Recurving Typhoons as Precursors to an Early Season Arctic Outbreak over the Continental U.S.Heather M. Archambault, Lance F. Bosart, and Daniel KeyserDept. of Earth and Atmospheric Sciences University at Albany, State University of New YorkSuper Typhoon Oscar, 15 Sep 1995 (Source: NCDC website)NROW IX

Wednesday, 7 November 2007 NSF Grant ATM-0434189

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)

OverviewImpacts of the 2022 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. PlainsSurface Temp. < 0C, Week of 1723 Sep 1995

1822 Sep 1995: Extreme Temperatures5-d mean 925-hPa temp. (contoured every 2C)5-d mean 925-hPa temp. anomaly (contoured every 2C) 5-d mean 925-hPa temp. anomalies exceed 8C over central and northern Plains, and +14C over northern Alaska and Arctic Ocean

Presentation OutlineData sources

Key Arctic outbreak mechanisms W. Pacific TY recurvature and ridge amplificationPacificNorth American downstream developmentWestern North American blockingNorth American surface anticyclogenesis

Summary and conclusions

Data Sources2.5 ECMWF ERA-40 reanalysis (sea level pressure (SLP) fields only)

1.125 ECMWF ERA-40 reanalysis

2.5 NCEPNCAR 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/)

1: TY Recurvature and Ridge AmplificationThree typhoons recurve in the West Pacific within a 7-d period (1622 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 (1520 Sep)

STY Oscar (1219 Sep 1995)Key: Tropical Depression Weak Tropical Storm Strong Tropical Storm Typhoon Extratropical CycloneJapan Meteorological Agency Best Track Plot Large circles delineate 0000 and 1200 UTC Small circles delineate 0300, 0600, 0900, 1500, and 2100 UTC

STY Oscar (1219 Sep 1995)Key: Tropical Depression Weak Tropical Storm Strong Tropical Storm Typhoon Extratropical CycloneAt 30N, 1200 UTC 16 SepJapan Meteorological Agency Best Track Plot 300-hPa vel. potential (contoured every 2 106 m2 s1), irrotational wind (plotted starting at 10 kt) 925-hPa rel. vorticity (shaded starting at 5 105 s1) Large circles delineate 0000 and 1200 UTC Small circles delineate 0300, 0600, 0900, 1500, and 2100 UTC

TY Polly (1423 Sep 1995)At 30N, 1200 UTC 20 SepKey: Tropical Depression Weak Tropical Storm Strong Tropical Storm Typhoon Extratropical CycloneJapan Meteorological Agency Best Track Plot 300-hPa vel. potential (contoured every 2 106 m2 s1), irrotational wind (plotted starting at 10 kt) 925-hPa rel. vorticity (shaded starting at 5 105 s1) Large circles delineate 0000 and 1200 UTC Small circles delineate 0300, 0600, 0900, 1500, and 2100 UTC

STY Ryan (1525 Sep 1995)At 30N, 1200 UTC 23 SepKey: Tropical Depression Weak Tropical Storm Strong Tropical Storm Typhoon Extratropical CycloneJapan Meteorological Agency Best Track Plot 300-hPa vel. potential (contoured every 2 106 m2 s1), irrotational wind (plotted starting at 10 kt) 925-hPa rel. vorticity (shaded starting at 5 105 s1) Large circles delineate 0000 and 1200 UTC Small circles delineate 0300, 0600, 0900, 1500, and 2100 UTC

Circulation Before TY Recurvature Events3-d Mean Plot: 1214 Sep 1995Oscar Polly 300-hPa streamfunction (thick lines every 10 106 m2 s1) and nondivergent wind speed (shaded every 5 m s1 starting at 35 m s1); SLP (thin lines every 4 hPa)

Circulation During STY Oscar Recurvature3-d Mean Plot: 1517 Sep 1995Ryan Oscar Polly 300-hPa streamfunction (thick lines every 10 106 m2 s1) and nondivergent wind speed (shaded every 5 m s1 starting at 35 m s1); SLP (thin lines every 4 hPa)

Circulation During TY Polly Recurvature3-d Mean Plot: 1820 Sep 1995Ryan Oscar Polly 300-hPa streamfunction (thick lines every 10 106 m2 s1) and nondivergent wind speed (shaded every 5 m s1 starting at 35 m s1); SLP (thin lines every 4 hPa)

2: Downstream Development

Upper-level ridge amplification results in downstream development across Pacific Ocean and North America (1622 Sep)

1200 UTC 16 Sep 1995300-hPa streamfunction (contoured every 10 106 m2 s1), nondivergent wind (plotted in kt), and meridional nondivergent wind speed (shaded every 10 m s1 according to color bar)

1200 UTC 18 Sep 1995300-hPa streamfunction (contoured every 10 106 m2 s1), nondivergent wind (plotted in kt), and meridional nondivergent wind speed (shaded every 10 m s1 according to color bar)

1200 UTC 20 Sep 1995300-hPa streamfunction (contoured every 10 106 m2 s1), nondivergent wind (plotted in kt), and meridional nondivergent wind speed (shaded every 10 m s1 according to color bar)

1200 UTC 22 Sep 1995300-hPa streamfunction (contoured every 10 106 m2 s1), nondivergent wind (plotted in kt), and meridional nondivergent wind speed (shaded every 10 m s1 according to color bar)

3: Western North American BlockingWestern 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) (1622 Sep)

1200 UTC 16 Sep 19951000500-hPa thickness (dashed every 6 dam), 300-hPa wind speed (shaded every 5 m s1 starting at 45 m s1, and sea level pressure (solid contours every 4 hPa)

1200 UTC 17 Sep 19951000500-hPa thickness (dashed every 6 dam), 300-hPa wind speed (shaded every 5 m s1 starting at 45 m s1, and sea level pressure (solid contours every 4 hPa)

1200 UTC 18 Sep 19951000500-hPa thickness (dashed every 6 dam), 300-hPa wind speed (shaded every 5 m s1 starting at 45 m s1, and sea level pressure (solid contours every 4 hPa)

1200 UTC 19 Sep 19951000500-hPa thickness (dashed every 6 dam), 300-hPa wind speed (shaded every 5 m s1 starting at 45 m s1, and sea level pressure (solid contours every 4 hPa)

1200 UTC 20 Sep 19951000500-hPa thickness (dashed every 6 dam), 300-hPa wind speed (shaded every 5 m s1 starting at 45 m s1, and sea level pressure (solid contours every 4 hPa)

1200 UTC 21 Sep 19951000500-hPa thickness (dashed every 6 dam), 300-hPa wind speed (shaded every 5 m s1 starting at 45 m s1, and sea level pressure (solid contours every 4 hPa)

1200 UTC 22 Sep 19951000500-hPa thickness (dashed every 6 dam), 300-hPa wind speed (shaded every 5 m s1 starting at 45 m s1, and sea level pressure (solid contours every 4 hPa)

4: North American Surface AnticyclogenesisAnticyclonic wave breaking results in surface anticyclogenesis over central Canada and initial equatorward movement along the Rockies (1823 Sep)

Strength and movement of surface anticyclone is associated with advection of anticyclonic geostrophic relative vorticity by the thermal wind (SutcliffeTrenberth approximation of quasigeostrophic forcing for vertical motion; Trenberth 1978)

0000 UTC 18 Sep 1995H1000500-hPa thickness (dashed every 6 dam), 700-hPa geo. relative vorticity (shaded every 3 105 s1 starting at +/ 3 105 s1), and SLP (solid contours every 4 hPa)

0600 UTC 18 Sep 1995H1000500-hPa thickness (dashed every 6 dam), 700-hPa geo. relative vorticity (shaded every 3 105 s1 starting at +/ 3 105 s1), and SLP (solid contours every 4 hPa)

1200 UTC 18 Sep 1995H1000500-hPa thickness (dashed every 6 dam), 700-hPa geo. relative vorticity (shaded every 3 105 s1 starting at +/ 3 105 s1), and SLP (solid contours every 4 hPa)

1800 UTC 18 Sep 1995H1000500-hPa thickness (dashed every 6 dam), 700-hPa geo. relative vorticity (shaded every 3 105 s1 starting at +/ 3 105 s1), and SLP (solid contours every 4 hPa)

0000 UTC 19 Sep 1995H1000500-hPa thickness (dashed every 6 dam), 700-hPa geo. relative vorticity (shaded every 3 105 s1 starting at +/ 3 105 s1), and SLP (solid contours every 4 hPa)

0600 UTC 19 Sep 1995HH1000500-hPa thickness (dashed every 6 dam), 700-hPa geo. relative vorticity (shaded every 3 105 s1 starting at +/ 3 105 s1), and SLP (solid contours every 4 hPa)

1200 UTC 19 Sep 1995HH1000500-hPa thickness (dashed every 6 dam), 700-hPa geo. relative vorticity (shaded every 3 105 s1 starting at +/ 3 105 s1), and SLP (solid contours every 4 hPa)

1800 UTC 19 Sep 1995H1000500-hPa thickness (dashed every 6 dam), 700-hPa geo. relative vorticity (shaded every 3 105 s1 starting at +/ 3 105 s1), and SLP (solid contours every 4 hPa)

0000 UTC 20 Sep 1995H1000500-hPa thickness (dashed every 6 dam), 700-hPa geo. relative vorticity (shaded every 3 105 s1 starting at +/ 3 105 s1), and SLP (solid contours every 4 hPa)

0600 UTC 20 Sep 1995H1000500-hPa thickness (dashed every 6 dam), 700-hPa geo. relative vorticity (shaded every 3 105 s1 starting at +/ 3 105 s1), and SLP (solid contours every 4 hPa)

1200 UTC 20 Sep 1995H1000500-hPa thickness (dashed every 6 dam), 700-hPa geo. relative vorticity (shaded every 3 105 s1 starting at +/ 3 105 s1), and SLP (solid contours every 4 hPa)

1800 UTC 20 Sep 1995H1000500-hPa thickness (dashed every 6 dam), 700-hPa geo. relative vorticity (shaded every 3 105 s1 starting at +/ 3 105 s1), and SLP (solid contours every 4 hPa)

0000 UTC 21 Sep 1995H1000500-hPa thickness (dashed every 6 dam), 700-hPa geo. relative vorticity (shaded every 3 105 s1 starting at +/ 3 105 s1), and SLP (solid contours every 4 hPa)

0600 UTC 21 Sep 1995H1000500-hPa thickness (dashed every 6 dam), 700-hPa geo. relative vorticity (shaded every 3 105 s1 starting at +/ 3 105 s1), and SLP (solid contours every 4 hPa)

1200 UTC 21 Sep 1995H1000500-hPa thickness (dashed every 6 dam), 700-hPa geo. relative vorticity (shaded every 3 105 s1 starting at +/ 3 105 s1), and SLP (solid contours every 4 hPa)

1800 UTC 21 Sep 1995H1000500-hPa thickness (dashed every 6 dam), 700-hPa geo. relative vorticity (shaded every 3 105 s1 starting at +/ 3 105 s1), and SLP (solid contours every 4 hPa)

0000 UTC 22 Sep 1995H1000500-hPa thickness (dashed every 6 dam), 700-hPa geo. relative vorticity (shaded every 3 105 s1 starting at +/ 3 105 s1), and SLP (solid contours every 4 hPa)

0600 UTC 22 Sep 1995H1000500-hPa thickness (dashed every 6 dam), 700-hPa geo. relative vorticity (shaded every 3 105 s1 starting at +/ 3 105 s1), and SLP (solid contours every 4 hPa)

1200 UTC 22 Sep 1995H1000500-hPa thickness (dashed every 6 dam), 700-hPa geo. relative vorticity (shaded every 3 105 s1 starting at +/ 3 105 s1), and SLP (solid contours every 4 hPa)

1800 UTC 22 Sep 1995HH1000500-hPa thickness (dashed every 6 dam), 700-hPa geo. relative vorticity (shaded every 3 105 s1 starting at +/ 3 105 s1), and SLP (solid contours every 4 hPa)

0000 UTC 23 Sep 1995HH1000500-hPa thickness (dashed every 6 dam), 700-hPa geo. relative vorticity (shaded every 3 105 s1 starting at +/ 3 105 s1), and SLP (solid contours every 4 hPa)

Arctic Outbreak: A Rare Anticyclone EventAnticyclone 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 eventCount of ERA-40 2.5 Reanalysis SLP 1035 hPa(4x daily, Sep 19582002)Image adapted from Doody (2007)

Mechanisms Leading to Arctic OutbreakTY RecurvatureRidge Amplification1620 Sep 1995

Mechanisms Leading to Arctic OutbreakDownstream DevelopmentPersistent Cyclogenesis1722 Sep 1995

Mechanisms Leading to Arctic OutbreakAnticyclonic Wave BreakingAnticyclogenesis1822 Sep 1995

Mechanisms Leading to Arctic OutbreakTY RecurvatureRidge AmplificationDownstream DevelopmentPersistent CyclogenesisAnticyclonic Wave BreakingAnticyclogenesis1623 Sep 1995

Conclusions2022 September 1995 continental U.S. Arctic outbreak is directly linked to recurving western Pacific typhoons via downstream development

Surface anticyclone associated with Arctic outbreak is strongest September event in 2.5 ERA-40 dataset (19582002)

Arctic outbreak characteristics are generally similar to characteristics of other documented cases (e.g., upstream omega block, surface anticyclogenesis, precursor cold surge, mountain range channeling)

Apparent first documented case of an Arctic outbreak directly linked to upstream recurving tropical cyclones