September 2010 Cet

[BornFromTheVoid]

15.0C to the 2nd

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

Yesterdays max was quite a bit higher than I though at 21.4C, so yesterday's mean was 15.5C.

Minimum today is 10.6C and max temps look to be around 21C once again (GFS max and min temps have been too low lately) so we'll probably be around 15.3C by tomorrow.

[BornFromTheVoid]

15.3C to the 3rd.

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

Yesterday was 15.9C. Minimum for today is 9.7C, maxima look to be between 20-21C, so probably not much change by tomorrows update.

Going by the 06z GFS, looks like we'll be at 15.5C by the 6th, 15.4C by the 8th and back to 15.3C by the 10th.

[summer blizzard]

15.3C to the 3rd.

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

Yesterday was 15.9C. Minimum for today is 9.7C, maxima look to be between 20-21C, so probably not much change by tomorrows update.

Going by the 06z GFS, looks like we'll be at 15.5C by the 6th, 15.4C by the 8th and back to 15.3C by the 10th.

I am still happy with my previous thoughts of the CET being around the mid 14C's at the half way point, all models agree on a cool period around the 13th which should knock the CET back.

[BornFromTheVoid]

15.2C to the 4th

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

Yesterday was 14.8C after the max was 19.9C, lower than the GFS forecasted this time!

Minimum for today is 12.9C and maxima look around 18C, so and increase to 15.4C looks likely by tomorrow.

[Paul T]

15.4oc to the 5th -

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

Higher than the average in August.

[Thundery wintry showers]

True, but I think my 15.3C prediction is looking decidedly shaky for the following reasons:

• The first week has proved nothing like as warm as I expected. Despite southerly winds and high pressure, and regular GFS projections of maxima of 20-22C for most parts, the CET is running only slightly above the long-term average (bearing in mind that the average for the first week of September is more like 14.5-15.0).
  
• I built-in to my forecast that we'd see a mid-Atlantic ridge scenario but not until the last week of the month. Instead there's a high chance that it will arise a lot sooner than that.
  

Something near 14C looks pretty likely from where we're at now, IMHO.

[Milhouse]

If i was to predict at this early stage, i'd say that it will more likely end up above average than below. Theres nothing significantly cool on the horizon and with LP at the weekend bringing fairly warm days and mild nights i can see the CET remaining fairly static over the next week. Then all models indicate HP building from the south so nights may cool off depending on cloud amounts but daytime maxes remaining in the low 20s.

[BornFromTheVoid]

15.6C to the 6th

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

Yesterday was 16.9C. Minimum for today is 11.6 and the max looks to be just under 19C, so a small chance of dropping back to 15.5C if maxima can stay in the low 18s.

The GFS 06z would have us at 15.5C by the 9th, 15.6C by the 11th and 15.4C by the 13th. At this stage, I'd say somewhere between 15.2C and 15.7C by mid-month.

[Gavin P]

Those of us that went sub 14 need a potent second half northerly and a run of night time ground frosts to come to fruition. The models are flirting with this sort of scenario at the moment, so you never know.

[Stu_London]

I would have almost certainly gone considerably higher than my 13.4C had I been able to guess nearer the time and am now relying a run of days to come in at around 10C or less in the 2nd half of the month, a event that is quite rare, especially these days.

Hopes are pinned on the period just after mid month at present which has considerable ensemble support. Even if that does prove to be be a cold period, I am probably relying on the last part of the month to stay on the cold side just to get sub 14, let alone anywhere near my guess.

[BornFromTheVoid]

Provided we're at 15.5C by mid-month we only need to average 11.5C for the second half to reach 13.5C, which is ain't too difficult, especially if the mid atlantic block ridging to Greenland scenario comes off. Wouldn't be too difficult to get 15C days and nights around 4C under a slack Northerly airflow

Edited September 7, 2010 by NaDamantaSam

[Stu_London]

Provided we're at 15.5C by mid-month we only need to average 11.5C for the second half to reach 13.5C, which is ain't too difficult, especially if the mid atlantic block ridging to Greenland scenario comes off. Wouldn't be too difficult to get 15C days and nights around 4C under a slack Northerly airflow

In thoery correct, although only 16 sub 10C days in the last 20 Septembers (only 7 in the last 15) tells it's own story.

I think somewhere around 14.5c will be nearer the mark (but hope your scenerio plays out)

[Stu_London]

15.6C to the 7th

yesterday came in at 15.3C

last night was 9.7C, so a drop likely today.

15.6C sounds high but it is actually only 0.9C above the average for the first 7 days.

[BornFromTheVoid]

In thoery correct, although only 16 sub 10C days in the last 20 Septembers (only 7 in the last 15) tells it's own story.

I think somewhere around 14.5c will be nearer the mark (but hope your scenerio plays out)

Didn't realise sub 10C days in September we're so rare. The opportunity is there to change all that if the medium term of the 06z GFS comes off!

We could drop to 15.4C tomorrow if maxima stay at 19C or below today. The 06z would have us at about 15.3C by the 15th, so we'd need to average 12.1C for the 2nd half of the month to reach the 71-00 average, or 12.9C to reach my 14.1C guess!

[summer blizzard]

Didn't realise sub 10C days in September we're so rare. The opportunity is there to change all that if the medium term of the 06z GFS comes off!

We could drop to 15.4C tomorrow if maxima stay at 19C or below today. The 06z would have us at about 15.3C by the 15th, so we'd need to average 12.1C for the 2nd half of the month to reach the 71-00 average, or 12.9C to reach my 14.1C guess!

If the current model ouputs are correct then the second half of September 2010 will go down on record as significantly below average. GEM, GFS and ECWMF all agree on a pressure build in the Atlantic around the 15th with cool northerlies taking hold, GFS even has the upper isotherm below 0C late in the run.

I was a little twitchy early in the month regarding my average prediction however it looks like it could come to fruition.

[Milhouse]

15 days is a long day in weather terms. Just because something cooler is being hinted at just after mid month doesnt mean it will persist right through to the end of the month.

[summer blizzard]

15.5C to the 9th, however models are still insistant on a big change to cooler than average weather from the 15th.

[The watcher]

I'm afraid my 13.5c does now seem to be a tad low. I reckon it'll end up 14.2-14.5c.

[Paul T]

The minimum temperature in Plymouth last night was 16.5oC - thats pretty high for mid september!

http://www.plymouth.ac.uk/pages/view.asp?page=7708

Paul

[Stu_London]

The minimum temperature in Plymouth last night was 16.5oC - thats pretty high for mid september!

http://www.plymouth.ac.uk/pages/view.asp?page=7708

Paul

It is, although given sea temps are near their highest at this time of year and Plymouth's microclimate is hugely maritime influenced puts it into perspective a little.

Back on to CET, the scandi trough is starting to look very likely indeed which should mean a much colder second half of the month - whether we can get down below 14C remains to be seen but i expect to a few days between 10C and 12C from mid month which will be good enough to knock 0.2C to 0.3C per day off.

The final week will probably hold the key - it needs to stay below average for sub 14C to be a runner.

[summer blizzard]

15.5C to the 9th, however models are still insistant on a big change to cooler than average weather from the 15th.

CET is still at 15.5C, which is 1.8C above the full monthly average, though models are adamant on a massive drop from the 15th.

[summer blizzard]

Does anybody have the record date minima for the second half of September, the outlook looks very cool for the time of year.

[The PIT]

Mr Data will have however the massive drop has been delayed again although I have little faith in projected temps by the GFS as there's been some really odd ones that far out.

[Cymro]

Seems rather high compared to the actual weather we have been receiving? Surly this will start taking a drop in the next week and down from there providing what the models are projecting materializes?

[The PIT]

Seems rather high compared to the actual weather we have been receiving? Surly this will start taking a drop in the next week and down from there providing what the models are projecting materializes?

15.5 will be about as it's be rather warm for September so far.