AccuWeather is reporting today that due to the continuous onset of cold, drier air that’s been keeping southern moisture at bay, the month of March has seen no severe thunderstorm watches issued by the National Atmospheric and Oceanic Administration’s Storm Prediction Center, something that has never happened in the center’s 45-year history.
“We are in uncharted territory with respect to lack of severe weather,” SPC’s Warning Coordination Meteorologist Greg Carbin said in a March 17 press release. “This has never happened in the record of SPC watches dating back to 1970.”
According to the SPC, the center has issued only four tornado watches and zero severe thunderstorm watches from the beginning of 2015 to March 17.
This is less than 10 percent of the typical number of 52 tornado watches issued by mid-March, and with only about 20 tornadoes reported since January, it is well below the 10-year average of 130 for that time period, the SPC reported.
“The biggest reason has been the cold weather remaining over the northern and central Plains and into the eastern U.S.,” AccuWeather.com Senior Meteorologist Dan Kottlowski said. “Over the period of several weeks, the polar jet stream, more frequently, has been dipping farther south.”
The colder, drier air has limited the amount of deep moisture in the South, Kottlowski said, stating that this moisture is key to the formation of severe thunderstorms.
“It is still bleeding drier air into these areas,” Kottlowski said. “This cold has put constraints [on the ingredients] which fuel violent thunderstorms.”
While this can occur through the late winter and early spring, the polar jet stream dipping farther south has had a stronger influence with more frequent surges of cold air than normal in 2015, he said.
There is no one clear reason to explain the lack of tornadoes, Carbin said in the SPC release.
“We’re in a persistent pattern that suppresses severe weather, and the right ingredients — moisture, instability and lift — have not been brought together in any consistent way so far this year,” Carbin said.
However, a change in the weather pattern could occur very quickly.
“We do anticipate a change as we head into April,” Kottlowski said. “It is very conceivable that we could go from very quiet to very active.”
“Patterns can change in a few days,” Carbin said, adding that it is important to be prepared for severe weather when it occurs.
This week, unfortunately, the threat of severe weather will put lives and property at risk over part of the Central states.