Tropical Storm Nicholas to douse Texas coast with torrential rains

Tropical Storm Nicholas, which formed Sunday morning in the southwest Gulf of Mexico, is on track to be a prolonged and prodigious rainmaker for much of coastal Texas and Louisiana. At midday Sunday, a tropical storm warning extended along the western Gulf of Mexico coast from Barra el Mezquital, Mexico, to Port Aransas, Texas. A tropical storm watch extended northward to High Island, Texas, including Galveston Bay. Flash flood watches included the entire coastal region of Texas and southwest Louisiana, including Houston.

At 2 p.m. EDT Sunday, the center of newly formed Nicholas was located in the Bay of Campeche about 550 miles south of Houston. Nicholas was moving north-northwest at roughly 15 mph with top sustained winds of 40 mph, as confirmed by an Air Force hurricane-hunter flight on Sunday morning. Satellite imagery showed a disorganized but expanding field of showers and thunderstorms (convection), mostly toward the north side of Nicholas.

Forecast for Nicholas
Forecast models are consistent in bringing Nicholas on a gently arcing track from north-northwest to north-northeast over the next several days. By late Monday, Nicholas is expected to be paralleling the south Texas coast, and on Tuesday it is expected to slide ashore over the central Texas coast.

The main track question with Nicholas is how far east it goes on its path through the Gulf. Because of Nicholas’s angle of approach, a minor deviation in the projected track could make a major difference in Nicholas’s strength. Only a slight eastward departure could lead to a landfall further north, allowing more of Nicholas’s core circulation to remain over water and, which would give it more chance of strengthening. Sea surface temperatures over the northwest Gulf of around 30 degrees Celsius (86°F) and a very moist mid-level atmosphere (relative humidity around 80%) will support intensification through Monday, and wind shear of around 15 knots should not be too much of an impediment.

At midday Sunday, the National Hurricane Center (NHC) was predicting Nicholas’s top sustained winds will reach 65 mph prior to an expected landfall. If Nicholas’s track ends up displaced a bit to the east, it could approach hurricane strength before reaching Texas on Tuesday, as suggested by the 12Z Sunday run of the HWRF model. Conversely, a more westward track displacement could bring Nicholas just inland over South Texas on Monday as a weak tropical storm.

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Source: Yale Climate Connections