April CET

[The watcher]

Breaking records or not breaking records it's all just dependant on the source of the air, April can easily be the complete opposite and beat the coldest april on record. I would understand the great concern if we had a significantly above average month with synoptics that would usually provide an average outcome, but expecting this april not to be well above average considering the exceptional synoptics it has produced is just a bit silly to me.

[Optimus Prime]

What many scienists are arguing is whether the rather small warming the earth has seen the last 60 years or so is inturn physically changing the pressure patterns around the globe which allows much more extreme and peristsant heatwaves, like seen last year and many previous years recently to become more frequent and peristsant.

I did wonder (and posted my thoughts a few times last year) whether the cool weather would be replaced with an intense warm rebound of weather as the patterns shift back towards 2006/2007. I think we're probably seeing this right now.

[reef]

Hadley is 11.4C to the 20th. Yesterday was 13.5C.

A min last night of 7.9C, so today should see another decent rise.

[Don]

I did wonder (and posted my thoughts a few times last year) whether the cool weather would be replaced with an intense warm rebound of weather as the patterns shift back towards 2006/2007. I think we're probably seeing this right now.

Well I certainly hope not but must admit I am wondering if this is the case too. Are we starting to pay for our three years of cooler weather with a vengeance?! Only time will tell but I'm really not liking 2011 so far weatherwise it has to be said!

[reef]

Another interesting stat is that if April can finish on 12.0C after adjustment then it will only require a May CET of 12.0C to make this the warmest spring on record.

Getting above average Mays hasnt been too difficult in recent years either!

[Optimus Prime]

Another interesting stat is that if April can finish on 12.0C after adjustment then it will only require a May CET of 12.0C to make this the warmest spring on record.

A done deal?

[Backtrack]

All I can add to this discussion is that records are made to be broken.

[The PIT]

We're plodding along at 11.3c another jump up today so the warmest ever here beating 2007. Spring rainfall so far is at 22.6mm but we will probably need it to keep dry well into May for our lower-est ever record to be broken which is 55.3mm in 1990.

[reef]

Hadley is on 11.6C to the 21st. Yesterday came in at an astonishing 15.6C.

Today's min is 9.3C and with maxima likely to be well into the 20s we could well be looking at a 16+C mean tomorrow.

[BornFromTheVoid]

The 06z GFS would have the CET around

11.8C to the 22nd

12.0C to the 24th

11.9C to the 26th

11.8C to the 28th

11.8C to the 29th

[The PIT]

Big bump for us up to 11.6c and that's not including today's temps. Some more hot days to come yet before a slight cool down. However I'm pretty confident we'll get anew record in Sheffield.

[Interitus]

I think those concerned with how warm this month may end up need to remember we have probably seen warmer 4 week periods coinciding with non calandar months and had these periods done so many other months would have registered much higher CET values. This year the warm synoptics have coincided perfectly with the calandar month - a rare feat.

Actually ten of the last eleven days of March were also at or above the long term April mean so the coincidence of synoptics with calendar month was not overly critical, emphasising how impressive this spell of weather has been.

Edited April 22, 2011 by Interitus

[Scorcher]

Actually ten of the last eleven days of March were also at or above the long term April mean so the coincidence of synoptics with calendar month was not overly critical, emphasising how impressive this spell of weather has been.

I agree the second half of March was also warm with some exceptionally warm sunny days- I seem to remember enjoying clear skies and 18C exactly a month ago today.

[damianslaw]

Actually ten of the last eleven days of March were also at or above the long term April mean so the coincidence of synoptics with calendar month was not overly critical, emphasising how impressive this spell of weather has been.

A very similiar timeframe to the cold spell of last Nov/Dec - which began around the 20th Nov - well it turned below average around then and the last week from the 24th was exceptionally below the norm. This spell I think will bear an uncanny resemblence to the cold spell in terms of duration ending as did the cold spell by the 26th - therefore I foresee much more average conditions. I am not buying the continued warm weather GFS is showing today - i feel heights will build strongly to the north to prevent any warm uppers from the south making renewed inroads.

Expect downgrades from GFS by Monday - remember what the models were like on christmas day many seemed to be on their holidays and only got to grips with the pattern change come the 27th - same thing is happening now with the easter hols, also remember the GFS does poor when it comes to scandi highs - ECM is much better.

[Kentish Kiwi]

A very similiar timeframe to the cold spell of last Nov/Dec - which began around the 20th Nov - well it turned below average around then and the last week from the 24th was exceptionally below the norm. This spell I think will bear an uncanny resemblence to the cold spell in terms of duration ending as did the cold spell by the 26th - therefore I foresee much more average conditions. I am not buying the continued warm weather GFS is showing today - i feel heights will build strongly to the north to prevent any warm uppers from the south making renewed inroads.

Expect downgrades from GFS by Monday - remember what the models were like on christmas day many seemed to be on their holidays and only got to grips with the pattern change come the 27th - same thing is happening now with the easter hols, also remember the GFS does poor when it comes to scandi highs - ECM is much better.

To be fair though, making assumptions of what the weather will be like April/May simply based off the pattern of what happened in December into January hardly has any real basis... Even if it does bear an 'uncanny resemblence' (something which I had also noted) doesn't mean everything's going to follow on in a similar pattern, in fact I would argue that it's more likely it wont.

I do however also get the feeling that we may see more of a predominance of heights to our north now that the Polar Vortex is disintegrating, at least for a period at the beginning of May and especially compared to what we have seen during the last few months.

[damianslaw]

To be fair though, making assumptions of what the weather will be like April/May simply based off the pattern of what happened in December into January hardly has any real basis... Even if it does bear an 'uncanny resemblence' (something which I had also noted) doesn't mean everything's going to follow on in a similar pattern, in fact I would argue that it's more likely it wont.

I do however also get the feeling that we may see more of a predominance of heights to our north now that the Polar Vortex is disintegrating, at least for a period at the beginning of May and especially compared to what we have seen during the last few months.

The polar vortex is long due a disintegration it has been unusual this year in how strong and long lasting in situ it has been. May is when northerlies and easterlies reach their yearly maxim, when the polar vortex on average is at its weakest and thus your belief that northern blocking will be much more in evidence from now on is very much a good one. Now is not the time for cylogenis over Greenland indeed southerly tracking lows are very much likely to show there hand, with a weak northern polar front jet and thus a much stronger southerly pfj something we haven't seen since December. We've been very lucky this April, had the polar vortex weakened in late March I suspect we would have had a very different outcome with strong northern blocking and a much colder northerly/easterly airstream.

[Weather-history]

February 1779 7.9c (4.1c above normal)

May 1833 15.1c (3.9c above normal) (second highest 1848 13.9c)

June 1846 18.2c (4.0c above normal)

Those months and the current one shows just how hard it is to get really large +ve anomalies. It is easier to get -ve anomalies of similiar size, although these are restricted to the winter months, than it is to get the +ve counterpart

Say April 2011 ends up as 12.0C, it will "only" be 4.1C above the 1961-90 average and yet it will well ahead in its rankings. December 2010 is the 2nd in its rankings but has an anomaly of -5.3C. An anomaly of +5.3C say for April would be a CET of about 13.2C

All of the greatest anomalies are -ve values and occurred during winter months.

[reef]

Hadley is on 11.8C to the 22nd. Yesterday was an exceptionally warm 16.5C, which is actually equal to the 1971-2000 average for July and the warmest April day since 16th April 1945 which reached 17.0C!

[Optimus Prime]

If it does come out at 12.1c the last ten years would have averaged 9.6c which beats the 1940s at 9.3c.

[Kentish Kiwi]

Hadley is on 11.8C to the 22nd. Yesterday was an exceptionally warm 16.5C, which is actually equal to the 1971-2000 average for July and the warmest April day since 16th April 1945 which reached 17.0C!

Is it possible today could be even warmer? Is there any risk of the mean CET record being broken?

[stewfox]

Those months and the current one shows just how hard it is to get really large +ve anomalies. It is easier to get -ve anomalies of similiar size, although these are restricted to the winter months, than it is to get the +ve counterpart

Say April 2011 ends up as 12.0C, it will "only" be 4.1C above the 1961-90 average and yet it will well ahead in its rankings. December 2010 is the 2nd in its rankings but has an anomaly of -5.3C. An anomaly of +5.3C say for April would be a CET of about 13.2C

All of the greatest anomalies are -ve values and occurred during winter months.

Why is that ?

Does heat not travel well ?

I suppose the variance isn't as great. We might hit 35c and Barcelona 42c. Yet if we max -5c that comes from Moscow max -20c etc ?

We don't get heat sources of 50c etc ???

[damianslaw]

Is it possible today could be even warmer? Is there any risk of the mean CET record being broken?

Maxima has been lower in central and northern england today compared to yesterday so I doubt today will record higher CET value.

I suspect the CET will peak tomorrow at 12 degrees possibly 12.1 degrees - thereafter it looks like being nudged back down slightly thanks in large part to some much cooler nights next week - I wouldn't bet on 12 degress being the finishing mark - a safer bet would be 11.8 degrees, by Friday and Saturday maxima could be struggling to reach low teens.

[reef]

Hadley is on 12.0C to the 23rd. Yesterday came in at 15.5C.

Today's min is 7.9C, so its likely we'll be a bit cooler than yesterday but we wont see much of a change in the figure.

[BornFromTheVoid]

A quick look through the 06z GFS, the CET should be around

12.0C to the 24th (13.1)

12.1C to the 25th (13.0)

12.0C to the 26th (10.2)

11.9C to the 27th (8.5)

11.7C to the 28th (8.3)

11.7C to the 29th (10.0)

11.7C to the 30th (11.6)

11.5C to 11.9C the most likely landing zone now I'd say.

[Backtrack]

So 11.8C was April 2007's record?

I would say that will be matched with an 11.8C this year. Can't see it been beaten unfortunately.

Edited April 24, 2011 by Jordan P