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

[Derecho]

4 hours ago, The PIT said:

Sunny Sheffield at 16.9C +4.5C above normal. Rainfall 3.4mm 4.4% of the average rainfall.

Huge contrast  from last month already and plenty of warm weather on the way by mid month it will be still hugely above average. Might be worth thinking about a record warm month.

The EC 00z this morning is pretty impressive to say the least. If that came off we would have a CET of ~17.6C by the 16th. If we got to that point then records are definitely within reach.

[Roger J Smith]

On 07/06/2021 at 03:29, summer blizzard said:

Well let's think logically. The record is at 18C so how many second halves have been above that.

The record warm June (18.2) was not among them, the halves were 18.6 and 17.8.

In fact there were only three Junes with second halves of 18.0 or higher, those being

1976 __ 18.4

1826 __ 18.1

1941 __ 18.0

and the rest of the top 12 (17.1 and above) in this measure would be as follows: 

17.9 ___ (none)

17.8 ___ 1817, 1846, 2005 (t4)

17.7 ___ (none)

17.6 __ 1857, 1936 (t7)

17.5 __ 1772 (8)

17.4 __ 1798, 1878, 1935 (t9)

17.3 __ (none)

17.2 __ 2017 (12)

17.1 __ (none)

(17.0 ... 1794 (13))

_________________________________

They never had a very warm second half of June from 1879 to 1934, the max in that 56-year stretch was 16.5 C. 

From 1942 to 1975 the warmest was only 16.9 (1960). 

_________________________________

So not very many even above 17 let alone 18. 

Last year was 16.8 and 2018 was 16.6 in case you were wondering. 

Has to be said that the current GFS output is going in the other direction for the second half, from about Tuesday 15th on the indicated trend is down, down, down with a mean of only about 13-14 C. 

Maybe the list to consult is the one I put up around the first of June, drops from first to second half of June, there are several on there starting from the mid-17s and taking various kinds of falls. By the way, the warmest first half of June averages (also above 17.0) are

1846 __ 18.6

1822 __ 17.8

1858 __ 17.6

1940 __ 17.5

1775 __ 17.2

1970 __ 17.1 

All of those were cooler by end of June. 

 

Edited June 8, 2021 by Roger J Smith

[Derecho]

22 minutes ago, Roger J Smith said:

The record warm June (18.2) was not among them, the halves were 18.6 and 17.8.

In fact there were only three Junes with second halves of 18.0 or higher, those being

1976 __ 18.4

1826 __ 18.1

1941 __ 18.0

 

Yup 1976 top as I would expect, had some cool days mid-month though. The CET for the last 8 days was 21.5C

Interesting to see 1941 up there given how cool April and May were, same for 1817 which had a really cool May.

[summer blizzard]

Well that is interesting indeed. 

[The PIT]

Sunny Sheffield still at 16.9C +4.3C above normal. Rainfall unchanged at 3.4mm 4.4% of the monthly average.

[Summer Sun]

16.2c to the 7th

2.9c above the 61 to 90 average
2.6c above the 81 to 10 average

___________________________

Current high this month 17.7c on the 2nd
Current low this month 16.1c on the 5th

[BornFromTheVoid]

Latest projection for June

 

The chances of finishing:
Close to average (14.2C to 15.2C) is to 28.1% (2 days ago was 38.6%)
Above average (>15.2C) is to 71.5% (2 days ago was 56.2%)
Below average (<14.2C) is  to 0.4% (2 days ago was 5.2%)

The period of the 8th to the 13th is forecast to average 17.7C, 3.6C above the 91-20 average.

[Man With Beard]

On 07/06/2021 at 11:37, Quicksilver1989 said:

The EC 00z this morning is pretty impressive to say the least. If that came off we would have a CET of ~17.6C by the 16th. If we got to that point then records are definitely within reach.

It's a mammoth ask but this morning there were probably 20% of ECM ensemble members capable of getting the CET close to 18C by 22nd June.

[Derecho]

38 minutes ago, Man Without Beard said:

It's a mammoth ask but this morning there were probably 20% of ECM ensemble members capable of getting the CET close to 18C by 22nd June.

Yeah it is a big ask indeed, some of the EC members in late June are crazy hot. However most are slightly above or near normal. GFS ensembles are still much cooler.

One of the EC 12z ensemble members last night had a 24 hour mean > 27C on June 20th!!!!

Edited June 8, 2021 by Quicksilver1989

[Earthshine]

I thought my guess of 17.2°C was pretty ridiculous at the time but it seems it could well be within the outer realms of possibility?

[BornFromTheVoid]

48 minutes ago, Earthshine said:

I thought my guess of 17.2°C was pretty ridiculous at the time but it seems it could well be within the outer realms of possibility?

From the projections earlier, about a 12% chance of being within 0.5C of 17.2C before corrections.

[Earthshine]

1 hour ago, BornFromTheVoid said:

From the projections earlier, about a 12% chance of being within 0.5C of 17.2C before corrections.

Interesting, thanks for that!

[Derecho]

A nod towards the GFS on the latest EC OP with cool air coming from the NW in the middle of the next week, that would scupper any unlikely contest with 1846...

[North-Easterly Blast]

The chance of a notably warm first half of June must be very likely by now.  The CET by the 15th could well get close to 17*C, and at the very least is likely to be above 16.5.  I cannot think of when the last occasion was that we had such a warm first half of June.  If the CET is that high by mid-month the chance of a notably high overall June CET is there; granted there have in the past been second halves of June that were cooler than the first half although this happens less often than the other way round.  Even if the second half of this month does not see a continuation of the warm first half, a final CET finish below the 15s at this point looks very unlikely, and it is already looking like the warmest June since 1976 could well be underway.  After a cool April and May, the chances of getting a third below average month seemed unlikely at least by the last 30 odd years' standards, and after the coolest April / May pair since 1941 we could well be looking at the first significantly above average month of 2021. 

[DAVID SNOW]

28 minutes ago, North-Easterly Blast said:

The chance of a notably warm first half of June must be very likely by now.  The CET by the 15th could well get close to 17*C, and at the very least is likely to be above 16.5.  I cannot think of when the last occasion was that we had such a warm first half of June.  If the CET is that high by mid-month the chance of a notably high overall June CET is there; granted there have in the past been second halves of June that were cooler than the first half although this happens less often than the other way round.  Even if the second half of this month does not see a continuation of the warm first half, a final CET finish below the 15s at this point looks very unlikely, and it is already looking like the warmest June since 1976 could well be underway.  After a cool April and May, the chances of getting a third below average month seemed unlikely at least by the last 30 odd years' standards, and after the coolest April / May pair since 1941 we could well be looking at the first significantly above average month of 2021. 

First half yes i would agree, as for the second half, perhaps not, nothing showing that leads to anything being underway.

[Roger J Smith]

Warmth in the first half of June does not have a very good track record for anchoring warm summers in general. Same thing applies in North America, a bit of a hit or miss correlation of warmth in early June with the rest of summer. Warmth in second half of June seems to be a more reliable indicator. 

June 1925 and late May, early June 1895 severe heat waves in eastern North America led to rather cool summers and a few late summer (mid-September hot spells). June 1919 and 1949 remained very warm from start to finish and those became hot summers in general. 1984 was a more recent example of an early June heat wave that failed to sustain itself into the summer. 

The British climate seems even more skewed towards bad outcomes from early June warmth as I showed with the list of warm first halves, and while summer 1846 was not entirely a cool spell after June ended, it never returned to that level. 

The six warmest first halves of June all turned cooler, so I had a look to see what rank was the first one to turn warmer. (to be fair, it is easier for a very warm first half to turn cooler than at random) ... it turns out that of the ten years that followed the top six (with first halves 16.0 to 16.9), eight of those also turned cooler. The warmest first half to turn warmer still was t-12th place 1826 (16.5 to 17.3) and then also t-14th place 1798 which increased from 16.3 to a finish of 16.9. Beyond the 20th place 2006 which only dropped by 0.1, you have to go into the 15s to find first halves that did not turn cooler (only seven of the years in my original list of cooler second halves started from 15.0-15.9 and there were twice as many others that got warmer). 

Below the top six, the next fourteen (rest of top 20) were 1933 (16.8 to 15.6), 1950 (16.8 to 16.2), 1818 (16.7 to 16.4), 1982 (16.7 to 15.6), 1896 (16.6 to 16.2), 2004 (16.6 to 15.3), 1826 (16.5 to 17.3), 1842 (16.5 to 15.6), 1798 (16.3 to 16.9), 1835 (16.3 to 15.0), 1966 (16.2 to 15.4), 1925 (16.1 to 15.0), 1963 (16.1 to 14.9), 2006 (16.0 to 15.9) ... so in total, 18 of the 20 went down at least slightly. 

I suppose you could excuse 1846 which remained warmest June anyway, and 2006 was a very minor decrease; so were 1818 and 1896 in the list above.

We'll have to see if 2021 bucks this trend which seems pretty robust. 

[summer blizzard]

While I’m not suggesting we’ll fail here it’s also worth remembering May 08. The first half ran at record pace (something like 5C above average) but then dropped back to a bog standard warm month.

[BlueHedgehog074]

On 31/05/2021 at 08:11, saintkip said:

Not very secret you’ve just told everyone 

Nope, not very secret at all was it?

It’ll be interesting to see whether the warm to very warm conditions can be maintained throughout this month. It’s possible the second half of the month could see some kind of cool down, as what seems to be the case sometimes (although I get the sneaky feeling it’ll stay mostly warm to very warm)

[LetItSnow!]

Still thinking a much cooler second half of June is in order. Would take something pretty cold to get to my guess, but anyone who's in the low 15s I reckon could be in for a chance still. 15-17 the name of the game I feel. Of course it could go into a Jun. 1997/2004/2007 type pattern

[The PIT]

Sunny Sheffield down to 16.8C +4.2C above normal. Rainfall unchanged.

[Summer Sun]

16.1c to the 8th

2.7c above the 61 to 90 average
2.5c above the 81 to 10 average

___________________________

Current high this month 17.7c on the 2nd
Current low this month 16.1c on the 5th & 8th

[Timmytour]

On 02/06/2021 at 13:12, BornFromTheVoid said:

First projection for June

 

The chances of finishing:
Close to average (14.2C to 15.2C) is at 37.3% 
Above average (>15.2C) is at 45.8% 
Below average (<14.2C) is at 16.9% 

The period of the 2nd to the 7th is forecast to average 16.6C, 2.8C above the 91-20 average.

 

On 02/06/2021 at 17:09, Timmytour said:

I'm really surprised at that below average percentage.  Would expect to see that fall to less than 3% by the end of this week....

 

On 08/06/2021 at 12:12, BornFromTheVoid said:

Latest projection for June

 

The chances of finishing:
Close to average (14.2C to 15.2C) is to 28.1% (2 days ago was 38.6%)
Above average (>15.2C) is to 71.5% (2 days ago was 56.2%)
Below average (<14.2C) is  to 0.4% (2 days ago was 5.2%)

The period of the 8th to the 13th is forecast to average 17.7C, 3.6C above the 91-20 average.

Took a bit longer than I envisaged.....but it got there and some!

[Weather-history]

20 hours ago, DAVID SNOW said:

First half yes i would agree, as for the second half, perhaps not, nothing showing that leads to anything being underway.

Just out of interest look how much June 2007 crashed and burned after a pretty good start

CET: (Jun 1-12): 16.4°C (+2.9 degC)

E&W Rain: (Jun 1-12): 4.4mm ( 16 per cent)

E&W Sun: (Jun 1-12): 75.8hr (100 per cent)

 

Final CET: 15.1C

Final Rainfall: 144.9mm

Sunshine: 148.6hrs 

[Roger J Smith]

Looks like a good chance of ending that 13th June anomaly (no max above 30?) ... after that the current guidance looks like a gradual cooling trend to near or slightly below normal values for much of the time, could see a peak of 17.5 in the CET around Sunday-Monday then a slow slide down into the 16s. Currently not enough cold air depicted to say 15s are in play but then the model run ends on 25th. EWP looks like it would slowly accumulate towards near average outcomes, some recent days have had heavy rain events suggested but not so much in the current run. Would set the "best estimate" based on GFS guidance near 16.5, 50 mm at this point. 

[Scorcher]

23 minutes ago, Weather-history said:

Just out of interest look how much June 2007 crashed and burned after a pretty good start

CET: (Jun 1-12): 16.4°C (+2.9 degC)

E&W Rain: (Jun 1-12): 4.4mm ( 16 per cent)

E&W Sun: (Jun 1-12): 75.8hr (100 per cent)

 

Final CET: 15.1C

Final Rainfall: 144.9mm

Sunshine: 148.6hrs 

Rostherne was already on 73 hours of sun up to yesterday after only 8 days of the month- we will be well ahead of the 2007 figure after today with only 9 days of the month gone . Not sure about the overall CET zone sunshine though.