1 Results from Winter Storm Reconnaissance Program 2007 Yucheng SongIMSG/EMC/NCEP Zoltan TothEMC/NCEP/NWS Sharan MajumdarUniv. of Miami Mark ShirleyNCO/NCEP/NWS Meeting of the Working Group on Space-based Lidar Winds, Monterey, CA 5-8 Feburary 2008

2 Winter Storm Damages can’t be underestimated

3 Acknowledgments NWS field offices, HPC/NCEP and SDMs NOAA G-IV 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 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

5 About the Winter Storm Reconnaissance (WSR 2007) Program Took place 20 Jan – 13 March 2007 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 adaptive – –collected only prior to significant winter weather events of interest –in areas that might influence forecast the most. 31 flights, around 478 dropsondes this winter which is increased from 342 drops last year Several communication problems from C-130s

6 About the Winter Storm Reconnaissance (WSR 2007) Program – (continued) Evaluation methods –NCEP Global Forecast System running on T126L28 resolution –Three sets of experiments A. GFS run with all the WSR dropsondes being assimilated B. GFS run without WSR dropsondes data rejected on all days C. GFS run with WSR dropsondes data rejected only on the WSR observation day (i.e. the guess files are the same as the operational) Experiment Design - Experiment C is used for signal propagation studies, it can single out the data impact due to current dropsondes clearly without interferences from the previous dropsondes

7 The ETKF spotted the target area Expected error reduction propagation Targeting methods – ETKF application example Storm Dropsondes to be made by G-IV

8 Forecast verification (Jan 20-22,2007 A vs.C ) Red contours show forecast improvement due to WSR dropsondes, blue contours show forecast degradation 500mb height 250mb height Sea Level Pressure

9 Impact of Dropsondes 500mb height 250mb height Precipitation Surface pressure Contours are 1000mb geopotential height, shades are differences in the fields between two experiments

10 Comparison of ETKF signal and NCEP signal (A vs. C) The ETKF signalThe NCEP signal

11 Valentine’s day storm 2007 One of the largest winter storms that strikes interior sections of the Northeast since 1950

12 NCEP requested two missions A flight is requested from Honolulu along track 34 with a control time of 11/00Z Verification information is as follows: Verification time: Latitude: 36 Longitude: 86 Priority: HIGH Comments: East Coast winter Wx A flight is requested from Honolulu along track 46 with a control time of 12/00Z Verification information is as follows: Verification time: Latitude: 38 Longitude: 77 Priority: HIGH Comments: East Coast winter wx

13 Comparison of ETKF signal and NCEP signal

14 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) Surface pressure from analysis (hPa; solid contours) Forecast Improvement (hPa; shown in red) Forecast Degradation (hPa; blue)

15 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) Surface pressure from analysis (hPa; solid contours) Forecast Improvement (hPa; shown in red) Forecast Degradation (hPa; blue)

16 Valentine’s day Storm Impact on precipitation ( A.vs.C )

17 Forecast Verification for Wind (2007) RMS error reduction vs. forecast lead time 10-20% rms error reduction in winds

18 Forecast Verification for Temperature (2007) RMS error reduction vs. forecast lead time 10-20% rms error reduction in Temperature 60 hr forecast is equivalent to 48hr forecast

19 Breakdown for cases Variable # cases improved # cases neutral #cases degraded Surface pressure Temperature Vector Wind Humidity

20 Individual Case Comparison 1 denotes positive effect 0 denotes neutral effect -1 denotes negative effect 26 OVERALL POSITIVE 0 OVERALL NEUTRAL 11 OVERALL NEGATIVE 70% improved 30 % degraded VR OBSDATE P T V OVERALL REGION FHOUR AK W,55N 48 C W,33N 72 W W,40N 48 W W,40N 24 W W,38N 24 W W,32N 48 E W,36N 72 W W,32N 36 E W,38N 60 W W,45N 24 AK W,60N 48 W W,40N 36 W W,40N 24 C W,37N 48 C W,35N 72 W W,40N 60 W W,40N 36 C W,43N 72 C W,40N 96 W W,37N 24 C W,40N 72 E W,36N 96 W W,42N 48 C W,37N 48 W W,42N 48 W W,42N 24 W W,43N 36 E W,35N 48 W W,49N 36 AK W,55N 36 E W,34N 108 W W,46N 60 W W,45N 72 C W,37N 48 C W,32N 36 E W,42N 96 E W,42N 48

21 Overall results for Surface pressure Of all cases: 25 improved 0 neutral 12 degraded

22 Overall results for Temperature Of all cases: 24 improved 0 neutral 13 degraded

23 Overall results for Vector wind Of all cases: 27 improved 0 neutral 10 degraded

24 Overall results for Humidity Of all cases: 24 improved 0 neutral 13 degraded

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 WSR 2008 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

27 Background Slides

28 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

29 ETKF predicted signal propagation

30 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