09.20.17

Hurricane Maria Slams Puerto Rico After Becoming Strongest Storm of 2017

Posted in Storm Track, Storm History, Storm Facts, Storm Aftermath, Storm Preparation, GWC News, Storm Warning, Storm Safety, Hurricane Intensity, Hurricane Records, Tracking the Tropics, Model Forecasts at 10:10 pm by gmachos

While Jose meandered its way up the Eastern Seaboard this week, and created rough surf and dangerous rip currents along the Jersey Shore, Maria exploded from being a tropical depression to a monster Category Five Hurricane within a span of just 56 hours. During that time, the pressure in the tropical system dropped some 83 millibars, or approximately 2.49 inches of Hg (Mercury).

Maria was not only a classic case of a Cape Verde storm, but also a perfect study in the phenomenon known as rapid intensification. This kind of development in tropical systems is usually where a fledging tropical cyclone such as a depression, or a weak tropical storm gets into an area very favorable for development with an abundance of warm water, and very little in the way of wind shear, which stifles thunderstorm formation that is essential for intensification.

What Maria did was essentially “bomb out”. The storm dropped approximately 1.5 millibars per hour. This is the kind of scenario that many people following weather closely in New Jersey, New York, Pennsylvania, and Connecticut usually see during the winter with a major snowstorm, blizzard, or nor’easter. For example, the powerful storm that paralyzed the Mid-Atlantic and Northeast on March 14th of this year. It ultimately had a barometric pressure of 29.15 inches, or 987 millibars, or equivalent to a Category One Hurricane.

This particular winter storm bombed out. The pressure drop with the powerful March 14th snowstorm was approximately 38 millibars in about 18 hours, which was classic bombogenesis. Maria as well as Irma and Jose did much of the same thing in the Central and Western Atlantic before they all moved into the Northeastern Caribbean. Harvey also did much of the same thing in the Gulf of Mexico before it made landfall as a Category Four Hurricane over Rockport, Texas. Katrina, Rita, and Wilma did much of the same thing in 2005.

Many of the classic powerful Cape Verde storms that reach Category Four and Category Five strength on the Saffir-Simpson Scale experience this explosive development. The hurricane has the classic buzzsaw look with the well defined outflow and banding along with a well defined eye. With Maria, the eye feature was very small. While Irma’s eye ranged from 23 to 25 nautical miles wide in diameter, Maria’s was only about half of that at 11 nautical miles. Storms with smaller eyes, usually are much more powerful.

Like I had mentioned in a previous post to the blog, the eye of a hurricane and the actual storm itself is like a figure skater, conserving angular momentum. The tighter the eye, the faster the air is rotating counterclockwise around it. Hurricanes and even extratropical systems have two kinds of motion, rotational and translational. As a result of the rotation, or spin, these storms develop angular momentum, which like kinetic momentum, needs to be conserved. Smaller storms such as Hurricane Andrew (1992), Hurricane Camille (1969), and the Labor Day Hurricane of 1935, were classic cases of small, but potent storms. All of them would end up being the only landfalling Category Five storms in the United States.

Maria devastated the island of Dominica as a Category Five storm with 160 mph winds. Then, as the storm headed toward the Virgin Islands and Puerto Rico, Maria intensified more to become the most powerful hurricane yet in 2017 in terms of pressure by dropping to 909 millibars, which was four millibars lower than Irma was at her peak (913 millibars). Winds grew to 175 miles per hour, but never increased to the point where they were as high as Irma’s were. The hurricane crushed the island of St. Croix in the Virgin Islands, and then became the most powerful storm to strike Puerto Rico since 1932 even though it had weakened to just below the Category Five threshold on Wednesday.

The mountains of Puerto Rico, which go up to about 4,000 feet in places, and are not as high as those in Hispaniola (7,000 feet) and Cuba (10,000 feet), still managed to weaken Maria with orographic lifting to 140 miles per hour, and then 110 miles per hour. Hurricane Maria now is taking aim at the Dominican Republic, and threatens the beaches such as Punta Cana on its Northern Coast. Both Puerto Rico and the Dominican Republic did take some hits from Irma, but not a direct hit like Puerto Rico did with Maria earlier on Wednesday. The storm completely knocked out power on Puerto Rico.

Looking at the model ensembles earlier today, there is agreement that the storm will move north and near the Outer Banks of North Carolina within the next five days. By next Thursday, the storm is projected by both the GFS and Euro to be in the area of New York City although these two solutions slightly differ. Keep in mind that the model projections for Maria to be in the area of New York City by this time next week is premature, but it is something for residents of the Mid-Atlantic to keep in the back of their minds. Even the NHC’s five day forecast is off an average by about 160 miles, which is about the difference between a storm coming ashore in Cape May, New Jersey, or in New York City. Residents along the East Coast of the United States should closely monitor the progress of this still dangerous storm.

As of the 8:00 PM Advisory from the National Hurricane Center in Miami, Florida, Hurricane Maria was located some 55 miles to the East-Northeast of Punta Cana on the northern coast of the Dominican Republic. Maria is moving steadily to the Northwest at 12 miles per hour. Maximum sustained winds remain at 110 miles per hour, which is just below Category Three or major hurricane status. Wind gusts continue to be at 130 miles per hour. Minimum central pressure has risen to 958 millibars, or 28.29 inches. Hurricane force winds extend some 60 miles from the center while tropical storm force winds reach out some 150 miles. The eye’s diameter expanded to 36 nautical miles.

Reading the most recent NHC forecast discussion from about 5:00 PM EDT indicates that Maria will re-strengthen to a major hurricane within 24 hours, and should remain at Category Three strength through 72 hours. From there, Hurricane Maria is anticipated to wind down to a Category One Hurricane by the end of five days. Hurricaneville will continue to monitor this storm, and post updates to both its Facebook and twitter feeds, and try to provide a daily update to the blog.

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