1. POLYGON WEATHER WARNINGS – A NEW APPROACH FOR THE NATIONAL WEATHER SERVICE Ken Waters National Weather Service, Honolulu HI *, J. M. Coyne, P. L. Wolf, J. T. Schaefer, J. M. Looney, S. Naglic, B. W. MacAloney II, M. A. Tew, J. Lorens, R. J. Okulski, and N. O. Schwein Jan 12, 2005 AMS – San Diego

2. Ken Waters, NWS Pacific Region Background National Weather Service issues four types of short-fused warnings: Tornado Warnings (TOR) Severe Thunderstorm Warnings (SVR) Flash Flood Warnings (FFW) Special Marine Warnings (SMW) Issued normally for one county at a time Can lead to a large false-alarm area, especially in the case of large or irregular-sized counties Verification has been strictly county-based Legacy dissemination methods all tied to counties: NOAA All-Hazards/Weather Radio Uses SAME alert code based on counties Internet displays – again, based on counties

3. Ken Waters, NWS Pacific Region WARNGEN Allows forecaster to graphically highlight the area of greatest threatAllows forecaster to graphically highlight the area of greatest threat Creates a template text product for the warning, including proper headers, issue/expiration times, county UGC codesCreates a template text product for the warning, including proper headers, issue/expiration times, county UGC codes ALSO: includes latitude/longitude vertex points for the pathcast, or polygon warning --- LITTLE USED by NWS, partners, and publicALSO: includes latitude/longitude vertex points for the pathcast, or polygon warning --- LITTLE USED by NWS, partners, and public

4. Ken Waters, NWS Pacific Region

5. NWS Polygon Team formed in 2004 NWS Polygon Team formed in 2004 Purpose: Encourage warnings by polygon rather than county- based Purpose: Encourage warnings by polygon rather than county- based Test will be run in 2005 with some NWS forecast offices Test will be run in 2005 with some NWS forecast offices De-emphasis on county bordersDe-emphasis on county borders Focus on location of severe threatFocus on location of severe threat Test alternate measures of verification that are polygon- basedTest alternate measures of verification that are polygon- based Will open the door for dissemination using current technologies (e.g., cell phones, pagers, GPS-enabled devices)Will open the door for dissemination using current technologies (e.g., cell phones, pagers, GPS-enabled devices)

6. Ken Waters, NWS Pacific Region Using GIS with Polygon Warnings Polygon vertices well-suited to include in GIS Polygon vertices well-suited to include in GIS Mechanism was established to strip off the lat- long polygon information, database the polygons, and create real-time GIS shapefiles Mechanism was established to strip off the lat- long polygon information, database the polygons, and create real-time GIS shapefiles Using only open source (“freeware”) software Using only open source (“freeware”) software Code written in PerlCode written in Perl Polygon values formatted in ESRI “gen” formatPolygon values formatted in ESRI “gen” format Use “gen2shp” and “txt2dbf” packagesUse “gen2shp” and “txt2dbf” packages

7. Ken Waters, NWS Pacific Region And now, some examples, using 2004 warnings

8. Ken Waters, NWS Pacific Region

9. Tornado Warnings

10. Ken Waters, NWS Pacific Region Tornado Warnings

11. Ken Waters, NWS Pacific Region Severe Thunderstorm Warnings

12. Ken Waters, NWS Pacific Region Severe Thunderstorm Warnings

13. Ken Waters, NWS Pacific Region Tendency to align warnings to county borders continued in 2004

14. Ken Waters, NWS Pacific Region Flash Flood Warnings

15. Ken Waters, NWS Pacific Region Special Marine Warnings

16. Ken Waters, NWS Pacific Region Warning Shapefiles Updated every minute for TOR, SVR, FFW, SMW, as well as SPC watches Updated every minute for TOR, SVR, FFW, SMW, as well as SPC watches Available at: Available at: http://www.prh.noaa.gov/hq/regsci/gishttp://www.prh.noaa.gov/hq/regsci/gishttp://www.prh.noaa.gov/hq/regsci/gis Ken Waters Regional Scientist NWS Pacific Region Honolulu, Hawaii Ken.waters@noaa.gov (808) 532-6413