I am not in the least bit trolling. I am trying to keep a realistic head on that's all and the fact remains that the charts are not offering much cheer. That's all I'm saying. If I am wrong come the end of December I will gladly put my hands in the air to be shot at because I accept what I am saying is not what the masses want to see.
Just adding a touch of realism. It's no different really to those that are posting hope cast charts of one cool ish north westerly 15 days away.
Sorry if it is considered trolling but I am honestly not. I will refrain from further "mild" comments if it upsets people but equally I won't ramp up any phantom cold snap either.

---

OK folks, here's the deal. From now on, any WIO-type posts, especially any that do not make any reference to the model output available, will be deleted without any further warning. Such posting adds nothing to the quality of the discussion in this thread and in my experience just ends up being a darn nuisance.

Hope the above is clear.

---

 

Good question Neil!

The MetO updates in themselves have altered at least a couple of times in the past week. For a few days at the end of last week they mentioned about the possibility of a colder & drier spell later in December, and only yesterday the 16-30 day update mentioned that there was quite a lot of uncertainty wrt late December. I would find it hard to imagine that they could go from being somewhat unsure yesterday to being 100% sure today.

I must say I'm starting to get somewhat tired of these posts in which some seem to speak as if they have some kind of a crystal ball. Now I read that January is likely to be a write-off as well. What are some people, Mystic Meg?

That's why I thought, a bit of a change around ??

---

 

Good question Neil!

The MetO updates in themselves have altered at least a couple of times in the past week. For a few days at the end of last week they mentioned about the possibility of a colder & drier spell later in December, and only yesterday the 16-30 day update mentioned that there was quite a lot of uncertainty wrt late December. I would find it hard to imagine that they could go from being somewhat unsure yesterday to being 100% sure today.

I must say I'm starting to get somewhat tired of these posts in which some seem to speak as if they have some kind of a crystal ball. Now I read that January is likely to be a write-off as well. What are some people, Mystic Meg?

Sorry David I'm not trying to be mystic Meg at all. ☺But in lieu of me not producing an LRF this year I am just commenting on what I see. Particularly the background signals that at least HINT we have a long wait ahead of us.

I won't write off winter just yet of course I won't. But it cannot be argued we are in a pretty desperate place at the moment if only for the sake of our poor families from the north west. It has been truly horrific for them. Now that IS a reason to be downbeat. 

---

Sorry David I'm not trying to be mystic Meg at all. ☺But in lieu of me not producing an LRF this year I am just commenting on what I see. Particularly the background signals that at least HINT we have a long wait ahead of us.

I won't write off winter just yet of course I won't. But it cannot be argued we are in a pretty desperate place at the moment if only for the sake of our poor families from the north west. It has been truly horrific for them. Now that IS a reason to be downbeat. 

Agreed.

Let's all hope that sometime soon, the models do give us a bit of cheer. Even if it is only for a change to drier weather if not particularly cold, for the sake of those poor folks hit by the floods more than anyone else's.

---

I don't think anyone should fall into the trap of taking today's model runs as gospel in terms of what will happen in the lead up to Christmas. The setup from the weekend onwards doesn't look straightforward to me and there is likely to be quite a few twists and turns in the models over the coming days. A tweak here and there could influence greatly what's likely further down the line.

---

Back to the models: One can only come to the conclusion in view of today's general output, that the GFS 06z and 12z runs from yesterday were both major outliers.

---

Back to the models: One can only come to the conclusion in view of today's general output, that the GFS 06z and 12z runs from yesterday were both major outliers.

Things look grim when I posts a downbeat post like the one in the moaning thread, still I still believe that Shannon entropy is alive and kicking so all is not lost just yet.🙈

 Good point that always happens with very cold or warm runs happen Matt also thinks things are uncertain

https://twitter.com/MattHugo81

 

Sometimes it does not go a miss to remind ourselves we are here for the love of model watching and not always for the love of our particular weather choice because theres nothing we can do about it anyway

 

I don't think anyone should fall into the trap of taking today's model runs as gospel in terms of what will happen in the lead up to Christmas. The setup from the weekend onwards doesn't look straightforward to me and there is likely to be quite a few twists and turns in the models over the coming days. A tweak here and there could influence greatly what's likely further down the line.

 Good point that always happens with very cold or warm runs happen Matt also thinks things are uncertain

https://twitter.com/MattHugo81

 

Just out of interest what is so special about the forecasts at the top of the model? The verification stats show little difference between 500 and 250, so it's a reasonable assumption that at 10 they're only marginally more reliable. On top of that people using the top levels are generally making a further extrapolation about what could happen a further x number of days down the line. Basically they're making a forecast based on a forecast. The reason I ask this is because I saw a tweet showing top level warming at GFS+348 hours and the accompanying suggestion was this was positive if you want cold weather. How is that demonstrably better than posting a 348 hours 500hPa chart showing cold (or mild for that matter) and which would widely be dismissed as FI or JFF? 

---

 

Just out of interest what is so special about the forecasts at the top of the model? The verification stats show little difference between 500 and 250, so it's a reasonable assumption that at 10 they're only marginally more reliable. On top of that people using the top levels are generally making a further extrapolation about what could happen a further x number of days down the line. Basically they're making a forecast based on a forecast. The reason I ask this is because I saw a tweet showing top level warming at GFS+348 hours and the accompanying suggestion was this was positive if you want cold weather. How is that demonstrably better than posting a 348 hours 500hPa chart showing cold (or mild for that matter) and which would widely be dismissed as FI or JFF? 

Its a good point and like any other model output it needs to move into the more reliable timeframe before we even consider it.

Some worrying rainfall amounts of the GFS 12z by 144hrs

 

 

The GFS keep hinting at a lot of heavy rainfall for Wales, The Midlands and Northern England over the weekend and into the start of next week.

---

The rain is very worrying I agree. Also some really mild stuff on the GFS12z mid term:

---

In the strat any outcome very roughly like the one modelled looks like a successful forecast, while down here at the surface you need way more precision to get the weather to verify.

Basically a few hundred miles, a few degrees celsius and a few days either way in the strat makes no immediate difference to us. If it results in differing weather at the surface, we just say the strat forecast was correct, but the pieces didn't fall into place for us.

So I suppose strat forecasts are useful as a rough check on whether the effects modelled at the surface from the same data and the same equations are plausible or not.

---

 

Just out of interest what is so special about the forecasts at the top of the model? The verification stats show little difference between 500 and 250, so it's a reasonable assumption that at 10 they're only marginally more reliable. On top of that people using the top levels are generally making a further extrapolation about what could happen a further x number of days down the line. Basically they're making a forecast based on a forecast. The reason I ask this is because I saw a tweet showing top level warming at GFS+348 hours and the accompanying suggestion was this was positive if you want cold weather. How is that demonstrably better than posting a 348 hours 500hPa chart showing cold (or mild for that matter) and which would widely be dismissed as FI or JFF? 

If we are talking about Strat forecasts, they are very deterministic and a lot more reliable than other types of forecasts.

---

 

If we are talking about Strat forecasts, they are very deterministic and a lot more reliable than other types of forecasts.

No they aren't! That's the point I've just made. The verification stats for the GFS show the big win is at the 500hPa level over the 1000hPa one as you'd expect. Go up to 250hPa and there's next to no difference to 500hPa. As I said, if you go up to 10hPa I think you'd find the gains are very marginal indeed. On top of this people then use the 10hPa charts at +384 hours and say something like..."and 3 weeks after this we're likely to be in the freezer".

500 verification
http://www.emc.ncep.noaa.gov/gmb/STATS_vsdb/allmodel/daily/cor/cor_day10_HGT_P500_G2NHX.png

250 verification
http://www.emc.ncep.noaa.gov/gmb/STATS_vsdb/allmodel/daily/cor/cor_day10_HGT_P250_G2NHX.png

---

 

If we are talking about Strat forecasts, they are very deterministic and a lot more reliable than other types of forecasts.

But aren't they just another picture from exactly the same runs, with the same numbers and equations, as those which give us our standard tropospheric maps?

---

No they aren't! That's the point I've just made. The verification stats for the GFS show the big win is at the 500hPa level over the 1000hPa one as you'd expect. Go up to 250hPa and there's next to no difference to 500hPa. As I said, if you go up to 10hPa I think you'd find the gains are very marginal indeed. On top of this people then use the 10hPa charts at +384 hours and say something like..."and 3 weeks after this we're likely to be in the freezer"

Put it another way - a week ago some noteable warming at 1hPa started to be shown on the GFS charts at 384. It's still there at 216 on today's chart and it's been there every run (4 a day) for the past week.

http://www.instantweathermaps.com/GFS-php/showmap-strat.php?run=2015120912&var=TMP&lev=1mb&hour=216

In the meantime, the operational at both 500 and 1000 has shown all manner of outcomes at the same timescale.

It's been my experience that strat forecasting is actually pretty darned good... but our understanding of exactly what effects it'll have lower down still needs working on!

---

Frustration at 144 hrs, as both the GFS and the UKMO suggest an undercutting low:

http://www.meteociel.fr/modeles/gfse_cartes.php?&ech=144&mode=0

http://www.meteociel.fr/modeles/ukmo2.php?nh=0&ech=144&carte=1021

Just doesn't happen though 24 hrs later on the GFS.

http://www.meteociel.fr/modeles/gfse_cartes.php?&ech=168&mode=0

Who knows whether the UKMO might have been more promising?

---