Just around 8 pm tonight, Tropical Storm Don limped across the Texas coast near Baffin Bay, not with a bark, but a whimper. The storm that for days seemed destined to drench us with much-needed rain barely made a dent in our record drought. It seemed like the perfect scenario, a moderately moving tropical storm, not expected to become a hurricane but potent enough to trigger steady rain. So, what happened?
The large ridge of high pressure that has been keeping us oppressively hot for weeks was a key player into Don's movement and potency. When the storm formed Wednesday off the Yucatan peninsula, it looked quite healthy. It was moving into very warm Gulf water and into an area of relatively light shear. The high pressure cell that kept us hot was forecast to shift a little and move into the southeast U.S. Problem was, it moved too far south and its strong easterly winds built into the central Gulf near the path of Don.
By Thursday night, it became clear that Don was being "sheared"; that is to say that strong easterly winds aloft were shifting the storms from Don's center. It had a very lop-sided appearance and the center of the storm was north of the strongest thunderstorms. On Friday, this pattern continued as Don quickly wobbled toward the coast, even further south than originally thought.
We did see some rain, though. Here's a breakdown from our trusty WeatherBug gauges from storms that blossomed in the morning and again during the afternoon Friday:
Even though Don is now a distant memory, we could still see some pop-and-go showers this weekend, especially Saturday. The atmosphere is very moist and with a little heating you may be dodging some drenching downpours for the first half of the weekend. By Sunday, though, the high pressure ridge that steered Don away from us returns along with triple-digit heat and possibly our first heat advisories. The heat index will climb over 108° early next week, a dangerous threshold for Houstonians.