Hurricane Adrian continued to move westward off the coast of Mexico on Thursday, a day after rapidly intensifying to become the first hurricane in the eastern Pacific region this year, the National Hurricane Center said.
The storm was moving across the Pacific and moving away from the west coast of Mexico Thursday, the Hurricane Center said. It had maximum sustained winds of 85mph, slightly above the 74mph threshold that makes a storm a hurricane. Tropical disturbances are given a name when they encompass sustained winds of at least 39 mph
As of mid-Thursday, there were no coastal watches or warnings in effect for Adrian, according to the National Weather Service, although the Hurricane Center said Adrian could continue to strengthen later in the day.
A separate tropical storm was expected to form further south in the Pacific, Hurricane Center She said. As of Thursday afternoon, that system was about 150 miles southeast of Acapulco, Mexico, and moving parallel to the country’s southern coast. Certain tropical warnings and watches related to that storm system were in effect for part of the southwest coast of the country.
The center said the system, which had maximum sustained winds of 35 mph, could develop into a hurricane by Friday night. Heavy rains were reported on the coasts of Oaxaca and Guerrero, and up to seven inches of rain were expected throughout southern Mexico, where there was the possibility of flash flooding.
By noon Thursday, Adrian was 445 miles west-southwest of Manzanillo, Mexico, at a speed of seven miles per hour
Maria Torres, a meteorologist at the National Hurricane Center in Miami, said Wednesday that Adrian will keep the same general heading through Thursday and should make a west-northwest turn on Friday. The hurricane does not appear to pose an immediate threat to land and would remain in open waters, she said.
But Ms Torres said people living along Mexico’s coastal areas should monitor the storm and watch updates from their local weather offices, “because it can create rip currents and dangerous beach conditions.”
When a tropical storm forms in the Atlantic or Pacific Oceans, it generally moves westward, meaning Atlantic storms usually pose a greater threat to North America. When a storm builds near land in the Pacific, it can bring damaging winds and rain before moving out to sea.
However, an air mass can sometimes block a storm, pushing it north or northeast toward the Baja California Peninsula and other parts of Mexico’s west coast. Occasionally, a storm can move further north, as was the case with last year’s post-tropical Cyclone Kay, which brought damaging winds and heavy rains to Southern California.
Some Pacific storms even move over US territory; In 1997, Hurricane Nora made landfall in Baja California before moving inland and reaching Arizona as a tropical storm.
The hurricane season in the eastern Pacific began May 15, two weeks before the start of the Atlantic season. Both seasons run until November 30th.
Complicating things in the Pacific this year is the likely development of El Niño, the weather pattern that can have wide-ranging effects around the globe.
In the Pacific Ocean, El Niño reduces changes in wind speed and direction known as wind shear. Wind shear instability normally helps prevent storm formation, so a reduction increases the chance of storms. (In the Atlantic Ocean, El Niño has the opposite effect.)
On average, the eastern Pacific hurricane season generates 15 named storms; eight typically reach hurricane strength and four become major hurricanes with winds reaching 111 mph. In the central Pacific, four to five named storms develop or move through the basin each year.
There is consensus among scientists that hurricanes are getting more powerful due to climate change. While there may be no more named storms overall, the likelihood of major hurricanes is increasing.
Climate change is also affecting the amount of rain storms can produce. In a warming world, the air can hold more moisture, meaning a named storm can bring more precipitation, as did Hurricane Harvey in Texas in 2017, when some areas received more than 40 inches of rain in less than 48 hours.
The researchers also found that the storms have slowed down in recent decades. When a storm slows down on water, it increases the amount of moisture the storm can absorb. As the storm slows down over land, the amount of rain falling on a single location increases. In 2019, Hurricane Dorian slowed to a crawl over the northwestern Bahamas, resulting in a total rainfall of 22.84 inches in Hope Town.