A Dozen Texas Tornadoes Leave Lasting Impression

The Dallas-Forth Worth area was hit by at least two large and violent tornadoes Tuesday afternoon and there were reports of maybe a dozen more throughout the state, according to the National Weather Service and newswire reports. Weather Service damage assessment teams are surveying the area and will determine the tornado count and preliminary strength estimates later today. One tornado has already been estimated at EF-3 strength on the Enhanced Fujita Scale.

Local Dallas-Fort Worth television stations captured incredible video of two tractor-trailer trucks being picked up and tossed in the tornado on Tuesday.

As of Wednesday morning there were reports of some serious injuries, but remarkably, no deaths. 

The Dallas/Fort Worth International Airport cancelled nearly 400 flights and American Airlines shut down all of its flights out of the airport late Tuesday. Large hail pelted aircraft parked at the terminals, causing lingering delays as planes are inspected for hail damage. Hail can seriously damage the metal skin of aircraft and force airlines to make costly repairs, and American Airlines had reportedly taken at least 90 aircraft out of service temporarily for inspections.

One tornado passed perilously close to the airport, and at one point the FAA weather portal read that planes were being delayed due to “Weather/Tornado,” which is a rare alert message for a major U.S. airport. 

The images captured by Dallas area residents were startling, as the tornadoes and large hail swept through the metroplex. The twisters produced spectacular images as local TV stations caught 16,000 pound tractor-trailer trucks being tossed into the air. 

Tuesday's thunderstorms were anticipated. John Nielsen-Gammon, state climatologist for Texas, said severe weather had been predicted for the Dallas area. The advanced warnings and wall-to-wall local TV coverage very likely saved lives, weather forecasters said.

Enhanced satellite shot of of severe thunderstorms approaching DFW Airport on Tuesday. Click on image for larger version. The blackish marks represent overshooting cloud tops, indicating the strongest thunderstorms. Credit: U.Wisc/CIMSS.

The National Weather Service's Dallas forecast office issued a statement showing possible tornado tracks from yesterday, and information on the region's extensive tornado history.

The main trigger for the storms was a strong upper level low pressure system that moved into Texas from New Mexico on Tuesday.

According to Kevin Roth, meteorologist at The Weather Channel, more extreme weather may be headed for the lower Mississippi Valley and Tennessee Valley on Wednesday as severe thunderstorms are in the forecast. The Storm Prediction Center also said Alabama, Arkansas, Georgia, Louisiana, Mississippi, North Carolina and Tennessee were at risk for severe storms that could include strong winds and hail, and possibly tornadoes, although the tornado threat is not as significant as it was on Tuesday.

Annotated map of sea surface temperature departures from average on March 28, 2012, showing unusually warm waters in the Gulf of Mexico. Gulf water temperatures typically climb rapidly during Spring. Credit: NOAA/CPC.

One possible contributing factor to the severe weather is the presence of unusually warm sea surface temperatures in the Gulf of Mexico. Moisture from the Gulf is a key ingredient for the severe thunderstorms that spawn tornadoes each spring, but right now, water temperatures are running up to 2°C above average in some spots, which provides added moisture for storms to tap into, enhancing atmospheric instability. Interestingly, above average sea surface temperatures were also implicated as one of the many factors behind last spring's devastating tornado season that left hundreds dead and billions in damage across the South.