This November turned out to be Austin’s second-warmest ever and the 12th-driest on record, according to National Weather Service data from Camp Mabry. But with the arrival of December, weather patterns could be changing in the coming days.
The average temperature for the month reached 66.2 degrees, the warmest average in 90 years, but still 2 degrees shy of the November record.
The heat hit early and lasted for most of the month. We hadn’t even made it a full 72 hours into November before temperatures broke a daily heat record, hitting 88 degrees on Nov. 3 and two more times in the next three days. Temperatures reached 80 degrees or higher on 11 of November’s 30 days, weather service data show. All but six days were warmer than 70 degrees.
Troy Kimmel, a University of Texas meteorology lecturer and forecaster, said several factors contributed to the unseasonable warmth and dryness. But Texas and many other parts of the United States were clearly experiencing the effects of La Niña, the seasonal cooling of the waters in the eastern Pacific that can influence weather patterns in the Northern Hemisphere.
A La Niña can shift jet stream patterns – rivers of air in the upper levels of the atmosphere – and cause parts of the Pacific Northwest to be colder and wetter than normal in winter, for instance, and most of the southern United States to be warmer and drier than usual, Kimmel said.
“That water in the Pacific is colder than it is usually,” he said. “And since it’s colder, there’s less moisture to be exported out of that area.”
However, Kimmel and other meteorologists say these jet stream patterns will begin to shift as early as this week.
“We’re going to see a sizable change in the global North American jet stream pattern, and that’s the first time we’ve seen that this year,” Kimmel said. “That’s why we’re anticipating a touch of winter weather.”
Austin could see its first significant precipitation in months late Monday or Tuesday, when forecasters are calling for a 50 percent chance of rain with the arrival of a strong cold front.
November— which might be remembered more for how much of it was spent wearing shorts and sunglasses — definitely was not the month for umbrellas. In a month that normally gets almost 3 inches of rain, gauges at Camp Mabry only reported 0.12 inch — and two-thirds of that measly total fell on Nov. 8.
The city’s other major weather station at Austin-Bergstrom International Airport recorded a similarly unimpressive rainfall amount for November: 0.42 inch. The month was the airport’s ninth-driest since record-keeping began there in 1942, the weather service.
With previous Novembers producing 3.43 inches of rain in 2013, 5.78 inches in 2014, 3.73 inches of rain in 2015 and 3.11 inches last year, Austin hasn’t had a November this dry since 2012, when Central Texas remained in the throes of a major drought. That year, Camp Mabry recorded zero rainfall and the airport reported only a trace of precipitation in November.
The largely rain-free month has left Central Texas under “abnormally dry” or “moderate” drought conditions as of Thursday, according to the U.S. Drought Monitor, a consortium of academic and government researchers. But the arid conditions aren’t limited to the Austin area: About 60 percent of the state, mainly in the eastern half, is in drought, data show.
You might think that November’s dry spell posed a threat to the Highland Lakes, where water-supply reservoirs such as Lake Travis rely on rainfall to replenish it. But as of Nov. 30, Lake Travis was 82 percent full and the water elevation at Lake Travis stood at 669.5 feet above mean sea level — a little more than 3 feet above the historical average for November.
With November behind us, forecasters have their eye on winter, which for meteorologists started Dec. 1 (rather than on the winter solstice).
Kimmel said Central Texas might see a slighter cooler winter in the next few months than they did last winter because that season was the city’s warmest winter on record.
“I don’t think it’ll be as warm as it was last year, but that’s a pretty easy hit,” he said.
Yet Kimmel doesn’t rule out the influence of a warming global climate on how the weather turns out in Austin.
“Is it totally responsible? No. The atmosphere is way too complex to tag it to only one thing,” he said. “It’s usually many things. But a warming of the climate is a factor.”