1. FORECASTING EASTERN US WINTER STORMS Are We Getting Better and Why? Jeff S. Waldstreicher NOAA/NWS Eastern Region Scientific Services Division – Bohemia, NY Northeast Regional Operational Workshop (NROW) November 4, 2004

2. OUTLINE Winter Storm Warning Program Winter Storm Warning Program Verification Review Verification Review Key Activities and Developments Key Activities and Developments Relationship Between Event Totals and Warning Performance Relationship Between Event Totals and Warning Performance Summary Summary

3. MOTIVATION Winter of 2003-2004 Performance Winter of 2003-2004 Performance EASTERN REGION WIDE EASTERN REGION WIDE POD -.921 POD -.921 FAR -.321 FAR -.321 Lead Time – 18.5 hours Lead Time – 18.5 hours NORTHEAST NORTHEAST POD -.920 POD -.920 FAR -.321 FAR -.321 Lead Time – 20.3 hours Lead Time – 20.3 hours Is this indicative of a positive performance trend? Is this indicative of a positive performance trend? If yes, what are the contributing factors? If yes, what are the contributing factors?

6. WINTER STORM WARNING VERIFICATION RESULTS 1993-94 to 2003-04

11. NORTHEAST POD

12. NORTHEAST FAR

13. NORTHEAST LEAD TIME

14. KEY ACTIVITIES AND DEVELOPMENTS RELATED TO FORECASTING WINTER STORMS 1993-2004

15. NWP ADVANCES Global Model Global Model 1993 – AVN/MRF at T126/L28 1993 – AVN/MRF at T126/L28 2/day AVN to 126h and 1/day MRF to 240h 2/day AVN to 126h and 1/day MRF to 240h 2004 – GFS at T256/L64 to 84 h 2004 – GFS at T256/L64 to 84 h 4/day to 384h (T170/L42 84-180h T126/L28 to 386h) 4/day to 384h (T170/L42 84-180h T126/L28 to 386h) Numerous improvements to physics, data assimilation etc… Numerous improvements to physics, data assimilation etc… Medium Range Ensemble Forecast System (MREF) Medium Range Ensemble Forecast System (MREF) ~1997 – 1/day 12 member system ~1997 – 1/day 12 member system 2004 – 4/day 48 member system including lag members 2004 – 4/day 48 member system including lag members NGM – Static Since 1993 NGM – Static Since 1993

16. NWP ADVANCES Eta (NAM) Eta (NAM) 1993 – Early Eta 80 km / 38 levels / 00 and 12Z / 48h 1993 – Early Eta 80 km / 38 levels / 00 and 12Z / 48h 1995 – Meso Eta 32 km / 50 levels / 03 and 15Z / 33h 1995 – Meso Eta 32 km / 50 levels / 03 and 15Z / 33h 2004 – MesoEta 12 km / 60 levels / 4 x day / 84 hr 2004 – MesoEta 12 km / 60 levels / 4 x day / 84 hr Numerous improvements to physics, data assimilation etc… Numerous improvements to physics, data assimilation etc… Local Area Modeling - Workstation Eta Local Area Modeling - Workstation Eta Short Range Ensemble Forecast System (SREF) Short Range Ensemble Forecast System (SREF) ~1999 – 10 members (5 48 km Eta / 5 RSM) ~1999 – 10 members (5 48 km Eta / 5 RSM) 2004 – 15 members (10- 32 km Eta / 5- 40 km RSM) 2004 – 15 members (10- 32 km Eta / 5- 40 km RSM) Rapid Update Cycle (RUC) Rapid Update Cycle (RUC) ~1994 – RUC1 – 60 km / 25 levels ~1994 – RUC1 – 60 km / 25 levels 1998 – RUC2 – 40 km / 40 levels 1998 – RUC2 – 40 km / 40 levels 2004 – RUC2 – 20 km / 50 levels 2004 – RUC2 – 20 km / 50 levels

17. 1994-1997 WSR-88D Network Installation Completed WSR-88D Network Installation Completed PCGRIDDS/NAWIPS/GARP PCGRIDDS/NAWIPS/GARP Gridded Model Data into Field Offices Gridded Model Data into Field Offices NWS Lake Effect Snow Study NWS Lake Effect Snow Study BUFKIT BUFKIT Expansions of Snow Spotter Networks Expansions of Snow Spotter Networks Expansion of Collaborative Research Projects (COMET) Expansion of Collaborative Research Projects (COMET) First Real-time local model in NWS ER field office (MM5 at BUF and BGM) First Real-time local model in NWS ER field office (MM5 at BUF and BGM)

18. 1998-2000 AWIPS Installations Completed AWIPS Installations Completed Advanced Workstations w/ Integrated Data Sets Advanced Workstations w/ Integrated Data Sets Public Forecast Program Transfers Public Forecast Program Transfers 1998-99 – BGM/CTP start Winter Warning Program 1998-99 – BGM/CTP start Winter Warning Program 1999-00 – AKQ/BTV/CAR/RNK start Winter Warning Program 1999-00 – AKQ/BTV/CAR/RNK start Winter Warning Program Pros – New ideas/techniques, Smaller Forecast Areas Pros – New ideas/techniques, Smaller Forecast Areas Cons – Less experience Cons – Less experience Active Teletraining Program Established Active Teletraining Program Established Web based training modules Web based training modules

19. 1998-2000 Regional Workshops/Conferences Regional Workshops/Conferences Northeast Regional Operational Workshop Northeast Regional Operational Workshop Southern New England Workshop Southern New England Workshop Great Lakes Operational Meteorology Workshop Great Lakes Operational Meteorology Workshop Northeast Storm Conference Northeast Storm Conference Continued Expansion of COMET Projects Continued Expansion of COMET Projects CSTAR Collaborative Research Projects Funded CSTAR Collaborative Research Projects Funded North Carolina State Univ. – WFO Raleigh (early 2000) North Carolina State Univ. – WFO Raleigh (early 2000) State Univ. of New York at Albany – WFO Albany (late 2000) State Univ. of New York at Albany – WFO Albany (late 2000)

20. 2001-2004 Eastern Region Winter Weather Best Practices Team (2001) Eastern Region Winter Weather Best Practices Team (2001) IFPS IFPS Collaborative Forecast Process Collaborative Forecast Process HPC Winter Weather Experiment (WWE) HPC Winter Weather Experiment (WWE) 2001-02 – 4 WFOs (AKQ/LWX/PHI/CTP) 2001-02 – 4 WFOs (AKQ/LWX/PHI/CTP) 2002-03 – All Eastern Region 2002-03 – All Eastern Region 2003-04 – ~75% of CONUS 2003-04 – ~75% of CONUS 2004-05 – Integrated into routine HPC Operations 2004-05 – Integrated into routine HPC Operations Test new collaborative forecast process among HPC and WFOs for winter storm events Test new collaborative forecast process among HPC and WFOs for winter storm events Evaluate new products from SREF Evaluate new products from SREF

21. 2001-2004 Implementation of CSTAR Research Results Implementation of CSTAR Research Results U. at Albany Project U. at Albany Project Mesoscale Banding in Winter Storms Mesoscale Banding in Winter Storms Precipitation Microphysics Precipitation Microphysics Cold Season Closed Lows Cold Season Closed Lows Terrain-Forced Snow Storms Terrain-Forced Snow Storms Impacts of Climate Regimes (ENSO, NAO, etc…) Impacts of Climate Regimes (ENSO, NAO, etc…) N.C. State Project N.C. State Project Cold Air Damming Cold Air Damming Coastal Fronts Coastal Fronts Precipitation Type Forecasting Methodologies Precipitation Type Forecasting Methodologies Regional COMET Projects Regional COMET Projects BTV/McGill Univ. BTV/McGill Univ. OKX/Stony Brook Univ. OKX/Stony Brook Univ.

22. 2001-2004 Weather Event Simulator (WES) – 2001 Weather Event Simulator (WES) – 2001 Training Workstation that can simulate real-time data flow and forecast processes Training Workstation that can simulate real-time data flow and forecast processes AWIPS Archive Server - 2002 AWIPS Archive Server - 2002 Local Capability to archive full AWIPS data sets for WES playback Local Capability to archive full AWIPS data sets for WES playback Expansion of local office training activities and workshops Expansion of local office training activities and workshops

23. 2001-2004 Coming together of several activities and developments: Coming together of several activities and developments: Applied Research and Technique Development Applied Research and Technique Development Technologies Technologies Training Training Operational Application and Procedures Operational Application and Procedures

24. Mesoscale Band Project Timeline

25. RELATIONSHIP BETWEEN EVENT COUNTS AND WARNING PERFORMANCE IMPACTS OF CLIMATE REGIMES?

26. ACTIVE SEASONS IN NORTHEAST >1200 Events Season # of Events PODFAR Lead Time 93-94*1416.923.23011.8 95-961713.842.24614.6 00-011220.913.29618.0 02-031383.916.27716.2 Mean.899.26215.2

27. MODERATE SEASONS IN NORTHEAST 800-1200 Events Season # of Events PODFAR Lead Time 98-991050.890.31413.6 99-001016.902.20112.7 03-041069.920.32120.3 Mean.904.27915.5

28. LAME SEASONS IN NORTHEAST <800 Events Season # of Events PODFAR Lead Time 94-95561.772.46713.6 96-97654.855.53811.3 97-98788.803.48912.8 01-02470.840.40211.7 Mean.818.47412.3

29. MONTHLY NAO/PNA vs. Events Cumulative Winter (Dec-Jan-Feb-Mar) Monthly Mean NAO shows some correlation to number of winter storm events Cumulative Winter (Dec-Jan-Feb-Mar) Monthly Mean NAO shows some correlation to number of winter storm events Cumulative Winter Monthly Mean PNA shows little or no correlation Cumulative Winter Monthly Mean PNA shows little or no correlation Shorter term (daily/weekly) index values likely more important Shorter term (daily/weekly) index values likely more important

30. SUMMARY Winter storm warning performance appears to be improving across the Northeast Winter storm warning performance appears to be improving across the Northeast Greatest improvements in Lead Time Greatest improvements in Lead Time Lead Time improvements are not a result of improved POD Lead Time improvements are not a result of improved POD No increase in false alarms noted No increase in false alarms noted Event totals impact warning performance Event totals impact warning performance More events – better performance More events – better performance Most impact on False Alarms and Lead Time Most impact on False Alarms and Lead Time

31. SUMMARY Performance improvements appear to be related to an evolving “end-to-end” collaborative process of: Discovery and Sharing Discovery and Sharing Demonstration of Added Value (Operational Utility) Demonstration of Added Value (Operational Utility) Operational Implementation Operational Implementation Training Activities Training Activities Periodic Review and Refinement Periodic Review and Refinement