Tag Archives: 2011 severe weather season

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Was the Joplin Tornado the Deadliest We Can Expect?

Meteorologists and weather-watchers are bidding the year 2011 a less-than-fond farewell.  While it was certainly a banner year from the point of view of storm chasing—6 EF-5 tornadoes, 17 EF-4s, and many of them highly photogenic, as the dozens of home videos on Youtube illustrate—it was a catastrophe in terms of the human impact.  With 552 fatalities, this year is tied for the second-deadliest tornado year in the U.S.  The death toll is an order of magnitude greater than even most of the “bad years” of the 1975-2010 period.  Two events are primarily responsible for this:  the April 27 Dixie Super Outbreak, which killed over 300 people (breaking the 1974 Ohio Valley Super Outbreak’s grim record by a hair), and the Joplin, MO EF-5 tornado, with approximately 160 fatalities.

With the 2011 Super Outbreak, meteorologists are starting to work out an approximate historical return period for these large-magnitude events.  Before the 1974 event, the last comparable event occurred in 1936, with an outbreak popularly known as the Tupelo-Gainesville outbreak for the violent tornadoes that occurred in Mississippi and Georgia.  It seems that these huge events occur approximately every 35-40 years.  Obviously, a comparable event could occur next spring, but statistically, it seems that they are a 35- to 40-year event.  And, given that the 1974 Super Outbreak and 2011 Super Outbreak saw comparable death tolls, I think we can also estimate what the human toll for such an event will unfortunately be as long as the affected communities have unsuitable safety options for EF-4 and EF-5 tornadoes.

The Joplin tornado is a different beast.  We do not have a comparable modern event.  Individual tornadoes in 1953 killed over 100 people in Waco, TX and Flint, MI, but that year was something of a catalyst of public outrage, for a third tornado in Worcester, MA killed 94 people.  Public sentiment that year was essentially, “DO something so that this never happens again!”  And for 57 years, no single tornado in the U.S. did kill over 100 people.  Then… it happened again.

Was the Joplin event a worst-case scenario?  Is this the deadliest (give or take) that a single tornado can actually be now?

I think the answer to the first question is a guarded “yes,” at least for the specific case of a tornado striking a city.  The tornado was about as strong as they come; its winds were estimated to be up to 250 mph.  They can get more intense than that, but it doesn’t make a lot of difference in terms of structural damage.  The tornado rapidly intensified precisely as it entered the heavily populated regions of Joplin, and it passed right through residential and commercial shopping areas—the worst areas it could strike.  Examination of the track shows that there was also a pretty large corridor of EF-4 and EF-5 tornado damage, which would be expected for a wedge tornado.  Sometimes the area of violent damage is comparatively small, but this was not the case with this tornado.  Storm cellars were rare in this area, making survival above ground mostly a matter of good luck.  The tornado was also rain-wrapped for much of its existence.  In terms of the storm’s power and the location of impact, you can’t get much worse than this.  However, I should note that it occurred on a Sunday.  Some have argued that if it had happened at the same time of day on a work day, it could have been worse.  We don’t know for sure, and let’s hope we don’t find out.  I tend to think it probably would not have been much worse, given that residential areas (not a likely area for commuters to be stranded) and the shopping district (which probably would get more foot traffic on weekends than work-week afternoons) were such a large part of the damage zone.  In my opinion, the Joplin tornado was essentially a worst-case scenario for a tornado striking an urban area.  A comparable tornado striking an urban area probably would have a comparable human toll.

Unfortunately, the second question—is the death toll of ~160 the highest we could see for a single tornado in the modern era—has a different answer.  There are two ways that a single tornado could kill a lot more people than that.

One is the possibility of a weak, poorly-built or dilapidated high rise building taking a direct hit from a violent tornado and collapsing with a lot of people inside it.  Generally, these buildings are not supposed to collapse even in EF-5 events.  Images of collapsed high rises on hurricane landfall sites are misleading; these buildings mostly had shallow foundations and were undermined by the storm surge.  They were not blown over by wind alone, and storm surge is obviously not a factor for tornadoes.  The St. John’s Hospital building in Joplin took a direct hit from the tornado when it was at EF-4 intensity and it did not collapse.  However, a poorly-constructed or dilapidated one could.  (As an aside, one does have to wonder about the possibility of a tornado tearing up ground several feet deep, as happened in the EF-5 tornado on April 27 in central Mississippi. This could definitely undermine a slab foundation on a house, resulting in the foundation being ripped from the ground—the supposed hypothetical “F6 intensity” signature that one heard bandied about prior to the adoption of the Enhanced Fujita Scale.  However, high-rise buildings have much deeper foundations than residential homes.)

The other possibility is that of a violent tornado striking a crowded spectator event, such as a sports game, a fairground, a speedway, etc.  This possibility has been discussed at length by meteorologists such as Dr. Roger Edwards of the Storm Prediction Center.  It’s almost happened before, in fact; in 2008 an EF-2 tornado in Atlanta, GA struck the Georgia Dome while a basketball game (involving my college team) was going on.  It had gone into overtime, so people were not milling around outside.  Still, there are videos from that event of pieces of the roof collapsing and falling to the floor while the spectators were left to fend for themselves in the stands.  A stronger tornado could very easily have taken that roof off.

So yes, although the Joplin tornado was very likely a worst-case event for a tornado strike on a city, thereby representing an approximate limit on fatalities for that type of disaster, the potential exists for individual tornadoes to kill far more people than that in a different sort of disaster.  Let us hope that we can deal with the infrastructure and the safety considerations of large venues so that these greater disasters do not occur, either in 2012 or years to come.

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NWA 2011: Thoughts About Tornado Warnings and the Casualty Count

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I attended the National Weather Association’s conference in Birmingham, Alabama, for two days.  Toward the end of the second day, the main focus of the talks was the terrible death count from tornadoes for 2011, and most of the speakers were coming at the problem from the perspective of social science such as psychology.  It is understandable that people would want to better understand what happened in an anomalous, outlier year such as 2011.  It is understandable that people would want to find out if the catastrophe was a result of factors that can be easily changed, and that they would even be biased toward that hypothesis.  (One presentation even mentioned the “optimism bias”—a concept that seems a bit strange to me as a natural pessimist, but I can readily see that it would exist in most people, and I would say that this is a perfect example of it.)  My intention here is not to call anyone out.  However, I think that a lot of the research is, frankly, barking up the wrong tree.  There are also some very serious flaws with some of the studies themselves.

The bulk of the research involved surveys of people from the areas that were impacted by tornadoes in 2011.  The surveys contained questions about NOAA watches and warnings (whether people received them, how they received them, whether they were understood) and people’s responses to these messages.

Here are some points I took away from the social science presentations:

  • An overwhelming majority of people in impacted areas did receive warnings.
  • A very small minority of them immediately went to shelter after receiving a warning from the first source.
  • A rather large plurality sought out additional information from TV, the Internet, or personal confirmation to determine if the tornado actually existed and would potentially affect them.  This was more likely in people with higher levels of education and in people who knew more about the weather.  (I would like to note here that this is exactly what I did when the east-central MS EF-5 tornado of April 27 was heading my way.  I did not immediately barricade myself under the stairs when I heard the warning.  I looked at radar to identify a probable debris ball signature and plotted its projected path to go right over my house.  I then grabbed my cat and got out of town.  The tornado lifted, but if it had stayed on the ground, I could have been killed as a result of following the canned advice rather than reasoning out the best course of action for myself!)
  • A minority of people chose to completely ignore a warning.
  • When asked how likely they, personally, thought it was that their area (of what radius?  I don’t recall if it was stated) would be significantly impacted as a result of bad weather mentioned in a warning, the most common answer was less than a 25% chance.  The social scientists said that they wanted people to guess a nearly 100% chance, but in fact, the scientifically and statistically correct answer was less than 5%.  Interestingly, this arguably refutes the “optimism bias” argument in that people did give a more pessimistic judgment of their risk level than was really the case, just not pessimistic enough to suit the social scientists.

The social scientists seemed to be dismayed by the fact that people were less likely to immediately dive for cover the more educated and weather-savvy that they were.  Needless to say, this is an odd message to deliver to a room full of meteorologists (many of whom actively seek out bad weather in their vehicles).  What is the point here?  “Ignorance is strength,” to quote from Orwell? Let alone that people can’t exactly become less weather-savvy, less educated, or more paranoid about the personal impact from a storm if they already know better.  This is an example of trying to close the barn door after the animals have escaped.  These things are what people do, and with the proliferation of web phones with more and more features that allow people to have access to information virtually anywhere, these behaviors are only going to become more common.  This means that they are the behaviors that must be worked with and planned for.  Trying to force people into a state of unnecessary and statistically unwarranted fear is not going to work.  Nor is it a good idea to try to bully people into not seeking out information and using cognitive reasoning.  I’m no social scientist, but I can tell you that if this is attempted, the most likely reaction is a rebellious contempt for “the government” for “trying to make us not question, not think for ourselves, and do as we’re told.”  I would be just about willing to guarantee it.  It could backfire badly.  People ultimately have to be responsible for their own decisions.

Furthermore, there was absolutely no evidence given that people who sought out more information first were more likely to be injured or die in an event, and obviously the survey methodology required interviewing people who did not die.  Knowledge about what the people who died did must come from people who were with them and survived.  However, I never even saw that there was a distinction made between the group of people who were in the path of the tornado and were uninjured or had only minor injuries, and those who were severely hurt or killed.  It would have been useful to find out if the people who were severely harmed did anything differently from those who were more or less okay.  Given that at least one of the surveys was conducted via e-mail shortly after the event in question (the Tuscaloosa tornado), I would expect that there would be very few people who were severely injured who even participated in it, because they would have been in the hospital.  In effect, the social scientists gathered statistics about a control group and presented it as though it represented the experimental group.  In this situation, the statistics about behavior patterns following a warning mean nothing in themselves.  There is nothing (survival/non-survival, minor/major injury) to correlate them to.  Implying that these behaviors caused the death toll to explode is unsupported speculation.  The one survey I saw that definitely interviewed people who had lost loved ones or who were severely injured was conducted in Smithville, MS, and these authors did not make any wild inferences about how seeking out additional information had led to the deaths.  There is simply no data support for it.  The only situation where it might make a difference is when the lead time is basically zero and every second counts, which was not the case in the April 27 tornadoes or the Joplin tornado.  (I had a lead time of about 25 minutes, which was enough for me to get my cat and laptop and go 18 miles away.)

There was one data omission that is, in my perspective, more important than any behavioral survey.  One table that I did not see in any of the social science presentation was this one:

F Scale Killer Tor Fatalities
F0 1 1
F1 3 4
F2 15 24
F3 23 76
F4 13 160
F5 6 282
F? 0 0
TOTAL 61 547

(Credit to the Storm Prediction Center: http://www.spc.noaa.gov/climo/torn/fataltorn.html)

That is, 95% of all tornadic deaths this year occurred in EF-3 or higher tornadoes, which will destroy most or all walls in a house.  EF-5 tornadoes can even expose the basement and descend into it (it is a myth that the funnel would magically stop at the ground level if an open hole existed for it to twist into), sucking people to their deaths.  And it gets even more significant when you dig deeper into the data.  A look at the list at the top of that page shows that only 4 of the deaths from EF-2 or weaker tornadoes occurred in permanent houses.  I don’t know exactly what happened there, but it could have been extremely bad luck such as a tree falling on the house, a piece of heavy furniture, or a piece of timber causing injury.  It could have been a weak structure.  The point is, this is very rare.  The rest of the deaths in EF-2 and weaker tornadoes were in trailers, vehicles, outdoors (all highly dangerous places to be in a tornado) or were unknown.

I respect the research into this year’s terrible tornado casualty count.  It is important to determine exactly why this occurred, and one question that did need to be answered was whether it happened because of bad decisions.  This is the question that the social scientists have attempted to answer.  I simply disagree very strongly with their apparent conclusions, as I think they are unwarranted by the questionable research methodologies, and are little more than speculation.  My contention is that the catastrophic death toll is directly attributable to major, violent tornadoes, the kind that obliterate entire homes, happening to occur in a lot of populated areas this year.  In short, it was a statistical outlier year.  This classification does not address the underlying structural problem of the Southeast, which is that effective storm shelter is not commonly available for the most violent events, but that’s not an easy problem to resolve.  Unfortunately, in my opinion, it is this hard problem, rather than comparatively easy ones regarding bad decisions, that must be answered if this type of death toll is to be prevented from ever happening again.

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What’s Going Wrong?

This year has had a truly terrible human toll from tornadoes. The current fatality count, approximately 500, is an order of magnitude larger than the average for an entire year. It is to be hoped that this number does not substantially rise, but we do have June, the tropical season (which is expected—and I agree—to be quite active and have a higher than average risk of U. S. hits), and the cool-season secondary severe weather peak. However, this figure is horrible enough even if these periods of higher risk produce absolutely no damaging or fatal tornadoes. Something went very wrong this year, something that has not gone this wrong in almost 60 years, and it is important to determine what it was.

Having followed the stories in a fair amount of depth and from multiple sources, I have developed some suspicions of my own about what some of the problems were. These are problems that either appeared in multiple situations or that appeared in sites where high concentrations of deaths occurred. Other people may form their own opinions, but in whatever analysis of 2011 that takes place (and you can just about guarantee that something of the kind will be done), I hope that the following issues are seriously examined.

1. Safety recommendations for urban residents.
One ugly lesson we have had forced on us this year is that, contrary to long-standing myth about cities being safer than rural areas in tornadoes (perhaps because of the idea that buildings will provide resistance?), a city may well be the worst place one can be in a violent tornado. Even in the age of high-resolution Doppler radar, real-time chaser and spotter reports, live coverage, and 20-minute lead times for warnings, we now know that an EF-5 tornado striking an urban center can result in a triple-digit death toll, as happened in Joplin, MO. It is easy, in retrospect, to understand why a densely packed urban area may be the worst possible place to be. Other than high-rise office buildings, there is no safe place to be. High-rises, according to the EF-scale, will not be demolished even in an EF-5; the maximum expected damage is “permanent structural deformation.” However, directing everyone to the nearest tall office building is a ridiculous “safety” recommendation, needless to say.

What are some other problems with urban areas? Many buildings in the central business district, like fast food restaurants and small businesses, are not constructed to withstand anything like a tornado, and they are simply not safe places to be. Big box retailers will contain very heavy stock that is piled high, providing plenty of potentially deadly missiles. Vehicles are everywhere, and they will become airborne. Designated tornado shelters, which some communities do have, would be useful only if people flocked to these sites well in advance of an actual tornado, because congestion on the roads could result in mass fatalities. Storm cellars would be all but nonexistent, and basements are limited in spatial extent and would be directly beneath the houses, which puts anyone taking shelter therein at risk of exposure to tornadic winds and suction if the house is removed. There is no easy way to get out of danger; traffic congestion will occur if people try to evacuate en masse, putting people in possibly even greater danger than they would have been if they had stayed put. And, of course, cities will have more debris than any other type of community.

We need to seriously consider what kind of safety recommendations can reasonably be given to people who live in town—if any. It is highly uncommon for cities to be struck by EF-4 and EF-5 tornadoes, but it can happen, and the buildings do not provide friction-based wind resistance that would mitigate the effect of violent winds. The situation needs to be looked at to see if any sort of useful specialized safety advice can be given to urbanites.

2. Vulnerability of cell phone networks.
Sometimes when tornado victims are quoted in the news as saying “there was no warning,” what they mean is that they, personally, were not aware of the situation. However, every fatal tornado this year except for one occurred within a tornado watch (link), and that one, an EF-3, occurred within a severe thunderstorm watch. I do not want to sound callous, but there is a responsibility to be weather-aware, which includes awareness of tornado watches and warnings. The outbreaks were all extremely well forecast. Most warnings this year had lead times of 20 minutes or so. In these situations, it is simply inaccurate to say that there was “no warning.” It is passive-aggressively blaming the Weather Service for one’s own failure to be aware.

However, in some cases, there was a legitimate lack of warning, though this is not the failure of the Weather Service. These instances involved the failure of the power grid and the cell phone network, taking down any means by which one might receive weather warnings other than a battery-powered or hand-crank radio. This occurred in some of the small towns that were overrun by the extremely violent EF-5 tornado that traversed northwest Alabama on April 27. I think it also occurred in one of the EF-4 tornadoes of the same day. This is a real problem. Most new phones have the ability to function as handheld PDA, music player, portable gaming device, organizer, Rolodex, e-mail, Twitter, Facebook, and even web browser. With this kind of capability—and none of it dependent on a steady AC/DC power supply—it is easy to understand why people would be reluctant to buy a portable radio. They depend on their phones, and with good reason. However, the cell phone network is clearly vulnerable. If there is significant damage to a tower, down the network goes. This goes for other disasters, including terrorism. The problem needs to be examined to see if these towers can be made more robust. Severe weather outbreaks usually have more than one round, and areas that saw their power and communications knocked out by one (even relatively benign) event can be extremely vulnerable later on.

3. The DTV conversion.
I had a bad feeling about this as soon as the DTV changeover began back in 2009. With the old analog signals, one could have a fuzzy screen—even no visuals at all—and still have audio. With the digital signal, the broadcast becomes choppy, and before long it goes completely black and silent. You have either a near-perfect picture or you have nothing. I have heard more than one anecdote of people in tornado-struck areas who did not lose power until after the tornado hit, but who could not hear the warnings because their TV signal had gone out. I don’t know how many fatalities, if any, were caused by this, but it is a problem that, in my opinion, was severely underrated when the rush to DTV was taking place.

4. Dangerous amateur videography.
There are a lot of videos out there of this year’s tornadoes, and a great many of them were not taken by experienced storm chasers or always-running security cameras. They are also not all taken by people who were a safe distance away from the tornado. One tornado video from Alabama was shot by someone who had a car accident while taking the video! This is a major problem. There is not one thing that can legally be done to stop people from taking video of approaching tornadoes if that is what they want to do, but it is a sad reflection on our society. I don’t blame storm chasers for this. Responsible storm chasers and weather spotters have provided a lot of on-site reports, helping newscasters and people following the situation online know when there is actually a confirmed tornado. Real-time reports of a tornado on the ground helped me decide to evacuate in advance of an EF-5 tornado. Some storm chasers behave highly irresponsibly on the road, and they should be condemned by the rest of the community for it, but overall these people take their hobby very seriously. The videos I speak of are taken by people who just happened to see the tornado and decided it would be a cool idea to get video of it, and the videographers clearly have no knowledge of how far away they should be or where to go if the tornado shifts its path. This particular trend is not the fault of storm chasers; it was produced by social media culture.

5. Lack of shelter from violent tornadoes.
The overwhelming majority of this year’s fatalities have occurred in violent tornadoes, those rated EF-4 and EF-5. This is because these tornadoes will utterly demolish well-built houses, leaving only a pile of debris over a foundation (EF-4) or a bare foundation altogether (EF-5). The Hackleburg, AL EF-5 tornado even buckled the concrete slab foundation of one structure, and the Neshoba County, MS EF-5 (“my” tornado) dug up dirt two feet deep. I think that the odds of survival in these tornadoes are still better than 50-50, but it is easy to see how this kind of situation is incredibly dangerous. The unfortunate fact is that a majority of houses in the South and Midwest do not have basements or storm cellars. My position is that storm cellars are preferable to basements, especially if they have a “fallout shelter” design in which the entrance is not directly above the main room, but is horizontally removed from it. I have read enough accounts of people who took shelter in their basements and were sucked out that (while I agree that basements are clearly preferable to any above-ground shelter) I cannot equate basements and storm cellars. I would also recommend firmly anchored handrails in the main room, in case the door was torn away. The opening sequence of Twister is not myth.

I definitely do not equate above-ground saferooms with underground shelter. These structures are engineered, yes, but they are highly vulnerable on two counts. One, if they are undermined from below, they will roll. Two, the engineering is based on a typical flying missile the size of a 2×4 and a typical flying missile speed of 100 mph. EF-5 tornadoes have wind speeds upwards of 200 mph and have even been clocked as high as 300 mph, though it is a matter of debate whether a large object would travel at these extreme speeds. However, these large objects do travel. In Smithville, MS, the town water tower was dented 120 feet above the ground by a car that became airborne. This is known for a fact by matching paint from the tower and the car. There is video on the Internet of a Canadian F5 tornado in which a whole house is clearly airborne at a great height before it disintegrates.

It’s easy to say, of course, that everyone should have an underground shelter. It is quite another to bring that about. I am opposed on principle to any government mandate to protect people from themselves if there is no risk to other people. This must be a matter of personal responsibility. However, I am in favor of rewarding the decision to install a storm shelter with a tax rebate or credit.  Such credits have been offered in the past, usually to specific regions after particularly high-profile and destructive weather events; I argue that they should be permanent and universal.

These are my suggestions about what should be looked into when the year 2011 becomes part of history, or when people begin to examine what has gone wrong with severe weather preparedness, whichever comes first. Undoubtedly other people will focus on other things. One thing is for certain: We need to know whether this year’s atrocious human toll was in any way preventable, because if it was, it must not be allowed to happen again.

Severe

Running from an EF-5: Part Three

I hope everyone had a good Mother’s Day, or just a good Sunday. This is Part Three of the series about the EF-5 tornado that went through central Mississippi on April 27, 2011. Part One and Part Two are linked.

Days later, after the terrible human toll becomes widely known, the scientific damage surveys come in.  I’d been keeping an eye on them, not really expecting this storm to be high on the priority list because there were fatalities in other areas such as Smithville (it is not known at the time that “my” storm was the same tornado that killed 3 women in Kemper County), but knowing that eventually it would be examined.  One day, the piece of news I have been interested in for personal reasons comes in; the tornado has been rated EF-4 with 180 mph winds.  It began around Philadelphia and lifted outside of Mashulaville.  The Jackson office of the Weather Service helpfully put a Google Earth file on their website that showed the tracks of the tornado and the supercell that spawned it; I download this file and look at it.  The mesocyclone—the strongly rotating column within the thunderstorm—did indeed pass directly over my house.  The tornado itself would have continued straight into downtown Macon if it had stayed on the ground, most likely missing my house, though barely.  This fits with what I heard the day it happened, but now I know just how bad it really could have been for the town.

Like, I suspect, a great many people in the South, I have graphic nightmares about the outbreak for several days.  When some comparatively mild thunderstorms come through a few days later, my nerves treacherously ignore what my meteorology-educated mind is saying, that there is nothing to worry about except lightning.  I dare not suggest that I have post-traumatic stress disorder when I did not actually experience a life-threatening trauma, or when so many who experienced the tornadoes directly undoubtedly do now suffer with this condition, but everything must have degrees, and I am clearly experiencing some degree of being traumatized.  It’s hard not to experience something like this when you leave home with the completely justified expectation that you won’t be coming back except to ruins, even when that turns out not to be the case.  In addition, there is the knowledge of what might have been, with a significant helping of meteorological education and a vivid reading-influenced imagination thrown in for good measure.  There is knowing that the tornado I had run from was every bit as bad as some of the worst beasts of the outbreak—except that it did not last long enough to make a direct hit on a closely populated site.

And then a week after the outbreak, the tornado’s rating is changed to EF-5, the highest on the scale.  This is the kind of tornado that leaves slab foundations swept clean, the kind that reduces every smallish building in its path to rubble, the kind that obliterates small towns.  In the case of this specific tornado, it’s the kind that, by the force of the wind and probably some microscale debris, pulls up blades of grass and digs out sections of the ground two feet deep.  I recall reading a comment by some meteorologist, I have no idea whom, to the effect that he would not believe an F6 tornado could exist (this was in the days when the old Fujita Scale was used) until he saw coffins pulled out of the ground.  Well, there is no such thing as an EF-6, and “F6” was never put into practice because there were no official damage criteria for it, but four more feet and this one would have been capable of that one man’s stated standard.  And yet I think the Hackleburg/rural Alabama EF-5 was still more violent.  The damage survey for that one is responsible for one of my nightmares.

Three women in Kemper County, MS lost their lives in this tornado that I ran from.  They lived in a mobile home.  There were surely others in the South who tried to take shelter in these structures and did not survive.  Trailers are not safe!  Granted, little will stand up to an EF-4 or EF-5, but a trailer won’t even stand up to an EF-2.  And there are a lot more of those than the 4s and 5s.  The Weather Service guideline of leaving a trailer is spot-on.  And even a constructed house isn’t necessarily safe, though the type of tornado that would create uncertainty about survival in these structures is mercifully rare.  However, such tornadoes do happen.  They happened that day in April.  I wish that more people and communities in the South had storm shelters—and underground ones.  Above-ground concrete bunkers may be all well and good, but houses in the Hackleburg and Phil Campbell area had their concrete block foundations destroyed by the EF-5 that went through there.  Also, something capable of digging up dirt two feet deep is quite possibly capable of undermining a slab foundation by the same process and ripping it from the ground by an extreme wind-tunnel effect under the now hollow space.  (That would be beyond anything I have ever read about, but the possibility has been theorized, and this is how it would happen.)  Anyone who can afford it should build a storm cellar—and it bothers me that more people in this region cannot afford it.  There should be a tax credit for it.

I have never left the house before over a tornado warning, or even a suspected tornado.  This was a decision that I made based on the information that was available to me at the time:  my knowledge of the off-the-charts atmospheric parameters that supported violent tornado formation, my experience driving in supercells, the extremely threatening hooked radar signature, the probable debris ball that is usually seen only in intense tornadoes, the path that would have taken it almost directly over my house, and the report from chasers and spotters of a confirmed large tornado with damage and debris.  I decided that the probability of this being a tornado that my house could not stand up to was unacceptably high.  It turned out that the tornado that I fled from was an EF-5, which seemingly justifies the action, and yet I can’t endorse the choice I made as a general public rule.  It happened to be a good decision based on the fact that I had time and I knew what direction to drive, but in general it is a risky decision, and risky decisions should be made only if there is extensive knowledge to support them.  Blind, panicked “I have to get out of here and it doesn’t matter where I go” driving is not something we need.  Anyone who doubts this should take a good look at some of the damage pictures that involve vehicles.  As a matter of fact, extreme vehicular damage was one of the criteria that the Jackson NWS office used to upgrade “my” tornado to EF-5.

Smithville, MS.  Hackleburg, Phil Campbell, Rainsville, Oak Ridge, and so many other small towns in Alabama.  Tuscaloosa and Pleasant Grove, AL.  Ringgold, GA.  And almost, but for the grace of God, Macon, MS.  The nonchalance that at least some people seemingly had comes back to my mind.  I hope it was the exception.  I hope that, after seeing what happened to their neighbors in small towns just like Macon, they are reflecting on their own close call.  Do they know what a close call they had?  Do they realize just how out-of-the-ordinary the tornado that was barreling straight for them truly was?  Do they realize that, if the tornado had not lifted, there would probably be another small town on the dreadful list of “leveled by an EF-5 tornado”?  And yet, there are so many uncertainties.  Would the tornado have maintained that strength if it had stayed on the ground?  Sometimes they don’t.  Or would it possibly have strengthened even more, as the horrific rural Alabama EF-5 apparently did as it tracked north?  No one can know.  But we can make sure that, if something like this should happen again in our lifetimes, we have a plan of action.

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Running from an EF-5: Part Two

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This is Part Two of a series of three about my experience with the EF-5 tornado that went through four counties in Mississippi on April 27, 2011. Part One can be found here, and Part Three, an account of the aftermath, will be forthcoming.

Wednesday, April 27, 2011.

Bzzzzzzz! My cell phone is still in vibrate mode.  I’ve forgotten to turn the ringtone on.  I pull my eyes away from the TV and answer it.  It is my father, who is at work.  “Are you—”

“I know,” I say.  “I’m going to take cover.”

“I’ll call after it passes,” he says.  His voice is clearly nervous.  We hang up.

I take another look at the radar that the weatherman is talking about.  That sure looks like a debris ball, I think, as the menacing supercell enters southwestern Noxubee County.  Then bzzzzz! The phone buzzes again.  This time it is one of my sisters.

“Erin, do you know what’s going on?”  Of course.  I have been following it on the local news, which, unfortunately, is swamped at this point with several simultaneous tornadic supercells, and have just checked the Internet to see if anyone has reported a tornado with this one.  “Well, they are saying in the tornado warning that they’ve got a confirmed tornado—a big one.”

“Does that look like a debris ball on radar to you?”  She says that it does.  “All right,” I say, arriving at a decision instantly, as the crawl-space foundation of this old house flashes before my mind’s eye.  “I’m getting the cat and getting out of here.”  She agrees.

The tornado safety guidelines put out by the National Weather Service do not endorse leaving a house in a vehicle.  I understand why.  In general, a house can be regarded as a comparatively safe place to be in a tornado, whereas a vehicle cannot.  Moreover, it’s possible to get on the road and drive directly into a different tornado or an area of high winds.  When I tell my sister that I’m planning to leave, I know full well that I am going against this advice, and for all these reasons, I don’t recommend that to people in general—certainly not when there is not even a confirmed tornado, and in most cases, not even when there is one.  However, as a meteorology student, I have closely monitored the extreme atmospheric conditions that would be in play for this event.  I am aware that, under these circumstances, tornadoes that form are far more likely than normal to become “violent”—to reach an intensity at which even well-constructed homes are definitely not safe to be in because every wall in them is blown down.  I am aware of what to expect if I choose to drive through the precipitating part of a supercell.  (I was close to the wall cloud of one a week ago, after all!)  I am aware that there is a clear spot north of Noxubee County, and there is nothing that will enter that area in the immediate future.  And, most importantly, I have enough time to get away.

But only just enough.  There is no time to lose.  The storm is moving quickly, and at the angle it’s coming, it will be upon me in 20 minutes.  I grab my laptop, leaving behind even the power cords.  I reflect for a moment on the irony of this; I had recently seen my first AC adapter go out and had to get this one over the Internet.  Well, there is no time to waste by crawling under my desk and unplugging the cord.  I grab my purse.  I shove my protesting cat into the cat carrier.  Carrying only these things, I run into the vehicle, hoping that the lightly falling rain does not penetrate the laptop case, and apparently (so I discover later) leave a rut in the yard in my rush to get out of there.  I head north.

I would not leave my cat at home, but the delay in grabbing up these things has cost me a few more minutes.  Meanwhile, the tornado has not waited.  It’s best not to say what speed I am driving, but no one else heading north is driving any differently.  I wonder how many of them are on the road for the same reason that I am.  The rain slacks off.  I never run into any hail on this trip.

It is between Macon and Brooksville that I start seeing small pieces of branches fall from the sky.  They are not large enough to slam to Earth with violence, so there is something almost graceful in it.  I’ve never seen anything like this before.  These are not being blown about horizontally by winds; they are falling like soft rain from the storm itself.  The movement is vertical.  The branches have been sucked into the mesocyclone, which tilts southwest to northeast; the part of the storm that I am under is nowhere close to the tornado!  Seeing debris brings everything to mind that I have pushed out in my single-minded focus on getting away.  It occurs to me that people somewhere may see debris from my house later on.  Well, I’m safe, and the cat is safe, I think to myself.  There’s nothing more I can do.

Almost mockingly, the sunlight breaks out as I leave Noxubee County.  I hear the buzzing of my phone once more.  It is my father, who has tried to call me several times since my sister called him and told him that I had decided to leave the house.

“You’re fine in that part of Lowndes County,” my father tells me over the phone.  That fits with what I had seen on the radar; I knew that there was a dangerous supercell in Monroe County (the Smithville tornado, it turned out).  I also know that, though nothing tornadic is coming for Starkville and Columbus at the time, I do not want to be stuck in one of these cities if that changed in an hour or so, as it often does during tornado outbreaks.  I also don’t like the idea of pulling off the road indefinitely.  I decide to stop at the house of friends in rural Lowndes County, and there I stay for an hour or so.

I am fully expecting that I will not have a house to go back to, or my house will be damaged beyond repair, or the town will be destroyed.  I’ve read a lot of personal accounts of extreme weather events, and now it seems that I am about to live that awful aftermath.  It is truly amazing how we are able to push thoughts like this out of our minds when we are focused on something critical, such as (possibly) survival itself.  Now that this is not an imminent concern, the ugly realities of a tornadic strike hit me.  I don’t know exactly what will be damaged, or how much, but there is absolutely nothing I can do about it.  All I can do is wait to hear some news.  It is a hideous wait, and yet, I am focusing more on the animal confined in her carrier next to me, and the fact that no one else was at home, than on the home itself.  No one wants to lose a house, but when all is said and done, it’s just a house.

Over the course of my visit, my hosts learn that Macon has not been hit.  The storm apparently passed over with rotation still apparent, but no tornado anymore.  To my astonishment, there was apparently some nonchalance about the whole event in at least some parts of Macon.  Finally I decide to return home, since I still indeed have one.  I get there in time to settle in and watch with amazed horror as live footage of the tornado in Tuscaloosa airs.  Later, I see video of the Noxubee County tornado.  I find out through the TV news and Twitter—Macon, amazingly, has power—that many people in the Southeast are not so fortunate as I have been this afternoon.  My own experience is pushed back to a different corner of my mind as the hideous extent of the destruction and suffering becomes known.  I have not suffered loss.  I focus on those who have.

Forecasting, Mid-latitude cyclones, Severe

Dangerous Severe Weather Situation for Tennessee Valley

So far the severe weather outbreak of late April 2011 has brought devastation to many different areas in the southern Plains and Southeast. A tornado that was probably of a violent intensity hit a small town in Arkansas last night, reportedly removing pavement from the ground, and tornadoes have touched down from Texas through Arkansas and Louisiana into Mississippi, Tennessee, and Kentucky today. The severe weather is going to continue through Wednesday as the second of two low pressure centers intensifies over the mid-South.

A powerful mid-level jet has formed, with winds screaming at 70 knots or more:


Winds and pressure at 700 mb

This will provide powerful upward forcing. Additionally, strong thermal advection feeding into the developing low pressure center (which has become quite strong today, checking in at 989 mb as of this writing) will promote instability as well as additional vertical uplift:


Temperature and wind at 850 mb

For specific tornado threat regions, the NAM model has been fixing on an area centered over the Tennessee Valley. Yesterday the bull’s eye appeared to be right over the state of Tennessee, but today, it has shifted somewhat south.

The 18 UTC run of the NAM had CAPE over 4000 J/kg in central Mississippi at peak (mid-afternoon Wednesday), with a local maximum roughly over the Golden Triangle region and Tupelo, MS:

This run also had 3 km energy helicity values literally off the charts over the same area:

The 00 UTC run has CAPE peaking around the same value as before.

It has, however, moved, the helicity indices to extreme northwest Alabama:

Bottom line? I think that at this stage, such deviations are just model noise. Observations will be needed to determine exactly what area will have the highest risk of severe weather tomorrow. However, it is important to note that the model has been very consistent with an elevated tornado threat Wednesday afternoon in the Tennessee Valley area. With that in mind, I offer up my own subjective severe weather threat map for this event. I am not assigning probabilities to any of the color regions of this map; they are present only to indicate the areas that I think are in increasingly higher danger of seeing powerful severe weather, including long-tracked tornadoes.

Forecasting, Mid-latitude cyclones, Severe

Another Multi-Day Tornado Outbreak Expected

The year is off to a record start in tornadic activity, and more is on the way. Another three-day tornado outbreak is currently underway, with day 1 having brought close to 40 tornado reports and over 250 hail and wind reports.

The system is expected to bring more severe weather to the eastern part of the U.S. through Tuesday and Wednesday. At the time of this writing, a squall line has developed in the Mississippi River Delta that is expected to push east overnight, bringing strong winds, rain, lightning, and the risk of embedded tornadoes.

This scenario is more complicated than the setup for the last big outbreak, which had a single powerful system to generate the intense weather. A closed low located over Arkansas is responsible for the day 1 activity. This low formed today from a shortwave kink in an upper trough. This low is expected to be blocked by a strong high pressure system off the Atlantic coast, causing it to move north and eventually northeast to die out over the Great Lakes area. However, a second shortwave kink is expected to enter the mid-South and undergo cyclogenesis on Tuesday afternoon or evening.


Surface low at 36 hours

The combination of the current cyclone’s development, the upper-atmospheric jet that is causing all this shortwave activity (see below), and the next cyclone’s appearance on the scene will result in there being significant sources of uplift.


250 mb jet stream


700 mb upward vertical velocities

The highest values of instability in the event are currently prognosticated by the models to occur around midday tomorrow. The NAM and GFS generally agree on the areas of high CAPE, with each model forecasting at least 3000 J/kg (and it should be noted that models do not do well with CAPE and have a tendency to underforecast. Keep an eye on observations such as soundings).


Surface-based CAPE at 18 hours, NAM


Surface-based CAPE at 18 hours, GFS

For Wednesday’s event, the highest CAPE values are expected to be over Mississippi. The NAM and GFS agree on the maximum values but have the location and orientation of the high CAPE axis different.


Surface-based CAPE at 45 hours, NAM


Surface-based CAPE at 45 hours, GFS

The Energy Helicity Index (EHI) values for 18 hours and 45 hours (midday Tuesday and afternoon Wednesday) indicate the areas that the models forecast are most conducive for tornadic supercell development. Here is what the NAM indicates for the two times:


EHI at 18 hours, NAM


EHI at 45 hours, NAM

I am especially concerned about the middle part of Tennessee on Wednesday if that is accurate. Those EHI values are almost off the scale, and they coincide with an area of at least 3000 J/kg CAPE. That area has a history of tornadoes, and between the strong instability, powerful uplift, and helical pattern to the winds, I think it is quite likely that the Tennessee valley may be in the worst part of this outbreak.

The Storm Prediction Center has already put up a Moderate risk for Tuesday and Wednesday. It is thought highly likely that at least one, if not both, of these days will see that risk upgraded to High.

Forecasting, Mid-latitude cyclones, Severe

Tornado and Severe Weather Outbreak in OK/AR/MO Thursday

1 Comment

I am expecting a tornado and severe weather outbreak to occur tomorrow in what I would call the heart of Tornado Alley.

However, that’s a worthless statement from any perspective—forecasting, meteorological, geographical—without a qualification of the term “Tornado Alley.” I have long thought that the true “heart” of Tornado Alley is not over Oklahoma City at all, but is instead farther east. In truth, where that heart is depends on what one chooses to look at. (For long-tracked violent tornadoes, the bull’s eye is, beyond a shadow of a doubt, over Mississippi.) Some meteorologists developed the idea of three distinct tornado alleys: Plains Alley, the traditional storm-chasing zone in the Plains states that is often referred to with the general appellative of “Tornado Alley”; Dixie Alley, a broad region encompassing much of the Southeast but not including parts of Texas that are climatologically and geologically more similar to Plains Alley; and Hoosier Alley, which is essentially the Midwest. However, if you really take a good look at it, I think you’ll find that the entire eastern region of the country between the two mountain ranges is Tornado Alley. There is no distinct border where you can say, “There are not nearly as many tornadoes in this small region as there are in either ‘Alley’ on each side of it,” and in the absence of such a thing, the only reasonable thing to do is to say it’s all one Alley. (Besides, “Hoosier Alley”? Really?) With the whole of the U.S. between the mountain ranges as Tornado Alley, it seems reasonable to expect the core somewhere east of Oklahoma City, and the meteorological data bear this fact out.

Now that that’s out of the way, let’s take a look at the science behind this and see why there will be severe weather, as well as where it should occur.

The weather-maker will be a low pressure center forming east of the Rocky Mountains. A low that is currently analyzed at 1009 mb (which is to say, not much of a low) is located over Kansas right now. This cyclone is forecast by the NAM to open up as it weakens and become more of a broad trough. This should be occurring right now, in fact. After that low dies out, a strong upper-level low (700 mb) is set to close off its circulation over the TX/OK panhandles on Thursday. Upper-level cyclogenesis should have occurred by 9:00 to 10:00 tomorrow morning (CDT). The usual vertical tilt of these kinds of cyclones will result in the surface low being over central Oklahoma at this time, and it should be at about 1000 mb by midday tomorrow.

Thermal advections will be strong, with the greatest warm-air advection (WAA) occurring in an area just west of Tulsa, OK to north TX to the AR/LA border. Temperature advection drops off in northeast Arkansas.

Surface dewpoint temperatures will be quite high, approaching 65-70 from Tulsa south along the OK/AR border in a narrow swath. A larger area of 60-65 F dewpoints will cover the area from Oklahoma City through a diagonal line bisecting Arkansas NW-SE.

However, despite all this moisture around the surface, a dry socket should be present at the critical 700 mb level in the atmosphere. This shows up on a synoptic model forecast map as a medium brownish-gray blotch of low relative humidity.

All this will lead to mixed-layer CAPE values approaching 2500 J/kg.

The instability will definitely be present, and between the thermal advection and the diffluence-based forcing from the low, lift should be present over the target area. Decent upward vertical velocities are forecast by the models to be present over the area of interest.

A cap of CIN will be in place early in the day, but as the surface heats up, the surface temperature should remove the temperature inversion, making it easier for moist parcels of air to rise.

The disappearance of the capping inversion also shows up in forecast soundings for the area bounded by Tulsa, Fort Smith, and Fayetteville. They indicate that a substantial warm surface layer will have developed by late afternoon, and with CAPE values as high as they are expected to be, this will set off convective growth.

Helicity values are also supposed to be quite high, with 0-3 km at 300-500 over the target area, at a time coinciding with the high CAPE values and the eroded cap, which will support supercellular development instead of linear. This increases the risk of tornadoes and large hail.

The Storm Prediction Center has already put up a Moderate risk for this general area, which I agree with 100%. I wouldn’t be overly surprised to see them go with a High by tomorrow morning, though this is a small enough area that they may not do it on the basis of its size. In any case, I am growing quite confident of a risk of supercells tomorrow for eastern Oklahoma, western Arkansas, and southwest Missouri. If I were to pick one city that I think has the highest chance of a significant impact, I’d go with Tulsa. However, a slight shift in any direction of the low’s movement would result in a shifting of the severe weather risk, and these events are never points, but areas. It is looking like a potentially dangerous day tomorrow for this region of the country, so people living there should make sure they keep aware of what is going on in the afternoon and be ready to act.

Severe

Severe Weather Season Starts Off With a Bang

Having lived in the Southeast for most of my life, I find it a bit dishonest to say that there is a defined “severe weather season” for this region. We, after all, are the ones who rang in the new year with a tornado outbreak. We’ve had tornadoes a couple days before Christmas, in January, during hurricanes, and occasionally even during the summer months. We have certainly had powerful thunderstorms in the summer months that have brought extreme wind, hail, and lightning. However, it is fair to say that there are periods of the year when the most destructive types of severe weather are more common than others, and perhaps these are what should be defined as the “severe weather seasons” for the South. If this is the case, then we are entering the spring severe weather season. We’ve already had a taste of it when the powerful squall line came through last week on Thursday and Friday, generating several tornadoes and 100-mile-an-hour winds in Tennessee. That, however, was just a teaser, and an event is currently in the process of unfolding that promises to be more significant. Tonight’s event has a couple of parameters in place that last week’s did not, at least not to a great extent, plus all the parameters that last week’s event did have. I am using images from the RUC model, which is a short-range model containing live observations that is run every hour.

First of all, there is a strong jet over the region.

This jet will have uplift occurring on its northeast side. Since it is a 120-knot jet, this will provide significant uplift.

Secondly, there is a decent thermal gradient and fairly strong winds at the 850 mb level.

This will provide fuel to the strengthening low pressure center that is the source of the upcoming bad weather. The advection of warm air is also a source of uplift.

There is also an area of vorticity (essentially, rotational motion of wind). Vorticity is not the source of tornadoes, despite the suggestive name; in fact, uplift associated with vorticity is not directly under the strongest area, but is instead downstream of it. The vorticity is being advected in that direction by the motion of the air.

Incidentally, that accounts for three parameters providing favorable severe weather conditions over pretty much the same spot: Memphis/St. Louis/NE Arkansas.

Now, the parameters that last week’s event did not have in place relate specifically to supercell formation. Last week’s event had plenty of uplift and wind shear, just not a lot of atmospheric instability and helicity. Tonight’s expected outbreak is a different story.

Here’s atmospheric instability, as measured by CAPE (convective available potential energy):

There are values approaching 2000 J/kg expected over, yes, the same area where a lot of uplift is supposed to be occurring. This isn’t a stupendous value, but it’s pretty significant for an early-season outbreak. Some of the highest values of CAPE I’ve ever heard of were on the order of 6000 J/kg for events that produced F5 tornadoes. Where other favorable parameters exist, CAPE is directly correlated with the formation of thunderstorms.

Here’s helicity.

The peak swath of high helicity is a little off-center compared to the rest of the favorable parameters, but a pretty significant area of it is nonetheless centered right over the area in the lower Midwest/upper South where the rest of the favorable parameters are converging.

I am expecting a tornado outbreak over this area tonight, pushing eastward into Tennessee in the early morning hours. This is not good, as nighttime tornadoes are easily the deadliest of all. (See my previous blog entry about the tornado outbreak of February 5, 2008 for more about Southern tornadoes.) I completely agree with the Storm Prediction Center’s decision to issue a moderate risk for this region tonight and tomorrow. I think it is possible that tornadoes may occur a bit farther south than currently indicated, mainly because of that high helicity index, but I am not expecting there to be a very great threat much south of Highway 82.

Mid-latitude cyclones, Severe

Epic Storm to Bring Severe Weather to the South

Any “weather weenie” is well aware of the fact that a major storm is coming for the eastern United States (yes, it really is that big). Accuweather.com and the Weather Channel are beginning the hype, Twitter is abuzz with forecasts and speculation (at least in the weather-weenie corner of it), and even the stolid National Weather Service has gotten in on this, with the Storm Prediction Center calling for “Particularly Dangerous Situation” winter storm warnings. (A PDS ordinarily is issued for severe weather—typically, in fact, for the type of severe weather event that has a historic tendency to generate violent tornadoes.) Indeed, blizzard conditions will be widespread across the Midwest, probably affecting an area as large as the “Storm of the Century” of March 1993. The culprits are a low pressure center and a mass of arctic air coming from Canada. The unseasonably warm air that we have enjoyed in the Southeast is going to fuel the system, so to speak.

I am not going to touch on the snow and ice aspects of this. The area that will undergo winter storm or even blizzard conditions is simply too large for me to give anything other than a large-scale overview, for one. And two, this is primarily a Southeastern blog as far as actual forecasts are concerned, and we in the South are going to have to deal with the system in a different way: severe thunderstorms. That warm Gulf air that will feed the system is going to be generating what’s known as a “warm sector.”

Mid-latitude cyclones such as this one have three distinct sectors: one to the east of the cold front, one to the west, and one that remains to the north. The north sector is what will be producing the snow and ice; north sides of cyclones typically have a constant flow of precipitation, because the cold front associated with the low does not actually pass over these regions. The west side is the “dry” side, in general (though there are exceptions); this is also typically a cold part of the system. That’s what’s going to bring a return to winter temperatures for the South; it will follow the passage of the cold front. And the warm sector is the southeastern side—the side that will have southerly flow from the Gulf of Mexico. These 60s and 70s that we’ve been experiencing, in other words.

There will be several factors that will create severe weather for us. I am going to illustrate these with images from the North American Mesoscale (NAM) model, downloaded from TwisterData.com. First is the location and intensity of the jet stream:

That image shows that the jet at 300 mb (~9000 m) will have 140-knot winds over ArkLaTex on Tuesday evening. The jet typically does have strong winds on the order of 80 knots, which is why it is a death sentence (via shear) for hurricanes in the summer, but these same winds that rip warm-core tropical cyclones to shreds create conditions that enhance cold-core cyclones in the cool season, when the jet is much farther south. 140 is quite strong even for winter. Furthermore, the location of the jet indicates that air will be drawn to the northwest along the eastern end of the strongest points—the exit region, in meteorological parlance. The image doesn’t appear to depict this, but the southeastern flow I am referring to is taking place vertically, and this image only shows winds at the 300 mb level. This will create areas of divergence in Mississippi, Louisiana, and eastern Arkansas. Divergence leads to a “vacuum” of sorts—an area of lower pressure—and therefore to rising air.

The second factor is the extreme temperature gradient.

Again, take a good look at Arkansas. This is an image from the same time as the one depicting the jet stream, but much lower in the atmosphere (850 mb, or 1500 m). The 850-mb low is located around Fayetteville, and you can see the wind flow around it. But look at the colors, which represent temperature. That is a very strong cold front, and the reason for it is the extremely unseasonable warm weather across the Gulf states. You can see the southerly flow of warm, moist air, creating the warm sector. The wind flow will be moving warmer air into areas of cooler air (the wind barbs are crossing isotherms), a process called warm-air advection. Look at the strength of the winds at this level, too. There are 65-knot winds forecast at 850 mb! This is hurricane-force.

Finally, the pressure gradient itself:

I will direct your attention to the isobars over the Plains. The low hasn’t even fully intensified yet, but already there is a 40 mb gradient because the high is so darn strong. It is this pressure gradient that will be generating the intense winds with this system, producing blizzard conditions north of the freezing line, and severe weather south of it.

Now, the $64,000 question: What type of severe weather are we talking about? None of the above sounds like particularly good news, but fortunately (for north MS, at any rate), I do have some comparatively good news now. I do not think our tornado risk is going to be all that high, nor our large hail risk. Instead—you guessed it—I think we are in line for some very strong winds as the cold front approaches us late Tuesday night/early Wednesday morning, combined with a lot of rain and the chance of small hail. There will be some instability, but CAPE levels are not going to be much higher than about 750 J/kg across Mississippi. The helicity index, a parameter reasonably predictive of supercell formation, is not expected to be very high. I think there is a chance of supercells in south MS (let’s say south of I-20), but at the present time I am not seeing this type of severe weather event on a large scale.

However, as people in north MS can certainly attest after the repeat punches of severe weather over the past year, high winds can be damaging enough on their own, and this system has the potential to generate some very strong winds for us. All in all, though, I think we are dodging not one, but several bullets with it.