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. 

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

Historic CET summary for March  

1981-2010 6.6C (30 years)  

1991-2020 6.7C (30 years)  

2001-2020 6.5C (last 20 years)  

Last March was average with a CET of 6.7C. 2017 and 2019 were very warm with 8.7C and 7.8C respectively. 2016 and 2018 were cold with 5.7C and 4.9C respectively. So we have had a bit of everything in the past few years.   

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

Direct link to larger version of the chart

Current model output   

850s start the month above average but then turn colder until the mid-point of the month. After that there is no signal which is fairly normal beyond 2 weeks out

GEFS 850s https://www.wetterzentrale.de/de/show_diagrams.php?geoid=49069&model=gfs&var=2&run=99&lid=ENS&bw=1

GFS T2m https://www.wetterzentrale.de/de/show_diagrams.php?geoid=49069&model=gfs&var=5&run=99&lid=ENS&bw=1

ECM looks to be similar to GFS with temperatures likely to return to average fairly quickly after perhaps a week of cooler weather

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/metofficegovuk/pdf/business/public-sector/civil-contingency/3moutlook-mam-v1.pdf

65% chance of a near average month. However, the chance of colder conditions is greater than in recent years. 

The SSW in January and the current phase of the MJO both favour the jet stream being somewhat south of its normal track.

METCHECK present figure for this morning ~~~~ 1.72c. -4.44c. 

It seems I got a bit too scientific in the Feb thread - apologies where due.

I promise to be better behaved this month, even if it unexpectedly turns out to be the frigid month that February was meant to be .

I do like your broader scale driver musings and February did seem one of those butterfly moments where just a bit too much energy hit the block at just the wrong angle in the end, which flipped us from a further 7-10 days of cold air to mild or very mild and that was that. Bit amusing for my guess as I'd hedged on a cold period with warmer last third still giving a below average month but not significantly so.

Looking at the current ECM ens I'm quite happy with my March guess although I always find spring a touch tricky* as the difference between a cool set up and a very mild one can be a matter of a relatively small adjustment to LP track or HP placement.

*an uncharitable person would suggest I find all months tricky judging by some on my placings in this competition

Thanks Hippydave 

CET & general long-range forecasting shenanigans aside, it was a fascinating month from a scientific perspective - the SSW may have been unique in the observation record, while the lengthy period of enhanced thunderstorms across the tropical Pacific Ocean (MJO-like activity) was very unusual to see during a La Nina.

Generally, the March signals seem very muted to me at this time. There are signs of a new round of enhanced tropical Pacific thunderstorm activity which would support a colder month than average, but on the other hand, the polar vortex has become unusually strong now and looks to remain so for at least the next fortnight.

My estimation is that the net result will be a changeable month that struggles to produce notably warm or cold spells of weather that's more than fleeting. So, I've gone close to the long-term average for this one.

Statistically speaking, going near-average is inherently less likely to result in a big error (one of the main drawbacks of using a direct error measure)... but somehow that doesn't reassure me much! 

Met Office Hadley         4.0c     Anomaly      -0.6c   Provisional to 2nd

Metcheck                      3.3c     Anomaly      -2.93c

Netweather                   4.25c   Anomaly      -2.06c

Peasedown St John     5.1c     Anomaly      -1.8c.  

The provisional Hadley of 4.0°C for 1st-2nd is a whacking great 3.9°C below what I got from the GFS 12z of 28th Feb!

Looking at the observation data I can see, it looks like it was about that much colder both by day and night than the model predicted. Pretty appalling!

Based on that, my estimate for the March CET should have been 0.19°C lower than I sent. Not a big loss or unwitting gain (depending on how things actually turn out) at this stage but hopefully GFS won't continue to be so far out, as it's all I had to work with as a basis for the 'starting position' onto which the various signals are applied.

Projecting using the latest GFS run (06z of today) suggests my estimate should have been 0.30°C lower. Could be worse - but it's becoming apparent that a decent warm spell is needed at some point for those who predicted in the high 6s or higher to be near the mark.

This, though, was part of my 'prediction' for the month - so nothing new there. The basis is some support from the tropics (Gusty will groan at this point) combined with an unusually strong polar vortex. Let's see if that comes through.

Grrr. boring ! lol 

It wasn't just the models that got it wrong. I think that forecasts for yesterday in general were largely inaccurate. The low cloud and fog was more stubborn than expected and that suppressed temperatures in many parts of the UK, including the all important CET zone. 

Met Office Hadley         4.2c       Anomaly       0.4c provisional to 2nd

Metcheck                      2.99c     Anomaly       -3.17c

Netweather                   4.05c     Anomaly       -2.26c

Peasedown St John     4.2c      Anomaly       -2.7c.            

Here is a first look at the March CET tracker

Chart 1

Chart 2

Here are the March predictions

Table

Met Office Hadley       4.2c      Anomaly     -0.3c Provisional to 4th

Metcheck                    3.28c    Anomaly     2.88c

Netweather                 4.15c    Anomaly     -2.16c

Peasedown St John    4.8c     Anomaly     -2.1c.

Met Office Hadley       3.1c      Anomaly     -0.4c provisional to 5th

Metcheck                    3.19c    Anomaly     -2.37c

Netweather                 4.16c    Anomaly     -2.15c

Peasedown St John    3.47c    Anomaly     -3.43c.  

Average CET estimate for 1st-5th March from the GFS runs of the last few days of February: 6.3°C.

The actual is 3.2°C lower. That's ridiculous and makes a mockery of projection efforts that have to make do with the model for the short-term 'starting point' because it's the only one with freely available, easily readable max temp predictions .

I estimate this to now have a -0.4 to -0.6°C impact on the final CET of the month. So my estimate would have been something like 6.4°C instead of 6.93°C.

Ah well - maybe it will turn astoundingly warm... sadly only glimmers of that in the model output lately. The warmest deterministic run of the past few days, the GFS 12z of yesterday, lifted my estimate up to the high 6s °C as of 21st.

Most runs have had it somewhere in the 5s at most up to that point.

Some actually hint at a cold spell from the east... as far against the grain of a La Nina, strong polar vortex combo March as that would be, it's still making me nervous!

Incidentally, ECM's still going for the MJO waking up in phase 8 by Wednesday, which would raise the odds of a colder outcome, though the strong polar vortex still keeps the probability suppressed - it would have to cleanly isolate itself over by Siberia. More often than not, we instead see a 'tail' of it hanging back across Greenland or thereabouts.

GFS is keen on the MJO waking up in phase 1 instead but the implications are similar.

Conversely, if it then moves on to phase 2, the typical response is a big height rise over Europe leading to unusually warm conditions. MJO arrival there suggested to be by 20th, so a warm final week of the month is feasible. Long way to go though!

Overall, my confidence in landing close to the final CET is already not great. The large overestimation of temperatures by GFS is a big part of that!

I had the same experience last month - the spread of estimates was near 1°C higher than I'd been anticipating, which really caught me out and amplified the impact of the large error. Even with all the extended cold signals at hand, I don't think I'd have predicted so low if I'd known.

Iam suprised to that so many have gone so high. Personally i cant see how this month is going to end up much above 6c

Met Office Hadley        3.9c       Anomaly       -0.8c provisional to 6th

Metcheck                     2.99c     Anomaly       -3.19c

Netweather                  4.0c       Anomaly      -2.31c

 Peasedown st John     4.0c      Anomaly      -2.9c. 

Met Office Hadley         3.5c        Anomaly       -1.0c provisional to 7th

Metcheck                      3.06c      Anomaly       -3.10c

Netweather                   3.86c      Anomaly       -2.45c

Peasedown St John      3.2c       Anomaly       -3.7c.     

Don't underestimate the power of a warm spell in the 2nd half of March...

The GFS 06z gave us a likely overly extreme version of that but get this - it gives me a rough CET estimate in the low 6s as soon as 17th and it only gets higher from there.

Much higher, in fact, reaching the dizzy mid-7s for 22nd-23rd.

Odds are, we don't see the high set up in such a warm position and stick there for a week or so - but it shows the possibilities that this time of year brings.

12z GFS is looking much more realistic - but still good for a CET well into the 6s by 21st. Bearing in mind we usually see a climb of the CET in the final third, I think there's plenty of scope for a final CET in the mid-6s to mid-7s.

BUT...

The ECM runs of late can't be ignored. They've been tending to keep the Azores High further west, with the UK staying predominantly chilly through to at least 16th. Despite the mode's tendency to over-amplify a bit in the 7-10 day range, it's keeping me nervous!