Tropical Cyclones & Typhoons

Very dangerous Tropical Cyclone Phailin has made landfall on the northeast coast of India near the town of Gopalpur (population 7,000) at 16 UTC (noon EDT) Saturday, October 12, 2013. Phailin was weakening substantially at landfall, due to interaction with land, and was rated a Category 4 storm with 140 mph winds by the Joint Typhoon Warning Center (JTWC), four hours before landfall. The pressure bottomed out at 938 mb in Gopalpur as the eye passed over, and the city reported sustained winds of 56 mph, gusting to 85 mph, in the eyewall. A 938 mb pressure is what one expects to find in a Category 4 storm with 140 mph winds, using the “Dvorak technique” of satellite wind and pressure estimation. Satellite images show that Phailin’s intense thunderstorms have warmed and shrunk in areal coverage, and radar out of Visakhapanam, India also shows a weakening of the storm’s echoes as it pushes inland. Phailin is bringing torrential rains of over an inch per hour, as estimated by microwave satellite instruments.

Figure 1. Radar image of Phailin at landfall. Image credit: IMD.

Figure 2. MODIS satellite image of Tropical Cyclone Phailin, taken at approximately 07:30 UTC on October 12, 2013. At the time, Phailin was a top-end Category 4 storm with winds of 150 mph. Image credit: NASA.

Damage from Phailin
Phailin is the strongest tropical cyclone to affect India in fourteen years, since the great 1999 Odisha Cyclone. That storm hit with maximum sustained winds of 155 mph, and brought a storm surge of 5.9 meters (19 feet) to the coast. Phailin should be able to drive a similar-sized storm surge to the coast, since it is larger in areal extent than the 1999 cyclone (although somewhat weaker, with winds perhaps 20 – 30 mph lower.) Phailin’s storm surge and Category 3 to 4 winds will cause near-catastrophic damage to a 50-mile wide swath of the coast where the eyewall comes ashore, and to the right. Hurricane Katrina was weaker at landfall than Phailin, but Katrina had hurricane-force winds that covered a much larger area, making Katrina’s storm surge much more devastating than Phailin’s will be. I think the main danger from Phailin will be from its winds. I am particularly concerned about Phailin’s wind damage potential in the city of Brahmapur (population 350,000), the 58th largest city in India. Brahmapur lies about ten miles inland, and will likely experience sustained hurricane-force winds for several hours. Phailin’s flooding potential is another huge concern, as rainfall amounts of 6 – 12 inches will fall along a swath over 100 miles inland, triggering life-threatening flash flooding.

How strong was Phailin?
Questions have been raised about the India Meteorological Department (IMD) assessments of Phailin’s strength, which were considerably lower than that of the U.S. Joint Typhoon Warning Center (JTWC). Both centers use satellite estimates rather than direct measurements of the winds, so we don’t know which center is correct. It is true that satellite estimates using the same techniques give different results for the Atlantic and Pacific Oceans–i.e., a storm with the same appearance on satellite imagery will be weaker in the Atlantic than in the Pacific (see this chart of the differences.) It may be that this is the case in the Indian Ocean as well. IMD has looked at some buoy data to try and calibrate their satellite strength estimates, but high-end tropical cyclones are uncommon enough in the Indian Ocean that I doubt we really know whether or not Indian Ocean cyclones have the same winds as a hurricane in the Atlantic with the same satellite signature. Another thing to consider is that the IMD uses 10-minute average winds for their advisories, and JTWC uses 1-minute, so the winds in the IMD advisories will be lower by at least 6%, due to the longer averaging period. This issue could be cleared up if India had its own hurricane hunter aircraft; there have been some high-level discussions about India getting a C-130 aircraft like the U.S. Air Force uses to fly into tropical cyclones and take measurements of the actual winds.

Figure 3. MODIS satellite image of Typhoon Nari, taken at approximately 02:30 UTC on October 12, 2013. At the time, Nari was a Category 1 storm with winds of 90 mph. Image credit: NASA.

Typhoon Nari hits the Philippines
Thirteen people were killed and 2.1 million people lost power on the main Philippine island of Luzon afterTyphoon Nari hit on Friday night near midnight local time. Nari was a Category 3 typhoon with 115 mph winds a few hours before landfall. The core of the storm passed about 80 miles north of the capital of Manila, sparing the capital major flooding, but the storm dumped torrential rains in excess of ten inches to the northeast of Manilla. Passage over Luzon weakened Nari to a Category 1 storm, but it is already beginning to re-organize over the South China Sea between the Philippines and Vietnam. Nari is under moderate wind shear of 15 – 20 knots, which should keep intensification relatively slow, and increasing interaction with land will act to slow intensification on Sunday and Monday. Nari could be near Category 3 strength with 115 mph winds by Monday, and landfall in Vietnam is expected around 21 UTC on Monday.

Typhoon Wipha a threat to Japan
Category 1 Typhoon Wipha is intensifying as it heads northwest towards Japan, and the storm is expected to reach major Category 3 strength by Monday. By Tuesday, Wipha will recurve to the northeast and begin weakening, passing very close to Tokyo, Japan, sometime between 00 – 12 UTC on Wednesday. High winds and heavy rains from Wipha may be a concern for the Fukushima nuclear site, where workers continue to struggle with high radiation levels in the wake of the 2011 tsunami that damaged the reactors.

98L in the Eastern Atlantic weakening
A tropical wave (Invest 98L) located midway between Africa and the Lesser Antilles Islands is headed west to west-northwest at 10 – 15 mph. Satellite loops show that 98L has lost most of its organization and heavy thunderstorms since this morning. The disturbance is under a high 20 – 30 knots of wind shear, and the shear is expected to remain high for the next three days. The UKMET model shows some weak development of 98L by early next week, but the European and GFS models do not. In their 2 pm EDT Saturday Tropical Weather Outlook, NHC gave the disturbance 2-day development odds of 30%, and 5-day odds of 30%. 98L’s projected west-northwest track is expected take it close to the Northern Lesser Antilles Islands by Wednesday, according to the 00Z Saturday run of the European model.

Thanks go to wunderground member thunderfrance for posting the link to the weather station at Gopalpur, India.