GARRETT’S BLOG: Weather Service To Test Graphic Tornado Wording

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Technology has come a long way since 1988 when the WSR88D (Weather Surveillance Radar 1988 Doppler) radar network was installed. Doppler radar works by measuring the “doppler shift”. Moving objects have different wavelengths, think of a train passing you; it sounds higher pitch and louder as it nears and then sounds lower pitch as it leaves. Doppler measures moving objects in thunderstorms and we can see winds spinning in different directions. It changed the way tornadoes were forecast.

The WSR88D network has seen several upgrades. With NEXRAD (Next Generation Doppler Radar) math algorithms were worked into the radar which triggered alarms for meteorologists such as ‘Mesocyclones” or “Tornado Vortex Signatures” which alerted the meteorologist on duty that rotating winds could be occurring. While this undoubtedly saved hundreds of lives, it can also be argued that we’ve become too good at predicting rotating winds. The false alarm rate on Tornado Warnings is as high as 75-80%. Not all rotating storms produce tornadoes, but most strongly rotating storms receive Tornado Warnings. The high false alarm rate, in my opinion, can be blamed for the high number of tornado deaths in the last few years. A study at Mississippi State after last year’s Alabama Outbreak showed apathy towards the warnings. Most people do not seek shelter, in fact, most people go outside and then look to secondary information source. Quotes such as: “I didn’t think it would be that bad” or “I would rather just watch my TV show and die than listen to weather interruptions” came from residents in Smithville, MS which was leveled by an EF5 Tornado last April.

And now, Doppler Radar is getting yet another upgrade. Dual Polarization Doppler or “Dual-Pol”. Doppler Radar scans the horizon from the bottom up, but with Dual-Pol we’ll scan the horizontal and the vertical space of the atmosphere. The result will be greater detail in thunderstorms. For example, Dual-Pol can actually see the debris lofted by tornadoes allowing meteorologists to know a tornado is actually “on the ground” with damage occurring. It will also be able to do many other things such as show exactly where precipitation changes in winter time from rain, to sleet, to ice, & snow.

Starting April 2, 2012 the National Weather Service will be testing enhanced wording in the Springfield, MO and Wichita, KS areas. In the past, you may have seen: “Doppler radar indicates a developing tornado” or “Storm spotters reported a tornado”. The additional wording will be stronger to draw more attention to dangerous tornadoes. This gives the Weather Service a way to make the truly damaging tornadoes like Joplin stand out from tornadoes that occur in squall lines like the Crawford Co EF1 last month.

I attached the .pdf document below that I received. In a Reuters report today, interviews with meteorologists in the Springfield area said phrases such as : “MASS DEVASTATION IS LIKELY”, “THIS IS A CATASTROPHIC TORNADO”, “COMPLETE DESTRUCTION OF ENTIRE NEIGHBORHOOD IS LIKELY” could be used.

The document below also shows a somewhat tiered warning system with tornadoes being: Tornado Indicated, Tornado Observed, Tornado Significant, Tornado Catastrophic. And with the Dual-Pol radar we’re actually able to distinguish the different types of tornadoes and even see the damage as it’s occurring. The end result is makes warnings more accurate and hopefully saves more lives in the process.

Dual-Polarization Radar that will cover Northwest Arkansas and Fort Smith is scheduled to be installed in the Fall of 2012

Document: Tornado Warning Wording


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