1 Results from Winter Storm Reconnaissance Program 2008 Yucheng SongIMSG/EMC/NCEP Zoltan TothEMC/NCEP/NWS Sharan MajumdarUniv. of Miami Mark ShirleyNCO/NCEP/NWS

2 Acknowledgments NWS field offices, HPC/NCEP and SDMs NOAA P-3 and the USAFR C-130 flight crews CARCAH (John Pavone) Jack Woollen - EMC Russ Treadon - EMC Mark Iredell - EMC Istvan Szunyogh – Univ. of Maryland Craig Bishop - NRL + others who have contributed!

Winter Storm Reconnaissance Program Objective: Improve Forecasts of Significant Winter Weather Events Through Targeted Observations in Data Sparse Northeast Pacific Ocean Adaptive approach to collection of observational data: 1) Only Prior to Significant Winter Weather Events of Interest 2) Only in Areas that Influence high impact event Forecasts Past Results: 70+% of Targeted Numerical Weather Predictions Improve 10-20% error reduction for high impact event forecasts 12-hour gain in predicting high impact events – earlier warnings possible Operational since January 2001

4 Valentine’s day Storm Weather event with a large societal impact Each GFS run verified against its own analysis – 60 hr forecast Impact on surface pressure verification RMS error improvement: 19.7% (2.48mb vs. 2.97mb) Targeted in high impact weather area marked by the circle Surface pressure from analysis (hPa; solid contours) Forecast Improvement (hPa; shown in red) Forecast Degradation (hPa; blue)

5 The ETKF spotted the target area Expected error reduction propagation Targeting methods – ETKF (application example) Storm Dropsondes to be made by An Aircraft How NCEP WSR program works

6 About the Winter Storm Reconnaissance (WSR 2008) Program Took place 17 Jan – 15 March 2008 Dropwinsonde observations taken over the NE Pacific by aircraft operated by NOAA’s Aircraft Operations Center (P-3) and the US Air Force Reserve (C-130s). Observations are adaptive – –collected only prior to significant winter weather events of interest –in areas that might influence forecast the most. 35 good flights, around 629 dropsondes this winter due to the joint interests from HMT G-IV was not available due to installation

7 WSR 2008 – New Tracks for P-3 More ensemble members, efficient ET KF codes No G-IV due to new instrument installation New tracks for NOAA P-3 flying out of Portland, OR

8 Winter Storm Reconnaissance (WSR 2008) Program – Verification Experiment Design - Global parallel NCEP GFS experiments –NCEP Global Forecast System running on T126L64 resolution hybrid-sigma with GSI vs. T12628 in the past –Three sets of experiments A. GFS run with WSR dropsondes being assimilated B. GFS run with WSR dropsondes data rejected on all days Evaluation methods –Impact: compare differences between the paired runs –Forecast improvement: compare forecast fit to its own analysis –Fit to observations: spatially averaged over the verification regions

9 VERIFICATION A Special HMT/WSR case Verification statistics

10 A special HMT mission Feb 24 00Z, 2008 Large forecast uncertainties (blue regions) on Feb 22 and Feb 23, 2008 Relative measure of predictability

11 A special HMT/WSR mission ( Atmospheric River, Feb 24, 00Z, 2008)

12 A HMT/WSR Mission (Surface PWAT)

13 Impact of the Dropsondes Signal Propagation (250mb Height) Forecast improvement (Surface pressure)

14 Comparison of ETKF signal and NCEP signal (Remarkable resemblance) The ETKF signalThe NCEP signal

15 Comparison of ETKF signal and NCEP signal ( Flight track 54, Feb 24 00Z 2008 )

16 A special HMT/WSR mission (Observed Precipitation)

17 Forecast Verification for Surface pressure (2008) RMS error reduction vs. forecast lead time

18 Forecast Verification for Wind (2008) RMS error reduction vs. forecast lead time

19 Forecast Verification for Temperature (2008) RMS error reduction vs. forecast lead time

20 Overall results for Temperature (2007 vs. 2008)

21 Overall results for Vector wind The RMS error reduction could reach as high as 30% in certain verification areas in 2007

22 Overall results for Surface pressure (2007 vs. 2008)

23 Overall results for Humidity (2007 vs. 2008)

24 Due to the lack of G-IV, 2008 is not an impressive year from verification results P-3 tracks are close to inland (Portland, OR) - less likely the data would have a big impact C-130 flying lower compared to G-IV Upper level wind may be important, especially in the Jet regions – bode well for DWL measurement? Summary

25 WSR Summary statistics ( ) Variable # cases improved # cases neutral #cases degraded Surface pressure = = =49 Temperature = = =40 Vector Wind = = =38 Humidity = = = = 92 OVERALL POSITIVE CASES = 1 OVERALL NEUTRAL CASES = 36 OVERALL NEGATIVE CASES. 71.3% improved 27.9% degraded

26 Winter Storm Damages can’t be underestimated

27 Composite summary maps 139.6W 59.8N 36hrs (7 cases) km92W 38.6N 60hrs (5 cases)- 4064km 122W 37.5N 49.5hrs (8 cases) km 80W 38.6N 63.5hrs (8 cases) km Verification Region

28 ETKF predicted signal propagation

29 Precipitation verification Precipitation verification is still in a testing stage due to the lack of station observation data in some regions OPR CTL 3:14:1 Positive vs. negative cases 10mm5mmETS