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CASA A System to Speed Up Forecasting Tornadoes


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William F. Bunting, the meteorologist in charge of the National Weather Service’s forecast office in Fort Worth, was skeptical that CASA would improve tornado warning lead times, but he said that its improved rainfall estimation would help predict flash floods, theleading cause of weather-related deaths in the United States.

Interesting thing to say. They scan with faster updates and closer to the ground, so sudden spin-ups should lead to increase warnings in some situations. Maybe they think that's not gonna happen all that often or are just tempering expectations. Can any NWS mets comment on the general attitude that WFO's have toward possible implementation of CASA? Maybe data overload?

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I'm on the skeptical side that this would help reduce tornado injuries and death. Honestly, I don't believe increasing warning lead time from what it is on average now (15 min) would help much. I don't see an extra few minutes helping, as the majority of tornado deaths occur from people who don't head warnings or don't have adequate shelter to begin with...or tornadoes that are just so strong, it doesn't matter where you hide.

As for protecting from localized, brief spin-ups...well, since these tornadoes are so brief, the warning time would only be a few minutes...

The way I see it, there are only two ways we can reduce the dangers or tornadoes

A ) Make tornado warning 100% accurate (no false alarms) and narrow the area that is warned, so more people take shelter in warnings

B ) Find a way to prevent tornadoes or stop them in their paths

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I'm on the skeptical side that this would help reduce tornado injuries and death. Honestly, I don't believe increasing warning lead time from what it is on average now (15 min) would help much. I don't see an extra few minutes helping, as the majority of tornado deaths occur from people who don't head warnings or don't have adequate shelter to begin with...or tornadoes that are just so strong, it doesn't matter where you hide.

As for protecting from localized, brief spin-ups...well, since these tornadoes are so brief, the warning time would only be a few minutes...

The way I see it, there are only two ways we can reduce the dangers or tornadoes

A ) Make tornado warning 100% accurate (no false alarms) and narrow the area that is warned, so more people take shelter in warnings

B ) Find a way to prevent tornadoes or stop them in their paths

I do agree with you on some aspects. I don't see an extra few minutes helping in terms of tornado deaths, because I think a majority of the deaths occur where the people don't heed the warnings, or don't have good shelter to go to. If CASA does have faster scans and can scan closer to the ground, then it would satisfy part A, where there would be less false alarms. Faster scans and closer scans to the ground would also help in situations with fast moving tornadoes.

Having less false alarms might go hand in hand with more people taking warnings more seriously, and therefore taking shelter. It might get rid of the "it won't happen to us, so I won't take shelter" mentality.

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I think you guys are forgetting that we're talking about average lead times; when that increases that means you're likely decreasing the number of negative lead times and increasing the number of positive lead times., we're not just talking about going from 12 to 15 minutes.

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I'm not sure who they'd get to maintain such a network. The way it stands now...Dual Pol has been pushed back yet another year. Implementing a network like CASA would cost 100s of millions not to mention the training and maintenance required.

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First of all, full disclosure. I have been a part of the CASA project since 2004, developing and integrating software, directing radar operations, and maintaining the hardware.

One thing I've learned is that the human factors side of things, how people receive, interpret, and react to weather information, is tremendously important, and can render scientific data mute should it not be considered appropriately. I know for a fact that when I have been on the plains and had tornado warnings nearby, I am the first one out there looking for it. For the general population this is textbook wrong behavior. But it's human nature that when a marvel of nature, a true demonstration of power, is nearby, you are drawn to it. It could be that where I live we just don't see these things, so the novelty aspect is still there, but judging by the number of storm chasers I see in Oklahoma, it probably never gets old.

Irregular behavior WRT to weather information is not only limited to the general public. I've had EMs tell me, even if they have advance warning of an incoming tornado, they refrain from blowing a siren until the last minute, because they want the public's response to be, "take cover immediately", not "well maybe I have some time, let me go home, or flee, etc." Other EMs will blow the siren as soon as they have information that they might be in the crosshairs. For these very strong tornadoes, fleeing might be your best chance at survival, whereas for weaker ones, exposing yourself outside is probably much more dangerous. It goes to show the need for agility in response and warning. CASA, with our concentration on the low levels of the atmosphere, dense coverage to mitigate the earth curvature problem, and network concept allowing realtime multi-doppler winds, could reduce false alarms and increase lead time slightly, but we are also putting a lot of time and effort into communicating information over multiple forms of media, and working closely with EMs who direct first responders.

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I'm not sure who they'd get to maintain such a network. The way it stands now...Dual Pol has been pushed back another year. Implementing a network like CASA would cost 100s of millions not to mention the training and maintenance required.

It's a fair point. Nexrad cost billions. I am doing my best to automate as much of the operations as possible, harden the system to reduce mean time between failures, and find places to reduce costs, but it will take a serious commitment from the govt. and/or industries who would benefit in order to deploy over a wide area. Training is non-negligible too, as is finding qualified staff.

At the moment we operate 5 radars, 4 in southwest Oklahoma and a single one in Massachusetts that I often post images from.

In the next year our plan is to take some of our remaining funding and migrate the network to the Dallas Fort Worth metro area in an effort to demonstrate value. We'll also add 2 new radars. It's clear from this last tragic event just how much population density affects the outcome of severe wx and not to get all "weather channel it could happen tomorrow", but a major tornado in the DFW metro area would be a very big problem. We are currently working with EMs and public officials to help us in our new deployment, and so far so good. We also engage the NWS heavily, and currently have a feed of our data into the OUN forecast office, but we all know the state of federal govt. financing, and their timelines for adoption of new technology exceed our expected lifespan. In a large city with a lot of interests we hopefully can find enough co-sponsors to carry us for a while, but when talking about the nation, or sub-regions as a whole, we'll have to improve our system building skills in order to survive once our funding expires.

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Interesting thing to say. They scan with faster updates and closer to the ground, so sudden spin-ups should lead to increase warnings in some situations. Maybe they think that's not gonna happen all that often or are just tempering expectations. Can any NWS mets comment on the general attitude that WFO's have toward possible implementation of CASA? Maybe data overload?

That is definitely an issue that's not to be ignored. With lots of dual-pol radars, networked in a way that you get a lot of derived products in close to realtime, it overwhelms even those of us who know the system best. Since we've started ingesting the data into AWIPS in the FO, we've really taken a drill-down approach. Merged reflectivity and multi-doppler winds on a large scale. One low-level scan from each radar every minute is green-lighted on updates. The rest is basically on-demand only if a met really wants it and has time to look.

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I'm not sure who they'd get to maintain such a network. The way it stands now...Dual Pol has been pushed back yet another year. Implementing a network like CASA would cost 100s of millions not to mention the training and maintenance required.

Really? Oh dear.

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Really? Oh dear.

Yeah, it was supposed to start coming online in FY12...now it's calander year '13. Meanwhile, we've (GSP) completed tons of training that we'll forget by the time Dual Pol makes it here.

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