Texas rain moves inland, eyes Southwest
After the slow-moving tropical rainstorm dropped over 8 inches of rain in some areas, heavy rainfall is set to move westward in the coming days.
Heavy rainfall brought on by a tropical rainstorm that flirted with becoming a named system over the weekend continued drenching parts of Texas on Monday as it gradually lurched inland, causing flash flooding and scenes that certainly looked reminiscent of a named tropical system.
AccuWeather forecasters warn that heavy rain will continue in southern Texas as precipitation moves to the north and west, soaking both sides of the U.S.-Mexico border. Later this week, the system is poised to bring rain as far inland as Albuquerque, Phoenix and even Las Vegas.
Radar estimates indicated that 5 to 10 inches of rain fell in the worst-hit areas over a three-day period. Hebbronville Airport, southwest of Corpus Christi, measured 7.33 inches, while a measurement of 6.21 inches was recorded at Corpus Christi Airport. An amateur weather observer at Flour Bluff, near Corpus Christi, saw 9.13 inches fall during that period.
The heaviest rain had ended along the South Texas coast as of the midday hours on Monday but was ramping up farther inland over the Rio Grande Valley.
AccuWeather meteorologists began monitoring a budding tropical rainstorm during the middle of last week. Even though it never had the chance to become an organized tropical system such as a depression or tropical storm, it still has unloaded heavy tropical rainfall and even showed some signs of circulation in satellite imagery.
On Saturday, pockets of convection existed across the northwest Gulf of Mexico and Texas coast, although the storm's appearance was rather disorganized. On Sunday morning, more persistent rounds of rainfall began to push into the southern Texas coast.
A wide swath of heavy rain is likely to continue in the path of the storm, totaling as much as 4-8 inches (100-200 mm) from southern Texas into northern Mexico.
Heavy rainfall is expected to be the main impact from the tropical system, threatening flooding along its westward path. This will be especially true in the higher terrain in northern Mexico, which is likely to trap a lot of the tropical moisture where an AccuWeather Local StormMax™ of 20 inches (500 mm) of rain is possible. In this area, downpours could be heavy enough to wash away roads and to cause mudslides.
Due to the isolated threat of flooding, this tropical rainstorm is rated as less than one on the AccuWeather RealImpact™ Scale for Hurricanes.
AccuWeather meteorologists warn that the rainstorm will still have the potential to bring a few stronger wind gusts and even an isolated tornado. On Sunday afternoon, a tornado warning was issued in a portion of southeastern Texas that included the city of Katy.
While the rainfall could be heavy enough across portions of Mexico and southern Texas to lead to flooding, the rainfall, in the long run, could be beneficial.
An astounding 88% of the state of Texas is in severe drought, and more than two-thirds of the state is in extreme drought, according to the most recent U.S. Drought Monitor report released on Thursday.
Since June 1, rainfall over South Texas ranges from 10-20% of normal near the coast to barely a few percentage points farther Inland prior to the tropical rainstorm. Laredo, Texas, has received only 0.61 of an inch of rain since the start of June, compared to a normal amount near 4 inches, and all of that fell in August.
"The tropical rainstorm is expected to eventually become a non-trackable feature," said AccuWeather Senior Meteorologist Adam Douty. But, the system is likely to maintain some composure into at least Wednesday.
A lot of the moisture from the tropical rainstorm is expected to be lost in the mountains of northern Mexico as the storm dissipates; however, just enough could sneak into the southwestern U.S. by way of the North American monsoon.
The annual weather pattern has brought rounds of downpours into portions of New Mexico, Arizona, Nevada, Utah and Colorado for weeks, helping to alleviate the drought conditions in the region as well as causing episodes of flooding.
A bit of lingering moisture from the tropical rainstorm could get picked up by the monsoon pattern midweek, helping to enhance the rainfall across the southwestern U.S., particularly along the Arizona-New Mexico border.
The extra surge of moisture could lead to heavier downpours with thunderstorms that develop in this area during the afternoons. These rounds of heavier rainfall could continue to impact parts of the Southeast even into next weekend.
The same area has been hit with so much rain in the last month, that there will be a risk for flash flooding, and even mudslides in the higher elevations.
Albuquerque, New Mexico, has already recorded 84% of its normal rainfall for the entire month of August through Aug. 15. The half inch of rain that Yuma, Arizona, recorded so far in August is 260% of normal.
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