May 2021 C.E.T. and EWP forecast contests

[Roger J Smith]

1 hour ago, Relativistic said:

Provisionally, the highest daily mean of the meteorological Spring is still the 31st March's value of 14.3C. Can we make it to the end of May without recording a higher daily mean? Can't have been many years where the highest was in March.

It has only happened once, since daily data started in 1772, and that was in 1957 with 13.4 C on 12 March followed by 12.8 C maxes in both April and May. 

Other than that, the closest was within 1.1 C in 1777 (14.8 on 27th March, finally edged out by 15.9 on 30 May). That year the March surplus lasted to 28 May which hit 15.4, April had only managed a maximum of 12.5 and the margin was greater than 1957 until 14.5 on 25 May cut it to +0.3. 

Third place in this odd contest goes to 1815 (13.8 on 31 Mar) which was eventually beaten by 1.3 C by 15.1 C on 28 May. This one lasted to 11 May when it was 14.6. 

Fourth place belongs to 1923 at 1.5 C  -- 13.5 on 27 March followed by 15.0 on 3rd and 4th May. 

Fifth is a tie between 1899 and 1938 at 1.6 C. -- 1899 was running 1.2 from only 11.6 in March until 31 May raised it to 1.6; and 1938 rode the warmth of 30 Mar (13.1) through a cool April to the warmest spring day, 14.7 C on 14 May.

Seventh is more recent -- 2004 at 1.7 C. -- 13.2 on 16 Mar, 14.9 on 19 May. Unlike most this one also had a warmer day in April (13.7 25th).

Eighth was 1819 at 2.1 C. -- 12.0 on the 31st Mar was eventually topped by 14.1 on 3 May. 

(the all-data average for this stat was 6.1 C, in other words, on average April or May improves on the March daily max mean by 6.1 deg. 

[Roger J Smith]

That 1957 run ended on 1st of June when it reached 14.6 C. 

[The PIT]

Sunny Sheffield still at 9.2C -2.0C below normal. Rainfall 126.4mm 212.1% of the monthly average

[Roger J Smith]

EWP looks to be near 112 mm with 102 to 22nd and about 10 mm on average yesterday (southwest, Wales and northwest above that, rest below). 

GFS adds about 15 mm more, target is 127 mm. 

Rumours of 20 C max by 31st, but running out of time to jack up the CET by much anyway, especially with slight increases. 

[feb1991blizzard]

On 21/05/2021 at 18:24, BornFromTheVoid said:

Assuming a post corrections May CET of ~9.8C, the next big target becomes an April to June average of under 10C. This was last achieved in 1923, and would require a June CET under 13.7C this year (June <13.7C was reached quite recently too, in both 2012 and 2013)

I think it will be over 10c now, possibly 10.3c, still nowhere near my 11.3 though.

[Summer Sun]

9.6c to the 23rd

1.2c below the 61 to 90 average
1.7c below the 81 to 10 average

___________________________

Current high this month 9.7c on the 22nd
Current low this month 6.6c on the 1st

[damianslaw]

CET stuttering somewhat right now, but expect a slow rise through rest of May, expect we will just nudge into the 10s, but a downward correction especially if marked could see a finish in the 9s..

[Relativistic]

3 hours ago, damianslaw said:

CET stuttering somewhat right now, but expect a slow rise through rest of May, expect we will just nudge into the 10s, but a downward correction especially if marked could see a finish in the 9s..

Indeed, sub-10C may be on a knife-edge now. Would be a shame not to finish sub-10C as such Mays are rare -- there have only been nine since 1900!

Edited May 24, 2021 by Relativistic

[Weather-history]

Diametrically opposite months

May 2020

CET: 12.5C

EWP: 10.3mm

E&W Sunshine: 296.9hrs

 

May 2021

CET: ~10C

EWP: ~113mm (up to 23rd)

Sunshine: ? 

[The PIT]

Sunny Sheffield at 9.2C -2.1C below normal. Rainfall up to 127.5mm 213.9% of the monthly average

Should resume in the slow rise again from today the main drive at first being the night temperatures.

Using the local forecast and adjusting for the daytime temperatures being to low brings us to a closing value of 10.1C Using the predicted values gives us 9.8C

9.8C puts us in the top ten coldest Mays for Sheffield.

Quite surprised by how much it could go up by to be honest.

[Relativistic]

This'll be the first time since 2013 that at least three of the first five months of the year were below their respective 1961-90 averages. All five managed it in 2013. The last time exactly three of the first five months managed it was in 2010 (January, February, and May).

[Summer Sun]

9.6c to the 24th

1.3c below the 61 to 90 average
1.8c below the 81 to 10 average

___________________________

Current high this month 9.7c on the 22nd
Current low this month 6.6c on the 1st

[BornFromTheVoid]

Latest estimate from the GFS is a finish of 10.5C before corrections. The final 5 days average could be in the top 15% warmest on record, and the final 3 days just outside the top 5% and warmest since 2003.

[Don]

17 hours ago, Relativistic said:

Indeed, sub-10C may be on a knife-edge now. Would be a shame not to finish sub-10C as such Mays are rare -- there have only been nine since 1900!

Yes, a shame in many respects.  I know most want some warmer weather now, but it would have been good to get a sub 10C May.  Would be typical for the last few days of the month to scupper it!  I had a feeling as soon as a warm up to average was shown in the models, it would upgrade to warm!

[Don]

5 hours ago, BornFromTheVoid said:

Latest estimate from the GFS is a finish of 10.5C before corrections. The final 5 days average could be in the top 15% warmest on record, and the final 3 days just outside the top 5% and warmest since 2003.

Very warm weather is so easy to achieve these days, even after a prolonged very cool period, it just pops up out of nowhere!  Look at the 31st July last year!

[The PIT]

Latest GFS which also tends to under do the temperatures for here gives us a final figure of 10.4C still a long way below average. At the moment the CET zone is 0.4C above us so that would smack the final value at 10.8C.

Quite an impressive rise so late in the month.

[SummerShower]

The current high of 24.5 for the year is in March.. I think that is still a safe stat for the spring, but a slight chance of temperature forecasts upgrading a few days before could threaten it, just perhaps..

Realistically low 20s is  possible before month end, not 25c though I feel.

[Don]

2 hours ago, SummerShower said:

The current high of 24.5 for the year is in March.. I think that is still a safe stat for the spring, but a slight chance of temperature forecasts upgrading a few days before could threaten it, just perhaps..

Realistically low 20s is  possible before month end, not 25c though I feel.

Hmm, not so sure but I hope the high for spring!

[The PIT]

Sunny Sheffield back down to 9.2C, -2.2C below average, Rainfall 127.7mm 214.3% of the monthly average

Latest local run would see us end up at 10.1C for the month. Still an impressive rise for the month.

Edited May 26, 2021 by The PIT

[Summer Sun]

9.7c to the 25th

1.3c below the 61 to 90 average
1.7c below the 81 to 10 average

___________________________

Current high this month 9.7c on the 22nd & 25th
Current low this month 6.6c on the 1st

[Don]

4 hours ago, Summer Sun said:

9.7c to the 25th

1.3c below the 61 to 90 average
1.7c below the 81 to 10 average

___________________________

Current high this month 9.7c on the 22nd & 25th
Current low this month 6.6c on the 1st

Chances of a sub 10C final figure must be gone now?

[Roger J Smith]

EWP now close to 120 mm (was 117 mm for 24th), about 3 mm likely to be added for 25th. GFS six-day total for month's end about 10 mm more so 130 mm may be as high as we get, provisional scoring all okay except Shillitocettwo would move up about ten spots thanks to a finish in 6th instead of 30th. Will repost at the end of the month with exact numbers but basically anyone between 30th and 6th for May would lose 0.2 points from what is shown in the scoring table (then based on 120 mm), anyone who finished first to fifth remains as shown, and shil moves up by almost four points. If we get a bit more than 130 mm then that score could gain a bit more. 

[damianslaw]

6 hours ago, Don said:

Chances of a sub 10C final figure must be gone now?

Not necessarily, might see a marked downward adjustment as seen in April. If we see a 0.1 degree rise rest of month we will finish on 10.3 degrees, would need a 0.4 adjustment, not out of the question. 

[The PIT]

Sunny Sheffield up to 9.3C -2.2C below average, Rainfall 129.1mm 216.6% of the monthly average.

Latest local forecast would have us ending on 10.1C CET is normally higher than what we get so unlikely to be a sub 10C.

[Summer Sun]

9.7c to the 26th

1.3c below the 61 to 90 average
1.8c below the 81 to 10 average

___________________________

Current high this month 9.7c on the 22nd, 25th & 26th
Current low this month 6.6c on the 1st