By KSN Chief Meteorologist Dave Freeman

November 2004 -- The National Weather Service has announced two important developments that will affect us all this coming severe weather season! The first is something that has been in development for quite a while, and the other is something that has been talked about for more than 50 years!

First, beginning in the spring of 2005, we will start to see severe weather warnings issued using areas defined by polygons instead of by county. This is a great change, because there are so many instances where storms are affecting part of a county while in other areas there is no threat of severe weather. Of course, the KSN WeatherLab has long had a practice of showing you which parts of counties will be affected by severe weather, using KSN High Definition Doppler Radar. Because High Definition Doppler Radar is the most powerful, most accurate and fastest private Doppler radar in Kansas, it is the perfect tool to really pinpoint where severe weather will strike. We have always been able to isolate the threat of severe weather to parts of counties--for example, saying a warning is in effect for Eastern Sedgwick County. But, now this change will begin to take effect behind the scenes. It is a great step, and all of us on the KSN WeatherLab Team salute the National Weather Service for this move!

More applause for the NWS is in order for a decision to conduct an important experiment this coming severe weather season in Kansas changing the way severe thunderstorms are defined. You may recall that I first wrote about this issue in August of 2002, calling on the National Weather Service to adjust the size of hail that prompts a severe thunderstorm warning. In that column, I shared the history of how "severe" hail came to be 3/4" (the size of a penny) back in the 1950s. I called on the NWS to go "back to the future," and use 1" (slightly larger than a quarter) instead. This is because penny sized hail by itself does not really pose any sort of special threat--there is no need to go to shelter, etc. But, with quarter sized hail, some property damage can occur and windows can be broken. This is a much more significant size of hail that really does warrant folks taking action at home.

Now, the National Weather Service offices in Kansas and in Hastings, NE, will conduct a field experiment this coming storm season using the 1" hail criteria for severe thunderstorm warnings. Here in the KSN WeatherLab, we believe this will reduce the number of severe thunderstorm warnings, and focus attention on those storms that really do pose a threat to the public. We will do all we can to support the Weather Service in this experiment, which we believe will be successful.

It is important to note that while the hail criteria for a warning will change, the wind speed for severe thunderstorms will remain the same. Winds of 58mph or greater are considered "severe." Here in the KSN WeatherLab we believe this is the right thing to do, as 58mph winds are strong enough to cause minor property damage, including breaking windows.

I salute the National Weather Service for both of these decisions, which show that the agency is really listening to its customers--you and me!

Dave Freeman
KSN Chief Meteorologist
weatherlab@ksn.com