Key Messaging Points:
- A life-threatening and catastrophic heavy rainfall event is expected east of I-35 and I-37.
- Average rainfall amounts of 10-20 inches are expected east of I-35 and I-37 Today through Tuesday. Isolated higher totals in excess of 25 inches are possible near and south of the I-10 corridor.
- Along the I-35 corridor and across the eastern Hill Country, including the City of San Antonio and Austin, 6-12 inches with isolated higher totals are possible.
- A tight rainfall gradient is expected on the western and northern edge of Harvey’s precipitation shield, near or along the I-35 corridor. Small shifts in the forecast track of Harvey, and where it stalls this weekend, could result in very large differences in rainfall totals.
- Catastrophic mainstem river flooding lasting many days is possible east of I-35 and I-37 in the Colorado, Guadalupe, and San Antonio river basins.
- Tropical Storm Force winds could arrive as early as this afternoon in rain bands.
- 70-80 mph winds are expected for counties in the Hurricane Warning. Large trees could be snapped, power lines downed, and damage to homes could occur. Power and communication outages are likely.
- 40-50 mph winds are expected within the area now under a Tropical Storm Warning with gusts to 60 mph in rain bands. This includes San Antonio to San Marcos areas. Damage to trees and power lines are possible, leading to scattered power outages.
- For Austin 20-30 mph with gusts in excess of 40 mph in rain bands.
- There is a marginal risk for tornadoes east of a I-35 and I-37 this afternoon through Saturday. These small tornadoes are typically very fast moving and short-lived.
Please reference attached pdf for supplemental graphics.
Update Since Last Briefing:
- The Tropical Storm Warning has been expanded into Comal and Hays counties.
- Rainfall amounts along I-35 corridor (includes San Antonio and Austin) adjusted to 6-12 inches with isolated higher amounts.