IMD Mumbai chief Bikram Singh explains rain alert criteria and forecasting technology
The India Meteorological Department’s (IMD) Regional Meteorological Centre (RMC) in Colaba, Mumbai, has upgraded its forecasting systems to achieve an 80 to 90 percent accuracy rate, according to RMC head Bikram Singh. Speaking on July 4, 2026, Singh explained how the centre uses advanced technology to issue critical rain alerts that help citizens plan their days and assist city authorities in making safety decisions during the monsoon season.
Singh clarified the specific criteria used for issuing weather alerts. A red alert is only issued when the city is expected to experience more than 204 mm of rain within a 24-hour period. If the forecast predicts 200 mm of rainfall, the RMC issues an orange alert instead. Singh noted that red alerts prompt major administrative changes, such as authorities deciding whether to close schools and businesses to prevent accidents.
Addressing public questions about clear skies during designated red alerts, Singh explained that these alerts are often issued as precautionary measures. Heavy rains may have occurred overnight, or weather models may have indicated extremely heavy rainfall. He stated that while the system has an 80 to 90 percent accuracy rate, it is a machine-based process where issues can occasionally arise.
Over the past decade, the RMC in Colaba has significantly upgraded its monitoring systems. Previously, observations were limited to a range of 50 to 100 km, which restricted fast predictions. Today, the city features multiple automatic monitoring stations that transmit data updates every 15 minutes. This network allows the RMC to issue immediate nowcast warnings for weather expected within a few hours.
The centre relies on a combination of automatic weather stations, e-radars, and satellites to monitor rainfall intensity and generate nowcasts. For longer-term planning, the RMC uses numerical weather prediction to forecast weather conditions for the upcoming days, enabling both the public and local authorities to plan their weeks.
Singh also addressed regional rainfall variations. While Mumbai's Colaba and Santacruz stations recorded surplus rainfalls of 11 percent and 18 percent respectively, other regions in Maharashtra have faced deficits. The Konkan region, for instance, experienced a 25 percent deficit, though it is expected to head toward normal levels in the coming weeks.
