An additional look at the Joplin tornado, after the assessment report

The NWS assessment report for the Joplin tornado came out last week (see here and here), 4 months after this horribly tragic event. I was glad to see that the authors of the report picked up on the public perception of high false alarms, and their tendency to ignore warnings and sirens because of an optimistic bias and the perception that "they happen all the time" in southwest Missouri. I was also glad to see some discussion in the report about the possibility of different tiers of warnings, and even different siren tones or patterns to get people's attention in situations that are truly more deadly. These are some things I touched on (particularly a two-tiered warning system) in a discussion I posted at the very tail end of July.

Given the broad environment area of sizable low-level shear and large CAPE present at late afternoon over southwest Missouri on May 22, when significant storm rotation was detected on radar in that environment, particularly moving toward a populated area like Joplin, that would have been a good situation for the use of enhanced wording or even a "higher tier" of warning. And, even though the tornado developed very fast on the southwest edge of Joplin 17 minutes after a tornado warning with standard wording had been issued, it seems possible that if more urgent action had been performed rapidly around 5:40 pm when the first tornado reports were coming in (e.g., a "tornado emergency" statement or reissuing of the tornado warning with more urgent wording prompting continuous sounding of sirens at that point), some additional lives might have been saved.

With the Joplin report now out, this is a good time and context to go back and look at the Joplin setting using SPC mesoanalysis graphics, which are generally good estimates of parameter patterns and ingredients useful in various types of weather forecasting. The first graphic above shows MLCAPE (mean-layer CAPE) and 0-1 km SRH (storm-relative helicity) graphics at 20 UTC (3 pm CDT) on 5/22/11 after the first storm had developed in southeast Kansas near Parsons (black arrow). Notice that while MLCAPE was quite large (> 4000 J/kg), 0-1 km SRH appeared rather unimpressive at this point (around 100 m2/s2). The 2nd graphic above shows the same paramaters, but 2 hours later at 22 UTC (5 pm CDT) about 30 minutes before the Joplin tornado. Notice that MLCAPE was still very large, but 0-1 km SRH had _increased dramatically_ ahead of the supercell complex approaching Joplin (black arrow), more than _doubling in value_ to greater than 250 m2/s2!

Looking at a SRH/CAPE scatterdiagram (3rd graphic above), notice how this low-level shear increase moved the SRH/CAPE data point from below the red curve upward to _well above_ it. This trend was very important, probably helped by a surface low forming over southeast KS (4th graphic). This should have been noted by any mesoscale analyst working as support to radar/warning meteorologists in the southwest MO/northwest AR/northeast OK area that afternoon. Even though no tornadoes had occurred yet in the s.e. KS/s.w. MO area, such an increase would be a red flag for considering the use of enhanced wording in warnings (or a higher tier of warning, if such a system were implemented) based on any significant rotations detected on radar in such an environment, particularly if a very populated area (such as Joplin) were threatened.

Let's contrast the Joplin setting with a situation that occurred at midday in Kansas City on 5/25/11, 3 days later. The last graphic above shows CAPE (11 pm CDT) and SRH (noon CDT), similar to the earlier graphics, though SBCAPE (surface-based CAPE) is used due to the "cold-core" nature (500 mb closed low nearby) of the setting where SB lifted parcels are typically more representative of true instability. Note that SRH was quite meager (around 50 m2/s2), and CAPE was less than 1500 J/kg in the immediate Kansas City area (left black arrows in last graphic above), with the resulting position on the same SRH/CAPE diagram above far to the lower left _well below_ the red curve. Although it is quite possible to get small short-lived tornadoes in such settings, strong "cold core" tornadoes are almost always linked to settings with much larger SRH. Indeed, there were 2 or 3 reports of brief weak tornadoes from south to north across the KC metro area, but certainly no significant damage. Compared to Joplin, the threat over the Kansas City area was small in this situation. But tornado warnings with wording not much different than the intial Joplin warning 3 days earlier prompted several people in KC to call my wife Shawna and me in panic to ask what was going on, given that Joplin had occurred only a few days earlier. We told people to take cover and precautions, but that the risk was only a small fraction of what it had been for Joplin. This is an example of a situation where 2 tiers of warnings (and possibly different siren modes) might be useful in conveying the relative threat to the public.

Admittedly, the Kansas City situation on 5/25/11 was complicated by the rapid increase in parameter values and support for tornadoes some 70 to 80 miles east-southeast of Kansas City, where a significant EF2 tornado hit Sedalia just after noon. With SRH in the 150-200 m2/s2 range and SBCAPE near 2500 J/kg in the Sedalia area and southeastward (see right black arrows on last graphic above), the SRH/CAPE potential was very close to the red curve on the SRH/CAPE diagram above, signaling a much greater tornado threat there. So the May 25th situation was not a simple one to assess. But use of the tools above were definitely helpful in indicating the increased tornado threat and tornado risk as one moved well east and southeast of Kansas City.

To be clear, I do understand and know that there are many, many tornado warning situations where it is essentially impossible to distinguish between warning and not warning using radar in combination with environment conditions... in those cases the environments are simply too "borderline" to make such calls given the knowledge and observing situations we have. BUT, there are also situations where tornado environment parameters are clearly impressive as thunderstorms form, suggesting increased risk of death and injury over larger areas. Those are the times when we need to do everything we can to convey the true risk to the public.

I do also know that many people still don't seem to know the difference between a watch and a warning (maybe the term "alarm" instead of "warning", avoiding the "waa.." word sound confusion between the two words, would be better?). So I often get arguments that much of our populace is too "dumbed down" to deal with a 2-tier warning system. But is that really a reason to continue status quo in our current system when today's technology and knowledge can offer more information in many warning situations? That is something to think about.

- Jon Davies 9/26/11

The 8/13/11 Indiana stage collapse -- an example of severe weather safety issues at a large public venue

Saturday evening's stage collapse due to strong gust front winds at the Indiana State Fairgrounds in Indianapolis killed 5 people and finished off a week when several people were killed in the U.S. as a result of thunderstorm winds. On Aug. 7, 1 person was killed in southern Missouri when a tree blew onto their car; on Aug. 9, a UPS driver was killed in northeast Indiana when a tree fell on his truck, and on Aug. 10, a woman was killed east of Tulsa OK when thunderstorm winds destroyed a mobile home (this may have been a brief non-supercell tornado from a bow echo on radar). This all serves as a reminder that severe thunderstorm/squall line winds can and do kill people.

Concerning Saturday's Indiana State Fair tragedy, here's what my wife Shawna posted on Facebook:
"The Indiana Governor called last night's stage collapse a "freak accident". I respectfully disagree. That was a make shift stage sitting right in the path of that gust front. It doesn't take a genius to know it was disaster in the making (especially when you see Ernie Mill's photos of the shelf cloud as it approached). The concert should have at least been delayed once the warning was issued (10 minutes out) with an orderly evacuation AWAY from that stage. Very sad and preventable incident. It's also another reminder that we in the weather community need to continue to educate the public about weather awareness."

I agree... At 8:39 pm EDT, NWS had issued a warning for Indianapolis concerning thunderstorm winds in excess of 60 mph a full 10 minutes before the storm struck the fairgrounds at around 8:50 pm EDT, and severe thunderstorms had been in the area west of Indianapolis approaching for more than an hour before (see radar images above). A shelf cloud (a visual "red flag" to watch for strong wind gusts, see Ernie Mill's photos above) was quite visible as the thunderstorm gust front approached the fairgrounds. A full evacuation wasn't practical or even necessary, but certainly it should have been clear that the _temporary_ stage structure with its top-heavy lights was a dangerous place to be around in strong winds. The deaths all occurred in the first several rows as the stage structure collapsed. Someone at a microphone should have emphatically told concertgoers seated within a couple hundred feet of the stage to at least move back well away from the stage structure _before_ the gust front hit; that much would not have been difficult to do. From this perspective, Saturday's tragedy was preventable and certainly not a "freak accident" or "fluke".

At all public outdoor venues that involve thousands of people, the organizers/managers of the event on-site need to be in consistent touch with a meteorologist or weather-knowledgeable person regarding any potential severe weather that may be approaching, even if it is many miles away yet. And a _clear_ communication line needs to be open to those on stage or in control of the public sound system at the event to let people know where to go in a timely manner before weather hits. While full evacuations may not be practical or possible, people definitely need to be warned and told to move away from dangerous _temporary_ structures that may collapse when gusty thunderstorm winds hit them. That seems like a no-brainer.

- Jon Davies 8/15/11

Do we warn too much? Some thoughts on tornado warnings in this tragic year of tornado deaths...

It's been 2 months since the horrifying Joplin tornado (death toll now 159), and 3 months since the shockingly deadly tornado outbreak in the Dixie states that killed well over 300 people. It now looks like 2011 will be the 4th deadliest U.S. tornado year on record. I don't think most people have any idea how jaw-dropping that is... one has to go way back before a coordinated tornado warning system was in place to find annual tornado death tolls of that magnitude!

When big tornadoes hit cities, there will be deaths. And there have been many large long track tornadoes this year in populated places. But the staggering death tolls this year also raise some questions, including these: Are people getting complacent regarding severe weather preparedness? And do we now warn so much that warnings sometimes fall on deaf ears? A respected nurse at one of the hospitals in Joplin told me, "We get warnings and sirens all the time... we're, like, tone deaf... it's hard to take them seriously." I've heard many similar comments from other people. Severe weather education is a never-ending task that requires continued attention and priority, and getting people to listen and take action is deeply rooted in social science rather than meteorology.

It is noteworthy that, compared to the 1980s, the number of tornado warnings in some parts of the U.S. (such as the Southeastern states) has increased at least seven or eight-fold, according to a recent article in the Birmingham News, while false alarms are averaging close to 80%. I know of no concrete social studies that have examined "warning fatigue" regarding tornadoes and severe weather. Yet I do agree with respected Birmingham TV meteorologist James Spann's recent comments that have stirred some controversy.

I continue to see a number of tornado warnings issued in marginal settings where, based on years of data and increased operational knowledge about tornado environments, the atmosphere can only support, at best, weak or brief tornadoes. In those cases, the threat is considerably less compared to days like the Joplin tornado event this year, and the Dixie Super Outbreak. Yet it is often difficult to discern the relative degree of threat or risk in the text of many warnings, whether read verbatim or presented via media such as television. I know that the National Weather Service (NWS) and television/media meteorologists have a sincere desire to save lives and have the public know about all weather threats. Yet I wonder if we shouldn't reaffirm that we can't warn or cover all severe weather events. Instead, shouldn't we make a stronger effort to emphasize warnings in those weather settings that clearly have potential to be truly dangerous to many people in populated areas? I'm no expert in social science, but with my background in severe weather research, here are some comments from a meteorological perspective.

The first graphic above shows combinations of low-level wind shear (storm-relative helicity or SRH) and instability (CAPE, or convective available potential energy). On the most simplistic/basic level, these are the most important environment ingredients linked to supercell tornadoes based on research over the past 25 years. On this graphic, I've plotted estimated SRH/CAPE points (using nearby RUC model analysis soundings) for 44 tornadoes that were associated with 4 or more deaths over the past 11 years. I've also drawn in a curve suggesting a rough lower "limit" to SRH/CAPE combinations that generally support tornadoes that can kill larger numbers of people; note that all events but one (98%) fell above this curve.

Looking now at a much larger database (2214 supercell soundings I've collected over the past 11 years, 90% associated with NWS tornado warnings), the 2nd graphic above shows the percent and number of both non-tornadic and tornadic supercells (tornadoes shown by EF-scale intensity) falling near and above the red curve in the first graphic, suggesting more favorable SRH/CAPE combinations for strong/violent tornadoes. Notice that, using the discriminating curve suggested by the first diagram, only 17% of the non-tornadic supercells were "false alarms", falling near or above the curve but not producing any tornadoes. But moving over to significant tornadoes (EF2-EF5), notice that increasing majorities of these supercells fell into the more "favorable" area above the curve. Using only this simplistic SRH/CAPE scheme in supercell settings, this suggests workable false alarm and detection rates for supercell tornadoes, not even considering other ingredients such as deep-layer shear, cloud base height, amount of convective inhibition, storm motion relative to surface boundaries, etc., that have been found relevant in tornado forecasting research.

This isn't really new information; forecasters at SPC have used SRH and CAPE combinations along with forecasts of other ingredients for years now when generating outlooks and watches for tornadoes. However, tornado environment ingredients seem to be used less consistently when actual tornado warnings are considered. This is supported by the first column of the 2nd graphic above, where tornado warnings (not shown) were issued for 984 of 1160 non-tornadic supercells, yet the SRH/CAPE environment for 83% of these cases fell below the red curve in the first graphic above. Certainly, supercells in SRH/CAPE environments below the red curve do produce tornadoes, but when they occur, the large majority (80-85% according to my database) are weak (EF0-EF1 intensity). When thunderstorms form and become supercells, it is the environment area above the red curve where the probability of deadly tornadoes increases dramatically.

My point is this: Shouldn't we place a much stronger emphasis on radar-based tornado warnings issued in settings where SRH and CAPE are in the area near and above the red curve in the first graphic above, even prior to confirmed spotter sightings?

There are a variety of ways to work toward this, including better environment awareness by meteorologists (the SPC mesoanalysis page is a great tool in this regard) when issuing and presenting warnings, stronger wording and importance placed on warnings when environments are in the enhanced SRH/CAPE area, and making the public more aware that there are different levels of danger in weather settings.

I know that many of my colleagues in the NWS work hard to incorporate environment information into tornado warning decisions, and that there are many times when it is very difficult to know when to hold back from issuing a warning, or to go ahead and "push the red button". Also, I know that meteorologists in today's media intensive society don't usually get rewarded for not warning in a marginal situation and avoiding a false alarm, but they are ruthlessly scrutinized when a notable severe weather event is missed. I'm not suggesting that we don't warn in marginal situations where tornadoes can still produce isolated damage and threat. I am saying, let's make sure to put the strongest emphasis on warnings in environments where ingredients appear more optimum for stronger supercell tornadoes, and try to be more clear about that to the public.

A 2-tier warning system that would use an enhanced danger "red flag" in larger SRH/CAPE combination situations would certainly be a more radical solution, and require more public education. But this could help hospitals, factories, and public venues make more informed decisions regarding costly labor-intensive sheltering in the more dangerous situations, and possibly reduce apathy from "false alarms". It also might help emergency managers make more informed decisions regarding the use of sirens, maybe running them longer and more consistently in "red flag" situations, or using different siren tones to catch people's attention.

Several of my colleagues have told me the above would be unworkable, and even confusing to the general public. That may be. But I do feel strongly that we can do more to help the public recognize warning situations that clearly have greater danger affecting more people. I can't avoid a strong sense that, with all the information and knowledge available to meteorologists today, we can do a better job conveying true tornado threats to the public and reducing false alarm perceptions that can engender public apathy. I think this is worth at least a look in this tragic year of tornado deaths.

In a future post, I'll discuss some recent example cases that relate to the above discussion.

- Jon Davies 7/30/11

Unusually strong cold-core tornadoes in KS and NE - 20 June 2011

I had intended not to write about so-called "cold-core" tornado settings (see this paper) for quite awhile, as most tornadoes associated with such settings are weak. Given the terrible death tolls from violent tornadoes in 2011, I feel the main focus should be on settings that produce stronger tornadoes and how we might reduce the number of deaths. But the prolific cold-core tornado event on Monday 6/20/11 in northwest KS and south-central/central NE was atypical; some of the tornadoes were strong in intensity (preliminary rating EF3, rare for tornadoes in a cold-core setting), so I felt a short write up might be justified here.

Many cold-core events start relatively early (late morning or early afternoon) due to the strong dynamics and cold air aloft. The 20 June setting was no exception. The first tornado report came near Quinter KS at late morning just northeast of the surface low, and large tornadoes were in progress in the Hill City/Norton area of Kansas by early afternoon (see Mark "Storm" Farnik's impressive photos above near Long Island KS after 2:00 PM CDT, see also David Mayhew's awesome photo above from the same storm; go to this link for an incredible sequence of his images). Tornadoes continued along a corridor into south central NE with this and another supercell, and other tornadoes occurred at late afternoon with yet another supercell in central NE near York. All these tornadic storms were northeast of the surface low near the warm front/dryline interface, a typical focus area for cold core tornadoes with the closed mid-level low and associated cold air aloft not far to the west.

What made this event so prolific with strong rather than weak tornadoes? I modified the RUC analysis sounding at Hill City at 1900 UTC (2 PM CDT, 3nd image above) for surface inflow parcels coming into the tornadic cell north of Hill City at that time on north or northeasterly winds (see surface observations northeast of the surface low on the surface map above at 1930 UTC). This resulted in an unusual amount of CAPE for a cold-core event, on the order of 2500 J/kg (most cold-core events are associated with CAPE values less than 1000 J/kg). In addition, 0-1 km storm-relative helicity (SRH) was sizable, in the range from 200 to 300 m2/s2 within a focused area ahead of the storm. This resulted in large energy-helicity index values (0-1 km EHI greater than 3.0, see 5th image above) in a corridor ahead of the tornadic storm, also unusual for a cold-core event. The sharp trough and tight closed mid-level low moving into the KS/NE area were unusually strong for mid to late June (see NAM forecast for midday above), a time when, unlike early spring cold-core events, large CAPE values can be present with surface dew points in the 60s F or higher. This large CAPE and SRH certainly provided support for larger and longer-lived tornadoes on 6/20/11 than typically associated with most tornadic cold-core events.

NOTE: Cold-core events aren't defined by whether the storms are "mini-supercells"; yesterday's case featured larger storms that were essentially classic supercells because of the larger/deeper CAPE, contrasting with early spring or fall cold-core systems that may have surface dew pointsonly in the 50s F. The important issue is the _pattern_, with the closed low aloft that organizes intersecting boundaries in a fairly narrow corridor ahead of the surface low and cold air aloft as the midlevel system moves east or northeastward, setting the stage for potential rapid tornado formation. This is a common repeating pattern with cold-core systems that produce tornadoes, and can be very useful operationally in anticipating such events.

An additional factor on 6/20/11 was probably steep low-level lapse rates in the vicinity of the tornadic storm at early afternoon over northwest Kansas. On the last SPC mesoanalysis graphic above, notice the axis of steep lapse rates extending through the surface "dry slot" over western KS into the environment of the northwest KS tornadic storm at 1900 UTC, along with plentiful 0-3 km CAPE. This combination could enhance stretching in low-levels that would already be rather strong due to the cold air aloft from the nearby midlevel low, even as cloud bases might rise some with this hotter/steep lapse rate surface air mixing in from the east from the surface dry slot (again, see surface map above). Indeed, many of the tornadoes formed quickly and were "dusty" (see the Mayhew and Farnik photos above), suggesting non-mesocyclone stretching processes similar to "landspouts", but combining with supercell processes involving strong SRH (see SRH field, also in the last graphic above). According to both Storm Farnik's and David Mayhew's descriptions, multiple dusty tornadoes were sometimes in progress simultaneously in close proximity, suggesting that enhanced low-level stretching processes were ongoing in the northwest KS storm environment northeast of the surface low.

Thankfully, there have been no reports of injuries with any of Monday's tornadoes so far, even though damage as high as EF3 in intensity was observed with at least one of the tornadoes in northwest KS.

Thanks to "Storm" Farnik for sharing his excellent photos and descriptions, and to David Mayhew for allowing me to use one of his images. Check out David's awesome and beautiful sequence of shots from this tornadic storm at:
http://davidmayhewphotography.com/~dmphoto/lightbox/index/category/gallery|StormChaseLog|2011ChaseLog|110620NortonKSnew

Jon Davies - 6/21/11

The Joplin tornado environment - poor visibility with large shear & instability

The death toll from last Sunday's horrendous and tragic EF5 tornado in Joplin, Missouri (see my prior blog discussion) is now up to 132 people, according to reports on Friday 5/27/11. As the deadliest single U.S. tornado in over 60 years, it is worth taking a brief look at the storm environment that helped generate it.

The RUC analysis sounding for Joplin at 2200 UTC (5:00 pm CDT, see 2nd image above), an estimate of the environment roughly 40-45 minutes before the tornado struck, showed very large instability (MLCAPE > 4000 J/kg) and quite sizable low-level wind shear, with 0-1 km storm-relative helicity (SRH) near 300 m2/s2. This matched values shown on SPC mesoanalysis maps at 2200 UTC (not shown). On the same SRH-CAPE diagram where I plotted the Tuscaloosa AL tornado environment in a blog post a few weeks back (see 3rd image above), this combination of SRH and CAPE places the Joplin tornado environment in the same general area and magnitude on the diagram as the Moore OK tornado in 1999 and the Greensburg KS tornado in 2007, both rated EF-5 as well. Although the NAM 12-hr model forecast under-represented the energy-helicity index values (EHI, combinations of SRH & CAPE; see 4th image above), it did forecast a good estimate of the pattern, with an EHI maximum indicated over northwest AR and southwest MO. So it is not a total surprise that the tornado was so strong and deadly.

What is a surprise is the huge death toll, which was partly a result of the tornado being rain-wrapped and very difficult to see (see my photo at top above), and the size of the tornado (around 3/4 mi wide) going down through a very populated area. Going back to the RUC sounding above, relatively weak winds of 40 kts or less at storm anvil level (around 300 mb or 30,000 ft and above) probably contributed to the high-precipitation (HP) rain-wrapped nature of the storm, allowing significant precipitation to fall in and around the updraft/mesocyclone area where the tornado was located, rather than being blown downwind away from the updraft. This seems a little unusual for an EF5 tornado, as most such environments I have examined (e.g., Greensburg KS and Moore OK) have had much stronger winds at that level, instead of the hodograph doubling back on itself with weaker winds in the 9-12 km AGL elevation range. This exacerbated the visibility issue on a day that was already hazy and murky with moisture and humidity, and may have fed into the number of deaths as residents could not get a visual sense of urgency until the tornado was almost right on them.

Another possible ingredient that may have helped contribute to the tornado was a subtle WSW to ENE boundary that appeared visible in the low-level cumulus field on satellite at early afternoon across the Joplin area (see 4th image above). As the Joplin storm complex moved across or "phased" with this subtle feature, it might have provided some focus for the low-level wind shear and SRH to help spin up the tornadic circulation. But this is only speculation.

The last point I'll make is the complex evolution of the Joplin storm, as can be seen in the radar images in the last graphic above. The original supercell and mesocyclone formed near Parsons KS, but began to fall apart shortly before 5:00 pm CDT over northern Cherokee County KS. At this time, three new cells were rapidly developing on the original storm's right/southern flank; two of these cells ("A" and "B" in the images above) quickly merged, while the southern-most of these newer cells ("C") generated a new mesocyclone around 5:15 pm CDT that prompted an NWS tornado warning for Joplin proper at 5:17 pm CDT. This new mesocyclone produced the Joplin tornado about 20-25 minutes later as it merged into the complex that had been cells A and B. The relevance, if any, of these complicated mergers and rapid evolutions to the intensity of the Joplin tornado is not immediately clear. It can be said that, with each new right flank cell raining into the one to its northeast and merging into the complex, this probably further created visibility problems that helped make the monster Joplin tornado even more deadly.

This intensely tragic event has turned literally thousands of lives upside down. Please consider making a donation to one of several organizations assisting in the Joplin area. See http://www.cnn.com/2011/US/05/23/joplin.how.to.help.

- Jon Davies 5/27/11

Unfathomable - the 22 May 2011 Joplin tornado

Update, Thursday 5/26/11: The Joplin tornado death toll has risen to 125, making it the most deadly single U.S. tornado since the Woodward OK tornado of 1947. Yet another outbreak of dangerous tornadoes occurred in the Oklahoma/Kansas/Arkansas area on Tuesday 5/24/11, killing several people.

It is now one of the largest single city tornado death tolls in the past 70 years... 89 deaths and climbing. It is the 2nd deadliest tornado event in Missouri history (just behind the 1896 St. Louis tornado in number of deaths). Yesterday's tornado at Joplin, Missouri is yet another massive tragic event in this year of killer tornadoes and huge death tolls.

Shawna and I drove through downtown Joplin minutes before the tornado hit. Sirens were going, but we could not see the tornado, and many people were out and about seemingly unaware or unconcerned. We had been following this storm complex for a couple hours without observing any tornadoes, and though we were a little nervous, we weren't anticipating anything of the magnitude that buried Joplin around 5:45 pm CDT.

We blasted southwest on Interstate 44 to circumvent the approaching mesocyclone on radar that suddenly appeared very strong. As we looked to the north through the trees we caught a brief glimpse of the hard-to-see tornado (see images above, the second enhanced to make the tornado more visible). It was so large and the visibility so poor, that this may have had something to do with why so many people were killed.

Shawna wrote a paper for one of her college classes back in April before the Dixie Super Outbreak on the 27th. In that paper she suggested that, while death tolls from tornadoes have dropped dramatically in the past 50 years due to better warnings and public awareness, that trend might soon begin to reverse again. She noted that "up-close-and-personal" tornado videos may be jading people's attitudes towards the dangers of tornadoes. And, with so many diverse information and entertainment sources distracting people's attention these days, the public may have increasing difficulty "hearing" warnings and grasping the importance of that information through the wall of "noise" produced by our information technology.

Given what has happened in the past month, I wonder if she may well be right. Bonar Menniger's excellent book about the 1966 F5 Topeka tornado, "And Hell Followed With It", details how many people followed and heeded tornado warnings from TV and radio that day (there were only local stations focusing on local information back then). The death toll of only 17 from that evening in Topeka might in some ways suggest a more focused attention and response from the public regarding truly hazardous events back then contrasting with today.

It is clear that the Joplin event was a difficult one to prepare for, with a rain-wrapped hard-to-see tornado forming just west of town when there hadn't been tornadoes from the same storm complex prior to that. And the tornado was huge and violent, around a mile wide going right down through a populated area. But with around 20 minutes of advance warning from the NWS, the death toll is still staggering, and leaves me pondering what could have been done to reduce it. I am so saddened this morning by what has occurred.

I will mention that there were a number of storm chasers who stopped to help with search and rescue in Joplin, including Tyler Costantini and Jay Cazel, Mira Lee, and the Cloud 9 tours group. That's awesome... all those who stopped and helped in the aftermath deserve big credit for doing so.

Shawna's and my thoughts and prayers truly go out to all who have suffered losses in the tornadoes of recent days.

- Jon Davies 5/23/11

The Reading KS tornado - Kansas weather turns deadly on 21 May 201

Severe weather turned deadly suddenly on Saturday evening 5/21/11 when a tornado struck Reading KS (northeast of Emporia) around dark, killing 1 person, injuring others, and destroying a number of homes. Jim Saueressig's photo above shows the impressive storm structure of the Reading storm after dark.

The environment was one of the most rapidly changing that I've seen on Saturday. At late afternoon, the SPC Sig Tor Parameter (STP) was weak across eastern Kansas with marginal values due to both deep-layer shear and low-level shear being rather weak or marginal for tornadoes (0-6 km shear around 30 kts or less, 0-1 km storm-relative helicity/SRH < 100 m2/s2). This is why SPC issued only a severe thunderstorm watch for northeast Kansas. But by dark, low-level winds had strengthened and backed more than expected, causing much larger shear values, both in low-levels and through a deeper layer. This made STP values sky rocket as the eastern KS environment improved dramatically for supporting tornadoes. See the graphics above comparing STP over Kansas at late afternoon (2200 UTC) with just after dark (0300 UTC), and notice the change in wind profiles from late afternoon to after dark on local RUC analysis soundings at Topeka and Emporia.

The tornado struck Reading around 9:15 pm CDT (0215 UTC), and other tornadoes from the same complex continued to be reported during the following 90 minutes after dark. Notice the RUC 0-1 km EHI and low-level CAPE forecasts above for 0300 UTC, indicating strong CAPE/SRH combinations _and_ a surface-based setting after dark, important ingredients for nighttime tornadoes.

Shawna and I stayed in the local area north of Kansas City watching storms on Saturday evening, and were very saddened to hear about the strong tornado that hit Reading. After an enjoyable week of storm chasing with no deadly severe weather in the plains, last night brought things back to sober reality.

- Jon Davies 5/22/11