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General Notes On GFS Checks


johnholmes

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Posted
  • Location: Sheffield South Yorkshire 160M Powering the Sheffield Shield
  • Weather Preferences: Any Extreme
  • Location: Sheffield South Yorkshire 160M Powering the Sheffield Shield
ADI AND JOHN your right.

I find working with more than one confuses me. There's so many. If you use more than 1 you get mixed up with time of runs and whats what.

<{POST_SNAPBACK}>

The confusing thing is which run is the right one to follow.

Follow the white rabbit.

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Posted
  • Location: just south of Doncaster, Sth Yorks
  • Location: just south of Doncaster, Sth Yorks

hi Pit

No one has the 'right' run; just follow the one you prefer but keep with it. Like I said in an earlier post, look at the other runs but stick with just one for trying to predict what is likely to happen.

regards

John

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Posted
  • Location: Wigan 259 ft ASL where it always rains
  • Weather Preferences: Hot Sun ,Snow and Cold
  • Location: Wigan 259 ft ASL where it always rains

If i follow the 06z for the 12th October, i'm looking at LP being a problem(Canary islands) , but if i follow the 12z then HP is the order of the day....which is the most reliable :D ????????????????

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Posted
  • Location: just south of Doncaster, Sth Yorks
  • Location: just south of Doncaster, Sth Yorks

like I've said before from T+144 its not bad and by T+120 usually pretty accurate, stop taking much notice of anything before then, whatever run it is.

regards

John

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Posted
  • Location: Sheffield South Yorkshire 160M Powering the Sheffield Shield
  • Weather Preferences: Any Extreme
  • Location: Sheffield South Yorkshire 160M Powering the Sheffield Shield

Quoting Paul

There were a selection of observations left out of the 12z run (probably to do with the hurricane in the US), which I guess could have had an effect...

So I gues I follow the later one.

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Posted
  • Location: Upper Tweeddale, Scottish Borders 240m ASL
  • Location: Upper Tweeddale, Scottish Borders 240m ASL

Roger - your discussion on energy patterns and mapping makes perfect sense. Thanks for sharing that - I have never really considered the global nature of systems - that are effectively 'peaks' of energy travelling round the globe west to east.

However, for the UK the critical consideration is the latitude of a system - and the positioning of the jet. The wobbles in the jet that make it move north or south mean either mild dreary weather, ot the possibility of polar incursions. Does your experimental modelling look at this?

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Posted
  • Location: Coventry,Warwickshire
  • Location: Coventry,Warwickshire

I am not really sure about the timing lines although it may work out.I guess here we are not looking at the short term forecast where we extrapolate from curent conditions or 3 months out where we can use Sea Surface temperatures and ice coverage to forecast, but in that mid range 1 to 6 weeks. Recent research shows that the linking between stratosphere and tropishere and the effects of planetary waves(Rossby) should make forecasting in this period far less random than one would believe. I guess this is why much of the most complex modelling done in GFS is to do with the atmospheric layers in the stratosphere. We do know that as a system moves over a large mountain range the atmosphere forms a waves and effectively breaks(like waves on a seashore) and I guess the timing of these waves and breaks and the time it takes for disturbances to rise up and then descend again through the Stratosphere is predictable. We ought to be able to make a pretty good forecast of the Jetstream and hence our weather from these factors.

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Posted
  • Location: Rossland BC Canada
  • Location: Rossland BC Canada

I don't want to disrupt this thread too much, so I will just say for now that answers to the above questions will be forthcoming under a separate title in this forum. I need to check a couple of things with the "powers that be" here before I start placing this material on-line on your site. The short answer to the latitude question is yes, the experimental modelling does create a grid of both "timing lines" and something I call meteo-latitude, since the system is not aligned exactly with the terrestrial lines of latitude and longitude, but adjusted to fit the earth's magnetic field. What that means for the UK is that systems at about 45N 40W would be expected to proceed to 10N 55W if all sectors in between were under similar conditions in the model's cause-and-effect parameters. In other words, the grid system that I use follows mean 500-mb flow patterns more or less. I think it might be a week or two before I even have a clear concept of what I want to post here on this research. The work is already out for peer review here and there, but I don't expect rapid results. This research does not boil down to some 8-page paper that somebody can read over a weekend and form an opinion right away. And being somewhat cynical about the acceptance thresh-hold for new ideas in the field, I would say that this opinion would be skewed towards the negative. Too bad temperatures in the UK in winter don't have the same bias, right? Or are there some hidden mild rampers out there? (I've got something for every kind of ramper in Santa's bag of goodies -- sorry, Father Christmas, whatever -- this is going to be the mother of all variable winters -- everyone will be claiming success for their forecasts unless they predict a long dreary stretch of near normal bland weather -- that is likely to bust).

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  • 11 months later...
Posted
  • Location: Leeds/Bradford border, 185 metres above sea level, around 600 feet
  • Location: Leeds/Bradford border, 185 metres above sea level, around 600 feet

Wow, this thread has been a fasinating read, it is also interesting to note that there was a 970mb low to the west of Ireland on the 27th.

Rrea00120051027.gif

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  • 2 years later...

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