DC area forecast: Brief showers today. Saturday the choice of the weekend.
A wide swath of the deep South and southern plains will be most affected, where 2 to 4 inches of rain generally could bring localized flooding. Some of the heaviest could fall in the greater Houston metro area, where flood watches are in effect through Saturday.
The storm is not particularly severe, as strong winds and tornadoes will not be a concern, but it can be argued that it comes during the worst time of the year as people travel home after the Thanksgiving holiday. During this post-Buddhist travel peak, an estimated 55 million Americans will drive 50 miles or more. Millions more will take to the skies or the rails. Anytime travel is involved, weather is critical.
The storm is intensifying over the Texas Trans-Pecos and northern Chihuahua, Mexico, where a clockwise vortex can be seen on water vapor satellite imagery. Ahead of the system, relatively light, moister air is heading north, followed by cooler Canadian air crashing south.
Where the moisture and cold air overlap, snow is falling. That’s the case in southeastern New Mexico, the west Texas Hill Country and the Big Bend in Texas. Winter storm warnings are in effect for Marfa, Tex., and Carlsbad, NM, with a winter weather advisory for Lubbock. The Interstate 10 corridor could be heavily impacted.
Farther east, rain was falling on the warm side of the system between Abilene and the Dallas-Fort Worth Metroplex. Additional downpours and thunderstorms were falling offshore in Houston.
Drizzle & a few showers this AM. Rain cover increasing this evening, becoming widespread late night/evening.
— NWS Houston (@NWSHouston) November 25, 2022
As the system intensifies, it will pull a tongue of Gulf of Mexico moisture northward. That would result in a conveyor belt of water spills repeatedly targeting Houston. The National Weather Service’s Weather Prediction Center has issued a level 3 out of 4 moderate risk of heavy rain and flash flooding across the city.
The local National Weather Service office warns that rain rates of up to 2 inches per hour are expected with higher rates of up to 4 inches per hour in the stronger and slower storms. This can quickly lead to serious accumulations that exceed the ground’s ability to absorb runoff, especially in urban areas and more densely populated areas.
Further north and west, Austin, Dallas and Longview could see an inch or more, while Interstates 10, 20, 30 and 35 are likely to experience slight delays.
In the Houston to Galveston corridor, also a major hub for air travel, the heaviest rain will come down Friday afternoon into the first half of Saturday. Can be anywhere from 2 to 5 inches or more, with the largest totals coming from downpours that train, or move repeatedly over the same areas.
A marginal level 1 out of 5 severe weather risk also covers parts of the South Texas coast, including the Matagorda Peninsula, where a short-lived tornado cannot be ruled out.
Heavy rain across the South and Midwest
By Saturday morning, the strengthening low will move toward Central Texas, spreading the main axis of locally moderate rain to Oklahoma, Arkansas, Louisiana and East Texas. A six to 10 hour window of moderate rain will cross through Mississippi, Alabama and Tennessee during the second half of Saturday into Sunday night or early Sunday, with a region of lighter rain “wrapping” back west around the pressure center low.
A general 1 to 2 inches of rain is likely across most of the South, with half an inch to an inch in Tennessee. Parts of the Midwest may also see some decent rain, with a little more than an inch in most of central and southern Illinois, Indiana and Missouri. The amounts decrease east of the Appalachians.
Rain on Sunday along the East coast
The Interstate 95 corridor in the Carolinas and the Mid-Atlantic will get its rain, about half an inch to three-quarters of an inch, centered around noon Sunday, give or take a few hours. It won’t be a washout, but some moderate to heavy rain can be expected. Lighter rain may reach all the way back to Chicago in the first half of the day Sunday; by Sunday night into Monday, the system will have retreated to New England.
This could make for some slow travel between cities like Charlotte, Raleigh, Washington, DC and New York City. Boston, Providence and Hartford will be most affected after dark.