Typhoon Shanshan Intensifies: Strong Winds and Heavy Rain Forecasted for Japan

2024/08/24 05:30 Weather News

As of 3:00 AM on August 24 (Saturday), Typhoon No. 10 (Shanshan) is moving northwest from the Mariana Islands.

▼ Typhoon No. 10 3:00 AM, August 24 (Saturday)
Center Position Mariana Islands
Size Category //
Strength Category //
Movement Northwest 10 km/h
Central Pressure 985 hPa
Maximum Wind Speed 30 m/s (near the center)
Maximum Gust Speed 45 m/s
» Latest Typhoon Information

Expected to Develop to “Very Strong” Power at Peak

Typhoon No. 10 has been unable to develop due to the influence of dry air, but it is expected to start developing again as it moves north, and is predicted to become a “very strong” typhoon at its peak. Before making landfall in Japan, it is expected to return to a “strong” typhoon, but caution is necessary.

If we look at the forecast path, Typhoon No. 10 is expected to change to a westerly course after moving north for a while, and is anticipated to move northwest to around 30 degrees north latitude. It is becoming increasingly likely that it will make landfall somewhere from Kyushu to Kanto between Tuesday, August 27, and Wednesday, August 28. After passing through, it could continue moving north-northeast, crossing the Japanese archipelago while acquiring the characteristics of an extratropical cyclone, and heading towards northern Japan.

There are concerns that strong winds and heavy rain will affect areas close to the typhoon’s path. Additionally, even areas further east away from the path may experience strong winds and rough weather, so caution is advised.

Reference: Numerical simulation results of the forecast paths calculated by meteorological agencies from around the world.

Each thin line in this figure represents the results of numerical simulations calculated by meteorological agencies around the world. These calculations of the low-pressure center using an ensemble forecasting method will introduce intentional errors in the initial values to assess the reliability of forecasts, among other things.

When comparing these, there is a general tendency for the typhoon to turn off the coast of Shikoku and head towards northern Japan, suggesting that it is almost certain to impact Japan. Considering the forecasting period, the variability is relatively small; however, due to its shallow angle approaching land, it’s difficult to narrow down the regions that will be affected, and paths passing to the west of Kinki to those around Kanto are both possibilities.

Even slight differences in the predicted path can make a big difference in the areas affected and the degree of impact, so it is necessary to pay close attention to forecast changes. As time passes, errors are expected to decrease, so please stay tuned for further information.

Probability of Entering the Typhoon’s Strong Wind Area

The following prefectures have a probability of 31% or more of entering the typhoon’s strong wind area within the next five days. (Japan Meteorological Agency)
・51-60%
Gifu Prefecture, Aichi Prefecture, Mie Prefecture, Nara Prefecture, Wakayama Prefecture
・41-50%
Toyama Prefecture, Ishikawa Prefecture, Fukui Prefecture, Nagano Prefecture, Shizuoka Prefecture, Shiga Prefecture, Kyoto Prefecture, Osaka Prefecture, Hyogo Prefecture, Tokushima Prefecture, Kochi Prefecture
・31-40%
Fukushima Prefecture, Gunma Prefecture, Saitama Prefecture, Tokyo Metropolis, Kanagawa Prefecture, Niigata Prefecture, Yamanashi Prefecture, Okayama Prefecture, Kagawa Prefecture, Ehime Prefecture

From August 27 (Tuesday) to August 29 (Thursday), there may be announcements for storm warnings, wave warnings, high tide warnings, and heavy rain warnings. There is a possibility that the impact on transportation will expand, with operational suspensions on railways and road closures on expressways becoming more likely.

Concerns of Heavy Rain Before Typhoon Approaches

From this weekend, an upper-level trough will remain stagnant over the west side of the Japanese archipelago, facilitating the inflow of moist air circulating around the periphery of the Pacific High. This will activate the frontal activities stagnating near Honshu.

Moreover, due to the addition of moist air from Typhoon No. 10, the atmospheric conditions are expected to become unstable, resulting in heavy rain starting before the typhoon approaches. Please pay attention to weather information even if you are far from the typhoon.
» Detailed Weekly Weather Forecast
» Radar Wind Mode (Wind Flow)

The sixth Typhoon of the Month

This is the third typhoon since Typhoon No. 9 formed on the 19th (Monday) of this week. It is the sixth typhoon to have formed this month.

Looking at the average number of typhoons formed historically, August sees an average of 5.7, making it the period of the year with the most typhoons. With six typhoons already forming this year, it seems that we are at or above the average pace.

As we transition from summer to autumn, the number of typhoons approaching near Honshu is expected to increase, marking the onset of the full-fledged typhoon season, so please prepare for typhoon and heavy rain measures.
» Radar Satellite Cloud Imagery Mode

Name of the Typhoon

The names of typhoons are prepared in advance by member countries of the international organization “Typhoon Committee,” with 140 names allocated in the order they occur.

The name of Typhoon No. 10 “Shanshan” was proposed by Hong Kong, deriving from the name of a girl.
» Radar Typhoon Mode

Reference Materials