Hurricane Patricia's 215 mph Winds: A Warning Shot Across Our Bow
The Eastern Pacific's Hurricane Patricia--rated the strongest hurricane ever recorded in the Western Hemisphere with 200 mph sustained winds on October 23, 2015--was actually much stronger, with 215 mph winds, said the National Hurricane Center (NHC) last week, after completing a detailed post-season review. An Air Force hurricane hunter aircraft measured a surface wind of 209 mph in Patricia at 0600 UTC October 23 using a Stepped-Frequency Microwave Radiometer (SFMR); this was the highest surface wind ever measured in a tropical cyclone, worldwide, since the technology was introduced in the mid-1980s. A 207 mph surface wind was measured by the SFMR instrument on a NOAA hurricane hunter aircraft during an eyewall penetration about twelve hours later, at 1732 UTC. In between those two times, there were no measurements by the Hurricane Hunters, but satellite imagery showed that the hurricane improved in organization up until about 1200 UTC, with the eye warming and the eyewall cloud tops cooling. NHC thus assigned Patricia a peak intensity of 215 mph winds with a central pressure of 872 mb at that time. Hurricane Patricia's 215 mph winds officially tie it with the Northwest Pacific's Super Typhoon Nancy of 1961 for strongest winds of any tropical cyclone in world history, and Patricia's lowest pressure of 872 mb makes it the second most intense tropical cyclone in world history, behind the 870 mb measured in the Northwest Pacific's Super Typhoon Tip of 1979 (Tip's top sustained winds of "only" 190 mph were not as high as Patricia's, since Tip was a large, sprawling storm that did not have a tiny concentrated area of extreme eyewall winds.) Note that that the maximum sustained winds estimated in typhoons like Nancy during the 1940s to 1960s are considered by hurricane experts to be too strong; a re-analysis of Super Typhoon Nancy would likely find that its winds were considerably slower than 215 mph. I regard Patricia as unmatched for the strongest winds of any tropical cyclone in recorded history. It is possible that previous hurricanes where hurricane hunter flights were not available, such as the Category 5 1935 Labor Day hurricane that devastated the Florida Keys, had peak winds on par with Patricia, though.
Figure 1. Hurricane Patricia as seen by the MODIS instrument on NASA's Terra spacecraft at 1:30 pm EDT (17:30 UTC) October 23, 2015. At the time, Patricia had 205 mph sustained surface winds and a central pressure of 878 mb. Patricia had peaked at 215 mph sustained winds and a central pressure of 872 mb six hours previously. Image credit: NASA.
Figure 2. Category 5 Hurricane Patricia as seen from the International Space Station on Friday afternoon, October 23, 2015. Image credit: Commander Scott Kelly.
Patricia the fastest- to second-fastest-intensifying Western Hemisphere hurricane on record
In the 24-hour period ending at 2 am EDT (06 UTC) October 23, 2015, Patricia's central pressure dropped an astonishing 95 mb, to 886 mb, and the winds increased by 120 mph, to 205 mph, making Patricia the fastest-intensifying hurricane (by winds) and second-fastest intensifying hurricane (by pressure) ever observed in the Western Hemisphere. The record pressure drop in 24 hours is 97 mb for Hurricane Wilma of 2005 (between 1200 UTC 18 October - 1200 UTC 19 October), and the previous record intensification of winds in 24 hours was 110 mph for Wilma, according to the official NHC report for the storm. Patricia's intensification rate was very close to the WMO-recognized world record for fastest-intensifying tropical cyclone: 100 millibars in just under 24 hours by Super Typhoon Forrest in the Northwest Pacific in 1983.
Another remarkable record: a NOAA reconnaissance aircraft flying through the eye at 17:33 UTC October 23, several hours after the time of estimated peak intensity, measured a maximum 700-mb temperature of 32.2°C (90°F). This is the warmest 700-mb eye temperature ever measured in a tropical cyclone world-wide. The height of the 700 mb level was 2043 meters (about 6700 feet) above sea level, which is the lowest such height ever observed in the tropics in the Western Hemisphere. A more typical height for the 700 mb pressure level is 3180 meters (10,430 feet.) Since hurricane penetrations are done by flying the aircraft at a constant pressure altitude of 10,000 feet (in other words, flying so that the aircraft is continuously experiencing a pressure of approximately 700 mb), the aircraft had to make a steep descent while traversing the eyewall in order to stay at the 700 mb pressure level, and emerged into the eye at an altitude as measured by radar that was below 7,000 feet. The steep descent caused trouble with the SFMR readings, which had to be re-calibrated after the flight to ensure their accuracy. Thanks go to Rich Henning of the NOAA Hurricane Hunters for this info.
Figure 3. Ten-day averaged sea surface temperatures (SSTs) from 1948 - 2015 during mid-October over the waters of the Eastern Pacific off the coast of Mexico between 13°-17°N and 100°-105°W (inset box) traversed by Hurricane Patricia during its rapid intensification period October 20 - 23, 2015. SSTs were at their highest values on record in this region in 2015. Image credit: NHC.
Patricia's record intensification fueled by record-warm ocean waters
Hurricane Patricia's remarkable intensification was made possible by very light wind shear and record warm ocean waters. During its rapid intensification phase, Patricia tracked over a large expanse of anomalously warm waters with sea surface temperatures (SSTs) of 30.5°-31°C (87°-88°F). These were the highest SSTs ever observed over this region in mid-October.
Figure 4. Wind (black) and surface pressure (red) from the afternoon NOAA hurricane hunter flight on October 23, 2015 into Hurricane Patricia, off the Pacific coast of Mexico. The aircraft measured peak winds at their flight level of 10,000 feet of up to 145 knots (165 mph). The winds showed a double maximum in both sides of the eyewall as the plane flew crossed the calm eye, indicating that an eyewall replacement cycle was likely underway. This eyewall replacement cycle helped Patricia become the fastest-weakening hurricane ever observed. The eye was a tiny 6 miles in diameter at this time. Image credit: Levi Cowan, tropicaltidbits.com.
Patricia the fastest-weakening Western Hemisphere hurricane on record
As Patricia approached the rugged Mexican coast, the storm began to weaken due to two major factors: interaction with land, and an eyewall replacement cycle. Patricia’s central pressure is estimated to have risen a remarkable 54 mb in the five hours prior to landfall. No other tropical cyclone over water in either the Atlantic or Eastern North Pacific historical record has been observed to weaken so quickly. Patricia made landfall near 23 UTC October 23 along a sparsely populated part of the coast of southwestern Mexico at Playa Cuixmala, about 50 miles west-northwest of Manzanillo, as a category 4 hurricane with 150 mph winds and an estimated landfall pressure of 932 millibars. This makes Patricia the strongest hurricane on record to make landfall in Mexico, eclipsing the October 1959 Manzanillo hurricane (recently reassessed to have made landfall at category 4 intensity), and Hurricane Madeline in 1976. Note, though, that reliable records for extreme landfalling Mexican hurricanes extend back only to 1988. Only two direct deaths were reported from Patricia's landfall, but damage was a steep $325 million.
Hurricane Hunters measure near-record updrafts and downdrafts
NOAA's hurricane hunter aircraft N43RF ("Miss Piggy") encountered significant turbulence (3 Gs of acceleration in the cockpit) both inbound and outbound from the 1733 UTC October 23 eye fix into Patricia. The aircraft measured a peak updraft of +26.1 m/s (58 mph) and a downdraft of -16.2 m/s (36 mph). Thanks go to Rich Henning of the NOAA Hurricane Hunters for this info. To my knowledge, this is the strongest downdraft ever recorded in a hurricane by the NOAA P-3 Orion Hurricane Hunter aircraft since they began service in 1976. According to an email I received from hurricane scientist Sim Aberson at NOAA's Hurricane Research Division, the only higher updraft ever measured by the P-3s is probably the 31 m/s (69 mph) reading in Category 5 Hurricane Felix of 2007 in the Caribbean. The extreme turbulence associated with this updraft (and the downdraft of 11 m/s or 25 mph that immediately preceded it) forced the aircraft to abort the mission and return to base. The only two other NOAA hurricane hunter flights with comparable extreme updrafts and downdrafts were into Hurricane Emily of 1987 and Hurricane Hugo of 1989. I was the Flight Meteorologist on both flights. Flying at 15,000 feet in Category 3 Hurricane Emily as it was making landfall in Hispaniola, we observed 3 Gs of acceleration during an updraft of +23.9 m/s (53 mph) that was accompanied by a downdraft of -9.6 m/s (21 mph). During this penetration through the eyewall, pilot Jim Gunoe was forced to roll the plane about 20 degrees in order to stop a dangerous aerodynamic flutter that developed in the wings. We then aborted the mission due to the extreme turbulence. Two years later, flying at 1,500 feet into the eyewall of Hurricane Hugo, we hit 5.7 Gs of acceleration as we measured a +21 m/s updraft and -8 m/s downdraft. An engine flamed out during this extreme turbulence, and the pilot was able to pull us out of a steep descent just 880 feet above the waves as we entered the eye. This flight was the subject of a detailed story that I wrote and a 45-minute long video by the TV series, Air Crash Investigation that aired on the National Geographic Channel last year (complete with CGI graphics and actors playing the roles of the crew.) The video is available on YouTube.
The Air Force Hurricane Hunters have encountered similar extreme updrafts and downdrafts in some of their flights into Category 5 hurricanes, such as into Hurricane Wilma of 2005 when it was at peak intensity, but the vertical wind data taken from the Air Force C-130 hurricane hunter aircraft are not routinely analyzed post-flight.
Figure 5. Infrared VIIRS images of Hurricane Patricia near peak strength: 215 mph winds and a central pressure of 872 mb. Image credit: Dan Lindsey, NOAA.
Another record: worst NHC intensity forecast ever made in the Eastern Pacific
As one might expect when trying to forecast the intensity of a hurricane that smashed all previous intensification records in mind-boggling fashion, NHC's intensity forecasts for Patricia were way off. The average error in NHC 48-hour intensity forecasts was 66 mph, compared to an average forecast error of 16 mph for all Eastern Pacific forecasts made during the 2010 - 2014 period. Several of NHC's forecasts for Patricia had intensity errors through 48 hours that were the highest on record since NHC took over warning responsibility in the eastern North Pacific basin in 1988: up to 120 mph off, beating the record 115 mph error for a forecast made in Hurricane Linda of 1997. None of the intensity models anticipated the degree to which Patricia would intensify, nor how quickly it would occur, and the official intensity forecasts for Patricia from NHC severely underestimated the rapid intensification that occurred and failed to explicitly show rapid intensification until it was actually occurring. It should be noted, however, that a key model used to make intensity forecasts--the SHIPS Rapid Intensity (RI) guidance--was temporarily unavailable before Patricia’s rapid intensification began due to missing satellite inputs. Having these data in real time would likely have resulted in better intensity forecasts than those that were made.
Figure 6. Expected change in Atlantic Category 4 and 5 hurricanes per decade expected by the year 2100, according to Knutson et al. (2013), "Dynamical Downscaling Projections of 21st Century Atlantic Hurricane Activity: CMIP3 and CMIP5 Model-based Scenarios." This research used the latest generation of climate models from the 2013 IPCC report, and found "marginally significant" increases in Atlantic Category 4 and 5 hurricanes of 39% - 45% by 2100.
Commentary: Patricia was a warning shot across our bow
Consider, now, if the bad intensity forecasts for Hurricane Patricia had been made for a Hurricane Patricia clone that had ended up making landfall in a heavily populated area such as Miami, Galveston/Houston, Tampa, or New Orleans, but without the hurricane weakening dramatically at landfall. A 15-mile diameter area of 215 mph winds--EF5 tornado speeds--would have caused near-total destruction. Since the storm would have been significantly under-warned for, a full evacuation might not have been completed, resulting in one of the deadliest hurricane tragedies in human history. The ten-year drought in major hurricane landfalls in the U.S. is going to end someday, and an onslaught of major hurricanes like we experienced in 2004 - 2005--seven landfalls by major hurricanes in two years--could happen again. As I discussed in my 2013 post, Hurricanes and Climate Change: Huge Dangers, Huge Unknowns, the consensus among hurricane experts is that climate change is likely to bring an increase in the number of high-end hurricanes like Patricia. Now that ocean temperatures are considerably warmer than they were a few decades ago, the maximum potential intensity a hurricane can reach is higher, and we should expect to see a few Patricias sprinkled among the inevitable phalanxes of major hurricanes that will assault our shores in the coming decades.
Progress is being made in improving hurricane intensity forecasts, thanks to the 10-year Hurricane Forecast Improvement Project (HFIP), which aims to reduce hurricane track and intensity errors by 50% by 2019. Unless some dramatic breakthroughs in intensity forecasting occur in the next three years, though, we are going to fall short of that goal. But if we really want to crack the intensity forecast puzzle, we should be spending far more on hurricane research than we do--something I've been calling for repeatedly over the past ten years. The National Science Board, in a report issued in 2006, called for an increase of $300 million per year in hurricane research funding. That's more than ten times the annual spending on hurricane research of $20 - $25 million per year that we've averaged over the past ten years. The 24 members of the National Science Board are appointed by the President of the United States, and make budget recommendations for the National Science Foundation (NSF). They are not prone to make frivolous budgetary recommendations, and realize that the specter of a Patricia-like nightmare storm hitting with insufficient warning is one to take seriously. Such a large but sensible investment can lead to significantly better intensity forecasts. Will we wait again to see unprecedented mayhem like during Katrina in 2005 and Sandy in 2012 before responding to the need to spend more money on better hurricane forecasts? Consider Patricia a shot across our bow--we have been warned (again.) It is up to us to respond.
Hurricane Patricia Cat-5 fix
Check out this incredible footage of our flight through the eye of Category 5 Hurricane #Patricia off the coast of Mexico. The video was taken from the flight station of #NOAA43 (#NOAA P-3) and provided by Lt. Cmdr. Scott Price (the missions's Aircraft Commander). The video begins inside the eyewall: note that the intense rain and wind combination makes it impossible to see the nose of the aircraft just a few feet away. At 37 seconds, the crew enters the eye of the #Hurricane, where the violent sea-state below becomes visible. Note that due to the storm's incredibly steep gradient, the aircraft is pitched downward as the aircraft descends closer to the ocean. At 57 seconds, the curved eyewall on the opposite side of this very small eye becomes apparent. After a couple of slight turns requested by the Flight Meteorologist to report the exact center of the storm, the crew turns right to avoid the worst of the eyewall. At ~2 minutes into the video, the aircraft reaches the opposite eyewall where the crew loses visibility once again.Posted by The NOAA Hurricane Hunters on Thursday, November 5, 2015
Video 1. Incredible footage the flight of NOAA hurricane hunter aircraft N43RF through the eye of Category 5 Hurricane Patricia on the afternoon of October 23, 2015, when the storm was near peak strength, with 205 mph sustained surface winds and a central pressure of 878 mb. Lt. Cmdr. Scott Price (the mission's Aircraft Commander) made the video using a GoPro camera. The video begins inside the eyewall: note that the intense rain and wind combination makes it impossible to see the nose of the aircraft just a few feet away. Since the aircraft is flying perpendicular to the wind in order to find the center, the rainfall is blowing from left to right in front of the pilot's vision. At 37 seconds, the crew enters the eye of the hurricane, where the violent sea-state below becomes visible. Note that due to the storms incredibly steep pressure gradient, the aircraft is pitched downward as the aircraft descends closer to the ocean, in order to keep flying at a constant pressure altitude. At 57 seconds, the curved eyewall on the opposite side of this very small eye becomes apparent. After a couple of slight turns requested by the Flight Meteorologist to report the exact center of the storm, the crew turns right to avoid the worst of the eyewall. At ~2 minutes into the video, the aircraft reaches the opposite eyewall where the crew loses visibility once again. Posted by The NOAA Hurricane Hunters on Thursday, November 5, 2015.
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Dr. Masters co-founded wunderground in 1995. He flew with the NOAA Hurricane Hunters from 1986-1990. Co-blogging with him: Bob Henson, @bhensonweather
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