Published: October 31,2015
As much as 13 inches of rain in upper coastal Texas spawned major flash flooding across Houston, Texas, and nearby communities Saturday. Flash floods with torrential rain in central Texas have killed at least four people since Friday, and closed countless roads and flooded homes.
(MORE: Flash Flooding, Tornadoes Reported)
Latest Radar, Flooding, Severe Alerts
The National Weather Service issued flash flood warnings for parts of Louisiana and southern Mississippi Saturday.
Flood watches continue from parts of Louisiana into southern Alabama.(INTERACTIVE: Flood Alerts)
Gulf Moisture Feeds Heavy Rain ThreatAs jet stream energy slips through the southern Plains and toward the lower Mississippi Valley, a plume of moisture from the Gulf continues to surge north.
Low pressure advancing across the Gulf Coast states will be accompanied by the threat for heavy rain over much of the Southeast through Monday.
The storm system will not exit the East Coast until early next week, although the intensity of the rain will tend to become less extreme with time.
Still, widespread rainfall totals of 1 to 3 inches are expected from the central Gulf Coast to parts of the Carolinas and Virginia, with locally higher amounts.
The focus for any severe thunderstorms is mainly along and near the Gulf Coast through Sunday.
Heavy Rain Threat Setup This Weekend
(MORE: Severe T-Storm Forecast)
Timing of the RainA broad area of rain across the Deep South will progress east, eventually reaching the Carolinas and lower Middle Atlantic region by Monday. The focus for the heaviest rainfall will be where bands and clusters of thunderstorms develop, locally enhancing rainfall rates.
Sunday: Early in the day, heavy rainfall will persist across much of Louisiana and parts of Mississippi with some of that heavy rain likely moving through northwestern Georgia as well. Further south and east, thunderstorms over southern Alabama and the western Florida panhandle may also pose a threat of gusty winds and flash flooding.
Later in the day, a second round of thunderstorms will target southern Mississippi, southern Alabama, the Florida panhandle and perhaps southwestern Georgia. Here, a few isolated severe thunderstorms cannot be ruled out.
Rain should be tapering off over Alabama into the Tennessee Valley with the bulk of the precipitation exiting the East Coast late Monday night.
Additional Flooding and Rainfall ReportsThe final estimated daily rainfall total on Friday for Austin Bergstrom International Airport was 14.99 inches, according to the San Antonio National Weather Service office. The total had to be estimated because the Automated Surface Observing System (ASOS) equipment that normally records weather data at the airport malfunctioned after 5.76 inches of rain fell in a single hour, an amount exceed by only six prior 24-hour calendar days in the site's history.
This narrowly missed tying the wettest calendar day in the city's history, 15.00 inches on September 9, 1921. This one-day total was greater than the five-month average precipitation from August through December (14.23 inches).
At one point, an hourly rain rate of 7 inches was measured by the nearby Lower Colorado River Authority (LCRA) gauge along Onion Creek at U.S. 183, used to calculate a provisional total until the NWS can determine whether all the day's data can be salvaged from the airport's hobbled ASOS. That gauge recorded 13.40 inches of rain in just 3 hours Friday morning.
That's wetter than any previous 15-day period on record for the airport site since records began in 1942. Combined with rains from the Oct. 22-25 storm, ABIA picked up more than 22 inches of rainfall in just nine days.
Onion Creek subsequently climbed to a crest of 39.12 feet, which is more than 22 feet above flood stage and second only to its all-time crest of 40.2 feet set almost exactly two years ago. Records at the gauge date back at least 146 years.
Upstream, Onion Creek shattered its previous record crest at Driftwood of 25.1 feet during the devastating flash floods of Oct. 17, 1998.
In Houston, both Hobby and Intercontinental airports set daily rainfall records on Saturday with each site picking up more than 5 inches of rain for the day.
Selected Rainfall Totals
- Houston: Numerous reports of high water, rescues particularly in south metro Saturday morning. Over 13 inches of rain in parts of Harris County. Forty homes flooded in east side near I-10 and Beltway 8.
- Liberty, Texas: Six homes flooded, numerous roads closed
- Corsicana, Texas: Interstate 45 was shut down in both directions in Navarro County overnight Friday night, but was reopened Saturday morning.
- Lake Mexia, Texas: Lake levels rose to 4 feet above normal pool, prompting evacuations of some residents near the lake.
- Dallas-Ft. Worth metro: At least one water rescue in downtown Dallas; street closures in Rowlett.
- Bastrop, Texas: Evacuations along the Colorado River Saturday; homes flooded.
- Brownsville: Water entering a home near Brownsville-S. Padre International Airport; 4.71 inches of rain in roughly 1 hour and 45 minutes through 12:39 p.m. CDT.
- Comal County: Evacuations along Guadalupe and Comal Rivers
- San Marcos: The Blanco River rose 34 feet from Friday morning to the afternoon, cresting just under one-half a foot lower than its destructive Memorial Day flood crest.
- Wimberley: Flooding along Cypress Creek prompted evacuations the site of severe flooding in May. Rapidly-moving water was reported over the State Highway 12 bridge there. The Blanco River crested just over 13.5 feet above flood stage just before midday Friday, nearly matching the Halloween 2013 crest, but over 18 feet lower than the historic May flood event.