April 27, 2011 Tornadoes
On April 27 2011, a significant tornado outbreak affected much of the Central and Eastern United States. Numerous strong and destructive tornadoes hit the states of Alabama, Arkansas, Georgia, Mississippi, North Carolina, Tennessee, and Virginia. As of May 2nd 2011, the National Weather Service (NWS) estimates there were a total of 312 tornadoes during the 24-hour period from 7:00 a.m. CDT April 27 to 7:00 a.m. CDT April 28. The largest previous number of tornadoes on record for a single event occurred from April 3-4, 1974, with 148 tornadoes. The April 27th event was the second of back-to-back High Risk days. The Storm Prediction Center does not issue High Risks frequently. (Between 2000 to the year 2010, there was an average of about 4 High Risk severe weather days annually.) With a death toll well exceeding 300, the April 27th outbreak was one of the worst on record. In fact, it is the deadliest outbreak since the beginning of modern forecasting (1950). Several key ingredients came together perfectly to result in a severe weather outbreak of such magnitude. (Take a quick look at the image on the left.) 1. Warm Temps & Deep Gulf Moisture In Place – the overall pattern had been stagnant for several days which led to deep moisture and above-normal temperatures establishing itself across the region. 2. Cold Air Aloft – temperatures were very cold aloft as a deep trough ejected from the Rockies and into the Central and Eastern United States. The contrast in the temps from the surface to the upper-levels created moderate to high instability across a large corridor, providing ample “fuel” for severe storms. 3. Strong Upper-Level Winds – winds aloft were very strong to even extreme with a 100+ kt jet streak punching into the Mid-South and Tennessee Valley. 4. Surface Cold Front – the system responsible for this outbreak dragged a cold front through the region which provided a source for convergence. The outbreak began early on with morning convection that had previously affected the Southern Plains on the 26th. Dozens of Tornado Warnings had been issued by the NWS prior to 11:00 A.M. CDT. The main event, however, did not begin until mid afternoon when surface temps began to heat into the 70*F’s and 80*F’s. By 4:00 P.M. CDT, several tornadoes had been reported in a corridor from Mississippi through southeastern Tennessee. By 6:00 P.M. CDT, the outbreak was in full swing with numerous Tornado Reports saturating the states of Mississippi and Alabama. This is the time-frame when the recently upgraded EF-5 tornado struck the town of Smithville, Mississippi. This is the first EF-5 tornado in Mississippi since the Candlestick Park tornado (near Jackson, MS) on March 3rd 1966.Another violent tornado caused devastation in Tuscaloosa, Alabama in the afternoon hours of the 26th. The National Weather Service is still surveying the damage from this tornado, so no preliminary ratings have been issued for this tornado. (I will update this once more information becomes available.) A video, along with some radar images, of this tornado are available below. The afternoon and evening severe storms continued their eastward trek into Georgia, South Carolina, North Carolina, Virginia, and West Virginia overnight. The brunt of the severe weather outbreak ended after midnight with only a few tornadoes reported in the pre-dawn hours Thursday, April 28th. To see the Tornado Warnings that the NWS issued on April 27th, see the above image. (above-right image courtesy of Victor Gensini)
This outbreak will be remembered by many as one of the worst days in their lives. The state of Alabama had roughly 2/3rds of the fatalities of the April 26 2011 tornado outbreak. The state with second highest fatalities was the state of Mississippi. The destruction that these tornadoes did to towns across the South was so significant that it will take weeks to assess all of the damage, and months to recover from this tragedy. On May 2nd, 2011, NOAA released a statement regarding the number of EF-3+ tornadoes that occurred on April 27th. Ongoing (preliminary) surveys by the NWS revealed that 2 EF-5 tornadoes, 11 EF-4 tornadoes, and 21 EF-3 tornadoes struck the South on April 27, 2011. Several more strong tornadoes will be added to this preliminary list over the days and weeks to come. (left image courtesy of Earl Barker)
-This article will be updated frequently as more information becomes available, so check this page often for the latest information.
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12-Hour Radar Loop (10:00 A.M. CDT – 10:00 P.M. CDT)
Tuscaloosa, Alabama Tornado -Video
Tuscaloosa, Alabama Tornado – Base Radar 7-Image Loop
Tuscaloosa, Alabama Tornado – Base Velocity 7-Image Loop
Alabama Tornado Tracks
-Article last updated: May 2nd 2011