Super Outbreak 5 years later: My story and the meteorology (Part 1)

Good afternoon.

It’s been fairly quiet in the Northeast recently as spring has really started to come to life after a late spell of winter. Although significant severe weather is likely this week in the Plains (particularly Kansas and Oklahoma on Tuesday), it should remain relatively quiet in the Northeast and Mid-Atlantic.

That was NOT the case 5 years ago though as much of the country was preparing to deal with the greatest tornado outbreak of our generation. At least 363 tornadoes touched down in just over 72 hours, which was a world record for such a short amount of time and nearly one-third of the number expected in an entire year. The destruction in many communities was heartbreaking, with nearly 350 people losing their lives. In just one week, it felt like all our work to improve weather and tornado forecasting and all the warning and technology available was for nothing, as those kind of death tolls were unheard-of in the modern era and comparable to only the great tornado outbreaks of history. Clearly, we hadn’t worked hard enough. It was like Hurricane Katrina in many ways, which also had a human tragedy unseen in the US in many decades.

From now until Friday, every day I will post recollections and lessons learned from that historic week, as well as my own personal accounts. While most of the attention is placed on the Southeast where many catastrophic tornadoes occurred (and a large part of my story took place), it is also easy to forget that there were dozens of tornadoes in the interior Northeast and Mid-Atlantic as well, making it an impressive outbreak for that region as well. Most were weak, but several were rated up to a high-end EF-2. For me, it has many personal touches that I will explain later, and it was a major catalyst in deciding to go to school and then (after later thoughts) enter the meteorology field for real, which is really happening to me this fall.

sfcplot_sm_20110424

Surface weather map on the morning of April 24, 2011 (Weather Prediction Center/NOAA. The frontal boundary is in place but has not fully matured with pressures still quite high. That will change.

April 24: The first signs of danger

In 2011, April 24 was Easter Sunday. Instead of resurrection and hope, there was a lot of fear developing with the forecast in the week ahead, although the big fear was not yet in stone. The US was in an “interlude” of activity with very isolated severe weather that day as the system producing the St. Louis EF-4 on the previous Friday (and a few other tornadoes) departed, while a new system was preparing to move in. The frontal boundary which would strengthen and act as the catalyst for the outbreak was already in place, but the instability and warmth had not developed yet with no clear low pressure centers or dry lines so it was primarily a rain event that day (with major flooding in parts of the South as well).

The SPC had placed an enhanced risk (using today’s standards) in a large part of the southern Plains, with large hail the main threat and isolated tornadoes possible – basically a typical springtime day in the region. There were a handful of tornadoes in Texas, but all were weak (so a treat for chasers with little damage), as well as some wind and hail in the Mid-Atlantic from the departing system. However, already a moderate risk was issued for Monday, April 25 across the middle Mississippi Valley with strong tornadoes mentioned. Models were in agreement that it was the start of something big – and long lasting. Although there was some divergence and the magnitude was to be determined, it was clear that this was going to be an active week. Forecasts for Tuesday (enhanced risk with mention of upgrades) and Wednesday (large area of severe weather, although specifics still uncertain 3-4 days out) were worrisome as well. There was a slight risk in the interior Mid-Atlantic for Tuesday, primarily for wind at that point.

That said, we had seen similar setups before, and this far out it was clear that a significant tornado outbreak was possible in the week ahead – but we didn’t really get a clear idea yet on how bad it would be, as tornado outbreaks happen almost every year, and there already had been many in the exceptionally active April 2011. Each day from April 14 to 16 produced significant tornado outbreaks from Oklahoma to North Carolina, many of which were strong. Was something similar in store? Or was this a false alarm? (It turned out both thoughts were way off).

Meanwhile, back at home…

It was 3 days before my vacation to Florida which had been long planned. I was very closely monitoring the weather forecast, and knew right away that it was going to be an active week. Due to well-placed off days, we had an opportunity to move up the departure date from Wednesday to Tuesday. However, this time it would not really help us as we would enter the greatest threat area on Wednesday (despite the fact the initially planned route is likely facing weather issues too). We couldn’t postpone the departure date to Thursday, however, due to the fact we had to be in Cape Canaveral by Saturday night at the latest to catch a cruise (which I did not take but my parents and sister did).

Using the SPC discussions as a critical guide, we agree that the forecasts were too vague (it was, after all, over 72 hours away and we were in the Day 4 timeframe) to consider a sudden plan adjustment. Other threats, such as heavy rain/flooding, also had to be considered in any plan change. I decided that we should wait until tomorrow to reconsider any plans, and my parents were in agreement. Let’s let the Day 3 and updated Day 2 come in before making the next plan.

Conclusion

It was clear right away that an active week was in store. But I wasn’t as anxious as I could be, since we have seen the drill before. There is a reason the SPC doesn’t issue High Risks at Day 3 or Moderate Risks at Day 4+. Models need to come in greater agreement and there were many things that could go wrong – poorly timed convection, lack of instability, temporal differences and placement issues to name a few. Also there was little indication yet that the Northeast would be getting more than rain and thunderstorms, with a modest severe threat. Simply put, we were to be aware on Sunday afternoon, but we had little idea yet that this would be such a defining day.

Forecaster (soon to be Meteorologist) Craig Ceecee

Remainder of the series:

Part 2 (Monday, April 25) – The outbreak begins and stronger warnings

Part 3 (Tuesday, April 26) – More tornadoes setting the stage

Part 4 (Wednesday, April 27) – The day everything changed forever

Part 5 (Thursday, April 28) – The last vestiges and initial aftermath

Part 6 (Friday, April 29) – Conclusion, lessons learned and the future

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