There was a big debate on our Weatherbrains podcast two weeks ago about whether television stations should cover tornado warnings wall to wall. The debate was sparked by storms on Saturday, May 2nd and Sunday, May 3rd that produced several tornado warnings during network television sports events, including the Kentucky Derby and NBA Playoffs.
Local Birmingham sports talk show host Paul Finebaum took the television weather folks to task, saying that they had gone power crazy and were costing business millions of dollars in business when advertising schedules were pre-empted by the weather broadcasts.
The discussion evolved into a debate about whether there are too many tornado and severe thunderstorm warnings. There was also extensive discussion about whether the National Weather Service storm based warnings (SBW) were a good thing or a bad thing.
In the SBW program which began in 2007, National Weather Service meteorologists began issuing warnings are areas defined by polygons, rather than for entire counties. The goal of the storm based warnings is to reduce the total area affected by an individual warning. In the past, a tornadic supercell storm moving east northeast near Sumiton would have prompted a tornado warning that covered all of Walker County, all of Blount and all of Jefferson County, even though the potential tornado would only affect a small percentage of the land area of all those counties. The old warnings would have covered over 2,580 square miles. A polygon warning could be drawn that would only affect 250-300 square miles. The number of people affected by the warning would be reduced by an even bigger factor.
The challenge comes when two or more storms are affecting one county. You can have a situation when there could be two, three or even more warnings issued for a single county at the same time. As J.B. says, this can be very confusing for John Q. Public. Especially when you consider the fact that there are inconsistent policies for outdoor sirens and the fact that NOAA Weatheradio cannot parse out parts of counties for its tone alert system.
So it can be confusing to the general public about whether their location is in a warning or not. This will be taken care of in time as GPS based devices are developed. Reverse 911 systems are also being used and could be adapted to call only homes in the warning polygons.
So, there is no question that storm based warnings reduce the areal coverage of the alerts. But do they create confusion for you as the end user? Do you understand them? Do you know how to interpret the polygon warnings? Is the news media doing enough to clear the confusion during warning events? How can we do a better job in the National Weather Service/Emergency Management/Media partnership to communicate storm based warnings? Please share your ideas.
Tomorrow: are there too many warnings?
