Highest Temperature in the British Isles/UK this year.

[Nick L]

36.8c, somewhere near London, 2nd week of August

[Jack Wales]

34.5C, early August, Gravesend.

[Sunlover]

33.5 London August 7th

[*AL*]

B) 32.8 24th August in the S/E.

[Joneseye]

33.1C, July 3rd - Wisley

[Paceyboy]

35.1- Evesham Somewhere around late July (23rd perhaps)

Edited May 29, 2008 by Paceyboy

[Roger J Smith]

I'll throw in a guess here, the summer is likely to produce some long stretches of hot weather especially in August, in fact already there is quite a tendency for warm, humid air to build up over Belgium and western Germany and head in the general direction of southeast England, so it would not be surprising if there were a repeat of the August 2003 heat wave at some point around the same part of this summer.

So I will stick my neck out and say there's a chance of hitting an all-time record high (official readings) near 39 C during the first half of August. Let's say 39.1 C just to have an exact number. I suppose somewhere in the greater London area, or possibly Gloucs the best bets for this.

In any case, I think 35 C is the over-under figure given the indications so far.

Just a note, my average error on seasonal extremes in 2008 so far (two predictions) is 0.5 degrees, so this is bound to increase that substantially, or, you'll need A/C, one or the other.

[Jack Wales]

So I will stick my neck out and say there's a chance of hitting an all-time record high (official readings) near 39 C during the first half of August. Let's say 39.1 C just to have an exact number. I suppose somewhere in the greater London area, or possibly Gloucs the best bets for this.

Wow Roger, I thought my punt of 34.5 was pushing it a bit!! What are you thoughts behind that prediction?

[Roger J Smith]

I'm just staking a claim for the extreme value because I think it's in play, your prediction is more reasonable.

The pattern seems conducive to record warmth at some point during the mid-summer period, that's about the whole basis of the forecast. I will be surprised if it doesn't at least make it to your value.

[Jack Wales]

I'm just staking a claim for the extreme value because I think it's in play, your prediction is more reasonable.

The pattern seems conducive to record warmth at some point during the mid-summer period, that's about the whole basis of the forecast. I will be surprised if it doesn't at least make it to your value.

It's just as well re-gassed my aircon last week so I hope your right! Will you be releasing a summer forecast this year?

[Roger J Smith]

Well, I've said this before somewhere on NW, at first I was thinking it might start out rather cool and wet and turn more seasonable (that was perhaps back in April), a bit later on I revised that to near normal and wet first half, hot and mainly dry second half although with severe local storms.

My thinking was revised because the La Nina event seems to be weakening rapidly, sea ice that had surged south around Newfoundland has broken up except along the coast where some bergs are trapped in harbours, and the recent trend towards low pressure in the Biscay area and a SE flow ... it all suggests that controls are weak, heights and thicknesses will be rising, and while at first this could promote a lot of cloud and wet weather, eventually it should break down into a heat wave scenario.

[J07]

It's just as well re-gassed my aircon last week so I hope your right! Will you be releasing a summer forecast this year?

You have Aircon in Tonyrefail?! In your car or your house?

[Nick H]

:lol: 32.8 24th August in the S/E.

That would be the latest date on which the highest temperature of the year was recorded since Cromer registered 32.8C on the 26th of August 1964.

It seems to me that the second half of August rarely produces heatwaves lasting anything more than a couple of days. When was the last time we had a hot spell (i.e. high 20s at least) in the latter half of that month lasting, say, 4 -5 days? We did reach 32C a couple of years ago on the last day of the month but the heat didn't last very long. Even in mid-June you can get a good string of days with high temps. In recent years, it appears that the first half of September has become more reliable than the second half of August for summery weather.

Edited May 30, 2008 by Nick H

[Thundery wintry showers]

The last time it happened was in 1997. The mid 1990s were unusual in that three consecutive Augusts, 1995, 1996 and 1997, all had fairly prolonged heatwaves after midmonth. The 1995 instance was the final hot spell of the summer, persisting in many areas until the 23rd, while 1996 had a southerly plume bringing heat from the 16th to 20th, and 1997 had frequent south-easterly winds and high 20s/low 30s through to the 21st.

Other than that "trio" of Augusts, going back into the 70s, 80s and early 90s, the only other occurrences would appear to have been in 1975, 1976 and 1984.

[Nick H]

Thanks. Just looking at Heathrow's June records, in 2006 it had 6 consecutive days at 26C or higher; in 2005 it had 8 consecutive days at 26C or higher. In 2004, the highest June temp was 31C, in 2005 it was 33C, in 2006 32C - all before the final third of the month. Nothing like that in late August recently.

Edited May 30, 2008 by Nick H

[Roger J Smith]

Seems like late August should be better favoured for heat than in the recent records in the UK. The North Atlantic reaches its warmest values around late August or early September, and the hurricane season is often well underway by late August, something that should reinforce the heights and thicknesses over western Europe.

I wonder if this is some singularity of the modern climate that did not exist in earlier periods. Mind you, we see the same effect here in Vancouver, the hottest weather of the year is quite often late July and early August, and there's a saying around here, when the "PNE" our local major exhibition/fair opens around August 15th, the rainy season usually begins.

September can be quite warm here too, but I doubt that the highest reading of the year happens more than 10% of the time later than mid-August here. It probably happens less often in June than in the UK because we have a traditional cloudy spell in mid-June too, but I wonder if Mr Data has any insight into the past records, regarding late August. It seems to me that there should be more frequent annual maximum temps than what people here are reporting, given the ocean influence.

For that matter, at Toronto where there is no ocean influence, more than 25% of years have their highest temperature in late August or September. In fact the highest temperature since the 1936 heat wave in mid-July was on 25 August in 1948 and the second highest was 2 September 1953. Strange but true on several levels (what happened to AGW you ask? dunno, must have avoided the region for half a century).

[Jack Wales]

You have Aircon in Tonyrefail?! In your car or your house?

In my car!

There is not a great demand for aircon in Tonyrefail but it would have been useful in the house during the summers of 2003 and 2006.

[J07]

In my car!

There is not a great demand for aircon in Tonyrefail but it would have been useful in the house during the summers of 2003 and 2006.

Phew!

British houses do have a tendency to be very stuffy I agree.

[Midnight Sun]

32C, Pershore, Worcs on August 2nd.

[richarddx7]

I will revise my estimation I think. 28.5C on 17th July, LHR. Just over the max reached temperature for May which I think was 28.2c somewhere.

Edited June 2, 2008 by richarddx7

[acbrixton]

Greenwich_1971.doc

Seems like late August should be better favoured for heat than in the recent records in the UK. The North Atlantic reaches its warmest values around late August or early September, and the hurricane season is often well underway by late August, something that should reinforce the heights and thicknesses over western Europe.

Roger, a few thoughts on this...

1. During August there is a marked reduction in the length of daylight and the height of the sun above the horizon: for London daylight declines from 15h 23m to 13h 36m and the height of the sun at solar noon declines from 56.4 to 46.9; this alone would account for a tendency for the hottest spells in August to occur earlier rather than later in the month.

2. SSTs reach a maximum of about 17.5-18c in the central/eastern Channel and southern North Sea by late August but are only about 1c less at the beginning of the month. Furthermore as most of our hottest weather comes from a direction between south and east-southeast the impact of SSTs is limited.

3. I would have thought that the main impact of hurricane activity is to intensify Atlantic depressions to our west and north west.

4. There is a marked difference in the nature of August weather between the north west and south east of the UK. I attach (courtesy of the UKMO) data for Greenwich and Aldergrove for 1971-2000. Note that whilst at Greenwich August is the sunniest month it is the 5th sunniest month at Aldergrove and that whilst August has the second lowest number of wet days at Greenwich Aldergrove has the 7th lowest number of wet days. In terms of rainfall totals Greenwich has the 6th lowest whilst Aldergrove has the 7th lowest total: my guess is that taking into account Greenwich's sunshine and wet days that this relatively high rainfall figure is primarily due to convective rather than frontal activity. My guess is that this indicates an increase in the number and intensity of Atlantic depressions throughout August the direct effects felt primarily to the north west. I suspect that there is, however, an indirect effect in the south east. I assume that most (not all) of out hottest weather occurs when there is persistent low pressure to the west of Ireland and high pressure to our east. The increase in frontal activity to the north west would reduce the chances of that synoptic set-up and would suggest that the south and south east would benefit more from ridging of the Azores high than high pressure to the east.

5. Finally even in the south east the awakening of the Atlantic, evident throughout August in the north west, will start to have a direct effect by the end of August as shown by data for September for Greenwich.

regards

ACB

[damianslaw]

Traditionally the warmest period of the year occurs between the 20th July and 10th August, to not have at least one very warm spell i.e. temperatures nearing or just above 30 degrees during this period I would guess is not a common occurance.

[Scorcher]

I will revise my estimation I think. 28.5C on 17th July, LHR. Just over the max reached temperature for May which I think was 28.2c somewhere.

Are you serious? That would be the coolest high temperature in a year since 1974, there is absolutely no chance of it happening IMO. It's also worth noting that 1993 is the only year since 1981 that 30C has not been reached in the UK so I think the odds definitely favour 30C+ somewhere during the summer.

Edited June 3, 2008 by Scorcher

[Roger J Smith]

Thanks ACB for that detailed response.

I guess my only point really is that late August should be holding up its end a bit more than it seems to do, but I would never be looking to it for much more than two or three yearly extremes per decade, seems more like zero to one at the current pace.

Your all-time record high currently developing over n TX, KS and OK :lol: where it was 41-42 C today. Now comes the hard part.

[J07]

Are you serious? That would be the coolest high temperature in a year since 1974, there is absolutely no chance of it happening IMO. It's also worth noting that 1993 is the only year since 1981 that 30C has not been reached in the UK so I think the odds definitely favour 30C+ somewhere during the summer.

But given the Met Office stats, 2007 came nail-bitingly close to not making it over 30C!