Stu_London

Much depends on whether 11.9 is rounded up or down. To achieve a full 0.1C rise we would need an average of about 15C (or maxes of 21-23C today) - With 17C widely forecast in the CET zone today, I would suggest the most likely outcome is that it remains the same.

A small drop again overall is the most likely scenario.

Another fall is likely today, although at this stage of the month and changes to the overall figure will be subtle. I think we can be fairly sure (barring any freaks of nature) that we will end up between 11.9 and 12.1 at month end.

Apparently it went down from 12.25 to 12.15 - not sure where this data is Not surprising at all really as the only way to get very low CETs in May would be very low minimas which would only occur under clear skies A look at the archive charts for May 1996 show that High Pressure over Greenland frequently ridged towards the UK and at that time of year that is the coldest sympnotics you can get. There was an easterly as well for a few days (which might not have been that cold). Things turned a bit more mobile in the last third of the month but it never really warmed up until the very end of the month.

Looking at the available output I am tempted to revise this down slightly however in the interests of people not whinging about changed predictions, I will stick with it. I think any hot spells are a way off yet. We could be about to see a run of months (with August like to buck the trend) where the CET is lower that that of last years value. I would be willing to put money that May, June, July, September, October and November will all come in less than 2006. If the SSTa data is to be believed then this may extend to December, January and February too. I know some will laugh at this suggestion, however what I am predicting is not actually that remarkable and I will be the first to revisit whether right or wrong

14.7C

12.2C for 1st May to 23rd May Probably only one more day of growth before it drops back - although the fall will be very slow at this late stage Very happy with my 11.9C prediction - i expect to be within 0.2C although there still remains some uncertainty in the ensembles for London at quite short range.

wow your a legend

Still quite a largish range to play for considering we are so far into the month. Quite a large ensemble scatter even after 48 hours with two members staying well above average until the end of the month (0z). Somewhere as high as 13 could be achieved if those two came to fruition. Here is one for Kevin (Mr D) During spring - has there ever been 2 half months that have been cooler than the previous half month. For example: 2nd Half of May, cooler than 1st half of May, which was cooler than second half of April This is looking a possiblility now. Could reverse the question to warming for the autumn months also.

1st - 21st - 12.0C - spot on so far, although I think the 24th will be nearer the top of the range. Still some very cool temps progged around the BH weekend - GFS saying no more than 11C for the CET zone for maximas. I am just glad that I am off to Cyprus for the weekend.

Probably a bit of both this month - however in recent history I would suggest the source of the air to be the overriding driver as this has also influence the daytime maximas

Has been a very wet month to date (198% of average) which would definately alter perceptions especially as all of the rain has come after 6th May Daytime temps have been just above the 71-00 mean (+0.7C) Nightime temps warmer (+2.0C) consistent with cloud cover at night. Thanks to climate.uk.com for all data Sypnotics have been the driver again with no northerly from a cold source

Latest Manley figs to the 19th (thanks to www.climate-uk.com) show 12.1C to the 19th. Where it goes in the last 12 days could be quite varied depending on which ensemble member you beleive. Things do look like warming up aloft from the 21st to the 25th but this also corresponds with a dry spell which may see lower minima than of late helping to offset the maximums. From the 25th a cooldown is likely with most of the period (based on 00z GFS ensembles) slightly below the long term mean - however this also corresponds with less settled conditions. If the weather activitiy is largely frontal then expect the CET to rise slightly. If it is more of a showery nature then a slight drop could be expected as skies tend to clear during the hours of darkness. I could do a graph like SF but can't be bothered, however the ranges I see by assorted dates from now to the end of the month and my personal hunches for each date are as follows: - 21st - 11.9 to 12.1 (prediction 12.0) 24th - 12.0 to 12.5 (prediction 12.2) 27th - 12.2 to 13.0 (prediction 12.5) 29th - 12.0 to 13.2 (prediction 12.4) 31st - 11.9 to 13.5 (prediction 12.4)

I don't honestly see it being much different to where we are now to be honest. We are due a few days of cooler days and nights which may knock it back slightly to maybe 11.8C In the absense of a proper heatwave in the last week of May (which GFS seems to have backed away from) then even if it was a bit warmer than now the average would only creep up very slowly. Remember the last few days of April which were very warm against the average - confident predictions of around 11.5 were made, however it only crept up painfully slowly.

Its also fair to say the actual weather has an effect on our perception Having been quite dull and quite wet, we would naturally associate this with cooler weather. However that is not necessarily the case, especially with regard to night time temperatures

To be fair there wasn't any real warmth in the near term or longer term until ex sub TD-Andrea popped up later yesterday from knowwhere. Prior to that it was average then cooler. Reassessing things now, its looks as if we will be warm and wet, cooler and dryer and then there appears to be a definate trend to warm to hot conditions in the last week of the month. However this is factoring in a pattern change that has only appeared in the last two runs and needs to be nailed down - also this is a little far away to be putting detail on just yet. As for predictions, 12.5 would be near the top end of what I would think to be likely at this point

I agree it's unlikely to be cooler than April, although much will depend on how much it can dip in a below average period that may last until around 21st of the month. If there is no heatwave in the last 3rd it could be game on!

I don't either, but it may be quite a close run thing

11.9C for the period 1st to 13th May. Can't see much change in the next 4-5 days, then GFS goes for a cooler period from the 19th for a few days The warmest spring record is looking much less likely but May cooler than April anybody? Longshot - will depend largely on the nighttime minimas during the alleged cooler spell. Rainfall looks like hitting the average for the month today, so with the unsettled theme looking like continuing May could be a very wet month indeed, also very much in contrast with April. Data from P Edens excellent climate UK site.

If you look at Philip Eden's statistics for the 1st - 10th of May then you will note that there are regional splits. These seem to suggest that to the north and east of the CET zone things were slightly less above average in this period, though still above average nonetheless. Although the sypnotics of May so far have not been spectacularly warm it should be remembered that we had residual heat from the end of April to clear - firstly in the atmosphere, which took around 3-4days and latterly in residually high SSTs around our shores which have been modifying our temperatures. I am sure that had April ended "average", we would have been about average for May now. Looking forward and taking the ensembles at face value, there would appear to be little scope of any very warm or hot weather in the foreseeable future, however no sharp drop in the CET is likely either as there appears to be lots of rainfall on the agenda, which probably means wind and cloud meaning we lose the ability to record any very low minima.

For me from my memory it would have to be as follows: - Jan - 1987 - The most remarkable weather I have witnessed in this country Feb - 1986 - Cold but not snowy for most - however i was in the west country at the time which was sometimes the battleground - honourable mention to 1998 when I managed to have a decent BBQ with shorts and t shirt on. Mar - 1987 - Late snow Apr - 2003 - Lovely low humidity & sunny - better than 2007 in my opinion May - 1989 - Start of a nice summer. Jun - 2006 - Perfect summer weather Jul - 1983 - Very warm and very stormy in the south west - one storm last 2 hours with hundreds of visable lightning strikes. Aug - 1990 - Day after day of beautiful summer weather Sep - 2006 - Very nice thank you Oct 1987 - The second most remarkable weather event I have witnessed in this country - sorry for the lives lost but as a weather phenomena, the pressure and temperature reading around the storm were amazing. Nov 2005 - Really enjoyed the swift transisition from warm to cold - Best Greenland high witnessed for ages too. Dec 1981 - Lots of snow which was still there at xmas - crazy temperatures too. As for the seasons Winter - 78/79 - couldn't remember well enough to pin the months down on this but remember many mornings of snow piled up close to 1 ft deep Spring - 2003 - Nice Summer - 1976 - Blue sky thinking Autumn - 1987 - Tricky to pin down but the great storm wins it Best Year? 2003 - 38C the day I chose to lay laminate flooring at home - also the day I joined net weather. As for 1995 - summer was good in the south east but better in the west and we got more snow in central london in 2006/2007 than 1995/1996

It is certainly true that man made and natural aersols (spelling?) can induce some cooling. Examples of these are volcanic ash and pollution which one would assume could include that from a nuclear explosion. It was interesting that our April warm weather spell co-incided with some of the cleanest pollution levels at Northern latitudes ever measured. Perhaps the Iranians can help us all out in the near future.

Nice post Tamara - I agree with some of it but would say all of it is well presented One small piece of pendantry - if we are going to talk about posts going off topic then should we not look at where this thread was placed in the first place. I for one feel too many threads such as the monthly and annual CET are hijacked and good thread that this largely is, I think the forum on environment change would be more appropriate.

Just to get this post in perspective, the warm start to the month is largely due to the 850s starting the month about 4C above the 30 year mean - althought this was actually on a cooling trend from the 8-10C above average that most of the second half of April had. The graph on Philip's site shows this quite clearly. Also the 2C Above average relates to the average first few days of the month not the whole of May. The trend has continued and we are now about average but the +2C is largely residual from the long warm spell that typified April. There is no ridge (in the reliable timeframe) indeed the unsettled weather continues for some time and there is a hint that daytime temps may drop off a few more degrees. Where the CET goes in the short to medium term will partly be dependant on whether cloud and wind ease off to allow for some chillier nights. However, I would be surprised if it is still above 12C this time next week.

My point was that warming had reappeared in the UK climate in the last 13 months at a great pace which was extraordinary given that we were at a warm start point anyway - so essentially we are saying the same thing. I am not a cold lover by the way and I am not in denial about the climate warming. I think energy conservation and other green issues are very sound thinking, however not necessarily linked to climate. But I also think that laying the blame at C02 emissions and citing a couple of hundreds years worth of statistics is akin to claiming to see the whole picture when one is in fact, holding a jigsaw piece in front of them.