# Presentation: 606970

## Update on Storm-Based Warnings

**Update on Storm-Based Warnings**

- Partner’s Meeting
- Wednesday, June 20, 2007

- May 8, 2003

- John FerreeNWS Severe Storms Services Leader

## The Weather Warning Partnership

_***The Public***_

- National Weather Service

- News
- Media and Private Sector Meteorologists

- Emergency Management

**Notes:**
Partnership is critical to getting the warning message to the public.

## Why Storm-Based Warnings?

**County-Based Tornado Warnings**
**8 Counties under warning**
**Almost 1 million people warned**

** ****More specific**
** ****Increased clarity**
** ****Supports new****dissemination technology**

**Why Storm-Based Warnings?**

**Three simultaneous tornadoes within line of severe thunderstorms  **

**Storm-Based Tornado Warnings**
**70% less area covered**
**~600,000 fewer people warned**

**Notes:**
The next several slides will address the reason WHY the NWS is going to a SBW system.

First, here is an example to illustrate some of the benefits of going from county-based warning to storm-based warnings. In this case, there were actually three significant tornadoes on the ground at the same time. Eight counties were included in tornado warnings, with almost a million people under a tornado warning. With storm-based tornado warnings, only those area that are threatened are in the warning, not the entire county. In this case, 70 percent less area was covered by warnings, and approximately 600,000 fewer people would encouraged to take immediate cover. A test of storm-based warnings in 2005, actually showed that warning area could be reduced by around 70 percent. There are several other benefits to going to storm-based warnings including being able to increase specificity and clarity with the warning. Since any particular community will be under warning less on average in the new storm-based system, the hope is that over time confidence in NWS warnings will increase, and those under warning will be more likely to take action. 

The more geographically based warnings also are supported by new dissemination technologies. 

## An Extreme Example ofFalsely Alarmed Area

**Severe Thunderstorm Warning for San Bernardino and Riverside County CA**
***3.5 million people***
***27,000 square miles ***
**Threatened Area**
***< 2000 people***
***750 square miles***

**Notes:**
The problem of warning entire counties is especially problematic in the western U.S. where counties are larger. San Bernardino county is the largest county in the U.S. and is 13 times larger than the state of Rhode Island. This warning also included Riverside County. The county warned area is outlined in yellow, and the two counties covered nearly 30,000 Square Miles – about half the state of Illinois, and larger that the entire County Warning Area of 72 WFOs. The storm was not moving very fast and the area of threat was actually very small. The storm-based warning would cover less than 300 square miles, about the size of a small county in northern IL. The warning was disseminated to 3.5 million people while only a few thousand people were threatened by the storm. 

## Delineation Improves FFWs

**Notes:**
Flash Flood Warnings will also be storm-based beginning October 1, 2007, and an reduction in falsely alarmed area is expected for Flash Flood Warnings, also. Here is an example provided by Ken Cook, SOO ICT.  The background image is the Flash Flood Monitoring and Prediction application with the highlighted areas of magenta are areas where rainfall accumulation has exceeded flash flood guidance. Flash flooding is both a meteorological and hydrologic event with not just the areas of heavy rainfall under threat, but also down stream (the streams are in yellow). The white polygon is drawn for just the area  under threat of flash flooding. 

## Feature Tracking Added

**Location and motion of feature**
***Estimated location of tornado, leading edge of gust front, leading edge of hail core, or other.***

**Notes:**
The only major change prior to the implementation is the addition of the feature location and movement in coded format below the latitude and longitude of the polygon vertices. Other enhancements are likely and we will rely on input from the Weather Enterprise for guidance. 

## Outstanding Issues for Storm-Based Warnings

**County Warning Area (CWA) boundaries**
**Multiple warnings in a county**
**Local Storm Report (LSR) improvements**
**CAP format**

**Notes:**
Here are four outstanding issues for storm-based warnings that we are targeting for improvement in the upcoming year. 

## County Warning Area Boundaries

**Notes:**
There are challenges for storm-based warnings that still need to be worked out. In the example the tornadic storm is in Randolph County, IL with is in the St. Louis NWS office forecast and warning area. The storm will be moving NE and impact both portions of Perry County, IL that is in Paducah’s County Warning Area (CWA). In this example, ,having multiple warnings for Randolph, Washington, and Perry county is not ideal. It would be better if the one office could issue a storm-based warning for the entire area. To do this will take extensive operational testing to make sure there is adequate collaboration between offices, and that all dissemination systems are prepared to handle this issue.  

## County Warning Area Boundaries

- Madison

- Bond

- Clinton

- Fayette

- Marion

- St. Clair

- Washington

- Randolph

- Perry

- Jackson

- Franklin

- Jefferson

- Hamilton

- Williamson

- Saline

- Wayne

- Clay

**STL**

**PAH**

**ILX**

**County Warning Area Boundaries**

**Notes:**
There are challenges for storm-based warnings that still need to be worked out. In the example the tornadic storm is in Randolph County, IL with is in the St. Louis NWS office forecast and warning area. The storm will be moving NE and impact both portions of Perry County, IL that is in Paducah’s County Warning Area (CWA). In this example, ,having multiple warnings for Randolph, Washington, and Perry county is not ideal. It would be better if the one office could issue a storm-based warning for the entire area. To do this will take extensive operational testing to make sure there is adequate collaboration between offices, and that all dissemination systems are prepared to handle this issue.  

## Multiple Warnings in One County/Parish

**Issue for text, radio, TV crawls**
**Add reference to other valid warnings**
**Include counties with directional delimiters?**
**Summary severe weather statements?**

- Madison

- Bond

- Clinton

- Fayette

- Marion

- St. Clair

- Washington

- Randolph

- Perry

- Jackson

- Franklin

- Jefferson

- Williamson

**TOR until 3:30PM**

**SVR until 3:45PM**

**Notes:**
A challenge for the listening audience or text only users is when there are multiple warnings over the same county, there is a potential for confusion. In the example, when a listener in Washington county hears that the tornado warning has expired at 3:30PM they will also need to know that the severe thunderstorm warning continues until 3:45PM. This may require a list of other valid warnings appended to each warning at issuance. Another consideration yet to be determined is if there will be summary severe weather statements when multiple warnings are in effect? These are all ideas that will be tested first in simulations, and then in limited real-time situations in consultation with the private sector prior to nationwide deployment.  

## New Requirements forLocal Storm Reports (LSR)

**Individual report output with VTEC ETN**
***Accurate corrections***
**Cumulative report output**
***One line per report (15 reports in 15 lines)***
***Flexible time range (severe reports 18Z – 21Z)***
***Flexible report type (snowfall accumulation)***
**CAP/XML Format**

**Notes:**
Timeliness and accuracy of Local Storm Reports will be an emphasis during the next year. We are also working on some substantial improvements to the LSR listed here.  

## CAP Format

***“******The Order requires EAS participants to accept messages using Common Alerting Protocol (CAP)...****to ensure the efficient and rapid transmission of EAS alerts to the American public in a variety of formats (including text, audio and video) and via different means (broadcast, cable, satellite, and other networks) and to promote the development of Next Generation EAS.”*
- Federal Communications Commission Announcement
- May 31, 2007

**http://****www.eic.org/docs/FCCCAPEASnotice.pdf**

**Notes:**
A related project is to put our warnings in CAP (Common Alerting Protocol) format. This will benefit storm-based warnings by making the warning area digitally available to a wider office, and more flexible to add information. 

## Summary of Outstanding Issues for Storm-Based Warnings

**County Warning Area (CWA) boundaries**
**Multiple warnings in a county**
**Local Storm Report (LSR) improvements**
**CAP format**

**Notes:**
Just to summarize the areas of emphasis on warnings for the upcoming year. 

## www.weather.gov/sbwarnings

**Notes:**
For additional information, including information on progress on the issues presented in this presentation see our web site at www.weather.gov/sbwarnings

## Questions?

**Contact information**
***E-mail:  John.T.Ferree@noaa.gov***
***Phone: 405-325-2209 ***
**Success depends on all of us!**

**Notes:**
Success in terms of how well storm-based warnings will be accepted and applied by the public depends on all of us. Thank you for your attention.