Dr. Masters co-founded wunderground in 1995. He flew with the NOAA Hurricane Hunters from 1986-1990. Co-blogging with him: Bob Henson, @bhensonweather
By: Dr. Jeff Masters , 6:12 PM GMT on July 17, 2005
Posted: 2pm EDT July 17
The 1:15pm EDT Hurricane Hunter report indicated the winds and pressure inside Emily had not changed much. However, the report stated: "Very strong convection with hail outbound thru north eyewall." As a former hurricane hunter, I can speculate on a more detailed version of what happened:
"As our C-130 airplane crossed out of the eye into the north eyewall, the plane hit updrafts and downdrafts of 30 - 40 mph and the turbulence severe enough to throw loose objects around the cabin. The clattering sound of hail on the metal skin of the airplane was loud enough to make your ears ring, and the plane will probably need a new paint job after this ride."
Hail is rare in hurricanes, due to their warm nature. Hail can has cut short several Hurricane Hunter missions in the past--the hail damages engines and instruments, and will strip the paint off the wings. And you can bet if they're mentioning "very strong convection", they're probably getting accelerations of 2 - 3 g's in severe turbulence. The Hurricane Hunters are definitely earning their money today.
Posted: 10:30am Sunday July 17
Hurricane Emily is a little weaker this morning, after briefly flirting with Category 5 status last night. The National Hurricane Center never officially upgraded it to a Cat 5, but noted that about 3 GMT (11pm EDT), when Emily had its lowest pressure of 929 mb, it may have briefly attained Category 5 status. The 10am EDT Hurricane Hunter flight found a minimum pressure of 946 mb, up 18 mb from last night. The winds have fallen some, from 155 mph to 150 mph. The eye is no longer as distinct, the Central Dense Overcast (CDO) is not circular, and upper-level outflow on the SW side looks restricted. Emily is undergoing an eyewall replacement cycle, and it appears that this has also made the storm more vulnerable to some shearing. As Steve Gregory noted in his blog, there is more shear than one typically finds over a major hurricane right now--10 knots.
Emily will probably not have time to make it to Category 5, if the last eyewall replacement cycle it went through is any indication. When that cycle started, Emily's pressure rose for about 8 hours, leveled off for 4 hours, then started falling again. A full 24 hours elapsed before she regained her former intensity. The current cycle began at about 11pm EDT, and it appear to be following a similar trend. Emily's pressure rose for 8 hours, and has leveled off the past four hours. Satellite images from the past hour show some improved organization, and re-intensification is probably starting to occur. If it again takes a full 24 hours for Emily to regain her previous strength, she may approach Cat 5 again late tonight. However, Emily will be close to landfall at midnight tonight, and will begin pulling in dry air off of the Yucatan Peninsula late this afternoon. This may disrupt the hurricane enough to prevent it from reaching Category 5. I expect Emily will hit Mexico tonight as a strong Category 4 hurricane.
Emily will hit the resort towns of Cozumel and Cancun hard. When Hurricane Gilbert hit this area in 1988 as a Category 5 storm with 170 mph winds, it took the 125-foot Cuban ship Portachernera and cast it up on the beach at Cancun, where it remained for months.
Image credit:The St. Petersburg Times
Damage from Gilbert to Cozumel alone was $80 million. Damage from Emily will probably be much higher, even though is it a much smaller storm and not as strong. The reason is because the Cancun/Cozumel resort areas had only 8,000 hotel rooms back in 1988, but now have over 50,000. A tremendous amount of development has occurred in the past 17 years. A mass evacuation of the tourists in the area is currently underway, and the towering beach front hotels will stand vacant to confront Emily's wind and seas tonight.
After crossing the Yucatan, Emily will emerge into the Gulf of Mexico as a much weakened Category 2 or even Category 1 storm. Emily is relatively small as hurricanes go, and the passage over the Yucatan should severely disrupt her inner core. Waters over the Gulf are warm--about 30C--but the depth of warm waters is not as deep as the western Caribbean. Thus, the total heat energy available to the storm is probably not enough to support a Category 4 hurricane. I expect Emily will make its second landfall south of the Texas/Mexican border as a Category 2 hurricane. With this intensity, and if the current track forecast verifies, Brownsville would only receive tropical storm force winds. As usual, it must be emphasized that a hurricane's intensity is extremely hard to predict, and Emily could easily be a Category 1 or Category 3 hurricane at its second landfall. Hurricane track forecasts the past 10 years have had a median error of 200 miles for a 72-hour forecast. The official NHC 72-hour forecast puts the landfall point about 100 miles south of Brownsville. So, a landfall 100 miles north of Brownsville--or 300 miles south of Brownsville--should not come as a surprise.
One more note--I do read all of the comments posted, and answer the ones I can do quickly. In many cases, I don't know the answer, or need to perform fair bit of research to confirm my knowledge, so I am unable to post as many follow-ups as I'd like. Last night, I was unable to post from my home up here near Ann Arbor, Michigan. A thunderstorm spawned from the remnants of Hurricane Dennis knocked out power to my neighborhood for 12 hours!
Dr. Jeff Masters
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