Category 5 Phailin Nears India; Category 3 Nari Hits the Philippines

Extremely dangerous Tropical Cyclone Phailin has maintained Category 5 strength for six hours, and is expected to remain a Category 5 storm until it is just a few hours from landfall on the northeast coast of India on the Bay of Bengal, according to the 5 pm EDT Friday advisory from the Joint Typhoon Warning Center. Phailin put on a phenomenal burst of rapid intensification on Thursday, going from a tropical storm with 65 mph winds to a top-end Category 4 storm with 155 mph winds in just 24 hours, and is now at peak strength of 160 mph, tying it with Super Typhoon Usagi as Earth's strongest tropical cyclone of 2013. Satellite images show that Phailin maintained very intense thunderstorms with cold cloud tops in its eyewall, with the 5 pm EDT Friday satellite estimate of Phailin's central pressure at 911 mb. This makes Phailin equal in strength to the great 1999 Odisha Cyclone, which killed 9,658 people in India's Odisha province. Radar out of Visakhapanam, India shows that heavy rains from the outer bands of Phailin are already affecting the coast, and these bands were bringing rainfall rates of over an inch per hour, as estimated by microwave data from 18 UTC Friday. Phailin is over ocean waters that have warmed since Thursday, and are now 29 - 30°C. These warm waters extend to a lesser depth than before, and ocean heat content has dropped to a moderate 20 - 40 kJ/cm^2. Wind shear remains low, 5 - 10 knots, and Phailin has strong upper-level outflow, thanks to an anticyclone positioned in the upper atmosphere over the cyclone.


Figure 1. Microwave satellite image overlaid on an infrared satellite image of Tropical Cyclone Phailin, taken at approximately 18 UTC on October 11, 2013. At the time, Phailin was a Category 5 storm with winds of 160 mph. Image credit: Navy Research Lab, Monterey.

Forecast for Phailin
Phailin is likely to be the strongest tropical cyclone to affect India in fourteen years, since the great 1999 Odisha Cyclone. The models are in tight agreement that Phailin will make landfall in Northeast India on Saturday between 09 - 15 UTC about 100 miles to the southwest of where the 1999 cyclone hit. The India Meteorological Department (IMD) is predicting that a storm surge of up to 3.5 meters (eleven feet) will hit along a swath a coast to the right of where the center makes landfall. I expect that this is an underestimate, since the 1999 Odisha Cyclone brought a storm surge of 5.9 meters (19 feet) to the coast, and Phailin is larger in areal extent and just as strong. The region of the coast where Phailin is expected to hit is not as low-lying, though, which 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. Deforestation of the coastal mangroves in the storm surge zone was associated with increased death toll in that storm, according to Das and Vincent (2009), who concluded, "villages with wider mangroves between them and the coast experienced significantly fewer deaths than ones with narrower or no mangroves.". I expect that Phailin will weaken slightly before hitting the coast, due to interaction with land, and hit as a Category 4 storm with winds of 145 - 155 mph. The 1999 Odisha Cyclone hit land with top winds of 155 mph.


Figure 2. Elevation of the Odisha region of India, with the track of the 1999 Odisha cyclone and forecast track of Phailin overlaid. Phailin is predicted to hit a region of the coast about 100 miles to the southwest of where the 1999 cyclone hit. The coast is not as low-lying to the southwest, which should result in a lower storm surge death toll. The greatest storm surge occurs along the coast to the right of where the center crosses. Image credit: http://www.globalwarmingart.com

Phailin's heavy rains will be capable of causing very destructive flooding; the 00Z Friday rainfall forecast from the HWRF model (Figure 3) calls for a significant swath of 8 - 16" of rain along the path of Phailin inland. Rains from the 1999 Odisha cyclone killed more than 2,000 people 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.


Figure 3. The 00Z Friday rainfall forecast from the HWRF model calls for a significant swath of 8 - 16" of rain along the path of Phailin inland. Image credit: NOAA/NCEP/GFDL.

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

References
Kalsi, S.R., N. Jayanthi N, and S.K. Roy Bhowmik, 2004, "A Review of Different Storm Surge Models and Estimated Storm Surge Height in Respect of Orissa Supercyclonic Storm of 29 October, 1999," New Delhi: Indian Meteorological Department.

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.

Das, S., and J.R. Vincent, 2009, "Mangroves protected villages and reduced death toll during Indian super cyclone", Proc Natl Acad Sci U S A. 2009 May 5; 106(18): 7357–7360. Published online 2009 April 20. doi: 10.1073/pnas.0810440106


Figure 4. Radar image of Typhoon Nari over Luzon Island in the Philippines, taken at 12:53 am local time on October 12, 2013. Image credit: DOST - Project NOAH

Major Typhoon Nari hits the Philippines
Typhoon Nari hit the main Philippine island of Luzon Friday night local time as a Category 3 typhoon with 115 mph winds. The core of the storm passed about 80 miles north of the capital of Manila, and the storm dumped torrential rains in excess of ten inches to the northeast of Manilla, according to satellite estimates. Passage over Luzon weakened Nari, and the typhoon is now emerging into the South China Sea between the Philippines and Vietnam as a Category 2 storm with 105 mph winds. Nari has about two days over water to re-intensify before making a second landfall in Vietnam around 18 UTC on Monday. The 5 pm EDT Friday Joint Typhoon Warning Center advisory predicts that Nari will re-intensify to 110 mph winds, just below Category 3 strength.

Jeff Masters