While Boston and other New England cities have suffered through their snowiest seasons, other parts of the country have some unexpected good news to go along with the record-breaking winter conditions.
All that cold air and a stuck weather pattern are keeping tornadoes to historic lows so far this year.
March is typically a transitional month, where warm moist air from the Gulf of Mexico collides with cold Arctic air to produce severe thunderstorms and tornadoes.
This year, however, the jet stream pattern responsible for all the cold air and snow in the East remains stuck in more of a winter mode.
“We’re in a persistent pattern that suppresses severe weather, and the right ingredients — moisture, instability and lift — (have yet to come together),” said Greg Carbin, the Warning Coordination Meteorologist with the Storm Prediction Center in Norman, Oklahoma.
The group is responsible for issuing the tornado and severe thunderstorm watches that warn the public of impending severe weather. So far this year it’s been extremely quiet.
By this time in mid-March the center would have issued 52 tornado watches nationwide. This year they have issued a paltry four.
Both January and February were well below normal. March has been even quieter. At a time where the tornado season usually ramps up considerably, there has not been a single report this month of a tornado.
“We are in uncharted territory with respect to the lack of severe weather” Carbin said.
In fact if we make it through the entire month of March without any tornado reports it would be a first, according to the center.
There have been around 20 tornadoes reported since January 1, well below the 10-year average of 130 for the period from the beginning of the year until mid-March.
This year comes on the heels of what was has been a welcome lull of tornadoes across the United States the past several years. In 2014, we ended the year with a count of 881, well below the average of 1,253.
Meteorologists don’t fully understand why we have seen the recent drop in tornadoes, but one possible answer is the development of El Nino, a warming in the equatorial Pacific, which can influence weather patterns globally.
Recent studies point to lower tornado counts in the United States during these events. The National Oceanic and Atmospheric Administration recently said that a weak El Nino had developed.
So while all agree this is good news so far this year, it is clear that it is no guarantee that the rest of the season will remain this quiet. Weather patterns can change quickly.
In 1984, for instance, there was a very similar slow start through mid-March and the number of tornadoes ended up well above average by the end of June, according to data from the storm center.
It’s also important to note that even in years where the tornado counts are low, you can still have very violent tornadoes — 2013 being a perfect example. The year ended being roughly 30% below normal for the number of tornadoes, yet included some of the strongest tornadoes on record. The twisters in Moore and El Reno, Oklahoma, occurred in May of that year with devastating results.
