1. NCAR Auto-Nowcaster Convective Weather Group NCAR/RAL

2. Why We Need ANC ?

3. Detection and extrapolation of surface convergence boundaries …. ….that trigger thunderstorm initiation and impact storm evolution. The Auto-nowcaster System is unique in its ability to provide nowcasts of storm initiation by…..

4. Example of Auto-Nowcaster Initiation Forecast 1 hour forecastVerification Initiation nowcasts extrapolation nowcasts

5. Weather Forecast Office Washington DC Sydney Australia Forecast Office U. S. Army White Sands Missile Range Central U. S. for the FAA Where has the Auto-nowcaster been demonstrated ? Process of being transferred to: Bureau Meteorology Beijing China U.S National Weather Service – Dallas Weather Forecast Office AWIPS

6. AREA WEATHER UPDATE NATIONAL WEATHER SERVICE FORT WORTH TX 310 PM CDT SUN APR 10 2005 > WARNING DECISION UPDATE FOR NORTH TEXAS MESOANALYSIS PROGRAMS SHOW 1000-1500 J/KG CAPE ALONG AND JUST AHEAD OF DRYLINE. THUS...CU/DEVELOPING STORMS ALONG/E OF DRYLINE SHOULD CONTINUE TO INTENSIFY. STORM INITIATION TOOL ALSO SUGGESTS HIGH POSSIBILITY OF DEVELOPMENT FARTHER SW...OVER CORYELL/LAMPASAS COUNTY AREA. DEEP-LAYER SHEAR MORE THAN SUFFICIENT FOR ORGANIZED STORMS AND AT LEAST MID-LEVEL MESOS. AS STORMS EVOLVE INTO THE EVENING...A MORE LINEAR MODE IS EXPECTED. Auto-Nowcaster at Ft. Worth WFO

7. Data Sets Radar WSR-88D Satellite Mesonet Profiler Sounding Numerical Model Lightning Analysis Algorithms Predictor Fields Forecaster Input Fuzzy Logic Algorithm - Membership functions - weights - Combined likelihood field Final Prediction Flow Chart for the Auto-Nowcaster System

8. Data Sets Radar WSR-88D Satellite Mesonet Profiler Sounding Numerical Model Lightning Analysis Algorithms Predictor Fields Forecaster Input Fuzzy Logic Algorithm - Membership functions - weights - Combined likelihood field Final Prediction Flow Chart for the Auto-Nowcaster System

9. Convergence line Example of fuzzy logic Predictor Field 1.5 Likelihood Lifting Zone Membership Function Lifting Zone Likelihood Yes No.5 0

10. Convergence Predictor Field 2 Membership Function Convergence Likelihood.1.2.3.2.1 Likelihood

11. Cumulus clouds Predictor Field 3.4 -.5 Likelihood Membership Function Cumulus cloud type Likelihood.4 1.8 -.5

12. Likelihood 1 Likelihood 2 Likelihood 3 Weight 1Weight 2 Weight 3 Σ Final combined likelihood of initiation

13. Environmental conditions (RUC) –Frontal likelihood –Layered stability –CAPE (max between 900 and 700 mb) –Mean 875 to 725 mb Relative Humidity Boundary-layer –Convergence –LI (based on METARS) –Vertical velocity along boundary (maxW) –Boundary-relative steering flow –New storm development along boundary Clouds –Clear or Cumulus –Vertical develop as observed by drop in IR temps Blue Regions - Little chance of storm development Green Regions - Moderate likelihood Red Regions - Areas of forecast initiation Predictor Fields used for Combined Likelihood of Initiation

14. 60 Minute Initation (rules with satellite data) Wt: 0.17 Range: -0.085 to 0.17 Wt: 0.20 Range: -0.20 to 0.02 Wt: 0.17 Range: -0.17 to 0.17 Wt: 0.10 Range: 0 to 0.10 Wt: 0.08 Range: -0.02 to 0.08 Wt: 0.16 Range: -0.08 to 0.16

15. 60 Minute Initation (rules with satellite data)Cont. Wt: 0.20 Range: -0.2 to 0.2 Wt: 0.20 Range: 0 to 0.20 Wt: 0.20 Range: 0 to 0.20 Wt: 0.25 Range: 0 to 0.25 Wt: 0.15 Range: 0 to 0.15

16. 60 Minute Initation (rules with satellite data)Cont. Lake: Wt: 0.10 Range: -0.10 to 0 Sat_Clear: Wt: 0.40 Range: -0.40 to 0 Boundary Collision: Wt: 0.12 Range: 0 to 0.12 Initiation Levels: 0.70 => Init 1 0.90 => Init 2 1.20 => Init 3

17. 60 Minute Initation (rules without satellite data) Wt: 0.19 Range: -0.095 to 0.19 Wt: 0.20 Range: -0.20 to 0.02 Wt: 0.19 Range: -0.19 to 0.19 Wt: 0.10 Range: 0 to 0.10 Wt: 0.08 Range: -0.02 to 0.08 Wt: 0.18 Range: -0.09 to 0.18

18. 60 Minute Initation (rules without satellite data)Cont. Wt: 0.21 Range: -0.21 to 0.21 Wt: 0.21 Range: 0 to 0.21 Wt: 0.30 Range: 0 to 0.30

19. 60 Minute Initation (rules without satellite data)Cont. Lake: Wt: 0.10 Range: -0.10 to 0 Sat_Clear: Wt: 0.40 Range: -0.40 to 0 Boundary Collision: Wt: 0.14 Range: 0 to 0.14 Initiation Levels: 0.70 => 25 dBZ 0.90 => 30 dBZ 1.20 => 32 dBZ

20. 60 Minute Growth and Decay Wt: 0.30 Range: -0.3 to 0.3 Lake: Wt: 0.20 Range: -0.20 to 0 Wt: 0.21 Range: -0.21 to 0.21 Wt: 0.15 Range: -0.0375 to 0.15 Wt: 0.20 Range: -0.20 to 0.20 Growth/Decay Levels: decay 6km -0.75 to -0.55 => decay 4km -0.55 to -0.35 => decay 2km -0.35 to 0.20 => steady 0.20 to 0.50 => grow 2km 0.50 to 70 => grow 4km >0.70 => grow 6km

21. Predictor Fields Large-Scale Environment B-L characteristics Satellite Cloud Typing Boundary characteristics Cumulus development Storm motion and trends

22. Predictor Fields Large-Scale Environment B-L characteristics Satellite Cloud Typing Boundary characteristics Cumulus development Storm motion and trends

23. Why do we need a forecaster in the loop?? Forecasters see the larger picture –Conceptual Models –Ignore bad data points –Understand limitations of NWP and observations

24. FAA RCWF Domain June 12, 2003 Forecaster Entered Boundary

25. Draw Tool

27. Entering a convergence boundary in real time is as simple as this demonstration!

28. Forecaster-tools Boundary Entry

29. Forecaster Entered Polygons

30. Ft. Worth WFO April 5, 2005 ForecastVerification

31. Evaluation of Initiation Cases - 2004 Forecaster on duty Convection within ANC domain that increased (based on area coverage) >20% in an hour. Covered an area of 3,000 km 2 (Valid Time).

32. Initiation/Growth Cases 34 Case Days (Ranging from 18 to 210 min – not always consecutive) Divided into 3 categories: –Initiation along line (13) –Initiation in a region (6) –Primarily Growth (15) Initiation along line Initiation in region Growth 60 min Time Interval

33. Bias vs. POD for ALL Initiation/Growth Cases POD Bias PersistenceANC Forecast Growth/Decay Initiation level 2 Initiation level 1 Extrapolation

34. Different types of initiation PersistenceANC Forecast Growth/Decay Initiation level 2 Initiation level 1 Extrapolation Red : All Cases Yellow : Initiation - line Cyan : Initiation - region Orange : Growth Forecasts for growth show the most skill Initiation of linear storm systems show most improvement over extrapolation Initiation - Line All Growth Initiation- Region POD Bias

35. END THANK YOU !