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West Pacific/North Indian Ocean Invest/Season thread


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

This thread is to discuss the ongoing Western Pacific Typhoon season and also the North Indian Ocean cyclone season of 2014. Individual disturbances and invests can also be discussed here, and an individual thread made when a system reaches Tropical Depression/storm status by JTWC or JMA.

The West Pacific season has already gotten off to an active start, with 5 named storms, of which 2 have reached typhoon strength (JTWC classification), and a tropical depression. This activity has occured earlier than normal, you don't normally see these kind of number until you get into July most years. Will it continue? Well, an above normal season is forecast, in part due to the developing El Nino, which favours increased tropical cyclone activity over the Pacific due to warmer seas and generally lower shear.

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

North Indian Ocean:

Invest 92B has formed in the southeastern Bay Of Bengal. Convection is becoming increasingly persistent over a fairly well defined LLC. Shear is at moderate levels currently, but waters are warm and there is some good upper level outflow over the system. JTWC have issued a tropical cyclone formation alert on the system, indicating cyclone formation as 92B drifts towards the north or northeast. If this system forms, it'll become the second cyclone of the season (the first was back in January.)

West Pacific:

No invests.

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

North Indian Ocean:

 

Shear increased over 92B shortly after I posted, and the TCFA was cancelled by JTWC. Shear has kept the system below tropical cyclone strength as it has veered northwestwards and crossed the Bay of Bengal, towards the east coast of India. There remains some deep convection near the ill defined LLCC, which is delivering some very heavy rains to Vishakhapatnam and surrounding areas. JTWC assess TC formation chances as MEDIUM currently, though I think it's unlikely 92B will become a tropical cyclone before moving inland.

 

post-1820-0-66762200-1401010377_thumb.jp

 

West Pacific:

 

No invests.

 

 

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  • 2 weeks later...
Posted
  • Location: Leeds/Bradford border, 185 metres above sea level, around 600 feet
  • Location: Leeds/Bradford border, 185 metres above sea level, around 600 feet

Always interesting are these systems. Sadly too much dry air to hit land hard.

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

North Indian Ocean:

The system noted above is now invest 95A. The disturbance is becoming better organised, with deep convection expanding near a developing LLC. Shear is low over 95A, and sea temperatures are warm on the northeasterly track towards western India. JTWC indicate a MEDIUM risk of TC formation in the next 24hrs, with even higher chances after that.

West Pacific:

Invest 93W is present east of Taiwan. There is very little convective organisation currently, and JTWC are no longer mentioning it in their outlook.

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

West Pacific:

 

The Western Pacific basin has been quiet through the months of May and June, with just two storms forming through these months. However, we do have two invests out there currently that may develop further over the coming days.

 

Firstly, we have invest 90W, located around 150 miles northwest of Chuuk, at 8.7N, 150E. The system is large but the LLC is consolidating and is flanked by strong rainbands, particularly in the southern quadrant. Shear is low and waters warm. Additionally, the system is benifitting from good upper level outflow. JTWC assess the TC formation risk of this system as MEDIUM in the next 24hrs.

 

Secondly, we have invest 91W, located west of invest 90W, but out to the east of the Philippines. This system is struggling to develop or maintain much convection at present, and this could be due to a lack of upper level outflow, suppressing the rising column of air needed to fuel convection. Given that shear is low however, makes some slow development possible. JTWC assess the 24hr chance of TC formation from this system as LOW.

 

North Indian Ocean:

 

No invests.

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Posted
  • Location: The Netherlands
  • Location: The Netherlands

Western Pacific Ocean:

 

92W

 

In the wake of STY (Super typhoon) Neoguri, a new tropical low is spinning far to the east of the Philippine islands. As of 21:00 UTC, some cyclonic turning is evident on satellite imagery loops. The areal coverage of the convection is not very large, and the convection still lacks some organization. This is confirmed by the JTWC, which also indicates that the LLCC (low level circulation centre) is still very elongated and poorly defined.

 

Posted Image

Visible satellite imagery loop of 92W (Courtesy: NOAA)

 

 

The JTWC currently assesses the chances of development of this system as "low" within the next 24 hours. 

 

Even though development is unlikely within the next 24 hours, some models are/were keen on developing this system in a potent typhoon. For example, the GFS forecast track 5 days out of this low as of 8 July, 12Z, is given below:

 

Posted Image

Track and pressure forecast of 92W from the GFS (12Z). Courtesy: Florida State University.

 

The GFS shows the system deepening in a sub-980 hPa low at the end of the forecast period, with possible further deepening afterward possible. However, the UKMET and CMC show less development with this system. Of note is that all models given above have multiple lows assessed at the location of 92W1. I don't know whether this is due to multiple low pressure areas present or due to poor initialization.

 

Also note the large cool eddy far to the east of Taiwan (indicated by the yellow colours at that position), likely caused by upwelling of cool waters as a result of the passage of Neoguri.

 

North Indian Ocean:

 

No invests.

 

Sources:

http://www.ssd.noaa.gov/PS/TROP/floaters/92W/92W_floater.html

http://www.usno.navy.mil/NOOC/nmfc-ph/RSS/jtwc/ab/abpwweb.txt

1: http://moe.met.fsu.edu/cyclonephase/navgem/fcst/archive/14070912/index.html

Edited by Vorticity0123
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Posted
  • Location: Taunton, Somerset
  • Weather Preferences: Snow, thunder, strong winds
  • Location: Taunton, Somerset

West Pacific:

 

Invest 90W became Super Typhoon Neoguri.

 

As Vorticity states, we now have invest 92W. JTWC have issued a Tropical Cyclone Formation Alert this morning, which means JTWC now rate 92W's chances of becoming a tropical cyclone as HIGH in the next 24hrs. Convection is increasing over the developing LLC, which is becoming better defined with time. Conditions are favourable for further development, with low shear, warm waters and good outflow.

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  • 2 weeks later...
Posted
  • Location: Taunton, Somerset
  • Weather Preferences: Snow, thunder, strong winds
  • Location: Taunton, Somerset

West Pacific:

 

We have a bit of a train of systems across the West Pacific at the moment. Rammasun has died over southern China, we have Typhoon Matmo east of the Philippines, Invest 96W to the east of Typhoon Matmo, then Invest 97W way way out east, just west of the International Dateline.

 

96W appears to be showing signs of organisation. The LLC is still poorly defined, but convection is expanding nicely and is deep, which should aid the LLCC to become better defined. Shear is moderate, and outflow good. JTWC give a MEDIUM chance of TC formation in the next 24hrs.

 

97W is in the extreme east of the basin, just west of the dateline seperating this basin from the Central Pacific basin. JTWC don't mention this system in their outlook, at least yet. Convection is disorganised, and there is little sign of an LLC. Shear looks moderate over the system, which will most likely hinder development.

 

North Indian Ocean:

 

No invests.

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

West Pacific:

 

Invest 96W continues to show sign of organisation. JTWC have issued a Tropical Cyclone Formation Alert on the system, as just a small increase in organisation would result in the formation of a tropical depression. Shear has increased a bit more over the system, but it has been offset to some degree by outflow. The LLCC is currently not very well defined, but with the sustained convection over the system, this should allow for the LLCC to strengthen over the coming days.

 

Invest 97W is on the way out by the looks of things. Convection has largely dissipated today, and there is no real low level organisation with the remnants. Development appears unlikely.

 

Invest 98W has formed to the southeast of Invest 96W (which is located a little way east of the Philippines). Disorganised convection is pulsing in assocation with the invest but it is not showing signs of organisation. It is running into some shear to it's west, the same shear which is affecting 96W. JTWC do not mention this invest in their outlook, so short term development appears unlikely.

 

North Indian Ocean:

 

No invests.

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

West Pacific:

 

97W and 98W dissipated.

 

Invest 96W however, is STILL out there. Shear prevented the system from doing much over the last several days. The system has become HUGE, with areas of deep convection cycling around a very large monsoonal gyre. Shear remains moderate, but outflow good. JTWC assess the chances of TC formation as MEDIUM.

 

Track of the persistant invest so far (which has been around for 12 days now without becoming a tropical cyclone!):

 

Posted Image

 

post-1820-0-78977000-1406630494_thumb.jp

 

North Indian Ocean:

 

No invests.

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  • 1 month later...
Posted
  • Location: Taunton, Somerset
  • Weather Preferences: Snow, thunder, strong winds
  • Location: Taunton, Somerset

96W became Tropical Storm Nakri in late July.

Of significance is the fact that there have been no new storms since. I will have to look into it, but I cannot recall hearing about an August in the West Pacific with no tropical cyclone formation. It may well be a record.

We do have an invest, 90W, to the east of the Philippines. Like Nakri, it seems to have a very broad, monsoonal structure, and convection is highly disorganised. There appears to be multiple LLC's, none of which are well defined or have any dominance. Therefore, consolidation is likely to be very slow, despite a favourable environment.

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  • 1 year later...
Posted
  • Location: Hessen, GERMANY
  • Location: Hessen, GERMANY

Super Typhoon Nepartak about to slam into Taiwan. May well make landfall as Cat 5 equivalent within only a few hours.  Despite the very strong winds this beast is packing, it's the 300mm+ of rainfall coming in the next 36 hours which will be of most concern, causing likely flash flooding and landslides.

https://weather.com/storms/typhoon/news/tropical-storm-typhoon-nepartak-pacific-east-asia

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