July 2015 CET forecasts

[Summer Sun]

16.4c to the 27th

 

0.4c above the 61 to 90 average

 

0.2c below the 81 to 10 average

[The PIT]

No change for sunny Sheffield still on 16C. Should be 15.9 tomorrow with a finishing zone of 15.8C 

[damianslaw]

A 50/50 chance we could end up below the 61/90 average or bang on the average, will depend on any marked adjustments. I think we will just creep in below... very few would have anticipated this on the 1 July 2015, many of those in the media suggesting hottest July on record should have egg firmly on face.

[Weather-history]

Anyone seen the film "On the Waterfront"? I can almost see this July after it is over sitting back and quoting Marlon Brando's famous lines

Edited July 29, 2015 by Weather-history

[Weather26]

16.4c to the 28th

 

0.3c above the 61 to 90 average

 

0.2c below the 81 to 10 average

Edited July 29, 2015 by Weather26

[Summer Sun]

 

16.4c to the 28th

 

0.3c above the 61 to 90 average

 

0.3c below the 81 to 10 average

 

 

0.2c below the 81 to 10 average

[The PIT]

Sunny Sheffield down to 15.9C -0.8C below normal.

[Relativistic]

A 50/50 chance we could end up below the 61/90 average or bang on the average, will depend on any marked adjustments. I think we will just creep in below... very few would have anticipated this on the 1 July 2015, many of those in the media suggesting hottest July on record should have egg firmly on face.

Even my guess is looking like it could be too high, at 16.2C. I did think people were overdoing it at the beginning of the month, with opinions being swayed by the first few days.

[BornFromTheVoid]

The CET should be right on the boundary between 16.1 and 16.2C before corrections, so probably 15.7C to 16.2C after. EDIT: Slight miscalculation, the CET should be on 16.1C (around 16.08C) before corrections, so 15.7C to 16.1C after.

 

Thanks, I have a daily file downloaded that I have been updating manually since 2011. Just didn't think about the 30-day drop regardless of date. I suppose the real comparison is 30-day drop divided by the standard deviation in daily temperatures because I figure that summer must be about 2/3 of winter on that scale (s.d.) so 8 deg in July is comparable to 12 deg in January. Or if it was 4/5, then 8 is comparable to 10, etc.

 

This may in fact be the most significant 30-day differential on this scale when you consider that factor. The drop in October 1985  was larger in absolute terms but it would average about 2 deg at random (because temperatures are usually falling that much throughout October) so that should be subtracted, whereas July would average almost a degree up so that should be added for comparison, as well as the slightly larger spread of October means compared to July means.

 

Agreed. I'll try work on something like that if I have the time in the next few days. Perhaps get the average change for every 30 day period and then calculate anomalies rather than just looking at absolutes.

Edited July 30, 2015 by BornFromTheVoid

[Summer Sun]

16.3c to the 29th

 

0.2c above the 61 to 90 average

 

0.4c below the 81 to 10 average

[The PIT]

Sunny Sheffield down to 15.8C -0.9C below average 15.7 tomorrow if tonight is cold.

[damianslaw]

Bang on or 0.1/0.2 degree below 61-90 average most likely now... a disappointing month in the main despite the exceptional heat of the  1 July, which will quite possibly end up the only talking point of summer 2015.

[Weather-history]

Thanks, I have a daily file downloaded that I have been updating manually since 2011. Just didn't think about the 30-day drop regardless of date. I suppose the real comparison is 30-day drop divided by the standard deviation in daily temperatures because I figure that summer must be about 2/3 of winter on that scale (s.d.) so 8 deg in July is comparable to 12 deg in January. Or if it was 4/5, then 8 is comparable to 10, etc.

This may in fact be the most significant 30-day differential on this scale when you consider that factor. The drop in October 1985 was larger in absolute terms but it would average about 2 deg at random (because temperatures are usually falling that much throughout October) so that should be subtracted, whereas July would average almost a degree up so that should be added for comparison, as well as the slightly larger spread of October means compared to July means.

I think March 2013 would make an interesting case study.

It was 4.9C on the 9th and to drop to 2.7C by month's end may not seem a lot but you have to take into consideration that March is a month that climatically on average, gets warmer as the month progresses.

What is the climatic probability of that happening?

Incidentally, July 1968 started off as 21.8C and ended at 15.0C

Edited July 31, 2015 by Weather-history

[Summer Sun]

16.2c to the 30th

 

0.1c above the 61 to 90 average

 

0.5c below the 81 to 10 average

[The PIT]

Final CET for Sheffield 15.7C rounded up. Todays higher than expected Max making sure it wasn't lower. -1C f below average.

[Man With Beard]

Even my guess is looking like it could be too high, at 16.2C. I did think people were overdoing it at the beginning of the month, with opinions being swayed by the first few days.

Yes indeed - and the same thing happening right now I think on the August CET thread. Beware precarious beginning of month huge anomalies - I will in future!!

[Don]

Yes indeed - and the same thing happening right now I think on the August CET thread. Beware precarious beginning of month huge anomalies - I will in future!!

 

True, but after such a hot start to the month, the odds for a close to average month overall were pretty slim, especially considering July is the warmest month of the year on average and doesn't normally have a cooling trend as the month progresses.

Edited August 1, 2015 by Don

[Summer Sun]

July confirmed as 15.91C

 

http://www.metoffice.gov.uk/hadobs/hadcet/cet_mean_2015

[North-Easterly Blast]

Final Hadley July CET is 15.9 (15.91).  So we are just below the 1961-90 average.  Although even by recent standards this is not unusual with the Julys of 2007, 2011 and 2012 all cooler than 2015.  Further back the Julys of 1993, 1998, 2000 and 2004 were also cooler.  July 2015 has been what you may call a "pear shaped" summer month - much like a summer version of February 2009.  July 2015 started with a notable heatwave and it remained on the warm side for much of the first half and then a spell of notably cool weather in the later part of the month put the overall mean slightly below average in the end despite such a notable heatwave at the start.

 

July 2015 also had a cooler second half than the first - a rarity in recent times.  This has only happened in 2009, 2007, 2005, 1987, 1986, 1985 in the last 30 years although I am not so sure before that.

[BornFromTheVoid]

I'll post up more stats in a while, but a little teaser for now.

 

The last week of July was the 8th coldest on record, and the coldest since 1920!

[Milhouse]

It felt like it as well, considering it should be one of the warmest weeks of the year.

[Gael_Force]

Final Hadley July CET is 15.9 (15.91).  So we are just below the 1961-90 average.  Although even by recent standards this is not unusual with the Julys of 2007, 2011 and 2012 all cooler than 2015.  Further back the Julys of 1993, 1998, 2000 and 2004 were also cooler.  July 2015 has been what you may call a "pear shaped" summer month - much like a summer version of February 2009.  July 2015 started with a notable heatwave and it remained on the warm side for much of the first half and then a spell of notably cool weather in the later part of the month put the overall mean slightly below average in the end despite such a notable heatwave at the start.

 

July 2015 also had a cooler second half than the first - a rarity in recent times.  This has only happened in 2009, 2007, 2005, 1987, 1986, 1985 in the last 30 years although I am not so sure before that.

Wet months, though. Surely this year is a bit more remarkable in that it has been predominately dry with a good sunshine total.

[Weather-history]

Starting from 2001, it took to September 2008 to record the 24th month of the decade 2001-10 that was below the 1971-2000 average.

July 2015 is the 24th month of the decade 2011-20 to be below the 1971-2000 average and that's despite that there were only two months below the 1971-2000 average from July 2013 until January 2015 inclusive.

Months below the 1971-2000 average since January 2001

Jul 2015: 15.9 (-0.6)

Jun 2015: 14.0 (-0.1)

May 2015: 10.8 (-0.5)

Feb 2015: 4.0 (-0.2)

Aug 2014: 14.9 (-1.3)

Nov 2013: 6.2 (-0.7)

Jun 2013: 13.6 (-0.5)

May 2013: 10.4 (-0.9)

Apr 2013: 7.5 (-0.6)

Mar 2013: 2.7 (-3.6)

Feb 2013: 3.2 (-1.0)

Jan 2013: 3.5 (-0.7)

Dec 2012: 4.8 (-0.3)

Nov 2012: 6.8 (-0.1)

Oct 2012: 9.7 (-0.7)

Sep 2012: 13.0 (-0.6)

Jul 2012: 15.5 (-1.0)

Jun 2012: 13.5 (-0.6)

Apr 2012: 7.2 (-0.9)

Feb 2012: 3.8 (-0.4)

Aug 2011: 15.4 (-0.8]

July 2011: 15.2 (-1.3)

June 2011: 13.8 (-0.3)

Jan 2011: 3.7 (-0.5)

Dec 2010: -0.7 (-5.8]

Nov 2010: 5.2 (-1.7)

Oct 2010: 10.3 (-0.1)

Aug 2010: 15.3 (-0.9)

May 2010: 10.7 (-0.6)

Mar 2010: 6.1 (-0.2)

Feb 2010: 2.8 (-1.4)

Jan 2010: 1.4 (-2.8]

Dec 2009: 3.1 (-2.0)

Jul 2009: 16.1 (-0.4)

Feb 2009: 4.1 [-0.1]

Jan 2009: 3.0 [-1.2]

Dec 2008: 3.5 (-1.6)

Oct 2008: 9.7 (-0.7)

Sep 2008: 13.5 (-0.2)

Jul 2008: 16.2 (-0.3)

Jun 2008: 13.9 (-0.2)

Apr 2008: 7.9 (-0.2)

Mar 2008: 6.1 (-0.2)

Dec 2007: 4.9 (-0.2)

Aug 2007: 15.4 (-0.8]

July 2007: 15.2 (-1.3)

Aug 2006: 16.1 (-0.1)

Mar 2006: 4.9 (-1.4)

Feb 2006: 3.7 (-0.5)

Dec 2005: 4.4 (-0.7)

Nov 2005: 6.2 (-0.7)

July 2004: 15.8 (-0.7)

Dec 2003: 4.8 (-0.3)

Oct 2003: 9.2 (-1.2)

Feb 2003: 3.9 (-0.3)

Oct 2002: 10.1 (-0.3)

Jul 2002: 16.0 (-0.5)

Dec 2001: 3.6 (-1.5)

Sep 2001: 13.4 (-0.3)

Apr 2001: 7.7 (-0.4)

Mar 2001: 5.2 (-1.1)

Jan 2001: 3.2 (-1.0)

Edited August 1, 2015 by Weather-history

[The PIT]

Sunny Sheffield 15.7C and with below average rainfall as well despite only five dry days.

[BornFromTheVoid]

An interesting month from a stats point of view, split into 3 distinct periods: the warm first 4 days averaging 3.8C above the 81-10 average, then a close to average 18 days (-0.4C anomaly) followed by a cool final 9 days (-3.6C anomaly). The warmest day, 24.6C on the 1st, was 8.7C above average, while the coolest day, 12.7C on the 31st, was 4.5C below average (but not the coolest day anomaly-wise, which was 12.8C on the 29th, 4.9C below average).

 

Below is the daily CET corrections, followed by the summer CET so far compared to the record's averages and extremes.

 

 

 

 

 

A few stats, July 2015:

 

• The joint 3rd warmest July day on record (24.6C)
• The joint 4th warmest CET day on record (24.6C)
• The 3rd warmest July maximum on record (32.7C)
• The 6th warmest CET maximum on record
• The earliest date to record a daily CET of greater than 23.0C, 23.5C, 24.0C, and 24.5C.
• First to record 3 or more days below 13.0C in July since 1997
• First to record 3 or more days below 13.0C during the last week of July since 1920
• The 8th coldest last week of July on record, and coldest since 1920
• 5th coldest July minimum on record, 5.4C on the 31st
• The joint 10th biggest July drop from the first half to the second half of the month (-2.5C)
• 3rd largest difference between the highest and lowest daily average for any July on record (11.9C)
• Largest range on record between the July highest max and lowest minimum (27.3C)

 

If anyone has any questions or requests for specific stats, feel free to ask and I'll do my best!

 

EDIT: I'll add in more stats during the day if I find them and put the new ones in italics.

Edited August 1, 2015 by BornFromTheVoid