Cyclone Nisarga, the equivalent of a tropical storm Tuesday, churns toward the western coast of India. (RAMMB/CIRA)

Less than three weeks after hosting Category 5-equivalent super cyclonic storm Amphan, the Indian Ocean is again blistering with storm activity. A significant tropical cyclone is likely to develop in the Arabian Sea by Wednesday evening, slated to bring strong winds and flooding rains to Mumbai. It comes as the city is gripped by the coronavirus crisis, with hospitals overflowing and local infrastructure overwhelmed.

The financial center, home to 18 million people, has logged roughly 1,000 deaths and more than 40,000 covid-19 infections. The city is set to be slammed by Cyclonic Storm Nisarga on Wednesday into Thursday, which the India Meteorological Department predicts will be accompanied by a storm surge of up to three to six feet and winds gusting up to 75 mph.


The India Meteorological Department's forecast for Nisarga's evolution. (IMD)

The cyclone, equivalent to a tropical storm as of late Tuesday local time, is forecast to intensify overnight into Wednesday morning as it churns north and draws nearer to the coast.

Some environmental parameters — such as toasty sea surface temperatures and efficient upper-level exhaust of its previously ingested air — favor more-dramatic strengthening. But those aspects are offset by strong winds in the upper atmosphere that serve to disrupt the cyclone’s structure, effectively capping the storm’s propensity for growth as it flirts with hurricane-equivalent force.

In its update Tuesday afternoon, the India Meteorological Department noted “the system has been further well organized in the last three hours,” with winds estimated sustained at 45 mph.

“The sea condition is high to very high around the system’s center,” wrote the department.

The storm is being steered around a ridge of high pressure anchored to the south. Clockwise flow around the high-pressure ridge will propel Nisarga to the north-northeast, in the direction of northern Maharashtra and the southern coast of Gujarat.

If a six-foot storm surge is realized, as in the predicted worst-case scenario, some parts of Mumbai could experience inundation. While a surge of around six feet is at the high end of a list of possibilities, the India Meteorological Department states the most likely outcome will be a surge in Mumbai of 1.5 to 3.5 feet.

Rainfall will also have a serious impact, with six- to 10-inch amounts likely in Mumbai and some localized totals of around 14 inches. Moist flow from the southeast will bring periods of downpours down the coast, while the system’s remnants could drop four to seven inches along a swath as far inland as northern Madhya Pradesh or Uttar Pradesh.


The European model depicts hefty rain totals likely to fall along the west coast of India into the greater Mumbai area and inland through Friday. (WeatherBell)

Though Mumbai is a coastal city, powerful cyclones are relatively rare there.

The timing of the cyclone could not have come at a worse time for Mumbai. With over 40,000 cases, the densely packed city has emerged as the epicenter of the coronavirus outbreak in the country. The health-care system is already under strain, and some hospitals have had to turn away patients as they run out of beds.

During the past month, the state government has raced to construct temporary health-care facilities in empty spaces to house the steady increase of patients, many of whom are at risk. Over 150 patients at one such facility were moved, as the structure was not deemed strong enough to withstand the high winds expected in the storm.

In a televised address, Uddhav Thackeray, the state’s chief minister, urged residents to stay indoors for two days and brace for possible power cuts. He said the state was being “tested” first by the virus and now the cyclone.

Niha Masih reported from Delhi.

Clarification: This story has been clarified to indicate that June tropical cyclone landfalls are rare, though not unheard of, in Mumbai.