By Allison A. Wing and Chia-Ying Lee
Hurricane Patricia is expected to make landfall on the Southwest coast of Mexico this afternoon and evening as an extremely dangerous Category 5 hurricane. As of 1 p.m. EDT today (Friday, Oct. 23), the National Hurricane Center estimated Hurricane Patricia’s maximum wind speed at 200 mph, which makes Patricia the strongest hurricane ever observed in the National Hurricane Center’s area of responsibility (the North Atlantic and eastern North Pacific).
Unlike many storms across the globe, where we rely on satellites to estimate their intensity, NOAA and U.S. Air Force reconnaissance aircraft have been flying through Patricia to obtain direct observations, which allow us to make more precise and confident estimates of its intensity. The minimum central pressure of 880 mb estimated by aircraft data is also the lowest ever observed in either the Atlantic or eastern Pacific.
Patricia intensified incredibly rapidly over the last day and a half, exploding from a tropical storm with wind speeds of 63 mph at 8 p.m. EDT Wednesday night to a Category 5 hurricane with wind speeds of 160 mph only 24 hours later, followed by strengthening to the current intensity of 200 mph by this morning. The images below are enhanced images from a polar orbiting satellite about 24 hours apart, showing the dramatic change in Patricia’s visual appearance from a somewhat disorganized tropical storm to a more symmetric hurricane with a clear eye.
To put in perspective how unusual this is, this rate of intensification is the greatest 24-hour increase in intensity observed in the satellite era (since 1981); this rate was also observed in eastern Pacific Hurricane Linda in 1997.
Was this rapid intensification accurately predicted? The below graph shows, in the black line, the observed dramatic increase in Hurricane Patricia’s maximum wind speeds (in knots). The colored lines show three different forecast models, and in the gray, the official forecasts from the National Hurricane Center, initialized at different times over the last few days.
While most of the models predicted strengthening, they all underestimated how quickly Patricia would strengthen and how strong the wind speeds would become. The National Hurricane Center explicitly forecast rapid intensification in their advisory at 11 p.m. EDT on Wednesday night and in subsequent advisories yesterday, noting the very favorable environment (low vertical wind shear, very humid air, very warm sea surface temperatures and high upper ocean heat content). The sea surface temperatures in the eastern Pacific are currently significantly warmer than average because of the strong El Niño event that is occurring. However, it is very challenging to forecast rapid intensification, and indeed, the explosive strengthening of Patricia was nearly unprecedented in the observed record.
Currently, the National Hurricane Center is forecasting Patricia to approximately maintain its strength before it makes landfall as a Category 5 storm, which is potentially catastrophic for the communities on the southwest coast of Mexico, including the resort town of Puerto Vallarta. Patricia has the potential to be the strongest tropical cyclone at landfall on record.
Devastating storm surge may occur along the coast, but severe impacts may also occur away from the coast, as the National Hurricane Center notes that “very heavy rainfall is likely to cause life-threatening flash floods and mud slides.” After landfall, Patricia is expected to weaken quickly as it moves over the mountainous terrain of Southwest Mexico.
Here in the United States, we often only pay attention to the hurricanes in the Atlantic Ocean. But even in an average year, the Atlantic makes up only ~10 percent of global tropical cyclone activity. In an El Niño year (like this year), the relative contribution of the Atlantic is even less, since there tend to be fewer hurricanes in the Atlantic, but more and stronger hurricanes in the Pacific.
This year has been a very active tropical cyclone season in the Pacific, fueled by one of the strongest El Niños on record. Right now, there are two other tropical cyclones active in the Pacific, Hurricane Olaf and Typhoon Champi.
Allison A. Wing is a National Science Foundation postdoctoral research fellow at Lamont-Doherty Earth Observatory. Chia-Ying Lee is a postdoctoral research scientist at the International Research Institute for Climate and Society. Their research on tropical cyclones is a component of the Columbia Initiative on Extreme Weather and Climate.