The fourth-largest city in the nation can’t catch a break weather-wise. After multiple violent thunderstorms in May and Hurricane Beryl earlier this month, Houston now faces half a foot of rain and the potential for areas of flooding this week.
Rainfall amounts will vary significantly around the city, so not everyone will experience flooding. But a moisture-loaded tropical air mass will produce torrential downpours that will pass repeatedly over some of the same areas.
Rainfall rates could reach up to 2 to 4 inches per hour in the heaviest storms, according to the National Weather Service. Downpours are forecast to be most numerous through early Thursday before easing and becoming more sporadic.
SpaceCityWeather, a Houston weather blog, placed the city under its “Stage 1 flood alert,” meaning the city should expect mainly “minor impacts” and “nuisance street flooding.” Its scale for flooding goes up to Stage 5 — so this is not expected to rival some of the more extreme events in recent history such as Hurricane Harvey in 2017. But it’s the latest in a siege of unwelcome weather events, which have left behind flooding, widespread downed trees and wires, and hundreds of thousands of customers without power.
A waterlogged week ahead
A widespread 4 to 6 inches of rain is expected along the Texas coast from Brownsville to the border with Louisiana, with localized greater totals. It won’t all fall at once — with off-and-on rains through Thursday night. Amounts will decrease quickly inland, but much of the Interstate 10 corridor from Houston eastward should see soaking rain.
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Some weather models suggest the greatest moisture may stay just offshore; others depict the risk of up to 10-inch totals at the shoreline.
A stagnant area of low pressure at high altitudes has been present for days over the central United States, helping to produce downpours along its periphery.
Around Houston, atmospheric moisture levels are projected to be exceptional, and replenished continually by humid air streaming off the Gulf of Mexico.
A stalled front will also help focus showers and storms on Wednesday and Thursday. Some of these may be slow-moving, too. If they linger over the same areas, a quick 3 or 4 inches of rain could fall in just a couple of hours.
Saturated ground from previous downpours will increase the risk of flooding. More than 15 inches of rain has fallen in Houston since June 1, nearly double the norm. Beryl unloaded 6 to 12 inches on its own.
Houston: An extreme weather magnet
It’s been barely two weeks since Beryl slammed Houston as a Category 1 hurricane with widespread 80 to 90 mph gusts. Long-lasting power outages and heat in the storm’s wake contributed to multiple deaths.
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And only two months have passed since a derecho, or violent, fast-moving windstorm, barreled through Houston, bringing 90 to 100 mph gusts and spawning an EF1 tornado near Cypress. Then more severe storms came on May 28, knocking out power to 1.4 million in Texas.
This year has been far from an anomaly.
Houston is among the most extreme weather-prone cities in the nation. At least 10 tornadoes have hit Harris County in the past five years, including an EF3 on the 0-to-5 scale for intensity on Jan. 24, 2023; it traveled 23.3 miles from Pearland to Baytown near Interstate 10. A deadly winter storm iced over the city in mid-February 2021, with temperatures plummeting to 13 degrees. Last summer, Houston had 45 days with temperatures at or above 100 degrees. Fifteen hurricanes have directly impacted Houston in the past century, as well as countless tropical storms.
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And Houston has been ground zero for some of the most significant flooding ever to strike North America. Houston was left mostly underwater after the remnants of Harvey stalled over the area in 2017; a U.S. record 60.58 inches of rain fell in Nederland, Tex. Harvey was Houston’s third 500-year (or greater) flood in three years.
As the climate continues to warm, the atmosphere’s moisture-holding capacity will markedly increase. (For every degree the air temperature warms, the air can hold 4 percent more water.) For places with readily available moisture such as Houston, just 40 miles inland from the Gulf of Mexico, that translates to heavier downpours.
The warming climate is also fueling an increase in ocean temperatures, which can foster a last-minute strengthening before a tropical storm or hurricane comes ashore. That was an issue with Beryl, which intensified right before landfall. Peer-reviewed articles suggest a link between rising ocean temperatures and stronger storms more prone to rapidly intensify before landfall.
Jason Samenow contributed to this report.
