Tropical Storm Higos

[Cookie]

we have another new system

http://www.wunderground.com/tropical/tracking/wp200821.html

[Somerset Squall]

The West Pacific is on fire at the moment, indeed another storm has formed. Tropical Storm 21W is expected to track northwestwards along the southwestern periphery of a subtropical steering ridge to the north, taking the storm through the Philippines. 21W may strengthen a little more from it's current intensity (35kts), before land interaction hinders further development. Large rainfall totals will occur as the system moves through the Philippines and significant flooding may occur as a result. Not a good track at all it has to be emphasised. The only saving grace is that 21W hasn't got much time to get really strong before it trecks over land. in around 72hrs time, 21W will emerge in the South China sea, where further strengthening is possible. The Philippines is really not a good place to be right now as 21W could well be a big rainmaker.

[Cookie]

new update

Storm Alert issued at 29 Sep, 2008 12:00 GMT

Tropical Storm TWENTYONE is forecast to strike land to the following likelihood(s) at the given lead time(s):

Green Alert Country(s) or Province(s)

the Philippines

probability for TS is 35% in about 24 hours

Green Alert City(s) and Town(s)

Tacloban (11.2 N, 125.2 E)

probability for TS is 35% in about 24 hours

San Juan (10.3 N, 125.2 E)

probability for TS is 35% in about 24 hours

Surigao (9.7 N, 125.5 E)

probability for TS is 35% in about 24 hours

Note that

Green Alert (Low) is TS to between 31% and 50% probability.

TS means Tropical Storm strength winds of at least 39 mph, 63 km/h or 34 knots 1-min sustained.

[Somerset Squall]

21W has been upgraded to Tropical Storm Higos, with intensity of 45kts. Convection is deep and widespread so torrential rains will occur over the Philippines. The track over the Philippines will halt intensification and could even weaken the storm slightly, until it emerges over the south China sea and starts to strengthen again. Higos will emerge over water in around 48-60hrs time where it will be greeted by warm waters and low shear which should aid the predicted strengthening in a few days time. JTWC have Higos at 60kts at 120hrs, and it could well become a typhoon prior to a second landfall, currently progged to be in Southeastern China, east of Hong Kong. However, as with any forecast this far out, it's is subject to change so Higos needs closely watching.

[Cookie]

new update

Tropical Storm HIGOS is forecast to strike land to the following likelihood(s) at the given lead time(s):

Yellow Alert Country(s) or Province(s)

the Philippines

probability for TS is 90% currently

Yellow Alert City(s) and Town(s)

Oras (12.1 N, 125.4 E)

probability for TS is 90% within 12 hours

Sorsogon (13.0 N, 124.1 E)

probability for TS is 80% within 12 hours

Tacloban (11.2 N, 125.2 E)

probability for TS is 75% within 12 hours

Daet (14.2 N, 122.9 E)

probability for TS is 60% in about 24 hours

Manila (14.6 N, 121.0 E)

probability for TS is 55% in about 24 hours

Green Alert City(s) and Town(s)

San Jose (15.8 N, 121.5 E)

probability for TS is 40% in about 36 hours

Mamburao (13.2 N, 120.7 E)

probability for TS is 40% in about 36 hours

Note that

Yellow Alert (Elevated) is CAT 1 or above to between 10% and 30% probability, or TS to above 50% probability.

Green Alert (Low) is TS to between 31% and 50% probability.

CAT 1 means Typhoon strength winds of at least 74 mph, 119 km/h or 64 knots 1-min sustained.

TS means Tropical Storm strength winds of at least 39 mph, 63 km/h or 34 knots 1-min sustained.

[Somerset Squall]

Land interaction and moderate shear is taking it's toll on Higos this afternoon. Convection has decreased and has been displaced west of the LLC. Higos is not expected to strengthen over the next 36hrs as it traverses the Philippines. However, intensification to a typhoon is possible in the South China sea prior to a second landfall. Location of final landfall has shifted westwards from earlier and currently it looks like Hong Kong is in the firing line. I cannot stress how uncertain the final tracking is though, it's been chopping and changing and most likely will continue to do so.

[Somerset Squall]

Higos continues to struggle as it staggers across the rugged terrain of the Philippines. Although the convection associated with Higos remains deep, the LLC is poorly defined. However, Higos is expected to recover over the South China sea when it emerges back over the warm waters tomorrow. Higos may still become a typhoon prior to landfall near Hong Kong. It all depends how quickly Higos can re-organise. Don't expect immediate strengthening once it emerges over water as Higos' inner core is quite messy and will take time to sort itself out before proper intensification can begin.

[Cookie]

thanks for the updates mate, its been one system after another after another

new update.

Storm Alert issued at 1 Oct, 2008 18:00 GMT

Tropical Depression HIGOS is forecast to strike land to the following likelihood(s) at the given lead time(s):

Yellow Alert Country(s) or Province(s)

China

probability for CAT 1 or above is 20% in about 72 hours

probability for TS is 40% in about 72 hours

Hong Kong

probability for CAT 1 or above is 15% in about 72 hours

probability for TS is 40% in about 72 hours

Macau

probability for CAT 1 or above is 15% in about 72 hours

probability for TS is 40% in about 72 hours

Yellow Alert City(s) and Town(s)

Guangzhou (23.1 N, 113.3 E)

probability for CAT 1 or above is 10% in about 72 hours

probability for TS is 35% in about 72 hours

Hong Kong (22.4 N, 114.2 E)

probability for CAT 1 or above is 10% in about 72 hours

probability for TS is 35% in about 72 hours

Note that

Yellow Alert (Elevated) is CAT 1 or above to between 10% and 30% probability, or TS to above 50% probability.

CAT 1 means Typhoon strength winds of at least 74 mph, 119 km/h or 64 knots 1-min sustained.

TS means Tropical Storm strength winds of at least 39 mph, 63 km/h or 34 knots 1-min sustained.

[Somerset Squall]

Higos weakened to a tropical depression last night, and remains one today, with intensity set at 30kts. Higos has a poorly defined, elongated LLC with convection seemingly being suppressed by convergence. This convergence is choking convection by causing dry, subsiding air to affect the depression. Upper level divergence (air rising and departing at the highest level) which fuels convection is severely lacking at present. The waning convection is probably one factor in the low level centre remaining disorganised. However, as Higos recurves northwards towards Hong Kong, convergence will become less of a factor and as sea temps remain warm and shear low, Higos should regain tropical storm status before making landfall. Higos probably hasn't got enough time to become a typhoon now, and the JTWC have backed off the intensity forecast, now suggesting a more modest 50kt peak.

[Cookie]

thanks for the great updates mate

[Somerset Squall]

Higos is a prime example of how difficult it is to forecast the future intensity of a tropical cyclone. A few days ago, it looked quite likely that Higos would become a typhoon in the South China sea, prior to a second landfall. Instead, it now looks like Higos will remain a tropical depression right up to this landfall.

Secondly, the difficulty we still have with forecasting future track (though I would say there is more skill with this than intensity). Higos was intially forecast to make landfall east of Hong Kong. Instead, a final landfall in Hainan Island looks the final outcome, due to the subtropical steering ridge to the north being stronger than anticipated.

Convection has increased this morning in association with Higos, but the LLC remains weak and elongated. It seems the marginal environment and it's long track over the rugged terrain of the Philippines proved too much for this system to handle. As I said above, Higos is not expected to become a tropical storm again, probably due to land interaction with Hainan Island, dry air being entrained from land, and the fact the LLC remains highly disorganised.