Polygon Media Outreach

PolygonsA New Direction in the Warning Process: 

Polygons A New Direction in the Warning Process (Name) National Weather Service (Office)

Overview: 

Overview The advantages of polygon warnings What are the issues concerning the polygon? What is currently being done Who is doing the work Future Plans

Slide3: 

To provide geographically concise, timely, and meteorologically accurate warning information to all. Our Vision

Test and Evaluation: 

Test and Evaluation The test and evaluation period runs from March 1 to October 1, 2005 Five to six NWS offices from each of the CONUS regions will participate Feedback will be solicited from customers to assist in our evaluation Results and recommendations will be forwarded to NWSHQ at the end of the year

So What’s the Issue?: 

So What’s the Issue? Warnings are issued for entire counties based on legacy communication systems. A vast customer base is familiar with county based warnings (e.g., Emergency Managers and media). Warning generation software is designed for county warnings. Lat/lon polygons located within the warning text require external display software. Polygon display capability limited today

Define the Polygon: 

Define the Polygon The Polygon represents the area of maximum threat ie. The area that is truly most at risk from impending severe weather The Polygon consist of a set of 4 or more latitude and longitude points that can be displayed graphically

Polygon Advantages: 

Polygon Advantages Shows specifically where the threat is More accurately shows warning area on systems displaying warnings graphically Reduction of risk area to public Better graphical description capabilities Wider local distribution via cell phones, PDAs, etc. Increase NWS role in the confirmation part of the warning process Private sector starting to turn to polygons Allows us to track and set goals for false alarm area Better warning quality Keeps NWS in technological step

The Need For Polygons: 

The Need For Polygons A study by Mileti and Sorenson (1990) suggested: People do not take cover solely based on NWS warnings NWS warnings start the “confirmation process”, by which people: Look outside to determine if they are in imminent danger Turn on local media to confirm they are in imminent danger (particularly at night). Graphical warning displays can assist in the confirmation process by narrowing the warning to the highest threat area. Emergency officials can plan use of resources better by utilizing more specific graphical warnings Local media can use graphical products to refine the threat area. Private sector sources of warning alerts (e.g. First Alert) could use graphical information to refine their alerts in the future.

Typical Polygon and Associated County Warnings: 

Typical Polygon and Associated County Warnings Latitude/Longitude points are at the bottom of all TOR’s, SVR’s, FFW’s, SVS’s, and SMW’s. One Polygon, three counties…can you do a quick comparison of the areal coverage of the polygon vs the counties?

Polygon Advantages: 

Polygon Eliminates Area False Alarmed Polygon Advantages

One WFOs Study (2004): 

One WFOs Study (2004) In 2004, issued tornado warnings for counties that covered: 31,990 square miles Included 494 individual towns Utilizing the polygon approach, the polygons covered: 9,500 square miles Included 152 individual towns If the polygon approach were in place: Would have reduced our total warning area by 22,490 square miles Would have unnecessarily warned 242 fewer towns That's a reduction of 70%!

Demographic Information May Be Available To Customers via Software Enhancements: 

Demographic Information May Be Available To Customers via Software Enhancements

Better Warning Information: 

Better Warning Information

No Issue is Trivial: 

No Issue is Trivial 2 maps of all Polygon Warnings Issued in 2003 Can you see the counties? What does this tell you about how we are currently doing business?

We Have A Tendency To Align Polygons To County Borders: 

We Have A Tendency To Align Polygons To County Borders

So How Do We Fix This?: 

So How Do We Fix This? The test and evaluation offices will be given extensive training on: Evaluating the situation Localized Widespread More development expected Identifying meteorologically what is occurring Speed and Movement Intensification Dynamics Local Influences Applying the meteorology Drawing the appropriate polygon for the area of maximum threat And of course, conduct a test and evaluation

Where will the training lead us?  Let’s Look At An Example: 

Where will the training lead us? Let’s Look At An Example Consider the supercell below, moving steadily eastward. Assume the storm is producing large hail and severe winds, and may soon produce a tornado at the location of the hook signature. What is the best polygon procedure from choices given on the next slide? (Thick orange box highlights Sumner County.)

Which of the following is best?: 

Which of the following is best? A. TOR for Sumner Co. B. TOR for tornado threat C. Initial SVR for entire area, SVR to the north storm, TOR for the for the hail. tornado threat area. = SVR = TOR

Which of the following is best?: 

Which of the following is best? = SVR = TOR A. TOR for Sumner Co. A is the worst choice of the three because: -- Over half of tornado warning covers areas not really threatened by a tornado. -- Tornado warning does not include the hail/wind threat from the storm, though it may be implied.

Which of the following is best?: 

Which of the following is best? = SVR = TOR B. TOR along the expected tornado track, SVR to the north for the hail. B is a better choice because: -- tornado warning covers the area really threatened by a tornado. -- hail threat to the north covered by a SVR, where minimal tornado threat. BUT, what if you get severe rear-flank downdraft winds south of TOR area? Issue a third warning (SVR)? Talk about potential for confusion!

Which of the following is best?: 

Which of the following is best? = SVR = TOR C. Initial SVR for entire storm, TOR along the expected tornado track. C may be the best choice. Initially issue a SVR for the entire storm (all areas where hail/wind may occur). Then, as tornado threat develops, issue a TOR covering the true area threatened by the developing tornado. --- So, you would have 2 warnings in effect for the same county, but for different areas, and for different weather conditions. --- In this example, you could issue a SVR for Sumner County, but issue the TOR for southern or southeastern Sumner County.

Won’t this cause confusion?: 

Won’t this cause confusion? = SVR = TOR C. Initial SVR for entire storm, TOR along the expected tornado track. Won’t “double warnings” cause confusion? Why not simplify with just a single TOR? Is this any different than issuing both a tornado warning and a flash flood warning? Would it be different if we renamed SVR’s “Wind-and-Hail Warnings”? As long as we are “county”-centric, confusion is possible. If we get away from “counties”, and focus on specific areas, and specific weather conditions, we can provide a better service.

Who’s Doing The Work?: 

Who’s Doing The Work? A broad spectrum of NWS personnel consisting of: Meteorologists Hydrologists Data Managers/Developers Verification experts

THE FUTURE: 

THE FUTURE Warnings will be graphically generated Both text and graphical warnings created. Warnings are focused on specific area(s) threatened, independent of geopolitical boundaries. Polygon display software currently being used by broadcast media in some locations will expand Weather Data , WSI Barons, Meteorologix Graphical displays via weather radios, cell phones, PDAs, etc.

SUMMARY: 

SUMMARY The polygon approach allows: 1) refinement of warnings to areas where the true threat exist 2) production of graphical and text information in support of the “confirmation” process 3) support for weather radio evolution to alert for areas smaller than counties. 4) the private sector to develop/display graphical warning information and systems for wider distribution We may issue more warnings/false alarms, but we should be able to decrease the total false alarm area. The size of the polygon should relate to the location and extent (in time and space) of the threat.

Questions: 

Questions (your name)@noaa.gov (your phone number)