April C.E.T

[The PIT]

If FI has anything to do with it it'll start rising rapidly after that. Lol. It'll be interesting to see how this cool spells lasts.

[reef]

Yesterday averaged 6.6C according to Hadley, meaning we're now at 9.7C:

http://hadobs.metoffice.com/hadcet/cet_info_mean.html

Thats a drop of 0.8C. I imagine we'll be in line for a drop as big after today.

[Stu_London]

Indeed and for the next 3-4 days also before it stablises around the 6.5 mark.

[summer blizzard]

http://www.climate-uk.com/graphs/200804.htm

I thought this would be an interesting link for many people, because we are over 1.5C above this time last year, so with the uncertainty after mid-month, we still should'nt rule out a very warm outcome.

[Stu_London]

http://www.climate-uk.com/graphs/200804.htm

I thought this would be an interesting link for many people, because we are over 1.5C above this time last year, so with the uncertainty after mid-month, we still should'nt rule out a very warm outcome.

Interesting, but unless the forecast is very wrong we will be at least 2C below within 5 days.

Obviously it can swing quite wildly (over 1C per day) in the first few days - as there is more and more base data these swings become less - changes of more than 0.2C per day are rare in the last week.

[Duncan McAlister]

http://www.climate-uk.com/graphs/200804.htm

I thought this would be an interesting link for many people, because we are over 1.5C above this time last year, so with the uncertainty after mid-month, we still should'nt rule out a very warm outcome.

Interesting that last April spent a fair amount of time hovering near the average, although I remember the nights were cool at first.

To take it to the other extreme, there is still a chance, however slim, that April could beat January's 6.6C for cold. Recent GFS and ECM runs would suggest it's possible. It would take a month 1.5 below the 1971-00 average, and March 2006 was 1.4C below, so there is recent precedent for such anomalies. For an April colder than 6.6C however, we have to go back to 1986.

[Guest Mike W]

April 1989 was the last time April had a colder CET than 6.6, it finished at 6.5. Sorry just to edit the fact5t hta it's 6.5 on the Manley version from Phillip Eden's web site. it's 6.6 on the Hadley Series.

Edited April 6, 2008 by Mike W

[Weather-history]

Looks like yesterday was the coldest daily April CET mean since probably April 1986.

Edited April 7, 2008 by Mr_Data

[eddie]

The Hadley CET is now 8.5C. Yesterday was a very cold 2.3C

To add some context, there have only been 83 April days since 1772 that have been colder out of over 7000. It's in the top 1.2% of cold April days.

[Snowly does it]

Fascinating. As the first 4 days were at almost record April levels you would have to say it was an exceptional mild spell. 2 days of the cold spell have decimated that and left us just 0.4 above the long term average and I expect tomorrows update to put it below, so a very exceptional cold spell?? I think the figure from Eddie says it all.

I wonder what a top 100 January coldest CET day would be? -4 or thereabouts? Very very cold.

[eddie]

I wonder what a top 100 January coldest CET day would be? -4 or thereabouts? Very very cold.

-4.9C would get you in the January top 100. We haven't had one of those since 13th Jan. 1987 (-6.6C!).

Edited April 7, 2008 by eddie

[Snowly does it]

-4.9C would get you in the January top 100. We haven't had one of those since 13th Jan. 1987 (-6.6C!).

Now THAT's cold! Puts yesterday into context nicely.

[Thundery wintry showers]

The Hadley CET is now 8.5C. Yesterday was a very cold 2.3C

To add some context, there have only been 83 April days since 1772 that have been colder out of over 7000. It's in the top 1.2% of cold April days.

Yes, it really was exceptional for the time of year.

Although, looking at it another way, that means we'd expect, on average, about 1 in 100 April days to be as cold, which as there are 30 days in April, would probably mean no less than a 1 in 5-10 year event (accounting for persistence of weather types such that we'd expect to get some Aprils with more than one similarly cold day, otherwise we'd be talking just once every few Aprils). In that sense it doesn't look quite as impressive on a long-term scale, though it remains very impressive given the warmer climate nowadays.

[kold weather]

I think for the time of year this cold shot has been close, if not in the exceptional cold bracket. The SE must have been rather close to its coldest CET max for a awful long time I'd have thought.

Still a 2.3C day CET would be pretty decent in winter...indeed to put it into even better context there was just ONE colder day in Jan 08!

Today should see another big drop though not as extreme as yesterday. I'd guess that todays CEt has come in somewhere between 4-5C and tomorrow will probably also come in around that mark I think.

[damianslaw]

4th-6th April 2008 has to go down as one of the most impressive switcharounds in recent years, from almost summer warmth to mid winter cold in the space of 2 days.

Yes the CET for yesterday puts the rest of winter to shame, the fact that we only recorded 1 day of lower value all winter shows how pathetic the winter was for true coldness - it also evidently shows how absent deep cold polar/arctic air has been all winter, but also how cold the arctic is at this time of year.

[Thundery wintry showers]

It also refutes the notion that northerlies can't produce significant cold and snow any more- I remember many were feeling along those lines, after two decidedly weak northerly incursions on 1-2 February and 3-4 March, which merely brought temperatures a degree or two below the long-term average over much of the UK mainland. This one, much later in the season, has produced colder temperatures than either of those two incursions.

Easter's was quite notable but I wouldn't say exceptional, there were similarly cold temperatures in late March in 1995, 1996, 2001 and 2006 for example (though it, too, beat the northerlies of 1-2 Feb and 3-4 March for potency), whereas I think this may well have been the most potent April cold snap since at least 1989.

[Stu_London]

Manley (www.climate-uk.com) now at 7.9C for the period to 7th April 2008. Still 0.5C above average for the first week in April

Bye bye to that after today.

Awaiting Hadley figs

[BLAST FROM THE PAST]

it also evidently shows how absent deep cold polar/arctic air has been all winter, but also how cold the arctic is at this time of year.

Only for us. Canada, Alaska, much of Siberia and China got the deep arctic cold. The set up kept the UK and Western Europe out of the loop.

BFTP

[Stu_London]

Awaiting Hadley figs

Down to 7.9 on Hadley - a fall of 0.6C

[Stu_London]

Another 0.5C knocked off the Manley figure (www.climate-uk.com) now down to 7.4C

Today will be a falling day also - temps in the zone generally 1 or 2 degrees below freezing and if the showers get going like yesterday, double figures will be hard to achieve in CET land, although the south east is predicted to be a little warmer and dryer.

I suspect we will stabilise mid to high 6s but another coldish shot is looking likely around the 16th which may drop it back down towards 6C. It's quite a long haul back to 8.1 (71-00 average) from there in the last third, although April is a month with a large range of possible temperatures, so some very warm weather in the final third could still make it an above average month, although i would rate the possibility at no more that 25%, even at this relatively early stage.

[Weather-history]

If from today, the rest of April had a daily CET mean of 11.2 (the overall CET of last April), then the CET for this April would end up as 10.2

[kold weather]

Well looks like we can just about rule out getting a +10C CET return for this month which is good I suppose.

I still wouldn't rule out above average yet as it would only take a 5 day SE airflow at the end of the month to push up the CET a good 1-1.3C but right now got to favor below average rather then above.

[Mr Sleet]

I think for the time of year this cold shot has been close, if not in the exceptional cold bracket. The SE must have been rather close to its coldest CET max for a awful long time I'd have thought.

Still a 2.3C day CET would be pretty decent in winter...indeed to put it into even better context there was just ONE colder day in Jan 08!

Today should see another big drop though not as extreme as yesterday. I'd guess that todays CEt has come in somewhere between 4-5C and tomorrow will probably also come in around that mark I think.

According to Beeb weather forecaster last night ( 10:30 pm), monday night/tuesday mornings' minimum was the coldest on record for (April) in the South West. No more detail added !

[eddie]

Hadley is now on 7.4C. Yesterday was a cool 4.0C.

Over 10C is now looking very unlikely indeed, not so much from a historic statistical point of view but because the models are not showing any real warmth in the reliable time frame.

Suprisingly, The April 2007 CET was only 8.4C by this point. The period 9th-30th April 2007 averaged 12.2C (rounded).

Edited April 9, 2008 by eddie

[Stu_London]

Manley (courtesy of www.climate-uk.com) is down to 7.0C - another drop of 0.4C - similar figures are expected for Hadley later.

Probably the last of the really sharp drops in the CET, although we remain slighlty below average so somewhere around 6.5C is likely by the 15th. A 3-4 day colder spell is looking increasingly likely at this time which may yet get us to 6.0C and whilst the last 10 days could see a rise of anything up to 2.0C - 2.5C, this would require conditions at the extreme end of possibilities and there is very little in the models to suggest that at present.

The main area of interest is whether we go sub 10C annually in running before the end of the month. For this we need to be 3.8C below the point of last year (very good chance of this happening before month end now!)