1. Roger Edwards (SPC) and Greg Carbin (WPC)
ESTIMATED CONVECTIVE WINDS: RELIABILITY and EFFECTS on SEVERE-STORM CLIMATOLOGY
Roger Edwards (SPC) and Greg Carbin (WPC)
Title

2. DATA BACKGROUND SPC FINAL SEVERE-STORM DATASET
CONVECTIVE WIND-SPEED DATA (NOT DAMAGE)
15,145 “MEASURED” GUSTS (KT)
135,188 “ESTIMATED” GUSTS (KT)
EXPLICIT TAGS: 2006–2015, 10 YEARS of DATA
NO SYSTEMATIC INSTRUMENT-CALIBRATION INFO in STORM DATA, SOURCE SOMETIMES NOT SPECIFIED
MISCLASSIFICATIONS UNKNOWN BUT POSSIBLE BASED on MILLER et al. (2016) NONCONVECTIVE-WIND STUDY
2010 POPULATION DATA for STATE BREAKDOWNS
AGDAS et al. (2012) WIND-TUNNEL TESTS on HUMANS

3. DATA BACKGROUND
Before 2006
2006-Present

4. TSTM-GUST DISTRIBUTION: LOG SCALE

5. TSTM-GUST DISTRIBUTION: LOG SCALE

6. TSTM-GUST DISTRIBUTION: LOG SCALE
SVR criteria
1 mph above SVR criteria, 2 orders of magnitude fewer EGs
CLIMATOLOGY INFLUENCES: Arbitrary thresholds Hidden errors
Integers 0 and 5

7. MEASURED-GUST DISTRIBUTION: LINEAR SCALE?

8. MEASURED-GUST GEOGRAPHY: 15,145

9. ESTD-GUST GEOGRAPHY: 135,188

10. COMBINED GEOGRAPHY

11. MEASURED-GUST GEOGRAPHY

12. MEASURED vs. ESTD: HUMAN FACTOR HOW GOOD ARE HUMAN WIND ESTIMATES?
54 mph
OPERATIONAL, FIELD & RESEARCH EXPERIENCE WITH TSTM WIND ― AND THE DATA ― COMPEL US TO ASK:
HOW GOOD ARE HUMAN WIND ESTIMATES?

13. MEASURED vs. ESTD: HUMAN FACTOR
Doswell et al. (2005): “Human observers typically overestimate the wind speed, owing to a lack of experience with extreme winds.”
Miller et al. (2016, in press): synoptic wind events, GHCN observed vs. mesoβ-proximal human estimates: ≈ 1.33 overestimation factor
Agdas et al. 2012: 76 subjects in wind-tunnel 10–60 mph in random order. ≈ 1.25 perceived/ actual (P/A) ratio.
Testing under truly convective conditions is practically impossible.

14. MEASURED vs. ESTD: HUMAN FACTOR Adapted from Agdas et al. (2012)
Human Subjects
≈1.25 OVER
Adapted from Agdas et al. (2012)

15. APPLYING 1.25 P/A RATIO to DATA
Extrapolated A12 curve, still 1.25 P/A at higher speeds, apply to TSTM-wind data
1.25 P/A ratio may be conservative based on nonconvective study (Miller et al. 2016).
Values <73 mph (126,474) drop out of “severe” database
Only 7% of EG data would remain as severe
Only a few 73–74-mph EGs, thus, effectively: EGs less than hurricane force are NON- SEVERE for bulk analysis.

16. ISSUES & IMPLICATIONS
ARTIFACTS: Human estimators preferentially offer values at minimal severe thresholds or “0 and 5”. What do we do?
Many implications for data mapping, weighting, research use, forecast verification, calibration of CAM-based guidance.
Should bulk EG counts be reduced by factor of 10?
How should verification metrics be weighted away from estimates (toward measured)?
Should EG coverage be detrended by corresponding density of MGs in same regions or states, to normalize in verifying outlooks and watches?
Should EGs be used at all—or be reduced by 1.25 in research and even in parallel, on report logs?
Should EGs not hurricane-strength be discarded for verification and/or research use?
Defining NSTC convective mode

17. Research Contact: Roger.Edwards@noaa.gov
DATA:
DOCUMENTATION:
Research Contact:
Where to get data and info