Strange Severe Slump

Map of all severe thunderstorm and tornado watches issued by the Storm Prediction Center from March 1-23, 2015. That's right, there were none.  (Storm Prediction Center)

This is a map of all the thunderstorm and tornado watches NOAA's Storm Prediction Center posted in the U.S. from March 1 to March 24. Notice it's blank? Yeah. That's weird.
"This has never happened in the record of SPC watches dating back to 1970," said Greg Carbin, Storm Prediction Center warning coordination meteorologist in a SPC. "We are in uncharted territory with respect to lack of severe weather."
March 2015 ended with only 10 tornadoes nationwide, the fewest in any March since 1969. Over the previous 20 years, 78 tornadoes have touched down in March. This followed a February with only three tornadoes.
A jet-stream pattern suppressing warm, moist Gulf of Mexico air from making it into the central and eastern U.S. helped to put a lid on severe weather from January 5 through March 23. The virtual absence of any severe thunderstorms deep into March was odd, to say the least.

https://weather.com/storms/tornado/news/lack-severe-tornado-watches-march-2015