1. Recent Forecast Impact Results from WSR and ATREC
Lacey Holland SAIC/EMC/NCEP (now NCAR)
Zoltan Toth EMC/NCEP/NWS
Sharan Majumdar Univ. Miami
Yucheng Song IMSG/EMC/NCEP
Lidar workshop, Sedona, Arizona

2. Acknowledgements NWS field offices, HPC/NCEP and SDMs
NOAA G-IV and the USAFR C-130 flight crews
Roy Smith (NCO/NCEP/NWS)
CARCAH (John Pavone)
Jack Woollen - EMC
Russ Treadon - EMC
Mark Iredell - EMC
Istvan Szunyogh – Univ. of Maryland
Craig Bishop - NRL
+ others who have contributed!

3. About the A-TReC 15 October – 17 December 2003
Observing platforms: AMDAR, ASAP ships, GOES rapid-scan winds, extra radiosondes, aircraft (DLR Falcon, USAF C-130, NOAA G-IV, UND Citation)
Observations were selected using a variety of adaptive observing strategies run daily in USA and Europe (ETKF, total energy singular vectors, Hessian singular vectors, adjoint)

4. A-TReC Case 23
Top: ETKF summary map and signal variance evolution Bottom: ECMWF TESV summary

5. Results for Surface Pressure
Of all cases:
35 improved
2 neutral
10 degraded
These are verified over the “WSR”-like 1000 km verification disk as the calculations were performed over

6. Evaluation methodology
Compare analysis and forecast cycles from the GFS at T126L28 resolution including all operationally available data (includes dropsondes); the other excludes only dropsonde data - to evaluate the data impact
Verify against observations over the pre-selected area of interest (verification region)
Rawinsonde observations for surface pressure, hPa temperature, and other fields
Rain gauge data for precipitation

7. Results for Temperature
Of all cases:
42 improved
0 neutral
5 degraded

8. Results for Vector Wind
Of all cases:
37 improved
0 neutral
10 degraded

9. Results for Humidity
Of all cases:
43 improved
0 neutral
4 degraded

10. Breakdown for cases Variable # cases improved # cases neutral
#cases degraded
Surface pressure 35 2 10
Temperature 42 5
Vector Wind 37
Humidity 43 4

11. Individual Case Comparison
CASE P, T, V, Q, OVERALL
39 OVERALL POSITIVE CASES.
6 OVERALL NEUTRAL CASES.
2 OVERALL NEGATIVE CASES.
83% improved
13% neutral
4% degraded
OVERALL EFFECT:
Impact/fcstimprv graphics and verification stats soon to appear on web – still filling in a few ‘holes’ for the graphics; planning also for an explanatory write-up about our graphics for everyone’s reference.
1 denotes positive effect
0 denotes neutral effect
-1 denotes negative effect

12. About the Winter Storm Reconnaissance (WSR) Program
Took place 21 Jan – 17 March 2004
Dropwinsonde observations taken over the NE Pacific by aircraft operated by NOAA’s Aircraft Operations Center (G-IV) and the US Air Force Reserve (C-130s).
Observations are adaptively deployed using Ensemble Transform Kalman Filter (ETKF) –
collected only prior to significant winter weather events of interest
in areas expected to influence the forecast the most.
Previous forecasts improved in 60-80% of targeted cases (in past studies)
Operational since January 2001
36 flights, around 720 dropsondes this winter

13. ETKF Signal Variance ETKF “Summary Map” Observation time: 2004022300
Verification time:
Latitude: 32N Longitude: 85W
Priority: HIGH
Comments: Heavy rain in
eastern TX/OK thru north FL.
Verification time:
Latitude: 35N Longitude: 120W
Comments: Heavy rain So/Ce CA.
ETKF Signal Variance
ETKF “Summary Map”

14. Influence of WSR dropwindsonde observations from Flight Track #31 on NCEP GFS forecasts, initialized

15. Results for Surface Pressure
Of the cases:
21 improved
1 neutral
13 degraded

16. Results for Temperature
Of the cases:
21 improved
1 neutral
13 degraded

17. Results for Vector Wind
Of all cases:
24 improved
1 neutral
10 degraded

18. Results for Specific Humidity
Of all cases:
21 improved
0 neutral
14 degraded

19. Breakdown for cases Variable # cases improved # cases neutral
#cases degraded
Surface pressure 21 1 13
Temperature
Vector Wind 24 10
Humidity 14

20. Individual Case Comparison
OBS. DATE P, T, V, OVERALL
1 denotes positive effect
0 denotes neutral effect
-1 denotes negative effect
24 OVERALL POSITIVE CASES.
0 OVERALL NEUTRAL CASES.
11 OVERALL NEGATIVE CASES.
69% improved
31% degraded
OVERALL EFFECT:

21. WSR05 improvement
Increased ensemble member number to 68 from 39 for the ETKF perturbation calculation
Better coding structure
The C130s will be based in Anchorage, while the G-IV will be based in Honolulu.

23. Future Work Examine the effects of dropsondes on precipitation
Compute average improvement / degradation over WSR domain (NE Pacific, U.S.)
Improve targeting method by reducing spurious or misleading guidance due to statistical sampling problems
Evaluate NCEP Atlantic Winter Storm results
Evaluate WSR using ensembles for WSR05
Increase resolution and ensemble membership for WSR06
Increased duration of program for WSR06?