SomeLikeItHot

The experience with the scandi block last year was all models wanted to push low over the top rather than under, GFS being worse than ECM and UKMO for this, closer to the date they would tend to go under. Hopefully it will happen again.

+2.9 anomaly (81-10) Min today of 5.4 and max likely around 8.5 should stay on 7.2 tomorrow. Met office forecasts for 5 days . Then GFS 0z Ensemble mean. 9th 7.2 (7.0) 10th 7.0 (5.3) 11th 6.8 (4.8 ) 12th 6.5 (3.1) 13th 6.4 (5.5) 15th 6.0 +2.5 (61-90) +1.7 (81-10) 20th 5.0 +1.4 (61-90) 0.5 (81-10) 24rd 4.6 +0.9 (61-90) 0.1 (81-10) A less cold set of ensembles today, with the cold pushed later and less support.

What I thought the PV was in Chicago? So far a constant building of the heights both higher and further west towards iceland, which can only be a good thing. Will be interesting to see how the ensembles fall go today.

7.1 to the 6th +3.5 anomaly (61-90) +2.7 anomaly (81-10) Min today of 7.1 and max likely around 10.5 should rise to 7.2 tomorrow. Met office forecasts for 5 days . Then GFS 0z Ensemble mean. 8th 7.3 (8.8 ) 9th 7.3 (7.7) +3.7 (61-90) +3.0 (81-10) 10th 7.1 (5.3) 11th 6.9 (4.3) 12th 6.5 (2.7) 15th 5.5 +2.0 (61-90) +1.2 (81-10) 20th 4.1 +0.6 (61-90) -0.3 (81-10) 23rd 3.8 +0.2 (61-90) -0.7 (81-10) Marked switch to something much colder in the ensembles today as some convergence on a colder spell – GFS ensemble mean has some negative CET days around the 17-18th.

But we don't need 1 in 100 year event to get a potent cold spell especially at this time of year.

Does the UK get its cold weather from the West. No it gets it from the north and East. Certainly not a case of the weather moving across That said, it is possible that this piece of lore has some basis in the fact that it often occurs due to the similar circulation patterns eg. negative AO that can result in cold spilling into both regions.

6.8 to the 6th +3.3 anomaly (61-90) +2.4 anomaly (81-10) Min today of 6.8 and max likely around 10.0 should rise to 7.0 tomorrow. Met office forecasts for 5 days 7th 7.0 (8.4) 8th 7.2 (8.0) 9th 7.1 (6.8 ) 10th 6.9 (5.1) 11th 6.7 (4.3) +3.1 (61-90) +2.4 (81-10) 15th 5.9 +2.4 (61-90) +1.6 (81-10) 20th 4.8 +1.3 (61-90) +0.4 (81-10) 22nd 4.6 +1.0 (61-90) +0.01 (81-10) So Ensemble average trending to closer to average. Towards the later parts of the month. Likely however is that we will get something warmer or alternatively much colder than projected above as particularly in the later parts it’s a blend of two potentially very different outcomes.

6.8 again to the 6th. +3.3 (61-90) We are a whole degree colder than last year to the same date. I will try and do an ensemble estimate going forward later today if I get some time.

Good to see low pressure taking hold over southern Europe for the end of 6z run. Gives some hope that even if we don't get this bite of the cherry we are looking as a pattern change that makes a bit of decent cold more likley.

Cold air was pushing across most of the country on the 12th of Jan last year. If you look at the 12Z runs on the 6/1/2013 at +144 none of them had as cold air there as eventuated. ECM looked best for longer term cold but was too strong on high pressure to the north, UKMO was possibly closest but the high too far north and GFS had the high sinking south eastward letting the Atlantic in. None of them looked like lasting cold. If you look a few days later they are closer but all still show it ending quickly on most runs. FI is very short in these set ups it appears.

2nd best after the ECM, according to here

more of the same for the first 10 days but then I think a change to a much colder 2nd half. 3.5 for me.

Yes my method gives something slightly higher (6.5 to the 27th) - not being quite so cold on the 25/26th. Generally though the trend is stil to decline from here to around 6.1 - 6.2 by end of month.

After corrections its looking like it will be pretty close to that 9.5-9.6 boundary. So slightly above 61-90 and below other recent 30 year averages for the year.

6.9 to the 18th. +2.1 (61-90) +2.0 (81-10) Min today of 3.3 and max around 7.0 , tomorrow shold fall to 6.8 Met office forecasts for 5 days and GFS 0Z ensemble mean after gives. 19th 6.8 (5.2) 20th 6.7 (4.9) 21st 6.8 (8.7) 22nd 6.8 (6.0) 23rd 6.8 (6.6) +1.9 (61-90) + 2.0 (81-10) ... 25th 6.6 ... 30th 6.1 31st 6.0 +1.4 (61-90) & (81-10) So cooler end than a few days ago, but still trending to a well above average month. Likely range is probably 5.4 - 6.8, before corrections.

And set to go higher tomorrow. Been busy so I haven't done one of these for a while, but we have ensembles to the end of month now so: Min today of 6.5, and max likely around 12.0 Should see the CET rise to 7.1 tomorrow.After that it is likely to fall again for a while. Met ofice forecasts for 5 days and then GFS 6Z ensemble mean gives 16th 7.1 (9.3) +2.2 anomoly (61-90) +2.1 (81-10)17th 7.0 (4.8 )18th 6.9 (6.1)19th 6.8 (5.8 )20th 6.8 (4.9) 25th 6.6 +1.8 (61-90) +1.9 (81-10) 31st 6.3 +1.7 (61-90) & (81-10) So pretty much certain for a well above average month at this point.Possible range seems to be around (5.2 - 7.2)

+0.5 anomaly (81-10) Min today of 3.1 and max likely around 6.5 should fall to 6.2 tomorrow. Met office forecasts for 5 days 6th 6.2 (4.8 ) 7th 6.1 (5.9) 8th 6.4 (8.2) 9th 6.6 (8.3) 10th 6.5 (5.9) +1.6 (61-90) +1.2 (81-10) 15th 6.4 +1.4 (61-90) +1.3 (81-10) 20th 6.1 +1.3 (61-90) +1.3 (81-10) 21st 6.0 Warmer than average remains the trend for December. December CET needs to finish over 5.3 to beat 61-90 annual average for all 2013. Needs to be over 8 to beat 71-00 annual average. Needs to be over 11.5 to beat the 81-10 average. Needless to say the latter two are looking unlikely. Yes. They seem to have settled now on the current figures. Wether that means they will get larger revisions when they go to the official figues at end of month or not we will just have to wait and see.

6.7 to the 3rd +0.9 anomaly (61-90) -0.1 anomaly (81-10) Again they have revised the temps for the first two days, up this time. Not sure what is going on maybe tomorrow it will go down again! Min today of 4.5 and max likely around 8.0 should fall to 6.6 tomorrow. Met office forecasts for 5 days 4th 6.6 (6.2) 5th 6.4 (5.7) 6th 5.9 (3.3) 7th 5.8 (5.0) 8th 5.9 (6.7) 10th 6.1 +1.1 (61-90) +0.8 (81-10) 15th 5.9 +1.0 (61-90) +0.9 (81-10) 19th 5.8 +1.0 (61-90) +0.9 (81-10) So Ensemble average flipping around a bit, significantly warmer run this time along with the Met office changes.

6.1 to the 2nd +0.9 anomaly (61-90) -0.1 anomaly (81-10) Min today of 5.5 and max likely around 8.0 should rise to 6.3 tomorrow (much higher min than was forecast yesterday). Met office forecasts for 5 days and GFS 0z ensemble mean after that. 3rd 6.3 (6.8 ) 4th 6.1 (5.4) 5th 6.0 (5.3) 6th 5.6 (3.8 ) 7th 5.4 (4.0) 10th 4.9 -0.2 (61-90) -0.4 (81-10) 15th 4.2 17th 4.0 -0.9 (61-90) -0.9 (81-10) Marked cooler set of ensembles than yesterday. They changed the temps for the 1st so it droped to 5.7. One other thing to note is that there is a bit of a disconnect between the sorts of Temps the GFS is saying for the cross over between where I use the Met forecasts. GFS is 1-2 degrees lower than the Met.

On the brightside though GFS has gone from this. To This. In the space of three days! A big improvement if you don't live in scotland.

0.0 anomaly (81-10) Note: Strangely they list min yesterday as 2.2 and max as 8.8 so average should be 5.5 not 5.8. I expect to see at least one of these three numbers corrected at some point, below is on the basis of it being 5.8. Min today of 4.2 and max likely around 9.5 should rise to 6.2 tomorrow. Met office forecasts for 5 days + GFS 0z ensemble mean after gives. 2nd 6.2 (6.7) 3rd 5.8 (4.8 ) 4th 6.6 (5.2) 5th 5.6 (5.6) 6th 5.4 (4.3) 10th 4.8 -0.2 (61-90) -0.5 (81-10) 15th 4.9 17th 4.9 +0.4 (61-90) +0.4 (81-10) So trending above average. Worth noting that 81-10 average is less than 61-90 for december, due mostly to Dec 2010.

3.8 Cold but not entrenched cold, with some mild patches.

I agree 6.6 before corrections seems pretty much gaurrenteed at this point, so it all comes down to corrections to see where it ends up.

But the fun bit of the models is the 144 - 216 bit, where its not so far as to be completely speculative ala GFS +384, but plenty of run to run differences to keep it entertaining and lots to discuss.

Mass is irrelevant to orbit generally (gravitational force and inertia cancel), however if there is a break up and the fragments are moving apart each could have a differnet trajectory. Not hard to recaclulate though if they have a fix on its current position and velocity.