More severe weather threatens Southeast Texas Friday with some areas already experiencing 2 to 4 inches of rain. Although a tornado warning was briefly issued, there is still a small threat of small hail and gusty winds with these thunderstorms.

Follow along with the Houston Chronicle's live coverage of the storm.

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Flood warning

A flash flood warning was in effect for northwestern Montgomery County and south-central Walker County until 10:15 a.m. Friday, the National Weather Service said.

The warning originally was set to expire at 9:30 a.m. but at 9 a.m., the weather service extended it. Data from Doppler weather radar at 6:31 a.m. and rain gauges had initially indicated that thunderstorms across Montgomery and Walker counties had produced 2 to 4 inches of rain already. Flash flooding was occurring, and forecasters said an additional inch to 2 inches of rainfall were possible.

“Rainfall from the previous day resulted in high water along FM 1097, with portions of the roadway along the northeast side of Montgomery washing out,” the weather service said in its announcement of the warning. “High water was also reported at FM 149 at Little Lake Creek and Lawson Street at Liberty Street.”

FLOOD TRACKER: Get real-time flood updates for Houston and view live weather radar

Avoid driving through flash flooding along small creeks and streams, urban areas with poor drainage, flooded roadways, underpasses and low-lying area, forecasters said.

Separately, a flood advisory was in effect until 10:15 a.m. Friday for Harris County because of excessive rainfall, the weather service said. While a flood warning is an alert for ongoing or imminent flooding, a flood advisory is similar but for less serious levels of flooding.

Doppler weather radar and rain gauges at 7:12 a.m. indicated heavy rainfall amounts of an inch to 2 inches. Up to another inch of rain was expected in the advisory area, which could lead to minor flooding, forecasters said.

Places that could experience flooding include northwestern Pasadena, northern Missouri City, South Houston, Bellaire, Humble, West University Place, Galena Park, Jacinto City, Jersey Village, Hunters Creek Village, Bunker Hill Village, Piney Point Village, Greater Heights, Memorial Park, Afton Oaks/River Oaks area, Neartown/Montrose, near Northside Houston, Fourth Ward, Northside/Northline and Greenway/Upper Kirby area.

Brief tornado warning

A tornado warning was briefly issued at 6:53 a.m. for south-central Wharton, east-central Jackson and northwestern Matagorda counties before it was canceled about 15 minutes later.

“The storm which prompted the warning has weakened below severe limits, and no longer appears capable of producing a tornado,” the weather service said, adding that, “however, small hail and gusty winds are still possible with this thunderstorm.”

Severe thunderstorm watch

Meanwhile, a severe thunderstorm watch remained in effect for much of Southeast Texas until 11 a.m. Friday, the National Weather Service said. The latest round of potentially damaging storms comes on the last day of a month that has already seen devastating floods and tornadoes rip through the region.

Strong thunderstorms at 6 a.m. Friday were already affecting or approaching Colorado, Austin, Grimes, Burleson, Brazos, Washington, Montgomery, Waller and Harris counties. But some counties were gradually dropped from the watch area as the line of storms moved through.

By 7:40 a.m., the weather service dropped 12 counties from the thunderstorm watch area: Austin, Brazos, Burleson, Colorado, Grimes, Houston, Madison, Montgomery, Trinity, Walker, Waller and Washington.

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Damaging wind gusts and large hail were the primary threats with these storms, weather service meteorologist Jimmy Fowler said.

Communities affected included College Station, Bryan, western Conroe, Huntsville, Brenham, Navasota, Crockett, Hempstead, Willis, Prairie View, Madisonville, Caldwell, Bellville, Pinehurst, Austonio, The Woodlands, Washington, Waller, Panorama Village, and Grapeland.

The weather service had reported that at 5:35 a.m. severe thunderstorms had formed along a line extending from 8 miles southwest of Elkhart to near Navasota, moving east at 40 mph. Doppler weather radar indicated 60 mph wind gusts and penny-size hail, both of which were capable of damaging roofs, home siding and trees, forecasters said.

By 5:57 a.m., the line of severe thunderstorms extended from 7 miles west of Riverside in Walker County to 6 miles north of Columbus in Colorado County, moving southeast at around 40 mph. About 15 minutes later, the line of storms stretched from 7 miles northeast of Huntsville to 7 miles southeast of Columbus, still moving southeast at 40 mph.

At 7:17 a.m. a severe thunderstorm was located near Blessing, or 13 miles north of Palacios, moving southeast at 20 mph, while another storm at 7:25 a.m. was over eastern Pearland, also moving southeast at 20 mph, as well as producing 60 mph wind gusts and quarter-size hail.