April 3, 2012, Dallas Tornadoes and a 1974 Super Outbreak Retrospective

Now that all the excitement is over, here are a couple radar grabs from shortly after 3:00 p.m. EST (1903z) of two tornadic supercells moving across Dallas. Click on the images to enlarge them. I was on the phone with my brother Brian at the time when I took the screenshots. He, my sister-in-law, Cheryl, and my nephew, Sam, live on the eastern side of Dallas. Worried about their safety, I gave Brian a call. It occurred to me that, once the storms had passed, Brian might enjoy seeing a couple of the radar shots that had prompted my concern. The storms fired when moist, easterly surface winds collided with an old, eastward-moving outflow boundary. There's plenty of lift and helicity in that combination, and with good instability and adequate upper-air support, supercells and tornadoes were the result. The event was extremely well-covered, as you'd expect when a major city is in the crosshairs in this age of live streaming and hi-def camcorders. Facebook was abuzz with chatter and images as the scenario unfolded. But it's all finished, and now we wait for official surveys to fill us in on the full scope of storm damage. From the videos and photos I've seen, some of the tornadoes were quite large, but for all that, it sounds like their impact was relatively minor. Of course, in the neighborhoods where homes got damaged or destroyed, it was calamitous, but considering what could have been, Dallas suffered a flesh wound, not a severed limb. So far I haven't heard reports of any injuries or fatalities; let's hope that continues to be the case. One irony of this event is that it falls on a date that affords ample grounds for comparison. Thirty-eight years ago on April 3–4, the infamous 1974 Super Outbreak claimed 319 lives, a figure only recently surpassed by last year's devastating April 27-28 Super Outbreak. One hundred forty-eight tornadoes raked a thirteen-state region in the East and South, and out of that number, six tornadoes were rated an F5 and twenty-four, an F4. Even the 2011 Southern Outbreak, violent, deadly, and prolific as it was, didn't rival that statistic, although it certainly came very close. Dallas today saw nothing like the disasters that unfolded back then in Xenia, Ohio; or Brandenberg and Louisville, Kentucky; or Monticello, Indiana; or Guin, Alabama. That's a good thing. Such benchmarks are not the kind you ever want your own town to challenge, particularly if your town is as large and populous as Fort Worth or Dallas. If you want to get a fascinating and gripping retrospective on one facet of the 1974 Super Outbreak, spend a little time listening to these recordings of the blow-by-blow radio reportage from WHAS as the Louisville tornado moved through the city. Or for a really eerie experience, turn up the volume and listen to this MP3 of the Xenia, Ohio, tornado as it approached and ultimately destroyed the apartment of a Xenia resident, who wisely abandoned his cassette recorder to seek shelter in the basement. And that's enough of that. It's time for me to pull away from the computer and go practice my saxophone.

Intercepting the March 2, 2012, Palmyra-Henryville-Marysville, Indiana, Tornado

Now, while my video from Friday's chase is uploading to YouTube, is a good time for me to write my account of how things transpired down in southern Indiana. The phrase "historic event" rarely describes something good when applied to severe weather. March 2 may qualify as a historic event. The current NOAA tally of tornado reports stands at 117; the final number, while likely smaller once storm surveys have been completed and multiple reports of identical storms have been consolidated, may still set Friday's outbreak apart as the most prolific ever for the month of March. Whether or not that proves true, Friday was unquestionably a horrible tornado day that affected a lot of communities from southern Indiana and Ohio southward. The Storm Prediction Center did an excellent job of keeping track of the developing system, highlighting a broad swath of the eastern CONUS for a light risk in the Day Three Convective Outlooks and upgrading the area on Day Two to a moderate risk. On Day One, the first high risk of 2012 was issued for a four-state region that took in southern Indiana and southwest Ohio, most of Kentucky, and north-central Tennessee--a bullseye in the middle of a larger moderate risk that cut slightly farther north and east and swept across much of Mississippi and Alabama as well as northwestern Georgia. The SPC and NWS offices weren't the only ones keeping vigilance. Storm chasers across the country were watching the unfolding scenario, among them being my good friend Bill Oosterbaan and me. Here are the February 29 00Z NAM model sounding and hodograph for March 2, forecast hour 21Z, at Louisville, Kentucky. (Click on the images to enlarge them.) With MLCAPE over 1,800 J/kg, 0-6 km bulk shear of 70 knots, and 1 km storm-relative helicity at 245 m2/s2, the right stuff seemed to be coming together. By the time the storms actually started firing, those figures were probably conservative, particularly the low-level helicity, which I recall being more in the order of 400 m2/s2 and up. Simply put, the region was going to offer a volatile combination of moderate instability overlaid by a >50-knot low-level jet, with a 100-plus-knot mid-level jet core ripping in. I had my eyes set on southeastern Indiana. The problem with that area is, it's lousy chase terrain along the Ohio River, and it doesn't improve southward. If there was an ace-in-the-hole, it was Bill's knowledge of the territory, gleaned from his many business trips to Louisville. We hit the road at 7:15 that morning, stopping for half an hour in Elkhart so Bill could meet with a client and then continuing southward toward Louisville. Bill was of a mind to head into Kentucky, where the EHIs and CAPE were higher; I was inclined to stay farther north, closer to the jet max, the warm front, and, presumably, stronger helicity. But either choice seemed likely to furnish storms, and since Bill was driving, has good instincts, and knows and likes western Kentucky, I was okay with targeting the heart of the high risk rather than its northern edge. But that plan changed as we drew near to Louisville. By then, storms were already firing, and one cell to our southwest began to take on a classic supercellular appearance. Bill was still for heading into Kentucky at that point, but after awhile, a second cell matured out ahead of the first one. We now had two beautiful, classic supercells to our southwest, both displaying strong rotation. It was a case of the old adage, "A bird in the hand is worth two in the bush"--except in this case, there were two birds, back to back. And I-64 would give us a clear shot at both of them. So west we went, and into chase mode. At the Corydon exit, we caught SR 135 north, headed for an intercept with the first supercell. The two radar captures show the base reflectivity and SRV shortly after we began heading up the state road. A few miles south of Palmyra, we got our first glimpse of a wall cloud maybe four miles distant. That's all there was at that point, and the hilly, forested terrain afforded less-than-optimal viewing. Within a minute or two, we emerged into an open area just in time to see a funnel descend from the cloud. Tornado! The sirens were sounding in Palmyra, providing an eldritch auditory backdrop to the ropy funnel writhing in the distance as we drove through town. The tornado went through various permutations before expanding into a condensation cone revolving like a great auger above the treeline. It was travelling fast--a good 60 miles an hour, at a guess. As we sped toward it, the condensation hosed its way fully to the ground and the tornado began to broaden. It crossed the road about a half-mile ahead of us, continuing to intensify into what appeared to be a violent-class tornado with auxiliary vortices wrapping around it helically. Shortly after, Bill and I came upon the damage path. We pulled into a side road lined with snapped trees, amid which a house stood, somehow untouched except for a number of peeled shingles. The tornado loomed over the forest beyond, an immense, smoky white column wrapping around itself, rampaging northeastward toward its fateful encounters with Henryville and Marysville. The time was just a few minutes before 3:00 eastern time. While I prepared and sent a report to Spotter Network, Bill turned around and headed back south. We had another storm to think about, and it was closing in rapidly. It wouldn't do to get caught in its way. Back in Palmyra, we headed west and soon came in sight of another wall cloud. This storm also reportedly went tornadic, but it never produced during the short time that we tracked with it. We lost it north of Palmyra; given the topography, the roads, and the storm speed, there was no question of chasing it. From that point, we headed south across the river into Kentucky to try our hand at other storms, but we saw no more tornadoes, nor, for that matter, much in the way of any serious weather. Not that there weren't plenty more tornado-warned storms; we just couldn't intercept them, and after giving it our best shot, we turned around and headed for home. Lest I forget: my worst moment of the chase came when I couldn't locate my video of the tornado in my camera's playback files. It seemed unfathomable that I could have horribly botched my chance to finally capture decent tornado footage with my first-ever hi-def camera. After being miserably sidelined during last year's record-breaking tornado season, the thought that I had somehow failed to record this day's incredible intercept just sickened me. Fortunately, there were no sharp objects readily available; and better yet, the following morning I discovered that I had simply failed to scroll up properly in the playback mode. All my video was there, and it was spectacular. Here it is: My excitement over the video was offset by reports of just how much devastation this tornado caused eighteen miles northeast of where it crossed the road in front of Bill and me. Henryville, obliterated. Marysville, gone. Eleven lives lost in the course of that monster's fifty-two-mile jaunt. And similar scenarios duplicated in other communities across the South and East. The death toll for the March 2 outbreak presently stands at around forty. In the face of a mild winter and an early spring, Friday was the inauguration for what may be yet another very active severe weather season east of the Mississippi. We can only hope that there will be no repeats of last year's wholesale horrors. May God be with those have lost loved ones and property in Friday's tornadoes.

Another La Nina for Winter 2011–2012

Snowfalls that paralyzed entire regions. A record-breaking tornado season. An unrelenting summer heat dome that baked much of the nation for weeks on end, coupled with disastrous drought conditions in the southwest. That has been our weather year 2011 to date, courtesy of its La Nina, which commenced in June of 2010 and ended last April. In another month, we can kiss the whole mess good-bye and good riddance. It's not the kind of year a body wants to see repeated anytime soon. But with yet another La Nina winter shaping up, chances are that's what we've got in store. In its typical terse language, NOAA's Enso Cycle: Recent Evolution, Current Status and Predictions sums things up thus:
• La Niña conditions are present across the equatorial Pacific.
• Sea surface temperatures (SST) were at least -0.5°C below average across the central and eastern equatorial Pacific Ocean.
• Atmospheric circulation anomalies are consistent with La Niña.
• La Niña is expected to strengthen and continue through the Northern Hemisphere winter 2011-12.
. The United States needs another La Nina right now the way a sick drunk needs another bottle of Boone's Farm. We're still reeling from the previous episode, and now here comes round two. While no one can predict with certainty how it's going to play out, the generalities are these:

• The north-central CONUS and portions of the Great Lakes down through the Ohio Valley are likely to see colder and wetter conditions.

• The south and southwest can expect warmer and drier weather--not welcome news to those living in West Texas and other places that have already endured week after rainless week this summer.

Also, while you won't find it stated in ENSO literature, statistically, tornado outbreaks east of the Mississippi have tended to occur during La Nina springs. Whether a correlation does in fact exist, circum 2011 certainly seems to corroborate the notion. Let's hope that this new player turns out to be La Nina Lite in terms of its impact. I can't imagine that it will be as nasty as its predecessor, but anything is possible. We're only getting started, and already the Northeast has gotten clobbered with a record-setting winter storm. The plus side is, parts of the drought-stricken West have received a rare and welcome snowfall. That's good, and I hope they get more precipitation, lots more, be it snow or rain. For those of you who pray, this new La Nina is something to enter in your prayer list and keep an eye on. This winter could be another bad one, and storm chasers may once again have their hands full next spring. Let's hope that Dixie Alley experiences nothing like what it did this year. We'll find out five or six months from now.