Areas of localized heavy rainfall leading to flash and river flooding will be possible Monday afternoon through early Thursday morning with the highest likelihood near the Rio Grande Plains and into the southern Edwards Plateau along U.S. Highway 83.
The greatest concentration of heavy rainfall and most likely window of flooding impacts appears to be Tuesday afternoon into Wednesday morning.
Area of Concern:
Rio Grande Plains into the Southern Edwards Plateau and portions of western Hill County regions. See Graphic below for more details.
Val Verde County could have moderate to heavy rain starting as early as Monday morning.
Threats & Impacts:
Rainfall: 3 to 6 inches with locally higher amounts to 8 inches in the area of concern. There is a possibility for even higher and very isolated amounts to 10 inches.
Flooding Impacts: Several locations may experience moderate flooding with flood waters capable of causing rivers and tributaries to become swollen and overspill their banks mainly in historically vulnerable places. Small streams, creeks, canals, and ditches overflow with some low lying structures flooded. Inundation occur at underpasses, low-lying spots, and poor drainage areas. Some streets and parking lots take on moving water. Storm drains and retention ponds overflow. Flood waters may prompt several evacuations and road closures
Timing and Overview:
The combination of a dissipating tropical storm from the Pacific will combine with a stalled front over the region early to mid-week. This set-up and an upper level-disturbance shifting over the region will support heavy rainfall over multiple time periods Monday through Thursday. The greatest concentration of rainfall appears to be Tuesday and Wednesday for the Rio Grande Plains and the Southern Edwards Plateau. Given the rocky soil in the expected highest rainfall total location, river and flash flooding is of particular concern.
Rainfall amounts: Moderate
Flooding Impacts: Moderate
Additional Information Resources:
- NWS Austin / San Antonio Contact Numbers: 800-292-5508 or 830-606-3617
- NWS Austin / San Antonio Webpage: http://www.weather.gov/sanantonio
- Online Flood Reporting: http://www.srh.noaa.gov/StormReport/SubmitReport.php?site=EWX
- Sign up to be Rainfall Observer: http://cocorahs.org/Application.aspx
- AHPS River Forecasts: http://water.weather.gov/ahps2/index.php?wfo=ewx