May 2018 C.E.T. forecasts and optional EWP contest

[Summer Sun]

12.1 to the 20th

1.4 above the 61 to 90 average

0.9 above the 81 to 10 average

[BornFromTheVoid]

Here's the forecast based on the 06z GFS

Rolling CET... Anomaly to 81-10 rolling avg (Daily Avg: Anomaly to 81-10 daily avg)

12.3C to the 21st... +1.1 (14.5 +2.4)
12.4C to the 22nd... +1.2 (15.5 +3.3)
12.5C to the 23rd... +1.2 (15.0 +2.2)
12.6C to the 24th... +1.2 (15.0 +1.7)
12.7C to the 25th... +1.3 (15.4 +2.9)
12.9C to the 26th... +1.4 (17.1 +4.7)
13.0C to the 27th... +1.5 (16.0 +3.9)
13.1C to the 28th... +1.6 (16.2 +3.9)
13.3C to the 29th... +1.7 (16.6 +3.8)
13.5C to the 30th... +1.8 (19.2: +6.1)

A variation between warm and very warm seems most likely for the remainder of the month, with the CET climbing accordingly. Still no more daily records under threat, but that requires means in the high teens or low 20s at this time of year.

[Roger J Smith]

Give a friendly wave as we go by about 80 out of 359 previous Mays (12.1 has 13 tied between 80th and 92nd warmest).

We cannot reach the leader 15.1 (1833) without averaging almost the warmest May day on record (21.2). If we averaged the late May daily record values (around 20) then we would end up at 14.9. If we averaged the weakest daily records (19) that would get us to 14.5. To edge past second place 1848 (13.9) we would need to average 17.5 today to 31st. To join the tie at third (13.8 in 1758 and 1788) we need to average 17.0. Looks to me like we might get as high as fifth place 13.7 (1808) or sixth place 1727 and 1992 (13.6). Corrections might bring 2018 back down out of the top ten (currently there is a four way tie for 8th at 13.5). 

Last year was 13.2, but we won't be close to beating the previous record for consecutive Mays as 1834 managed a 13.0 (15.1 previous year, average 14.05). I think we might have difficulty making second place on that list, 1726-27 (13.4, 13.6, average 13.5). 

[The PIT]

Sunny Sheffield up to 13C +2.4C above normal. Rainfall unchanged. 

[BornFromTheVoid]

What a remarkable 12z! If it comes off, the final 5 days of the month will average close to 20C and we'd have a genuine shot at beating the warmest May day on record, at least twice!

[The PIT]

17 minutes ago, BornFromTheVoid said:

What a remarkable 12z! If it comes off, the final 5 days of the month will average close to 20C and we'd have a genuine shot at beating the warmest May day on record, at least twice!

Hopefully it won't however I'll be off that week so will be able to cope with the heat much more easily.

[Roger J Smith]

This year has slight 1947 tendencies, it would seem -- impressive cold and snow end of Feb into early Mar, then wet, our April was warmer but now this -- most notable early heat wave was something like 29 May to 4 June 1947 which set June daily record at wrong end of month after narrowly missing the May record. 

That 12z warm spell looks good but a bit of convective debris might hold down some daily maxima if it were to prove entirely accurate (at this time scale, unlikely, the trend is my friend). 

[Ice Man 85]

4 hours ago, The PIT said:

Hopefully it won't however I'll be off that week so will be able to cope with the heat much more easily.

You have a hollowed-out american style chest freezer?

[Summer Sun]

12.3 to the 21st

1.5 above the 61 to 90 average

1.1 above the 81 to 10 average

[Man With Beard]

18 hours ago, Roger J Smith said:

Give a friendly wave as we go by about 80 out of 359 previous Mays (12.1 has 13 tied between 80th and 92nd warmest).

We cannot reach the leader 15.1 (1833) without averaging almost the warmest May day on record (21.2). If we averaged the late May daily record values (around 20) then we would end up at 14.9. If we averaged the weakest daily records (19) that would get us to 14.5. To edge past second place 1848 (13.9) we would need to average 17.5 today to 31st. To join the tie at third (13.8 in 1758 and 1788) we need to average 17.0. Looks to me like we might get as high as fifth place 13.7 (1808) or sixth place 1727 and 1992 (13.6). Corrections might bring 2018 back down out of the top ten (currently there is a four way tie for 8th at 13.5). 

Last year was 13.2, but we won't be close to beating the previous record for consecutive Mays as 1834 managed a 13.0 (15.1 previous year, average 14.05). I think we might have difficulty making second place on that list, 1726-27 (13.4, 13.6, average 13.5). 

I'm not so sure we can't get second place Roger, seeing the charts of the past 24 hours!! Must be a outside chance of averaging 20C on several consecutive days next week!!

[The PIT]

Sunny Sheffield at 13.2C +2.5C above normal. Rainfall unchanged. Only a small increase tomorrow as the Max temp are a bit down from previous days.

[Roger J Smith]

This is part of the report on CET averages and extremes that I post around the 2nd of each month to assist Summer Sun in his daily tracking of the CET anomalies. For some reason I added the table of top ten May daily CET values. I have now edited the portion of that post from tomorrow's date to end of the month, the top ten, and I have added the summer stats for the various years mentioned just for interest. I added September CET because the first half (or 21 days) of that month can often be considered summer-like and some years have their daily maximum in September. If the May daily value was the warmest of the year, the warmest after 31 May is shown in brackets and italics. 

 

__ Date __ Highest ___ That year's summer CET and max daily

___ 22 ___ 19.5 1918 ___ 13.3 _ 15.4 _ 16.1 _ 11.9 ___ 21.0 on 22 Aug

___ 23 ___ 19.5 1922 ___ 13.8 _ 13.7 _ 13.6 _ 12.2 ___ (18.6 on 1 June)

___ 24 ___ 18.8 1953 ___ see next entry

___ 25 ___ 21.0 1953 ___ 14.4 _ 15.5 _ 16.2 _ 13.8 ___ 22.0 on 12 Aug

___ 26 ___ 18.7 1784 ___ 13.7 _ 15.2 _ 14.0 _ 14.8 ___ 20.3 on 7 July

___ 27 ___ 19.0 1788 ___ 15.4 _ 15.8 _ 15.8 _ 13.4 ___ 20.4 on 12 July

___ 28 ___ 20.6 1847 ___ 13.9 _ 17.5 _ 15.2 _ 11.5 ___ 22.5 on 14 July

___ 29 ___ 21.2 1780 ___ 14.2 _ 16.8 _ 17.6 _ 15.6 ___ 21.8 on 1 Sep

___ 30 ___ 21.0 1944 ___ 13.5 _ 16.5 _ 17.0 _ 12.5 ___ (19.8 on 18 Aug)

___ 31 ___ 20.5 1947 ___ 15.5 _ 17.0 _ 18.6 _ 14.9 ___ 23.0 on 3 June

___________________________________________________________________________

Top ten for May and all 20.0+ __ Summer data if not in records list above

 1. 21.2 (29th, 1780) ___ see above

 2. 21.1 (29th, 1944) ___ see above

 3. 21.0 (25th, 1953), 21.0 (30th, 1944) __ see above

 5. 20.8 (29th, 1947) ___ see above

 6. 20.6 (28th, 1847) ___ see above

 7. 20.5 (31st, 1947) ___ see above

 8. 20.4 (19th, 1868) _____ 15.5 _ 18.3 _ 16.8 _ 14.3 ___ 23.2 on 22 July

T9. 20.0 (15th, 1833) _____14.6 _ 15.8 _ 14.3 _ 12.1 ___ (20.0 tied on 28 July)

T9. 20.0 (16th, 1808) _____14.8 _ 18.4 _ 16.7 _ 12.7 ___ 24.5 on 13 July

T9. 20.0 (31st, 1781) _____ 16.2 _ 17.4 _ 17.3 _ 14.2 ___ 20.9 on 1 June

__ added top six May CET not in lists __

year ____ May max _____ summer data

(1848) ___ 17.2 ________ 14.5 _ 15.6 _ 13.6 _ 12.8 ___ 20.5 on 6 July

(1758) ___ unkn ________ 14.6 _ 14.2 _ 16.4 _ 11.9 ___ unknown

(1727) ___ unkn ________ 14.9 _ 16.9 _ 16.9 _ 14.4 ___ unknown

(1992) ___ 18.8 ________ 15.7 _ 16.2 _ 15.3 _ 13.4 ___ 20.4 on 29 June

_____________________________________________________________________________

In researching that list, found this remarkable sequence in May 1807 ... 19.8 on 25th (record for date is 21.0 in 1953) to 4.9 C on 30th (record minimum).

It is also interesting to note that all of these warm days occurred before or during May 1953. 

The warmest May day since the end of May 1953 has been 19.4 (31 May 1978). The warmest since then was 18.9 (31 May 2003). 

We seem very overdue for some record warmth in mid to late May to add some more 20+ days to this list. 

When the all-time April record of 19.7 was set in 1775, these are the only days that year with a higher average CET ... 20.4 on 6th June, 21.1 on 21st July, 

___________________________________________

for the years mentioned in that section

1775 ______________________ 16.6 _ 16.7 _ 15.8 _ 14.3 ___ 21.1 on 21 July

1807 ______________________ 14.2 _ 17.1 _ 16.9 _ 10.5 ___ 21.2 on 22 July

1978 ______________________ 13.7 _ 14.8 _ 15.0 _ 14.2 ___ 19.6 on 01 June

2003 ______________________ 16.1 _ 17.6 _ 18.3 _ 14.3 ___ 23.9 on 09 Aug

______________________________________________________

The overall average values of these summer data are:

(average all cases) ___________ 14.7 _ 16.4 _ 16.0 _ 13.3 ___ 21.3

Brief summary:

There is quite a mixture of summer types following these instances of late May warmth. There are a few very good summers in the mix and a couple of very poor summers. But the overall signal is quite average once the late May warmth comes and goes. There is a tendency for that warmth to be extinguished from the data by the second week of June (the first week of June generally averages 2-3 above normal).

So there are no real clues about how summer 2018 might turn out from the medium-range forecasts of May heat alone. With 1922 and 2003 in the data set, nothing much is ruled out. 

 

 

 

[cheeky_monkey]

sunny Edmonton has had a big jump to 14.9c which is nearly 3.5c above normal...another hot week in prospects with heat warnings now in affect until the weekend.

[damianslaw]

Oooh outside chance might see two date records for May bank holidays - unheard of.. anyone have stats for Whit May highest maxima recorded? 

When was the last time we had back to back significantly above average temp bank holidays - we are being spoilt.. the effects of the SSW I wonder and the way Spring started - its been an unusual Spring, one of two halves, first half predominantly wet and cold and dull, second half predominantly dry sunny and warm. 

[Summer Sun]

12.4 to the 22nd

1.6 above the 61 to 90 average

1.2 above the 81 to 10 average

[summer blizzard]

What sunshine records are we looking at?

 

[Roger J Smith]

Good question, I would appreciate it if somebody in the know could link to the source of sunshine records in the UK. 

My wild guess would be that the record high value for May at any location would be around 300 hours. The average is probably a little under 200.

[The PIT]

Sunny Sheffield at 13.3C +2.5C above normal. Rainfall still at 15.9mm 27.6% of normal. 10 days without any measurable rain now.

Edited May 23, 2018 by The PIT

[Summer Sun]

12.5 to the 23rd

1.6 above the 61 to 90 average

1.2 above the 81 to 10 average

[Mapantz]

19 hours ago, Roger J Smith said:

Good question, I would appreciate it if somebody in the know could link to the source of sunshine records in the UK. 

My wild guess would be that the record high value for May at any location would be around 300 hours. The average is probably a little under 200.

This is what I used to obtain data from Bournemouth and Swanage; https://www.metoffice.gov.uk/public/weather/climate/gbyxgmvts

I took all the rain, temp and sunshine records for both those stations, and then got a derived average.  I live in between those Met Office stations, so it made sense to get an average which I can compare my own data to.
For example, the combined average sunshine hours for those stations comes out at 219hrs. I'm currently sat at 204.2hrs. 

[The PIT]

No change sunny Sheffield either rainfall wise or temperature wise. 11 days without measurable rain.

[Summer Sun]

12.6 to the 23rd

1.7 above the 61 to 90 average

1.2 above the 81 to 10 average

[BornFromTheVoid]

Here's the forecast based on the 06z GFS

Rolling CET... Anomaly to 81-10 rolling avg (Daily Avg: Anomaly to 81-10 daily avg)

12.6C to the 25th... +1.2  (14.6: +2.1)
12.8C to the 26th... +1.4  (17.5: +5.1)
13.1C to the 27th... +1.6  (18.8: +6.7)
13.2C to the 28th... +1.7  (18.5: +6.2)
13.4C to the 29th... +1.8  (17.3: +4.5)
13.5C to the 30th... +1.9  (18.0: +4.9)
13.7C to the 31st... +2.0  (17.5: +4.2)

So after a week with many runs suggesting record breaking heat, we are now back to where we were on Monday, warm but not exceptionally so. In fact, the latest forecast has no daily records, not even a single day above 19C, while several runs during the week saw the warmest day record for May get smashed!
As things stand, 13.7C (13.67C) is current estimate before corrections. Realistically, this could vary from 13.4C to 13.9C before corrections, then 12.9C to 14.0C after corrections. That's a range of 2nd warmest on record down to 24th warmest

[The PIT]

Sunny Sheffield up to 13.4C +2.4C above normal. Rainfall up 17.6mm 30.5% of average

[Snowyowl9]

Seen some cold nights this month with some late ground frosts 2.4c one night.