Wednesday, January 21, 2009

Model Comment from Art Douglas

I agree with your comments on the GFS and ECMWF tendencies over the past two years. I would add that in major pattern changes the ECMWF seems to do a better job in capturing that pattern change before the GFS finally switches. It appears now that the deep trof in the East will soon be replaced by a broad ridge in the Southeast. This pattern change is connected to the retrograding ridge in the Northwest that will be replaced by broad troughing along the Pacific Northwest Coast.

Until Sunday, the GFS was the model that was holding on to a very cold East while the ECMWF was starting to show the reversal with the building heights in the Southeast.Then the 12Z GFS on Sunday looked like last night's 0Z GFS run. Both runs had deep closed lows off California and a building ridge in the Southeast third of the country. This morning's new 12Z GFS has a closed low near Point Conception. As you point out the ECMWF has not been leaning this direction with a coastal system............but it suddenly changed last night with a deep trough down the California coast with similar 552 HTS near Point Conception (but not a closed low in any of the ECMWF ensembles). I bet the 12Z ECMWF will have some members with a closed low.

The current 12Z GFS and older 0Z ECMWF both have >0.50" in southeast AZ for the next 5 days and almost 1" on the Rim northwest of Phoenix. So the models are now converging and this time the GFS is the bold model per the pattern change. What happens on the plains is still a crap shoot given how far out it is.

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