Good Morning everyone and a Happy New Year, First of all as a Newbie Poster although a lurker for a couple of years may I thank everyone, especially the experts for their very interesting posts at NetWeather. Apologies to the Moderators if I am posting the following in the incorrect thread, but I was a bit uncertain as to where I should place it. Please feel free to transfer it to where you consider it to be more appropriate. I have a few general questions for the more knowlegable members on how the weather models are produced. Yesterday's ECM 12Z was vastly different beyond T144 to their previous outputs as well as contemorary runs from those produced by other providers. Also the 18Z is often referred to as the Pub Run because of its ocassional eccentric output. Is the data for the 18Z, for example, imputted on a "clean canvass" as it were with information obtained from the previous 18Z output or is it added to the information provided from the previous 18Z run thus continuing from a possibly false premise?Or Is the data for the 18Z only entered from information gleaned from collection following on from the 12Z run as a running output as described above? Any information as to who the inputs are produced would be very much appreciated. Finally, As for example if last evening's ECM12Z looked to the ECM personnel to be for want of a better term "somewhat over progressive" do they have the opportunity to change things around with a few key strokes to produce a more reasoned output or is it a case of a bit like the Little Britain sketch in the travel agents with the "Computer Says No" and adoption of the old newspaper barons adage of "Print and be damned" and as a result whatever the computer shows is what is released for consumption? If anyone could shed light on this I would be most grateful. Heres looking forward to a cold and snowy January and hopefully February too. Kind Regards Dave