Tropical Storm Philippe, a weather system that was swirling in the Atlantic Ocean on Monday, was poised to cause flooding and dump several inches of rain across Antigua and Barbuda through Tuesday, forecasters said.
The National Hurricane Center estimated that Philippe had maximum sustained winds of 50 mph, with higher gusts. The storm was about 20 miles east of Barbuda and was moving northwest at 7 mph, the hurricane center said in an advisory Monday.
Heavy rains were expected to continue through Tuesday, with a risk of flooding in portions of the Leeward Islands.
The center of Philippe is forecast to pass near, or just northeast of, the northern Leeward Islands through Monday night, producing heaving rain across some parts, the center said.
The government of Antigua upgraded its tropical storm watch to a warning Monday; a warning was already in effect for Barbuda, the hurricane center said. Up to 6 inches of rain was predicted, forecasters said, and they warned that the rain may cause isolated to scattered flash floods. The rest of the Leeward Islands may see up to 4 inches of rain from the storm.
The Barbados Meteorological Services discontinued severe thunderstorm warnings Monday afternoon, adding that the island had registered 2-3 inches of rain and numerous lighting strikes, at an average rate of 4 strikes per minute, on Monday afternoon.
While the storm’s strength was not expected to change over the next day or so, it could begin to intensify more significantly by the middle of the week.
The Atlantic hurricane season started June 1, and runs through Nov. 30.
In late May, the National Oceanic and Atmospheric Administration predicted that there would be 12 to 17 named storms this year, a “near-normal” amount. On Aug. 10, NOAA officials revised their estimate upward, to 14 to 21 named storms.
There were 14 named storms last year, after two extremely busy Atlantic hurricane seasons in which forecasters ran out of names and had to resort to backup lists. (A record 30 named storms took place in 2020.)
This year features an El Niño pattern, which started in June. The intermittent climate phenomenon can have wide-ranging effects on weather around the world, and it typically impedes the number of Atlantic hurricanes.
In the Atlantic, El Niño increases the amount of wind shear, or the change in wind speed and direction from the ocean or land surface into the atmosphere. Hurricanes need a calm environment to form, and the instability caused by increased wind shear makes those conditions less likely.
At the same time, this year’s higher sea surface temperatures pose a number of threats, including the ability to supercharge storms. That unusual confluence of factors has made it more difficult to predict storms.
There is consensus among scientists that hurricanes are becoming more powerful because of climate change. Although there might not be more named storms overall, the likelihood of major hurricanes is increasing.
Climate change is also affecting the amount of rain that storms can produce.
In a warming world, the air can hold more moisture, which means a named storm can hold and produce more rainfall, as Hurricane Harvey did in Texas in 2017, when some areas received more than 40 inches of rain in less than 48 hours.
Researchers have also found that over the past few decades storms have slowed down, sitting over areas for longer.
When a storm slows down over water, it can absorb more moisture. When the storm slows over land, it can release more rain over a single location. In 2019, for example, Hurricane Dorian slowed to a crawl over the northwestern Bahamas, resulting in a total rainfall of 22.84 inches in Hope Town during the storm.
This article originally appeared in The New York Times.