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A Multiscale Analysis of the Inland Reintensification of Tropical Cyclone Danny (1997) within an Equatorward Jet-Entrance Region. Matthew S. Potter, Lance F. Bosart, and Daniel Keyser Department of Earth and Atmospheric Sciences University at Albany, SUNY, Albany, NY. NROW-XIII
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A Multiscale Analysis of the Inland Reintensification of Tropical Cyclone Danny (1997) within an Equatorward Jet-Entrance Region Matthew S. Potter, Lance F. Bosart, and Daniel Keyser Department of Earth and Atmospheric Sciences University at Albany, SUNY, Albany, NY NROW-XIII Thursday 3 November 2011 Support Provided By UCAR/NCEP Grant S1071092
Overview • Motivation and Objectives • Data and Methodology • TC Danny (1997) Case Study • TC Camille (1969) Case Study • Concluding Remarks
Motivation • Documentation of inland reintensifying tropical cyclones (TCs) is scarce: • Bosart and Lackmann (1995): TC David (1979) • Bassil and Morgan (2006): TC Danny (1997) • Evans et al. (2011): TC Erin (2007)
Objectives • Identify inland reintensifying TCs during a 61-yr time period (1950–2010) • Investigate the physical mechanisms that enable a TC to reintensify inland
Data and Methodology • Inland Reintensifying TCs (1950–2010) • TCs which may have reintensified inland (“candidate cases”) were selected subjectively based on information gathered from • NHC best-track data • Archived surface charts from NCDC on microfilm • 2.5° NCEP–NCAR Reanalysis datasets • Subjective criteria were employed to identify inland reintensifying TCs
Data and Methodology • Subjective criteria used to create a list of inland reintensifying TCs • Minimum central MSLP decreased by 2 hPa and/or maximum sustained wind speed increased by 5 kt in a 6-h time period • Central circulation (i.e., eye) of the TC remained inland throughout reintensification • 500-hPa wind speed was less than or equal to 30 kt • Vertically stacked, warm-core was maintained or enhanced during reintensification
Data and Methodology • TC Danny Case Study • Used 0.5° Climate Forecast System Reanalysis (CFSR) datasets to produce maps and cross sections • Employed a potential vorticity perspective to help elucidate the TC-jet interaction • Used WSR-88D radar data and satellite imagery from Unidata–Wisconsin data stream to identify changes in precipitation structure • TC Camille Case Study • Used 2.5° ECMWF 40-yr Reanalysis (ERA-40) datasets to produce maps and cross sections
Inland Reintensifying TCs (1950–2010) • Every TC had an interaction with a upper-level jet except Erin (2007) • TC Danny had the largest pressure fall (12 hPa) and wind speed increase (15 m s-1) inland compared to other TCs in the climatology
Overview of TC Danny Track where TC Danny reintensified inland 960 mm of rain fell over Dauphin Island 1800 UTC 24 July 1000 hPa 40 kt 0000 UTC 24 July 1012 hPa 20 kt 0000 UTC Locations 0000 UTC 19 July 984 hPa 70 kt
Overview of TC Danny 250-hPa wind speed (shaded, m s-1), 1000–500-hPa thickness (dashed red, dam), and MSLP (solid black, hPa)
Overview of TC Danny 250-hPa wind speed (shaded, m s-1), 1000–500-hPa thickness (dashed red, dam), and MSLP (solid black, hPa)
Overview of TC Danny 250-hPa wind speed (shaded, m s-1), 1000–500-hPa thickness (dashed red, dam), and MSLP (solid black, hPa)
Overview of TC Danny 250-hPa wind speed (shaded, m s-1), 1000–500-hPa thickness (dashed red, dam), and MSLP (solid black, hPa)
Overview of TC Danny 250-hPa wind speed (shaded, m s-1), 1000–500-hPa thickness (dashed red, dam), and MSLP (solid black, hPa)
Overview of TC Danny 250-hPa wind speed (shaded, m s-1), 1000–500-hPa thickness (dashed red, dam), and MSLP (solid black, hPa)
Overview of TC Danny 250-hPa wind speed (shaded, m s-1), 1000–500-hPa thickness (dashed red, dam), and MSLP (solid black, hPa)
Overview of TC Danny 250-hPa wind speed (shaded, m s-1), 1000–500-hPa thickness (dashed red, dam), and MSLP (solid black, hPa)
Cross Section and Dynamic Tropopause Map PV (shaded every 1 PVU), θ (solid black, every 5 K), and the wind component normal to the cross section (dotted green every 5 m s-1) • Potential temperature (shaded every 5 K), winds (barbs in kt), and 925–850-hPa layer-averaged relative vorticity (solid black every 0.5 × 10-4 s-1) Relatively Low Shear Environment Under Anticyclone
Cross Section and Dynamic Tropopause Map PV (shaded every 1 PVU), θ (solid black, every 5 K), and the wind component normal to the cross section (dotted green every 5 m s-1) • Potential temperature (shaded every 5 K), winds (barbs in kt), and 925–850-hPa layer-averaged relative vorticity (solid black every 0.5 × 10-4 s-1)
Cross Section and Dynamic Tropopause Map PV (shaded every 1 PVU), θ (solid black, every 5 K), and the wind component normal to the cross section (dotted green every 5 m s-1) • Potential temperature (shaded every 5 K), winds (barbs in kt), and 925–850-hPa layer-averaged relative vorticity (solid black every 0.5 × 10-4 s-1)
Cross Section and Dynamic Tropopause Map PV (shaded every 1 PVU), θ (solid black, every 5 K), and the wind component normal to the cross section (dotted green every 5 m s-1) • Potential temperature (shaded every 5 K), winds (barbs in kt), and 925–850-hPa layer-averaged relative vorticity (solid black every 0.5 × 10-4 s-1)
Cross Section and Dynamic Tropopause Map PV (shaded every 1 PVU), θ (solid black, every 5 K), and the wind component normal to the cross section (dotted green every 5 m s-1) • Potential temperature (shaded every 5 K), winds (barbs in kt), and 925–850-hPa layer-averaged relative vorticity (solid black every 0.5 × 10-4 s-1)
Cross Section and Dynamic Tropopause Map PV (shaded every 1 PVU), θ (solid black, every 5 K), and the wind component normal to the cross section (dotted green every 5 m s-1) • Potential temperature (shaded every 5 K), winds (barbs in kt), and 925–850-hPa layer-averaged relative vorticity (solid black every 0.5 × 10-4 s-1)
Cross Section and Dynamic Tropopause Map PV (shaded every 1 PVU), θ (solid black, every 5 K), and the wind component normal to the cross section (dotted green every 5 m s-1) • Potential temperature (shaded every 5 K), winds (barbs in kt), and 925–850-hPa layer-averaged relative vorticity (solid black every 0.5 × 10-4 s-1)
Cross Section and Dynamic Tropopause Map PV (shaded every 1 PVU), θ (solid black, every 5 K), and the wind component normal to the cross section (dotted green every 5 m s-1) • Potential temperature (shaded every 5 K), winds (barbs in kt), and 925–850-hPa layer-averaged relative vorticity (solid black every 0.5 ×10-4 s-1)
Cross Section and Dynamic Tropopause Map PV (shaded every 1 PVU), θ (solid black, every 5 K), and the wind component normal to the cross section (dotted green every 5 m s-1) • Potential temperature (shaded every 5 K), winds (barbs in kt), and 925–850-hPa layer-averaged relative vorticity (solid black every 0.5 × 10-4 s-1)
Radar and Satellite Imagery GOES-8 Visible Image 1815 UTC 22 July KBMX Base Reflectivity 1813 UTC 22 July
Radar and Satellite Imagery GOES-8 Visible Image 2315 UTC 22 July KBMX Base Reflectivity 0013 UTC 23 July
Radar and Satellite Imagery KFFC Base Reflectivity 0611 UTC 23 July GOES-8 Infrared Image 0615 UTC 23 July
Radar and Satellite Imagery KFFC Base Reflectivity 1218 UTC 23 July GOES-8 Visible Image 1215 UTC 23 July
Radar and Satellite Imagery GOES-8 Visible Image 1815 UTC 23 July KGSP Base Reflectivity 1823 UTC 23 July
Radar and Satellite Imagery KGSP Base Reflectivity 0015 UTC 24 July GOES-8 Visible Image 2315 UTC 23 July
Radar and Satellite Imagery KCAE Base Reflectivity 0617 UTC 24 July GOES-8 Infrared Image 0615 UTC 24 July
Radar and Satellite Imagery KAKQ Base Reflectivity 1318 UTC 24 July GOES-8 Visible Image 1313 UTC 24 July
Radar and Satellite Imagery GOES-8 Visible Image 1815 UTC 24 July KAKQ Base Reflectivity 1814 UTC 24 July
Diabatic Outflow at 1800 UTC 24 July 250-hPa wind speed (color shading in kt), 250-hPa potential vorticity (solid gray every 1 PVU), 250-hPa relative humidity (gray shading in %), 600–400-hPa layer-averaged ω (red every 4 × 10-3 hPa s-1, negative values only), 300–200 hPa layer-averaged irrotational wind (arrows, m s-1) Diabatic outflow from convection around TC Danny strengthens jet
Ageostrophic Circulation and Frontogenesis Frontogenesis (shaded in K (100 km)-1 (3 h)-1), θ (solid black every 5 K), ω (dotted red every --5 × 10-3 hPa s-1), wind component normal to the cross section (solid brown, m s-1), and the ageostrophic wind component tangential to the cross section (arrows, m s-1) 5 cm/s
Ageostrophic Circulation and Frontogenesis Frontogenesis (shaded in K (100 km)-1 (3 h)-1), θ (solid black every 5 K), ω (dotted red every --5 × 10-3 hPa s-1), wind component normal to the cross section (solid brown, m s-1), and the ageostrophic wind component tangential to the cross section (arrows, m s-1) 5 cm/s
Ageostrophic Circulation and Frontogenesis Frontogenesis (shaded in K (100 km)-1 (3 h)-1), θ (solid black every 5 K), ω (dotted red every --5 × 10-3 hPa s-1), wind component normal to the cross section (solid brown, m s-1), and the ageostrophic wind component tangential to the cross section (arrows, m s-1) 5 cm/s
Ageostrophic Circulation and Frontogenesis Frontogenesis (shaded in K (100 km)-1 (3 h)-1), θ (solid black every 5 K), ω (dotted red every --5 × 10-3 hPa s-1), wind component normal to the cross section (solid brown, m s-1), and the ageostrophic wind component tangential to the cross section (arrows, m s-1) 5 cm/s
Ageostrophic Circulation and Frontogenesis Frontogenesis (shaded in K (100 km)-1 (3 h)-1), θ (solid black every 5 K), ω (dotted red every --5 × 10-3 hPa s-1), wind component normal to the cross section (solid brown, m s-1), and the ageostrophic wind component tangential to the cross section (arrows, m s-1) 5 cm/s
Ageostrophic Circulation and Frontogenesis Frontogenesis (shaded in K (100 km)-1 (3 h)-1), θ (solid black every 5 K), ω (dotted red every --5 × 10-3 hPa s-1), wind component normal to the cross section (solid brown, m s-1), and the ageostrophic wind component tangential to the cross section (arrows, m s-1) 5 cm/s
Ageostrophic Circulation and Frontogenesis Frontogenesis (shaded in K (100 km)-1 (3 h)-1), θ (solid black every 5 K), ω (dotted red every --5 × 10-3 hPa s-1), wind component normal to the cross section (solid brown, m s-1), and the ageostrophic wind component tangential to the cross section (arrows, m s-1) 5 cm/s
Ageostrophic Circulation and Frontogenesis Frontogenesis (shaded in K (100 km)-1 (3 h)-1), θ (solid black every 5 K), ω (dotted red every --5 × 10-3 hPa s-1), wind component normal to the cross section (solid brown, m s-1), and the ageostrophic wind component tangential to the cross section (arrows, m s-1) Frontogenesis 5 cm/s
Ageostrophic Circulation and Frontogenesis Frontogenesis (shaded in K (100 km)-1 (3 h)-1), θ (solid black every 5 K), ω (dotted red every --5 × 10-3 hPa s-1), wind component normal to the cross section (solid brown, m s-1), and the ageostrophic wind component tangential to the cross section (arrows, m s-1) Frontogenesis 5 cm/s
Danny Remarks • Danny Case Study • The inland reintensification of TC Danny can be attributed to: (1) Frontogenesis along the lower-tropospheric baroclinic zone and the associated tropospheric-deep ascent beneath the equatorward entrance region of the upper-level jet (2) Deep convection that provided a source of diabatic heating and reinforced the ascent near the storm center (3) Upper-tropospheric PV reduction north of the storm center that strengthened the meridional PV gradient and the associated jet (4) Lower-tropospheric vorticity growth in an environment that favored enhanced ascent near the storm center
Overview of TC Camille 690 mm of rain fell over West Nelson County Severe Inland Flooding (153 fatalities) 0000 UTC 20 August 1005 hPa 25 kt 0000 UTC 18 August 909 hPa 165 kt 0000 UTC Locations
Overview of TC Camille 250-hPa wind speed (shaded, m s-1), 1000–500-hPa thickness (dashed red, dam), and MSLP (solid black, hPa)
Overview of TC Camille 250-hPa wind speed (shaded, m s-1), 1000–500-hPa thickness (dashed red, dam), and MSLP (solid black, hPa)
Overview of TC Camille 250-hPa wind speed (shaded, m s-1), 1000–500-hPa thickness (dashed red, dam), and MSLP (solid black, hPa)