1. AMPS 10km MM5 Operational Evaluation of Cloud Base/Ceiling Product Bryan M. Burden Aviation Technical Services SPAWARSYSCEN, Charleston

2. Is There a Need? Is There a Need? n Flights Affected n Accuracy Component n Reliability

3. Forecaster Comments Forecaster Comments n Comments Good n Comments Bad “Good With Major Systems” “Solid Performer In Good Weather” Weather” “More Accurate over Polar Plateau” Plateau” “Under Forecast Amounts” “Limited Low Clouds Reflected” “Underestimated Low Clouds”

4. Cloud Base Evaluation Cloud Base Evaluation n Positive & Negative Aspects n Help to the Forecaster n Add to the Process

5. Where the Data Came From Where the Data Came From n AMPS Model Data n Corresponding Observations n Ice Runway McMurdo

6. Compiling Data n 60 Model Runs n 1800 Model Hours n Product Output Compared to Actual Observations

7. Parameters Used Parameters Used n Basic Designators FEW, SCT, BKN, OVC n Model Output Given Ceiling Designators n Ceiling Designator Used from Real-Time Observations n More Emphasis Given to Ceilings

8. Criteria n Ceilings Did Or Did Not Match n Accurate When Ceiling Output < 3,000ft and Within 1,000ft Of Actual n Accurate When Ceiling Output 3,000ft and Greater Within 5,000ft Of Actual

9. Limitations n Limited Sample Size Short Duration Nov-Dec 2003 Short Duration Nov-Dec 2003 One Location Used Ice Runway (NZIR) One Location Used Ice Runway (NZIR)

10. First Focus n High Ceiling on Output n Actual Ceiling Much Lower n 5 Times Ceiling Forecast n 4 Times Significantly Lower

11. Advancing Low Pressure System Moving In From the South and West Across the Ross Ice Shelf Synoptic Pattern

12. Model FEW050 FEW080 BKN100 Actual Actual SCT100 BKN200 SCT100 BKN200

13. Model Model FEW050 FEW080 SCT100 Actual Actual SCT006 BKN012 OVC140 SCT006 BKN012 OVC140

14. Model Model SCT020 BKN030 OVC060 Actual Actual FEW030 FEW065 SCT150 FEW030 FEW065 SCT150

15. Summary n Model Output Bias Towards Higher Cloud Heights n Lower Clouds 80% of the Time Missed or Under Forecast by Model Output

16. Timing Issues n Too Fast to Clear n Model Adjusted but too Late n 4 Times Occurred n 2 Times Missed

17. Exiting Low Pressure System Moving Away To The North and East Over Open Ocean Water Synoptic Pattern

18. Model Model FEW060 BKN100 FEW060 BKN100 Actual Actual FEW012 BKN035 BKN075 FEW012 BKN035 BKN075

19. Summary n Clouds Become Trapped In Terrain n Model’s Bias Toward Clearing too Quickly n Timing too Fast for Actual Occurrences n 50% of the Time Not Accurate/Accurate

20. Fork In The Road

21. Good Forecast Output Good Forecast Output n Generally Good Weather Good Output n Higher the Ceiling the More Accurate n Rates Accurate to Near 80%

22. High Pressure Ridge Strengthening Ridge at All Levels Of The Atmosphere Synoptic Pattern

23. Model Model FEW160 FEW160 Actual Actual FEW140 FEW180 FEW140 FEW180

24. Summary n Solid Output During Quiet Weather n 80% Accuracy Between Systems n The Better The Weather, The Better The Output

25. Conclusions n Objective Evaluation Conducted With Limited Data and Small Parameters n Get Better Numbers In Open Terrain? n More Analysis Needed n Continue to Fine Tune Model Output

26. Questions ? ? ?