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

[Midlands Ice Age]

23 hours ago, Midlands Ice Age said:

Blooming eck...

I see that the first day has seen nearly half my rainfall figure fallen!!  

MIA

I was conned by SS!!

[Roger J Smith]

April CET extremes and 1981-2010 averages

DATE ___ MAX yr _________ MIN yr ___________ CET _____ CET (cum to date)

01 Apr ... 13.3 (1995) ........ -0.2 (1917) __________ 8.3 _______ 8.3
02 Apr ... 13.9 (1835) ........ -0.5 (1917) __________ 8.1 _______ 8.2

03 Apr ... 15.0 (1926,1946) .... -0.5 (1799) _______ 7.4 _______ 7.9
04 Apr ... 15.6 (1946)......... 1.0 (1809&1830) _____ 7.1 _______ 7.7
05 Apr ... 13.3 (1857) ......... 0.4 (1911) __________ 7.1 _______ 7.6

06 Apr ... 15.1 (2011) ......... 0.8 (1911) __________ 7.5 _______ 7.6
07 Apr ... 14.7 (1859) ......... 1.0 (1839) __________ 7.3 _______ 7.5
08 Apr ... 12.5 (1798) ......... 2.4 (1780) __________ 7.2 _______ 7.5
09 Apr ... 13.7 (2017) ......... 1.4 (1812) __________ 7.5 _______ 7.5 __ max was 13.5 (1778)
10 Apr ... 13.5 (1928) ......... 0.5 (1837) __________ 8.2 _______ 7.6

11 Apr ... 16.0 (1869) ......... 1.3 (1978) __________ 8.0 _______ 7.6

12 Apr ... 14.4 (1939) ......... 1.1 (1879) __________ 7.8 _______ 7.6
13 Apr ... 14.6 (1792) ......... 1.1 (1816) __________ 7.5 _______ 7.6
14 Apr ... 16.1 (1869) ......... 0.5 (1966) __________ 8.0 _______ 7.7
15 Apr ... 16.3 (1945) ......... 1.4 (1966) __________ 8.3 _______ 7.7

16 Apr ... 17.0 (1945) ......... 2.0 (1892) __________ 8.5 _______ 7.7
17 Apr ... 14.9 (1865) ......... 2.1 (1793&1812) _____ 8.4 _______ 7.8
18 Apr ... 14.5 (1945) ......... 1.7 (1807) __________ 8.1 _______ 7.8
19 Apr ... 15.4 (1870) ......... -0.2 (1772) __________8.1 _______ 7.8
20 Apr ... 16.6 (1893) ......... 2.3 (1849) __________ 8.4 _______ 7.8

21 Apr ... 16.4 (1893) ......... 2.4 (1936) __________ 9.2 _______ 7.9
22 Apr ... 15.4 (2011) ......... 3.4 (1778) __________ 9.4 _______ 8.0
23 Apr ... 15.9 (1874) ......... 2.6 (1908) __________ 9.7 _______ 8.1
24 Apr ... 15.3 (2007) ......... 0.5 (1908) __________ 9.7 _______ 8.1
25 Apr ... 15.9 (1821) ......... 1.8 (1908) _________ 10.1 _______ 8.2 __ note: cold in 2017 (4.5)

26 Apr ... 16.1 (1928) ......... 3.3 (1981) _________ 10.1 _______ 8.3
27 Apr ... 16.5 (1866) ......... 2.7 (1919) _________ 10.1 _______ 8.3
28 Apr ... 16.9 (1775) ......... 3.0 (1826) __________ 9.9 _______ 8.4
29 Apr ... 19.7 (1775) ......... 0.7 (1856) __________ 9.9 _______ 8.4
30 Apr ... 17.4 (1775) ......... 2.6 (1945) _________ 10.5 _______ 8.5

Note: only 12 days between record high (18th) and low (30th) in 1945.

[Summer Sun]

5.3 to the 2nd

1.5 below the 61 to 90 average

I'll add the 81 to 90 data when it updates to the 3rd shortly

[Summer Sun]

21 minutes ago, Summer Sun said:

5.3 to the 2nd

1.5 below the 61 to 90 average

I'll add the 81 to 90 data when it updates to the 3rd shortly

 

Got a bit of time so I'll put it in now

5.3 to the 2nd

1.5 below the 61 to 90 average

2.9 below the 81 to 10 average

[snowray]

Big jump on the cards tomorrow, we had mins of 9-10c widely and highs today are 12-14c, 15c has been recoded in the NW.

7c-7.4c looks likely.

Edited April 3, 2018 by snowray

[Midlands Ice Age]

6 hours ago, Roger J Smith said:

April CET extremes and 1981-2010 averages

DATE ___ MAX yr _________ MIN yr ___________ CET _____ CET (cum to date)

01 Apr ... 13.3 (1995) ........ -0.2 (1917) __________ 8.3 _______ 8.3
02 Apr ... 13.9 (1835) ........ -0.5 (1917) __________ 8.1 _______ 8.2

03 Apr ... 15.0 (1926,1946) .... -0.5 (1799) _______ 7.4 _______ 7.9
04 Apr ... 15.6 (1946)......... 1.0 (1809&1830) _____ 7.1 _______ 7.7
05 Apr ... 13.3 (1857) ......... 0.4 (1911) __________ 7.1 _______ 7.6

06 Apr ... 15.1 (2011) ......... 0.8 (1911) __________ 7.5 _______ 7.6
07 Apr ... 14.7 (1859) ......... 1.0 (1839) __________ 7.3 _______ 7.5
08 Apr ... 12.5 (1798) ......... 2.4 (1780) __________ 7.2 _______ 7.5
09 Apr ... 13.7 (2017) ......... 1.4 (1812) __________ 7.5 _______ 7.5 __ max was 13.5 (1778)
10 Apr ... 13.5 (1928) ......... 0.5 (1837) __________ 8.2 _______ 7.6

11 Apr ... 16.0 (1869) ......... 1.3 (1978) __________ 8.0 _______ 7.6

12 Apr ... 14.4 (1939) ......... 1.1 (1879) __________ 7.8 _______ 7.6
13 Apr ... 14.6 (1792) ......... 1.1 (1816) __________ 7.5 _______ 7.6
14 Apr ... 16.1 (1869) ......... 0.5 (1966) __________ 8.0 _______ 7.7
15 Apr ... 16.3 (1945) ......... 1.4 (1966) __________ 8.3 _______ 7.7

16 Apr ... 17.0 (1945) ......... 2.0 (1892) __________ 8.5 _______ 7.7
17 Apr ... 14.9 (1865) ......... 2.1 (1793&1812) _____ 8.4 _______ 7.8
18 Apr ... 14.5 (1945) ......... 1.7 (1807) __________ 8.1 _______ 7.8
19 Apr ... 15.4 (1870) ......... -0.2 (1772) __________8.1 _______ 7.8
20 Apr ... 16.6 (1893) ......... 2.3 (1849) __________ 8.4 _______ 7.8

21 Apr ... 16.4 (1893) ......... 2.4 (1936) __________ 9.2 _______ 7.9
22 Apr ... 15.4 (2011) ......... 3.4 (1778) __________ 9.4 _______ 8.0
23 Apr ... 15.9 (1874) ......... 2.6 (1908) __________ 9.7 _______ 8.1
24 Apr ... 15.3 (2007) ......... 0.5 (1908) __________ 9.7 _______ 8.1
25 Apr ... 15.9 (1821) ......... 1.8 (1908) _________ 10.1 _______ 8.2 __ note: cold in 2017 (4.5)

26 Apr ... 16.1 (1928) ......... 3.3 (1981) _________ 10.1 _______ 8.3
27 Apr ... 16.5 (1866) ......... 2.7 (1919) _________ 10.1 _______ 8.3
28 Apr ... 16.9 (1775) ......... 3.0 (1826) __________ 9.9 _______ 8.4
29 Apr ... 19.7 (1775) ......... 0.7 (1856) __________ 9.9 _______ 8.4
30 Apr ... 17.4 (1775) ......... 2.6 (1945) _________ 10.5 _______ 8.5

Note: only 12 days between record high (18th) and low (30th) in 1945.

Roger 

Thanks for the above..

I find it interesting that although the Daily CET shows a daily general increase throughout the month, that the average figure flattens out and even drops after quite a high start, only to start rising at the end.

This factor explains why the calculation is not just a straight line effect (as assumed by quite a few reporters), and also explains why there seems to be no reliable /obvious way of assuming the average figure at the end of a particular day.

MIA

[Roger J Smith]

That mild start and colder turn around 4th-5th is a bit unusual, even as these 30-year means often do show some variability from a longer-period curve that "follows the sun." 

I looked at the data for 1981-2010 and the years which contribute the most to this start of April oscillation would be these in the following table where daily CET values are shown for 1st to 7th). They are listed in the order of greatest differential (1-3) to (4-7) for any days which correlates with the last entry, change in mean temp from 1-3 to 4-7. To get into the list, at least one day out of 1-3 has to be warmer than any day in the period 4-7. Any year that has a colder mean for 4-7 than 1-3 is in this list (out of the 30 available 1981-2010) except 1997 (a cold 4th otherwise all seven days mild, max on 6th) and 1998 which was fairly flat-lined from 1st to 6th and dipped slightly on the 7th and 2009 which had a warmer 7th and no particularly cold days although the mean dropped slightly. The years most opposite to this unusual trend were 1982 (which became very warm), 1984 (which started quite cold), 1993 and 2010 (both fairly average but warming faster than long-term trend). Cases shown in the table such as 1988, 1995, 1999 and 2007 were weak examples and 1981, 1994 which showed the effect in a rather subdued trend curve. Any years not in the list or mentioned in the discussion (such as 1983 etc) were fairly average and saw a general increase as one might expect from the solar (main) driver of these trends. It can be inferred from all of these facts that the unusual trend curve began around 1985 and lasted to about 2008. As shown later, it has not been a factor in years after the 30-year normal period ended in 2010.

 

YEAR ___ 01 _ 02 _ 03 ____ 04 __ 05 __ 06 __ 07 ___ gr diff ___ avg temps ___ change

_2008 __10.0__9.9_10.9___ 10.3 _ 6.6 _ 1.7 _ 4.0 ____ 9.2 ____ 10.3 __ 5.7 ___ --4.6

_1990 __11.0__9.9_ 4.7 ____ 2.4 _ 3.0 _ 4.3 _ 6.1 ____ 8.6 _____ 8.5 __ 4.0 ___ --4.5

_1989 __10.0__6.6_ 4.4 ____ 2.9 _ 2.4 _ 4.1 _ 6.1 ____ 7.6 _____ 7.0 __ 3.9 ___ --3.1

_2006 __ 9.9 __8.6_ 7.7 ____ 4.4 _ 3.2 _ 5.9 _ 6.5 ____ 6.7 _____ 8.7 __ 5.0 ___ --3.7

_2002 __11.3_10.0_13.4 ___ 11.0 _ 9.9 _ 8.2 _ 7.2 ____6.2 ____ 11.6 __ 9.1 ___ --2.5

_2004 __11.4_11.7_ 9.4 ____ 8.9 _ 7.9 _ 6.3 _ 6.8 ____ 5.4 ____ 10.8 __ 7.5 ___ --3.3

_2005 __10.4_12.3_10.5 ____9.5 _ 7.3 _ 9.3 _ 7.1 ____ 5.2 ____ 11.1 __ 8.3 ___ --2.8

_2000 __ 5.3 _ 8.2 _ 4.5 ____ 3.3 _ 5.1 _ 4.8 _ 6.3 ____ 4.9 _____ 6.0 __ 4.8 ___ --1.2 (cold to colder)

_1985 __10.6_10.9_12.4____ 9.6 _10.0_ 9.1 _ 8.1 ____ 4.3 ____ 11.3 __ 9.2 ___ --2.1

_2001 __11.2_11.4 _ 8.4 ____ 6.9 _ 7.1 _ 9.0 _ 6.9 ____ 4.3 ____ 10.3 __ 7.5 ___ --2.8

_1991 __ 9.0 _ 9.7 _ 7.3 ____ 7.1 _ 7.0 _ 5.6 _ 8.2 ____ 4.1 _____ 8.7 __ 7.0 ___ --1.7

_1986 __ 5.8 _ 3.7 _ 4.1 ____ 4.6 _ 4.0 _ 3.4 _ 1.8 ____ 4.0 _____ 4.5 __ 3.5 ___ --1.0 (cold to colder)

_1999 __13.1_11.6_ 9.0 ____12.3_12.8_12.7_ 9.4 ____ 3.7 _____11.2 _11.7 ___ +0.5 (weak case)

_1995 __13.3_11.0_ 9.9 ____ 9.8_10.2 _12.8_11.8 ____ 3.5 _____11.4 _11.2 ___ --0.2 (weak case)

_2007 ___9.4__9.4_ 6.5 ____ 6.3 _ 8.7 _ 9.3 _ 8.5 ____ 3.1 _____ 8.4 __ 8.2 ___ --0.2 (weak case)

_1988 ___5.8__8.9_ 8.4 ____ 7.5 _ 5.9 _ 7.0 _ 7.9 ____ 3.0 _____ 7.7 __ 7.1 ___ --0.6 (weak case)

_1981 ___8.0__8.4_ 7.7 ____ 5.6 _ 6.6 _ 6.8 _ 7.1 ____ 2.8 _____ 8.0 __ 6.5 ___ --1.5 (effect subdued)

_1994 ___7.1__4.8_ 5.6 ____ 5.2 _ 5.2 _ 6.3 _ 5.9 ____ 1.9 _____ 5.8 __ 5.6 ___ --0.2 (effect subdued)

 

Has the effect continued since 2010? These are the daily means of the seven years since the normal period ended.

_2011 __ 12.8_13.3_ 8.8 ____ 7.9_11.6_15.1_12.0 ____ ---- _____11.6__11.7 ___ +0.1

_2012 ___5.5__7.1_ 8.3 ____ 4.2 _ 5.5 _ 3.8 _ 7.9 ____ 4.5 _____ 7.0 __ 5.4 ___ --1.6

_2013 ___1.9__2.7_ 2.7 ____ 2.8 _ 4.0 _ 3.8 _ 3.4 ____ ---- _____ 2.4 __ 3.5 ___ +1.1

_2014 __11.1_11.3_10.6 ____10.9_10.5_12.7_11.6____ ---- _____11.0__11.4 ___ +0.4

_2015 ___6.2__7.2_ 8.4 ____ 8.5 _ 9.0 _ 8.1 _ 8.7 ____ ---- ______7.3 __ 8.6 ___ +1.3

_2016 ___5.5__9.9_10.0 ___10.3 _ 9.0 _ 7.5 _ 7.3 ____ ---- ______8.5 __ 8.5 ____ 0.0

_2017 __11.1__9.8_ 9.4 ____10.7 _ 7.9 _ 7.9 _ 8.0 ____ 3.2 _____10.1 __ 8.8 ___ --1.3

_mean __ 7.7__8.6__8.2 ____ 7.9 _ 8.3 _ 8.4 _ 8.4 ____ ---- _____ 8.3 __ 8.3 ___ 0.0

 

From the above it can be seen that the anomalous effect is almost extinguished from the data after 2010, although there is a faint trace of it evident from the slightly higher mean for the 2nd than other dates. The effect seemed to be at its peak in the 1990s and 2000s decades. 

The most significant fact uncovered in this data analysis is that 12 cases judged to be strongly supporting the unusual trend were balanced against only three that were unusually positive (exaggerated "normal" trend). Many other years had just weak trends in this period, but with 13/30 strongly pushing down (they averaged a decrease of 2.7 deg) this explains the rather salient anomaly mentioned in the previous post. 

 

[Roger J Smith]

It's worth noting that this anomaly of colder trends in early April does not appear in the full set of daily data at all, those averages follow the expected solar-driven trend curve.

I produced some daily means for the Dalton period using 1795-1824 and there you can find a somewhat similar against-the-warming-trend period from 9th to 12th of April.

There is probably no "explanation" of these anomalies, they can be expected to show up somewhere in any given 30-year interval because of random variability and the relatively small sample size of 30 years. They almost disappear in 240 years of data although you can find small persistent "second order variations" of less than half a degree such as the relative maximum around 21st to 24th of January. 

On a quick inspection of the 1981-2010 period, some other anomalies would include these (in calendar order) ...

7-8 Jan are colder and 19-21 Jan are warmer than surrounding dates.

4-6 Feb are warmer and 14-21 Feb are colder.

12-13 Mar show a downturn against the steady rising trend.

4-7 April as noted are also a colder interval. 

2-4 May is a third cold spring period and 23-24 May unusually warm.

5-6 Aug are relatively warm as are 25-26 Nov and 3-5 Dec; 20 Dec is noticeably colder than dates either side.

Edited April 3, 2018 by Roger J Smith

[More Runs Needed]

72.6mm and 8.3c am I too late 

[Roger J Smith]

not too late, just starting to assemble tables of entries to absolute deadline of midnight this evening (4th 0001h) _ precip contest closes 4th at 0300h as I give 3h grace periods for late entries in that one. 

[Roger J Smith]

Tables of entries are posted here:

https://www.netweather.tv/forum/topic/75427-cet-competition-the-scores-ongoing/?page=8

There were 62 temperature forecasts, median was 8.4 C.

and 47 precip forecasts, median 79.0 mm. 

Good luck !

[Summer Sun]

6.4 to the 3rd

0.1 below the 61 to 90 average

1.5 below the 81 to 10 average

______________________________________

Current high this month 6.4 to the 3rd

[snowray]

That's a lot lower than what I worked out, must be doing it wrong. Think I'll just leave the calculations to the professionals from now on!

[NorthYorksWeather]

5.9c here to the 3rd, 1.7c below the 1981-2010 average.

[Summer Sun]

7.0 to the 4th

0.6 above the 61 to 90 average

0.7 below the 81 to 10 average

______________________________________

Current high this month 7.0 to the 4th

[Don]

1 hour ago, Summer Sun said:

7.0 to the 4th

0.6 above the 61 to 90 average

0.7 below the 81 to 10 average

______________________________________

Current high this month 7.0 to the 4th

Up we go!

[The PIT]

Sunny Sheffield at 5.4C -1.2C below normal. Rainfall 40.1mm 63.4% of normal.

[Summer Sun]

6.8 to the 5th

0.4 above the 61 to 90 average

0.8 below the 81 to 10 average

______________________________________

Current high this month 7.0 to the 4th

[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)

7.2C to the 6th... -0.4  (9.6: +2.1)
7.6C to the 7th... +0.0  (9.5: +2.2)
7.7C to the 8th... +0.2  (9.0: +1.8)
7.9C to the 9th... +0.4  (9.5: +2.0)
8.2C to the 10th... +0.6  (10.6: +2.4)
8.1C to the 11th... +0.5  (7.5: -0.5)
8.1C to the 12th... +0.5  (7.6: -0.2)
8.0C to the 13th... +0.3  (6.4: -1.1)
7.9C to the 14th... +0.3  (7.7: -0.3)
7.9C to the 15th... +0.2  (6.8: -1.5)

Not much consistency in the CET values so far. A cool start, followed by some mild days. A cool day yesterday, mild for the next few days before turning cool again. Main results is we should be a little above the 81-10 rolling average by the end of the weekend.

[Summer Sun]

7.2 to the 6th

0.8 above the 61 to 90 average

0.4 below the 81 to 10 average

______________________________________

Current high this month 7.2 to the 6th

[The PIT]

Sunny Sheffield up to 5.8C -0.9C below normal. No change in rainfall. GFS showing a general mild outlook cool days offset by mild nights should be above normal by the end of next week at least.

[Summer Sun]

7.6 to the 7th

1.1 above the 61 to 90 average

0.1 below the 81 to 10 average

______________________________________

Current high this month 7.6 to the 7th

[The PIT]

Sunny Sheffield up to 6.1C -0.6C below normal, Rainfall 40.6mm 64.2% of average

[Roger J Smith]

^^ I assume that's 64% of the total monthly average so around 250% of normal for the portion of the month so far.

[Summer Sun]

7.8 to the 8th

1.3 above the 61 to 90 average

0.3 above the 81 to 10 average

______________________________________

Current high this month 7.8 to the 8th