Category 3 Typhoon Phanfone Headed Towards Japan; Tropical Storm Simon Forms in EPac

Typhoon Phanfone took advantage of light wind shear of 5 - 10 knots and very warm ocean temperatures of 30°C (86°F) to intensify into a dangerous Category 4 typhoon early Thursday morning. The typhoon's inner eyewall began collapsing later on Thursday morning as Phanfone entered an eyewall replacement cycle, reducing its intensity to a Category 3 storm with 125 mph winds. Once this cycle completes, Phanfone will have the opportunity to re-strengthen, as ocean temperatures will remain near 30°C (86°F) through Friday with light wind shear. Ocean temperatures will cool sharply and wind shear will rise on Saturday as the typhoon approaches Japan, weakening the storm. The models have come into better agreement on the track of Phanfone, but it remains uncertain if the typhoon will hit the main Japanese island of Honshu as the GFS, GFDL, and European models are calling for, or pass just offshore.


Figure 1. MODIS satellite image from NASA's Aqua satellite of Typhoon Phanfone taken at 04:20 UTC October 2, 2014. At the time, Phanfone was a Category 4 storm with 135 mph winds. Image credit: NASA.


Figure 2. Predicted precipitation for Typhoon Phanfone as simulated by the GFDL model at 06Z Thursday October 2, 2014. Phanfone was predicted to dump widespread rains of 8+ inches (yellow colors) across much of Japan. One area of particular concern is the Mt. Ontake volcano, which erupted on Saturday. Image credit: NOAA/GFDL.

Heavy rains from Phanfone will arrive in Japan on Saturday, and are likely to bring dangerous flash flooding and mudslides. The Thursday morning 06Z run of the GFDL model predicted that Phanfone would dump widespread rains of 8+ inches across much of Japan. One area of particular concern is the Mt. Ontake volcano, which erupted last Saturday, killing 47 and leaving dozens missing. Phanfone's heavy rains will mobilize Mt. Ontake's ash deposits into dangerous mudflows, seriously complicating the search for victims of Japan's deadliest volcanic eruption in 90 years.

Tropical Storm Simon forms in the Eastern Pacific
In the Eastern Pacific, Tropical Storm Simon formed Thursday morning a few hundred miles south of the Pacific coast of Mexico. Simon was headed west-northwest near 10 mph way from the coast, but is expected to bring 3 - 5 inches of rain to the southwest coast of Mexico. Simon is expected to recurve to the north early next week, and could be a heavy rainfall threat to Mexico's Baja Peninsula on Tuesday and Wednesday. Simon's formation gives the unusually busy 2014 Eastern Pacific hurricane season 18 named storms, 12 hurricanes, and 7 intense hurricanes so far. An average Eastern Pacific hurricane season sees just 15 named storms, 8 hurricanes, and 3 intense hurricanes during the entire year, with two of those named storms and one hurricane occurring after October 10. If Simon becomes a hurricane, as predicted by NHC, it will become the 12th consecutive named storm to become a hurricane in the Eastern Pacific, after Genevieve, Hernan, Iselle, Julio, Karina, Lowell, Marie, Norbert, Odile, Polo, and Rachel. The previous record for consecutive hurricanes in the Eastern Pacific was eight, set in 1992 (Orlene, Iniki, Paine, Roslyn, Seymore, Tina, Virgil, Winifred.) Thanks go to wunderground members CybrTeddy and Mark Cole for looking up these stats.


Figure 3. Dust from the Sahara can be seen streaming westwards across the tropical Atlantic in this October 1, 2014 composite image from the VIIRS instrument on the Suomi spacecraft. Two disturbances in the waters south of Canada, 97L and 98L, are also marked. Image credit: NOAA Visualization Lab.

Quiet in the Atlantic
A tropical wave predicted to come off the coast of Africa on Saturday is no longer being given support for development by our top three models for predicting tropical cyclone genesis. A major outbreak of dry air from the Sahara, unusual for this time of year, is currently in progress over the Tropical Atlantic, which will make it difficult for anything to form between Africa to the Lesser Antilles Islands over the coming week. Two disturbances in the waters south of Canada that were being given 10% chances of development on Wednesday by NHC, 97L and 98L, have decreased in organization since Wednesday, and are no longer being given a chance to develop.

Jeff Masters