Ensemble Checks

[summer blizzard]

I have opened this thread in order to compare ensemble temperature profiles so that we can see at what range is there a small enougth agreement for us to be able to develop a reasonable temperature expectation.

As Thundery Wintry Showers has shown with his GFS12z model comparisons, while the GFS has ussually picked out the positioning of a area of low or high pressure at 144 hours out, it often struggles with the pressure value of the area of low or high pressure. One of the things which we will find out from this thread is what the impact of the pressure value on temperature is.

I will start at the 5th May as that is when the temperature profiles diverge according to the GFS12z ensembles.

5th May - 7C to 9C - 2C scatter

6th May - 4C to 8C - 4C scatter

7th May - 0C to 8C - 8C scatter

8th May - -1C to 5C - 6C scatter

9th May - 0C to 6C - 6C scatter

10th May - 2C to 8C - 6C scatter

11th May - 1C to 8C - 7C scatter

12th May - 2C to 10C - 8C scatter

13th May - 4C to 8C - 4C scatter

14th May - 2C to 11C - 9C scatter

15th May - 3C to 14C - 11C scatter

16th May - 0C to 11C - 11C scatter

17th May - 0C to 10C - 10C scatter

As you can see from that, there is reasonable agreement on temperature profiles for the next eight days however after that, scatter increases dramatically.

In regards to the 13th May, there is a 4C agreement, while i expect agreement to lessen over the next few days, i believe that the final value will be between 4C and 8C.

I will try update tommorow.

[summer blizzard]

Here is my GFS6z ensemble analysis...

10th May - 0C - 5C - 5C scatter - increased agreement - 2C - 5C likely

11th May - 2C - 6C - 4C scatter - increased agreement - 2C - 6C likley

12th May - 4C - 10C - 6C scatter - increased agreement - 4C - 10C likley

13th May - 4C - 11C - 7C scatter - decreased agreement - 4C - 8C likley

14th May - 3C - 12C - 9C scatter - same agreement - 3C - 11C likely

15th May - -2C - 12C - 14C scatter - decreased agreement - 3C - 12C likely

16th May - -2C - 12C - 14C scatter - decreased agreement - 0C - 11C likley

17th May - -4C - 12C - 16C scatter - decreased agreement - 0C - 10C likely

18th May - -2C - 10C - 12C scatter

19th May - 2C - 13C - 11C scatter

20th May - 1C - 10C - 9C scatter

21st May - 0C - 14C - 14C scatter

In conclusion, there is horrible agreement after the 14th May due to one rogue run increasing ensemble scatter.

I have illustrated the ensembles to show the most likely outcome.

[summer blizzard]

Here is my GFS0z ensemble analysis...

10th May - 2C - 8C - 5C scatter - decreased agreement - 2C - 5C likely

11th May - 2C - 7C - 5C scatter - decreased agreement - 2C - 6C likley

12th May - 3C - 8C - 5C scatter - increased agreement - 4C - 8C likley

13th May - 4C - 12C - 8C scatter - decreased agreement - 4C - 8C likley

14th May - 4C - 9C - 5C scatter - increased agreement - 4C - 9C likely

15th May - 3C - 10C - 7C scatter - increased agreement - 3C - 10C likely

16th May - -3C - 11C - 14C scatter - same agreement - 0C - 11C likley

17th May - -3C - 12C - 15C scatter - increased agreement - 0C - 10C likely

18th May - 0C - 9C - 9C scatter - increased agreement - 0C - 9C likely

19th May - 0C - 9C - 9C scatter - increased agreement - 2C - 9C likely

20th May - 2C - 10C - 8C scatter - increased agreement - 2C - 10C likely

21st May - 2C - 11C - 9C scatter - increased agreement - 2C - 11C likely

22nd May - 1C - 11C - 10C scatter

In conclusion, there is fairly good agreement throughout the run aside from the 16th and 17th May, which is causing problems for the models.

I have illustrated the ensembles to show the most likely outcome.

[summer blizzard]

Here is my GFS6z ensemble analysis...

10th May - 2C - 0C scatter - increased agreement - 2C likely

11th May - 2C - 5C - 3C scatter - increased agreement - 2C - 5C likley

12th May - 5C - 11C - 6C scatter - decreased agreement - 5C - 8C likley

13th May - 7C - 12C - 5C scatter - increased agreement - 7C - 8C likley

14th May - 6C - 14C - 8C scatter - decreased agreement - 6C - 9C likely

15th May - 4C - 14C - 10C scatter - decreased agreement - 4C - 10C likely

16th May - 3C - 10C - 7C scatter - increased agreement - 3C - 10C likley

17th May - -1C - 10C - 11C scatter - increased agreement - 0C - 10C likely

18th May - 0C - 11C - 11C scatter - decreased agreement - 0C - 9C likely

19th May - -1C - 9C - 10C scatter - increased agreement - 2C - 9C likely

20th May - 2C - 7C - 5C scatter - increased agreement - 2C - 7C likely

21st May - -2C - 8C - 10C scatter - decreased agreement - 2C - 8C likely

22nd May - -2C - 12C - 14C scatter - decreased agreement - 1C - 11C likely

In conclusion, there is average agreement on this run however agreement has increased around the 15th May, which is causing problems for the models, the outlook looks above average. This run has picked out the 20th as a potential average spell with good agreement.

I have illustrated the ensembles to show the most likely outcome.

[summer blizzard]

Here is my GFS6z ensemble analysis...

11th May - 7C - 0C scatter - increased agreement - 7C likley

12th May - 8C - 0C scatter - increased agreement - 8C likley

13th May - 8C - 10C - 2C scatter - increased agreement - 8C likley

14th May - 4C - 8C - 4C scatter - increased agreement - 6C - 8C likely

15th May - 5C - 8C - 3C scatter - increased agreement - 5C - 8C likely

16th May - 5C - 11C - 6C scatter - increased agreement - 5C - 10C likley

17th May - 6C - 10C - 4C scatter - increased agreement - 6C - 10C likely

18th May - 3C - 10C - 7C scatter - increased agreement - 3C - 9C likely

19th May - -1C - 9C - 10C scatter - same agreement - 2C - 9C likely

20th May - -3C - 9C - 12C scatter - decreased agreement - 2C - 7C likely

21st May - -1C - 9C - 10C scatter - same agreement - 2C - 8C likely

22nd May - -3C - 7C - 10C scatter - increased agreement - 1C - 7C likely

23rd May - -1C - 11C - 12C scatter

24th May - 1C - 11C - 10C scatter

25th May - 0C - 9C - 9C scatter

In conclusion, there is good agreement on this run until the 19th May, temperatures look like they could become more average around the 20th.

I have illustrated the ensembles to show the most likely outcome.

[summer blizzard]

Here is my GFS12z ensemble analysis...

22nd May - 5C - 0C scatter - increased agreement - 5C likely

23rd May - 0C - -1C - 1C scatter - increased agreement - 0C - -1C likely

24th May - 1C - 0C scatter - increased agreement - 1C likely

25th May - 1C - 5C - 4C scatter - increased agreement - 1C - 5C likely

26th May - 2C - 8C - 6C scatter

27th May - -2C - 10C - 12C scatter

28th May - -3C - 7C - 10C scatter

29th May - -1C - 7C - 8C scatter

30th May - -2C - 6C - 8C scatter

31st May - -2C - 6C - 8C scatter

1st June - 2C - 11C - 9C scatter

2nd June - 3C - 10C - 7C scatter

3rd June - 1C - 13C - 12C scatter

4th June - 1C - 15C - 14C scatter

5th June - 1C - 15C - 0C scatter

6th June - 0C - 16C - 16C scatter

In conclusion, decent agreement for the next ten days aside from this weekend with signs of more average temperatures next week with maximum temperatures close to 20C before the possibility of a heatwave arriving with June.