Model Output Discussion 30/06/2012

[Jason T]

you'll be sure to let us know when there's some good news, won't you?!

Matt Hugo also said the second half of february was going to be very cold due to northern blocking as that was what the ECM 30 dayer was indicating. It wasn't.

I have the sinking feeling he's more likely to be right this time around. the METO further outlook has now delayed any promise of better weather until the end of july as well.

What year.? Got to admit if you want to learn about LP systems the UK model output is the place to view. Is it fair to say from posts's by most of the knowledgeable's that summer just really is not going to happen this year. What do we really need to see in the data and output to break this dire trend.

No doubt this is premature but could we be on the same path for winter 2012/2013 as 2011/2012.?.

JT

[Summer Sun]

There is nothing at all remoting summer tonight again remains unsettled for a while yet

http://www.netweathe...tion=nwdc;sess=

ECM is just as bad

http://www.netweather.tv/index.cgi?action=ecm;sess=

UKMO also stays unsettled

http://www.netweather.tv/index.cgi?action=meto;sess=

[OldMetMan]

There's not much change of any note in the latest model output, only to say the ECM now seems to have fallen in line with other models in keeping LP over or near the UK for the foreseeable future.

As I mentioned the other day, I remain convinced that while the extreme heights (and associated extreme temps) remain entrenched over much of the US, I can see no clear way in which the downstream flow will shift significantly. There do seem to be signs that the US upper high axis is beginning to shift W and the medium term model output suggests more of an upper trough forming over and to the E of the US and Canada, but from our point of view that only serves to amplify the downstream flow with another upper high forming mid-Atlantic, and with a sharper upper trough over us.

In the long term, all the models are in reasonable agreement with changes occurring only slowly, However, the trend seems to be to move the main area of LP over the near continent so I still think we will see HP starting to build from the NW or N, but it may take another 2 weeks or so before it happens. Historically, this is a situation I have seen happen before.

I think it is still important to watch the trends in the Atlantic hurricane season this year as I believe this will have a significant effect on the longer term trends here. At the moment, it has gone quiet but the tropical waves coming out of Africa are showing signs of growing more active and, with the Azores High and the subtropical ridge staying south this would guide any storms on a more westerly course, with the threat of more US land-falling storms than usual. This is bound to affect the flow over the US and thus the downstream flow over the UK – one effect would be to strengthen the flow along the US east coast as any ex-storms carry their hot airmass NE.

In terms of the models, I am keeping an eye on the tropical Atlantic forecasts.

Meanwhile, swirling LP over us – plenty more rain to come – and when the pressure gradient slackens, watch out for big, slow-moving storms.

[Jason T]

Oh Dear..............

July 12…What’s To Be Expected?…

3JUL

Well there goes one summer month, that’s if you can call it a summer month and clearly June has gone down in the record books for various reasons, most particularly in terms of precipitation. I’m sure many were expecting that after the scenes and pictures from various areas of the UK over the last number of weeks, as low pressure brought persistent rain and flooding to parts of NW England and Cumbria and then also the severe thunderstorms late in the month. Overall quite a month, clearly not for the right reasons, but a month which all the medium and long-range models highlighted would be unsettled and clearly it was…

Early July is up and running and as you may have gathered from the shorter range forecasts and information, a change of month hasn’t brought a change in the weather and unfortunately I don’t expect any changes in the near future;

Throughout the first half of July I expect and predict that the predominantly unsettled synoptic pattern will continue. The broader synoptic pattern is likely to maintain a trough across the UK, whilst higher pressure is dominant across Eastern Europe and more importantly to the North-west of the UK. As we have experienced for numerous weeks now, high pressure to the North-west of the UK in summer is never a good place for it to be. The importance is that it is likely to maintain the trough and unsettled conditions across the UK and there is little signs of this pattern, which has been evident for numerous weeks, changing. This can also be seen within the latest ECMWF and GFS ensemble mean charts;

Both charts have a marked trough of low pressure across the UK, with pressure generally higher to the North-west of the UK and also across more Eastern Europe where it has been for weeks. Note as well, the usual summer-related main Azores high pressure continues to be held well to the south-west of the UK, with little or no sign of this influencing the weather across the UK as July progresses. The persistence of the predominantly cyclonic conditions is also represented well within the latest GFS ENS atmospheric pressure graph, randomly selected for Central areas of the UK (Northern England);

That really is quite a shocking prediction at the moment with also relatively good, if not very good ensemble model agreement that up to the 18th or 19th of the month at least, the atmosphere pressure is unlikely to get above 1020mb, which for the time of year, is again, shocking. You can also clearly see that directly associated with this signal for relatively low pressure is the consistent signal for precipitation across the bottom of the graph as well throughout the forecast period, which continues to support the likelihood of further precipitation, some of which could be significant at times as well, not just across Northern and Western areas of the UK, but also across Southern regions too.

So in summary, I have quite high confidence to suggest that the first half of July will continue (unfortunately) in the same pattern that we have had to endure throughout June. Low pressure is set to dominate and as a result further relatively cool conditions are forecast with perhaps some additional large rainfall totals at times depending on the specific events and details as the next few weeks progresses.

So, what about the second half of July?…Any potential changes?…

Unfortunately, at the moment I don’t envisage any significant changes;

Given the time frames involved then clearly confidence levels do drop away, but what I do expect is further unsettled and cyclonic conditions to continue after mid-month as well, at least for a time. I have highlighted this as an issue in some of my previous blogs and that is particularly during the summer, long-term pressure trends become insignificant and weak given the nature of the weather during the summer and at the moment that is the case for say the final 7 to 10 days of July. As a result the far end of July may well begin to see a pattern change. It is often a time for the broader synoptic pattern to change if it has been ‘stuck in a rut’ for a long time, so as a disclaimer please acknowledge the above image with some open thought and also hope that the final week or so of July may begin to see a change to something warmer and more settled.

So in summary and it doesn’t bring me any joy to highlight this, but the first half of Summer 2012 looks to be a complete washout with the first half of July now expected to be unsettled and predominantly cool. The second half of July may well maintain these unsettled conditions, particularly for at time after mid-month, before perhaps changing at the end of the month. Clearly however, overall July may also now turn out to be quite poor as well, particularly if 2 or 3 of the 4 weeks of the month do end up being predominantly unsettled.

As ever, all thoughts and comments are welcomed and as usual I’ll review the first half of July mid-month and also take a closer look at the second half of the month and into early August…Here’s hoping by then there is something on the horizon in terms of summer-like weather, as clearly these weeks and months are ticking by.

We can only hope that something out of the ordinary happens and breaks this stubborn pattern.

[Alex]

I think it's quite apparent that the strong trough near to us, is the atmosphere still acting in a la Nina base state which means low angular momentum and MJO phases 1/2, I don't know why this is happening because we have a neutral ENSO state. Until angular momentum swings out of almost record low figures, I can't see much change. Heading into MJO phase 3 may push the trough slightly north but that won't help the majority apart from Maybe Essex and Kent.

http://www.esrl.noaa.gov/psd/map/images/reanalysis/aam_total/gltotaam.sig.90day.gif

Edited July 3, 2012 by Alex

[A Winter's Tale]

Good evening all.

Well not much has changed in the last month as high pressure continues to persist over that ever so familiar place that's Greenland. A record breaking wet and also the second dullest June on record was how summer 2012 started with some severe conditions at times. Even as a person who likes all aspects of our weather in general, I have to say that I would rather our weather become a little more varied and seasonal but we have to deal with what we've got in the meantime and that is to focus on what the weather is doing and pin-point possible severe conditions or even short-lived periods of more pleasant conditions in some areas. It's also key to follow the general trend into the rest of the first half of July to see whether the Greenland high is likely to persist further bring generally below average temperatures and above average rainfall.

Overnight, the area of rain centred over the south of England will move further north and east with some patchy light rain/drizzle over in the SW, Wales, parts of the Midlands. Another area of rain in the west be situated over Northern Ireland before pushing pushing further east into parts of Wales, SW Scotland and N England. In general tonight should be a rather mild one with temperatures of 13-16C likely. The chart below highlights the main areas of rain - quite widespread and heavy although the north of Scotland should be dry and clear overnight into the morning.

The rest of the morning will be a mostly cloudy one with light rain around and temperatures around the mid-high teens. Skies may begin to clear in NW Scotland, Ireland and E England as we head into the afternoon. Elsewhere, it's still a mostly cloudy and damp picture with more persistent rain in parts of S and C Scotland along the south coast and northwards into parts of Wales and NW England. Temperatures should max out at 17-20C. Skies may even begin to clear in parts of Wales, the SW and Northern Ireland. The chart below does show some nice looking temperatures but unless you've got clear skies, the damp and dull conditions won't be inspiring.

Into the evening, skies will clear further in N Scotland, the East and SW with only Central and North Eastern areas keeping the cloud cover. Rain will continue to persist around the S Coast and heavy showers are possible anywhere between Glasgow and Birmingham. As we head into tomorrow night these showers should become less widespread in what should be another mild night.

Thursday, low pressure continues to influence our weather and some heavy and persistent rain is likely in S Scotland all the way down to East Anglia with some precip around the SW and Ireland. Sunshine is also likely around much of Northern Ireland and with temperatures up to 17C it should feel pleasant but you can't rule out cloud cover around the coast. Some "prolonged sunshine" could also be possible anywhere from London in the east to Cardiff in the west and northwards up to Manchester but cloud cover should increase in Wales and in Manchester rain is a possibility. The east coast should have a dull and quite damp day although the far NE of England may escape the rainfall for periods. In Scotland, parts of Aberdeenshire, Highland and the Western Isles should remain dry but cloudy but further west and south there should be rain and even SE Scotland could have a damp day. Temperatures should be at 16C-22C. 20C is possible along the east of England and NE Scotland. In the chart above, you can see an easterly wind affecting the UK with 10C uppers along the east coast and NW Scotland. This should be responsible for some "warmth" in the east and the fohn effect bringing 20C temperatures to the NW Highlands.

Through Thursday night rain should be confined to the far NW, parts of Ireland, the S coast and and parts of the east coast. It should be quite a mild night with clear skies in most areas of Wales and southern and central parts of England away from the coasts.

The chart above again shows the rain being mostly confined to the North and the coastal regions of the West and north east. Quite heavy rain is forecast around SW Scotland and Northern Ireland.

The synoptic situation for Friday is similar to Thursday with an easterly wind (quite strong in the north), low pressure centred right over the UK and high pressure continuing persist to our NW. However, Friday looks like being a much wetter day than Thursday with widespread precipitation anywhere south of C Scotland with only a few breaks over land and far coastal and eastern regions escaping the rain. In Ireland, it should be mostly damp and cloudy with occasional dry spells whereas in the N Scotland a drier day is likely here although moisture can't be ruled out with the widespread cloud cover. There doesn't look being much sunshine on Friday although coastal regions of the far SE might be lucky. With the recent floods and landslides, the weather conditions over S/C Scotland and N England and even the SW won't be good news. Some very heavy rain is likely in these areas (especially the north) so the Southern Uplands, the Cheviots (even Lake District) and possibly the Welsh mountains could be experience heavy rain and flooding in the valleys. Temperature wise, it should be 15-21C, coolest in the NE and warmest around East Anglia.

The chart below illustrates the very wet conditions that the North of England and South of Scotland are set to experience. The met office have issued a YELLOW WARNING for this - http://www.metoffice.gov.uk/weather/uk/uk_forecast_warnings.html

Overnight the rain should move north and west so North Scotland and Northern Ireland is likely to experience some heavy prolonged rain. Some moisture is possible in some coastal and hilly regions but nothing like as widespread or heavy as Friday.

On Saturday, as shown in the chart above, the wind direction for most changes to more of a North Easterly (especially in Scotland and Ireland). Low pressure continues to stay over the UK and at the moment Saturday looks like being a dull and damp day. Not everywhere will see rain with east coasts likely to see some localized dampness but more persistent rain is likely to be centred over London, Central areas, SW and Wales. North England should also have a dull day with the possibility of same rainfall but the focal point of the weather will be further north as the front moves northwards. Scotland should have a wet day with the NW, Western Isles and Northern Isles the last to escape the rain. The heaviest of the rain will be further north than on Friday with the northern half and North east in particular having very wet conditions. This could lead to more flooding issues. In Ireland, it should be cloudy with the most of the rain likely in the north. Temperatures will be disapointing in Scotland at 14C but further south 17-21C is expected.

Overnight, the heavy and peristent rain continues in northern scotland which is a concern. Some more rain is likely in the SW and precip is possible in coastal regions. It should be a relatively cool night.

So the next five days look set to be unsettled with everywhere seeing some rain with the heaviest it likely on Friday and Saturday. Some showers and patchy rain is likely almost anywhere as it looks like being dull but localised brightness and some more widespread sunshine is expected on Wednesday in areas. Temperatures should be quite mild at 15-20C with the warmest of conditions in the south and east although the fohn affect may bring some warm temperatures at some stage in NW Scotland. Winds may also be noticeable, especially the further north. The key events of the week looks like the heavy rain that's set to affect the north later this week and it's worth keeping an eye on this as we've already seen floods and landslides this summer. So certainly into the first 7-8 days of July it looks like more of the same as we follow on from a record breaking wet June. At no stage you can rule out summer as you always get rain in any season of the year but the quantity and regularity of rain recently has been noticeable. But at the very least some warm and sunny days are likely so some days of pleasant summer weather is possible - in that respect you can't rule out summer - but whether it will be short-lived and mixed in very wet and dull conditions is something that we needs to be seen. With the models showing high pressure over Greenland up till around mid-month it does look like the first half of July will follow where June left-off but short-range varieties in our weather will determin the quality and type of weather we get. High pressure over Greenland is a synoptic that doesn't allow for much flexibility in our weather.

At the moment, I'll say that we'll be in the same set-up until around the end of the month and I feel that August could see a change but until then, as a weather enthusiast I'm going to follow the models to see whether a change might occur earlier, follow the weather conditions being experienced across the country and try to make the most of any pleasant spells.

[ribster]

no rain here again today, im no expert but i knew it wouldn't be as bad as people feared, i see many posts from people saying it will be unsettled with plenty of rain and showers the models never looked that wet to me, yet again people go over the top when they see synoptic s with a bit of low pressure over us

Slighty imby I think, as there has been plenty enough rain here, all night long and again on and off during the day, as for watering the vegetables, haven't had to do that for the last couple of days. Of course there will be variation from place to place, especially regarding rainfall, but like it or not the general theme is unsettled.

[Robbie Garrett]

I think my original thoughts regarding July where correct. This unfortunately sums it up....

Edited July 3, 2012 by Robbie Garrett

[Thundery wintry showers]

I had a few inward gulps seeing the GFS 18Z run in particular- the low pressure area for Friday and the weekend is being revised further south with each run, bringing the dull cold wet conditions (associated with a trailing front on the northern flank) further south and restricting the warmer, brighter, thundery type conditions to a smaller area of the country. As the Aberdeen ensembles indicate, that front could produce some serious rainfall and renew the threat of flooding in places, even more so than any thundery outbreaks tomorrow.

GFS 18Z has the rain belt now over northern England on Friday, though it does retreat back northwards again over the weekend, with temps of 22C indicated for central southern England for Sunday with a mix of sun and showers for the vast majority.

Next week, on both the GFS and ECMWF, is increasingly screaming deja vu as I'm pretty sure I saw near-identical charts to those sometime around the 12th June. A similar washout is not guaranteed as the ECMWF FI, and the ensemble mean, show a weaker and more northerly tracking jet which might promote slacker brighter showery type conditions, but on the other hand the GFS FI is repeatedly keeping things as per June.

[Thundery wintry showers]

Friday is now looking like a stark example of last minute changes resulting in what was originally a fairly bright, showery and thundery outlook being scuppered by changes resulting in a front being stuck across most of the country at short range- the day is now looking like a washout for a large band extending from the Midlands to southern Scotland, with heavy and persistent rain potentially leading to flooding. It turns temprarily drier though still mainly cloudy across northern Scotland while the bright showery weather holds on over southern England. The rain then retreats into Scotland on Saturday, while remaining potent, and allowing a brighter showery weekend elsewhere.

Tomorrow is looking like it could be fairly warm in the south with highs of 22-23C, but today once again has rather more cloud than the GFS originally indicated and this will suppress both temperatures and the thundery potential that has so far been indicated for northern England. The satellite images show generally less cloudy skies behind today's cold front though, so it may be that for once the projection of brighter weather for tomorrow verifies. For the longer-term I have little to add to last night's assessment except for the fact that this morning's ECMWF has shifted towards joining the GFS in showing a near-direct repeat of what happened around 10-15 June.

[Summer Sun]

Another unsettled run from GFS this morning with another deep low in FI

http://www.netweather.tv/index.cgi?action=nwdc;sess=

UKMO is also unsettled

http://www.netweather.tv/index.cgi?action=meto;sess=

And ECM completes the pack

http://www.netweather.tv/index.cgi?action=ecm;sess=

[shedhead]

Friday is now looking like a stark example of last minute changes resulting in what was originally a fairly bright, showery and thundery outlook being scuppered by changes resulting in a front being stuck across most of the country at short range- the day is now looking like a washout for a large band extending from the Midlands to southern Scotland, with heavy and persistent rain potentially leading to flooding. It turns temprarily drier though still mainly cloudy across northern Scotland while the bright showery weather holds on over southern England. The rain then retreats into Scotland on Saturday, while remaining potent, and allowing a brighter showery weekend elsewhere.

Tomorrow is looking like it could be fairly warm in the south with highs of 22-23C, but today once again has rather more cloud than the GFS originally indicated and this will suppress both temperatures and the thundery potential that has so far been indicated for northern England. The satellite images show generally less cloudy skies behind today's cold front though, so it may be that for once the projection of brighter weather for tomorrow verifies. For the longer-term I have little to add to last night's assessment except for the fact that this morning's ECMWF has shifted towards joining the GFS in showing a near-direct repeat of what happened around 10-15 June.

This post is a good example of how you can end up chasing yer tail by trying to be too precise in this type of situation. What you said earlier this week has undoubtedly proven to be correct in so much as some places have seen little in the way of rain and even a little warm sunshine, but given the fact LP remains over or close to the UK for several more days the emphasis has to remain on showers or longer spells of rain imo, some of which will be heavy and thundery.

Edited July 4, 2012 by shedhead

[Bobby]

Blimey, the NAE has some torrential rain moving into SE Thursday night and spreading across many central/S. Areas and probably eventually Wales/SW England.

The NMM is similar but further North

The GEM has a possible major flood event for SW Britain as an area of heavy rain becomes stalled, 24+ hours of heavy rain

Edited July 4, 2012 by Barb-

[tinybill]

i posted this on the British GP thread this is for Sunday looks a bit wet!!

[Bobby]

The NAEFS still shows the unsettled weather to continue for the forseeable with low pressure in control all the way to the end of the run

[shedhead]

The NAEFS still shows the unsettled weather to continue for the forseeable with low pressure in control all the way to the end of the run

This is indeed a thoroughly depressing chart to see for the final third of this month, because IF it verifies it will effectively writes July off too. Worst still troughing looks to have become even more extensive, taking in much of Scandi and northern parts of the continent, but no prizes for guessing where the deepest troughing of all can be found!!

[Carl46Wrexham]

What odds on Summer 2012 being the worst ever? I wouldn't bet against it at the moment...June being diabolically poor, and July continuing in the same vein with absolutely no sign in any of the models of a change. Meh!

Edited July 4, 2012 by No thunder here!

[Bobby]

The GFS ensembles do all sorts of things with that front late Thursday/Friday so a lot of uncertainty on the position. Quite a few are like the op and quite a few are more like the NAE/NMM with it further south, ie:

So going to be a bit of trouble to forecast I think because theres flooding potential where it hits. Lets hope the Met Office are on the ball.

Edited July 4, 2012 by Barb-

[shedhead]

What odds on Summer 2012 being the worst ever? I wouldn't bet against it at the moment...June being diabolically poor, and July continuing in the same vein with absolutely no sign in any of the models of a change. Meh!

I'd say it's odds on already, perhaps 4/5 and will be as low as 2/5 come next week unless we can see some potential changes for August by that time. I realise GP never promised us a Summer of 76 this time, but even he must be surprised just how badly this one is panning out; I most certainly am.

[Interitus]

Blimey, the NAE has some torrential rain moving into SE Thursday night and spreading across many central/S. Areas and probably eventually Wales/SW England.

From the enlarged zoomed image, the Friday 03z chart is giving 3 hour rain totals in excess of 4inches/100mm as it leaves northern France!

edit: interesting that the Met Office warnings emphasis is slightly further north than area the you mention highlighted in the NAE

The warning is closer to the current GFS which pushes the rain further east into Belgium and Holland before it arcs westwards across the North Sea into northern England.

Edited July 4, 2012 by Interitus

[mushymanrob]

I'd say it's odds on already, perhaps 4/5 and will be as low as 2/5 come next week unless we can see some potential changes for August by that time. I realise GP never promised us a Summer of 76 this time, but even he must be surprised just how badly this one is panning out; I most certainly am.

me too, its remarkably poor and theres no sign at all of a change of pattern.

bum.

[phil nw.]

Looking in the short term after a showers type day tomorrow with some sunny intervals here and there Friday and into the weekend look very wet for many.

Low pressure developing with it`s slow moving fronts across the UK by Friday.

NAE and GFS have placed the approach of the heavy rain band slightly differntly for 12z Friday but it looks like many central and northern areas will get a soaking at some point.

More heavy showers or longer spells of rain are likely over the weekend after the main rain band moves away north so i would imagine the next 3-4 days will see those rainfall totals keep well ahead of the average for this "Summer" so far.

The low will take into early next week before it finally drifts off into the North Sea when we may get some chance to dry out.

Apart from the far south east though temperatures remained very depressed.

[Jonathan Lang]

At least this evening's precipitation ensemble is looking a bit better after the weekend washout

[Jason T]

Bit of wishful thinking here, I was just wondering if there has been an instance where a pattern has changed in a stubborn pattern scenario and output has not picked up on it,Guessing it must be possible,In cases of hurricane activity or volcanic activity or something else.Would be interesting to know even better with detail.????

JT

Edited July 4, 2012 by Jason T

[phil nw.]

At least this evening's precipitation ensemble is looking a bit better after the weekend washout

Hello Jonathan and welcome to the forum.

Yes at the moment next week looks drier at least as weak ridging extends from the Azores High.

so something a bit better for a few days perhaps.

Edited July 4, 2012 by phil n.warks.