Tag Archives: Tropical Storm Harvery

Remnants of Tropical Storm Harvey About to Move Over Gulf of Mexico

The remnants of former Tropical Storm Harvey are about to move over the southern Gulf of Mexico.  At 2:00 p.m. EDT on Tuesday the center of the remnants of Tropical Storm Harvey was located at latitude 20.3°N and longitude 89.8°W which put it about 45 miles (75 km) south-southwest of Merida, Mexico.  It was moving toward the northwest at 15 m.p.h.  The maximum sustained wind speed was 30 m.p.h. (50 km/h) and there were wind gusts to 40 m.p.h. (65 km/h).  The minimum surface pressure was 1010 mb.

A broad area of low pressure that contained the remnants of former Tropical Storm Harvey moved across the Yucatan peninsula on Tuesday.  Thin bands of showers were rotating around the broad area of low pressure over land.  Several broken bands of thunderstorms were evident on the northern and northeastern periphery of the low pressure system.  There were several smaller centers rotating around inside the larger area of low pressure, but the circulation appeared to consolidating around a center near Merida.  A few thunderstorms were forming near that center as it neared the coast.

The National Hurricane Center indicated that there is a nearly 100% chance that the low pressure system will strengthen into a tropical cyclone again once it moves over the Gulf of Mexico.  The Sea Surface Temperature (SST) in the southern Gulf of Mexico is near 31°C.  An upper level low over the northwestern Gulf of Mexico was producing some vertical shear over the top of the surface low.  The upper low is forecast to move north and weaken.  An upper level ridge over the northwestern Caribbean Sea is forecast to move over the western Gulf of Mexico.  The upper ridge will produce southerly winds which will cause some vertical wind shear.  However, those winds are expected to be weak enough to allow for intensification.  The southerly winds could actually enhance upper level divergence to the north of the low pressure system in a day or two.

Given the large size of the low pressure system and the lack of a well defined center of circulation, the system will likely start to intensify slowly.  The rate of intensification will increase once a well defined center forms.  A period of very rapid intensification could occur later this week because of very warm SSTs and little vertical wind shear.  The area of low pressure could become a tropical depression within 12 hours.  It is likely to be a tropical storm on Wednesday.  The system has a good chance of becoming a hurricane over the western Gulf of Mexico.  If the system moves slowly and rapid intensification occurs, it could become a major hurricane.

A ridge in the middle troposphere near Florida is steering the low pressure system toward the northwest and a general northwesterly motion is forecast for the next several days.  There will be more uncertainty about the future track until a well developed center of circulation forms.  However, it seems likely that this system will move toward the coast of Texas.  The system could slow and/or turn more toward the north when it nears the coast.  It has the potential to become a significant hurricane by the time it reaches the coast.  It could bring strong gusty winds, which could cause a significant storm surge at the coast.  If the system moves slowly, it could also drop very heavy rain, which would create flash floods.