The National Weather Service is predicting heavy rain early Monday, prompting a flash flood watch for the entire Houston metro area.

Showers and thunderstorms were expected to start about midnight and spread across the region, however the system appeared to slow overnight. As of 6 a.m. Monday, the first round of storms – which battered the San Antonio region overnight – were expected to hit Houston by about 7 a.m.

A few storms could become strong with gusty winds and small hail that could topple trees and power lines.

City of Houston officials activated the emergency operations center overnight and are ready for water rescues and to barricade high-water sites.

Houston ISD officials released a statement Sunday night saying they will "notify parents, students and staff of any precautionary actions early Monday morning." Some other districts were off Monday, or were teach in-service days only, due to the President's Day holiday.

CAUTION: With heavy rains expected, remember these places flood the most

Overnight forecasts did not indicate rainfalls heavy enough to overflow Buffalo Bayou or other waterways, said Francisco Sanchez, spokesperson for the Harris County Security and Emergency Management Office. But ground saturated from rains last week could cause flooding elsewhere. "It could happen anywhere in the Southeast Texas area," he said.

A flash flood watch has been issued from 3 a.m. until 4 p.m. Monday for Austin, Brazoria, Chambers, Colorado, Fort Bend, Galveston, Grimes, Harris, Jackson, Liberty, Matagorda, Montgomery, San Jacinto, Walker, Waller, Washington and Wharton counties.

Rescue crews will be available if needed for those in Houston, said Michael Walter, a spokesman for the city's Office of Emergency Management.

You can check for the latest forecast at weather.chron.com.

>>>Scroll through the above gallery to see the places around Houston that have the highest rates of flooding.