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The 17 Feb 2006 Severe Weather and High Wind Event across Eastern New York and New England

The 17 Feb 2006 Severe Weather and High Wind Event across Eastern New York and New England. Thomas A. Wasula and Neil A. Stuart NOAA/NWS at Albany Alicia C. Wasula SUNY/University at Albany Northeast Regional Workshop 8 November 1-2, 2006. Motivation.

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The 17 Feb 2006 Severe Weather and High Wind Event across Eastern New York and New England

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  1. The 17 Feb 2006 Severe Weather and High Wind Event across Eastern New York and New England Thomas A. Wasula and Neil A. Stuart NOAA/NWS at Albany Alicia C. Wasula SUNY/University at Albany Northeast Regional Workshop 8 November 1-2, 2006

  2. Motivation • Cool season severe weather events are very uncommon in the Northeast (very few events in February) • To understand why the severe weather occurred in the morning of this case study and what caused the anomalous high wind event • To test the hypothesis that the line of severe convection was a Narrow Cold Frontal Rainband (Strongly Forced High Shear-Low Instability Convective Line)

  3. Data • Thunderstorm Day data from NCDC • Observational surface and upper air data • Anomaly plots based on the NCEP/NCAR Global Reanalysis Dataset (1960-1990 21-day mean) • LAPS and MSAS Hourly data • NAM12 model data • Satellite/Water Vapor and Lightning data • KENX 8-bit radar data

  4. Albany has only ~6 in over 60 yrs in FEB ! Albany Averages 24 T-storm Days/Year Data Source: NCDC

  5. Background on 17 FEB 2006 Event • Severe weather ahead of cold front not well anticipated (High wind event was well anticipated) • 12+ severe weather events from bowing segments in narrow cold frontal rain band • Much of eastern New York in left front quadrant of mid- and upper-level jet streaks • Powerful shortwave trough and arctic front were lifting mechanisms

  6. High Wind Event 2/17/06 • National Grid reported 100,000+ customers out of power in eastern New York. Saratoga and Warren Counties were hit especially hard (i.e. Saratoga Springs significant tree and utility pole damage) • Post-frontal wind gusts of 60 to 85 mph were common • Infamous gust to 143 mph atop Stratton mountain (3885 ft) in southern VT • Wind gusts and widespread damage similar to July 15,1995 and the Labor Day 1998 Derechoes

  7. Mosaic Radar Loop 12Z-1930Z 17 FEB 2006 www.spc.noaa.gov

  8. Severe Weather 17 February 2006 16 FEB reports 57 hail 40 wind 1 tornado www.spc.noaa.gov

  9. Thanks to John Quinlan for this slide

  10. 1200Z 17 FEB 2006 Surface Map Albany Forecast Area in warm sector (Sfc temps~10°C and dewpoints ~5°C)

  11. 1200 UTC 17 FEB 2006 500 hPa Heights, Isotachs and Temps www.spc.noaa.gov

  12. 1200 UTC 17 FEB 2006 300 hPa Heights, Isotachs and Temps

  13. 1200 UTC 17 FEB 2006 850 hPa Heights, Isotachs and Temps

  14. 12Z 17 FEB 2006 Low Level Standardized Anomalies (vs. 1960-1990 climo.)

  15. 12Z 17 FEB 2006 850 hPa U and V Standardized Anomalies

  16. SPC Severe Weather Outlooks This event was extremely challenging on all levels !!! 1300Z 17 FEB 2006 1630Z 17 FEB 2006

  17. Severe Weather Composite (700-500 mb lapse rates) Little SBCAPE to work with…but steep mid level lapse rates (based on RUC from SPC)

  18. 1200 UTC 17 FEB 2006Albany Sounding Unidirectional 300-850 hPa flow ***12Z BUF Sounding FROPA with MLCAPE < 50 J kg-1 and 0-6 km shear 89 kts***

  19. 1415Z Water Vapor Image Convective initiation occurs in clear slot behind pre-frontal trough

  20. 1445Z Visible Satellite Picture and 15 Min LTG Clearing ahead of cold front.

  21. 12Z NAM12 0-6 km Bulk Shear and 0-10 km MUCAPE for 15Z 17 FEB 2006 0-6 km Bulk Shear values 65-85 knots MUCAPE < 100 J kg-1

  22. 12Z NAM12 F1500Z Cross-section down the Hudson River Valley (Omega, Theta-e and Winds) White arrow indicates weak convective instability (theta-e decreasing with height)

  23. 16Z KPOU LAPS Sounding

  24. 16Z LAPS SBCAPE and Lifted Indices SBCAPE < 200 J kg-1

  25. 16Z MSAS 3-hr MSLP Change 3-hr pressure rises up to 14 hPa

  26. Meteograms: 17/06Z-17/18Z G48 G40 G40 G52 G52 G44 G42 G42 TEMP (F) DWPT (F) PMSL SYR ALB

  27. 17 FEB 2006 KENX Severe Weather Radar Highlights

  28. 1320Z 0.5° KENX Reflectivity ALY Approaching developing line of convection with the cold front. Prefrontal trough showery activity helps moisten the boundary layer.

  29. 1400Z 0.5° KENX Reflectivity Convective line more organized… no lightning yet !

  30. 1453Z KENX Base Reflectivity Bow Echo develops and first warning issued at 1454Z.

  31. 1459Z 0.5° KENX REF and Velocity Significant BowEcho Shallow mesocyclone develops N/NE of RDA. Roof blown off home in Edinburgh with northern bow. Southern bow had 62kt gust. Saratoga County velocity values > 55 knots at 3.3-5.3kft AGL

  32. 1511Z Base Reflectivity and Velocity Washington County hit hard next with 55-65 kts AGL at 3.5-6.5kft. MESO base and top (5.1; 7.5kft)

  33. 1510Z Composite Reflectivity Cross-section (Penny Size Hail) 45 dBz to ~10kft!

  34. 1516Z KENX VIL and 15 min LTG VIL 15 kg m2

  35. 1534Z 0.5° KENX Reflectivity and Velocity Squall line passed east of ALY with winds 65-75kts 2-3kft AGL Winds 80-100 kts 3.5-5kft AGL. KDDH 57kt gust.

  36. 1545Z KENX Echo Tops ETs 15-20kft

  37. Preliminary Results • Highly anomalous February severe weather event in Northeast US • 925/850 hPa wind anomalies of +/- 2-3  • Low CAPE/high shear environment • Convective initiation occurs in clear slot behind pre-frontal trough after PBL is moistened • Narrow cold-frontal rainband results from strongly forced linear convective line

  38. Future Work • Frontogenesis calculations at surface, 925, 850 hPa • Develop climatology of cool season severe weather events in Northeast US to improve forecaster recognition 24+ hours in advance

  39. Acknowledgements • John Quinlan (GIS Wind Damage slide) • Rich Grumm (Anomaly slides of the event) • Warren Snyder (WES upgrade and case download) • Robert Tracey (SUNYA undergrad) for his help with the radar loop

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