August CET

[Optimus Prime]

The lowest temperature last night was the Cairngorm at +0.9c. Great dun fell dropped to +4.2c, SHap dropped to 5.9c and Benson 6.8c. All well below the August nightime average.

Been slightly cool here as well lately, sufficient enough to have my average minima 0.6c below average (outside the CET zone) While the Metoffice has it 0.6c above normal.

According to Philips Edens site so far this month, perhaps surprisingly it's cooler then last year. Following on from that very warm July I remember the heat still having effects into the first half of August.

[Thundery wintry showers]

Although an above average August is very much odds-on, I think there is more scope for a below average August than last year due to wetter ground and less residual warmth around northern Europe. July 2007's synoptics, though certainly anomalously cold, probably weren't any more so than those of August 2006 yet the CET was a full degree lower.

[Stu_London]

Although an above average August is very much odds-on, I think there is more scope for a below average August than last year due to wetter ground and less residual warmth around northern Europe. July 2007's synoptics, though certainly anomalously cold, probably weren't any more so than those of August 2006 yet the CET was a full degree lower.

What makes you think that? - we will be below the running average by Wednesday and the ensemble mean is below average for the forseeable - granted things may changes but "very much odds on" is a big call

[Lettucing Gutted]

as far as I'm concerned anything which might help a real autumn to materialise would be a boon. It's my favourite season, and the one that has most vanished in recent years.

Yeah. That's a very key point WIB High. A real autumn would really assist in the developing weather patterns for a cold winter in Britain. Since on average the Northern Hemisphere's Oceans reach their highest temperatures of the year in September the rest of Autumn is the season when the SSTs begin to cool very slowly so the lower the SSTs are this September the better the chances they will be low enough for a cold winter. This is especially important since Britain is a maritime climate.

The high SSTs cooked up by last September really killed off last winter.

[summer blizzard]

Outputs and ensembles suggest near average weather likely until around the 19th, when there are signs of a potent northerly plunge.

[kold weather]

It may help Craig but you could have the coldest Autumn ever but if you get a winter dominated by a bartlett high those cooler SSt's are not going to make a slight bit of difference!

Anyway temps overall look about average upto the 15th, though milder mins between the 12-15th may hlep to just push the CEt above average IMO. After that and hints that another cool down will occur wit hthe Azores high beefing up but in the wrong place, if that happens an dthe Azores high gets that strong temps could take a quick nose-dive.

[Lettucing Gutted]

It may help Craig but you could have the coldest Autumn ever but if you get a winter dominated by a Bartlett high those cooler SSt's are not going to make a slight bit of difference!

Yeah the Bartlet high is another ting we need to watch out for. It was almost always present last year between last September and March 2007 give or take a few days.

Do the current British SSTs, MEI index, AO, Stratosphere temperatures, QBO, NAO and PDO etc still favour a sub 15.8C August or "normal service resumed" hot and humid?

[Stu_London]

From www.climate-uk.com

16.7C - Bang on average as predicted. This morning looks quite nippy again in the CET zone (milder to the south) so I would expect another 0.2 or 0.3C to be knocked off today.

The nights get slighlty milder thereafter which should slow or stop the fall, however apart from the odd 0.1C up or down here and there, a significant rise does not look on the cards in the next week or so.

[kold weather]

Broad range of temps as the overnight mins, some places got down to 6C but other held at 11-12C in the CET zone so clearly its goin to be down to exactly where the stations are as to how low the mins turn out to be. Maxes today in the 17-19C should cause a drop in the CET even if the mins are on the higher side.

Longer term showing quite bad signs IMO with the northern blocking always forecasted to breakdown in deep FI but it keeps getting pushed back. If it doesn't break down soon then we could have another round of flooding issues as the jet is starting to show signs of re-gaining energy as the thermal gradient is starting to grow again over the poles. This strengthening of the jet may well provide another set-up close to what we've seen thorughout June-July as the strong northern blocking wil lkeep the jet surpressed somewhat. The GFS does eventually rid us of the northern blocking by the 20th but I have my doubts given the last strong phase lasted 30-45 days and I can't see no real reason for this one not to last as long and if thats the case then clearly this August is going to have a hard time staying above average in term sof the CET tohugh thats not to rule out the odd warm plume here and there, esp if we do get help from the tropics later in the month.

It should be noted that 1993 had a very similar phas eof northern blcoking which just came back over and over again, while its way to early to say its going to be like that the northern blocking so far has acted a bit like that year.

[Weather-history]

21st June-7th August

CET: 15.2 (-0.9)

[Thundery wintry showers]

What makes you think that? - we will be below the running average by Wednesday and the ensemble mean is below average for the forseeable - granted things may changes but "very much odds on" is a big call

I said that in view of the underlying warming trend, but then again, it's far from guaranteed. This August is starting to remind me a bit of a warmer version of August 1993- dry relative to the unsettled July but still on the cool side.

[Stu_London]

I said that in view of the underlying warming trend, but then again, it's far from guaranteed. This August is starting to remind me a bit of a warmer version of August 1993- dry relative to the unsettled July but still on the cool side.

I agree the overall form horse is mild - however very recent form is perhaps different - maybe the going has changed!

[AtlanticFlamethrower]

My +1.3C guess s broken.

* I expected continued warming SSTAs, whereas almost since the first day of August we've had cooling SSTs.

* I expected a pattern change from 95% martime to at least 50/50 continental/martime air flow. GFS suggesting 90% westerlies/north-westerlies and wet weather - much as before.

CET looks to be heading toward neutral-negative values for the second consecutive month.

[SteveB]

My +1.3C guess s broken.

* I expected continued warming SSTAs, whereas almost since the first day of August we've had cooling SSTs.

* I expected a pattern change from 95% martime to at least 50/50 continental/martime air flow. GFS suggesting 90% westerlies/north-westerlies and wet weather - much as before.

CET looks to be heading toward neutral-negative values for the second consecutive month.

I wonder when was the lasT time we had two consecutive below average CET months.

[Stu_London]

I wonder when was the lasT time we had two consecutive below average CET months.

It may have been as recent as Feb/March 2006 - Feb was close - March was comfortably below average

[kold weather]

Feb-March 2006 was the last time, indeed we came pretty close to having 5 months below average in a row with only Jan ending up a touch above average, November, December, February and March all coming in below average.

Stil its to oearly to make a call as to what August will come in around, its a bit like June with an unsettled and slack set-up but no real drag of cooler air from the north which does hint at a month close to average however still too early to make that sort of call, mins do look a little milder mind you next week which may help to prevent any further drops once the drop of the next few days is done.

[Optimus Prime]

I wonder when was the lasT time we had two consecutive below average CET months.

We had two in 2005. November (-0.7c) and December (-0.8c) January 2006 was 0.1c below average and then we had 2 cool months in a row February (-0.5c) and March (-1.4c)

In the 90s the longest run of below average temperatures was in 1993. July (-1.3c) August (-1.5c) September (-1.3c) October (-1.9c) and November (-2.4c) an exceptional run of cold months.

[Snowyowl9]

Last night was chilly 6.9c and I make it the coldest august night for 12 years.

http://www.wetterzentrale.de/archive/ra/19...00119950809.gif

If only we could have a high like that now.

[damianslaw]

We had two in 2005. November (-0.7c) and December (-0.8c) January 2006 was 0.1c below average and then we had 2 cool months in a row February (-0.5c) and March (-1.4c)

In the 90s the longest run of below average temperatures was in 1993. July (-1.3c) August (-1.5c) September (-1.3c) October (-1.9c) and November (-2.4c) an exceptional run of cold months.

Oh to have another autumn like 1993 we can only hope, I cerrtainly don't want an Autumn like last year, however I have faith this year that we will not see a repeat of last year, helped in large part to the cool summer and lower SST's.

In reply to the low minima, yes this is perhaps the most noteworthy statistic of the month so far, to get 2 days of cool minima so early in the month and slap bang in the middle of 'high summer' when we have often recorded both our highest maxes and minimas is very noteworthy indeed, long may they continue the heat of the weekend reminded me as to why I don't like heat i.e. could not sleep...

[summer blizzard]

http://www.wetterzentrale.de/pics/MT8_London_ens.png

Growing ensemble support for a potent northerly plunge from the 19th onward, we could see some very low minima recorded and i would'nt ule out 0.5C-1C being knocked off the CET during this northerly period.

Still a chance of a plume from the 23rd so i wont make rash assumtions, however the odds on a second below average month are shortening fast imo.

Infact, until the 21st, there are only 3 of the 12 days which look to see a rise in the CET, the rest look average or below, by the 20th, i expect the CET to be 15.5C-17C.

[Stu_London]

from www.climate-uk.com

Another plunge yesterday

CET to 8th August - 16.3C - (-0.3C)

Entirely down to what is a remarkable early August average minima (7C). The fall would have been greater but for a decent maxima coming to the rescue.

Not as cool this morning but widely single figures in the zone nonetheless and another cool night perhaps tonight should see the CET down to 16C by the end of the working week before stabalising.

A mid atlantic block of sorts appears yet again in the medium term giving a 2-3 day northerly which would probably take us below average and needing another hot spell before month end to avoid a below average month.

At the moment I would say below average is a shade of odds on with a probability of 55-60%

[Weather-history]

I wonder how much minima will have an impact this week. GFS have some lowish minima at times this week.

Certainly has made an impact

Mid June-mid July was below average and now it looks odds on that mid July-mid August will be below average as well

16th July-8th August: 15.6 (-1.1)

[kold weather]

Next week still has above average mins looking at the models however the strong low pressure system and the large amount of rainfall helps to keep the maxes a little surpressed as well. Thickness in the end however don't really look any higher then recently and so the CET will probably end up pretty close to 16C by the 16th and indeed maybe cooler if the GFS northerly type airflow comes off however ther eis some model disagreement about that so we can't really take that as a given.

Range right now is between 15.5-17C as SB said last night IMO.

[MP-R]

I'd say 16.0C. With quite low minima and quite high maxima in different places around the country. Probably an average month.

[eddie]

Looking at the latest GFS I think we will be at 16C or slightly below by the 15th due to some cold nights.

Hard to say what will happen after that but one thing is fairly certain, we won't be breaking any records.

If we are at 16C on the 15th then it would require a second half CET of 22.2C to beat the warmest august (19.2 - 1995) and 9.9C to beat the coldest August (12.9C in 1912)