In recent years, especially with the widespread use of social media and availability of information around the clock and at our fingertips, many more people have become familiar with these outlooks and the terms used. There has also been a call to update the outlooks to provide better delineation of the risk that the public faces from severe storms. In particular, "Slight Risk days" seem to cover a wide gamut of severe weather possibilities, from a small threat for a damaging wind gust or large hail to something just short of a tornado outbreak.
Responding to the call to better define the risk, take into consideration the research and advice of social scientists who specialize in communicating risk or threat to the general public, and to provide better consistency with other NWS products, SPC will use a new classification system for their severe weather outlooks starting October 22, 2014. The new system can be found in the tables below (pay particular attention to the first table). The probability of tornadoes, 1"+ hail, and/or 58+ mph wind in a particular area defines the risk outlook category issued by SPC. NOTE: There will be NO changes to the watches or warnings issued as a result of this modification.
The biggest change we will see will be the addition of two new risk areas - "Marginal" and "Enhanced." The Marginal Risk indicates that the chance of severe weather is very low but not non-existent (or marginal). The Marginal Risk would replace the current "See Text" areas in the outlooks. According to table above, areas under a marginal risk of severe weather have a low chance of severe storms - less than the slight risk of previous years. Enhanced Risk indicates a more significant chance of severe storms and it will be used for "high-end" slight risk areas. In other words, the current slight risk category will be split between "slight" and "enhanced." Enhanced risk indicates a higher chance of severe weather than slight risk, but not quite up to a moderate risk. There will be no changes to the moderate or high risk areas.
In addition, each Severe Weather Outlook text bulletin that accompanies the maps will contain a "public" section that describes the weather risks for that day in non-meteorological jargon, so that the general public can understand the threat. An example of a day which had a high risk of severe weather (May 24, 2011) is shown below, followed by what the outlook areas would look like under the new classification system (click each for a larger image).
|Example showing the classification system for severe weather outlooks as used on May 24, 2011|
|How the convective outlook would look for May 24, 2011 using the new classification system|
We'd love your feedback! Let us know how we can make the transition easier for you, as ultimately the decision to prepare and take action in the face of severe weather lies in our ability to communicate the threat and your willingness to react.
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