Detecting Linear Precipitation Bands with AI for Early Alerts: Achieving 100% Detection Rate in August 2025

According to a survey by the Japan Meteorological Agency (JMA), extreme rainfall events of more than 50 mm per hour are on the rise. These heavy downpours increase the risk of disasters such as landslides and flooding, making them increasingly dangerous¹. In particular, linear rainbands can cause prolonged, intense rainfall over the same area, often leading to severe disasters that significantly impact daily life. However, due to their highly localized nature, it is difficult to predict exactly when and where they will occur. At Weathernews, we consider these characteristics when determining how we deliver information.

In this article, we'll share how Weathernews uses independently analyzed data to detect linear rainbands and deliver critical weather information to our users.

Early Detection of Linear Rainbands with AI

The JMA recorded nine linear rainbands inAugust 2025². The JMA typically issues warnings about potential heavy rainfall roughly half a day in advance and releases "Significant Heavy Rainfall Information" based on observed rainfall patterns and warning thresholds³. However, we recognized the need for even earlier detection.

While the JMA provides official announcements, Weathernews not only delivers that information to users but also operates its own early detection system for linear rainbands to notify them of heavy rain risks as quickly as possible.

Linear rainbands form when updrafts repeatedly occur in the same location and warm, moist air continues to flow into the area. In addition to the JMA’s AMeDAS and radar data, Weathernews also utilizes its own observation network and weather reports from users to create proprietary analysis data.

Our AI analyzes this data to identify critical warning signs: humidity convergence, significant temperature variations, specific wind patterns, and the formation of extremely heavy rainfall in linear patterns. This allows us to detect developing linear rainbands much earlier than traditional methods.

"Linear Rainband Alarm" Alerts Issued Earlier than the JMA

We deliver our independently analyzed linear rainband data to 3,833 companies and organizations⁴ through "weathernews for Business⁵" via our Linear Rainband Alarm feature. When our system detects a rainband within a 5 km radius of a user's location, we immediately send a push notification alerting them to take immediate caution.

The chart below compares the timing of the JMA's official announcements with our Linear Rainband Alarm notifications for the period from August 6 to 12.

Our verification of all JMA-announced cases in August showed impressive results: Weathernews detected every single rainband earlier than official announcements, achieving a 100% early detection rate. This means our service consistently notified users of impending danger ahead of the JMA's "Significant Heavy Rainfall Information," giving them valuable extra time to take protective measures against severe rain hazards.

Broadcasting Expert Information via Weathernews LiVE

Beyond our corporate services, we also deliver critical information about linear rainband risks through our 24/7 live weather program, Weathernews LiVE.

The power of live broadcasting allows us to respond instantly to rapidly changing weather conditions. With seamless coordination between our forecast center and production team, we can quickly deliver expert insights to help keep viewers safe.

We provide comprehensive coverage across three critical stages:

Before occurrence: Our system identifies early warning signs, and we explain forecast areas and probabilities in detail. We focus heavily on concrete preparedness actions, especially for potentially dangerous nighttime events.

During occurrence: Experienced meteorologists provide in-depth analysis, covering rainfall duration, total accumulation, and potential disaster risks like landslides and river flooding. We integrate live radar data and field reports directly into our broadcasts.

After occurrence: We break down the scientific causes behind each event and share practical guidance for those in evacuation shelters, helping communities better prepare for future disasters.

But we go beyond just delivering expert information. Weathernews LiVE is committed to improving disaster literacy by explaining complex meteorological concepts in everyday language and building an engaged community. Our goal is to help viewers maintain strong disaster preparedness awareness as part of their daily lives.

This blog has highlighted our comprehensive approach to delivering timely linear rainband information. While the JMA provides valuable nationwide warnings roughly half a day in advance, we've developed systems that can forecast potential rainband occurrence within the next 12 hours, giving people crucial extra time to prepare.

Looking ahead, we remain committed to leveraging cutting-edge technology and AI to provide even earlier and more accurate information about linear rainband development and risks. Our mission is simple: to help users protect their daily lives, secure their workplaces, and ultimately, save lives.