This thread is for all comments, discussion and analysis of temperatures in the UK during March, with particular emphasis on the Central England Temperature (CET), for the simple reason that it is the longest running temperature series in the world with over 360 years of data. But you can comment on any interesting temperature statistics or data from across the UK, including your own back yard.

February was a very mild month after a very cold start. March is looking somewhat cooler after a very mild start

For those taking part in the competition all CET predictions for March should be sent directly to me via the forum private message system. Do not post them directly into the thread.

The deadline for predictions this month is 2359 on Sunday evening (3 March). 

Now on to some data for March:

Historic CET summary for March

1971-2000 6.3C (30 years)

1981-2010 6.6C (30 years)

1999-2018 6.6C (last 20 years)

Last March was cold with 4.9C largely to the Beast from the East. The previous March was very mild at 8.7C.

Here is a chart of the March CET for all years since 1961:

Direct link to larger version of the chart

Latest model output - 12z 1 March

GFS (12z) - turning cooler after a mild start

http://www.wetterzentrale.de/de/show_diagrams.php?geoid=49069&model=gfs&var=2&run=12&lid=ENS&bw=

GEM (12z) - similar to GFS

http://www.wetterzentrale.de/de/show_diagrams.php?model=gem&var=2&geoid=49069&lid=ENS&bw=

Multi Op - fairly good agreement on a sine wave pattern indicating unsettled Atlantic dominated conditions

http://www.wetterzentrale.de/de/show_diagrams.php?model=multi&var=2&geoid=49069&lid=OP&bw=

The ECM ENS T2m temperatures for De Bilt show a very consistent signal throughout. More scatter of course in the longer range but the mean is quite consistent for the whole run after the first three days

http://cdn.knmi.nl/knmi/map/page/weer/waarschuwingen_verwachtingen/ensemble/detail/ensemble-verwachtingen-detail10.png

Met Office contingency planners outlook 

https://www.metoffice.gov.uk/binaries/content/assets/mohippo/pdf/public-sector/forecast-temp-mam-v2.pdf

Shows a signal for higher than average probability of above average temperatures for the Spring

Temperature analogues

In general, recent years with a very warm February have also been followed by a warm or very warm March.

If we look at January and February we see that the best matches for the year are 2017, 2011 and 1961. March 2017 was very warm whereas March 2011 was close to average. March 1961 was very warm.

So the analogues would suggest the likelihood of an above average month with the possibility of a very warm month again.

First look at March temperature tracker

After a very mild start temperatures could then turn much cooler. Even so by the middle of the month we could still be about 1C above average.

My guess is in and without giving too much away here, I'm going for another warmer than average month, but not to the same extent as what we saw during February and without any records being broken this time.

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Met Office Hadley         7.9c.        Anomaly       3.3c.  Provisional to 1st.

MetCheck                     7.63c        Anomaly       1.47c

Netweather                   8.3c         Anomaly        2.01c.

Canvey Island               8.4c         Anomaly        1.3c         Davis  Vantage Pro2 

Cheadle Hulme              9.5c         Anomaly        2.15c           "      "           "

Clevedon Weather          9.5c        Anomaly         2.29c           "      "           " 

Darwen                         8.9c        Anomaly         2.69c         Unknown Just an image on Wunderground

Hexham                        7.9c        Anomaly         2.5c           Ambient Weather WS-1001

Linford                          10.1c      Anomaly         4.04c          Davis Vantage  Pro 2

Mount Sorrel                  7.9c       Anomaly          1.84c            "      "            "  

Forest Town Mansfield     8.1c       Anomaly          2.58c          La Crosse Technology 320-2315

Peasedown St John          9.8c      Anomaly           3.87c           WH 1080

Treviskey Redruth            9.4c      Anomaly           1.74c.         Davis Vantage Pro2

Mean of my 10 watched stations with a 6-year average  8.85c.  Anomaly  2.5c.                 

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Met Office Hadley          8.7c.      Anomaly       4.2c.    Provisional to 2nd.

Metcheck                       8.38c     Anomaly       2.22c

Netweather                    9.12c     Anomaly       2.83c

Linford                          10.8c      Anomaly       4.74c

Clevedon Weather          10.0c      Anomaly       2.79c

Peasedown St John         10.8c     Anomaly        4.87c

Treviskey Redruth           9.8c       Anomaly        2.14c 

Mean of my 10               9.38c     Anomaly        3.03c.   

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Met Office  Hadley           8.9c.      Anomaly      4.3c

Metcheck                         8.07c     Anomaly      1.91c

Netweather                      9.15c     Anomaly      2.86c.    

Darwen                            8.0c      Anomaly       1.79c

Hexham                           6.5c      Anomaly        1.1c

Forest Town Mansfield       7.7c

Mean of my 10                 8.67c.   Anomaly       2.32c.     

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Met Office Hadley           8.1c.      Anomaly      3.6c. Provisional to 4th.

Metcheck                        7.44c      Anomaly     1.28c    

Netweather                     8.49c      Anomaly     2.2c

 

Mean of my 10 stations   8.5c       Difference     1.33c.

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Currently very tricky to gauge where the CET will be heading past mid-month, as it appears there will either be a counteracting of the usual warming trend or some acceleration of it, depending on whether amplified ridges position to our west or to our south.

The impact on the CET will be drastic.

For example, the GFS 06z and 12z runs, despite some variation in the timing of colder and milder interludes, both gave me an estimate CET of 6.2*C to 14th following 4 chilly nights (with min CET returns dipping to within a couple of freezing), but then, while the 06z favoured ridging out west and took the CET slightly downward to 6.0*C as of 20th, the 12z increasingly preferred ridging to our south and lifted the CET to 6.5*C as of 20th - with it on a sharp upward trend having gained 0.4*C in the space of two days.

 

My initial CET estimate was in the mid-7s but then I got cold feet and adjusted it down to 7 exactly as the models remained insistent on it turning markedly colder than usual for at least the middle-third of the month.

Five days later, I've still got little confidence in which estimate will land nearer the mark .

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Met Office Hadley          7.9c.       Anomaly       3.3c.  Provisional to 5th.

Metcheck                      7.68c       Anomaly       1.52c

Netweather                   8.23c       Anomaly       1.94c

Hexham                        6.7c         Anomaly       1.3c

Linford                          9.2c         Anomaly       3.14c

Peasedown  St John       9.4c         Anomaly       3.47c

Treviskey Redruth          9.2c         Anomaly       3.47c

Mean of my 10           8.5c       Anomaly      2.15c.

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My initial CET estimate was in the mid-7s but then I got cold feet and adjusted it down to 7 exactly as the models remained insistent on it turning markedly colder than usual for at least the middle-third of the month.

Five days later, I've still got little confidence in which estimate will land nearer the mark .

 

I'd be happy with either, perhaps somewhere between the two  

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My initial CET estimate was in the mid-7s but then I got cold feet and adjusted it down to 7 exactly as the models remained insistent on it turning markedly colder than usual for at least the middle-third of the month.

Five days later, I've still got little confidence in which estimate will land nearer the mark .

I had to make my prediction on 13th Feb due to holidays and had no indication from the models that far ahead.  I plumped for 7c and I’m happy with that at the moment but I need to gain a lot of points to get me into the top half of the table!  

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Fingers crossed for us three then .

Judging by the tendency in the model runs to keep putting back the greater build of mid-Atlantic ridging or even send that main ridge development into Europe while the -NAO pattern becomes west-based (a more late April-like Nino outcome but not implausible), I'm leaning increasingly far toward my original mid-7s estimate having been the better call.

Not fully off the fence though, as it would be unusual to see mid-Atlantic ridging fail to materialise in a significant way for at least one spell during a Nino-driven March. The trouble is that unusual has tended to be the usual lately! 

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Met Office Hadley         8.1c.      Anomaly      3.4c. Provisional to 6th.

Metcheck                      7.76c     Anomaly      1.60c

Netweather                   8.54c     Anomaly      2.25c

Hexham                       6.8c        Anomaly      1.4c

Forest Town Mansfield   7.9c        Anomaly      2.32c

Peasedown St John       9.7c        Anomaly      3.77c

Treviskey  Redruth        9.0c        Anomaly      1.34c

Mean of my 10 stations 8.47c      Anomaly      2.12c.                                      

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Met Office Hadley         7.9c.      Anomaly     3.1c. Provisional to 7th.

Metcheck                     7.49c      Anomaly     1.32c

Netweather                  8.32c      Anomaly     2.03c      

Hexham                       6.0c        Anomaly     0.6c.

Forest Town Mansfield   7.4c        Anomaly     1.82c

Treviskey Redruth         8.6c        Anomaly     0.94c

Peasdown St John         9.5c        Anomaly     3.57c

Mean of my 10 stations  8.23c.    Anomaly     1.88c.   

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Hmm perhaps I spoke too soon?

The latest two GFS runs take my estimate down to 6.6*C as of 17th, after which the 00z has a very balmy interlude yet only raises it to 6.8*C as of 21st before it turns unusually chilly with a drop down to 6.5*C as of 23rd, while the 06z doesn't vary as much either way but has overall colder nights with the estimate down to just 6.1*C as of 23rd.

With near-LTA conditions thereafter, then with the 00z having occurred the CET would finish in the high 6s, and with the 06z having occurred the low-mid 6s.

However - the 00z ECM isn't as enthusiastic to turn things markedly chilly D9-D10 and I'm wary of GFS' tendency to be a bit too eager with patterns involving mid-Atlantic ridges.

Still, the fact that I'm contemplating near or even a little below-average CET outcomes after such a mild start compared to normal really highlights the size of the usual warming trend during March - and the fact that the Hadley CET anomalies are based on the long-term average for the specific date, not the month as a whole; compared to the month mean LTA the current figures are only about +1*C for anomaly.

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Met Office Hadley           7.5c.    Anomaly    2.7c. Provisional to 8th.

Metcheck                        7.44c    Anomaly    1.29c

Netweather                     8.09c    Anomaly    1.8c

Hexham                          6.0c      Anomaly     0.6c

Forest Town Mansfield      7.6c      Anomaly     2.02c

Treviskey Redruth            8.9c      Anomaly     1.24c

Mean of my 10 stations  8.22c    Difference    1.87c.      

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Hmm perhaps I spoke too soon?

The latest two GFS runs take my estimate down to 6.6*C as of 17th, after which the 00z has a very balmy interlude yet only raises it to 6.8*C as of 21st before it turns unusually chilly with a drop down to 6.5*C as of 23rd, while the 06z doesn't vary as much either way but has overall colder nights with the estimate down to just 6.1*C as of 23rd.

With near-LTA conditions thereafter, then with the 00z having occurred the CET would finish in the high 6s, and with the 06z having occurred the low-mid 6s.

However - the 00z ECM isn't as enthusiastic to turn things markedly chilly D9-D10 and I'm wary of GFS' tendency to be a bit too eager with patterns involving mid-Atlantic ridges.

Still, the fact that I'm contemplating near or even a little below-average CET outcomes after such a mild start compared to normal really highlights the size of the usual warming trend during March - and the fact that the Hadley CET anomalies are based on the long-term average for the specific date, not the month as a whole; compared to the month mean LTA the current figures are only about +1*C for anomaly.

I did wonder about that, the anomolies didn't seem quite right relative to the month as a whole.

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Blimey - this really is a tough month to nail down! Yes, another one! 

The MJO's powered on into P4 against all modelling predictions, and this has taken apart any notion of more than a day or two of appreciable mid-Atlantic ridging west of the UK.

P4 works against the Nino background and promotes height rises near-south of the UK... hence GFS starting to play around with that a lot in recent runs. Unclear whether the Nino forcing will do enough to slow the Atlantic westerlies sufficiently for the associated high pressure to build north across the UK but if it does, the final third of the month could feel more like May than March.

In which case, depending on how cool the nights were, a final CET in the 8s would become most likely, with 9s not out of the question.

This defiant MJO behaviour even after the Nino pattern strengthened markedly in the past fortnight really is fascinating.

It seems to me that a warm Indian Ocean, on top of the climatic warming trend which has been particularly strong in that region during the past half-century, is giving the tropical convection enough uplift from the surface to keep it going unusually far into the unfavourable (descending air from aloft) region of the Walker Cell (large-scale circulation that responds significantly to El Nino and La Nina events; typically, descending air isn't over the Maritime Continent but this changes when El Nino is in place).

With this comes the potential for a greater incidence of unusual weather patterns such as we saw in the final week of Feb in which the amplifying effect of El Nino on the Atlantic-Europe sector doesn't propagate as far north as usual, causing it to build unusually strong highs at latitudes UK-southward instead of UK-northward.

Last May through mid-July, a similar unusual combination gave us El Nino-like Azores High extension northeast (note that the responses differ between seasons; the poleward ridges locate further east in summer), but also La Nina-like strengthening of that high across the Azores, meaning we had an unusually strong high ridging a good deal further northeast than is usually seen when it's at that strength. Hence it was so unusually dry and persistently warm to hot.

Summer 2019 will probably either be predominantly Nino-driven with a tendency for repeating spells of increasingly hot weather than then undergo thundery breakdowns, or driven by another Nino-Nina hybrid situation with a lot of similarities to last summer.

 

CFSv2 has been unusually consistent lately and has generally favoured patterns resembling a hybrid outcome for May-Jun.

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Met Office Hadley         7.5c.      Anomaly    2.9c. Provisional to 9th.

Metcheck                     7.32c      Anomaly    1.16c

Netweather                  8.1c        Anomaly    1.81c

Canvey Island               9.0c       Anomaly     1.9c

Cheadle Hulme              7.6c       Anomaly     1.25c

Clevedon Weather          9.0c       Anomaly     1.79c

Darwen                         7.4c       Anomaly     1.19c

Hexam                          5.6c       Anomaly     0.2c

Linford                          8.9c       Anomaly     2.84c

Mount Sorrel                 7.5c       Anomaly      1.44c

Forest Town Mansfield    7.3c       Anomaly      1.72c

Peasedown St John        9.6c       Anomaly      3.67c

Treviskey Redruth          9.0c       Anomaly      1.34c.

Mean of my Watched 10 stations using a 6-Year average  8.9c.  Difference 2.55c.       

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Latest charts for March. The CET is likely to oscillate around 7.5C overt the next 10 days before potentially climbing again in the final week of the month if high pressure begins to move in. I think a CET above 8C is still quite likely based the current output. If cooler conditions persist for longer then something nearer the mid 7's might be more likely.

Apologies for the delay. Here is the list of predictions for March.

Link to full size chart