- On June 12, 2018
Back in March we posted about the 2018 severe weather forecast which included info from the NOAA about how we could see the same number of severe storms as 2017, if not more, due to the La Nina weather pattern this winter. Forecasters were calling for an early start to the storm season with April being a month with above average tornadoes. Were they right? Not even close.
2018 vs. 3- Year Severe Weather Average
Compared to last year, April 2018 was down 31% in the total number of severe storms. Compared to the three-year average this April 2018 is down 16%. So, the weather forecast calling for more storms due to La Nina conditions was a bit off.
Looking at the historical data from January – April 2018 compared to the same time frame in 2017 you can also see that the total number of severe reports made are also significantly less (look at bottom graph in red). April is the third-most active month for tornadoes, averaging 187 per year during the 20-year period from 1997 to 2016. This is only topped by June with 215 tornadoes and May with 275 in an average year. So, what the hail is going on and where are the storms at?
Slow Start To Severe Weather Season
Many local weather stations and experts are already talking about the slow start to the severe weather season. This past winter also broke a similar record, with the lowest number of severe weather reports made in the past 14 years.
The latest La Niña update came out and shows that the waters continue to be cool off the coast of South America. This is what caused the early April snow in many northern U.S. states. That same cold air is what has kept the tornadoes and severe weather at bay. The good news is that La Niña is weakening, meaning severe weather activity should start to ramp up over the next few months. Once we start tapping into deeper moisture and better storm dynamics, severe weather should start to become more frequent especially by June.
Could the initial 2018 severe weather forecast calling for above average number of storms still be accurate? Maybe. A slow start to the season doesn’t always mean a below average year. Roofers may remember the 2010 Oklahoma season started off slow, but on May 10, 56 tornadoes touched down in less than 6 hours.