A potential threat posed by Tropical Storm Nicholas prompted the issuance of a Hurricane Watch for a portion of the Texas coast on Sunday. At 11:00 p.m. EDT on Sunday the center of Tropical Storm Nicholas was located at latitude 22.5°N and longitude 95.5°W which put it about 260 miles (415 km) south-southeast of the Mouth of the Rio Grande River. Nicholas was moving toward the north at 2 m.p.h. (3 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 1007 mb.
A Hurricane Watch was in effect for the portion of the coast from Port Aransas to Freeport, Texas. A Tropical Storm Warning was in effect for the portion of the coast from Barra el Mezquital, Mexico to High Island Texas. The Tropical Storm Warning included Corpus Christi and Galveston. A Tropical Storm Watch was in effect for the portion of the coast from High Island to Sabine Pass, Texas.
The circulation around Tropical Storm Nicholas was poorly organized. There was a broad center of circulation in the middle of Nicholas. Several smaller cyclonic circulations were revolving around inside the broad center. Many of the thunderstorms were occurring in bands in the northern half of Tropical Storm Nicholas. Bands in the southern half of Nicholas consisted primarily of showers and lower clouds. Winds to tropical storm force extended out 115 miles (185 km) in the northeastern quadrant of Tropical Storm Nicholas. The winds in the other parts of Nicholas’ circulation were blowing at less than tropical storm force.
Tropical Storm Nicholas will move through an environment favorable for intensification during the next 24 hours. Nicholas will move over water where the Sea Surface Temperatures are near 30˚C. It will move between and upper level low over northern Mexico and an upper level ridge over the northwestern Caribbean Sea. The upper low and ridge will produce southerly winds that will blow toward the top of Nicholas’ circulation. Those winds will cause some vertical wind shear, but the shear will not be strong enough to prevent intensification. The upper level low will move west and weaken on Monday. The upper level ridge will extend west over Tropical Storm Nicholas. When the ridge extends over Nicholas the upper level winds will weaken. When the upper level winds weaken, the vertical wind shear will decrease. Tropical Storm Nicholas will strengthen when that occurs. If a more well defined center develops in the middle of Nicholas, the it could strengthen more quickly. There is a chance that Nicholas could intensify to a hurricane later on Monday.
Tropical Storm Nicholas will move around the western side of a high pressure system that extends over the Gulf of Mexico. The high will steer Nicholas toward the north-northwest during the next 24 hours. On its anticipated track Tropical Storm Nicholas will approach the coast near the Mouth of the Rio Grande River on Monday. Nicholas will bring gusty winds and locally heavy rain to coastal areas of northern Mexico and east Texas on Monday. Tropical Storm Nicholas could also cause a storm surge of up to 7 feet (2 meters) along portions of the coast. It is possible that a new center of circulation could develop closer to the thunderstorms in the northern half of Tropical Storm Nicholas. If a new center develops farther to the north, that could increase the threat to northeastern Texas and western Louisiana.