- Heavy rainfall possible east of I-35 Friday through the weekend, possibly leading to flash flooding and river flooding.
- Average rainfall amounts of 6-10″ possible east of I-35 with isolated higher amounts in excess of 12″ in the Tropical Storm Watch area. This could lead to flash flooding and river flooding in this area. Areas along and west of I-35 could see 2-4 inches.
- There remains uncertainty in the forecast track of Harvey across Texas. Only small changes to the track or forward speed of Harvey will result in large changes to impacts across South Central Texas. Much higher rainfall amounts will be possible across South Central Texas, including areas into the I-35 corridor, if the track shifts further west or if Harvey stalls or slows forward speed.
Update Since Last Briefing:
- Forecast forward speed of Harvey over South Texas has slowed.
- Projected rainfall amounts east of I-35 have increased (see below).
- A Tropical Storm Watch remains in effect for Fayette, Gonzales, Wilson, Karnes, DeWitt, and Lavaca Counties.
Threats & Impacts:
Note…a change in track and intensity may dramatically change the impacts and locations of these threats/impacts.
Rainfall: 6-10 inches of rain east of Interstate 35 with isolated totals that may exceed 12 inches Friday through the weekend. These isolated totals are most likely to occur across Fayette, Lavaca, Gonzales, and DeWitt counties. Areas along and west of I-35 could see 2-4 inches. Flash Flooding and River Flooding is possible mainly across the Tropical Storm Watch area.
Winds: Tropical storm force winds of 40 to 50 mph are possible across the Tropical Storm Watch area beginning on Friday night. Gusts could exceed 60 mph. Areas to the west along the I-35 corridor may experience some low end tropical storm force wind gusts if bands push farther west.
Tornadoes: There may be a slight risk of tornadoes mainly along rain bands in the front right quadrant of landfall. These small tornadoes can happen day or night.
Timing and Overview:
Tropical Depression Harvey was located over the southwest Gulf of Mexico late this afternoon and continues to gradually organize. Over the next couple of days Harvey is expected to move northwest and strengthen into a strong Tropical Storm, making landfall along the middle Texas coast late Friday. On the current forecast track, tropical storm force winds are expected to affect southeast sections of South Central Texas on Friday and Saturday and have thus issued Tropical Storm Watches for this area (see County list above).
Flooding rain is expected to be the main concern with Harvey. There remains uncertainty in the forecast track of Harvey across Texas. Only small changes to the track or forward speed of Harvey will result in large changes to realized impacts across South Central Texas. Much higher rainfall amounts and significant flooding could be possible across South Central Texas, including areas into the I-35 corridor, if the track shifts further west or if Harvey stalls or slows forward speed.
As such please know that later updates may change the impact areas and threats.
At this time we urge you to remain closely aware of the changes to the forecast over the next 24-48 hours by monitoring the National Hurricane Center (www.hurricanes.gov) and your local forecast (www.weather.gov/sanantonio). As this system We expect greater detail and confidence in the forecast tomorrow.
Moderate for location and impacts of Harvey.
Additional Information Resources:
- NWS Austin / San Antonio Webpage: http://www.weather.gov/sanantonio
- National Hurricane Center: http://www.nhc.noaa.gov/
- Storm Prediction Center: http://www.spc.noaa.gov/
- Online Severe Weather Reporting: http://www.srh.noaa.gov/StormReport/SubmitReport.php?site=EWX
NWS Austin / San Antonio
Weather Forecast Office