Severe Hazards Analysis & Verification Experiment

(SHAVE)

Kevin ScharfenbergOU-CIMMS & NOAA-NSSL

2nd Workshop on NWS Severe Weather Warning Technology -- 11 July 2007 -- Norman, OK

SHAVE 2006

•Goal: Collect high temporal and spatial resolution data that describe the distribution of hail sizes in hail swaths produced by thunderstorms

• Verification and validation of multi-radar/multi-sensor hail algorithms

Severe HAil & Verification Experiment 2006

SHAVE 2006

More SHAVE 2006 goals:

• Use high-resolution verification data in the development of techniques for probabilistic warnings of severe thunderstorms

• Associate changes in the hail size distribution with storm evolution

• Enhance climatological information about hail in the United States

SHAVE 2006

Data sources:

Google Earth (business locations and phone numbers)

Rural phone directories (selected counties with plat maps)

SHAVE 2006 results

Data collection days 83

Total phone calls 13854

“Good” data points 4880

“Good” except time 658

Hail w/ questionable location 42

Hail w/ questionable size 371

Busy / intercept operator 777

Wrong location 47

No answer or machine 5485

Disconnected / Do Not Call 1286

Other 307

Areal resolution:

~ 1 point / 59 km2

Temporal resolution:

~ 1 point / 3.1 minutes

Storm Data problemsSHAVE verification calls during summer 2006

Storm Data problems

Storm Data reports:1 tornado, 1.75” hail

SHAVE hail reports (~35)

Storm Data problems

Storm Data problems

SHAVE 2007

Severe Hazards Analysis & Verification Experiment 2007

+ Expand effort to include wind and tornado damage swaths+ Focus on verification for Oklahoma resources (PAR, CASA, KOUN, etc.)

New resources:• Online media (streaming local TV coverage, local newspapers, newswires)• SpotterNetwork.org• Delorme Street Atlas 2007 residential phone database• Digital locators (county assessor databases, 411.com)

SHAVE 2007

Setting an aggressive agenda for change

Argument: Change is needed

Existing storm database resolution and associated verification methods are incompatible with planned resolution of “warn-on-forecast” models and gridded threat-based warnings

Our ability to resolve features is outpacing our ability to document them

Setting an aggressive agenda for change

For discussion:

Gridded, probabilistic verification

- Probability of exceedance- Initialized by computer model/algorithm- Calibrated by nearby reports & human analysis- Reports still catalogued - Multimedia, online, collaborative, near-real-time data portal (e.g., wiki)

Kevin.Scharfenberg@noaa.gov