Category 3 Tropical Cyclone Phailin Rapidly Intensifying, Headed Towards India

Very dangerous Tropical Cyclone Phailin, in the North Indian Ocean's Bay of Bengal, has put on an impressive burst of rapid intensification, going from a tropical storm with 65 mph winds to a formidable Category 3 storm with 115 mph winds in just twelve hours. Satellite estimates of Phailin's strength at 8 am EDT ranged as high as 135 mph. Satellite images show that Phailin, whose name means "a sapphire" in Thai, continues to intensify. The cloud tops of the very intense thunderstorms in the eyewall are expanding and cooling, showing that their updrafts are growing stronger and pushing the clouds higher into the atmosphere. Water temperatures are warm, 28 - 29°C, and the ocean heat content is very high, 80 - 100 kJ/cm^2--a level often associated with rapid intensification. With wind shear low, Phailin should be able to continue to intensify until an eyewall replacement cycle begins. It is very difficult for a tropical cyclone to maintain an eye diameter less than ten miles across before the inner core grows unstable and the eyewall collapses, with a new, larger-diameter eyewall forming from an outer spiral band. This process typically weakens the top winds of a tropical cyclone by 5 - 15 mph, but spreads hurricane-force winds over a larger area of ocean, resulting a larger storm surge, but less wind damage. With Phailin's eye diameter already down to a tiny 9 miles, an eyewall replacement cycle is likely to occur by Friday morning.


Figure 1. MODIS satellite image of Tropical Cyclone Phailin, taken at approximately 07:30 UTC on October 10, 2013. At the time, Phailin had top winds of 75 mph. Image credit: NASA.

Forecast for Phailin
The models are in tight agreement that Phailin will track northwest into the northeast coast of India, with landfall expected to occur between 06 - 12 UTC on Saturday. The 11 am EDT Thursday forecast from the Joint Typhoon Warning Center predicts that Phailin will peak as a top-end Category 4 storm with 155 mph winds 12 hours before landfall. The India Meteorological Department (IMD) is predicting that Phailin will be a borderline Category 2/Category 3 storm at landfall. The 06Z Thursday run of the HWRF model predicted that Phailin would be a strong Category 3 storm with 130 mph winds at landfall on Saturday.


Figure 2. Storm surge forecast for Tropical Cyclone Phailin, made on October 10, 2013. The peak surge was predicted to be 87 cm (2.9'). This forecast is likely to be a considerable underestimate of the surge, given Phailin's recent rapid intensification. Image credit: IMD.

The Bay of Bengal is notorious for deadly tropical cyclones
There is good reason to be concerned when a major tropical cyclone forms in the Bay of Bengal. Twenty-six of the thirty-five deadliest tropical cyclones in world history have been Bay of Bengal storms. During the past two centuries, 42% of Earth's tropical cyclone-associated deaths have occurred in Bangladesh, and 27% have occurred in India (Nicholls et al., 1995.) Phailin is likely to be the strongest tropical cyclone to affect India in fourteen years, since the great 1999 Odisha Cyclone. That terrible storm hit Northeast India in the Indian state of Odisha (formerly called Orissa) near the city of Bhubaneswar, as a Category 4 storm with 155 mph winds on October 29, 1999. The mighty cyclone, which peaked at Category 5 strength with 160 mph winds and a 912 mb central pressure shortly before landfall, drove a storm surge of 26 feet (8 meters) onto the coast. The storm stalled just inland, dumping torrential rains on portions of India already saturated from the landfall of Category 4 Tropical Cyclone 04B just twelve days before. The catastrophe killed 9,658 people and left $2.5 billion in damage (1999 dollars), India's most expensive and fourth deadliest tropical cyclone in the past 100 years. Although Phailin is expected to hit the same province of India that the great 1999 Odisha Cyclone hit, Phailin's landfall location is predicted to fall about 100 miles farther to the south, in a region where the coast is not as low-lying. This should keep the death toll due to storm surge much lower compared to the 1999 Odisha Cyclone, where more than 70% of the deaths occurred due to the storm surge. The latest storm surge forecast from IMD (Figure 2) predicts a peak surge under 3', but this is much too low, considering Phailin's recent round of rapid intensification. Phailin's heavy rains will be capable of causing great destruction, as did the rains from the 1999 Odisha cyclone. More than 2,000 of the deaths from that storm occurred due to fresh water flooding in the town of Padmapur, located more than 150 miles from the coast. Deforestation was cited as a contributing cause to these destructive floods that killed 36% of the town's population.

Wunderground's weather historian Christopher C. Burt has a detailed post on India's tropical cyclone history.

References
Nicholls, R.J.N., N. Mimura, J.C. Topping, 1995, "Climate change in south and south-east Asia: some implications for coastal areas," J Glob Environ Eng 1995;1:137–54.



98L in the Eastern Atlantic more organized
A tropical wave (Invest 98L) located about 400 miles southwest of the Cape Verde Islands is headed west to west-northwest at about 10 mph. Satellite loops show that 98L has a modest area of heavy thunderstorms with a substantial amount of spin. The disturbance is under a moderate 10 - 20 knots of wind shear today, but the shear is expected to rise to the high range, 20 - 30 knots, Friday - Monday, making Thursday the most likely day for development. The UKMET model develops the disturbance into a tropical depression this week, but the European and GFS models do not. In their 8 am EDT Thursday Tropical Weather Outlook, NHC gave the disturbance 2-day development odds of 50%, and 5-day odds of 50%. 98L's projected west-northwest track is expected take it several hundred miles northeast of the Northern Lesser Antilles Islands by the middle of next week, according to the 00Z Thursday morning runs of the GFS and European models.

Typhoon Nari headed towards the Philippines
In the Western Pacific, Category 1 Typhoon Nari is expected to intensify into a Category 2 storm with 100 mph winds and make landfall on Luzon Island in the Philippines near 12 UTC Friday. Nari will then make a second landfall in Vietnam around 00 UTC on Tuesday.

Jeff Masters