Saturday, April 27, 2013

April 25-28, 2011 Tornado Outbreak Part 3

The 27th wound up being the worst storm day of the outbreak, and the worst since April 3, 1974. The SPC issued a high risk over parts of Mississippi, Alabama, Tennessee, and Georgia for the day, eventually bumping the tornado probabilities in their day 1 outlook to 45%, which more than exceeds the minimum tornado probability (30%) to issue a high risk. 
20110427 2000 UTC Day 1 Outlook Graphic

20110427 2000 UTC Day 1 Tornado Probabilities Graphic
 I mentioned in the last post that storms were firing in western Mississippi late on the night of the 26th. Those storms eventually moved into Alabama. Most forecasts thought that the storms would weaken and not be severe over the state due to a capping inversion. Unfortunately, that was not the case. The storms formed a massive squall line that produced severe damage in Mississippi, Tennessee, and Alabama before dawn on the 27th, causing very severe damage, knocking out power to more than 250,000 people in the state of Alabama alone. The storms also posed the problem of knocking out tornado sirens and NOAA Weather Radio towers across the region, leaving many struggling to get warnings. 

The first round of storms moved out, and more storms began firing in Mississippi. Several tornado emergencies were issued throughout the day, and as one would normally expect when there is a tornado emergency, there were very violent tornadoes heading toward populated areas. I'll post area TV stations' coverage, as well as the tornado emergency bulletins as I come across them today. 

The outbreak on the 27th produced four EF5 tornadoes, affecting most notably:
1. Philadelphia, MS
2. Rainsville, AL
3. Hackleburg, Phil Campbell, and the northern suburbs of Huntsville, AL
4. Smithville, MS and Shottsville, AL

The outbreak produced several EF4 tornadoes, affecting areas such as:
1. Tuscaloosa and Birmingham, AL
2. Cordova, AL
3. Cullman and Arab, AL
4. Raleigh, MS and Uniontown, AL
5. Ohatchee and Piedmont, AL
6. Ringgold, GA and Cleveland, TN

First piece of coverage, starting at 2:00PM, from ABC 33/40 in Birmingham. 
Philadelphia EF5, from Andy Gabrielson


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