New Severe Warning Guidelines to be Tested
by Cody Matz
March 05, 2013 6:45 PM
Its severe weather awareness week across the country, granted a little early for South Dakota. But a new impact based warning system will be tested across much of the central portions of the country. Its not something that anyone ever hopes to use, but realistically, that’s just not feasible considering dangerous weather is a guarantee at some point in the year in almost every part of the U.S. This new system isn’t much different from what is currently being used across the country, but the National Weather Service hopes that the slight differences may give some vital information that could ultimately save lives. The article below is from the National Weather Service and goes over what they are changing and why.
(The areas of the country participating in this test)
OVERVIEW / Background
2011 proved to be a historic year in terms of the number of tornado fatalities across the United States with over 550 fatalities. The May 22, 2011, Joplin tornado resulted in 158 of those, making it the deadliest single tornado since modern record keeping began in 1950. Following the historic Joplin tornado, the National Weather Service (NWS) conducted a service assessment for the purpose of evaluating NWS warnings and societal response to those warnings.
KEY FINDINGS FROM THE 2011 JOPLIN ASSESSMENT
The majority of people identified local outdoor warning systems as their first source of warning.
The majority of people sought confirmation from additional sources before seeking shelter.
Credible, extraordinary risk signals prompt people to take protective actions.
To address these findings the NWS Central Region will expand to all their offices the impact based convective warning experimental product to better communicate threats to partners and constituents. The goals in this multi-step process are to provide more information to media and EM partners, to facilitate improved public response and decision making; and to better meet societal needs in the most life-threatening weather events. Any effort to change core convective warning products must operate under tight restrictions, including time constraints and procedural limitations. In addition, any radical changes to the convective warning products would demand a rather large adjustment by core customers and partners; and a massive public education effort. Therefore, this demonstration will work within the boundaries of the well-established weather enterprise infrastructure to ensure easy absorption into mass communication channels. Initial efforts will build upon pre-existing Central Region efforts to employ “event tags” at the bottom of each severe thunderstorm and tornado warning. The additional event tags will contain more specific threat information as a quick means to provide users and partners with potential high impact risk signals that prompt faster risk assessment and protective action.
INTENDED OUTCOMES OF THE IMPACT BASED WARNING DEMONSTRATION
Optimize the convective warning system within the existing structure
Motivate proper response to warnings by better distinguishing situational urgency
Realign the warning message in terms of societal impacts
Communicate recommended actions/precautions more concisely
Evaluate NWS ability to distinguish between low impact and high impact convective events
Impact Based Warnings will Enhance Current Efforts
1. Impact Based Warnings will improve communication of critical information
2. Enhanced format will make it easier and quicker to identify the most valuable information
3. Will enable you to prioritize warnings in your area of interest
4. Provides different levels of potential impact within the same product
5. A particular warning might highlight a storm that is particularly dangerous
6. Allows users and vendors to develop apps and tools for the public and broadcast meteorologists to better communicate areas of increased risk
7. Tags will enable the NWS to express a level of confidence of potential impacts
The following is what one of these warnings would look like if printed out and put into paragraph style. The areas that are being tested are shaded in red.
Evidence on radar and near storm environment is supportive, but no confirmation.
Tornado is confirmed by spotters, law enforcement, debris ball signature, etc.
Tornado Damage Threat Tag
TORNADO DAMAGE THREAT...CONSIDERABLE
When there is credible evidence that a tornado, capable of producing considerable damage, is imminent or ongoing.
TORNADO DAMAGE THREAT...CATASTROPHIC
When a severe threat to human life and catastrophic damage from a tornado is occurring, and will only be used when reliable sources confirm a violent tornado.
Tornado Tags for Severe Thunderstorm Warnings
A severe thunderstorm has some potential for producing a tornado although
forecaster confidence is not high enough to issue a Tornado Warning.