Excessive Heat in Marion, Texas

A strong upper-level ridge of high pressure intensified and expanded farther northeast from the Southern Plains into the mid-section of U.S. through much of mid to late August. Prevailing southerly flow south of the ridge maintained persistent Gulf of Mexico moisture across the Four State Region. Strong sinking motion observed beneath this ridge resulted in compressional warming, with temperatures climbing well into the triple digits across all of East and Northeast Texas. Given the limited mixing of dewpoints observed, oppressive heat was observed with heat indices reaching or exceeding 110 degrees throughout much of mid to late August.