April C.E.T

[Weather-history]

Since 1772, the first half of April colder than the second half of January

1804, 1824, 1828, 1834, 1837, 1846, 1916, 1924, 1967, 1968, 1970, 1975, 1983, 1990

Could happen again, this time around.

[johnholmes]

subsequent summers Kevin?

[Thundery wintry showers]

I'm not Kevin, but from what I remember of the post-1950 summers:

1967: mediocre for most, sunny June, unsettled July + August

1968: unusual summer, sunny June, then July & August were extremely dull wet towards the SE with some notable thunderstorms, sunny in N & W Scotland

1970: hot sunny June, cool cloudy July, fairly warm sunny August

1975: dry, notably sunny June with considerable contrasts, warm, fairly unsettled July, hot sunny thundery August

1983: cloudy June, exceptional hot July, dry sunny August

1990: cloudy June, sunny July, hot August with record early heatwave.

It's worth noting that each of the later 4 summers were generally sunnier than average.

[Duncan McAlister]

Looks very much like it could be down to 6.5C or lower by the 15th. After then is more uncertain, although any warm-up looks slow. The signs from the ensembles and operationals would suggest a below average month is the favourite.

[Glacier Point]

I'm not Kevin, but from what I remember of the post-1950 summers:

1967: mediocre for most, sunny June, unsettled July + August

1968: unusual summer, sunny June, then July & August were extremely dull wet towards the SE with some notable thunderstorms, sunny in N & W Scotland

1970: hot sunny June, cool cloudy July, fairly warm sunny August

1975: dry, notably sunny June with considerable contrasts, warm, fairly unsettled July, hot sunny thundery August

1983: cloudy June, exceptional hot July, dry sunny August

1990: cloudy June, sunny July, hot August with record early heatwave.

It's worth noting that each of the later 4 summers were generally sunnier than average.

Could be just conicidental (composites suggest otherwise) that the three La Nina years there - 1967, 1968 and 1975 - all had sunny Junes followed by less than spectacular Julys and mixed Augusts.

Current modelling is highly consistent with ENSO forcing. This leads me to think that May and June will switch us from winter to summer within a very short space of time, particularly with the current SSTA signal in the Atlantic at least supportive of an Azores type ridge displaced over the UK during the first part of the season.

Extended ECM ensembles confirm my impression that there will be a steady recovery towards the final third:

http://www.knmi.nl/exp/pluim/vijftiendaagse/index.html

so may be somewhere 7.5C to 8.5 would be an early guestimate.

Edited April 10, 2008 by Glacier Point

[Stu_London]

Could be just conicidental (composites suggest otherwise) that the three La Nina years there - 1967, 1968 and 1975 - all had sunny Junes followed by less than spectacular Julys and mixed Augusts.

Current modelling is highly consistent with ENSO forcing. This leads me to think that May and June will switch us from winter to summer within a very short space of time, particularly with the current SSTA signal in the Atlantic at least supportive of an Azores type ridge displaced over the UK during the first part of the season.

I tend to agree - i see a much warmer May (probably warmer than 2007) - it may affect the very end of April too

[Weather-history]

subsequent summers Kevin?

Interestingly, June 1846 is the warmest June on record whilst June 1916 is joint second coldest on record in that list.

1804 had a very warm June but July and August weren't as brilliant.

June 1828 was another warm June but a less than impressive July and August.

June 1834 was another warm June

June 1837 was another warm June

Summer 1924 was mediocre

Edited April 10, 2008 by Mr_Data

[kold weather]

I also wouldn't be too surprised if things warm up quite a bit at the end of the month but thats for another time and place I think.

Anyway now at 7C, only 0.5C below where we should be right now mind you!

Should stay around that mark now for the next 5 days I'd imagine, though there will be another drop today min given the CET averaged about 0-1C, max looks like being about 11C.

Edited April 10, 2008 by kold weather

[Thundery wintry showers]

Aye, but I think it may well drop a bit more in around 5 days' time looking at the recent trends in GFS/ECM, as the low drifts out into the North Sea introducing an Arctic northerly and the possibility of wintry showers.

The CET will probably lie in the 6.5-7.0 range for 1-15 April, but that doesn't rule out a warm-up near the end- it would only take a CET in the mid 9s for 16-30 April to bring it to average.

[damianslaw]

Can't see the CET coming in anything other than slightly above average at the most, any warm up not going to occur until the last few days. A below average CET at this early stage is very plausible, but it is very early days, much will depend on how cold next week gets, if it is an appreciably cold week, then even a warm up at the end may be too late to bring the CET up above average, may need a very warm spell to do this, but all very feasible still. All a far cry as others have stated from last year.

[johnholmes]

Interestingly, June 1846 is the warmest June on record whilst June 1916 is joint second coldest on record in that list.

1804 had a very warm June but July and August weren't as brilliant.

June 1828 was another warm June but a less than impressive July and August.

June 1834 was another warm June

June 1837 was another warm June

Summer 1924 was mediocre

sorry only just seen this, thanks for that kevin

hot or cold, seems about right for any prediction!

[BLAST FROM THE PAST]

Early summer warmth. Mid May and early June for main heat. All down hill from there as an early summer look. July will not be the holiday month

BFTP

[The PIT]

Aye, but I think it may well drop a bit more in around 5 days' time looking at the recent trends in GFS/ECM, as the low drifts out into the North Sea introducing an Arctic northerly and the possibility of wintry showers.

The CET will probably lie in the 6.5-7.0 range for 1-15 April, but that doesn't rule out a warm-up near the end- it would only take a CET in the mid 9s for 16-30 April to bring it to average.

Certainly a possibility with hints of it turning milder from the 18th. Of course these hints may return to continued cold hints.

[Stu_London]

Certainly a possibility with hints of it turning milder from the 18th. Of course these hints may return to continued cold hints.

Far too much ensemble and model disagreement to say anything other than it looks like another below average 7 days to come.

Beyond that is anyones guess

[Eugene]

Far too much ensemble and model disagreement to say anything other than it looks like another below average 7 days to come.

Beyond that is anyones guess

Completely agree stu, we shouldnt forget the runs were showing it turning milder with a southerly flow earlier this week for early next week but now it's a cold northerly flow initially with a cold high moving across us then moving east/northeastwards as shown on the ensembles, later next week needs to be sorted out first before the week after, a blocking high to our NE will confuse the models greatly as we all know.

[damianslaw]

Next 7 days definately below average or just about average CET, Monday and Tuesday are looking like cold days with widespread frost at night, so expect the CET to be at quite a low level by the middle of the month, yes signs longer term for an upward trend in the CET as would be expected, but still far too early to tell whether the CET will max out anything other than just slightly above average, which is what I feel the CET can only realistically only get too.

[Stu_London]

Hadley down to 7.1 to the 10th

Might make it to 7.0 to the 11th

today will be neutral or maybe even a small rise on the back of a milder night than of late.

Thereafter to the end of next week we are likely to see a slight falling pattern with the CET bottoming out around the 6.5C mark on the 17th or 18th.

Too much model uncertainty thereafter to be sure of anything, however to get to average (71-00) from the position I have stated would take a final 12 days of 10.55C - not impossible, but unlikely in my opinion.

The most likely landing point is somewhere 0.5C to 1c below the 71-00 average.

General probabilities as I see them are: -

Sub 6 - 2.5%

6-6.5 - 5%

6.5-7.0 - 12.5%

7.0-7.5 - 30%

7.5-8.0 - 35%

8.0-8.5 - 10%

8.5-9.0 - 9%

Above 9C - 1%

Quite a large spread at present, however this will shrink rapidly when the pattern after the 17th becomes clearer. Will update in about 4-5 days.

[Terminal Moraine]

Much as I'd like it remain cold for the rest of the month, I'd be very surprised if it happened as historical precedent shows it's an unusual event.

In the last 30 years the only Aprils which were consistently cold were 1978, 1989 and 2001, at least in this part of the country. In April 1989 we had max' temp's of 2.4c and 3.5c as late as the 23rd and 24th respectively and somehow I can't see a repeat of anything similar. I'm half expecting a gradual increase in temperature after the middle of next week with perhaps a few warm days towards the end of the month which will help blow my April CET prediction out of the water.

[Stu_London]

Much as I'd like it remain cold for the rest of the month, I'd be very surprised if it happened as historical precedent shows it's an unusual event.

In the last 30 years the only Aprils which were consistently cold were 1978, 1989 and 2001, at least in this part of the country. In April 1989 we had max' temp's of 2.4c and 3.5c as late as the 23rd and 24th respectively and somehow I can't see a repeat of anything similar. I'm half expecting a gradual increase in temperature after the middle of next week with perhaps a few warm days towards the end of the month which will help blow my April CET prediction out of the water.

Would tend to agree, which is why my projections show a 55% probability of gaining at least 1C in the last 12 days of the month.

[Stu_London]

6.8 or 6.9 on Manley* (waiting for front page to update) up to the 11th

Looks like it may have slightly decoupled from Hadley again which I expect to be around 7.1C

* courtesy of www.climate-uk.com

[Weather-history]

CET: (Apr 1-11): 6.9°C (-0.6 degC)

E&W Rain: (Apr 1-11): 15.6mm ( 68 per cent)

E&W Sun: (Apr 1-11): 62.0hr (119 per cent)

http://www.climate-uk.com/index.html

Its been the minima that has been keeping this April CET down more than the maxima and that has been the story of the last two months as well

Mean Min (1st-11th) 3.0ºC (-1.1 degC)

March

Mean Min (1st-31st) 2.7ºC ( -0.8 degC)

February

Mean Min (1st-29th) 1.2ºC (-0.6 degC)

February 1st - 11th April mean minimum: 2.1C (-0.8C)

Edited April 12, 2008 by Mr_Data

[Stu_London]

Hadley 7.0C to the 11th

[Eugene]

CET: (Apr 1-11): 6.9°C (-0.6 degC)

E&W Rain: (Apr 1-11): 15.6mm ( 68 per cent)

E&W Sun: (Apr 1-11): 62.0hr (119 per cent)

http://www.climate-uk.com/index.html

Its been the minima that has been keeping this April CET down more than the maxima and that has been the story of the last two months as well

Mean Min (1st-11th) 3.0ºC (-1.1 degC)

March

Mean Min (1st-31st) 2.7ºC ( -0.8 degC)

February

Mean Min (1st-29th) 1.2ºC (-0.6 degC)

February 1st - 11th April mean minimum: 2.1C (-0.8C)

Very interesting stats, thanks Mr Data.

Yes it's mostly mins keeping the CET down and the week ahead looks to continue this trend with some air frosts likely early to mid week could be quite harsh in places thats if the cloud clears, some troughs are forecasted to run down in a cold northerly flow monday and tuesday could be wintry on high ground and on lower ground in scotland.

[Snowly does it]

6.6 is the key this month for fans of cold CET returns - would be the first month in the noughties to fall 1.5 degrees below the 71-00 average - last time was Jan 97 (well, more correctly Dec 96 as you have to use 61-90 for pre-2000 and Jan 97 was within 1.5 of the 61-90 average)

[❄️❄️❄️❄️❄️❄️❄️❄️❄️]

Chance of April CET being below Jan CET?