Incredibly strong Hurricane Patricia is barreling ashore on the Southwest coast of Mexico near La Manzanilla as a Category 5 storm. At 5 pm EDT Friday, NHC put Patricia's intensity at 190 mph winds. Early on Friday morning, Patricia reached a remarkable intensity of 200 mph sustained winds, which the storm maintained for 12 hours. These are the highest reliably-measured surface winds on record for a tropical cyclone, anywhere on the Earth. At 2:30 pm Friday afternoon, October 23, 2015, a NOAA hurricane hunter aircraft measured a central pressure of 879 mb--the lowest pressure ever measured in a hurricane in the Western Hemisphere. The previous strongest Eastern Pacific hurricane was Hurricane Linda of 1997, with a pressure of 902 mb (estimated from satellite imagery), and the strongest Atlantic hurricane on record was Hurricane Wilma of 2005, with 882 mb. Patricia does not beat the record-lowest pressure in the Western Pacific, though, which is held by Super Typhoon Tip of 1979: 870 mb.
Figure 1. MODIS image of Hurricane Patricia as seen from NASA's Aqua satellite on Friday, October 23, 2015. At the time, Patricia was a Category 5 storm with 200 mph winds. Image credit: NASA.
Figure 2. Hurricane Patricia as seen from the International Space Station on Friday afternoon, October 23, 2015. Image credit: Commander Scott Kelly.
Figure 3. 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. The eye was a tiny 6 miles in diameter at this time. Image credit: Levi Cowan, tropicaltidbits.com.
Patricia weakening at landfall Late-afternoon data from a NOAA hurricane hunter aircraft in Patricia indicates that the hurricane is forming concentric eyewalls, presaging an eyewall replacement cycle, where the inner eyewall collapses and is replaced by an outer eyewall that forms out of a spiral band. This process typically weakens the peak winds of the hurricane by up to 20 mph, but spreads out the highest winds of the storm over a larger area. This process typically reduces the wind damage from a storm, but makes a larger storm surge, leading to more storm surge damage.
Patricia the fastest-intensifying Western Hemisphere hurricane on record Patricia's central pressure dropped an astonishing 100 mb in 24 hours, making it the fastest-intensifying hurricane ever observed in the Western Hemisphere. Patricia's pressure at 5 am EDT Thursday, October 22, 2015 was 980 mb, and was 880 mb at 5 am EDT Friday. The previous record was a drop of 97 mb in 24 hours for Hurricane Wilma of 2005 (between 1200 UTC 18 October - 1200 UTC 19 October), according to the official NHC report for the storm. Patricia's intensification rate was very close to the WMO-recognized world record for fasting-intensifying tropical cyclone: 100 millibars in just under 24 hours by Super Typhoon Forrest in the Northwest Pacific in 1983.
Patricia is estimated to have intensified 85 knots (100 mph) in 24 hours, from a tropical storm to a Category 5 hurricane. In the Eastern Pacific, Hurricane Linda of 1997 is the only storm on record to have intensified at this rate. The Atlantic's record holder for largest wind increase in 24 hours is held by Hurricane Wilma of 2005, which intensified from a 60-knot tropical storm to a 150-knot Category 5 hurricane--an increase of 90 knots (105 mph). Air Force reconnaissance observations indicated that the eye of Wilma contracted to a diameter of 2 n mi during this time; this is the smallest eye known to National Hurricane Center (NHC) staff. Patricia's eye diameter was 8 miles at it's peak strength.
Figure 5. Maximum Potential Hurricane Intensity (MPHI) for the Eastern Pacific on October 23, 2015, calculated according to a method developed by Dr. Kerry Emanuel. The MPHI for the waters traversed by Hurricane Patricia was less than 880 mb. Few storms ever approach their maximum theoretical intensity, but Hurricane Patricia did--reaching 879 mb at 2 pm EDT October 23, according to measurements from the Hurricane Hunters. The Maximum Potential Hurricane Intensity is maximized as the sea surface temperature rises and as the atmosphere grows more unstable (cold, dry air aloft combined with warm, moist air near the surface.) Image credit: COLA/IGES.
Patricia the third strongest tropical cyclone in history (by wind) Patricia's 200 mph sustained winds make it the 3rd strongest tropical cyclone in world history (by 1-minute averaged wind speed.) Officially, here are the strongest tropical cyclones in world history, according to the Joint Typhoon Warning Center and the National Hurricane Center (using 1-minute averaged sustained winds):
However, it is now recognized (Black 1992) that the maximum sustained winds estimated for typhoons during the 1940s to 1960s were too strong. The strongest reliably measured tropical cyclones were both 10 mph weaker than Patricia, with 190 mph winds—the Western Pacific's Super Typhoon Tip of 1979, and the Atlantic's Hurricane Allen of 1980. Both storms had a hurricane hunter aircraft inside of them to measure their top winds. Haiyan's winds were estimated using only satellite images, making its intensity estimate of lower confidence.
Dr. Hugh Willoughby, former head of NOAA's Hurricane Research Division, had this to say about the winds measured in Super Typhoon Nancy and the other high-end typhoons from this list from the 1960s:
"I would not take the winds seriously because reconnaissance meteorologists estimated them visually. A decade later when I flew with the VW-1 hurricane hunters, we had the same Doppler system used to measure the winds of Typhoon Nancy. It tracked the aircraft motion relative to the (possibly moving) sea surface. It couldn't get a coherent signal in high winds because the beam reflected from both the actual surface (whatever that is) and blowing spray. Visual estimates are dubious because the surface (under the eyewall!) is hard to see unless you are flying below cloud base (200-300 m) and also because appreciably above 115 mph, it's completely white with blowing spray. We used to think that we could estimate stronger winds from the decreasing coverage of slightly greenish patches where the spray was thinner. I now think that we were kidding ourselves. In those days the distinctions among wind gust, sustained one-minute winds, etc., were less well defined than they are now. So we may never know the 1960s reconnaissance data really means!"
Forecast for Patricia: Mexico at dire risk The coast of Southwest Mexico is at risk of tremendous damage from wind, storm surge, and flooding rains. The right front quadrant of the storm, near the town of La Manzanilla, can expect gigantic waves atop a devastating storm surge. In a Friday afternoon blog post, storm surge expect Dr. Hal Needham says he expects a storm surge of 16.5 ft (5 m), which will be accompanied by large, destructive waves. This would be the largest storm surge in the modern history of Western Mexico. Fortunately, hurricane-force winds are likely to miss the resort town of Puerto Vallarta, which lies on the weaker left side of the hurricane. In their 5 pm EDT Friday WInd Probability Forecast, NHC gave Puerto Vallarta a 19% chance of seeing hurricane-force winds of 74+ mph. However, the town of Manzanillo (population 100,000), on the right-front quadrant of Patricia, had a 49% chance of hurricane-force winds.
After landfall, Patricia will slam into very rugged terrain, triggering torrential rains with the risk of severe flooding and mudslides. The mountainous trek will shred Patricia’s low-level circulation quickly, but the hurricane’s upper-level circulation will proceed quickly northeastward, arriving near South Texas by Sunday. Models suggest that a nontropical or hybrid low-pressure center may develop near the upper-level center at that point. Patricia’s presence will exacerbate a multi-day rain/flood episode already under way across Texas, with widespread 4” - 8” rainfall amounts across the eastern half of the state expected between now and Monday. Localized totals well over a foot are quite possible.
iCyclone storm chasers in the path of Patricia Storm chaser Josh Morgerman, who intercepted Super Typhoon Haiyan at landfall in Tacloban in the Philippines, is aiming to be in the path of Hurricane Patricia's eye at landfall in Mexico. From the iCyclone Facebook page: "12:30 pm Friday (Jalisco): Erik and I noticed on satellite loops this morning that Hurricane PATRICIA's eye took a sharp hook to the right. We waited a little, then realized it was more than a wobble--so we loaded up the car and raced down Highway 200. Now we're in La Manzanilla, which we think could be very close to the cyclone's landfall point. But more adjustments might be needed. It's calm but raining very hard. La Manzanilla is an eerie ghost town. Everything is boarded up and shuttered. Still can't believe what's just offshore. You'd have to be a Cat-5 idiot not to be scared of it. Despite years and years of chase experience, I'm just in awe of this one." Live reports from the iCyclone team will be airing on The Weather Channel all day.