Southern Hemisphere: Invest Thread 2009

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I've managed to sneak some net time,

[Somerset Squall]

I've managed to sneak some net time,

Good good!

South Indian Ocean:

97S is still persisting in the middle south Indian Ocean. Convection is currently being sheared to the southeast of the well defined LLC, but overall organisation of the system has improved over the last 24hrs, with convection being maintained to the south of the LLC by some good poleward outflow. This outflow has also tightened up the LLC which has been weak and elongated up until now. JTWC have become interested in the system once more, giving it a poor chance of development in the next 24hrs, mainly due to the high shear. This invest has persisted since March 1st, and only now does it look remotely like anything that may strengthen into a tropical cyclone over the coming days. It will not succeed in doing this however, unless that shear lets up.

South Pacific:

No invests.

[Somerset Squall]

South Indian Ocean:

Convection has been flaring closer to the centre of 97S this afternoon, as shear is easing over the system. Waters remain warm and outflow good so the LLC has been tightening up. If shear remains low, we could see a TC form in the next few days. JTWC have upgraded 97S' chances of TC development in the next 24hrs to fair based on the improved envionment and well defined LLC.

South Pacific:

No invests.

Edited March 8, 2009 by Somerset Squall

[Somerset Squall]

South Indian Ocean:

97S developed into TC 19S.

South Pacific:

A rapidly consolidating LLC is located out in the south Pacific, west of Tahiti. Invest 99P has good chances of developing over the next 24hrs as formative banding is improving already, shear is low and waters are very warm. JTWC have issued a tropical cyclone formation alert on the system.

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99P a few hours ago

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South Indian Ocean:

Invest 90S has formed, in the central south Indian ocean, south of Diego Garcia, around 13S, 77E. The sytem consists of a small, ill defined LLC with little or no convection associated with it. The invest could well contain the remnants of former TC 19S. Though waters are warm, shear is moderate to high so I think the chances of this one developing, in the near term at least, are poor.

Invest 91S has also developed, around 10S 96E, near Christmas Island. Shear is moderate to high once more, but the system may well move west-southwest into an area of lower shear over the next few days, which may allow a little development.

Overall, shear is quite high in large swathes of the South Indian Ocean, so these two invests may have a hard time developing.

South Pacific:

99P developed into TC Joni, but there are no other invests in the basin.

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South Indian Ocean:

Invest 90S has dissipated.

91S has become slightly better organised today, particularly over the last few hours. Where there was little convection associated with the system yesterday, there has been a modest increase in convection today over the LLC. This could just be a flare up so we will need to wait and see if it persists. Conditions aren't really favourable for development as moderate to high shear persists, and this shear looks like it may continue, at least for the next couple days. Therefore, chances for development are poor.

South Pacific:

Invest 92P has formed in the Gulf Of Carpentaria. Convection is flaring and is showing signs of weak rotation. Shear is low and waters warm, but the system may not have enough time to develop into a TC before moving inland on the westward track.

Edited March 13, 2009 by Somerset Squall

[Somerset Squall]

South Indian Ocean:

91S remains disorganised. Sporadic convection is flaring around an elongated LLC, which is failing to consolidate due to high shear. Chances in the near term at least are poor for this system to form into a TC.

South Pacific:

92P has moved rapidly westwards over land today and is just emerging over water near Darwin. The system lacks a well defined LLC and also convection is highly disorganised. Wind shear is moderate to high so development is not expected.

Invest 93P has formed in the Coral Sea. Disorganised convection and thunderstorms are flaring and are showing signs of weak rotation. Waters are amply warm for development, and shear is fairly low, currently at 10kts. Some slow development is possible over the coming days.

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93P

[Cookie]

91S chances of development to fair for next 24hrs

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South Indian Ocean:

91S has become a little better organised today. The LLC has got more definition and has slowly been spinning up with pressure gradually falling. In addition, convection has been attempting to wrap around the LLC. Shear is slowly easing in the area, which could explain why 91S is looking better today. JTWC assess the disturbance's chances of development in the next 24 hours as fair.

The image below shows shear is much less than yesterday, now only about 10kts over the system (located around 10S 88E):

And the next image shows the shear is easing in a small pocket where 91S is located:

You can see that shear is fairly high over most of the South Indian Ocean. 91S needs to make use of this small area of lower shear because shear may ramp up again at any time.

South Pacific:

Invest 92P remains highly disorganised. Further development is not expected.

Invest 93P has dissipated.

Invest 94P has formed, near Fiji. Deep convection is flaring around an ill defined LLC. Some slow development is possible as shear is low and waters are very warm.

Edited March 15, 2009 by Somerset Squall

[Cookie]

nice images mate, another great update thanks for the hard work

[Somerset Squall]

South Indian Ocean:

Invest 91S has lost organisation today. The LLC is very elongated and convection is very messy. The system is embedded in a monsoon trough and is barely discernable. JTWC have downgraded it's chances of development to poor. Shear is low for now but could well increase again over the next day or so, further hindering development.

92P is now in the South Indian Ocean. Convection has increased slightly over an ill defined LLC just of the northwest Australian coast. There are hints of an isolated banding feature south of the system. Shear is decreasing so there is a small chance of some slow development.

Looks like the very large lull in the South Indian Ocean season continues!

South Pacific:

94P remains disorganised with convection continuing to flare, but not persist around an ill defined LLC. The system is currently providing heavy rains to Fiji but this should ease as the system eases westwards. Significant development is not expected over the next couple days due to the disorganisation of the system.

Invest 95P has formed, west of Rarotonga. This system is fairly near where Joni formed. A rapidly consolidating LLC is visable on latest satellite imagery, along with good formatinve banding features and some very deep convection over the LLC. Conditions are excellent, with non-existant shear, radial outflow, hot sea temps and plenty of moisture available. JTWC has issued a tropical cyclone formation alert on the system.

Image of 95P:

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South Indian Ocean:

There is very little left of 91S now. A few small cells of convection are flaring near a very weak LLC. Shear is still high making development very unlikely.

92P is getting better organised. Deep convection is persisting over a well defined LLC. In addition, banding features are forming and a healthy amount of convection is wrapping into the centre. The system is north-northwest of Port Hedland, NW Australia, as is drifting generally westwards in an environment of low shear and warm sea temps. I think the chances of this one developing in the next couple days is good.

Invest 96S has formed a few hundred miles west of Cocos Island. Moderate shear is impinging on the system, and is preventing convection from developing over the LLC. Chances of development are poor as long as the shear persists.

South Pacific:

94P has changed little in organisation since yesterday. Patchy, deep convection continues to flare and is showing signs of weak rotation. There certainly is no sign of a well defined LLC as yet. The system continues to bring thunderstorms to Fiji as the disturbed area remains practically stationary. Models are keen on moving this system westwards and slowly developing it as shear continues to lessen. Given the current disorganisation of the system, development, if any will be slow.

Invest 95P is now TC Ken.

Image of 92P, the system most likely to develop IMO:

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South Indian Ocean:

Invest 91S has dissipated.

Invest 92P continues to look very well defined and JTWC has issued a tropical cyclone formation alert on the system, noting that the disturbance has some deep convection over the well defined LLC and some good banding features. I suspect 92P will be upgraded to a TC very soon.

Convection has increased a little with 96S this evening, but shear is still removing the bulk of convection from the LLC. Any further development will depend on shear levels.

South Pacific:

Invest 94P remains very disorganised any any further development will be slow.

Invest 97P has formed in the northern Coral Sea, a few hundred miles northwest of New Caledonia. Disorgansied convection and showers are showing signs of broad rotation. Shear is high in the area, around 20kts, so this system will find it hard to get better organised over the next few days, unless of course, shear eases.

Edited March 17, 2009 by Somerset Squall

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At least we have ken

[Cookie]

Just had a bit more proper look at 92P looking better all the time.

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South Indian Ocean:

92P is now TC Ilsa.

96S is still looking fairly non-descript this morning. It has to be said that convection associated with the system is very deep, but it is nowhere near the proposed centre of circulation. Wind shear is still high over the system, though looking at the latest CIMSS wind shear tendancy charts, this may well ease over the coming days, which could allow for some slow development (96S is located around 12S 88E):

South Pacific:

94P has dissipated.

97P is slowly becoming better organised. Convection is increasing near a slowly deepening LLC, and as shear is currently low over the system, further development is likely. 97P may become a TC before been whisked away southwards by an approaching trough later in the week which is expected to move into the Coral Sea. The infrared image clearly shows the deep convection consolidating over 97P:

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South Indian Ocean:

Convection is exploding over the LLC of 96S this evening. Shear is now low, so further development is possible, as waters are also warm. I think there is a fair chance of this one becoming a TC in the next day or so.

South Pacific:

97P remains highly disorganised. Convection is flaring near an ill defined LLC, but lacks any consolidation or defined pattern. Shear is moderate over the system, and very high to the south. Depends then, on where the system drifts as to whether there will be any further development.

Image of 96S:

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South Indian Ocean:

96S remains disorganised, and shear is increasing again over the system. There is still some deep convection flaring around the LLC, but it isn't as wide in coverage as yesterday evening, probably due to the increased shear. As shear looks like it will stick around for a bit, I now think 96S' chances of development in the near term are poor.

South Pacific:

97P has dissipated.

Invest 98P has formed in the same disturbed area that 97P was located. The LLC of 97P has dissipated but a new LLC has formed in the vicinity, and is tucking itself under some deep, concentrated convection. As the hours tick by, 98P is becoming better organised in the favourable conditions of low shear, warm waters and increasing outflow. Formative banding features are wrapping around the LLC maintaining some deep convection very near or over the increasingly well defined LLC. As the favourable conditions persist, further development should occur as the system slowly meanders generally westwards. It's unclear whether 98P will affect the east coast of Australia as yet, as a scenario I mentioned earlier of a trough pushing into the Coral Sea may well steer 98P southeastwards, but a west-southwest track appears just as likely at the moment as the models are coming into more disagreement on the positioning and evolution of the afformentioned trough. Overall, things look good for 98P to form into a TC over the next 24-48hrs.

Edited March 19, 2009 by Somerset Squall

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98P

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its looking even messier then before

[Cookie]

pardon me, but this next image looks like something I did when I was 3 in nursery

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pardon me, but this next image looks like something I did when I was 3 in nursery

LOL

South Indian Ocean:

96S remains disorganised. Limited convection is being displaced from the LLC by moderate shear. Sea temperatures are very warm, and shear is not at a majorly destructive level so slow development is still possible over the coming days.

South Pacific:

Invest 98P has dissipated. There is no LLC left, just a broad trough with scattered convection. It appears wind shear increased which stopped the system from consolidating.

[Somerset Squall]

South Indian Ocean:

96S has become much better organised today. Convection is persisting over a better defined LLC, and banding features are forming. The disturbance is located in lower shear, and improving outflow is sustaining convection near the centre. JTWC have upgraded the chances of development to fair for the next 24hrs. I think there may be a good chance of development in the next 48hrs.

Invest 99S has formed, on the east coast of Mozambique. Land interaction is hindering development, but explosive convection is forming over the ill defined LLC. Chances for development are poor unless the LLC moves away from the coast.

South Pacific:

No invests.