S/E model bias with tracks of major storms…

[stormguy80]

In recent years, I have really noticed that the models tend to have a south and east bias with the track of major systems. It seems this would be most likely due to the models not being able to accurately replicate all of the positive feedback mechanisms (latent heat release, etc) associated with rapid cyclogeneses but does anyone have any additional insight into this? It seems to be a fairly consistent bias and most major busts with east coast storms in the past 10-20 years have occurred because of it (march ‘01 and late Jan ‘00 storm being the most notable ones). Interestingly though, with weak stable waves riding along an arctic boundary the models seem to have the opposite bias in that they take the track too far to the left.

[Ellinwood]

And we welcome you to "Stuff that was figured out back in the 90s." Sorry, but that trend is widely known.

Here's a page you should get familiar with: http://www.hpc.ncep.noaa.gov/mdlbias/biastext.shtml

[stormguy80]

Yes, I'm aware of this page but for a lot of the models there is no info there. Anyway, I have also been aware of this trend for sometime. I was more interested if anyone had any additional insight as to why this occurs although as I said, it's probably just that the models can't accurately simulate all the rapid positive feedback processes that occur with rapid storm development. If this trend is so widely known though, why do so many mets still get suckered into a more south/east solution? 2-3 days before the dec 26 storm everyone was writing it off saying it was going to miss most of the east coast. To a lesser degree the same thing happened with the Jan 12 storm. 1-2 days out everyone was saying it would pass S/E of Nantucket even though some of the guidance was already hinting that it would come farther west and pass over the Cape. NWS had the rain/snow line not budging any farther N/W than the Cape even though it ended up coming up almost to Boston with the more western track...

And we welcome you to "Stuff that was figured out back in the 90s." Sorry, but that trend is widely known.

Here's a page you should get familiar with: http://www.hpc.ncep..../biastext.shtml

[Ellinwood]

Yes, I'm aware of this page but for a lot of the models there is no info there. Anyway, I have also been aware of this trend for sometime. I was more interested if anyone had any additional insight as to why this occurs although as I said, it's probably just that the models can't accurately simulate all the rapid positive feedback processes that occur with rapid storm development. If this trend is so widely known though, why do so many mets still get suckered into a more south/east solution? 2-3 days before the dec 26 storm everyone was writing it off saying it was going to miss most of the east coast. To a lesser degree the same thing happened with the Jan 12 storm. 1-2 days out everyone was saying it would pass S/E of Nantucket even though some of the guidance was already hinting that it would come farther west and pass over the Cape. NWS had the rain/snow line not budging any farther N/W than the Cape even though it ended up coming up almost to Boston with the more western track...

Most mets don't get suckered by it. This year has also been quite strange, and you could see why the call was for more out-to-sea by reading the discussions more thoroughly. I'm sure dtk and/or others could give you some better specifics.