An unusually quiet March for tornadoes--only 6 so far

After an unusually active January for tornadoes, with approximately double the activity of a typical January, tornado activity dropped to near-normal levels in February, and virtually flat-lined during March. The five confirmed tornadoes in Tennessee, Georgia, and Alabama on Monday, March 18 brought the March 2013 tornado tally to just six. Monday's severe weather outbreak in the south brought hail up to the size of softballs to Jackson, MS, and damage from the hailstorm is estimated in the tens of millions.

Since 2000, the U.S. has averaged 89 tornadoes each March, so we have a long way to go to reach average. The 154 tornadoes last year in March 2012 was the fourth highest March total since records began in 1950 (record: 170 in March 2007.) Records for most and least tornadoes in a month have been set 24 times over the past 60 years. Ten of those records have been set in the past decade--six for the fewest tornadoes, and four for the most, said tornado researcher Harold Brooks last week. In addition, the three earliest starts of tornado season and the four latest have all occurred since 1997, and "We've had a dramatic increase in the variability of tornado occurrence," Brooks said. The jet stream, which plays a key role in tornado formation, has been wildly variable in recent years, leading to the large swings in tornado activity.


Figure 1. The EF-2 tornado with 120 mph winds that hit Meriwether and Pike County, Georgia on Monday, March 18, 2013 was one of just six March tornadoes in 2013. The cell labeled "3" spawned the tornado. Two other supercells are also labeled (cell #1 brought hail to Atlanta's Hartsfield-Jackson Airport.) Thanks go to Stu Ostro of TWC for providing the image.

NOAA's Storm Prediction Center is highlighting only a small "Slight Risk" area for severe weather on Thursday over Northern Texas, and another "Slight RIsk" area on Saturday over the Southeast U.S. The winter-like jet stream pattern we are in is likely to be dominant for at least the next week, and perhaps into April. So, March 2013 has a shot at making the top-five list for the quietest March months on record for tornado activity. Years with fewest March tornadoes since 1950:

1) 1951: 6
2) 1969: 8
3) 1966: 12
4) 1958: 15
5) 1978: 17


Forecasting the End
We're safely past the December 21, 2012 date of the predicted Mayan Apocalypse, so its permissible to engage in a bit of "what if" speculation on how civilization on Earth might ultimately meet its doom. That's the premise of The Weather Channel's "Forecasting the End" series, which begins airing Thursday March 21 at 9 pm EDT. I'll be making appearances in six of the episodes, set to air each Thursday through mid-April. You might hear me say the phrase, "It would be a bad day on planet Earth" more than once during the shows, as the type of events being considered--an asteroid strike, super volcano eruption, gamma ray burst, encounter with a rogue planet, and massive methane expulsion event--would all do very bad things to earth's climate, making human life on Earth a tenuous proposition. The spectacular graphics should make for an enjoyable show.

New Wettest Place on Earth Discovered?
After successfully helping cast down one iconic world record--the bogus 136°F measured at El Azizia, Libya in 1922--wunderground's weather historian, Christopher C. Burt, and weather records researcher Maximiliano Herrera are at it again. Mr. Burt documents in his latest blog post a challenge to the world's rainiest location, which is officially Mawsynram, Meghalaya State, India, with an annual average precipitation of 11,872 mm (467.40”). It turns out that Puerto Lopez, Colombia may be even wetter.

I'll have a new post on Friday.

Jeff Masters