1. AMS 13 th Conference on Aviation, Range and Aerospace Meteorology – January 2008 – New Orleans, Louisiana 1 January 22, 2008 EFFECT OF TAMDAR ON RUC SHORT-TERM FORECASTS OF AVIATION-IMPACT FIELDS FOR CEILING, VISIBILITY, REFLECTIVITY AND PRECIPITATION Ed Szoke*, Stan Benjamin, Randy Collander*, Brian Jamison*, Bill Moninger, Tom Schlatter**, Barry Schwartz and Tracy Smith* NOAA/Earth Systems Research Laboratory Global Systems Division *Joint collaboration with the Cooperative Institute for Research in the Atmosphere, Colorado State University, Fort Collins, CO **Cooperative Institute for Research in Environmental Sciences (CIRES), Boulder, Colorado

2. AMS 13 th Conference on Aviation, Range and Aerospace Meteorology – January 2008 – New Orleans, Louisiana 2 January 22, 2008 Overview TAMDAR soundings have been shown to be useful for forecasting Talks at the last SLS Conference and previous Annual Meetings WFO Green Bay helps maintain the official NOAA TAMDAR web page at http://www.crh.noaa.gov/tamdar/ In this talk we focus on the impact of TAMDAR on short-term NWP: Evaluation of RUC precipitation and visibility/ceiling short-term forecasts for runs with and without TAMDAR No reflectivity comparisons yet; these are coming.... Mostly a subjective evaluation, but objective scoring for 2007 cases Procedure: RUC is run at 20-km horizontal grid resolution Identical runs made hourly to 6 h, and out to 24 h every 3 h Here we will concentrate on shorter term (usually first 6 h to 12 h) forecasts initialized when TAMDAR data is most plentiful 1800 UTC and 0000 UTC initialization times generally used

3. AMS 13 th Conference on Aviation, Range and Aerospace Meteorology – January 2008 – New Orleans, Louisiana 3 January 22, 2008 Flights into a number of smaller airports in addition to the 3 main hubs And at lower altitudes (generally to 20 kft or so) Typical TAMDAR coverage (shown here 1000 UTC/14 Jan – 0400 UTC/15 Jan 08)

4. AMS 13 th Conference on Aviation, Range and Aerospace Meteorology – January 2008 – New Orleans, Louisiana 4 January 22, 2008 Verification areas. Objective scoring is done on both areas, for this study we will show some scores for the inner (blue) box.

5. AMS 13 th Conference on Aviation, Range and Aerospace Meteorology – January 2008 – New Orleans, Louisiana 5 January 22, 2008 Still one of the most dramatic cases...4-5 Oct 2005: heavy precip in the Upper Midwest. Flooding reported in Minnesota to northern Wisconsin. Case 1: 4 October 2005 – 2100 UTC Surface analyses and reflectivity

6. AMS 13 th Conference on Aviation, Range and Aerospace Meteorology – January 2008 – New Orleans, Louisiana 6 January 22, 2008 Very sharp cut off to the precip in WI and a huge gradient with a 2-3” max. NPVU estimated precipitation for 6-h ending 0000 UTC 5 October 2005

7. AMS 13 th Conference on Aviation, Range and Aerospace Meteorology – January 2008 – New Orleans, Louisiana 7 January 22, 2008 Both runs forecast too much precip in southern half of Wisconsin, but the RUC run with TAMDAR correctly forecasts more precip (small spots of >1.00”) across the northern half of the state. RUC forecasts from the 4 October 2005 1800 UTC runs 6-h total precipitation ending 0000 UTC 5 October

8. AMS 13 th Conference on Aviation, Range and Aerospace Meteorology – January 2008 – New Orleans, Louisiana 8 January 22, 2008 Sounding comparison: RUC 6-h forecasts with (labeled dev2) and without (labeled dev1, in black) TAMDAR, compared to the RAOB for Detroit (green) at 0000 UTC 5 Oct 05. Incorrect dry layer in the dev1 forecast.

9. AMS 13 th Conference on Aviation, Range and Aerospace Meteorology – January 2008 – New Orleans, Louisiana 9 January 22, 2008 Same comparison but for Peoria, Illinois. The RUC run with TAMDAR is closer to the RAOB especially at and below 700 mb.

10. AMS 13 th Conference on Aviation, Range and Aerospace Meteorology – January 2008 – New Orleans, Louisiana 10 January 22, 2008 Heavy precip continues in the same areas Case 1/part 2: 5 October 2005 – 0300 UTC Surface analyses and reflectivity

11. AMS 13 th Conference on Aviation, Range and Aerospace Meteorology – January 2008 – New Orleans, Louisiana 11 January 22, 2008 NPVU estimated precipitation for 6-h ending 0600 UTC 5 October 2005

12. AMS 13 th Conference on Aviation, Range and Aerospace Meteorology – January 2008 – New Orleans, Louisiana 12 January 22, 2008 For this period the RUC run that used the TAMDAR data is a much better forecast with a very sharp cut off to the precipitation in Wisconsin and a better location for the heavy precip. RUC forecasts from the 5 October 2005 0000 UTC runs 6-h total precipitation ending 0600 UTC 5 October No TAMDARWith TAMDAR

13. AMS 13 th Conference on Aviation, Range and Aerospace Meteorology – January 2008 – New Orleans, Louisiana 13 January 22, 2008 Case 2: 7 December 2007 – 1200 UTC 500 mb obs and analysis Area of interest: KY/TN Very weak short- wave trough

14. AMS 13 th Conference on Aviation, Range and Aerospace Meteorology – January 2008 – New Orleans, Louisiana 14 January 22, 2008 Case 2: 8 December 2007 0000 UTC 850 mb obs and analysis Area of interest: KY/TN Overrunning situation in place.

15. AMS 13 th Conference on Aviation, Range and Aerospace Meteorology – January 2008 – New Orleans, Louisiana 15 January 22, 2008 Case 2: 7 December 2007 – 1800 UTC Surface obs and reflectivity

16. AMS 13 th Conference on Aviation, Range and Aerospace Meteorology – January 2008 – New Orleans, Louisiana 16 January 22, 2008 Case 2: 7 December 2007 – 2100 UTC Surface obs and reflectivity

17. AMS 13 th Conference on Aviation, Range and Aerospace Meteorology – January 2008 – New Orleans, Louisiana 17 January 22, 2008 Case 2: 8 December 2007 – 0000 UTC Surface obs and reflectivity

18. AMS 13 th Conference on Aviation, Range and Aerospace Meteorology – January 2008 – New Orleans, Louisiana 18 January 22, 2008 NPVU estimated precipitation for 6-h ending 0000 UTC 8 December 2007

19. AMS 13 th Conference on Aviation, Range and Aerospace Meteorology – January 2008 – New Orleans, Louisiana 19 January 22, 2008 3-h accumulated precip forecasts from the 1800 UTC 7 Dec 2007 RUC runs: Without TAMARWith TAMAR 3-h valid at 2100 UTC 6-h valid at 0000 UTC

20. AMS 13 th Conference on Aviation, Range and Aerospace Meteorology – January 2008 – New Orleans, Louisiana 20 January 22, 2008 Sounding comparison between RUC 6-h forecast with (labeled dev2) and without (labeled dev, in black) TAMDAR, compared to the RAOB for Nashville (BNA) for 0000 UTC 8 Dec 07. dev2 is closer to the observed sounding, while dev is too dry, similar to the forecast from the RUC run without TAMDAR.

21. AMS 13 th Conference on Aviation, Range and Aerospace Meteorology – January 2008 – New Orleans, Louisiana 21 January 22, 2008 Did the TAMDAR data lead to a better forecast? Here is a comparison between the two 1800 UTC RUC analysis soundings at Memphis (MEM) compared to some nearby TAMDAR soundings. Note how the analysis from dev2 (RUC with TAMDAR) is more moist than the dev analysis, and compares better to the TAMDAR data.

22. AMS 13 th Conference on Aviation, Range and Aerospace Meteorology – January 2008 – New Orleans, Louisiana 22 January 22, 2008 The SPC severe reports show numerous tornadoes, with some into Southeast Wisconsin (pictures courtesy of Milwaukee/Sullivan, WI WFO). Case 3 - 7-8 January 2008: Unusual January tornado outbreak in the Midwest followed by rain/snow the next day.

23. AMS 13 th Conference on Aviation, Range and Aerospace Meteorology – January 2008 – New Orleans, Louisiana 23 January 22, 2008 This was a strong system with a deep approaching trough at 500 mb. Case 3 - 500 mb analysis and plot for 0000 UTC 8 January 2008

24. AMS 13 th Conference on Aviation, Range and Aerospace Meteorology – January 2008 – New Orleans, Louisiana 24 January 22, 2008 Case 3: 7 January 2008 – 1800 UTC Surface analyses and reflectivity

25. AMS 13 th Conference on Aviation, Range and Aerospace Meteorology – January 2008 – New Orleans, Louisiana 25 January 22, 2008 Case 3: 7 January 2008 – 2100 UTC Surface analyses and reflectivity

26. AMS 13 th Conference on Aviation, Range and Aerospace Meteorology – January 2008 – New Orleans, Louisiana 26 January 22, 2008 Case 3: 8 January 2008 – 0000 UTC Surface analyses and reflectivity

27. AMS 13 th Conference on Aviation, Range and Aerospace Meteorology – January 2008 – New Orleans, Louisiana 27 January 22, 2008 NPVU estimated precipitation for 6-h ending 0000 UTC 8 January 2008

28. AMS 13 th Conference on Aviation, Range and Aerospace Meteorology – January 2008 – New Orleans, Louisiana 28 January 22, 2008 Mixed verification: The RUC run with TAMDAR verifies better in northern Illinois (blue circle), but not as good as the run without TAMDAR in northern Wisconsin (red circle). RUC forecasts from the 8 January 2008 1800 UTC runs 6-h total precipitation ending 0000 UTC 9 January

29. AMS 13 th Conference on Aviation, Range and Aerospace Meteorology – January 2008 – New Orleans, Louisiana 29 January 22, 2008 Case 4: 10 January 2008 – 1800 UTC Surface & 500 mb analyses and reflectivity 2 days after the tornadoes....a modest snowstorm hits the Midwest, with more severe weather south to the Gulf coast

30. AMS 13 th Conference on Aviation, Range and Aerospace Meteorology – January 2008 – New Orleans, Louisiana 30 January 22, 2008 Case 4: 10 January 2008 – Watches and warnings/advisories as of 2200 UTC Prompting the hoisting of Winter Weather Advisories from Iowa to Wisconsin

31. AMS 13 th Conference on Aviation, Range and Aerospace Meteorology – January 2008 – New Orleans, Louisiana 31 January 22, 2008 Case 4: comparison of 18-h accumulated precip forecasts from the 1800 UTC 10 Jan 08 runs In this case we can compare the 18-h accumulated precipitation forecasts to the NPVU 24-h estimate for portions of the Midwest as the precip fell after 1800 UTC 10 Jan. The RUC run with TAMDAR has more precip in Wisconsin, which verifies better. RUC without TAMDAR RUC with TAMDAR

32. AMS 13 th Conference on Aviation, Range and Aerospace Meteorology – January 2008 – New Orleans, Louisiana 32 January 22, 2008 Case 4: comparison of 18-h accumulated precip forecasts from the 1800 UTC 10 Jan 08 runs Here is the comparison of the 18-h accumulated snowfall forecasts to the 24-h snow reports. A forecast of more snow in Wisconsin is better. RUC without TAMDAR RUC with TAMDAR

33. AMS 13 th Conference on Aviation, Range and Aerospace Meteorology – January 2008 – New Orleans, Louisiana 33 January 22, 2008 Case 5: 21 December 2007 – the Midwest in a pre-Christmas fog. 21z with vis image.

34. AMS 13 th Conference on Aviation, Range and Aerospace Meteorology – January 2008 – New Orleans, Louisiana 34 January 22, 2008 White shading is for a forecast of visibility at or below 1 mile Some differences are seen – these are outlined in the forecasts; similar differences were found in the 6-h forecasts valid at 0000 UTC. Verification: The RUC forecast that uses TAMDAR is better along the WI/MN border but worse in WI, where more dense fog is a better forecast. RUC 3-h forecasts of visibility from the 21 December 2007 1800 UTC runs valid 2100 UTC 21 December Without TAMDAR With TAMDAR

35. AMS 13 th Conference on Aviation, Range and Aerospace Meteorology – January 2008 – New Orleans, Louisiana 35 January 22, 2008 Case 5: 21 December 2007 – WI/MN/IA closeup for 2100 UTC.

36. AMS 13 th Conference on Aviation, Range and Aerospace Meteorology – January 2008 – New Orleans, Louisiana 36 January 22, 2008 TAMDAR coverage for the period 1500 to 1800 UTC on 21 December 2007 One reason for less improvement with the TAMDAR run might have been because of flights canceled by the fog. TAMDAR coverage for the period 1500 to 1800 UTC on 7 December 2007 when conditions were better.

37. AMS 13 th Conference on Aviation, Range and Aerospace Meteorology – January 2008 – New Orleans, Louisiana 37 January 22, 2008 Case 6: 8 January 2008 – more Midwest fog; 0600 UTC cig and vis plot from AWIPS. Visibilities under a mile cover pretty much all of Wisconsin

38. AMS 13 th Conference on Aviation, Range and Aerospace Meteorology – January 2008 – New Orleans, Louisiana 38 January 22, 2008 White shading is for a forecast of visibility below 1 mile Main differences are found in eastern Wisconsin Verification: The RUC forecast that uses TAMDAR is better in eastern WI where more fog is the better forecast. RUC 6-h forecasts of visibility from the 8 January 2008 0000 UTC runs valid 0600 UTC 8 January Without TAMDARWith TAMDAR

39. AMS 13 th Conference on Aviation, Range and Aerospace Meteorology – January 2008 – New Orleans, Louisiana 39 January 22, 2008 Only small differences between the forecasts, in southern Wisconsin. Often many cases had just small differences between the RUC forecasts. Verification: There is nothing in the observations to support the sliver of higher CIGS found in the forecast without TAMDAR RUC 6-h forecasts of ceiling from the 8 January 2008 0000 UTC runs valid 0600 UTC 8 January Without TAMDARWith TAMDAR ceiling height AGL x1000 feet

40. AMS 13 th Conference on Aviation, Range and Aerospace Meteorology – January 2008 – New Orleans, Louisiana 40 January 22, 2008 Statistics (CSI) for the period 20 Nov 2007 – 15 Jan 2008 for LIFR conditions (vis < 1 mile and/or cig < 500 ft AGL) from the 1800 UTC runs. 6-h forecasts from the 1800 RUC runs with (“dev2”) and without (“dev”) TAMDAR. Difference plot is positive when dev2 is better than dev. Yellow vertical line denotes case day shown earlier. No real trend for better performance with TAMDAR for this period and forecast cycle.

41. AMS 13 th Conference on Aviation, Range and Aerospace Meteorology – January 2008 – New Orleans, Louisiana 41 January 22, 2008 Statistics (CSI) for the period 20 Nov 2007 – 15 Jan 2008 for LIFR conditions (vis < 1 mile and/or cig < 500 ft AGL) from the 0000 UTC runs. 6-h forecasts from the 0000 RUC runs with (“dev2”) and without (“dev”) TAMDAR. Difference plot is positive when dev2 is better than dev. Yellow vertical line denotes case day shown earlier. Again, no real trend for better performance with TAMDAR for this period and forecast cycle.

42. AMS 13 th Conference on Aviation, Range and Aerospace Meteorology – January 2008 – New Orleans, Louisiana 42 January 22, 2008 EQTS numbers that favor the RUC run that uses TAMDAR are highlighted in red. Most scores are close or slightly favor the run with TAMDAR, especially the 6-h forecasts from the 1800 UTC runs. Objective scores for the two RUC forecasts for the small verification area

43. AMS 13 th Conference on Aviation, Range and Aerospace Meteorology – January 2008 – New Orleans, Louisiana 43 January 22, 2008 Summary One of the earliest precipitation forecasts examined (the 4-5 October 2005 case) remains the most impressive one we've seen in terms of significantly better forecasts by the RUC run that used TAMDAR More typically, we see much smaller impacts These tend to favor the RUC run that uses TAMDAR, but not always And sometimes mixed...forecast better in some spots but not in others Objective scoring of the precipitation forecasts that began in 2007 agrees with our overall subjective impression But on a case by case basis can see differences in the scores Ceiling and visibility forecasts generally behave like what we have seen with precipitation Usually mixed verification...sometimes within the same forecast time.