western pacific Tropical Storm Jangmi

[Somerset Squall]

A tropical depression with 30kt winds has formed 575 nautical miles southeast of Manila, Philippines. The depression has some moderately deep convection obscuring the LLCC, with some fairly well developed banding features flanking it. The environment is favourable, with low shear, good outflow and warm waters beneath the depression. However, landfall in the Southern Philippines is imminent, so short term strengthening will be limited by this. As 23W moves over the warm waters in between the islands of the southern Philippines, it has the potential to reintensify, and JTWC expect a peak of 45kts at this point. Thereafter, once 23W moves out into the South China Sea, a surge of cold northeasterly winds aloft will increase shear and drive cold, dry air into the system, causing weakening to occur as 23W continues westwards under the sreering influence of ridging to the north.

Edited January 27, 2015 by Somerset Squall

[Vorticity0123]

A tropical depression with 30kt winds has formed 575 nautical miles southeast of Manila, Philippines. The depression has some moderately deep convection obscuring the LLCC, with some fairly well developed banding features flanking it. 

 

This tropical cyclone is certainly looking quite well organized from the start. In fact, the JTWC have upgraded the system to a tropical storm, with 35 kt winds. The JMA (japan meteorlogical agency) has not yet done so, and that is why the system has not been named yet. On top of this, CIMSS satellite intensity estimates have the system assessed at 55 kt, quite a bit higher than assessed by the JTWC. The satellite intensity trends can be seen below:

 

CIMSS ADT satellite intensity trend. The image does auto-update itself.

 

At the time of writing (23 UTC, 28-12-2014), 23W has intensified 20 kt in just 14 hours (if the satellite intensity estimates are correct). However, the cyclone ios already making landfall, so its intensification will be short-lived. It will be interesting to see whether the system can retain its organization at passage over land.

 

Sources:

http://www.jma.go.jp/en/typh/

http://www.usno.navy.mil/JTWC/

http://tropic.ssec.wisc.edu/#

[Somerset Squall]

Now Tropical Storm Jangmi, with winds of 40kts. The previous incarnation of Jangmi is my profile picture incidentally.

Edited December 29, 2014 by Somerset Squall

[Somerset Squall]

Jangmi's winds increased to 45kts this afternoon according to JTWC, but land interaction has caused some slight weakening, with winds down to 40kts. Some re-intensification is expected after emergence into the South China Sea, but this will be somewhat short lived due to increasing northeasterly shear forecast as Jangmi moves further into the South China Sea.

[Somerset Squall]

Jangmi has died a death crossing the southern Philippines. Shear rose prematurely, stripping the LLCC of it's convection. The remnant low is meandering to the south just west of the southern Philippines. Regeneration is not expected.

Edited December 31, 2014 by Somerset Squall