| typhoon_tip |
| (Meteorologist) |
| Mon Oct 17 2005 08:17 PM |
Re: Tropical Storm Wilma Forms in the Western Caribbean
|
Quote:
You'd almost expect the coldest tops in IR (the cirrus debris you mention) to move in an anticyclonic fashion, being up near the outflow layer and all with a ridge of high pressure aloft above the storm. That's nothing unexpected or detrimental to the storm. There are some nice low-level outflow boundaries on the north & northeast sides of the storm right now, evidenced on visible imagery, with some gravity waves in the midst of the convection removed to the NE of the storm. Pretty cool to see on vis, even if they are a little hard to pick out from time to time.
Do expect that the center is reforming a bit further south & southeast right now, continuing a trend I've been watching the past few hours on satellite imagery. The warm area developing on IR imagery is just south of where I'd place the center; what appears to be some mid-level dry air is becoming entrained on the west & side quadrants of the storm, somewhat separating the large mass of convection (feeder band) to the south from the main core of the system. Impacts on intensity in the short-term? To be determined...need recon down there to tell us where it's at now strength-wise.
Right; I too do not really see where the anticyclonic curl, whether centered in situ Wilma or not, would really serve as detriment.. But it is odd...perhaps a little to see skewness..
I do however see that as a fascinating behavior nonetheless.. I'm also interested in the asymetry of this as a whole. Folks on here have given mention to shearing in the environment but I don't find or see a source based on either my own interprative analysis of available sat, nor based on anything mentioned from HPC. It seems to be this is entirely perturbationally driven by nuances involved with the convection it's self.; maybe dry air involvement as well.
I also took note of the dry air entrainment issue as you say; in fact, there is a large envelopment of dry air that is pretty much butted up against Wilma's general arena of genisis - NW. It will be interesting to see how well she fends this off... As she deepens, she'll be more able to incorporate these drier values by extending her pgf outward, and I suggest that is why you see these initial incursion that you mentioned. Her presentation during the afternoon has overall improved; likely portending a deeper surface pressure and greater ingest pulling in the dry air in question... (5pm may confirm this) This could be a problem for rapid intensification enthusiasts, that she gulps dry air in intervals - but then again, HPC likes the SHIPs compromise over the dreaded GFDL anyway. Of course, passed behavior has demonstrated that sometime dry air on the perimeters fools everyone by becoming less an issue with intensity- a.k.a. Rita. ...Though didn't she subcumb a little bit... She did seem to max out prior to bumping into dry air over the western Gulf - haven't read any follow-up steady on her intensity curve...
Anywho...awesome to see those details in the vis. This has been a great day for observing g-wave phenom, as well as the the outflow, surface and aloft, as well as differentiating cloud structures.... totally cool!
I also agree with the center jump hypothesis.. I mentioned this earlier this morning I believed; the concern at the time being that with such limited convection in the N sector (pretty much as a whole) the circulation field would almost have to repond to where the persistent ascending air was distributed... No trouble believing that, being that it is consistent with understanding.
Lastly...tough to say for sure but I'm suspecting that the diurnal min is about at its vertex for the day.. I'm wondering if the last 3 hours denegration of activity is related to that?