http://www.nws.noaa.gov/om/assessments/pdfs/historic_tornadoes.pdf
I am particularly interested in findings 9 and 10 on pages 18-19 (26-27 of the PDF) regarding the content of the text messages in tornado warnings:
It seems to me that the usage of "tornado emergency" has gotten out of hand, as no one person or office can seem to agree on when and how to use the term. I used to support its use, but I now think the term should be replaced since I don't think the phrase "tornado emergency" really helps anyone, especially given how it is supposed to be used according to NWS Directive 10-511:
However, like I said, I think the phrase "tornado emergency" should instead be replaced by very strong wording in the warning. I think some of the issues with getting people to heed warnings is how they sound to someone hearing them. I realize almost any governmental organization is going to be more conservative so as to avoid causing panic and what not, but in situations like this where the environment is dangerous and damaging/deadly tornadoes have already been spotted or can be seen on TV or chaser streams, saying
"this is a life threatening situation"
at the bottom of the warning text isn't good enough. First of all, the NWS warning system is antiquated and needs an overhaul. Second, for situations like this, the wording needs to be more like
"if you aren't in a secure shelter, such as an underground storm cellar, you are not likely to survive a direct impact from this tornado"
or, even more extreme,
"this tornado will kill you if you do not take adequate shelter"
would probably get peoples' attention better and cause more to heed the warning (so long as its use is not abused...unless the warning overhaul includes that mention in a standard tornado warning). I don't think the excessive loss of life was entirely due to NWS warning policies, however. There certainly was a unique and unfortunate confluence of failures/difficulties that contributed to the death toll (i.e., NWR going out, KHTX going down etc.).
Switching gears: As far as SPC is concerned, I think high-end situations like this call for adjustments to the probabilities associated with convective outlooks. For example, the 2000 UTC SWODY1 had only a small area of 45% probability for tornadoes. Looking at the observed reflectivity at around the time that convective outlook was issued, and given the volatile environment, I don't think a >45% probability for tornadoes, with only a slight amount of area added outside that region of 30%-45%, really gives a true sense of the likelihood of tornadoes in that area, especially given that the most lethal tornado was within 30 minutes of touching down by the time the outlook was issued. I understand that part of those probabilities includes forecaster certainty, but I don't see how a(the) forecaster issuing that outlook can only see the chance being "greater than 45%". That may be true, but I think the probability was way over 45%. Hell, it should've been nearly 100% for tornadoes. I don't see why a 60% or 75% or even a 90% contour can't be added in situations like this. While it may be true that areas within the 45% contour technically have a greater than 45% chance of seeing a tornado nearby, I think that undercuts the true potential. Most people aren't going to see that and think "well, it's only a 45% chance...".
Anyway, I'd love to see some discussion sparked about this (and other findings/issues brought up in the service assessment).
I am particularly interested in findings 9 and 10 on pages 18-19 (26-27 of the PDF) regarding the content of the text messages in tornado warnings:
NWS Service Assessment said:Finding 9: Forecasters had differing interpretations of the instructions in NWS Directive 10-511
concerning “Tornado Emergency.” This inconsistency caused confusion among those media
partners whose market areas were covered by multiple WFOs.
Recommendation 9: NWS regional headquarters should ensure that WFOs in their areas of
responsibility consistently apply instructions for the application and use of “Tornado
Emergency.” NWS regional headquarters should inform OCWWS of any requirements to clarify
or provide more detail on the use of “Tornado Emergency” in NWS Directive 10-511.
-WFOs BMX and FFC used the wording “Doppler radar indicated” for the basis of their
warnings and statements; however, staff were aware that large destructive tornadoes were on the
ground based on spotter reports, debris ball signatures on radar, or through visual confirmation
via television (see Figure 8). The assessment team echoes the findings of the Super Tuesday
Tornado Outbreak of February 5-6, 2008, Service Assessment: Usage of generic wording may
lead people in the warned area to feel the threat is not as great as it actually is.
Finding 10: Several WFOs used the generic “Doppler radar indicated” wording in their tornado
warnings despite evidence of a tornado in progress.
Recommendation 10: When WFOs have ground truth reports, they should refer to them in
severe weather products, rather than “Doppler radar indicated.” OCWWS and the regions should
review NWS Directive 10-511 and ensure the directive supports this recommendation.
It seems to me that the usage of "tornado emergency" has gotten out of hand, as no one person or office can seem to agree on when and how to use the term. I used to support its use, but I now think the term should be replaced since I don't think the phrase "tornado emergency" really helps anyone, especially given how it is supposed to be used according to NWS Directive 10-511:
The THIRD bullet??? I think if the wording was that important it should be the first bullet. IF the NWS were to continue going down this road, then instead of issuing a tornado warning and calling it a tornado emergency (which, of course, does not confuse anybody[/sarcasm]), NWS meteorologists should issue a tornado emergency, a strictly different product than a tornado warning.NWS Directive 10-511 said:In exceedingly rare situations, when a severe threat to human life and catastrophic damage from a tornado is imminent or ongoing, the forecaster may use the terminology "TORNADO EMERGENCY FOR [GEOGRAPHIC AREA]" in the third bullet of the warning. Additionally, in such a situation, this terminology should only be used when reliable sources confirm a tornado, or there is clear radar evidence of the existence of a damaging tornado such as the observation of debris.
However, like I said, I think the phrase "tornado emergency" should instead be replaced by very strong wording in the warning. I think some of the issues with getting people to heed warnings is how they sound to someone hearing them. I realize almost any governmental organization is going to be more conservative so as to avoid causing panic and what not, but in situations like this where the environment is dangerous and damaging/deadly tornadoes have already been spotted or can be seen on TV or chaser streams, saying
"this is a life threatening situation"
at the bottom of the warning text isn't good enough. First of all, the NWS warning system is antiquated and needs an overhaul. Second, for situations like this, the wording needs to be more like
"if you aren't in a secure shelter, such as an underground storm cellar, you are not likely to survive a direct impact from this tornado"
or, even more extreme,
"this tornado will kill you if you do not take adequate shelter"
would probably get peoples' attention better and cause more to heed the warning (so long as its use is not abused...unless the warning overhaul includes that mention in a standard tornado warning). I don't think the excessive loss of life was entirely due to NWS warning policies, however. There certainly was a unique and unfortunate confluence of failures/difficulties that contributed to the death toll (i.e., NWR going out, KHTX going down etc.).
Switching gears: As far as SPC is concerned, I think high-end situations like this call for adjustments to the probabilities associated with convective outlooks. For example, the 2000 UTC SWODY1 had only a small area of 45% probability for tornadoes. Looking at the observed reflectivity at around the time that convective outlook was issued, and given the volatile environment, I don't think a >45% probability for tornadoes, with only a slight amount of area added outside that region of 30%-45%, really gives a true sense of the likelihood of tornadoes in that area, especially given that the most lethal tornado was within 30 minutes of touching down by the time the outlook was issued. I understand that part of those probabilities includes forecaster certainty, but I don't see how a(the) forecaster issuing that outlook can only see the chance being "greater than 45%". That may be true, but I think the probability was way over 45%. Hell, it should've been nearly 100% for tornadoes. I don't see why a 60% or 75% or even a 90% contour can't be added in situations like this. While it may be true that areas within the 45% contour technically have a greater than 45% chance of seeing a tornado nearby, I think that undercuts the true potential. Most people aren't going to see that and think "well, it's only a 45% chance...".
Anyway, I'd love to see some discussion sparked about this (and other findings/issues brought up in the service assessment).
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