Tropical Storm Mekkhala

[Somerset Squall]

A tropical disturbance has been located in the South China sea over the past few days, whilst moving very little. It has battled strong shear and therefore did not develop much. The shear was caused by the outflow from Super Typhoon Jangmi. As Jangmi has now weakened and moved farther away, the distubance has gained organisation and deep convection, particucularly in the western quadrant. This has prompted JTWC to initiate advisories on Tropical Depression 20W.

20W is located to the southeast of Hainan Island. Most of the convection is displaced west of the well defined LLC as shear is still moderate from Typhoon Jangmi. However, shear will continue to ease and 20W is forecast to become a tropical storm before landfall on Hainan Island in around 24 hours time. Land interaction will weaken 20W as it moves westwards along the island. 20W is forecast to briefly emerge over water before a second landfall in northern Vietnam, most likely as a tropical depression. 20W is a very moisture laden depression and is therefore more likely to cause problems from rain than wind. As ever, track forecasts may change but a general westwards heading is predicted due to the development of a subtropical steering ridge to the north. The timing of the westwards turn will decide whether 20W will make a direct landfall on Hainan Island, if it doesn't, it may become a little stronger than forecast (35kts) and be stronger at landfall on the coast of Vietnam.

[Cookie]

first update

Storm Alert issued at 28 Sep, 2008 18:00 GMT

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

Green Alert Country(s) or Province(s)

China

probability for TS is 45% in about 24 hours

Green Alert City(s) and Town(s)

Yaxian (18.4 N, 109.4 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.

[Cookie]

we have a name

Storm Alert issued at 29 Sep, 2008 6:00 GMT

Tropical Storm MEKKHALA 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 TS is 60% within 12 hours

Green Alert Country(s) or Province(s)

Vietnam

probability for TS is 50% within 12 hours

Laos

probability for TS is 40% in about 24 hours

Green Alert City(s) and Town(s)

Yaxian (18.4 N, 109.4 E)

probability for TS is 50% within 12 hours

Da Nang (16.1 N, 108.2 E)

probability for TS is 50% within 12 hours

Dong Hoi (17.5 N, 106.6 E)

probability for TS is 45% in about 24 hours

Dong Ha (16.8 N, 107.1 E)

probability for TS is 45% in about 24 hours

Vinh (18.7 N, 105.7 E)

probability for TS is 35% in about 24 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]

we have a name

Indeed, 20W is now Tropical Storm Mekkhala. Intensity has increased a little more than expected with intensity currently at 45kts. The track forecast has also changed, with Mekkhala now forecast to move south of Hainan Island. This means two things: Hainan Island will be spared quite as much rainfall ans strong winds, and also it gives the storm more time over water in which to strengthen. Mekkhala isn't expected to become a typhoon but may intensify a little more prior to landfall in Vietnam.

[Somerset Squall]

Mekkhala has intensified some more just off the coast of Vietnam. Intensity has been increased to 55kts, and this may have been caused by the fact that Mekkhala has a very good outflow channel. Landfall is imminent, and indeed heavy rains and now damaging winds are spreading inland accross Vietnam.

[Cookie]

was meant to get someone to re-name but it slipped my mind sorry mate.

new update

Storm Alert issued at 29 Sep, 2008 18:00 GMT

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

Yellow Alert Country(s) or Province(s)

Vietnam

probability for TS is 85% currently

China

probability for TS is 75% currently

Laos

probability for TS is 75% within 12 hours

Yellow Alert City(s) and Town(s)

Dong Hoi (17.5 N, 106.6 E)

probability for TS is 80% within 12 hours

Dong Ha (16.8 N, 107.1 E)

probability for TS is 80% within 12 hours

Vinh (18.7 N, 105.7 E)

probability for TS is 65% within 12 hours

Da Nang (16.1 N, 108.2 E)

probability for TS is 55% currently

Green Alert City(s) and Town(s)

Yaxian (18.4 N, 109.4 E)

probability for TS is 50% currently

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]

was meant to get someone to re-name but it slipped my mind sorry mate.

No worries Cookie mate. Thanks for the updates.

Mekkhala is now pushing well inland and intensity has been reduced to 45kts. JTWC has issued it's final warning as Mekkhala is expected to dissipate within 24hrs. Mekkhala did have hints of an eye before landfall but I'm confident it wasn't a typhoon at landfall as winds were only sampled to be at 55kts.

Mekkhala will continue to bring heavy rains to Vietnam, Laos and perhaps eastern Thailand before petering out.

[Cookie]

thanks for the updates mate :lol: