Hurricane Maria heads for catastrophic hit on Puerto Rico, St. Croix
By Bob Henson
19 September 2017
(Weather Underground) – After a direct hit on the small Lesser Antilles island of Dominica on Monday night, followed by a brief weakening, Hurricane Maria reintensified to Category 5 strength with winds of 160 mph on Tuesday morning. Maria will likely be a catastrophic Category 5 or high-end Category 4 storm when it hits the U.S. Virgin Islands and Puerto Rico on Wednesday morning. Preliminary reports out of Dominica indicate that Maria likely did catastrophic damage there. The northern eyewall of Maria also grazed the southwest corner of Guadaloupe Island on Monday night, and heavy damage was reported there. The core of the hurricane missed Montserrat, Saba, and St. Kitts and Nevis, but these islands have been experiencing sustained tropical storm-force winds and heavy rain squalls.Maria’s encounter with Dominica bruised the storm slightly, with the top winds falling to 155 mph and the central pressure rising from 924 mb to 934 mb between 11 pm Monday and 5 am Tuesday. This took the storm briefly down to a Category 4 rating. However, an Air Force hurricane hunter aircraft on Tuesday morning found a falling pressure and rising winds. Maria’s central pressure was down to 927 mb, and the winds were back up to 160 mph as of 11 am EDT Tuesday. Maria passed just east of Buoy 42060 late Tuesday morning; the buoy reported a pressure of 956 mb and sustained winds of 74 mph, gusting to 94 mph, at 11:10 am EDT Tuesday.Unfortunately for the islands in its path, Maria’s appearance on satellite imagery is truly spectacular, and the outer spiral bands of the hurricane are already lashing the Virgin Islands and Puerto Rico, as seen on long- range radar and Catherine Hope’s Webcam on St. Croix.The dreaded “pinhole” eye
Maria developed a tiny “pinhole” eye during its rapid intensification burst on Monday, with a diameter of 8 nautical miles (nm). The hurricane has maintained a small eye so far on Tuesday, with the diameter fluctuating between 7 nm and 10 nm (10 nm = 11.5 miles). Hurricanes that develop pinhole eyes often intensify into some of the strongest storms we observe, since they concentrate their wind energy around a narrow ring surrounding the tiny eye. These small eyes tend to be unstable, resulting in an eyewall replacement cycle (ERC) shortly after the pinhole eye is observed. […]
Short-term forecast for Maria
There is increasing confidence that Maria will reach St. Croix and Puerto Rico on Wednesday with catastrophic results. Now that Maria has regained Cat 5 intensity, there is nothing between the storm and these islands that would lead to a major drop in strength. In fact, conditions are just about as favorable as they can be for sustaining a Category 5 hurricane, and it’s not out of the question that Maria could become even stronger. Wind shear is predicted to stay very low (6 knots or less) for at least the next 48 hours, and Maria will be passing over very warm waters of 29-30°C (84-86°F). These warm waters are deep enough to provide substantial oceanic heat content (greater than 50 kilojoules per square centimeter), which will limit the potential of Maria’s fierce winds to churn up cooler water. If Maria embarks on an eyewall replacement cycle (EWRC) on Tuesday, the storm could drop to Category 4 strength by the time it approaches Puerto Rico. This process would spread Maria’s hurricane-force winds over a broader area, though. [more]
