May CET -- Your Forecasts

[damianslaw]

Wouldn't be surprised to see a marked downward correction this year, the CET seems a little high in my opinion. Can't see the CET moving much in the coming days but we are probably going to break the 10 degree mark early next week, consequently the chances of a sub 10 degree month are looking less likely, whilst a sub 11 degree month still looks very high indeed so still very much odds on a below average month.

[Kentish Man]

Hadley has updated - 9.6C up to 15th May.

[Village]

My forecast is cold, cold and more cold.....dont expect any warmth until June.

[The PIT]

Big differance again here we're at 8.7C while the CET zone is at 9.6C. The coldest I recorded is 9.4C so an outside chance of that being beaten but unlikely.

[Roger J Smith]

The coldest second half of May data were posted above, so I had a look at the coldest last ten days of May (which would be 22nd to 31st). The two coldest periods with their coldest day were:

7.6 in 1821 (4.6 on the 26th)

8.6 in 1923 (6.6 on the 24th)

The last time this period was below 10 C was 1975 (9.6 C) and recently it was 10.6 in 2000, 10.9 in 2006. There was a daily reading of 6.6 C on the 27th in 1984 and it was 7.1 on the last day of May in 1975

Other notable cold days in late May include 4.9 on 30th in 1807 (this came five days after a very warm 19.8 . Something very similar happened in 1855 (30th 5.8, three days earlier it had been 17.4).

It was particularly cold around 17-18 May 1891 with CET means of 4.3-4.5 C. This cold spell lasted to almost the end of the month but the period 22-31 May missed the record low slightly

Edited May 16, 2012 by Roger J Smith

[Roger J Smith]

22nov10blast asked about coldest 16 April to 15 May. The filter shows these results:

1. 6.5 (1782)

2. 6.6 (1879)

3. 7.0 (1877)

and since 1980, 7.8 in 1991.

The warmest was 12.7 (1893), second place 12.5 (1776) and third to last year (2011) at 12.4

[Relativistic]

22nov10blast asked about coldest 16 April to 15 May. The filter shows these results:

1. 6.5 (1782)

2. 6.6 (1879)

3. 7.0 (1877)

and since 1980, 7.8 in 1991.

The warmest was 12.7 (1893), second place 12.5 (1776) and third to last year (2011) at 12.4

Thanks. It's interesting to see that the two warmest were actually in less recent times.

[Roger J Smith]

Yes, now that you mention it, almost a periodic return, 117 years followed by 118 years. Another similarity, all three had cold winter months trending early winter, Jan 1776 was -1.6, Dec 1892 was 1.8 and of course Dec 2010 was -0.7.

These analogues have not kept pace since although divergence has been a lot less than complete (no very mild Novembers in the first two cases) but winters of 1777 and 1894 had some moderately cold months and some kind of out of phase trend in spring that involved a cold April in 1777 and a cold May in 1894. Seems like some kind of QBO-length signal was in phase -- as the QBO tends to be variable in the range of 2 to 2.5 years, this is not always very useful for analogue forecasting for too long anyway, but FWIW the summers of 1777 and 1894 were both in the "near average" category and then winters that followed were cold, 1895 exceptionally so.

I have been working on a summer forecast to update the posted spring forecast (seasonal thread). It does not look very far from average in general. Will be posting that some time tonight or Friday morning.

[Relativistic]

Yes, now that you mention it, almost a periodic return, 117 years followed by 118 years. Another similarity, all three had cold winter months trending early winter, Jan 1776 was -1.6, Dec 1892 was 1.8 and of course Dec 2010 was -0.7.

These analogues have not kept pace since although divergence has been a lot less than complete (no very mild Novembers in the first two cases) but winters of 1777 and 1894 had some moderately cold months and some kind of out of phase trend in spring that involved a cold April in 1777 and a cold May in 1894. Seems like some kind of QBO-length signal was in phase -- as the QBO tends to be variable in the range of 2 to 2.5 years, this is not always very useful for analogue forecasting for too long anyway, but FWIW the summers of 1777 and 1894 were both in the "near average" category and then winters that followed were cold, 1895 exceptionally so.

I have been working on a summer forecast to update the posted spring forecast (seasonal thread). It does not look very far from average in general. Will be posting that some time tonight or Friday morning.

That is very interesting, certainly not something I picked up on. Let's see if Summer and Winter pan out similarly.

Just to add, looking back another 117 years we don't see this Spring warmth. It's a shame we don't have records going back a few years further to see if the Spring warmth was a theme in years just prior to 1659.

However, as you mentioned, looking a year on from each of those years and we see that April 1777 also came in at 7.2C on the CET, as did this year, and May 1894 came in at 9.2C, which is similar to the current CET, although this years will probably finish higher.

Edited May 18, 2012 by 22nov10blast

[DAVID SNOW]

9.5 degC (-1.2) to 16th May

http://www.metoffice..._info_mean.html

Steady as she goes(for now) 9.5 to the 17th May.

[damianslaw]

CET should rise appreciably in the coming days, the chances of a significantly below average month now look very slim, but the odds of a below average month overall are still a bit higher than an above average month. Could be another month of two halves a bit like Feb but no way near to those extremes. We've seen quite a few Mays with two contrasting halves and very recently in 2008 and 2011, on thos occasions unusually the first half was much warmer than the second half.

Sunshine levels this month have been preety poor it has to be said, the sun by the second half of May is every bit as strong as in mid July, so any high pressure development near the country at this time of year does absolute wonders for temperatures, every bit as high as what can be experienced in peak summer warmth period of mid July to mid August.

[J10]

CET should rise appreciably in the coming days, the chances of a significantly below average month now look very slim, but the odds of a below average month overall are still a bit higher than an above average month. Could be another month of two halves a bit like Feb but no way near to those extremes. We've seen quite a few Mays with two contrasting halves and very recently in 2008 and 2011, on thos occasions unusually the first half was much warmer than the second half.

Sunshine levels this month have been preety poor it has to be said, the sun by the second half of May is every bit as strong as in mid July, so any high pressure development near the country at this time of year does absolute wonders for temperatures, every bit as high as what can be experienced in peak summer warmth period of mid July to mid August.

Massive regional variation in sunshine values this month, the past week has seen a lot of sunshine is some western areas, with quite a few cloud free days.

If next week is warmer again, this follows some months in recent years, when it has been cold for the most part but a late warm spell takes it close to average, especially used to happen when we tried to get above 3c in winter.

[TonyH]

It will be interesting to see if we can creep up to the average in the last 10 days, hope so I went for 12.0c!

[Summer Sun]

9.6 to the 18th -1.2, that should change during the coming week hopefully we could be looking of a CET finish of around 10.3 to 10.7c

[BornFromTheVoid]

Minimum today is 7.8C while maxima are likely to be just over 12C, so remaining on 9.6C for now.

From tomorrow, the 06z GFS will have the CET at

9.6C to the 20th (9.8]

9.7C to the 21st (11.8]

9.9C to the 22nd (13.6)

10.2C to the 23rd (15.7)

10.5C to the 24th (17.9)

10.7C to the 25th (15.2)

10.8C to the 26th (14.9)

With end of month corrections, probably 40/60 against reaching the the 61-90 or 71-00 average.

Almost certain stay below the 81-10 average.

[The PIT]

Next week could be interesting. If the cloud and mizzle hangs on the in the east you're going to have a large difference in the end of month values between east and west.

[damianslaw]

Next week may see some quite chilly nights despite the rather warm uppers thanks to the clear skies and light winds - but probably a shortlived affair as the easterly wind kicks in preventing low minima.

I'm expecting the CET to be close to 11 degrees as we enter the last week, but I still think we will see a below average CET not by much which will mask how the cold the first half of the month has been especially in the north.

[Summer Sun]

CET remains at 9.6c to the 19th

[Relativistic]

It looks like Corbyn's prediction won't come off now, although it was fairly accurate for the first 20 days, not quite as cold as he said though. We still experienced the northerlies and the snow that he mentioned.

[Jack Wales]

Significant insrease in temperature over the next week or so. This could add at least 2C to the final outturn.

Edited May 20, 2012 by Jack Wales

[damianslaw]

Not that it is, but if the synoptics this month had occured in Jan or Feb then a very cold month would have been the order of the day , northerlies and slow moving trough followed by a deep seated easterly... even April the upcoming spell would probably be a rather chillier affair. Alas we are now in late May when easterlies mean warm and often stable weather.

[BornFromTheVoid]

9.6C to the 20th

http://www.metoffice.gov.uk/hadobs/hadcet/cet_info_mean.html

Yesterday was 9.8C. Minimum today is 6.3C, while maxima look like being around 16C, so an increase to 9.7C likely tomorrow.

After that, thing begin to rocket upward, with the 06z GFS having the CET at

10.0C to the 22nd (15.4)

10.3C to the 23rd (17.0)

10.6C to the 24th (18.4)

10.9C to the 25th (17.4)

11.0C to the 26th (12.9)

11.0C to the 27th (12.2)

11.1C to the 28th (14.0)

Reaching the 61-90 and 71-00 mean looking somewhat likely now, before corrections at least. No chance really of reaching the 81-10 May average though.

11.0-11.4C after corrections?

[Don]

Reaching the 61-90 and 71-00 mean looking somewhat likely now, before corrections at least. No chance really of reaching the 81-10 May average though.

11.0-11.4C after corrections?

Yes, a very close to average month looking likely now. I know many were fed up with the cool and unsettled weather of the last 7 weeks, but it would have been nice to have had two below average months in a row after the long run of above average months (apart from February) since August!

Edited May 21, 2012 by Don

[Relativistic]

Yes, a very close to average month looking likely now. I know many were fed up with the cool and unsettled weather of the last 7 weeks, but it would have been nice to have had two below average months in a row!

Totally agree, could still happen though (just).

[DAVID SNOW]

Totally agree, could still happen though (just).

Still a good chance of sub 11 imo.