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Recurving Typhoons as Precursors to an Early Season Arctic Outbreak over the Continental U.S.

Recurving Typhoons as Precursors to an Early Season Arctic Outbreak over the Continental U.S. Heather M. Archambault, Lance F. Bosart, and Daniel Keyser. Dept. of Earth and Atmospheric Sciences University at Albany, State University of New York. NSF Grant ATM-0434189. NROW IX.

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Recurving Typhoons as Precursors to an Early Season Arctic Outbreak over the Continental U.S.

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  1. Recurving Typhoons as Precursors to an Early Season Arctic Outbreak over the Continental U.S. Heather M. Archambault, Lance F. Bosart, and Daniel Keyser Dept. of Earth and Atmospheric Sciences University at Albany, State University of New York NSF Grant ATM-0434189 NROW IX Wednesday, 7 November 2007 Super Typhoon Oscar, 15 Sep 1995 (Source: NCDC website)

  2. Motivation for Arctic Outbreak Case Study • Document mechanisms linking continental U.S. Arctic outbreak to recurving western North Pacific typhoons (TYs) more than 100° longitude upstream • Relate surface anticyclone associated with Arctic outbreak to surface anticyclone climatological study (Doody 2007)

  3. Overview Impacts of the 20–22 September 1995 Arctic outbreak: • Caused the earliest freeze on record in Chicago, IL • Broke more than 120 U.S. daily record lows • Cut short the growing season across much of the U.S. Plains Surface Temp. < 0°C, Week of 17–23 Sep 1995

  4. 18–22 Sep 1995: Extreme Temperatures 5-d mean 925-hPa temp. anomaly (contoured every 2°C) 5-d mean 925-hPa temp. (contoured every 2°C) • 5-d mean 925-hPa temp. anomalies exceed 8°C over central and northern Plains, and +14°C over northern Alaska and Arctic Ocean

  5. Presentation Outline • Data sources • Key Arctic outbreak mechanisms • W. Pacific TY recurvature and ridge amplification • Pacific–North American downstream development • Western North American blocking • North American surface anticyclogenesis • Summary and conclusions

  6. Data Sources • 2.5° ECMWF ERA-40 reanalysis (sea level pressure (SLP) fields only) • 1.125° ECMWF ERA-40 reanalysis • 2.5° NCEP–NCAR reanalysis 925-hPa temperature and temperature anomaly plots • Constructed at NOAA Earth System Research Laboratory/Physical Science Division website (http://www.cdc.noaa.gov/Composites/Day/) • Japan Meteorological Agency best track plots • Obtained from Digital Typhoon website (http://agora.ex.nii.ac.jp/digital-typhoon/)

  7. 1: TY Recurvature and Ridge Amplification • Three typhoons recurve in the West Pacific within a 7-d period (16–22 Sep 1995) (Klein et al. 2000): • Super Typhoon (STY) Oscar (16 Sep) • TY Polly (19 Sep) • STY Ryan (22 Sep) • Outflow from two of the three recurving TYs (STY Oscar and TY Polly) results in upper-level ridge amplification and jet intensification over the western Pacific (15–20 Sep)

  8. STY Oscar (12–19 Sep 1995) Japan Meteorological Agency Best Track Plot Key:Tropical DepressionWeak Tropical Storm Strong Tropical Storm TyphoonExtratropical Cyclone • Large circles delineate 0000 and 1200 UTC • Small circles delineate 0300, 0600, 0900, 1500, and 2100 UTC

  9. STY Oscar (12–19 Sep 1995) Japan Meteorological Agency Best Track Plot At 30°N, 1200 UTC 16 Sep • 300-hPa vel. potential (contoured every 2  106 m2 s1), irrotational wind (plotted starting at 10 kt) • 925-hPa rel. vorticity (shaded starting at 5  105s1) Key:Tropical DepressionWeak Tropical Storm Strong Tropical Storm TyphoonExtratropical Cyclone • Large circles delineate 0000 and 1200 UTC • Small circles delineate 0300, 0600, 0900, 1500, and 2100 UTC

  10. TY Polly (14–23 Sep 1995) Japan Meteorological Agency Best Track Plot At 30°N, 1200 UTC 20 Sep • 300-hPa vel. potential (contoured every 2  106 m2 s1), irrotational wind (plotted starting at 10 kt) • 925-hPa rel. vorticity (shaded starting at 5  105s1) Key:Tropical DepressionWeak Tropical Storm Strong Tropical Storm TyphoonExtratropical Cyclone • Large circles delineate 0000 and 1200 UTC • Small circles delineate 0300, 0600, 0900, 1500, and 2100 UTC

  11. STY Ryan (15–25 Sep 1995) Japan Meteorological Agency Best Track Plot At 30°N, 1200 UTC 23 Sep • 300-hPa vel. potential (contoured every 2  106 m2 s1), irrotational wind (plotted starting at 10 kt) • 925-hPa rel. vorticity (shaded starting at 5  105s1) Key:Tropical DepressionWeak Tropical Storm Strong Tropical Storm TyphoonExtratropical Cyclone • Large circles delineate 0000 and 1200 UTC • Small circles delineate 0300, 0600, 0900, 1500, and 2100 UTC

  12. Circulation Before TY Recurvature Events 3-d Mean Plot: 12–14 Sep 1995 Oscar Polly 300-hPa streamfunction (thick lines every 10  106 m2 s1) and nondivergent wind speed (shaded every 5 m s1 starting at 35 m s1); SLP (thin lines every 4 hPa)

  13. Circulation During STY Oscar Recurvature 3-d Mean Plot: 15–17 Sep 1995 Oscar Polly Ryan 300-hPa streamfunction (thick lines every 10  106 m2 s1) and nondivergent wind speed (shaded every 5 m s1 starting at 35 m s1); SLP (thin lines every 4 hPa)

  14. Circulation During TY Polly Recurvature 3-d Mean Plot: 18–20 Sep 1995 Oscar Polly Ryan 300-hPa streamfunction (thick lines every 10  106 m2 s1) and nondivergent wind speed (shaded every 5 m s1 starting at 35 m s1); SLP (thin lines every 4 hPa)

  15. 2: Downstream Development • Upper-level ridge amplification results in downstream development across Pacific Ocean and North America (16–22 Sep)

  16. 1200 UTC 16 Sep 1995 300-hPa streamfunction (contoured every 10  106 m2 s1), nondivergent wind (plotted in kt), and meridional nondivergent wind speed (shaded every 10 m s1 according to color bar)

  17. 1200 UTC 18 Sep 1995 300-hPa streamfunction (contoured every 10  106 m2 s1), nondivergent wind (plotted in kt), and meridional nondivergent wind speed (shaded every 10 m s1 according to color bar)

  18. 1200 UTC 20 Sep 1995 300-hPa streamfunction (contoured every 10  106 m2 s1), nondivergent wind (plotted in kt), and meridional nondivergent wind speed (shaded every 10 m s1 according to color bar)

  19. 1200 UTC 22 Sep 1995 300-hPa streamfunction (contoured every 10  106 m2 s1), nondivergent wind (plotted in kt), and meridional nondivergent wind speed (shaded every 10 m s1 according to color bar)

  20. 3: Western North American Blocking • Western North American omega blocking occurs in response to downstream development • Cyclogenesis events in the Gulf of Alaska initiate block onset, maintenance, and “folding over” (anticyclonic wave breaking) (16–22 Sep)

  21. 1200 UTC 16 Sep 1995 1000–500-hPa thickness (dashed every 6 dam), 300-hPa wind speed (shaded every 5 m s1 starting at 45 m s1, and sea level pressure (solid contours every 4 hPa)

  22. 1200 UTC 17 Sep 1995 1000–500-hPa thickness (dashed every 6 dam), 300-hPa wind speed (shaded every 5 m s1 starting at 45 m s1, and sea level pressure (solid contours every 4 hPa)

  23. 1200 UTC 18 Sep 1995 1000–500-hPa thickness (dashed every 6 dam), 300-hPa wind speed (shaded every 5 m s1 starting at 45 m s1, and sea level pressure (solid contours every 4 hPa)

  24. 1200 UTC 19 Sep 1995 1000–500-hPa thickness (dashed every 6 dam), 300-hPa wind speed (shaded every 5 m s1 starting at 45 m s1, and sea level pressure (solid contours every 4 hPa)

  25. 1200 UTC 20 Sep 1995 1000–500-hPa thickness (dashed every 6 dam), 300-hPa wind speed (shaded every 5 m s1 starting at 45 m s1, and sea level pressure (solid contours every 4 hPa)

  26. 1200 UTC 21 Sep 1995 1000–500-hPa thickness (dashed every 6 dam), 300-hPa wind speed (shaded every 5 m s1 starting at 45 m s1, and sea level pressure (solid contours every 4 hPa)

  27. 1200 UTC 22 Sep 1995 1000–500-hPa thickness (dashed every 6 dam), 300-hPa wind speed (shaded every 5 m s1 starting at 45 m s1, and sea level pressure (solid contours every 4 hPa)

  28. 4: North American Surface Anticyclogenesis • Anticyclonic wave breaking results in surface anticyclogenesis over central Canada and initial equatorward movement along the Rockies (18–23 Sep) • Strength and movement of surface anticyclone is associated with advection of anticyclonic geostrophic relative vorticity by the thermal wind (Sutcliffe–Trenberth approximation of quasigeostrophic forcing for vertical motion; Trenberth 1978)

  29. 0000 UTC 18 Sep 1995 H 1000–500-hPa thickness (dashed every 6 dam), 700-hPa geo. relative vorticity (shaded every 3  105 s1 starting at +/ 3  105 s1), and SLP (solid contours every 4 hPa)

  30. 0600 UTC 18 Sep 1995 H 1000–500-hPa thickness (dashed every 6 dam), 700-hPa geo. relative vorticity (shaded every 3  105 s1 starting at +/ 3  105 s1), and SLP (solid contours every 4 hPa)

  31. 1200 UTC 18 Sep 1995 H 1000–500-hPa thickness (dashed every 6 dam), 700-hPa geo. relative vorticity (shaded every 3  105 s1 starting at +/ 3  105 s1), and SLP (solid contours every 4 hPa)

  32. 1800 UTC 18 Sep 1995 H 1000–500-hPa thickness (dashed every 6 dam), 700-hPa geo. relative vorticity (shaded every 3  105 s1 starting at +/ 3  105 s1), and SLP (solid contours every 4 hPa)

  33. 0000 UTC 19 Sep 1995 H 1000–500-hPa thickness (dashed every 6 dam), 700-hPa geo. relative vorticity (shaded every 3  105 s1 starting at +/ 3  105 s1), and SLP (solid contours every 4 hPa)

  34. 0600 UTC 19 Sep 1995 H H 1000–500-hPa thickness (dashed every 6 dam), 700-hPa geo. relative vorticity (shaded every 3  105 s1 starting at +/ 3  105 s1), and SLP (solid contours every 4 hPa)

  35. 1200 UTC 19 Sep 1995 H H 1000–500-hPa thickness (dashed every 6 dam), 700-hPa geo. relative vorticity (shaded every 3  105 s1 starting at +/ 3  105 s1), and SLP (solid contours every 4 hPa)

  36. 1800 UTC 19 Sep 1995 H 1000–500-hPa thickness (dashed every 6 dam), 700-hPa geo. relative vorticity (shaded every 3  105 s1 starting at +/ 3  105 s1), and SLP (solid contours every 4 hPa)

  37. 0000 UTC 20 Sep 1995 H 1000–500-hPa thickness (dashed every 6 dam), 700-hPa geo. relative vorticity (shaded every 3  105 s1 starting at +/ 3  105 s1), and SLP (solid contours every 4 hPa)

  38. 0600 UTC 20 Sep 1995 H 1000–500-hPa thickness (dashed every 6 dam), 700-hPa geo. relative vorticity (shaded every 3  105 s1 starting at +/ 3  105 s1), and SLP (solid contours every 4 hPa)

  39. 1200 UTC 20 Sep 1995 H 1000–500-hPa thickness (dashed every 6 dam), 700-hPa geo. relative vorticity (shaded every 3  105 s1 starting at +/ 3  105 s1), and SLP (solid contours every 4 hPa)

  40. 1800 UTC 20 Sep 1995 H 1000–500-hPa thickness (dashed every 6 dam), 700-hPa geo. relative vorticity (shaded every 3  105 s1 starting at +/ 3  105 s1), and SLP (solid contours every 4 hPa)

  41. 0000 UTC 21 Sep 1995 H 1000–500-hPa thickness (dashed every 6 dam), 700-hPa geo. relative vorticity (shaded every 3  105 s1 starting at +/ 3  105 s1), and SLP (solid contours every 4 hPa)

  42. 0600 UTC 21 Sep 1995 H 1000–500-hPa thickness (dashed every 6 dam), 700-hPa geo. relative vorticity (shaded every 3  105 s1 starting at +/ 3  105 s1), and SLP (solid contours every 4 hPa)

  43. 1200 UTC 21 Sep 1995 H 1000–500-hPa thickness (dashed every 6 dam), 700-hPa geo. relative vorticity (shaded every 3  105 s1 starting at +/ 3  105 s1), and SLP (solid contours every 4 hPa)

  44. 1800 UTC 21 Sep 1995 H 1000–500-hPa thickness (dashed every 6 dam), 700-hPa geo. relative vorticity (shaded every 3  105 s1 starting at +/ 3  105 s1), and SLP (solid contours every 4 hPa)

  45. 0000 UTC 22 Sep 1995 H 1000–500-hPa thickness (dashed every 6 dam), 700-hPa geo. relative vorticity (shaded every 3  105 s1 starting at +/ 3  105 s1), and SLP (solid contours every 4 hPa)

  46. 0600 UTC 22 Sep 1995 H 1000–500-hPa thickness (dashed every 6 dam), 700-hPa geo. relative vorticity (shaded every 3  105 s1 starting at +/ 3  105 s1), and SLP (solid contours every 4 hPa)

  47. 1200 UTC 22 Sep 1995 H 1000–500-hPa thickness (dashed every 6 dam), 700-hPa geo. relative vorticity (shaded every 3  105 s1 starting at +/ 3  105 s1), and SLP (solid contours every 4 hPa)

  48. 1800 UTC 22 Sep 1995 H H 1000–500-hPa thickness (dashed every 6 dam), 700-hPa geo. relative vorticity (shaded every 3  105 s1 starting at +/ 3  105 s1), and SLP (solid contours every 4 hPa)

  49. 0000 UTC 23 Sep 1995 H H 1000–500-hPa thickness (dashed every 6 dam), 700-hPa geo. relative vorticity (shaded every 3  105 s1 starting at +/ 3  105 s1), and SLP (solid contours every 4 hPa)

  50. Arctic Outbreak: A Rare Anticyclone Event Count of ERA-40 2.5° ReanalysisSLP ≥ 1035 hPa(4x daily, Sep 1958–2002) Image adapted from Doody (2007) Anticyclone associated with Arctic outbreak accounts for all SLP values ≥ 1035 hPa east of Rockies in 45-yr Sep climatology (Doody 2007)  At least a 1-in-45-yr event

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