April 2016 C.E.T. forecasts

[Summer Sun]

8.3c to the 9th

1.7c above the 61 to 90 average

0.8c above the 81 to 10 average

Edited April 10, 2016 by Summer Sun

[BornFromTheVoid]

The minimum today is -0.7C (coldest since March 8th) while maxima look like reaching the mid to high 11s, so a drop to 8.0C is likely on tomorrows update.

After that, the 06z GFS has the CET at:

8.1C to the 11th (9.5: +1.5)
8.3C to the 12th (10.2: +2.4)
8.4C to the 13th (9.5: +2.0)
8.5C to the 14th (9.7: +1.7)
8.6C to the 15th (9.9: +1.6)
8.6C to the 16th (8.3: -0.2)
8.5C to the 17th (7.9: -0.5)
8.6C to the 18th (10.0: +1.9)
8.6C to the 19th (8.8: +0.7)

A lot of uncertainty over the next 10 days, as the boundary between cool northerly air and mild southerlies sits across the UK. The last few GFS runs have had the CET to the 18th vary from 7.9C to 9.4C, with this mornings GFS right in the middle.
If the CET was to match the 81-10 average after the 19th, the final value would be 9.0C before corrections.
 

[Summer Sun]

8.1c to the 10th

1.4c above the 61 to 90 average

0.5c above the 81 to 10 average

[Summer Sun]

8.2c to the 11th

1.5c above the 61 to 90 average

0.6c above the 81 to 10 average

[Summer Sun]

8.3c to the 12th

1.6c above the 61 to 90 average

0.7c above the 81 to 10 average

[The PIT]

Sunny Sheffield at 7.7C today should rise to 7.9C tomorrow. Close enough for average for the time of year.

[damianslaw]

It would be good to include the anomaly against the final CET averages as well, as it could be a bit misleading to someone who might think we are currently sitting 1.5 degree above the overall final April CET 61-90 average, when indeed we aren't that far away from it.

[Weather-history]

35 minutes ago, damianslaw said:

It would be good to include the anomaly against the final CET averages as well, as it could be a bit misleading to someone who might think we are currently sitting 1.5 degree above the overall final April CET 61-90 average, when indeed we aren't that far away from it.

Yes that average is so out of date, now. We can almost fit a 30 year average between then and now. 

[Summer Sun]

8.4c to the 13th

1.5c above the 61 to 90 average

0.8c above the 81 to 10 average

[Summer Sun]

8.5c to the 14th

1.5c above the 61 to 90 average

0.8c above the 81 to 10 average

[Roger J Smith]

If the current GFS verified, the CET would remain in the low to mid 8 range until late next week (peaking around 8.7-8.9) and would then slide down in a very cool end of April northerly regime that looks cold enough for snow showers around the 27th to end of month. Could finish in the 7s if all that actually comes to pass. If let's say we made it to 8.8 by the 20th then for 7.7 at end of month the mean would have to run 5.5 for the last ten days. That's about what the GFS is showing today.

[Summer Sun]

8.5c to the 15th

1.5c above the 61 to 90 average

0.8c above the 81 to 10 average

[DAVID SNOW]

Just going by this mornings GFS, the CET could be down to around 7.6 by the 26th

[BornFromTheVoid]

A minimum today of 2.1C, while maxima look like reaching about 8C, so a drop to 8.2 or 8.3C is likely tomorrow.

After that, the 06z GFS has the CET at:

8.0C to the 17th (4.6: -3.8)
7.9C to the 18th (6.2: -1.9)
7.9C to the 19th (7.3: -0.8)
7.9C to the 20th (7.2: -1.2)
7.9C to the 21st (8.4: -0.8)
7.9C to the 22nd (7.8: -1.6)
7.7C to the 23rd (4.7: -5.0)
7.7C to the 24th (7.5: -2.2)
7.6C to the 25th (3.8: -6.3)
 

A very cool 2nd half of the month now looking likely, with the period of the 16th to the 25th forecast to average just 6.2C. The last time we had a 2nd half of April cooler than 7C was in 1991, with 6.6C

[Roger J Smith]

COLDEST SECOND HALVES of APRIL 1772-2015

_______________________________________________

 

Rank __ Year ___ Mean CET ____ Coldest day

__ 1 __ 1808 ____ 4.5 __________ 2.5 (19th)

__ 2 __ 1838 ____ 4.9 __________ 2.4 (19th)

__ 3 __ 1782 ____ 5.4 __________  3.1 (29th)

__ 4 __ 1812 ____ 5.5 __________ 2.1 (17th)

__ 5 __ 1908 ____ 5.6 __________ 0.5 (24th) (and 1.8 25th)

__ 6 __ 1884 ____ 5.6 __________ 3.9 (23rd)

__ 7 __ 1877 ____ 5.8 __________ 4.4 (17th) (3.1 on 3 May)

__ 8 __ 1809 ____ 5.8 __________ 3.3 (18th & 19th)

__ 9 __ 1860 ____ 5.9 __________ 2.8 (21st)

__10 __ 1906 ____ 5.9 _________ 3.8 (26th)

__11__ 1772 ____ 6.0 _________ -0.2 (19th)

________________________________________________________

ties were broken by second decimals ... the coldest day not included in one of these sub 6.0 half months was 0.7 (29th of 1856). Most of the daily records from 16th to 30th are included above.

Notice that no years qualified for this list after 1908. The five coldest values since then are:

6.2 (1922 and 1981)

6.6 (1956 and 1991)

6.7 (1989)

[Weather-history]

I wonder when the last time a December was warmer than the previous and subsequent Aprils?

[BornFromTheVoid]

1 hour ago, Weather-history said:

I wonder when the last time a December was warmer than the previous and subsequent Aprils?

Don't think it's happened before. December 1934 was probably closest. It was 0.1C above April 1934 and 0.1C below April 1935.

[Summer Sun]

8.3c to the 16th

1.1c above the 61 to 90 average

0.6c above the 81 to 10 average

[The PIT]

On 13/04/2016 at 8:32 PM, damianslaw said:

It would be good to include the anomaly against the final CET averages as well, as it could be a bit misleading to someone who might think we are currently sitting 1.5 degree above the overall final April CET 61-90 average, when indeed we aren't that far away from it.

I presume this is a dig against me posting the Sheffield average. Sadly I don't have the weekly averages otherwise I would. However the difference shouldn't be that much different from the ones Summer Sun posts as I'm simply posting the difference between the CET and just being out of the CET area.

[Relativistic]

Here's another one. Only six times previously have both the March and April CETs of one year been colder than the previous December's CET.

December 1687: 6.0 ---> March 1688: 3.5, April 1688: 5.5
                1781: 5.4 ---> 1782: 4.1, 5.2
                1828: 7.4 ---> 1829: 4.3, 6.7
                1852: 7.7 ---> 1853: 3.4, 7.6
                1921: 6.5 ---> 1922: 4.6, 5.5
                1985: 6.3 ---> 1986: 4.9, 5.8

We're looking certain to extend this list this year.

[Summer Sun]

8.1c to the 17th

0.8c above the 61 to 90 average

0.3c above the 81 to 10 average

[BornFromTheVoid]

Minimum today is 4.1C while maxima look like reaching the low 11s, so we're likely to remain at 8.1C on tomorrows update.

After that, the 06z GFS has the CET at:

8.1C to the 19th (7.7: -0.4)
8.0C to the 20th (7.5: -0.9)
8.0C to the 21st (8.2: -1.0)
8.0C to the 22nd (7.9: -1.5)
7.9C to the 23rd (4.9: -4.8)
7.7C to the 24th (4.1: -5.6)
7.7C to the 25th (5.8: -4.3)
7.5C to the 26th (2.1: -8.0) [Record low: 3.3C]
7.3C to the 27th (3.3: -6.8) [Record low: 2.7C]

Some exceptionally cool conditions towards the end of the GFS this morning. Will have to keep an eye on them if they remain across several runs.
 

[reef]

Its certainly looking like the pattern of cold Aprils following strong El Ninos is set to continue. If some of the low temperatures shown on this morning's runs come to fruition then something in the high 6s isn't entirely out of the question after adjustments.

Its worth bearing in mind that if April were to finish on 7C then a May of 10.3C would give us the smallest difference between the winter and spring average temps on record (1.07C difference back in 1869).

[Roger J Smith]

19 hours ago, The PIT said:

I presume this is a dig against me posting the Sheffield average. Sadly I don't have the weekly averages otherwise I would. However the difference shouldn't be that much different from the ones Summer Sun posts as I'm simply posting the difference between the CET and just being out of the CET area.

Not about your posts, PIT, I'm pretty sure the objection is to the anomaly being posted against cumulative CET as opposed to outcome CET for end of month. I think most people who read and participate in these threads know the difference and are making their own comparisons against end of month. The value of the comparison to date (especially in a transitional month like April or October) is that you get a sense of how the current regime is compared to normal values. But it would add some value to the posts if there were two more references to end of month values for 1961-90 and 1981-2010 as well. Somebody will then object that these comparisons are apples to oranges but the only real comparison that most of us are checking is current CET vs prediction.

 

[Summer Sun]

8.1c to the 18th

0.8c above the 61 to 90 average

0.3c above the 81 to 10 average