Severe Tropical Storm Phanfone continues to intensify at a fast clip this morning. Phanfone has shown signs of rapidly improving organization so much so that the Joint Typhoon Warning Center has upgraded the system to a Category 1 Typhoon. The Japan Meteorological Agency is keeping it at Severe Tropic Storm strength but with winds that are on the cusp of typhoon-intensity. STS Phanfone is now moving away from the Mariana Islands after crossing there last night. Some thunderstorms and occasional rain showers are still possible, though, throughout today. IR Image from NRLMRY The latest satellite image above shows a rapidly developing Central Dense Overcast with tight bands wrapping around the circulation center. The system is also showing excellent outflow especially to the south and west. Environment conditions across the Philippine Sea remain favorable and should help Phanfone continue intensifying over the next few days. In fact, it may undergo a period of Rapid Intensification at some in its lifetime. IR Image from NRLMRY But the big question remains: where is this storm heading? There are three camps that exist as of this time, as highlighted in the image above. The first scenario is an early recurvature to the northeast. This scenario is the least damaging as it would bring Phanfone away from Okinawa and the rest of Japan. It is also the least likely scenario out of the three based on the latest data from the computer models. This will rely on the Subtropical Ridge over the North Pacific being really weak and we are not seeing that at this point in time. The second scenario is basically the most conservative as it is the midpoint between the two opposing forecasts. This scenario suggests that Phanfone will still recurve to the north and east early enough that it doesn’t go as far west as Okinawa. However, this scenario is not sparing Mainland Japan. Based on the latest data and analysis, it would seem that this scenario is highly plausible. The Joint Typhoon Warning Center is suggesting this scenario based on their latest forecast (10/03 00 UTC), albeit slightly east. The third and final scenario is the westernmost solution out of the three. This is showing a track which will take Phanfone towards the Ryukyu Islands and eventually recurve to the northeast. This is the most dangerous and highly concerning forecast as it showing Phanfone directly raking the Japanese Islands as a very strong typhoon. This scenario is also supported by the two highly-renowned weather computer models (ECWMF and the GFS). The Japan Meteorological Agency is east of this solution. The uncertainty and divergence among the different computer models lie in the atmospheric circulations high above the surface. The progression of the mid-latitude troughs (or extra-tropical lows) is crucial to the recurvature of Phanfone. A faster progression will lead to an early recurvature and less impact for Japan. While we rarely get technical with our analysis here at Western Pacific Weather, another possible reason is called the Pacific-North American Teleconnection aka PNA. This PNA is simply-put, at atmospheric circulation in the Northern Hemisphere with wide-reaching effects for both the Pacific and the North American Region, hence the name. To make the analysis short, the inevitable track of Phanfone is possibly being influenced by the status of the PNA Index. Right now, the most plausible solution is also the most conservative one. However, that does not mean that residents in Okinawa should relax. In fact, the recent changes in the forecast should make our readers in that region even more curious and engaged. As always, we encourage everyone to consult their country’s official weather agency for the latest tracks and warnings. Hopefully, we will come into more agreement with regard to Phanfone’s forecast track in the coming days. For a more in-depth explanation with WxCaster PAT’s analysis, you may visit our Facebook Page. Stay safe!