Thinking about how August may begin, today's model output produced two main solutions for the evolution from Friday onward. In both scenarios, the Azores High to retreat well west of the UK. Obviously this means conditions are more likely than not to be changeable for the first week of August.
Then, however, some models go for major height rises to our NE and/or NW, trapping continental troughing over England or just SW of the UK, while the remaining models have less pronounced height rises and bring in the Atlantic from the NW.
Both evolutions hint at a recovery after the first week of August, but it's a shame to be seeing unsettled charts again so soon. Come Thursday evening I'm sure that I won't be all that bothered by a poor outlook; I've simply become used to it now - that's why I've not been complaining much so far this summer! Yet even after so many poor summers I would struggle to maintain a sane mind if I was put through what some parts of the north have been through, and I strongly hope that we get a nice big UK high in August,centered over Northern England.
Since 18th July the CFS output has overall shifted slightly, such that lows from the Atlantic travel SE into the N. Sea or Scandinavia while high pressure is often near to the west. This basically means that the amount of ridging into the UK has been reduced, with troughing having more of an influence. There are a few fleeting warmer spells, but generally the picture painted is one of a cool month with showery spells and scattered dry days, these most frequent in the west. Not long after mid-month, the infamous Greenland High begins to really show its hand from time to time... but there is large variation from run to run regarding it's frequency, extent and positioning.
I've found it very interesting watching the CFS runs ebb and flow in response to changing signals; they don't lurch about much, unlike the shorter range models. I guess that for whatever reason, CFS doesn't tend to make mountains out of molehills!
Recent CFS runs have shown our best chances for more settled weather in August to be as follows:
This is not entirely on topic, reaching far beyond summer 2012, but rather than creating a new thread I've decided to sneak it in here and hope for the best
We're in an incredible run of poor (for the most part especially for the north) summers really, and it will be quite something when it comes to an end and we see warmer and sunnier than average summer months return.
Or at least, I hope it will. A part of me is concerned that the melting Arctic is creating a pattern that won't change unless the ice recovers dramatically... or perhaps it's possible that if all the ice melted, the jet would tend to meander so far south that all the troughing goes to the Med. and Africa? After all, the temperature gradient would reduce considerably further. We could see a very broken jet stream pattern - such as we saw recently and continue to see in a less dramatic form - occuring with high frequency, making the weather more unpredictable and potentially allowing some extraordinarily meridonial setups (i.e. where the jet loops to the greatest level, allowing lows to travel long distances in all sorts of directions, including SW, W and NW).
Perhaps this is a good title for a discussion: how will the atmosphere respond if and when the Arctic melts entirely?
Reality Check: at least in terms of temperature, the recent summers have not been far from the long term averages (2007 and 2011 below, 2008 near average, 2009 and 2010 actually above, this year not yet firmly nailed one way or the other). Only when compared to the 1994 to 2006 period could they be termed notably cool.
Even in terms of rainfall and sunshine, I suspect (without know the numbers by heart) that only 2007, 2008 and this year will have been notably dull and wet. I suspect that 2009, 2010 and 2011 may well have had near average amounts of rainfall and sunshine, though I am ready to be corrected.
So, it's not as "incredibly poor" in your terms as you say, but I suspect that many on here do not or cannot remember summers before 1994 and this is where the depression of the last number of years is, at least in part, coming from.
One more thing on temperature (which is the statistic I know more about): It is true that there has been a dearth of warm (>1c above average) summer months since 2006, but there has also still been no return to the notably cool summer months that happened frequently in the past. So, whilst it's 6 years and counting since the last >1c above 61-90 summer month, it's now 19 years and counting since the last >1c below 61-90 summer month
Edited by user 31 July 2012 21:51:31(UTC)
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I would agree. I can remember summers from around 1971 and from then until 1993 there was some real shxte. What is different this year is the amount of rain, especially when you factor in April. That has been notable.
I effectively called summer over yesterday in terms of settled and warm
Temps 1.25°C below the average, 168% of the normal rainfall and 81% of the normal sunshine.
June and July have certainly been poor in combination this year.
In 2010 and 2011 it was actually drier than average IMBY and sunshine wasn't too bad either. The lack of lengthy fine spells aside from June 2010 has been a bit testing though.
I must admit that my impression of an incredible run of poor summers was formed mostly as a result of reading so many negative reports and comments from posters in the north over the past few summers, and I gather that it has indeed been mostly dire up there. England hasn't faired nearly as badly, as far as I know.
So... any views on the potential impact of the Arctic melting completely one year? I'm very interested in people's opinions on this one
Here's Terry Scholey's August Forecast:
August 2012 – final update.
Firstly, thank you for the positive feedback received regarding the success of the July forecast.
It’s been a while now since we have had a decent August and with only one very warm day during the first half of July often a good indicator of the weather to come during August, the prospects hardly look inspiring. So yet another changeable month seems likely, although there are some signs that conditions will improve later that should be confirmed in the next mid-month to mid-month update.
At present and after a very unsettled start, the most promising periods this August appear to be briefly during the second week and into the final ten days, but finer intervals in the first half may tend to be ‘fair’ rather than fine. It may be unsettled and cooler again around mid-August, with mostly the east and south although not entirely settled, probably seeing ‘tastes’ of late summer into the final week.
The mean average temperature should be somewhat above average in the south and south-east and slightly below in the north and west. It could be wetter than normal especially in the north and west until around the 18th with drier conditions thereafter, although local storms will cause variations.
Weather period breakdowns:
August 1st to 7th: Low pressure dominates giving generally unsettled conditions, with only brief drier, somewhat warmer intervals. There will be showers, some heavy and occasionally prolonged with hail. Thunderstorms will give local torrential downpours perhaps ‘flash’ flooding, gusty winds and maybe even funnel clouds. Temperatures will generally be close to or somewhat below normal reaching between 17 and 23C, with minimum values mostly in the range 9 to 14C.
August 8th to 12th: Improving and drier generally, after some showers at first, these mainly over Scotland and in the north-east. There will be lengthening sunny spells making it fine later, although cloud amounts will vary for a while. Temperatures should rise slowly through the period, eventually reaching say 18 to 20C in the north and a warm or very warm, 22 to 25C in the south. Minimum temperatures should mostly be between 8 and 15C, perhaps with some chilly nights at first.
August 13th to 17th: Probably fine and warm or very warm and perhaps slightly humid to begin with, but turning increasingly unsettled again. Showers are expected probably from the west that could be heavy in places again, with thunder briefly. By mid-month it could have turned rather cool and mostly cloudy with further rain at times. By the end of the period, daytime temperatures could be getting no higher than 14 to 18C but the nights should remain relatively mild, with minimum values say 9 to 14C.
August 18th to 22nd: Gradually improving and becoming drier as pressure builds, either from the south-west or north-west. Later a ridge perhaps to the north or a slack pressure regime should give much warmer conditions, with lengthening spells of sunshine. Temperatures should rise slowly through the period to between 19 and 25C by day, with minimum values 11 to 16C by night.
August 23rd to 28th: This period could be warm or very warm and rather humid, although with some uncertainty as to whether winds will be between east and south or from the south or south-west. The former would bring very warm even hot, hazy days but with showers and some thunderstorms breaking out occasionally. The latter would also bring warm, humid conditions, with Scotland, Ireland and the west cloudy, breezier and unsettled at times. The best of the weather would be in the east and south, but with the risk of a few showers locally heavy giving thunder particularly later. Top temperatures would be say 19 to 27C, with humid nights when the thermometer may not fall below 11 to 17C.
August 29th to 31st: Showers mostly in central and southern areas still heavy with thunder in places, should fade as probably mainly dry weather elsewhere spreads to most parts. By the end of August, high pressure could be the dominant feature giving fine but fresher still warm conditions with sunny spells in generally light winds. Maximum temperatures should be 18 to 23C, with chillier nights although not unduly so as the thermometer probably falls to between about 8 and 13C.
31 July 2012 T.G.S
Re the run of poor summers the current run [excluding 2012 which has been dire so far] is quite exceptional. Looking at Kev Brads' summer index for the Manchester area the five consecutive summers 2007-2011 is the worst five year run in his record dating back to 1901. Also, Manchester is a reasonably central location for the UK - extremeties such as Kent or the Western Isles often differ in summer from the rest. Parts of NW Scotland are presently experiencing a spell of below average rainfall.
The main cause of the poor run is subject of disagreement. No doubt there are multiple causes, but IMO the evidence that reduced arctic sea ice is the main culprit is weak. Changes in the sun's output [not TSI] are probably playing a more important role. Both of these influences [reduced sea ice and solar changes] have been discussed in the climate forum recently.
Well, another pretty decent summer's day here. Warm sunshine til eleven and from 4, with light showers from muggy cloud inbetween. The point is to illustrate that in the "unsettled" regime things are actually fairly decent down here. The warm week appears to have re-set the weather and the new pattern whilst not as good as the settled week that preceded the olympics, is pretty decent in comparison to the cool windy wet dire stuff that preceeded it for most of April May June July. Prospects for the summer - hopefully more of the same, with a bit more high pressure thrown in. Final thought on this post - the weather started to improve around 19 July - and if the improvement is sustained then meterologically that woukd make it a summer of 2 halves - the first unrelentingly poor, the second warmish, sunnyish and dryish.
Genuinely sorry to hear its been so bad for so long. But you know the old adage "mother nature pays its debt be it dry or wet", well, IIRC you enjoyed mild In February while some froze in February and enjoyed an amazing March with 23c and more!
I blame man for melting the arctic ice (not wanting to be controversial. Its my genuine belief and Im not alone in holding that view)
Wishful thinking is always dangerous and often one ends up with scrambled egg on ones face...however, I remain defiantly optimistic that sooner or later before the equinox that high pressure will return and all - or as damn near well as - will benefit. Maybe from early August for some! Average for most Good for some - as always its location specific.
Get out the prayer mat.
Think the point is being missed here - As has already been widely documented, it is the high night time minimas that are skewing the averages.
"Incredibly poor" is not an unrealistic term to use. Just ask those in areas that have repeatedly been flooded, markedly lower than average sunshine, depressed day time temps, and a relentless conveyor belt of LPs slamming into the British Isles over the last 4 months.
Yes, some will not have been affected as badly as others, but for those not in the "I'm alright Jack" camp, it has been incredibly poor.
First 2 weeks of August looking unsettled at best (no where near as bad as we've seen). For those hoping for HP to establish itself over the coming weeks to redress the balance may be bitterly disappointed.
All eyes to Autumn...
Edited by user 02 August 2012 13:08:13(UTC)
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Hopefully 'Glacier Point' and 'Alex' on Netweather won't mind if I quote them here;
GP: "This topsy turvy period continues.. Longer range model tools generally failed to pick out the developing ridge over Europe over the next week. GEFS keen to drop another trough over the top of the UK and Scandinavia during week two althoug I suspect the trough will end up further west. What chance another plume to end the summer ?"
Alex in reply: "The teleconnections don't really match a plume either unless I'm mistaken, GWA phase 1-2, MJO phase 8-1 and decrease in angular momentum? However a trough over scandi has been progged and is more in line to develop towards the end of the month however I would think another plume isn't out of the question before we get there."
GP's response: "I would go GWO in low phase 2-3-4 orbit, MJO phase 2/3 for that time, perhaps angular momentum increasing a touch. The key thing for me is the SOI tanking -ve over the last week, allied to a weakish but not persistent enough easterly zonal wind anomaly at high latitudes. Think troughing signal in the Atlantic and weakish sub-tropical ridge over the Azores / stronger manifestation of the Euro ridge."
Make of that what you will...