Update, 5:40 p.m. Friday
An evening update about the ongoing weather outlook, though nothing much has changed much about the forecast over course of the afternoon.
Galveston County is still under a flash flood watch and will be until 7 p.m. on Saturday according to the National Weather Service.
Showers and thunderstorms will develop again tonight and into Saturday morning. Heavy rainfall will be possible and could result in flash flooding.
There could be as much as another 5 inches of rain over the next day, according to the weather service.
Update, 10:14 a.m. Friday
A flash flood watch is still in effect in Galveston County until 7 p.m. Saturday.
Showers and thunderstorms will develop again on Friday evening and continue into Saturday morning, according to the National Weather Service.
Heavy rainfall could result in flash flooding, rising water levels in local bayous.
Update, 8:12 a.m. Friday
Offices and courts at the Galveston County Justice Center, 600 59th St. in Galveston, will not open until 10 a.m., county officials said.
Update, 7:15 a.m. Friday
Up to 6 inches of rain fell on parts of Galveston County overnight, causing flooding in some areas, according to the National Weather Service.
Rain is expected to continue on Friday, but is not expected to bring more flooding. The rain may prevent flood waters from receding quickly, however, according to the weather service.
Another round of thunderstorms and heavy rainfall is expected Friday night into Saturday morning.
Update, 6:50 a.m. Friday
College of the Mainland in Texas City and the University of Houston Clear Lake are closed.
Update, 6:41 a.m. Friday
Multiple Galveston County school districts have announced school closures for Friday, May 10.
Texas City Independent School District, Santa Fe Independent School District, Dickinson Independent School District, Hitchcock Independent School District, Friendswood Independent School District and Clear Creek Independent School are all closed today.
Update, 12:35 a.m. Friday
There is a flash flood warning in place for northwestern Galveston County, including northern Friendswood, until 4:30 a.m.
Rainfall in continuing across the county, but its intensity has diminished, according to the National Weather Service. Flooding and flash flooding is ongoing.
Update, 12:02 a.m. Friday
The severe thunderstorm warning in southeast Galveston County has been extended to 12:45 a.m.
Update, 11:53 p.m. Thursday
The tornado warning for Galveston Island has expired, but a severe thunderstorm warning is still in effect until midnight.
Large hail and damaging winds remain likely, according to the National Weather Service.
Update, 11:35 p.m. Thursday
Centerpoint Energy is reporting nearly 1,000 power outages in Santa Fe and hundred more in the San Leon area.
Texas-New Mexico Power is reporting nearly 1,300 power outages in League City.
Update, 11:22 p.m. Thursday
Eastern parts of Galveston Island are under a tornado warning until 11:45 p.m., according to the National Weather Service.
A severe thunderstorm capable of producing a tornado was moving southeast from La Marque at 11:22 p.m.
The storm will be near Bayou Vista at 11:25 p.m. and reach the Galveston Causeway by 11:40 p.m., according to the weather service.
The weather service is urging people to take cover now and to avoid windows. Do not go outside.
Update, 11:18 p.m. Thursday
A severe thunderstorm warning is in effect in Galveston County until midnight, according to the National Weather Service.
A line of storms capable of producing ping pong-ball sized hail was moving east from Smith Point at 11:10 p.m.
The weather service advises moving to interior rooms on lower floors for protection.
The warning includes League City, Galveston, Texas City, Dickinson, La Marque, Santa Fe, Hitchcock and Kemah.
Update, 11:15 p.m. Thursday
Houston Transtar is warning of a high risk of flooded roadways in the northern parts of Galveston County, north of FM 646.
Update, 11:10 p.m. Thursday
A flash flood warning has been issued for Galveston County until 2:15 a.m.
The warning includes all of Galveston County.
Update, 11:05 p.m. Thursday
Coastal Galveston County is under a tornado warning until 11:45 p.m.
A severe thunderstorm capable of producing a tornado was detected 7 miles north of Smith Point at 11:01 p.m., moving east at 20 mph, according to the National Weather Service.
A tornado is capable of causing flying debris, and of damaging or destroying mobile homes. Damage to roofs, windows and vehicles will occur and tree damage is likely, according to the weather service.
The storm will be near Gilchrist and Rollover Pass on Bolivar Peninsula around 11:45 p.m.
Update, 11:00 p.m. Thursday
The Harris County Flood Warning System reports more than an inch of rain fell at Cowart Creek near Baker Road near Friendswood between 10:45 p.m. and 11 p.m. Street flooding is possible in the area.
Update, 10:45 p.m. Thursday
Almost all of Galveston County is under a severe thunderstorm warning until 11:30 p.m., according to the National Weather Service.
A line of thunderstorms was detected near Baytown at 10:41 p.m. and was moving east at 35 mph.
The storm featured wind gusts up to 60 mph and quarter-sized hail.
The warning includes League City, Texas City, Friendswood, Dickinson, La Marque, Santa Fe and Hitchcock.
Update, 10:40 p.m. Thursday
The National Weather Service has issued a flood advisory for all of Galveston County until 1:30 a.m.
Heavy rain and thunderstorm will cause minor flooding across the county, according to the weather service.
Update, 9:49 p.m. Thursday
Santa Fe ISD will notify staff and students about possible closures by 6 a.m. on Friday, the district said in a Twitter post.
Clear Creek ISD will also make a decision at 6 a.m., the district said.
Update, 9:37 p.m. Thursday
Northwestern Galveston County is now under a flash flood warning, meaning that a flash flood in imminent or occurring.
A thunderstorm was dropping heavy rain on an area that includes northern Friendswood and Webster, according to the National Weather Service.
In a Facebook post, Friendswood ISD said it would assess road conditions at 4 a.m. Friday to decide if schools would be delayed or canceled.
Update, 9:20 p.m. Thursday
The National Weather Service has issued a flood advisory for northwestern Galveston County until 11:15 p.m.
Heavy rain will cause minor flooding in areas including League City, Friendswood, Alvin and Webster, according to the weather service.
Update, 8:40 p.m. Thursday
Galveston County is under a severe thunderstorm watch until 1 a.m. Friday, according to the National Weather Service in League City.
The county is also still under a flash flood watch.
There have been no reports of major flooding or rain in Galveston County as of right now. The City of Galveston has warned that thunderstorms will begin around 10 p.m.
Original story, 10:30 a.m. Thursday
The National Weather Service in League City has announced that a flash flood watch will be in effect in Galveston County beginning at 1 p.m. Thursday.
The watch is expected to remain in effect through Saturday evening.
Multiple rounds of heavy rain are anticipated over the next three days, the weather service said. The watch includes a wide swath of southeast Texas, from the Texas-Louisiana state line to Rockport and College Station and points between.
There could be up to 8 inches of rainfall in widespread areas and as much as 12 inches of rain in isolated areas, according to the weather service.
Galveston and other coastal counties are considers to be at moderate risk for heavy rains through Saturday, according to the weather service.
The weather service also warned of hazardous swimming conditions at area beaches. Persistent winds are causing minor beach flooding and strong rip currents on Galveston Island and Bolivar Peninsula, the weather service said.
Kevin M. Cox contributed to this report.