rwtwm

5.6c and 85mm please.

Two months in row I've gambled that we'll spend more time on the south side of an amplified jet stream than otherwise. I've learned my lesson. 6.5c and 127mm please.

Thanks Tamara, that's helped build my understanding. I do get that MJO is not a magic wand. My question is more around how I've seen people use MJO as a forecasting tool. I often see monthly composites posted with a single MJO phase assigned to a month. But If the speed of orbit is relevant then full month single phase composites can't be all that useful. On typing this, I think the gap in my knowledge is how those composites are actually produced.

A question if I may. It's not clear to me how this comment aligns with the use of full month composites when investigating the potential impact of MJO on our weather. If faster progression brings greater forcing, then shouldn't MJO 7 composites be different to MJO 6->7->8 composites for the same month?

Only the 15 degree spread at day 6 then. Maximum spread of near 25 degrees. Sometimes I think we'll be better served throwing dice.

A lot of people have been talking about the heights over the Arctic, but I've not noticed a great correlation between an AH and colder weather our side. This chart interests me though. The lows have been cut off over Newfoundland, and the runs that rebuild the block behind the low in the atlantic here have gone on to be the best for the holiday period. Let's see if that continues this evening.

What a mess. One of those horrible scenarios where the broad-scale pattern is easy to read, but the local impacts are impossible. The bifurcation of the suite makes it even harder, like a pencil standing on its end it could tip one way or the other, and thus end up on opposite sides of the table. The only thing we know is that it will fall.

I want to put my bemusement towards this chart on record, as a few others have done. My best guess is that it would be chilly to cold at the surface. At this point the pressure has been pretty slack over the country for a while. Some might ask why not just look at the t2m charts, but normally the z500s are ample to get a feel for the conditions. Here it's really like starting learning again.

I think you're advice on using ENS forecasts are useful, but I disagree with your central point. Looking at one DET run isn't very helpful, but across the different computers we have a 12 or so high resolution day 10 forecasts per day. If you look at all of them then you're getting the benefit of what is effectively a high res ensemble forecast. Yes it's not going to turn out exactly as one run predicts, but they are far more than just entertainment when used correctly. (This is an honestly held counterpoint, not an attack)

I know we saw some pretty good d8-9 charts in the last 24 hours, but isn't closer to Xmas/after Xmas more in line with the MJO progression? I'm less certain of this hitting, than I was with the November northerly. That said, if it does hit, even the 22nd seems early. Great to see the charts, but I can see this attempt getting moderated, and the next go being more successful.

You can see it coming on the 144 too. Lighter blues starting to show west of Greenland, and a negative tilt on the low behind.

Thanks for sharing these. P5 and P17 show the stellar outcomes of 24-36 hours ago. Even from the close up view though you get a feel that despite broad scale similarities, the local outcomes can vary dramatically even at day 6.

No if about it. We had a few easterlies in January this year, and they were cold without ever being bitter. With all eyes to the north-east I wonder if we might be sleeping on Thursday's event. Short ens posted above show the mean at around -6 even down this way. The low doesn't look particularly deep, but could be snow on the front.

I can see good reason to guess quite high or quite low, with nothing in between. After the last few runs, and the incessant amplification of the jet, I'm gambling on the cooler end. 3.6c please with 72mm rainfall. Btw, how does the scoring work in the contest? I've been doing these for half the year and haven't managed to cotton on.

I'm a bit of a novice with teleconnections, but I think that's basically what we're doing when we look at the MJO forecast. It tracks tropical activity around the world, and where that action occurs (and when) leads to different average conditions. Those are the composites you'll have seen posted. It's something I wish I knew more about from a predictive POV, but I am grateful to the more knowledgeable posters on here who do occasionally give us that insight.

That was a bewildering spell of model-watching. You could basically the cold spell down from 384 on the GFS. It's why I pay close attention in periods like this, when the op shows the same FI again and again. Even if those Ops are outliers to the ensemble.

Let's go for a notably chilly 5.7c please. With 81mm rainfall.

11.3c and 91mm please

Crikey the rain here right now is extraordinary. About half an hour of the heaviest rain I've seen all year at least. Thankfully this doesn't seem to be stalling, so hopefully no repeat of the flooding issues from a month or so ago.

Wow. Second's not bad for my first full season. Only downhill from here I think. Thanks very much to all those who keep this running.

15.0c and 61mm please. Honestly not confident with either forecast this month.

16.1C and 105mm please. A cool and wet start, and any high pressure later in the month will be nosing in from the west keeping it coolish.

You must have been just south of the deluge that caught us here. It moved through and joined up with the storm line. I've been anxiously checking the radar for the last hour as I have football this evening and typically cycle there and back. I don't think it's going to creep east but there's another line crossing Kent that may make the ride back a little miserable.

That's more of a shrug than the single cluster approach. One third each for each of the three standard UK options. I'm thinking tea leaves might be the way forward.

17.6c and 45mm please. I'm going to take the ECM extended at its word here. Mostly high pressure dominated, but occasionally slipping north and west to allow cooler spells. The occasional front toppling over the top.