User:Iune/Andhra Pradesh

Meteorological History
The origins of the 1977 Andhra Pradesh cyclone can be tracked to a weak tropical disturbance which was first noted on satellite imagery on the morning of 14 November while located roughly 520 km (320 mi) southwest of the Nicobar Islands. Traveling due west at 25 km/h (15 mph) along the southern periphery of the mid-tropospheric subtropical ridge, the disturbance steadily organized, with increased banding noted on satellite imagery. This increase in organization prompted the India Meteorological Department (IMD) to report that the disturbance had intensified into a deep depression later that morning, with the Joint Typhoon Warning Center (JTWC) issuing a Tropical Cyclone Formation Alert for the system at 1310 UTC that afternoon. At 0800 UTC on 15 November, the JTWC issued its first advisory on the system as satellite data indicated that the storm had continued to strengthen, with estimated one-minute sustained wind speeds of 75 km/h (45 mph).

While the system was initially developing, an upper tropospheric trough had formed over northern and central India and produced a break in the subtropical ridge. As the storm traveled towards this break in the ridge on 15 November, the mid-tropospheric anticyclone over the system weakened, reducing the storm's steering flow and causing the system to slow to a 7 km/h (5 mph) northwestwards movement. In addition, the divergent southwesterly flow produced by the trough resulted in the system beginning a period of rapid intensification. Early on 16 November, the system intensified into a Category 1-equivalent tropical cyclone on the Saffir-Simpson Hurricane Scale; an eye was observed on satellite imagery later that morning.

For the next two days, the tropical cyclone continued to steadily strengthen while traveling generally towards the north-northwest. During this time period, increased organization, such as tighter banding features and a progressively more distinct eye, were observed on satellite imagery. At 1030 UTC on 17 November, the ship Jagatswami reported winds of 190 km/h (120 mph) and a minimum barometric pressure of 941 hPa off the Indian coast. The next evening, the JTWC estimated that the system had attained its peak intensity as a Category 3-equivalent tropical cyclone, with one-minute sustained winds of 200 km/h (125 mph), while located roughly 140 km (85 mi) off the coast of Andhra Pradesh. Around this time, the IMD estimated that the system had three-minute sustained winds of 250 km/h (155 mph), which would classify the system as a modern-day super cyclonic storm, and a minimum barometric pressure of 919 hPa. This barometric pressure made the cyclone the most intense ever recorded in the North Indian Ocean at the time; the 1991 Bangladesh cyclone and the 1999 Odisha cyclone would both subsequently surpass the 1977 cyclone in terms of minimum barometric pressure.

As the cyclone approached the Indian coast, it accelerated to 17 km/h (10 mph) while slightly weakening from its peak intensity. The storm made landfall near Chirala, in the Prakasam district of central Andhra Pradesh, around 1100 UTC on 19 November with one-minute sustained winds of 195 km/h (120 mph). Moving northwards over flat agricultural lands, the storm slowly weakened, with the JTWC issuing its final warning at 2000 UTC that evening. The IMD continued tracking the system, reporting that it weakened into an area of low pressure on the evening of 20 November before dissipating over southeastern Madhya Pradesh and Odisha the next evening.