DC area forecast: Brief showers today. Saturday is the choice of the weekend.
Hardest affected will be a broad swath of the Deep South and southern Plains, where a general 2 to 4 inches of rain could cause localized flooding. Some of the heaviest could fall in the greater Houston metro area, where flood watches are in effect through Saturday.
The storm isn’t terribly intense, as strong winds and tornadoes won’t be an issue, but it’s likely coming during the worst possible time of year as people travel home for the Thanksgiving holiday. During this post-Thanksgiving travel peak, 55 million Americans are expected to drive 50 miles or more. Millions more will take to the skies or rails. Any time travel is involved, the weather becomes crucial.
The storm is intensifying over the Texas Trans-Pecos and northern Chihuahua, Mexico, where a pronounced counterclockwise swirl can be seen on water vapor satellite imagery. Ahead of the system, relatively mild, more humid air swirls north, with colder Canadian air plunging south in its wake.
Where the moisture and cold air overlap, plowable snow falls. This is the case in southeastern New Mexico, western parts of the Texas Hill Country, and the Big Bend of Texas. Winter storm warnings are in effect in Marfa, Tex., and Carlsbad, NM, with a winter weather advisory for Lubbock. The Interstate 10 corridor could be severely affected.
Further east, rain fell on the warm side of the system between Abilene and the Dallas-Fort Worth Metroplex. Additional showers and a few thunderstorms lurked along the coast of Houston.
Rain and a few showers this morning. Rain will increase in coverage this afternoon and become widespread by late afternoon/evening.
— NWS Houston (@NWSHouston) 25 November 2022
As the system intensifies, it will pull a tongue of Gulf of Mexico moisture northward. This would lead to a conveyor belt of torrential rain that repeatedly targets Houston. The National Weather Service Weather Prediction Center has drawn a level 3 out of 4 moderate risk of excessive rainfall and flash flooding around the city.
The local National Weather Service office warns that “rainfall rates up to 2 inches per hour are expected with higher rates up to 4 inches per hour in the stronger and slower moving storms.” This can quickly lead to serious accumulations that will overwhelm the soil’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, with some minor delays likely along Interstates 10, 20, 30 and 35.
In the Houston to Galveston corridor, also a major hub for air travel, the heaviest rain will fall Friday night into the first half of Saturday. Anywhere from 2 to 5 inches or more is possible, with the largest totals coming from showers that train, or repeatedly move over the same areas.
A level 1 out of 5 marginal risk of severe weather also covers parts of the South Texas coastline, including the Matagorda Peninsula, where a brief, fleeting tornado cannot be ruled out.
Heavy rain across the South and Midwest
By Saturday morning, the strengthening low will move into Central Texas, spreading the main axis of moderate to locally heavy rain into Oklahoma, Arkansas, Louisiana, and East Texas. A six- to 10-hour window of moderate rain will cross Mississippi, Alabama and Tennessee during the second half of Saturday into overnight or early Sunday, while a lighter region of “shrouded” rain wheels back west around the low pressure center.
A general rain of 1 to 2 inches is likely across most of the South, with half an inch to an inch in Tennessee. Parts of the Midwest could also see some decent rainfall, with a little over an inch in most of central and southern Illinois, Indiana and Missouri. Amounts decrease east of the Appalachians.
Sunday rain along the eastern coast
The Interstate 95 corridor in the Carolinas and Mid-Atlantic will see its rain, about a half-inch to three-quarters of an inch, arrive, centered around noon Sunday, give or take a few hours. It won’t be a washout, but some moderate to heavy showers can be expected. Lighter rain could reach all the way back to Chicago during the first half of the day Sunday; by Sunday evening into Monday, the system will have retreated to New England.
This can cause slow travel between cities like Charlotte, Raleigh, Washington, DC and New York City. Boston, Providence and Hartford will be most affected after dark.