COLLEGE STATION – Rains may have eased Texas’ drought situation in recent days, but the big weather story may be the lack of severe storms and tornadoes in the state – down by as much as 90 percent in some areas, according to a Texas A&M University expert.
John Nielsen-Gammon, who serves as State Climatologist and Regents Professor in the Department of Atmospheric Sciences at Texas A&M, notes that conditions have not been favorable for much severe weather and tornadoes this year. The North Texas area, for example, had recorded only five tornadoes by the end of June compared to 76 in 2015.
In an average year, Texas has about 132 tornadoes, but this year the state has had only a handful. Texas’ record year for tornadoes? It was 1967, when 232 pummeled the state.
That record-low trend is also unfolding nationwide: according to the Storm Prediction Center, about 1,400 tornadoes occur in the U.S. each year, but so far this year less than one-half that number have been recorded.
“During the peak of tornado season, from April through June, the average jet stream pattern featured a ridge over the central United States, inhibiting upward motion and thunderstorm formation,” Nielsen-Gammon said.
“But the second tornado season comes in the fall across the southeastern United States, including eastern Texas, and with wet El Niño conditions likely to develop, there will be an elevated risk of tornadic activity in the Southeast. These fall events usually come in the form of outbreaks of many tornadoes at a time. This means that the actual number of tornadoes will depend on the weather characteristics of a small handful of events.”
Regarding hurricanes hitting Texas, he noted that Sept. 10 is usually the peak of hurricane season and the numbers of storms hitting the state historically tumbles after that date.
“Few hurricanes have ever made landfall in Texas after mid-September, and this is because the jet stream starts moving farther south and forcing hurricanes in the Gulf to tend to move toward the northeast rather than toward the northwest,” he added.
“However, Texas does commonly get affected by hurricanes in late September and October – just not hurricanes from the Atlantic. West Pacific hurricanes often make landfall in northern Mexico and their remnants travel across Mexico into Texas. Any chance of strong winds is pretty much toast by then, but the excess moisture and instability can lead to some intense rains across Texas. Notable examples include the 1994 Southeast Texas flood, enhanced by the remnants of Hurricane Rosa, and the heavy rains in central Texas in October 2015, enhanced by the remnants of Hurricane Patricia.”
Recent rains have helped much of Texas recently, and “based on preliminary numbers from the Northeast Regional Climate Center, Texas had already achieved one of its 10 wettest Septembers on record by Sept. 17,” Nielsen-Gammon said.
“The rains will probably continue. Next month, although they don’t have very high skill, most computer model forecasts have Texas well situated for continued above-normal precipitation. Beyond that, the winter and spring are also looking wet at this point, as an El Niño seems ready to develop in the tropical Pacific.”