Cyclone Phyan

Meteorological history

Late on 4 November 2009, the Joint Typhoon Warning Center (JTWC) reported that an area of convection had started to deepen around a poorly organized and elongated low level circulation center about 340 km (210 mi), to the southwest of Colombo in Sri Lanka. The low level circulation center was located in a region of upper level divergence which was providing a good channel for outflow, however it was also located in an area of moderate to high levels of vertical wind shear. During the next couple of days the disturbance gradually developed whilst moving around a subtropical ridge of pressure before the disturbance moved onshore in India during 7 November and became more marked as it moved out into the warm waters of the Arabian Sea during the next day. Early on 9 November, as a Tropical Cyclone Formation Alert was issued by the JTWC; the India Meteorological Department (IMD) reported that the disturbance had become a depression and designated it as Depression ARB 03 as multiple bands of deep convection had started to consolidate around the now well-defined low-level circulation center.

Later on 9 November, the JTWC reported that the depression had intensified into a tropical cyclone, designating it as 04A, with wind speeds equivalent to a tropical storm as organized deep convection increased around a consolidating low level circulation center. Early the next day the IMD reported that the depression had intensified into a Deep Depression as convection organized further. The IMD further reported later that day that the deep depression had reached its peak windspeeds of 65 km/h (40 mph) 3-min sustained, which made it a Cyclonic storm with it being named as Phyan whilst located about 500 km (310miles) to the southwest of Mumbai as it moved into an area of high vertical wind shear. Early on 11 November the JTWC reported that Phyan had reached its peak intensity of 95 km/h (60 mph), before the Cyclone made landfall in Maharashtra between Alibagh and Mumbai later that morning. Later that day as the low level circulation center had rapidly detached from the deep convection the JTWC issued their final advisory whilst the IMD reported that Phyan had weakened into a depression before downgrading it to a well marked area of low pressure early on 12 November.