Why Do Typhoon Track and Intensity Forecasts Vary Across Different Meteorological Agencies?
TyphoonSays·防御问答 · Typhoon knowledge · 更新 at 2026-08-03
Differences in Initial Data and Observation Methods
Typhoons form over vast oceans, which are often "blind spots" for meteorological observations. Although we have weather satellites, radar, and buoys, we cannot deploy observation points as densely as we do on land. Meteorological agencies in different countries rely on different sources of initial data: some primarily depend on their own satellite imagery analysis, while others incorporate data from hurricane hunter aircraft reconnaissance or shared data from neighboring countries.
This is similar to several doctors diagnosing a patient: if one only reviews an X-ray while another also considers blood test results, their preliminary diagnoses will naturally differ slightly. These minor errors in initial data are amplified by computer models, leading to divergent forecast tracks. Furthermore, different agencies use varying technical methods to determine the typhoon's center location (such as cloud pattern analysis or microwave imaging), which directly affects the accuracy of the initial position.
Different Logics in Numerical Prediction Models
Modern typhoon forecasting relies heavily on "Numerical Weather Prediction (NWP) models" run by supercomputers. Major global meteorological centers have their own proprietary models, such as China's CMA-TYM, the US GFS, Europe's ECMWF, and Japan's GSM. These models differ in their mathematical physical equations, parameterization schemes, and understanding of atmospheric dynamics.
- Model biases vary: Some models are more sensitive to the strength of the subtropical high, while others react more strongly to changes in deep ocean temperatures.
- Update frequencies differ: Some agencies update forecasts multiple times a day, while others release them at fixed times. This means the "latest" forecast seen by the public may be based on atmospheric states from different moments.
Therefore, when a typhoon is in a region with complex steering flows and strong interactions with surrounding weather systems, calculation results from different models tend to diverge significantly, resulting in the "wide variety" of forecast tracks seen across different countries.
Differences in Intensity Classification Standards
Besides track differences, people are often confused why the same typhoon is classified as a "Severe Typhoon" by one agency but merely a "Typhoon" by another. This is because there is no globally unified standard for classifying tropical cyclones.
The China Meteorological Administration (CMA) adopts the national standard "Grades of Tropical Cyclones," classifying them based on the maximum 2-minute average wind speed near the center. In contrast, the Joint Typhoon Warning Center (JTWC) typically uses the 1-minute average wind speed, while the Japan Meteorological Agency (JMA) uses the 10-minute average wind speed. Due to these different averaging periods, even if the actual wind force is identical, the converted intensity levels will differ. For example, 1-minute average wind speeds are generally higher than 10-minute averages, which can lead to different intensity assessments by the US and Japan at the same time.
It is important to note that typhoon warning signals (such as Red, Orange, Yellow, and Blue) and the corresponding regulations for school and work suspensions vary by location. Always refer to the announcements issued by your local government. When referencing data from international agencies, the public should prioritize localized warning information released by their national meteorological department to make correct disaster prevention decisions.
Real-time typhoon tracks can be queried at TyphoonSays (taifengshuo.com)
This article is typhoonsay's original copy content, and the local policy standards are based on the local government's latest release.