| CoconutCandy |
| (User) |
| Thu Oct 01 2009 06:38 AM |
|
Re: Very active WestPac - Ketsana, TD #18 and more
|
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NOTE: This was Originally Posted to a NEW Thread ...
Very Active WestPac - Part Two - A 'Trio of Cyclones'
... but thought it Best to Post it Here as a REPLY ...
( Originally posted Tue Sep 29 2009 04:04 AM )
Also, Thanks to vpbob for posting to 'Other Storms'
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Yes Indeed. The Western Pacific continues to be VERY active, with a trio of developing tropical cyclones in the vicinity of the Mariana Islands.
A moderately active El Nino year continues in evidence with a VERY Warm Western Pacific Basin, which extends right across the International Dateline and well into the Central Pacific and beyond. Which of course translates into *plenty* of oceanic heat content for any cyclones that do develop.
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(Removed from this post is a discussion about the *STRENGTHENING* El Nino Event, which is now expected to persist well into the Northern Hemisphere Winter Season '09-'10.
El Nino Strengthens, Expected Well Into 2010
Please see my NEW post, (link above) for further discussions and a very illustrative animated graphic of SST's for the Eastern, Central and Western Pacific Storm Basins, clearly showing El Nino continuing to expand and grow over the past few months.)
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So we have, in dramatic evidence, a *huge* oceanic area with very high heat content, and when upper atmospheric conditions are conducive (omni-directionaly diffluent) you can usually expect cyclogenesis to occur. (Unlike the Atlantic basin this year, with it's prevalent strong uni-directional shear, effectively ripping apart many storms from developing.)
Indeed, such is the case today with a trio(!) of tropical cyclones developing near the Mariana Islands, all of which are expected to become named storms.
As vpbob21 made note of a day or so ago ...
Quote:
Quote from vpbob21 ...
While tropical cyclone activity is pretty much nil in the Atlantic basin, the western Pacific is really percolating with two active systems currently, and maybe more on the way.
... T.D. #18, about 675 miles ESE of Guam. This system is fighting easterly shear which has exposed the LLCC, but is expected to encounter better conditions and slowly intensify as it moves WNW. It is expected to pass very close to Guam as a mid-range tropical storm in about 2 days. The subtropical ridge is expected to hold and build westward. So this system could be a major threat to areas farther west in time.
On top of that there is a very healthy looking invest (99W) south of the Northern Marianas at about 10/145, that could well be classified shortly. Also another invest (90W) to the east of Kosrae is showing signs of organization as well.
All in all it figures to be a very active week or two for areas around the Western Pacific basin. Stay tuned.
As always, additional info on these cyclones can be found on the ...
Navy Research Lab (NRL) Tropical Cyclone Homepage
... and a terrific Color-Enhanced IR Animated Loop displaying the latest activity is at ...
http://www.goes.noaa.gov/guam/guamloops/guamircolor.html
(I like to click 'ROCK' for a back-and-forth motion and speed it up slightly. You can also click the 'ZOOM' button to zoom in repeatedly and while zoomed in you can click-and-drag to pan around.)
And in the following graphic, you can see the "Dueling Depressions", namely TD 18W and TD 20W as they both move WNW towards the Mariana Islands.
It's interesting to note that a day or so ago, TD 18W (just then classified) looked to be very healthy and robust, while some distance to the ESE was also a healthy looking disturbance, though still Invest 99W, not yet a depression. Meanwhile, the system that was to become TS 'Parma' was just a small, crescent-shaped area of convection due south of Guam, as vpbob noted above, which has become the first named storm of the three.
However, in the day or so since then, TD 18W has apparently weakened, while Invest 99W (recently upgraded to TS 'Melor') appeared to 'steal away the thunder' from 18W and has steadily organized, expanded in size and quickly strengthened to become a tropical storm. Latest Doppler Radar out of Guam shows 18W to be very weak and looking more and more disorganized by the hour. It just goes to show that things can change in a hurry in the tropics from one day to the next!
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Tropical Storm PARMA
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From a recent microwave satellite overpass of tropical storm 'Parma', you can already see a nascent eye-like ring of intense convection occuring in the inner core convection, that appears to be not quite aligned yet with the developing low-level circulation, as shown by light blue concentric circles.
In other words, (at least to my partially trained eyes!) I don't believe the storm has aligned itself vertically quite yet, or what is sometimes called 'the vertically aligned column'.
The LLCC seems to be lagging a short distance to the SE, perhaps due to a bit of shear coming from that direction, which would tend to 'lean' the upper portion of the storm in the direction the shear is blowing towards. But all that can, of course, change in a hurry as this tropical storm is expected to develop into a typhoon within a few days.