Regarding the Goofy BAMM/BAMD Runs Today

[wxman57]

I don't have much time - worked 5:30am-7pm today and hardly had time to take a break.

But I'm sure you all noticed the "weirdness" with the BAMM/BAMD models recently. Suddenly one or the other was taking Charley WNW into the middle of the Gulf and stalling it at day 5. Well, I thought about it and the reason is fairly clear.

The BAM models are not dynamic models. I.E., they basically look at the CURRENT mean flow at various levels (shallow, mid, deep), remove the storm circulation, and ASSUME that the general mean flow will prevail through the forecast period. That works good in the deep tropics where there are no fronts or deep upper trofs, and where things aren't changing much. But the BAM models do very poorly in the subtropics when the pattern is changing, like the fast-approaching deep upper trof and cold front into the Gulf. The BAM models don't really see that. They think there will be light easterly winds across the southern to central Gulf for the next 5 days. Thus the forecat for Charley to swim upstream to the central Gulf by the BAMD today.

Just goes to show you, you have to know the strengths/weaknesses of each model and not just follow one religiously.

[Stormcenter]

I don't have much time - worked 5:30am-7pm today and hardly had time to take a break.

But I'm sure you all noticed the "weirdness" with the BAMM/BAMD models recently. Suddenly one or the other was taking Charley WNW into the middle of the Gulf and stalling it at day 5. Well, I thought about it and the reason is fairly clear.

The BAM models are not dynamic models. I.E., they basically look at the CURRENT mean flow at various levels (shallow, mid, deep), remove the storm circulation, and ASSUME that the general mean flow will prevail through the forecast period. That works good in the deep tropics where there are no fronts or deep upper trofs, and where things aren't changing much. But the BAM models do very poorly in the subtropics when the pattern is changing, like the fast-approaching deep upper trof and cold front into the Gulf. The BAM models don't really see that. They think there will be light easterly winds across the southern to central Gulf for the next 5 days. Thus the forecat for Charley to swim upstream to the central Gulf by the BAMD today.

Just goes to show you, you have to know the strengths/weaknesses of each model and not just follow one religiously.

Whats' so goofy about that BAM models?

[bahamaswx]

Thanks for the explanation.