Tropical Storm Hanna Prompts Hurricane Warning for Texas

A strengthening Tropical Storm Hanna prompted the issuance of a Hurricane Warning for a portion of the coast of Texas on Friday afternoon.  At 5:00 p.m. EDT on Friday the center of Tropical Storm Hanna was located at latitude 27.3°N and longitude 94.3°W which put it about 195 miles (310 km) east of Corpus Christi, Texas.  Hanna was moving toward the west at 10 m.p.h. (16 km/h).  The maximum sustained wind speed was 50 m.p.h. (80 km/h) and there were wind gusts to 65 m.p.h. (105 km/h).  The minimum surface pressure was 999 mb.

A Hurricane Warning was in effect for the portion of the Texas coast from Baffin Bay to Mesquite Bay.  Tropical Storm Warnings were in effect for the portions of the coast from the Mouth of the Rio Grande River to Baffin Bay and from Mesquite Bay to San Luis Pass, Texas.

Tropical Storm Hanna exhibited much more organization on Friday afternoon.  A primary rainband wrapped around the southern and eastern sides of the center of Hanna.  The northern end of the rainband appeared to be wrapping around the rest of the center of circulation and an eye seemed to be forming.  Bands of showers and thunderstorms were revolving around the center of Tropical Storm Hanna.  Storms near the center were generating upper level divergence which was pumping mass away from the tropical storm.  The removal of mass was allowing the surface pressure to decrease.  Winds to tropical storm force extended out 60 miles (95 km) from the center for circulation.

Tropical Storm Hanna will move through an environment favorable for intensification during the next 18 hours.  Hanna will move over water where the Sea Surface Temperature is near 30°C.  It will move through a region where the upper level winds are weak and there will be little vertical wind shear.  Tropical Storm Hanna will continue to intensify.  If an eye and eyewall form completely, then Hanna could strengthen rapidly during the 6 to 12 hours prior to landfall.  Tropical Storm Hanna is very likely to intensify into a hurricane.

Tropical Storm Hanna will move south of a high pressure system that stretches across the southern U.S.  The high will steer Hanna toward the west during the next 24 hours.  On its anticipated track Tropical Storm Hanna will reach the coast of Texas near Corpus Christi during the middle of the day on Saturday.

Tropical Storm Hanna is very likely to be a hurricane when it makes landfall.  It will bring strong winds to the portion of the coast near where the eye makes landfall.  Strong winds blowing water toward the coast could create a storm surge of 6 to 8 feet (2 to 3 meters) near and to the north of where the eye makes landfall.

Elsewhere, a trade wind surge hit Tropical Storm Gonzalo from the northeast.  The surge caused increased low level wind shear and it brought drier air.  The increased shear and drier air caused Gonzalo to weaken.  At 5:00 p.m. EDT on Friday the center of Tropical Storm Gonzalo was located at latitude 10.0°N and 55.6°W which put it about 390 miles (625 km) east of the southern Windward Islands.  Gonzalo was moving toward the west at 18 m.p.h. (30 km/h).  The maximum sustained wind speed was 40 m.p.h. (65 km.h) and there were wind gusts to 50 m.p.h. (80 km/h).  The minimum surface pressure was 1008 mb.

Tropical Storm Warnings were in effect for Barbados, Tobago, Grenada, and St. Vincent and the Grenadines.