| typhoon_tip |
| (Meteorologist) |
| Tue Sep 04 2007 05:26 PM |
Re: 99L
|
Quote:
Question...
How far south do you think 99L will move?Is there any chance of a katrina like track.Right now i see it drifting SE.
It is impossible to say with any certainty...as you well know.
Possibilities, assuming this does succeed in developing, range from slow eastward component drift, to then resuming a north motion well-enough offshore to not be a significant impactor beyond surf, to eastward component drift, to then retrograding west (perhaps even after performing a loop) as a more serious eventual threat.
Most guidance show solutions at or in between these themes, but ALL develop this at this point in time. The NAM's 06z and 12z solutions blended together with the 00z CMC would spell some signficant trouble for New England.
One additional concern for me is that warm SST anomalies that are currently aligning along most of the Coastal waters and extending eastward to beyond 70W. The following link elaborately shows this, and some phenomenal sigma values along and the preceived path of this would-be system:
http://www.coaps.fsu.edu/~maue/sst2.png
The integrated heat content is obviously no especially high once we get N of the Gulf Stream recurving latitudes (roughly 37N), but the shelf waters have been as high as almost 80F -- even as far N as the New York bite waters:
Currently, we see they are not, but the 80F isotherm is abeam of the Del Marva latitudes and if a TC were to evolve with the ferocity of the CMC/NAM blend, it would have a healthy fuel source to considerably high latitude; then enters the concern for how quickly it is moving and if the shelf waters can have enough time to assert very important weakening in time. Bob is an example of this, as he was still deepening slightly even after crossing the gradient from the Gulf Stream to the shelf waters S of Long Island.
Confidence is high in the overall larger-scale synoptic evolution, and confidence is growing that there will indeed by a TC to monitor. To pick each concern apart:
NAO teleconnector has entered a period of upward rising values. That means the tendencies to lift the exit latitudes of the westerlies from off the N/A continent is present. Therefore, seeing the operational models converged on a ridge amplfication first along the Mid Atlantic and New England areas, then bulging seaward toward the east-northeast is increasingly plausible relative to this teleconnector signal. This also enhances the plausibility for trapping features in the regions surrounding 30N/70W.
TC: Currently NHC has advertised this as a non-tropical area of low pressure. I find that interesting because my own evaluation late last night had this as pretty well entered into a symmetric phase transition in terms of environmental conditions. The trouble is, shear I think is masking some of this. However, the frontalysis that was in that vicinity had completed by evening last night, such that DPs north to south across the axis of apparent cyclonic circulation had become homogenized. Nevertheless, whether it is or is not more or less tropical is probably less important at this hour. Shear continues to impact this and will continue to do so in the shorter terms. Once said ridge development gets underway, this will weaken this NW shear markedly and we'll see the deep layer field lurch rather abruptly into a more favorable regime. That will probably take place in the 30 hour time range and onwards. Until then, this will probably (but not certainly) remain a fledging interest with lots of modeling debate. The TCs best hope in surviving this first day or so of shear assault is to bodily move east-southeast such as to tap into a lower "relative" shear result. ...Ironically, a more important threat to the EC may require moving away...