Department of Commerce ·National Oceanic & Atmospheric Administration ·National Weather Service NATIONAL WEATHER SERVICE INSTRUCTION 10-513 SEPTEMBER 28, 2017 Operations and Services Public Weather Services, NWSPD 10-5 WFO WINTER WEATHER PRODUCTS SPECIFICATION NOTICE: This publication is available at: http://www.nws.noaa.gov/directives/. OPR: W/AFS21 (D. Soroka) Certified by: W/AFS21 (M. Hawkins) Type of Issuance: Routine SUMMARY OF REVISIONS: This instruction supersedes NWSI 10-513, “WFO Winter Weather Products Specification,” effective October 12, 2015. Many of the changes in this version directly relate to the Hazard Simplification effort to consolidate and reformat the Winter Weather Product suite. The following revisions were made to this instruction: 1. Amended Section 2.1 to add examples of winter weather events. 2. Replaced Section 3 title “Multi-tiered Concept” with “Winter Weather Product Headlines” and included language describing forecast certainty and severity. 3. Removed Blizzard Watch, Lake Effect Snow Watch, Freezing Rain Advisory and Lake Effect Snow Advisory from Table 1 and added “Eastern Region WFOs only” for Lake Effect Snow Warning. 4. Amended definition of Winter Storm Watch and Winter Weather Advisory in Table 1. 5. Amended wording above Table 1 regarding product criteria. 6. Amended Section 6.2.2.5 to eliminate additional wording for multiple segments. 7. Modified Table 2 to include only Winter Storm Warning criteria and warning decision methodology. 8. Amended wording in Section 6.2.4 to more accurately reflect valid time. 9. Added paragraph in Section 6.2.2.4 to introduce format of Winter Weather Messages. 10. Amended Section 6.3.4.1 to make overview as concise as possible. 11. Replaced Figure 1 with Table 4 and amended product format example. 12. Amended and added to Section 6.3.4.2.2 to include new mandatory descriptive text. 13. Removed wording in Section 6.4.1 regarding Watch Update Time. 14. Removed Sections 6.6.2 and 6.6.2.1. 15. Amended Lake Effect Snow Watch to Wind Chill Watch headline example in Appendix C on page C-1. 16. Provided all new product examples in Appendix A with new format. 17. Amended NWS Southern and Eastern Region’s Winter Storm Warning Snow Criteria table and/or maps and added NWS Eastern Region’s Winter Weather Advisory Snow Criteria in Appendix D. Signed 9/14/2017 Andrew D. Stern Date Director Analyze, Forecast and Support Office NWSI 10-513 SEPTEMBER 28, 2017 WFO Winter Weather Products Specification Table of Contents 1 Introduction ............................................................................................................................... 1 2 Winter Weather Event and Definitions ..................................................................................... 1 2.1 Winter Weather Event ...................................................................................................... 1 2.2 Winter Weather Event Beginning Time ........................................................................... 1 2.3 Winter Weather Event Ending Time ................................................................................ 1 3 Winter Weather Product Headlines .......................................................................................... 1 3.1 Outlook ............................................................................................................................. 1 3.2 Watch ................................................................................................................................ 1 3.3 Warning and Advisory...................................................................................................... 1 4 Forecaster Judgment ................................................................................................................. 2 5 Winter Storm Outlook (product category HWO) ...................................................................... 2 5.1 Mission Connection .......................................................................................................... 2 5.2 Issuance Guidelines .......................................................................................................... 2 5.3 Technical Description ....................................................................................................... 2 6 Winter Weather Watches, Warnings and Advisories (Product Category WSW) ..................... 2 6.1 Mission Connection .......................................................................................................... 2 6.2 Issuance Guidelines .......................................................................................................... 2 6.2.1 Creation Software ................................................................................................. 2 6.2.2 Issuance Criteria ................................................................................................... 2 6.2.2.1 Winter Weather Watch Issuance Criteria ............................................ 2 6.2.2.2 Winter Weather Warning and Advisory Criteria ................................. 3 6.2.2.3 Impact Criteria ..................................................................................... 3 6.2.2.4 Winter Weather Products ..................................................................... 3 6.2.2.5 Multiple Segments ............................................................................... 5 6.2.2.6 Forecast Snowfall/Sleet Criteria .......................................................... 5 6.2.3 Issuance Time ....................................................................................................... 5 6.2.3.1 Winter Storm Watch Issuance Time .................................................... 5 6.2.3.2 Winter Weather Warning/Advisory Issuance Time ............................. 6 6.2.4 Valid Time ............................................................................................................ 6 6.2.4.1 Event Beginning Time ......................................................................... 6 6.2.4.2 Event Ending Time .............................................................................. 6 6.2.5 Product Expiration Time ....................................................................................... 6 6.2.5.1 Watch Expiration Time ........................................................................ 6 6.2.5.2 Warning or Advisory Expiration Time ................................................ 6 6.3 Technical Description ....................................................................................................... 7 6.3.1 UGC Type............................................................................................................. 7 6.3.2 Mass News Disseminator (MND) Broadcast Instruction Line ............................. 7 6.3.3 MND Product Type Line ...................................................................................... 7 6.3.4 WSW Content ....................................................................................................... 7 NWSI 10-513 SEPTEMBER 28, 2017 6.3.4.1 Overview Section ................................................................................ 7 6.3.4.1.1 Overview Headline ............................................................. 7 6.3.4.1.2 Overview Text .................................................................... 7 6.3.4.2 Segmented Forecast Information ......................................................... 7 6.3.4.2.1 Watch, Warning, Advisory Headline .................................. 7 6.3.4.2.2 Descriptive Text (see Table 4 for message format) .......... 10 6.3.4.2.3 Order of Segments ............................................................. 11 6.3.4.2.4 Order of Headlines ............................................................ 11 6.3.5 Format ................................................................................................................. 13 6.4 Updates, Cancellations and Corrections ......................................................................... 13 6.4.1 Minimum Watch Update Time Frame ................................................................ 14 6.4.2 Minimum Warning/Advisory Update Times Frame ........................................... 14 6.5 Upgrades ......................................................................................................................... 14 6.5.1 Upgrade Watch to Warning or Advisory ............................................................ 14 6.5.1.1 Upgrade Watch to Warning Example ................................................ 14 6.5.2 Upgrade Advisory to Warning ........................................................................... 15 6.5.2.1 Upgrade Advisory to Warning Segment Example ............................. 15 6.5.3 Upgrade Warning with a Warning ..................................................................... 15 6.5.3.1 Upgrade Warning to a Warning Segment Example ........................... 15 6.6 Replacing Warning or Advisories .................................................................................. 16 6.6.1 Replacing Warning with a Warning when not an Upgrade ................................ 16 6.6.1.1 Replace Ice Storm Warning with Winter Storm Warning Segment .. 16 APPENDIX A. Winter Weather Product Examples .................................................................. A-1 APPENDIX B. Winter Weather Definitions ............................................................................