It doesn’t take a hurricane or tropical storm to dump massive amounts of rain on southeast Texas these days. Just a wave of tropical moisture from an ocean warmed by human-caused climate change.

(Not a hurricane, but southeast Texas may see 20 inches or more of rain this week.)

Over the past few days, a massive surge of moisture has flowed off the warmer than normal waters of the Gulf of Mexico. This moisture has interacted with a trough dipping down over the Central U.S. to produce prodigious amounts of rainfall. And ever since late Sunday powerful thunderstorms have been firing across the Texas coast.

As of this morning, according to reports from The National Weather Service, between 5 and 15 inches of rainfall had inundated a vast swath stretching from the Texas-Mexico border northward to a Houston area still recovering from Hurricane Harvey’s historic floods. These heavy rains, producing amounts typically seen from a substantial tropical cyclone, have generated major flooding and flash flood warnings across the region. As the waters rise, residents have become justifiably concerned about personal safety and damage to property.

NOAA forecasts indicate that storms expected to continue firing through Thursday, with between 2 and 7 inches of additional rainfall possible. It is worth noting that atmospheric moisture levels over the region are very high. So predicted rainfall totals may be exceeded.

(As of 7 AM, more than 15 inches of rain had fallen over parts of southeast Texas in association with a persistent upper level low and related severe thunderstorms. Heavy rains have continued to fall throughout the day and aren’t expected to abate until at least Thursday. Image source: The National Weather Service.)

During recent years, increased global temperatures have generated more extreme rainfall events for places like southeastern Texas. Warmer ocean surfaces — like those in the heating Gulf of Mexico — evaporate more moisture into the atmosphere. And this moisture generates more fuel for storms — greatly increasing the peak rainfall potential of the most intense storms.

Last year, southeast Texas faced inundation from a number of severe events. A sequence that was capped off by the record-shattering Hurricane Harvey — which tied Katrina as the costliest U.S. storm on record and dumped more than 60 inches of rainfall over parts of the state. Though the present storm event is not likely to reach Harvey levels of extremity, it is a stark reminder that we have entered a new climate and extreme weather regime. One that will continue to worsen so long as we keep burning fossil fuels and forcing global temperatures to rise.