For most of September, it seemed like the very hot summer was never going to end. Triple digit daytime heat, rain-free weather and frequent breezes continued to allow drought conditions to deteriorate across the Rio Grande Valley. A persistent upper level ridge of high pressure continued to spread from the SW U.S. into the eastern half of the nation through the first half of the month.
Occasional showers developed along the sea breeze and showers and thunderstorms developed along a weak cold front that pushed through the early in the month. By the middle of the month, a piece of a diving trough finally displaced the upper ridge, also referred to as La Canicula (from the occurrence of mid July through late August hot weather with the location of Sirius in the night sky). The ridge began to retrograde west towards Baja California. Despite the necessary ingredients being in place (lifting of warm and humid low and mid level air, a favorable upper level jet pattern, and an area of surface low pressure) widespread rain did not occur.
Only splotchy heavy rainfall fell, with the heaviest rain falling on Friday September 14th across the Valley. Another weak frontal boundary and more seabreeze activity on the 18th and 19th provided spotty, but much needed, rainfall across the Lower and Mid Valley. Tropical cyclones were non existent for the Texas coast through September, held off by very dry air associated with the ridge and its frequent extension into the southern and central Plains states. The only help - though slight - from the tropics occurred from the Eastern Pacific. Remnant moisture from Hurricane Miriam and offspring Tropical Storm Norman (near Baja) provided pockets of heavy rainfall on the 28th and 29th, which would briefly improve conditions across the Rio Grande Plains to begin October.