Hurricane watch in effect for Texas as Nicholas strengthens in Gulf

Officials in Texas and Louisiana are sounding the alarm ahead of the latest tropical threat to take aim at the Gulf Coast region. Tropical Storm Nicholas was closing in on the coast of Texas Monday morning, and AccuWeather forecasters said the storm could produce a significant flooding threat around the greater Houston area.

As of 8 a.m. EDT Monday, Nicholas was moving erratically about 210 miles south of Port O'Connor, Texas, and 40 miles southeast of the mouth of the Rio Grande River. The storm had maximum sustained winds of 60 mph and was slowly moving to the north at a speed of 5 mph, down from 14 mph three hours earlier. Tropical-storm-force winds extended outward up to 115 miles from the center of Nicholas.

A hurricane watch covered areas from Port Aransas to Freeport, Texas, while a tropical storm warning was in effect for the coast of Texas from the mouth of the Rio Grande to High Island, Texas, the National Hurricane Center (NHC) said. A tropical storm watch was issued for areas from the mouth of the Rio Grande to Port Aransas, Texas, and storm surge warnings were in place for parts of the Texas coast.

A state of emergency was declared in Louisiana by Gov. John Bel Edwards Sunday while Texas Gov. Greg Abbott raised the state's emergency alert level and readied incident management teams which included swift water rescue boat squads.

"The State of Texas has deployed resources ahead of this tropical system, which is expected to impact the Gulf Coast beginning on Sunday," said Abbott. "We will continue to closely monitor this storm and take all necessary precautions to keep Texans safe. I encourage Texans to follow the guidance and warnings of their local officials and be mindful of potential heavy rain and flooding."

Nicholas, the 14th named storm of the 2021 Atlantic hurricane season, was expected to bring heavy rain to areas of southwestern Louisiana still recovering from hurricanes Laura and Delta in 2020. Parts of the state that were struck by Hurricane Ida last month could also be impacted, Edwards said. "The most severe threat to Louisiana is in the southwest portion of the state, where recovery from Hurricane Laura and the May flooding is ongoing. In this area heavy rain and flash flooding are possible," Edwards said.

"However, it is also likely that all of south Louisiana will see heavy rain this week, including areas recently affected by Hurricane Ida. This tropical storm has the potential to disrupt some power restoration and recovery work currently underway. I encourage anyone who has had recent damage from Ida, Laura or other disasters to take necessary measures to protect their home or business from additional harm," Edwards said.

Wind shear remains an inhibiting factor for Nicholas to strengthen into a hurricane, but AccuWeather forecasters say there remains a chance that #Nicholas could develop into a Category 1 hurricane.

Wind shear is the change in direction and speed of winds at increasing heights in the atmosphere. When strong wind shear is present, the top of a tropical system can be blown hundreds of miles downstream and the system could become very lopsided or tilted.

Nicholas will continue to ride northward and bring a flood and wind threat to coastal Mexico through early Monday.

"The shear is expected to lessen a bit on Monday, which may allow the system to continue to strengthen from a weak tropical storm into a strong tropical storm," said AccuWeather Senior Meteorologist Rob Miller.

This satellite image, captured Sunday morning, Sept. 12, 2021, shows a broad swirl of clouds associated with Tropical Storm Nicholas in the Gulf of Mexico. (CIRA/RAMMB)

"Because of the limited amount of time the system is likely to spend over warm Gulf of Mexico waters, it is unlikely for Tropical Storm Nicholas to become too strong, and thus it is not expected to reach hurricane strength," said AccuWeather Meteorologist Ryan Adamson.

Nicholas is forecast to make landfall on the Texas coast between Corpus Christi and Galveston, Texas, Monday as a tropical storm. It can bring impacts to the Gulf Coast long before landfall, though. Due to the system's slow, curved path, heavy rain will be the biggest threat, though high winds are possible as well, making the storm a 1 on the AccuWeather RealImpact™ Scale for the U.S.

Stormy weather occurred across most of the region on Sunday, including in Houston as well as New Orleans, Lafayette and Lake Charles, Louisiana.

Rain from Nicholas will mark the start of an extremely wet event. While New Orleans, which was greatly impacted by Ida, can expect only 1 to 2 inches of rain total, Houston is set to receive 8 to 12 inches, with an AccuWeather Local StormMax™ of 24 inches nearby.

"Areas from Galveston to Port Arthur, Texas, are forecast to get the heaviest rain," said Miller.

Though most of the areas hard hit by Ida will have more minor impacts, some of the same locations impacted by hurricanes Laura and Delta last year will want to keep a sharp eye on the forecast.

"Both Laura and Delta made landfall in southwestern Louisiana only 13 miles apart and within 43 days of each other," said Adamson. Laura struck as a Category 4 hurricane on Aug. 27, while Delta arrived as a Category 2 hurricane on Oct. 9.

Flooding could also occur where rain has been plentiful lately, including Victoria, Texas, and Lake Charles.

"Both Victoria and Lake Charles picked up more than 20 inches of rain this past May, which was four times that of average," Adamson explained. Despite less extreme rain since then, rainfall has remained above average throughout the summer and flooding could be much easier in these spots.

Hurricane Harvey is another historic storm that greatly impacted the area of Houston years ago. Harvey made landfall on Aug. 25, 2017, and dropped as much as 61 inches of rain as it stalled, leaving catastrophic flooding in its wake. While a Harvey level of rainfall is not expected from this system, the impacts could be reminiscent of this due to the slow speed of the system. Double-digit rain amounts are expected, leading to significant flooding, especially on roads prone to taking on water during torrential downpours.

Residents and travelers within 75 miles of the Texas coast and southwestern Louisiana are urged to prepare for travel delays this week.

"Along with the likelihood of heavy rain and localized flooding will be rough surf and seas over the western part of the Gulf of Mexico through the middle part of this week from Nicholas," Adamson said. Rip currents are anticipated to increase over the next couple of days.

Though Nicholas is not expected to be extremely windy, like Laura or Delta, it can bring gusts from 40 to 60 mph to cities like Corpus Cristi and Victoria, with an AccuWeather Local StormMax™ of 70 mph. With a saturated ground from previous downpours, this wind can topple trees and power lines much more easily. Residents should be prepared for power outages.

CLICK HERE FOR THE FREE ACCUWEATHER APP

"Given the nature of the wind shear, most of the stronger winds associated with Nicholas will remain off the coast, but the highest gusts are expected at the coast, especially near landfall," said Miller.

With Nicholas developing in the Gulf, the 2021 Atlantic hurricane season is shaping up to be above average, though it may not feel that way after 2020 recorded 30 named systems.

"Typically, only 14 named storms form during the course of an entire season," said Adamson.

After such a historic season last year, the World Meteorological Organization created a list of secondary names in case future seasons, including 2021, need them.

For the latest weather news check back on AccuWeather.com. Watch AccuWeather Network on DIRECTV, DIRECTVstream, Frontier, Spectrum, fuboTV, Philo, and Verizon Fios. AccuWeatherNOW is streaming on Roku and XUMO.