Here a TC, There a TC, Everywhere a TC: The "Spin" on the Active Part of the North Atlantic 2008 TC Season Lance F. Bosart, Thomas J. Galarneau, Jr., and.

Here a TC, There a TC, Everywhere a TC: The "Spin" on the Active Part of the North Atlantic 2008 TC Season Lance F. Bosart, Thomas J. Galarneau, Jr., and Jason M. Cordeira Department of Earth and Atmospheric Sciences University at Albany SUNY, Albany, NY Tenth Northeast Regional Operational Workshop Albany, New York 6 November 2008

MOTIVATION: Multiple TC interactions. A potpourri of TC-related mesoscale precipitation features. The many United States tropical cyclone (TC) landfalls during the 2008 North Atlantic TC season provided a serendipitous opportunity to study:

OUTLINE: Overview of multiple TC interactions: Gustav Hanna Ike Josephine North Atlantic non-developer Unnamed subtropical storm (ST) Overview of TC-related mesoscale precipitation features: Hanna and Unnamed ST A "pseudo" predecessor rain event (PRE) A coastal front Ike A "pre PRE" (TC Lowell and Bay of Campeche null TC) A main event PRE

Interacting TCs

Gustav Hanna Ike Josephine Lowell DT  (K), wind (kt), 925–850 hPa  (10  4 s  1 ) Ridge PV streamers

Gustav Hanna Ike Josephine Lowell DT  (K), wind (kt), 925–850 hPa  (10  4 s  1 ) Ridge PV streamers Gustav Ridge

Gustav Hanna Ike Josephine Lowell DT  (K), wind (kt), 925–850 hPa  (10  4 s  1 ) Gustav Ridge Hanna Ridge Foldover Ridge PV streamers

Gustav Hanna Ike Josephine Lowell DT  (K), wind (kt), 925–850 hPa  (10  4 s  1 ) Gustav/Hanna Ridge Cutoff Ridge PV streamers

Gustav Hanna Ike Josephine Lowell DT  (K), wind (kt), 925–850 hPa  (10  4 s  1 ) Gustav/Hanna Ridge PV streamers

Gustav Hanna Ike Josephine Lowell DT  (K), wind (kt), 925–850 hPa  (10  4 s  1 ) PV streamers

Gustav Hanna Ike Josephine Lowell DT  (K), wind (kt), 925–850 hPa  (10  4 s  1 ) W W=Ike upper-level ridge PV streamers

Gustav Hanna Ike Josephine Lowell DT  (K), wind (kt), 925–850 hPa  (10  4 s  1 ) W1W1 W2W2 W=Ike upper-level ridge PV streamers

Overview of Predecessor Rain Events (PREs) Cote (2007)

Predecessor Rain Events (PREs) Coherent area of rain displaced poleward of tropical cyclone (TC) Moisture transport from TC toward PRE Max rainfall rates typically ≥ 100 mm (24 h)  1 Time lag between PRE and TC passage ~36 h ~1000 km Event Duration ~12 h Bosart and Carr (1978) conceptual model of antecedent rainfall for Tropical Cyclone Agnes (1972) Detailed study of PREs in Cote (2007)

PRE TRACK-RELATIVE POSITIONS 26 12 9 PRE Locations Relative to TC Track 1998–2006 Cote (2007) 47 PREs associated with 21 TCs were identified (~2 PREs per TC) ~1/3 of all U.S. landfalling TCs produced at least one PRE Five cases where TC did not make U.S. landfall

COMPOSITES: Time = 0 h 700 hPa h (dam) and upward vertical motion (μb s -1 ) 925 hPa h (dam), θ e (K), and 200 hPa wind speed (m s -1 ) Center of composite TC Centroid of 1 st composite PRE Trough axis Ridge axis θ e -Ridge axis Cote (2007)

Hanna: 28 Aug - 7 Sep 2008 Coastal Front and "Pseudo-PRE" in Hanna

http://www.atmos.albany.edu/facstaff/rmctc/DTmaps/animSelect.php SLP (hPa), 1000-500 hPa thickness (dam), and 250 hPa isotachs (kt)

GFS24 VT12Z 6 Sep08GFS30 VT18Z 6 Sep08 SLP (hPa), 1000-500 hPa thickness (dam), 2-m temperatures (°C), and 6-h forecast rainfall (inches)

PW (mm): 1800 UTC 5 September 2008 Base Reflectivity (dBZ): 0900 UTC 6 September 2008 PW (shaded; mm), 250 hPa heights (black contours, dam), 700 hPa winds (kt), and 925-850 hPa mean relative vorticity (magenta contours, every 0.5 x 10 -4 s -1 )

1830 UTC 5 Sep 20080230 UTC 6 Sep 2008 http://www.atmos.albany.edu/student/cordeira/WEB/GFS_ARCHIVE/

0830 UTC 6 Sep 20081730 UTC 6 Sep 2008

http://www.atmos.albany.edu/student/cordeira/WEB/GFS_ARCHIVE/ 2030 UTC 6 Sep 20082330 UTC 6 Sep 2008

Midwest PRE with TC Ike: 11-14 September 2008

Source: http://www.hpc.ncep.noaa.gov/npvu/archive/rfc.shtml QPE (inches) for 24-h periods ending 1200 UTC 11 (left) and 12 (right) September 2008

Source: http://www.hpc.ncep.noaa.gov/npvu/archive/rfc.shtml QPE (inches) for 24-h periods ending 1200 UTC 13 (left) and 14 (right) September 2008

1200 UTC 6 September 20080000 UTC 8 September 2008 PW (shaded; mm), 250 hPa heights (black contours, dam), 700 hPa winds (kt), and 925-850 hPa mean relative vorticity (magenta contours, every 0.5 x 10 -4 s -1 ) http://www.atmos.albany.edu/student/cordeira/WEB/GFS_ARCHIVE/

PW (shaded; mm; from 700 hPa (left) and from surface (right)), 250 hPa heights (black contours, dam), 700 hPa winds (kt), and 925-850 hPa mean relative vorticity (magenta contours, every 0.5 x 10 -4 s -1 ) 1200 UTC 11 September 2008

Potential temperature (shaded, K) and winds (kt) on the dynamic tropopause (2 PVU surface), and 925-850 hPa layer-mean relative vorticity (black contours every 0.5 x 10 -4 s -1 ) 1200 UTC 6 September 20080000 UTC 8 September 2008 http://www.atmos.albany.edu/student/cordeira/WEB/GFS_ARCHIVE/

http://www.atmos.albany.edu/student/cordeira/WEB/RADSFC/radar.html 1202 UTC 11 September 20081803 UTC 11 September 2008

Source: http://weather.uwyo.edu/upperair/sounding.html

Source: http://www.rap.ucar.edu/weather/

2145 UTC 12 Sep'081445 UTC 13 Sep'08 2045 UTC 13 Sep'08

00Z/13 06Z/13 12Z/13 18Z/13 ORD rainfall in 6-h periods: 00–06 UTC 13  5.1 mm 06–12 UTC 13  75.4 mm 12–18 UTC 13  72.6 mm 18–00 UTC 13  19.8 mm PRE Ike Ike tropical moisture arrives by 06 UTC L L L L WSR-88D base reflectivity mosaic Source: NCAR case-selection archive ORD

06Z/14 12Z/14 15Z/14 18Z/14 ORD rainfall in 6-h periods: 00–06 UTC 14  1.3 mm 06–12 UTC 14  5.6 mm 12–18 UTC 14  25.7 mm 18–00 UTC 14  5.3 mm Ike ORD

1200 UTC 13 September 2008 700 hPa h (dam), 700 hPa wind (m s  1 ) 700 hPa ascent (10  3 hPa s  1 ) 900–400 hPa relative humidity (%) 925 hPa h (dam), 925 hPa wind (m s  1 ) 925 hPa  e (K) 200 hPa wind speed (m s  1 ) Ike PRE H H

1200 UTC 13 September 2008 925 hPa h (dam) 925 hPa  e (K) 200 hPa wind speed (m s  1 ) 0000 UTC 13 September 2008 250 hPa h (dam), 700 hPa  (10  5 s  1 ) precipitable water (mm), 850–500 hPa mean wind (m s  1 ) L L Ike PRE 56 mm

1200 UTC 13 September 2008 925 hPa h (dam) 925 hPa  e (K) 200 hPa wind speed (m s  1 ) 0000 UTC 13 September 2008 250 hPa h (dam), 700 hPa  (10  5 s  1 ) precipitable water (mm), 850–500 hPa mean wind (m s  1 ) L L Ike PRE

 t = 3 hours  t = 1 hour 500 700 850 Pressure (hPa) Lubbock (LBB), TX: Backward Trajectories for 96 h Ending 1200 UTC 11 September 2008 11 Sep Wettest day 189.5 mm LBB

 t = 3 hours  t = 1 hour 500 700 850 Pressure (hPa) Wichita (ICT), KS: Backward Trajectories for 96 h Ending 0600 UTC 13 September 2008 12 Sep Wettest day 261.9 mm ICT

 t = 3 hours  t = 1 hour 500 700 850 Pressure (hPa) Chicago (ORD), IL: Backward Trajectories for 96 h Ending 1800 UTC 13 September 2008 13 Sep Wettest day 168.7 mm ORD

SUMMARY: Outflow from Hanna may have helped to weaken Ike from a Cat 4 to a high cat 2 storm. Anticyclonic outflow from Hanna/Ike may have enhanced the PV tail that disrupted Josephine. "Psuedo-PRE" ahead of Hanna moved too fast to dump excessive amounts of rain. Coastal front in Hanna was a focus of heavy rainfall from Delmarva to eastern New England. Classic PRE ahead of Ike also fed off midlevel moisture from Lowell and a pre-existing tropical moisture plume over the western Caribbean.

Here a TC, There a TC, Everywhere a TC: The "Spin" on the Active Part of the North Atlantic 2008 TC Season Lance F. Bosart, Thomas J. Galarneau, Jr., and.

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Here a TC, There a TC, Everywhere a TC: The "Spin" on the Active Part of the North Atlantic 2008 TC Season Lance F. Bosart, Thomas J. Galarneau, Jr., and.

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Presentation on theme: "Here a TC, There a TC, Everywhere a TC: The "Spin" on the Active Part of the North Atlantic 2008 TC Season Lance F. Bosart, Thomas J. Galarneau, Jr., and."— Presentation transcript:

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