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Southern Hemisphere: Invest Thread 2009


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Posted
  • Location: Taunton, Somerset
  • Weather Preferences: Snow, thunder, strong winds
  • Location: Taunton, Somerset

South Indian Ocean:

Thanks for that Cookie. It seems like however, the JTWC and BOM are in slight disagreement where 95S actually is. Bom clearly have it over water but JTWC are saying it's yet to move offshore. The system doesn't look as impressive as last night, convection has decreased and the LLC has lost definition, due to continued land interaction. JTWC assess the chances of TC development in the next 24hrs as remaining fair, but I think chances are good beyond this time scale as the system fully mves over the hot water.

South Pacific:

No invests.

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Posted
  • Location: Taunton, Somerset
  • Weather Preferences: Snow, thunder, strong winds
  • Location: Taunton, Somerset

South Indian Ocean:

Yes, invest 95S is slowly becoming better organised though progress is painfully slow. Moderate shear has prevented significant development, and as the system is heading quickly towards the coast there is a chance it may not develop in time at all. I think it will, but it'll be a weak, short lived affair.

As you say Cookie, invest 96S has formed in the eastern South Indian Ocean, at high lattitude, to the southwest of Sumatra. Deep convection in the area has been showing signs of rotation today and this suggests a LLC may be forming. Shear is moderate, which will hinder development. However, sea temps are pretty toasty so the system may slowly consolidate as it drifts south.

South Pacific:

No invests.

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Posted
  • Location: Tiree
  • Location: Tiree

95s

could make it to a cat 1 just before landfall

IDW60284-8.gif

96s

Australian Government Bureau of Meteorology

Western Australia Tropical Cyclone Warning Center Perth

TROPICAL CYCLONE OUTLOOK

Forecast for area south of 10S between 90E-110E

12:00 PM WDT February 28 2009

=====================================

TROPICAL LOW near 10.0S 102.0E at 9am WDT Saturday about 400 kilometres [220 nautical miles] west of Christmas Island

Central Pressure :1004 hectopascals

Recent movement :near stationary

Tropical Cyclone Formation Potential

====================================

Sunday: Low

Monday: Moderate

Tuesday: Moderate

REMARKS - The low is expected to gradually develop further in the following days and drift slowly to the south and then southeastwards. At this stage, gales are not expected at either Christmas or Cocos Islands within the next 48 hours.

----

Potential lowered to moderate now.

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Posted
  • Location: Saddleworth, Oldham , 175m asl
  • Weather Preferences: warm and sunny, thunderstorms, frost, fog, snow, windstorms
  • Location: Saddleworth, Oldham , 175m asl

Thanks for keeping us updated you two, it goes a bit quiet in here after the Atlantic season ends but I still find it fascinating.

Edited by James M
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Posted
  • Location: Taunton, Somerset
  • Weather Preferences: Snow, thunder, strong winds
  • Location: Taunton, Somerset
Thanks for keeping us updated you two, it goes a bit quiet in here after the Atlantic season ends but I still find it fascinating.

Thanks James :D

South Indian Ocean:

Invest 95S has failed to develop. Possible reasons for this could have been moderate shear, the fact that the LLC was moving so fast or, in the later stages, land interaction. The system is now well inland so development is no longer expected.

Invest 96S remains in a fair environment for development, with moderate shear being the only limiting factor. The system remains highly disorganised with very little evidence of a defined LLC. Further development, if any, will be slow.

Invest 97S has formed, in the central south Indian Ocean, near Diego Garcia. Limited convection is flaring near an ill defined LLC. Moderate to high shear is impinging on further development. The LLC (what you can make out of it as it's so weak) is almost entirely exposed due to the shear. Unless the environment improves, I think there is next to no chance of development.

South Pacific:

No invests.

Edited by Somerset Squall
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Posted
  • Location: Tiree
  • Location: Tiree
Thanks for keeping us updated you two, it goes a bit quiet in here after the Atlantic season ends but I still find it fascinating.

thanks James means a lot

97s

11_21367_94725ab7d44dd00.jpg

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Posted
  • Location: Taunton, Somerset
  • Weather Preferences: Snow, thunder, strong winds
  • Location: Taunton, Somerset

Thanks for the images Cookie.

South Indian Ocean:

96S became better organised in the early hours, with a well defined LLC forming and some deep convection building west of the centre. However, convection is being prevented from building over the centre from moderate easterly shear. 96S now looks less organised than Cookie's earlier image. JTWC have upgraded the chance of development in the next 24hrs to fair, but the system is going to have to overcome the shear to do that.

97S is in a very similar environment. Moderate to high easterly shear is also buffeting this system, and there is limited convection related to the poorly defined LLC. I still think chances are poor for this system to develop in the near term, and will only develop in the long term if shear eases. It's just as possible that the shear will destroy the LLC altogether.

South Pacific:

No invests.

The way things are going, the long wait for another TC will continue.

Edited by Somerset Squall
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Posted
  • Location: Taunton, Somerset
  • Weather Preferences: Snow, thunder, strong winds
  • Location: Taunton, Somerset

South Indian Ocean:

96S is becoming better organised and the JTWC have issued a tropical cyclone formation alert on the system, meaning chances for TC development within the next 24hrs is good. BOM are also expecting development in the next 24hrs. Shear is still currently strong, but 96S is moving southeastwards into an area of lower shear, which is expected to allow development. There is a strong LLC which is producing winds near the values of a weak TC already so this system just needs to maintain the convection near the centre to be upgraded. Poleward outflow is also expected to improve which should help this system intensify.

97S remains disorganised. The LLC is getting better defined but shear is displacing all convection west of the centre leaving the centre exposed. As the LLC is getting better defined, I'd say the chances for development into a TC over the next couple days is fair.

South Pacific:

No invests.

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Posted
  • Location: Taunton, Somerset
  • Weather Preferences: Snow, thunder, strong winds
  • Location: Taunton, Somerset

South Indian Ocean:

Invest 96S is now TC Gabrielle.

97S has not become any better organised today. However, conditions are becoming more favourable for development. Shear is much lower now and waters are warm. Outflow is also improving which should aid spin up of the circulation. However, the LLC is embedded in a monsoon trough, and less it seperates itself from this feature it will find it difficult to develop. Convection isn't very deep over the LLC, and JTWC explains why very well:

THE CONVECTION ASSOCIATED WITH THE SYSTEM HAS BEEN

FLARING, SHIFTING ALONG THE MONSOON TROUGH AND IS NOT CURRENTLY

CONSOLIDATING.

So, if 97S has any hope, it needs to pull away from the monsoon trough. More about monsoon troughs here:

http://en.wikipedia.org/wiki/Monsoon_trough

South Pacific:

No invests.

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Posted
  • Location: Taunton, Somerset
  • Weather Preferences: Snow, thunder, strong winds
  • Location: Taunton, Somerset

South Indian Ocean:

97S remains disorganised. The LLC is weak and elongated and convection is not persisting over the centre. Conditions are favourable with low shear and warm waters but the LLC is competing for convection with other vorticies within the monsoon trough so the system is failing to consolidate. As I said before, the system needs to become a seperate entity before development can occur.

South Pacific:

Invest 98P has formed, just off the coast of the Cape York Peninsula. Deep convection is flaring over an increasingly well defined LLC. Shear is low and waters very warm, however the system will soon move inland. I rate the chances of 98P being upgraded to a TC before landfall as poor. However, 98P may cross the peninsula and emerge into the Gulf Of Carpentaria, where shear values are higher but waters are very warm. This system could bring flooding rains to Queensland.

post-1820-1236192602_thumb.jpg

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Posted
  • Location: Tiree
  • Location: Tiree

thanks again for the updates :)

going away till Monday, so the updates will be all you'res mate, look forward to reading when I get back

Edited by cookie
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Posted
  • Location: Taunton, Somerset
  • Weather Preferences: Snow, thunder, strong winds
  • Location: Taunton, Somerset

Yeah, you can clearly see the difference. Have a good time wherever you're going, you never know, we may have a TC by the time you get back!

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Posted
  • Location: City of Gales, New Zealand, 150m ASL
  • Location: City of Gales, New Zealand, 150m ASL

Upper level anticyclone, low shear and forecast to become even less. Warm waters. Held back by a lack of low level circulation. An easterly surge over the next few days should see to that, and then we will have a decent system.

post-7526-1236247476_thumb.png

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Posted
  • Location: Taunton, Somerset
  • Weather Preferences: Snow, thunder, strong winds
  • Location: Taunton, Somerset

Maybe not a cat 5 Cookie but it looks like you may well miss a cyclone!

South Indian Ocean:

97S remains very disorganised. Further development, if any, will be slow. The system is still embedded in a monsoon trough.

South Pacific:

98P has become much better organised overnight, and JTWC have issued a tropical cyclone formation alert on the system. BOM are expecting a TC to form in the next 12 hours too. As you say J07, conditions are really good out there now. 98P has slowed and is now turning to the south as a trough resides to the west of the system and a ridge builds to the east. This should keep 98P off the coast for now, unlike previously thought. This will obviously give 98P time to develop and looking at the good central convection persisting over an increasingly well defined centre, the excellent banding features and the favourable environment, we should see a TC very soon, maybe even later today.

post-1820-1236250715_thumb.jpg

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Posted
  • Location: Taunton, Somerset
  • Weather Preferences: Snow, thunder, strong winds
  • Location: Taunton, Somerset

South Indian Ocean:

At risk of sounding like a broken record- yes, 97S is still disorganised. The LLC (or centre of weak rotation) remains ill defined, but convection has increased over the system. Conditions are generally favourable, but they have been for the last few days, and no development has occurred yet. Any development will be slow given the current disorganisation.

South Pacific:

As we all know, 98P is now severe TC Hamish.

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Posted
  • Location: Taunton, Somerset
  • Weather Preferences: Snow, thunder, strong winds
  • Location: Taunton, Somerset
what did I say?

:lol:

Well, not quite cat 5 on the SS scale but yes, it is on the Aussie scale. May become one on the SS scale yet! Just your luck isn't it!

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