At one point on Saturday, the Joint Typhoon Warning Center analyzed 150 mph winds within Phanfone, designating it super typhoon. The JTWC has since designated Phanfone a typhoon with wind speeds below 150 mph.As of Saturday afternoon (local time), high winds are already being felt in the Daito Islands, which are part of Okinawa Prefecture, where a wind gust of 101 mph was reported before the wind observations were knocked offline. As of this writing, most of the strongest winds are being observed on the Daito Islands as well as parts of the Amami Islands farther north, where sustained winds are in the 40 to 45 mph range. Phanfone has been moving to the north-northwest, and soon it will soon curve to the north before moving north-northeast. However, there are still some key uncertainties about Phanfone's track, which will ultimately determine impacts for millions.
Although Phanfone is moving into an area of increasing vertical wind shear (changes in wind speed and direction with height) as well as cooler ocean waters, the storm will be slow to weaken and will still be a very intense system as it approaches the larger islands of Japan.
Potential Japan Impact
Phanfone has reached the western edge of a bubble of high pressure aloft -- and tropical cyclones often turn northward in those situations before eventually being forced northeastward by the prevailing upper-level westerlies, usually becoming post-tropical systems in the process.
The question remains exactly how sharp a turn Phanfone makes, and, therefore, what the exact track of the core circulation is.
Given Phanfone's large wind field and the latest forecast trends, it appears Phanfone won't curve sharply enough to avoid at least some impacts from high winds over at least parts of central and eastern Honshu, and possibly western Honshu, Kyushu, Shikoku and the northern Ryuku Islands.
Uncertainty remains, however, regarding Phanfone's intensity once it tracks near the Japanese mainland. Increased wind shear will induce weakening, but the longer the typhoon keeps its current intensity, the stronger it may still be once it tracks over Japan.
As a result, damaging winds may rake (downed trees, power outages, some structural damage) at least part of those areas this weekend, along with the threat of storm surge flooding in surge-prone areas.
These areas (the Kansai, Chubu and Kanto regions) including Kyoto, Kobe, Osaka, Nagoya and Tokyo, have a combined population of 85 million.
Rainfall Threat
Regardless of the exact path of Phanfone, there's increasing concern about the threat of heavy rainfall from this storm.
The map above shows a computer model forecast for rainfall through Tuesday. The map gives a general idea of where heavy rainfall may fall, but it's important to bear in mind that the official track forecast may differ from the forecast from any individual computer forecast model.
Additionally, Japan's steep terrain often leads to large variations in local rainfall that often aren't captured by the global models, so the above map is only a general idea of where the heaviest rain may fall.
Some of the areas in Phanfone's path saw historic rainfall from the one-two punch of Tropical Storm Nakri and Typhoon Halong in August. The city of Kochi had over 61 inches of rain in August, its wettest month in records dating back to 1886. The rural hamlet of Shigeto in the mountains of Kochi Prefecture picked up 94.41 inches of rain, crushing its previous all-time record for any calendar month by nearly 40 inches.
Track History
Phanfone was first declared a tropical depression early on September 29, local time, several hundred miles to the east of Guam, then tracked northwestward through the northern Mariana Islands, bringing locally heavy rain, gusty winds and high surf.Phanfone strengthened from a Category 1 equivalent typhoon (75 mph estimated max winds) early on the evening of October 1, local time (Japan is 13 hours ahead of U.S. EDT) to a Category 4 equivalent typhoon (130 mph estimated max winds) just 24 hours later, a jump of 55 mph (or 50 knots) in 24 hours.
"Phanfone had the dreaded pinhole eye rarely seen in tropical cyclones," said The Weather Channel hurricane specialist Michael Lowry. "The eye was so small even our best microwave satellites had trouble seeing it."
Stay with The Weather Channel and weather.com for more on this potentially dangerous typhoon.
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