Updates Since Last Briefing: Increased Rainfall Amounts east of I-35 and east of I-37 Issued Flash Flood Watch.
Area of Concern:
Heavy rainfall potential across eastern Hill Country as well as along and east of the I-35 and I-37 corridors.
Threats & Impacts:
Rainfall: (see attached graphic for rainfall amounts)4-6 inches with locally higher amounts east of I-35 and east of I-37.3-5 inches across eastern Hill Country as well as along I-35 corridor (including Austin and San Antonio metros).1-3 inches across western Hill Country and Rio Grande. Flooding: (see attached graphic for Flash Flood Watch)Heavier rainfall could produce flooding of creeks, smaller tributaries, low water crossings, and urban areas normally subject to flooding.Mainstem of the Colorado River, lower Guadalupe River, and San Antonio River could be at play for minor to moderate flooding.Severe: (see attached graphic)Marginal risk for severe storms across far southeastern areas.If any strong to severe storms develop straight-line winds and small hail would be the impacts.
Timing and Overview:
A cold front and upper level disturbance will produce widespread showers and embedded thunderstorms Thursday night through early Saturday morning. The heaviest rainfall looks to fall Friday afternoon through Friday night.
While we have been relatively dry over the past few weeks, above normal rainfall earlier in the fall and dormant winter vegetation are contributing to above normal soil moisture values for early December. Quick runoff could begin developing Friday afternoon through Friday night, especially where pockets of heavier rainfall set up. This could eventually produce flooding of creeks, smaller tributaries, low water crossings, and urban areas normally subject to flooding. A Flash Flood Watch has been issued. With many events going on Friday and Saturday it is important to remain weather aware.
In addition, the West Gulf River Forecast Center also indicates the mainstem of the Colorado River, lower Guadalupe River, and San Antonio River could be at play for minor to moderate flooding.
Our confidence continues to decrease for severe thunderstorms. If any strong to severe storms develop straight-line winds and small hail would be the impacts across far southeastern counties Friday afternoon and evening. The Storm Prediction Center continues to place this area in a only a Marginal risk for severe storms.
Additional refinements to the rainfall forecast are likely over the next 24 hours. Our next update will be no later than Friday morning.
Rain Chances: Very HighRainfall Amounts: Moderate to HighArea of Heaviest Rainfall: Moderate to HighSevere Storms: Low