Storm Rapidly Intensifying in the Gulf of Mexico

Could we be seeing the first major hurricane to make landfall in the United States in almost 12 years? It is possible. Over the last 12 hours or so, Tropical Storm Harvey has been undergoing a great deal of changes, and now is more likely to be at least a minimal hurricane, or even stronger by the time it makes landfall in Texas.

Yesterday, Harvey’s overall structure was elongated and asymmetrical, which was hampering its development. This morning, the structure has changed with the storm taking on a more circular or symmetrical shape, which is what it needed in order to have a chance of strengthening.

With the shear that has been affecting it slackening off, and the very warm waters that have existed in the Gulf of Mexico. Harvey has been also moving at a relatively slow pace, and is expected to slow down even more by the time it makes landfall along the Texas Coast on Saturday morning. Forecast models have become more bullish on Harvey’s intensification.

Ironically, it is 25 years ago today that Hurricane Andrew, a Category Five Hurricane, made landfall and tore across South Florida. If you recall, Andrew was a storm that had been written off. The situation with Harvey has been somewhat similar. On Sunday, the storm was battling hostile environmental conditions in the Central Caribbean, and was downgraded to a tropical wave. Then, its remnants battled their way across the Yucatan Peninsula.

Overnight on Wednesday, Hurricane Hunter aircraft flew into Harvey, and found a 16 millibar pressure drop over a span of 8 hours, which is an average of two millibars per hour. All of this means that Harvey is now undergoing a rapid intensification phase. As of the 7:00 AM CDT Advisory from the National Hurricane Center, the minimum central pressure in Harvey had fallen to 986 millibars, or 29.12 inches, which meets the threshold for a Category One Hurricane on the Saffir-Simpson Scale.

Winds in the storm have increased to 60 miles per hour, and Harvey could become a hurricane later today. The NHC forecast discussion from 4:00 AM CDT this morning indicated that Harvey is likely to become a Category One Hurricane with 85 mile per hour winds within 48 hours before making landfall along the Texas coast. Some intensity model forecasts have Harvey becoming a Category Two system. Regardless of how strong Harvey gets, the big fear is going to be the rainfall.

Many parts of Texas have already received a ton of rain this summer. Same goes for Louisiana, which is also under threat, especially in the Southwestern region. The most recent advisory indicates that much of the Texas coast could see at least 15 inches of rainfall with some isolated areas receiving as much as 25 inches. Further inland areas could still see up to 9 inches. There are two basic tracks that the models are showing for Harvey.

As of 6z, the GFS (American) and CMC (Canadian) indicated a Harvey track that pushed it into Southern Texas, and heading westward toward San Antonio. Meanwhile, the Euro and the NAVGEM had the storm coming up the Texas coast, lingering for a bit, and then moving out into the Gulf again toward Louisiana. The last time a significant hurricane made landfall in Texas was in September 2008 when Category Two Hurricane Ike came ashore.

The last time a major hurricane made landfall in the United States was in October 2005 when Hurricane Wilma, which became the strongest storm ever in the Atlantic Basin with 882 millibars, came ashore near Naples, Florida, and roared through the Sunshine State and causing severe damage to the Florida Gold Coast including Fort Lauderdale. Residents along the Texas and Louisiana coast from Brownsville to Lake Charles should closely monitor the situation with Harvey.