Shown are the potential rainfall totals across Texas over the next seven days, according to the National Blend of Models.
WeatherBell
High atmospheric pressure — which had caused the warm, sunny and dry conditions across Texas last week — has weakened. In its place, a broad low-pressure system is developing across the western U.S., and very high levels of Gulf moisture are streaming into the state from the southeast.
This setup will result in widespread showers and thunderstorms across Texas this week, including cities like San Antonio, Austin, Dallas and Houston. High rainfall totals could result in flooding for some, especially by the second half of the week.
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Here’s a breakdown on how this week is expected to play out.
Sunday’s forecast
A very humid day is expected across South and Central Texas on Sunday. In San Antonio, morning low temps are expected to hover in the mid-70s, rising into the 80s by 10 a.m. Skies will stay mostly cloudy through the morning, but rain chances will stay very low.
San Antonio temperatures will rise steadily through the afternoon, likely reaching a high temperature in the low 90s. However, with very high humidity in place, the “feels-like” temperatures will likely reach 95 to 98 degrees. Winds will also be strong, moving in at 15 to 20 mph.
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Shown are the potential heat index values, or “feels-like” temps, across the region Sunday afternoon.
Pivotal Weather
Skies will stay mostly cloudy throughout the day, and there is a chance of a few scattered showers or weak storms during the afternoon and evening. Overall rain chances, though, will stay at 20% or less, keeping much of the region dry.
Storm chances rise this week
Very warm and muggy conditions will stick around on Monday, as high temperatures will once again reach the low 90s across South Texas. By the evening, scattered storm chances will rise, with about a 30% chance of rainfall in San Antonio.
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By late Tuesday, a weak cold front is expected to push through South Texas, sending more widespread thunderstorms into the region. San Antonio storm chances will rise to around 60% Tuesday evening, and some storms could bring heavy downpours.
An active atmospheric weather pattern will continue to send high rain chances into the state through the end of the work week, especially Thursday through Saturday, when several rounds of heavy rain are possible.
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How much rain? The National Blend of Models — which takes into account input from 31 different weather models — shows that the San Antonio area could see between 2 and 5 inches of rainfall over the next seven days, with similar totals also possible across the Texas Hill Country. Isolated totals of over 6 inches may also be possible in a few spots.
These high rainfall totals will not happen all at once. Rather, it will be the total of potentially several rounds of rainfall, mostly between Tuesday and Saturday.
Shown are the potential rainfall totals across South Texas over the next seven days, according to the National Blend of Models.
Pivotal Weather
Many other parts of Texas may also encounter heavy rain. According to model projections, Dallas could see 1-3 inches of rain, while Austin and Houston are favored to see 2 to 4 inches. Even Laredo could pick up 3 inches or more of rainfall throughout the week.
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Flooding will become possible across many parts of Texas during the second half of the week and into the Memorial Day weekend. It’s too early to tell exactly where and when the greatest flood threat will be, but the highest potential for flooding is expected between Thursday and Saturday.
Temperatures will fall slightly during the second half of the week, due to high levels of cloud-cover and moisture. San Antonio highs are expected in the low to mid-80s from Thursday and into the weekend.