SPC Convective Outlook Changes Changes in Category Names/Definitions Bill Sammler Warning Coordination Meteorologist National Weather Service, Wakefield VA

Storm Prediction Center (SPC) Located in Norman, OK since 1997 Issues Outlooks for Thunderstorms/Severe Thunderstorms and Fire Weather Issues All Tornado and Severe Tstm WATCHES nationwide

Current SPC Outlooks 3 Tiers - SLGT, MDT and HIGH – “See Text” Used for Marginal Situations Increased Coverage and Higher Intensity with MDT/HIGH

Rationale for Proposed Changes Limitations of SEE TEXT and SLGT SLGT, MDT, HIGH have been used for 40 years and have some established understanding. Breakpoint thresholds for these categories remain essentially unchanged Addition of ENH addresses concern about SLGT (word meaning and probabilistic range) Numbers/colors on legend will further aid interpretation Social science informed SPC discussions on the change

Day10%2%5%10%10% sig15%15% sig30%30% sig45%45% sig60%60% sig Tor Wind Hail Day20%5%15%15% sig30%30% sig45%45% sig60%60% sig All Svr Day30%5%15%15% sig30%30% sig45%45% sig All Svr Day4-815%30% All Svr TSTMS SLGT MARGINAL ENHANCED MDT HIGH SPC Severe Weather Outlook Probability-to-Categorical Description Tables (2014) Increase risk categories to 5 levels for Day 1, Day 2, & Day 3 Outlooks Category 1 = MRGL Category 2 = SLGT Category 3 = ENH Category 4 = MDT Category 5 = HIGH Day 1-3 Outlook Changes “sig” = Significant Severe Tstms = Hail 2+ and/or Wind ≥ 65KT/75 MPH

Increase risk categories to 5 levels for Day 1, Day 2, & Day 3 Outlooks Replace See Text with Marginal for lowest risk probabilities (Day 1 - Day 3) Day10%2%5%10%10% sig15%15% sig30%30% sig45%45% sig60%60% sig Tor Wind Hail Day20%5%15%15% sig30%30% sig45%45% sig60%60% sig All Svr Day30%5%15%15% sig30%30% sig45%45% sig All Svr Day4-815%30% All Svr TSTMS SLGT MARGINAL ENHANCED MDT HIGH SPC Severe Weather Outlook Probability-to-Categorical Description Tables (2014) Day 1-3 Outlook Changes “sig” = Significant Severe Tstms = Hail 2+ and/or Wind ≥ 65KT/75 MPH

Increase risk categories to 5 levels for Day 1, Day 2, & Day 3 Outlooks Replace See Text with Marginal for lowest risk probabilities (Day 1 - Day 3) Insert Enhanced between high-end SLGT & low-end MDT probabilities Day10%2%5%10%10% sig15%15% sig30%30% sig45%45% sig60%60% sig Tor Wind Hail Day20%5%15%15% sig30%30% sig45%45% sig60%60% sig All Svr Day30%5%15%15% sig30%30% sig45%45% sig All Svr Day4-815%30% All Svr TSTMS SLGT MARGINAL ENHANCED MDT HIGH SPC Severe Weather Outlook Probability-to-Categorical Description Tables (2014) Day 1-3 Outlook Changes “sig” = Significant Severe Tstms = Hail 2+ and/or Wind ≥ 65KT/75 MPH

Increase risk categories to 5 levels for Day 1, Day 2, & Day 3 Outlooks Replace See Text with Marginal for lowest risk probabilities (Day 1 - Day 3) Insert Enhanced between high-end Slight & low-end Moderate probabilities Add a 15 percent (Slight Risk) to Day 4-8 Outlooks Day10%2%5%10%10% sig15%15% sig30%30% sig45%45% sig60%60% sig Tor Wind Hail Day20%5%15%15% sig30%30% sig45%45% sig60%60% sig All Svr Day30%5%15%15% sig30%30% sig45%45% sig All Svr Day4-815%30% All Svr TSTMS SLGT MARGINAL ENHANCED MDT HIGH SPC Severe Weather Outlook Probability-to-Categorical Description Tables (2014) Day 4-8 Outlook Changes Expected to result in better alignment with WFO forecasts and DSS

13Z Day 1 (Current) 6/1/ Z Day 1 LSRs 6/1/2011 Example of Change (Day 1) 13Z Day 1 (New) 6/1/2011

SPC Outlook Changes Current Timeline for Implementing Changes: September 2014

Building a Weather-Ready Nation Impact Based Warning Experimental Product

Building a Weather-Ready Nation Impact Based Warning Experimental Product Spring 2014 Expansion IBW began in Positive feedback supported expansion to 38 central region offices in Positive feedback supported expansion to 38 central region offices in In 2014, six new offices, including NWS Blacksburg, were added. In 2014, six new offices, including NWS Blacksburg, were added. Expansion is expected in the future. Expansion is expected in the future. IBW began in Positive feedback supported expansion to 38 central region offices in Positive feedback supported expansion to 38 central region offices in In 2014, six new offices, including NWS Blacksburg, were added. In 2014, six new offices, including NWS Blacksburg, were added. Expansion is expected in the future. Expansion is expected in the future.

Building a Weather-Ready Nation Impact Based Warning Experimental Product Goals: Provide additional valuable information to media and Emergency Managers Provide additional valuable information to media and Emergency Managers Facilitate improved public response and decision making Facilitate improved public response and decision making Better meet societal needs in the most life-threatening weather events Better meet societal needs in the most life-threatening weather events

Building a Weather-Ready Nation Impact Based Warning Experimental Product Intended Outcomes: Optimize the convective warning system within the existing structure Optimize the convective warning system within the existing structure Motivate proper response to warnings by distinguishing situational urgency Motivate proper response to warnings by distinguishing situational urgency Realign the warning message in terms of societal impacts Realign the warning message in terms of societal impacts Communicate recommended actions/precautions more concisely Communicate recommended actions/precautions more concisely Evaluate ability to distinguish between low impact and high impact events Evaluate ability to distinguish between low impact and high impact events 2011 Raleigh EF3 Tornado?

Building a Weather-Ready Nation Impact Based Warning Experimental Product

Building a Weather-Ready Nation Tornado – Radar Indicated or Observed Impact Based Warning Examples

Building a Weather-Ready Nation Tornado – Tag: Considerable Impact Based Warning Examples

Building a Weather-Ready Nation Tornado – Tag: Catastrophic Impact Based Warning Examples

Building a Weather-Ready Nation Severe Thunderstorm Warning: Tornado Possible Impact Based Warning Examples

Building a Weather-Ready Nation Impact Based Warning Experimental Product Enhancements By: Improving communication of critical information Improving communication of critical information Making it easier to quickly identify the most valuable information Making it easier to quickly identify the most valuable information Enabling users to prioritize the key warnings in your area of interest Enabling users to prioritize the key warnings in your area of interest Providing different levels of risk within the same product Providing different levels of risk within the same product Enabling the NWS to express a confidence level of potential impacts Enabling the NWS to express a confidence level of potential impacts

Building a Weather-Ready Nation Impact Based Warning Experimental Product Evaluation: Performed by social science research groups and National Weather Service Performed by social science research groups and National Weather Service Using focus groups and surveys Using focus groups and surveys Media partners Media partners Emergency Management Emergency Management Public Public NWS Forecasters NWS Forecasters

Building a Weather-Ready Nation Impact Based Warning Experimental Product

The End!! Are There Any Additional Questions?