The Japan Meteorological Agency said a system malfunction prevented the issuance of immediate forecasts and occurrence information for a line-shaped rain band.
This failure is critical because these specific alerts are designed to provide warnings two to three hours before a dangerous weather event occurs [3]. Without this lead time, residents in high-risk areas have significantly less time to seek shelter or evacuate before torrential rains hit.
The malfunction affected a forecast scheduled for 5:30 p.m. on June 2, 2026 [1]. The intended target area for the alert was the western part of Kochi Prefecture [2].
Agency officials said the malfunction on June 3, 2026. While the agency acknowledged the failure, it has not yet provided a timeline for when the system will be fully recovered. In the interim, the agency is asking the public to monitor the "General Weather Explanation Information" available on its official website for updates.
Takahashi Kenichi, head of the Weather Monitoring & Warning Center, said the failure during a press briefing. He said the gravity of the technical error and the need for a thorough investigation into the cause.
"We recognize that this must not happen," Takahashi said. "We must reflect deeply on why this occurred and what we must do to ensure it is not repeated. We will take this seriously and respond accordingly."
The agency said it must reflect on the cause of the glitch to prevent a recurrence. This incident occurs as the agency manages its specialized alerting services, which aim to provide precise, short-term warnings for the most dangerous types of precipitation patterns.
“We recognize that this must not happen”
The inability to issue 'immediate forecasts' represents a significant gap in Japan's disaster prevention infrastructure. Because line-shaped rain bands cause sudden, extreme flooding and landslides, the loss of a two-to-three-hour warning window increases the risk to human life and property in affected regions like Kochi Prefecture.
