April 2015 CET Forecasts

[BlueSkies_do_I_see]

I will happily lose the competition to see the first 12C.

[Daniel*]

I will happily lose the competition to see the first 12C.

Me and Craig would be happy I think it is achievable and more looking at models :-)

[Roger J Smith]

I agree with the 10.1 by 15th projection and would expect it to remain close to that value through maybe 19th on current GFS guidance, but looks quite cold after that, of course GFS 11-16 day is little more than a vague suggestion but if that model has any clue, the 10 to 10.5 level will be hard to maintain and could fall back into the low 9s. But take that as a model interpretation rather than a forecast. Maybe the cold signal will fade out before we get there.

[Roger J Smith]

So, back in post 95 I listed these 17 cases where first half of April achieved 10.0 or higher. These are the final values in each case, followed by the ranking overall ... looks fairly good for a 10.0+ finish just from the background random chances in this sample. Most of the counter-examples made it into the other table of cooling.

 

1778 _ 10.2 __  8.2 (t-140)

 

1783 _ 10.0 _ 10.1 (t-12)

 

1792 _ 10.2 _ 10.0 (t-15)

 

1798 _ 10.2 _ 10.4 (5)

 

1803 _ 10.2 __ 9.1 (t-61)

 

1826 _ 10.0 __ 8.5 (t-88)

 

1865 _ 10.0 _ 10.6 (3)

 

1869 _ 10.2 _ 10.1 (t-12)

 

1894 _ 10.4 __ 9.7 (t-28)

 

1926 _ 10.5 __ 9.3 (t-53)

 

1943 _ 10.5 _ 10.5 (4)

 

1945 _ 10.4 _ 10.1 (t-12)

 

1946 _ 10.0 __ 9.9 (t-22)

 

1995 _ 10.2 __ 9.1 (t-61)

 

2007 _ 10.1 _ 11.2 (2)

 

2011 _ 11.0 _ 11.8 (1)

 

2014 _ 10.1 _ 10.2 (t-7)

Edited April 10, 2015 by Roger J Smith

[Summer Sun]

9.3c to the 10th

 

2.7c above the 61 to 90 average

 

1.7c above the 81 to 10 average

[March Blizzard]

It's quite strange to think that we are currently around the same temperature as an average October, despite the warmth so far this April. In my head I think of October as a cool and wet month, yet a much above average and warm feeling April spell is only on a par.

Goes to show how much impact the longer days and stronger sun has on the perception of temperatures.

[richie3846]

However, October warmth often comes in the form of warm cloudy nights. Cool nights in April give way to warm sunny days (when we are lucky!).

[Summer Sun]

9.2c to the 11th

 

2.6c above the 61 to 90 average

 

1.6c above the 81 to 10 average

[DAVID SNOW]

I agree with the 10.1 by 15th projection and would expect it to remain close to that value through maybe 19th on current GFS guidance, but looks quite cold after that, of course GFS 11-16 day is little more than a vague suggestion but if that model has any clue, the 10 to 10.5 level will be hard to maintain and could fall back into the low 9s. But take that as a model interpretation rather than a forecast. Maybe the cold signal will fade out before we get there.

 

Looking almost certain now that temperatures after next weeks warm spell will drop back to average and below(imo)

[Roger J Smith]

I just looked at the latest GFS 12z run and estimated 10.6 by the 20th then falling back slightly in a more variable regime with one or two quite cold days indicated, finishing about 9.5 to 9.8.

 

However, trends beyond day eight on any global model can easily fade out and be replaced by different signals. Almost the entire field of forecasts have a chance of winning the month. But I would place my bets on those in the area between 9.0 and 10.5 at this point.

[Summer Sun]

9.2c to the 12th

 

2.5c above the 61 to 90 average

 

1.6c above the 81 to 10 average

[Summer Sun]

9.2c to the 13th

 

2.4c above the 61 to 90 average

 

1.6c above the 81 to 10 average

[BornFromTheVoid]

The minimum today is 6.9C while maxima look like climbing into the low 18s, so an increase to 9.4C is likely on tomorrows update.

 

After that, the 06z GFS has the CET at:

 

9.7C to the 15th (14.1)

9.8C to the 16th (11.3)

9.8C to the 17th (8.

9.7C to the 18th (8.5)

9.6C to the 19th (8.6)

9.6C to the 20th (9.7)

9.7C to the 21st (10.4)

9.7C to the 22nd (10.1)

9.6C to the 23rd (6.5)

 

Below is a graph showing (provided we are on 9.7C to the 18th) how the CET would pan out according to the final 12 days of every other year in the CET record. The maximum we would reach, should we follow 1740, 2006 or 2010, is 10.7C. The lowest, should we follow 1808, is 7.1C. The 95th percentile in red (to finish is the warmest 5%) is 10.3C, while the 5th percentile in blue (coldest 5%) would leave us around 8.2C. That 8.2C to 10.3C can be seen as the likely finishing range before corrections, with something truly exceptional required to take the CET outside of that range.

 

 

[Summer Sun]

9.4c to the 14th

 

2.5c above the 61 to 90 average

 

1.7c above the 81 to 10 average

[Summer Sun]

9.5c to the 15th

 

2.5c above the 61 to 90 average

 

1.8c above the 81 to 10 average

[BornFromTheVoid]

The minimum today is 6.1C while maxima look like getting close to 15C, so an increase to 9.6C is likely on tomorrows update.

After that the 06z GFS has the CET at:

 

9.5C to the 17th (8.

9.5C to the 18th (8.3)

9.4C to the 19th (7.9)

9.3C to the 20th (8.5)

9.3C to the 21st (9.4)

9.3C to the 22nd (9.4)

9.4C to the 23rd (9.7)

9.4C to the 24th (10.1)

9.3C to the 25th (7.9)

 

Below is a graph showing how the CET would pan out according to the final 12 days of every other year in the CET record. The result of the final 12 days finishing in the top 5% warmest is in red, with the 5% coldest in blue, and the total range from other years in grey. The green dashed line is the 06z GFS prediction, and the solid green is the actual CET so far.

 

[damianslaw]

Over half way and well yes a very mild first half to the month, and now a very tall order to record an average month overall. Whilst we are unlikely to see any rise in the CET over the days ahead, nor are we likely to see any sharp drop, a gradual cooling off is projected, but a good chance we could still end up in the 9's which will mean an appreciably above average month CET wise.

 

Must say I wasn't expecting such a turn out, quite surprised how things have panned out and there was little sign in late March. Once again our weather continues to surprise us. April is always the hardest month to predict, patterns can be very stubborn at this time of year and its always a fine line between cold and very mild.

 

Pity it isn't May, I like April but feel the current synoptics would be far more valuable if it was May.

[Summer Sun]

9.6c to the 16th

 

2.5c above the 61 to 90 average

 

1.9c above the 81 to 10 average

[March Blizzard]

Over half way and well yes a very mild first half to the month, and now a very tall order to record an average month overall. Whilst we are unlikely to see any rise in the CET over the days ahead, nor are we likely to see any sharp drop, a gradual cooling off is projected, but a good chance we could still end up in the 9's which will mean an appreciably above average month CET wise.

 

Must say I wasn't expecting such a turn out, quite surprised how things have panned out and there was little sign in late March. Once again our weather continues to surprise us. April is always the hardest month to predict, patterns can be very stubborn at this time of year and its always a fine line between cold and very mild.

 

Pity it isn't May, I like April but feel the current synoptics would be far more valuable if it was May.

 

Yeah, the BBC had my location averaging around 6.5C for the first 5 days or so of April, this was in late March. It probably is the biggest "pick 'em" month of the year; it's the first that can see genuine warmth on a consistent basis, yet it's also capable of wintry weather on occasion, and even sustained cool/cold weather. It's that time of the year when summer starts to throw out the first jabs, but winter can still land an uppercut.

Edited April 17, 2015 by March Blizzard

[Summer Sun]

9.6c to the 17th

 

2.4c above the 61 to 90 average

 

1.8c above the 81 to 10 average

[Summer Sun]

9.6c to the 18th

 

2.3c above the 61 to 90 average

 

1.8c above the 81 to 10 average

[Eugene]

Good to see you've added 81 to 10 average SS, very handy to compare it to 61 to 90.

[DAVID SNOW]

A slow decline of the CET looks likely(imo) to months end, perhaps 9 to 9.2 in the end?

[BlueSkies_do_I_see]

I think you are probably right about a slow decline, but not before Saturday.

[Summer Sun]

9.5c to the 19th

 

2.1c above the 61 to 90 average

 

1.7c above the 81 to 10 average

Edited April 20, 2015 by Summer Sun