typhoon_tip
(Meteorologist)
Wed Jul 09 2008 04:28 AM
Re: Major Hurricane Bertha Now Moving Northwest

Quote:

You've all made some great points about Bertha's motion and intensity forecasting issues. Lois brings to light one problem that I've been thinking of as well, how most of these models aren't handling Bertha's intensity fluctuations at initiation very well. Another thing that has bothered me, which maybe someone else can explain further, is that over the past 2-3 days the official guidance has closely followed the CLIPER model. CLIPER is one of the lowest skilled models and for the official forecast and most of the model consensus to become aligned with the CLIPER seemed fishy to me, may just be this particular storm and its environment, or it may mean the models just haven't gotten a good grasp on Bertha (strength, size, motion, etc.). We'll see if the slight westward shift in the model consensus occurs in the 12Z run in the morning, perhaps the CLIPER will begin to be more of an outlier (like it should be), or perhaps since the steering currents will become so weak that model flip-flopping will become more of a normal occurrence (and the CLIPER may be the best choice - a.k.a climatology and persistence...). Enjoy reading everyones comments, thanks for any specific replies.




I would like to comment on the Clipper model but unfortunately, can't. I do not normally use that tool; so I don't really have a handle on its known biases, thus, how to balance its solutions against the back-drop synoptics/other model solutions - which may and probably do have their own biases.

I will say that the TPC has intimated a couple of times that "meandering" was a concern in track guidance, for having weakening steering fields/intensity fluctuations. This seems reasonable and we are probably needing more time along these late evening behaviors, to determine how important they are.



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