CORPUS CHRISTI, Texas — The massive upper ridge that has dominated the southern U.S. much of the summer takes a vacation in the Rockies early this week, allowing isolated showers and thunderstorms for South Texas by midweek. As the upper ridge relocates northwest of Texas, an upper disturbance and its associated surface trough move southward into the northern Coastal Bend by Tuesday. That scenario will enhance the sea breeze and allow isolated showers and thunderstorms, especially on Wednesday. Still, the excessive heat will linger, with heat indices of between 114 and 122 degrees.
Later in the week, the heat ridge shifts into the Central Plains and Mid Mississippi Valley, allowing deep tropical moisture to move into South Texas. Expect only slightly above normal temperatures this coming weekend, with isolated showers Friday through Sunday. Afternoon highs in the lower 100s early in the week will drop back to the upper 90s this coming weekend. Morning lows will remain in the upper 70s to around 80. It will be moderately breezy through midweek, with south southeasterly winds at 10 to 22 miles an hour.
The tropics are mainly quiet in the Atlantic and extremely active in the Eastern Pacific. Two disorganized disturbances in the Eastern Tropical Atlantic have a low chance of development and will remain in open waters. In the Eastern Pacific, Category 3 Fernanda is rapidly intensifying and will be a Category 4 later today. The powerful storm in moving west, away from North America. Newly named Tropical Storm Greg will move into the Central Pacific in a day or two. Still another disturbance off the western coast of Central America will likely become a tropical depression or tropical storm by midweek. It is moving west northwest, parallel to and just off the Central America coast.