typhoon_tip
(Meteorologist)
Fri Oct 28 2005 12:12 PM
Re: Beta...

Quote:

I believe it is becoming increasingly possible that the area of disturbed weather moving through the central Caribbean now may take the ball and run into the NW Caribbean and develop, whether as its own entity or merged system with TS Beta, and become a threat north of 20N. The trough moving across the lower Mississippi valley is digging quite far south into the western GOM and seems to be in a position to pull this disturbed area and TS Beta north/north-northwestward. Beta is beginning to move a bit further north at 4 knts, and is north of the model init positions. Don't know what may come of all this, and only the Canadien makes trouble for the CONUS, but it seems that a further north solution is quite possible. If its far enuf north, it could get into the Yucatan Channel as shown in the 12z NAM. Remember yesterday the models were too strong with the ridging in the SE US, and this allowed TS Beta to come further north. If the flow remains progressive (as shown by a number of models) then anything in the NW Caribbean early next week should find a seam in the ridge to make a northward run. On the other hand, if TS Beta makes the sharp left into Nicaragua, the disturbed area may develop on its own and move to the NW. Third, Beta may hold out long enuf before making the left turn to disrupt any development of the Central Caribbean disturbance, dissipate over Nic/Hon, and allow the remnant disturbance to dissipate in the westerlies. This may be last call (we Hope) for the 2005 season, as the longer range shows (GFS) less favorable conditions north of 20N, as the westerlies bring on Fall to the east. We'll watch and see, but the Caribbean still could be trouble for the CONUS next week. Hopefully this will shut the door on what has been historic and tragic hurricane season. Cheers!!




Careful ...last night I attempted to even hint at a N adjustment and I used a kind of tactical analysis of the BAM clusters (the biggest W motion cheerleaders of the band-wagon for days now...) and only HankFrank defended me - D'oh. Which is good, he's pretty damn bright about this stuff... Anyway, the short and skinny was that the BAMS is a llv intended use, which incorporates beta effects along with the advection field (hense the name)... The BAMM does the same, but for a deeper layer: mid-level through H850. Finally, the BAMD does so for upper level down to H850...

My issues were basically that...
a) Beta drift is more effectual on systems with bigger circumvellate (vorticity and torsional analysis is too complex so just state it as so...) and the storm "Beta" is a small circulation - though is growing in time.
b) I have a problem with relying on one camp (with Beta Effects) vs another without, alone, because obviously both apply vectors in this situation... Maybe that makes the argument a wash?

Anyway, it was just intended as an alternate way of analyzing this, and by coicidence, the worst forming model, LBAR was the biggest cheer-leader for a N pull (save the CMC for this context). Eh, not lending a much confidence... Now, hearing/seeing the NAM (the 2nd worst model for tropical events!) being N is....unfortunatley not doing much more to change the opinion... Maybe, finally, another more trustworth run will shift... Let's see: Nope... Again, only the LBAR and the CLIPER (12z) say N... Funny, they are verifying better on these positions this morning... And of course, the 00z CMC refuses to back off from striking Florida in a few days.. Yet, I suppose if we have to throw another entity (75W) into the fray....nothing is going to be correct!!

Still...Like HankFrank said and I agree... I can't get over the fact that after this trough lifts out that is currently over E N/A, heights should rebound near the Gulf somewhat, larger, lesser....

Oh, you want more headaches? Ok, well, a larger ridge response would impart a 'blocky' type regime and supply the (finally, phew) the W motion that everyone is just dying to see happen... While lesser would probably be negligibe in effecting anything but a slower motion. And, either form when looking at the global ensembles is very dern close to equally probablisitically weighted toward an occurrence. So, when you give mention to yesterdays models, some of those ensembles were actually weaker than the ridge that was verifying, so yes and no, but moreover, it has to be an uncertainty how this spatial evolution really plays a role in effecting storm (or storm"s") motion.

Anyway, I do agree on the interesting feature near 75W... Very interesting events down there to watch today!!



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