tonic after this abysmal spring. i'm optimistic about this summer once that residual cold pooling to the north shrinks away and the short arctic summer arrives.

[bluearmy]

the ens spreads on ecm 00z and gefs 12z both take lower heights se just west of the uk days 6 to 8. given the operational 12z runs in general and i rather doubt the ukmo 12z will be right. looking at low res gfs op and gefs post day 8 will be unlikely to give you too much of a steer if we keep getting the trough resetting on its journey to nw europe.  tbh, the only surprise tonight is the fact that gfs op has managed to pick the energy headed se at such a range !  if it weren't for the 12z gem, i would be completely dismissive of the chances of the trough not being back next week. however, we need to see consistency on the ops of a better outlook and we just cant get there.

[Frosty.]

the ens spreads on ecm 00z and gefs 12z both take lower heights se just west of the uk days 6 to 8. given the operational 12z runs in general and i rather doubt the ukmo 12z will be right. looking at low res gfs op and gefs post day 8 will be unlikely to give you too much of a steer if we keep getting the trough resetting on its journey to nw europe.  tbh, the only surprise tonight is the fact that gfs op has managed to pick the energy headed se at such a range !  if it weren't for the 12z gem, i would be completely dismissive of the chances of the trough not being back next week. however, we need to see consistency on the ops of a better outlook and we just cant get there.

we will get there, have faith.

[phil nw.]

Good discussions this evening with differing views reflecting the differing outlooks by the models.

The outputs have been wrestling with this upper trough v Azores high placement for a number of days now and so it goes on.

The mean outputs still show a continuation of a nw-se flow into next week but with transient ridging and as others have said the real settled conditions remain beyond the reliable.

I do think though that with the Azores high lurking this setup is primed for more widespread Summer like conditions once the upper trough shallows out as the remains of the Polar vortex continues to contract.

The GFS run may be premature on this but it`s the type of tweaking to the pattern that`s quite possible as we enter June.

Edited May 21, 2013 by phil nw.

[Gibby]

Hi folks. As I'm a little late tonight and time is tight here is a somewhat shorter review of the 12 noon outputs from GFS, UKMO, GEM, NAVGEM and ECM for tonight Tuesday May 21st 2013.

 

All models show a strengthening Northerly flow over the UK in the coming few days with some unseasonably cold air sinking South over Eastern Britain. Accompanying this coolness will be a rash of heavy showers or more prolonged rainfall most prevalent in the East and SE on Friday. By Saturday and Sunday the winds will have moderated with a slacker NW flow with dry weather with sunny spells for many and just scattered showers here and there.

 

GFS shows unsettled, wet and windy conditions returning quickly as Low pressure slips down over western Britain with 2-3 days of cyclonic winds with rain at times for all in rather cool conditions. Gradually pressure rises later next week with the weekend onward becoming dry and sunny as High pressure builds to form a closed centre over the UK with increasingly warm conditions.

 

The GFS Ensembles show a sharp if notable decline in uppers over the next 48 hours before a slow and steady recovery takes hold to bring average conditions if not slightly above by the end of the output. Rainfall will decrease in amounts as the run progresses with the last to achieve this being in the South.

 

The Jet Stream continues to show a Southward moving flow on the end of a flow moving East over the Atlantic then down over the UK albeit not very strong. This weakens and disrupts over the next few days before developing again later next week.

 

UKMO shows a reasonable end to the Bank Holiday as pressure has built from the SW with fine and bright weather for many by then end of the weekend and bank Holiday Monday.

 

GEM shows increasingly dry and bright conditions developing over the latter part of the bank Holiday and beyond as High pressure ridges in strongly from the West.

 

NAVGEM tonight was not available at time of publishing

 

 

ECM shows a better weather day on Sunday as a ridge crosses over the UK. By Bank Holiday Monday a new Low has sent things downhill over the NW which quickly extends to all areas by Tuesday with rain and showers for all as the Low moves ESE over the UK. Pressure builds somewhat behind it returning the weather to a dry and bright mode again before the end of the run.

 

In Summary it's a mixed bag tonight with the NW remaining the direction we have to look for our weather again tonight. With High pressure in the Atlantic making repeated attempts to intersect the consecutive Low pressure areas there are varying degrees of success shown between the outputs tonight. GFS and ECM both show another surge of Low pressure early next week while UKMO and particularly GEM look much more favourable towards bringing fine weather over the UK, something which GFS does catch up on by Week 2 of it's run. It seems the models are currently struggling handling the events beyond this weekend and I expect more twists and turns over the coming days.

[Geordiesnow]

Although as it has been said by TWS, I do find it a bit of ashame the low pressure system looks like its going to be too close to the East coast for much in the way of convective weather to form, shame the coldest part of the Northerly could not come around 6-12 hours later with those cold uppers and strong sunshine, some beefy convection could of developed but it looks more limited with that weather front in the North Sea not being too far away.

 

Could be some quite low maximum's on Friday in Southern and Eastern areas on Friday, temps could barely get into double figures, this is something the GFS is quite good at predicting that even if it over do the minimum temps quite a bit although minimum temps could be quite low for the time of year during the rest of the week if any clear skies do form. 

 

The potential for some gales down the North Sea coasts looks possible so some interesting weather to speak of for sure if albeit not all that spring like. 

[Summer Sun]

ECM ensemble backs the Op for a pressure rise later next week

 

 

[William of Walworth]

Sometimes optimism based conditions (for summer preferrers) develops a bit more quickly than expected.

<hopecasting!! But I do some positive signs just now, for later on>

Edited May 21, 2013 by William of Walworth

[damianslaw]

Oh well this May just can't seem to settle into any particular groove, with day to day changes and shallow features popping up here and everywhere under a rather slack pattern - and the troublesome trough always it seems destined to park itself across the country.

 

The reliable timeframe remains changeable and distinctly chilly for late May, Friday in particular promises to be a very dissapointing day for eastern and southeast parts with suppressed maxima and lots of cloud wind and rain - a day out of place for late May, a period in some years which has delivered some if not the best dry sunny warm conditions of the year - think back to last year for instance.

 

It really has been a very poor spring in terms of temperatures - barely any spring warmth to talk of, and this May is turning into a damp squib - it could still redeem itself but time is running out fast.

 

Looking longer term - there are some positives for those looking for sustained dry sunny warm conditions - the azores high is lurking just to our southwest and heights do appear to be building to our NE, as someone said if such a pattern retains itself the ever weakening polar vortex should in time help to squeeze out the trough and we would then very likely see a link up of both sets of heights.

 

In the meantime it feels like spring has simply bypassed the country this year.

[Milhouse]

Good post Damian. The building blocks are there for a settled start to June. It's just getting low pressure to shift from the near continent that is proving troublesome.

The weekend is looking good for most with temperatures recovering to average values or just below as warmer uppers come down from the north behind the cold pool of Thursday and Friday. But it's following the weekend that the ukmo takes a much more settled route than the gfs and ECM.

[The watcher]

The prospect for a settled start to June has been thought about for over a week now, the signs seem to be pointing in that general direction for the first 2 weeks to be of a settled nature courtesy of a building Azores in our general direction and now the models begin to hint at this. It'll be a tussle for a while as we usually see with the models, but I think the settled outcome is favored at the moment. Just last week the MJO was pointing in that direction with a phase 1 by end of May, although not a very amplified one at that. Of course there is a long while yet to go in model terms, and with a ridging Azores it is all dependent on the energy South and West of Greenland at the time and the movement of energy off the Eastern US Seaboard. Things do look to be slacking off in the Atlantic over the next 10 days too. I would hedge my bets on a settled 1 or 2 weeks to begin June at the moment.

[summer blizzard]

Beauty of an FI, backing from the ensemble mean.

 

[Thundery wintry showers]

Re. Millhouse, indeed, June 1988 was slightly warmer than average as measured by the CET (14.4C) and it was much above average in Scotland, on a par with those of 2005, 2006 and 2010.  I think the point was more that those in eastern and central England who look at charts like those, with a keen NE airflow on the southern flank of a large anticyclone, and expect sun and warmth, are likely to be disappointed.

 

The chart that Summer Blizzard posted probably would bring warm sunshine away from the east coast as we pick up a drier continental airmass from the SE, but there are some rather cool north-easterlies to get through before we reach that part of FI.

 

The key difference at T+120-168 is that the GFS and ECMWF take a low pressure system SE-wards into the British Isles while the UKMO sends it due east to our north and that also helps to encourage the Azores High to ridge into the west, rather than north-west, of the British Isles which would mean less cloud for eastern areas than many of the outputs that we're seeing between T+168 and T+240.  Judging by the ECMWF ensemble mean, the UKMO is not entirely without support on the ECMWF's ensemble set but the majority of runs are sending that sliding low south-eastwards.

Edited May 22, 2013 by Thundery wintry showers

[Guest pjl20101]

And the CPC 8-14 day chart TWS which isn't looking stable at all with one days run looking better than the day before, then worse than the day before. Seems like the trough in Spain is clipping the south and south eastern parts wheras northern and western parts of the country get it generally more settled by this evidence:

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

It does seem very choppy and change type of scenario and like I have said in other posts that the MJO situation will be in my eyes the determining factor.