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

[The PIT]

Sunny Sheffield down to 6.2C -0.9C below normal. Rainfall 74.3mm 117.6% of average.

[Roger J Smith]

12 hours ago, BornFromTheVoid said:

Warmth downgraded on the 06z, with the CET not reaching 10C within the his res time frame. Still a few record breaking days, but not quite the abnormal warmth shown in many recent runs.

Looking at the 18z GFS I would estimate 9.0 to 9.5 by end of month, it easily gets to 9.5 or a bit higher by 20th, but there's no further warmth from there to end of month and so it would be fighting to stay above 9.0 all the way to the finish (the average near end of the run looks like 8-10 C). If the warm spell has any downgrades then it could even stay close to 9 or fall back into the high 8's, but the warm spell does look record-breaking, don't think we'll quite push out the all-time warmest April day from 1775 but last year we did it to March 1777. 

[Summer Sun]

7.8 to the 13th

1.0 above the 61 to 90 average

0.2 above the 81 to 10 average

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Current high this month 7.8 to the 8th, 9th, 10th, 11th, 12th & 13th

[The PIT]

Sunny Sheffield still at 6.2C -1.0C below normal, Rainfall 75.2mm 119% of normal

[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)

8.1C to the 14th.... 0.4 (10.8: +2.8)
8.2C to the 15th.... 0.5 (10.3: +2.0)
8.3C to the 16th.... 0.6 (9.6: +1.1)
8.6C to the 17th.... 0.8 (12.8: +4.4)
8.9C to the 18th.... 1.1 (15.1: +7.0)  [Daily Record = 14.5C from 1945]
9.4C to the 19th.... 1.6 (17.9: +9.8) [Daily Record = 15.4C from 1870]
9.9C to the 20th.... 2.0 (18.6: +10.2) [Daily Record = 16.6C from 1893]
10.3C to the 21st... 2.4 (19.1: +9.9) [Daily Record = 16.1C from 1893]
10.4C to the 22nd... 2.5 (13.4: +4.0)
10.5C to the 23rd... 2.5 (12.3: +2.6)

The ridiculous warmth returns on this mornings run, an exceptional few days before dropping back closer to normal. Potential for setting the 2nd, 3rd and 4th warmest April days on record!

[Roger J Smith]

With that in mind, current top 14 April CET days (four tied 11th) are:

 1. 19.7 __ 29th, 1775

 2. 17.4 __ 30th, 1775

 3. 17.0 __ 16th, 1945

 4. 16.9 __ 28th, 1775

 5. 16.8 __ 30th, 1827*

 6. 16.6 __ 20th, 1893

 7. 16.5 __ 27th, 1866

 8. 16.3 __ 29th, 1828*

 8. 16.3 __ 15th, 1945

10. 16.2 __ 16th, 2003*

11. 16.1 __ 27th, 1794*

11. 16.1 __ 14th, 1869

11. 16.1 __ 21st, 1893

11. 16.1 __ 26th, 1928

________________________________

* these four did not set daily records (1827, 1828, 2003) or had their record broken later (1794, in 1866).

Two other notable warm days eclipsed by earlier records were 16.0 on 15th and 16th of 1949 (same dates as records in 1945).

[The PIT]

Sunny Sheffield at 6.5C -0.7C below normal. Rainfall unchanged.

[Summer Sun]

8.1 to the 14th

1.2 above the 61 to 90 average

0.4 above the 81 to 10 average

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Current high this month 8.1 to the 14th

[Man With Beard]

Following the ECM temperature charts on weather.us is a different story. I doubt any daily temp records will be set if ECM is right. Low 20s as daily maxes. Will still give a good boost to the CET. I think Roger is right - somewhere in the 9s looking good at the moment.

[Summer Sun]

8.2 to the 15th

1.3 above the 61 to 90 average

0.5 above the 81 to 10 average

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Current high this month 8.2 to the 15th

[The PIT]

Sunny Sheffield up to 6.7C -0.6C below normal. Rainfall 76.7mm  121.4% of average

[Summer Sun]

8.4 to the 16th

1.3 above the 61 to 90 average

0.7 above the 81 to 10 average

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Current high this month 8.4 to the 16th

[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)

8.6C to the 17th... +0.8 (12.6: +4.2)
9.1C to the 18th... +1.3 (16.3: +8.2) [Daily Record = 14.5C from 1945]
9.5C to the 19th... +1.7 (16.9: +8.8) [Daily Record = 15.4C from 1870]
9.8C to the 20th... +2.0 (16.7: +8.3) [Daily Record = 16.6C from 1893]
10.1C to the 21st.. +2.2 (16.4: +7.2) [Daily Record = 16.1C from 1893]
10.4C to the 22nd.. +2.4 (16.4: +7.0) [Daily Record = 15.4C from 2011]
10.5C to the 23rd.. +2.4 (11.5: +1.8)
10.5C to the 24th.. +2.4 (12.2: +2.5)
10.6C to the 25th.. +2.4 (11.7: +1.6)
10.6C to the 26th.. +2.3 (11.0: +0.9)

The impressive warm spell in now within sight, and a serious stretch of not just record breaking daily values, but numerous other April records are now on offer.

[The PIT]

Sunny Sheffield up to 6.9C -0.4C below normal. Rainfall Unchanged.

[Roger J Smith]

On those projections, one thing this warm spell won't do is to set an early season landmark record high CET, as 16th April 1945 was 17.0. But if any day exceeds 17.0 before 29th, then it does that. Seems that the all-time high of 19.7 (29th, 1775) will survive. 

Here is the top 15 list for warmest second half of Aprils (1772 to 2017) for the 16th to 30th mean CET ... and their warmest reading. These are also the only years to achieve 11.0 or higher for the second half of April. There was no year above 10.9 in the long stretch from 1894 to 1967 inclusive. The warmest from 1915 to 1942 inclusive was a mere 9.6. So these warmer second halves of April are mainly to be found in the first half and last quarter of the past 246 years. Since the warmth of April 2011, the average for the last half of April 2012-17 has been only 8.48 deg. 2014 was warmest at 10.39 and none of the rest exceeded 9.2. 

We will revisit this list when confirmed CET data are available around 2nd of May to see where 2018 fits into this. 

Rank __ Year ____ CET ____ max (date)

_ 1 ____ 1987 ___ 12.73 ___ 15.2 (29th)

_ 2 ____ 2011 ___ 12.58 ___ 15.8 (23rd)

_ 3 ____ 1794 ___ 12.47 ___ 16.1 (27th)

_ 4 ____ 1840 ___ 12.45 ___ 15.0 (25th)

_ 5 ____ 1893 ___ 12.35 ___ 16.6 (20th)

_ 6 ____ 2007 ___ 12.27 ___ 15.3 (24th)

_ 7 ____ 1874 ___ 12.07 ___ 15.9 (23rd)

_ 8 ____ 1775 ___ 11.99 ___ 19.7 (29th)

_ 9 ____ 1796 ___ 11.75 ___ 14.0 (23rd)

_10____ 2003 ___ 11.33 ___ 16.2 (16th)

_11____ 1968 ___ 11.31 ___ 15.5 (21st)

_12____ 1993 ___ 11.29 ___ 13.8 (30th)

_13____ 1865 ___ 11.27 ___ 14.9 (17th)

_14____ 1821 ___ 11.07 ___ 15.9 (25th, 26th)

_15____ 1975 ___ 11.05 ___ 14.5 (26th)

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I noticed while researching the max dates that April 1865 actually managed to average 11 C as a whole month right up to the 28th then dropped back with two chilly days at the end (6.3, 6.4) so its average CET 10.6 hides the fact that it was running as warm as April 2007 for most of the way. 

Also worth noting that 11th to 20th of April 1945 averaged 14.17, but much colder weather at the end of the month removed this year from the list above. 

Edited April 17, 2018 by Roger J Smith

[damianslaw]

Always surprises me how cool the average CET value for April is, given it is a rapidly warming month, with the continent rapidly warming and has a propensity for less atlantic dominated conditions and hence a greater chance of southerly/south easterly flows, just as we have ahead which can bring notable warmth. Alas I suspect northerlies and northeasterlies and easterlies off a cold continent/arctic have greater likelihood of occurring hence reason for the low CET values. If the atlantic was more active at this time of year then a much milder average CET value would occur (just like happens in Dec/Jan which symbolises the power and likelihood of the atlantic at that time of year) with associated long fetch SW airstreams.

May is the same.

 

[BornFromTheVoid]

As we embark along this impressive April warm spell, a couple of record may come under threat.

1: Most number of days with a CET of at least 15C - the previous record was 4 from 2011. The current forecast has us achieving a run of 5 consecutive days of at least 15C, starting today.
Over the CET record, 15C+ days occur on average just once every 5 years. The longest stretch without was 24 years, from 1902 to 1925.

2: Most number of days with a CET of at least 16C - the previous record was 3 from 1795. The current forecast has us achieving 5 days of at least 16C.
Over the CET record, 16C+ days occur on average just once every 18 years. The longest stretch without was 53 years, from 1950 to 2002.

3: Most number of days with a CET of at least 17C - the previous record was 2 from 1795. The current forecast has us achieving 3 days of at least 17C.
Over the CET record, 17C+ days occur on average just once every 82 years. The longest stretch without was 169 years, from 1776 to 1944.

4: The warmest April week on record was the final 7 days of 1795, which averaged 15.1C. The current forecast has the week of the 16th to the 22nd average 15.6C

I'll add some more as I find the time!

[Summer Sun]

8.7 to the 17th

1.5 above the 61 to 90 average

0.9 above the 81 to 10 average

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Current high this month 8.7 to the 17th

[The PIT]

Sunny Sheffield up to 7.2C -0.3C below average. Rainfall unchanged

[Summer Sun]

9.1 to the 18th

1.8 above the 61 to 90 average

1.3 above the 81 to 10 average

______________________________________

Current high this month 9.1 to the 18th

[Roger J Smith]

On 4/18/2018 at 02:48, BornFromTheVoid said:

As we embark along this impressive April warm spell, a couple of record may come under threat.

1: Most number of days with a CET of at least 15C - the previous record was 4 from 2011. The current forecast has us achieving a run of 5 consecutive days of at least 15C, starting today.
Over the CET record, 15C+ days occur on average just once every 5 years. The longest stretch without was 24 years, from 1902 to 1925.

2: Most number of days with a CET of at least 16C - the previous record was 3 from 1795. The current forecast has us achieving 5 days of at least 16C.
Over the CET record, 16C+ days occur on average just once every 18 years. The longest stretch without was 53 years, from 1950 to 2002.

3: Most number of days with a CET of at least 17C - the previous record was 2 from 1795. The current forecast has us achieving 3 days of at least 17C.
Over the CET record, 17C+ days occur on average just once every 82 years. The longest stretch without was 169 years, from 1776 to 1944.

4: The warmest April week on record was the final 7 days of 1795, which averaged 15.1C. The current forecast has the week of the 16th to the 22nd average 15.6C

I'll add some more as I find the time!

It is a singularity on a par with Dec 2015. BTW any reference to 1795 in the above should read 1775. I will  bump my earlier posted list of the top CET daily values. Some are hiding behind the 1775 records.

[Roger J Smith]

On 4/14/2018 at 11:18, Roger J Smith said:

With that in mind, current top 14 April CET days (four tied 11th) are:

 1. 19.7 __ 29th, 1775

 2. 17.4 __ 30th, 1775

 3. 17.0 __ 16th, 1945

 4. 16.9 __ 28th, 1775

 5. 16.8 __ 30th, 1827*

 6. 16.6 __ 20th, 1893

 7. 16.5 __ 27th, 1866

 8. 16.3 __ 29th, 1828*

 8. 16.3 __ 15th, 1945

10. 16.2 __ 16th, 2003*

11. 16.1 __ 27th, 1794*

11. 16.1 __ 14th, 1869

11. 16.1 __ 21st, 1893

11. 16.1 __ 26th, 1928

________________________________

* these four did not set daily records (1827, 1828, 2003) or had their record broken later (1794, in 1866).

Two other notable warm days eclipsed by earlier records were 16.0 on 15th and 16th of 1949 (same dates as records in 1945).

move over 2, 3 and 4 ... 26 max today and 10 min would be good for 18.0. Earliest on record. (18th provisionally 16.7 new 6th on above list. Note current 5th place 30-4-1827 hiding behind daily record 2nd place 30-4-1775.

[The PIT]

Sunny Sheffield up to 7.7C +0.2C above normal. Rainfall unchanged. Another huge for today as well.

[johnholmes]

Even warmer than yesterday at 28.7 C, the hottest since 17 July 2017, mostly cloudless and hardly any breeze

 

[The PIT]

Just looking at the latest GFS and if comes off the last five days look below average again. Funny old month this one. Just below 26C and the trees only just beginning to come out.